diff --git a/.cron.yml b/.cron.yml
index e610ea687b4b..62e960ade236 100644
--- a/.cron.yml
+++ b/.cron.yml
@@ -121,4 +121,5 @@ jobs:
           by-project:
               # No default branch
               mozilla-central:
-                  - {hour: 10, minute: 0}
+                  - {weekday: 'Monday', hour: 10, minute: 0}
+                  - {weekday: 'Thursday', hour: 10, minute: 0}
diff --git a/accessible/base/TextAttrs.cpp b/accessible/base/TextAttrs.cpp
index 7655941c7f5b..52f14655838a 100644
--- a/accessible/base/TextAttrs.cpp
+++ b/accessible/base/TextAttrs.cpp
@@ -592,7 +592,7 @@ TextAttrsMgr::FontStyleTextAttr::
 
 TextAttrsMgr::FontWeightTextAttr::
   FontWeightTextAttr(nsIFrame* aRootFrame, nsIFrame* aFrame) :
-  TTextAttr<int32_t>(!aFrame)
+  TTextAttr<FontWeight>(!aFrame)
 {
   mRootNativeValue = GetFontWeight(aRootFrame);
   mIsRootDefined = true;
@@ -605,7 +605,7 @@ TextAttrsMgr::FontWeightTextAttr::
 
 bool
 TextAttrsMgr::FontWeightTextAttr::
-  GetValueFor(Accessible* aAccessible, int32_t* aValue)
+  GetValueFor(Accessible* aAccessible, FontWeight* aValue)
 {
   nsIContent* elm = nsCoreUtils::GetDOMElementFor(aAccessible->GetContent());
   if (elm) {
@@ -620,15 +620,16 @@ TextAttrsMgr::FontWeightTextAttr::
 
 void
 TextAttrsMgr::FontWeightTextAttr::
-  ExposeValue(nsIPersistentProperties* aAttributes, const int32_t& aValue)
+  ExposeValue(nsIPersistentProperties* aAttributes,
+              const FontWeight& aValue)
 {
   nsAutoString formattedValue;
-  formattedValue.AppendInt(aValue);
+  formattedValue.AppendFloat(aValue.ToFloat());
 
   nsAccUtils::SetAccAttr(aAttributes, nsGkAtoms::fontWeight, formattedValue);
 }
 
-int32_t
+FontWeight
 TextAttrsMgr::FontWeightTextAttr::
   GetFontWeight(nsIFrame* aFrame)
 {
@@ -645,8 +646,9 @@ TextAttrsMgr::FontWeightTextAttr::
   // bold font, i.e. synthetic bolding is used. IsSyntheticBold method is only
   // needed on Mac, but it is "safe" to use on all platforms.  (For non-Mac
   // platforms it always return false.)
-  if (font->IsSyntheticBold())
-    return 700;
+  if (font->IsSyntheticBold()) {
+    return FontWeight::Bold();
+  }
 
   // On Windows, font->GetStyle()->weight will give the same weight as
   // fontEntry->Weight(), the weight of the first font in the font group,
diff --git a/accessible/base/TextAttrs.h b/accessible/base/TextAttrs.h
index 3cc4ba356db7..e5dac1bab6ea 100644
--- a/accessible/base/TextAttrs.h
+++ b/accessible/base/TextAttrs.h
@@ -6,6 +6,7 @@
 #ifndef nsTextAttrs_h_
 #define nsTextAttrs_h_
 
+#include "mozilla/FontPropertyTypes.h"
 #include "nsCOMPtr.h"
 #include "nsColor.h"
 #include "nsString.h"
@@ -354,7 +355,7 @@ protected:
   /**
    * Class is used for the work with "font-weight" text attribute.
    */
-  class FontWeightTextAttr : public TTextAttr<int32_t>
+  class FontWeightTextAttr : public TTextAttr<mozilla::FontWeight>
   {
   public:
     FontWeightTextAttr(nsIFrame* aRootFrame, nsIFrame* aFrame);
@@ -363,13 +364,14 @@ protected:
   protected:
 
     // TTextAttr
-    virtual bool GetValueFor(Accessible* aAccessible, int32_t* aValue)
+    virtual bool GetValueFor(Accessible* aAccessible,
+                             mozilla::FontWeight* aValue)
       override;
     virtual void ExposeValue(nsIPersistentProperties* aAttributes,
-                             const int32_t& aValue) override;
+                             const mozilla::FontWeight& aValue) override;
 
   private:
-    int32_t GetFontWeight(nsIFrame* aFrame);
+    mozilla::FontWeight GetFontWeight(nsIFrame* aFrame);
   };
 
   /**
diff --git a/devtools/client/debugger/new/test/mochitest/browser.ini b/devtools/client/debugger/new/test/mochitest/browser.ini
index 79269fe2a3e8..cc1437ab295c 100644
--- a/devtools/client/debugger/new/test/mochitest/browser.ini
+++ b/devtools/client/debugger/new/test/mochitest/browser.ini
@@ -144,6 +144,7 @@ support-files =
 [browser_dbg-async-stepping.js]
 [browser_dbg-babel-breakpoint-console.js]
 [browser_dbg-babel-scopes.js]
+skip-if = ccov # Bug 1441545
 [browser_dbg-babel-stepping.js]
 [browser_dbg-babel-preview.js]
 skip-if = (os == "win" && ccov) # Bug 1448523
diff --git a/devtools/client/framework/test/browser.ini b/devtools/client/framework/test/browser.ini
index a6f443b16214..b544bb7c487d 100644
--- a/devtools/client/framework/test/browser.ini
+++ b/devtools/client/framework/test/browser.ini
@@ -82,6 +82,7 @@ skip-if = os == 'win' || debug # Bug 1282269, 1448084
 [browser_toolbox_keyboard_navigation.js]
 skip-if = os == "mac" # Full keyboard navigation on OSX only works if Full Keyboard Access setting is set to All Control in System Keyboard Preferences
 [browser_toolbox_options.js]
+[browser_toolbox_options_multiple_tabs.js]
 [browser_toolbox_options_disable_buttons.js]
 [browser_toolbox_options_disable_cache-01.js]
 [browser_toolbox_options_disable_cache-02.js]
diff --git a/devtools/client/framework/test/browser_toolbox_options.js b/devtools/client/framework/test/browser_toolbox_options.js
index 215d07ce51df..ad2b0c60adfb 100644
--- a/devtools/client/framework/test/browser_toolbox_options.js
+++ b/devtools/client/framework/test/browser_toolbox_options.js
@@ -332,11 +332,16 @@ async function testToggleWebExtensions() {
      "There should not be any checkbox for the unregistered WebExtensions");
 }
 
+function getToolNode(id) {
+  return panelWin.document.getElementById(id);
+}
+
 async function testToggleTools() {
   let toolNodes = panelWin.document.querySelectorAll(
     "#default-tools-box input[type=checkbox]:not([data-unsupported])," +
     "#additional-tools-box input[type=checkbox]:not([data-unsupported])");
-  let enabledTools = [...toolNodes].filter(node => node.checked);
+  let toolNodeIds = [...toolNodes].map(node => node.id);
+  let enabledToolIds = [...toolNodes].filter(node => node.checked).map(node => node.id);
 
   let toggleableTools = gDevTools.getDefaultTools()
                                  .filter(tool => {
@@ -358,39 +363,43 @@ async function testToggleTools() {
   }
 
   // Toggle each tool
-  for (let node of toolNodes) {
-    await toggleTool(node);
+  for (let id of toolNodeIds) {
+    await toggleTool(getToolNode(id));
   }
 
   // Toggle again to reset tool enablement state
-  for (let node of toolNodes) {
-    await toggleTool(node);
+  for (let id of toolNodeIds) {
+    await toggleTool(getToolNode(id));
   }
 
   // Test that a tool can still be added when no tabs are present:
   // Disable all tools
-  for (let node of enabledTools) {
-    await toggleTool(node);
+  for (let id of enabledToolIds) {
+    await toggleTool(getToolNode(id));
   }
   // Re-enable the tools which are enabled by default
-  for (let node of enabledTools) {
-    await toggleTool(node);
+  for (let id of enabledToolIds) {
+    await toggleTool(getToolNode(id));
   }
 
   // Toggle first, middle, and last tools to ensure that toolbox tabs are
   // inserted in order
-  let firstTool = toolNodes[0];
-  let middleTool = toolNodes[(toolNodes.length / 2) | 0];
-  let lastTool = toolNodes[toolNodes.length - 1];
+  let firstToolId = toolNodeIds[0];
+  let middleToolId = toolNodeIds[(toolNodeIds.length / 2) | 0];
+  let lastToolId = toolNodeIds[toolNodeIds.length - 1];
 
-  await toggleTool(firstTool);
-  await toggleTool(firstTool);
-  await toggleTool(middleTool);
-  await toggleTool(middleTool);
-  await toggleTool(lastTool);
-  await toggleTool(lastTool);
+  await toggleTool(getToolNode(firstToolId));
+  await toggleTool(getToolNode(firstToolId));
+  await toggleTool(getToolNode(middleToolId));
+  await toggleTool(getToolNode(middleToolId));
+  await toggleTool(getToolNode(lastToolId));
+  await toggleTool(getToolNode(lastToolId));
 }
 
+/**
+ * Toggle tool node checkbox. Note: because toggling the checkbox will result in
+ * re-rendering of the tool list, we must re-query the checkboxes every time.
+ */
 async function toggleTool(node) {
   let deferred = defer();
 
diff --git a/devtools/client/framework/test/browser_toolbox_options_multiple_tabs.js b/devtools/client/framework/test/browser_toolbox_options_multiple_tabs.js
new file mode 100644
index 000000000000..49a399e060b9
--- /dev/null
+++ b/devtools/client/framework/test/browser_toolbox_options_multiple_tabs.js
@@ -0,0 +1,112 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const URL = "data:text/html;charset=utf8,test for dynamically registering " +
+            "and unregistering tools across multiple tabs";
+
+let tab1, tab2, modifiedPref;
+
+add_task(async function() {
+  tab1 = await openToolboxOptionsInNewTab();
+  tab2 = await openToolboxOptionsInNewTab();
+
+  await testToggleTools();
+  await cleanup();
+});
+
+async function openToolboxOptionsInNewTab() {
+  const tab = await addTab(URL);
+  const target = TargetFactory.forTab(tab);
+  const toolbox = await gDevTools.showToolbox(target);
+  const doc = toolbox.doc;
+  const panel = await toolbox.selectTool("options");
+  const { id } = panel.panelDoc.querySelector(
+    "#default-tools-box input[type=checkbox]:not([data-unsupported]):not([checked])");
+
+  return {
+    tab,
+    toolbox,
+    doc,
+    panelWin: panel.panelWin,
+    // This is a getter becuse toolbox tools list gets re-setup every time there
+    // is a tool-registered or tool-undregistered event.
+    get checkbox() {
+      return panel.panelDoc.getElementById(id);
+    }
+  };
+}
+
+async function testToggleTools() {
+  is(tab1.checkbox.id, tab2.checkbox.id, "Default tool box should be in sync.");
+
+  const toolId = tab1.checkbox.id;
+  const testTool = gDevTools.getDefaultTools().find(tool => tool.id === toolId);
+  // Store modified pref names so that they can be cleared on error.
+  modifiedPref = testTool.visibilityswitch;
+
+  info(`Registering tool ${toolId} in the first tab.`);
+  await toggleTool(tab1, toolId);
+
+  info(`Unregistering tool ${toolId} in the first tab.`);
+  await toggleTool(tab1, toolId);
+
+  info(`Registering tool ${toolId} in the second tab.`);
+  await toggleTool(tab2, toolId);
+
+  info(`Unregistering tool ${toolId} in the second tab.`);
+  await toggleTool(tab2, toolId);
+
+  info(`Registering tool ${toolId} in the first tab.`);
+  await toggleTool(tab1, toolId);
+
+  info(`Unregistering tool ${toolId} in the second tab.`);
+  await toggleTool(tab2, toolId);
+}
+
+async function toggleTool({ doc, panelWin, checkbox, tab }, toolId) {
+  const prevChecked = checkbox.checked;
+
+  (prevChecked ? checkRegistered : checkUnregistered)(toolId);
+
+  const onToggleTool = gDevTools.once(
+    `tool-${prevChecked ? "unregistered" : "registered"}`);
+  EventUtils.sendMouseEvent({ type: "click" }, checkbox, panelWin);
+  const id = await onToggleTool;
+
+  is(id, toolId, `Correct event for ${toolId} was fired`);
+  // await new Promise(resolve => setTimeout(resolve, 60000));
+  (prevChecked ? checkUnregistered : checkRegistered)(toolId);
+}
+
+async function checkUnregistered(toolId) {
+  ok(!tab1.doc.getElementById("toolbox-tab-" + toolId),
+    `Tab for unregistered tool ${toolId} is not present in first toolbox`);
+  ok(!tab1.checkbox.checked,
+    `Checkbox for unregistered tool ${toolId} is not checked in first toolbox`);
+  ok(!tab2.doc.getElementById("toolbox-tab-" + toolId),
+    `Tab for unregistered tool ${toolId} is not present in second toolbox`);
+  ok(!tab2.checkbox.checked,
+    `Checkbox for unregistered tool ${toolId} is not checked in second toolbox`);
+}
+
+function checkRegistered(toolId) {
+  ok(tab1.doc.getElementById("toolbox-tab-" + toolId),
+    `Tab for registered tool ${toolId} is present in first toolbox`);
+  ok(tab1.checkbox.checked,
+    `Checkbox for registered tool ${toolId} is checked in first toolbox`);
+  ok(tab2.doc.getElementById("toolbox-tab-" + toolId),
+    `Tab for registered tool ${toolId} is present in second toolbox`);
+  ok(tab2.checkbox.checked,
+    `Checkbox for registered tool ${toolId} is checked in second toolbox`);
+}
+
+async function cleanup() {
+  await tab1.toolbox.destroy();
+  await tab2.toolbox.destroy();
+  gBrowser.removeCurrentTab();
+  gBrowser.removeCurrentTab();
+  Services.prefs.clearUserPref(modifiedPref);
+  tab1 = tab2 = modifiedPref = null;
+}
diff --git a/devtools/client/framework/toolbox-options.js b/devtools/client/framework/toolbox-options.js
index 5a4f78000e3d..c3cbabed24b6 100644
--- a/devtools/client/framework/toolbox-options.js
+++ b/devtools/client/framework/toolbox-options.js
@@ -61,11 +61,10 @@ function OptionsPanel(iframeWindow, toolbox) {
   this.toolbox = toolbox;
   this.isReady = false;
 
+  this.setupToolsList = this.setupToolsList.bind(this);
   this._prefChanged = this._prefChanged.bind(this);
   this._themeRegistered = this._themeRegistered.bind(this);
   this._themeUnregistered = this._themeUnregistered.bind(this);
-  this._webExtensionRegistered = this._webExtensionRegistered.bind(this);
-  this._webExtensionUnregistered = this._webExtensionUnregistered.bind(this);
   this._disableJSClicked = this._disableJSClicked.bind(this);
 
   this.disableJSNode = this.panelDoc.getElementById("devtools-disable-javascript");
@@ -106,8 +105,14 @@ OptionsPanel.prototype = {
     gDevTools.on("theme-registered", this._themeRegistered);
     gDevTools.on("theme-unregistered", this._themeUnregistered);
 
-    this.toolbox.on("webextension-registered", this._webExtensionRegistered);
-    this.toolbox.on("webextension-unregistered", this._webExtensionUnregistered);
+    // Refresh the tools list when a new tool or webextension has been
+    // registered to the toolbox.
+    this.toolbox.on("tool-registered", this.setupToolsList);
+    this.toolbox.on("webextension-registered", this.setupToolsList);
+    // Refresh the tools list when a new tool or webextension has been
+    // unregistered from the toolbox.
+    this.toolbox.on("tool-unregistered", this.setupToolsList);
+    this.toolbox.on("webextension-unregistered", this.setupToolsList);
   },
 
   _removeListeners: function() {
@@ -116,8 +121,10 @@ OptionsPanel.prototype = {
     Services.prefs.removeObserver("devtools.source-map.client-service.enabled",
                                   this._prefChanged);
 
-    this.toolbox.off("webextension-registered", this._webExtensionRegistered);
-    this.toolbox.off("webextension-unregistered", this._webExtensionUnregistered);
+    this.toolbox.off("tool-registered", this.setupToolsList);
+    this.toolbox.off("tool-unregistered", this.setupToolsList);
+    this.toolbox.off("webextension-registered", this.setupToolsList);
+    this.toolbox.off("webextension-unregistered", this.setupToolsList);
 
     gDevTools.off("theme-registered", this._themeRegistered);
     gDevTools.off("theme-unregistered", this._themeUnregistered);
@@ -148,18 +155,6 @@ OptionsPanel.prototype = {
     }
   },
 
-  _webExtensionRegistered: function(extensionUUID) {
-    // Refresh the tools list when a new webextension has been registered
-    // to the toolbox.
-    this.setupToolsList();
-  },
-
-  _webExtensionUnregistered: function(extensionUUID) {
-    // Refresh the tools list when a new webextension has been unregistered
-    // from the toolbox.
-    this.setupToolsList();
-  },
-
   async setupToolbarButtonsList() {
     // Ensure the toolbox is open, and the buttons are all set up.
     await this.toolbox.isOpen;
diff --git a/dom/file/ipc/IPCBlobInputStream.cpp b/dom/file/ipc/IPCBlobInputStream.cpp
index d408281b9737..a6c4e75e8fc9 100644
--- a/dom/file/ipc/IPCBlobInputStream.cpp
+++ b/dom/file/ipc/IPCBlobInputStream.cpp
@@ -380,8 +380,20 @@ IPCBlobInputStream::AsyncWait(nsIInputStreamCallback* aCallback,
 
   // We have the remote inputStream, let's check if we can execute the callback.
   case eRunning: {
-    MutexAutoLock lock(mMutex);
-    return MaybeExecuteInputStreamCallback(aCallback, aEventTarget, lock);
+    {
+      MutexAutoLock lock(mMutex);
+      mInputStreamCallback = aCallback;
+      mInputStreamCallbackEventTarget = aEventTarget;
+    }
+
+    nsresult rv = EnsureAsyncRemoteStream();
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+
+    MOZ_ASSERT(mAsyncRemoteStream);
+    return mAsyncRemoteStream->AsyncWait(aCallback ? this : nullptr,
+                                         0, 0, aEventTarget);
   }
 
   // Stream is closed.
@@ -435,64 +447,28 @@ IPCBlobInputStream::StreamReady(already_AddRefed<nsIInputStream> aInputStream)
                                           this);
   }
 
+  nsCOMPtr<nsIInputStreamCallback> inputStreamCallback = this;
+  nsCOMPtr<nsIEventTarget> inputStreamCallbackEventTarget;
   {
     MutexAutoLock lock(mMutex);
-
-    nsCOMPtr<nsIInputStreamCallback> inputStreamCallback;
-    inputStreamCallback.swap(mInputStreamCallback);
-
-    nsCOMPtr<nsIEventTarget> inputStreamCallbackEventTarget;
-    inputStreamCallbackEventTarget.swap(mInputStreamCallbackEventTarget);
-
-    if (inputStreamCallback) {
-      MaybeExecuteInputStreamCallback(inputStreamCallback,
-                                      inputStreamCallbackEventTarget,
-                                      lock);
+    inputStreamCallbackEventTarget = mInputStreamCallbackEventTarget;
+    if (!mInputStreamCallback) {
+      inputStreamCallback = nullptr;
     }
   }
-}
 
-nsresult
-IPCBlobInputStream::MaybeExecuteInputStreamCallback(nsIInputStreamCallback* aCallback,
-                                                    nsIEventTarget* aCallbackEventTarget,
-                                                    const MutexAutoLock& aProofOfLock)
-{
-  MOZ_ASSERT(mState == eRunning);
-  MOZ_ASSERT(mRemoteStream || mAsyncRemoteStream);
-
-  // If the callback has been already set, we return an error.
-  if (mInputStreamCallback && aCallback) {
-    return NS_ERROR_FAILURE;
-  }
-
-  bool hadCallback = !!mInputStreamCallback;
-
-  mInputStreamCallback = aCallback;
-  mInputStreamCallbackEventTarget = aCallbackEventTarget;
-
-  nsCOMPtr<nsIInputStreamCallback> callback = this;
-
-  if (!mInputStreamCallback) {
-    if (!hadCallback) {
-      // Nothing was pending.
-      return NS_OK;
+  if (inputStreamCallback) {
+    nsresult rv = EnsureAsyncRemoteStream();
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return;
     }
 
-    // Let's set a null callback in order to abort the current operation.
-    callback = nullptr;
+    MOZ_ASSERT(mAsyncRemoteStream);
+
+    rv = mAsyncRemoteStream->AsyncWait(inputStreamCallback, 0, 0,
+                                       inputStreamCallbackEventTarget);
+    Unused << NS_WARN_IF(NS_FAILED(rv));
   }
-
-  // We don't need to be locked anymore.
-  MutexAutoUnlock unlock(mMutex);
-
-  nsresult rv = EnsureAsyncRemoteStream();
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    return rv;
-  }
-
-  MOZ_ASSERT(mAsyncRemoteStream);
-
-  return mAsyncRemoteStream->AsyncWait(callback, 0, 0, aCallbackEventTarget);
 }
 
 void
diff --git a/dom/file/ipc/IPCBlobInputStream.h b/dom/file/ipc/IPCBlobInputStream.h
index 081a96d76a87..61c2fd10bb66 100644
--- a/dom/file/ipc/IPCBlobInputStream.h
+++ b/dom/file/ipc/IPCBlobInputStream.h
@@ -44,11 +44,6 @@ public:
 private:
   ~IPCBlobInputStream();
 
-  nsresult
-  MaybeExecuteInputStreamCallback(nsIInputStreamCallback* aCallback,
-                                  nsIEventTarget* aEventTarget,
-                                  const MutexAutoLock& aProofOfLock);
-
   nsresult
   EnsureAsyncRemoteStream();
 
diff --git a/dom/ipc/PContent.ipdl b/dom/ipc/PContent.ipdl
index 962ac1ef378d..f06409670f51 100644
--- a/dom/ipc/PContent.ipdl
+++ b/dom/ipc/PContent.ipdl
@@ -117,7 +117,7 @@ struct FontListEntry {
     nsString  familyName;
     nsString  faceName;
     nsCString filepath;
-    uint16_t  weight;
+    float     weight;
     int16_t   stretch;
     uint8_t   italic;
     uint8_t   index;
diff --git a/dom/mathml/nsMathMLElement.cpp b/dom/mathml/nsMathMLElement.cpp
index 01200ff9a833..0500bc05f420 100644
--- a/dom/mathml/nsMathMLElement.cpp
+++ b/dom/mathml/nsMathMLElement.cpp
@@ -8,6 +8,7 @@
 #include "nsMathMLElement.h"
 #include "base/compiler_specific.h"
 #include "mozilla/ArrayUtils.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "nsGkAtoms.h"
 #include "nsITableCellLayout.h" // for MAX_COLSPAN / MAX_ROWSPAN
 #include "nsCRT.h"
@@ -726,10 +727,10 @@ nsMathMLElement::MapMathMLAttributesInto(const nsMappedAttributes* aAttributes,
       str.CompressWhitespace();
       if (str.EqualsASCII("normal")) {
         aData->SetKeywordValue(eCSSProperty_font_weight,
-                               NS_FONT_WEIGHT_NORMAL);
+                               FontWeight::Normal().ToFloat());
       } else if (str.EqualsASCII("bold")) {
         aData->SetKeywordValue(eCSSProperty_font_weight,
-                               NS_FONT_WEIGHT_BOLD);
+                               FontWeight::Bold().ToFloat());
       }
     }
   }
diff --git a/dom/media/MediaData.h b/dom/media/MediaData.h
index 31bdf729cbc3..68dbcb3d1d02 100644
--- a/dom/media/MediaData.h
+++ b/dom/media/MediaData.h
@@ -645,11 +645,11 @@ public:
 
   // Set size of buffer, allocating memory as required.
   // If size is increased, new buffer area is filled with 0.
-  bool SetSize(size_t aSize);
+  MOZ_MUST_USE bool SetSize(size_t aSize);
   // Add aData at the beginning of buffer.
-  bool Prepend(const uint8_t* aData, size_t aSize);
+  MOZ_MUST_USE bool Prepend(const uint8_t* aData, size_t aSize);
   // Replace current content with aData.
-  bool Replace(const uint8_t* aData, size_t aSize);
+  MOZ_MUST_USE bool Replace(const uint8_t* aData, size_t aSize);
   // Clear the memory buffer. Will set target mData and mSize to 0.
   void Clear();
   // Remove aSize bytes from the front of the sample.
@@ -658,7 +658,7 @@ public:
 private:
   friend class MediaRawData;
   explicit MediaRawDataWriter(MediaRawData* aMediaRawData);
-  bool EnsureSize(size_t aSize);
+  MOZ_MUST_USE bool EnsureSize(size_t aSize);
   MediaRawData* mTarget;
 };
 
diff --git a/dom/script/ScriptLoader.cpp b/dom/script/ScriptLoader.cpp
index fe4005890873..73052aee8894 100644
--- a/dom/script/ScriptLoader.cpp
+++ b/dom/script/ScriptLoader.cpp
@@ -3054,6 +3054,22 @@ ScriptLoader::NumberOfProcessors()
   return mNumberOfProcessors;
 }
 
+static bool
+IsInternalURIScheme(nsIURI* uri)
+{
+  bool isWebExt;
+  if (NS_SUCCEEDED(uri->SchemeIs("moz-extension", &isWebExt)) && isWebExt) {
+    return true;
+  }
+
+  bool isResource;
+  if (NS_SUCCEEDED(uri->SchemeIs("resource", &isResource)) && isResource) {
+    return true;
+  }
+
+  return false;
+}
+
 nsresult
 ScriptLoader::PrepareLoadedRequest(ScriptLoadRequest* aRequest,
                                    nsIIncrementalStreamLoader* aLoader,
@@ -3142,10 +3158,9 @@ ScriptLoader::PrepareLoadedRequest(ScriptLoadRequest* aRequest,
     rv = channel->GetOriginalURI(getter_AddRefs(uri));
     NS_ENSURE_SUCCESS(rv, rv);
 
-    // Fixup moz-extension URIs, because the channel URI points to file:,
-    // which won't be allowed to load.
-    bool isWebExt = false;
-    if (uri && NS_SUCCEEDED(uri->SchemeIs("moz-extension", &isWebExt)) && isWebExt) {
+    // Fixup moz-extension: and resource: URIs, because the channel URI will
+    // point to file:, which won't be allowed to load.
+    if (uri && IsInternalURIScheme(uri)) {
       request->mBaseURL = uri;
     } else {
       channel->GetURI(getter_AddRefs(request->mBaseURL));
diff --git a/dom/security/test/general/file_same_site_cookies_redirect.sjs b/dom/security/test/general/file_same_site_cookies_redirect.sjs
new file mode 100644
index 000000000000..2337df4824fd
--- /dev/null
+++ b/dom/security/test/general/file_same_site_cookies_redirect.sjs
@@ -0,0 +1,61 @@
+// Custom *.sjs file specifically for the needs of Bug 1453814
+
+// small red image
+const IMG_BYTES = atob(
+  "iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12" +
+  "P4//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg==");
+
+const FRAME = `
+  <!DOCTYPE html>
+  <html>
+  <head>
+    <title>Bug 1453814 - Do not allow same-site cookies for cross origin redirect</title>
+  </head>
+  <body>
+    <script type="application/javascript">
+      let cookie = document.cookie;
+      // now reset the cookie for the next test
+      document.cookie = "myKey=;" + "expires=Thu, 01 Jan 1970 00:00:00 GMT";
+      window.parent.postMessage({result: cookie}, 'http://mochi.test:8888');
+    </script>
+  </body>
+  </html>`;
+
+const SAME_ORIGIN = "http://mochi.test:8888/"
+const CROSS_ORIGIN = "http://example.com/";
+const PATH = "tests/dom/security/test/general/file_same_site_cookies_redirect.sjs";
+
+function handleRequest(request, response)
+{
+  // avoid confusing cache behaviors
+  response.setHeader("Cache-Control", "no-cache", false);
+
+  if (request.queryString === "setSameSiteCookie") {
+    response.setHeader("Set-Cookie", "myKey=strictSameSiteCookie; samesite=strict", true);
+    response.setHeader("Content-Type", "image/png");
+    response.write(IMG_BYTES);
+    return;
+  }
+
+  if (request.queryString === "sameToCrossRedirect") {
+    let URL = CROSS_ORIGIN + PATH + "?loadFrame";
+    response.setStatusLine("1.1", 302, "Found");
+    response.setHeader("Location", URL, false);
+    return;
+  }
+
+  if (request.queryString === "crossToSameRedirect") {
+    let URL = SAME_ORIGIN + PATH + "?loadFrame";
+    response.setStatusLine("1.1", 302, "Found");
+    response.setHeader("Location", URL, false);
+    return;
+  }
+
+  if (request.queryString === "loadFrame") {
+    response.write(FRAME);
+    return;
+  }
+
+  // we should never get here, but just in case return something unexpected
+  response.write("D'oh");
+}
diff --git a/dom/security/test/general/mochitest.ini b/dom/security/test/general/mochitest.ini
index 4d1afac02af7..64dd20138177 100644
--- a/dom/security/test/general/mochitest.ini
+++ b/dom/security/test/general/mochitest.ini
@@ -12,6 +12,7 @@ support-files =
   file_same_site_cookies_toplevel_nav.sjs
   file_same_site_cookies_cross_origin_context.sjs
   file_same_site_cookies_from_script.sjs
+  file_same_site_cookies_redirect.sjs
 
 [test_contentpolicytype_targeted_link_iframe.html]
 [test_nosniff.html]
@@ -29,3 +30,4 @@ skip-if = toolkit == 'android'
 [test_same_site_cookies_toplevel_nav.html]
 [test_same_site_cookies_cross_origin_context.html]
 [test_same_site_cookies_from_script.html]
+[test_same_site_cookies_redirect.html]
diff --git a/dom/security/test/general/test_same_site_cookies_redirect.html b/dom/security/test/general/test_same_site_cookies_redirect.html
new file mode 100644
index 000000000000..4fdc8936a39e
--- /dev/null
+++ b/dom/security/test/general/test_same_site_cookies_redirect.html
@@ -0,0 +1,83 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>Bug 1453814 - Do not allow same-site cookies for cross origin redirect</title>
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<img id="cookieImage">
+<iframe id="testframe"></iframe>
+
+<script class="testbody" type="text/javascript">
+
+/*
+ * Description of the test:
+ * 1) We load an image from http://mochi.test which set a same site cookie
+ * 2) We then load an iframe that redirects
+ *    (a) from same-origin to cross-origin
+ *    (b) from cross-origin to same-origin
+ * 3) We observe that in both cases same-site cookies should not be send
+ */
+
+SimpleTest.waitForExplicitFinish();
+
+const SAME_ORIGIN = "http://mochi.test:8888/"
+const CROSS_ORIGIN = "http://example.com/";
+const PATH = "tests/dom/security/test/general/file_same_site_cookies_redirect.sjs";
+
+let curTest = 0;
+
+var tests = [
+  {
+    description: "same-site cookie, redirect same-site to cross-site",
+    imgSRC: SAME_ORIGIN + PATH + "?setSameSiteCookie",
+    frameSRC: SAME_ORIGIN + PATH + "?sameToCrossRedirect",
+    result: "", // no cookie should be set
+  },
+  {
+    description: "same-site cookie, redirect cross-site to same-site",
+    imgSRC: SAME_ORIGIN + PATH + "?setSameSiteCookie",
+    frameSRC: CROSS_ORIGIN + PATH + "?crossToSameRedirect",
+    result: "", // no cookie should be set
+  },
+];
+
+window.addEventListener("message", receiveMessage);
+function receiveMessage(event) {
+  is(event.data.result, tests[curTest].result, tests[curTest].description);
+  curTest += 1;
+
+  // // lets see if we ran all the tests
+  if (curTest == tests.length) {
+    window.removeEventListener("message", receiveMessage);
+    SimpleTest.finish();
+    return;
+  }
+  // otherwise it's time to run the next test
+  setCookieAndInitTest();
+}
+
+function setupQueryResultAndRunTest() {
+  let testframe = document.getElementById("testframe");
+  testframe.src = tests[curTest].frameSRC;
+}
+
+function setCookieAndInitTest() {
+  var cookieImage = document.getElementById("cookieImage");
+  cookieImage.onload = function() {
+    ok(true, "trying to set cookie for test (" + tests[curTest].description + ")");
+    setupQueryResultAndRunTest();
+  }
+  cookieImage.onerror = function() {
+    ok(false, "could not load image for test (" + tests[curTest].description + ")");
+  }
+  cookieImage.src =  tests[curTest].imgSRC;
+}
+
+// fire up the test
+setCookieAndInitTest();
+
+</script>
+</body>
+</html>
diff --git a/dom/workers/RuntimeService.cpp b/dom/workers/RuntimeService.cpp
index 1aaa6b7a14e1..2f5f933b4a67 100644
--- a/dom/workers/RuntimeService.cpp
+++ b/dom/workers/RuntimeService.cpp
@@ -294,6 +294,9 @@ LoadContextOptions(const char* aPrefName, void* /* aClosure */)
                 .setWasm(GetWorkerPref<bool>(NS_LITERAL_CSTRING("wasm")))
                 .setWasmBaseline(GetWorkerPref<bool>(NS_LITERAL_CSTRING("wasm_baselinejit")))
                 .setWasmIon(GetWorkerPref<bool>(NS_LITERAL_CSTRING("wasm_ionjit")))
+#ifdef ENABLE_WASM_GC
+                .setWasmGc(GetWorkerPref<bool>(NS_LITERAL_CSTRING("wasm_gc")))
+#endif
                 .setThrowOnAsmJSValidationFailure(GetWorkerPref<bool>(
                       NS_LITERAL_CSTRING("throw_on_asmjs_validation_failure")))
                 .setBaseline(GetWorkerPref<bool>(NS_LITERAL_CSTRING("baselinejit")))
diff --git a/dom/workers/moz.build b/dom/workers/moz.build
index 1f23ef4f5f59..ccaaf27a6da1 100644
--- a/dom/workers/moz.build
+++ b/dom/workers/moz.build
@@ -98,3 +98,6 @@ BROWSER_CHROME_MANIFESTS += ['test/browser.ini']
 
 if CONFIG['CC_TYPE'] in ('clang', 'gcc'):
     CXXFLAGS += ['-Wno-error=shadow']
+
+if CONFIG['NIGHTLY_BUILD']:
+    DEFINES['ENABLE_WASM_GC'] = True
diff --git a/gfx/2d/NativeFontResourceDWrite.cpp b/gfx/2d/NativeFontResourceDWrite.cpp
index 03a6debd233b..c89d7efcda0b 100644
--- a/gfx/2d/NativeFontResourceDWrite.cpp
+++ b/gfx/2d/NativeFontResourceDWrite.cpp
@@ -12,6 +12,7 @@
 #include "Logging.h"
 #include "mozilla/RefPtr.h"
 #include "mozilla/StaticMutex.h"
+#include "nsTArray.h"
 
 namespace mozilla {
 namespace gfx {
@@ -84,6 +85,8 @@ private:
 class DWriteFontFileStream final : public IDWriteFontFileStream
 {
 public:
+  explicit DWriteFontFileStream(uint64_t aFontFileKey);
+
   /**
     * Used by the FontFileLoader to create a new font stream,
     * this font stream is created from data in memory. The memory
@@ -92,7 +95,7 @@ public:
     *
     * @param aData Font data
     */
-  DWriteFontFileStream(uint8_t *aData, uint32_t aSize, uint64_t aFontFileKey);
+  bool Initialize(uint8_t *aData, uint32_t aSize);
 
   // IUnknown interface
   IFACEMETHOD(QueryInterface)(IID const& iid, OUT void** ppObject)
@@ -135,7 +138,7 @@ public:
   virtual HRESULT STDMETHODCALLTYPE GetLastWriteTime(OUT UINT64* lastWriteTime);
 
 private:
-  std::vector<uint8_t> mData;
+  nsTArray<uint8_t> mData;
   Atomic<uint32_t> mRefCnt;
   uint64_t mFontFileKey;
 
@@ -166,13 +169,10 @@ DWriteFontFileLoader::CreateStreamFromKey(const void *fontFileReferenceKey,
   return S_OK;
 }
 
-DWriteFontFileStream::DWriteFontFileStream(uint8_t *aData, uint32_t aSize,
-                                           uint64_t aFontFileKey)
+DWriteFontFileStream::DWriteFontFileStream(uint64_t aFontFileKey)
   : mRefCnt(0)
   , mFontFileKey(aFontFileKey)
 {
-  mData.resize(aSize);
-  memcpy(&mData.front(), aData, aSize);
 }
 
 DWriteFontFileStream::~DWriteFontFileStream()
@@ -181,10 +181,20 @@ DWriteFontFileStream::~DWriteFontFileStream()
   sFontFileStreams.erase(mFontFileKey);
 }
 
+bool
+DWriteFontFileStream::Initialize(uint8_t *aData, uint32_t aSize)
+{
+  if (!mData.SetLength(aSize, fallible)) {
+    return false;
+  }
+  memcpy(mData.Elements(), aData, aSize);
+  return true;
+}
+
 HRESULT STDMETHODCALLTYPE
 DWriteFontFileStream::GetFileSize(UINT64 *fileSize)
 {
-  *fileSize = mData.size();
+  *fileSize = mData.Length();
   return S_OK;
 }
 
@@ -201,7 +211,7 @@ DWriteFontFileStream::ReadFileFragment(const void **fragmentStart,
                                        void **fragmentContext)
 {
   // We are required to do bounds checking.
-  if (fileOffset + fragmentSize > mData.size()) {
+  if (fileOffset + fragmentSize > mData.Length()) {
     return E_FAIL;
   }
 
@@ -232,8 +242,12 @@ NativeFontResourceDWrite::Create(uint8_t *aFontData, uint32_t aDataLength,
 
   sFontFileStreamsMutex.Lock();
   uint64_t fontFileKey = sNextFontFileKey++;
-  RefPtr<IDWriteFontFileStream> ffsRef =
-    new DWriteFontFileStream(aFontData, aDataLength, fontFileKey);
+  RefPtr<DWriteFontFileStream> ffsRef = new DWriteFontFileStream(fontFileKey);
+  if (!ffsRef->Initialize(aFontData, aDataLength)) {
+    sFontFileStreamsMutex.Unlock();
+    gfxWarning() << "Failed to create DWriteFontFileStream.";
+    return nullptr;
+  }
   sFontFileStreams[fontFileKey] = ffsRef;
   sFontFileStreamsMutex.Unlock();
 
diff --git a/gfx/2d/NativeFontResourceFontconfig.cpp b/gfx/2d/NativeFontResourceFontconfig.cpp
index 3dc1bc9263ad..e0665480e203 100644
--- a/gfx/2d/NativeFontResourceFontconfig.cpp
+++ b/gfx/2d/NativeFontResourceFontconfig.cpp
@@ -32,7 +32,10 @@ NativeFontResourceFontconfig::Create(uint8_t *aFontData, uint32_t aDataLength, F
   if (!aFontData || !aDataLength) {
     return nullptr;
   }
-  UniquePtr<uint8_t[]> fontData(new uint8_t[aDataLength]);
+  UniquePtr<uint8_t[]> fontData(new (fallible) uint8_t[aDataLength]);
+  if (!fontData) {
+    return nullptr;
+  }
   memcpy(fontData.get(), aFontData, aDataLength);
 
   FT_Face face = Factory::NewFTFaceFromData(aFTLibrary, fontData.get(), aDataLength, 0);
diff --git a/gfx/2d/ScaledFontDWrite.cpp b/gfx/2d/ScaledFontDWrite.cpp
index a63cf747fef5..8dfb01dca0e8 100644
--- a/gfx/2d/ScaledFontDWrite.cpp
+++ b/gfx/2d/ScaledFontDWrite.cpp
@@ -137,7 +137,7 @@ ScaledFontDWrite::ScaledFontDWrite(IDWriteFontFace *aFontFace,
     , mContrast(aContrast)
 {
   if (aStyle) {
-    mStyle = SkFontStyle(aStyle->weight,
+    mStyle = SkFontStyle(aStyle->weight.ToIntRounded(),
                          DWriteFontStretchFromStretch(aStyle->stretch),
                          aStyle->style == NS_FONT_STYLE_NORMAL ?
                          SkFontStyle::kUpright_Slant : SkFontStyle::kItalic_Slant);
diff --git a/gfx/layers/SourceSurfaceSharedData.h b/gfx/layers/SourceSurfaceSharedData.h
index 549ea205b9d5..5ce1302be4da 100644
--- a/gfx/layers/SourceSurfaceSharedData.h
+++ b/gfx/layers/SourceSurfaceSharedData.h
@@ -82,17 +82,6 @@ public:
   void Unmap() override
   { }
 
-  bool AddConsumer()
-  {
-    return ++mConsumers == 1;
-  }
-
-  bool RemoveConsumer()
-  {
-    MOZ_ASSERT(mConsumers > 0);
-    return --mConsumers == 0;
-  }
-
 private:
   size_t GetDataLength() const
   {
@@ -105,7 +94,6 @@ private:
   }
 
   int32_t mStride;
-  uint32_t mConsumers;
   IntSize mSize;
   RefPtr<SharedMemoryBasic> mBuf;
   SurfaceFormat mFormat;
diff --git a/gfx/layers/ipc/SharedSurfacesParent.cpp b/gfx/layers/ipc/SharedSurfacesParent.cpp
index e2f2ba8dcc08..6bc512bffedc 100644
--- a/gfx/layers/ipc/SharedSurfacesParent.cpp
+++ b/gfx/layers/ipc/SharedSurfacesParent.cpp
@@ -54,44 +54,22 @@ SharedSurfacesParent::Get(const wr::ExternalImageId& aId)
   return surface.forget();
 }
 
-/* static */ already_AddRefed<DataSourceSurface>
-SharedSurfacesParent::Acquire(const wr::ExternalImageId& aId)
-{
-  MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
-  if (!sInstance) {
-    return nullptr;
-  }
-
-  RefPtr<SourceSurfaceSharedDataWrapper> surface;
-  sInstance->mSurfaces.Get(wr::AsUint64(aId), getter_AddRefs(surface));
-
-  if (surface) {
-    DebugOnly<bool> rv = surface->AddConsumer();
-    MOZ_ASSERT(!rv);
-  }
-  return surface.forget();
-}
-
-/* static */ bool
-SharedSurfacesParent::Release(const wr::ExternalImageId& aId)
+/* static */ void
+SharedSurfacesParent::Remove(const wr::ExternalImageId& aId)
 {
   //MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
   if (!sInstance) {
-    return false;
+    return;
   }
 
   uint64_t id = wr::AsUint64(aId);
   RefPtr<SourceSurfaceSharedDataWrapper> surface;
   sInstance->mSurfaces.Get(wr::AsUint64(aId), getter_AddRefs(surface));
   if (!surface) {
-    return false;
+    return;
   }
 
-  if (surface->RemoveConsumer()) {
-    sInstance->mSurfaces.Remove(id);
-  }
-
-  return true;
+  sInstance->mSurfaces.Remove(id);
 }
 
 /* static */ void
@@ -193,13 +171,5 @@ SharedSurfacesParent::Add(const wr::ExternalImageId& aId,
   sInstance->mSurfaces.Put(id, surface.forget());
 }
 
-/* static */ void
-SharedSurfacesParent::Remove(const wr::ExternalImageId& aId)
-{
-  //MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
-  DebugOnly<bool> rv = Release(aId);
-  MOZ_ASSERT(rv);
-}
-
 } // namespace layers
 } // namespace mozilla
diff --git a/gfx/layers/ipc/SharedSurfacesParent.h b/gfx/layers/ipc/SharedSurfacesParent.h
index 2b619f00fa9b..eaa3e2aa57f0 100644
--- a/gfx/layers/ipc/SharedSurfacesParent.h
+++ b/gfx/layers/ipc/SharedSurfacesParent.h
@@ -35,16 +35,9 @@ public:
   static void Initialize();
   static void Shutdown();
 
-  // Get without increasing the consumer count.
   static already_AddRefed<gfx::DataSourceSurface>
   Get(const wr::ExternalImageId& aId);
 
-  // Get but also increase the consumer count. Must call Release after finished.
-  static already_AddRefed<gfx::DataSourceSurface>
-  Acquire(const wr::ExternalImageId& aId);
-
-  static bool Release(const wr::ExternalImageId& aId);
-
   static void Add(const wr::ExternalImageId& aId,
                   const SurfaceDescriptorShared& aDesc,
                   base::ProcessId aPid);
diff --git a/gfx/src/FontPropertyTypes.h b/gfx/src/FontPropertyTypes.h
new file mode 100644
index 000000000000..2a1ef1e213f5
--- /dev/null
+++ b/gfx/src/FontPropertyTypes.h
@@ -0,0 +1,133 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* font specific types shared by both thebes and layout */
+
+#ifndef GFX_FONT_PROPERTY_TYPES_H
+#define GFX_FONT_PROPERTY_TYPES_H
+
+#include <cstdint>
+
+/*
+ * This file is separate from gfxFont.h so that layout can include it
+ * without bringing in gfxFont.h and everything it includes.
+ */
+
+namespace mozilla {
+
+/**
+ * A type that will in future encode a value as fixed point.
+ */
+class FontFixedPointValue
+{
+public:
+  // Ugh. We need a default constructor to allow this type to be used in the
+  // union in nsCSSValue.  Furthermore we need the default and copy
+  // constructors to be "trivial" (i.e. the compiler implemented defaults that
+  // do no initialization).
+  // Annoyingly it seems we can't make the default implementations constexpr
+  // (at least in clang).  We'd like to do that to allow Thin() et. al. below
+  // to also be constexpr. :/
+  FontFixedPointValue() = default;
+  FontFixedPointValue(const FontFixedPointValue& aOther) = default;
+
+  // Not currently encoded, but it will be in future
+  explicit FontFixedPointValue(int16_t aValue)
+    : mEncoded(aValue)
+  {}
+
+  explicit FontFixedPointValue(int32_t aValue)
+    : mEncoded(aValue)
+  {}
+
+  explicit FontFixedPointValue(float aValue)
+    : mEncoded(int16_t(aValue))
+  {}
+
+  float ToFloat() const {
+    return float(mEncoded);
+  }
+
+  int16_t ToIntRounded() const {
+    return mEncoded;
+  }
+
+  bool operator==(const FontFixedPointValue& aOther) const {
+    return mEncoded == aOther.mEncoded;
+  }
+
+  bool operator!=(const FontFixedPointValue& aOther) const {
+    return mEncoded != aOther.mEncoded;
+  }
+
+  bool operator<(const FontFixedPointValue& aOther) const {
+    return mEncoded < aOther.mEncoded;
+  }
+
+  bool operator<=(const FontFixedPointValue& aOther) const {
+    return mEncoded <= aOther.mEncoded;
+  }
+
+  bool operator>=(const FontFixedPointValue& aOther) const {
+    return mEncoded >= aOther.mEncoded;
+  }
+
+  bool operator>(const FontFixedPointValue& aOther) const {
+    return mEncoded > aOther.mEncoded;
+  }
+
+  int16_t ForHash() const {
+    return mEncoded;
+  }
+
+protected:
+  int16_t mEncoded;
+};
+
+class FontWeight : public FontFixedPointValue
+{
+public:
+  // Ugh, to get union in nsCSSValue compiling
+  FontWeight() = default;
+  FontWeight(const FontWeight& aOther) = default;
+
+    // Not currently encoded, but it will be in future
+  explicit FontWeight(int16_t aValue)
+    : FontFixedPointValue(aValue)
+  {}
+
+  explicit FontWeight(int32_t aValue)
+    : FontFixedPointValue(aValue)
+  {}
+
+  explicit FontWeight(float aValue)
+    : FontFixedPointValue(int16_t(aValue))
+  {}
+
+  bool operator==(const FontWeight& aOther) const
+  {
+    return mEncoded == aOther.mEncoded;
+  }
+
+  /// The "distance" between two font weights
+  float operator-(const FontWeight& aOther) const {
+    return this->ToFloat() - aOther.ToFloat();
+  }
+
+  static FontWeight Thin() {
+    return FontWeight{100};
+  }
+  static FontWeight Normal() {
+    return FontWeight{400};
+  }
+  static FontWeight Bold() {
+    return FontWeight{700};
+  }
+};
+
+} // namespace mozilla
+
+#endif // GFX_FONT_PROPERTY_TYPES_H
+
diff --git a/gfx/src/moz.build b/gfx/src/moz.build
index 893b185529fe..131af5c5cd5b 100644
--- a/gfx/src/moz.build
+++ b/gfx/src/moz.build
@@ -45,6 +45,7 @@ EXPORTS += [
 EXPORTS.mozilla += [
     'AppUnits.h',
     'ArrayView.h',
+    'FontPropertyTypes.h',
 ]
 
 EXPORTS.mozilla.gfx += [
diff --git a/gfx/src/nsFont.h b/gfx/src/nsFont.h
index 9a86b55d2a87..56b26b820c02 100644
--- a/gfx/src/nsFont.h
+++ b/gfx/src/nsFont.h
@@ -13,6 +13,7 @@
 #include "gfxFontConstants.h"           // for NS_FONT_KERNING_AUTO, etc
 #include "gfxFontFeatures.h"
 #include "gfxFontVariations.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/RefPtr.h"             // for RefPtr
 #include "nsColor.h"                    // for nsColor and NS_RGBA
 #include "nsCoord.h"                    // for nscoord
@@ -44,6 +45,7 @@ const uint8_t kGenericFont_fantasy      = 0x20;
 
 // Font structure.
 struct nsFont {
+  typedef mozilla::FontWeight FontWeight;
 
   // list of font families, either named or generic
   mozilla::FontFamilyList fontlist;
@@ -79,7 +81,7 @@ struct nsFont {
   nscolor fontSmoothingBackgroundColor = NS_RGBA(0,0,0,0);
 
   // The weight of the font; see gfxFontConstants.h.
-  uint16_t weight = NS_FONT_WEIGHT_NORMAL;
+  FontWeight weight = FontWeight::Normal();
 
   // The stretch of the font (the sum of various NS_FONT_STRETCH_*
   // constants; see gfxFontConstants.h).
diff --git a/gfx/thebes/gfxDWriteFontList.cpp b/gfx/thebes/gfxDWriteFontList.cpp
index 18a57463185a..9600d064fdda 100644
--- a/gfx/thebes/gfxDWriteFontList.cpp
+++ b/gfx/thebes/gfxDWriteFontList.cpp
@@ -4,6 +4,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "mozilla/ArrayUtils.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/intl/OSPreferences.h"
 
@@ -219,12 +220,12 @@ gfxDWriteFontFamily::FindStyleVariations(FontInfoData *aFontInfoData)
 
         if (LOG_FONTLIST_ENABLED()) {
             LOG_FONTLIST(("(fontlist) added (%s) to family (%s)"
-                 " with style: %s weight: %d stretch: %d psname: %s fullname: %s",
+                 " with style: %s weight: %g stretch: %d psname: %s fullname: %s",
                  NS_ConvertUTF16toUTF8(fe->Name()).get(),
                  NS_ConvertUTF16toUTF8(Name()).get(),
                  (fe->IsItalic()) ?
                   "italic" : (fe->IsOblique() ? "oblique" : "normal"),
-                 fe->Weight(), fe->Stretch(),
+                 fe->Weight().ToFloat(), fe->Stretch(),
                  NS_ConvertUTF16toUTF8(psname).get(),
                  NS_ConvertUTF16toUTF8(fullname).get()));
         }
@@ -956,7 +957,7 @@ gfxDWriteFontList::GetDefaultFontForPlatform(const gfxFontStyle *aStyle)
 
 gfxFontEntry *
 gfxDWriteFontList::LookupLocalFont(const nsAString& aFontName,
-                                   uint16_t aWeight,
+                                   FontWeight aWeight,
                                    int16_t aStretch,
                                    uint8_t aStyle)
 {
@@ -980,7 +981,7 @@ gfxDWriteFontList::LookupLocalFont(const nsAString& aFontName,
 
 gfxFontEntry *
 gfxDWriteFontList::MakePlatformFont(const nsAString& aFontName,
-                                    uint16_t aWeight,
+                                    FontWeight aWeight,
                                     int16_t aStretch,
                                     uint8_t aStyle,
                                     const uint8_t* aFontData,
@@ -1151,12 +1152,12 @@ gfxDWriteFontList::InitFontListForPlatform()
                 if (LOG_FONTLIST_ENABLED()) {
                     gfxFontEntry *fe = faces[i];
                     LOG_FONTLIST(("(fontlist) moved (%s) to family (%s)"
-                         " with style: %s weight: %d stretch: %d",
+                         " with style: %s weight: %g stretch: %d",
                          NS_ConvertUTF16toUTF8(fe->Name()).get(),
                          NS_ConvertUTF16toUTF8(gillSansMTFamily->Name()).get(),
                          (fe->IsItalic()) ?
                           "italic" : (fe->IsOblique() ? "oblique" : "normal"),
-                         fe->Weight(), fe->Stretch()));
+                         fe->Weight().ToFloat(), fe->Stretch()));
                 }
             }
 
diff --git a/gfx/thebes/gfxDWriteFontList.h b/gfx/thebes/gfxDWriteFontList.h
index bee3c4c7f1fb..de431ef0d8cf 100644
--- a/gfx/thebes/gfxDWriteFontList.h
+++ b/gfx/thebes/gfxDWriteFontList.h
@@ -6,6 +6,7 @@
 #ifndef GFX_DWRITEFONTLIST_H
 #define GFX_DWRITEFONTLIST_H
 
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/MemoryReporting.h"
 #include "gfxDWriteCommon.h"
 #include "dwrite_3.h"
@@ -46,6 +47,8 @@ class gfxDWriteFontEntry;
 class gfxDWriteFontFamily : public gfxFontFamily
 {
 public:
+    typedef mozilla::FontWeight FontWeight;
+
     /**
      * Constructs a new DWriteFont Family.
      *
@@ -119,7 +122,7 @@ public:
 
         weight = std::max<uint16_t>(100, weight);
         weight = std::min<uint16_t>(900, weight);
-        mWeight = weight;
+        mWeight = FontWeight(weight);
 
         mIsCJK = UNINITIALIZED_VALUE;
     }
@@ -137,7 +140,7 @@ public:
      */
     gfxDWriteFontEntry(const nsAString& aFaceName,
                               IDWriteFont *aFont,
-                              uint16_t aWeight,
+                              FontWeight aWeight,
                               int16_t aStretch,
                               uint8_t aStyle)
       : gfxFontEntry(aFaceName), mFont(aFont), mFontFile(nullptr),
@@ -164,7 +167,7 @@ public:
     gfxDWriteFontEntry(const nsAString& aFaceName,
                               IDWriteFontFile *aFontFile,
                               IDWriteFontFileStream *aFontFileStream,
-                              uint16_t aWeight,
+                              FontWeight aWeight,
                               int16_t aStretch,
                               uint8_t aStyle)
       : gfxFontEntry(aFaceName), mFont(nullptr),
@@ -401,12 +404,12 @@ public:
     gfxFontFamily* CreateFontFamily(const nsAString& aName) const override;
 
     virtual gfxFontEntry* LookupLocalFont(const nsAString& aFontName,
-                                          uint16_t aWeight,
+                                          FontWeight aWeight,
                                           int16_t aStretch,
                                           uint8_t aStyle);
 
     virtual gfxFontEntry* MakePlatformFont(const nsAString& aFontName,
-                                           uint16_t aWeight,
+                                           FontWeight aWeight,
                                            int16_t aStretch,
                                            uint8_t aStyle,
                                            const uint8_t* aFontData,
diff --git a/gfx/thebes/gfxDWriteFonts.cpp b/gfx/thebes/gfxDWriteFonts.cpp
index ef5dfbbd5da7..d3a453ff3116 100644
--- a/gfx/thebes/gfxDWriteFonts.cpp
+++ b/gfx/thebes/gfxDWriteFonts.cpp
@@ -11,6 +11,7 @@
 #include "gfxTextRun.h"
 
 #include "harfbuzz/hb.h"
+#include "mozilla/FontPropertyTypes.h"
 
 using namespace mozilla;
 using namespace mozilla::gfx;
@@ -135,7 +136,7 @@ bool
 gfxDWriteFont::GetFakeMetricsForArialBlack(DWRITE_FONT_METRICS *aFontMetrics)
 {
     gfxFontStyle style(mStyle);
-    style.weight = 700;
+    style.weight = FontWeight(700);
     bool needsBold;
 
     gfxFontEntry* fe =
@@ -156,7 +157,7 @@ void
 gfxDWriteFont::ComputeMetrics(AntialiasOption anAAOption)
 {
     DWRITE_FONT_METRICS fontMetrics;
-    if (!(mFontEntry->Weight() == 900 &&
+    if (!(mFontEntry->Weight() == FontWeight(900) &&
           !mFontEntry->IsUserFont() &&
           mFontEntry->Name().EqualsLiteral("Arial Black") &&
           GetFakeMetricsForArialBlack(&fontMetrics)))
diff --git a/gfx/thebes/gfxFT2FontList.cpp b/gfx/thebes/gfxFT2FontList.cpp
index fbf9e2b102c5..2756a12008a4 100644
--- a/gfx/thebes/gfxFT2FontList.cpp
+++ b/gfx/thebes/gfxFT2FontList.cpp
@@ -5,6 +5,7 @@
 
 #include "mozilla/ArrayUtils.h"
 #include "mozilla/Base64.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/MemoryReporting.h"
 
 #include "mozilla/dom/ContentChild.h"
@@ -256,7 +257,7 @@ FT2FontEntry::CreateFontInstance(const gfxFontStyle *aFontStyle, bool aNeedsBold
 /* static */
 FT2FontEntry*
 FT2FontEntry::CreateFontEntry(const nsAString& aFontName,
-                              uint16_t aWeight,
+                              FontWeight aWeight,
                               int16_t aStretch,
                               uint8_t aStyle,
                               const uint8_t* aFontData,
@@ -327,7 +328,9 @@ FT2FontEntry::CreateFontEntry(const FontListEntry& aFLE)
     FT2FontEntry *fe = new FT2FontEntry(aFLE.faceName());
     fe->mFilename = aFLE.filepath();
     fe->mFTFontIndex = aFLE.index();
-    fe->mWeight = aFLE.weight();
+    // The weight transported across IPC is a float, so we need to explicitly
+    // convert it back to a FontWeight.
+    fe->mWeight = FontWeight(aFLE.weight());
     fe->mStretch = aFLE.stretch();
     fe->mStyle = (aFLE.italic() ? NS_FONT_STYLE_ITALIC : NS_FONT_STYLE_NORMAL);
     return fe;
@@ -340,7 +343,7 @@ FTFaceIsItalic(FT_Face aFace)
     return !!(aFace->style_flags & FT_STYLE_FLAG_ITALIC);
 }
 
-static uint16_t
+static FontWeight
 FTFaceGetWeight(FT_Face aFace)
 {
     TT_OS2 *os2 = static_cast<TT_OS2*>(FT_Get_Sfnt_Table(aFace, ft_sfnt_os2));
@@ -368,7 +371,7 @@ FTFaceGetWeight(FT_Face aFace)
 
     NS_ASSERTION(result >= 100 && result <= 900, "Invalid weight in font!");
 
-    return result;
+    return FontWeight(result);
 }
 
 // Used to create the font entry for installed faces on the device,
@@ -660,10 +663,13 @@ FT2FontFamily::AddFacesToFontList(InfallibleTArray<FontListEntry>* aFontList)
         if (!fe) {
             continue;
         }
-        
+
+        // We convert the weight to a float purely for transport across IPC.
+        // Ideally we'd avoid doing that.
         aFontList->AppendElement(FontListEntry(Name(), fe->Name(),
                                                fe->mFilename,
-                                               fe->Weight(), fe->Stretch(),
+                                               fe->Weight().ToFloat(),
+                                               fe->Stretch(),
                                                fe->mStyle,
                                                fe->mFTFontIndex));
     }
@@ -985,7 +991,7 @@ AppendToFaceList(nsCString& aFaceList,
     aFaceList.Append(',');
     aFaceList.Append(aFontEntry->IsItalic() ? '1' : '0');
     aFaceList.Append(',');
-    aFaceList.AppendInt(aFontEntry->Weight());
+    aFaceList.AppendFloat(aFontEntry->Weight().ToFloat());
     aFaceList.Append(',');
     aFaceList.AppendInt(aFontEntry->Stretch());
     aFaceList.Append(',');
@@ -1144,11 +1150,11 @@ gfxFT2FontList::AddFaceToList(const nsCString& aEntryName, uint32_t aIndex,
         AppendToFaceList(aFaceList, name, fe);
         if (LOG_ENABLED()) {
             LOG(("(fontinit) added (%s) to family (%s)"
-                 " with style: %s weight: %d stretch: %d",
+                 " with style: %s weight: %g stretch: %d",
                  NS_ConvertUTF16toUTF8(fe->Name()).get(),
                  NS_ConvertUTF16toUTF8(family->Name()).get(),
                  fe->IsItalic() ? "italic" : "normal",
-                 fe->Weight(), fe->Stretch()));
+                 fe->Weight().ToFloat(), fe->Stretch()));
         }
     }
 }
@@ -1458,7 +1464,7 @@ gfxFT2FontList::InitFontListForPlatform()
 
 gfxFontEntry*
 gfxFT2FontList::LookupLocalFont(const nsAString& aFontName,
-                                uint16_t aWeight,
+                                FontWeight aWeight,
                                 int16_t aStretch,
                                 uint8_t aStyle)
 {
@@ -1540,7 +1546,7 @@ gfxFT2FontList::GetDefaultFontForPlatform(const gfxFontStyle* aStyle)
 
 gfxFontEntry*
 gfxFT2FontList::MakePlatformFont(const nsAString& aFontName,
-                                 uint16_t aWeight,
+                                 FontWeight aWeight,
                                  int16_t aStretch,
                                  uint8_t aStyle,
                                  const uint8_t* aFontData,
diff --git a/gfx/thebes/gfxFT2FontList.h b/gfx/thebes/gfxFT2FontList.h
index 1d5aae1b9b7e..4c9c2ffaa579 100644
--- a/gfx/thebes/gfxFT2FontList.h
+++ b/gfx/thebes/gfxFT2FontList.h
@@ -43,7 +43,7 @@ public:
     // create a font entry for a downloaded font
     static FT2FontEntry* 
     CreateFontEntry(const nsAString& aFontName,
-                    uint16_t aWeight,
+                    FontWeight aWeight,
                     int16_t aStretch,
                     uint8_t aStyle,
                     const uint8_t* aFontData,
@@ -122,12 +122,12 @@ public:
     virtual ~gfxFT2FontList();
 
     virtual gfxFontEntry* LookupLocalFont(const nsAString& aFontName,
-                                          uint16_t aWeight,
+                                          FontWeight aWeight,
                                           int16_t aStretch,
                                           uint8_t aStyle) override;
 
     virtual gfxFontEntry* MakePlatformFont(const nsAString& aFontName,
-                                           uint16_t aWeight,
+                                           FontWeight aWeight,
                                            int16_t aStretch,
                                            uint8_t aStyle,
                                            const uint8_t* aFontData,
diff --git a/gfx/thebes/gfxFcPlatformFontList.cpp b/gfx/thebes/gfxFcPlatformFontList.cpp
index 2936d36c0340..7caf5a904dca 100644
--- a/gfx/thebes/gfxFcPlatformFontList.cpp
+++ b/gfx/thebes/gfxFcPlatformFontList.cpp
@@ -160,40 +160,40 @@ GetFaceNames(FcPattern* aFont, const nsAString& aFamilyName,
     }
 }
 
-static uint16_t
+static FontWeight
 MapFcWeight(int aFcWeight)
 {
   if (aFcWeight <= (FC_WEIGHT_THIN + FC_WEIGHT_EXTRALIGHT) / 2) {
-    return 100;
+    return FontWeight(100);
   }
   if (aFcWeight <= (FC_WEIGHT_EXTRALIGHT + FC_WEIGHT_LIGHT) / 2) {
-    return 200;
+    return FontWeight(200);
   }
   if (aFcWeight <= (FC_WEIGHT_LIGHT + FC_WEIGHT_BOOK) / 2) {
-    return 300;
+    return FontWeight(300);
   }
   if (aFcWeight <= (FC_WEIGHT_REGULAR + FC_WEIGHT_MEDIUM) / 2) {
     // This includes FC_WEIGHT_BOOK
-    return 400;
+    return FontWeight(400);
   }
   if (aFcWeight <= (FC_WEIGHT_MEDIUM + FC_WEIGHT_DEMIBOLD) / 2) {
-    return 500;
+    return FontWeight(500);
   }
   if (aFcWeight <= (FC_WEIGHT_DEMIBOLD + FC_WEIGHT_BOLD) / 2) {
-    return 600;
+    return FontWeight(600);
   }
   if (aFcWeight <= (FC_WEIGHT_BOLD + FC_WEIGHT_EXTRABOLD) / 2) {
-    return 700;
+    return FontWeight(700);
   }
   if (aFcWeight <= (FC_WEIGHT_EXTRABOLD + FC_WEIGHT_BLACK) / 2) {
-    return 800;
+    return FontWeight(800);
   }
   if (aFcWeight <= FC_WEIGHT_BLACK) {
-    return 900;
+    return FontWeight(900);
   }
 
   // including FC_WEIGHT_EXTRABLACK
-  return 901;
+  return FontWeight(901);
 }
 
 static int16_t
@@ -311,7 +311,7 @@ CreateFaceForPattern(FcPattern* aPattern)
 }
 
 gfxFontconfigFontEntry::gfxFontconfigFontEntry(const nsAString& aFaceName,
-                                               uint16_t aWeight,
+                                               FontWeight aWeight,
                                                int16_t aStretch,
                                                uint8_t aStyle,
                                                const uint8_t *aData,
@@ -334,7 +334,7 @@ gfxFontconfigFontEntry::gfxFontconfigFontEntry(const nsAString& aFaceName,
 
 gfxFontconfigFontEntry::gfxFontconfigFontEntry(const nsAString& aFaceName,
                                                FcPattern* aFontPattern,
-                                               uint16_t aWeight,
+                                               FontWeight aWeight,
                                                int16_t aStretch,
                                                uint8_t aStyle)
         : gfxFontEntry(aFaceName), mFontPattern(aFontPattern),
@@ -1202,13 +1202,13 @@ gfxFontconfigFontFamily::FindStyleVariations(FontInfoData *aFontInfoData)
 
         if (LOG_FONTLIST_ENABLED()) {
             LOG_FONTLIST(("(fontlist) added (%s) to family (%s)"
-                 " with style: %s weight: %d stretch: %d"
+                 " with style: %s weight: %g stretch: %d"
                  " psname: %s fullname: %s",
                  NS_ConvertUTF16toUTF8(fontEntry->Name()).get(),
                  NS_ConvertUTF16toUTF8(Name()).get(),
                  (fontEntry->IsItalic()) ?
                   "italic" : (fontEntry->IsOblique() ? "oblique" : "normal"),
-                 fontEntry->Weight(), fontEntry->Stretch(),
+                 fontEntry->Weight().ToFloat(), fontEntry->Stretch(),
                  NS_ConvertUTF16toUTF8(psname).get(),
                  NS_ConvertUTF16toUTF8(fullname).get()));
         }
@@ -1857,7 +1857,7 @@ gfxFcPlatformFontList::GetDefaultFontForPlatform(const gfxFontStyle* aStyle)
 
 gfxFontEntry*
 gfxFcPlatformFontList::LookupLocalFont(const nsAString& aFontName,
-                                       uint16_t aWeight,
+                                       FontWeight aWeight,
                                        int16_t aStretch,
                                        uint8_t aStyle)
 {
@@ -1876,7 +1876,7 @@ gfxFcPlatformFontList::LookupLocalFont(const nsAString& aFontName,
 
 gfxFontEntry*
 gfxFcPlatformFontList::MakePlatformFont(const nsAString& aFontName,
-                                        uint16_t aWeight,
+                                        FontWeight aWeight,
                                         int16_t aStretch,
                                         uint8_t aStyle,
                                         const uint8_t* aFontData,
diff --git a/gfx/thebes/gfxFcPlatformFontList.h b/gfx/thebes/gfxFcPlatformFontList.h
index 55e735fac59e..fb0c49d2a8d2 100644
--- a/gfx/thebes/gfxFcPlatformFontList.h
+++ b/gfx/thebes/gfxFcPlatformFontList.h
@@ -10,6 +10,7 @@
 #include "gfxFontEntry.h"
 #include "gfxFT2FontBase.h"
 #include "gfxPlatformFontList.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/mozalloc.h"
 #include "nsAutoRef.h"
 #include "nsClassHashtable.h"
@@ -93,7 +94,7 @@ public:
     // used for data fonts where the fontentry takes ownership
     // of the font data and the FT_Face
     explicit gfxFontconfigFontEntry(const nsAString& aFaceName,
-                                    uint16_t aWeight,
+                                    FontWeight aWeight,
                                     int16_t aStretch,
                                     uint8_t aStyle,
                                     const uint8_t *aData,
@@ -103,7 +104,7 @@ public:
     // used for @font-face local system fonts with explicit patterns
     explicit gfxFontconfigFontEntry(const nsAString& aFaceName,
                                     FcPattern* aFontPattern,
-                                    uint16_t aWeight,
+                                    FontWeight aWeight,
                                     int16_t aStretch,
                                     uint8_t aStyle);
 
@@ -287,11 +288,13 @@ public:
         InfallibleTArray<mozilla::dom::SystemFontListEntry>* retValue);
 
     gfxFontEntry*
-    LookupLocalFont(const nsAString& aFontName, uint16_t aWeight,
+    LookupLocalFont(const nsAString& aFontName,
+                    FontWeight aWeight,
                     int16_t aStretch, uint8_t aStyle) override;
 
     gfxFontEntry*
-    MakePlatformFont(const nsAString& aFontName, uint16_t aWeight,
+    MakePlatformFont(const nsAString& aFontName,
+                     FontWeight aWeight,
                      int16_t aStretch,
                      uint8_t aStyle,
                      const uint8_t* aFontData,
diff --git a/gfx/thebes/gfxFont.cpp b/gfx/thebes/gfxFont.cpp
index a981e09f5a0c..b797bc00b5f7 100644
--- a/gfx/thebes/gfxFont.cpp
+++ b/gfx/thebes/gfxFont.cpp
@@ -7,6 +7,7 @@
 
 #include "mozilla/BinarySearch.h"
 #include "mozilla/DebugOnly.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/gfx/2D.h"
 #include "mozilla/MathAlgorithms.h"
 #include "mozilla/SVGContextPaint.h"
@@ -3521,7 +3522,7 @@ gfxFont::GetSmallCapsFont()
     style.size *= SMALL_CAPS_SCALE_FACTOR;
     style.variantCaps = NS_FONT_VARIANT_CAPS_NORMAL;
     gfxFontEntry* fe = GetFontEntry();
-    bool needsBold = style.weight >= 600 && !fe->IsBold();
+    bool needsBold = style.weight >= FontWeight(600) && !fe->IsBold();
     return fe->FindOrMakeFont(&style, needsBold, mUnicodeRangeMap);
 }
 
@@ -3531,7 +3532,7 @@ gfxFont::GetSubSuperscriptFont(int32_t aAppUnitsPerDevPixel)
     gfxFontStyle style(*GetStyle());
     style.AdjustForSubSuperscript(aAppUnitsPerDevPixel);
     gfxFontEntry* fe = GetFontEntry();
-    bool needsBold = style.weight >= 600 && !fe->IsBold();
+    bool needsBold = style.weight >= FontWeight(600) && !fe->IsBold();
     return fe->FindOrMakeFont(&style, needsBold, mUnicodeRangeMap);
 }
 
@@ -4110,7 +4111,8 @@ gfxFontStyle::gfxFontStyle() :
     size(DEFAULT_PIXEL_FONT_SIZE), sizeAdjust(-1.0f), baselineOffset(0.0f),
     languageOverride(NO_FONT_LANGUAGE_OVERRIDE),
     fontSmoothingBackgroundColor(NS_RGBA(0, 0, 0, 0)),
-    weight(NS_FONT_WEIGHT_NORMAL), stretch(NS_FONT_STRETCH_NORMAL),
+    weight(FontWeight::Normal()),
+    stretch(NS_FONT_STRETCH_NORMAL),
     style(NS_FONT_STYLE_NORMAL),
     variantCaps(NS_FONT_VARIANT_CAPS_NORMAL),
     variantSubSuper(NS_FONT_VARIANT_POSITION_NORMAL),
@@ -4121,7 +4123,9 @@ gfxFontStyle::gfxFontStyle() :
 {
 }
 
-gfxFontStyle::gfxFontStyle(uint8_t aStyle, uint16_t aWeight, int16_t aStretch,
+gfxFontStyle::gfxFontStyle(uint8_t aStyle,
+                           FontWeight aWeight,
+                           int16_t aStretch,
                            gfxFloat aSize,
                            nsAtom *aLanguage, bool aExplicitLanguage,
                            float aSizeAdjust, bool aSystemFont,
@@ -4133,7 +4137,8 @@ gfxFontStyle::gfxFontStyle(uint8_t aStyle, uint16_t aWeight, int16_t aStretch,
     size(aSize), sizeAdjust(aSizeAdjust), baselineOffset(0.0f),
     languageOverride(aLanguageOverride),
     fontSmoothingBackgroundColor(NS_RGBA(0, 0, 0, 0)),
-    weight(aWeight), stretch(aStretch),
+    weight(aWeight),
+    stretch(aStretch),
     style(aStyle),
     variantCaps(NS_FONT_VARIANT_CAPS_NORMAL),
     variantSubSuper(NS_FONT_VARIANT_POSITION_NORMAL),
@@ -4147,10 +4152,12 @@ gfxFontStyle::gfxFontStyle(uint8_t aStyle, uint16_t aWeight, int16_t aStretch,
     MOZ_ASSERT(!mozilla::IsNaN(size));
     MOZ_ASSERT(!mozilla::IsNaN(sizeAdjust));
 
-    if (weight > 900)
-        weight = 900;
-    if (weight < 100)
-        weight = 100;
+    if (weight > FontWeight(900)) {
+        weight = FontWeight(900);
+    }
+    if (weight < FontWeight(100)) {
+        weight = FontWeight(100);
+    }
 
     if (size >= FONT_MAX_SIZE) {
         size = FONT_MAX_SIZE;
diff --git a/gfx/thebes/gfxFont.h b/gfx/thebes/gfxFont.h
index 4889b8d890e5..b72563254c68 100644
--- a/gfx/thebes/gfxFont.h
+++ b/gfx/thebes/gfxFont.h
@@ -25,6 +25,7 @@
 #include "nsIObserver.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/Attributes.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/TypedEnumBits.h"
 #include "MainThreadUtils.h"
 #include <algorithm>
@@ -75,8 +76,10 @@ class SVGContextPaint;
 } // namespace mozilla
 
 struct gfxFontStyle {
+    typedef mozilla::FontWeight FontWeight;
+
     gfxFontStyle();
-    gfxFontStyle(uint8_t aStyle, uint16_t aWeight, int16_t aStretch,
+    gfxFontStyle(uint8_t aStyle, FontWeight aWeight, int16_t aStretch,
                  gfxFloat aSize, nsAtom *aLanguage, bool aExplicitLanguage,
                  float aSizeAdjust, bool aSystemFont,
                  bool aPrinterFont,
@@ -137,7 +140,7 @@ struct gfxFontStyle {
     nscolor fontSmoothingBackgroundColor;
 
     // The weight of the font: 100, 200, ... 900.
-    uint16_t weight;
+    FontWeight weight;
 
     // The stretch of the font (the sum of various NS_FONT_STRETCH_*
     // constants; see gfxFontConstants.h).
@@ -184,8 +187,8 @@ struct gfxFontStyle {
     }
 
     PLDHashNumber Hash() const {
-        return ((style + (systemFont << 7) +
-            (weight << 8)) + uint32_t(size*1000) + int32_t(sizeAdjust*1000)) ^
+        return (style + (systemFont << 7) + (weight.ForHash() << 8) +
+            uint32_t(size*1000) + int32_t(sizeAdjust*1000)) ^
             nsRefPtrHashKey<nsAtom>::HashKey(language);
     }
 
diff --git a/gfx/thebes/gfxFontEntry.cpp b/gfx/thebes/gfxFontEntry.cpp
index cc7c76f73e35..7931d64e9e3c 100644
--- a/gfx/thebes/gfxFontEntry.cpp
+++ b/gfx/thebes/gfxFontEntry.cpp
@@ -3,12 +3,14 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#include "gfxFontEntry.h"
+
 #include "mozilla/DebugOnly.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/MathAlgorithms.h"
 
 #include "mozilla/Logging.h"
 
-#include "gfxFontEntry.h"
 #include "gfxTextRun.h"
 #include "gfxPlatform.h"
 #include "nsGkAtoms.h"
@@ -1234,24 +1236,25 @@ StretchDistance(int16_t aFontStretch, int16_t aTargetStretch)
 
 // weight distance ==> [0,1598]
 static inline uint32_t
-WeightDistance(uint32_t aFontWeight, uint32_t aTargetWeight)
+WeightDistance(FontWeight aFontWeight, FontWeight aTargetWeight)
 {
     // Compute a measure of the "distance" between the requested
     // weight and the given fontEntry
 
-    int32_t distance = 0, addedDistance = 0;
+    float distance = 0.0f, addedDistance = 0.0f;
     if (aTargetWeight != aFontWeight) {
-        if (aTargetWeight > 500) {
+        if (aTargetWeight > FontWeight(500)) {
             distance = aFontWeight - aTargetWeight;
-        } else if (aTargetWeight < 400) {
+        } else if (aTargetWeight < FontWeight(400)) {
             distance = aTargetWeight - aFontWeight;
         } else {
             // special case - target is between 400 and 500
 
             // font weights between 400 and 500 are close
-            if (aFontWeight >= 400 && aFontWeight <= 500) {
+            if (aFontWeight >= FontWeight(400) &&
+                aFontWeight <= FontWeight(500)) {
                 if (aFontWeight < aTargetWeight) {
-                    distance = 500 - aFontWeight;
+                    distance = FontWeight(500) - aFontWeight;
                 } else {
                     distance = aFontWeight - aTargetWeight;
                 }
@@ -1263,7 +1266,7 @@ WeightDistance(uint32_t aFontWeight, uint32_t aTargetWeight)
                 addedDistance = 100;
             }
         }
-        if (distance < 0) {
+        if (distance < 0.0f) {
             distance = -distance + REVERSE_WEIGHT_DISTANCE;
         }
         distance += addedDistance;
@@ -1307,7 +1310,7 @@ gfxFontFamily::FindAllFontsForStyle(const gfxFontStyle& aFontStyle,
 
     aNeedsSyntheticBold = false;
 
-    bool wantBold = aFontStyle.weight >= 600;
+    bool wantBold = aFontStyle.weight >= FontWeight(600);
     gfxFontEntry *fe = nullptr;
 
     // If the family has only one face, we simply return it; no further
@@ -1406,7 +1409,7 @@ gfxFontFamily::FindAllFontsForStyle(const gfxFontStyle& aFontStyle,
 
     if (matched) {
         aFontEntryList.AppendElement(matched);
-        if (!matched->IsBold() && aFontStyle.weight >= 600 &&
+        if (!matched->IsBold() && aFontStyle.weight >= FontWeight(600) &&
             aFontStyle.allowSyntheticWeight) {
             aNeedsSyntheticBold = true;
         }
@@ -1442,7 +1445,7 @@ gfxFontFamily::CheckForSimpleFamily()
             return;
         }
         uint8_t faceIndex = (fe->IsItalic() ? kItalicMask : 0) |
-                            (fe->Weight() >= 600 ? kBoldMask : 0);
+                            (fe->Weight() >= FontWeight(600) ? kBoldMask : 0);
         if (faces[faceIndex]) {
             return; // two faces resolve to the same slot; family isn't "simple"
         }
@@ -1501,7 +1504,7 @@ CalcStyleMatch(gfxFontEntry *aFontEntry, const gfxFontStyle *aStyle)
          }
 
         // measure of closeness of weight to the desired value
-        rank += 9 - Abs((aFontEntry->Weight() - aStyle->weight) / 100);
+        rank += 9 - Abs((aFontEntry->Weight() - aStyle->weight) / 100.0f);
     } else {
         // if no font to match, prefer non-bold, non-italic fonts
         if (aFontEntry->IsUpright()) {
diff --git a/gfx/thebes/gfxFontEntry.h b/gfx/thebes/gfxFontEntry.h
index 728480e3a152..23da86f0ff50 100644
--- a/gfx/thebes/gfxFontEntry.h
+++ b/gfx/thebes/gfxFontEntry.h
@@ -20,6 +20,7 @@
 #include "nsUnicodeScriptCodes.h"
 #include "nsDataHashtable.h"
 #include "harfbuzz/hb.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/gfx/2D.h"
 #include "mozilla/UniquePtr.h"
 #include "mozilla/WeakPtr.h"
@@ -109,6 +110,7 @@ struct gfxFontFeatureInfo {
 
 class gfxFontEntry {
 public:
+    typedef mozilla::FontWeight FontWeight;
     typedef mozilla::gfx::DrawTarget DrawTarget;
     typedef mozilla::unicode::Script Script;
 
@@ -139,7 +141,7 @@ public:
     // returns Name() if nothing better is available.
     virtual nsString RealFaceName();
 
-    uint16_t Weight() const { return mWeight; }
+    FontWeight Weight() const { return mWeight; }
     int16_t Stretch() const { return mStretch; }
 
     bool IsUserFont() const { return mIsDataUserFont || mIsLocalUserFont; }
@@ -148,7 +150,7 @@ public:
     bool IsItalic() const { return mStyle == NS_FONT_STYLE_ITALIC; }
     bool IsOblique() const { return mStyle == NS_FONT_STYLE_OBLIQUE; }
     bool IsUpright() const { return mStyle == NS_FONT_STYLE_NORMAL; }
-    bool IsBold() const { return mWeight >= 600; } // bold == weights 600 and above
+    bool IsBold() const { return mWeight >= FontWeight(600); } // bold == weights 600 and above
     bool IgnoreGDEF() const { return mIgnoreGDEF; }
     bool IgnoreGSUB() const { return mIgnoreGSUB; }
 
@@ -161,7 +163,7 @@ public:
     bool IsNormalStyle() const
     {
         return IsUpright() &&
-               Weight() == NS_FONT_WEIGHT_NORMAL &&
+               Weight() == FontWeight::Normal() &&
                Stretch() == NS_FONT_STRETCH_NORMAL;
     }
 
@@ -402,7 +404,7 @@ public:
     uint32_t         mDefaultSubSpaceFeatures[(int(Script::NUM_SCRIPT_CODES) + 31) / 32];
     uint32_t         mNonDefaultSubSpaceFeatures[(int(Script::NUM_SCRIPT_CODES) + 31) / 32];
 
-    uint16_t         mWeight;
+    FontWeight       mWeight;
     int16_t          mStretch;
 
     RefPtr<gfxCharacterMap> mCharacterMap;
diff --git a/gfx/thebes/gfxGDIFont.cpp b/gfx/thebes/gfxGDIFont.cpp
index 7b0c9c506f9f..520d194e094c 100644
--- a/gfx/thebes/gfxGDIFont.cpp
+++ b/gfx/thebes/gfxGDIFont.cpp
@@ -445,20 +445,20 @@ gfxGDIFont::FillLogFont(LOGFONTW& aLogFont, gfxFloat aSize)
 {
     GDIFontEntry *fe = static_cast<GDIFontEntry*>(GetFontEntry());
 
-    uint16_t weight;
+    FontWeight weight;
     if (fe->IsUserFont()) {
         if (fe->IsLocalUserFont()) {
             // for local user fonts, don't change the original weight
             // in the entry's logfont, because that could alter the
             // choice of actual face used (bug 724231)
-            weight = 0;
+            weight = FontWeight(0);
         } else {
             // avoid GDI synthetic bold which occurs when weight
             // specified is >= font data weight + 200
-            weight = mNeedsBold ? 700 : 200;
+            weight = mNeedsBold ? FontWeight(700) : FontWeight(200);
         }
     } else {
-        weight = mNeedsBold ? 700 : fe->Weight();
+        weight = mNeedsBold ? FontWeight(700) : fe->Weight();
     }
 
     fe->FillLogFont(&aLogFont, weight, aSize);
diff --git a/gfx/thebes/gfxGDIFontList.cpp b/gfx/thebes/gfxGDIFontList.cpp
index a378ef6933fd..22a363e1f981 100644
--- a/gfx/thebes/gfxGDIFontList.cpp
+++ b/gfx/thebes/gfxGDIFontList.cpp
@@ -115,7 +115,8 @@ FontTypeToOutPrecision(uint8_t fontType)
 
 GDIFontEntry::GDIFontEntry(const nsAString& aFaceName,
                            gfxWindowsFontType aFontType,
-                           uint8_t aStyle, uint16_t aWeight,
+                           uint8_t aStyle,
+                           FontWeight aWeight,
                            int16_t aStretch,
                            gfxUserFontData *aUserFontData)
     : gfxFontEntry(aFaceName),
@@ -255,7 +256,8 @@ GDIFontEntry::LookupUnscaledFont(HFONT aFont)
 
 void
 GDIFontEntry::FillLogFont(LOGFONTW *aLogFont,
-                          uint16_t aWeight, gfxFloat aSize)
+                          FontWeight aWeight,
+                          gfxFloat aSize)
 {
     memcpy(aLogFont, &mLogFont, sizeof(LOGFONTW));
 
@@ -270,8 +272,8 @@ GDIFontEntry::FillLogFont(LOGFONTW *aLogFont,
     // for installed families with no bold face, and for downloaded fonts
     // (but NOT for local user fonts, because it could cause a different,
     // glyph-incompatible face to be used)
-    if (aWeight) {
-        aLogFont->lfWeight = aWeight;
+    if (aWeight.ToFloat() != 0.0f) {
+        aLogFont->lfWeight = LONG(aWeight.ToFloat());
     }
 
     // for non-local() user fonts, we never want to apply italics here;
@@ -303,7 +305,7 @@ GDIFontEntry::TestCharacterMap(uint32_t aCh)
         if (!IsUpright()) {
             fakeStyle.style = NS_FONT_STYLE_ITALIC;
         }
-        fakeStyle.weight = mWeight * 100;
+        fakeStyle.weight = mWeight;
 
         RefPtr<gfxFont> tempFont = FindOrMakeFont(&fakeStyle, false);
         if (!tempFont || !tempFont->Valid())
@@ -382,7 +384,7 @@ GDIFontEntry::InitLogFont(const nsAString& aName,
     // it may give us a regular one based on weight.  Windows should
     // do fake italic for us in that case.
     mLogFont.lfItalic         = !IsUpright();
-    mLogFont.lfWeight         = mWeight;
+    mLogFont.lfWeight         = int(mWeight.ToFloat());
 
     int len = std::min<int>(aName.Length(), LF_FACESIZE - 1);
     memcpy(&mLogFont.lfFaceName, aName.BeginReading(), len * sizeof(char16_t));
@@ -393,7 +395,8 @@ GDIFontEntry*
 GDIFontEntry::CreateFontEntry(const nsAString& aName,
                               gfxWindowsFontType aFontType,
                               uint8_t aStyle,
-                              uint16_t aWeight, int16_t aStretch,
+                              FontWeight aWeight,
+                              int16_t aStretch,
                               gfxUserFontData* aUserFontData)
 {
     // jtdfix - need to set charset, unicode ranges, pitch/family
@@ -464,7 +467,7 @@ GDIFontFamily::FamilyAddStylesProc(const ENUMLOGFONTEXW *lpelfe,
     for (uint32_t i = 0; i < ff->mAvailableFonts.Length(); ++i) {
         fe = static_cast<GDIFontEntry*>(ff->mAvailableFonts[i].get());
         // check if we already know about this face
-        if (fe->mWeight == logFont.lfWeight &&
+        if (fe->mWeight == FontWeight(int32_t(logFont.lfWeight)) &&
             fe->IsItalic() == (logFont.lfItalic == 0xFF)) {
             // update the charset bit here since this could be different
             // XXX Can we still do this now that we store mCharset
@@ -481,7 +484,7 @@ GDIFontFamily::FamilyAddStylesProc(const ENUMLOGFONTEXW *lpelfe,
                            NS_FONT_STYLE_ITALIC : NS_FONT_STYLE_NORMAL);
     fe = GDIFontEntry::CreateFontEntry(nsDependentString(lpelfe->elfFullName),
                                        feType, italicStyle,
-                                       (uint16_t) (logFont.lfWeight), 0,
+                                       FontWeight(int32_t(logFont.lfWeight)), 0,
                                        nullptr);
     if (!fe)
         return 1;
@@ -707,7 +710,7 @@ gfxGDIFontList::EnumFontFamExProc(ENUMLOGFONTEXW *lpelfe,
 
 gfxFontEntry* 
 gfxGDIFontList::LookupLocalFont(const nsAString& aFontName,
-                                uint16_t aWeight,
+                                FontWeight aWeight,
                                 int16_t aStretch,
                                 uint8_t aStyle)
 {
@@ -734,7 +737,7 @@ gfxGDIFontList::LookupLocalFont(const nsAString& aFontName,
     fe->mIsLocalUserFont = true;
 
     // make the new font entry match the userfont entry style characteristics
-    fe->mWeight = (aWeight == 0 ? 400 : aWeight);
+    fe->mWeight = (aWeight == FontWeight(0) ? FontWeight(400) : aWeight);
     fe->mStyle = aStyle;
 
     return fe;
@@ -799,7 +802,7 @@ FixupSymbolEncodedFont(uint8_t* aFontData, uint32_t aLength)
 
 gfxFontEntry*
 gfxGDIFontList::MakePlatformFont(const nsAString& aFontName,
-                                 uint16_t aWeight,
+                                 FontWeight aWeight,
                                  int16_t aStretch,
                                  uint8_t aStyle,
                                  const uint8_t* aFontData,
@@ -864,7 +867,7 @@ gfxGDIFontList::MakePlatformFont(const nsAString& aFontName,
 
     // make a new font entry using the unique name
     WinUserFontData *winUserFontData = new WinUserFontData(fontRef);
-    uint16_t w = (aWeight == 0 ? 400 : aWeight);
+    FontWeight w = (aWeight == FontWeight(0) ? FontWeight(400) : aWeight);
 
     GDIFontEntry *fe = GDIFontEntry::CreateFontEntry(uniqueName,
         gfxWindowsFontType(isCFF ? GFX_FONT_TYPE_PS_OPENTYPE : GFX_FONT_TYPE_TRUETYPE) /*type*/,
diff --git a/gfx/thebes/gfxGDIFontList.h b/gfx/thebes/gfxGDIFontList.h
index c197d473dfb2..53b97308359a 100644
--- a/gfx/thebes/gfxGDIFontList.h
+++ b/gfx/thebes/gfxGDIFontList.h
@@ -6,6 +6,7 @@
 #ifndef GFX_GDIFONTLIST_H
 #define GFX_GDIFONTLIST_H
 
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/MemoryReporting.h"
 #include "gfxWindowsPlatform.h"
 #include "gfxPlatformFontList.h"
@@ -107,11 +108,15 @@ enum gfxWindowsFontType {
 class GDIFontEntry : public gfxFontEntry
 {
 public:
+    typedef mozilla::FontWeight FontWeight;
+
     LPLOGFONTW GetLogFont() { return &mLogFont; }
 
     nsresult ReadCMAP(FontInfoData *aFontInfoData = nullptr) override;
 
-    void FillLogFont(LOGFONTW *aLogFont, uint16_t aWeight, gfxFloat aSize);
+    void FillLogFont(LOGFONTW *aLogFont,
+                     FontWeight aWeight,
+                     gfxFloat aSize);
 
     static gfxWindowsFontType DetermineFontType(const NEWTEXTMETRICW& metrics, 
                                                 DWORD fontType)
@@ -164,12 +169,13 @@ public:
     static GDIFontEntry* CreateFontEntry(const nsAString& aName,
                                          gfxWindowsFontType aFontType,
                                          uint8_t aStyle,
-                                         uint16_t aWeight, int16_t aStretch,
+                                         FontWeight aWeight,
+                                         int16_t aStretch,
                                          gfxUserFontData* aUserFontData);
 
     // create a font entry for a font referenced by its fullname
     static GDIFontEntry* LoadLocalFont(const nsAString& aFontName,
-                                       uint16_t aWeight,
+                                       FontWeight aWeight,
                                        int16_t aStretch,
                                        uint8_t aStyle);
 
@@ -182,7 +188,7 @@ protected:
     friend class gfxGDIFont;
 
     GDIFontEntry(const nsAString& aFaceName, gfxWindowsFontType aFontType,
-                 uint8_t aStyle, uint16_t aWeight, int16_t aStretch,
+                 uint8_t aStyle, FontWeight aWeight, int16_t aStretch,
                  gfxUserFontData *aUserFontData);
 
     void InitLogFont(const nsAString& aName, gfxWindowsFontType aFontType);
@@ -314,6 +320,8 @@ private:
 
 class gfxGDIFontList : public gfxPlatformFontList {
 public:
+    typedef mozilla::FontWeight FontWeight;
+
     static gfxGDIFontList* PlatformFontList() {
         return static_cast<gfxGDIFontList*>(sPlatformFontList);
     }
@@ -330,12 +338,12 @@ public:
                             gfxFloat aDevToCssSize = 1.0) override;
 
     virtual gfxFontEntry* LookupLocalFont(const nsAString& aFontName,
-                                          uint16_t aWeight,
+                                          FontWeight aWeight,
                                           int16_t aStretch,
                                           uint8_t aStyle);
 
     virtual gfxFontEntry* MakePlatformFont(const nsAString& aFontName,
-                                           uint16_t aWeight,
+                                           FontWeight aWeight,
                                            int16_t aStretch,
                                            uint8_t aStyle,
                                            const uint8_t* aFontData,
diff --git a/gfx/thebes/gfxMacPlatformFontList.h b/gfx/thebes/gfxMacPlatformFontList.h
index f821cf6b4c8a..838821fd2e2a 100644
--- a/gfx/thebes/gfxMacPlatformFontList.h
+++ b/gfx/thebes/gfxMacPlatformFontList.h
@@ -8,6 +8,7 @@
 
 #include <CoreFoundation/CoreFoundation.h>
 
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/MemoryReporting.h"
 #include "nsDataHashtable.h"
 #include "nsRefPtrHashtable.h"
@@ -30,13 +31,13 @@ class MacOSFontEntry : public gfxFontEntry
 public:
     friend class gfxMacPlatformFontList;
 
-    MacOSFontEntry(const nsAString& aPostscriptName, int32_t aWeight,
+    MacOSFontEntry(const nsAString& aPostscriptName, FontWeight aWeight,
                    bool aIsStandardFace = false,
                    double aSizeHint = 0.0);
 
     // for use with data fonts
     MacOSFontEntry(const nsAString& aPostscriptName, CGFontRef aFontRef,
-                   uint16_t aWeight, uint16_t aStretch, uint8_t aStyle,
+                   FontWeight aWeight, uint16_t aStretch, uint8_t aStyle,
                    bool aIsDataUserFont, bool aIsLocal);
 
     virtual ~MacOSFontEntry() {
@@ -130,12 +131,12 @@ public:
     bool GetStandardFamilyName(const nsAString& aFontName, nsAString& aFamilyName) override;
 
     gfxFontEntry* LookupLocalFont(const nsAString& aFontName,
-                                  uint16_t aWeight,
+                                  FontWeight aWeight,
                                   int16_t aStretch,
                                   uint8_t aStyle) override;
 
     gfxFontEntry* MakePlatformFont(const nsAString& aFontName,
-                                   uint16_t aWeight,
+                                   FontWeight aWeight,
                                    int16_t aStretch,
                                    uint8_t aStyle,
                                    const uint8_t* aFontData,
diff --git a/gfx/thebes/gfxMacPlatformFontList.mm b/gfx/thebes/gfxMacPlatformFontList.mm
index b9e8a17b8a47..0231bf5d3aae 100644
--- a/gfx/thebes/gfxMacPlatformFontList.mm
+++ b/gfx/thebes/gfxMacPlatformFontList.mm
@@ -65,6 +65,7 @@
 
 #include "mozilla/dom/ContentChild.h"
 #include "mozilla/dom/ContentParent.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/Sprintf.h"
@@ -363,7 +364,7 @@ MacOSFontEntry::IsCFF()
 }
 
 MacOSFontEntry::MacOSFontEntry(const nsAString& aPostscriptName,
-                               int32_t aWeight,
+                               FontWeight aWeight,
                                bool aIsStandardFace,
                                double aSizeHint)
     : gfxFontEntry(aPostscriptName, aIsStandardFace),
@@ -387,7 +388,8 @@ MacOSFontEntry::MacOSFontEntry(const nsAString& aPostscriptName,
 
 MacOSFontEntry::MacOSFontEntry(const nsAString& aPostscriptName,
                                CGFontRef aFontRef,
-                               uint16_t aWeight, uint16_t aStretch,
+                               FontWeight aWeight,
+                               uint16_t aStretch,
                                uint8_t aStyle,
                                bool aIsDataUserFont,
                                bool aIsLocalUserFont)
@@ -902,7 +904,8 @@ gfxMacFontFamily::FindStyleVariations(FontInfoData *aFontInfoData)
 
         // create a font entry
         MacOSFontEntry *fontEntry =
-            new MacOSFontEntry(postscriptFontName, cssWeight, isStandardFace, mSizeHint);
+            new MacOSFontEntry(postscriptFontName, FontWeight(cssWeight),
+                               isStandardFace, mSizeHint);
         if (!fontEntry) {
             break;
         }
@@ -1530,7 +1533,7 @@ gfxMacPlatformFontList::AppleWeightToCSSWeight(int32_t aAppleWeight)
 
 gfxFontEntry*
 gfxMacPlatformFontList::LookupLocalFont(const nsAString& aFontName,
-                                        uint16_t aWeight,
+                                        FontWeight aWeight,
                                         int16_t aStretch,
                                         uint8_t aStyle)
 {
@@ -1545,8 +1548,8 @@ gfxMacPlatformFontList::LookupLocalFont(const nsAString& aFontName,
         return nullptr;
     }
 
-    NS_ASSERTION(aWeight >= 100 && aWeight <= 900,
-                 "bogus font weight value!");
+    MOZ_ASSERT(aWeight >= FontWeight(100) && aWeight <= FontWeight(900),
+               "bogus font weight value!");
 
     newFontEntry =
         new MacOSFontEntry(aFontName, fontRef, aWeight, aStretch, aStyle,
@@ -1563,7 +1566,7 @@ static void ReleaseData(void *info, const void *data, size_t size)
 
 gfxFontEntry*
 gfxMacPlatformFontList::MakePlatformFont(const nsAString& aFontName,
-                                         uint16_t aWeight,
+                                         FontWeight aWeight,
                                          int16_t aStretch,
                                          uint8_t aStyle,
                                          const uint8_t* aFontData,
@@ -1571,7 +1574,8 @@ gfxMacPlatformFontList::MakePlatformFont(const nsAString& aFontName,
 {
     NS_ASSERTION(aFontData, "MakePlatformFont called with null data");
 
-    NS_ASSERTION(aWeight >= 100 && aWeight <= 900, "bogus font weight value!");
+    MOZ_ASSERT(aWeight >= FontWeight(100) && aWeight <= FontWeight(900),
+               "bogus font weight value!");
 
     // create the font entry
     nsAutoString uniqueName;
@@ -1701,7 +1705,7 @@ gfxMacPlatformFontList::LookupSystemFont(LookAndFeel::FontID aSystemFontID,
     aFontStyle.style =
         (traits & NSFontItalicTrait) ?  NS_FONT_STYLE_ITALIC : NS_FONT_STYLE_NORMAL;
     aFontStyle.weight =
-        (traits & NSFontBoldTrait) ? NS_FONT_WEIGHT_BOLD : NS_FONT_WEIGHT_NORMAL;
+        (traits & NSFontBoldTrait) ? FontWeight::Bold() : FontWeight::Normal();
     aFontStyle.stretch =
         (traits & NSFontExpandedTrait) ?
             NS_FONT_STRETCH_EXPANDED : (traits & NSFontCondensedTrait) ?
diff --git a/gfx/thebes/gfxPlatform.cpp b/gfx/thebes/gfxPlatform.cpp
index 174c7d773bab..abe2bb655768 100644
--- a/gfx/thebes/gfxPlatform.cpp
+++ b/gfx/thebes/gfxPlatform.cpp
@@ -3,6 +3,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/layers/CompositorManagerChild.h"
 #include "mozilla/layers/CompositorThread.h"
 #include "mozilla/layers/ImageBridgeChild.h"
@@ -1757,7 +1758,7 @@ gfxPlatform::IsFontFormatSupported(uint32_t aFormatFlags)
 
 gfxFontEntry*
 gfxPlatform::LookupLocalFont(const nsAString& aFontName,
-                             uint16_t aWeight,
+                             FontWeight aWeight,
                              int16_t aStretch,
                              uint8_t aStyle)
 {
@@ -1769,7 +1770,7 @@ gfxPlatform::LookupLocalFont(const nsAString& aFontName,
 
 gfxFontEntry*
 gfxPlatform::MakePlatformFont(const nsAString& aFontName,
-                              uint16_t aWeight,
+                              FontWeight aWeight,
                               int16_t aStretch,
                               uint8_t aStyle,
                               const uint8_t* aFontData,
diff --git a/gfx/thebes/gfxPlatform.h b/gfx/thebes/gfxPlatform.h
index a13b3b42891e..b3cb4f32fe65 100644
--- a/gfx/thebes/gfxPlatform.h
+++ b/gfx/thebes/gfxPlatform.h
@@ -6,6 +6,7 @@
 #ifndef GFX_PLATFORM_H
 #define GFX_PLATFORM_H
 
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/Logging.h"
 #include "mozilla/gfx/Types.h"
 #include "nsTArray.h"
@@ -158,6 +159,7 @@ class gfxPlatform {
     friend class SRGBOverrideObserver;
 
 public:
+    typedef mozilla::FontWeight FontWeight;
     typedef mozilla::gfx::Color Color;
     typedef mozilla::gfx::DataSourceSurface DataSourceSurface;
     typedef mozilla::gfx::DrawTarget DrawTarget;
@@ -391,7 +393,7 @@ public:
      * who must either AddRef() or delete.
      */
     virtual gfxFontEntry* LookupLocalFont(const nsAString& aFontName,
-                                          uint16_t aWeight,
+                                          FontWeight aWeight,
                                           int16_t aStretch,
                                           uint8_t aStyle);
 
@@ -404,7 +406,7 @@ public:
      * who must either AddRef() or delete.
      */
     virtual gfxFontEntry* MakePlatformFont(const nsAString& aFontName,
-                                           uint16_t aWeight,
+                                           FontWeight aWeight,
                                            int16_t aStretch,
                                            uint8_t aStyle,
                                            const uint8_t* aFontData,
diff --git a/gfx/thebes/gfxPlatformFontList.h b/gfx/thebes/gfxPlatformFontList.h
index 8d099f1bd8c1..d7d3bdf63788 100644
--- a/gfx/thebes/gfxPlatformFontList.h
+++ b/gfx/thebes/gfxPlatformFontList.h
@@ -19,6 +19,7 @@
 
 #include "nsIMemoryReporter.h"
 #include "mozilla/Attributes.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/Mutex.h"
 #include "mozilla/RangedArray.h"
@@ -97,6 +98,7 @@ class gfxPlatformFontList : public gfxFontInfoLoader
     friend class InitOtherFamilyNamesRunnable;
 
 public:
+    typedef mozilla::FontWeight FontWeight;
     typedef mozilla::unicode::Script Script;
 
     static gfxPlatformFontList* PlatformFontList() {
@@ -186,14 +188,14 @@ public:
 
     // look up a font by name on the host platform
     virtual gfxFontEntry* LookupLocalFont(const nsAString& aFontName,
-                                          uint16_t aWeight,
+                                          FontWeight aWeight,
                                           int16_t aStretch,
                                           uint8_t aStyle) = 0;
 
     // create a new platform font from downloaded data (@font-face)
     // this method is responsible to ensure aFontData is free()'d
     virtual gfxFontEntry* MakePlatformFont(const nsAString& aFontName,
-                                           uint16_t aWeight,
+                                           FontWeight aWeight,
                                            int16_t aStretch,
                                            uint8_t aStyle,
                                            const uint8_t* aFontData,
diff --git a/gfx/thebes/gfxPlatformGtk.cpp b/gfx/thebes/gfxPlatformGtk.cpp
index 45274277e90c..a6f2569651db 100644
--- a/gfx/thebes/gfxPlatformGtk.cpp
+++ b/gfx/thebes/gfxPlatformGtk.cpp
@@ -26,6 +26,7 @@
 #include "base/task.h"
 #include "base/thread.h"
 #include "base/message_loop.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/gfx/Logging.h"
 
 #include "mozilla/gfx/2D.h"
@@ -274,7 +275,7 @@ gfxPlatformGtk::CreateFontGroup(const FontFamilyList& aFontFamilyList,
 
 gfxFontEntry*
 gfxPlatformGtk::LookupLocalFont(const nsAString& aFontName,
-                                uint16_t aWeight,
+                                FontWeight aWeight,
                                 int16_t aStretch,
                                 uint8_t aStyle)
 {
@@ -285,7 +286,7 @@ gfxPlatformGtk::LookupLocalFont(const nsAString& aFontName,
 
 gfxFontEntry*
 gfxPlatformGtk::MakePlatformFont(const nsAString& aFontName,
-                                 uint16_t aWeight,
+                                 FontWeight aWeight,
                                  int16_t aStretch,
                                  uint8_t aStyle,
                                  const uint8_t* aFontData,
diff --git a/gfx/thebes/gfxPlatformGtk.h b/gfx/thebes/gfxPlatformGtk.h
index 390e7b22f645..2055574365cd 100644
--- a/gfx/thebes/gfxPlatformGtk.h
+++ b/gfx/thebes/gfxPlatformGtk.h
@@ -66,7 +66,7 @@ public:
      * support @font-face src local() )
      */
     virtual gfxFontEntry* LookupLocalFont(const nsAString& aFontName,
-                                          uint16_t aWeight,
+                                          FontWeight aWeight,
                                           int16_t aStretch,
                                           uint8_t aStyle) override;
 
@@ -75,7 +75,7 @@ public:
      *
      */
     virtual gfxFontEntry* MakePlatformFont(const nsAString& aFontName,
-                                           uint16_t aWeight,
+                                           FontWeight aWeight,
                                            int16_t aStretch,
                                            uint8_t aStyle,
                                            const uint8_t* aFontData,
diff --git a/gfx/thebes/gfxTextRun.cpp b/gfx/thebes/gfxTextRun.cpp
index ad41d704d375..a33b5600c56f 100644
--- a/gfx/thebes/gfxTextRun.cpp
+++ b/gfx/thebes/gfxTextRun.cpp
@@ -1768,9 +1768,9 @@ gfxTextRun::Dump(FILE* aOutput) {
         NS_ConvertUTF16toUTF8 fontName(font->GetName());
         nsAutoCString lang;
         style->language->ToUTF8String(lang);
-        fprintf(aOutput, "%d: %s %f/%d/%d/%s", glyphRuns[i].mCharacterOffset,
+        fprintf(aOutput, "%d: %s %f/%g/%d/%s", glyphRuns[i].mCharacterOffset,
                 fontName.get(), style->size,
-                style->weight, style->style, lang.get());
+                style->weight.ToFloat(), style->style, lang.get());
     }
     fputc(']', aOutput);
 }
@@ -2416,7 +2416,7 @@ gfxFontGroup::InitTextRun(DrawTarget* aDrawTarget,
                 nsAutoCString str((const char*)aString, aLength);
                 MOZ_LOG(log, LogLevel::Warning,\
                        ("(%s) fontgroup: [%s] default: %s lang: %s script: %d "
-                        "len %d weight: %d width: %d style: %s size: %6.2f %zu-byte "
+                        "len %d weight: %g width: %d style: %s size: %6.2f %zu-byte "
                         "TEXTRUN [%s] ENDTEXTRUN\n",
                         (mStyle.systemFont ? "textrunui" : "textrun"),
                         NS_ConvertUTF16toUTF8(families).get(),
@@ -2425,7 +2425,7 @@ gfxFontGroup::InitTextRun(DrawTarget* aDrawTarget,
                          (mFamilyList.GetDefaultFontType() == eFamily_sans_serif ?
                           "sans-serif" : "none")),
                         lang.get(), static_cast<int>(Script::LATIN), aLength,
-                        uint32_t(mStyle.weight), uint32_t(mStyle.stretch),
+                        mStyle.weight.ToFloat(), uint32_t(mStyle.stretch),
                         (mStyle.style & NS_FONT_STYLE_ITALIC ? "italic" :
                         (mStyle.style & NS_FONT_STYLE_OBLIQUE ? "oblique" :
                                                                 "normal")),
@@ -2464,7 +2464,7 @@ gfxFontGroup::InitTextRun(DrawTarget* aDrawTarget,
                     uint32_t runLen = runLimit - runStart;
                     MOZ_LOG(log, LogLevel::Warning,\
                            ("(%s) fontgroup: [%s] default: %s lang: %s script: %d "
-                            "len %d weight: %d width: %d style: %s size: %6.2f "
+                            "len %d weight: %g width: %d style: %s size: %6.2f "
                             "%zu-byte TEXTRUN [%s] ENDTEXTRUN\n",
                             (mStyle.systemFont ? "textrunui" : "textrun"),
                             NS_ConvertUTF16toUTF8(families).get(),
@@ -2473,7 +2473,7 @@ gfxFontGroup::InitTextRun(DrawTarget* aDrawTarget,
                              (mFamilyList.GetDefaultFontType() == eFamily_sans_serif ?
                               "sans-serif" : "none")),
                             lang.get(), static_cast<int>(runScript), runLen,
-                            uint32_t(mStyle.weight), uint32_t(mStyle.stretch),
+                            mStyle.weight.ToFloat(), uint32_t(mStyle.stretch),
                             (mStyle.style & NS_FONT_STYLE_ITALIC ? "italic" :
                             (mStyle.style & NS_FONT_STYLE_OBLIQUE ? "oblique" :
                                                                     "normal")),
@@ -2818,7 +2818,7 @@ gfxFontGroup::FindFallbackFaceForChar(gfxFontFamily* aFamily, uint32_t aCh)
         return nullptr;
     }
 
-    bool needsBold = mStyle.weight >= 600 && !fe->IsBold() &&
+    bool needsBold = mStyle.weight >= FontWeight(600) && !fe->IsBold() &&
                      mStyle.allowSyntheticWeight;
     return fe->FindOrMakeFont(&mStyle, needsBold);
 }
@@ -3444,7 +3444,7 @@ gfxFontGroup::WhichSystemFontSupportsChar(uint32_t aCh, uint32_t aNextCh,
         gfxPlatformFontList::PlatformFontList()->
             SystemFindFontForChar(aCh, aNextCh, aRunScript, &mStyle);
     if (fe) {
-        bool wantBold = mStyle.weight >= 600;
+        bool wantBold = mStyle.weight >= FontWeight(600);
         return fe->FindOrMakeFont(&mStyle, wantBold && !fe->IsBold());
     }
 
diff --git a/gfx/thebes/gfxUserFontSet.cpp b/gfx/thebes/gfxUserFontSet.cpp
index 298ce0d9c63f..c31e44cb5253 100644
--- a/gfx/thebes/gfxUserFontSet.cpp
+++ b/gfx/thebes/gfxUserFontSet.cpp
@@ -10,6 +10,7 @@
 #include "gfxPrefs.h"
 #include "nsIProtocolHandler.h"
 #include "gfxFontConstants.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/Services.h"
 #include "mozilla/Telemetry.h"
@@ -104,7 +105,7 @@ private:
 
 gfxUserFontEntry::gfxUserFontEntry(gfxUserFontSet* aFontSet,
              const nsTArray<gfxFontFaceSrc>& aFontFaceSrcList,
-             uint32_t aWeight,
+             FontWeight aWeight,
              int32_t aStretch,
              uint8_t aStyle,
              const nsTArray<gfxFontFeature>& aFeatureSettings,
@@ -120,8 +121,8 @@ gfxUserFontEntry::gfxUserFontEntry(gfxUserFontSet* aFontSet,
       mLoader(nullptr),
       mFontSet(aFontSet)
 {
-    MOZ_ASSERT(aWeight != 0,
-               "aWeight must not be 0; use NS_FONT_WEIGHT_NORMAL instead");
+    MOZ_ASSERT(aWeight != FontWeight(0),
+               "aWeight must not be 0; use FontWeight::Normal() instead");
     mIsUserFontContainer = true;
     mSrcList = aFontFaceSrcList;
     mSrcIndex = 0;
@@ -144,7 +145,7 @@ gfxUserFontEntry::~gfxUserFontEntry()
 
 bool
 gfxUserFontEntry::Matches(const nsTArray<gfxFontFaceSrc>& aFontFaceSrcList,
-                          uint32_t aWeight,
+                          FontWeight aWeight,
                           int32_t aStretch,
                           uint8_t aStyle,
                           const nsTArray<gfxFontFeature>& aFeatureSettings,
@@ -935,7 +936,7 @@ already_AddRefed<gfxUserFontEntry>
 gfxUserFontSet::FindOrCreateUserFontEntry(
                                const nsAString& aFamilyName,
                                const nsTArray<gfxFontFaceSrc>& aFontFaceSrcList,
-                               uint32_t aWeight,
+                               FontWeight aWeight,
                                int32_t aStretch,
                                uint8_t aStyle,
                                const nsTArray<gfxFontFeature>& aFeatureSettings,
@@ -975,7 +976,7 @@ gfxUserFontSet::FindOrCreateUserFontEntry(
 already_AddRefed<gfxUserFontEntry>
 gfxUserFontSet::CreateUserFontEntry(
                                const nsTArray<gfxFontFaceSrc>& aFontFaceSrcList,
-                               uint32_t aWeight,
+                               FontWeight aWeight,
                                int32_t aStretch,
                                uint8_t aStyle,
                                const nsTArray<gfxFontFeature>& aFeatureSettings,
@@ -996,7 +997,7 @@ gfxUserFontEntry*
 gfxUserFontSet::FindExistingUserFontEntry(
                                gfxUserFontFamily* aFamily,
                                const nsTArray<gfxFontFaceSrc>& aFontFaceSrcList,
-                               uint32_t aWeight,
+                               FontWeight aWeight,
                                int32_t aStretch,
                                uint8_t aStyle,
                                const nsTArray<gfxFontFeature>& aFeatureSettings,
@@ -1005,8 +1006,8 @@ gfxUserFontSet::FindExistingUserFontEntry(
                                gfxCharacterMap* aUnicodeRanges,
                                uint8_t aFontDisplay)
 {
-    MOZ_ASSERT(aWeight != 0,
-               "aWeight must not be 0; use NS_FONT_WEIGHT_NORMAL instead");
+    MOZ_ASSERT(aWeight != FontWeight(0),
+               "aWeight must not be 0; use FontWeight::Normal() instead");
 
     nsTArray<RefPtr<gfxFontEntry>>& fontList = aFamily->GetFontList();
 
@@ -1039,12 +1040,12 @@ gfxUserFontSet::AddUserFontEntry(const nsAString& aFamilyName,
     family->AddFontEntry(aUserFontEntry);
 
     if (LOG_ENABLED()) {
-        LOG(("userfonts (%p) added to \"%s\" (%p) style: %s weight: %d "
+        LOG(("userfonts (%p) added to \"%s\" (%p) style: %s weight: %g "
              "stretch: %d display: %d",
              this, NS_ConvertUTF16toUTF8(aFamilyName).get(), aUserFontEntry,
              (aUserFontEntry->IsItalic() ? "italic" :
               (aUserFontEntry->IsOblique() ? "oblique" : "normal")),
-             aUserFontEntry->Weight(), aUserFontEntry->Stretch(),
+             aUserFontEntry->Weight().ToFloat(), aUserFontEntry->Stretch(),
              aUserFontEntry->GetFontDisplay()));
     }
 }
diff --git a/gfx/thebes/gfxUserFontSet.h b/gfx/thebes/gfxUserFontSet.h
index ef28c0b07b4c..23d607ab7b08 100644
--- a/gfx/thebes/gfxUserFontSet.h
+++ b/gfx/thebes/gfxUserFontSet.h
@@ -16,6 +16,7 @@
 #include "nsIPrincipal.h"
 #include "nsIScriptError.h"
 #include "nsURIHashKey.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/net/ReferrerPolicy.h"
 #include "gfxFontConstants.h"
 
@@ -184,6 +185,7 @@ class gfxUserFontSet {
     friend class gfxOTSContext;
 
 public:
+    typedef mozilla::FontWeight FontWeight;
 
     NS_INLINE_DECL_THREADSAFE_REFCOUNTING(gfxUserFontSet)
 
@@ -229,7 +231,7 @@ public:
     // TODO: support for unicode ranges not yet implemented
     virtual already_AddRefed<gfxUserFontEntry> CreateUserFontEntry(
                               const nsTArray<gfxFontFaceSrc>& aFontFaceSrcList,
-                              uint32_t aWeight,
+                              FontWeight aWeight,
                               int32_t aStretch,
                               uint8_t aStyle,
                               const nsTArray<gfxFontFeature>& aFeatureSettings,
@@ -243,7 +245,7 @@ public:
     already_AddRefed<gfxUserFontEntry> FindOrCreateUserFontEntry(
                                const nsAString& aFamilyName,
                                const nsTArray<gfxFontFaceSrc>& aFontFaceSrcList,
-                               uint32_t aWeight,
+                               FontWeight aWeight,
                                int32_t aStretch,
                                uint8_t aStyle,
                                const nsTArray<gfxFontFeature>& aFeatureSettings,
@@ -404,8 +406,8 @@ public:
                                             HashFeatures(aKey->mFontEntry->mFeatureSettings),
                                             HashVariations(aKey->mFontEntry->mVariationSettings),
                                             mozilla::HashString(aKey->mFontEntry->mFamilyName),
+                                            aKey->mFontEntry->mWeight.ForHash(),
                                             (aKey->mFontEntry->mStyle |
-                                             (aKey->mFontEntry->mWeight << 2) |
                                              (aKey->mFontEntry->mStretch << 11) ) ^
                                              aKey->mFontEntry->mLanguageOverride);
             }
@@ -497,7 +499,7 @@ protected:
     gfxUserFontEntry* FindExistingUserFontEntry(
                                    gfxUserFontFamily* aFamily,
                                    const nsTArray<gfxFontFaceSrc>& aFontFaceSrcList,
-                                   uint32_t aWeight,
+                                   FontWeight aWeight,
                                    int32_t aStretch,
                                    uint8_t aStyle,
                                    const nsTArray<gfxFontFeature>& aFeatureSettings,
@@ -537,6 +539,8 @@ class gfxUserFontEntry : public gfxFontEntry {
     friend class gfxOTSContext;
 
 public:
+    typedef mozilla::FontWeight FontWeight;
+
     enum UserFontLoadState {
         STATUS_NOT_LOADED = 0,
         STATUS_LOAD_PENDING,
@@ -547,7 +551,7 @@ public:
 
     gfxUserFontEntry(gfxUserFontSet* aFontSet,
                      const nsTArray<gfxFontFaceSrc>& aFontFaceSrcList,
-                     uint32_t aWeight,
+                     FontWeight aWeight,
                      int32_t aStretch,
                      uint8_t aStyle,
                      const nsTArray<gfxFontFeature>& aFeatureSettings,
@@ -560,7 +564,7 @@ public:
 
     // Return whether the entry matches the given list of attributes
     bool Matches(const nsTArray<gfxFontFaceSrc>& aFontFaceSrcList,
-                 uint32_t aWeight,
+                 FontWeight aWeight,
                  int32_t aStretch,
                  uint8_t aStyle,
                  const nsTArray<gfxFontFeature>& aFeatureSettings,
diff --git a/gfx/webrender_bindings/RenderThread.cpp b/gfx/webrender_bindings/RenderThread.cpp
index 7bbf8365101f..8a3115dc8e02 100644
--- a/gfx/webrender_bindings/RenderThread.cpp
+++ b/gfx/webrender_bindings/RenderThread.cpp
@@ -100,6 +100,9 @@ RenderThread::ShutDownTask(layers::SynchronousTask* aTask)
 {
   layers::AutoCompleteTask complete(aTask);
   MOZ_ASSERT(IsInRenderThread());
+
+  MutexAutoLock lock(mRenderTextureMapLock);
+  mRenderTextures.Clear();
 }
 
 // static
diff --git a/gfx/webrender_bindings/src/bindings.rs b/gfx/webrender_bindings/src/bindings.rs
index 59a21723aaaf..2978d01734fb 100644
--- a/gfx/webrender_bindings/src/bindings.rs
+++ b/gfx/webrender_bindings/src/bindings.rs
@@ -456,10 +456,9 @@ fn get_proc_address(glcontext_ptr: *mut c_void,
     let symbol_name = CString::new(name).unwrap();
     let symbol = unsafe { get_proc_address_from_glcontext(glcontext_ptr, symbol_name.as_ptr()) };
 
-    // For now panic, not sure we should be though or if we can recover
     if symbol.is_null() {
         // XXX Bug 1322949 Make whitelist for extensions
-        println!("Could not find symbol {:?} by glcontext", symbol_name);
+        warn!("Could not find symbol {:?} by glcontext", symbol_name);
     }
 
     symbol as *const _
@@ -564,7 +563,7 @@ pub extern "C" fn wr_renderer_render(renderer: &mut Renderer,
         Ok(_) => true,
         Err(errors) => {
             for e in errors {
-                println!(" Failed to render: {:?}", e);
+                warn!(" Failed to render: {:?}", e);
                 let msg = CString::new(format!("wr_renderer_render: {:?}", e)).unwrap();
                 unsafe {
                     gfx_critical_note(msg.as_ptr());
@@ -836,7 +835,7 @@ pub extern "C" fn wr_window_new(window_id: WrWindowId,
 
     let version = gl.get_string(gl::VERSION);
 
-    println!("WebRender - OpenGL version new {}", version);
+    info!("WebRender - OpenGL version new {}", version);
 
     let workers = unsafe {
         Arc::clone(&(*thread_pool).0)
@@ -879,7 +878,7 @@ pub extern "C" fn wr_window_new(window_id: WrWindowId,
     let (renderer, sender) = match Renderer::new(gl, notifier, opts) {
         Ok((renderer, sender)) => (renderer, sender),
         Err(e) => {
-            println!(" Failed to create a Renderer: {:?}", e);
+            warn!(" Failed to create a Renderer: {:?}", e);
             let msg = CString::new(format!("wr_window_new: {:?}", e)).unwrap();
             unsafe {
                 gfx_critical_note(msg.as_ptr());
@@ -1323,7 +1322,7 @@ pub extern "C" fn wr_api_capture(
             file.write(revision).unwrap();
         }
         Err(e) => {
-            println!("Unable to create path '{:?}' for capture: {:?}", path, e);
+            warn!("Unable to create path '{:?}' for capture: {:?}", path, e);
             return
         }
     }
diff --git a/gfx/webrender_bindings/src/lib.rs b/gfx/webrender_bindings/src/lib.rs
index 5ffa18e37da3..426d28b21da7 100644
--- a/gfx/webrender_bindings/src/lib.rs
+++ b/gfx/webrender_bindings/src/lib.rs
@@ -10,6 +10,8 @@ extern crate app_units;
 extern crate gleam;
 extern crate rayon;
 extern crate thread_profiler;
+
+#[macro_use]
 extern crate log;
 
 #[cfg(target_os = "windows")]
diff --git a/image/AnimationFrameBuffer.cpp b/image/AnimationFrameBuffer.cpp
index 31ce5b103e50..5d8b672f6665 100644
--- a/image/AnimationFrameBuffer.cpp
+++ b/image/AnimationFrameBuffer.cpp
@@ -17,6 +17,7 @@ AnimationFrameBuffer::AnimationFrameBuffer()
   , mInsertIndex(0)
   , mGetIndex(0)
   , mSizeKnown(false)
+  , mRedecodeError(false)
 { }
 
 void
@@ -71,7 +72,16 @@ AnimationFrameBuffer::Insert(RawAccessFrameRef&& aFrame)
     // and we did not keep all of the frames. Replace whatever is there
     // (probably an empty frame) with the new frame.
     MOZ_ASSERT(MayDiscard());
-    MOZ_ASSERT(mInsertIndex < mFrames.Length());
+
+    // The first decode produced fewer frames than the redecodes, presumably
+    // because it hit an out-of-memory error which later attempts avoided. Just
+    // stop the animation because we can't tell the image that we have more
+    // frames now.
+    if (mInsertIndex >= mFrames.Length()) {
+      mRedecodeError = true;
+      mPending = 0;
+      return false;
+    }
 
     if (mInsertIndex > 0) {
       MOZ_ASSERT(!mFrames[mInsertIndex]);
@@ -127,9 +137,23 @@ AnimationFrameBuffer::Insert(RawAccessFrameRef&& aFrame)
 bool
 AnimationFrameBuffer::MarkComplete()
 {
+  // We may have stopped decoding at a different point in the animation than we
+  // did previously. That means the decoder likely hit a new error, e.g. OOM.
+  // This will prevent us from advancing as well, because we are missing the
+  // required frames to blend.
+  //
+  // XXX(aosmond): In an ideal world, we would be generating full frames, and
+  // the consumer of our data doesn't care about our internal state. It simply
+  // knows about the first frame, the current frame, and how long to display the
+  // current frame.
+  if (NS_WARN_IF(mInsertIndex != mFrames.Length())) {
+    MOZ_ASSERT(mSizeKnown);
+    mRedecodeError = true;
+    mPending = 0;
+  }
+
   // We reached the end of the animation, the next frame we get, if we get
   // another, will be the first frame again.
-  MOZ_ASSERT(mInsertIndex == mFrames.Length());
   mInsertIndex = 0;
 
   // Since we only request advancing when we want to resume at a certain point
@@ -231,7 +255,7 @@ AnimationFrameBuffer::AdvanceInternal()
     }
   }
 
-  if (!mSizeKnown || MayDiscard()) {
+  if (!mRedecodeError && (!mSizeKnown || MayDiscard())) {
     // Calculate how many frames we have requested ahead of the current frame.
     size_t buffered = mPending;
     if (mGetIndex > mInsertIndex) {
@@ -276,13 +300,6 @@ AnimationFrameBuffer::Reset()
     return false;
   }
 
-  // If we are over the threshold, then we know we will have missing frames in
-  // our buffer. The easiest thing to do is to drop everything but the first
-  // frame and go back to the initial state.
-  bool restartDecoder = mPending == 0;
-  mInsertIndex = 0;
-  mPending = 2 * mBatch;
-
   // Discard all frames besides the first, because the decoder always expects
   // that when it re-inserts a frame, it is not present. (It doesn't re-insert
   // the first frame.)
@@ -290,6 +307,16 @@ AnimationFrameBuffer::Reset()
     RawAccessFrameRef discard = Move(mFrames[i]);
   }
 
+  mInsertIndex = 0;
+
+  // If we hit an error after redecoding, we never want to restart decoding.
+  if (mRedecodeError) {
+    MOZ_ASSERT(mPending == 0);
+    return false;
+  }
+
+  bool restartDecoder = mPending == 0;
+  mPending = 2 * mBatch;
   return restartDecoder;
 }
 
diff --git a/image/AnimationFrameBuffer.h b/image/AnimationFrameBuffer.h
index 0ad94aebe57f..aa23327e9186 100644
--- a/image/AnimationFrameBuffer.h
+++ b/image/AnimationFrameBuffer.h
@@ -129,6 +129,12 @@ public:
    */
   bool SizeKnown() const { return mSizeKnown; }
 
+  /**
+   * @returns True if encountered an error during redecode which should cause
+   *          the caller to stop inserting frames.
+   */
+  bool HasRedecodeError() const { return mRedecodeError; }
+
   /**
    * @returns The current frame index we have advanced to.
    */
@@ -187,6 +193,9 @@ private:
 
   // True if the total number of frames is known.
   bool mSizeKnown;
+
+  // True if we encountered an error while redecoding.
+  bool mRedecodeError;
 };
 
 } // namespace image
diff --git a/image/AnimationSurfaceProvider.cpp b/image/AnimationSurfaceProvider.cpp
index 4ff055e57534..4eeac1d852f2 100644
--- a/image/AnimationSurfaceProvider.cpp
+++ b/image/AnimationSurfaceProvider.cpp
@@ -224,13 +224,14 @@ AnimationSurfaceProvider::Run()
       FinishDecoding();
 
       // Even if it is the last frame, we may not have enough frames buffered
-      // ahead of the current.
-      if (continueDecoding) {
-        MOZ_ASSERT(mDecoder);
-        continue;
+      // ahead of the current. If we are shutting down, we want to ensure we
+      // release the thread as soon as possible. The animation may advance even
+      // during shutdown, which keeps us decoding, and thus blocking the decode
+      // pool during teardown.
+      if (!mDecoder || !continueDecoding ||
+          DecodePool::Singleton()->IsShuttingDown()) {
+        return;
       }
-
-      return;
     }
 
     // Notify for the progress we've made so far.
@@ -245,9 +246,13 @@ AnimationSurfaceProvider::Run()
     }
 
     // There's new output available - a new frame! Grab it. If we don't need any
-    // more for the moment we can break out of the loop.
+    // more for the moment we can break out of the loop. If we are shutting
+    // down, we want to ensure we release the thread as soon as possible. The
+    // animation may advance even during shutdown, which keeps us decoding, and
+    // thus blocking the decode pool during teardown.
     MOZ_ASSERT(result == LexerResult(Yield::OUTPUT_AVAILABLE));
-    if (!CheckForNewFrameAtYield()) {
+    if (!CheckForNewFrameAtYield() ||
+        DecodePool::Singleton()->IsShuttingDown()) {
       return;
     }
   }
@@ -294,10 +299,7 @@ AnimationSurfaceProvider::CheckForNewFrameAtYield()
     AnnounceSurfaceAvailable();
   }
 
-  // If we are shutting down, we want to ensure we release the thread as soon
-  // as possible. The animation may advance even during shutdown, which keeps
-  // us decoding, and thus blocking the decode pool during teardown.
-  return continueDecoding && !DecodePool::Singleton()->IsShuttingDown();
+  return continueDecoding;
 }
 
 bool
@@ -347,10 +349,7 @@ AnimationSurfaceProvider::CheckForNewFrameAtTerminalState()
     AnnounceSurfaceAvailable();
   }
 
-  // If we are shutting down, we want to ensure we release the thread as soon
-  // as possible. The animation may advance even during shutdown, which keeps
-  // us decoding, and thus blocking the decode pool during teardown.
-  return continueDecoding && !DecodePool::Singleton()->IsShuttingDown();
+  return continueDecoding;
 }
 
 void
@@ -378,15 +377,15 @@ AnimationSurfaceProvider::FinishDecoding()
     NotifyDecodeComplete(WrapNotNull(mImage), WrapNotNull(mDecoder));
   }
 
-  // Destroy our decoder; we don't need it anymore.
-  bool mayDiscard;
+  // Determine if we need to recreate the decoder, in case we are discarding
+  // frames and need to loop back to the beginning.
+  bool recreateDecoder;
   {
     MutexAutoLock lock(mFramesMutex);
-    mayDiscard = mFrames.MayDiscard();
+    recreateDecoder = !mFrames.HasRedecodeError() && mFrames.MayDiscard();
   }
 
-  if (mayDiscard) {
-    // Recreate the decoder so we can regenerate the frames again.
+  if (recreateDecoder) {
     mDecoder = DecoderFactory::CloneAnimationDecoder(mDecoder);
     MOZ_ASSERT(mDecoder);
   } else {
diff --git a/image/test/gtest/TestAnimationFrameBuffer.cpp b/image/test/gtest/TestAnimationFrameBuffer.cpp
index 55743ebdb1e7..e8fc495cc6da 100644
--- a/image/test/gtest/TestAnimationFrameBuffer.cpp
+++ b/image/test/gtest/TestAnimationFrameBuffer.cpp
@@ -143,6 +143,7 @@ TEST_F(ImageAnimationFrameBuffer, FinishUnderBatchAndThreshold)
       EXPECT_FALSE(keepDecoding);
       EXPECT_TRUE(buffer.SizeKnown());
       EXPECT_EQ(size_t(0), buffer.PendingDecode());
+      EXPECT_FALSE(buffer.HasRedecodeError());
     }
 
     EXPECT_FALSE(buffer.MayDiscard());
@@ -220,6 +221,7 @@ TEST_F(ImageAnimationFrameBuffer, FinishMultipleBatchesUnderThreshold)
   EXPECT_TRUE(buffer.SizeKnown());
   EXPECT_EQ(size_t(0), buffer.PendingDecode());
   EXPECT_EQ(size_t(5), frames.Length());
+  EXPECT_FALSE(buffer.HasRedecodeError());
 
   // Finish progressing through the animation.
   for ( ; i < frames.Length(); ++i) {
@@ -330,6 +332,7 @@ TEST_F(ImageAnimationFrameBuffer, MayDiscard)
   EXPECT_TRUE(buffer.SizeKnown());
   EXPECT_EQ(size_t(2), buffer.PendingDecode());
   EXPECT_EQ(size_t(10), frames.Length());
+  EXPECT_FALSE(buffer.HasRedecodeError());
 
   // Use remaining pending room. It shouldn't add new frames, only replace.
   do {
@@ -513,3 +516,159 @@ TEST_F(ImageAnimationFrameBuffer, StartAfterBeginningAndReset)
   EXPECT_EQ(size_t(0), buffer.PendingAdvance());
 }
 
+TEST_F(ImageAnimationFrameBuffer, RedecodeMoreFrames)
+{
+  const size_t kThreshold = 5;
+  const size_t kBatch = 2;
+  AnimationFrameBuffer buffer;
+  buffer.Initialize(kThreshold, kBatch, 0);
+  const auto& frames = buffer.Frames();
+
+  // Add frames until we exceed the threshold.
+  bool keepDecoding;
+  bool restartDecoder;
+  size_t i = 0;
+  do {
+    keepDecoding = buffer.Insert(CreateEmptyFrame());
+    EXPECT_TRUE(keepDecoding);
+    if (i > 0) {
+      restartDecoder = buffer.AdvanceTo(i);
+      EXPECT_FALSE(restartDecoder);
+    }
+    ++i;
+  } while (!buffer.MayDiscard());
+
+  // Should have threshold + 1 frames, and still not complete.
+  EXPECT_EQ(size_t(6), frames.Length());
+  EXPECT_FALSE(buffer.SizeKnown());
+
+  // Now we lock in at 6 frames.
+  keepDecoding = buffer.MarkComplete();
+  EXPECT_TRUE(keepDecoding);
+  EXPECT_TRUE(buffer.SizeKnown());
+  EXPECT_FALSE(buffer.HasRedecodeError());
+
+  // Reinsert 6 frames first.
+  i = 0;
+  do {
+    keepDecoding = buffer.Insert(CreateEmptyFrame());
+    EXPECT_TRUE(keepDecoding);
+    restartDecoder = buffer.AdvanceTo(i);
+    EXPECT_FALSE(restartDecoder);
+    ++i;
+  } while (i < 6);
+
+  // We should now encounter an error and shutdown further decodes.
+  keepDecoding = buffer.Insert(CreateEmptyFrame());
+  EXPECT_FALSE(keepDecoding);
+  EXPECT_EQ(size_t(0), buffer.PendingDecode());
+  EXPECT_TRUE(buffer.HasRedecodeError());
+}
+
+TEST_F(ImageAnimationFrameBuffer, RedecodeFewerFrames)
+{
+  const size_t kThreshold = 5;
+  const size_t kBatch = 2;
+  AnimationFrameBuffer buffer;
+  buffer.Initialize(kThreshold, kBatch, 0);
+  const auto& frames = buffer.Frames();
+
+  // Add frames until we exceed the threshold.
+  bool keepDecoding;
+  bool restartDecoder;
+  size_t i = 0;
+  do {
+    keepDecoding = buffer.Insert(CreateEmptyFrame());
+    EXPECT_TRUE(keepDecoding);
+    if (i > 0) {
+      restartDecoder = buffer.AdvanceTo(i);
+      EXPECT_FALSE(restartDecoder);
+    }
+    ++i;
+  } while (!buffer.MayDiscard());
+
+  // Should have threshold + 1 frames, and still not complete.
+  EXPECT_EQ(size_t(6), frames.Length());
+  EXPECT_FALSE(buffer.SizeKnown());
+
+  // Now we lock in at 6 frames.
+  keepDecoding = buffer.MarkComplete();
+  EXPECT_TRUE(keepDecoding);
+  EXPECT_TRUE(buffer.SizeKnown());
+  EXPECT_FALSE(buffer.HasRedecodeError());
+
+  // Reinsert 5 frames before marking complete.
+  i = 0;
+  do {
+    keepDecoding = buffer.Insert(CreateEmptyFrame());
+    EXPECT_TRUE(keepDecoding);
+    restartDecoder = buffer.AdvanceTo(i);
+    EXPECT_FALSE(restartDecoder);
+    ++i;
+  } while (i < 5);
+
+  // We should now encounter an error and shutdown further decodes.
+  keepDecoding = buffer.MarkComplete();
+  EXPECT_FALSE(keepDecoding);
+  EXPECT_EQ(size_t(0), buffer.PendingDecode());
+  EXPECT_TRUE(buffer.HasRedecodeError());
+}
+
+TEST_F(ImageAnimationFrameBuffer, RedecodeFewerFramesAndBehindAdvancing)
+{
+  const size_t kThreshold = 5;
+  const size_t kBatch = 2;
+  AnimationFrameBuffer buffer;
+  buffer.Initialize(kThreshold, kBatch, 0);
+  const auto& frames = buffer.Frames();
+
+  // Add frames until we exceed the threshold.
+  bool keepDecoding;
+  bool restartDecoder;
+  size_t i = 0;
+  do {
+    keepDecoding = buffer.Insert(CreateEmptyFrame());
+    EXPECT_TRUE(keepDecoding);
+    if (i > 0) {
+      restartDecoder = buffer.AdvanceTo(i);
+      EXPECT_FALSE(restartDecoder);
+    }
+    ++i;
+  } while (!buffer.MayDiscard());
+
+  // Should have threshold + 1 frames, and still not complete.
+  EXPECT_EQ(size_t(6), frames.Length());
+  EXPECT_FALSE(buffer.SizeKnown());
+
+  // Now we lock in at 6 frames.
+  keepDecoding = buffer.MarkComplete();
+  EXPECT_TRUE(keepDecoding);
+  EXPECT_TRUE(buffer.SizeKnown());
+  EXPECT_FALSE(buffer.HasRedecodeError());
+
+  // Reinsert frames without advancing until we exhaust our pending space. This
+  // should be less than the current buffer length by definition.
+  i = 0;
+  do {
+    keepDecoding = buffer.Insert(CreateEmptyFrame());
+    ++i;
+  } while (keepDecoding);
+
+  EXPECT_EQ(size_t(2), i);
+
+  // We should now encounter an error and shutdown further decodes.
+  keepDecoding = buffer.MarkComplete();
+  EXPECT_FALSE(keepDecoding);
+  EXPECT_EQ(size_t(0), buffer.PendingDecode());
+  EXPECT_TRUE(buffer.HasRedecodeError());
+
+  // We should however be able to continue advancing to the last decoded frame
+  // without it requesting the decoder to restart.
+  i = 0;
+  do {
+    restartDecoder = buffer.AdvanceTo(i);
+    EXPECT_FALSE(restartDecoder);
+    ++i;
+  } while (i < 2);
+}
+
diff --git a/js/src/builtin/TestingFunctions.cpp b/js/src/builtin/TestingFunctions.cpp
index ad9afc1190ab..fc7988285b9f 100644
--- a/js/src/builtin/TestingFunctions.cpp
+++ b/js/src/builtin/TestingFunctions.cpp
@@ -587,6 +587,19 @@ WasmSaturatingTruncationSupported(JSContext* cx, unsigned argc, Value* vp)
     return true;
 }
 
+static bool
+WasmGcEnabled(JSContext* cx, unsigned argc, Value* vp)
+{
+    CallArgs args = CallArgsFromVp(argc, vp);
+#ifdef ENABLE_WASM_GC
+    bool isSupported = cx->options().wasmBaseline() && cx->options().wasmGc();
+#else
+    bool isSupported = false;
+#endif
+    args.rval().setBoolean(isSupported);
+    return true;
+}
+
 static bool
 WasmCompileMode(JSContext* cx, unsigned argc, Value* vp)
 {
@@ -5503,6 +5516,10 @@ gc::ZealModeHelpText),
 "  Returns a boolean indicating whether a given module has finished compiled code for tier2. \n"
 "This will return true early if compilation isn't two-tiered. "),
 
+    JS_FN_HELP("wasmGcEnabled", WasmGcEnabled, 1, 0,
+"wasmGcEnabled(bool)",
+"  Returns a boolean indicating whether the WebAssembly GC support is enabled."),
+
     JS_FN_HELP("isLazyFunction", IsLazyFunction, 1, 0,
 "isLazyFunction(fun)",
 "  True if fun is a lazy JSFunction."),
diff --git a/js/src/jit-test/tests/wasm/gc/anyref.js b/js/src/jit-test/tests/wasm/gc/anyref.js
new file mode 100644
index 000000000000..d06b2154755a
--- /dev/null
+++ b/js/src/jit-test/tests/wasm/gc/anyref.js
@@ -0,0 +1,383 @@
+// Ensure that if gc types aren't enabled, test cases properly fail.
+
+if (!wasmGcEnabled()) {
+    quit(0);
+}
+
+// Dummy constructor.
+function Baguette(calories) {
+    this.calories = calories;
+}
+
+// Type checking.
+
+const { validate, CompileError } = WebAssembly;
+
+assertErrorMessage(() => wasmEvalText(`(module
+    (func (result anyref)
+        i32.const 42
+    )
+)`), CompileError, mismatchError('i32', 'anyref'));
+
+assertErrorMessage(() => wasmEvalText(`(module
+    (func (result anyref)
+        i32.const 0
+        ref.null anyref
+        i32.const 42
+        select
+    )
+)`), CompileError, /select operand types/);
+
+assertErrorMessage(() => wasmEvalText(`(module
+    (func (result i32)
+        ref.null anyref
+        if
+            i32.const 42
+        end
+    )
+)`), CompileError, mismatchError('anyref', 'i32'));
+
+
+// Basic compilation tests.
+
+let simpleTests = [
+    "(module (func (drop (ref.null anyref))))",
+    "(module (func $test (local anyref)))",
+    "(module (func $test (param anyref)))",
+    "(module (func $test (result anyref) (ref.null anyref)))",
+    "(module (func $test (block anyref (unreachable)) unreachable))",
+    "(module (func $test (local anyref) (result i32) (ref.is_null (get_local 0))))",
+    `(module (import "a" "b" (param anyref)))`,
+    `(module (import "a" "b" (result anyref)))`,
+];
+
+for (let src of simpleTests) {
+    wasmEvalText(src, {a:{b(){}}});
+    assertEq(validate(wasmTextToBinary(src)), true);
+}
+
+// Basic behavioral tests.
+
+let { exports } = wasmEvalText(`(module
+    (func (export "is_null") (result i32)
+        ref.null anyref
+        ref.is_null
+    )
+
+    (func $sum (result i32) (param i32)
+        get_local 0
+        i32.const 42
+        i32.add
+    )
+
+    (func (export "is_null_spill") (result i32)
+        ref.null anyref
+        i32.const 58
+        call $sum
+        drop
+        ref.is_null
+    )
+
+    (func (export "is_null_local") (result i32) (local anyref)
+        ref.null anyref
+        set_local 0
+        i32.const 58
+        call $sum
+        drop
+        get_local 0
+        ref.is_null
+    )
+)`);
+
+assertEq(exports.is_null(), 1);
+assertEq(exports.is_null_spill(), 1);
+assertEq(exports.is_null_local(), 1);
+
+// Anyref param and result in wasm functions.
+
+exports = wasmEvalText(`(module
+    (func (export "is_null") (result i32) (param $ref anyref)
+        get_local $ref
+        ref.is_null
+    )
+
+    (func (export "ref_or_null") (result anyref) (param $ref anyref) (param $selector i32)
+        get_local $ref
+        ref.null anyref
+        get_local $selector
+        select
+    )
+
+    (func $recursive (export "nested") (result anyref) (param $ref anyref) (param $i i32)
+        ;; i == 10 => ret $ref
+        get_local $i
+        i32.const 10
+        i32.eq
+        if
+            get_local $ref
+            return
+        end
+
+        get_local $ref
+
+        get_local $i
+        i32.const 1
+        i32.add
+
+        call $recursive
+    )
+)`).exports;
+
+assertErrorMessage(() => exports.is_null(undefined), TypeError, "can't convert undefined to object");
+assertEq(exports.is_null(null), 1);
+assertEq(exports.is_null({}), 0);
+assertEq(exports.is_null("hi"), 0);
+assertEq(exports.is_null(3), 0);
+assertEq(exports.is_null(3.5), 0);
+assertEq(exports.is_null(true), 0);
+assertEq(exports.is_null(Symbol("croissant")), 0);
+assertEq(exports.is_null(new Baguette(100)), 0);
+
+let baguette = new Baguette(42);
+assertEq(exports.ref_or_null(null, 0), null);
+assertEq(exports.ref_or_null(baguette, 0), null);
+
+let ref = exports.ref_or_null(baguette, 1);
+assertEq(ref, baguette);
+assertEq(ref.calories, baguette.calories);
+
+ref = exports.nested(baguette, 0);
+assertEq(ref, baguette);
+assertEq(ref.calories, baguette.calories);
+
+// More interesting use cases about control flow joins.
+
+function assertJoin(body) {
+    let val = { i: -1 };
+    assertEq(wasmEvalText(`(module
+        (func (export "test") (param $ref anyref) (param $i i32) (result anyref)
+            ${body}
+        )
+    )`).exports.test(val), val);
+    assertEq(val.i, -1);
+}
+
+assertJoin("(block anyref get_local $ref)");
+assertJoin("(block $out anyref get_local $ref br $out)");
+assertJoin("(loop anyref get_local $ref)");
+
+assertJoin(`(block $out anyref (loop $top anyref
+    get_local $i
+    i32.const 1
+    i32.add
+    tee_local $i
+    i32.const 10
+    i32.eq
+    if
+        get_local $ref
+        return
+    end
+    br $top))
+`);
+
+assertJoin(`(block $out (loop $top
+    get_local $i
+    i32.const 1
+    i32.add
+    tee_local $i
+    i32.const 10
+    i32.le_s
+    if
+        br $top
+    else
+        get_local $ref
+        return
+    end
+    )) unreachable
+`);
+
+assertJoin(`(block $out anyref (loop $top
+    get_local $ref
+    get_local $i
+    i32.const 1
+    i32.add
+    tee_local $i
+    i32.const 10
+    i32.eq
+    br_if $out
+    br $top
+    ) unreachable)
+`);
+
+assertJoin(`(block $out anyref (block $unreachable anyref (loop $top
+    get_local $ref
+    get_local $i
+    i32.const 1
+    i32.add
+    tee_local $i
+    br_table $unreachable $out
+    ) unreachable))
+`);
+
+let x = { i: 42 }, y = { f: 53 };
+exports = wasmEvalText(`(module
+    (func (export "test") (param $lhs anyref) (param $rhs anyref) (param $i i32) (result anyref)
+        get_local $lhs
+        get_local $rhs
+        get_local $i
+        select
+    )
+)`).exports;
+
+let result = exports.test(x, y, 0);
+assertEq(result, y);
+assertEq(result.i, undefined);
+assertEq(result.f, 53);
+assertEq(x.i, 42);
+
+result = exports.test(x, y, 1);
+assertEq(result, x);
+assertEq(result.i, 42);
+assertEq(result.f, undefined);
+assertEq(y.f, 53);
+
+// Anyref in params/result of imported functions.
+
+let firstBaguette = new Baguette(13),
+    secondBaguette = new Baguette(37);
+
+let imports = {
+    i: 0,
+    myBaguette: null,
+    funcs: {
+        param(x) {
+            if (this.i === 0) {
+                assertEq(x, firstBaguette);
+                assertEq(x.calories, 13);
+                assertEq(secondBaguette !== null, true);
+            } else if (this.i === 1 || this.i === 2) {
+                assertEq(x, secondBaguette);
+                assertEq(x.calories, 37);
+                assertEq(firstBaguette !== null, true);
+            } else if (this.i === 3) {
+                assertEq(x, null);
+            } else {
+                firstBaguette = null;
+                secondBaguette = null;
+                gc(); // evil mode
+            }
+            this.i++;
+        },
+        ret() {
+            return imports.myBaguette;
+        }
+    }
+};
+
+exports = wasmEvalText(`(module
+    (import $ret "funcs" "ret" (result anyref))
+    (import $param "funcs" "param" (param anyref))
+
+    (func (export "param") (param $x anyref) (param $y anyref)
+        get_local $y
+        get_local $x
+        call $param
+        call $param
+    )
+
+    (func (export "ret") (result anyref)
+        call $ret
+    )
+)`, imports).exports;
+
+exports.param(firstBaguette, secondBaguette);
+exports.param(secondBaguette, null);
+exports.param(firstBaguette, secondBaguette);
+
+imports.myBaguette = null;
+assertEq(exports.ret(), null);
+
+imports.myBaguette = new Baguette(1337);
+assertEq(exports.ret(), imports.myBaguette);
+
+// Check lazy stubs generation.
+
+exports = wasmEvalText(`(module
+    (import $mirror "funcs" "mirror" (param anyref) (result anyref))
+    (import $augment "funcs" "augment" (param anyref) (result anyref))
+
+    (global $count_f (mut i32) (i32.const 0))
+    (global $count_g (mut i32) (i32.const 0))
+
+    (func $f (param $param anyref) (result anyref)
+        i32.const 1
+        get_global $count_f
+        i32.add
+        set_global $count_f
+
+        get_local $param
+        call $augment
+    )
+
+    (func $g (param $param anyref) (result anyref)
+        i32.const 1
+        get_global $count_g
+        i32.add
+        set_global $count_g
+
+        get_local $param
+        call $mirror
+    )
+
+    (table (export "table") 10 anyfunc)
+    (elem (i32.const 0) $f $g $mirror $augment)
+    (type $table_type (func (param anyref) (result anyref)))
+
+    (func (export "call_indirect") (param $i i32) (param $ref anyref) (result anyref)
+        get_local $ref
+        get_local $i
+        call_indirect $table_type
+    )
+
+    (func (export "count_f") (result i32) get_global $count_f)
+    (func (export "count_g") (result i32) get_global $count_g)
+)`, {
+    funcs: {
+        mirror(x) {
+            return x;
+        },
+        augment(x) {
+            x.i++;
+            x.newProp = "hello";
+            return x;
+        }
+    }
+}).exports;
+
+x = { i: 19 };
+assertEq(exports.table.get(0)(x), x);
+assertEq(x.i, 20);
+assertEq(x.newProp, "hello");
+assertEq(exports.count_f(), 1);
+assertEq(exports.count_g(), 0);
+
+x = { i: 21 };
+assertEq(exports.table.get(1)(x), x);
+assertEq(x.i, 21);
+assertEq(typeof x.newProp, "undefined");
+assertEq(exports.count_f(), 1);
+assertEq(exports.count_g(), 1);
+
+x = { i: 22 };
+assertEq(exports.table.get(2)(x), x);
+assertEq(x.i, 22);
+assertEq(typeof x.newProp, "undefined");
+assertEq(exports.count_f(), 1);
+assertEq(exports.count_g(), 1);
+
+x = { i: 23 };
+assertEq(exports.table.get(3)(x), x);
+assertEq(x.i, 24);
+assertEq(x.newProp, "hello");
+assertEq(exports.count_f(), 1);
+assertEq(exports.count_g(), 1);
diff --git a/js/src/jit-test/tests/wasm/gc/directives.txt b/js/src/jit-test/tests/wasm/gc/directives.txt
new file mode 100644
index 000000000000..8b0167509cf9
--- /dev/null
+++ b/js/src/jit-test/tests/wasm/gc/directives.txt
@@ -0,0 +1 @@
+|jit-test| test-also=--wasm-gc; include:wasm.js
diff --git a/js/src/jit-test/tests/wasm/gc/disabled.js b/js/src/jit-test/tests/wasm/gc/disabled.js
new file mode 100644
index 000000000000..f720b515ee32
--- /dev/null
+++ b/js/src/jit-test/tests/wasm/gc/disabled.js
@@ -0,0 +1,28 @@
+if (wasmGcEnabled()) {
+    quit();
+}
+
+const { CompileError, validate } = WebAssembly;
+
+const UNRECOGNIZED_OPCODE_OR_BAD_TYPE = /(unrecognized opcode|bad type|invalid inline block type)/;
+
+function assertValidateError(text) {
+    assertEq(validate(wasmTextToBinary(text)), false);
+}
+
+let simpleTests = [
+    "(module (func (drop (ref.null anyref))))",
+    "(module (func $test (local anyref)))",
+    "(module (func $test (param anyref)))",
+    "(module (func $test (result anyref) (ref.null anyref)))",
+    "(module (func $test (block anyref (unreachable)) unreachable))",
+    "(module (func $test (local anyref) (result i32) (ref.is_null (get_local 0))))",
+    `(module (import "a" "b" (param anyref)))`,
+    `(module (import "a" "b" (result anyref)))`,
+];
+
+for (let src of simpleTests) {
+    print(src)
+    assertErrorMessage(() => wasmEvalText(src), CompileError, UNRECOGNIZED_OPCODE_OR_BAD_TYPE);
+    assertValidateError(src);
+}
diff --git a/js/src/jit/IonTypes.h b/js/src/jit/IonTypes.h
index 81d0138e7c62..fca7ca012366 100644
--- a/js/src/jit/IonTypes.h
+++ b/js/src/jit/IonTypes.h
@@ -568,6 +568,8 @@ MIRTypeToSize(MIRType type)
         return 4;
       case MIRType::Double:
         return 8;
+      case MIRType::Pointer:
+        return sizeof(uintptr_t);
       default:
         MOZ_CRASH("MIRTypeToSize - unhandled case");
     }
diff --git a/js/src/jsapi.h b/js/src/jsapi.h
index 96e8f7fc9e7e..8a92381a0307 100644
--- a/js/src/jsapi.h
+++ b/js/src/jsapi.h
@@ -935,6 +935,9 @@ class JS_PUBLIC_API(ContextOptions) {
         wasm_(true),
         wasmBaseline_(true),
         wasmIon_(true),
+#ifdef ENABLE_WASM_GC
+        wasmGc_(false),
+#endif
         testWasmAwaitTier2_(false),
         throwOnAsmJSValidationFailure_(false),
         nativeRegExp_(true),
@@ -1032,6 +1035,14 @@ class JS_PUBLIC_API(ContextOptions) {
         return *this;
     }
 
+#ifdef ENABLE_WASM_GC
+    bool wasmGc() const { return wasmGc_; }
+    ContextOptions& setWasmGc(bool flag) {
+        wasmGc_ = flag;
+        return *this;
+    }
+#endif
+
     bool throwOnAsmJSValidationFailure() const { return throwOnAsmJSValidationFailure_; }
     ContextOptions& setThrowOnAsmJSValidationFailure(bool flag) {
         throwOnAsmJSValidationFailure_ = flag;
@@ -1117,6 +1128,9 @@ class JS_PUBLIC_API(ContextOptions) {
         setWasm(false);
         setWasmBaseline(false);
         setWasmIon(false);
+#ifdef ENABLE_WASM_GC
+        setWasmGc(false);
+#endif
         setNativeRegExp(false);
     }
 
@@ -1127,6 +1141,9 @@ class JS_PUBLIC_API(ContextOptions) {
     bool wasm_ : 1;
     bool wasmBaseline_ : 1;
     bool wasmIon_ : 1;
+#ifdef ENABLE_WASM_GC
+    bool wasmGc_ : 1;
+#endif
     bool testWasmAwaitTier2_ : 1;
     bool throwOnAsmJSValidationFailure_ : 1;
     bool nativeRegExp_ : 1;
diff --git a/js/src/moz.build b/js/src/moz.build
index 0bed1b0e01c3..34a9afd74037 100755
--- a/js/src/moz.build
+++ b/js/src/moz.build
@@ -695,6 +695,7 @@ if CONFIG['NIGHTLY_BUILD']:
     DEFINES['ENABLE_WASM_SATURATING_TRUNC_OPS'] = True
     DEFINES['ENABLE_WASM_SIGNEXTEND_OPS'] = True
     DEFINES['ENABLE_WASM_THREAD_OPS'] = True
+    DEFINES['ENABLE_WASM_GC'] = True
 
 # An experiment we want to run on Nightly and early Beta: Can we change the JS
 # representation of an exported global from the global's value to an instance
diff --git a/js/src/shell/js.cpp b/js/src/shell/js.cpp
index 1e93ac29df52..11f1281e54fc 100644
--- a/js/src/shell/js.cpp
+++ b/js/src/shell/js.cpp
@@ -482,6 +482,9 @@ static bool enableNativeRegExp = false;
 static bool enableSharedMemory = SHARED_MEMORY_DEFAULT;
 static bool enableWasmBaseline = false;
 static bool enableWasmIon = false;
+#ifdef ENABLE_WASM_GC
+static bool enableWasmGc = false;
+#endif
 static bool enableTestWasmAwaitTier2 = false;
 static bool enableAsyncStacks = false;
 static bool enableStreams = false;
@@ -8295,6 +8298,9 @@ SetContextOptions(JSContext* cx, const OptionParser& op)
     enableNativeRegExp = !op.getBoolOption("no-native-regexp");
     enableWasmBaseline = !op.getBoolOption("no-wasm-baseline");
     enableWasmIon = !op.getBoolOption("no-wasm-ion");
+#ifdef ENABLE_WASM_GC
+    enableWasmGc = op.getBoolOption("wasm-gc");
+#endif
     enableTestWasmAwaitTier2 = op.getBoolOption("test-wasm-await-tier2");
     enableAsyncStacks = !op.getBoolOption("no-async-stacks");
     enableStreams = op.getBoolOption("enable-streams");
@@ -8306,6 +8312,9 @@ SetContextOptions(JSContext* cx, const OptionParser& op)
                              .setWasm(enableWasm)
                              .setWasmBaseline(enableWasmBaseline)
                              .setWasmIon(enableWasmIon)
+#ifdef ENABLE_WASM_GC
+                             .setWasmGc(enableWasmGc)
+#endif
                              .setTestWasmAwaitTier2(enableTestWasmAwaitTier2)
                              .setNativeRegExp(enableNativeRegExp)
                              .setAsyncStack(enableAsyncStacks)
@@ -8608,6 +8617,9 @@ SetWorkerContextOptions(JSContext* cx)
                              .setWasm(enableWasm)
                              .setWasmBaseline(enableWasmBaseline)
                              .setWasmIon(enableWasmIon)
+#ifdef ENABLE_WASM_GC
+                             .setWasmGc(enableWasmGc)
+#endif
                              .setTestWasmAwaitTier2(enableTestWasmAwaitTier2)
                              .setNativeRegExp(enableNativeRegExp)
                              .setStreams(enableStreams)
@@ -8851,6 +8863,9 @@ main(int argc, char** argv, char** envp)
         || !op.addBoolOption('\0', "no-wasm-ion", "Disable wasm ion compiler")
         || !op.addBoolOption('\0', "test-wasm-await-tier2", "Forcibly activate tiering and block "
                                    "instantiation on completion of tier2")
+#ifdef ENABLE_WASM_GC
+        || !op.addBoolOption('\0', "wasm-gc", "Enable wasm GC features")
+#endif
         || !op.addBoolOption('\0', "no-native-regexp", "Disable native regexp compilation")
         || !op.addBoolOption('\0', "no-unboxed-objects", "Disable creating unboxed plain objects")
         || !op.addBoolOption('\0', "enable-streams", "Enable WHATWG Streams")
diff --git a/js/src/shell/moz.build b/js/src/shell/moz.build
index ca7bd77e1e8c..dd3f6dd8e69d 100644
--- a/js/src/shell/moz.build
+++ b/js/src/shell/moz.build
@@ -20,6 +20,9 @@ UNIFIED_SOURCES += [
 DEFINES['EXPORT_JS_API'] = True
 DEFINES['ENABLE_WASM_GLOBAL'] = True
 
+if CONFIG['NIGHTLY_BUILD']:
+    DEFINES['ENABLE_WASM_GC'] = True
+
 # Also set in ../moz.build
 DEFINES['ENABLE_SHARED_ARRAY_BUFFER'] = True
 
diff --git a/js/src/threading/ProtectedData.h b/js/src/threading/ProtectedData.h
index 816bedb9ef17..9b8910613097 100644
--- a/js/src/threading/ProtectedData.h
+++ b/js/src/threading/ProtectedData.h
@@ -116,6 +116,10 @@ class ProtectedData
     T& refNoCheck() { return value; }
     const T& refNoCheck() const { return value; }
 
+    static size_t offsetOfValue() {
+        return offsetof(ThisType, value);
+    }
+
   private:
     T value;
 #ifdef JS_HAS_PROTECTED_DATA_CHECKS
diff --git a/js/src/vm/JSFunction.h b/js/src/vm/JSFunction.h
index 87b2b7a65623..104280c2ec70 100644
--- a/js/src/vm/JSFunction.h
+++ b/js/src/vm/JSFunction.h
@@ -95,6 +95,7 @@ class JSFunction : public js::NativeObject
         NATIVE_CLASS_CTOR = NATIVE_FUN | CONSTRUCTOR | CLASSCONSTRUCTOR_KIND,
         ASMJS_CTOR = ASMJS_KIND | NATIVE_CTOR,
         ASMJS_LAMBDA_CTOR = ASMJS_KIND | NATIVE_CTOR | LAMBDA,
+        ASMJS_NATIVE = ASMJS_KIND | NATIVE_FUN,
         WASM_FUN = NATIVE_FUN | WASM_OPTIMIZED,
         INTERPRETED_METHOD = INTERPRETED | METHOD_KIND,
         INTERPRETED_METHOD_GENERATOR_OR_ASYNC = INTERPRETED | METHOD_KIND,
diff --git a/js/src/wasm/AsmJS.cpp b/js/src/wasm/AsmJS.cpp
index 1b6159e4611d..0af6d48a72c9 100644
--- a/js/src/wasm/AsmJS.cpp
+++ b/js/src/wasm/AsmJS.cpp
@@ -1759,7 +1759,7 @@ class MOZ_STACK_CLASS ModuleValidator
         arrayViews_(cx),
         atomicsPresent_(false),
         simdPresent_(false),
-        env_(CompileMode::Once, Tier::Ion, DebugEnabled::False,
+        env_(CompileMode::Once, Tier::Ion, DebugEnabled::False, HasGcTypes::False,
              cx->compartment()->creationOptions().getSharedMemoryAndAtomicsEnabled()
                ? Shareable::True
                : Shareable::False,
@@ -7724,6 +7724,9 @@ ValidateGlobalVariable(JSContext* cx, const AsmJSGlobal& global, HandleValue imp
             *val = Val(simdConstant.asInt32x4());
             return true;
           }
+          case ValType::AnyRef: {
+            MOZ_CRASH("not available in asm.js");
+          }
         }
       }
     }
diff --git a/js/src/wasm/WasmAST.h b/js/src/wasm/WasmAST.h
index 50c27eb60740..90aac8fc5924 100644
--- a/js/src/wasm/WasmAST.h
+++ b/js/src/wasm/WasmAST.h
@@ -209,6 +209,7 @@ enum class AstExprKind
     Load,
     Nop,
     Pop,
+    RefNull,
     Return,
     SetGlobal,
     SetLocal,
@@ -1163,6 +1164,19 @@ class AstExtraConversionOperator final : public AstExpr
 };
 #endif
 
+class AstRefNull final : public AstExpr
+{
+    ValType refType_;
+  public:
+    static const AstExprKind Kind = AstExprKind::RefNull;
+    explicit AstRefNull(ValType refType)
+      : AstExpr(Kind, ExprType::Limit), refType_(refType)
+    {}
+    ValType refType() const {
+        return refType_;
+    }
+};
+
 // This is an artificial AST node which can fill operand slots in an AST
 // constructed from parsing or decoding stack-machine code that doesn't have
 // an inherent AST structure.
diff --git a/js/src/wasm/WasmBaselineCompile.cpp b/js/src/wasm/WasmBaselineCompile.cpp
index e8514ed861a7..9fb5a6c1301f 100644
--- a/js/src/wasm/WasmBaselineCompile.cpp
+++ b/js/src/wasm/WasmBaselineCompile.cpp
@@ -296,6 +296,15 @@ struct RegI64 : public Register64
     static RegI64 Invalid() { return RegI64(Register64::Invalid()); }
 };
 
+struct RegPtr : public Register
+{
+    RegPtr() : Register(Register::Invalid()) {}
+    explicit RegPtr(Register reg) : Register(reg) {}
+    bool isValid() const { return *this != Invalid(); }
+    bool isInvalid() const { return !isValid(); }
+    static RegPtr Invalid() { return RegPtr(Register::Invalid()); }
+};
+
 struct RegF32 : public FloatRegister
 {
     RegF32() : FloatRegister() {}
@@ -316,10 +325,21 @@ struct RegF64 : public FloatRegister
 
 struct AnyReg
 {
+    union {
+        RegI32 i32_;
+        RegI64 i64_;
+        RegPtr ref_;
+        RegF32 f32_;
+        RegF64 f64_;
+    };
+
+    enum { I32, I64, REF, F32, F64 } tag;
+
     explicit AnyReg(RegI32 r) { tag = I32; i32_ = r; }
     explicit AnyReg(RegI64 r) { tag = I64; i64_ = r; }
     explicit AnyReg(RegF32 r) { tag = F32; f32_ = r; }
     explicit AnyReg(RegF64 r) { tag = F64; f64_ = r; }
+    explicit AnyReg(RegPtr r) { tag = REF; ref_ = r; }
 
     RegI32 i32() const {
         MOZ_ASSERT(tag == I32);
@@ -337,6 +357,11 @@ struct AnyReg
         MOZ_ASSERT(tag == F64);
         return f64_;
     }
+    RegPtr ref() const {
+        MOZ_ASSERT(tag == REF);
+        return ref_;
+    }
+
     AnyRegister any() const {
         switch (tag) {
           case F32: return AnyRegister(f32_);
@@ -352,20 +377,14 @@ struct AnyReg
             // only on 64-bit platforms.
             MOZ_CRASH("AnyReg::any() on 32-bit platform");
 #endif
+          case REF:
+            MOZ_CRASH("AnyReg::any() not implemented for ref types");
           default:
             MOZ_CRASH();
         }
         // Work around GCC 5 analysis/warning bug.
         MOZ_CRASH("AnyReg::any(): impossible case");
     }
-
-    union {
-        RegI32 i32_;
-        RegI64 i64_;
-        RegF32 f32_;
-        RegF64 f64_;
-    };
-    enum { I32, I64, F32, F64 } tag;
 };
 
 // Platform-specific registers.
@@ -691,6 +710,10 @@ class BaseRegAlloc
 #endif
     }
 
+    bool isAvailablePtr(RegPtr r) {
+        return isAvailableGPR(r);
+    }
+
     bool isAvailableF32(RegF32 r) {
         return isAvailableFPU(r);
     }
@@ -726,6 +749,18 @@ class BaseRegAlloc
         allocInt64(specific);
     }
 
+    MOZ_MUST_USE RegPtr needPtr() {
+        if (!hasGPR())
+            bc.sync();
+        return RegPtr(allocGPR());
+    }
+
+    void needPtr(RegPtr specific) {
+        if (!isAvailablePtr(specific))
+            bc.sync();
+        allocGPR(specific);
+    }
+
     MOZ_MUST_USE RegF32 needF32() {
         if (!hasFPU<MIRType::Float32>())
             bc.sync();
@@ -758,6 +793,10 @@ class BaseRegAlloc
         freeInt64(r);
     }
 
+    void freePtr(RegPtr r) {
+        freeGPR(r);
+    }
+
     void freeF64(RegF64 r) {
         freeFPU(r);
     }
@@ -817,6 +856,10 @@ class BaseRegAlloc
         void addKnownF64(RegF64 r) {
             knownFPU_.add(r);
         }
+
+        void addKnownRef(RegPtr r) {
+            knownGPR_.add(r);
+        }
     };
 #endif
 };
@@ -888,23 +931,28 @@ class ScratchF32 : public ScratchFloat32Scope
 #endif
 
 #ifdef RABALDR_SCRATCH_I32
-class ScratchI32 : public BaseScratchRegister
+template<class RegType>
+class ScratchGPR : public BaseScratchRegister
 {
   public:
-    explicit ScratchI32(BaseRegAlloc& ra)
+    explicit ScratchGPR(BaseRegAlloc& ra)
       : BaseScratchRegister(ra, BaseRegAlloc::ScratchKind::I32)
     {}
-    operator RegI32() const { return RegI32(RabaldrScratchI32); }
+    operator RegType() const { return RegType(RabaldrScratchI32); }
 };
 #else
-class ScratchI32 : public ScratchRegisterScope
+template<class RegType>
+class ScratchGPR : public ScratchRegisterScope
 {
   public:
-    explicit ScratchI32(MacroAssembler& m) : ScratchRegisterScope(m) {}
-    operator RegI32() const { return RegI32(Register(*this)); }
+    explicit ScratchGPR(MacroAssembler& m) : ScratchRegisterScope(m) {}
+    operator RegType() const { return RegType(Register(*this)); }
 };
 #endif
 
+using ScratchI32 = ScratchGPR<RegI32>;
+using ScratchPtr = ScratchGPR<RegPtr>;
+
 #if defined(JS_CODEGEN_X86)
 // ScratchEBX is a mnemonic device: For some atomic ops we really need EBX,
 // no other register will do.  And we would normally have to allocate that
@@ -985,6 +1033,7 @@ BaseLocalIter::settle()
           case MIRType::Int64:
           case MIRType::Double:
           case MIRType::Float32:
+          case MIRType::Pointer:
             if (argsIter_->argInRegister())
                 frameOffset_ = pushLocal(MIRTypeToSize(mirType_));
             else
@@ -1003,6 +1052,7 @@ BaseLocalIter::settle()
           case ValType::I64:
           case ValType::F32:
           case ValType::F64:
+          case ValType::AnyRef:
             mirType_ = ToMIRType(locals_[index_]);
             frameOffset_ = pushLocal(MIRTypeToSize(mirType_));
             break;
@@ -1242,7 +1292,7 @@ class BaseStackFrame
         masm.load64(Address(sp_, localOffset(src)), dest);
     }
 
-    void loadLocalPtr(const Local& src, Register dest) {
+    void loadLocalPtr(const Local& src, RegPtr dest) {
         masm.loadPtr(Address(sp_, localOffset(src)), dest);
     }
 
@@ -1551,7 +1601,7 @@ class BaseStackFrame
     // Disambiguation: this loads a "Ptr" value from the stack, it does not load
     // the "StackPtr".
 
-    void loadStackPtr(int32_t offset, Register dest) {
+    void loadStackPtr(int32_t offset, RegPtr dest) {
         masm.loadPtr(Address(sp_, stackOffset(offset)), dest);
     }
 
@@ -1862,6 +1912,7 @@ class BaseCompiler final : public BaseCompilerInterface
 
     RegI32 joinRegI32_;
     RegI64 joinRegI64_;
+    RegPtr joinRegPtr_;
     RegF32 joinRegF32_;
     RegF64 joinRegF64_;
 
@@ -1924,16 +1975,19 @@ class BaseCompiler final : public BaseCompilerInterface
 
     bool isAvailableI32(RegI32 r) { return ra.isAvailableI32(r); }
     bool isAvailableI64(RegI64 r) { return ra.isAvailableI64(r); }
+    bool isAvailableRef(RegPtr r) { return ra.isAvailablePtr(r); }
     bool isAvailableF32(RegF32 r) { return ra.isAvailableF32(r); }
     bool isAvailableF64(RegF64 r) { return ra.isAvailableF64(r); }
 
     MOZ_MUST_USE RegI32 needI32() { return ra.needI32(); }
     MOZ_MUST_USE RegI64 needI64() { return ra.needI64(); }
+    MOZ_MUST_USE RegPtr needRef() { return ra.needPtr(); }
     MOZ_MUST_USE RegF32 needF32() { return ra.needF32(); }
     MOZ_MUST_USE RegF64 needF64() { return ra.needF64(); }
 
     void needI32(RegI32 specific) { ra.needI32(specific); }
     void needI64(RegI64 specific) { ra.needI64(specific); }
+    void needRef(RegPtr specific) { ra.needPtr(specific); }
     void needF32(RegF32 specific) { ra.needF32(specific); }
     void needF64(RegF64 specific) { ra.needF64(specific); }
 
@@ -1943,6 +1997,7 @@ class BaseCompiler final : public BaseCompilerInterface
 
     void freeI32(RegI32 r) { ra.freeI32(r); }
     void freeI64(RegI64 r) { ra.freeI64(r); }
+    void freeRef(RegPtr r) { ra.freePtr(r); }
     void freeF32(RegF32 r) { ra.freeF32(r); }
     void freeF64(RegF64 r) { ra.freeF64(r); }
 
@@ -2018,6 +2073,10 @@ class BaseCompiler final : public BaseCompilerInterface
 #endif
     }
 
+    RegI32 narrowPtr(RegPtr r) {
+        return RegI32(r);
+    }
+
     RegI32 lowPart(RegI64 r) {
 #ifdef JS_PUNBOX64
         return RegI32(r.reg);
@@ -2050,6 +2109,11 @@ class BaseCompiler final : public BaseCompilerInterface
             masm.move64(src, dest);
     }
 
+    void moveRef(RegPtr src, RegPtr dest) {
+        if (src != dest)
+            masm.movePtr(src, dest);
+    }
+
     void moveF64(RegF64 src, RegF64 dest) {
         if (src != dest)
             masm.moveDouble(src, dest);
@@ -2065,6 +2129,8 @@ class BaseCompiler final : public BaseCompilerInterface
             needI32(joinRegI32_);
         else if (type == ExprType::I64)
             needI64(joinRegI64_);
+        else if (type == ExprType::AnyRef)
+            needRef(joinRegPtr_);
     }
 
     void maybeUnreserveJoinRegI(ExprType type) {
@@ -2072,6 +2138,8 @@ class BaseCompiler final : public BaseCompilerInterface
             freeI32(joinRegI32_);
         else if (type == ExprType::I64)
             freeI64(joinRegI64_);
+        else if (type == ExprType::AnyRef)
+            freeRef(joinRegPtr_);
     }
 
     void maybeReserveJoinReg(ExprType type) {
@@ -2088,6 +2156,9 @@ class BaseCompiler final : public BaseCompilerInterface
           case ExprType::F64:
             needF64(joinRegF64_);
             break;
+          case ExprType::AnyRef:
+            needRef(joinRegPtr_);
+            break;
           default:
             break;
         }
@@ -2107,6 +2178,9 @@ class BaseCompiler final : public BaseCompilerInterface
           case ExprType::F64:
             freeF64(joinRegF64_);
             break;
+          case ExprType::AnyRef:
+            freeRef(joinRegPtr_);
+            break;
           default:
             break;
         }
@@ -2127,6 +2201,10 @@ class BaseCompiler final : public BaseCompilerInterface
 
     struct Stk
     {
+      private:
+        Stk() : kind_(Unknown), i64val_(0) {}
+
+      public:
         enum Kind
         {
             // The Mem opcodes are all clustered at the beginning to
@@ -2135,6 +2213,7 @@ class BaseCompiler final : public BaseCompilerInterface
             MemI64,               // 64-bit integer stack value ("offs")
             MemF32,               // 32-bit floating stack value ("offs")
             MemF64,               // 64-bit floating stack value ("offs")
+            MemRef,               // reftype (pointer wide) stack value ("offs")
 
             // The Local opcodes follow the Mem opcodes for a similar
             // quick test within hasLocal().
@@ -2142,47 +2221,61 @@ class BaseCompiler final : public BaseCompilerInterface
             LocalI64,             // Local int64 var ("slot")
             LocalF32,             // Local float32 var ("slot")
             LocalF64,             // Local double var ("slot")
+            LocalRef,             // Local reftype (pointer wide) var ("slot")
 
             RegisterI32,          // 32-bit integer register ("i32reg")
             RegisterI64,          // 64-bit integer register ("i64reg")
             RegisterF32,          // 32-bit floating register ("f32reg")
             RegisterF64,          // 64-bit floating register ("f64reg")
+            RegisterRef,          // reftype (pointer wide) register ("refReg")
 
             ConstI32,             // 32-bit integer constant ("i32val")
             ConstI64,             // 64-bit integer constant ("i64val")
             ConstF32,             // 32-bit floating constant ("f32val")
             ConstF64,             // 64-bit floating constant ("f64val")
+            ConstRef,             // reftype (pointer wide) constant ("refval")
+
+            Unknown,
         };
 
         Kind kind_;
 
-        static const Kind MemLast = MemF64;
-        static const Kind LocalLast = LocalF64;
+        static const Kind MemLast = MemRef;
+        static const Kind LocalLast = LocalRef;
 
         union {
             RegI32   i32reg_;
             RegI64   i64reg_;
+            RegPtr   refReg_;
             RegF32   f32reg_;
             RegF64   f64reg_;
             int32_t  i32val_;
             int64_t  i64val_;
+            intptr_t refval_;
             float    f32val_;
             double   f64val_;
             uint32_t slot_;
             uint32_t offs_;
         };
 
-        explicit Stk(RegI32 r)  : kind_(RegisterI32), i32reg_(r) {}
-        explicit Stk(RegI64 r)  : kind_(RegisterI64), i64reg_(r) {}
-        explicit Stk(RegF32 r)  : kind_(RegisterF32), f32reg_(r) {}
-        explicit Stk(RegF64 r)  : kind_(RegisterF64), f64reg_(r) {}
-        explicit Stk(int32_t v) : kind_(ConstI32), i32val_(v) {}
-        explicit Stk(int64_t v) : kind_(ConstI64), i64val_(v) {}
-        explicit Stk(float v)   : kind_(ConstF32), f32val_(v) {}
-        explicit Stk(double v)  : kind_(ConstF64), f64val_(v) {}
+        explicit Stk(RegI32 r)   : kind_(RegisterI32), i32reg_(r) {}
+        explicit Stk(RegI64 r)   : kind_(RegisterI64), i64reg_(r) {}
+        explicit Stk(RegPtr r)   : kind_(RegisterRef), refReg_(r) {}
+        explicit Stk(RegF32 r)   : kind_(RegisterF32), f32reg_(r) {}
+        explicit Stk(RegF64 r)   : kind_(RegisterF64), f64reg_(r) {}
+        explicit Stk(int32_t v)  : kind_(ConstI32), i32val_(v) {}
+        explicit Stk(int64_t v)  : kind_(ConstI64), i64val_(v) {}
+        explicit Stk(float v)    : kind_(ConstF32), f32val_(v) {}
+        explicit Stk(double v)   : kind_(ConstF64), f64val_(v) {}
         explicit Stk(Kind k, uint32_t v) : kind_(k), slot_(v) {
             MOZ_ASSERT(k > MemLast && k <= LocalLast);
         }
+        static Stk StkRef(intptr_t v) {
+            Stk s;
+            s.kind_ = ConstRef;
+            s.refval_ = v;
+            return s;
+        }
 
         void setOffs(Kind k, uint32_t v) { MOZ_ASSERT(k <= MemLast); kind_ = k; offs_ = v; }
 
@@ -2191,11 +2284,13 @@ class BaseCompiler final : public BaseCompilerInterface
 
         RegI32   i32reg() const { MOZ_ASSERT(kind_ == RegisterI32); return i32reg_; }
         RegI64   i64reg() const { MOZ_ASSERT(kind_ == RegisterI64); return i64reg_; }
+        RegPtr   refReg() const { MOZ_ASSERT(kind_ == RegisterRef); return refReg_; }
         RegF32   f32reg() const { MOZ_ASSERT(kind_ == RegisterF32); return f32reg_; }
         RegF64   f64reg() const { MOZ_ASSERT(kind_ == RegisterF64); return f64reg_; }
 
         int32_t  i32val() const { MOZ_ASSERT(kind_ == ConstI32); return i32val_; }
         int64_t  i64val() const { MOZ_ASSERT(kind_ == ConstI64); return i64val_; }
+        intptr_t refval() const { MOZ_ASSERT(kind_ == ConstRef); return refval_; }
 
         // For these two, use an out-param instead of simply returning, to
         // use the normal stack and not the x87 FP stack (which has effect on
@@ -2215,6 +2310,10 @@ class BaseCompiler final : public BaseCompilerInterface
         stk_.infallibleEmplaceBack(Stk(Forward<Args>(args)...));
     }
 
+    void pushConstRef(intptr_t v) {
+        stk_.infallibleEmplaceBack(Stk::StkRef(v));
+    }
+
     void loadConstI32(const Stk& src, RegI32 dest) {
         moveImm32(src.i32val(), dest);
     }
@@ -2247,6 +2346,22 @@ class BaseCompiler final : public BaseCompilerInterface
         moveI64(src.i64reg(), dest);
     }
 
+    void loadConstRef(const Stk& src, RegPtr dest) {
+        moveImmRef(src.refval(), dest);
+    }
+
+    void loadMemRef(const Stk& src, RegPtr dest) {
+        fr.loadStackPtr(src.offs(), dest);
+    }
+
+    void loadLocalRef(const Stk& src, RegPtr dest) {
+        fr.loadLocalPtr(localFromSlot(src.slot(), MIRType::Pointer), dest);
+    }
+
+    void loadRegisterRef(const Stk& src, RegPtr dest) {
+        moveRef(src.refReg(), dest);
+    }
+
     void loadConstF64(const Stk& src, RegF64 dest) {
         double d;
         src.f64val(&d);
@@ -2399,6 +2514,25 @@ class BaseCompiler final : public BaseCompilerInterface
         }
     }
 
+    void loadRef(const Stk& src, RegPtr dest) {
+        switch (src.kind()) {
+          case Stk::ConstRef:
+            loadConstRef(src, dest);
+            break;
+          case Stk::MemRef:
+            loadMemRef(src, dest);
+            break;
+          case Stk::LocalRef:
+            loadLocalRef(src, dest);
+            break;
+          case Stk::RegisterRef:
+            loadRegisterRef(src, dest);
+            break;
+          default:
+            MOZ_CRASH("Compiler bug: expected ref on stack");
+        }
+    }
+
     // Flush all local and register value stack elements to memory.
     //
     // TODO / OPTIMIZE: As this is fairly expensive and causes worse
@@ -2501,6 +2635,19 @@ class BaseCompiler final : public BaseCompilerInterface
                 v.setOffs(Stk::MemF32, offs);
                 break;
               }
+              case Stk::LocalRef: {
+                ScratchPtr scratch(*this);
+                loadLocalRef(v, scratch);
+                uint32_t offs = fr.pushPtr(scratch);
+                v.setOffs(Stk::MemRef, offs);
+                break;
+              }
+              case Stk::RegisterRef: {
+                uint32_t offs = fr.pushPtr(v.refReg());
+                freeRef(v.refReg());
+                v.setOffs(Stk::MemRef, offs);
+                break;
+              }
               default: {
                 break;
               }
@@ -2544,6 +2691,11 @@ class BaseCompiler final : public BaseCompilerInterface
         push(r);
     }
 
+    void pushRef(RegPtr r) {
+        MOZ_ASSERT(!isAvailableRef(r));
+        push(r);
+    }
+
     void pushF64(RegF64 r) {
         MOZ_ASSERT(!isAvailableF64(r));
         push(r);
@@ -2564,6 +2716,10 @@ class BaseCompiler final : public BaseCompilerInterface
         push(v);
     }
 
+    void pushRef(intptr_t v) {
+        pushConstRef(v);
+    }
+
     void pushF64(double v) {
         push(v);
     }
@@ -2584,6 +2740,10 @@ class BaseCompiler final : public BaseCompilerInterface
         push(Stk::LocalI64, slot);
     }
 
+    void pushLocalRef(uint32_t slot) {
+        push(Stk::LocalRef, slot);
+    }
+
     void pushLocalF64(uint32_t slot) {
         push(Stk::LocalF64, slot);
     }
@@ -2698,6 +2858,54 @@ class BaseCompiler final : public BaseCompilerInterface
         return specific;
     }
 
+    // Call only from other popRef() variants.
+    // v must be the stack top.  May pop the CPU stack.
+
+    void popRef(const Stk& v, RegPtr dest) {
+        MOZ_ASSERT(&v == &stk_.back());
+        switch (v.kind()) {
+          case Stk::ConstRef:
+            loadConstRef(v, dest);
+            break;
+          case Stk::LocalRef:
+            loadLocalRef(v, dest);
+            break;
+          case Stk::MemRef:
+            fr.popPtr(dest);
+            break;
+          case Stk::RegisterRef:
+            loadRegisterRef(v, dest);
+            break;
+          default:
+            MOZ_CRASH("Compiler bug: expected ref on stack");
+        }
+    }
+
+    RegPtr popRef(RegPtr specific) {
+        Stk& v = stk_.back();
+
+        if (!(v.kind() == Stk::RegisterRef && v.refReg() == specific)) {
+            needRef(specific);
+            popRef(v, specific);
+            if (v.kind() == Stk::RegisterRef)
+                freeRef(v.refReg());
+        }
+
+        stk_.popBack();
+        return specific;
+    }
+
+    MOZ_MUST_USE RegPtr popRef() {
+        Stk& v = stk_.back();
+        RegPtr r;
+        if (v.kind() == Stk::RegisterRef)
+            r = v.refReg();
+        else
+            popRef(v, (r = needRef()));
+        stk_.popBack();
+        return r;
+    }
+
     // Call only from other popF64() variants.
     // v must be the stack top.  May pop the CPU stack.
 
@@ -2914,6 +3122,12 @@ class BaseCompiler final : public BaseCompilerInterface
                        k == Stk::LocalF32);
             return Some(AnyReg(popF32(joinRegF32_)));
           }
+          case ExprType::AnyRef: {
+            DebugOnly<Stk::Kind> k(stk_.back().kind());
+            MOZ_ASSERT(k == Stk::RegisterRef || k == Stk::ConstRef || k == Stk::MemRef ||
+                       k == Stk::LocalRef);
+            return Some(AnyReg(popRef(joinRegPtr_)));
+          }
           default: {
             MOZ_CRASH("Compiler bug: unexpected expression type");
           }
@@ -2944,6 +3158,10 @@ class BaseCompiler final : public BaseCompilerInterface
             MOZ_ASSERT(isAvailableF64(joinRegF64_));
             needF64(joinRegF64_);
             return Some(AnyReg(joinRegF64_));
+          case ExprType::AnyRef:
+            MOZ_ASSERT(isAvailableRef(joinRegPtr_));
+            needRef(joinRegPtr_);
+            return Some(AnyReg(joinRegPtr_));
           case ExprType::Void:
             return Nothing();
           default:
@@ -2967,6 +3185,9 @@ class BaseCompiler final : public BaseCompilerInterface
           case AnyReg::F32:
             pushF32(r->f32());
             break;
+          case AnyReg::REF:
+            pushRef(r->ref());
+            break;
         }
     }
 
@@ -2986,6 +3207,9 @@ class BaseCompiler final : public BaseCompilerInterface
           case AnyReg::F32:
             freeF32(r->f32());
             break;
+          case AnyReg::REF:
+            freeRef(r->ref());
+            break;
         }
     }
 
@@ -2998,6 +3222,7 @@ class BaseCompiler final : public BaseCompilerInterface
         for (uint32_t i = stk_.length() - 1; numval > 0; numval--, i--) {
             Stk& v = stk_[i];
             switch (v.kind()) {
+              case Stk::MemRef: size += BaseStackFrame::StackSizeOfPtr;    break;
               case Stk::MemI32: size += BaseStackFrame::StackSizeOfPtr;    break;
               case Stk::MemI64: size += BaseStackFrame::StackSizeOfInt64;  break;
               case Stk::MemF64: size += BaseStackFrame::StackSizeOfDouble; break;
@@ -3024,6 +3249,9 @@ class BaseCompiler final : public BaseCompilerInterface
               case Stk::RegisterF32:
                 freeF32(v.f32reg());
                 break;
+              case Stk::RegisterRef:
+                freeRef(v.refReg());
+                break;
               default:
                 break;
             }
@@ -3070,6 +3298,9 @@ class BaseCompiler final : public BaseCompilerInterface
               case Stk::RegisterF64:
                 check.addKnownF64(item.f64reg());
                 break;
+              case Stk::RegisterRef:
+                check.addKnownRef(item.refReg());
+                break;
               default:
                 break;
             }
@@ -3159,6 +3390,9 @@ class BaseCompiler final : public BaseCompilerInterface
               case MIRType::Int64:
                 fr.storeLocalI64(RegI64(i->gpr64()), l);
                 break;
+              case MIRType::Pointer:
+                fr.storeLocalPtr(RegPtr(i->gpr()), l);
+                break;
               case MIRType::Double:
                 fr.storeLocalF64(RegF64(i->fpu()), l);
                 break;
@@ -3488,6 +3722,17 @@ class BaseCompiler final : public BaseCompilerInterface
             }
             break;
           }
+          case ValType::AnyRef: {
+            ABIArg argLoc = call->abi.next(MIRType::Pointer);
+            if (argLoc.kind() == ABIArg::Stack) {
+                ScratchPtr scratch(*this);
+                loadRef(arg, scratch);
+                masm.storePtr(scratch, Address(masm.getStackPointer(), argLoc.offsetFromArgBase()));
+            } else {
+                loadRef(arg, RegPtr(argLoc.gpr()));
+            }
+            break;
+          }
           default:
             MOZ_CRASH("Function argument type");
         }
@@ -3561,6 +3806,10 @@ class BaseCompiler final : public BaseCompilerInterface
         masm.move64(Imm64(v), dest);
     }
 
+    void moveImmRef(intptr_t v, RegPtr dest) {
+        masm.movePtr(ImmWord(v), dest);
+    }
+
     void moveImmF32(float f, RegF32 dest) {
         masm.loadConstantFloat32(f, dest);
     }
@@ -3691,6 +3940,13 @@ class BaseCompiler final : public BaseCompilerInterface
         return r;
     }
 
+    RegPtr captureReturnedRef() {
+        RegPtr r = RegPtr(ReturnReg);
+        MOZ_ASSERT(isAvailableRef(r));
+        needRef(r);
+        return r;
+    }
+
     void returnCleanup(bool popStack) {
         if (popStack)
             fr.popStackBeforeBranch(controlOutermost().stackHeight);
@@ -5275,6 +5531,11 @@ class BaseCompiler final : public BaseCompilerInterface
         *r0 = popF64();
     }
 
+    void pop2xRef(RegPtr* r0, RegPtr* r1) {
+        *r1 = popRef();
+        *r0 = popRef();
+    }
+
     RegI32 popI64ToI32() {
         RegI64 r = popI64();
         return narrowI64(r);
@@ -5614,6 +5875,9 @@ class BaseCompiler final : public BaseCompilerInterface
     MOZ_MUST_USE bool emitGrowMemory();
     MOZ_MUST_USE bool emitCurrentMemory();
 
+    MOZ_MUST_USE bool emitRefNull();
+    void emitRefIsNull();
+
     MOZ_MUST_USE bool emitAtomicCmpXchg(ValType type, Scalar::Type viewType);
     MOZ_MUST_USE bool emitAtomicLoad(ValType type, Scalar::Type viewType);
     MOZ_MUST_USE bool emitAtomicRMW(ValType type, Scalar::Type viewType, AtomicOp op);
@@ -6851,10 +7115,9 @@ BaseCompiler::sniffConditionalControlCmp(Cond compareOp, ValType operandType)
     OpBytes op;
     iter_.peekOp(&op);
     switch (op.b0) {
-      case uint16_t(Op::Select):
-        MOZ_FALLTHROUGH;
       case uint16_t(Op::BrIf):
       case uint16_t(Op::If):
+      case uint16_t(Op::Select):
         setLatentCompare(compareOp, operandType);
         return true;
       default:
@@ -7436,6 +7699,12 @@ BaseCompiler::doReturn(ExprType type, bool popStack)
         freeF32(rv);
         break;
       }
+      case ExprType::AnyRef: {
+        RegPtr rv = popRef(RegPtr(ReturnReg));
+        returnCleanup(popStack);
+        freeRef(rv);
+        break;
+      }
       default: {
         MOZ_CRASH("Function return type");
       }
@@ -7500,6 +7769,11 @@ BaseCompiler::pushReturned(const FunctionCall& call, ExprType type)
         pushF64(rv);
         break;
       }
+      case ExprType::AnyRef: {
+        RegPtr rv = captureReturnedRef();
+        pushRef(rv);
+        break;
+      }
       default:
         MOZ_CRASH("Function return type");
     }
@@ -7827,6 +8101,9 @@ BaseCompiler::emitGetLocal()
       case ValType::F32:
         pushLocalF32(slot);
         break;
+      case ValType::AnyRef:
+        pushLocalRef(slot);
+        break;
       default:
         MOZ_CRASH("Local variable type");
     }
@@ -7883,6 +8160,16 @@ BaseCompiler::emitSetOrTeeLocal(uint32_t slot)
             pushF32(rv);
         break;
       }
+      case ValType::AnyRef: {
+        RegPtr rv = popRef();
+        syncLocal(slot);
+        fr.storeLocalPtr(rv, localFromSlot(slot, MIRType::Pointer));
+        if (isSetLocal)
+            freeRef(rv);
+        else
+            pushRef(rv);
+        break;
+      }
       default:
         MOZ_CRASH("Local variable type");
     }
@@ -8403,6 +8690,16 @@ BaseCompiler::emitSelect()
         pushF64(r);
         break;
       }
+      case ValType::AnyRef: {
+        RegPtr r, rs;
+        pop2xRef(&r, &rs);
+        emitBranchPerform(&b);
+        moveRef(rs, r);
+        masm.bind(&done);
+        freeRef(rs);
+        pushRef(r);
+        break;
+      }
       default: {
         MOZ_CRASH("select type");
       }
@@ -8557,6 +8854,29 @@ BaseCompiler::emitCurrentMemory()
     return true;
 }
 
+bool
+BaseCompiler::emitRefNull()
+{
+    if (!iter_.readRefNull())
+        return false;
+
+    if (deadCode_)
+        return true;
+
+    pushRef(NULLREF_VALUE);
+    return true;
+}
+
+void
+BaseCompiler::emitRefIsNull()
+{
+    RegPtr r = popRef();
+    RegI32 rd = narrowPtr(r);
+
+    masm.cmpPtrSet(Assembler::Equal, r, ImmWord(NULLREF_VALUE), rd);
+    pushI32(rd);
+}
+
 bool
 BaseCompiler::emitAtomicCmpXchg(ValType type, Scalar::Type viewType)
 {
@@ -9424,6 +9744,19 @@ BaseCompiler::emitBody()
           case uint16_t(Op::CurrentMemory):
             CHECK_NEXT(emitCurrentMemory());
 
+#ifdef ENABLE_WASM_GC
+          case uint16_t(Op::RefNull):
+            if (env_.gcTypesEnabled == HasGcTypes::False)
+                return iter_.unrecognizedOpcode(&op);
+            CHECK_NEXT(emitRefNull());
+            break;
+          case uint16_t(Op::RefIsNull):
+            if (env_.gcTypesEnabled == HasGcTypes::False)
+                return iter_.unrecognizedOpcode(&op);
+            CHECK_NEXT(emitConversion(emitRefIsNull, ValType::AnyRef, ValType::I32));
+            break;
+#endif
+
           // Numeric operations
           case uint16_t(Op::NumericPrefix): {
 #ifdef ENABLE_WASM_SATURATING_TRUNC_OPS
@@ -9702,6 +10035,7 @@ BaseCompiler::BaseCompiler(const ModuleEnvironment& env,
       fr(*masm),
       joinRegI32_(RegI32(ReturnReg)),
       joinRegI64_(RegI64(ReturnReg64)),
+      joinRegPtr_(RegPtr(ReturnReg)),
       joinRegF32_(RegF32(ReturnFloat32Reg)),
       joinRegF64_(RegF64(ReturnDoubleReg))
 {
@@ -9809,7 +10143,7 @@ js::wasm::BaselineCompileFunctions(const ModuleEnvironment& env, LifoAlloc& lifo
         ValTypeVector locals;
         if (!locals.appendAll(env.funcSigs[func.index]->args()))
             return false;
-        if (!DecodeLocalEntries(d, env.kind, &locals))
+        if (!DecodeLocalEntries(d, env.kind, env.gcTypesEnabled, &locals))
             return false;
 
         // One-pass baseline compilation.
diff --git a/js/src/wasm/WasmBinaryConstants.h b/js/src/wasm/WasmBinaryConstants.h
index 76147c12f457..2b5b08169e4a 100644
--- a/js/src/wasm/WasmBinaryConstants.h
+++ b/js/src/wasm/WasmBinaryConstants.h
@@ -62,6 +62,9 @@ enum class TypeCode
     // A function pointer with any signature
     AnyFunc                              = 0x70,  // SLEB128(-0x10)
 
+    // A reference to any type.
+    AnyRef                               = 0x6f,
+
     // Type constructor for function types
     Func                                 = 0x60,  // SLEB128(-0x20)
 
@@ -78,6 +81,8 @@ enum class ValType
     F32                                  = uint8_t(TypeCode::F32),
     F64                                  = uint8_t(TypeCode::F64),
 
+    AnyRef                               = uint8_t(TypeCode::AnyRef),
+
     // ------------------------------------------------------------------------
     // The rest of these types are currently only emitted internally when
     // compiling asm.js and are rejected by wasm validation.
@@ -93,6 +98,10 @@ enum class ValType
 
 typedef Vector<ValType, 8, SystemAllocPolicy> ValTypeVector;
 
+// The representation of a null reference value throughout the compiler.
+
+static const intptr_t NULLREF_VALUE = intptr_t((void*)nullptr);
+
 enum class DefinitionKind
 {
     Function                             = 0x00,
@@ -323,6 +332,10 @@ enum class Op
     I64Extend32S                         = 0xc4,
 #endif
 
+    // GC ops
+    RefNull                              = 0xd0,
+    RefIsNull                            = 0xd1,
+
     FirstPrefix                          = 0xfc,
     NumericPrefix                        = 0xfc,
     ThreadPrefix                         = 0xfe,
diff --git a/js/src/wasm/WasmBinaryIterator.cpp b/js/src/wasm/WasmBinaryIterator.cpp
index 6e4764547855..7ada51160995 100644
--- a/js/src/wasm/WasmBinaryIterator.cpp
+++ b/js/src/wasm/WasmBinaryIterator.cpp
@@ -177,6 +177,7 @@ wasm::Classify(OpBytes op)
       case Op::F64ConvertUI64:
       case Op::F64ReinterpretI64:
       case Op::F64PromoteF32:
+      case Op::RefIsNull:
 #ifdef ENABLE_WASM_SIGNEXTEND_OPS
       case Op::I32Extend8S:
       case Op::I32Extend16S:
@@ -240,6 +241,8 @@ wasm::Classify(OpBytes op)
         return OpKind::CurrentMemory;
       case Op::GrowMemory:
         return OpKind::GrowMemory;
+      case Op::RefNull:
+        return OpKind::RefNull;
       case Op::NumericPrefix: {
 #ifdef ENABLE_WASM_SATURATING_TRUNC_OPS
           switch (NumericOp(op.b1)) {
diff --git a/js/src/wasm/WasmBinaryIterator.h b/js/src/wasm/WasmBinaryIterator.h
index a06b6bde7d32..c6b4e0398e97 100644
--- a/js/src/wasm/WasmBinaryIterator.h
+++ b/js/src/wasm/WasmBinaryIterator.h
@@ -41,20 +41,22 @@ enum class LabelKind : uint8_t
 // represents the type of a value produced by an unconditional branch.
 enum class StackType
 {
-    I32   = uint8_t(ValType::I32),
-    I64   = uint8_t(ValType::I64),
-    F32   = uint8_t(ValType::F32),
-    F64   = uint8_t(ValType::F64),
+    I32    = uint8_t(ValType::I32),
+    I64    = uint8_t(ValType::I64),
+    F32    = uint8_t(ValType::F32),
+    F64    = uint8_t(ValType::F64),
 
-    I8x16 = uint8_t(ValType::I8x16),
-    I16x8 = uint8_t(ValType::I16x8),
-    I32x4 = uint8_t(ValType::I32x4),
-    F32x4 = uint8_t(ValType::F32x4),
-    B8x16 = uint8_t(ValType::B8x16),
-    B16x8 = uint8_t(ValType::B16x8),
-    B32x4 = uint8_t(ValType::B32x4),
+    I8x16  = uint8_t(ValType::I8x16),
+    I16x8  = uint8_t(ValType::I16x8),
+    I32x4  = uint8_t(ValType::I32x4),
+    F32x4  = uint8_t(ValType::F32x4),
+    B8x16  = uint8_t(ValType::B8x16),
+    B16x8  = uint8_t(ValType::B16x8),
+    B32x4  = uint8_t(ValType::B32x4),
 
-    Any   = uint8_t(TypeCode::Limit)
+    AnyRef = uint8_t(ValType::AnyRef),
+
+    Any    = uint8_t(TypeCode::Limit),
 };
 
 static inline StackType
@@ -71,7 +73,49 @@ NonAnyToValType(StackType type)
 }
 
 static inline bool
-Unify(StackType one, StackType two, StackType* result)
+IsRefType(StackType st)
+{
+    return IsRefType(NonAnyToValType(st));
+}
+
+static inline bool
+IsSubtypeOf(StackType one, StackType two)
+{
+    MOZ_ASSERT(IsRefType(one));
+    MOZ_ASSERT(IsRefType(two));
+    return one == two || two == StackType::AnyRef;
+}
+
+static inline bool
+Unify(HasGcTypes gcTypesEnabled, StackType observed, StackType expected, StackType* result)
+{
+    if (MOZ_LIKELY(observed == expected)) {
+        *result = observed;
+        return true;
+    }
+
+    if (observed == StackType::Any) {
+        *result = expected;
+        return true;
+    }
+
+    if (expected == StackType::Any) {
+        *result = observed;
+        return true;
+    }
+
+    if (gcTypesEnabled == HasGcTypes::True && IsRefType(observed) && IsRefType(expected) &&
+        IsSubtypeOf(observed, expected))
+    {
+        *result = expected;
+        return true;
+    }
+
+    return false;
+}
+
+static inline bool
+Join(HasGcTypes gcTypesEnabled, StackType one, StackType two, StackType* result)
 {
     if (MOZ_LIKELY(one == two)) {
         *result = one;
@@ -88,6 +132,22 @@ Unify(StackType one, StackType two, StackType* result)
         return true;
     }
 
+    if (gcTypesEnabled == HasGcTypes::True && IsRefType(one) && IsRefType(two)) {
+        if (IsSubtypeOf(two, one)) {
+            *result = one;
+            return true;
+        }
+
+        if (IsSubtypeOf(one, two)) {
+            *result = two;
+            return true;
+        }
+
+        // No subtyping relations between the two types.
+        *result = StackType::AnyRef;
+        return true;
+    }
+
     return false;
 }
 
@@ -113,7 +173,6 @@ enum class OpKind {
     BrIf,
     BrTable,
     Nop,
-    Nullary,
     Unary,
     Binary,
     Comparison,
@@ -159,6 +218,7 @@ enum class OpKind {
     SimdBooleanReduction,
     SimdShiftByScalar,
     SimdComparison,
+    RefNull,
 };
 
 // Return the OpKind for a given Op. This is used for sanity-checking that
@@ -534,6 +594,7 @@ class MOZ_STACK_CLASS OpIter : private Policy
     MOZ_MUST_USE bool readB8x16Const(I8x16* i8x16);
     MOZ_MUST_USE bool readB16x8Const(I16x8* i16x8);
     MOZ_MUST_USE bool readB32x4Const(I32x4* i32x4);
+    MOZ_MUST_USE bool readRefNull();
     MOZ_MUST_USE bool readCall(uint32_t* calleeIndex, ValueVector* argValues);
     MOZ_MUST_USE bool readCallIndirect(uint32_t* sigIndex, Value* callee, ValueVector* argValues);
     MOZ_MUST_USE bool readOldCallDirect(uint32_t numFuncImports, uint32_t* funcIndex,
@@ -731,7 +792,7 @@ OpIter<Policy>::popWithType(StackType expectedType, Value* value)
     TypeAndValue<Value> tv = valueStack_.popCopy();
 
     StackType _;
-    if (MOZ_UNLIKELY(!Unify(tv.type(), expectedType, &_)))
+    if (MOZ_UNLIKELY(!Unify(env_.gcTypesEnabled, tv.type(), expectedType, &_)))
         return typeMismatch(tv.type(), expectedType);
 
     *value = tv.value();
@@ -783,8 +844,11 @@ OpIter<Policy>::topWithType(ValType expectedType, Value* value)
 
     TypeAndValue<Value>& tv = valueStack_.back();
 
-    if (MOZ_UNLIKELY(!Unify(tv.type(), ToStackType(expectedType), &tv.typeRef())))
+    if (MOZ_UNLIKELY(!Unify(env_.gcTypesEnabled, tv.type(), ToStackType(expectedType),
+                            &tv.typeRef())))
+    {
         return typeMismatch(tv.type(), ToStackType(expectedType));
+    }
 
     *value = tv.value();
     return true;
@@ -846,6 +910,7 @@ OpIter<Policy>::readBlockType(ExprType* type)
     if (!d_.readBlockType(&unchecked))
         return fail("unable to read block signature");
 
+    bool known = false;
     switch (unchecked) {
       case uint8_t(ExprType::Void):
       case uint8_t(ExprType::I32):
@@ -859,11 +924,18 @@ OpIter<Policy>::readBlockType(ExprType* type)
       case uint8_t(ExprType::B8x16):
       case uint8_t(ExprType::B16x8):
       case uint8_t(ExprType::B32x4):
+        known = true;
+        break;
+      case uint8_t(ExprType::AnyRef):
+        known = env_.gcTypesEnabled == HasGcTypes::True;
+        break;
+      case uint8_t(ExprType::Limit):
         break;
-      default:
-        return fail("invalid inline block type");
     }
 
+    if (!known)
+        return fail("invalid inline block type");
+
     *type = ExprType(unchecked);
     return true;
 }
@@ -1382,7 +1454,7 @@ OpIter<Policy>::readSelect(StackType* type, Value* trueValue, Value* falseValue,
     if (!popAnyType(&trueType, trueValue))
         return false;
 
-    if (!Unify(falseType, trueType, type))
+    if (!Join(env_.gcTypesEnabled, falseType, trueType, type))
         return fail("select operand types must match");
 
     infalliblePush(*type);
@@ -1595,6 +1667,17 @@ OpIter<Policy>::readB32x4Const(I32x4* i32x4)
            push(ValType::B32x4);
 }
 
+template <typename Policy>
+inline bool
+OpIter<Policy>::readRefNull()
+{
+    MOZ_ASSERT(Classify(op_) == OpKind::RefNull);
+    uint8_t valType;
+    if (!d_.readValType(&valType) || ValType(valType) != ValType::AnyRef)
+        return fail("unknown nullref type");
+    return push(StackType::AnyRef);
+}
+
 template <typename Policy>
 inline bool
 OpIter<Policy>::popCallArgs(const ValTypeVector& expectedTypes, ValueVector* values)
diff --git a/js/src/wasm/WasmBinaryToAST.cpp b/js/src/wasm/WasmBinaryToAST.cpp
index ea3b46e2646f..55622e9e6b67 100644
--- a/js/src/wasm/WasmBinaryToAST.cpp
+++ b/js/src/wasm/WasmBinaryToAST.cpp
@@ -102,7 +102,7 @@ class AstDecodeContext
        lifo(lifo),
        d(d),
        generateNames(generateNames),
-       env_(CompileMode::Once, Tier::Ion, DebugEnabled::False,
+       env_(CompileMode::Once, Tier::Ion, DebugEnabled::False, HasGcTypes::False,
             cx->compartment()->creationOptions().getSharedMemoryAndAtomicsEnabled()
             ? Shareable::True
             : Shareable::False),
@@ -1824,7 +1824,7 @@ AstDecodeFunctionBody(AstDecodeContext &c, uint32_t funcIndex, AstFunc** func)
     if (!locals.appendAll(sig->args()))
         return false;
 
-    if (!DecodeLocalEntries(c.d, ModuleKind::Wasm, &locals))
+    if (!DecodeLocalEntries(c.d, ModuleKind::Wasm, c.env().gcTypesEnabled, &locals))
         return false;
 
     AstDecodeOpIter iter(c.env(), c.d);
diff --git a/js/src/wasm/WasmBuiltins.cpp b/js/src/wasm/WasmBuiltins.cpp
index 846830d311d6..3ae6c83e5d5b 100644
--- a/js/src/wasm/WasmBuiltins.cpp
+++ b/js/src/wasm/WasmBuiltins.cpp
@@ -536,6 +536,9 @@ AddressOf(SymbolicAddress imm, ABIFunctionType* abiType)
       case SymbolicAddress::CallImport_F64:
         *abiType = Args_General4;
         return FuncCast(Instance::callImport_f64, *abiType);
+      case SymbolicAddress::CallImport_Ref:
+        *abiType = Args_General4;
+        return FuncCast(Instance::callImport_ref, *abiType);
       case SymbolicAddress::CoerceInPlace_ToInt32:
         *abiType = Args_General1;
         return FuncCast(CoerceInPlace_ToInt32, *abiType);
@@ -690,6 +693,7 @@ wasm::NeedsBuiltinThunk(SymbolicAddress sym)
       case SymbolicAddress::CallImport_I32:
       case SymbolicAddress::CallImport_I64:
       case SymbolicAddress::CallImport_F64:
+      case SymbolicAddress::CallImport_Ref:
       case SymbolicAddress::CoerceInPlace_ToInt32:    // GenerateImportJitExit
       case SymbolicAddress::CoerceInPlace_ToNumber:
 #if defined(JS_CODEGEN_MIPS32)
diff --git a/js/src/wasm/WasmCode.cpp b/js/src/wasm/WasmCode.cpp
index 88564c7e1f66..b1dd00a3cda0 100644
--- a/js/src/wasm/WasmCode.cpp
+++ b/js/src/wasm/WasmCode.cpp
@@ -609,22 +609,25 @@ LazyStubSegment::addStubs(size_t codeLength, const Uint32Vector& funcExportIndic
         return false;
 
     size_t i = 0;
-    for (DebugOnly<uint32_t> funcExportIndex : funcExportIndices) {
+    for (uint32_t funcExportIndex : funcExportIndices) {
         const CodeRange& interpRange = codeRanges[i];
         MOZ_ASSERT(interpRange.isInterpEntry());
         MOZ_ASSERT(interpRange.funcIndex() == funcExports[funcExportIndex].funcIndex());
 
         codeRanges_.infallibleAppend(interpRange);
         codeRanges_.back().offsetBy(offsetInSegment);
+        i++;
 
-        const CodeRange& jitRange = codeRanges[i + 1];
+        if (funcExports[funcExportIndex].sig().temporarilyUnsupportedAnyRef())
+            continue;
+
+        const CodeRange& jitRange = codeRanges[i];
         MOZ_ASSERT(jitRange.isJitEntry());
         MOZ_ASSERT(jitRange.funcIndex() == interpRange.funcIndex());
 
         codeRanges_.infallibleAppend(jitRange);
         codeRanges_.back().offsetBy(offsetInSegment);
-
-        i += 2;
+        i++;
     }
 
     return true;
@@ -658,8 +661,8 @@ struct ProjectLazyFuncIndex
 static constexpr unsigned LAZY_STUB_LIFO_DEFAULT_CHUNK_SIZE = 8 * 1024;
 
 bool
-LazyStubTier::createMany(const Uint32Vector& funcExportIndices, const CodeTier& codeTier,
-                         size_t* stubSegmentIndex)
+LazyStubTier::createMany(HasGcTypes gcTypesEnabled, const Uint32Vector& funcExportIndices,
+                         const CodeTier& codeTier, size_t* stubSegmentIndex)
 {
     MOZ_ASSERT(funcExportIndices.length());
 
@@ -673,16 +676,21 @@ LazyStubTier::createMany(const Uint32Vector& funcExportIndices, const CodeTier&
     uint8_t* moduleSegmentBase = codeTier.segment().base();
 
     CodeRangeVector codeRanges;
+    DebugOnly<uint32_t> numExpectedRanges = 0;
     for (uint32_t funcExportIndex : funcExportIndices) {
         const FuncExport& fe = funcExports[funcExportIndex];
+        numExpectedRanges += fe.sig().temporarilyUnsupportedAnyRef() ? 1 : 2;
         void* calleePtr = moduleSegmentBase +
                           moduleRanges[fe.interpCodeRangeIndex()].funcNormalEntry();
         Maybe<ImmPtr> callee;
         callee.emplace(calleePtr, ImmPtr::NoCheckToken());
-        if (!GenerateEntryStubs(masm, funcExportIndex, fe, callee, /* asmjs*/ false, &codeRanges))
+        if (!GenerateEntryStubs(masm, funcExportIndex, fe, callee, /* asmjs */ false,
+                                gcTypesEnabled, &codeRanges))
+        {
             return false;
+        }
     }
-    MOZ_ASSERT(codeRanges.length() == 2 * funcExportIndices.length(), "two entries per function");
+    MOZ_ASSERT(codeRanges.length() == numExpectedRanges, "incorrect number of entries per function");
 
     masm.finish();
 
@@ -743,7 +751,9 @@ LazyStubTier::createMany(const Uint32Vector& funcExportIndices, const CodeTier&
                                       fe.funcIndex(), &exportIndex));
         MOZ_ALWAYS_TRUE(exports_.insert(exports_.begin() + exportIndex, Move(lazyExport)));
 
-        interpRangeIndex += 2;
+        // Functions with anyref in their sig have only one entry (interp).
+        // All other functions get an extra jit entry.
+        interpRangeIndex += fe.sig().temporarilyUnsupportedAnyRef() ? 1 : 2;
     }
 
     return true;
@@ -757,12 +767,22 @@ LazyStubTier::createOne(uint32_t funcExportIndex, const CodeTier& codeTier)
         return false;
 
     size_t stubSegmentIndex;
-    if (!createMany(funcExportIndexes, codeTier, &stubSegmentIndex))
+    if (!createMany(codeTier.code().metadata().temporaryHasGcTypes, funcExportIndexes, codeTier,
+                    &stubSegmentIndex))
+    {
         return false;
+    }
 
     const UniqueLazyStubSegment& segment = stubSegments_[stubSegmentIndex];
     const CodeRangeVector& codeRanges = segment->codeRanges();
 
+    // Functions that have anyref in their sig don't get a jit entry.
+    if (codeTier.metadata().funcExports[funcExportIndex].sig().temporarilyUnsupportedAnyRef()) {
+        MOZ_ASSERT(codeRanges.length() >= 1);
+        MOZ_ASSERT(codeRanges.back().isInterpEntry());
+        return true;
+    }
+
     MOZ_ASSERT(codeRanges.length() >= 2);
     MOZ_ASSERT(codeRanges[codeRanges.length() - 2].isInterpEntry());
 
@@ -774,14 +794,14 @@ LazyStubTier::createOne(uint32_t funcExportIndex, const CodeTier& codeTier)
 }
 
 bool
-LazyStubTier::createTier2(const Uint32Vector& funcExportIndices, const CodeTier& codeTier,
-                          Maybe<size_t>* outStubSegmentIndex)
+LazyStubTier::createTier2(HasGcTypes gcTypesEnabled, const Uint32Vector& funcExportIndices,
+                          const CodeTier& codeTier, Maybe<size_t>* outStubSegmentIndex)
 {
     if (!funcExportIndices.length())
         return true;
 
     size_t stubSegmentIndex;
-    if (!createMany(funcExportIndices, codeTier, &stubSegmentIndex))
+    if (!createMany(gcTypesEnabled, funcExportIndices, codeTier, &stubSegmentIndex))
         return false;
 
     outStubSegmentIndex->emplace(stubSegmentIndex);
diff --git a/js/src/wasm/WasmCode.h b/js/src/wasm/WasmCode.h
index e434887cbfb1..a1341c695cc2 100644
--- a/js/src/wasm/WasmCode.h
+++ b/js/src/wasm/WasmCode.h
@@ -400,6 +400,7 @@ struct MetadataCacheablePod
 {
     ModuleKind            kind;
     MemoryUsage           memoryUsage;
+    HasGcTypes            temporaryHasGcTypes;
     uint32_t              minMemoryLength;
     uint32_t              globalDataLength;
     Maybe<uint32_t>       maxMemoryLength;
@@ -408,6 +409,7 @@ struct MetadataCacheablePod
     explicit MetadataCacheablePod(ModuleKind kind)
       : kind(kind),
         memoryUsage(MemoryUsage::None),
+        temporaryHasGcTypes(HasGcTypes::False),
         minMemoryLength(0),
         globalDataLength(0)
     {}
@@ -572,8 +574,8 @@ class LazyStubTier
     LazyFuncExportVector exports_;
     size_t lastStubSegmentIndex_;
 
-    bool createMany(const Uint32Vector& funcExportIndices, const CodeTier& codeTier,
-                    size_t* stubSegmentIndex);
+    bool createMany(HasGcTypes gcTypesEnabled, const Uint32Vector& funcExportIndices,
+                    const CodeTier& codeTier, size_t* stubSegmentIndex);
 
   public:
     LazyStubTier() : lastStubSegmentIndex_(0) {}
@@ -593,8 +595,8 @@ class LazyStubTier
     // them in a single stub. Jit entries won't be used until
     // setJitEntries() is actually called, after the Code owner has committed
     // tier2.
-    bool createTier2(const Uint32Vector& funcExportIndices, const CodeTier& codeTier,
-                     Maybe<size_t>* stubSegmentIndex);
+    bool createTier2(HasGcTypes gcTypesEnabled, const Uint32Vector& funcExportIndices,
+                     const CodeTier& codeTier, Maybe<size_t>* stubSegmentIndex);
     void setJitEntries(const Maybe<size_t>& stubSegmentIndex, const Code& code);
 
     void addSizeOfMisc(MallocSizeOf mallocSizeOf, size_t* code, size_t* data) const;
diff --git a/js/src/wasm/WasmCompile.cpp b/js/src/wasm/WasmCompile.cpp
index ff8b59945b11..812e81ba3c5e 100644
--- a/js/src/wasm/WasmCompile.cpp
+++ b/js/src/wasm/WasmCompile.cpp
@@ -87,10 +87,17 @@ DecodeCodeSection(const ModuleEnvironment& env, DecoderT& d, ModuleGenerator& mg
 bool
 CompileArgs::initFromContext(JSContext* cx, ScriptedCaller&& scriptedCaller)
 {
-    baselineEnabled = cx->options().wasmBaseline();
-    ionEnabled = cx->options().wasmIon();
+#ifdef ENABLE_WASM_GC
+    bool gcEnabled = cx->options().wasmGc();
+#else
+    bool gcEnabled = false;
+#endif
+
+    baselineEnabled = cx->options().wasmBaseline() || gcEnabled;
+    ionEnabled = cx->options().wasmIon() && !gcEnabled;
     sharedMemoryEnabled = cx->compartment()->creationOptions().getSharedMemoryAndAtomicsEnabled();
-    testTiering = cx->options().testWasmAwaitTier2() || JitOptions.wasmDelayTier2;
+    gcTypesEnabled = gcEnabled ? HasGcTypes::True : HasGcTypes::False;
+    testTiering = (cx->options().testWasmAwaitTier2() || JitOptions.wasmDelayTier2) && !gcEnabled;
 
     // Debug information such as source view or debug traps will require
     // additional memory and permanently stay in baseline code, so we try to
@@ -424,7 +431,7 @@ wasm::CompileBuffer(const CompileArgs& args, const ShareableBytes& bytecode, Uni
     DebugEnabled debug;
     InitialCompileFlags(args, d, &mode, &tier, &debug);
 
-    ModuleEnvironment env(mode, tier, debug,
+    ModuleEnvironment env(mode, tier, debug, args.gcTypesEnabled,
                           args.sharedMemoryEnabled ? Shareable::True : Shareable::False);
     if (!DecodeModuleEnvironment(d, &env))
         return nullptr;
@@ -450,7 +457,9 @@ wasm::CompileTier2(const CompileArgs& args, Module& module, Atomic<bool>* cancel
     UniqueChars error;
     Decoder d(module.bytecode().bytes, 0, &error);
 
-    ModuleEnvironment env(CompileMode::Tier2, Tier::Ion, DebugEnabled::False,
+    MOZ_ASSERT(args.gcTypesEnabled == HasGcTypes::False, "can't ion-compile with gc types yet");
+
+    ModuleEnvironment env(CompileMode::Tier2, Tier::Ion, DebugEnabled::False, HasGcTypes::False,
                           args.sharedMemoryEnabled ? Shareable::True : Shareable::False);
     if (!DecodeModuleEnvironment(d, &env))
         return false;
@@ -572,7 +581,7 @@ wasm::CompileStreaming(const CompileArgs& args,
         DebugEnabled debug;
         InitialCompileFlags(args, d, &mode, &tier, &debug);
 
-        env.emplace(mode, tier, debug,
+        env.emplace(mode, tier, debug, args.gcTypesEnabled,
                     args.sharedMemoryEnabled ? Shareable::True : Shareable::False);
         if (!DecodeModuleEnvironment(d, env.ptr()))
             return nullptr;
diff --git a/js/src/wasm/WasmCompile.h b/js/src/wasm/WasmCompile.h
index 85e13a3726f4..7d22e746d0ff 100644
--- a/js/src/wasm/WasmCompile.h
+++ b/js/src/wasm/WasmCompile.h
@@ -50,6 +50,7 @@ struct CompileArgs : ShareableBase<CompileArgs>
     bool debugEnabled;
     bool ionEnabled;
     bool sharedMemoryEnabled;
+    HasGcTypes gcTypesEnabled;
     bool testTiering;
 
     CompileArgs(Assumptions&& assumptions, ScriptedCaller&& scriptedCaller)
@@ -59,6 +60,7 @@ struct CompileArgs : ShareableBase<CompileArgs>
         debugEnabled(false),
         ionEnabled(false),
         sharedMemoryEnabled(false),
+        gcTypesEnabled(HasGcTypes::False),
         testTiering(false)
     {}
 
diff --git a/js/src/wasm/WasmDebug.cpp b/js/src/wasm/WasmDebug.cpp
index eb57c55ffab1..e2738190337d 100644
--- a/js/src/wasm/WasmDebug.cpp
+++ b/js/src/wasm/WasmDebug.cpp
@@ -542,7 +542,7 @@ DebugState::debugGetLocalTypes(uint32_t funcIndex, ValTypeVector* locals, size_t
     size_t offsetInModule = range.funcLineOrBytecode();
     Decoder d(maybeBytecode_->begin() + offsetInModule,  maybeBytecode_->end(),
               offsetInModule, /* error = */ nullptr);
-    return DecodeLocalEntries(d, metadata().kind, locals);
+    return DecodeLocalEntries(d, metadata().kind, metadata().temporaryHasGcTypes, locals);
 }
 
 ExprType
diff --git a/js/src/wasm/WasmFrameIter.cpp b/js/src/wasm/WasmFrameIter.cpp
index 3807e10f8ea9..d1146bbb37ab 100644
--- a/js/src/wasm/WasmFrameIter.cpp
+++ b/js/src/wasm/WasmFrameIter.cpp
@@ -1139,6 +1139,7 @@ ThunkedNativeToDescription(SymbolicAddress func)
       case SymbolicAddress::CallImport_I32:
       case SymbolicAddress::CallImport_I64:
       case SymbolicAddress::CallImport_F64:
+      case SymbolicAddress::CallImport_Ref:
       case SymbolicAddress::CoerceInPlace_ToInt32:
       case SymbolicAddress::CoerceInPlace_ToNumber:
         MOZ_ASSERT(!NeedsBuiltinThunk(func), "not in sync with NeedsBuiltinThunk");
diff --git a/js/src/wasm/WasmGenerator.cpp b/js/src/wasm/WasmGenerator.cpp
index 012f9cefe716..185b76483c44 100644
--- a/js/src/wasm/WasmGenerator.cpp
+++ b/js/src/wasm/WasmGenerator.cpp
@@ -840,6 +840,7 @@ ModuleGenerator::finishMetadata(const ShareableBytes& bytecode)
     // Copy over data from the ModuleEnvironment.
 
     metadata_->memoryUsage = env_->memoryUsage;
+    metadata_->temporaryHasGcTypes = env_->gcTypesEnabled;
     metadata_->minMemoryLength = env_->minMemoryLength;
     metadata_->maxMemoryLength = env_->maxMemoryLength;
     metadata_->startFuncIndex = env_->startFuncIndex;
diff --git a/js/src/wasm/WasmInstance.cpp b/js/src/wasm/WasmInstance.cpp
index dedcb4f5001a..adea424b2407 100644
--- a/js/src/wasm/WasmInstance.cpp
+++ b/js/src/wasm/WasmInstance.cpp
@@ -133,6 +133,10 @@ Instance::callImport(JSContext* cx, uint32_t funcImportIndex, unsigned argc, con
           case ValType::F64:
             args[i].set(JS::CanonicalizedDoubleValue(*(double*)&argv[i]));
             break;
+          case ValType::AnyRef: {
+            args[i].set(ObjectOrNullValue(*(JSObject**)&argv[i]));
+            break;
+          }
           case ValType::I64:
           case ValType::I8x16:
           case ValType::I16x8:
@@ -188,23 +192,28 @@ Instance::callImport(JSContext* cx, uint32_t funcImportIndex, unsigned argc, con
     if (!TypeScript::ThisTypes(script)->hasType(TypeSet::UndefinedType()))
         return true;
 
+    // Functions with anyref in signature don't have a jit exit at the moment.
+    if (fi.sig().temporarilyUnsupportedAnyRef())
+        return true;
+
     const ValTypeVector& importArgs = fi.sig().args();
 
     size_t numKnownArgs = Min(importArgs.length(), importFun->nargs());
     for (uint32_t i = 0; i < numKnownArgs; i++) {
         TypeSet::Type type = TypeSet::UnknownType();
         switch (importArgs[i]) {
-          case ValType::I32:   type = TypeSet::Int32Type(); break;
-          case ValType::F32:   type = TypeSet::DoubleType(); break;
-          case ValType::F64:   type = TypeSet::DoubleType(); break;
-          case ValType::I64:   MOZ_CRASH("NYI");
-          case ValType::I8x16: MOZ_CRASH("NYI");
-          case ValType::I16x8: MOZ_CRASH("NYI");
-          case ValType::I32x4: MOZ_CRASH("NYI");
-          case ValType::F32x4: MOZ_CRASH("NYI");
-          case ValType::B8x16: MOZ_CRASH("NYI");
-          case ValType::B16x8: MOZ_CRASH("NYI");
-          case ValType::B32x4: MOZ_CRASH("NYI");
+          case ValType::I32:    type = TypeSet::Int32Type(); break;
+          case ValType::F32:    type = TypeSet::DoubleType(); break;
+          case ValType::F64:    type = TypeSet::DoubleType(); break;
+          case ValType::AnyRef: MOZ_CRASH("case guarded above");
+          case ValType::I64:    MOZ_CRASH("NYI");
+          case ValType::I8x16:  MOZ_CRASH("NYI");
+          case ValType::I16x8:  MOZ_CRASH("NYI");
+          case ValType::I32x4:  MOZ_CRASH("NYI");
+          case ValType::F32x4:  MOZ_CRASH("NYI");
+          case ValType::B8x16:  MOZ_CRASH("NYI");
+          case ValType::B16x8:  MOZ_CRASH("NYI");
+          case ValType::B32x4:  MOZ_CRASH("NYI");
         }
         if (!TypeScript::ArgTypes(script, i)->hasType(type))
             return true;
@@ -265,6 +274,31 @@ Instance::callImport_f64(Instance* instance, int32_t funcImportIndex, int32_t ar
     return ToNumber(cx, rval, (double*)argv);
 }
 
+static bool
+ToRef(JSContext* cx, HandleValue val, void* addr)
+{
+    if (val.isNull()) {
+        *(JSObject**)addr = nullptr;
+        return true;
+    }
+
+    JSObject* obj = ToObject(cx, val);
+    if (!obj)
+        return false;
+    *(JSObject**)addr = obj;
+    return true;
+}
+
+/* static */ int32_t
+Instance::callImport_ref(Instance* instance, int32_t funcImportIndex, int32_t argc, uint64_t* argv)
+{
+    JSContext* cx = TlsContext.get();
+    RootedValue rval(cx);
+    if (!instance->callImport(cx, funcImportIndex, argc, argv, &rval))
+        return false;
+    return ToRef(cx, rval, argv);
+}
+
 /* static */ uint32_t
 Instance::growMemory_i32(Instance* instance, uint32_t delta)
 {
@@ -672,6 +706,11 @@ Instance::callExport(JSContext* cx, uint32_t funcIndex, CallArgs args)
             if (!ToNumber(cx, v, (double*)&exportArgs[i]))
                 return false;
             break;
+          case ValType::AnyRef: {
+            if (!ToRef(cx, v, &exportArgs[i]))
+                return false;
+            break;
+          }
           case ValType::I8x16: {
             SimdConstant simd;
             if (!ToSimdConstant<Int8x16>(cx, v, &simd))
@@ -755,6 +794,8 @@ Instance::callExport(JSContext* cx, uint32_t funcIndex, CallArgs args)
     }
 
     void* retAddr = &exportArgs[0];
+
+    bool expectsObject = false;
     JSObject* retObj = nullptr;
     switch (func.sig().ret()) {
       case ExprType::Void:
@@ -771,6 +812,10 @@ Instance::callExport(JSContext* cx, uint32_t funcIndex, CallArgs args)
       case ExprType::F64:
         args.rval().set(NumberValue(*(double*)retAddr));
         break;
+      case ExprType::AnyRef:
+        retObj = *(JSObject**)retAddr;
+        expectsObject = true;
+        break;
       case ExprType::I8x16:
         retObj = CreateSimd<Int8x16>(cx, (int8_t*)retAddr);
         if (!retObj)
@@ -810,7 +855,9 @@ Instance::callExport(JSContext* cx, uint32_t funcIndex, CallArgs args)
         MOZ_CRASH("Limit");
     }
 
-    if (retObj)
+    if (expectsObject)
+        args.rval().set(ObjectOrNullValue(retObj));
+    else if (retObj)
         args.rval().set(ObjectValue(*retObj));
 
     return true;
diff --git a/js/src/wasm/WasmInstance.h b/js/src/wasm/WasmInstance.h
index 2ea6fe795442..6f7c7620476b 100644
--- a/js/src/wasm/WasmInstance.h
+++ b/js/src/wasm/WasmInstance.h
@@ -164,6 +164,7 @@ class Instance
     static int32_t callImport_i32(Instance*, int32_t, int32_t, uint64_t*);
     static int32_t callImport_i64(Instance*, int32_t, int32_t, uint64_t*);
     static int32_t callImport_f64(Instance*, int32_t, int32_t, uint64_t*);
+    static int32_t callImport_ref(Instance*, int32_t, int32_t, uint64_t*);
     static uint32_t growMemory_i32(Instance* instance, uint32_t delta);
     static uint32_t currentMemory_i32(Instance* instance);
     static int32_t wait_i32(Instance* instance, uint32_t byteOffset, int32_t value, int64_t timeout);
diff --git a/js/src/wasm/WasmIonCompile.cpp b/js/src/wasm/WasmIonCompile.cpp
index 07be484ccdd3..72c3d7693842 100644
--- a/js/src/wasm/WasmIonCompile.cpp
+++ b/js/src/wasm/WasmIonCompile.cpp
@@ -219,6 +219,9 @@ class FunctionCompiler
               case ValType::F64:
                 ins = MConstant::New(alloc(), DoubleValue(0.0), MIRType::Double);
                 break;
+              case ValType::AnyRef:
+                MOZ_CRASH("ion support for anyref locale default value NYI");
+                break;
               case ValType::I8x16:
                 ins = MSimdConstant::New(alloc(), SimdConstant::SplatX16(0), MIRType::Int8x16);
                 break;
@@ -2980,6 +2983,7 @@ SimdToLaneType(ValType type)
       case ValType::I64:
       case ValType::F32:
       case ValType::F64:
+      case ValType::AnyRef:
         break;
     }
     MOZ_CRASH("bad simd type");
@@ -3260,6 +3264,7 @@ EmitSimdCtor(FunctionCompiler& f, ValType type)
       case ValType::I64:
       case ValType::F32:
       case ValType::F64:
+      case ValType::AnyRef:
         break;
     }
     MOZ_CRASH("unexpected SIMD type");
@@ -3973,6 +3978,11 @@ EmitBodyExprs(FunctionCompiler& f)
           case uint16_t(Op::F64ReinterpretI64):
             CHECK(EmitReinterpret(f, ValType::F64, ValType::I64, MIRType::Double));
 
+          // GC types are NYI in Ion.
+          case uint16_t(Op::RefNull):
+          case uint16_t(Op::RefIsNull):
+            return f.iter().unrecognizedOpcode(&op);
+
           // Sign extensions
 #ifdef ENABLE_WASM_SIGNEXTEND_OPS
           case uint16_t(Op::I32Extend8S):
@@ -4386,7 +4396,7 @@ wasm::IonCompileFunctions(const ModuleEnvironment& env, LifoAlloc& lifo,
         ValTypeVector locals;
         if (!locals.appendAll(env.funcSigs[func.index]->args()))
             return false;
-        if (!DecodeLocalEntries(d, env.kind, &locals))
+        if (!DecodeLocalEntries(d, env.kind, env.gcTypesEnabled, &locals))
             return false;
 
         // Set up for Ion compilation.
diff --git a/js/src/wasm/WasmJS.cpp b/js/src/wasm/WasmJS.cpp
index 2a3cecf2d884..3321e432d386 100644
--- a/js/src/wasm/WasmJS.cpp
+++ b/js/src/wasm/WasmJS.cpp
@@ -1291,11 +1291,23 @@ WasmInstanceObject::getExportedFunction(JSContext* cx, HandleWasmInstanceObject
         RootedAtom name(cx, NumberToAtom(cx, funcIndex));
         if (!name)
             return false;
+
+        // Functions with anyref don't have jit entries yet, so they should
+        // mostly behave like asm.js functions. Pretend it's the case, until
+        // jit entries are implemented.
+        JSFunction::Flags flags = sig.temporarilyUnsupportedAnyRef()
+                                ? JSFunction::ASMJS_NATIVE
+                                : JSFunction::WASM_FUN;
+
         fun.set(NewNativeFunction(cx, WasmCall, numArgs, name, gc::AllocKind::FUNCTION_EXTENDED,
-                                  SingletonObject, JSFunction::WASM_FUN));
+                                  SingletonObject, flags));
         if (!fun)
             return false;
-        fun->setWasmJitEntry(instance.code().getAddressOfJitEntry(funcIndex));
+
+        if (sig.temporarilyUnsupportedAnyRef())
+            fun->setAsmJSIndex(funcIndex);
+        else
+            fun->setWasmJitEntry(instance.code().getAddressOfJitEntry(funcIndex));
     }
 
     fun->setExtendedSlot(FunctionExtended::WASM_INSTANCE_SLOT, ObjectValue(*instanceObj));
diff --git a/js/src/wasm/WasmModule.cpp b/js/src/wasm/WasmModule.cpp
index 1ef54f77be38..350ef02f33df 100644
--- a/js/src/wasm/WasmModule.cpp
+++ b/js/src/wasm/WasmModule.cpp
@@ -271,8 +271,10 @@ Module::finishTier2(UniqueLinkDataTier linkData2, UniqueCodeTier tier2, ModuleEn
                 return false;
         }
 
+        HasGcTypes gcTypesEnabled = code().metadata().temporaryHasGcTypes;
+
         Maybe<size_t> stub2Index;
-        if (!stubs2->createTier2(funcExportIndices, *tier2, &stub2Index))
+        if (!stubs2->createTier2(gcTypesEnabled, funcExportIndices, *tier2, &stub2Index))
             return false;
 
         // Install the data in the data structures. They will not be visible
diff --git a/js/src/wasm/WasmStubs.cpp b/js/src/wasm/WasmStubs.cpp
index a91a5dbedd11..657de9805cf7 100644
--- a/js/src/wasm/WasmStubs.cpp
+++ b/js/src/wasm/WasmStubs.cpp
@@ -92,6 +92,10 @@ SetupABIArguments(MacroAssembler& masm, const FuncExport& fe, Register argv, Reg
                 masm.load32(src, iter->gpr());
             else if (type == MIRType::Int64)
                 masm.load64(src, iter->gpr64());
+            else if (type == MIRType::Pointer)
+                masm.loadPtr(src, iter->gpr());
+            else
+                MOZ_CRASH("unknown GPR type");
             break;
 #ifdef JS_CODEGEN_REGISTER_PAIR
           case ABIArg::GPR_PAIR:
@@ -148,6 +152,10 @@ SetupABIArguments(MacroAssembler& masm, const FuncExport& fe, Register argv, Reg
 #endif
                 break;
               }
+              case MIRType::Pointer:
+                masm.loadPtr(src, scratch);
+                masm.storePtr(scratch, Address(masm.getStackPointer(), iter->offsetFromArgBase()));
+                break;
               case MIRType::Double:
                 masm.loadDouble(src, ScratchDoubleReg);
                 masm.storeDouble(ScratchDoubleReg,
@@ -204,6 +212,9 @@ StoreABIReturn(MacroAssembler& masm, const FuncExport& fe, Register argv)
         masm.canonicalizeDouble(ReturnDoubleReg);
         masm.storeDouble(ReturnDoubleReg, Address(argv, 0));
         break;
+      case ExprType::AnyRef:
+        masm.storePtr(ReturnReg, Address(argv, 0));
+        break;
       case ExprType::I8x16:
       case ExprType::I16x8:
       case ExprType::I32x4:
@@ -255,13 +266,20 @@ static const unsigned NonVolatileRegsPushSize = NonVolatileRegs.gprs().size() *
                                                 NonVolatileRegs.fpus().getPushSizeInBytes();
 #endif
 
-#if defined(JS_CODEGEN_ARM64)
-// Stacks are 16-byte aligned, hence the extra word.
-static const unsigned FramePushedBeforeAlign = NonVolatileRegsPushSize + 2 * sizeof(void*);
+#ifdef ENABLE_WASM_GC
+static const unsigned NumExtraPushed = 2; // tls and argv
 #else
-static const unsigned FramePushedBeforeAlign = NonVolatileRegsPushSize + sizeof(void*);
+static const unsigned NumExtraPushed = 1; // argv
 #endif
 
+#ifdef JS_CODEGEN_ARM64
+static const unsigned WasmPushSize = 16;
+#else
+static const unsigned WasmPushSize = sizeof(void*);
+#endif
+
+static const unsigned FramePushedBeforeAlign = NonVolatileRegsPushSize + NumExtraPushed * WasmPushSize;
+
 static void
 AssertExpectedSP(const MacroAssembler& masm)
 {
@@ -276,7 +294,7 @@ WasmPush(MacroAssembler& masm, const Operand& op)
 {
 #ifdef JS_CODEGEN_ARM64
     // Allocate a pad word so that SP can remain properly aligned.
-    masm.reserveStack(16);
+    masm.reserveStack(WasmPushSize);
     masm.storePtr(op, Address(masm.getStackPointer(), 0));
 #else
     masm.Push(op);
@@ -289,7 +307,7 @@ WasmPop(MacroAssembler& masm, Register r)
 #ifdef JS_CODEGEN_ARM64
     // Also pop the pad word allocated by WasmPush.
     masm.loadPtr(Address(masm.getStackPointer(), 0), r);
-    masm.freeStack(16);
+    masm.freeStack(WasmPushSize);
 #else
     masm.Pop(r);
 #endif
@@ -303,6 +321,17 @@ MoveSPForJitABI(MacroAssembler& masm)
 #endif
 }
 
+#ifdef ENABLE_WASM_GC
+static void
+SuppressGC(MacroAssembler& masm, int32_t increment, Register scratch)
+{
+    masm.loadPtr(Address(WasmTlsReg, offsetof(TlsData, cx)), scratch);
+    masm.add32(Imm32(increment),
+               Address(scratch, offsetof(JSContext, suppressGC) +
+                                js::ThreadLocalData<int32_t>::offsetOfValue()));
+}
+#endif
+
 static void
 CallFuncExport(MacroAssembler& masm, const FuncExport& fe, const Maybe<ImmPtr>& funcPtr)
 {
@@ -319,7 +348,7 @@ CallFuncExport(MacroAssembler& masm, const FuncExport& fe, const Maybe<ImmPtr>&
 // must map from the ABI of ExportFuncPtr to the export's signature's ABI.
 static bool
 GenerateInterpEntry(MacroAssembler& masm, const FuncExport& fe, const Maybe<ImmPtr>& funcPtr,
-                    Offsets* offsets)
+                    HasGcTypes gcTypesEnabled, Offsets* offsets)
 {
     AssertExpectedSP(masm);
     masm.haltingAlign(CodeAlignment);
@@ -372,6 +401,12 @@ GenerateInterpEntry(MacroAssembler& masm, const FuncExport& fe, const Maybe<ImmP
     else
         masm.loadPtr(Address(masm.getStackPointer(), argBase + arg.offsetFromArgBase()), WasmTlsReg);
 
+#ifdef ENABLE_WASM_GC
+    WasmPush(masm, WasmTlsReg);
+    if (gcTypesEnabled == HasGcTypes::True)
+        SuppressGC(masm, 1, scratch);
+#endif
+
     // Save 'argv' on the stack so that we can recover it after the call.
     WasmPush(masm, argv);
 
@@ -425,6 +460,12 @@ GenerateInterpEntry(MacroAssembler& masm, const FuncExport& fe, const Maybe<ImmP
     // Recover the 'argv' pointer which was saved before aligning the stack.
     WasmPop(masm, argv);
 
+#ifdef ENABLE_WASM_GC
+    WasmPop(masm, WasmTlsReg);
+    if (gcTypesEnabled == HasGcTypes::True)
+        SuppressGC(masm, -1, WasmTlsReg);
+#endif
+
     // Store the return value in argv[0].
     StoreABIReturn(masm, fe, argv);
 
@@ -451,7 +492,7 @@ GenerateInterpEntry(MacroAssembler& masm, const FuncExport& fe, const Maybe<ImmP
     MOZ_ASSERT(masm.framePushed() == 0);
 
 #if defined(JS_CODEGEN_ARM64)
-    masm.setFramePushed(16);
+    masm.setFramePushed(WasmPushSize);
     WasmPop(masm, lr);
     masm.abiret();
 #else
@@ -528,7 +569,7 @@ GenerateJitEntryThrow(MacroAssembler& masm, unsigned frameSize)
 
 static bool
 GenerateJitEntry(MacroAssembler& masm, size_t funcExportIndex, const FuncExport& fe,
-                 const Maybe<ImmPtr>& funcPtr, Offsets* offsets)
+                 const Maybe<ImmPtr>& funcPtr, HasGcTypes gcTypesEnabled, Offsets* offsets)
 {
     AssertExpectedSP(masm);
 
@@ -540,7 +581,15 @@ GenerateJitEntry(MacroAssembler& masm, size_t funcExportIndex, const FuncExport&
     // left):
     // <-- retAddr | descriptor | callee | argc | this | arg1..N
 
-    unsigned normalBytesNeeded = StackArgBytes(fe.sig().args());
+#ifdef ENABLE_WASM_GC
+    // Save WasmTlsReg in the uppermost part of the reserved area, because we
+    // need it directly after the call.
+    unsigned savedTlsSize = AlignBytes(sizeof(void*), WasmStackAlignment);
+#else
+    unsigned savedTlsSize = 0;
+#endif
+
+    unsigned normalBytesNeeded = StackArgBytes(fe.sig().args()) + savedTlsSize;
 
     MIRTypeVector coerceArgTypes;
     MOZ_ALWAYS_TRUE(coerceArgTypes.append(MIRType::Int32));
@@ -554,6 +603,10 @@ GenerateJitEntry(MacroAssembler& masm, size_t funcExportIndex, const FuncExport&
     // instruction.
     unsigned frameSize = StackDecrementForCall(WasmStackAlignment, 0, bytesNeeded);
 
+#ifdef ENABLE_WASM_GC
+    unsigned savedTlsOffset = frameSize - sizeof(void*);
+#endif
+
     // Reserve stack space for wasm ABI arguments, set up like this:
     // <-- ABI args | padding
     masm.reserveStack(frameSize);
@@ -726,12 +779,26 @@ GenerateJitEntry(MacroAssembler& masm, size_t funcExportIndex, const FuncExport&
     // Setup wasm register state.
     masm.loadWasmPinnedRegsFromTls();
 
+#ifdef ENABLE_WASM_GC
+    if (gcTypesEnabled == HasGcTypes::True) {
+        masm.storePtr(WasmTlsReg, Address(sp, savedTlsOffset));
+        SuppressGC(masm, 1, ScratchIonEntry);
+    }
+#endif
+
     // Call into the real function. Note that, due to the throw stub, fp, tls
     // and pinned registers may be clobbered.
     masm.assertStackAlignment(WasmStackAlignment);
     CallFuncExport(masm, fe, funcPtr);
     masm.assertStackAlignment(WasmStackAlignment);
 
+#ifdef ENABLE_WASM_GC
+    if (gcTypesEnabled == HasGcTypes::True) {
+        masm.loadPtr(Address(sp, savedTlsOffset), WasmTlsReg);
+        SuppressGC(masm, -1, WasmTlsReg);
+    }
+#endif
+
     // If fp is equal to the FailFP magic value (set by the throw stub), then
     // report the exception to the JIT caller by jumping into the exception
     // stub; otherwise the FP value is still set to the parent ion frame value.
@@ -758,6 +825,9 @@ GenerateJitEntry(MacroAssembler& masm, size_t funcExportIndex, const FuncExport&
         masm.canonicalizeDouble(ReturnDoubleReg);
         masm.boxDouble(ReturnDoubleReg, JSReturnOperand, ScratchDoubleReg);
         break;
+      case ExprType::AnyRef:
+        MOZ_CRASH("return anyref in jitentry NYI");
+        break;
       case ExprType::I64:
       case ExprType::I8x16:
       case ExprType::I16x8:
@@ -845,6 +915,9 @@ StackCopy(MacroAssembler& masm, MIRType type, Register scratch, Address src, Add
         masm.load64(src, scratch64);
         masm.store64(scratch64, dst);
 #endif
+    } else if (type == MIRType::Pointer) {
+        masm.loadPtr(src, scratch);
+        masm.storePtr(scratch, dst);
     } else if (type == MIRType::Float32) {
         masm.loadFloat32(src, ScratchFloat32Reg);
         masm.storeFloat32(ScratchFloat32Reg, dst);
@@ -878,8 +951,10 @@ FillArgumentArray(MacroAssembler& masm, const ValTypeVector& args, unsigned argO
                     masm.breakpoint();
                 else
                     masm.store64(i->gpr64(), dst);
-            } else {
-                MOZ_CRASH("unexpected input type?");
+            } else if (type == MIRType::Pointer) {
+                if (toValue)
+                    MOZ_CRASH("generating a jit exit for anyref NYI");
+                masm.storePtr(i->gpr(), dst);
             }
             break;
 #ifdef JS_CODEGEN_REGISTER_PAIR
@@ -926,6 +1001,8 @@ FillArgumentArray(MacroAssembler& masm, const ValTypeVector& args, unsigned argO
                 } else if (type == MIRType::Int64) {
                     // We can't box int64 into Values (yet).
                     masm.breakpoint();
+                } else if (type == MIRType::Pointer) {
+                    MOZ_CRASH("generating a jit exit for anyref NYI");
                 } else {
                     MOZ_ASSERT(IsFloatingPointType(type));
                     if (type == MIRType::Float32) {
@@ -1122,6 +1199,11 @@ GenerateImportInterpExit(MacroAssembler& masm, const FuncImport& fi, uint32_t fu
         masm.branchTest32(Assembler::Zero, ReturnReg, ReturnReg, throwLabel);
         masm.loadDouble(argv, ReturnDoubleReg);
         break;
+      case ExprType::AnyRef:
+        masm.call(SymbolicAddress::CallImport_Ref);
+        masm.branchTest32(Assembler::Zero, ReturnReg, ReturnReg, throwLabel);
+        masm.loadPtr(argv, ReturnReg);
+        break;
       case ExprType::I8x16:
       case ExprType::I16x8:
       case ExprType::I32x4:
@@ -1297,6 +1379,9 @@ GenerateImportJitExit(MacroAssembler& masm, const FuncImport& fi, Label* throwLa
       case ExprType::F64:
         masm.convertValueToDouble(JSReturnOperand, ReturnDoubleReg, &oolConvert);
         break;
+      case ExprType::AnyRef:
+        MOZ_CRASH("anyref returned by import (jit exit) NYI");
+        break;
       case ExprType::I8x16:
       case ExprType::I16x8:
       case ExprType::I32x4:
@@ -1701,21 +1786,22 @@ GenerateDebugTrapStub(MacroAssembler& masm, Label* throwLabel, CallableOffsets*
 
 bool
 wasm::GenerateEntryStubs(MacroAssembler& masm, size_t funcExportIndex, const FuncExport& fe,
-                         const Maybe<ImmPtr>& callee, bool isAsmJS, CodeRangeVector* codeRanges)
+                         const Maybe<ImmPtr>& callee, bool isAsmJS, HasGcTypes gcTypesEnabled,
+                         CodeRangeVector* codeRanges)
 {
     MOZ_ASSERT(!callee == fe.hasEagerStubs());
     MOZ_ASSERT_IF(isAsmJS, fe.hasEagerStubs());
 
     Offsets offsets;
-    if (!GenerateInterpEntry(masm, fe, callee, &offsets))
+    if (!GenerateInterpEntry(masm, fe, callee, gcTypesEnabled, &offsets))
         return false;
     if (!codeRanges->emplaceBack(CodeRange::InterpEntry, fe.funcIndex(), offsets))
         return false;
 
-    if (isAsmJS)
+    if (isAsmJS || fe.sig().temporarilyUnsupportedAnyRef())
         return true;
 
-    if (!GenerateJitEntry(masm, funcExportIndex, fe, callee, &offsets))
+    if (!GenerateJitEntry(masm, funcExportIndex, fe, callee, gcTypesEnabled, &offsets))
         return false;
     if (!codeRanges->emplaceBack(CodeRange::JitEntry, fe.funcIndex(), offsets))
         return false;
@@ -1748,6 +1834,9 @@ wasm::GenerateStubs(const ModuleEnvironment& env, const FuncImportVector& import
         if (!code->codeRanges.emplaceBack(CodeRange::ImportInterpExit, funcIndex, interpOffsets))
             return false;
 
+        if (fi.sig().temporarilyUnsupportedAnyRef())
+            continue;
+
         JitExitOffsets jitOffsets;
         if (!GenerateImportJitExit(masm, fi, &throwLabel, &jitOffsets))
             return false;
@@ -1762,8 +1851,11 @@ wasm::GenerateStubs(const ModuleEnvironment& env, const FuncImportVector& import
         const FuncExport& fe = exports[i];
         if (!fe.hasEagerStubs())
             continue;
-        if (!GenerateEntryStubs(masm, i, fe, noAbsolute, env.isAsmJS(), &code->codeRanges))
+        if (!GenerateEntryStubs(masm, i, fe, noAbsolute, env.isAsmJS(),
+                                env.gcTypesEnabled, &code->codeRanges))
+        {
             return false;
+        }
     }
 
     JitSpew(JitSpew_Codegen, "# Emitting wasm exit stubs");
diff --git a/js/src/wasm/WasmStubs.h b/js/src/wasm/WasmStubs.h
index 7b8d7fd7fea6..6dc3d0b20a11 100644
--- a/js/src/wasm/WasmStubs.h
+++ b/js/src/wasm/WasmStubs.h
@@ -39,7 +39,7 @@ GenerateStubs(const ModuleEnvironment& env, const FuncImportVector& imports,
 extern bool
 GenerateEntryStubs(jit::MacroAssembler& masm, size_t funcExportIndex,
                    const FuncExport& funcExport, const Maybe<jit::ImmPtr>& callee,
-                   bool isAsmJS, CodeRangeVector* codeRanges);
+                   bool isAsmJS, HasGcTypes gcTypesEnabled, CodeRangeVector* codeRanges);
 
 } // namespace wasm
 } // namespace js
diff --git a/js/src/wasm/WasmTextToBinary.cpp b/js/src/wasm/WasmTextToBinary.cpp
index a895737dea05..2f9900c7905e 100644
--- a/js/src/wasm/WasmTextToBinary.cpp
+++ b/js/src/wasm/WasmTextToBinary.cpp
@@ -115,6 +115,7 @@ class WasmToken
         Offset,
         OpenParen,
         Param,
+        RefNull,
         Result,
         Return,
         SetGlobal,
@@ -331,6 +332,7 @@ class WasmToken
           case Load:
           case Loop:
           case Nop:
+          case RefNull:
           case Return:
           case SetGlobal:
           case SetLocal:
@@ -888,6 +890,8 @@ WasmTokenStream::next()
             return WasmToken(WasmToken::Align, begin, cur_);
         if (consume(u"anyfunc"))
             return WasmToken(WasmToken::AnyFunc, begin, cur_);
+        if (consume(u"anyref"))
+            return WasmToken(WasmToken::ValueType, ValType::AnyRef, begin, cur_);
 #ifdef ENABLE_WASM_THREAD_OPS
         if (consume(u"atomic.wake"))
             return WasmToken(WasmToken::Wake, ThreadOp::Wake, begin, cur_);
@@ -1665,6 +1669,13 @@ WasmTokenStream::next()
             return WasmToken(WasmToken::Result, begin, cur_);
         if (consume(u"return"))
             return WasmToken(WasmToken::Return, begin, cur_);
+        if (consume(u"ref.")) {
+            if (consume(u"null"))
+                return WasmToken(WasmToken::RefNull, begin, cur_);
+            if (consume(u"is_null"))
+                return WasmToken(WasmToken::UnaryOpcode, Op::RefIsNull, begin, cur_);
+            break;
+        }
         break;
 
       case 's':
@@ -2932,6 +2943,19 @@ ParseGrowMemory(WasmParseContext& c, bool inParens)
     return new(c.lifo) AstGrowMemory(operand);
 }
 
+static AstExpr*
+ParseRefNull(WasmParseContext& c)
+{
+    WasmToken token;
+    if (!c.ts.match(WasmToken::ValueType, &token, c.error))
+        return nullptr;
+    if (token.valueType() != ValType::AnyRef) {
+        c.ts.generateError(token, "only anyref is supported for nullref", c.error);
+        return nullptr;
+    }
+    return new(c.lifo) AstRefNull(ValType::AnyRef);
+}
+
 static AstExpr*
 ParseExprBody(WasmParseContext& c, WasmToken token, bool inParens)
 {
@@ -3008,6 +3032,8 @@ ParseExprBody(WasmParseContext& c, WasmToken token, bool inParens)
         return new(c.lifo) AstCurrentMemory();
       case WasmToken::GrowMemory:
         return ParseGrowMemory(c, inParens);
+      case WasmToken::RefNull:
+        return ParseRefNull(c);
       default:
         c.ts.generateError(token, c.error);
         return nullptr;
@@ -4325,6 +4351,7 @@ ResolveExpr(Resolver& r, AstExpr& expr)
       case AstExprKind::Pop:
       case AstExprKind::Unreachable:
       case AstExprKind::CurrentMemory:
+      case AstExprKind::RefNull:
         return true;
       case AstExprKind::Drop:
         return ResolveDropOperator(r, expr.as<AstDrop>());
@@ -4929,6 +4956,13 @@ EncodeWake(Encoder& e, AstWake& s)
            EncodeLoadStoreFlags(e, s.address());
 }
 
+static bool
+EncodeRefNull(Encoder& e, AstRefNull& s)
+{
+    return e.writeOp(Op::RefNull) &&
+           e.writeValType(s.refType());
+}
+
 static bool
 EncodeExpr(Encoder& e, AstExpr& expr)
 {
@@ -4939,6 +4973,8 @@ EncodeExpr(Encoder& e, AstExpr& expr)
         return e.writeOp(Op::Nop);
       case AstExprKind::Unreachable:
         return e.writeOp(Op::Unreachable);
+      case AstExprKind::RefNull:
+        return EncodeRefNull(e, expr.as<AstRefNull>());
       case AstExprKind::BinaryOperator:
         return EncodeBinaryOperator(e, expr.as<AstBinaryOperator>());
       case AstExprKind::Block:
diff --git a/js/src/wasm/WasmTypes.cpp b/js/src/wasm/WasmTypes.cpp
index 91ee92a4c278..c97e1cfebd94 100644
--- a/js/src/wasm/WasmTypes.cpp
+++ b/js/src/wasm/WasmTypes.cpp
@@ -72,6 +72,9 @@ Val::writePayload(uint8_t* dst) const
       case ValType::B32x4:
         memcpy(dst, &u, jit::Simd128DataSize);
         return;
+      case ValType::AnyRef:
+        // TODO
+        MOZ_CRASH("writing imported value of AnyRef in global NYI");
     }
 }
 
@@ -172,7 +175,7 @@ static const unsigned sTotalBits = sizeof(ImmediateType) * 8;
 static const unsigned sTagBits = 1;
 static const unsigned sReturnBit = 1;
 static const unsigned sLengthBits = 4;
-static const unsigned sTypeBits = 2;
+static const unsigned sTypeBits = 3;
 static const unsigned sMaxTypes = (sTotalBits - sTagBits - sReturnBit - sLengthBits) / sTypeBits;
 
 static bool
@@ -183,6 +186,7 @@ IsImmediateType(ValType vt)
       case ValType::I64:
       case ValType::F32:
       case ValType::F64:
+      case ValType::AnyRef:
         return true;
       case ValType::I8x16:
       case ValType::I16x8:
@@ -199,7 +203,7 @@ IsImmediateType(ValType vt)
 static unsigned
 EncodeImmediateType(ValType vt)
 {
-    static_assert(3 < (1 << sTypeBits), "fits");
+    static_assert(4 < (1 << sTypeBits), "fits");
     switch (vt) {
       case ValType::I32:
         return 0;
@@ -209,6 +213,8 @@ EncodeImmediateType(ValType vt)
         return 2;
       case ValType::F64:
         return 3;
+      case ValType::AnyRef:
+        return 4;
       case ValType::I8x16:
       case ValType::I16x8:
       case ValType::I32x4:
diff --git a/js/src/wasm/WasmTypes.h b/js/src/wasm/WasmTypes.h
index f43177d77649..0ef026f340a0 100644
--- a/js/src/wasm/WasmTypes.h
+++ b/js/src/wasm/WasmTypes.h
@@ -183,9 +183,10 @@ SizeOf(ValType vt)
       case ValType::B16x8:
       case ValType::B32x4:
         return 16;
-      default:
-        MOZ_CRASH("Invalid ValType");
+      case ValType::AnyRef:
+        MOZ_CRASH("unexpected anyref");
     }
+    MOZ_CRASH("Invalid ValType");
 }
 
 static inline bool
@@ -275,21 +276,34 @@ static inline jit::MIRType
 ToMIRType(ValType vt)
 {
     switch (vt) {
-      case ValType::I32: return jit::MIRType::Int32;
-      case ValType::I64: return jit::MIRType::Int64;
-      case ValType::F32: return jit::MIRType::Float32;
-      case ValType::F64: return jit::MIRType::Double;
-      case ValType::I8x16: return jit::MIRType::Int8x16;
-      case ValType::I16x8: return jit::MIRType::Int16x8;
-      case ValType::I32x4: return jit::MIRType::Int32x4;
-      case ValType::F32x4: return jit::MIRType::Float32x4;
-      case ValType::B8x16: return jit::MIRType::Bool8x16;
-      case ValType::B16x8: return jit::MIRType::Bool16x8;
-      case ValType::B32x4: return jit::MIRType::Bool32x4;
+      case ValType::I32:    return jit::MIRType::Int32;
+      case ValType::I64:    return jit::MIRType::Int64;
+      case ValType::F32:    return jit::MIRType::Float32;
+      case ValType::F64:    return jit::MIRType::Double;
+      case ValType::AnyRef: return jit::MIRType::Pointer;
+      case ValType::I8x16:  return jit::MIRType::Int8x16;
+      case ValType::I16x8:  return jit::MIRType::Int16x8;
+      case ValType::I32x4:  return jit::MIRType::Int32x4;
+      case ValType::F32x4:  return jit::MIRType::Float32x4;
+      case ValType::B8x16:  return jit::MIRType::Bool8x16;
+      case ValType::B16x8:  return jit::MIRType::Bool16x8;
+      case ValType::B32x4:  return jit::MIRType::Bool32x4;
     }
     MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE("bad type");
 }
 
+static inline bool
+IsRefType(ValType vt)
+{
+    return vt == ValType::AnyRef;
+}
+
+static inline bool
+IsNumberType(ValType vt)
+{
+    return !IsRefType(vt);
+}
+
 // The ExprType enum represents the type of a WebAssembly expression or return
 // value and may either be a value type or void. Soon, expression types will be
 // generalized to a list of ValType and this enum will go away, replaced,
@@ -297,22 +311,23 @@ ToMIRType(ValType vt)
 
 enum class ExprType
 {
-    Void  = uint8_t(TypeCode::BlockVoid),
+    Void   = uint8_t(TypeCode::BlockVoid),
 
-    I32   = uint8_t(TypeCode::I32),
-    I64   = uint8_t(TypeCode::I64),
-    F32   = uint8_t(TypeCode::F32),
-    F64   = uint8_t(TypeCode::F64),
+    I32    = uint8_t(TypeCode::I32),
+    I64    = uint8_t(TypeCode::I64),
+    F32    = uint8_t(TypeCode::F32),
+    F64    = uint8_t(TypeCode::F64),
+    AnyRef = uint8_t(TypeCode::AnyRef),
 
-    I8x16 = uint8_t(TypeCode::I8x16),
-    I16x8 = uint8_t(TypeCode::I16x8),
-    I32x4 = uint8_t(TypeCode::I32x4),
-    F32x4 = uint8_t(TypeCode::F32x4),
-    B8x16 = uint8_t(TypeCode::B8x16),
-    B16x8 = uint8_t(TypeCode::B16x8),
-    B32x4 = uint8_t(TypeCode::B32x4),
+    I8x16  = uint8_t(TypeCode::I8x16),
+    I16x8  = uint8_t(TypeCode::I16x8),
+    I32x4  = uint8_t(TypeCode::I32x4),
+    F32x4  = uint8_t(TypeCode::F32x4),
+    B8x16  = uint8_t(TypeCode::B8x16),
+    B16x8  = uint8_t(TypeCode::B16x8),
+    B32x4  = uint8_t(TypeCode::B32x4),
 
-    Limit = uint8_t(TypeCode::Limit)
+    Limit  = uint8_t(TypeCode::Limit)
 };
 
 static inline bool
@@ -350,18 +365,19 @@ static inline const char*
 ToCString(ExprType type)
 {
     switch (type) {
-      case ExprType::Void:  return "void";
-      case ExprType::I32:   return "i32";
-      case ExprType::I64:   return "i64";
-      case ExprType::F32:   return "f32";
-      case ExprType::F64:   return "f64";
-      case ExprType::I8x16: return "i8x16";
-      case ExprType::I16x8: return "i16x8";
-      case ExprType::I32x4: return "i32x4";
-      case ExprType::F32x4: return "f32x4";
-      case ExprType::B8x16: return "b8x16";
-      case ExprType::B16x8: return "b16x8";
-      case ExprType::B32x4: return "b32x4";
+      case ExprType::Void:    return "void";
+      case ExprType::I32:     return "i32";
+      case ExprType::I64:     return "i64";
+      case ExprType::F32:     return "f32";
+      case ExprType::F64:     return "f64";
+      case ExprType::AnyRef:  return "anyref";
+      case ExprType::I8x16:   return "i8x16";
+      case ExprType::I16x8:   return "i16x8";
+      case ExprType::I32x4:   return "i32x4";
+      case ExprType::F32x4:   return "f32x4";
+      case ExprType::B8x16:   return "b8x16";
+      case ExprType::B16x8:   return "b16x8";
+      case ExprType::B32x4:   return "b32x4";
       case ExprType::Limit:;
     }
     MOZ_CRASH("bad expression type");
@@ -450,6 +466,12 @@ enum class Shareable
     True
 };
 
+enum class HasGcTypes
+{
+    False,
+    True
+};
+
 // The Val class represents a single WebAssembly value of a given value type,
 // mostly for the purpose of numeric literals and initializers. A Val does not
 // directly map to a JS value since there is not (currently) a precise
@@ -569,8 +591,17 @@ class Sig
     bool hasI64ArgOrRet() const {
         if (ret() == ExprType::I64)
             return true;
-        for (ValType a : args()) {
-            if (a == ValType::I64)
+        for (ValType arg : args()) {
+            if (arg == ValType::I64)
+                return true;
+        }
+        return false;
+    }
+    bool temporarilyUnsupportedAnyRef() const {
+        if (ret() == ExprType::AnyRef)
+            return true;
+        for (ValType arg : args()) {
+            if (arg == ValType::AnyRef)
                 return true;
         }
         return false;
@@ -1437,6 +1468,7 @@ enum class SymbolicAddress
     CallImport_I32,
     CallImport_I64,
     CallImport_F64,
+    CallImport_Ref,
     CoerceInPlace_ToInt32,
     CoerceInPlace_ToNumber,
     CoerceInPlace_JitEntry,
diff --git a/js/src/wasm/WasmValidate.cpp b/js/src/wasm/WasmValidate.cpp
index 99ffe20fd991..6c4f98c896a2 100644
--- a/js/src/wasm/WasmValidate.cpp
+++ b/js/src/wasm/WasmValidate.cpp
@@ -302,7 +302,7 @@ wasm::EncodeLocalEntries(Encoder& e, const ValTypeVector& locals)
 }
 
 static bool
-DecodeValType(Decoder& d, ModuleKind kind, ValType* type)
+DecodeValType(Decoder& d, ModuleKind kind, HasGcTypes gcTypesEnabled, ValType* type)
 {
     uint8_t unchecked;
     if (!d.readValType(&unchecked))
@@ -315,6 +315,11 @@ DecodeValType(Decoder& d, ModuleKind kind, ValType* type)
       case uint8_t(ValType::I64):
         *type = ValType(unchecked);
         return true;
+      case uint8_t(ValType::AnyRef):
+        if (gcTypesEnabled == HasGcTypes::False)
+            break;
+        *type = ValType(unchecked);
+        return true;
       case uint8_t(ValType::I8x16):
       case uint8_t(ValType::I16x8):
       case uint8_t(ValType::I32x4):
@@ -333,7 +338,8 @@ DecodeValType(Decoder& d, ModuleKind kind, ValType* type)
 }
 
 bool
-wasm::DecodeLocalEntries(Decoder& d, ModuleKind kind, ValTypeVector* locals)
+wasm::DecodeLocalEntries(Decoder& d, ModuleKind kind, HasGcTypes gcTypesEnabled,
+                         ValTypeVector* locals)
 {
     uint32_t numLocalEntries;
     if (!d.readVarU32(&numLocalEntries))
@@ -348,7 +354,7 @@ wasm::DecodeLocalEntries(Decoder& d, ModuleKind kind, ValTypeVector* locals)
             return d.fail("too many locals");
 
         ValType type;
-        if (!DecodeValType(d, kind, &type))
+        if (!DecodeValType(d, kind, gcTypesEnabled, &type))
             return false;
 
         if (!locals->appendN(type, count))
@@ -742,6 +748,20 @@ DecodeFunctionBodyExprs(const ModuleEnvironment& env, const Sig& sig, const ValT
             return iter.unrecognizedOpcode(&op);
 #endif
           }
+#ifdef ENABLE_WASM_GC
+          case uint16_t(Op::RefNull): {
+            if (env.gcTypesEnabled == HasGcTypes::False)
+                return iter.unrecognizedOpcode(&op);
+            CHECK(iter.readRefNull());
+            break;
+          }
+          case uint16_t(Op::RefIsNull): {
+            if (env.gcTypesEnabled == HasGcTypes::False)
+                return iter.unrecognizedOpcode(&op);
+            CHECK(iter.readConversion(ValType::AnyRef, ValType::I32, &nothing));
+            break;
+          }
+#endif
           case uint16_t(Op::ThreadPrefix): {
 #ifdef ENABLE_WASM_THREAD_OPS
             switch (op.b1) {
@@ -936,7 +956,7 @@ wasm::ValidateFunctionBody(const ModuleEnvironment& env, uint32_t funcIndex, uin
 
     const uint8_t* bodyBegin = d.currentPosition();
 
-    if (!DecodeLocalEntries(d, ModuleKind::Wasm, &locals))
+    if (!DecodeLocalEntries(d, ModuleKind::Wasm, env.gcTypesEnabled, &locals))
         return false;
 
     if (!DecodeFunctionBodyExprs(env, sig, locals, bodyBegin + bodySize, &d))
@@ -1001,7 +1021,7 @@ DecodeTypeSection(Decoder& d, ModuleEnvironment* env)
             return false;
 
         for (uint32_t i = 0; i < numArgs; i++) {
-            if (!DecodeValType(d, ModuleKind::Wasm, &args[i]))
+            if (!DecodeValType(d, ModuleKind::Wasm, env->gcTypesEnabled, &args[i]))
                 return false;
         }
 
@@ -1016,7 +1036,7 @@ DecodeTypeSection(Decoder& d, ModuleEnvironment* env)
 
         if (numRets == 1) {
             ValType type;
-            if (!DecodeValType(d, ModuleKind::Wasm, &type))
+            if (!DecodeValType(d, ModuleKind::Wasm, env->gcTypesEnabled, &type))
                 return false;
 
             result = ToExprType(type);
@@ -1161,7 +1181,8 @@ GlobalIsJSCompatible(Decoder& d, ValType type, bool isMutable)
 static bool
 DecodeGlobalType(Decoder& d, ValType* type, bool* isMutable)
 {
-    if (!DecodeValType(d, ModuleKind::Wasm, type))
+    // No gc types in globals at the moment.
+    if (!DecodeValType(d, ModuleKind::Wasm, HasGcTypes::False, type))
         return false;
 
     uint8_t flags;
@@ -1980,7 +2001,13 @@ wasm::Validate(JSContext* cx, const ShareableBytes& bytecode, UniqueChars* error
 {
     Decoder d(bytecode.bytes, 0, error);
 
-    ModuleEnvironment env(CompileMode::Once, Tier::Ion, DebugEnabled::False,
+#ifdef ENABLE_WASM_GC
+    HasGcTypes gcSupport = cx->options().wasmGc() ? HasGcTypes::True : HasGcTypes::False;
+#else
+    HasGcTypes gcSupport = HasGcTypes::False;
+#endif
+
+    ModuleEnvironment env(CompileMode::Once, Tier::Ion, DebugEnabled::False, gcSupport,
                           cx->compartment()->creationOptions().getSharedMemoryAndAtomicsEnabled()
                           ? Shareable::True
                           : Shareable::False);
diff --git a/js/src/wasm/WasmValidate.h b/js/src/wasm/WasmValidate.h
index dbd8db356518..4cf679deb533 100644
--- a/js/src/wasm/WasmValidate.h
+++ b/js/src/wasm/WasmValidate.h
@@ -60,6 +60,7 @@ struct ModuleEnvironment
     const ModuleKind          kind;
     const CompileMode         mode;
     const Shareable           sharedMemoryEnabled;
+    const HasGcTypes          gcTypesEnabled;
     const Tier                tier;
 
     // Module fields decoded from the module environment (or initialized while
@@ -87,12 +88,14 @@ struct ModuleEnvironment
     explicit ModuleEnvironment(CompileMode mode,
                                Tier tier,
                                DebugEnabled debug,
+                               HasGcTypes hasGcTypes,
                                Shareable sharedMemoryEnabled,
                                ModuleKind kind = ModuleKind::Wasm)
       : debug(debug),
         kind(kind),
         mode(mode),
         sharedMemoryEnabled(sharedMemoryEnabled),
+        gcTypesEnabled(hasGcTypes),
         tier(tier),
         memoryUsage(MemoryUsage::None),
         minMemoryLength(0)
@@ -696,7 +699,7 @@ MOZ_MUST_USE bool
 EncodeLocalEntries(Encoder& d, const ValTypeVector& locals);
 
 MOZ_MUST_USE bool
-DecodeLocalEntries(Decoder& d, ModuleKind kind, ValTypeVector* locals);
+DecodeLocalEntries(Decoder& d, ModuleKind kind, HasGcTypes gcTypesEnabled, ValTypeVector* locals);
 
 // Returns whether the given [begin, end) prefix of a module's bytecode starts a
 // code section and, if so, returns the SectionRange of that code section.
diff --git a/js/xpconnect/src/XPCJSContext.cpp b/js/xpconnect/src/XPCJSContext.cpp
index bc1290c4ea1c..17e029ab39a3 100644
--- a/js/xpconnect/src/XPCJSContext.cpp
+++ b/js/xpconnect/src/XPCJSContext.cpp
@@ -773,6 +773,9 @@ ReloadPrefsCallback(const char* pref, void* data)
     bool useWasm = Preferences::GetBool(JS_OPTIONS_DOT_STR "wasm");
     bool useWasmIon = Preferences::GetBool(JS_OPTIONS_DOT_STR "wasm_ionjit");
     bool useWasmBaseline = Preferences::GetBool(JS_OPTIONS_DOT_STR "wasm_baselinejit");
+#ifdef ENABLE_WASM_GC
+    bool useWasmGc = Preferences::GetBool(JS_OPTIONS_DOT_STR "wasm_gc");
+#endif
     bool throwOnAsmJSValidationFailure = Preferences::GetBool(JS_OPTIONS_DOT_STR
                                                               "throw_on_asmjs_validation_failure");
     bool useNativeRegExp = Preferences::GetBool(JS_OPTIONS_DOT_STR "native_regexp");
@@ -844,6 +847,9 @@ ReloadPrefsCallback(const char* pref, void* data)
                              .setWasm(useWasm)
                              .setWasmIon(useWasmIon)
                              .setWasmBaseline(useWasmBaseline)
+#ifdef ENABLE_WASM_GC
+                             .setWasmGc(useWasmGc)
+#endif
                              .setThrowOnAsmJSValidationFailure(throwOnAsmJSValidationFailure)
                              .setNativeRegExp(useNativeRegExp)
                              .setAsyncStack(useAsyncStack)
diff --git a/js/xpconnect/src/moz.build b/js/xpconnect/src/moz.build
index c30bd297342f..2b473d2a4b6a 100644
--- a/js/xpconnect/src/moz.build
+++ b/js/xpconnect/src/moz.build
@@ -63,3 +63,6 @@ LOCAL_INCLUDES += [
 
 if CONFIG['CC_TYPE'] in ('clang', 'gcc'):
     CXXFLAGS += ['-Wno-shadow', '-Werror=format']
+
+if CONFIG['NIGHTLY_BUILD']:
+    DEFINES['ENABLE_WASM_GC'] = True
diff --git a/layout/generic/MathMLTextRunFactory.cpp b/layout/generic/MathMLTextRunFactory.cpp
index daf6462a1e4e..452dd614af38 100644
--- a/layout/generic/MathMLTextRunFactory.cpp
+++ b/layout/generic/MathMLTextRunFactory.cpp
@@ -636,7 +636,7 @@ MathMLTextRunFactory::RebuildTextRun(nsTransformedTextRun* aTextRun,
       // This overrides the initial values specified in fontStyle, to avoid
       // inconsistencies in which attributes allow CSS changes and which do not.
       if (mFlags & MATH_FONT_WEIGHT_BOLD) {
-        font.weight = NS_FONT_WEIGHT_BOLD;
+        font.weight = FontWeight::Bold();
         if (mFlags & MATH_FONT_STYLING_NORMAL) {
           font.style = NS_FONT_STYLE_NORMAL;
         } else {
@@ -644,7 +644,7 @@ MathMLTextRunFactory::RebuildTextRun(nsTransformedTextRun* aTextRun,
         }
       } else if (mFlags & MATH_FONT_STYLING_NORMAL) {
         font.style = NS_FONT_STYLE_NORMAL;
-        font.weight = NS_FONT_WEIGHT_NORMAL;
+        font.weight = FontWeight::Normal();
       } else {
         mathVar = NS_MATHML_MATHVARIANT_ITALIC;
       }
@@ -723,20 +723,20 @@ MathMLTextRunFactory::RebuildTextRun(nsTransformedTextRun* aTextRun,
 
   if (mathVar == NS_MATHML_MATHVARIANT_BOLD && doMathvariantStyling) {
     font.style = NS_FONT_STYLE_NORMAL;
-    font.weight = NS_FONT_WEIGHT_BOLD;
+    font.weight = FontWeight::Bold();
   } else if (mathVar == NS_MATHML_MATHVARIANT_ITALIC && doMathvariantStyling) {
     font.style = NS_FONT_STYLE_ITALIC;
-    font.weight = NS_FONT_WEIGHT_NORMAL;
+    font.weight = FontWeight::Normal();
   } else if (mathVar == NS_MATHML_MATHVARIANT_BOLD_ITALIC &&
              doMathvariantStyling) {
     font.style = NS_FONT_STYLE_ITALIC;
-    font.weight = NS_FONT_WEIGHT_BOLD;
+    font.weight = FontWeight::Bold();
   } else if (mathVar != NS_MATHML_MATHVARIANT_NONE) {
     // Mathvariant overrides fontstyle and fontweight
     // Need to check to see if mathvariant is actually applied as this function
     // is used for other purposes.
     font.style = NS_FONT_STYLE_NORMAL;
-    font.weight = NS_FONT_WEIGHT_NORMAL;
+    font.weight = FontWeight::Normal();
   }
   gfxFontGroup* newFontGroup = nullptr;
 
diff --git a/layout/style/FontFace.h b/layout/style/FontFace.h
index cf7e0a448afd..00ad5e4d353a 100644
--- a/layout/style/FontFace.h
+++ b/layout/style/FontFace.h
@@ -8,6 +8,7 @@
 #define mozilla_dom_FontFace_h
 
 #include "mozilla/dom/FontFaceBinding.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "gfxUserFontSet.h"
 #include "nsAutoPtr.h"
 #include "nsCSSPropertyID.h"
@@ -47,7 +48,7 @@ public:
   public:
     Entry(gfxUserFontSet* aFontSet,
           const nsTArray<gfxFontFaceSrc>& aFontFaceSrcList,
-          uint32_t aWeight,
+          FontWeight aWeight,
           int32_t aStretch,
           uint8_t aStyle,
           const nsTArray<gfxFontFeature>& aFeatureSettings,
diff --git a/layout/style/FontFaceSet.cpp b/layout/style/FontFaceSet.cpp
index 17641c89300e..130127a94cf9 100644
--- a/layout/style/FontFaceSet.cpp
+++ b/layout/style/FontFaceSet.cpp
@@ -15,6 +15,7 @@
 #include "mozilla/dom/FontFaceSetLoadEvent.h"
 #include "mozilla/dom/FontFaceSetLoadEventBinding.h"
 #include "mozilla/dom/Promise.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/net/ReferrerPolicy.h"
 #include "mozilla/AsyncEventDispatcher.h"
 #include "mozilla/Logging.h"
@@ -205,7 +206,7 @@ void
 FontFaceSet::ParseFontShorthandForMatching(
                             const nsAString& aFont,
                             RefPtr<SharedFontList>& aFamilyList,
-                            uint32_t& aWeight,
+                            FontWeight& aWeight,
                             int32_t& aStretch,
                             uint8_t& aStyle,
                             ErrorResult& aRv)
@@ -219,7 +220,12 @@ FontFaceSet::ParseFontShorthandForMatching(
     aRv.Throw(NS_ERROR_DOM_SYNTAX_ERR);
     return;
   }
-  aWeight = weight.GetIntValue();
+  if (weight.GetUnit() == eCSSUnit_FontWeight) {
+    aWeight = weight.GetFontWeight();
+  } else {
+    MOZ_ASSERT(weight.GetUnit() == eCSSUnit_Enumerated);
+    aWeight = FontWeight(weight.GetIntValue());
+  }
   aStretch = stretch.GetIntValue();
   aStyle = style.GetIntValue();
 }
@@ -247,7 +253,7 @@ FontFaceSet::FindMatchingFontFaces(const nsAString& aFont,
                                    ErrorResult& aRv)
 {
   RefPtr<SharedFontList> familyList;
-  uint32_t weight;
+  FontWeight weight;
   int32_t stretch;
   uint8_t italicStyle;
   ParseFontShorthandForMatching(aFont, familyList, weight, stretch, italicStyle,
@@ -972,7 +978,7 @@ FontFaceSet::FindOrCreateUserFontEntryFromFontFace(const nsAString& aFamilyName,
   nsCSSValue val;
   nsCSSUnit unit;
 
-  uint32_t weight = NS_FONT_WEIGHT_NORMAL;
+  FontWeight weight = FontWeight::Normal();
   int32_t stretch = NS_STYLE_FONT_STRETCH_NORMAL;
   uint8_t italicStyle = NS_STYLE_FONT_STYLE_NORMAL;
   uint32_t languageOverride = NO_FONT_LANGUAGE_OVERRIDE;
@@ -981,18 +987,19 @@ FontFaceSet::FindOrCreateUserFontEntryFromFontFace(const nsAString& aFamilyName,
   // set up weight
   aFontFace->GetDesc(eCSSFontDesc_Weight, val);
   unit = val.GetUnit();
-  if (unit == eCSSUnit_Integer || unit == eCSSUnit_Enumerated) {
-    weight = val.GetIntValue();
-    if (weight == 0) {
-      weight = NS_FONT_WEIGHT_NORMAL;
-    }
+  if (unit == eCSSUnit_FontWeight) {
+    weight = val.GetFontWeight();
+  } else if (unit == eCSSUnit_Enumerated) {
+    weight = FontWeight(val.GetIntValue());
   } else if (unit == eCSSUnit_Normal) {
-    weight = NS_FONT_WEIGHT_NORMAL;
+    weight = FontWeight::Normal();
   } else {
-    NS_ASSERTION(unit == eCSSUnit_Null,
-                 "@font-face weight has unexpected unit");
+    MOZ_ASSERT(unit == eCSSUnit_Null, "@font-face weight has unexpected unit");
   }
 
+  if (weight == FontWeight(0)) {
+    weight = FontWeight::Normal();
+  }
   // set up stretch
   aFontFace->GetDesc(eCSSFontDesc_Stretch, val);
   unit = val.GetUnit();
@@ -1243,25 +1250,13 @@ FontFaceSet::LogMessage(gfxUserFontEntry* aUserFontEntry,
   nsAutoCString fontURI;
   aUserFontEntry->GetFamilyNameAndURIForLogging(familyName, fontURI);
 
-  char weightKeywordBuf[8]; // plenty to sprintf() a uint16_t
-  const char* weightKeyword;
-  const nsCString& weightKeywordString =
-    nsCSSProps::ValueToKeyword(aUserFontEntry->Weight(),
-                               nsCSSProps::kFontWeightKTable);
-  if (weightKeywordString.Length() > 0) {
-    weightKeyword = weightKeywordString.get();
-  } else {
-    SprintfLiteral(weightKeywordBuf, "%u", aUserFontEntry->Weight());
-    weightKeyword = weightKeywordBuf;
-  }
-
   nsPrintfCString message
        ("downloadable font: %s "
-        "(font-family: \"%s\" style:%s weight:%s stretch:%s src index:%d)",
+        "(font-family: \"%s\" style:%s weight:%g stretch:%s src index:%d)",
         aMessage,
         familyName.get(),
         aUserFontEntry->IsItalic() ? "italic" : "normal",
-        weightKeyword,
+        aUserFontEntry->Weight().ToFloat(),
         nsCSSProps::ValueToKeyword(aUserFontEntry->Stretch(),
                                    nsCSSProps::kFontStretchKTable).get(),
         aUserFontEntry->GetSrcIndex());
@@ -1934,7 +1929,7 @@ FontFaceSet::UserFontSet::DoRebuildUserFontSet()
 /* virtual */ already_AddRefed<gfxUserFontEntry>
 FontFaceSet::UserFontSet::CreateUserFontEntry(
                                const nsTArray<gfxFontFaceSrc>& aFontFaceSrcList,
-                               uint32_t aWeight,
+                               FontWeight aWeight,
                                int32_t aStretch,
                                uint8_t aStyle,
                                const nsTArray<gfxFontFeature>& aFeatureSettings,
diff --git a/layout/style/FontFaceSet.h b/layout/style/FontFaceSet.h
index ec4d1675a24e..3195922433da 100644
--- a/layout/style/FontFaceSet.h
+++ b/layout/style/FontFaceSet.h
@@ -10,6 +10,7 @@
 #include "mozilla/dom/FontFace.h"
 #include "mozilla/dom/FontFaceSetBinding.h"
 #include "mozilla/DOMEventTargetHelper.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "gfxUserFontSet.h"
 #include "nsICSSLoaderObserver.h"
 
@@ -95,9 +96,9 @@ public:
                                 uint32_t aFlags = nsIScriptError::errorFlag,
                                 nsresult aStatus = NS_OK) override;
     virtual void DoRebuildUserFontSet() override;
-    virtual already_AddRefed<gfxUserFontEntry> CreateUserFontEntry(
+    already_AddRefed<gfxUserFontEntry> CreateUserFontEntry(
                                    const nsTArray<gfxFontFaceSrc>& aFontFaceSrcList,
-                                   uint32_t aWeight,
+                                   FontWeight aWeight,
                                    int32_t aStretch,
                                    uint8_t aStyle,
                                    const nsTArray<gfxFontFeature>& aFeatureSettings,
@@ -312,7 +313,7 @@ private:
   void ParseFontShorthandForMatching(
               const nsAString& aFont,
               RefPtr<SharedFontList>& aFamilyList,
-              uint32_t& aWeight,
+              FontWeight& aWeight,
               int32_t& aStretch,
               uint8_t& aStyle,
               ErrorResult& aRv);
diff --git a/layout/style/ServoBindings.cpp b/layout/style/ServoBindings.cpp
index 621d98d7be10..cadcf7ee0eae 100644
--- a/layout/style/ServoBindings.cpp
+++ b/layout/style/ServoBindings.cpp
@@ -52,6 +52,7 @@
 #include "mozilla/EffectCompositor.h"
 #include "mozilla/EffectSet.h"
 #include "mozilla/EventStates.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/Keyframe.h"
 #include "mozilla/Mutex.h"
 #include "mozilla/Preferences.h"
@@ -1327,6 +1328,19 @@ Gecko_nsFont_SetFontFeatureValuesLookup(nsFont* aFont,
   aFont->featureValueLookup = aPresContext->GetFontFeatureValuesLookup();
 }
 
+float
+Gecko_FontWeight_ToFloat(mozilla::FontWeight aWeight)
+{
+  return aWeight.ToFloat();
+}
+
+void
+Gecko_FontWeight_SetFloat(mozilla::FontWeight* aWeight,
+                          float aFloat)
+{
+  *aWeight = mozilla::FontWeight(aFloat);
+}
+
 void
 Gecko_nsFont_ResetFontFeatureValuesLookup(nsFont* aFont)
 {
@@ -2306,6 +2320,13 @@ Gecko_CSSValue_Drop(nsCSSValueBorrowedMut aCSSValue)
   aCSSValue->~nsCSSValue();
 }
 
+void
+Gecko_CSSValue_SetFontWeight(nsCSSValueBorrowedMut aCSSValue,
+                             float weight)
+{
+  aCSSValue->SetFontWeight(mozilla::FontWeight(weight));
+}
+
 void
 Gecko_nsStyleFont_SetLang(nsStyleFont* aFont, nsAtom* aAtom)
 {
diff --git a/layout/style/ServoBindings.h b/layout/style/ServoBindings.h
index ce326cd76bb8..85b9d4118466 100644
--- a/layout/style/ServoBindings.h
+++ b/layout/style/ServoBindings.h
@@ -565,6 +565,7 @@ void Gecko_CSSValue_SetKeyword(nsCSSValueBorrowedMut css_value, nsCSSKeyword key
 void Gecko_CSSValue_SetPercentage(nsCSSValueBorrowedMut css_value, float percent);
 void Gecko_CSSValue_SetPixelLength(nsCSSValueBorrowedMut aCSSValue, float aLen);
 void Gecko_CSSValue_SetCalc(nsCSSValueBorrowedMut css_value, nsStyleCoord::CalcValue calc);
+void Gecko_CSSValue_SetFontWeight(nsCSSValueBorrowedMut css_value, float weight);
 void Gecko_CSSValue_SetFunction(nsCSSValueBorrowedMut css_value, int32_t len);
 void Gecko_CSSValue_SetString(nsCSSValueBorrowedMut css_value,
                               const uint8_t* string, uint32_t len, nsCSSUnit unit);
@@ -584,6 +585,10 @@ void Gecko_CSSValue_InitSharedList(nsCSSValueBorrowedMut css_value, uint32_t len
 void Gecko_CSSValue_Drop(nsCSSValueBorrowedMut css_value);
 NS_DECL_THREADSAFE_FFI_REFCOUNTING(nsCSSValueSharedList, CSSValueSharedList);
 
+float Gecko_FontWeight_ToFloat(mozilla::FontWeight aWeight);
+void Gecko_FontWeight_SetFloat(mozilla::FontWeight* aWeight,
+                               float aFloatValue);
+
 void Gecko_nsStyleFont_SetLang(nsStyleFont* font, nsAtom* atom);
 void Gecko_nsStyleFont_CopyLangFrom(nsStyleFont* aFont, const nsStyleFont* aSource);
 void Gecko_nsStyleFont_FixupNoneGeneric(nsStyleFont* font,
diff --git a/layout/style/ServoBindings.toml b/layout/style/ServoBindings.toml
index 0519270bdcc4..95a2131099c6 100644
--- a/layout/style/ServoBindings.toml
+++ b/layout/style/ServoBindings.toml
@@ -463,6 +463,7 @@ structs-types = [
     "mozilla::dom::CallerType",
     "mozilla::AnonymousCounterStyle",
     "mozilla::AtomArray",
+    "mozilla::FontWeight",
     "mozilla::MallocSizeOf",
     "mozilla::OriginFlags",
     "mozilla::UniquePtr",
diff --git a/layout/style/nsCSSValue.cpp b/layout/style/nsCSSValue.cpp
index b678f2744601..50434480deb4 100644
--- a/layout/style/nsCSSValue.cpp
+++ b/layout/style/nsCSSValue.cpp
@@ -9,6 +9,7 @@
 #include "nsCSSValue.h"
 
 #include "mozilla/CORSMode.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/ServoBindings.h"
 #include "mozilla/ServoStyleSet.h"
 #include "mozilla/ServoTypes.h"
@@ -121,6 +122,12 @@ nsCSSValue::nsCSSValue(SharedFontList* aValue)
   mValue.mFontFamilyList->AddRef();
 }
 
+nsCSSValue::nsCSSValue(FontWeight aWeight)
+  : mUnit(eCSSUnit_FontWeight)
+{
+  mValue.mFontWeight = aWeight;
+}
+
 nsCSSValue::nsCSSValue(const nsCSSValue& aCopy)
   : mUnit(aCopy.mUnit)
 {
@@ -180,6 +187,9 @@ nsCSSValue::nsCSSValue(const nsCSSValue& aCopy)
     mValue.mFontFamilyList = aCopy.mValue.mFontFamilyList;
     mValue.mFontFamilyList->AddRef();
   }
+  else if (eCSSUnit_FontWeight == mUnit) {
+    mValue.mFontWeight = aCopy.mValue.mFontWeight;
+  }
   else if (eCSSUnit_AtomIdent == mUnit) {
     mValue.mAtom = aCopy.mValue.mAtom;
     mValue.mAtom->AddRef();
@@ -259,6 +269,9 @@ bool nsCSSValue::operator==(const nsCSSValue& aOther) const
       return mValue.mFontFamilyList->mNames ==
              aOther.mValue.mFontFamilyList->mNames;
     }
+    else if (eCSSUnit_FontWeight == mUnit) {
+      return mValue.mFontWeight == aOther.mValue.mFontWeight;
+    }
     else if (eCSSUnit_AtomIdent == mUnit) {
       return mValue.mAtom == aOther.mValue.mAtom;
     }
@@ -477,6 +490,13 @@ void nsCSSValue::SetFontFamilyListValue(already_AddRefed<SharedFontList> aValue)
   mValue.mFontFamilyList = aValue.take();
 }
 
+void nsCSSValue::SetFontWeight(FontWeight aWeight)
+{
+  Reset();
+  mUnit = eCSSUnit_FontWeight;
+  mValue.mFontWeight = aWeight;
+}
+
 void nsCSSValue::SetPairValue(const nsCSSValuePair* aValue)
 {
   // pairs should not be used for null/inherit/initial values
@@ -895,6 +915,7 @@ nsCSSValue::SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
     // Int: nothing extra to measure.
     case eCSSUnit_Integer:
     case eCSSUnit_Enumerated:
+    case eCSSUnit_FontWeight:
       break;
 
     // Float: nothing extra to measure.
diff --git a/layout/style/nsCSSValue.h b/layout/style/nsCSSValue.h
index 0ad50dbc0e67..d14e1dd1426b 100644
--- a/layout/style/nsCSSValue.h
+++ b/layout/style/nsCSSValue.h
@@ -11,6 +11,7 @@
 
 #include "mozilla/Attributes.h"
 #include "mozilla/CORSMode.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/ServoTypes.h"
 #include "mozilla/SheetType.h"
@@ -441,7 +442,10 @@ enum nsCSSUnit {
   eCSSUnit_Milliseconds = 3001,    // (float) 1/1000 second
 
   // Flexible fraction (CSS Grid)
-  eCSSUnit_FlexFraction = 4000     // (float) Fraction of free space
+  eCSSUnit_FlexFraction = 4000,    // (float) Fraction of free space
+
+  // Font property types
+  eCSSUnit_FontWeight   = 5000,    // An encoded font-weight
 };
 
 struct nsCSSValuePair;
@@ -476,6 +480,7 @@ public:
   explicit nsCSSValue(mozilla::css::ImageValue* aValue);
   explicit nsCSSValue(mozilla::css::GridTemplateAreasValue* aValue);
   explicit nsCSSValue(mozilla::SharedFontList* aValue);
+  explicit nsCSSValue(mozilla::FontWeight aWeight);
   nsCSSValue(const nsCSSValue& aCopy);
   nsCSSValue(nsCSSValue&& aOther)
     : mUnit(aOther.mUnit)
@@ -631,6 +636,12 @@ public:
     return mozilla::WrapNotNull(mValue.mFontFamilyList);
   }
 
+  mozilla::FontWeight GetFontWeight() const
+  {
+    MOZ_ASSERT(mUnit == eCSSUnit_FontWeight, "not a font weight value");
+    return mValue.mFontWeight;
+  }
+
   // bodies of these are below
   inline nsCSSValuePair& GetPairValue();
   inline const nsCSSValuePair& GetPairValue() const;
@@ -708,6 +719,7 @@ public:
   void SetImageValue(mozilla::css::ImageValue* aImage);
   void SetGridTemplateAreas(mozilla::css::GridTemplateAreasValue* aValue);
   void SetFontFamilyListValue(already_AddRefed<mozilla::SharedFontList> aFontListValue);
+  void SetFontWeight(mozilla::FontWeight aWeight);
   void SetPairValue(const nsCSSValuePair* aPair);
   void SetPairValue(const nsCSSValue& xValue, const nsCSSValue& yValue);
   void SetSharedListValue(nsCSSValueSharedList* aList);
@@ -784,6 +796,7 @@ protected:
     nsCSSValuePairList_heap* MOZ_OWNING_REF mPairList;
     nsCSSValuePairList* mPairListDependent;
     mozilla::SharedFontList* MOZ_OWNING_REF mFontFamilyList;
+    mozilla::FontWeight mFontWeight;
   } mValue;
 };
 
diff --git a/layout/style/nsComputedDOMStyle.cpp b/layout/style/nsComputedDOMStyle.cpp
index ace7d8153b54..87d31021e509 100644
--- a/layout/style/nsComputedDOMStyle.cpp
+++ b/layout/style/nsComputedDOMStyle.cpp
@@ -9,6 +9,7 @@
 #include "nsComputedDOMStyle.h"
 
 #include "mozilla/ArrayUtils.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/Preferences.h"
 
 #include "nsError.h"
@@ -1973,8 +1974,9 @@ nsComputedDOMStyle::DoGetFontWeight()
 
   const nsStyleFont* font = StyleFont();
 
-  uint16_t weight = font->mFont.weight;
-  NS_ASSERTION(weight % 100 == 0, "unexpected value of font-weight");
+  float weight = font->mFont.weight.ToFloat();
+  MOZ_ASSERT(1.0f <= weight && weight <= 1000.0f,
+             "unexpected font-weight value");
   val->SetNumber(weight);
 
   return val.forget();
diff --git a/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/TestRunnerActivity.java b/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/TestRunnerActivity.java
index 5255ee1868df..f6d0ce629bd0 100644
--- a/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/TestRunnerActivity.java
+++ b/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/TestRunnerActivity.java
@@ -21,8 +21,9 @@ public class TestRunnerActivity extends Activity {
 
     static GeckoRuntime sRuntime;
 
-    GeckoSession mSession;
-    GeckoView mView;
+    private GeckoSession mSession;
+    private GeckoView mView;
+    private boolean mKillProcessOnDestroy;
 
     private GeckoSession.NavigationDelegate mNavigationDelegate = new GeckoSession.NavigationDelegate() {
         @Override
@@ -113,6 +114,13 @@ public class TestRunnerActivity extends Activity {
             geckoSettings.setArguments(new String[] { "-purgecaches" });
             geckoSettings.setExtras(intent.getExtras());
             sRuntime = GeckoRuntime.create(this, geckoSettings);
+            sRuntime.setDelegate(new GeckoRuntime.Delegate() {
+                @Override
+                public void onShutdown() {
+                    mKillProcessOnDestroy = true;
+                    finish();
+                }
+            });
         }
 
         mSession = createSession();
@@ -133,6 +141,10 @@ public class TestRunnerActivity extends Activity {
     protected void onDestroy() {
         mSession.close();
         super.onDestroy();
+
+        if (mKillProcessOnDestroy) {
+            android.os.Process.killProcess(android.os.Process.myPid());
+        }
     }
 
     public GeckoView getGeckoView() {
diff --git a/mobile/android/geckoview/src/main/java/org/mozilla/geckoview/GeckoRuntime.java b/mobile/android/geckoview/src/main/java/org/mozilla/geckoview/GeckoRuntime.java
index fbf6cf80835f..63522a4aa9eb 100644
--- a/mobile/android/geckoview/src/main/java/org/mozilla/geckoview/GeckoRuntime.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/geckoview/GeckoRuntime.java
@@ -6,24 +6,19 @@
 
 package org.mozilla.geckoview;
 
-import java.util.ArrayList;
-
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.content.Context;
-import android.support.annotation.IntDef;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.util.Log;
 
-import org.mozilla.gecko.annotation.WrapForJNI;
 import org.mozilla.gecko.EventDispatcher;
 import org.mozilla.gecko.GeckoAppShell;
 import org.mozilla.gecko.GeckoThread;
 import org.mozilla.gecko.util.BundleEventListener;
 import org.mozilla.gecko.util.EventCallback;
 import org.mozilla.gecko.util.GeckoBundle;
-import org.mozilla.gecko.util.ThreadUtils;
 
 public final class GeckoRuntime implements Parcelable {
     private static final String LOGTAG = "GeckoRuntime";
@@ -53,6 +48,7 @@ public final class GeckoRuntime implements Parcelable {
     }
 
     private GeckoRuntimeSettings mSettings;
+    private Delegate mDelegate;
 
     /**
      * Attach the runtime to the given context.
@@ -69,6 +65,17 @@ public final class GeckoRuntime implements Parcelable {
         }
     }
 
+    private final BundleEventListener mEventListener = new BundleEventListener() {
+        @Override
+        public void handleMessage(final String event, final GeckoBundle message,
+                                  final EventCallback callback) {
+            if ("Gecko:Exited".equals(event) && mDelegate != null) {
+                mDelegate.onShutdown();
+                EventDispatcher.getInstance().unregisterUiThreadListener(mEventListener, "Gecko:Exited");
+            }
+        }
+    };
+
     /* package */ boolean init(final @NonNull GeckoRuntimeSettings settings) {
         if (DEBUG) {
             Log.d(LOGTAG, "init");
@@ -85,6 +92,9 @@ public final class GeckoRuntime implements Parcelable {
                 return false;
             }
             mSettings = settings;
+
+            // Bug 1453062 -- the EventDispatcher should really live here (or in GeckoThread)
+            EventDispatcher.getInstance().registerUiThreadListener(mEventListener, "Gecko:Exited");
             return true;
         }
         Log.d(LOGTAG, "init failed (could not initiate GeckoThread)");
@@ -146,6 +156,32 @@ public final class GeckoRuntime implements Parcelable {
         GeckoThread.forceQuit();
     }
 
+    public interface Delegate {
+        /**
+         * This is called when the runtime shuts down. Any GeckoSession instances that were
+         * opened with this instance are now considered closed.
+         **/
+        void onShutdown();
+    }
+
+    /**
+     * Set a delegate for receiving callbacks relevant to to this GeckoRuntime.
+     *
+     * @param delegate an implementation of {@link GeckoRuntime.Delegate}.
+     */
+    public void setDelegate(final Delegate delegate) {
+        mDelegate = delegate;
+    }
+
+    /**
+     * Returns the current delegate, if any.
+     *
+     * @return an instance of {@link GeckoRuntime.Delegate} or null if no delegate has been set.
+     */
+    public @Nullable Delegate getDelegate() {
+        return mDelegate;
+    }
+
     @Override // Parcelable
     public int describeContents() {
         return 0;
diff --git a/mobile/android/modules/geckoview/GeckoViewNavigation.jsm b/mobile/android/modules/geckoview/GeckoViewNavigation.jsm
index bb5e4aa8b751..b1b5c3785825 100644
--- a/mobile/android/modules/geckoview/GeckoViewNavigation.jsm
+++ b/mobile/android/modules/geckoview/GeckoViewNavigation.jsm
@@ -9,6 +9,9 @@ var EXPORTED_SYMBOLS = ["GeckoViewNavigation"];
 ChromeUtils.import("resource://gre/modules/GeckoViewModule.jsm");
 ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm");
 
+ChromeUtils.defineModuleGetter(this, "BrowserUtils",
+                               "resource://gre/modules/BrowserUtils.jsm");
+
 XPCOMUtils.defineLazyModuleGetters(this, {
   EventDispatcher: "resource://gre/modules/Messaging.jsm",
   LoadURIDelegate: "resource://gre/modules/LoadURIDelegate.jsm",
@@ -252,7 +255,7 @@ class GeckoViewNavigation extends GeckoViewModule {
   // nsIBrowserDOMWindow.
   canClose() {
     debug("canClose");
-    return false;
+    return true;
   }
 
   onEnable() {
diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index d76304175fd4..b12338d7b356 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -1396,6 +1396,9 @@ pref("javascript.options.asmjs",            true);
 pref("javascript.options.wasm",             true);
 pref("javascript.options.wasm_ionjit",      true);
 pref("javascript.options.wasm_baselinejit", true);
+#ifdef ENABLE_WASM_GC
+pref("javascript.options.wasm_gc",          false);
+#endif
 pref("javascript.options.native_regexp",    true);
 pref("javascript.options.parallel_parsing", true);
 #if !defined(RELEASE_OR_BETA) && !defined(ANDROID) && !defined(XP_IOS)
diff --git a/modules/libpref/moz.build b/modules/libpref/moz.build
index 931d334c1649..9e81d107b3ee 100644
--- a/modules/libpref/moz.build
+++ b/modules/libpref/moz.build
@@ -43,6 +43,9 @@ DEFINES['MOZ_WIDGET_TOOLKIT'] = CONFIG['MOZ_WIDGET_TOOLKIT']
 if CONFIG['MOZ_ENABLE_WEBRENDER']:
     DEFINES['MOZ_ENABLE_WEBRENDER'] = True
 
+if CONFIG['NIGHTLY_BUILD']:
+    DEFINES['ENABLE_WASM_GC'] = True
+
 FINAL_TARGET_PP_FILES += [
     'greprefs.js',
 ]
diff --git a/mozglue/linker/ElfLoader.cpp b/mozglue/linker/ElfLoader.cpp
index e0829846b625..994caa87affa 100644
--- a/mozglue/linker/ElfLoader.cpp
+++ b/mozglue/linker/ElfLoader.cpp
@@ -16,8 +16,14 @@
 #include "CustomElf.h"
 #include "Mappable.h"
 #include "Logging.h"
+#include "Utils.h"
 #include <inttypes.h>
 
+using namespace mozilla;
+
+// From Utils.h
+Atomic<size_t, ReleaseAcquire> gPageSize;
+
 #if defined(ANDROID)
 #include <sys/syscall.h>
 #include <math.h>
@@ -51,7 +57,6 @@ dl_iterate_phdr(dl_phdr_cb callback, void *data) __attribute__((weak));
  * containing this code. */
 extern "C" Elf::Dyn _DYNAMIC[];
 
-using namespace mozilla;
 
 /**
  * dlfcn.h replacements functions
diff --git a/mozglue/linker/Utils.h b/mozglue/linker/Utils.h
index 4be99f831f8a..1b61cac4ce22 100644
--- a/mozglue/linker/Utils.h
+++ b/mozglue/linker/Utils.h
@@ -11,6 +11,7 @@
 #include <sys/mman.h>
 #include <unistd.h>
 #include "mozilla/Assertions.h"
+#include "mozilla/Atomics.h"
 #include "mozilla/Scoped.h"
 
 /**
@@ -102,12 +103,18 @@ struct AutoCloseFILETraits
 };
 typedef mozilla::Scoped<AutoCloseFILETraits> AutoCloseFILE;
 
+extern mozilla::Atomic<size_t, mozilla::ReleaseAcquire> gPageSize;
+
 /**
  * Page alignment helpers
  */
-static inline size_t PageSize()
+static size_t PageSize()
 {
-  return 4096;
+  if (!gPageSize) {
+    gPageSize = sysconf(_SC_PAGESIZE);
+  }
+
+  return gPageSize;
 }
 
 static inline uintptr_t AlignedPtr(uintptr_t ptr, size_t alignment)
diff --git a/netwerk/base/ProxyAutoConfig.cpp b/netwerk/base/ProxyAutoConfig.cpp
index 2c965f8e8f4d..d562f321bb45 100644
--- a/netwerk/base/ProxyAutoConfig.cpp
+++ b/netwerk/base/ProxyAutoConfig.cpp
@@ -307,8 +307,9 @@ public:
   // nsITimerCallback
   NS_IMETHOD Notify(nsITimer *timer) override
   {
-    if (mRequest)
-      mRequest->Cancel(NS_ERROR_NET_TIMEOUT);
+    nsCOMPtr<nsICancelable> request(mRequest);
+    if (request)
+      request->Cancel(NS_ERROR_NET_TIMEOUT);
     mTimer = nullptr;
     return NS_OK;
   }
diff --git a/netwerk/base/nsNetUtil.cpp b/netwerk/base/nsNetUtil.cpp
index 7535eb60caa1..ca3a7a901f4f 100644
--- a/netwerk/base/nsNetUtil.cpp
+++ b/netwerk/base/nsNetUtil.cpp
@@ -2162,6 +2162,30 @@ bool NS_IsSameSiteForeign(nsIChannel* aChannel, nsIURI* aHostURI)
 
   bool isForeign = false;
   thirdPartyUtil->IsThirdPartyChannel(aChannel, uri, &isForeign);
+
+  // if we are dealing with a cross origin request, we can return here
+  // because we already know the request is 'foreign'.
+  if (isForeign) {
+    return true;
+  }
+
+  // for the purpose of same-site cookies we have to treat any cross-origin
+  // redirects as foreign. E.g. cross-site to same-site redirect is a problem
+  // with regards to CSRF.
+
+  nsCOMPtr<nsIPrincipal> redirectPrincipal;
+  nsCOMPtr<nsIURI> redirectURI;
+  for (nsIRedirectHistoryEntry* entry : loadInfo->RedirectChain()) {
+    entry->GetPrincipal(getter_AddRefs(redirectPrincipal));
+    if (redirectPrincipal) {
+      redirectPrincipal->GetURI(getter_AddRefs(redirectURI));
+      thirdPartyUtil->IsThirdPartyChannel(aChannel, redirectURI, &isForeign);
+      // if at any point we encounter a cross-origin redirect we can return.
+      if (isForeign) {
+        return true;
+      }
+    }
+  }
   return isForeign;
 }
 
diff --git a/security/manager/ssl/StaticHPKPins.h b/security/manager/ssl/StaticHPKPins.h
index 9a8458a7907b..5c204fab2fba 100644
--- a/security/manager/ssl/StaticHPKPins.h
+++ b/security/manager/ssl/StaticHPKPins.h
@@ -1163,4 +1163,4 @@ static const TransportSecurityPreload kPublicKeyPinningPreloadList[] = {
 
 static const int32_t kUnknownId = -1;
 
-static const PRTime kPreloadPKPinsExpirationTime = INT64_C(1532033020972000);
+static const PRTime kPreloadPKPinsExpirationTime = INT64_C(1532119521329000);
diff --git a/security/manager/ssl/nsSTSPreloadList.errors b/security/manager/ssl/nsSTSPreloadList.errors
index 7bc3e69890c1..9927fd307edc 100644
--- a/security/manager/ssl/nsSTSPreloadList.errors
+++ b/security/manager/ssl/nsSTSPreloadList.errors
@@ -1,6 +1,7 @@
 00220022.net: could not connect to host
 007-preisvergleich.de: could not connect to host
 007kf.com: could not connect to host
+00881919.com: could not connect to host
 00wbf.com: could not connect to host
 01100010011001010111001101110100.com: could not connect to host
 029inno.com: could not connect to host
@@ -20,7 +21,6 @@
 13826145000.com: could not connect to host
 13th-dover.uk: could not connect to host
 16164f.com: could not connect to host
-166166.com: could not connect to host
 1888zr.com: could not connect to host
 1912x.com: could not connect to host
 1921958389.rsc.cdn77.org: could not connect to host
@@ -50,7 +50,7 @@
 4loc.us: could not connect to host
 4web-hosting.com: could not connect to host
 5000yz.com: could not connect to host
-517vpn.cn: could not connect to host
+52kb.net: could not connect to host
 52kb1.com: could not connect to host
 52neptune.com: could not connect to host
 56877.com: could not connect to host
@@ -93,7 +93,7 @@ achterhoekseveiligheidsbeurs.nl: could not connect to host
 ackis.duckdns.org: could not connect to host
 acpinformatique.fr: could not connect to host
 acrossgw.com: could not connect to host
-activeworld.net: could not connect to host
+activeclearweb.com: could not connect to host
 ad-disruptio.fr: could not connect to host
 adamcoffee.net: could not connect to host
 adamdixon.co.uk: could not connect to host
@@ -117,6 +117,7 @@ agingstop.net: could not connect to host
 agoravm.tk: could not connect to host
 agowa.eu: could not connect to host
 agowa338.de: could not connect to host
+agrikulturchic.com: could not connect to host
 agrilinks.org: could not connect to host
 ahelos.tk: could not connect to host
 ahkubiak.ovh: could not connect to host
@@ -175,6 +176,7 @@ andrewdaws.info: could not connect to host
 andrewdaws.me: could not connect to host
 andrewdaws.tv: could not connect to host
 andrewrdaws.com: could not connect to host
+andys-place.co.uk: could not connect to host
 anecuni-club.com: could not connect to host
 anecuni-rec.com: could not connect to host
 angrydragonproductions.com: could not connect to host
@@ -219,6 +221,7 @@ artisense.de: could not connect to host
 artisticedgegranite.net: could not connect to host
 artofeyes.nl: could not connect to host
 ascii.moe: could not connect to host
+asdyx.de: could not connect to host
 ashleyadum.com: could not connect to host
 asisee.co.il: could not connect to host
 asphaltfruehling.de: could not connect to host
@@ -263,6 +266,7 @@ awan.tech: could not connect to host
 awei.pub: could not connect to host
 awf0.xyz: could not connect to host
 awxg.eu.org: could not connect to host
+axel-fischer.net: could not connect to host
 axel-fischer.science: could not connect to host
 axxial.tk: could not connect to host
 azuxul.fr: could not connect to host
@@ -271,9 +275,8 @@ b303.me: could not connect to host
 b9winner.com: could not connect to host
 babelfisch.eu: could not connect to host
 babystep.tv: could not connect to host
-bacimg.com: could not connect to host
+bad.horse: could not connect to host
 badbee.cc: could not connect to host
-bairdzhang.com: could not connect to host
 balonmano.co: could not connect to host
 bandally.net: could not connect to host
 bandarifamily.com: could not connect to host
@@ -332,6 +335,7 @@ bfrailwayclub.cf: could not connect to host
 bianinapiccanovias.com: could not connect to host
 bichonmaltes.com.br: could not connect to host
 bigerbio.com: could not connect to host
+billaud.eu.org: could not connect to host
 billigpoker.dk: could not connect to host
 binam.center: could not connect to host
 binaryabstraction.com: could not connect to host
@@ -384,6 +388,7 @@ boozinyan.com: could not connect to host
 bopera.co.uk: could not connect to host
 borchers-media.de: could not connect to host
 borisbesemer.com: could not connect to host
+bouncourseplanner.net: could not connect to host
 boxdevigneron.fr: could not connect to host
 bpadvisors.eu: could not connect to host
 bqcp.net: could not connect to host
@@ -486,6 +491,7 @@ charmyadesara.com: could not connect to host
 chatnbook.com: could not connect to host
 chatsworthelectrical.com: could not connect to host
 cheah.xyz: could not connect to host
+cheesefusion.com: could not connect to host
 chellame.fr: could not connect to host
 chez-janine.de: could not connect to host
 chicorycom.net: could not connect to host
@@ -497,7 +503,6 @@ chocolat-suisse.ch: could not connect to host
 chorkley.me: could not connect to host
 chrisebert.net: could not connect to host
 christianhoffmann.info: could not connect to host
-christianpusch.de: could not connect to host
 christiansayswords.com: could not connect to host
 christophersole.com: could not connect to host
 chromaryu.net: could not connect to host
@@ -518,9 +523,11 @@ clevelandokla.com: could not connect to host
 clic-music.com: could not connect to host
 clickomobile.com: could not connect to host
 clintonbloodworth.com: could not connect to host
+closeli.cn: could not connect to host
 closingholding.com: could not connect to host
 cloudberlin.goip.de: could not connect to host
 cloudbleed.info: could not connect to host
+cloudimproved.com: could not connect to host
 cloudwarez.xyz: could not connect to host
 clownish.co.il: could not connect to host
 clubmate.rocks: could not connect to host
@@ -555,6 +562,7 @@ colo-tech.com: could not connect to host
 com-in.de: could not connect to host
 com.cc: could not connect to host
 comiq.io: could not connect to host
+commania.co.kr: could not connect to host
 compeuphoria.com: could not connect to host
 complex-organization.com: could not connect to host
 complt.xyz: could not connect to host
@@ -562,9 +570,9 @@ comprehensiveihc.com: could not connect to host
 conception.sk: could not connect to host
 conejovalleyelectrical.com: could not connect to host
 conkret.in: could not connect to host
+conniesacademy.com: could not connect to host
 conrad.am: could not connect to host
 constructive.men: could not connect to host
-consultorcr.net: could not connect to host
 continuation.io: could not connect to host
 corecdn.org: could not connect to host
 corinnanese.de: could not connect to host
@@ -591,7 +599,6 @@ criticalaim.com: could not connect to host
 crl-autos.com: could not connect to host
 crow.tw: could not connect to host
 crox.co: could not connect to host
-crypto-armory.com: could not connect to host
 cryptoisnotacrime.org: could not connect to host
 cryptoki.fr: could not connect to host
 cryptolosophy.io: could not connect to host
@@ -661,6 +668,7 @@ ddmeportal.com: could not connect to host
 de-servers.de: could not connect to host
 deadmann.com: could not connect to host
 deborahmarinelli.eu: could not connect to host
+decomplify.com: could not connect to host
 decorincasa.com.br: could not connect to host
 decormiernissanparts.com: could not connect to host
 decoyrouting.com: could not connect to host
@@ -675,6 +683,7 @@ derive.cc: could not connect to host
 dermacarecomplex.com: could not connect to host
 dermapuur.nl: could not connect to host
 designsbykerrialee.co.uk: could not connect to host
+desmaakvanplanten.be: could not connect to host
 detalhecomercio.com.br: could not connect to host
 detecte-fuite.ch: could not connect to host
 detecte.ch: could not connect to host
@@ -751,6 +760,7 @@ draghive.net: could not connect to host
 dragonwork.me: could not connect to host
 drakfot.se: could not connect to host
 dreamaholic.club: could not connect to host
+dreamhack.com: could not connect to host
 dreaming.solutions: could not connect to host
 dreizwosechs.de: could not connect to host
 driving-lessons.co.uk: could not connect to host
@@ -796,6 +806,7 @@ einsteinathome.org: could not connect to host
 ejgconsultancy.co.uk: could not connect to host
 ekobudisantoso.net: could not connect to host
 ekong366.com: could not connect to host
+elarvee.xyz: could not connect to host
 electricalcontrolpanels.co.uk: could not connect to host
 electricianumhlangarocks.co.za: could not connect to host
 electronicafacil.net: could not connect to host
@@ -803,7 +814,9 @@ elektronring.com: could not connect to host
 elenorsmadness.org: could not connect to host
 eletesstilus.hu: could not connect to host
 elevateandprosper.com: could not connect to host
+elia.cloud: could not connect to host
 elonbase.com: could not connect to host
+eloxt.com: could not connect to host
 elsword.moe: could not connect to host
 eltransportquevolem.org: could not connect to host
 elytronsecurity.com: could not connect to host
@@ -823,6 +836,7 @@ enpalmademallorca.info: could not connect to host
 enskat.de: could not connect to host
 enskatson-sippe.de: could not connect to host
 entaurus.com: could not connect to host
+entrainr.com: could not connect to host
 envelope.co.nz: could not connect to host
 eolme.ml: could not connect to host
 er-music.com: could not connect to host
@@ -840,6 +854,7 @@ esseriumani.com: could not connect to host
 essplusmed.org: could not connect to host
 etenendrinken.nu: could not connect to host
 ethanfaust.com: could not connect to host
+ethiobaba.com: could not connect to host
 etzi.myds.me: could not connect to host
 euexia.fr: could not connect to host
 eung.ga: could not connect to host
@@ -855,6 +870,7 @@ evrial.com: could not connect to host
 eworksmedia.com: could not connect to host
 exceptionalservices.us: could not connect to host
 exo.do: could not connect to host
+expressemotion.net: could not connect to host
 exteriorservices.io: could not connect to host
 extratorrent.fyi: could not connect to host
 extratorrent.red: could not connect to host
@@ -875,6 +891,7 @@ fafatiger.com: could not connect to host
 faithwatch.org: could not connect to host
 falkus.net: could not connect to host
 fallenangeldrinks.eu: could not connect to host
+fam-stemmer.de: could not connect to host
 famer.me: could not connect to host
 fameuxhosting.co.uk: could not connect to host
 familie-leu.ch: could not connect to host
@@ -927,6 +944,7 @@ flyingdoggy.net: could not connect to host
 fmovies.life: could not connect to host
 focalforest.com: could not connect to host
 fognini-depablo.eu: could not connect to host
+foodev.de: could not connect to host
 forcamp.ga: could not connect to host
 foreverssl.com: could not connect to host
 forsyththeatre.com: could not connect to host
@@ -954,12 +972,12 @@ freshcode.nl: could not connect to host
 frickelboxx.de: could not connect to host
 frickenate.com: could not connect to host
 friedhelm-wolf.de: could not connect to host
-friller.com.au: could not connect to host
 frodriguez.xyz: could not connect to host
 frolov.net: could not connect to host
 fromix.de: could not connect to host
 fromlemaytoz.com: could not connect to host
 frosty-gaming.xyz: could not connect to host
+frowin-stemmer.de: could not connect to host
 frp-roleplay.de: could not connect to host
 fsfi.is: could not connect to host
 ftgho.com: could not connect to host
@@ -985,6 +1003,7 @@ g1jeu.com: could not connect to host
 gabriele-kluge.de: could not connect to host
 gafachi.com: could not connect to host
 gagor.pl: could not connect to host
+gaiserik.com: could not connect to host
 galgoafegao.com.br: could not connect to host
 galgoingles.com.br: could not connect to host
 gam3rs.de: could not connect to host
@@ -996,6 +1015,7 @@ gamhealth.net: could not connect to host
 garage-door.pro: could not connect to host
 gasbarkenora.com: could not connect to host
 gasnews.net: could not connect to host
+gatapro.net: could not connect to host
 gautham.pro: could not connect to host
 gay-jays.com: could not connect to host
 gaygeeks.de: could not connect to host
@@ -1026,6 +1046,7 @@ getgeek.io: could not connect to host
 getgeek.no: could not connect to host
 getgeek.nu: could not connect to host
 getgeek.pl: could not connect to host
+geto.ml: could not connect to host
 getyourphix.tk: could not connect to host
 gevaulug.fr: could not connect to host
 gfoss.gr: could not connect to host
@@ -1070,6 +1091,7 @@ greuel.online: could not connect to host
 gritte.net: could not connect to host
 grossmisconduct.news: could not connect to host
 growingmetrics.com: could not connect to host
+grunwaldzki.center: could not connect to host
 grusig-geil.ch: could not connect to host
 gsmkungen.com: could not connect to host
 guelphhydropool.com: could not connect to host
@@ -1078,9 +1100,7 @@ guildgearscore.cf: could not connect to host
 guinea-pig.co: could not connect to host
 gunhunter.com: could not connect to host
 gus.moe: could not connect to host
-guts.me: could not connect to host
 gvchannel.xyz: could not connect to host
-gwrtech.com: could not connect to host
 gxgx.org: could not connect to host
 gzitech.net: could not connect to host
 gzpblog.com: could not connect to host
@@ -1098,13 +1118,13 @@ half-logic.eu.org: could not connect to host
 halta.info: could not connect to host
 hamking.tk: could not connect to host
 hamu.blue: could not connect to host
+hang333.pw: could not connect to host
 hanksservice.com: could not connect to host
 hansen.hn: could not connect to host
 happytiger.eu: could not connect to host
 hapsfordmill.co.uk: could not connect to host
 hapvm.com: could not connect to host
 hardergayporn.com: could not connect to host
-harringtonca.com: could not connect to host
 harrypottereditor.net: could not connect to host
 has-no-email-set.de: could not connect to host
 hasabig.wang: could not connect to host
@@ -1165,6 +1185,7 @@ homesfordinner.ca: could not connect to host
 homewatt.co.uk: could not connect to host
 homoglyph.net: could not connect to host
 honeytracks.com: could not connect to host
+honkhonk.net: could not connect to host
 hoodoo.io: could not connect to host
 hoodoo.tech: could not connect to host
 hopglass.eu: could not connect to host
@@ -1187,6 +1208,7 @@ hudingyuan.cn: could not connect to host
 huiser.nl: could not connect to host
 hukaloh.com: could not connect to host
 hukkatavara.com: could not connect to host
+hundter.com: could not connect to host
 hunger.im: could not connect to host
 huongquynh.com: could not connect to host
 huwjones.me: could not connect to host
@@ -1201,6 +1223,7 @@ i4m1k0su.com: could not connect to host
 i95.me: could not connect to host
 iadttaveras.com: could not connect to host
 iamsoareyou.se: could not connect to host
+iba.community: could not connect to host
 ibox.ovh: could not connect to host
 ibron.co: could not connect to host
 ibsafrica.co.za: could not connect to host
@@ -1223,6 +1246,7 @@ ifcfg.me: could not connect to host
 ifxnet.com: could not connect to host
 igamingforums.com: could not connect to host
 ihatethissh.it: could not connect to host
+ihc.im: could not connect to host
 iideaz.org: could not connect to host
 ikenmeyer.com: could not connect to host
 ikenmeyer.eu: could not connect to host
@@ -1240,9 +1264,11 @@ imlinan.info: could not connect to host
 imlinan.net: could not connect to host
 immersionwealth.com: could not connect to host
 immobilien-wallat.de: could not connect to host
+imoe.ac.cn: could not connect to host
 imoner.ga: could not connect to host
 imperdintechnologies.com: could not connect to host
 impulse-clan.de: could not connect to host
+imydl.tech: could not connect to host
 increasetestosteronelevels.org: could not connect to host
 industreiler.com: could not connect to host
 industreiler.com.br: could not connect to host
@@ -1273,6 +1299,8 @@ invenio.software: could not connect to host
 inventum.cloud: could not connect to host
 investingdiary.cn: could not connect to host
 investingtrader.net: could not connect to host
+investorloanshub.com: could not connect to host
+invitescene.com: could not connect to host
 invkao.com: could not connect to host
 iodu.re: could not connect to host
 ionc.ca: could not connect to host
@@ -1296,6 +1324,7 @@ itpro-mg.de: could not connect to host
 its-schindler.de: could not connect to host
 its-v.de: could not connect to host
 itsatrap.nl: could not connect to host
+itsaw.de: could not connect to host
 ivanilla.org: could not connect to host
 ivanpolchenko.com: could not connect to host
 ivfmeds.com: could not connect to host
@@ -1304,7 +1333,6 @@ iwex.swiss: could not connect to host
 iwos.io: could not connect to host
 j0ng.xyz: could not connect to host
 jaaxypro.com: could not connect to host
-jaccblog.com: could not connect to host
 jackyyf.com: could not connect to host
 jaimechanaga.com: could not connect to host
 jaion.ml: could not connect to host
@@ -1334,7 +1362,6 @@ jerrypau.ca: could not connect to host
 jhburton.co.uk: could not connect to host
 jhermsmeier.de: could not connect to host
 jiaqiang.vip: could not connect to host
-jichi.io: could not connect to host
 jmb.lc: could not connect to host
 jobmedic.com: could not connect to host
 joecod.es: could not connect to host
@@ -1344,7 +1371,6 @@ johntomasowa.com: could not connect to host
 jonathanmassacand.ch: could not connect to host
 jonathansanchez.pro: could not connect to host
 jonfor.net: could not connect to host
-jooto.com: could not connect to host
 jpod.cc: could not connect to host
 jsjyhzy.cc: could not connect to host
 juliaoantiguidades.com.br: could not connect to host
@@ -1368,11 +1394,9 @@ kaloix.de: could not connect to host
 kamalame.co: could not connect to host
 kamitech.ch: could not connect to host
 kancolle.me: could not connect to host
-kandalife.com: could not connect to host
 kanganer.com: could not connect to host
 kangzaber.com: could not connect to host
 kapo.info: could not connect to host
-kapseli.net: could not connect to host
 karuneshjohri.com: could not connect to host
 kat.al: could not connect to host
 kati0.com: could not connect to host
@@ -1381,6 +1405,7 @@ kawaiiku.de: could not connect to host
 kaydan.io: could not connect to host
 kayipmurekkep.com: could not connect to host
 kearney.io: could not connect to host
+keithws.net: could not connect to host
 kellyandantony.com: could not connect to host
 kelm.me: could not connect to host
 kennynet.co.uk: could not connect to host
@@ -1398,7 +1423,6 @@ kidbacker.com: could not connect to host
 kieranweightman.me: could not connect to host
 kievradio.com: could not connect to host
 kikuzuki.org: could not connect to host
-killerrobots.com: could not connect to host
 kinderjugendfreizeitverein.de: could not connect to host
 kinepolis-studio.ga: could not connect to host
 kineto.space: could not connect to host
@@ -1431,14 +1455,15 @@ korni22.org: could not connect to host
 kotitesti.fi: could not connect to host
 kotorimusic.ga: could not connect to host
 kottur.is: could not connect to host
-kouten-jp.com: could not connect to host
 kozmik.co: could not connect to host
 kpvpn.com: could not connect to host
 krampus-fischamend.at: could not connect to host
 kriegskindernothilfe.de: could not connect to host
+kriptosec.com: could not connect to host
 ktube.yt: could not connect to host
 kubusadvocaten.nl: could not connect to host
 kuko-crews.org: could not connect to host
+kuroinu.jp: could not connect to host
 kuwago.io: could not connect to host
 kwikmed.eu: could not connect to host
 kwipi.com: could not connect to host
@@ -1458,14 +1483,12 @@ lacasseroy.com: could not connect to host
 ladylikeit.com: could not connect to host
 laforetenchantee.ch: could not connect to host
 lafr4nc3.xyz: could not connect to host
-lakehavasucityhomebuyerscredit.com: could not connect to host
 lakehavasuhomebuyercredit.com: could not connect to host
 lakehavasuhouserentals.com: could not connect to host
 landell.ml: could not connect to host
 langendorf-ernaehrung-training.de: could not connect to host
 lannainnovation.com: could not connect to host
 lanonfire.com: could not connect to host
-lantian.pub: could not connect to host
 laozhu.me: could not connect to host
 larondinedisinfestazione.com: could not connect to host
 latamarissiere.eu: could not connect to host
@@ -1493,7 +1516,9 @@ leelou.wedding: could not connect to host
 leerkotte.eu: could not connect to host
 legal.farm: could not connect to host
 legaltip.eu: could not connect to host
+legoutdesplantes.be: could not connect to host
 leonardcamacho.me: could not connect to host
+leonhooijer.nl: could not connect to host
 lerlivros.online: could not connect to host
 lescomptoirsdepierrot.com: could not connect to host
 lesdouceursdeliyana.com: could not connect to host
@@ -1510,10 +1535,8 @@ lhsj68.com: could not connect to host
 lhsj78.com: could not connect to host
 liaozheqi.cn: could not connect to host
 libertas-tech.com: could not connect to host
-librebox.de: could not connect to host
 libscode.com: could not connect to host
 liceserv.com: could not connect to host
-lidong.me: could not connect to host
 lied8.eu: could not connect to host
 lifeinsurances.pro: could not connect to host
 lifeinsurances24.com: could not connect to host
@@ -1537,7 +1560,9 @@ litcomphonors.com: could not connect to host
 littlelundgrenladies.com: could not connect to host
 liukang.tech: could not connect to host
 llvm.us: could not connect to host
+lmddgtfy.net: could not connect to host
 lmrcouncil.gov: could not connect to host
+lmsptfy.com: could not connect to host
 loanstreet.be: could not connect to host
 lobosdomain.ddns.net: could not connect to host
 lobosdomain.no-ip.info: could not connect to host
@@ -1565,6 +1590,7 @@ lucasgaland.com: could not connect to host
 lucassoler.com.ar: could not connect to host
 lucidlogs.com: could not connect to host
 luganskservers.net: could not connect to host
+lui.pink: could not connect to host
 luk.photo: could not connect to host
 lukasunger.cz: could not connect to host
 lukasunger.net: could not connect to host
@@ -1580,7 +1606,6 @@ maartenterpstra.xyz: could not connect to host
 madeintucson.org: could not connect to host
 mader.jp: could not connect to host
 madnetwork.org: could not connect to host
-magicball.co: could not connect to host
 magnacumlaude.co: could not connect to host
 maik-mahlow.de: could not connect to host
 mail4geek.com: could not connect to host
@@ -1608,6 +1633,7 @@ marketingdesignu.cz: could not connect to host
 markllego.com: could not connect to host
 marko-fenster24.de: could not connect to host
 markrego.com: could not connect to host
+marmotte.love: could not connect to host
 martin-mattel.com: could not connect to host
 martins.im: could not connect to host
 marxist.party: could not connect to host
@@ -1723,7 +1749,6 @@ moeyi.xyz: could not connect to host
 mongla168.net: could not connect to host
 mongla88.net: could not connect to host
 monitori.ng: could not connect to host
-montas.io: could not connect to host
 mooselook.de: could not connect to host
 moparcraft.com: could not connect to host
 moparcraft.org: could not connect to host
@@ -1732,6 +1757,7 @@ morfitronik.pl: could not connect to host
 morganino.eu: could not connect to host
 morz.org: could not connect to host
 mosaique-lachenaie.fr: could not connect to host
+mosfet.cz: could not connect to host
 moskva.guide: could not connect to host
 motherboard.services: could not connect to host
 motomorgen.com: could not connect to host
@@ -1754,7 +1780,6 @@ msz-fotografie.de: could not connect to host
 mtd.ovh: could not connect to host
 mtirc.co: could not connect to host
 mtn.cc: could not connect to host
-muchohentai.com: could not connect to host
 muga.space: could not connect to host
 muj-svet.cz: could not connect to host
 multivpn.cn.com: could not connect to host
@@ -1833,6 +1858,7 @@ next-taxi.ru: could not connect to host
 nexusbyte.de: could not connect to host
 nexusconnectinternational.eu: could not connect to host
 nexuscorporation.in: could not connect to host
+nfluence.org: could not connect to host
 ngiemboon.net: could not connect to host
 nginxyii.tk: could not connect to host
 ngocuong.net: could not connect to host
@@ -1842,7 +1868,7 @@ niklas.pw: could not connect to host
 nikobradshaw.com: could not connect to host
 nikolasbradshaw.com: could not connect to host
 nimidam.com: could not connect to host
-ninreiei.jp: could not connect to host
+ninofink.com: could not connect to host
 niouininon.eu: could not connect to host
 nirada.info: could not connect to host
 nishikino-maki.com: could not connect to host
@@ -1864,6 +1890,7 @@ notevencode.com: could not connect to host
 novascan.net: could not connect to host
 novfishing.ru: could not connect to host
 novgorod-avia.ru: could not connect to host
+nowremindme.com: could not connect to host
 nsa.wtf: could not connect to host
 nsbfalconacademy.org: could not connect to host
 nsdev.cn: could not connect to host
@@ -1909,9 +1936,7 @@ openclub24.ru: could not connect to host
 openconnect.com.au: could not connect to host
 opinion8td.com: could not connect to host
 orangekey.tk: could not connect to host
-oranges.tokyo: could not connect to host
 oricejoc.com: could not connect to host
-orro.ro: could not connect to host
 oscarmashauri.com: could not connect to host
 oscillation-services.fr: could not connect to host
 oscsdp.cz: could not connect to host
@@ -1945,7 +1970,6 @@ patrickneuro.de: could not connect to host
 paulshir.com: could not connect to host
 paulshir.is: could not connect to host
 paveljanda.com: [Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsISiteSecurityService.processHeader]"  nsresult: "0x80004005 (NS_ERROR_FAILURE)"  location: "JS frame :: /builds/slave/m-cen-l64-periodicupdate-00000/getHSTSPreloadList.js :: processStsHeader :: line 116"  data: no]
-pavelstriz.cz: could not connect to host
 pay.ubuntu.com: could not connect to host
 paymon.tj: could not connect to host
 paypod.org: could not connect to host
@@ -1955,6 +1979,7 @@ pbytes.com: could not connect to host
 pcvirusclear.com: could not connect to host
 pear2pear.de: could not connect to host
 peerless.ae: could not connect to host
+peervpn.net: could not connect to host
 peirong.me: could not connect to host
 pemagrid.org: could not connect to host
 pengisatelier.net: could not connect to host
@@ -1968,6 +1993,7 @@ pfolta.net: could not connect to host
 pgmann.cf: could not connect to host
 pgmsource.com: could not connect to host
 pharmaboard.org: could not connect to host
+phcimages.com: could not connect to host
 phdwuda.com: could not connect to host
 philippa.cool: could not connect to host
 phillippi.me: could not connect to host
@@ -1999,7 +2025,6 @@ playsource.co: could not connect to host
 please-deny.me: could not connect to host
 pleaseuseansnisupportedbrowser.ml: could not connect to host
 plussizereviews.com: could not connect to host
-pmbremer.de: could not connect to host
 pmessage.ch: could not connect to host
 pmklaassen.com: could not connect to host
 pogs.us: could not connect to host
@@ -2040,7 +2065,6 @@ prism-communication.com: could not connect to host
 privacyforjournalists.org.au: could not connect to host
 privacymanatee.com: could not connect to host
 privcloud.org: could not connect to host
-priverify.com: could not connect to host
 privilegevisa.fr: could not connect to host
 proactive.run: could not connect to host
 professional.cleaning: could not connect to host
@@ -2098,7 +2122,6 @@ quietus.gq: could not connect to host
 qybot.cc: could not connect to host
 r-cut.fr: could not connect to host
 r0t.co: could not connect to host
-r40.us: could not connect to host
 racasdecachorro.org: could not connect to host
 rackblue.com: could not connect to host
 radioafibra.com.br: could not connect to host
@@ -2182,6 +2205,7 @@ roolevoi.ru: could not connect to host
 room2d.com: could not connect to host
 rootbsd.at: could not connect to host
 rospa100.com: could not connect to host
+rosslug.org.uk: could not connect to host
 rostov-avia.ru: could not connect to host
 rotterdamjazz.info: could not connect to host
 royzez.com: could not connect to host
@@ -2190,6 +2214,7 @@ rozalynne-dawn.ga: could not connect to host
 rpasafrica.com: could not connect to host
 rro.rs: could not connect to host
 rs-devdemo.host: could not connect to host
+rsldb.com: could not connect to host
 rtc.fun: could not connect to host
 ruanmi.de: could not connect to host
 rubbix.net: could not connect to host
@@ -2200,6 +2225,7 @@ rukhaiyar.com: could not connect to host
 run-forrest.run: could not connect to host
 runcarina.com: could not connect to host
 rundumcolumn.xyz: could not connect to host
+rushball.net: could not connect to host
 rustbyexample.com: could not connect to host
 ruurdboomsma.nl: could not connect to host
 s0923.com: could not connect to host
@@ -2258,6 +2284,7 @@ seankilgarriff.com: could not connect to host
 searx.pw: could not connect to host
 sebi.cf: could not connect to host
 secitem.de: could not connect to host
+secpatrol.de: could not connect to host
 sectest.ml: could not connect to host
 secure-automotive-cloud.com: could not connect to host
 secure-automotive-cloud.org: could not connect to host
@@ -2280,6 +2307,7 @@ sellmoretires.com: could not connect to host
 sementes.gratis: could not connect to host
 seomen.biz: could not connect to host
 seoscribe.net: could not connect to host
+seproco.com: could not connect to host
 servecrypt.com: could not connect to host
 servecrypt.ru: could not connect to host
 server.pk: could not connect to host
@@ -2323,6 +2351,7 @@ signosquecombinam.com.br: could not connect to host
 sijmenschoon.nl: could not connect to host
 sikatehtaat.fi: could not connect to host
 siku.pro: could not connect to host
+siloportem.net: could not connect to host
 silqueskineyeserum.com: could not connect to host
 silverback.is: could not connect to host
 silvistefi.com: could not connect to host
@@ -2335,7 +2364,6 @@ sims4hub.ga: could not connect to host
 sinfulforums.net: could not connect to host
 siqi.wang: could not connect to host
 sitemaxiphilippe.ch: could not connect to host
-sivyerge.com: could not connect to host
 skarox.ru: could not connect to host
 sketchmyroom.com: could not connect to host
 skoda-im-dialog.de: could not connect to host
@@ -2377,6 +2405,7 @@ sorenam.com: could not connect to host
 sortaweird.net: could not connect to host
 sosteam.jp: could not connect to host
 sotiran.com: could not connect to host
+soulema.com: could not connect to host
 sourcecode.love: could not connect to host
 sowncloud.de: could not connect to host
 sp.rw: could not connect to host
@@ -2386,13 +2415,14 @@ sparkbase.cn: could not connect to host
 sparkwood.org: could not connect to host
 spartantheatre.org: could not connect to host
 spawn.cz: could not connect to host
+sperohub.lt: could not connect to host
 sphinx.network: could not connect to host
 spicydog.tk: could not connect to host
 spicywombat.com: could not connect to host
 spitfireuav.com: could not connect to host
 split.is: could not connect to host
 springsoffthegrid.com: could not connect to host
-sql-und-xml.de: could not connect to host
+spron.in: could not connect to host
 squids.space: could not connect to host
 squirtlesbians.net: could not connect to host
 sqzryang.com: could not connect to host
@@ -2530,17 +2560,18 @@ thebuffalotavern.com: could not connect to host
 thedailyupvote.com: could not connect to host
 theeducationchannel.info: could not connect to host
 theepankar.com: could not connect to host
+theevergreen.me: could not connect to host
 thefox.co: could not connect to host
 thefrk.xyz: could not connect to host
 thelinuxspace.com: could not connect to host
 thelostyankee.com: could not connect to host
 thenrdhrd.nl: could not connect to host
+theosophie-afrique.org: could not connect to host
 theoverfly.co: could not connect to host
 theposhfudgecompany.co.uk: could not connect to host
 theprincegame.com: could not connect to host
 theprivacysolution.com: could not connect to host
 thequillmagazine.org: could not connect to host
-therevenge.me: could not connect to host
 thermique.ch: could not connect to host
 thesehighsandlows.com: could not connect to host
 thesled.net: could not connect to host
@@ -2583,6 +2614,7 @@ topdetoxcleanse.com: could not connect to host
 topnotchendings.com: could not connect to host
 tor2web.org: could not connect to host
 toretfaction.net: could not connect to host
+torproject.ovh: could not connect to host
 torstensenf.de: could not connect to host
 totallynotaserver.com: could not connect to host
 totch.de: could not connect to host
@@ -2632,6 +2664,7 @@ tutoragency.org: could not connect to host
 tutorio.ga: could not connect to host
 tuvangoicuoc.com: could not connect to host
 tuxhound.org: could not connect to host
+twaka.com: could not connect to host
 twinkieman.com: could not connect to host
 twinkseason.com: could not connect to host
 twiri.net: could not connect to host
@@ -2640,12 +2673,10 @@ twitter.ax: could not connect to host
 twotube.ie: could not connect to host
 twuni.org: could not connect to host
 tykoon.com: could not connect to host
-tyler.rs: could not connect to host
 tylerharcourt.ca: could not connect to host
 tylerharcourt.com: could not connect to host
 tylerharcourt.net: could not connect to host
 tylerharcourt.org: could not connect to host
-tyleromeara.com: could not connect to host
 tysye.ca: could not connect to host
 tzwe.com: could not connect to host
 ubalert.com: could not connect to host
@@ -2675,6 +2706,7 @@ uwimonacs.org.jm: could not connect to host
 uygindir.ml: could not connect to host
 vaaddress.co: could not connect to host
 vacationfund.co: could not connect to host
+vadennissanofhinesvilleparts.com: could not connect to host
 vadik.me: could not connect to host
 valecnatechnika.cz: could not connect to host
 valenhub.com: could not connect to host
@@ -2706,7 +2738,6 @@ vgatest.nl: could not connect to host
 vicenage.com: could not connect to host
 viciousviscosity.xyz: could not connect to host
 videorullen.se: could not connect to host
-viepixel.at: could not connect to host
 vikasbabyworld.de: could not connect to host
 viladochurrasco.com.br: could not connect to host
 villainsclothing.com.au: could not connect to host
@@ -2716,7 +2747,6 @@ vinesauce.info: could not connect to host
 vinetalk.net: could not connect to host
 vipnettikasinoklubi.com: could not connect to host
 visiongamestudios.com: could not connect to host
-visionless.me: could not connect to host
 visionthroughknowledge.com: could not connect to host
 visiontree-beta.eu: could not connect to host
 visiontree.eu: could not connect to host
@@ -2780,6 +2810,7 @@ webtar.info: could not connect to host
 webtech.com.br: could not connect to host
 webthings.com.br: could not connect to host
 webtobesocial.de: could not connect to host
+wecanvisit.com: could not connect to host
 week.report: could not connect to host
 weideheuvel.org: could not connect to host
 weiler.xyz: could not connect to host
@@ -2839,6 +2870,7 @@ wp-fastsearch.de: could not connect to host
 wp-stack.pro: could not connect to host
 wp6.pw: could not connect to host
 wprevs.com: could not connect to host
+wrara.org: could not connect to host
 wriedts.de: could not connect to host
 wsb-immo.at: could not connect to host
 wsdcap.com: could not connect to host
@@ -2889,12 +2921,14 @@ xn--ykrp42k.com: could not connect to host
 xombra.com: could not connect to host
 xpwn.cz: could not connect to host
 xtzone.be: could not connect to host
+xujan.com: could not connect to host
 xuntaosms.com: could not connect to host
 xwaretech.info: could not connect to host
 y3451.com: could not connect to host
 yabrt.cn: could not connect to host
 yafuoku.ru: could not connect to host
 yahoo.ax: could not connect to host
+yanovich.net: could not connect to host
 yarchives.jp: could not connect to host
 yaucy.win: could not connect to host
 yawen.tw: could not connect to host
@@ -2934,7 +2968,6 @@ z0rro.net: could not connect to host
 zachbolinger.com: could not connect to host
 zaem.tv: could not connect to host
 zalan.do: could not connect to host
-zalohovaniburian.cz: could not connect to host
 zaoext.com: could not connect to host
 zbchen.com: could not connect to host
 zby.io: could not connect to host
@@ -2945,6 +2978,7 @@ zero-sum.xyz: could not connect to host
 zero-x-baadf00d.com: could not connect to host
 zerocool.io: could not connect to host
 zerosource.net: could not connect to host
+zewtie.com: could not connect to host
 zhangfangzhou.com: could not connect to host
 zhangsir.net: could not connect to host
 zhaochen.xyz: could not connect to host
@@ -2958,7 +2992,6 @@ zobraz.cz: could not connect to host
 zohar.shop: could not connect to host
 zokster.net: could not connect to host
 zoological-gardens.eu: could not connect to host
-zoomseoservices.com: could not connect to host
 zudomc.me: could not connect to host
 zuehlcke.de: could not connect to host
 zukix.com: could not connect to host
@@ -2974,7 +3007,7 @@ zzw.ca: could not connect to host
 007sascha.de: did not receive HSTS header
 016298.com: did not receive HSTS header
 020wifi.nl: [Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsISiteSecurityService.processHeader]"  nsresult: "0x80004005 (NS_ERROR_FAILURE)"  location: "JS frame :: /builds/slave/m-cen-l64-periodicupdate-00000/getHSTSPreloadList.js :: processStsHeader :: line 116"  data: no]
-0222aa.com: could not connect to host
+0222aa.com: did not receive HSTS header
 023838.com: did not receive HSTS header
 02dl.net: did not receive HSTS header
 040fit.nl: did not receive HSTS header
@@ -3025,7 +3058,7 @@ zzw.ca: could not connect to host
 16packets.com: could not connect to host
 173vpn.cn: could not connect to host
 173vpns.com: did not receive HSTS header
-173vpnv.com: did not receive HSTS header
+173vpnv.com: could not connect to host
 188betwarriors.co.uk: could not connect to host
 188trafalgar.ca: did not receive HSTS header
 189dv.com: did not receive HSTS header
@@ -3061,7 +3094,7 @@ zzw.ca: could not connect to host
 2intermediate.co.uk: did not receive HSTS header
 2or3.tk: could not connect to host
 2smart4food.com: did not receive HSTS header
-2ss.jp: could not connect to host
+2ss.jp: did not receive HSTS header
 300651.ru: did not receive HSTS header
 300mbmovie24.com: could not connect to host
 300mbmovies4u.cc: could not connect to host
@@ -3121,7 +3154,7 @@ zzw.ca: could not connect to host
 60ych.net: did not receive HSTS header
 6120.eu: did not receive HSTS header
 64616e.xyz: could not connect to host
-660011.com: max-age too low: 0
+660011.com: could not connect to host
 69square.com: could not connect to host
 721av.com: max-age too low: 2592000
 7777av.co: could not connect to host
@@ -3164,7 +3197,7 @@ a9c.co: could not connect to host
 aa7733.com: could not connect to host
 aaeblog.com: did not receive HSTS header
 aaeblog.net: did not receive HSTS header
-aaeblog.org: could not connect to host
+aaeblog.org: did not receive HSTS header
 aanbieders.ga: did not receive HSTS header
 aaoo.net: could not connect to host
 aapp.space: could not connect to host
@@ -3252,6 +3285,7 @@ adoal.net: did not receive HSTS header
 adoge.me: could not connect to host
 adonairelogios.com.br: could not connect to host
 adopteunsiteflash.com: could not connect to host
+adprospb.com: did not receive HSTS header
 adquisitio.de: could not connect to host
 adquisitio.in: could not connect to host
 adriancohea.ninja: did not receive HSTS header
@@ -3360,7 +3394,6 @@ alexperry.io: could not connect to host
 alexyang.me: did not receive HSTS header
 alfa24.pro: could not connect to host
 alfredxing.com: did not receive HSTS header
-alicestudio.it: did not receive HSTS header
 alistairpialek.com: max-age too low: 86400
 alittlebitcheeky.com: did not receive HSTS header
 aljmz.com: could not connect to host
@@ -3376,7 +3409,6 @@ allgrass.es: did not receive HSTS header
 allgrass.net: did not receive HSTS header
 alliance-compacts.com: did not receive HSTS header
 allinnote.com: could not connect to host
-allkindzabeats.com: did not receive HSTS header
 allmbw.com: could not connect to host
 allmystery.de: did not receive HSTS header
 allo-symo.fr: did not receive HSTS header
@@ -3404,7 +3436,6 @@ altamarea.se: could not connect to host
 alteqnia.com: could not connect to host
 altfire.ca: could not connect to host
 altmv.com: max-age too low: 7776000
-altoneum.com: could not connect to host
 aluminium-scaffolding.co.uk: could not connect to host
 alunjam.es: did not receive HSTS header
 alusta.co: could not connect to host
@@ -3420,6 +3451,7 @@ amerhd.com: could not connect to host
 american-truck-simulator.de: could not connect to host
 american-truck-simulator.net: could not connect to host
 americanbio.com: did not receive HSTS header
+americanoutlawjeepparts.com: did not receive HSTS header
 americansforcommunitydevelopment.org: did not receive HSTS header
 americansportsinstitute.org: did not receive HSTS header
 americanworkwear.nl: did not receive HSTS header
@@ -3458,6 +3490,7 @@ andrerose.ca: did not receive HSTS header
 andrew.fi: did not receive HSTS header
 andrew.london: did not receive HSTS header
 andrewbroekman.com: did not receive HSTS header
+andrewhowden.com: did not receive HSTS header
 andrewmichaud.beer: could not connect to host
 andrewregan.me: could not connect to host
 andrewvoce.com: did not receive HSTS header
@@ -3465,7 +3498,7 @@ andrewyg.net: could not connect to host
 andreypopp.com: could not connect to host
 androidprosmart.com: could not connect to host
 androled.fr: max-age too low: 5184000
-andronika.net: did not receive HSTS header
+andronika.net: could not connect to host
 androoz.se: could not connect to host
 andyclark.io: could not connect to host
 andycraftz.eu: did not receive HSTS header
@@ -3627,7 +3660,7 @@ arvamus.eu: could not connect to host
 arzaroth.com: did not receive HSTS header
 as.se: could not connect to host
 as9178.net: could not connect to host
-asadzulfahri.com: did not receive HSTS header
+asadzulfahri.com: could not connect to host
 asahikoji.net: could not connect to host
 asasuou.pw: could not connect to host
 asc16.com: could not connect to host
@@ -3769,6 +3802,7 @@ babyliss-pro.net: did not receive HSTS header
 babymasaze.cz: did not receive HSTS header
 babysaying.me: could not connect to host
 bacchanallia.com: could not connect to host
+bacimg.com: did not receive HSTS header
 back-bone.nl: did not receive HSTS header
 backenmachtgluecklich.de: max-age too low: 2592000
 backgroundchecks.online: did not receive HSTS header
@@ -3833,7 +3867,6 @@ baud.ninja: could not connect to host
 baudairenergyservices.com: did not receive HSTS header
 baum.ga: could not connect to host
 baumstark.ca: could not connect to host
-baychimo.com: did not receive HSTS header
 bayinstruments.com: could not connect to host
 baysse.eu: could not connect to host
 bazarstupava.sk: could not connect to host
@@ -3999,7 +4032,6 @@ birgitandmerlin.com: did not receive HSTS header
 birkman.com: could not connect to host
 bismarck.moe: did not receive HSTS header
 bisterfeldt.com: could not connect to host
-bistrocean.com: did not receive HSTS header
 bitbit.org: did not receive HSTS header
 bitbr.net: did not receive HSTS header
 bitcantor.com: did not receive HSTS header
@@ -4117,6 +4149,7 @@ bohan.life: could not connect to host
 boiadeirodeberna.com: could not connect to host
 bokeyy.com: could not connect to host
 boltdata.io: could not connect to host
+boltn.uk: did not receive HSTS header
 bolwerk.com.br: did not receive HSTS header
 bonapp.restaurant: could not connect to host
 boneko.de: could not connect to host
@@ -4326,6 +4359,7 @@ c2lab.net: did not receive HSTS header
 c3-compose.com: could not connect to host
 c3b.info: could not connect to host
 c3ie.com: did not receive HSTS header
+c4.hk: did not receive HSTS header
 cabsites.com: could not connect to host
 cabusar.fr: did not receive HSTS header
 caconnect.org: could not connect to host
@@ -4389,6 +4423,7 @@ carlo.mx: did not receive HSTS header
 carlolly.co.uk: could not connect to host
 carlosalves.info: could not connect to host
 carlsbouncycastlesandhottubs.co.uk: did not receive HSTS header
+carlscatering.com: did not receive HSTS header
 carpliyz.com: did not receive HSTS header
 carroarmato0.be: did not receive HSTS header
 carsforbackpackers.com: could not connect to host
@@ -4494,6 +4529,7 @@ chaska.co.za: did not receive HSTS header
 chat-porc.eu: did not receive HSTS header
 chatbot.me: did not receive HSTS header
 chateauconstellation.ch: did not receive HSTS header
+chatint.com: did not receive HSTS header
 chatup.cf: could not connect to host
 chaulootz.com: did not receive HSTS header
 chcemvediet.sk: max-age too low: 1555200
@@ -4747,6 +4783,7 @@ consciousbrands.net.au: could not connect to host
 consejosdehogar.com: did not receive HSTS header
 console.python.org: did not receive HSTS header
 console.support: did not receive HSTS header
+consultorcr.net: did not receive HSTS header
 consumer.gov: did not receive HSTS header
 consumidor.gov: did not receive HSTS header
 contactbig.com: did not receive HSTS header
@@ -4917,7 +4954,7 @@ cuvva.insure: did not receive HSTS header
 cvjm-memmingen.de: did not receive HSTS header
 cvtparking.co.uk: did not receive HSTS header
 cwage.com: could not connect to host
-cwrcoding.com: did not receive HSTS header
+cwrcoding.com: could not connect to host
 cyanogenmod.xxx: could not connect to host
 cyber-perikarp.eu: could not connect to host
 cybercecurity.com: did not receive HSTS header
@@ -5035,7 +5072,7 @@ dccraft.net: could not connect to host
 dctxf.com: did not receive HSTS header
 dcuofriends.net: could not connect to host
 dcurt.is: did not receive HSTS header
-dcw.io: did not receive HSTS header
+dcw.io: could not connect to host
 ddatsh.com: did not receive HSTS header
 ddocu.me: did not receive HSTS header
 deadsoul.net: max-age too low: 0
@@ -5133,11 +5170,12 @@ devopps.me: did not receive HSTS header
 devopsconnected.com: could not connect to host
 devtub.com: did not receive HSTS header
 devuan.org: did not receive HSTS header
+devyn.ca: did not receive HSTS header
 dewebwerf.nl: did not receive HSTS header
 dewin.io: could not connect to host
 dfrance.com.br: did not receive HSTS header
 dfviana.com.br: max-age too low: 2592000
-dhaynes.xyz: max-age too low: 2592000
+dhaynes.xyz: did not receive HSTS header
 dhpcs.com: did not receive HSTS header
 dhpiggott.net: did not receive HSTS header
 diablotine.rocks: could not connect to host
@@ -5225,7 +5263,6 @@ dmcibulldog.com: did not receive HSTS header
 dmdre.com: did not receive HSTS header
 dmix.ca: could not connect to host
 dmtry.me: did not receive HSTS header
-dmwall.cn: did not receive HSTS header
 dmz.ninja: could not connect to host
 dnsbird.net: could not connect to host
 dnscrypt.org: max-age too low: 0
@@ -5290,7 +5327,6 @@ dotbrick.co.th: did not receive HSTS header
 dotspaperie.com: could not connect to host
 doublethink.online: could not connect to host
 doubleyummy.uk: did not receive HSTS header
-douglasstafford.com: did not receive HSTS header
 dovecotadmin.org: could not connect to host
 doveholesband.co.uk: did not receive HSTS header
 dovetailnow.com: could not connect to host
@@ -5369,10 +5405,10 @@ dullsir.com: could not connect to host
 dunashoes.com: could not connect to host
 dune.io: could not connect to host
 dunea.nl: did not receive HSTS header
+dung-massage.fr: did not receive HSTS header
 duole30.com: could not connect to host
 duongpho.com: did not receive HSTS header
 duskopy.top: could not connect to host
-dutchessuganda.com: did not receive HSTS header
 dutchrank.com: did not receive HSTS header
 dutyfreeonboard.com: did not receive HSTS header
 duuu.ch: could not connect to host
@@ -5529,7 +5565,6 @@ elenoon.ir: did not receive HSTS header
 elgacien.de: could not connect to host
 elglobo.com.mx: max-age too low: 86400
 elguillatun.cl: did not receive HSTS header
-elhall.ru: did not receive HSTS header
 elimdengelen.com: did not receive HSTS header
 elitecovering.fr: did not receive HSTS header
 elitefishtank.com: could not connect to host
@@ -5618,6 +5653,7 @@ eqim.me: could not connect to host
 equate.net.au: did not receive HSTS header
 equatetechnologies.com.au: did not receive HSTS header
 equilibre-yoga-jennifer-will.com: could not connect to host
+equippers.de: did not receive HSTS header
 equitee.co: did not receive HSTS header
 equityflows.com: did not receive HSTS header
 erawanarifnugroho.com: did not receive HSTS header
@@ -5743,6 +5779,7 @@ expowerhps.com: did not receive HSTS header
 expressfinance.co.za: did not receive HSTS header
 extramoney.cash: did not receive HSTS header
 extrathemeshowcase.net: could not connect to host
+extratorrent.cool: did not receive HSTS header
 extratorrentlive.xyz: could not connect to host
 extratorrents.tech: could not connect to host
 extreemhost.nl: did not receive HSTS header
@@ -5833,6 +5870,7 @@ fbox.li: could not connect to host
 fdj.im: could not connect to host
 fdt.name: did not receive HSTS header
 feard.space: could not connect to host
+featuredmen.com: max-age too low: 0
 fedemo.top: did not receive HSTS header
 federalregister.gov: did not receive HSTS header
 fedo.moe: could not connect to host
@@ -5897,7 +5935,6 @@ finpt.com: did not receive HSTS header
 finsterlebnis.de: did not receive HSTS header
 fintechnics.com: did not receive HSTS header
 fiodental.com.br: did not receive HSTS header
-fioulmarket.fr: did not receive HSTS header
 firebaseio-demo.com: could not connect to host
 firebird.io: could not connect to host
 firefall.rocks: could not connect to host
@@ -6056,7 +6093,6 @@ frasesaniversarios.com.br: did not receive HSTS header
 frasesdeamizade.pt: could not connect to host
 frasys.io: did not receive HSTS header
 fraudempire.com: could not connect to host
-fredriksslekt.se: did not receive HSTS header
 freeasinlliure.org: did not receive HSTS header
 freeflow.tv: could not connect to host
 freekdevries.nl: did not receive HSTS header
@@ -6284,7 +6320,6 @@ ghid-pitesti.ro: did not receive HSTS header
 ghkim.net: could not connect to host
 ghostblog.info: did not receive HSTS header
 giakki.eu: could not connect to host
-gianlucapartengo.photography: did not receive HSTS header
 giant-powerfit.co.uk: did not receive HSTS header
 gibraltar-firma.com: did not receive HSTS header
 gidea.nu: could not connect to host
@@ -6642,9 +6677,7 @@ heathmanners.com: could not connect to host
 heavystresser.com: could not connect to host
 hebaus.com: could not connect to host
 heidilein.info: did not receive HSTS header
-heikorichter.name: did not receive HSTS header
 heimnetze.org: could not connect to host
-heinemeier.dk: did not receive HSTS header
 helencrump.co.uk: did not receive HSTS header
 helgakristoffer.com: could not connect to host
 helgakristoffer.wedding: could not connect to host
@@ -6793,8 +6826,6 @@ hppub.org: could not connect to host
 hppub.site: could not connect to host
 hqhost.net: did not receive HSTS header
 hr-intranet.com: could not connect to host
-hr-tech.shop: did not receive HSTS header
-hr-tech.store: did not receive HSTS header
 hrackydomino.cz: did not receive HSTS header
 hrfhomelottery.com: did not receive HSTS header
 hrk.io: could not connect to host
@@ -6813,7 +6844,6 @@ huarongdao.com: did not receive HSTS header
 hubert.systems: did not receive HSTS header
 hugocollignon.fr: could not connect to host
 humanesources.com: [Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsISiteSecurityService.processHeader]"  nsresult: "0x80004005 (NS_ERROR_FAILURE)"  location: "JS frame :: /builds/slave/m-cen-l64-periodicupdate-00000/getHSTSPreloadList.js :: processStsHeader :: line 116"  data: no]
-humblebee.co.uk: did not receive HSTS header
 humblefinances.com: did not receive HSTS header
 humeurs.net: could not connect to host
 humortuga.pt: could not connect to host
@@ -6847,6 +6877,7 @@ i-rickroll-n.pw: could not connect to host
 i10z.com: could not connect to host
 i496.eu: did not receive HSTS header
 iacono.com.br: did not receive HSTS header
+iamcarrico.com: did not receive HSTS header
 iamokay.nl: did not receive HSTS header
 iamreubin.co.uk: did not receive HSTS header
 iamveto.com: could not connect to host
@@ -6917,7 +6948,7 @@ ijn-dd.nl: could not connect to host
 ijoda.com: could not connect to host
 ik-life.com: did not receive HSTS header
 ikocik.sk: could not connect to host
-ikon.name: did not receive HSTS header
+ikon.name: could not connect to host
 ikwilguidobellen.nl: could not connect to host
 ikzoekjeugdhulp.nl: did not receive HSTS header
 ilbuongiorno.it: did not receive HSTS header
@@ -6957,7 +6988,7 @@ immunicity.rocks: could not connect to host
 immunicity.st: did not receive HSTS header
 immunicity.today: could not connect to host
 immunicity.top: could not connect to host
-immunicity.win: could not connect to host
+immunicity.win: max-age too low: 0
 immunicity.works: could not connect to host
 immunicity.world: could not connect to host
 imolug.org: did not receive HSTS header
@@ -6969,7 +7000,6 @@ imprenta-es.com: did not receive HSTS header
 imu.li: did not receive HSTS header
 imusic.dk: did not receive HSTS header
 imy.life: could not connect to host
-imydl.com: did not receive HSTS header
 inb4.us: could not connect to host
 inbox.li: did not receive HSTS header
 incendiary-arts.com: could not connect to host
@@ -6980,7 +7010,6 @@ indiecert.net: could not connect to host
 indiemods.com: could not connect to host
 indien.guide: could not connect to host
 indilens.com: did not receive HSTS header
-indochina.io: could not connect to host
 indoorskiassen.nl: did not receive HSTS header
 indredouglas.me: could not connect to host
 industrybazar.com: max-age too low: 2592000
@@ -7056,7 +7085,7 @@ internetradiocharts.de: did not receive HSTS header
 internshipandwork.com: did not receive HSTS header
 internshipandwork.ru: did not receive HSTS header
 interociter-enterprises.com: could not connect to host
-intersectraven.net: could not connect to host
+intersectraven.net: did not receive HSTS header
 interserved.com: did not receive HSTS header
 intervisteperstrada.com: could not connect to host
 intexplore.org: could not connect to host
@@ -7069,7 +7098,6 @@ intranetsec.fr: could not connect to host
 introvertedtravel.space: did not receive HSTS header
 intrp.net: did not receive HSTS header
 intxt.net: did not receive HSTS header
-inventtheworld.com.au: did not receive HSTS header
 investcountry.com: did not receive HSTS header
 investnext.com: max-age too low: 43200
 invictusmc.uk: could not connect to host
@@ -7237,6 +7265,7 @@ japaripark.com: could not connect to host
 japlex.com: could not connect to host
 jaqen.ch: could not connect to host
 jaredbates.net: did not receive HSTS header
+jarivisual.com: did not receive HSTS header
 jarnail.ca: did not receive HSTS header
 jaroslavtrsek.cz: did not receive HSTS header
 jarsater.com: could not connect to host
@@ -7273,7 +7302,6 @@ jcraft.us: did not receive HSTS header
 jctf.io: could not connect to host
 jdav-leipzig.de: could not connect to host
 jdgonzalez95.com: did not receive HSTS header
-jebengotai.com: could not connect to host
 jeff393.com: could not connect to host
 jeffreymagee.com: did not receive HSTS header
 jehovahsays.net: did not receive HSTS header
@@ -7342,6 +7370,7 @@ joakimalgroy.com: could not connect to host
 jobers.ch: did not receive HSTS header
 jobers.pt: did not receive HSTS header
 jobflyapp.com: could not connect to host
+joblab.com.ua: did not receive HSTS header
 jobshq.com: could not connect to host
 jobss.co.uk: could not connect to host
 jodel.ninja: did not receive HSTS header
@@ -7420,7 +7449,7 @@ junge-selbsthilfe.info: could not connect to host
 junglegoat.xyz: did not receive HSTS header
 junjung.me: could not connect to host
 junqtion.com: could not connect to host
-junqueiropolis.com: max-age too low: 0
+junqueiropolis.com: did not receive HSTS header
 jupp0r.de: did not receive HSTS header
 juristas.com.br: did not receive HSTS header
 jurke.com: did not receive HSTS header
@@ -7441,6 +7470,7 @@ jvoice.net: could not connect to host
 jvwdev.nl: did not receive HSTS header
 jwilsson.me: could not connect to host
 jxm.in: could not connect to host
+jym.fit: did not receive HSTS header
 jysperm.me: did not receive HSTS header
 jznet.org: could not connect to host
 k-dev.de: could not connect to host
@@ -7450,7 +7480,6 @@ k1cp.com: could not connect to host
 k38.cc: did not receive HSTS header
 ka-clan.com: could not connect to host
 kaanduman.com: did not receive HSTS header
-kaasbesteld.nl: did not receive HSTS header
 kaasbijwijn.nl: did not receive HSTS header
 kabinapp.com: could not connect to host
 kabuabc.com: could not connect to host
@@ -7531,7 +7560,6 @@ kermadec.blog: could not connect to host
 kermadec.net: could not connect to host
 kernl.us: did not receive HSTS header
 keskeces.com: did not receive HSTS header
-kevinmoreland.com: did not receive HSTS header
 kevinroebert.de: did not receive HSTS header
 keymaster.lookout.com: did not receive HSTS header
 kfbrussels.be: could not connect to host
@@ -7648,7 +7676,6 @@ kotovstyle.ru: could not connect to host
 koukni.cz: did not receive HSTS header
 kourpe.online: could not connect to host
 kousaku.jp: could not connect to host
-koyaanis.com: did not receive HSTS header
 kpdyer.com: did not receive HSTS header
 kpebetka.net: did not receive HSTS header
 kpn-dnssec.com: did not receive HSTS header
@@ -7741,6 +7768,7 @@ lahora.com.ec: did not receive HSTS header
 lainchan.org: did not receive HSTS header
 laisashop.com.br: could not connect to host
 lakarwebb.se: did not receive HSTS header
+lakehavasucityhomebuyerscredit.com: did not receive HSTS header
 laltroweb.it: did not receive HSTS header
 lamaland.ru: did not receive HSTS header
 lamarieealhonneur.com: did not receive HSTS header
@@ -7762,7 +7790,7 @@ landscape.canonical.com: max-age too low: 2592000
 landscapingmedic.com: did not receive HSTS header
 langenbach.rocks: could not connect to host
 langendries.eu: could not connect to host
-langhun.me: did not receive HSTS header
+langhun.me: could not connect to host
 laniakean.com: did not receive HSTS header
 lansinoh.co.uk: did not receive HSTS header
 lanzainc.xyz: did not receive HSTS header
@@ -7901,6 +7929,7 @@ lightnovelsekai.com: could not connect to host
 lightpaste.com: could not connect to host
 lightworkerandempathsupport.com: max-age too low: 300
 lightworx.io: did not receive HSTS header
+likeablehub.com: did not receive HSTS header
 lila.pink: did not receive HSTS header
 lilapmedia.com: could not connect to host
 lillpopp.eu: did not receive HSTS header
@@ -8014,7 +8043,7 @@ lothuytinhsi.com: could not connect to host
 lotos-ag.ch: did not receive HSTS header
 lotsencafe.de: did not receive HSTS header
 lottosonline.com: did not receive HSTS header
-lotuscloud.de: did not receive HSTS header
+lotuscloud.de: could not connect to host
 lotuscloud.org: could not connect to host
 louduniverse.net: did not receive HSTS header
 louiewatch.com: could not connect to host
@@ -8146,6 +8175,7 @@ makeitdynamic.com: could not connect to host
 makerstuff.net: did not receive HSTS header
 makeshiftco.de: did not receive HSTS header
 makeyourank.com: max-age too low: 200
+malash.me: did not receive HSTS header
 maldiverna.guide: could not connect to host
 maleexcel.com: did not receive HSTS header
 malena.com.ua: did not receive HSTS header
@@ -8193,6 +8223,7 @@ maosi.xin: could not connect to host
 maple5.com: could not connect to host
 maplenorth.co: did not receive HSTS header
 mapresidentielle.fr: did not receive HSTS header
+maranatha.pl: did not receive HSTS header
 marcelparra.com: could not connect to host
 marchagen.nl: did not receive HSTS header
 marchhappy.tech: did not receive HSTS header
@@ -8241,7 +8272,7 @@ martineve.com: did not receive HSTS header
 martinkup.cz: did not receive HSTS header
 martinp.no: could not connect to host
 martinreed.net: did not receive HSTS header
-martinrogalla.com: did not receive HSTS header
+martinrogalla.com: could not connect to host
 marumagic.com: did not receive HSTS header
 marvinkeller.de: did not receive HSTS header
 marykshoup.com: did not receive HSTS header
@@ -8314,7 +8345,6 @@ mcmillansedationdentistry.com: did not receive HSTS header
 mcooperlaw.com: did not receive HSTS header
 mcuexchange.com: did not receive HSTS header
 mdfnet.se: did not receive HSTS header
-mdkr.nl: did not receive HSTS header
 mdscomp.net: did not receive HSTS header
 meadowfenfarm.com: could not connect to host
 meat-education.com: could not connect to host
@@ -8328,7 +8358,6 @@ mediafinancelab.org: did not receive HSTS header
 mediamag.am: max-age too low: 0
 mediawikicn.org: could not connect to host
 medienservice-fritz.de: did not receive HSTS header
-medifab.online: did not receive HSTS header
 medirich.co: could not connect to host
 meditek-dv.ru: could not connect to host
 mediterenopmaandag.nl: did not receive HSTS header
@@ -8432,7 +8461,7 @@ midirs.org: did not receive HSTS header
 midonet.org: did not receive HSTS header
 midriversmotorsllc.com: did not receive HSTS header
 midwestwomenworkers.org: could not connect to host
-miegl.cz: could not connect to host
+miegl.cz: did not receive HSTS header
 miemie.jp: could not connect to host
 migeeks.de: did not receive HSTS header
 mightydicks.io: could not connect to host
@@ -8487,7 +8516,7 @@ minecraftforums.ml: could not connect to host
 minecraftserverz.com: could not connect to host
 minecraftvoter.com: could not connect to host
 mineover.es: could not connect to host
-mingo.nl: max-age too low: 2592000
+mingo.nl: could not connect to host
 minh.at: did not receive HSTS header
 mini-piraten.de: did not receive HSTS header
 minikneet.nl: could not connect to host
@@ -8640,6 +8669,7 @@ mountainmusicpromotions.com: did not receive HSTS header
 movabletype.net: max-age too low: 3600
 moviedollars.com: did not receive HSTS header
 moviesabout.net: could not connect to host
+moviespur.info: did not receive HSTS header
 movio.ga: did not receive HSTS header
 moy-gorod.od.ua: did not receive HSTS header
 mozart-game.cz: could not connect to host
@@ -8651,7 +8681,6 @@ mp3donusturucu.net: did not receive HSTS header
 mp3juices.is: max-age too low: 0
 mpintaamalabanna.it: did not receive HSTS header
 mpkossen.com: did not receive HSTS header
-mqas.net: did not receive HSTS header
 mr-hosting.com: could not connect to host
 mrawe.com: could not connect to host
 mrdani.net: could not connect to host
@@ -8772,7 +8801,6 @@ n-rickroll-e.pw: could not connect to host
 n0psled.nl: could not connect to host
 n2x.in: could not connect to host
 n4l.pw: could not connect to host
-n64chan.me: did not receive HSTS header
 n8ch.net: could not connect to host
 nabru.co.uk: did not receive HSTS header
 nabu-bad-nauheim.de: did not receive HSTS header
@@ -8804,6 +8832,7 @@ nanokamo.com: did not receive HSTS header
 nanrenba.net: could not connect to host
 nansay.cn: could not connect to host
 nanto.eu: could not connect to host
+naomiheji.com: did not receive HSTS header
 narach.com: did not receive HSTS header
 nargele.eu: did not receive HSTS header
 narodniki.com: did not receive HSTS header
@@ -8831,7 +8860,6 @@ navjobs.com: did not receive HSTS header
 nbb.io: could not connect to host
 nbg-ha.de: could not connect to host
 ncc60205.info: could not connect to host
-nchristo.com: did not receive HSTS header
 ncpc.gov: could not connect to host
 ncpw.gov: did not receive HSTS header
 nct.org.uk: did not receive HSTS header
@@ -8877,6 +8905,7 @@ netresourcedesign.com: could not connect to host
 netsafeid.biz: did not receive HSTS header
 netsparkercloud.com: did not receive HSTS header
 nettefoundation.com: could not connect to host
+nettia.fi: did not receive HSTS header
 netweaver.uk: did not receive HSTS header
 networx-online.de: could not connect to host
 netzbit.de: could not connect to host
@@ -9008,7 +9037,7 @@ notenoughtime.de: could not connect to host
 nothing.net.nz: max-age too low: 7776000
 noticia.do: did not receive HSTS header
 notjustbitchy.com: did not receive HSTS header
-nottheonion.net: could not connect to host
+nottheonion.net: did not receive HSTS header
 nou.si: could not connect to host
 nouvelle-vague-saint-cast.fr: did not receive HSTS header
 nova-elearning.com: could not connect to host
@@ -9505,6 +9534,7 @@ phdsupply.com: could not connect to host
 philadelphiacandies.com: did not receive HSTS header
 phillmoore.com: did not receive HSTS header
 phillprice.com: did not receive HSTS header
+philonas.net: did not receive HSTS header
 philpropertygroup.com: could not connect to host
 phoebe.co.nz: did not receive HSTS header
 phoenicis.com.ua: did not receive HSTS header
@@ -9517,6 +9547,7 @@ phototag.org: did not receive HSTS header
 php-bach.org: could not connect to host
 phperformances.fr: did not receive HSTS header
 phrasing.me: could not connect to host
+phurl.io: did not receive HSTS header
 physicaltherapist.com: did not receive HSTS header
 pi-eng.fr: did not receive HSTS header
 pianetaottica.net: could not connect to host
@@ -9693,7 +9724,7 @@ premioambiente.it: did not receive HSTS header
 premiumzweirad.de: max-age too low: 7776000
 prepandgo-euro.com: could not connect to host
 preparedcapital.com: max-age too low: 300
-preppertactics.com: did not receive HSTS header
+preppertactics.com: could not connect to host
 presidentials2016.com: could not connect to host
 press-anime-nenkan.com: did not receive HSTS header
 pressenews.net: did not receive HSTS header
@@ -9785,7 +9816,7 @@ pstudio.me: did not receive HSTS header
 psw.academy: could not connect to host
 psw.consulting: could not connect to host
 psylab.cc: did not receive HSTS header
-psylab.re: could not connect to host
+psylab.re: did not receive HSTS header
 psylab.vip: did not receive HSTS header
 ptn.moscow: could not connect to host
 ptonet.com: could not connect to host
@@ -9902,6 +9933,7 @@ raidstone.com: could not connect to host
 raidstone.net: could not connect to host
 raidstone.rocks: could not connect to host
 rainbowbarracuda.com: could not connect to host
+rainel.at: did not receive HSTS header
 ramarka.de: could not connect to host
 ramon-c.nl: could not connect to host
 ramonj.nl: could not connect to host
@@ -9953,6 +9985,7 @@ rcafox.com: could not connect to host
 rcorporation.be: did not receive HSTS header
 rcpcbd.com: could not connect to host
 rcvd.io: did not receive HSTS header
+rdmrotterdam.nl: did not receive HSTS header
 rdns.im: did not receive HSTS header
 rdyrda.fr: could not connect to host
 re-customer.net: did not receive HSTS header
@@ -10149,7 +10182,7 @@ rondoniatec.com.br: did not receive HSTS header
 ronvandordt.info: did not receive HSTS header
 ronwo.de: max-age too low: 1
 roo.ie: could not connect to host
-rool.me: could not connect to host
+rool.me: did not receive HSTS header
 rootforum.org: did not receive HSTS header
 rootservice.org: did not receive HSTS header
 rootwpn.com: could not connect to host
@@ -10157,6 +10190,7 @@ rop.io: could not connect to host
 roquecenter.org: did not receive HSTS header
 rorymcdaniel.com: did not receive HSTS header
 roseitsolutions.uk: did not receive HSTS header
+rossclark.com: did not receive HSTS header
 rossen.be: did not receive HSTS header
 rossiworld.com: did not receive HSTS header
 rotex1840.de: did not receive HSTS header
@@ -10173,7 +10207,7 @@ royalsignaturecruise.com: could not connect to host
 roychan.org: max-age too low: 0
 rozeapp.nl: could not connect to host
 rr.in.th: could not connect to host
-rrke.cc: could not connect to host
+rrke.cc: did not receive HSTS header
 rsajeey.info: could not connect to host
 rsampaio.info: did not receive HSTS header
 rsf.io: could not connect to host
@@ -10314,6 +10348,7 @@ schachburg.de: did not receive HSTS header
 schadegarant.net: could not connect to host
 schau-rein.co.at: did not receive HSTS header
 schauer.so: could not connect to host
+schd.io: did not receive HSTS header
 schermreparatierotterdam.nl: did not receive HSTS header
 schmitt.ovh: could not connect to host
 schnell-abnehmen.tips: did not receive HSTS header
@@ -10337,7 +10372,6 @@ schwetz.net: could not connect to host
 scicasts.com: max-age too low: 7776000
 scienceathome.org: did not receive HSTS header
 sciencebase.gov: did not receive HSTS header
-scionasset.com: did not receive HSTS header
 scivillage.com: did not receive HSTS header
 sckc.stream: could not connect to host
 sclgroup.cc: did not receive HSTS header
@@ -10410,6 +10444,7 @@ security-thoughts.org: could not connect to host
 securityarena.com: could not connect to host
 securitybsides.pl: did not receive HSTS header
 securityglance.com: could not connect to host
+securityheaders.io: did not receive HSTS header
 securityinet.biz: did not receive HSTS header
 securityinet.net: did not receive HSTS header
 securityinet.org.il: could not connect to host
@@ -10616,6 +10651,7 @@ simyo.nl: did not receive HSTS header
 sin30.net: could not connect to host
 sincai666.com: could not connect to host
 sincron.org: could not connect to host
+sinefili.com: did not receive HSTS header
 sinful.pw: could not connect to host
 singul4rity.com: could not connect to host
 sinneserweiterung.de: could not connect to host
@@ -10731,7 +10767,6 @@ snippet.host: could not connect to host
 snod.land: did not receive HSTS header
 snoozedds.com: max-age too low: 600
 snoqualmiefiber.org: could not connect to host
-snrat.com: did not receive HSTS header
 sobabox.ru: could not connect to host
 sobinski.pl: did not receive HSTS header
 soccergif.com: could not connect to host
@@ -11284,7 +11319,7 @@ the-delta.net.eu.org: could not connect to host
 the-paddies.de: did not receive HSTS header
 the-sky-of-valkyries.com: could not connect to host
 the.ie: max-age too low: 0
-theamateurs.net: could not connect to host
+theamateurs.net: did not receive HSTS header
 theamp.com: did not receive HSTS header
 theater.cf: could not connect to host
 theavenuegallery.com: did not receive HSTS header
@@ -11324,7 +11359,7 @@ thegreenpark.co.uk: did not receive HSTS header
 thegreenvpn.com: did not receive HSTS header
 thehiddenbay.eu: could not connect to host
 thehiddenbay.me: max-age too low: 0
-thehiddenbay.net: max-age too low: 0
+thehiddenbay.net: could not connect to host
 thehighersideclothing.com: did not receive HSTS header
 thehistory.me: could not connect to host
 thehonorguard.org: did not receive HSTS header
@@ -11384,7 +11419,6 @@ thisisforager.com: could not connect to host
 thiswasalreadymyusername.tk: could not connect to host
 thiswebhost.com: did not receive HSTS header
 thkb.net: could not connect to host
-thole.org: did not receive HSTS header
 thomas-ferney.fr: did not receive HSTS header
 thomas-gibertie.fr: did not receive HSTS header
 thomas-suchon.fr: did not receive HSTS header
@@ -11425,7 +11459,7 @@ tikutiku.pl: could not connect to host
 tildebot.com: could not connect to host
 tilient.eu: [Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsISiteSecurityService.processHeader]"  nsresult: "0x80004005 (NS_ERROR_FAILURE)"  location: "JS frame :: /builds/slave/m-cen-l64-periodicupdate-00000/getHSTSPreloadList.js :: processStsHeader :: line 116"  data: no]
 tilikum.io: did not receive HSTS header
-tilkah.com.au: could not connect to host
+tilkah.com.au: did not receive HSTS header
 tillcraft.com: could not connect to host
 timbeilby.com: could not connect to host
 timbuktutimber.com: did not receive HSTS header
@@ -11439,6 +11473,7 @@ timeserver1.de: could not connect to host
 timeserver2.de: could not connect to host
 timeserver3.de: could not connect to host
 timestamp.io: did not receive HSTS header
+timetab.org: did not receive HSTS header
 timhjalpen.se: could not connect to host
 timotrans.de: did not receive HSTS header
 timotrans.eu: did not receive HSTS header
@@ -11825,6 +11860,7 @@ ur-lauber.de: did not receive HSTS header
 urandom.eu.org: did not receive HSTS header
 urban-garden.lt: could not connect to host
 urban-garden.lv: could not connect to host
+urbanstylestaging.com: did not receive HSTS header
 urbpic.com: could not connect to host
 urlchomp.com: did not receive HSTS header
 urology.wiki: did not receive HSTS header
@@ -11865,7 +11901,7 @@ uzmandroid.net: could not connect to host
 uzmandroid.top: could not connect to host
 v-desk.ga: did not receive HSTS header
 v0rtex.xyz: could not connect to host
-v0tti.com: did not receive HSTS header
+v0tti.com: could not connect to host
 v12.co.uk: did not receive HSTS header
 v2.pw: did not receive HSTS header
 v2ex.us: could not connect to host
@@ -11873,7 +11909,7 @@ v4s.ro: did not receive HSTS header
 v4veedu.com: could not connect to host
 v7.cl: could not connect to host
 v789xl.com: did not receive HSTS header
-vaalmarketplace.co.za: could not connect to host
+vaalmarketplace.co.za: did not receive HSTS header
 vacationality.com: could not connect to host
 vackerbetong.se: could not connect to host
 vacuumreviewcenter.com: did not receive HSTS header
@@ -11895,6 +11931,7 @@ vampirism.eu: could not connect to host
 vanacht.co.za: did not receive HSTS header
 vanajahosting.com: did not receive HSTS header
 vanderkley.it: could not connect to host
+vanderrijt.nl: did not receive HSTS header
 vanestack.com: could not connect to host
 vanitas.xyz: did not receive HSTS header
 vanitynailworkz.com: could not connect to host
@@ -12109,14 +12146,12 @@ wapt.fr: did not receive HSTS header
 warandpeace.xyz: could not connect to host
 wardsegers.be: did not receive HSTS header
 warehost.de: did not receive HSTS header
-warekit.io: did not receive HSTS header
 warhistoryonline.com: did not receive HSTS header
 warped.com: did not receive HSTS header
 warrencreative.com: did not receive HSTS header
 warsentech.com: could not connect to host
 warsh.moe: did not receive HSTS header
 warumsuchen.at: did not receive HSTS header
-wasatchconstables.com: did not receive HSTS header
 wasatchcrest.com: did not receive HSTS header
 watchium.com: did not receive HSTS header
 waterforlife.net.au: did not receive HSTS header
@@ -12129,6 +12164,7 @@ wavefrontsystemstech.com: could not connect to host
 waylaydesign.com: did not receive HSTS header
 waylee.net: did not receive HSTS header
 wbci.us: did not receive HSTS header
+wealthformyhealth.com: did not receive HSTS header
 wear2work.nl: could not connect to host
 wearedisneyland.com: did not receive HSTS header
 weaverhairextensions.nl: could not connect to host
@@ -12228,6 +12264,7 @@ whatsstalk.me: could not connect to host
 whatsyouroffer.co.uk: did not receive HSTS header
 wheresben.today: could not connect to host
 whisker.network: could not connect to host
+whistler-transfers.com: did not receive HSTS header
 whitehat.id: could not connect to host
 whiterabbit.org: did not receive HSTS header
 whiterabbitcakery.com: could not connect to host
@@ -12320,7 +12357,6 @@ wordbits.net: did not receive HSTS header
 work-and-jockel.de: did not receive HSTS header
 workfone.io: could not connect to host
 workpermit.com.vn: could not connect to host
-worksofwyoming.org: did not receive HSTS header
 worldlist.org: could not connect to host
 worldpovertysolutions.org: did not receive HSTS header
 worldsbeststory.com: did not receive HSTS header
@@ -12332,9 +12368,7 @@ wowinvasion.com: did not receive HSTS header
 wp-rescue.com.au: did not receive HSTS header
 wpblog.com.tw: could not connect to host
 wpcarer.pro: could not connect to host
-wpcharged.nz: did not receive HSTS header
 wpfortify.com: could not connect to host
-wpg-inc.com: did not receive HSTS header
 wphome.org: could not connect to host
 wphostingspot.com: did not receive HSTS header
 wplatin.com: could not connect to host
@@ -12347,7 +12381,7 @@ wql.zj.cn: did not receive HSTS header
 wrbunderwriting.com: did not receive HSTS header
 wrfu.co.nz: did not receive HSTS header
 wrightdoumawedding.com: could not connect to host
-writeapp.me: did not receive HSTS header
+writeapp.me: could not connect to host
 wrldevelopment.com: did not receive HSTS header
 wroffle.com: did not receive HSTS header
 wrwg.ca: could not connect to host
@@ -12377,7 +12411,7 @@ www-8003.com: did not receive HSTS header
 www-88599.com: did not receive HSTS header
 www-9995.com: did not receive HSTS header
 www-djbet.com: did not receive HSTS header
-www-jinshavip.com: did not receive HSTS header
+www-jinshavip.com: could not connect to host
 www.cueup.com: could not connect to host
 www.cyveillance.com: did not receive HSTS header
 www.developer.mydigipass.com: could not connect to host
@@ -12512,7 +12546,7 @@ xtrim.ru: did not receive HSTS header
 xuexb.com: did not receive HSTS header
 xunn.io: did not receive HSTS header
 xupeng.me: did not receive HSTS header
-xuyh0120.win: could not connect to host
+xuyh0120.win: did not receive HSTS header
 xxbase.com: could not connect to host
 xynex.us: could not connect to host
 y-o-w.com: did not receive HSTS header
@@ -12620,7 +12654,6 @@ zao.fi: could not connect to host
 zaoshanghao-dajia.rhcloud.com: could not connect to host
 zap.yt: did not receive HSTS header
 zarooba.com: could not connect to host
-zary.me: did not receive HSTS header
 zavca.com: could not connect to host
 zbasenem.pl: did not receive HSTS header
 zbigniewgalucki.eu: did not receive HSTS header
@@ -12645,8 +12678,8 @@ zentience.org: did not receive HSTS header
 zentraler-kreditausschuss.de: did not receive HSTS header
 zentralwolke.de: did not receive HSTS header
 zenwears.com: could not connect to host
-zera.com.au: could not connect to host
-zerekin.net: did not receive HSTS header
+zera.com.au: max-age too low: 0
+zerekin.net: could not connect to host
 zeroday.sk: did not receive HSTS header
 zerofox.gq: could not connect to host
 zeroml.ml: could not connect to host
diff --git a/security/manager/ssl/nsSTSPreloadList.inc b/security/manager/ssl/nsSTSPreloadList.inc
index 580803c3e2d5..68f408c8cf24 100644
--- a/security/manager/ssl/nsSTSPreloadList.inc
+++ b/security/manager/ssl/nsSTSPreloadList.inc
@@ -8,7 +8,7 @@
 /*****************************************************************************/
 
 #include <stdint.h>
-const PRTime gPreloadListExpirationTime = INT64_C(1534452208072000);
+const PRTime gPreloadListExpirationTime = INT64_C(1534538708637000);
 %%
 0-1.party, 1
 0.me.uk, 1
@@ -1330,7 +1330,7 @@ acg18.us, 0
 acgaudio.com, 1
 acgpiano.club, 1
 achalay.org, 1
-acheconcursos.com.br, 1
+acheconcursos.com.br, 0
 achenar.net, 1
 acheter-ethylotest.fr, 1
 achow101.com, 1
@@ -1389,7 +1389,7 @@ activecare-monitor.com, 1
 activeclearweb.com, 1
 activehire.co.uk, 1
 activeleisure.ie, 1
-activeworld.net, 1
+activeworld.net, 0
 activitesaintnicaise.org, 1
 activityeventhire.co.uk, 1
 actom.cc, 1
@@ -1507,7 +1507,6 @@ adorecricket.com, 1
 adorewe.com, 1
 adoriasoft.com, 0
 adoucisseur.shop, 1
-adprospb.com, 1
 adquisitio.co.uk, 1
 adquisitio.es, 1
 adquisitio.fr, 1
@@ -2021,6 +2020,7 @@ alibangash.com, 1
 alibip.de, 1
 alice-noutore.com, 1
 alice.tw, 1
+alicestudio.it, 1
 alicetone.net, 1
 alicialab.org, 1
 alien.bz, 1
@@ -2091,6 +2091,7 @@ allinone-ranking150.com, 1
 allinonecyprus.com, 1
 allis.studio, 1
 alljamin.com, 1
+allkindzabeats.com, 1
 allladyboys.com, 1
 allmebel.ru, 1
 allmend-ru.de, 1
@@ -2200,6 +2201,7 @@ altitudemoversdenver.com, 1
 altkremsmuensterer.at, 1
 altoa.cz, 1
 altonblom.com, 1
+altoneum.com, 1
 altopartners.com, 1
 altopia.com, 1
 altphotos.com, 1
@@ -2291,7 +2293,6 @@ american.dating, 1
 americandistribuidora.com, 1
 americanfoundationbr.com, 1
 americanmediainstitute.com, 1
-americanoutlawjeepparts.com, 1
 americasbasementcontractor.com, 1
 americkykongres.cz, 1
 amerigroup.com, 1
@@ -2435,7 +2436,6 @@ andrewdaws.io, 1
 andrewdaws.me, 1
 andrewdaws.tv, 1
 andrewensley.com, 1
-andrewhowden.com, 1
 andrewimeson.com, 1
 andrewin.ru, 1
 andrewmichaud.com, 1
@@ -3756,7 +3756,6 @@ babystep.tv, 1
 bacgrouppublishing.com, 1
 bachata.info, 1
 baches-piscines.com, 1
-bacimg.com, 1
 baciu.ch, 1
 backeby.eu, 1
 backgroundz.net, 1
@@ -4039,6 +4038,7 @@ bauthier-occasions.be, 1
 bautied.de, 1
 bauunternehmen-herr.de, 1
 bayareaenergyevents.com, 1
+baychimo.com, 1
 bayden.com, 1
 bayer-stefan.com, 1
 bayer-stefan.de, 1
@@ -4774,7 +4774,7 @@ birdslabel.com, 1
 birdymanbestreviews.com, 1
 birgit-rydlewski.de, 1
 birkengarten.ch, 1
-birkhoff.me, 1
+birkhoff.me, 0
 birminghamcastlehire.co.uk, 1
 birminghamsunset.com, 1
 birthdaytip.com, 1
@@ -4789,6 +4789,7 @@ bismarck-tb.de, 1
 bison.co, 1
 bissalama.org, 1
 bisschopssteeg.nl, 1
+bistrocean.com, 1
 bistrotdelagare.fr, 1
 biswas.me, 1
 bit-cloud.de, 1
@@ -5218,7 +5219,6 @@ bologna-disinfestazioni.it, 1
 bolovegna.it, 1
 bolt.cm, 0
 bolte.org, 1
-boltn.uk, 1
 bomb.codes, 1
 bomberus.de, 1
 bombsquad.studio, 1
@@ -6068,7 +6068,6 @@ c2o2.xyz, 1
 c3.pm, 1
 c3vo.de, 1
 c3w.at, 1
-c4.hk, 1
 c4539.com, 1
 c4k3.net, 1
 c7dn.com, 1
@@ -6378,7 +6377,6 @@ carloshmm.com, 1
 carloshmm.stream, 1
 carlosjeurissen.com, 1
 carlovanwyk.com, 1
-carlscatering.com, 1
 carnaticalifornia.com, 1
 carnet-du-voyageur.com, 1
 carnildo.com, 1
@@ -6860,7 +6858,6 @@ chateau-de-lisle.fr, 1
 chateaudestrainchamps.com, 1
 chateaudevaugrigneuse.com, 1
 chatfacile.org, 1
-chatint.com, 1
 chatitaly.org, 1
 chatme.im, 0
 chatnbook.com, 1
@@ -7241,7 +7238,7 @@ cirugiasplasticas.com.mx, 1
 cirujanooral.com, 1
 cirurgicagervasio.com.br, 1
 cirurgicalucena.com.br, 1
-ciscodude.net, 0
+ciscodude.net, 1
 cisoaid.com, 1
 ciss.ltd, 1
 cisy.me, 1
@@ -7975,7 +7972,6 @@ constructive.men, 1
 consul.io, 1
 consultcelerity.com, 1
 consultingroupitaly.com, 1
-consultorcr.net, 1
 consultpetkov.com, 1
 consumeractionlawgroup.com, 1
 consumerfiles.com, 1
@@ -9580,7 +9576,6 @@ devpsy.info, 1
 devrandom.net, 1
 devstaff.gr, 1
 devtestfan1.gov, 1
-devyn.ca, 1
 devzero.io, 1
 dewaard.de, 1
 dewalch.net, 1
@@ -10008,6 +10003,7 @@ dmlogic.com, 1
 dmmkenya.co.ke, 1
 dmmultionderhoud.nl, 1
 dmschilderwerken.nl, 1
+dmwall.cn, 1
 dmxledlights.com, 1
 dn3s.me, 1
 dn42.eu, 0
@@ -10269,6 +10265,7 @@ doublestat.me, 1
 doubleup.com.au, 1
 doucheba.gs, 0
 dougferris.id.au, 1
+douglasstafford.com, 1
 doujin-domain.cz, 1
 doujin.nagoya, 1
 doujinshi.info, 1
@@ -10560,7 +10557,6 @@ duncancmt.com, 1
 duncanfamilytrust.org, 1
 duncanwinfrey.com, 1
 dundalkdonnie.com, 1
-dung-massage.fr, 1
 dungeon-bbs.de, 1
 dungi.org, 1
 dunklau.fr, 1
@@ -10593,6 +10589,7 @@ dustyspokesbnb.ca, 1
 dutch.desi, 1
 dutch1.nl, 1
 dutchdare.nl, 1
+dutchessuganda.com, 1
 dutchrank.nl, 1
 dutchwanderers.nl, 1
 dutchweballiance.nl, 1
@@ -10936,7 +10933,7 @@ educators.co.nz, 1
 educatoys.com.br, 1
 educnum.fr, 1
 eductf.org, 1
-eduid.se, 1
+eduid.se, 0
 eduif.nl, 0
 edumundo.nl, 1
 eduroam.no, 1
@@ -11189,6 +11186,7 @@ elfe.de, 1
 elgosblanc.com, 0
 elguadia.faith, 1
 elhall.pro, 1
+elhall.ru, 1
 elhamadimi.com, 1
 elhossari.com, 1
 elia.cloud, 1
@@ -11598,7 +11596,6 @@ equinox.io, 1
 equipandoloja.net.br, 1
 equipedefrance.tv, 1
 equipeferramentas.com.br, 1
-equippers.de, 1
 equipsupply.com, 1
 equk.co.uk, 1
 er-music.com, 1
@@ -12262,7 +12259,6 @@ extintormadrid.com, 1
 extradesktops.com, 0
 extranetpuc.com.br, 1
 extrapagetab.com, 1
-extratorrent.cool, 0
 extratorrent.fyi, 1
 extratorrent.red, 1
 extratorrent.world, 1
@@ -12601,7 +12597,6 @@ feastr-dev.de, 1
 feastr.de, 1
 feastr.io, 1
 featherweightlabs.com, 1
-featuredmen.com, 0
 feb.gov, 1
 fecik.sk, 1
 fed51.com, 1
@@ -12879,6 +12874,7 @@ fintry.ca, 1
 finvantage.com, 1
 fionamcbride.com, 1
 fiork.com, 1
+fioulmarket.fr, 1
 fir3net.com, 1
 fire-wolf.com, 1
 fireandelectrical.co.uk, 1
@@ -13433,6 +13429,7 @@ frederikschoell.de, 0
 frederikvig.com, 1
 fredliang.cn, 1
 fredloya.com, 1
+fredriksslekt.se, 1
 fredtec.ru, 1
 fredvoyage.fr, 1
 free-your-pc.com, 1
@@ -14365,6 +14362,7 @@ giac.org, 1
 giacomodrago.com, 1
 giacomodrago.it, 1
 giacomopelagatti.it, 1
+gianlucapartengo.photography, 1
 gianproperties.com, 1
 giant-panda.com, 1
 giant-tortoise.com, 1
@@ -15653,6 +15651,7 @@ heid.ws, 1
 heidisheroes.org, 1
 heijblok.com, 1
 heijdel.nl, 1
+heikorichter.name, 1
 heiland.io, 1
 heiliger-gral.info, 1
 heilpraxis-bgl.de, 1
@@ -15661,6 +15660,7 @@ heimdallr.nl, 1
 heimonen.eu, 1
 heimprofis.de, 1
 heinemann.io, 1
+heinemeier.dk, 1
 heinpost.nl, 0
 heinzelmann.co, 1
 heisenberg.co, 1
@@ -15945,7 +15945,7 @@ hinrich.de, 1
 hinterhofbu.de, 1
 hintermeier-rae.at, 1
 hinterposemuckel.de, 1
-hintss.pw, 1
+hintss.pw, 0
 hiphop.ren, 1
 hipi.jp, 1
 hipnoseinstitute.org, 1
@@ -16323,6 +16323,8 @@ hpnow.com.br, 1
 hqq.tv, 1
 hquest.pro.br, 1
 hqwebhosting.tk, 0
+hr-tech.shop, 1
+hr-tech.store, 1
 hr98.tk, 1
 hr98.xyz, 1
 hrabogados.com, 1
@@ -16448,6 +16450,7 @@ humblebee.be, 1
 humblebee.bg, 1
 humblebee.ch, 1
 humblebee.co.in, 1
+humblebee.co.uk, 1
 humblebee.com.mx, 1
 humblebee.com.ph, 1
 humblebee.cz, 1
@@ -16605,7 +16608,6 @@ iainsimms.co.uk, 1
 iainsimms.com, 1
 iainsimms.me, 1
 ialis.me, 1
-iamcarrico.com, 1
 iamhansen.xyz, 1
 iamjoshellis.com, 1
 iamle.com, 1
@@ -17022,6 +17024,7 @@ imrunner.com, 1
 imrunner.ru, 1
 ims-sargans.ch, 1
 imscompany.com, 1
+imydl.com, 1
 imydl.tech, 1
 imyunya.com, 1
 imyvm.com, 1
@@ -17077,6 +17080,7 @@ indigoinflatables.com, 1
 indigosakura.com, 1
 indiraactive.com, 1
 inditip.com, 1
+indochina.io, 1
 indogerman.de, 1
 indogermanstartup.com, 1
 indogermantrade.de, 1
@@ -17424,6 +17428,7 @@ inventix.nl, 1
 inventoryexpress.xyz, 1
 inventoryimages.co.uk, 1
 inventoryimages.com, 1
+inventtheworld.com.au, 1
 inventum.cloud, 1
 inverselink-user-content.com, 1
 inverselink.com, 1
@@ -18039,7 +18044,6 @@ jardins-utopie.net, 1
 jaredeberle.org, 0
 jaredfernandez.com, 1
 jaredfraser.com, 1
-jarivisual.com, 1
 jarl.ninja, 1
 jarniashop.se, 1
 jaroku.com, 1
@@ -18133,6 +18137,7 @@ jeanmarieayer.ch, 1
 jeannecalment.com, 1
 jeannelucienne.fr, 1
 jeanneret-combustibles.ch, 1
+jebengotai.com, 1
 jec-dekrone.be, 1
 jecho.cn, 1
 jedayoshi.me, 1
@@ -18350,7 +18355,6 @@ jobbkk.com, 1
 jobbsafari.no, 1
 jobbsafari.se, 1
 jobindex.dk, 1
-joblab.com.ua, 1
 joblife.co.za, 1
 jobmedic.com, 1
 jobmob.co.il, 1
@@ -18762,7 +18766,6 @@ jwolt-lx.com, 1
 jwschuepfheim.ch, 1
 jxir.de, 1
 jyggen.com, 1
-jym.fit, 1
 jyoti-fairworks.org, 1
 jzachpearson.com, 1
 jzbk.org, 1
@@ -18782,6 +18785,7 @@ k8r.eu, 1
 k9swx.com, 1
 kaamoscreations.com, 1
 kaangenc.me, 1
+kaasbesteld.nl, 1
 kaashosting.nl, 1
 kaatha-kamrater.se, 1
 kab-s.de, 1
@@ -19173,6 +19177,7 @@ kevinhq.com, 1
 kevinkla.es, 1
 kevinlocke.name, 1
 kevinmeijer.nl, 1
+kevinmoreland.com, 1
 kevinmorssink.nl, 1
 kevinpirnie.com, 1
 kevinratcliff.com, 1
@@ -19694,6 +19699,7 @@ kowalmik.tk, 1
 kowalstwo.com.pl, 1
 kowarschick.de, 1
 kowshiksundararajan.com, 1
+koyaanis.com, 1
 kozmik.co, 1
 kozuch.biz, 1
 kpfanworld.com, 1
@@ -20038,7 +20044,6 @@ lak-berlin.de, 1
 lakatrop.com, 1
 lakedavid.com.au, 1
 lakefrontlittleelm.com, 1
-lakehavasucityhomebuyerscredit.com, 1
 lakehavasucitynews.com, 1
 lakehavasuhomebuyercredit.com, 1
 lakehavasuhomes.info, 1
@@ -20729,7 +20734,6 @@ lihaul.dnsalias.net, 1
 lijero.co, 1
 likc.me, 1
 like.lgbt, 1
-likeablehub.com, 1
 likeabox.de, 1
 likeaross.com, 0
 likegeeks.com, 1
@@ -21698,7 +21702,6 @@ maktoob.search.yahoo.com, 0
 maku.edu.tr, 1
 malachiteauth.com, 1
 malamutedoalasca.com.br, 1
-malash.me, 1
 malasuk.com, 1
 malaysia.search.yahoo.com, 0
 malaysian.dating, 1
@@ -21844,7 +21847,6 @@ maquinariaspesadas.org, 1
 mar-eco.no, 1
 marabumadrid.com, 1
 marakovits.net, 1
-maranatha.pl, 1
 marbinvest.com, 1
 marble.com, 1
 marbogardenlidkoping.se, 1
@@ -22331,6 +22333,7 @@ mdek.at, 1
 mdewendt.de, 1
 mdf-bis.com, 1
 mdiv.pl, 1
+mdkr.nl, 1
 mdlayher.com, 1
 mdma.net, 1
 mdmed.clinic, 1
@@ -22412,6 +22415,7 @@ medicinskavranje.edu.rs, 1
 medicocompetente.it, 1
 medicoresponde.com.br, 1
 medienweite.de, 1
+medifab.online, 1
 medifi.com, 1
 medigap-quote.net, 1
 medinside.ch, 1
@@ -23498,7 +23502,6 @@ movienang.com, 1
 movienized.de, 1
 moviepilot.com, 1
 moviesetc.net, 1
-moviespur.info, 1
 movil.uno, 1
 movimento-terra.it, 1
 moving-pixtures.de, 1
@@ -23537,6 +23540,7 @@ mpserver12.org, 1
 mpsgarage.com.au, 1
 mpsoundcraft.com, 1
 mpy.ovh, 1
+mqas.net, 1
 mr-anderson.org, 1
 mr-coffee.net, 1
 mr-labo.jp, 1
@@ -24094,6 +24098,7 @@ n26.com, 1
 n2servers.com, 1
 n3twork.net, 1
 n4v.eu, 1
+n64chan.me, 1
 n6a.net, 1
 n7.education, 1
 na-school.nl, 1
@@ -24118,7 +24123,7 @@ nadyaolcer.fr, 1
 nafod.net, 1
 naga-semi.com, 1
 nagaragem.com.br, 1
-nagashi.ma, 1
+nagashi.ma, 0
 nagaya.biz, 1
 nagb.gov, 1
 nagb.org, 1
@@ -24182,7 +24187,6 @@ nanubo.com, 1
 nanubo.de, 1
 naoar.com, 1
 naomi.es, 0
-naomiheji.com, 1
 naotone.com, 1
 napcae.de, 1
 naphex.rocks, 1
@@ -24365,6 +24369,7 @@ ncconsumer.org, 1
 ncdesigns-studio.com, 1
 ncea.net.au, 1
 nchangfong.com, 1
+nchristo.com, 1
 ncic.gg, 1
 nclvle.co.uk, 1
 ncrmnt.org, 1
@@ -24581,7 +24586,6 @@ netsystems.pro, 1
 nettamente.com, 1
 nette.org, 1
 nettegeschenke.de, 1
-nettia.fi, 1
 netto-service.ch, 1
 nettools.link, 1
 nettopower.dk, 1
@@ -26847,7 +26851,6 @@ philippheenen.de, 1
 philippkeschl.at, 1
 phillipgoldfarb.com, 1
 phillippi.me, 1
-philonas.net, 1
 philosoftware.com.br, 1
 philosopherswool.com, 1
 philosophyguides.org, 1
@@ -26911,7 +26914,6 @@ phuket-idc.de, 1
 phunehehe.net, 1
 phuong.faith, 1
 phurl.de, 1
-phurl.io, 1
 phus.lu, 1
 physicalism.com, 1
 physicalist.com, 1
@@ -28505,7 +28507,6 @@ rainbowbay.org, 1
 rainbowinflatables.co.uk, 1
 rainbowstore.com.au, 1
 rainbowstore.com.ua, 1
-rainel.at, 1
 rainforest.engineering, 1
 rainpaper.com, 1
 rainstormsinjuly.co, 1
@@ -28668,7 +28669,6 @@ rdfproject.it, 1
 rdfz.tech, 1
 rdh.asia, 1
 rdl.at, 0
-rdmrotterdam.nl, 1
 rdmtaxservice.com, 1
 rdns.cc, 1
 re-curi.com, 1
@@ -28950,7 +28950,7 @@ rejahrehim.com, 1
 rejsehuskelisten.dk, 1
 rejushiiplotter.ru, 1
 rekorsanat.com.tr, 1
-rekyou.com, 1
+rekyou.com, 0
 relates.link, 1
 relatethesport.com, 0
 relatic.net, 1
@@ -29576,7 +29576,6 @@ rosewoodranch.com, 1
 rosi-royal.com, 1
 roslynpad.net, 1
 rospa100.com, 1
-rossclark.com, 1
 rosset.me, 1
 rosset.net, 1
 rossfrancis.co.uk, 1
@@ -30262,7 +30261,6 @@ schaper-sport.com, 1
 schatmeester.be, 1
 schatzibaers.de, 1
 schawe.me, 1
-schd.io, 1
 scheduleme.io, 1
 scheemadigital.com, 1
 schefczyk.com, 1
@@ -30398,6 +30396,7 @@ scijinks.gov, 1
 scimage.com, 1
 scintilla.nl, 1
 scintillating.stream, 1
+scionasset.com, 1
 scis.com.ua, 1
 scistarter.com, 1
 scitopia.me, 1
@@ -30622,7 +30621,6 @@ securitybrief.com.au, 1
 securitybrief.eu, 1
 securityfest.com, 1
 securityheaders.com, 1
-securityheaders.io, 1
 securityinet.com, 0
 securitykey.co, 1
 securitymap.wiki, 1
@@ -31459,7 +31457,6 @@ sinatrafamily.com, 1
 sinceschool.com, 1
 sinclairinat0r.com, 1
 sinde.ru, 1
-sinefili.com, 1
 sinergy.ch, 1
 sinfield.com, 0
 sinfulforums.net, 1
@@ -31656,7 +31653,7 @@ sladic.si, 0
 slainvet.net, 1
 slamdjapan.com, 1
 slamix.nl, 1
-slane.cn, 1
+slane.cn, 0
 slangbellor.com, 1
 slapen17.nl, 1
 slaps.be, 1
@@ -31902,6 +31899,7 @@ snowhaze.ch, 1
 snowhaze.com, 1
 snowplane.net, 1
 snowraven.de, 1
+snrat.com, 1
 snrub.co, 1
 snuff.porn, 1
 snughealth.org.uk, 1
@@ -34376,6 +34374,7 @@ thisoldearth.com, 1
 thisserver.dontexist.net, 1
 thistleandleaves.com, 1
 thm.vn, 1
+thole.org, 1
 thom4s.info, 1
 thomalaudan.de, 1
 thomas-bertran.com, 1
@@ -34537,7 +34536,6 @@ timeglass.de, 1
 timer.fit, 1
 timersuite.com, 1
 timestamp.uk, 1
-timetab.org, 1
 timetech.io, 1
 timetotrade.com, 1
 timewasters.nl, 1
@@ -35944,7 +35942,6 @@ urbanmelbourne.info, 1
 urbanmic.com, 1
 urbannewsservice.com, 1
 urbansparrow.in, 1
-urbanstylestaging.com, 1
 urbanwildlifealliance.org, 0
 urbexdk.nl, 1
 urcentral.com, 1
@@ -36156,7 +36153,6 @@ vanderbiltcisa.org, 1
 vanderkrieken.org, 1
 vanderkroon.nl, 1
 vandermeer.frl, 1
-vanderrijt.nl, 1
 vanderstraeten.dynv6.net, 1
 vanderziel.org, 1
 vaneigenkweek.be, 1
@@ -36734,7 +36730,7 @@ volgavibes.ru, 0
 voliere-info.nl, 0
 volker-gropp.de, 1
 volkergropp.de, 1
-volkerwesselstransfer.nl, 1
+volkerwesselstransfer.nl, 0
 volkerwesselswave.nl, 0
 volkswurst.de, 1
 vollans.id.au, 1
@@ -36763,7 +36759,7 @@ vorodevops.com, 1
 vos-fleurs.ch, 1
 vos-fleurs.com, 1
 vosgym.jp, 1
-voshod.org, 0
+voshod.org, 1
 vosjesweb.nl, 1
 vosky.fr, 1
 vosn.de, 1
@@ -36980,6 +36976,7 @@ waonui.io, 1
 warcraftjournal.org, 1
 wardow.com, 1
 warebouncycastles.co.uk, 1
+warekit.io, 1
 warekon.com, 1
 warekon.dk, 1
 warenits.at, 0
@@ -36996,6 +36993,7 @@ warr.ath.cx, 1
 warringtonkidsbouncycastles.co.uk, 1
 warschild.org, 1
 wartorngalaxy.com, 1
+wasatchconstables.com, 1
 waschpark-hantschel.de, 1
 wasema.com, 1
 wasfestes.de, 1
@@ -37073,7 +37071,6 @@ we.serveftp.net, 1
 weacceptbitcoin.gr, 1
 wealthcentral.com.au, 1
 wealthfactory.com, 0
-wealthformyhealth.com, 1
 wealthprojector.com, 1
 wealthprojector.com.au, 1
 wealthreport.com.au, 1
@@ -37506,7 +37503,6 @@ whisperinghoperanch.org, 1
 whisperlab.org, 1
 whistleb.com, 1
 whistleblower.gov, 1
-whistler-transfers.com, 1
 whitby-brewery.com, 1
 whitealps.at, 1
 whitealps.be, 1
@@ -37882,6 +37878,7 @@ workray.com, 1
 works-ginan.jp, 1
 workshopszwolle.nl, 1
 workshopzwolle.com, 1
+worksofwyoming.org, 1
 workwithgo.com, 1
 world-education-association.org, 1
 world-in-my-eyes.com, 1
@@ -37939,12 +37936,14 @@ wpac.de, 1
 wpandup.org, 1
 wpcanban.com, 1
 wpcdn.bid, 1
+wpcharged.nz, 1
 wpcheck.io, 1
 wpdesigner.ir, 1
 wpdirecto.com, 1
 wpdublin.com, 1
 wpenhance.com, 1
 wpformation.com, 1
+wpg-inc.com, 1
 wphelpwithhomework.tk, 1
 wphostingblog.nl, 1
 wpinfos.de, 1
@@ -39020,6 +39019,7 @@ zargaripour.com, 1
 zargescases.co.uk, 1
 zarmarket.org, 1
 zarpo.com.br, 1
+zary.me, 1
 zatsepin.by, 1
 zaufanatrzeciastrona.pl, 1
 zavec.com.ec, 1
@@ -39239,7 +39239,7 @@ zoola.io, 1
 zoological-gardens.eu, 1
 zoom.earth, 1
 zoomek.com, 1
-zoomseoservices.com, 1
+zoomseoservices.com, 0
 zooom.azurewebsites.net, 1
 zooom2.azurewebsites.net, 1
 zooparadies.eu, 1
diff --git a/servo/components/style/gecko/rules.rs b/servo/components/style/gecko/rules.rs
index ccf49f829700..2f1442796569 100644
--- a/servo/components/style/gecko/rules.rs
+++ b/servo/components/style/gecko/rules.rs
@@ -25,7 +25,7 @@ impl<'a> ToNsCssValue for &'a FamilyName {
 
 impl ToNsCssValue for font_weight::T {
     fn convert(self, nscssvalue: &mut nsCSSValue) {
-        nscssvalue.set_integer(self.0 as i32)
+        nscssvalue.set_font_weight(self.0)
     }
 }
 
@@ -34,7 +34,7 @@ impl<'a> ToNsCssValue for &'a FontWeight {
         match *self {
             FontWeight::Normal => nscssvalue.set_enum(structs::NS_FONT_WEIGHT_NORMAL as i32),
             FontWeight::Bold => nscssvalue.set_enum(structs::NS_FONT_WEIGHT_BOLD as i32),
-            FontWeight::Weight(weight) => nscssvalue.set_integer(weight.0 as i32),
+            FontWeight::Weight(weight) => nscssvalue.set_font_weight(weight.0),
         }
     }
 }
diff --git a/servo/components/style/gecko_bindings/sugar/ns_css_value.rs b/servo/components/style/gecko_bindings/sugar/ns_css_value.rs
index 4507e3fbd6b7..456935615106 100644
--- a/servo/components/style/gecko_bindings/sugar/ns_css_value.rs
+++ b/servo/components/style/gecko_bindings/sugar/ns_css_value.rs
@@ -177,6 +177,11 @@ impl nsCSSValue {
         self.set_string_from_atom_internal(s, nsCSSUnit::eCSSUnit_Local_Font);
     }
 
+    /// Set to a font weight
+    pub fn set_font_weight(&mut self, w: u16) {
+        unsafe { bindings::Gecko_CSSValue_SetFontWeight(self, w as f32) }
+    }
+
     fn set_int_internal(&mut self, value: i32, unit: nsCSSUnit) {
         unsafe { bindings::Gecko_CSSValue_SetInt(self, value, unit) }
     }
diff --git a/servo/components/style/properties/gecko.mako.rs b/servo/components/style/properties/gecko.mako.rs
index 16c75025f41f..067d014442d4 100644
--- a/servo/components/style/properties/gecko.mako.rs
+++ b/servo/components/style/properties/gecko.mako.rs
@@ -25,6 +25,8 @@ use gecko_bindings::bindings::Gecko_CopyFontFamilyFrom;
 use gecko_bindings::bindings::Gecko_CopyImageValueFrom;
 use gecko_bindings::bindings::Gecko_CopyListStyleImageFrom;
 use gecko_bindings::bindings::Gecko_EnsureImageLayersLength;
+use gecko_bindings::bindings::Gecko_FontWeight_SetFloat;
+use gecko_bindings::bindings::Gecko_FontWeight_ToFloat;
 use gecko_bindings::bindings::Gecko_SetCursorArrayLength;
 use gecko_bindings::bindings::Gecko_SetCursorImageValue;
 use gecko_bindings::bindings::Gecko_StyleTransition_SetUnsupportedProperty;
@@ -2599,13 +2601,15 @@ fn static_assert() {
     }
 
     pub fn set_font_weight(&mut self, v: longhands::font_weight::computed_value::T) {
-        self.gecko.mFont.weight = v.0;
+        unsafe { Gecko_FontWeight_SetFloat(&mut self.gecko.mFont.weight, v.0 as f32) };
     }
     ${impl_simple_copy('font_weight', 'mFont.weight')}
 
     pub fn clone_font_weight(&self) -> longhands::font_weight::computed_value::T {
-        debug_assert!(self.gecko.mFont.weight <= ::std::u16::MAX);
-        longhands::font_weight::computed_value::T(self.gecko.mFont.weight)
+        let weight: f32 = unsafe { Gecko_FontWeight_ToFloat(self.gecko.mFont.weight) };
+        debug_assert!(weight >= 0.0 &&
+                      weight <= ::std::u16::MAX as f32);
+        longhands::font_weight::computed_value::T(weight as u16)
     }
 
     ${impl_simple_type_with_conversion("font_synthesis", "mFont.synthesis")}
diff --git a/servo/components/style/values/computed/font.rs b/servo/components/style/values/computed/font.rs
index 0863311fe17b..c270969a52f1 100644
--- a/servo/components/style/values/computed/font.rs
+++ b/servo/components/style/values/computed/font.rs
@@ -75,10 +75,12 @@ impl FontWeight {
     }
 
     /// Convert from an Gecko weight
-    pub fn from_gecko_weight(weight: u16) -> Self {
+    #[cfg(feature = "gecko")]
+    pub fn from_gecko_weight(weight: structs::FontWeight) -> Self {
         // we allow a wider range of weights than is parseable
         // because system fonts may provide custom values
-        FontWeight(weight)
+        let weight = unsafe { bindings::Gecko_FontWeight_ToFloat(weight) };
+        FontWeight(weight as u16)
     }
 
     /// Weither this weight is bold
diff --git a/taskcluster/ci/config.yml b/taskcluster/ci/config.yml
index 67dece91d655..e56b3569ce7c 100755
--- a/taskcluster/ci/config.yml
+++ b/taskcluster/ci/config.yml
@@ -1,4 +1,5 @@
 trust-domain: gecko
+project-repo-param-prefix: ''
 treeherder:
     group-names:
         'cram': 'Cram tests'
diff --git a/taskcluster/ci/repo-update-bb/kind.yml b/taskcluster/ci/repo-update-bb/kind.yml
deleted file mode 100644
index 2c6576484eaa..000000000000
--- a/taskcluster/ci/repo-update-bb/kind.yml
+++ /dev/null
@@ -1,21 +0,0 @@
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-loader: taskgraph.loader.transform:loader
-
-transforms:
-   - taskgraph.transforms.job:transforms
-   - taskgraph.transforms.task:transforms
-
-
-jobs:
-   hsts-hpkp-blocklist:
-      name: periodic_file_update
-      description: HSTS, HPKP, and Blocklist update
-      worker-type: buildbot-bridge/buildbot-bridge
-      run-on-projects: []  # Only run via cron
-      run:
-         using: buildbot
-         product: firefox
-         buildername: Linux x86-64 {branch} periodic file update
diff --git a/taskcluster/docs/actions.rst b/taskcluster/docs/actions.rst
index a3497e0c597f..92fc9437a54d 100644
--- a/taskcluster/docs/actions.rst
+++ b/taskcluster/docs/actions.rst
@@ -52,7 +52,7 @@ To create a new callback action you must create a file
       description="Simple **proof-of-concept** callback action",
       order=10000,  # Order in which it should appear relative to other actions
   )
-  def hello_world_action(parameters, input, task_group_id, task_id, task):
+  def hello_world_action(parameters, graph_config, input, task_group_id, task_id, task):
       # parameters is an instance of taskgraph.parameters.Parameters
       # it carries decision task parameters from the original decision task.
       # input, task_id, and task should all be None
@@ -112,7 +112,7 @@ The example action below will be shown in the context-menu for tasks with
       order=1,
       context=[{'platform': 'linux'}]
   )
-  def retrigger_action(parameters, input, task_group_id, task_id, task):
+  def retrigger_action(parameters, graph_config, input, task_group_id, task_id, task):
       # input will be None
       print "Retriggering: {}".format(task_id)
       print "task definition: {}".format(task)
@@ -175,7 +175,7 @@ both ``input`` and ``context``::
           'additionalProperties': False,
       },
   )
-  def retrigger_action(parameters, input, task_group_id, task_id, task):
+  def retrigger_action(parameters, graph_config, input, task_group_id, task_id, task):
       print "Create all pruned tasks with priority: {}".format(input['priority'])
       if input['runTalos']:
           print "Also running talos jobs..."
@@ -211,7 +211,7 @@ The feature is illustrated below::
       # Define an action that is only included if this is a push to try
       available=lambda parameters: parameters.get('project', None) == 'try',
   )
-  def try_only_action(parameters, input, task_group_id, task_id, task):
+  def try_only_action(parameters, graph_config, input, task_group_id, task_id, task):
       print "My try-only action"
 
 Properties of ``parameters``  are documented in the
@@ -245,7 +245,7 @@ The example below illustrates how to create such an action in Python::
           'default': 'low',
       },
   )
-  def task_template_builder(parameters):
+  def task_template_builder(parameters, graph_config):
       # The task template builder may return None to signal that the action
       # isn't available.
       if parameters.get('project', None) != 'try':
diff --git a/taskcluster/docs/kinds.rst b/taskcluster/docs/kinds.rst
index fb202d09ea14..569e05541e17 100644
--- a/taskcluster/docs/kinds.rst
+++ b/taskcluster/docs/kinds.rst
@@ -375,12 +375,6 @@ repo-update
 Repo-Update tasks are tasks that perform some action on the project repo itself,
 in order to update its state in some way.
 
-repo-update-bb
---------------
-Repo-Update tasks are tasks that perform some action on the project repo itself,
-in order to update its state in some way. This kind is the older, buildbot version.
-It will be removed after the migration to taskcluster.
-
 partials
 --------
 Partials takes the complete.mar files produced in previous tasks and generates partial
diff --git a/taskcluster/mach_commands.py b/taskcluster/mach_commands.py
index 630fb168fe16..bfe8c7c6f199 100644
--- a/taskcluster/mach_commands.py
+++ b/taskcluster/mach_commands.py
@@ -212,6 +212,8 @@ class MachCommands(MachCommandBase):
 
     @SubCommand('taskgraph', 'action-callback',
                 description='Run action callback used by action tasks')
+    @CommandArgument('--root', '-r', default='taskcluster/ci',
+                     help="root of the taskgraph definition relative to topsrcdir")
     def action_callback(self, **options):
         import taskgraph.actions
         try:
@@ -223,6 +225,7 @@ class MachCommands(MachCommandBase):
             input = json.loads(os.environ.get('ACTION_INPUT', 'null'))
             callback = os.environ.get('ACTION_CALLBACK', None)
             parameters = json.loads(os.environ.get('ACTION_PARAMETERS', '{}'))
+            root = options['root']
 
             return taskgraph.actions.trigger_action_callback(
                     task_group_id=task_group_id,
@@ -231,6 +234,7 @@ class MachCommands(MachCommandBase):
                     input=input,
                     callback=callback,
                     parameters=parameters,
+                    root=root,
                     test=False)
         except Exception:
             traceback.print_exc()
@@ -238,6 +242,8 @@ class MachCommands(MachCommandBase):
 
     @SubCommand('taskgraph', 'test-action-callback',
                 description='Run an action callback in a testing mode')
+    @CommandArgument('--root', '-r', default='taskcluster/ci',
+                     help="root of the taskgraph definition relative to topsrcdir")
     @CommandArgument('--parameters', '-p', default='project=mozilla-central',
                      help='parameters file (.yml or .json; see '
                           '`taskcluster/docs/parameters.rst`)`')
@@ -285,6 +291,8 @@ class MachCommands(MachCommandBase):
             parameters = taskgraph.parameters.load_parameters_file(options['parameters'])
             parameters.check()
 
+            root = options['root']
+
             return taskgraph.actions.trigger_action_callback(
                     task_group_id=options['task_group_id'],
                     task_id=task_id,
@@ -292,6 +300,7 @@ class MachCommands(MachCommandBase):
                     input=input,
                     callback=options['callback'],
                     parameters=parameters,
+                    root=root,
                     test=True)
         except Exception:
             traceback.print_exc()
diff --git a/taskcluster/taskgraph/actions/add_new_jobs.py b/taskcluster/taskgraph/actions/add_new_jobs.py
index a7a64e17931c..60b0b8736be7 100644
--- a/taskcluster/taskgraph/actions/add_new_jobs.py
+++ b/taskcluster/taskgraph/actions/add_new_jobs.py
@@ -31,8 +31,9 @@ from .util import (create_tasks, fetch_graph_and_labels)
         }
     }
 )
-def add_new_jobs_action(parameters, input, task_group_id, task_id, task):
-    decision_task_id, full_task_graph, label_to_taskid = fetch_graph_and_labels(parameters)
+def add_new_jobs_action(parameters, graph_config, input, task_group_id, task_id, task):
+    decision_task_id, full_task_graph, label_to_taskid = fetch_graph_and_labels(
+        parameters, graph_config)
 
     to_run = []
     for elem in input['tasks']:
diff --git a/taskcluster/taskgraph/actions/add_talos.py b/taskcluster/taskgraph/actions/add_talos.py
index 6c141bde453d..2698529f295e 100644
--- a/taskcluster/taskgraph/actions/add_talos.py
+++ b/taskcluster/taskgraph/actions/add_talos.py
@@ -36,8 +36,9 @@ logger = logging.getLogger(__name__)
         'additionalProperties': False
     },
 )
-def add_all_talos(parameters, input, task_group_id, task_id, task):
-    decision_task_id, full_task_graph, label_to_taskid = fetch_graph_and_labels(parameters)
+def add_all_talos(parameters, graph_config, input, task_group_id, task_id, task):
+    decision_task_id, full_task_graph, label_to_taskid = fetch_graph_and_labels(
+        parameters, graph_config)
 
     times = input.get('times', 1)
     for i in xrange(times):
diff --git a/taskcluster/taskgraph/actions/backfill.py b/taskcluster/taskgraph/actions/backfill.py
index 4de8086914d7..4ca1898a699a 100644
--- a/taskcluster/taskgraph/actions/backfill.py
+++ b/taskcluster/taskgraph/actions/backfill.py
@@ -48,7 +48,7 @@ logger = logging.getLogger(__name__)
     },
     available=lambda parameters: parameters.get('project', None) != 'try'
 )
-def backfill_action(parameters, input, task_group_id, task_id, task):
+def backfill_action(parameters, graph_config, input, task_group_id, task_id, task):
     label = task['metadata']['name']
     pushes = []
     depth = input.get('depth', 5)
@@ -82,7 +82,7 @@ def backfill_action(parameters, input, task_group_id, task_id, task):
             push_params = get_artifact_from_index(
                     INDEX_TMPL.format(parameters['project'], push),
                     'public/parameters.yml')
-            push_decision_task_id = find_decision_task(push_params)
+            push_decision_task_id = find_decision_task(push_params, graph_config)
         except HTTPError as e:
             logger.info('Skipping {} due to missing index artifacts! Error: {}'.format(push, e))
             continue
diff --git a/taskcluster/taskgraph/actions/mochitest_retrigger.py b/taskcluster/taskgraph/actions/mochitest_retrigger.py
index 496ba16c61d1..e877a6346a7b 100644
--- a/taskcluster/taskgraph/actions/mochitest_retrigger.py
+++ b/taskcluster/taskgraph/actions/mochitest_retrigger.py
@@ -79,8 +79,9 @@ logger = logging.getLogger(__name__)
         'required': ['path']
     }
 )
-def mochitest_retrigger_action(parameters, input, task_group_id, task_id, task):
-    decision_task_id, full_task_graph, label_to_taskid = fetch_graph_and_labels(parameters)
+def mochitest_retrigger_action(parameters, graph_config, input, task_group_id, task_id, task):
+    decision_task_id, full_task_graph, label_to_taskid = fetch_graph_and_labels(
+        parameters, graph_config)
 
     pre_task = full_task_graph.tasks[task['metadata']['name']]
 
diff --git a/taskcluster/taskgraph/actions/registry.py b/taskcluster/taskgraph/actions/registry.py
index f2516c906c68..09d74889375b 100644
--- a/taskcluster/taskgraph/actions/registry.py
+++ b/taskcluster/taskgraph/actions/registry.py
@@ -11,10 +11,10 @@ import os
 import re
 import yaml
 from slugid import nice as slugid
-from mozbuild.util import memoize
 from types import FunctionType
 from collections import namedtuple
 from taskgraph import create, GECKO
+from taskgraph.generator import load_graph_config
 from taskgraph.util import taskcluster
 from taskgraph.parameters import Parameters
 
@@ -173,19 +173,26 @@ def register_callback_action(name, title, symbol, description, order=10000,
         assert cb.__name__ not in callbacks, 'callback name {} is not unique'.format(cb.__name__)
 
         @register_task_action(name, title, description, order, context, schema)
-        def build_callback_action_task(parameters):
+        def build_callback_action_task(parameters, graph_config):
             if not available(parameters):
                 return None
 
-            match = re.match(r'https://(hg.mozilla.org)/(.*?)/?$', parameters['head_repository'])
+            repo_param = '{}head_repository'.format(graph_config['project-repo-param-prefix'])
+            revision = parameters['{}head_rev'.format(graph_config['project-repo-param-prefix'])]
+            match = re.match(r'https://(hg.mozilla.org)/(.*?)/?$', parameters[repo_param])
             if not match:
-                raise Exception('Unrecognized head_repository')
+                raise Exception('Unrecognized {}'.format(repo_param))
             repo_scope = 'assume:repo:{}/{}:branch:default'.format(
                 match.group(1), match.group(2))
 
             task_group_id = os.environ.get('TASK_ID', slugid())
 
-            template = os.path.join(GECKO, '.taskcluster.yml')
+            # FIXME: https://bugzilla.mozilla.org/show_bug.cgi?id=1454034
+            # trust-domain works, but isn't semantically correct here.
+            if graph_config['trust-domain'] == 'comm':
+                template = os.path.join(GECKO, 'comm', '.taskcluster.yml')
+            else:
+                template = os.path.join(GECKO, '.taskcluster.yml')
 
             with open(template, 'r') as f:
                 taskcluster_yml = yaml.safe_load(f)
@@ -198,14 +205,14 @@ def register_callback_action(name, title, symbol, description, order=10000,
                     '$let': {
                         'tasks_for': 'action',
                         'repository': {
-                            'url': parameters['head_repository'],
+                            'url': parameters[repo_param],
                             'project': parameters['project'],
                             'level': parameters['level'],
                         },
                         'push': {
                             'owner': 'mozilla-taskcluster-maintenance@mozilla.com',
                             'pushlog_id': parameters['pushlog_id'],
-                            'revision': parameters['head_rev'],
+                            'revision': revision,
                         },
                         'action': {
                             'name': name,
@@ -225,7 +232,7 @@ def register_callback_action(name, title, symbol, description, order=10000,
     return register_callback
 
 
-def render_actions_json(parameters):
+def render_actions_json(parameters, graph_config):
     """
     Render JSON object for the ``public/actions.json`` artifact.
 
@@ -241,8 +248,8 @@ def render_actions_json(parameters):
     """
     assert isinstance(parameters, Parameters), 'requires instance of Parameters'
     result = []
-    for action in sorted(get_actions(), key=lambda action: action.order):
-        task = action.task_template_builder(parameters)
+    for action in sorted(_get_actions(graph_config), key=lambda action: action.order):
+        task = action.task_template_builder(parameters, graph_config)
         if task:
             assert is_json(task), 'task must be a JSON compatible object'
             res = {
@@ -266,26 +273,27 @@ def render_actions_json(parameters):
     }
 
 
-def trigger_action_callback(task_group_id, task_id, task, input, callback, parameters,
+def trigger_action_callback(task_group_id, task_id, task, input, callback, parameters, root,
                             test=False):
     """
     Trigger action callback with the given inputs. If `test` is true, then run
     the action callback in testing mode, without actually creating tasks.
     """
-    cb = get_callbacks().get(callback, None)
+    graph_config = load_graph_config(root)
+    callbacks = _get_callbacks(graph_config)
+    cb = callbacks.get(callback, None)
     if not cb:
         raise Exception('Unknown callback: {}. Known callbacks: {}'.format(
-            callback, get_callbacks().keys()))
+            callback, callbacks))
 
     if test:
         create.testing = True
         taskcluster.testing = True
 
-    cb(Parameters(**parameters), input, task_group_id, task_id, task)
+    cb(Parameters(**parameters), graph_config, input, task_group_id, task_id, task)
 
 
-@memoize
-def _load():
+def _load(graph_config):
     # Load all modules from this folder, relying on the side-effects of register_
     # functions to populate the action registry.
     actions_dir = os.path.dirname(__file__)
@@ -295,13 +303,13 @@ def _load():
         if f.endswith('.yml'):
             with open(os.path.join(actions_dir, f), 'r') as d:
                 frontmatter, template = yaml.safe_load_all(d)
-                register_task_action(**frontmatter)(lambda _: template)
+                register_task_action(**frontmatter)(lambda _p, _g: template)
     return callbacks, actions
 
 
-def get_callbacks():
-    return _load()[0]
+def _get_callbacks(graph_config):
+    return _load(graph_config)[0]
 
 
-def get_actions():
-    return _load()[1]
+def _get_actions(graph_config):
+    return _load(graph_config)[1]
diff --git a/taskcluster/taskgraph/actions/release_promotion.py b/taskcluster/taskgraph/actions/release_promotion.py
index c73c75f0aba0..388327efb533 100644
--- a/taskcluster/taskgraph/actions/release_promotion.py
+++ b/taskcluster/taskgraph/actions/release_promotion.py
@@ -212,7 +212,7 @@ def is_release_promotion_available(parameters):
         "required": ['release_promotion_flavor', 'build_number'],
     }
 )
-def release_promotion_action(parameters, input, task_group_id, task_id, task):
+def release_promotion_action(parameters, graph_config, input, task_group_id, task_id, task):
     release_promotion_flavor = input['release_promotion_flavor']
     promotion_config = RELEASE_PROMOTION_CONFIG[release_promotion_flavor]
     release_history = {}
@@ -262,8 +262,8 @@ def release_promotion_action(parameters, input, task_group_id, task_id, task):
     if not previous_graph_ids:
         revision = input.get('revision')
         parameters['pushlog_id'] = parameters['pushlog_id'] or \
-            find_hg_revision_pushlog_id(parameters, revision)
-        previous_graph_ids = [find_decision_task(parameters)]
+            find_hg_revision_pushlog_id(parameters, graph_config, revision)
+        previous_graph_ids = [find_decision_task(parameters, graph_config)]
 
     # Download parameters from the first decision task
     parameters = get_artifact(previous_graph_ids[0], "public/parameters.yml")
diff --git a/taskcluster/taskgraph/actions/rerun.py b/taskcluster/taskgraph/actions/rerun.py
index aa025e24782a..27029585cad1 100644
--- a/taskcluster/taskgraph/actions/rerun.py
+++ b/taskcluster/taskgraph/actions/rerun.py
@@ -37,9 +37,10 @@ RERUN_STATES = ('exception', 'failed')
         'properties': {}
     }
 )
-def rerun_action(parameters, input, task_group_id, task_id, task):
+def rerun_action(parameters, graph_config, input, task_group_id, task_id, task):
     parameters = dict(parameters)
-    decision_task_id, full_task_graph, label_to_taskid = fetch_graph_and_labels(parameters)
+    decision_task_id, full_task_graph, label_to_taskid = fetch_graph_and_labels(
+        parameters, graph_config)
     label = task['metadata']['name']
     if task_id not in label_to_taskid.values():
         logger.error(
diff --git a/taskcluster/taskgraph/actions/retrigger.py b/taskcluster/taskgraph/actions/retrigger.py
index 1576e6f786a2..a547372628e2 100644
--- a/taskcluster/taskgraph/actions/retrigger.py
+++ b/taskcluster/taskgraph/actions/retrigger.py
@@ -48,8 +48,9 @@ logger = logging.getLogger(__name__)
         }
     }
 )
-def retrigger_action(parameters, input, task_group_id, task_id, task):
-    decision_task_id, full_task_graph, label_to_taskid = fetch_graph_and_labels(parameters)
+def retrigger_action(parameters, graph_config, input, task_group_id, task_id, task):
+    decision_task_id, full_task_graph, label_to_taskid = fetch_graph_and_labels(
+        parameters, graph_config)
 
     label = task['metadata']['name']
     with_downstream = ' '
diff --git a/taskcluster/taskgraph/actions/run_missing_tests.py b/taskcluster/taskgraph/actions/run_missing_tests.py
index 658e1ebad807..49c050e024cc 100644
--- a/taskcluster/taskgraph/actions/run_missing_tests.py
+++ b/taskcluster/taskgraph/actions/run_missing_tests.py
@@ -28,8 +28,9 @@ logger = logging.getLogger(__name__)
     order=100,  # Useful for sheriffs, but not top of the list
     context=[],  # Applies to decision task
 )
-def run_missing_tests(parameters, input, task_group_id, task_id, task):
-    decision_task_id, full_task_graph, label_to_taskid = fetch_graph_and_labels(parameters)
+def run_missing_tests(parameters, graph_config, input, task_group_id, task_id, task):
+    decision_task_id, full_task_graph, label_to_taskid = fetch_graph_and_labels(
+        parameters, graph_config)
     target_tasks = get_artifact(decision_task_id, "public/target-tasks.json")
 
     # The idea here is to schedule all tasks of the `test` kind that were
diff --git a/taskcluster/taskgraph/actions/util.py b/taskcluster/taskgraph/actions/util.py
index 081c22137390..78af1667b041 100644
--- a/taskcluster/taskgraph/actions/util.py
+++ b/taskcluster/taskgraph/actions/util.py
@@ -24,18 +24,21 @@ logger = logging.getLogger(__name__)
 PUSHLOG_TMPL = '{}/json-pushes?version=2&changeset={}&tipsonly=1&full=1'
 
 
-def find_decision_task(parameters):
+def find_decision_task(parameters, graph_config):
     """Given the parameters for this action, find the taskId of the decision
     task"""
-    return find_task_id('gecko.v2.{}.pushlog-id.{}.decision'.format(
+    return find_task_id('{}.v2.{}.pushlog-id.{}.decision'.format(
+        graph_config['trust-domain'],
         parameters['project'],
         parameters['pushlog_id']))
 
 
-def find_hg_revision_pushlog_id(parameters, revision):
+def find_hg_revision_pushlog_id(parameters, graph_config, revision):
     """Given the parameters for this action and a revision, find the
     pushlog_id of the revision."""
-    pushlog_url = PUSHLOG_TMPL.format(parameters['head_repository'], revision)
+
+    repo_param = '{}head_repository'.format(graph_config['project-repo-param-prefix'])
+    pushlog_url = PUSHLOG_TMPL.format(parameters[repo_param], revision)
     r = requests.get(pushlog_url)
     r.raise_for_status()
     pushes = r.json()['pushes'].keys()
@@ -63,8 +66,8 @@ def find_existing_tasks_from_previous_kinds(full_task_graph, previous_graph_ids,
     return existing_tasks
 
 
-def fetch_graph_and_labels(parameters):
-    decision_task_id = find_decision_task(parameters)
+def fetch_graph_and_labels(parameters, graph_config):
+    decision_task_id = find_decision_task(parameters, graph_config)
 
     # First grab the graph and labels generated during the initial decision task
     full_task_graph = get_artifact(decision_task_id, "public/full-task-graph.json")
@@ -73,7 +76,8 @@ def fetch_graph_and_labels(parameters):
 
     # Now fetch any modifications made by action tasks and swap out new tasks
     # for old ones
-    namespace = 'gecko.v2.{}.pushlog-id.{}.actions'.format(
+    namespace = '{}.v2.{}.pushlog-id.{}.actions'.format(
+        graph_config['trust-domain'],
         parameters['project'],
         parameters['pushlog_id'])
     for action in list_tasks(namespace):
diff --git a/taskcluster/taskgraph/config.py b/taskcluster/taskgraph/config.py
index 34641a0a051c..d7b1a5417280 100644
--- a/taskcluster/taskgraph/config.py
+++ b/taskcluster/taskgraph/config.py
@@ -11,12 +11,16 @@ graph_config_schema = Schema({
     # The trust-domain for this graph.
     # (See https://firefox-source-docs.mozilla.org/taskcluster/taskcluster/taskgraph.html#taskgraph-trust-domain)  # noqa
     Required('trust-domain'): basestring,
+    # This specifes the prefix for repo parameters that refer to the project being built.
+    # This selects between `head_rev` and `comm_head_rev` and related paramters.
+    # (See http://firefox-source-docs.mozilla.org/taskcluster/taskcluster/parameters.html#push-information  # noqa
+    # and http://firefox-source-docs.mozilla.org/taskcluster/taskcluster/parameters.html#comm-push-information)  # noqa
+    Required('project-repo-param-prefix'): basestring,
     Required('treeherder'): {
         # Mapping of treeherder group symbols to descriptive names
         Required('group-names'): {basestring: basestring}
     },
     Required('index'): {
-
         Required('products'): [basestring],
     },
     Required('try'): {
diff --git a/taskcluster/taskgraph/decision.py b/taskcluster/taskgraph/decision.py
index 71fcafa31b4e..c1d42b127906 100644
--- a/taskcluster/taskgraph/decision.py
+++ b/taskcluster/taskgraph/decision.py
@@ -131,7 +131,7 @@ def taskgraph_decision(options, parameters=None):
     write_artifact('parameters.yml', dict(**parameters))
 
     # write out the public/actions.json file
-    write_artifact('actions.json', render_actions_json(parameters))
+    write_artifact('actions.json', render_actions_json(parameters, tgg.graph_config))
 
     # write out the full graph for reference
     full_task_json = tgg.full_task_graph.to_json()
diff --git a/taskcluster/taskgraph/generator.py b/taskcluster/taskgraph/generator.py
index fa4d921442fd..1055710535ed 100644
--- a/taskcluster/taskgraph/generator.py
+++ b/taskcluster/taskgraph/generator.py
@@ -213,6 +213,15 @@ class TaskGraphGenerator(object):
         """
         return self._run_until('morphed_task_graph')
 
+    @property
+    def graph_config(self):
+        """
+        The configuration for this graph.
+
+        @type: TaskGraph
+        """
+        return self._run_until('graph_config')
+
     def _load_kinds(self, graph_config):
         for kind_name in os.listdir(self.root_dir):
             try:
@@ -224,6 +233,8 @@ class TaskGraphGenerator(object):
         logger.info("Loading graph configuration.")
         graph_config = load_graph_config(self.root_dir)
 
+        yield verifications('graph_config', graph_config)
+
         logger.info("Loading kinds")
         # put the kinds into a graph and sort topologically so that kinds are loaded
         # in post-order
diff --git a/taskcluster/taskgraph/target_tasks.py b/taskcluster/taskgraph/target_tasks.py
index b9242285508f..ad1a83e518af 100644
--- a/taskcluster/taskgraph/target_tasks.py
+++ b/taskcluster/taskgraph/target_tasks.py
@@ -619,5 +619,5 @@ def target_tasks_file_update(full_task_graph, parameters, graph_config):
     """
     def filter(task):
         # For now any task in the repo-update kind is ok
-        return task.kind in ['repo-update', 'repo-update-bb']
+        return task.kind in ['repo-update']
     return [l for l, t in full_task_graph.tasks.iteritems() if filter(t)]
diff --git a/taskcluster/taskgraph/transforms/task.py b/taskcluster/taskgraph/transforms/task.py
index 8996bf528dc1..1d9d0f9fc830 100644
--- a/taskcluster/taskgraph/transforms/task.py
+++ b/taskcluster/taskgraph/transforms/task.py
@@ -614,25 +614,9 @@ V2_L10N_TEMPLATES = [
 # the roots of the treeherder routes
 TREEHERDER_ROUTE_ROOT = 'tc-treeherder'
 
-# Which repository repository revision to use when reporting results to treeherder.
-DEFAULT_BRANCH_REV_PARAM = 'head_rev'
-BRANCH_REV_PARAM = {
-    'comm-esr45': 'comm_head_rev',
-    'comm-esr52': 'comm_head_rev',
-    'comm-beta': 'comm_head_rev',
-    'comm-central': 'comm_head_rev',
-    'comm-aurora': 'comm_head_rev',
-    'try-comm-central': 'comm_head_rev',
-}
-
 
 def get_branch_rev(config):
-    return config.params[
-        BRANCH_REV_PARAM.get(
-            config.params['project'],
-            DEFAULT_BRANCH_REV_PARAM
-        )
-    ]
+    return config.params['{}head_rev'.format(config.graph_config['project-repo-param-prefix'])]
 
 
 COALESCE_KEY = '{project}.{job-identifier}'
@@ -1549,7 +1533,7 @@ def build_task(config, tasks):
             )
 
         if 'expires-after' not in task:
-            task['expires-after'] = '28 days' if config.params['project'] == 'try' else '1 year'
+            task['expires-after'] = '28 days' if config.params.is_try() else '1 year'
 
         if 'deadline-after' not in task:
             task['deadline-after'] = '1 day'
diff --git a/taskcluster/taskgraph/transforms/tests.py b/taskcluster/taskgraph/transforms/tests.py
index cc5521a981be..8a83d443299e 100644
--- a/taskcluster/taskgraph/transforms/tests.py
+++ b/taskcluster/taskgraph/transforms/tests.py
@@ -491,7 +491,7 @@ def setup_talos(config, tests):
 
         # Per https://bugzilla.mozilla.org/show_bug.cgi?id=1357753#c3, branch
         # name is only required for try
-        if config.params['project'] == 'try':
+        if config.params.is_try():
             extra_options.append('--branch-name')
             extra_options.append('try')
 
@@ -596,7 +596,7 @@ def set_expires_after(config, tests):
     keep storage costs low."""
     for test in tests:
         if 'expires-after' not in test:
-            if config.params['project'] == 'try':
+            if config.params.is_try():
                 test['expires-after'] = "14 days"
             else:
                 test['expires-after'] = "1 year"
@@ -976,7 +976,7 @@ def make_job_description(config, tests):
             jobdesc['when'] = test['when']
         elif 'optimization' in test:
             jobdesc['optimization'] = test['optimization']
-        elif config.params['project'] != 'try' and suite not in INCLUSIVE_COMPONENTS:
+        elif not config.params.is_try() and suite not in INCLUSIVE_COMPONENTS:
             # for non-try branches and non-inclusive suites, include SETA
             jobdesc['optimization'] = {'skip-unless-schedules-or-seta': schedules}
         else:
diff --git a/toolkit/components/telemetry/Histograms.json b/toolkit/components/telemetry/Histograms.json
index a988c054bc32..7b9ecc33961f 100644
--- a/toolkit/components/telemetry/Histograms.json
+++ b/toolkit/components/telemetry/Histograms.json
@@ -2053,29 +2053,29 @@
   },
   "TLS_EARLY_DATA_NEGOTIATED": {
     "record_in_processes": ["main", "content"],
-    "expires_in_version": "62",
+    "expires_in_version": "66",
     "kind": "enumerated",
     "n_values": 3,
     "description": "Sending TLS early data was possible: 0 - not possible, 1 - possible but not used, 2 - possible and used.",
-    "alert_emails": ["necko@mozilla.com"],
+    "alert_emails": ["necko@mozilla.com", "ddamjanovic@mozilla.com"],
     "bug_numbers": [1296288]
   },
   "TLS_EARLY_DATA_ACCEPTED": {
     "record_in_processes": ["main", "content"],
-    "expires_in_version": "62",
+    "expires_in_version": "66",
     "kind": "boolean",
     "description": "TLS early data was used and it was accepted (true) or rejected (false) by the remote host.",
-    "alert_emails": ["necko@mozilla.com"],
+    "alert_emails": ["necko@mozilla.com", "ddamjanovic@mozilla.com"],
     "bug_numbers": [1296288]
   },
   "TLS_EARLY_DATA_BYTES_WRITTEN": {
     "record_in_processes": ["main", "content"],
-    "expires_in_version": "62",
+    "expires_in_version": "66",
     "kind": "exponential",
     "high": 60000,
     "n_buckets": 100,
     "description": "Amount of bytes sent using TLS early data at the start of a TLS connection for a given channel.",
-    "alert_emails": ["necko@mozilla.com"],
+    "alert_emails": ["necko@mozilla.com", "ddamjanovic@mozilla.com"],
     "bug_numbers": [1296288]
   },
   "SSL_HANDSHAKE_VERSION": {
diff --git a/toolkit/components/telemetry/TelemetrySession.jsm b/toolkit/components/telemetry/TelemetrySession.jsm
index 2d3f48c49518..b030fa4af34b 100644
--- a/toolkit/components/telemetry/TelemetrySession.jsm
+++ b/toolkit/components/telemetry/TelemetrySession.jsm
@@ -767,8 +767,6 @@ var Impl = {
 
     ret.startupInterrupted = Number(Services.startup.interrupted);
 
-    ret.js = Cu.getJSEngineTelemetryValue();
-
     let maximalNumberOfConcurrentThreads = Telemetry.maximalNumberOfConcurrentThreads;
     if (maximalNumberOfConcurrentThreads) {
       ret.maximalNumberOfConcurrentThreads = maximalNumberOfConcurrentThreads;
diff --git a/toolkit/components/telemetry/docs/data/main-ping.rst b/toolkit/components/telemetry/docs/data/main-ping.rst
index 9fcabda12f70..c4e7d17fc1a9 100644
--- a/toolkit/components/telemetry/docs/data/main-ping.rst
+++ b/toolkit/components/telemetry/docs/data/main-ping.rst
@@ -184,7 +184,7 @@ Structure:
       // ...
     }
 
-As of Firefox 59 this section no longer contains any entries.
+As of Firefox 59 this section no longer contains any entries, as of Firefox 61 this section is removed.
 
 maximalNumberOfConcurrentThreads
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -697,4 +697,5 @@ Version History
 
   - Stopped reporting ``childPayloads`` (`bug 1443599 <https://bugzilla.mozilla.org/show_bug.cgi?id=1443599>`_).
   - Stopped reporting ``saved-session`` pings on Firefox Desktop (`bug 1443603 <https://bugzilla.mozilla.org/show_bug.cgi?id=1443603>`_).
+  - Stopped reporting ``simpleMeasurements.js`` (`bug 1278920 <https://bugzilla.mozilla.org/show_bug.cgi?id=1278920>`_).
   - Stopped reporting ``UITelemetry`` (`bug 1443605 <https://bugzilla.mozilla.org/show_bug.cgi?id=1443605>`_)
diff --git a/toolkit/xre/nsAppRunner.cpp b/toolkit/xre/nsAppRunner.cpp
index d442334e0c16..327f27523e7d 100644
--- a/toolkit/xre/nsAppRunner.cpp
+++ b/toolkit/xre/nsAppRunner.cpp
@@ -1716,8 +1716,8 @@ DumpHelp()
          "  --new-instance     Open new instance, not a new window in running instance.\n"
          "  --UILocale <locale> Start with <locale> resources as UI Locale.\n"
          "  --safe-mode        Disables extensions and themes for this session.\n"
-         "  -MOZ_LOG <modules> Treated as MOZ_LOG=<modules> environment variable, overrides it.\n"
-         "  -MOZ_LOG_FILE <file> Treated as MOZ_LOG_FILE=<file> environment variable, overrides it.\n"
+         "  -MOZ_LOG=<modules> Treated as MOZ_LOG=<modules> environment variable, overrides it.\n"
+         "  -MOZ_LOG_FILE=<file> Treated as MOZ_LOG_FILE=<file> environment variable, overrides it.\n"
          "                     If MOZ_LOG_FILE is not specified as an argument or as an environment variable,\n"
          "                     logging will be written to stdout.\n"
          , (const char*)gAppData->name);
diff --git a/widget/android/nsLookAndFeel.cpp b/widget/android/nsLookAndFeel.cpp
index 09c31e960772..c3877bcc480e 100644
--- a/widget/android/nsLookAndFeel.cpp
+++ b/widget/android/nsLookAndFeel.cpp
@@ -9,6 +9,7 @@
 #include "nsLookAndFeel.h"
 #include "gfxFont.h"
 #include "gfxFontConstants.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/gfx/2D.h"
 
 using namespace mozilla;
@@ -466,7 +467,7 @@ nsLookAndFeel::GetFontImpl(FontID aID, nsString& aFontName,
 {
     aFontName.AssignLiteral("\"Roboto\"");
     aFontStyle.style = NS_FONT_STYLE_NORMAL;
-    aFontStyle.weight = NS_FONT_WEIGHT_NORMAL;
+    aFontStyle.weight = FontWeight::Normal();
     aFontStyle.stretch = NS_FONT_STRETCH_NORMAL;
     aFontStyle.size = 9.0 * 96.0f / 72.0f * aDevPixPerCSSPixel;
     aFontStyle.systemFont = true;
diff --git a/widget/cocoa/nsLookAndFeel.mm b/widget/cocoa/nsLookAndFeel.mm
index c2cb595f366a..b8b022b778f5 100644
--- a/widget/cocoa/nsLookAndFeel.mm
+++ b/widget/cocoa/nsLookAndFeel.mm
@@ -13,6 +13,7 @@
 #include "gfxFont.h"
 #include "gfxFontConstants.h"
 #include "gfxPlatformMac.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/gfx/2D.h"
 #include "mozilla/widget/WidgetMessageUtils.h"
 
@@ -565,7 +566,7 @@ nsLookAndFeel::GetFontImpl(FontID aID, nsString &aFontName,
     // hack for now
     if (aID == eFont_Window || aID == eFont_Document) {
         aFontStyle.style      = NS_FONT_STYLE_NORMAL;
-        aFontStyle.weight     = NS_FONT_WEIGHT_NORMAL;
+        aFontStyle.weight     = mozilla::FontWeight::Normal();
         aFontStyle.stretch    = NS_FONT_STRETCH_NORMAL;
         aFontStyle.size       = 14 * aDevPixPerCSSPixel;
         aFontStyle.systemFont = true;
diff --git a/widget/gtk/nsLookAndFeel.cpp b/widget/gtk/nsLookAndFeel.cpp
index 696ab419ad1d..ea3d0db3da09 100644
--- a/widget/gtk/nsLookAndFeel.cpp
+++ b/widget/gtk/nsLookAndFeel.cpp
@@ -18,6 +18,7 @@
 
 #include <fontconfig/fontconfig.h>
 #include "gfxPlatformGtk.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "ScreenHelperGTK.h"
 
 #include "gtkdrawing.h"
@@ -722,7 +723,8 @@ GetSystemFontInfo(GtkStyleContext *aStyle,
     NS_ConvertUTF8toUTF16 family(pango_font_description_get_family(desc));
     *aFontName = quote + family + quote;
 
-    aFontStyle->weight = pango_font_description_get_weight(desc);
+    aFontStyle->weight =
+        mozilla::FontWeight(pango_font_description_get_weight(desc));
 
     // FIXME: Set aFontStyle->stretch correctly!
     aFontStyle->stretch = NS_FONT_STRETCH_NORMAL;
diff --git a/widget/headless/HeadlessLookAndFeelGTK.cpp b/widget/headless/HeadlessLookAndFeelGTK.cpp
index ab9c8418fe6a..90744e5aee82 100644
--- a/widget/headless/HeadlessLookAndFeelGTK.cpp
+++ b/widget/headless/HeadlessLookAndFeelGTK.cpp
@@ -5,6 +5,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "HeadlessLookAndFeel.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "nsIContent.h"
 
 using mozilla::LookAndFeel;
@@ -337,7 +338,7 @@ HeadlessLookAndFeel::GetFontImpl(FontID aID, nsString& aFontName,
 {
   // Default to san-serif for everything.
   aFontStyle.style      = NS_FONT_STYLE_NORMAL;
-  aFontStyle.weight     = NS_FONT_WEIGHT_NORMAL;
+  aFontStyle.weight     = FontWeight::Normal();
   aFontStyle.stretch    = NS_FONT_STRETCH_NORMAL;
   aFontStyle.size       = 14 * aDevPixPerCSSPixel;
   aFontStyle.systemFont = true;
diff --git a/widget/uikit/nsLookAndFeel.mm b/widget/uikit/nsLookAndFeel.mm
index b26e961b3093..437c808c6d29 100644
--- a/widget/uikit/nsLookAndFeel.mm
+++ b/widget/uikit/nsLookAndFeel.mm
@@ -7,6 +7,8 @@
 #import <UIKit/UIInterface.h>
 
 #include "nsLookAndFeel.h"
+
+#include "mozilla/FontPropertyTypes.h"
 #include "nsStyleConsts.h"
 #include "gfxFont.h"
 #include "gfxFontConstants.h"
@@ -400,7 +402,7 @@ nsLookAndFeel::GetFontImpl(FontID aID, nsString &aFontName,
     // hack for now
     if (aID == eFont_Window || aID == eFont_Document) {
         aFontStyle.style      = NS_FONT_STYLE_NORMAL;
-        aFontStyle.weight     = NS_FONT_WEIGHT_NORMAL;
+        aFontStyle.weight     = FontWeight::Normal();
         aFontStyle.stretch    = NS_FONT_STRETCH_NORMAL;
         aFontStyle.size       = 14 * aDevPixPerCSSPixel;
         aFontStyle.systemFont = true;
diff --git a/widget/windows/nsLookAndFeel.cpp b/widget/windows/nsLookAndFeel.cpp
index 9ca99ccfbee2..2bba91978aa4 100755
--- a/widget/windows/nsLookAndFeel.cpp
+++ b/widget/windows/nsLookAndFeel.cpp
@@ -10,6 +10,7 @@
 #include "nsUXThemeData.h"
 #include "nsUXThemeConstants.h"
 #include "WinUtils.h"
+#include "mozilla/FontPropertyTypes.h"
 #include "mozilla/Telemetry.h"
 #include "mozilla/WindowsVersion.h"
 #include "gfxFontConstants.h"
@@ -707,7 +708,7 @@ GetSysFontInfo(HDC aHDC, LookAndFeel::FontID anID,
   // FIXME: Other weights?
   aFontStyle.weight =
     (ptrLogFont->lfWeight == FW_BOLD ?
-        NS_FONT_WEIGHT_BOLD : NS_FONT_WEIGHT_NORMAL);
+        FontWeight::Bold() : FontWeight::Normal());
 
   // FIXME: Set aFontStyle->stretch correctly!
   aFontStyle.stretch = NS_FONT_STRETCH_NORMAL;
diff --git a/xpcom/base/LogCommandLineHandler.cpp b/xpcom/base/LogCommandLineHandler.cpp
new file mode 100644
index 000000000000..73b5b82ae7c6
--- /dev/null
+++ b/xpcom/base/LogCommandLineHandler.cpp
@@ -0,0 +1,91 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+* License, v. 2.0. If a copy of the MPL was not distributed with this
+* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "LogCommandLineHandler.h"
+
+#include "mozilla/Tokenizer.h"
+#include "nsDebug.h"
+
+namespace mozilla {
+
+void LoggingHandleCommandLineArgs(int argc, char const* const* argv,
+                                  std::function<void(nsACString const&)> const& consumer)
+{
+  // Keeps the name of a pending env var (MOZ_LOG or MOZ_LOG_FILE) that
+  // we expect to get a value for in the next iterated arg.
+  // Used for the `-MOZ_LOG <modules>` form of argument.
+  nsAutoCString env;
+
+  auto const names = {
+    NS_LITERAL_CSTRING("MOZ_LOG"),
+    NS_LITERAL_CSTRING("MOZ_LOG_FILE")
+  };
+
+  for (int arg = 1; arg < argc; ++arg) {
+    Tokenizer p(argv[arg]);
+
+    if (!env.IsEmpty() && p.CheckChar('-')) {
+      NS_WARNING("Expects value after -MOZ_LOG(_FILE) argument, but another argument found");
+
+      // We only expect values for the pending env var, start over
+      p.Rollback();
+      env.Truncate();
+    }
+
+    if (env.IsEmpty()) {
+      if (!p.CheckChar('-')) {
+        continue;
+      }
+      // We accept `-MOZ_LOG` as well as `--MOZ_LOG`.
+      Unused << p.CheckChar('-');
+
+      for (auto const& name : names) {
+        if (!p.CheckWord(name)) {
+          continue;
+        }
+
+        env.Assign(name);
+        env.Append('=');
+        break;
+      }
+
+      if (env.IsEmpty()) {
+        // An unknonwn argument, ignore.
+        continue;
+      }
+
+      // We accept `-MOZ_LOG <modules>` as well as `-MOZ_LOG=<modules>`.
+
+      if (p.CheckEOF()) {
+        // We have a lone `-MOZ_LOG` arg, the next arg is expected to be
+        // the value, |env| is now prepared as `MOZ_LOG=`.
+        continue;
+      }
+
+      if (!p.CheckChar('=')) {
+        // There is a character after the arg name and it's not '=',
+        // ignore this argument.
+        NS_WARNING("-MOZ_LOG(_FILE) argument not in a proper form");
+
+        env.Truncate();
+        continue;
+      }
+    }
+
+    // This can be non-empty from previous iteration or in this iteration.
+    if (!env.IsEmpty()) {
+      nsDependentCSubstring value;
+      Unused << p.ReadUntil(Tokenizer::Token::EndOfFile(), value);
+      env.Append(value);
+
+      consumer(env);
+
+      env.Truncate();
+    }
+  }
+}
+
+} // mozilla
\ No newline at end of file
diff --git a/xpcom/base/LogCommandLineHandler.h b/xpcom/base/LogCommandLineHandler.h
new file mode 100644
index 000000000000..ebc774b71ba1
--- /dev/null
+++ b/xpcom/base/LogCommandLineHandler.h
@@ -0,0 +1,49 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+* License, v. 2.0. If a copy of the MPL was not distributed with this
+* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef LogCommandLineHandler_h
+#define LogCommandLineHandler_h
+
+#include <functional>
+#include "nsString.h"
+
+namespace mozilla {
+
+/**
+ * A helper function parsing provided command line arguments and handling two
+ * specific args:
+ *
+ * -MOZ_LOG=modulelist
+ * -MOZ_LOG_FILE=file/path
+ *
+ * both expecting an argument, and corresponding to the same-name environment
+ * variables we use for logging setup.
+ *
+ * When an argument is found in the proper form, the consumer callback is called
+ * with a string in a follwing form, note that we do this for every occurence,
+ * and not just at the end of the parsing:
+ *
+ * "MOZ_LOG=modulelist" or "MOZ_LOG_FILE=file/path"
+ *
+ * All the following forms of arguments of the application are possible:
+ *
+ * --MOZ_LOG modulelist
+ * -MOZ_LOG modulelist
+ * --MOZ_LOG=modulelist
+ * -MOZ_LOG=modulelist
+ *
+ * The motivation for a separte function and not implementing a command line
+ * handler interface is that we need to process this very early during the
+ * application startup.  Command line handlers are proccessed way later
+ * after logging has already been set up.
+ */
+void
+LoggingHandleCommandLineArgs(int argc, char const* const* argv,
+                             std::function<void(nsACString const&)> const& consumer);
+
+} // mozilla
+
+#endif
diff --git a/xpcom/base/Logging.cpp b/xpcom/base/Logging.cpp
index d9f46b53a44f..14de8ab83df7 100644
--- a/xpcom/base/Logging.cpp
+++ b/xpcom/base/Logging.cpp
@@ -20,6 +20,7 @@
 #include "nsClassHashtable.h"
 #include "nsDebug.h"
 #include "NSPRLogModulesParser.h"
+#include "LogCommandLineHandler.h"
 
 #include "prenv.h"
 #ifdef XP_WIN
@@ -191,39 +192,6 @@ public:
     delete logFile;
   }
 
-  void HandleCommandLineArgs(int argc, char* argv[])
-  {
-    for (int arg = 2; arg < argc; ++arg) {
-      if (argv[arg][0] == '-') {
-        continue;
-      }
-
-      for (auto name : {"-MOZ_LOG", "-MOZ_LOG_FILE"}) {
-        if (strcmp(name, argv[arg - 1])) {
-          continue;
-        }
-
-        // We deliberately set/rewrite the environment variables
-        // so that when child processes are spawned w/o passing
-        // the arguments they still inherit the logging settings
-        // as well as sandboxing can be correctly set.
-        // Scripts can pass -MOZ_LOG=$MOZ_LOG,modules as an argument
-        // to merge existing settings, if required.
-
-        nsAutoCString env;
-        env.Assign(name + 1);
-        env.Append('=');
-        env.Append(argv[arg]);
-
-        // PR_SetEnv takes ownership of the string.
-        PR_SetEnv(ToNewCString(env));
-
-        ++arg;
-        break;
-      }
-    }
-  }
-
   /**
    * Loads config from command line args or env vars if present, in
    * this specific order of priority.
@@ -238,7 +206,18 @@ public:
     MOZ_DIAGNOSTIC_ASSERT(!mInitialized);
     mInitialized = true;
 
-    HandleCommandLineArgs(argc, argv);
+    LoggingHandleCommandLineArgs(argc, static_cast<char const* const*>(argv),
+                                 [](nsACString const& env) {
+      // We deliberately set/rewrite the environment variables
+      // so that when child processes are spawned w/o passing
+      // the arguments they still inherit the logging settings
+      // as well as sandboxing can be correctly set.
+      // Scripts can pass -MOZ_LOG=$MOZ_LOG,modules as an argument
+      // to merge existing settings, if required.
+
+      // PR_SetEnv takes ownership of the string.
+      PR_SetEnv(ToNewCString(env));
+    });
 
     bool shouldAppend = false;
     bool addTimestamp = false;
diff --git a/xpcom/base/Logging.h b/xpcom/base/Logging.h
index 60fe699c438f..ef03960c2f99 100644
--- a/xpcom/base/Logging.h
+++ b/xpcom/base/Logging.h
@@ -191,7 +191,6 @@ void log_print(const LogModule* aModule,
 
 } // namespace mozilla
 
-
 // Helper macro used convert MOZ_LOG's third parameter, |_args|, from a
 // parenthesized form to a varargs form. For example:
 //   ("%s", "a message") => "%s", "a message"
diff --git a/xpcom/base/moz.build b/xpcom/base/moz.build
index 8774354a7a4e..55015b077477 100644
--- a/xpcom/base/moz.build
+++ b/xpcom/base/moz.build
@@ -139,6 +139,7 @@ UNIFIED_SOURCES += [
     'ErrorNames.cpp',
     'HoldDropJSObjects.cpp',
     'JSObjectHolder.cpp',
+    'LogCommandLineHandler.cpp',
     'Logging.cpp',
     'LogModulePrefWatcher.cpp',
     'nsClassInfoImpl.cpp',
diff --git a/xpcom/io/SlicedInputStream.cpp b/xpcom/io/SlicedInputStream.cpp
index b2e2ba522204..23acf8decae3 100644
--- a/xpcom/io/SlicedInputStream.cpp
+++ b/xpcom/io/SlicedInputStream.cpp
@@ -6,6 +6,7 @@
 
 #include "SlicedInputStream.h"
 #include "mozilla/ipc/InputStreamUtils.h"
+#include "mozilla/ScopeExit.h"
 #include "nsISeekableStream.h"
 #include "nsStreamUtils.h"
 
@@ -274,40 +275,42 @@ SlicedInputStream::AsyncWait(nsIInputStreamCallback* aCallback,
 
   nsCOMPtr<nsIInputStreamCallback> callback = aCallback ? this : nullptr;
 
-  MutexAutoLock lock(mMutex);
+  uint32_t flags = aFlags;
+  uint32_t requestedCount = aRequestedCount;
 
-  if (mAsyncWaitCallback && aCallback) {
-    return NS_ERROR_FAILURE;
-  }
+  {
+    MutexAutoLock lock(mMutex);
 
-  mAsyncWaitCallback = aCallback;
-
-  // If we haven't started retrieving data, let's see if we can seek.
-  // If we cannot seek, we will do consecutive reads.
-  if (mCurPos < mStart && mWeakSeekableInputStream) {
-    nsresult rv =
-      mWeakSeekableInputStream->Seek(nsISeekableStream::NS_SEEK_SET, mStart);
-    if (NS_WARN_IF(NS_FAILED(rv))) {
-      return rv;
+    if (mAsyncWaitCallback && aCallback) {
+      return NS_ERROR_FAILURE;
     }
 
-    mCurPos = mStart;
+    mAsyncWaitCallback = aCallback;
+
+    // If we haven't started retrieving data, let's see if we can seek.
+    // If we cannot seek, we will do consecutive reads.
+    if (mCurPos < mStart && mWeakSeekableInputStream) {
+      nsresult rv =
+        mWeakSeekableInputStream->Seek(nsISeekableStream::NS_SEEK_SET, mStart);
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        return rv;
+      }
+
+      mCurPos = mStart;
+    }
+
+    mAsyncWaitFlags = aFlags;
+    mAsyncWaitRequestedCount = aRequestedCount;
+    mAsyncWaitEventTarget = aEventTarget;
+
+    // If we are not at the right position, let's do an asyncWait just internal.
+    if (mCurPos < mStart) {
+      flags = 0;
+      requestedCount = mStart - mCurPos;
+    }
   }
 
-  mAsyncWaitFlags = aFlags;
-  mAsyncWaitRequestedCount = aRequestedCount;
-  mAsyncWaitEventTarget = aEventTarget;
-
-  // If we are not at the right position, let's do an asyncWait just internal.
-  if (mCurPos < mStart) {
-    uint64_t diff = mStart - mCurPos;
-
-    MutexAutoUnlock unlock(mMutex);
-    return mWeakAsyncInputStream->AsyncWait(callback, 0, diff, aEventTarget);
-  }
-
-  MutexAutoUnlock unlock(mMutex);
-  return mWeakAsyncInputStream->AsyncWait(callback, aFlags, aRequestedCount,
+  return mWeakAsyncInputStream->AsyncWait(callback, flags, requestedCount,
                                           aEventTarget);
 }
 
@@ -320,63 +323,77 @@ SlicedInputStream::OnInputStreamReady(nsIAsyncInputStream* aStream)
   MOZ_ASSERT(mWeakAsyncInputStream);
   MOZ_ASSERT(mWeakAsyncInputStream == aStream);
 
-  MutexAutoLock lock(mMutex);
+  nsCOMPtr<nsIInputStreamCallback> callback;
+  uint32_t asyncWaitFlags = 0;
+  uint32_t asyncWaitRequestedCount = 0;
+  nsCOMPtr<nsIEventTarget> asyncWaitEventTarget;
 
-  // We have been canceled in the meanwhile.
-  if (!mAsyncWaitCallback) {
-    return NS_OK;
-  }
+  {
+    MutexAutoLock lock(mMutex);
 
-  if (mCurPos < mStart) {
-    char buf[4096];
-    while (mCurPos < mStart) {
-      uint32_t bytesRead;
-      uint64_t bufCount = XPCOM_MIN(mStart - mCurPos, (uint64_t)sizeof(buf));
-      nsresult rv = mInputStream->Read(buf, bufCount, &bytesRead);
-      if (NS_SUCCEEDED(rv) && bytesRead == 0) {
-        mClosed = true;
-        return RunAsyncWaitCallback(lock);
-      }
-
-      if (rv == NS_BASE_STREAM_WOULD_BLOCK) {
-        uint64_t diff = mStart - mCurPos;
-        MutexAutoUnlock unlock(mMutex);
-        return mWeakAsyncInputStream->AsyncWait(this, 0, diff,
-                                                mAsyncWaitEventTarget);
-      }
-
-      if (NS_WARN_IF(NS_FAILED(rv))) {
-        return RunAsyncWaitCallback(lock);
-      }
-
-      mCurPos += bytesRead;
+    // We have been canceled in the meanwhile.
+    if (!mAsyncWaitCallback) {
+      return NS_OK;
     }
 
-    uint32_t asyncWaitFlags = mAsyncWaitFlags;
-    uint32_t asyncWaitRequestedCount = mAsyncWaitRequestedCount;
-    nsCOMPtr<nsIEventTarget> asyncWaitEventTarget = mAsyncWaitEventTarget;
+    auto raii = MakeScopeExit([&] {
+      mMutex.AssertCurrentThreadOwns();
+      mAsyncWaitCallback = nullptr;
+      mAsyncWaitEventTarget = nullptr;
+    });
 
-    MutexAutoUnlock unlock(mMutex);
+    asyncWaitFlags = mAsyncWaitFlags;
+    asyncWaitRequestedCount = mAsyncWaitRequestedCount;
+    asyncWaitEventTarget = mAsyncWaitEventTarget;
 
-    // Now we are ready to do the 'real' asyncWait.
-    return mWeakAsyncInputStream->AsyncWait(this, asyncWaitFlags,
-                                            asyncWaitRequestedCount,
-                                            asyncWaitEventTarget);
+    // If at the end of this locked block, the callback is not null, it will be
+    // executed, otherwise, we are going to exec another AsyncWait().
+    callback = mAsyncWaitCallback;
+
+    if (mCurPos < mStart) {
+      char buf[4096];
+      nsresult rv = NS_OK;
+      while (mCurPos < mStart) {
+        uint32_t bytesRead;
+        uint64_t bufCount = XPCOM_MIN(mStart - mCurPos, (uint64_t)sizeof(buf));
+        rv = mInputStream->Read(buf, bufCount, &bytesRead);
+        if (NS_SUCCEEDED(rv) && bytesRead == 0) {
+          mClosed = true;
+          break;
+        }
+
+        if (rv == NS_BASE_STREAM_WOULD_BLOCK) {
+          asyncWaitFlags = 0;
+          asyncWaitRequestedCount = mStart - mCurPos;
+          // Here we want to exec another AsyncWait().
+          callback = nullptr;
+          break;
+        }
+
+        if (NS_WARN_IF(NS_FAILED(rv))) {
+          break;
+        }
+
+        mCurPos += bytesRead;
+      }
+
+      // Now we are ready to do the 'real' asyncWait.
+      if (mCurPos >= mStart) {
+        // We don't want to nullify the callback now, because it will be needed
+        // at the next ::OnInputStreamReady.
+        raii.release();
+        callback = nullptr;
+      }
+    }
   }
 
-  return RunAsyncWaitCallback(lock);
-}
+  if (callback) {
+    return callback->OnInputStreamReady(this);
+  }
 
-nsresult
-SlicedInputStream::RunAsyncWaitCallback(const MutexAutoLock& aProofOfLock)
-{
-  nsCOMPtr<nsIInputStreamCallback> callback = mAsyncWaitCallback;
-
-  mAsyncWaitCallback = nullptr;
-  mAsyncWaitEventTarget = nullptr;
-
-  MutexAutoUnlock unlock(mMutex);
-  return callback->OnInputStreamReady(this);
+  return mWeakAsyncInputStream->AsyncWait(this, asyncWaitFlags,
+                                          asyncWaitRequestedCount,
+                                          asyncWaitEventTarget);
 }
 
 // nsIIPCSerializableInputStream
diff --git a/xpcom/io/SlicedInputStream.h b/xpcom/io/SlicedInputStream.h
index df48e488915e..a1bf63069410 100644
--- a/xpcom/io/SlicedInputStream.h
+++ b/xpcom/io/SlicedInputStream.h
@@ -57,9 +57,6 @@ private:
   void
   SetSourceStream(already_AddRefed<nsIInputStream> aInputStream);
 
-  nsresult
-  RunAsyncWaitCallback(const MutexAutoLock& aProofOfLock);
-
   nsCOMPtr<nsIInputStream> mInputStream;
 
   // Raw pointers because these are just QI of mInputStream.
diff --git a/xpcom/tests/gtest/TestLogCommandLineHandler.cpp b/xpcom/tests/gtest/TestLogCommandLineHandler.cpp
new file mode 100644
index 000000000000..be35c7cb3ee6
--- /dev/null
+++ b/xpcom/tests/gtest/TestLogCommandLineHandler.cpp
@@ -0,0 +1,182 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "LogCommandLineHandler.h"
+
+#include <iterator>
+#include "nsString.h"
+#include "nsTArray.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/UniquePtrExtensions.h"
+#include "plstr.h"
+#include "gtest/gtest.h"
+
+using namespace mozilla;
+
+template<class T, size_t N>
+constexpr size_t array_size(T (&)[N])
+{
+  return N;
+}
+
+TEST(LogCommandLineHandler, Empty)
+{
+  bool callbackInvoked = false;
+  auto callback = [&](nsACString const& env) mutable {
+    callbackInvoked = true;
+  };
+
+  mozilla::LoggingHandleCommandLineArgs(0, nullptr, callback);
+  EXPECT_FALSE(callbackInvoked);
+
+  char const* argv1[] = { "" };
+  mozilla::LoggingHandleCommandLineArgs(array_size(argv1), argv1, callback);
+  EXPECT_FALSE(callbackInvoked);
+}
+
+TEST(LogCommandLineHandler, MOZ_LOG_regular)
+{
+  nsTArray<nsCString> results;
+
+  auto callback = [&](nsACString const& env) mutable {
+    results.AppendElement(env);
+  };
+
+  char const* argv1[] = { "", "-MOZ_LOG", "module1:5,module2:4,sync,timestamp" };
+  results.Clear();
+  mozilla::LoggingHandleCommandLineArgs(array_size(argv1), argv1, callback);
+  EXPECT_TRUE(results.Length() == 1);
+  EXPECT_TRUE(NS_LITERAL_CSTRING("MOZ_LOG=module1:5,module2:4,sync,timestamp").Equals(results[0]));
+
+  char const* argv2[] = { "", "-MOZ_LOG=modules" };
+  results.Clear();
+  mozilla::LoggingHandleCommandLineArgs(array_size(argv2), argv2, callback);
+  EXPECT_TRUE(results.Length() == 1);
+  EXPECT_TRUE(NS_LITERAL_CSTRING("MOZ_LOG=modules").Equals(results[0]));
+
+  char const* argv3[] = { "", "--MOZ_LOG", "modules" };
+  results.Clear();
+  mozilla::LoggingHandleCommandLineArgs(array_size(argv3), argv3, callback);
+  EXPECT_TRUE(results.Length() == 1);
+  EXPECT_TRUE(NS_LITERAL_CSTRING("MOZ_LOG=modules").Equals(results[0]));
+
+  char const* argv4[] = { "", "--MOZ_LOG=modules" };
+  results.Clear();
+  mozilla::LoggingHandleCommandLineArgs(array_size(argv4), argv4, callback);
+  EXPECT_TRUE(results.Length() == 1);
+  EXPECT_TRUE(NS_LITERAL_CSTRING("MOZ_LOG=modules").Equals(results[0]));
+}
+
+TEST(LogCommandLineHandler, MOZ_LOG_and_FILE_regular)
+{
+  nsTArray<nsCString> results;
+
+  auto callback = [&](nsACString const& env) mutable {
+    results.AppendElement(env);
+  };
+
+  char const* argv1[] = { "", "-MOZ_LOG", "modules", "-MOZ_LOG_FILE", "c:\\file/path" };
+  results.Clear();
+  mozilla::LoggingHandleCommandLineArgs(array_size(argv1), argv1, callback);
+  EXPECT_TRUE(results.Length() == 2);
+  EXPECT_TRUE(NS_LITERAL_CSTRING("MOZ_LOG=modules").Equals(results[0]));
+  EXPECT_TRUE(NS_LITERAL_CSTRING("MOZ_LOG_FILE=c:\\file/path").Equals(results[1]));
+
+  char const* argv2[] = { "", "-MOZ_LOG=modules", "-MOZ_LOG_FILE=file" };
+  results.Clear();
+  mozilla::LoggingHandleCommandLineArgs(array_size(argv2), argv2, callback);
+  EXPECT_TRUE(results.Length() == 2);
+  EXPECT_TRUE(NS_LITERAL_CSTRING("MOZ_LOG=modules").Equals(results[0]));
+  EXPECT_TRUE(NS_LITERAL_CSTRING("MOZ_LOG_FILE=file").Equals(results[1]));
+
+  char const* argv3[] = { "", "--MOZ_LOG", "modules", "--MOZ_LOG_FILE", "file" };
+  results.Clear();
+  mozilla::LoggingHandleCommandLineArgs(array_size(argv3), argv3, callback);
+  EXPECT_TRUE(results.Length() == 2);
+  EXPECT_TRUE(NS_LITERAL_CSTRING("MOZ_LOG=modules").Equals(results[0]));
+  EXPECT_TRUE(NS_LITERAL_CSTRING("MOZ_LOG_FILE=file").Equals(results[1]));
+
+  char const* argv4[] = { "", "--MOZ_LOG=modules", "--MOZ_LOG_FILE=file" };
+  results.Clear();
+  mozilla::LoggingHandleCommandLineArgs(array_size(argv4), argv4, callback);
+  EXPECT_TRUE(results.Length() == 2);
+  EXPECT_TRUE(NS_LITERAL_CSTRING("MOZ_LOG=modules").Equals(results[0]));
+  EXPECT_TRUE(NS_LITERAL_CSTRING("MOZ_LOG_FILE=file").Equals(results[1]));
+
+  char const* argv5[] = { "", "--MOZ_LOG", "modules", "-P", "foo", "--MOZ_LOG_FILE", "file" };
+  results.Clear();
+  mozilla::LoggingHandleCommandLineArgs(array_size(argv5), argv5, callback);
+  EXPECT_TRUE(results.Length() == 2);
+  EXPECT_TRUE(NS_LITERAL_CSTRING("MOZ_LOG=modules").Equals(results[0]));
+  EXPECT_TRUE(NS_LITERAL_CSTRING("MOZ_LOG_FILE=file").Equals(results[1]));
+}
+
+TEST(LogCommandLineHandler, MOZ_LOG_fuzzy)
+{
+  nsTArray<nsCString> results;
+
+  auto callback = [&](nsACString const& env) mutable {
+    results.AppendElement(env);
+  };
+
+  char const* argv1[] = { "", "-MOZ_LOG" };
+  results.Clear();
+  mozilla::LoggingHandleCommandLineArgs(array_size(argv1), argv1, callback);
+  EXPECT_TRUE(results.Length() == 0);
+
+  char const* argv2[] = { "", "modules" };
+  results.Clear();
+  mozilla::LoggingHandleCommandLineArgs(array_size(argv2), argv2, callback);
+  EXPECT_TRUE(results.Length() == 0);
+
+  char const* argv3[] = { "", "-MOZ_LOG,modules", "-MOZ_LOG" };
+  results.Clear();
+  mozilla::LoggingHandleCommandLineArgs(array_size(argv3), argv3, callback);
+  EXPECT_TRUE(results.Length() == 0);
+
+  char const* argv4[] = { "", "-MOZ_LOG", "-MOZ_LOG", "-MOZ_LOG" };
+  results.Clear();
+  mozilla::LoggingHandleCommandLineArgs(array_size(argv4), argv4, callback);
+  EXPECT_TRUE(results.Length() == 0);
+
+  char const* argv5[] = { "", "-MOZ_LOG", "-diffent_command", "modules" };
+  results.Clear();
+  mozilla::LoggingHandleCommandLineArgs(array_size(argv5), argv5, callback);
+  EXPECT_TRUE(results.Length() == 0);
+}
+
+TEST(LogCommandLineHandler, MOZ_LOG_overlapping)
+{
+  nsTArray<nsCString> results;
+
+  auto callback = [&](nsACString const& env) mutable {
+    results.AppendElement(env);
+  };
+
+  char const* argv1[] = { "", "-MOZ_LOG=modules1", "-MOZ_LOG=modules2" };
+  results.Clear();
+  mozilla::LoggingHandleCommandLineArgs(array_size(argv1), argv1, callback);
+  EXPECT_TRUE(results.Length() == 2);
+  EXPECT_TRUE(NS_LITERAL_CSTRING("MOZ_LOG=modules1").Equals(results[0]));
+  EXPECT_TRUE(NS_LITERAL_CSTRING("MOZ_LOG=modules2").Equals(results[1]));
+
+  char const* argv2[] = { "", "-MOZ_LOG", "--MOZ_LOG", "modules" };
+  results.Clear();
+  mozilla::LoggingHandleCommandLineArgs(array_size(argv2), argv2, callback);
+  EXPECT_TRUE(results.Length() == 1);
+  EXPECT_TRUE(NS_LITERAL_CSTRING("MOZ_LOG=modules").Equals(results[0]));
+
+  char const* argv3[] = { "", "-MOZ_LOG_FILE", "-MOZ_LOG", "modules" };
+  results.Clear();
+  mozilla::LoggingHandleCommandLineArgs(array_size(argv3), argv3, callback);
+  EXPECT_TRUE(results.Length() == 1);
+  EXPECT_TRUE(NS_LITERAL_CSTRING("MOZ_LOG=modules").Equals(results[0]));
+
+  char const* argv4[] = { "", "-MOZ_LOG", "-MOZ_LOG_FILE", "-MOZ_LOG" };
+  results.Clear();
+  mozilla::LoggingHandleCommandLineArgs(array_size(argv4), argv4, callback);
+  EXPECT_TRUE(results.Length() == 0);
+}
diff --git a/xpcom/tests/gtest/moz.build b/xpcom/tests/gtest/moz.build
index 22c491870969..28f20360e543 100644
--- a/xpcom/tests/gtest/moz.build
+++ b/xpcom/tests/gtest/moz.build
@@ -25,6 +25,7 @@ UNIFIED_SOURCES += [
     'TestFile.cpp',
     'TestGCPostBarriers.cpp',
     'TestID.cpp',
+    'TestLogCommandLineHandler.cpp',
     'TestMoveString.cpp',
     'TestMozPromise.cpp',
     'TestMultiplexInputStream.cpp',