From 9f3b16bf4c0a471a4f195a92e789c8761d3f0922 Mon Sep 17 00:00:00 2001 From: Tom Tromey Date: Fri, 24 Jul 2015 07:01:00 -0400 Subject: [PATCH] Bug 1148593 - Create async stack in callback objects. r=bz, r=fitzgen --HG-- extra : rebase_source : f9b507d8f005dbca6f40f510ca41a0cbb03aebf9 --- .../browser_canvas-frontend-call-stack-01.js | 6 +- .../browser_canvas-frontend-call-stack-02.js | 6 +- .../browser_canvas-frontend-call-stack-03.js | 12 +- .../browser_timelineMarkers-frame-05.js | 2 +- dom/base/test/mochitest.ini | 2 + .../test/test_async_setTimeout_stack.html | 60 ++++++++++ ...async_setTimeout_stack_across_globals.html | 60 ++++++++++ dom/bindings/CallbackObject.cpp | 11 ++ dom/bindings/CallbackObject.h | 34 +++++- dom/bindings/test/mochitest.ini | 1 + dom/bindings/test/test_async_stacks.html | 108 ++++++++++++++++++ ..._exception_options_from_jsimplemented.html | 56 +++++---- ...promise_rejections_from_jsimplemented.html | 44 ++++--- js/src/builtin/TestingFunctions.cpp | 3 +- js/src/jsapi.cpp | 8 +- js/src/jsapi.h | 13 ++- js/src/vm/Runtime.cpp | 1 + js/src/vm/Runtime.h | 6 + js/src/vm/SavedStacks.cpp | 15 ++- js/src/vm/Stack-inl.h | 3 + js/src/vm/Stack.h | 8 ++ js/xpconnect/src/XPCComponents.cpp | 3 +- toolkit/modules/Promise-backend.js | 14 ++- 23 files changed, 421 insertions(+), 55 deletions(-) create mode 100644 dom/base/test/test_async_setTimeout_stack.html create mode 100644 dom/base/test/test_async_setTimeout_stack_across_globals.html create mode 100644 dom/bindings/test/test_async_stacks.html diff --git a/browser/devtools/canvasdebugger/test/browser_canvas-frontend-call-stack-01.js b/browser/devtools/canvasdebugger/test/browser_canvas-frontend-call-stack-01.js index 92ca163e5733..21b7d4e8ed6f 100644 --- a/browser/devtools/canvasdebugger/test/browser_canvas-frontend-call-stack-01.js +++ b/browser/devtools/canvasdebugger/test/browser_canvas-frontend-call-stack-01.js @@ -28,8 +28,10 @@ function* ifTestingSupported() { isnot($(".call-item-stack", callItem.target), null, "There should be a stack container available now for the draw call."); - is($all(".call-item-stack-fn", callItem.target).length, 4, - "There should be 4 functions on the stack for the draw call."); + // We may have more than 4 functions, depending on whether async + // stacks are available. + ok($all(".call-item-stack-fn", callItem.target).length >= 4, + "There should be at least 4 functions on the stack for the draw call."); ok($all(".call-item-stack-fn-name", callItem.target)[0].getAttribute("value") .includes("C()"), diff --git a/browser/devtools/canvasdebugger/test/browser_canvas-frontend-call-stack-02.js b/browser/devtools/canvasdebugger/test/browser_canvas-frontend-call-stack-02.js index bc3be3e169b3..491aa695eb00 100644 --- a/browser/devtools/canvasdebugger/test/browser_canvas-frontend-call-stack-02.js +++ b/browser/devtools/canvasdebugger/test/browser_canvas-frontend-call-stack-02.js @@ -29,8 +29,10 @@ function* ifTestingSupported() { isnot($(".call-item-stack", callItem.target), null, "There should be a stack container available now for the draw call."); - is($all(".call-item-stack-fn", callItem.target).length, 4, - "There should be 4 functions on the stack for the draw call."); + // We may have more than 4 functions, depending on whether async + // stacks are available. + ok($all(".call-item-stack-fn", callItem.target).length >= 4, + "There should be at least 4 functions on the stack for the draw call."); let jumpedToSource = once(window, EVENTS.SOURCE_SHOWN_IN_JS_DEBUGGER); EventUtils.sendMouseEvent({ type: "mousedown" }, $(".call-item-location", callItem.target)); diff --git a/browser/devtools/canvasdebugger/test/browser_canvas-frontend-call-stack-03.js b/browser/devtools/canvasdebugger/test/browser_canvas-frontend-call-stack-03.js index 796e329123ce..24780c566102 100644 --- a/browser/devtools/canvasdebugger/test/browser_canvas-frontend-call-stack-03.js +++ b/browser/devtools/canvasdebugger/test/browser_canvas-frontend-call-stack-03.js @@ -40,8 +40,10 @@ function* ifTestingSupported() { "There should be a stack container available now for the draw call."); is($(".call-item-stack", callItem.target).hidden, false, "The stack container should now be visible."); - is($all(".call-item-stack-fn", callItem.target).length, 4, - "There should be 4 functions on the stack for the draw call."); + // We may have more than 4 functions, depending on whether async + // stacks are available. + ok($all(".call-item-stack-fn", callItem.target).length >= 4, + "There should be at least 4 functions on the stack for the draw call."); EventUtils.sendMouseEvent({ type: "dblclick" }, contents, window); @@ -53,8 +55,10 @@ function* ifTestingSupported() { "There should still be a stack container available for the draw call."); is($(".call-item-stack", callItem.target).hidden, true, "The stack container should now be hidden."); - is($all(".call-item-stack-fn", callItem.target).length, 4, - "There should still be 4 functions on the stack for the draw call."); + // We may have more than 4 functions, depending on whether async + // stacks are available. + ok($all(".call-item-stack-fn", callItem.target).length >= 4, + "There should still be at least 4 functions on the stack for the draw call."); yield teardown(panel); finish(); diff --git a/docshell/test/browser/browser_timelineMarkers-frame-05.js b/docshell/test/browser/browser_timelineMarkers-frame-05.js index bca5d882a9f2..2f8bd05f6611 100644 --- a/docshell/test/browser/browser_timelineMarkers-frame-05.js +++ b/docshell/test/browser/browser_timelineMarkers-frame-05.js @@ -94,7 +94,7 @@ if (Services.prefs.getBoolPref("javascript.options.asyncstack")) { let frame = markers[0].endStack; ok(frame.parent.asyncParent !== null, "Parent frame has async parent"); - is(frame.parent.asyncParent.asyncCause, "Promise", + is(frame.parent.asyncParent.asyncCause, "promise callback", "Async parent has correct cause"); is(frame.parent.asyncParent.functionDisplayName, "makePromise", "Async parent has correct function name"); diff --git a/dom/base/test/mochitest.ini b/dom/base/test/mochitest.ini index e7862fb30332..9473eb0f82ec 100644 --- a/dom/base/test/mochitest.ini +++ b/dom/base/test/mochitest.ini @@ -248,6 +248,8 @@ support-files = [test_anonymousContent_insert.html] [test_anonymousContent_manipulate_content.html] [test_appname_override.html] +[test_async_setTimeout_stack.html] +[test_async_setTimeout_stack_across_globals.html] [test_audioWindowUtils.html] [test_audioNotification.html] skip-if = buildapp == 'mulet' diff --git a/dom/base/test/test_async_setTimeout_stack.html b/dom/base/test/test_async_setTimeout_stack.html new file mode 100644 index 000000000000..fb3c74b29116 --- /dev/null +++ b/dom/base/test/test_async_setTimeout_stack.html @@ -0,0 +1,60 @@ + + + + + + Test for Bug 1142577 - Async stacks for setTimeout + + + + + Mozilla Bug 1142577 + 

+  
+
+
diff --git a/dom/base/test/test_async_setTimeout_stack_across_globals.html b/dom/base/test/test_async_setTimeout_stack_across_globals.html
new file mode 100644
index 000000000000..5b44072d6f31
--- /dev/null
+++ b/dom/base/test/test_async_setTimeout_stack_across_globals.html
@@ -0,0 +1,60 @@
+
+
+
+
+  
+  Test for Bug 1142577 - Async stacks for setTimeout
+  
+  
+
+
+  Mozilla Bug 1142577
+  

+  
+  
+
+
diff --git a/dom/bindings/CallbackObject.cpp b/dom/bindings/CallbackObject.cpp
index b1e2b62cf19b..e119d99a71bc 100644
--- a/dom/bindings/CallbackObject.cpp
+++ b/dom/bindings/CallbackObject.cpp
@@ -43,6 +43,7 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(CallbackObject)
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(CallbackObject)
   NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mCallback)
+  NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mCreationStack)
   NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mIncumbentJSGlobal)
 NS_IMPL_CYCLE_COLLECTION_TRACE_END
 
@@ -169,6 +170,16 @@ CallbackObject::CallSetup::CallSetup(CallbackObject* aCallback,
     }
   }
 
+  mAsyncStack.emplace(cx, aCallback->GetCreationStack());
+  if (*mAsyncStack) {
+    mAsyncCause.emplace(cx, JS_NewStringCopyZ(cx, aExecutionReason));
+    if (*mAsyncCause) {
+      mAsyncStackSetter.emplace(cx, *mAsyncStack, *mAsyncCause);
+    } else {
+      JS_ClearPendingException(cx);
+    }
+  }
+
   // Enter the compartment of our callback, so we can actually work with it.
   //
   // Note that if the callback is a wrapper, this will not be the same
diff --git a/dom/bindings/CallbackObject.h b/dom/bindings/CallbackObject.h
index 5ba68fdf13c6..ff1bdcbf039f 100644
--- a/dom/bindings/CallbackObject.h
+++ b/dom/bindings/CallbackObject.h
@@ -30,6 +30,7 @@
 #include "nsWrapperCache.h"
 #include "nsJSEnvironment.h"
 #include "xpcpublic.h"
+#include "jsapi.h"
 
 namespace mozilla {
 namespace dom {
@@ -56,7 +57,15 @@ public:
   explicit CallbackObject(JSContext* aCx, JS::Handle aCallback,
                           nsIGlobalObject *aIncumbentGlobal)
   {
-    Init(aCallback, aIncumbentGlobal);
+    if (aCx && JS::RuntimeOptionsRef(aCx).asyncStack()) {
+      JS::RootedObject stack(aCx);
+      if (!JS::CaptureCurrentStack(aCx, &stack)) {
+        JS_ClearPendingException(aCx);
+      }
+      Init(aCallback, stack, aIncumbentGlobal);
+    } else {
+      Init(aCallback, nullptr, aIncumbentGlobal);
+    }
   }
 
   JS::Handle Callback() const
@@ -65,6 +74,15 @@ public:
     return CallbackPreserveColor();
   }
 
+  JSObject* GetCreationStack() const
+  {
+    JSObject* result = mCreationStack;
+    if (result) {
+      JS::ExposeObjectToActiveJS(result);
+    }
+    return result;
+  }
+
   /*
    * This getter does not change the color of the JSObject meaning that the
    * object returned is not guaranteed to be kept alive past the next CC.
@@ -112,7 +130,8 @@ protected:
 
   explicit CallbackObject(CallbackObject* aCallbackObject)
   {
-    Init(aCallbackObject->mCallback, aCallbackObject->mIncumbentGlobal);
+    Init(aCallbackObject->mCallback, aCallbackObject->mCreationStack,
+         aCallbackObject->mIncumbentGlobal);
   }
 
   bool operator==(const CallbackObject& aOther) const
@@ -125,12 +144,14 @@ protected:
   }
 
 private:
-  inline void Init(JSObject* aCallback, nsIGlobalObject* aIncumbentGlobal)
+  inline void Init(JSObject* aCallback, JSObject* aCreationStack,
+                   nsIGlobalObject* aIncumbentGlobal)
   {
     MOZ_ASSERT(aCallback && !mCallback);
     // Set script objects before we hold, on the off chance that a GC could
     // somehow happen in there... (which would be pretty odd, granted).
     mCallback = aCallback;
+    mCreationStack = aCreationStack;
     if (aIncumbentGlobal) {
       mIncumbentGlobal = aIncumbentGlobal;
       mIncumbentJSGlobal = aIncumbentGlobal->GetGlobalJSObject();
@@ -147,12 +168,14 @@ protected:
     MOZ_ASSERT_IF(mIncumbentJSGlobal, mCallback);
     if (mCallback) {
       mCallback = nullptr;
+      mCreationStack = nullptr;
       mIncumbentJSGlobal = nullptr;
       mozilla::DropJSObjects(this);
     }
   }
 
   JS::Heap mCallback;
+  JS::Heap mCreationStack;
   // Ideally, we'd just hold a reference to the nsIGlobalObject, since that's
   // what we need to pass to AutoIncumbentScript. Unfortunately, that doesn't
   // hold the actual JS global alive. So we maintain an additional pointer to
@@ -213,6 +236,11 @@ protected:
     // always within a request during its lifetime.
     Maybe > mRootedCallable;
 
+    // Members which are used to set the async stack.
+    Maybe> mAsyncStack;
+    Maybe> mAsyncCause;
+    Maybe mAsyncStackSetter;
+
     // Can't construct a JSAutoCompartment without a JSContext either.  Also,
     // Put mAc after mAutoEntryScript so that we exit the compartment before
     // we pop the JSContext. Though in practice we'll often manually order
diff --git a/dom/bindings/test/mochitest.ini b/dom/bindings/test/mochitest.ini
index 557a3c914e55..3b82263d0fb7 100644
--- a/dom/bindings/test/mochitest.ini
+++ b/dom/bindings/test/mochitest.ini
@@ -8,6 +8,7 @@ support-files =
   file_proxies_via_xray.html
   forOf_iframe.html
 
+[test_async_stacks.html]
 [test_ByteString.html]
 [test_InstanceOf.html]
 [test_bug560072.html]
diff --git a/dom/bindings/test/test_async_stacks.html b/dom/bindings/test/test_async_stacks.html
new file mode 100644
index 000000000000..8b655a14d70c
--- /dev/null
+++ b/dom/bindings/test/test_async_stacks.html
@@ -0,0 +1,108 @@
+
+
+
+
+  
+  Test for Bug 1148593
+  
+  
+  
+
+
+Mozilla Bug 1148593
+

+
+
+

+
+
diff --git a/dom/bindings/test/test_exception_options_from_jsimplemented.html b/dom/bindings/test/test_exception_options_from_jsimplemented.html
index 61ff8bc98b8a..32bf6ca31c85 100644
--- a/dom/bindings/test/test_exception_options_from_jsimplemented.html
+++ b/dom/bindings/test/test_exception_options_from_jsimplemented.html
@@ -15,6 +15,17 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=1107592
   SimpleTest.waitForExplicitFinish();
 
   function doTest() {
+    var file = location.href;
+    var asyncFrame;
+    /* Async parent frames from pushPrefEnv don't show up in e10s.  */
+    var isE10S = !SpecialPowers.Services.wm.getMostRecentWindow("navigator:browser");
+    if (!isE10S && SpecialPowers.getBoolPref("javascript.options.asyncstack")) {
+      asyncFrame = `Async*@${file}:153:1
+`;
+    } else {
+      asyncFrame = "";
+    }
+
     var t = new TestInterfaceJS();
     try {
       t.testThrowError();
@@ -25,12 +36,13 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=1107592
       is(e.name, "Error", "Should not have an interesting name here");
       is(e.message, "We are an Error", "Should have the right message");
       is(e.stack,
-         "doTest@http://mochi.test:8888/tests/dom/bindings/test/test_exception_options_from_jsimplemented.html:20:7\n",
+         `doTest@${file}:31:7
+${asyncFrame}`,
          "Exception stack should still only show our code");
       is(e.fileName,
-         "http://mochi.test:8888/tests/dom/bindings/test/test_exception_options_from_jsimplemented.html",
+         file,
          "Should have the right file name");
-      is(e.lineNumber, 20, "Should have the right line number");
+      is(e.lineNumber, 31, "Should have the right line number");
       is(e.columnNumber, 7, "Should have the right column number");
     }
 
@@ -45,12 +57,13 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=1107592
       is(e.code, DOMException.NOT_SUPPORTED_ERR,
          "Should have the right 'code'");
       is(e.stack,
-         "doTest@http://mochi.test:8888/tests/dom/bindings/test/test_exception_options_from_jsimplemented.html:38:7\n",
+         `doTest@${file}:50:7
+${asyncFrame}`,
          "Exception stack should still only show our code");
       is(e.filename,
-         "http://mochi.test:8888/tests/dom/bindings/test/test_exception_options_from_jsimplemented.html",
+         file,
          "Should still have the right file name");
-      is(e.lineNumber, 38, "Should still have the right line number");
+      is(e.lineNumber, 50, "Should still have the right line number");
       todo_isnot(e.columnNumber, 0,
                  "No column number support for DOMException yet");
     }
@@ -65,12 +78,13 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=1107592
       is(e.message, "We are a TypeError",
          "Should also have the right message (2)");
       is(e.stack,
-         "doTest@http://mochi.test:8888/tests/dom/bindings/test/test_exception_options_from_jsimplemented.html:59:7\n",
+         `doTest@${file}:72:7
+${asyncFrame}`,
          "Exception stack for TypeError should only show our code");
       is(e.fileName,
-         "http://mochi.test:8888/tests/dom/bindings/test/test_exception_options_from_jsimplemented.html",
+         file,
          "Should still have the right file name for TypeError");
-      is(e.lineNumber, 59, "Should still have the right line number for TypeError");
+      is(e.lineNumber, 72, "Should still have the right line number for TypeError");
       is(e.columnNumber, 7, "Should have the right column number for TypeError");
     }
 
@@ -84,14 +98,14 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=1107592
       is(e.message, "missing argument 0 when calling function Array.indexOf",
          "Should also have the right message (3)");
       is(e.stack,
-         "doTest/<@http://mochi.test:8888/tests/dom/bindings/test/test_exception_options_from_jsimplemented.html:78:45\n" +
-         "doTest@http://mochi.test:8888/tests/dom/bindings/test/test_exception_options_from_jsimplemented.html:78:7\n"
-  ,
+         `doTest/<@${file}:92:45
+doTest@${file}:92:7
+${asyncFrame}`,
          "Exception stack for TypeError should only show our code (3)");
       is(e.fileName,
-         "http://mochi.test:8888/tests/dom/bindings/test/test_exception_options_from_jsimplemented.html",
+         file,
          "Should still have the right file name for TypeError (3)");
-      is(e.lineNumber, 78, "Should still have the right line number for TypeError (3)");
+      is(e.lineNumber, 92, "Should still have the right line number for TypeError (3)");
       is(e.columnNumber, 45, "Should have the right column number for TypeError (3)");
     }
 
@@ -104,12 +118,13 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=1107592
       is(e.name, "NS_ERROR_UNEXPECTED", "Name should be sanitized (4)");
       is(e.message, "", "Message should be sanitized (5)");
       is(e.stack,
-         "doTest@http://mochi.test:8888/tests/dom/bindings/test/test_exception_options_from_jsimplemented.html:99:7\n",
+         `doTest@${file}:113:7
+${asyncFrame}`,
          "Exception stack for sanitized exception should only show our code (4)");
       is(e.filename,
-         "http://mochi.test:8888/tests/dom/bindings/test/test_exception_options_from_jsimplemented.html",
+         file,
          "Should still have the right file name for sanitized exception (4)");
-      is(e.lineNumber, 99, "Should still have the right line number for sanitized exception (4)");
+      is(e.lineNumber, 113, "Should still have the right line number for sanitized exception (4)");
       todo_isnot(e.columnNumber, 0, "Should have the right column number for sanitized exception (4)");
     }
 
@@ -122,12 +137,13 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=1107592
       is(e.name, "NS_ERROR_UNEXPECTED", "Name should be sanitized (5)");
       is(e.message, "", "Message should be sanitized (5)");
       is(e.stack,
-         "doTest@http://mochi.test:8888/tests/dom/bindings/test/test_exception_options_from_jsimplemented.html:117:7\n",
+         `doTest@${file}:132:7
+${asyncFrame}`,
          "Exception stack for sanitized exception should only show our code (5)");
       is(e.filename,
-         "http://mochi.test:8888/tests/dom/bindings/test/test_exception_options_from_jsimplemented.html",
+         file,
          "Should still have the right file name for sanitized exception (5)");
-      is(e.lineNumber, 117, "Should still have the right line number for sanitized exception (5)");
+      is(e.lineNumber, 132, "Should still have the right line number for sanitized exception (5)");
       todo_isnot(e.columnNumber, 0, "Should have the right column number for sanitized exception (5)");
     }
 
diff --git a/dom/bindings/test/test_promise_rejections_from_jsimplemented.html b/dom/bindings/test/test_promise_rejections_from_jsimplemented.html
index d109d5ec8993..6c9b5f22b2a2 100644
--- a/dom/bindings/test/test_promise_rejections_from_jsimplemented.html
+++ b/dom/bindings/test/test_promise_rejections_from_jsimplemented.html
@@ -37,23 +37,32 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=1107592
 
   function doTest() {
     var t = new TestInterfaceJS();
+    /* Async parent frames from pushPrefEnv don't show up in e10s.  */
+    var isE10S = !SpecialPowers.Services.wm.getMostRecentWindow("navigator:browser");
     var asyncStack = SpecialPowers.getBoolPref("javascript.options.asyncstack");
-    var ourFile = "http://mochi.test:8888/tests/dom/bindings/test/test_promise_rejections_from_jsimplemented.html";
+    var ourFile = location.href;
+    var parentFrame = (asyncStack && !isE10S) ? `Async*@${ourFile}:121:1
+` : "";
 
     Promise.all([
       t.testPromiseWithThrowingChromePromiseInit().then(
           ensurePromiseFail.bind(null, 1),
-          checkExn.bind(null, 44, "NS_ERROR_UNEXPECTED", "", undefined,
+          checkExn.bind(null, 48, "NS_ERROR_UNEXPECTED", "", undefined,
                         ourFile, 1,
-                        "doTest@http://mochi.test:8888/tests/dom/bindings/test/test_promise_rejections_from_jsimplemented.html:44:7\n")),
+                        `doTest@${ourFile}:48:7
+` +
+                        parentFrame)),
       t.testPromiseWithThrowingContentPromiseInit(function() {
           thereIsNoSuchContentFunction1();
         }).then(
           ensurePromiseFail.bind(null, 2),
-          checkExn.bind(null, 50, "ReferenceError",
+          checkExn.bind(null, 56, "ReferenceError",
                         "thereIsNoSuchContentFunction1 is not defined",
                         undefined, ourFile, 2,
-                        "doTest/<@http://mochi.test:8888/tests/dom/bindings/test/test_promise_rejections_from_jsimplemented.html:50:11\ndoTest@http://mochi.test:8888/tests/dom/bindings/test/test_promise_rejections_from_jsimplemented.html:49:7\n")),
+                        `doTest/<@${ourFile}:56:11
+doTest@${ourFile}:55:7
+` +
+                        parentFrame)),
       t.testPromiseWithThrowingChromeThenFunction().then(
           ensurePromiseFail.bind(null, 3),
           checkExn.bind(null, 0, "NS_ERROR_UNEXPECTED", "", undefined, "", 3, "")),
@@ -61,10 +70,14 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=1107592
           thereIsNoSuchContentFunction2();
         }).then(
           ensurePromiseFail.bind(null, 4),
-          checkExn.bind(null, 61, "ReferenceError",
+          checkExn.bind(null, 70, "ReferenceError",
                         "thereIsNoSuchContentFunction2 is not defined",
                         undefined, ourFile, 4,
-                        "doTest/<@http://mochi.test:8888/tests/dom/bindings/test/test_promise_rejections_from_jsimplemented.html:61:11\n" + (asyncStack ? "Async*doTest@http://mochi.test:8888/tests/dom/bindings/test/test_promise_rejections_from_jsimplemented.html:60:7\n" : ""))),
+                        `doTest/<@${ourFile}:70:11
+` +
+                        (asyncStack ? `Async*doTest@${ourFile}:69:7
+` : "") +
+                        parentFrame)),
       t.testPromiseWithThrowingChromeThenable().then(
           ensurePromiseFail.bind(null, 5),
           checkExn.bind(null, 0, "NS_ERROR_UNEXPECTED", "", undefined, "", 5, "")),
@@ -72,22 +85,27 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=1107592
             then: function() { thereIsNoSuchContentFunction3(); }
         }).then(
           ensurePromiseFail.bind(null, 6),
-          checkExn.bind(null, 72, "ReferenceError",
+          checkExn.bind(null, 85, "ReferenceError",
                         "thereIsNoSuchContentFunction3 is not defined",
                         undefined, ourFile, 6,
-                        "doTest/<.then@http://mochi.test:8888/tests/dom/bindings/test/test_promise_rejections_from_jsimplemented.html:72:32\n")),
+                        `doTest/<.then@${ourFile}:85:32
+`)),
       t.testPromiseWithDOMExceptionThrowingPromiseInit().then(
           ensurePromiseFail.bind(null, 7),
-          checkExn.bind(null, 79, "NotFoundError",
+          checkExn.bind(null, 93, "NotFoundError",
                         "We are a second DOMException",
                         DOMException.NOT_FOUND_ERR, ourFile, 7,
-                        "doTest@http://mochi.test:8888/tests/dom/bindings/test/test_promise_rejections_from_jsimplemented.html:79:7\n")),
+                        `doTest@${ourFile}:93:7
+` +
+                        parentFrame)),
       t.testPromiseWithDOMExceptionThrowingThenFunction().then(
           ensurePromiseFail.bind(null, 8),
-          checkExn.bind(null, asyncStack ? 85 : 0, "NetworkError",
+          checkExn.bind(null, asyncStack ? 101 : 0, "NetworkError",
                          "We are a third DOMException",
                         DOMException.NETWORK_ERR, asyncStack ? ourFile : "", 8,
-                        asyncStack ? "Async*doTest@http://mochi.test:8888/tests/dom/bindings/test/test_promise_rejections_from_jsimplemented.html:85:7\n" : "")),
+                        (asyncStack ? `Async*doTest@${ourFile}:101:7
+` +
+                         parentFrame : ""))),
       t.testPromiseWithDOMExceptionThrowingThenable().then(
           ensurePromiseFail.bind(null, 9),
           checkExn.bind(null, 0, "TypeMismatchError",
diff --git a/js/src/builtin/TestingFunctions.cpp b/js/src/builtin/TestingFunctions.cpp
index a0e4bb33f542..868b077ee27f 100644
--- a/js/src/builtin/TestingFunctions.cpp
+++ b/js/src/builtin/TestingFunctions.cpp
@@ -943,7 +943,8 @@ CallFunctionWithAsyncStack(JSContext* cx, unsigned argc, Value* vp)
     RootedObject stack(cx, &args[1].toObject());
     RootedString asyncCause(cx, args[2].toString());
 
-    JS::AutoSetAsyncStackForNewCalls sas(cx, stack, asyncCause);
+    JS::AutoSetAsyncStackForNewCalls sas(cx, stack, asyncCause,
+                                         JS::AutoSetAsyncStackForNewCalls::AsyncCallKind::EXPLICIT);
     return Call(cx, UndefinedHandleValue, function,
                 JS::HandleValueArray::empty(), args.rval());
 }
diff --git a/js/src/jsapi.cpp b/js/src/jsapi.cpp
index 946ba63cc99e..3c6327b22c7c 100644
--- a/js/src/jsapi.cpp
+++ b/js/src/jsapi.cpp
@@ -4730,10 +4730,12 @@ JS_RestoreFrameChain(JSContext* cx)
 }
 
 JS::AutoSetAsyncStackForNewCalls::AutoSetAsyncStackForNewCalls(
-  JSContext* cx, HandleObject stack, HandleString asyncCause)
+  JSContext* cx, HandleObject stack, HandleString asyncCause,
+  JS::AutoSetAsyncStackForNewCalls::AsyncCallKind kind)
   : cx(cx),
     oldAsyncStack(cx, cx->runtime()->asyncStackForNewActivations),
-    oldAsyncCause(cx, cx->runtime()->asyncCauseForNewActivations)
+    oldAsyncCause(cx, cx->runtime()->asyncCauseForNewActivations),
+    oldAsyncCallIsExplicit(cx->runtime()->asyncCallIsExplicit)
 {
     CHECK_REQUEST(cx);
 
@@ -4748,6 +4750,7 @@ JS::AutoSetAsyncStackForNewCalls::AutoSetAsyncStackForNewCalls(
 
     cx->runtime()->asyncStackForNewActivations = asyncStack;
     cx->runtime()->asyncCauseForNewActivations = asyncCause;
+    cx->runtime()->asyncCallIsExplicit = kind == AsyncCallKind::EXPLICIT;
 }
 
 JS::AutoSetAsyncStackForNewCalls::~AutoSetAsyncStackForNewCalls()
@@ -4755,6 +4758,7 @@ JS::AutoSetAsyncStackForNewCalls::~AutoSetAsyncStackForNewCalls()
     cx->runtime()->asyncCauseForNewActivations = oldAsyncCause;
     cx->runtime()->asyncStackForNewActivations =
       oldAsyncStack ? &oldAsyncStack->as() : nullptr;
+    cx->runtime()->asyncCallIsExplicit = oldAsyncCallIsExplicit;
 }
 
 /************************************************************************/
diff --git a/js/src/jsapi.h b/js/src/jsapi.h
index 7b13c55438a9..ee9b01bf838e 100644
--- a/js/src/jsapi.h
+++ b/js/src/jsapi.h
@@ -4027,14 +4027,25 @@ class MOZ_STACK_CLASS JS_PUBLIC_API(AutoSetAsyncStackForNewCalls)
     JSContext* cx;
     RootedObject oldAsyncStack;
     RootedString oldAsyncCause;
+    bool oldAsyncCallIsExplicit;
 
   public:
+    enum class AsyncCallKind {
+        // The ordinary kind of call, where we may apply an async
+        // parent if there is no ordinary parent.
+        IMPLICIT,
+        // An explicit async parent, e.g., callFunctionWithAsyncStack,
+        // where we always want to override any ordinary parent.
+        EXPLICIT
+    };
+
     // The stack parameter cannot be null by design, because it would be
     // ambiguous whether that would clear any scheduled async stack and make the
     // normal stack reappear in the new call, or just keep the async stack
     // already scheduled for the new call, if any.
     AutoSetAsyncStackForNewCalls(JSContext* cx, HandleObject stack,
-                                 HandleString asyncCause);
+                                 HandleString asyncCause,
+                                 AsyncCallKind kind = AsyncCallKind::IMPLICIT);
     ~AutoSetAsyncStackForNewCalls();
 };
 
diff --git a/js/src/vm/Runtime.cpp b/js/src/vm/Runtime.cpp
index 15e7c7b93019..f8309f05483b 100644
--- a/js/src/vm/Runtime.cpp
+++ b/js/src/vm/Runtime.cpp
@@ -128,6 +128,7 @@ JSRuntime::JSRuntime(JSRuntime* parentRuntime)
     asmJSActivationStack_(nullptr),
     asyncStackForNewActivations(nullptr),
     asyncCauseForNewActivations(nullptr),
+    asyncCallIsExplicit(false),
     entryMonitor(nullptr),
     parentRuntime(parentRuntime),
     interrupt_(false),
diff --git a/js/src/vm/Runtime.h b/js/src/vm/Runtime.h
index 0e72361fd48e..d4a6dde87f66 100644
--- a/js/src/vm/Runtime.h
+++ b/js/src/vm/Runtime.h
@@ -697,6 +697,12 @@ struct JSRuntime : public JS::shadow::Runtime,
      */
     JSString* asyncCauseForNewActivations;
 
+    /*
+     * True if the async call was explicitly requested, e.g. via
+     * callFunctionWithAsyncStack.
+     */
+    bool asyncCallIsExplicit;
+
     /* If non-null, report JavaScript entry points to this monitor. */
     JS::dbg::AutoEntryMonitor* entryMonitor;
 
diff --git a/js/src/vm/SavedStacks.cpp b/js/src/vm/SavedStacks.cpp
index ca1d714768b4..481f92fae75b 100644
--- a/js/src/vm/SavedStacks.cpp
+++ b/js/src/vm/SavedStacks.cpp
@@ -912,6 +912,17 @@ SavedStacks::insertFrames(JSContext* cx, FrameIter& iter, MutableHandleSavedFram
     while (!iter.done()) {
         Activation& activation = *iter.activation();
 
+        if (asyncActivation && asyncActivation != &activation) {
+            // We found an async stack in the previous activation, and we
+            // walked past the oldest frame of that activation, we're done.
+            // However, we only want to use the async parent if it was
+            // explicitly requested; if we got here otherwise, we have
+            // a direct parent, which we prefer.
+            if (asyncActivation->asyncCallIsExplicit())
+                break;
+            asyncActivation = nullptr;
+        }
+
         if (!asyncActivation) {
             asyncStack = activation.asyncStack();
             if (asyncStack) {
@@ -923,10 +934,6 @@ SavedStacks::insertFrames(JSContext* cx, FrameIter& iter, MutableHandleSavedFram
                 asyncCause = activation.asyncCause();
                 asyncActivation = &activation;
             }
-        } else if (asyncActivation != &activation) {
-            // We found an async stack in the previous activation, and we
-            // walked past the oldest frame of that activation, we're done.
-            break;
         }
 
         AutoLocationValueRooter location(cx);
diff --git a/js/src/vm/Stack-inl.h b/js/src/vm/Stack-inl.h
index 254eff6687a9..93691f519979 100644
--- a/js/src/vm/Stack-inl.h
+++ b/js/src/vm/Stack-inl.h
@@ -868,11 +868,13 @@ Activation::Activation(JSContext* cx, Kind kind)
     hideScriptedCallerCount_(0),
     asyncStack_(cx, cx->runtime_->asyncStackForNewActivations),
     asyncCause_(cx, cx->runtime_->asyncCauseForNewActivations),
+    asyncCallIsExplicit_(cx->runtime_->asyncCallIsExplicit),
     entryMonitor_(cx->runtime_->entryMonitor),
     kind_(kind)
 {
     cx->runtime_->asyncStackForNewActivations = nullptr;
     cx->runtime_->asyncCauseForNewActivations = nullptr;
+    cx->runtime_->asyncCallIsExplicit = false;
     cx->runtime_->entryMonitor = nullptr;
     cx->runtime_->activation_ = this;
 }
@@ -886,6 +888,7 @@ Activation::~Activation()
     cx_->runtime_->entryMonitor = entryMonitor_;
     cx_->runtime_->asyncCauseForNewActivations = asyncCause_;
     cx_->runtime_->asyncStackForNewActivations = asyncStack_;
+    cx_->runtime_->asyncCallIsExplicit = asyncCallIsExplicit_;
 }
 
 bool
diff --git a/js/src/vm/Stack.h b/js/src/vm/Stack.h
index ffda53d372e6..8f26aedcf37c 100644
--- a/js/src/vm/Stack.h
+++ b/js/src/vm/Stack.h
@@ -1130,6 +1130,10 @@ class Activation
     // Value of asyncCause to be attached to asyncStack_.
     RootedString asyncCause_;
 
+    // True if the async call was explicitly requested, e.g. via
+    // callFunctionWithAsyncStack.
+    bool asyncCallIsExplicit_;
+
     // The entry point monitor that was set on cx_->runtime() when this
     // Activation was created. Subclasses should report their entry frame's
     // function or script here.
@@ -1215,6 +1219,10 @@ class Activation
         return asyncCause_;
     }
 
+    bool asyncCallIsExplicit() const {
+        return asyncCallIsExplicit_;
+    }
+
   private:
     Activation(const Activation& other) = delete;
     void operator=(const Activation& other) = delete;
diff --git a/js/xpconnect/src/XPCComponents.cpp b/js/xpconnect/src/XPCComponents.cpp
index 3513381ad3f8..c91a73101fb2 100644
--- a/js/xpconnect/src/XPCComponents.cpp
+++ b/js/xpconnect/src/XPCComponents.cpp
@@ -2824,7 +2824,8 @@ nsXPCComponents_Utils::CallFunctionWithAsyncStack(HandleValue function,
     if (!asyncCauseString)
         return NS_ERROR_OUT_OF_MEMORY;
 
-    JS::AutoSetAsyncStackForNewCalls sas(cx, asyncStackObj, asyncCauseString);
+    JS::AutoSetAsyncStackForNewCalls sas(cx, asyncStackObj, asyncCauseString,
+                                         JS::AutoSetAsyncStackForNewCalls::AsyncCallKind::EXPLICIT);
 
     if (!JS_CallFunctionValue(cx, nullptr, function,
                               JS::HandleValueArray::empty(), retval))
diff --git a/toolkit/modules/Promise-backend.js b/toolkit/modules/Promise-backend.js
index bf2105384f84..fb5c958ce2da 100644
--- a/toolkit/modules/Promise-backend.js
+++ b/toolkit/modules/Promise-backend.js
@@ -43,6 +43,10 @@
 let Cu = this.require ? require("chrome").Cu : Components.utils;
 let Cc = this.require ? require("chrome").Cc : Components.classes;
 let Ci = this.require ? require("chrome").Ci : Components.interfaces;
+// If we can access Components, then we use it to capture an async
+// parent stack trace; see scheduleWalkerLoop.  However, as it might
+// not be available (see above), users of this must check it first.
+let Components_ = this.require ? require("chrome").components : Components;
 
 // If Cu is defined, use it to lazily define the FinalizationWitnessService.
 if (Cu) {
@@ -737,7 +741,15 @@ this.PromiseWalker = {
     // If Cu is defined, this file is loaded on the main thread. Otherwise, it
     // is loaded on the worker thread.
     if (Cu) {
-      DOMPromise.resolve().then(() => this.walkerLoop());
+      let stack = Components_ ? Components_.stack : null;
+      if (stack) {
+        DOMPromise.resolve().then(() => {
+          Cu.callFunctionWithAsyncStack(this.walkerLoop.bind(this), stack,
+                                        "Promise")
+        });
+      } else {
+        DOMPromise.resolve().then(() => this.walkerLoop());
+      }
     } else {
       setImmediate(this.walkerLoop);
     }