Bug 1560209 - Display original variables in WebAssembly when DWARF is provided. r=jlast

* Use XScopes data to display original varaibles (prototype)
* Move DWARF debugger logic to the separate package.

Differential Revision: https://phabricator.services.mozilla.com/D35367

--HG--
rename : devtools/client/debugger/packages/devtools-source-map/src/utils/convertToJSON.js => devtools/client/debugger/packages/devtools-wasm-dwarf/src/convertToJSON.js
rename : devtools/client/debugger/packages/devtools-source-map/wasm/dwarf_to_json.wasm => devtools/client/debugger/packages/devtools-wasm-dwarf/wasm/dwarf_to_json.wasm
extra : moz-landing-system : lando

devtools/client/debugger/bin/module-manifest.json

@@ -656,7 +656,14 @@
       "external \"\\n(() => { \\n  importScripts \\\"resource://devtools/client/shared/vendor/whatwg-url\\\";\\n  return { URL: self.URL }\\n})()\\n\"": 505,
       "external \"\\n(() => { \\n  importScripts(\\\"resource://devtools/client/shared/vendor/whatwg-url.js\\\");\\n  return { URL: self.URL }\\n})()\\n\"": 506,
       "external \"\\n(() => { \\n  importScripts(\\\"resource://devtools/client/shared/vendor/whatwg-url.js\\\");\\n  return { URL }\\n})()\\n\"": 507,
-      "external \"\\n(() => { \\n  console.log('>> yo',importScripts(\\\"resource://devtools/client/shared/vendor/whatwg-url.js\\\"));\\n  return { URL }\\n})()\\n\"": 508
+      "external \"\\n(() => { \\n  console.log('>> yo',importScripts(\\\"resource://devtools/client/shared/vendor/whatwg-url.js\\\"));\\n  return { URL }\\n})()\\n\"": 508,
+      "../../babel-loader/lib/index.js?ignore=src/lib!../../../packages/devtools-source-map/src/utils/wasmDwarfExpressions.js": 509,
+      "../../babel-loader/lib/index.js?ignore=src/lib!../../../packages/devtools-wasm-dwarf/index.js": 510,
+      "../../babel-loader/lib/index.js?ignore=src/lib!../../../packages/devtools-wasm-dwarf/src/wasmAssetBrowser.js": 511,
+      "../../babel-loader/lib/index.js?ignore=src/lib!../../../packages/devtools-wasm-dwarf/src/convertToJSON.js": 512,
+      "../../babel-loader/lib/index.js?ignore=src/lib!../../../packages/devtools-wasm-dwarf/src/wasmXScopes.js": 513,
+      "../../babel-loader/lib/index.js?ignore=src/lib!../../../packages/devtools-wasm-dwarf/src/wasmDwarfExpressions.js": 514,
+      "../../babel-loader/lib/index.js?ignore=src/lib!../../../packages/devtools-source-map/src/utils/assetRootBrowser.js": 515
     },
     "usedIds": {
       "0": 0,
@@ -1167,7 +1174,14 @@
       "505": 505,
       "506": 506,
       "507": 507,
-      "508": 508
+      "508": 508,
+      "509": 509,
+      "510": 510,
+      "511": 511,
+      "512": 512,
+      "513": 513,
+      "514": 514,
+      "515": 515
     }
   },
   "chunks": {

devtools/client/debugger/package.json

@@ -60,6 +60,7 @@
     "devtools-source-map": "0.16.0",
     "devtools-splitter": "^0.0.8",
     "devtools-utils": "0.0.14",
+    "devtools-wasm-dwarf": "0.0.1",
     "fuzzaldrin-plus": "^0.6.0",
     "lodash": "^4.17.4",
     "lodash-move": "^1.1.1",

devtools/client/debugger/packages/devtools-source-map/assets.js

@@ -4,6 +4,5 @@
 // @flow
 
 module.exports = {
-  "dwarf_to_json.wasm": require.resolve("./wasm/dwarf_to_json.wasm"),
   "source-map-mappings.wasm": require.resolve("source-map/lib/mappings.wasm"),
 };

devtools/client/debugger/packages/devtools-source-map/package.json

@@ -10,7 +10,7 @@
     "https://github.com/firefox-devtools/debugger/tree/master/packages/source-maps#readme",
   "main": "src/index.js",
   "browser": {
-    "./src/utils/wasmAsset.js": "./src/utils/wasmAssetBrowser.js"
+    "./src/utils/assetRoot.js": "./src/utils/assetRootBrowser.js"
   },
   "scripts": {
     "license-check": "devtools-license-check",
@@ -20,6 +20,7 @@
     "babel-plugin-transform-async-to-generator": "^6.22.0",
     "babel-plugin-transform-flow-strip-types": "^6.22.0",
     "devtools-utils": "0.0.14",
+    "devtools-wasm-dwarf": "0.0.1",
     "md5": "^2.2.1",
     "regenerator-runtime": "^0.13.0",
     "source-map": "0.8.0-beta.0"

devtools/client/debugger/packages/devtools-source-map/src/source-map.js

@@ -31,7 +31,7 @@ const {
   isOriginalId,
   getContentType,
 } = require("./utils");
-const { clearWasmXScopes } = require("./utils/wasmXScopes");
+const { clearWasmXScopes } = require("devtools-wasm-dwarf");
 
 import type { SourceLocation, Source, SourceId } from "debugger-html";
 

devtools/client/debugger/packages/devtools-source-map/src/utils/assetRoot.js

@@ -0,0 +1,12 @@
+/* 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/>. */
+// @flow
+
+function setAssetRootURL(assetRoot: string): void {
+  // No-op on Node
+}
+
+module.exports = {
+  setAssetRootURL,
+};

devtools/client/debugger/packages/devtools-source-map/src/utils/assetRootBrowser.js

@@ -0,0 +1,24 @@
+/* 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/>. */
+// @flow
+
+const { SourceMapConsumer } = require("source-map");
+const {
+  setAssetRootURL: wasmDwarfSetAssetRootURL,
+} = require("devtools-wasm-dwarf");
+
+function setAssetRootURL(assetRoot: string): void {
+  // Remove any trailing slash so we don't generate a double-slash below.
+  const root = assetRoot.replace(/\/$/, "");
+
+  wasmDwarfSetAssetRootURL(root);
+
+  SourceMapConsumer.initialize({
+    "lib/mappings.wasm": `${root}/source-map-mappings.wasm`,
+  });
+}
+
+module.exports = {
+  setAssetRootURL,
+};

devtools/client/debugger/packages/devtools-source-map/src/utils/fetchSourceMap.js

@@ -8,7 +8,7 @@ const { networkRequest } = require("devtools-utils");
 const { getSourceMap, setSourceMap } = require("./sourceMapRequests");
 const { WasmRemap } = require("./wasmRemap");
 const { SourceMapConsumer } = require("source-map");
-const { convertToJSON } = require("./convertToJSON");
+const { convertToJSON } = require("devtools-wasm-dwarf");
 const { createConsumer } = require("./createConsumer");
 
 import type { Source } from "debugger-html";

devtools/client/debugger/packages/devtools-source-map/src/utils/getOriginalStackFrames.js

@@ -6,14 +6,19 @@
 
 import type { OriginalFrame, SourceLocation } from "debugger-html";
 
-const { getWasmXScopes } = require("./wasmXScopes");
+const { getWasmXScopes } = require("devtools-wasm-dwarf");
+const { getSourceMap } = require("./sourceMapRequests");
+const { generatedToOriginalId } = require("./index");
 
 // Returns expanded stack frames details based on the generated location.
 // The function return null if not information was found.
 async function getOriginalStackFrames(
   generatedLocation: SourceLocation
 ): Promise<?Array<OriginalFrame>> {
-  const wasmXScopes = await getWasmXScopes(generatedLocation.sourceId);
+  const wasmXScopes = await getWasmXScopes(generatedLocation.sourceId, {
+    getSourceMap,
+    generatedToOriginalId,
+  });
   if (!wasmXScopes) {
     return null;
   }

devtools/client/debugger/packages/devtools-source-map/src/worker.js

@@ -21,7 +21,7 @@ const {
 } = require("./source-map");
 
 const { getOriginalStackFrames } = require("./utils/getOriginalStackFrames");
-const { setAssetRootURL } = require("./utils/wasmAsset");
+const { setAssetRootURL } = require("./utils/assetRoot");
 
 const {
   workerUtils: { workerHandler },

devtools/client/debugger/packages/devtools-wasm-dwarf/LICENSE

@@ -0,0 +1,362 @@
+Mozilla Public License, version 2.0
+
+1. Definitions
+
+1.1. "Contributor"
+
+     means each individual or legal entity that creates, contributes to the
+     creation of, or owns Covered Software.
+
+1.2. "Contributor Version"
+
+     means the combination of the Contributions of others (if any) used by a
+     Contributor and that particular Contributor's Contribution.
+
+1.3. "Contribution"
+
+     means Covered Software of a particular Contributor.
+
+1.4. "Covered Software"
+
+     means Source Code Form to which the initial Contributor has attached the
+     notice in Exhibit A, the Executable Form of such Source Code Form, and
+     Modifications of such Source Code Form, in each case including portions
+     thereof.
+
+1.5. "Incompatible With Secondary Licenses"
+     means
+
+     a. that the initial Contributor has attached the notice described in
+        Exhibit B to the Covered Software; or
+
+     b. that the Covered Software was made available under the terms of
+        version 1.1 or earlier of the License, but not also under the terms of
+        a Secondary License.
+
+1.6. "Executable Form"
+
+     means any form of the work other than Source Code Form.
+
+1.7. "Larger Work"
+
+     means a work that combines Covered Software with other material, in a
+     separate file or files, that is not Covered Software.
+
+1.8. "License"
+
+     means this document.
+
+1.9. "Licensable"
+
+     means having the right to grant, to the maximum extent possible, whether
+     at the time of the initial grant or subsequently, any and all of the
+     rights conveyed by this License.
+
+1.10. "Modifications"
+
+     means any of the following:
+
+     a. any file in Source Code Form that results from an addition to,
+        deletion from, or modification of the contents of Covered Software; or
+
+     b. any new file in Source Code Form that contains any Covered Software.
+
+1.11. "Patent Claims" of a Contributor
+
+      means any patent claim(s), including without limitation, method,
+      process, and apparatus claims, in any patent Licensable by such
+      Contributor that would be infringed, but for the grant of the License,
+      by the making, using, selling, offering for sale, having made, import,
+      or transfer of either its Contributions or its Contributor Version.
+
+1.12. "Secondary License"
+
+      means either the GNU General Public License, Version 2.0, the GNU Lesser
+      General Public License, Version 2.1, the GNU Affero General Public
+      License, Version 3.0, or any later versions of those licenses.
+
+1.13. "Source Code Form"
+
+      means the form of the work preferred for making modifications.
+
+1.14. "You" (or "Your")
+
+      means an individual or a legal entity exercising rights under this
+      License. For legal entities, "You" includes any entity that controls, is
+      controlled by, or is under common control with You. For purposes of this
+      definition, "control" means (a) the power, direct or indirect, to cause
+      the direction or management of such entity, whether by contract or
+      otherwise, or (b) ownership of more than fifty percent (50%) of the
+      outstanding shares or beneficial ownership of such entity.
+
+
+2. License Grants and Conditions
+
+2.1. Grants
+
+     Each Contributor hereby grants You a world-wide, royalty-free,
+     non-exclusive license:
+
+     a. under intellectual property rights (other than patent or trademark)
+        Licensable by such Contributor to use, reproduce, make available,
+        modify, display, perform, distribute, and otherwise exploit its
+        Contributions, either on an unmodified basis, with Modifications, or
+        as part of a Larger Work; and
+
+     b. under Patent Claims of such Contributor to make, use, sell, offer for
+        sale, have made, import, and otherwise transfer either its
+        Contributions or its Contributor Version.
+
+2.2. Effective Date
+
+     The licenses granted in Section 2.1 with respect to any Contribution
+     become effective for each Contribution on the date the Contributor first
+     distributes such Contribution.
+
+2.3. Limitations on Grant Scope
+
+     The licenses granted in this Section 2 are the only rights granted under
+     this License. No additional rights or licenses will be implied from the
+     distribution or licensing of Covered Software under this License.
+     Notwithstanding Section 2.1(b) above, no patent license is granted by a
+     Contributor:
+
+     a. for any code that a Contributor has removed from Covered Software; or
+
+     b. for infringements caused by: (i) Your and any other third party's
+        modifications of Covered Software, or (ii) the combination of its
+        Contributions with other software (except as part of its Contributor
+        Version); or
+
+     c. under Patent Claims infringed by Covered Software in the absence of
+        its Contributions.
+
+     This License does not grant any rights in the trademarks, service marks,
+     or logos of any Contributor (except as may be necessary to comply with
+     the notice requirements in Section 3.4).
+
+2.4. Subsequent Licenses
+
+     No Contributor makes additional grants as a result of Your choice to
+     distribute the Covered Software under a subsequent version of this
+     License (see Section 10.2) or under the terms of a Secondary License (if
+     permitted under the terms of Section 3.3).
+
+2.5. Representation
+
+     Each Contributor represents that the Contributor believes its
+     Contributions are its original creation(s) or it has sufficient rights to
+     grant the rights to its Contributions conveyed by this License.
+
+2.6. Fair Use
+
+     This License is not intended to limit any rights You have under
+     applicable copyright doctrines of fair use, fair dealing, or other
+     equivalents.
+
+2.7. Conditions
+
+     Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted in
+     Section 2.1.
+
+
+3. Responsibilities
+
+3.1. Distribution of Source Form
+
+     All distribution of Covered Software in Source Code Form, including any
+     Modifications that You create or to which You contribute, must be under
+     the terms of this License. You must inform recipients that the Source
+     Code Form of the Covered Software is governed by the terms of this
+     License, and how they can obtain a copy of this License. You may not
+     attempt to alter or restrict the recipients' rights in the Source Code
+     Form.
+
+3.2. Distribution of Executable Form
+
+     If You distribute Covered Software in Executable Form then:
+
+     a. such Covered Software must also be made available in Source Code Form,
+        as described in Section 3.1, and You must inform recipients of the
+        Executable Form how they can obtain a copy of such Source Code Form by
+        reasonable means in a timely manner, at a charge no more than the cost
+        of distribution to the recipient; and
+
+     b. You may distribute such Executable Form under the terms of this
+        License, or sublicense it under different terms, provided that the
+        license for the Executable Form does not attempt to limit or alter the
+        recipients' rights in the Source Code Form under this License.
+
+3.3. Distribution of a Larger Work
+
+     You may create and distribute a Larger Work under terms of Your choice,
+     provided that You also comply with the requirements of this License for
+     the Covered Software. If the Larger Work is a combination of Covered
+     Software with a work governed by one or more Secondary Licenses, and the
+     Covered Software is not Incompatible With Secondary Licenses, this
+     License permits You to additionally distribute such Covered Software
+     under the terms of such Secondary License(s), so that the recipient of
+     the Larger Work may, at their option, further distribute the Covered
+     Software under the terms of either this License or such Secondary
+     License(s).
+
+3.4. Notices
+
+     You may not remove or alter the substance of any license notices
+     (including copyright notices, patent notices, disclaimers of warranty, or
+     limitations of liability) contained within the Source Code Form of the
+     Covered Software, except that You may alter any license notices to the
+     extent required to remedy known factual inaccuracies.
+
+3.5. Application of Additional Terms
+
+     You may choose to offer, and to charge a fee for, warranty, support,
+     indemnity or liability obligations to one or more recipients of Covered
+     Software. However, You may do so only on Your own behalf, and not on
+     behalf of any Contributor. You must make it absolutely clear that any
+     such warranty, support, indemnity, or liability obligation is offered by
+     You alone, and You hereby agree to indemnify every Contributor for any
+     liability incurred by such Contributor as a result of warranty, support,
+     indemnity or liability terms You offer. You may include additional
+     disclaimers of warranty and limitations of liability specific to any
+     jurisdiction.
+
+4. Inability to Comply Due to Statute or Regulation
+
+   If it is impossible for You to comply with any of the terms of this License
+   with respect to some or all of the Covered Software due to statute,
+   judicial order, or regulation then You must: (a) comply with the terms of
+   this License to the maximum extent possible; and (b) describe the
+   limitations and the code they affect. Such description must be placed in a
+   text file included with all distributions of the Covered Software under
+   this License. Except to the extent prohibited by statute or regulation,
+   such description must be sufficiently detailed for a recipient of ordinary
+   skill to be able to understand it.
+
+5. Termination
+
+5.1. The rights granted under this License will terminate automatically if You
+     fail to comply with any of its terms. However, if You become compliant,
+     then the rights granted under this License from a particular Contributor
+     are reinstated (a) provisionally, unless and until such Contributor
+     explicitly and finally terminates Your grants, and (b) on an ongoing
+     basis, if such Contributor fails to notify You of the non-compliance by
+     some reasonable means prior to 60 days after You have come back into
+     compliance. Moreover, Your grants from a particular Contributor are
+     reinstated on an ongoing basis if such Contributor notifies You of the
+     non-compliance by some reasonable means, this is the first time You have
+     received notice of non-compliance with this License from such
+     Contributor, and You become compliant prior to 30 days after Your receipt
+     of the notice.
+
+5.2. If You initiate litigation against any entity by asserting a patent
+     infringement claim (excluding declaratory judgment actions,
+     counter-claims, and cross-claims) alleging that a Contributor Version
+     directly or indirectly infringes any patent, then the rights granted to
+     You by any and all Contributors for the Covered Software under Section
+     2.1 of this License shall terminate.
+
+5.3. In the event of termination under Sections 5.1 or 5.2 above, all end user
+     license agreements (excluding distributors and resellers) which have been
+     validly granted by You or Your distributors under this License prior to
+     termination shall survive termination.
+
+6. Disclaimer of Warranty
+
+   Covered Software is provided under this License on an "as is" basis,
+   without warranty of any kind, either expressed, implied, or statutory,
+   including, without limitation, warranties that the Covered Software is free
+   of defects, merchantable, fit for a particular purpose or non-infringing.
+   The entire risk as to the quality and performance of the Covered Software
+   is with You. Should any Covered Software prove defective in any respect,
+   You (not any Contributor) assume the cost of any necessary servicing,
+   repair, or correction. This disclaimer of warranty constitutes an essential
+   part of this License. No use of  any Covered Software is authorized under
+   this License except under this disclaimer.
+
+7. Limitation of Liability
+
+   Under no circumstances and under no legal theory, whether tort (including
+   negligence), contract, or otherwise, shall any Contributor, or anyone who
+   distributes Covered Software as permitted above, be liable to You for any
+   direct, indirect, special, incidental, or consequential damages of any
+   character including, without limitation, damages for lost profits, loss of
+   goodwill, work stoppage, computer failure or malfunction, or any and all
+   other commercial damages or losses, even if such party shall have been
+   informed of the possibility of such damages. This limitation of liability
+   shall not apply to liability for death or personal injury resulting from
+   such party's negligence to the extent applicable law prohibits such
+   limitation. Some jurisdictions do not allow the exclusion or limitation of
+   incidental or consequential damages, so this exclusion and limitation may
+   not apply to You.
+
+8. Litigation
+
+   Any litigation relating to this License may be brought only in the courts
+   of a jurisdiction where the defendant maintains its principal place of
+   business and such litigation shall be governed by laws of that
+   jurisdiction, without reference to its conflict-of-law provisions. Nothing
+   in this Section shall prevent a party's ability to bring cross-claims or
+   counter-claims.
+
+9. Miscellaneous
+
+   This License represents the complete agreement concerning the subject
+   matter hereof. If any provision of this License is held to be
+   unenforceable, such provision shall be reformed only to the extent
+   necessary to make it enforceable. Any law or regulation which provides that
+   the language of a contract shall be construed against the drafter shall not
+   be used to construe this License against a Contributor.
+
+
+10. Versions of the License
+
+10.1. New Versions
+
+      Mozilla Foundation is the license steward. Except as provided in Section
+      10.3, no one other than the license steward has the right to modify or
+      publish new versions of this License. Each version will be given a
+      distinguishing version number.
+
+10.2. Effect of New Versions
+
+      You may distribute the Covered Software under the terms of the version
+      of the License under which You originally received the Covered Software,
+      or under the terms of any subsequent version published by the license
+      steward.
+
+10.3. Modified Versions
+
+      If you create software not governed by this License, and you want to
+      create a new license for such software, you may create and use a
+      modified version of this License if you rename the license and remove
+      any references to the name of the license steward (except to note that
+      such modified license differs from this License).
+
+10.4. Distributing Source Code Form that is Incompatible With Secondary
+      Licenses If You choose to distribute Source Code Form that is
+      Incompatible With Secondary Licenses under the terms of this version of
+      the License, the notice described in Exhibit B of this License must be
+      attached.
+
+Exhibit A - Source Code Form License Notice
+
+      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/.
+
+If it is not possible or desirable to put the notice in a particular file,
+then You may include the notice in a location (such as a LICENSE file in a
+relevant directory) where a recipient would be likely to look for such a
+notice.
+
+You may add additional accurate notices of copyright ownership.
+
+Exhibit B - "Incompatible With Secondary Licenses" Notice
+
+      This Source Code Form is "Incompatible
+      With Secondary Licenses", as defined by
+      the Mozilla Public License, v. 2.0.

devtools/client/debugger/packages/devtools-wasm-dwarf/README.md

@@ -0,0 +1,4 @@
+## Devtools Utils
+
+* _networkRequest_ - CORS network requests
+* _workerUtils_ - worker task communication

devtools/client/debugger/packages/devtools-wasm-dwarf/assets.js

@@ -0,0 +1,8 @@
+/* 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/>. */
+// @flow
+
+module.exports = {
+  "dwarf_to_json.wasm": require.resolve("./wasm/dwarf_to_json.wasm"),
+};

devtools/client/debugger/packages/devtools-wasm-dwarf/index.js

@@ -0,0 +1,14 @@
+/* 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/>. */
+
+const { convertToJSON } = require("./src/convertToJSON");
+const { setAssetRootURL } = require("./src/wasmAsset");
+const { getWasmXScopes, clearWasmXScopes } = require("./src/wasmXScopes");
+
+module.exports = {
+  convertToJSON,
+  setAssetRootURL,
+  getWasmXScopes,
+  clearWasmXScopes,
+};

devtools/client/debugger/packages/devtools-wasm-dwarf/package.json

@@ -0,0 +1,19 @@
+{
+  "name": "devtools-wasm-dwarf",
+  "version": "0.0.1",
+  "description": "DevTools WebAssembly DWARF library",
+  "main": "index.js",
+  "scripts": {
+    "license-check": "devtools-license-check",
+    "test": ""
+  },
+  "browser": {
+    "./src/wasmAsset.js": "./src/wasmAssetBrowser.js"
+  },
+  "author": "",
+  "license": "MPL-2.0",
+  "dependencies": {
+    "babel-plugin-transform-flow-strip-types": "^6.22.0",
+    "babel-preset-stage-3": "^6.22.0"
+  }
+}

devtools/client/debugger/packages/devtools-wasm-dwarf/src/wasmAsset.js

@@ -5,7 +5,7 @@
 
 const fs = require("fs");
 
-const assets = require("../../assets");
+const assets = require("../assets");
 
 function setAssetRootURL(assetRoot: string): void {
   // No-op on Node

devtools/client/debugger/packages/devtools-wasm-dwarf/src/wasmAssetBrowser.js

@@ -3,16 +3,9 @@
  * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
 // @flow
 
-const { SourceMapConsumer } = require("source-map");
-
 let root;
 function setAssetRootURL(assetRoot: string): void {
-  // Remove any trailing slash so we don't generate a double-slash below.
-  root = assetRoot.replace(/\/$/, "");
-
-  SourceMapConsumer.initialize({
-    "lib/mappings.wasm": `${root}/source-map-mappings.wasm`,
-  });
+  root = assetRoot;
 }
 
 async function getDwarfToWasmData(name: string): Promise<ArrayBuffer> {

devtools/client/debugger/packages/devtools-wasm-dwarf/src/wasmDwarfExpressions.js

@@ -0,0 +1,263 @@
+/* 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/>. */
+
+// @flow
+/* eslint camelcase: 0*/
+/* eslint-disable no-inline-comments */
+
+type Expr = string;
+
+class Value {
+  val: Object;
+
+  constructor(val: Object) {
+    this.val = val;
+  }
+  toString() {
+    return `${this.val}`;
+  }
+}
+
+const Int32Formatter = {
+  fromAddr(addr) {
+    return `(new DataView(memory0.buffer).getInt32(${addr}, true))`;
+  },
+  fromValue(value) {
+    return `${value.val}`;
+  },
+};
+
+const Uint32Formatter = {
+  fromAddr(addr) {
+    return `(new DataView(memory0.buffer).getUint32(${addr}, true))`;
+  },
+  fromValue(value) {
+    return `(${value.val} >>> 0)`;
+  },
+};
+
+function createPieceFormatter(bytes) {
+  let getter;
+  switch (bytes) {
+    case 0:
+    case 1:
+      getter = "getUint8";
+      break;
+    case 2:
+      getter = "getUint16";
+      break;
+    case 3:
+    case 4:
+    default:
+      // FIXME 64-bit
+      getter = "getUint32";
+      break;
+  }
+  const mask = (1 << (8 * bytes)) - 1;
+  return {
+    fromAddr(addr) {
+      return `(new DataView(memory0.buffer).${getter}(${addr}, true))`;
+    },
+    fromValue(value) {
+      return `((${value.val} & ${mask}) >>> 0)`;
+    },
+  };
+}
+
+// eslint-disable-next-line complexity
+function toJS(buf, typeFormatter, frame_base = "fp()") {
+  const readU8 = function() {
+    return buf[i++];
+  };
+  const readS8 = function() {
+    return (readU8() << 24) >> 24;
+  };
+  const readU16 = function() {
+    const w = buf[i] | (buf[i + 1] << 8);
+    i += 2;
+    return w;
+  };
+  const readS16 = function() {
+    return (readU16() << 16) >> 16;
+  };
+  const readS32 = function() {
+    const w =
+      buf[i] | (buf[i + 1] << 8) | (buf[i + 2] << 16) | (buf[i + 3] << 24);
+    i += 4;
+    return w;
+  };
+  const readU32 = function() {
+    return readS32() >>> 0;
+  };
+  const readU = function() {
+    let n = 0,
+      shift = 0,
+      b;
+    while ((b = readU8()) & 0x80) {
+      n |= (b & 0x7f) << shift;
+      shift += 7;
+    }
+    return n | (b << shift);
+  };
+  const readS = function() {
+    let n = 0,
+      shift = 0,
+      b;
+    while ((b = readU8()) & 0x80) {
+      n |= (b & 0x7f) << shift;
+      shift += 7;
+    }
+    n |= b << shift;
+    shift += 7;
+    return shift > 32 ? (n << (32 - shift)) >> (32 - shift) : n;
+  };
+  const popValue = function(formatter) {
+    const loc = stack.pop();
+    if (loc instanceof Value) {
+      return formatter.fromValue(loc);
+    }
+    return formatter.fromAddr(loc);
+  };
+  let i = 0,
+    a,
+    b;
+  const stack: Array<Object> = [frame_base];
+  while (i < buf.length) {
+    const code = buf[i++];
+    switch (code) {
+      case 0x03 /* DW_OP_addr */:
+        stack.push(Uint32Formatter.fromAddr(readU32()));
+        break;
+      case 0x08 /* DW_OP_const1u 0x08 1 1-byte constant */:
+        stack.push(readU8());
+        break;
+      case 0x09 /* DW_OP_const1s 0x09 1 1-byte constant */:
+        stack.push(readS8());
+        break;
+      case 0x0a /* DW_OP_const2u 0x0a 1 2-byte constant */:
+        stack.push(readU16());
+        break;
+      case 0x0b /* DW_OP_const2s 0x0b 1 2-byte constant */:
+        stack.push(readS16());
+        break;
+      case 0x0c /* DW_OP_const2u 0x0a 1 2-byte constant */:
+        stack.push(readU32());
+        break;
+      case 0x0d /* DW_OP_const2s 0x0b 1 2-byte constant */:
+        stack.push(readS32());
+        break;
+      case 0x10 /* DW_OP_constu 0x10 1 ULEB128 constant */:
+        stack.push(readU());
+        break;
+      case 0x11 /* DW_OP_const2s 0x0b 1 2-byte constant */:
+        stack.push(readS());
+        break;
+
+      case 0x1c /* DW_OP_minus */:
+        b = stack.pop();
+        a = stack.pop();
+        stack.push(`${a} - ${b}`);
+        break;
+
+      case 0x22 /* DW_OP_plus */:
+        b = stack.pop();
+        a = stack.pop();
+        stack.push(`${a} + ${b}`);
+        break;
+
+      case 0x23 /* DW_OP_plus_uconst */:
+        b = readU();
+        a = stack.pop();
+        stack.push(`${a} + ${b}`);
+        break;
+
+      case 0x30 /* DW_OP_lit0 */:
+      case 0x31:
+      case 0x32:
+      case 0x33:
+      case 0x34:
+      case 0x35:
+      case 0x36:
+      case 0x37:
+      case 0x38:
+      case 0x39:
+      case 0x3a:
+      case 0x3b:
+      case 0x3c:
+      case 0x3d:
+      case 0x3e:
+      case 0x3f:
+      case 0x40:
+      case 0x41:
+      case 0x42:
+      case 0x43:
+      case 0x44:
+      case 0x45:
+      case 0x46:
+      case 0x47:
+      case 0x48:
+      case 0x49:
+      case 0x4a:
+      case 0x4b:
+      case 0x4c:
+      case 0x4d:
+      case 0x4e:
+      case 0x4f:
+        stack.push(`${code - 0x30}`);
+        break;
+
+      case 0x93 /* DW_OP_piece */: {
+        a = readU();
+        const formatter = createPieceFormatter(a);
+        stack.push(popValue(formatter));
+        break;
+      }
+
+      case 0x9f /* DW_OP_stack_value */:
+        stack.push(new Value(stack.pop()));
+        break;
+
+      case 0xf6 /* WASM ext (old, FIXME phase out) */:
+      case 0xed /* WASM ext */:
+        b = readU();
+        a = readS();
+        switch (b) {
+          case 0:
+            stack.push(`var${a}`);
+            break;
+          case 1:
+            stack.push(`global${a}`);
+            break;
+          default:
+            stack.push(`ti${b}(${a})`);
+            break;
+        }
+        break;
+
+      default:
+        // Unknown encoding, baling out
+        return null;
+    }
+  }
+  // FIXME use real DWARF type information
+  return popValue(typeFormatter);
+}
+
+function decodeExpr(expr: string): Expr {
+  if (expr.includes("//")) {
+    expr = expr.slice(0, expr.indexOf("//")).trim();
+  }
+  const code = new Uint8Array(expr.length >> 1);
+  for (let i = 0; i < code.length; i++) {
+    code[i] = parseInt(expr.substr(i << 1, 2), 16);
+  }
+  const typeFormatter = Int32Formatter;
+  return toJS(code, typeFormatter) || `dwarf("${expr}")`;
+}
+
+export type { Expr };
+
+module.exports = {
+  decodeExpr,
+};

devtools/client/debugger/packages/devtools-wasm-dwarf/src/wasmXScopes.js

@@ -6,15 +6,25 @@
 /* eslint camelcase: 0*/
 
 import type { OriginalFrame, SourceLocation, SourceId } from "debugger-html";
+import type { Expr } from "./wasmDwarfExpressions";
 
-const { getSourceMap } = require("./sourceMapRequests");
-const { generatedToOriginalId } = require("./index");
+const { decodeExpr } = require("./wasmDwarfExpressions");
 
 const xScopes = new Map();
 
 type XScopeItem = any;
 type XScopeItemsIndex = Map<string | number, XScopeItem>;
 
+type XScopeVariable = {
+  name: string,
+  expr?: Expr,
+};
+
+type XScopeVariables = {
+  vars: XScopeVariable[],
+  frameBase?: Expr | null,
+};
+
 function indexLinkingNames(items: XScopeItem[]): XScopeItemsIndex {
   const result = new Map();
   let queue = [...items];
@@ -54,7 +64,15 @@ type XScopeData = {
   sources: Array<string>,
 };
 
-async function getXScopes(sourceId: SourceId): Promise<?XScopeData> {
+async function getXScopes(
+  sourceId: SourceId,
+  getSourceMap: (
+    sourceId: SourceId
+  ) => {
+    sources: string[],
+    xScopes?: XScopeData,
+  }
+): Promise<?XScopeData> {
   if (xScopes.has(sourceId)) {
     return xScopes.get(sourceId);
   }
@@ -87,10 +105,53 @@ function isInRange(item: XScopeItem, pc: number): boolean {
 type FoundScope = {
   id: string,
   name?: string,
+  variables: XScopeVariables,
   file?: number,
   line?: number,
 };
 
+type EncodedExpr =
+  | string
+  | Array<{
+      expr: string,
+      range: number[],
+    }>;
+
+function decodeExprAt(expr: EncodedExpr, pc: number): ?Expr {
+  if (typeof expr === "string") {
+    return decodeExpr(expr);
+  }
+  const foundAt = expr.find(i => i.range[0] <= pc && pc < i.range[1]);
+  return foundAt ? decodeExpr(foundAt.expr) : null;
+}
+
+function getVariables(scope: XScopeItem, pc: number): XScopeVariables {
+  const vars = scope.children
+    ? scope.children.reduce((result, item) => {
+        switch (item.tag) {
+          case "variable":
+          case "formal_parameter":
+            result.push({
+              name: item.name || "",
+              expr: item.location ? decodeExprAt(item.location, pc) : null,
+            });
+            break;
+          case "lexical_block":
+            // FIXME build scope blocks (instead of combining)
+            const tmp = getVariables(item, pc);
+            result = [...tmp.vars, ...result];
+            break;
+        }
+        return result;
+      }, [])
+    : [];
+  const frameBase = scope.frame_base ? decodeExpr(scope.frame_base) : null;
+  return {
+    vars,
+    frameBase,
+  };
+}
+
 function filterScopes(
   items: XScopeItem[],
   pc: number,
@@ -123,6 +184,7 @@ function filterScopes(
           const s: FoundScope = {
             id: item.linkage_name,
             name: item.name,
+            variables: getVariables(item, pc),
           };
           result = [...result, s, ...filterScopes(item.children, pc, s, index)];
         }
@@ -133,6 +195,7 @@ function filterScopes(
           const s: FoundScope = {
             id: item.abstract_origin,
             name: linkedItem ? linkedItem.name : void 0,
+            variables: getVariables(item, pc),
           };
           if (lastItem) {
             lastItem.file = item.call_file;
@@ -146,11 +209,21 @@ function filterScopes(
   }, []);
 }
 
+interface XScopeSourceMapContext {
+  getSourceMap(sourceId: SourceId): any;
+  generatedToOriginalId(sourceId: SourceId, url: string): SourceId;
+}
+
 class XScope {
   xScope: XScopeData;
+  sourceMapContext: XScopeSourceMapContext;
 
-  constructor(xScopeData: XScopeData) {
+  constructor(
+    xScopeData: XScopeData,
+    sourceMapContext: XScopeSourceMapContext
+  ) {
     this.xScope = xScopeData;
+    this.sourceMapContext = sourceMapContext;
   }
 
   search(generatedLocation: SourceLocation): Array<OriginalFrame> {
@@ -163,14 +236,16 @@ class XScope {
       if (!("file" in i)) {
         return {
           displayName: i.name || "",
+          variables: i.variables,
         };
       }
-      const sourceId = generatedToOriginalId(
+      const sourceId = this.sourceMapContext.generatedToOriginalId(
         generatedLocation.sourceId,
         sources[i.file || 0]
       );
       return {
         displayName: i.name || "",
+        variables: i.variables,
         location: {
           line: i.line || 0,
           sourceId,
@@ -180,12 +255,16 @@ class XScope {
   }
 }
 
-async function getWasmXScopes(sourceId: SourceId): Promise<?XScope> {
-  const xScopeData = await getXScopes(sourceId);
+async function getWasmXScopes(
+  sourceId: SourceId,
+  sourceMapContext: XScopeSourceMapContext
+): Promise<?XScope> {
+  const { getSourceMap } = sourceMapContext;
+  const xScopeData = await getXScopes(sourceId, getSourceMap);
   if (!xScopeData) {
     return null;
   }
-  return new XScope(xScopeData);
+  return new XScope(xScopeData, sourceMapContext);
 }
 
 function clearWasmXScopes() {

devtools/client/debugger/src/actions/pause/mapFrames.js

@@ -156,6 +156,7 @@ async function expandFrames(
         // updateFrameLocation.
         generatedLocation: frame.generatedLocation,
         originalDisplayName: originalFrame.displayName,
+        originalVariables: originalFrame.variables,
       });
     });
   }

devtools/client/debugger/src/actions/pause/mapScopes.js

@@ -5,6 +5,7 @@
 // @flow
 
 import {
+  getSelectedFrameId,
   getSource,
   getSourceContent,
   isMapScopesEnabled,
@@ -19,13 +20,67 @@ import assert from "../../utils/assert";
 
 import { log } from "../../utils/log";
 import { isGenerated, isOriginal } from "../../utils/source";
-import type { Frame, Scope, ThreadContext } from "../../types";
+import type { Frame, Scope, ThreadContext, XScopeVariables } from "../../types";
 
 import type { ThunkArgs } from "../types";
 
 import { buildMappedScopes } from "../../utils/pause/mapScopes";
 import { isFulfilled } from "../../utils/async-value";
 
+import type { OriginalScope } from "../../utils/pause/mapScopes";
+
+export async function buildOriginalScopes(
+  frame: Frame,
+  client: any,
+  cx: ThreadContext,
+  frameId: any,
+  generatedScopes: Promise<Scope>
+): Promise<?{
+  mappings: {
+    [string]: string,
+  },
+  scope: OriginalScope,
+}> {
+  if (!frame.originalVariables) {
+    throw new TypeError("(frame.originalVariables: XScopeVariables)");
+  }
+  const originalVariables: XScopeVariables = frame.originalVariables;
+  const frameBase = originalVariables.frameBase || "";
+  const inputs = [];
+  for (let i = 0; i < originalVariables.vars.length; i++) {
+    const expr = originalVariables.vars[i].expr || "void 0";
+    inputs[i] = expr.replace(/\bfp\(\)/g, frameBase);
+  }
+  const results = await client.evaluateExpressions(inputs, {
+    frameId,
+    thread: cx.thread,
+  });
+
+  const variables = {};
+  for (let i = 0; i < originalVariables.vars.length; i++) {
+    const name = originalVariables.vars[i].name;
+    variables[name] = { value: results[i].result };
+    console.log("!Variable", name, inputs[i]);
+  }
+  const bindings = {
+    arguments: [],
+    variables,
+  };
+  const actor = (await generatedScopes).actor;
+  const scope = {
+    type: "function",
+    actor,
+    bindings,
+    parent: null,
+    function: null,
+    block: null,
+  };
+  return {
+    mappings: {},
+    scope,
+  };
+}
+
 export function toggleMapScopes() {
   return async function({ dispatch, getState, client, sourceMaps }: ThunkArgs) {
     if (isMapScopesEnabled(getState())) {
@@ -56,7 +111,7 @@ export function mapScopes(
   frame: Frame
 ) {
   return async function(thunkArgs: ThunkArgs) {
-    const { dispatch, getState } = thunkArgs;
+    const { dispatch, client, getState } = thunkArgs;
     assert(cx.thread == frame.thread, "Thread mismatch");
 
     const generatedSource = getSource(
@@ -72,6 +127,11 @@ export function mapScopes(
       thread: cx.thread,
       frame,
       [PROMISE]: (async function() {
+        if (frame.isOriginal && frame.originalVariables) {
+          const frameId = getSelectedFrameId(getState(), cx.thread);
+          return buildOriginalScopes(frame, client, cx, frameId, scopes);
+        }
+
         if (
           !isMapScopesEnabled(getState()) ||
           !source ||

devtools/client/debugger/src/types.js

@@ -210,6 +210,18 @@ export type PendingBreakpoint = {
  */
 export type FrameId = string;
 
+type Expr = string;
+
+export type XScopeVariable = {
+  name: string,
+  expr?: Expr,
+};
+
+export type XScopeVariables = {
+  vars: XScopeVariable[],
+  frameBase?: Expr | null,
+};
+
 /**
  * Frame
  * @memberof types
@@ -228,6 +240,7 @@ export type Frame = {
   framework?: string,
   isOriginal?: boolean,
   originalDisplayName?: string,
+  originalVariables?: XScopeVariables,
   library?: string,
 };
 
@@ -241,6 +254,7 @@ export type ChromeFrame = {
 
 export type OriginalFrame = {
   displayName: string,
+  variables?: Object,
   location?: SourceLocation,
   thread: string,
 };