--- a/addon-sdk/test/browser.ini
+++ b/addon-sdk/test/browser.ini
@@ -2,14 +2,13 @@
 support-files =
   head.js
   Math.jsm
   math.js
   data.json
   invalid.json
 [browser_sdk_loader_sdk_modules.js]
 [browser_sdk_loader_sdk_gui_modules.js]
-skip-if = e10s # Bug 1315042
 [browser_sdk_loader_jsm_modules.js]
 [browser_sdk_loader_js_modules.js]
 [browser_sdk_loader_json.js]
 [browser_sdk_loader_chrome.js]
 [browser_sdk_loader_chrome_in_sdk.js]

--- a/browser/base/content/test/plugins/browser.ini
+++ b/browser/base/content/test/plugins/browser.ini
@@ -51,17 +51,16 @@ skip-if = toolkit == "gtk2" || toolkit =
 [browser_CTP_crashreporting.js]
 skip-if = !crashreporter
 [browser_CTP_data_urls.js]
 [browser_CTP_drag_drop.js]
 [browser_CTP_hide_overlay.js]
 [browser_CTP_iframe.js]
 [browser_CTP_multi_allow.js]
 [browser_CTP_nonplugins.js]
-skip-if = e10s # Bug 1315042
 [browser_CTP_notificationBar.js]
 [browser_CTP_outsideScrollArea.js]
 [browser_CTP_remove_navigate.js]
 [browser_CTP_resize.js]
 [browser_CTP_zoom.js]
 [browser_blocking.js]
 [browser_plugins_added_dynamically.js]
 [browser_pluginnotification.js]

--- a/browser/base/content/test/referrer/browser.ini
+++ b/browser/base/content/test/referrer/browser.ini
@@ -1,17 +1,16 @@
 [DEFAULT]
 support-files =
   file_referrer_policyserver.sjs
   file_referrer_policyserver_attr.sjs
   file_referrer_testserver.sjs
   head.js
 
 [browser_referrer_middle_click.js]
-skip-if = e10s # Bug 1315042
 [browser_referrer_middle_click_in_container.js]
 [browser_referrer_open_link_in_private.js]
 skip-if = os == 'linux' # Bug 1145199
 [browser_referrer_open_link_in_tab.js]
 skip-if = os == 'linux' # Bug 1144816
 [browser_referrer_open_link_in_window.js]
 skip-if = os == 'linux' # Bug 1145199
 [browser_referrer_open_link_in_window_in_container.js]

--- a/browser/base/content/test/webrtc/browser.ini
+++ b/browser/base/content/test/webrtc/browser.ini
@@ -4,9 +4,8 @@ support-files =
   get_user_media_content_script.js
   head.js
 
 [browser_devices_get_user_media.js]
 skip-if = (os == "linux" && debug) # linux: bug 976544
 [browser_devices_get_user_media_anim.js]
 [browser_devices_get_user_media_in_frame.js]
 [browser_devices_get_user_media_tear_off_tab.js]
-skip-if = e10s # Bug 1315042

--- a/browser/base/content/test/webrtc/browser_devices_get_user_media.js
+++ b/browser/base/content/test/webrtc/browser_devices_get_user_media.js
@@ -19,18 +19,19 @@ var gTests = [
     let promise = promisePopupNotificationShown("webRTC-shareDevices");
     yield promiseRequestDevice(true, true);
     yield promise;
     yield expectObserverCalled("getUserMedia:request");
 
     is(PopupNotifications.getNotification("webRTC-shareDevices").anchorID,
        "webRTC-shareDevices-notification-icon", "anchored to device icon");
     checkDeviceSelectors(true, true);
-    is(PopupNotifications.panel.firstChild.getAttribute("popupid"),
-       "webRTC-shareDevices", "panel using devices icon");
+    let iconclass =
+      PopupNotifications.panel.firstChild.getAttribute("iconclass");
+    ok(iconclass.includes("camera-icon"), "panel using devices icon");
 
     let indicator = promiseIndicatorWindow();
     yield promiseMessage("ok", () => {
       PopupNotifications.panel.firstChild.button.click();
     });
     yield expectObserverCalled("getUserMedia:response:allow");
     yield expectObserverCalled("recording-device-events");
     is((yield getMediaCaptureState()), "CameraAndMicrophone",
@@ -48,18 +49,19 @@ var gTests = [
     let promise = promisePopupNotificationShown("webRTC-shareDevices");
     yield promiseRequestDevice(true);
     yield promise;
     yield expectObserverCalled("getUserMedia:request");
 
     is(PopupNotifications.getNotification("webRTC-shareDevices").anchorID,
        "webRTC-shareMicrophone-notification-icon", "anchored to mic icon");
     checkDeviceSelectors(true);
-    is(PopupNotifications.panel.firstChild.getAttribute("popupid"),
-       "webRTC-shareMicrophone", "panel using microphone icon");
+    let iconclass =
+      PopupNotifications.panel.firstChild.getAttribute("iconclass");
+    ok(iconclass.includes("microphone-icon"), "panel using microphone icon");
 
     let indicator = promiseIndicatorWindow();
     yield promiseMessage("ok", () => {
       PopupNotifications.panel.firstChild.button.click();
     });
     yield expectObserverCalled("getUserMedia:response:allow");
     yield expectObserverCalled("recording-device-events");
     is((yield getMediaCaptureState()), "Microphone",
@@ -77,18 +79,19 @@ var gTests = [
     let promise = promisePopupNotificationShown("webRTC-shareDevices");
     yield promiseRequestDevice(false, true);
     yield promise;
     yield expectObserverCalled("getUserMedia:request");
 
     is(PopupNotifications.getNotification("webRTC-shareDevices").anchorID,
        "webRTC-shareDevices-notification-icon", "anchored to device icon");
     checkDeviceSelectors(false, true);
-    is(PopupNotifications.panel.firstChild.getAttribute("popupid"),
-       "webRTC-shareDevices", "panel using devices icon");
+    let iconclass =
+      PopupNotifications.panel.firstChild.getAttribute("iconclass");
+    ok(iconclass.includes("camera-icon"), "panel using devices icon");
 
     let indicator = promiseIndicatorWindow();
     yield promiseMessage("ok", () => {
       PopupNotifications.panel.firstChild.button.click();
     });
     yield expectObserverCalled("getUserMedia:response:allow");
     yield expectObserverCalled("recording-device-events");
     is((yield getMediaCaptureState()), "Camera", "expected camera to be shared");

new file mode 100644
--- /dev/null
+++ b/browser/docs/BrowserUsageTelemetry.rst
@@ -0,0 +1,28 @@
+.. _browserusagetelemetry:
+
+=======================
+Browser Usage Telemetry
+=======================
+
+The `BrowserUsageTelemetry.jsm <https://dxr.mozilla.org/mozilla-central/source/browser/modules/BrowserUsageTelemetry.jsm>`_ module is the main module for measurements regarding the browser usage (e.g. tab and window counts, search counts, ...).
+
+The measurements recording begins right after the ``SessionStore`` has finished restoring the session (i.e. restoring tabs/windows after Firefox starts).
+
+Search telemetry
+================
+This module exposes the ``recordSearch`` method, which serves as the main entry point for recording search related Telemetry. It records only the search *counts* per engine and the origin of the search, but nothing pertaining the search contents themselves.
+
+As the transition to the ``BrowserUsageTelemetry`` happens, the ``recordSearch`` calls are dispatched through `BrowserSearch.recordSearchInTelemetry <https://dxr.mozilla.org/mozilla-central/rev/3e73fd638e687a4d7f46613586e5156b8e2af846/browser/base/content/browser.js#3752>`_, that is called by all the search related UI components (urlbar, searchbar, context menu and about\:\* pages).
+
+A list of the components recording search Telemetry can be found using the following `DXR search <https://dxr.mozilla.org/mozilla-central/search?q=recordSearchInTelemetry>`_.
+
+Measured interactions
+=====================
+The usage telemetry module currently measures these interactions with the browser:
+
+- *tab and window engagement*: counts the number of non-private tabs and windows opened in a subsession, after the session is restored (see e.g. ``browser.engagement.max_concurrent_tab_count``);
+- *URI loads*: counts the number of page loads (doesn't track and send the addresses, just the counts) directly triggered by the users (see ``browser.engagement.total_uri_count``);
+- *navigation events*: at this time, this only counts the number of time a page load is triggered by a particular UI interaction (e.g. by searching through the URL bar, see ``browser.engagement.navigation.urlbar``).
+
+
+Please see `Scalars.yaml <https://dxr.mozilla.org/mozilla-central/source/toolkit/components/telemetry/Scalars.yaml>`_ for the full list of tracked interactions.

--- a/browser/docs/index.rst
+++ b/browser/docs/index.rst
@@ -4,8 +4,9 @@ Firefox
 
 This is the nascent documentation of the Firefox front-end code.
 
 .. toctree::
    :maxdepth: 1
 
    DirectoryLinksProvider
    UITelemetry
+   BrowserUsageTelemetry

--- a/browser/modules/webrtcUI.jsm
+++ b/browser/modules/webrtcUI.jsm
@@ -358,27 +358,16 @@ function prompt(aBrowser, aRequest) {
 
   let options = {
     eventCallback: function(aTopic, aNewBrowser) {
       if (aTopic == "swapping")
         return true;
 
       let chromeDoc = this.browser.ownerDocument;
 
-      if (aTopic == "shown") {
-        let popupId = "Devices";
-        if (requestTypes.length == 1 && (requestTypes[0] == "Microphone" ||
-                                         requestTypes[0] == "AudioCapture"))
-          popupId = "Microphone";
-        if (requestTypes.includes("Screen"))
-          popupId = "Screen";
-        chromeDoc.getElementById("webRTC-shareDevices-notification")
-                 .setAttribute("popupid", "webRTC-share" + popupId);
-      }
-
       // Clean-up video streams of screensharing previews.
       if ((aTopic == "dismissed" || aTopic == "removed") &&
           requestTypes.includes("Screen")) {
         let video = chromeDoc.getElementById("webRTC-previewVideo");
         video.deviceId = undefined;
         if (video.stream) {
           video.stream.getTracks().forEach(t => t.stop());
           video.stream = null;
@@ -666,21 +655,29 @@ function prompt(aBrowser, aRequest) {
         mm.sendAsyncMessage("webrtc:Allow", {callID: aRequest.callID,
                                              windowID: aRequest.windowID,
                                              devices: allowedDevices});
       };
       return false;
     }
   };
 
-  let anchorId = "webRTC-shareDevices-notification-icon";
-  if (requestTypes.length == 1 && requestTypes[0] == "Microphone")
-    anchorId = "webRTC-shareMicrophone-notification-icon";
+  let iconType = "Devices";
+  if (requestTypes.length == 1 && (requestTypes[0] == "Microphone" ||
+                                   requestTypes[0] == "AudioCapture"))
+    iconType = "Microphone";
   if (requestTypes.includes("Screen"))
-    anchorId = "webRTC-shareScreen-notification-icon";
+    iconType = "Screen";
+  let anchorId = "webRTC-share" + iconType + "-notification-icon";
+
+  let iconClass = iconType.toLowerCase();
+  if (iconClass == "devices")
+    iconClass = "camera";
+  options.popupIconClass = iconClass + "-icon";
+
   notification =
     chromeWin.PopupNotifications.show(aBrowser, "webRTC-shareDevices", message,
                                       anchorId, mainAction, secondaryActions,
                                       options);
   notification.callID = aRequest.callID;
 }
 
 function removePrompt(aBrowser, aCallId) {

--- a/browser/themes/shared/notification-icons.inc.css
+++ b/browser/themes/shared/notification-icons.inc.css
@@ -108,18 +108,17 @@
 .login-icon {
   list-style-image: url(chrome://browser/skin/notification-icons.svg#login);
 }
 
 .popup-notification-icon[popupid="password"] {
   list-style-image: url(chrome://browser/skin/notification-icons.svg#login-detailed);
 }
 
-.camera-icon,
-.popup-notification-icon[popupid="webRTC-shareDevices"] {
+.camera-icon {
   list-style-image: url(chrome://browser/skin/notification-icons.svg#camera);
 }
 
 .camera-icon.in-use {
   list-style-image: url(chrome://browser/skin/notification-icons.svg#camera-sharing);
 }
 
 .camera-icon.blocked-permission-icon {
@@ -133,21 +132,20 @@
 .microphone-icon.in-use {
   list-style-image: url(chrome://browser/skin/notification-icons.svg#microphone-sharing);
 }
 
 .microphone-icon.blocked-permission-icon {
   list-style-image: url(chrome://browser/skin/notification-icons.svg#microphone-blocked);
 }
 
-.popup-notification-icon[popupid="webRTC-shareMicrophone"] {
+.popup-notification-icon.microphone-icon {
   list-style-image: url(chrome://browser/skin/notification-icons.svg#microphone-detailed);
 }
 
-.popup-notification-icon[popupid="webRTC-shareScreen"],
 .screen-icon {
   list-style-image: url(chrome://browser/skin/notification-icons.svg#screen);
 }
 
 .screen-icon.in-use {
   list-style-image: url(chrome://browser/skin/notification-icons.svg#screen-sharing);
 }
 

--- a/build/valgrind/mach_commands.py
+++ b/build/valgrind/mach_commands.py
@@ -108,16 +108,19 @@ class MachCommands(MachCommandBase):
                 '--vex-iropt-register-updates=allregs-at-mem-access',
                 '--gen-suppressions=all',
                 '--num-callers=36',
                 '--leak-check=full',
                 '--show-possibly-lost=no',
                 '--track-origins=yes',
                 '--trace-children=yes',
                 '-v',  # Enable verbosity to get the list of used suppressions
+                # Avoid excessive delays in the presence of spinlocks.
+                # See bug 1309851.
+                '--fair-sched=yes',
             ]
 
             for s in suppressions:
                 valgrind_args.append('--suppressions=' + s)
 
             supps_dir = os.path.join(build_dir, 'valgrind')
             supps_file1 = os.path.join(supps_dir, 'cross-architecture.sup')
             valgrind_args.append('--suppressions=' + supps_file1)

--- a/caps/BasePrincipal.cpp
+++ b/caps/BasePrincipal.cpp
@@ -319,16 +319,17 @@ OriginAttributes::SetFromGenericAttribut
   mAppId = aAttrs.mAppId;
   mInIsolatedMozBrowser = aAttrs.mInIsolatedMozBrowser;
   mAddonId = aAttrs.mAddonId;
   mUserContextId = aAttrs.mUserContextId;
   mPrivateBrowsingId = aAttrs.mPrivateBrowsingId;
   mFirstPartyDomain = aAttrs.mFirstPartyDomain;
 }
 
+/* static */
 bool
 OriginAttributes::IsFirstPartyEnabled()
 {
   // Cache the privacy.firstparty.isolate pref.
   static bool sFirstPartyIsolation = false;
   static bool sCachedFirstPartyPref = false;
   if (!sCachedFirstPartyPref) {
     sCachedFirstPartyPref = true;

--- a/caps/BasePrincipal.h
+++ b/caps/BasePrincipal.h
@@ -56,23 +56,23 @@ public:
                           nsACString& aOriginNoSuffix);
 
   // Helper function to match mIsPrivateBrowsing to existing private browsing
   // flags. Once all other flags are removed, this can be removed too.
   void SyncAttributesWithPrivateBrowsing(bool aInPrivateBrowsing);
 
   void SetFromGenericAttributes(const GenericOriginAttributes& aAttrs);
 
+  // check if "privacy.firstparty.isolate" is enabled.
+  static bool IsFirstPartyEnabled();
+
 protected:
   OriginAttributes() {}
   explicit OriginAttributes(const OriginAttributesDictionary& aOther)
     : OriginAttributesDictionary(aOther) {}
-
-  // check if "privacy.firstparty.isolate" is enabled.
-  bool IsFirstPartyEnabled();
 };
 
 class PrincipalOriginAttributes;
 class DocShellOriginAttributes;
 class NeckoOriginAttributes;
 
 // Various classes in Gecko contain OriginAttributes members, and those
 // OriginAttributes get propagated to other classes according to certain rules.

--- a/devtools/client/aboutdebugging/components/aboutdebugging.js
+++ b/devtools/client/aboutdebugging/components/aboutdebugging.js
@@ -1,29 +1,34 @@
 /* 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/. */
 
 /* eslint-env browser */
 
 "use strict";
 
-const { createFactory, createClass, DOM: dom } =
+const { createFactory, createClass, DOM: dom, PropTypes } =
   require("devtools/client/shared/vendor/react");
 const Services = require("Services");
 
 const PanelMenu = createFactory(require("./panel-menu"));
 
 loader.lazyGetter(this, "AddonsPanel",
   () => createFactory(require("./addons/panel")));
 loader.lazyGetter(this, "TabsPanel",
   () => createFactory(require("./tabs/panel")));
 loader.lazyGetter(this, "WorkersPanel",
   () => createFactory(require("./workers/panel")));
 
+loader.lazyRequireGetter(this, "DebuggerClient",
+  "devtools/shared/client/main", true);
+loader.lazyRequireGetter(this, "Telemetry",
+  "devtools/client/shared/telemetry");
+
 const Strings = Services.strings.createBundle(
   "chrome://devtools/locale/aboutdebugging.properties");
 
 const panels = [{
   id: "addons",
   name: Strings.GetStringFromName("addons"),
   icon: "chrome://devtools/skin/images/debugging-addons.svg",
   component: AddonsPanel
@@ -39,16 +44,21 @@ const panels = [{
   component: WorkersPanel
 }];
 
 const defaultPanelId = "addons";
 
 module.exports = createClass({
   displayName: "AboutDebuggingApp",
 
+  propTypes: {
+    client: PropTypes.instanceOf(DebuggerClient).isRequired,
+    telemetry: PropTypes.instanceOf(Telemetry).isRequired
+  },
+
   getInitialState() {
     return {
       selectedPanelId: defaultPanelId
     };
   },
 
   componentDidMount() {
     window.addEventListener("hashchange", this.onHashChange);

--- a/devtools/client/aboutdebugging/components/addons/controls.js
+++ b/devtools/client/aboutdebugging/components/addons/controls.js
@@ -6,30 +6,34 @@
 /* globals AddonManager */
 
 "use strict";
 
 loader.lazyImporter(this, "AddonManager",
   "resource://gre/modules/AddonManager.jsm");
 
 const { Cc, Ci } = require("chrome");
-const { createFactory, createClass, DOM: dom } =
+const { createFactory, createClass, DOM: dom, PropTypes } =
   require("devtools/client/shared/vendor/react");
 const Services = require("Services");
 const AddonsInstallError = createFactory(require("./install-error"));
 
 const Strings = Services.strings.createBundle(
   "chrome://devtools/locale/aboutdebugging.properties");
 
 const MORE_INFO_URL = "https://developer.mozilla.org/docs/Tools" +
                       "/about:debugging#Enabling_add-on_debugging";
 
 module.exports = createClass({
   displayName: "AddonsControls",
 
+  propTypes: {
+    debugDisabled: PropTypes.bool
+  },
+
   getInitialState() {
     return {
       installError: null,
     };
   },
 
   onEnableAddonDebuggingChange(event) {
     let enabled = event.target.checked;

--- a/devtools/client/aboutdebugging/components/addons/install-error.js
+++ b/devtools/client/aboutdebugging/components/addons/install-error.js
@@ -1,20 +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/. */
 
 /* eslint-env browser */
 "use strict";
 
-const { createClass, DOM: dom } = require("devtools/client/shared/vendor/react");
+const { createClass, DOM: dom, PropTypes } = require("devtools/client/shared/vendor/react");
 
 module.exports = createClass({
   displayName: "AddonsInstallError",
 
+  propTypes: {
+    error: PropTypes.string
+  },
+
   render() {
     if (!this.props.error) {
       return null;
     }
     let text = `There was an error during installation: ${this.props.error}`;
     return dom.div({ className: "addons-install-error" },
                    dom.div({ className: "warning" }),
                    dom.span({}, text));

--- a/devtools/client/aboutdebugging/components/addons/panel.js
+++ b/devtools/client/aboutdebugging/components/addons/panel.js
@@ -1,34 +1,42 @@
 /* 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/. */
 
 "use strict";
 
 const { AddonManager } = require("resource://gre/modules/AddonManager.jsm");
-const { createFactory, createClass, DOM: dom } =
+const { createFactory, createClass, DOM: dom, PropTypes } =
   require("devtools/client/shared/vendor/react");
 const Services = require("Services");
 
 const AddonsControls = createFactory(require("./controls"));
 const AddonTarget = createFactory(require("./target"));
 const PanelHeader = createFactory(require("../panel-header"));
 const TargetList = createFactory(require("../target-list"));
 
+loader.lazyRequireGetter(this, "DebuggerClient",
+  "devtools/shared/client/main", true);
+
 const Strings = Services.strings.createBundle(
   "chrome://devtools/locale/aboutdebugging.properties");
 
 const ExtensionIcon = "chrome://mozapps/skin/extensions/extensionGeneric.svg";
 const CHROME_ENABLED_PREF = "devtools.chrome.enabled";
 const REMOTE_ENABLED_PREF = "devtools.debugger.remote-enabled";
 
 module.exports = createClass({
   displayName: "AddonsPanel",
 
+  propTypes: {
+    client: PropTypes.instanceOf(DebuggerClient).isRequired,
+    id: PropTypes.string.isRequired
+  },
+
   getInitialState() {
     return {
       extensions: [],
       debugDisabled: false,
     };
   },
 
   componentDidMount() {
@@ -120,16 +128,17 @@ module.exports = createClass({
     },
     PanelHeader({
       id: id + "-header",
       name: Strings.GetStringFromName("addons")
     }),
     AddonsControls({ debugDisabled }),
     dom.div({ id: "addons" },
       TargetList({
+        id: "extensions",
         name,
         targets,
         client,
         debugDisabled,
         targetClass,
         sort: true
       })
     ));

--- a/devtools/client/aboutdebugging/components/addons/target.js
+++ b/devtools/client/aboutdebugging/components/addons/target.js
@@ -1,27 +1,45 @@
 /* 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/. */
 
 /* eslint-env browser */
 
 "use strict";
 
-const { createClass, DOM: dom } =
+const { createClass, DOM: dom, PropTypes } =
   require("devtools/client/shared/vendor/react");
 const { debugAddon } = require("../../modules/addon");
 const Services = require("Services");
 
+loader.lazyImporter(this, "BrowserToolboxProcess",
+  "resource://devtools/client/framework/ToolboxProcess.jsm");
+
+loader.lazyRequireGetter(this, "DebuggerClient",
+  "devtools/shared/client/main", true);
+
 const Strings = Services.strings.createBundle(
   "chrome://devtools/locale/aboutdebugging.properties");
 
 module.exports = createClass({
   displayName: "AddonTarget",
 
+  propTypes: {
+    client: PropTypes.instanceOf(DebuggerClient).isRequired,
+    debugDisabled: PropTypes.bool,
+    target: PropTypes.shape({
+      addonActor: PropTypes.string.isRequired,
+      addonID: PropTypes.string.isRequired,
+      icon: PropTypes.string,
+      name: PropTypes.string.isRequired,
+      temporarilyInstalled: PropTypes.bool
+    }).isRequired
+  },
+
   debug() {
     let { target } = this.props;
     debugAddon(target.addonID);
   },
 
   reload() {
     let { client, target } = this.props;
     // This function sometimes returns a partial promise that only

--- a/devtools/client/aboutdebugging/components/panel-header.js
+++ b/devtools/client/aboutdebugging/components/panel-header.js
@@ -1,19 +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/. */
 
 "use strict";
 
-const { createClass, DOM: dom } =
+const { createClass, DOM: dom, PropTypes } =
   require("devtools/client/shared/vendor/react");
 
 module.exports = createClass({
   displayName: "PanelHeader",
 
+  propTypes: {
+    id: PropTypes.string.isRequired,
+    name: PropTypes.string.isRequired
+  },
+
   render() {
     let { name, id } = this.props;
 
     return dom.div({ className: "header" },
       dom.h1({ id, className: "header-name" }, name));
   },
 });

--- a/devtools/client/aboutdebugging/components/panel-menu-entry.js
+++ b/devtools/client/aboutdebugging/components/panel-menu-entry.js
@@ -1,20 +1,28 @@
 /* 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/. */
 
 "use strict";
 
-const { createClass, DOM: dom } =
+const { createClass, DOM: dom, PropTypes } =
   require("devtools/client/shared/vendor/react");
 
 module.exports = createClass({
   displayName: "PanelMenuEntry",
 
+  propTypes: {
+    icon: PropTypes.string.isRequired,
+    id: PropTypes.string.isRequired,
+    name: PropTypes.string.isRequired,
+    selected: PropTypes.bool,
+    selectPanel: PropTypes.func.isRequired
+  },
+
   onClick() {
     this.props.selectPanel(this.props.id);
   },
 
   onKeyDown(event) {
     if ([" ", "Enter"].includes(event.key)) {
       this.props.selectPanel(this.props.id);
     }

--- a/devtools/client/aboutdebugging/components/panel-menu.js
+++ b/devtools/client/aboutdebugging/components/panel-menu.js
@@ -1,21 +1,32 @@
 /* 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/. */
 
 "use strict";
 
-const { createClass, createFactory, DOM: dom } =
+const { createClass, createFactory, DOM: dom, PropTypes } =
   require("devtools/client/shared/vendor/react");
 const PanelMenuEntry = createFactory(require("./panel-menu-entry"));
 
 module.exports = createClass({
   displayName: "PanelMenu",
 
+  propTypes: {
+    panels: PropTypes.arrayOf(PropTypes.shape({
+      id: PropTypes.string.isRequired,
+      name: PropTypes.string.isRequired,
+      icon: PropTypes.string.isRequired,
+      component: PropTypes.func.isRequired
+    })).isRequired,
+    selectPanel: PropTypes.func.isRequired,
+    selectedPanelId: PropTypes.string
+  },
+
   render() {
     let { panels, selectedPanelId, selectPanel } = this.props;
     let panelLinks = panels.map(({ id, name, icon }) => {
       let selected = id == selectedPanelId;
       return PanelMenuEntry({
         id,
         name,
         icon,

--- a/devtools/client/aboutdebugging/components/tabs/panel.js
+++ b/devtools/client/aboutdebugging/components/tabs/panel.js
@@ -1,30 +1,38 @@
 /* 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/. */
 
 /* eslint-env browser */
 
 "use strict";
 
-const { createClass, createFactory, DOM: dom } =
+const { createClass, createFactory, DOM: dom, PropTypes } =
   require("devtools/client/shared/vendor/react");
 const Services = require("Services");
 
 const PanelHeader = createFactory(require("../panel-header"));
 const TargetList = createFactory(require("../target-list"));
 const TabTarget = createFactory(require("./target"));
 
+loader.lazyRequireGetter(this, "DebuggerClient",
+  "devtools/shared/client/main", true);
+
 const Strings = Services.strings.createBundle(
   "chrome://devtools/locale/aboutdebugging.properties");
 
 module.exports = createClass({
   displayName: "TabsPanel",
 
+  propTypes: {
+    client: PropTypes.instanceOf(DebuggerClient).isRequired,
+    id: PropTypes.string.isRequired
+  },
+
   getInitialState() {
     return {
       tabs: []
     };
   },
 
   componentDidMount() {
     let { client } = this.props;

--- a/devtools/client/aboutdebugging/components/tabs/target.js
+++ b/devtools/client/aboutdebugging/components/tabs/target.js
@@ -1,26 +1,35 @@
 /* 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/. */
 
 /* eslint-env browser */
 
 "use strict";
 
-const { createClass, DOM: dom } =
+const { createClass, DOM: dom, PropTypes } =
   require("devtools/client/shared/vendor/react");
 const Services = require("Services");
 
 const Strings = Services.strings.createBundle(
   "chrome://devtools/locale/aboutdebugging.properties");
 
 module.exports = createClass({
   displayName: "TabTarget",
 
+  propTypes: {
+    target: PropTypes.shape({
+      icon: PropTypes.string,
+      outerWindowID: PropTypes.number.isRequired,
+      title: PropTypes.string,
+      url: PropTypes.string.isRequired
+    }).isRequired
+  },
+
   debug() {
     let { target } = this.props;
     window.open("about:devtools-toolbox?type=tab&id=" + target.outerWindowID);
   },
 
   render() {
     let { target } = this.props;
 

--- a/devtools/client/aboutdebugging/components/target-list.js
+++ b/devtools/client/aboutdebugging/components/target-list.js
@@ -1,28 +1,42 @@
 /* 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/. */
 
 "use strict";
 
-const { createClass, DOM: dom } =
+const { createClass, DOM: dom, PropTypes } =
   require("devtools/client/shared/vendor/react");
 const Services = require("Services");
 
+loader.lazyRequireGetter(this, "DebuggerClient",
+  "devtools/shared/client/main", true);
+
 const Strings = Services.strings.createBundle(
   "chrome://devtools/locale/aboutdebugging.properties");
 
 const LocaleCompare = (a, b) => {
   return a.name.toLowerCase().localeCompare(b.name.toLowerCase());
 };
 
 module.exports = createClass({
   displayName: "TargetList",
 
+  propTypes: {
+    client: PropTypes.instanceOf(DebuggerClient).isRequired,
+    debugDisabled: PropTypes.bool,
+    error: PropTypes.node,
+    id: PropTypes.string.isRequired,
+    name: PropTypes.string,
+    sort: PropTypes.bool,
+    targetClass: PropTypes.func.isRequired,
+    targets: PropTypes.arrayOf(PropTypes.object).isRequired
+  },
+
   render() {
     let { client, debugDisabled, error, targetClass, targets, sort } = this.props;
     if (sort) {
       targets = targets.sort(LocaleCompare);
     }
     targets = targets.map(target => {
       return targetClass({ client, target, debugDisabled });
     });

--- a/devtools/client/aboutdebugging/components/workers/panel.js
+++ b/devtools/client/aboutdebugging/components/workers/panel.js
@@ -3,35 +3,46 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 /* globals window */
 "use strict";
 
 loader.lazyImporter(this, "PrivateBrowsingUtils",
   "resource://gre/modules/PrivateBrowsingUtils.jsm");
 
 const { Ci } = require("chrome");
-const { createClass, createFactory, DOM: dom } =
+const { createClass, createFactory, DOM: dom, PropTypes } =
   require("devtools/client/shared/vendor/react");
 const { getWorkerForms } = require("../../modules/worker");
 const Services = require("Services");
 
 const PanelHeader = createFactory(require("../panel-header"));
 const TargetList = createFactory(require("../target-list"));
 const WorkerTarget = createFactory(require("./target"));
 const ServiceWorkerTarget = createFactory(require("./service-worker-target"));
 
+loader.lazyImporter(this, "PrivateBrowsingUtils",
+  "resource://gre/modules/PrivateBrowsingUtils.jsm");
+
+loader.lazyRequireGetter(this, "DebuggerClient",
+  "devtools/shared/client/main", true);
+
 const Strings = Services.strings.createBundle(
   "chrome://devtools/locale/aboutdebugging.properties");
 
 const WorkerIcon = "chrome://devtools/skin/images/debugging-workers.svg";
 const MORE_INFO_URL = "https://developer.mozilla.org/en-US/docs/Tools/about%3Adebugging";
 
 module.exports = createClass({
   displayName: "WorkersPanel",
 
+  propTypes: {
+    client: PropTypes.instanceOf(DebuggerClient).isRequired,
+    id: PropTypes.string.isRequired
+  },
+
   getInitialState() {
     return {
       workers: {
         service: [],
         shared: [],
         other: []
       }
     };

--- a/devtools/client/aboutdebugging/components/workers/service-worker-target.js
+++ b/devtools/client/aboutdebugging/components/workers/service-worker-target.js
@@ -1,27 +1,45 @@
 /* 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/. */
 
 /* eslint-env browser */
 
 "use strict";
 
-const { createClass, DOM: dom } =
+const { createClass, DOM: dom, PropTypes } =
   require("devtools/client/shared/vendor/react");
 const { debugWorker } = require("../../modules/worker");
 const Services = require("Services");
 
+loader.lazyRequireGetter(this, "DebuggerClient",
+  "devtools/shared/client/main", true);
+
 const Strings = Services.strings.createBundle(
   "chrome://devtools/locale/aboutdebugging.properties");
 
 module.exports = createClass({
   displayName: "ServiceWorkerTarget",
 
+  propTypes: {
+    client: PropTypes.instanceOf(DebuggerClient).isRequired,
+    debugDisabled: PropTypes.bool,
+    target: PropTypes.shape({
+      active: PropTypes.bool,
+      icon: PropTypes.string,
+      name: PropTypes.string.isRequired,
+      url: PropTypes.string,
+      scope: PropTypes.string.isRequired,
+      // registrationActor can be missing in e10s.
+      registrationActor: PropTypes.string,
+      workerActor: PropTypes.string
+    }).isRequired
+  },
+
   getInitialState() {
     return {
       pushSubscription: null
     };
   },
 
   componentDidMount() {
     let { client } = this.props;

--- a/devtools/client/aboutdebugging/components/workers/target.js
+++ b/devtools/client/aboutdebugging/components/workers/target.js
@@ -1,27 +1,40 @@
 /* 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/. */
 
 /* eslint-env browser */
 
 "use strict";
 
-const { createClass, DOM: dom } =
+const { createClass, DOM: dom, PropTypes } =
   require("devtools/client/shared/vendor/react");
 const { debugWorker } = require("../../modules/worker");
 const Services = require("Services");
 
+loader.lazyRequireGetter(this, "DebuggerClient",
+  "devtools/shared/client/main", true);
+
 const Strings = Services.strings.createBundle(
   "chrome://devtools/locale/aboutdebugging.properties");
 
 module.exports = createClass({
   displayName: "WorkerTarget",
 
+  propTypes: {
+    client: PropTypes.instanceOf(DebuggerClient).isRequired,
+    debugDisabled: PropTypes.bool,
+    target: PropTypes.shape({
+      icon: PropTypes.string,
+      name: PropTypes.string.isRequired,
+      workerActor: PropTypes.string
+    }).isRequired
+  },
+
   debug() {
     let { client, target } = this.props;
     debugWorker(client, target.workerActor);
   },
 
   render() {
     let { target, debugDisabled } = this.props;
 

--- a/devtools/client/responsive.html/test/browser/browser.ini
+++ b/devtools/client/responsive.html/test/browser/browser.ini
@@ -33,12 +33,11 @@ support-files =
 [browser_permission_doorhanger.js]
 [browser_resize_cmd.js]
 [browser_screenshot_button.js]
 [browser_tab_close.js]
 [browser_tab_remoteness_change.js]
 [browser_toolbox_computed_view.js]
 [browser_toolbox_rule_view.js]
 [browser_toolbox_swap_browsers.js]
-skip-if = true # Bug 1315042
 [browser_touch_simulation.js]
 [browser_viewport_basics.js]
 [browser_window_close.js]

--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@@ -3568,31 +3568,73 @@ nsDocShell::CanAccessItem(nsIDocShellTre
   }
 
   if (targetDS->GetIsInIsolatedMozBrowserElement() !=
         accessingDS->GetIsInIsolatedMozBrowserElement() ||
       targetDS->GetAppId() != accessingDS->GetAppId()) {
     return false;
   }
 
-  if (static_cast<nsDocShell*>(targetDS.get())->GetOriginAttributes() !=
-      static_cast<nsDocShell*>(accessingDS.get())->GetOriginAttributes()) {
+  nsCOMPtr<nsIDocShellTreeItem> accessingRoot;
+  aAccessingItem->GetSameTypeRootTreeItem(getter_AddRefs(accessingRoot));
+  nsCOMPtr<nsIDocShell> accessingRootDS = do_QueryInterface(accessingRoot);
+
+  nsCOMPtr<nsIDocShellTreeItem> targetRoot;
+  aTargetItem->GetSameTypeRootTreeItem(getter_AddRefs(targetRoot));
+  nsCOMPtr<nsIDocShell> targetRootDS = do_QueryInterface(targetRoot);
+
+  DocShellOriginAttributes targetOA =
+    static_cast<nsDocShell*>(targetDS.get())->GetOriginAttributes();
+  DocShellOriginAttributes accessingOA =
+    static_cast<nsDocShell*>(accessingDS.get())->GetOriginAttributes();
+
+  // When the first party isolation is on, the top-level docShell may not have
+  // the firstPartyDomain in its originAttributes, but its document will have
+  // it. So we get the firstPartyDomain from the nodePrincipal of the document
+  // before we compare the originAttributes.
+  if (OriginAttributes::IsFirstPartyEnabled()) {
+    if (accessingDS == accessingRootDS &&
+        aAccessingItem->ItemType() == nsIDocShellTreeItem::typeContent &&
+        !accessingDS->GetIsMozBrowserOrApp()) {
+
+      nsCOMPtr<nsIDocument> accessingDoc = aAccessingItem->GetDocument();
+
+      if (accessingDoc) {
+        nsCOMPtr<nsIPrincipal> accessingPrincipal = accessingDoc->NodePrincipal();
+
+        accessingOA.mFirstPartyDomain =
+          BasePrincipal::Cast(accessingPrincipal)->OriginAttributesRef().mFirstPartyDomain;
+      }
+    }
+
+    if (targetDS == targetRootDS &&
+        aTargetItem->ItemType() == nsIDocShellTreeItem::typeContent &&
+        !targetDS->GetIsMozBrowserOrApp()) {
+
+      nsCOMPtr<nsIDocument> targetDoc = aAccessingItem->GetDocument();
+
+      if (targetDoc) {
+        nsCOMPtr<nsIPrincipal> targetPrincipal = targetDoc->NodePrincipal();
+
+        targetOA.mFirstPartyDomain =
+          BasePrincipal::Cast(targetPrincipal)->OriginAttributesRef().mFirstPartyDomain;
+      }
+    }
+  }
+
+  if (targetOA != accessingOA) {
     return false;
   }
 
   // A private document can't access a non-private one, and vice versa.
   if (static_cast<nsDocShell*>(targetDS.get())->UsePrivateBrowsing() !=
       static_cast<nsDocShell*>(accessingDS.get())->UsePrivateBrowsing()) {
     return false;
   }
 
-
-  nsCOMPtr<nsIDocShellTreeItem> accessingRoot;
-  aAccessingItem->GetSameTypeRootTreeItem(getter_AddRefs(accessingRoot));
-
   if (aTargetItem == accessingRoot) {
     // A frame can navigate its root.
     return true;
   }
 
   // Check if aAccessingItem can navigate one of aTargetItem's ancestors.
   nsCOMPtr<nsIDocShellTreeItem> target = aTargetItem;
   do {
@@ -3600,19 +3642,16 @@ nsDocShell::CanAccessItem(nsIDocShellTre
       return true;
     }
 
     nsCOMPtr<nsIDocShellTreeItem> parent;
     target->GetSameTypeParent(getter_AddRefs(parent));
     parent.swap(target);
   } while (target);
 
-  nsCOMPtr<nsIDocShellTreeItem> targetRoot;
-  aTargetItem->GetSameTypeRootTreeItem(getter_AddRefs(targetRoot));
-
   if (aTargetItem != targetRoot) {
     // target is a subframe, not in accessor's frame hierarchy, and all its
     // ancestors have origins different from that of the accessor. Don't
     // allow access.
     return false;
   }
 
   if (!aConsiderOpener) {

--- a/dom/base/test/browser.ini
+++ b/dom/base/test/browser.ini
@@ -15,17 +15,16 @@ support-files =
   file_use_counter_svg_fill_pattern_data.svg
 
 [browser_bug593387.js]
 [browser_bug902350.js]
 tags = mcb
 [browser_bug1011748.js]
 [browser_bug1058164.js]
 [browser_messagemanager_loadprocessscript.js]
-skip-if = e10s # Bug 1315042
 [browser_messagemanager_targetframeloader.js]
 [browser_messagemanager_unload.js]
 [browser_pagehide_on_tab_close.js]
 skip-if = e10s # this tests non-e10s behavior. it's not expected to work in e10s.
 [browser_state_notifications.js]
 skip-if = true # Bug 1271028
 [browser_use_counters.js]
 [browser_bug1307747.js]

--- a/dom/browser-element/mochitest/mochitest-oop.ini
+++ b/dom/browser-element/mochitest/mochitest-oop.ini
@@ -66,17 +66,16 @@ disabled = disabled for bug 1266035
 [test_browserElement_oop_OpenWindow.html]
 [test_browserElement_oop_OpenWindowDifferentOrigin.html]
 [test_browserElement_oop_OpenWindowInFrame.html]
 [test_browserElement_oop_OpenWindowRejected.html]
 [test_browserElement_oop_Opensearch.html]
 [test_browserElement_oop_OpenTab.html]
 disabled = Disabling some OOP tests for WebIDL scope changes
 [test_browserElement_oop_PrivateBrowsing.html]
-skip-if = e10s # Bug 1315042
 [test_browserElement_oop_PromptCheck.html]
 [test_browserElement_oop_PromptConfirm.html]
 [test_browserElement_oop_Proxy.html]
 [test_browserElement_oop_PurgeHistory.html]
 disabled = Disabling some OOP tests for WebIDL scope changes
 [test_browserElement_oop_Reload.html]
 disabled = Disabling some OOP tests for WebIDL scope changes
 [test_browserElement_oop_ReloadPostRequest.html]

--- a/dom/canvas/WebGLFormats.cpp
+++ b/dom/canvas/WebGLFormats.cpp
@@ -163,17 +163,17 @@ AddFormatInfo(EffectiveFormat format, co
     case UnsizedFormat::D:
         MOZ_ASSERT(!r && !g && !b && !a && d && !s);
         break;
 
     case UnsizedFormat::S:
         MOZ_ASSERT(!r && !g && !b && !a && !d && s);
         break;
 
-    case UnsizedFormat::DS:
+    case UnsizedFormat::DEPTH_STENCIL:
         MOZ_ASSERT(!r && !g && !b && !a && d && s);
         break;
     }
 
     const CompressedFormatInfo* compressedFormatInfo = GetCompressedFormatInfo(format);
     MOZ_ASSERT(!bytesPerPixel == bool(compressedFormatInfo));
 
 #ifdef DEBUG
@@ -257,18 +257,18 @@ InitFormatInfo()
     AddFormatInfo(FOO(RGBA16UI      ),  8, 16,16,16,16,  0,0, UnsizedFormat::RGBA, false, ComponentType::UInt    );
     AddFormatInfo(FOO(RGBA32I       ), 16, 32,32,32,32,  0,0, UnsizedFormat::RGBA, false, ComponentType::Int     );
     AddFormatInfo(FOO(RGBA32UI      ), 16, 32,32,32,32,  0,0, UnsizedFormat::RGBA, false, ComponentType::UInt    );
 
     // GLES 3.0.4, p133, table 3.14
     AddFormatInfo(FOO(DEPTH_COMPONENT16 ), 2, 0,0,0,0, 16,0, UnsizedFormat::D , false, ComponentType::NormUInt);
     AddFormatInfo(FOO(DEPTH_COMPONENT24 ), 3, 0,0,0,0, 24,0, UnsizedFormat::D , false, ComponentType::NormUInt);
     AddFormatInfo(FOO(DEPTH_COMPONENT32F), 4, 0,0,0,0, 32,0, UnsizedFormat::D , false, ComponentType::Float);
-    AddFormatInfo(FOO(DEPTH24_STENCIL8  ), 4, 0,0,0,0, 24,8, UnsizedFormat::DS, false, ComponentType::Special);
-    AddFormatInfo(FOO(DEPTH32F_STENCIL8 ), 5, 0,0,0,0, 32,8, UnsizedFormat::DS, false, ComponentType::Special);
+    AddFormatInfo(FOO(DEPTH24_STENCIL8  ), 4, 0,0,0,0, 24,8, UnsizedFormat::DEPTH_STENCIL, false, ComponentType::Special);
+    AddFormatInfo(FOO(DEPTH32F_STENCIL8 ), 5, 0,0,0,0, 32,8, UnsizedFormat::DEPTH_STENCIL, false, ComponentType::Special);
 
     // GLES 3.0.4, p205-206, "Required Renderbuffer Formats"
     AddFormatInfo(FOO(STENCIL_INDEX8), 1, 0,0,0,0, 0,8, UnsizedFormat::S, false, ComponentType::UInt);
 
     // GLES 3.0.4, p147, table 3.19
     // GLES 3.0.4  p286+  $C.1 "ETC Compressed Texture Image Formats"
     AddFormatInfo(FOO(COMPRESSED_RGB8_ETC2                     ), 0, 1,1,1,0, 0,0, UnsizedFormat::RGB , false, ComponentType::NormUInt);
     AddFormatInfo(FOO(COMPRESSED_SRGB8_ETC2                    ), 0, 1,1,1,0, 0,0, UnsizedFormat::RGB , true , ComponentType::NormUInt);

--- a/dom/canvas/WebGLFormats.h
+++ b/dom/canvas/WebGLFormats.h
@@ -153,17 +153,17 @@ enum class UnsizedFormat : uint8_t {
     RG,
     RGB,
     RGBA,
     LA,
     L,
     A,
     D,
     S,
-    DS,
+    DEPTH_STENCIL, // `DS` is a macro on Solaris. (regset.h)
 };
 
 // GLES 3.0.4 p114 Table 3.4, p240
 enum class ComponentType : uint8_t {
     None,
     Int,          // RGBA32I
     UInt,         // RGBA32UI, STENCIL_INDEX8
     NormInt,      // RGBA8_SNORM

--- a/dom/canvas/WebGLFramebuffer.cpp
+++ b/dom/canvas/WebGLFramebuffer.cpp
@@ -532,17 +532,17 @@ WebGLFBAttachPoint::GetParameter(const c
                               : LOCAL_GL_LINEAR);
         break;
 
     case LOCAL_GL_FRAMEBUFFER_ATTACHMENT_COMPONENT_TYPE:
         MOZ_ASSERT(attachment != LOCAL_GL_DEPTH_STENCIL_ATTACHMENT);
 
         if (format->componentType == webgl::ComponentType::Special) {
             // Special format is used for DS mixed format(e.g. D24S8 and D32FS8).
-            MOZ_ASSERT(format->unsizedFormat == webgl::UnsizedFormat::DS);
+            MOZ_ASSERT(format->unsizedFormat == webgl::UnsizedFormat::DEPTH_STENCIL);
             MOZ_ASSERT(attachment == LOCAL_GL_DEPTH_ATTACHMENT ||
                        attachment == LOCAL_GL_STENCIL_ATTACHMENT);
 
             if (attachment == LOCAL_GL_DEPTH_ATTACHMENT) {
                 switch (format->effectiveFormat) {
                 case webgl::EffectiveFormat::DEPTH24_STENCIL8:
                     format = webgl::GetFormat(webgl::EffectiveFormat::DEPTH_COMPONENT24);
                     break;

--- a/dom/ipc/Blob.cpp
+++ b/dom/ipc/Blob.cpp
@@ -204,17 +204,21 @@ ActorManagerIsSameProcess(PBackgroundPar
 bool
 EventTargetIsOnCurrentThread(nsIEventTarget* aEventTarget)
 {
   if (!aEventTarget) {
     return NS_IsMainThread();
   }
 
   bool current;
-  MOZ_ALWAYS_SUCCEEDS(aEventTarget->IsOnCurrentThread(&current));
+
+  // If this fails, we are probably shutting down.
+  if (NS_WARN_IF(NS_FAILED(aEventTarget->IsOnCurrentThread(&current)))) {
+    return true;
+  }
 
   return current;
 }
 
 class CancelableRunnableWrapper final
   : public CancelableRunnable
 {
   nsCOMPtr<nsIRunnable> mRunnable;

--- a/dom/media/platforms/omx/moz.build
+++ b/dom/media/platforms/omx/moz.build
@@ -43,8 +43,15 @@ if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'gonk
     EXTRA_DSO_LDOPTS += [
         '-libbinder',
     ]
 
 FINAL_LIBRARY = 'xul'
 
 if CONFIG['GNU_CXX']:
     CXXFLAGS += ['-Wno-error=shadow']
+
+if CONFIG['_MSC_VER']:
+    # Avoid warnings from third-party code that we can not modify.
+    if CONFIG['CLANG_CL']:
+        CXXFLAGS += ['-Wno-invalid-source-encoding']
+    else:
+        CXXFLAGS += ['-validate-charset-']

--- a/embedding/components/printingui/ipc/PrintDataUtils.cpp
+++ b/embedding/components/printingui/ipc/PrintDataUtils.cpp
@@ -1,16 +1,15 @@
 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
 /* vim: set sw=4 ts=8 et 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 "PrintDataUtils.h"
-#include "nsIPrintOptions.h"
 #include "nsIPrintSettings.h"
 #include "nsIServiceManager.h"
 #include "nsIWebBrowserPrint.h"
 #include "nsXPIDLString.h"
 
 namespace mozilla {
 namespace embedding {
 

--- a/embedding/components/printingui/win/nsPrintDialogUtil.cpp
+++ b/embedding/components/printingui/win/nsPrintDialogUtil.cpp
@@ -28,17 +28,17 @@ WIN_LIBS=                               
 #include <commdlg.h>
 
 #include "nsIWebBrowserPrint.h"
 #include "nsString.h"
 #include "nsIServiceManager.h"
 #include "nsReadableUtils.h"
 #include "nsIPrintSettings.h"
 #include "nsIPrintSettingsWin.h"
-#include "nsIPrintOptions.h"
+#include "nsIPrinterEnumerator.h"
 
 #include "nsRect.h"
 
 #include "nsIPrefService.h"
 #include "nsIPrefBranch.h"
 
 #include "nsCRT.h"
 #include "prenv.h" /* for PR_GetEnv */

--- a/extensions/spellcheck/hunspell/glue/mozHunspell.cpp
+++ b/extensions/spellcheck/hunspell/glue/mozHunspell.cpp
@@ -7,24 +7,24 @@
  * http://www.mozilla.org/MPL/
  *
  * Software distributed under the License is distributed on an "AS IS" basis,
  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  * for the specific language governing rights and limitations under the
  * License.
  *
  * The Initial Developers of the Original Code are Kevin Hendricks (MySpell)
- * and L�szl� N�meth (Hunspell). Portions created by the Initial Developers
+ * and László Németh (Hunspell). Portions created by the Initial Developers
  * are Copyright (C) 2002-2005 the Initial Developers. All Rights Reserved.
  *
  * Contributor(s): Kevin Hendricks (kevin.hendricks@sympatico.ca)
  *                 David Einstein (deinst@world.std.com)
  *                 Michiel van Leeuwen (mvl@exedo.nl)
  *                 Caolan McNamara (cmc@openoffice.org)
- *                 L�szl� N�meth (nemethl@gyorsposta.hu)
+ *                 László Németh (nemethl@gyorsposta.hu)
  *                 Davide Prina
  *                 Giuseppe Modugno
  *                 Gianluca Turconi
  *                 Simon Brouwer
  *                 Noll Janos
  *                 Biro Arpad
  *                 Goldman Eleonora
  *                 Sarlos Tamas

--- a/extensions/spellcheck/hunspell/glue/mozHunspell.h
+++ b/extensions/spellcheck/hunspell/glue/mozHunspell.h
@@ -7,24 +7,24 @@
  * http://www.mozilla.org/MPL/
  * 
  * Software distributed under the License is distributed on an "AS IS" basis,
  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  * for the specific language governing rights and limitations under the
  * License.
  * 
  * The Initial Developers of the Original Code are Kevin Hendricks (MySpell)
- * and L�szl� N�meth (Hunspell). Portions created by the Initial Developers
+ * and László Németh (Hunspell). Portions created by the Initial Developers
  * are Copyright (C) 2002-2005 the Initial Developers. All Rights Reserved.
  * 
  * Contributor(s): Kevin Hendricks (kevin.hendricks@sympatico.ca)
  *                 David Einstein (deinst@world.std.com)
  *                 Michiel van Leeuwen (mvl@exedo.nl)
  *                 Caolan McNamara (cmc@openoffice.org)
- *                 L�szl� N�meth (nemethl@gyorsposta.hu)
+ *                 László Németh (nemethl@gyorsposta.hu)
  *                 Davide Prina
  *                 Giuseppe Modugno
  *                 Gianluca Turconi
  *                 Simon Brouwer
  *                 Noll Janos
  *                 Biro Arpad
  *                 Goldman Eleonora
  *                 Sarlos Tamas

--- a/extensions/spellcheck/hunspell/glue/mozHunspellDirProvider.cpp
+++ b/extensions/spellcheck/hunspell/glue/mozHunspellDirProvider.cpp
@@ -7,21 +7,21 @@
  * http://www.mozilla.org/MPL/
  * 
  * Software distributed under the License is distributed on an "AS IS" basis,
  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  * for the specific language governing rights and limitations under the
  * License.
  * 
  * The Initial Developers of the Original Code are Kevin Hendricks (MySpell)
- * and L�szl� N�meth (Hunspell). Portions created by the Initial Developers
+ * and László Németh (Hunspell). Portions created by the Initial Developers
  * are Copyright (C) 2002-2005 the Initial Developers. All Rights Reserved.
  * 
  * Contributor(s): Benjamin Smedberg (benjamin@smedbergs.us) (Original Code)
- *                 L�szl� N�meth (nemethl@gyorsposta.hu)
+ *                 László Németh (nemethl@gyorsposta.hu)
  *                 Ryan VanderMeulen (ryanvm@gmail.com)
  * 
  * Alternatively, the contents of this file may be used under the terms of
  * either the GNU General Public License Version 2 or later (the "GPL"), or
  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  * in which case the provisions of the GPL or the LGPL are applicable instead
  * of those above. If you wish to allow use of your version of this file only
  * under the terms of either the GPL or the LGPL, and not to allow others to

--- a/extensions/spellcheck/hunspell/glue/mozHunspellDirProvider.h
+++ b/extensions/spellcheck/hunspell/glue/mozHunspellDirProvider.h
@@ -7,21 +7,21 @@
  * http://www.mozilla.org/MPL/
  * 
  * Software distributed under the License is distributed on an "AS IS" basis,
  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  * for the specific language governing rights and limitations under the
  * License.
  * 
  * The Initial Developers of the Original Code are Kevin Hendricks (MySpell)
- * and L�szl� N�meth (Hunspell). Portions created by the Initial Developers
+ * and László Németh (Hunspell). Portions created by the Initial Developers
  * are Copyright (C) 2002-2005 the Initial Developers. All Rights Reserved.
  * 
  * Contributor(s): Benjamin Smedberg (benjamin@smedbergs.us) (Original Code)
- *                 L�szl� N�meth (nemethl@gyorsposta.hu)
+ *                 László Németh (nemethl@gyorsposta.hu)
  *                 Ryan VanderMeulen (ryanvm@gmail.com)
  * 
  * Alternatively, the contents of this file may be used under the terms of
  * either the GNU General Public License Version 2 or later (the "GPL"), or
  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  * in which case the provisions of the GPL or the LGPL are applicable instead
  * of those above. If you wish to allow use of your version of this file only
  * under the terms of either the GPL or the LGPL, and not to allow others to

--- a/gfx/2d/DrawTargetSkia.cpp
+++ b/gfx/2d/DrawTargetSkia.cpp
@@ -1562,20 +1562,27 @@ DrawTargetSkia::CreateSimilarDrawTarget(
     // Try to create a GPU draw target first if we're currently using the GPU.
     // Mark the DT as cached so that shadow DTs, extracted subrects, and similar can be reused.
     if (target->InitWithGrContext(mGrContext.get(), aSize, aFormat, true)) {
       return target.forget();
     }
     // Otherwise, just fall back to a software draw target.
   }
 #endif
+
+#ifdef DEBUG
   // Check that our SkCanvas isn't backed by vector storage such as PDF.  If it
-  // is then we want similar storage to avoid losing fidelity.
-  MOZ_ASSERT(mCanvas->imageInfo().colorType() != kUnknown_SkColorType,
-             "Not backed by pixels - we need to handle PDF backed SkCanvas");
+  // is then we want similar storage to avoid losing fidelity (if and when this
+  // DrawTarget is Snapshot()'ed, drawning a raster back into this DrawTarget
+  // will lose fidelity).
+  if (mCanvas->imageInfo().colorType() != kUnknown_SkColorType) {
+    NS_WARNING("Not backed by pixels - we need to handle PDF backed SkCanvas");
+  }
+#endif
+
   if (!target->Init(aSize, aFormat)) {
     return nullptr;
   }
   return target.forget();
 }
 
 bool
 DrawTargetSkia::UsingSkiaGPU() const

--- a/gfx/2d/Factory.cpp
+++ b/gfx/2d/Factory.cpp
@@ -506,16 +506,19 @@ Factory::CreateNativeFontResource(uint8_
 #ifdef WIN32
   case FontType::DWRITE:
     {
       return NativeFontResourceDWrite::Create(aData, aSize,
                                               /* aNeedsCairo = */ false);
     }
 #endif
   case FontType::CAIRO:
+#ifdef USE_SKIA
+  case FontType::SKIA:
+#endif
     {
 #ifdef WIN32
       if (GetDirect3D11Device()) {
         return NativeFontResourceDWrite::Create(aData, aSize,
                                                 /* aNeedsCairo = */ true);
       } else {
         return NativeFontResourceGDI::Create(aData, aSize,
                                              /* aNeedsCairo = */ true);

--- a/gfx/cairo/cairo/src/cairo-platform.h
+++ b/gfx/cairo/cairo/src/cairo-platform.h
@@ -1,11 +1,11 @@
 /* cairo - a vector graphics library with display and print output
  *
- * Copyright �� 2005 Mozilla Foundation
+ * Copyright © 2005 Mozilla Foundation
  *
  * This library is free software; you can redistribute it and/or
  * modify it either under the terms of the GNU Lesser General Public
  * License version 2.1 as published by the Free Software Foundation
  * (the "LGPL") or, at your option, under the terms of the Mozilla
  * Public License Version 1.1 (the "MPL"). If you do not alter this
  * notice, a recipient may use your version of this file under either
  * the MPL or the LGPL.

--- a/gfx/layers/client/TextureClient.cpp
+++ b/gfx/layers/client/TextureClient.cpp
@@ -89,17 +89,17 @@ void DeallocateTextureClient(TextureDeal
  * deallocte or recycle the it.
  */
 class TextureChild final : PTextureChild
 {
   ~TextureChild()
   {
     // We should have deallocated mTextureData in ActorDestroy
     MOZ_ASSERT(!mTextureData);
-    MOZ_ASSERT(mOwnerCalledDestroy);
+    MOZ_ASSERT_IF(!mOwnerCalledDestroy, !mTextureClient);
   }
 public:
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(TextureChild)
 
   TextureChild()
   : mCompositableForwarder(nullptr)
   , mTextureForwarder(nullptr)
   , mTextureClient(nullptr)
@@ -930,21 +930,30 @@ TextureClient::InitIPDLActor(KnowsCompos
   }
   MOZ_ASSERT(!mActor || mActor->mDestroyed, "Cannot use a texture on several IPC channels.");
 
   SurfaceDescriptor desc;
   if (!ToSurfaceDescriptor(desc)) {
     return false;
   }
 
-  mActor = static_cast<TextureChild*>(fwd->CreateTexture(desc,
-                                      aForwarder->GetCompositorBackendType(),
-                                      GetFlags(),
-                                      mSerial));
-  MOZ_ASSERT(mActor);
+  PTextureChild* actor = fwd->CreateTexture(
+    desc,
+    aForwarder->GetCompositorBackendType(),
+    GetFlags(),
+    mSerial);
+  if (!actor) {
+    gfxCriticalNote << static_cast<int32_t>(desc.type()) << ", "
+                    << static_cast<int32_t>(aForwarder->GetCompositorBackendType()) << ", "
+                    << static_cast<uint32_t>(GetFlags())
+                    << ", " << mSerial;
+    return false;
+  }
+
+  mActor = static_cast<TextureChild*>(actor);
   mActor->mTextureForwarder = fwd;
   mActor->mTextureClient = this;
   mActor->mMainThreadOnly = !!(mFlags & TextureFlags::DEALLOCATE_MAIN_THREAD);
 
   // If the TextureClient is already locked, we have to lock TextureChild's mutex
   // since it will be unlocked in TextureClient::Unlock.
   if (mIsLocked) {
     LockActor();

--- a/gfx/layers/ipc/ShadowLayers.cpp
+++ b/gfx/layers/ipc/ShadowLayers.cpp
@@ -368,42 +368,52 @@ ShadowLayerForwarder::CheckSurfaceDescri
   }
 }
 #endif
 
 void
 ShadowLayerForwarder::UseTiledLayerBuffer(CompositableClient* aCompositable,
                                           const SurfaceDescriptorTiles& aTileLayerDescriptor)
 {
-  MOZ_ASSERT(aCompositable && aCompositable->IsConnected());
+  MOZ_ASSERT(aCompositable);
+
+  if (!aCompositable->IsConnected()) {
+    return;
+  }
 
   mTxn->AddNoSwapPaint(CompositableOperation(nullptr, aCompositable->GetIPDLActor(),
                                              OpUseTiledLayerBuffer(aTileLayerDescriptor)));
 }
 
 void
 ShadowLayerForwarder::UpdateTextureRegion(CompositableClient* aCompositable,
                                           const ThebesBufferData& aThebesBufferData,
                                           const nsIntRegion& aUpdatedRegion)
 {
   MOZ_ASSERT(aCompositable);
-  MOZ_ASSERT(aCompositable);
-  MOZ_ASSERT(aCompositable->IsConnected());
+
+  if (!aCompositable->IsConnected()) {
+    return;
+  }
 
   mTxn->AddPaint(
     CompositableOperation(
       nullptr, aCompositable->GetIPDLActor(),
       OpPaintTextureRegion(aThebesBufferData, aUpdatedRegion)));
 }
 
 void
 ShadowLayerForwarder::UseTextures(CompositableClient* aCompositable,
                                   const nsTArray<TimedTextureClient>& aTextures)
 {
-  MOZ_ASSERT(aCompositable && aCompositable->IsConnected());
+  MOZ_ASSERT(aCompositable);
+
+  if (!aCompositable->IsConnected()) {
+    return;
+  }
 
   AutoTArray<TimedTexture,4> textures;
 
   for (auto& t : aTextures) {
     MOZ_ASSERT(t.mTextureClient);
     MOZ_ASSERT(t.mTextureClient->GetIPDLActor());
     MOZ_RELEASE_ASSERT(t.mTextureClient->GetIPDLActor()->GetIPCChannel() == mShadowManager->GetIPCChannel());
     ReadLockDescriptor readLock;
@@ -427,17 +437,21 @@ ShadowLayerForwarder::UseTextures(Compos
 }
 
 void
 ShadowLayerForwarder::UseComponentAlphaTextures(CompositableClient* aCompositable,
                                                 TextureClient* aTextureOnBlack,
                                                 TextureClient* aTextureOnWhite)
 {
   MOZ_ASSERT(aCompositable);
-  MOZ_ASSERT(aCompositable->IsConnected());
+
+  if (!aCompositable->IsConnected()) {
+    return;
+  }
+
   MOZ_ASSERT(aTextureOnWhite);
   MOZ_ASSERT(aTextureOnBlack);
   MOZ_ASSERT(aCompositable->GetIPDLActor());
   MOZ_ASSERT(aTextureOnBlack->GetIPDLActor());
   MOZ_ASSERT(aTextureOnWhite->GetIPDLActor());
   MOZ_ASSERT(aTextureOnBlack->GetSize() == aTextureOnWhite->GetSize());
   MOZ_RELEASE_ASSERT(aTextureOnWhite->GetIPDLActor()->GetIPCChannel() == mShadowManager->GetIPCChannel());
   MOZ_RELEASE_ASSERT(aTextureOnBlack->GetIPDLActor()->GetIPCChannel() == mShadowManager->GetIPCChannel());
@@ -489,17 +503,16 @@ ShadowLayerForwarder::DestroyInTransacti
 }
 
 void
 ShadowLayerForwarder::RemoveTextureFromCompositable(CompositableClient* aCompositable,
                                                     TextureClient* aTexture)
 {
   MOZ_ASSERT(aCompositable);
   MOZ_ASSERT(aTexture);
-  MOZ_ASSERT(aCompositable->IsConnected());
   MOZ_ASSERT(aTexture->GetIPDLActor());
   MOZ_RELEASE_ASSERT(aTexture->GetIPDLActor()->GetIPCChannel() == mShadowManager->GetIPCChannel());
   if (!aCompositable->IsConnected() || !aTexture->GetIPDLActor()) {
     // We don't have an actor anymore, don't try to use it!
     return;
   }
 
   mTxn->AddEdit(

--- a/gfx/thebes/PrintTargetThebes.cpp
+++ b/gfx/thebes/PrintTargetThebes.cpp
@@ -81,28 +81,37 @@ nsresult
 PrintTargetThebes::EndPrinting()
 {
   return mGfxSurface->EndPrinting();
 }
 
 nsresult
 PrintTargetThebes::AbortPrinting()
 {
+#ifdef DEBUG
+  mHasActivePage = false;
+#endif
   return mGfxSurface->AbortPrinting();
 }
 
 nsresult
 PrintTargetThebes::BeginPage()
 {
+#ifdef DEBUG
+  mHasActivePage = true;
+#endif
   return mGfxSurface->BeginPage();
 }
 
 nsresult
 PrintTargetThebes::EndPage()
 {
+#ifdef DEBUG
+  mHasActivePage = false;
+#endif
   return mGfxSurface->EndPage();
 }
 
 void
 PrintTargetThebes::Finish()
 {
   return mGfxSurface->Finish();
 }

--- a/gfx/thebes/gfxPlatform.cpp
+++ b/gfx/thebes/gfxPlatform.cpp
@@ -972,17 +972,17 @@ gfxPlatform::~gfxPlatform()
 #endif
 
 #if MOZ_TREE_CAIRO
     cairo_debug_reset_static_data();
 #endif
 #endif
 }
 
-already_AddRefed<DrawTarget>
+/* static */ already_AddRefed<DrawTarget>
 gfxPlatform::CreateDrawTargetForSurface(gfxASurface *aSurface, const IntSize& aSize)
 {
   SurfaceFormat format = aSurface->GetSurfaceFormat();
   RefPtr<DrawTarget> drawTarget = Factory::CreateDrawTargetForCairoSurface(aSurface->CairoSurface(), aSize, &format);
   if (!drawTarget) {
     gfxWarning() << "gfxPlatform::CreateDrawTargetForSurface failed in CreateDrawTargetForCairoSurface";
     return nullptr;
   }

--- a/gfx/thebes/gfxPlatform.h
+++ b/gfx/thebes/gfxPlatform.h
@@ -191,17 +191,17 @@ public:
     /**
      * Beware that this method may return DrawTargets which are not fully supported
      * on the current platform and might fail silently in subtle ways. This is a massive
      * potential footgun. You should only use these methods for canvas drawing really.
      * Use extreme caution if you use them for content where you are not 100% sure we
      * support the DrawTarget we get back.
      * See SupportsAzureContentForDrawTarget.
      */
-    virtual already_AddRefed<DrawTarget>
+    static already_AddRefed<DrawTarget>
       CreateDrawTargetForSurface(gfxASurface *aSurface, const mozilla::gfx::IntSize& aSize);
 
     /*
      * Creates a SourceSurface for a gfxASurface. This function does no caching,
      * so the caller should cache the gfxASurface if it will be used frequently.
      * The returned surface keeps a reference to aTarget, so it is OK to keep the
      * surface, even if aTarget changes.
      * aTarget should not keep a reference to the returned surface because that

--- a/intl/lwbrk/nsJISx4051LineBreaker.cpp
+++ b/intl/lwbrk/nsJISx4051LineBreaker.cpp
@@ -542,20 +542,30 @@ GetClass(uint32_t u)
     /* H2 = 31,                           [H2] */ CLASS_BREAKABLE,
     /* H3 = 32,                           [H3] */ CLASS_BREAKABLE,
     /* JL = 33,                           [JL] */ CLASS_CHARACTER,
     /* JT = 34,                           [JT] */ CLASS_CHARACTER,
     /* JV = 35,                           [JV] */ CLASS_CHARACTER,
     /* CLOSE_PARENTHESIS = 36,            [CP] */ CLASS_CLOSE_LIKE_CHARACTER,
     /* CONDITIONAL_JAPANESE_STARTER = 37, [CJ] */ CLASS_CLOSE,
     /* HEBREW_LETTER = 38,                [HL] */ CLASS_CHARACTER,
-    /* REGIONAL_INDICATOR = 39,           [RI] */ CLASS_CHARACTER
+    /* REGIONAL_INDICATOR = 39,           [RI] */ CLASS_CHARACTER,
+    /* E_BASE = 40,                       [EB] */ CLASS_BREAKABLE,
+    /* E_MODIFIER = 41,                   [EM] */ CLASS_CHARACTER,
+    /* ZWJ = 42,                          [ZWJ]*/ CLASS_CHARACTER
   };
 
-  return sUnicodeLineBreakToClass[mozilla::unicode::GetLineBreakClass(u)];
+#if ENABLE_INTL_API
+  static_assert(U_LB_COUNT == mozilla::ArrayLength(sUnicodeLineBreakToClass),
+                "Gecko vs ICU LineBreak class mismatch");
+#endif
+
+  auto cls = mozilla::unicode::GetLineBreakClass(u);
+  MOZ_ASSERT(cls < mozilla::ArrayLength(sUnicodeLineBreakToClass));
+  return sUnicodeLineBreakToClass[cls];
 }
 
 static bool
 GetPair(int8_t c1, int8_t c2)
 {
   NS_ASSERTION(c1 < MAX_CLASSES ,"illegal classes 1");
   NS_ASSERTION(c2 < MAX_CLASSES ,"illegal classes 2");
 

--- a/js/src/doc/Debugger/Debugger.Object.md
+++ b/js/src/doc/Debugger/Debugger.Object.md
@@ -152,16 +152,24 @@ from its prototype:
     [`Debugger.Environment`][environment] instance representing the lexical
     environment enclosing the function when it was created. If the referent
     is a function proxy or not debuggee code, this is `undefined`.
 
 `errorMessageName`
 :  If the referent is an error created with an engine internal message template
    this is a string which is the name of the template; `undefined` otherwise.
 
+`errorLineNumber`
+:  If the referent is an Error object, this is the line number at which the
+   referent was created; `undefined`  otherwise.
+
+`errorColumnNumber`
+:  If the referent is an Error object, this is the column number at which the
+   referent was created; `undefined`  otherwise.
+
 `isBoundFunction`
 :   If the referent is a debuggee function, returns `true` if the referent is a
     bound function; `false` otherwise. If the referent is not a debuggee
     function, or not a function at all, returns `undefined` instead.
 
 `isArrowFunction`
 :   If the referent is a debuggee function, returns `true` if the referent is an
     arrow function; `false` otherwise. If the referent is not a debuggee

--- a/js/src/gc/Verifier.cpp
+++ b/js/src/gc/Verifier.cpp
@@ -549,13 +549,13 @@ CheckHeapTracer::check(AutoLockForExclus
     MOZ_RELEASE_ASSERT(failures == 0);
 }
 
 void
 js::gc::CheckHeapAfterGC(JSRuntime* rt)
 {
     AutoTraceSession session(rt, JS::HeapState::Tracing);
     CheckHeapTracer tracer(rt);
-    if (!tracer.init())
+    if (tracer.init())
         tracer.check(session.lock);
 }
 
 #endif /* JSGC_HASH_TABLE_CHECKS */

--- a/js/src/jit-test/tests/asm.js/bug1201124-simd-proxy.js
+++ b/js/src/jit-test/tests/asm.js/bug1201124-simd-proxy.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + "asm.js");
 load(libdir + "asserts.js");
 
 if (typeof newGlobal !== 'function' ||
     !isSimdAvailable() ||
     typeof SIMD === 'undefined')
 {
     quit();

--- a/js/src/jit-test/tests/asm.js/bug1268955-usestrict-semantics.js
+++ b/js/src/jit-test/tests/asm.js/bug1268955-usestrict-semantics.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 
 var scope = {};
 scope.mod = eval(`"use strict"; (function() { "use asm"; function f() {} return f; });`);
 
 scope.fun = scope.mod();
 
 var caught = false;
 for (let callee of ['mod', 'fun']) {

new file mode 100644
--- /dev/null
+++ b/js/src/jit-test/tests/asm.js/directives.txt
@@ -0,0 +1,1 @@
+|jit-test| test-also-noasmjs; test-also-wasm-baseline

--- a/js/src/jit-test/tests/asm.js/neuter-during-arguments-coercion.js
+++ b/js/src/jit-test/tests/asm.js/neuter-during-arguments-coercion.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + "asm.js");
 
 function f(stdlib, foreign, buffer)
 {
   "use asm";
   var i32 = new stdlib.Int32Array(buffer);
   function set(v)
   {

--- a/js/src/jit-test/tests/asm.js/simd-fbirds.js
+++ b/js/src/jit-test/tests/asm.js/simd-fbirds.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 /* -*- Mode: javascript; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 ; js-indent-level : 2 ; js-curly-indent-offset: 0 -*- */
 /* vim: set ts=4 et sw=4 tw=80: */
 
 // Author: Peter Jensen
 
 load(libdir + "asm.js");
 if (!isSimdAvailable() || typeof SIMD === 'undefined') {
     print("won't run tests as simd extensions aren't activated yet");

--- a/js/src/jit-test/tests/asm.js/simd-mandelbrot.js
+++ b/js/src/jit-test/tests/asm.js/simd-mandelbrot.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 /* -*- Mode: javascript; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 ; js-indent-level : 2 ; js-curly-indent-offset: 0 -*- */
 /* vim: set ts=2 et sw=2 tw=80: */
 
 // Mandelbrot using SIMD
 // Author: Peter Jensen, Intel Corporation
 
 load(libdir + "asm.js");
 if (!isSimdAvailable() || typeof SIMD === 'undefined') {

--- a/js/src/jit-test/tests/asm.js/testAddressErrors.js
+++ b/js/src/jit-test/tests/asm.js/testAddressErrors.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + "asm.js");
 
 setIonCheckGraphCoherency(false);
 setCachingEnabled(false);
 
 // constants
 var buf = new ArrayBuffer(BUF_MIN);
 

--- a/js/src/jit-test/tests/asm.js/testAtomic-effect.js
+++ b/js/src/jit-test/tests/asm.js/testAtomic-effect.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 if (!this.Atomics)
     quit();
 
 load(libdir + "asm.js");
 setJitCompilerOption('asmjs.atomics.enable', 1);
 
 var code = `
     "use asm";

--- a/js/src/jit-test/tests/asm.js/testBasic.js
+++ b/js/src/jit-test/tests/asm.js/testBasic.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + "asm.js");
 load(libdir + "asserts.js");
 
 assertAsmTypeFail(USE_ASM);
 assertAsmTypeFail(USE_ASM + 'return');
 assertAsmTypeFail(USE_ASM + 'function f() 0');
 assertAsmTypeFail(USE_ASM + 'function f(){}');
 assertAsmTypeFail(USE_ASM + 'function f(){} return 0');

--- a/js/src/jit-test/tests/asm.js/testBullet.js
+++ b/js/src/jit-test/tests/asm.js/testBullet.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 // Test a big fat asm.js module. First load/compile/cache bullet.js in a
 // separate process and then load it again in this process, which should be a
 // cache hit.
 
 setCachingEnabled(true);
 if (!isAsmJSCompilationAvailable())
     quit();
 

--- a/js/src/jit-test/tests/asm.js/testCaching.js
+++ b/js/src/jit-test/tests/asm.js/testCaching.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + "asm.js");
 
 setCachingEnabled(true);
 if (!isAsmJSCompilationAvailable() || !isCachingEnabled())
     quit();
 
 var body1 = "'use asm'; function f() { return 42 } function ff() { return 43 } return f";
 var m = new Function(body1);

--- a/js/src/jit-test/tests/asm.js/testCall.js
+++ b/js/src/jit-test/tests/asm.js/testCall.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + "asm.js");
 load(libdir + "asserts.js");
 
 assertAsmTypeFail(USE_ASM+"function f(){i=i|0} function g() { f(0) } return g");
 assertAsmTypeFail(USE_ASM+"function f(i){i=i|0} function g() { f() } return g");
 assertAsmTypeFail(USE_ASM+"function f(){} function g() { f()|0 } return g");
 assertAsmTypeFail(USE_ASM+"function f(){} function g() { +f() } return g");
 assertAsmTypeFail(USE_ASM+"function f(){} function g() { return f() } return g");

--- a/js/src/jit-test/tests/asm.js/testCloning.js
+++ b/js/src/jit-test/tests/asm.js/testCloning.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + "asm.js");
 
 setCachingEnabled(true);
 
 var code = asmCompile(USE_ASM + "function g() { return 42 } return g");
 assertEq(asmLink(code)(), 42);
 assertEq(asmLink(code)(), 42);
 

--- a/js/src/jit-test/tests/asm.js/testCompoundPlusMinus.js
+++ b/js/src/jit-test/tests/asm.js/testCompoundPlusMinus.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + "asm.js");
 
 assertAsmTypeFail(USE_ASM + "function f(i,j,k) { i=i|0;j=+j;k=+k; return (i+(j+k))|0 } return f");
 assertAsmTypeFail(USE_ASM + "function f(i,j,k) { i=i|0;j=j|0;k=+k; return +((i+j)+k) } return f");
 assertAsmTypeFail('imp', USE_ASM + "var ffi=imp.ffi; function f(i) { i=i|0; return (i+ffi())|0 } return f");
 
 assertEq(asmLink(asmCompile(USE_ASM + "function f(i,j,k) { i=i|0;j=j|0;k=k|0; return (i+j+k)|0 } return f"))(1,2,3), 6);
 assertEq(asmLink(asmCompile(USE_ASM + "function f(i,j,k) { i=i|0;j=j|0;k=k|0; return (i+j-k)|0 } return f"))(1,2,3), 0);

--- a/js/src/jit-test/tests/asm.js/testControlFlow.js
+++ b/js/src/jit-test/tests/asm.js/testControlFlow.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + "asm.js");
 
 assertEq(asmLink(asmCompile(USE_ASM + "function f(i,j) { i=i|0;j=+j; if (i) return j; return j+1.0 } return f"))(0, 1.2), 1.2+1.0);
 assertEq(asmLink(asmCompile(USE_ASM + "function f(i,j) { i=i|0;j=+j; if (i) return j; return +~~i } return f"))(1,1.4), 1.4);
 assertEq(asmLink(asmCompile(USE_ASM + "function f(i,j) { i=i|0;j=j|0; if (i) return j^0; return i^1 } return f"))(1, 1), 1);
 assertEq(asmLink(asmCompile(USE_ASM + "function f(i,j) { i=i|0;j=j|0; if (i) return j^0; return i|0 } return f"))(1,8), 8);
 assertEq(asmLink(asmCompile(USE_ASM + "function f(i) { i=i|0; if ((i|0) == 0) return 10; else if ((i|0) == 1) return 12; else if ((i|0) == 2) return 14; return 0} return f"))(2), 14);
 assertEq(asmLink(asmCompile(USE_ASM + "function f(i) { i=i|0; if ((i|0) == 0) return 10; else if ((i|0) == 1) return 12; else if ((i|0) == 2) return 14; else return 16; return 0} return f"))(3), 16);

--- a/js/src/jit-test/tests/asm.js/testExpressions.js
+++ b/js/src/jit-test/tests/asm.js/testExpressions.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + "asm.js");
 
 assertAsmTypeFail(USE_ASM + "function f() { var i=0,j=0.0; return (i+j)|0 } return f");
 assertAsmTypeFail(USE_ASM + "function f() { var i=0.0,j=0; return (i+j)|0 } return f");
 assertAsmTypeFail(USE_ASM + "function f() { var i=0,j=0.0; return (i-j)|0 } return f");
 assertAsmTypeFail(USE_ASM + "function f() { var i=0.0,j=0; return (i-j)|0 } return f");
 assertAsmTypeFail(USE_ASM + "function f() { var i=0,j=0.0; return (i*j)|0 } return f");
 assertAsmTypeFail(USE_ASM + "function f() { var i=0.0,j=0; return (i*j)|0 } return f");

--- a/js/src/jit-test/tests/asm.js/testFFI.js
+++ b/js/src/jit-test/tests/asm.js/testFFI.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + "asm.js");
 load(libdir + "asserts.js");
 
 function ffi(a,b,c,d) {
     return a+b+c+d;
 }
 
 var f = asmLink(asmCompile('global','imp', USE_ASM + 'var ffi=imp.ffi; function g() { return 1 } function f() { var i=0; i=g()|0; return ((ffi(4,5,6,7)|0)+i)|0 } return f'), null, {ffi:ffi});

--- a/js/src/jit-test/tests/asm.js/testFastHeapAccess.js
+++ b/js/src/jit-test/tests/asm.js/testFastHeapAccess.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + "asm.js");
 
 var code = asmCompile('glob', 'imp', 'b', USE_ASM + HEAP_IMPORTS + 'function f(i,j) {i=i|0;j=j|0; u32[((i<<2)+32 & 0xffff)>>2] = j } return f');
 var f = asmLink(code, this, null, BUF_64KB);
 for (var i = 0; i < 100; i++)
     f(i, i);
 var u32 = new Uint32Array(BUF_64KB);
 for (var i = 0; i < 100; i++)

--- a/js/src/jit-test/tests/asm.js/testFloat32.js
+++ b/js/src/jit-test/tests/asm.js/testFloat32.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + "asm.js");
 const TO_FLOAT32 = "var toF = glob.Math.fround;";
 const HEAP32 = "var f32 = new glob.Float32Array(heap);";
 const HEAP64 = "var f64 = new glob.Float64Array(heap);"
 var heap = new ArrayBuffer(BUF_MIN);
 
 // Module linking
 assertAsmLinkAlwaysFail(asmCompile('glob', USE_ASM + TO_FLOAT32 + "function f() {} return f"), null);

--- a/js/src/jit-test/tests/asm.js/testFloatingPoint.js
+++ b/js/src/jit-test/tests/asm.js/testFloatingPoint.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + "asm.js");
 
 assertEq(asmLink(asmCompile(USE_ASM + "function f() { return 1.1 } return f"))(), 1.1);
 assertEq(asmLink(asmCompile(USE_ASM + "function f(i) { i=i|0; return +(+(i|0) + .1) } return f"))(1), 1.1);
 assertEq(asmLink(asmCompile(USE_ASM + "function f(d) { d=+d; return +d } return f"))(1.1), 1.1);
 assertEq(asmLink(asmCompile(USE_ASM + "function f(d,e) { d=+d;e=+e; return +(d+e) } return f"))(1.0, .1), 1.1);
 assertEq(asmLink(asmCompile(USE_ASM + "function f(i,e) { i=i|0;e=+e; return +(+~~i+e) } return f"))(1, .1), 1.1);
 assertEq(asmLink(asmCompile(USE_ASM + "function f(d,i) { d=+d;i=i|0; return +(d + +(i|0)) } return f"))(.1, 1), 1.1);

--- a/js/src/jit-test/tests/asm.js/testFunctionPtr.js
+++ b/js/src/jit-test/tests/asm.js/testFunctionPtr.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + "asm.js");
 
 assertAsmTypeFail('imp', USE_ASM + "function f() {} var imp=[f]; return f");
 assertAsmTypeFail(USE_ASM + "function f() {} var eval=[f]; return f");
 assertAsmTypeFail(USE_ASM + "var tbl=0; function f() {} var tbl=[f]; return f");
 assertAsmTypeFail(USE_ASM + "function f() {} var tbl; return f");
 assertAsmTypeFail(USE_ASM + "function f() {} var tbl=[]; return f");
 assertAsmTypeFail(USE_ASM + "function f() {} var tbl=[f,f,f]; return f");

--- a/js/src/jit-test/tests/asm.js/testGlobals.js
+++ b/js/src/jit-test/tests/asm.js/testGlobals.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + "asm.js");
 load(libdir + "asserts.js");
 
 assertAsmTypeFail(USE_ASM + "var i; function f(){} return f");
 assertEq(asmLink(asmCompile(USE_ASM + "var i=0; function f(){} return f"))(), undefined);
 assertEq(asmLink(asmCompile(USE_ASM + "const i=0; function f(){} return f"))(), undefined);
 assertEq(asmLink(asmCompile(USE_ASM + "var i=42; function f(){ return i|0 } return f"))(), 42);
 assertEq(asmLink(asmCompile(USE_ASM + "const i=42; function f(){ return i|0 } return f"))(), 42);

--- a/js/src/jit-test/tests/asm.js/testHeapAccess.js
+++ b/js/src/jit-test/tests/asm.js/testHeapAccess.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + "asm.js");
 
 assertAsmTypeFail('glob', 'imp', 'b', USE_ASM + HEAP_IMPORTS + 'function f() { i32[0>>2] = 4.0; return i32[0>>2]|0; } return f');
 assertAsmTypeFail('glob', 'imp', 'b', USE_ASM + HEAP_IMPORTS + 'function f() { f32[0>>2] = 4; return +f32[0>>2]; } return f');
 
 assertAsmTypeFail('glob', 'imp', 'b', USE_ASM + HEAP_IMPORTS + 'function f() { var x=0,y=0; return i8[x+y]|0 } return f');
 assertAsmTypeFail('glob', 'imp', 'b', USE_ASM + HEAP_IMPORTS + 'function f() { var x=0,y=0; return u8[x+y]|0 } return f');
 

--- a/js/src/jit-test/tests/asm.js/testLinkErrorAssert.js
+++ b/js/src/jit-test/tests/asm.js/testLinkErrorAssert.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 // This test should not assert.
 
 function asmModule(g, foreign, heap) {
     "use asm";
     let HEAP8 = new g.Int8Array(heap);
 
     function f() { return 99; } 
     return {f: f};

--- a/js/src/jit-test/tests/asm.js/testLiterals.js
+++ b/js/src/jit-test/tests/asm.js/testLiterals.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + 'asm.js');
 
 assertAsmTypeFail(USE_ASM + 'function f(d) { d=+d; var e=0; e=d; return +e } return f');
 assertAsmTypeFail(USE_ASM + 'function f(d) { d=+d; var e=1e1; e=d; return +e } return f');
 assertAsmTypeFail(USE_ASM + 'function f(d) { d=+d; var e=+0; e=d; return +e } return f');
 assertEq(asmLink(asmCompile(USE_ASM + 'function f() { var e=-0; return +e } return f'))(-0), -0);
 assertEq(asmLink(asmCompile(USE_ASM + 'function f() { var e=-0.0; return +e } return f'))(-0), -0);
 assertEq(asmLink(asmCompile(USE_ASM + 'function f(d) { d=+d; var e=0.0; e=d; return +e } return f'))(0.1), 0.1);

--- a/js/src/jit-test/tests/asm.js/testMathLib.js
+++ b/js/src/jit-test/tests/asm.js/testMathLib.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + "asm.js");
 
 function testUnary(f, g) {
     var numbers = [NaN, Infinity, -Infinity, -10000, -3.4, -0, 0, 3.4, 10000];
     for (n of numbers)
         assertEq(f(n), g(n));
 }
 

--- a/js/src/jit-test/tests/asm.js/testModuleFunctions.js
+++ b/js/src/jit-test/tests/asm.js/testModuleFunctions.js
@@ -1,9 +1,9 @@
-// |jit-test| test-also-noasmjs
+
 function testUniqueness(asmJSModule) {
     var f = asmJSModule();
     var g = asmJSModule();
     assertEq(f === g, false);
     f.x = 4;
     assertEq(f.x, 4);
     assertEq(g.x, undefined);
 }

--- a/js/src/jit-test/tests/asm.js/testNeuter.js
+++ b/js/src/jit-test/tests/asm.js/testNeuter.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + "asm.js");
 load(libdir + "asserts.js");
 
 if (!isAsmJSCompilationAvailable())
     quit();
 
 var m = asmCompile('stdlib', 'foreign', 'buffer',
                   `"use asm";

--- a/js/src/jit-test/tests/asm.js/testParallelCompile.js
+++ b/js/src/jit-test/tests/asm.js/testParallelCompile.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + "asm.js");
 
 if (!isAsmJSCompilationAvailable())
     quit();
 
 var module = "'use asm';\n";
 for (var i = 0; i < 100; i++) {
     module += "function f" + i + "(i) {\n";

--- a/js/src/jit-test/tests/asm.js/testProfiling.js
+++ b/js/src/jit-test/tests/asm.js/testProfiling.js
@@ -1,11 +1,15 @@
 load(libdir + "asm.js");
 load(libdir + "asserts.js");
 
+// Run test only for asm.js
+if (!isAsmJSCompilationAvailable())
+    quit();
+
 // Single-step profiling currently only works in the ARM simulator
 if (!getBuildConfiguration()["arm-simulator"])
     quit();
 
 function checkSubSequence(got, expect)
 {
     var got_i = 0;
     EXP: for (var exp_i = 0; exp_i < expect.length; exp_i++) {

--- a/js/src/jit-test/tests/asm.js/testRangeAnalysis.js
+++ b/js/src/jit-test/tests/asm.js/testRangeAnalysis.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 // Bug 894781
 function m(stdlib)
 {
   "use asm";
   var abs = stdlib.Math.abs;
   function f(d)
   {
     d = +d;

--- a/js/src/jit-test/tests/asm.js/testSource.js
+++ b/js/src/jit-test/tests/asm.js/testSource.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 setCachingEnabled(true);
 
 (function() {
 /*
  * NO ARGUMENT
  */
 
 function f0() {

--- a/js/src/jit-test/tests/asm.js/testStackWalking.js
+++ b/js/src/jit-test/tests/asm.js/testStackWalking.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + "asm.js");
 load(libdir + "asserts.js");
 
 function matchStack(stackString, stackArray)
 {
     var match = 0;
     for (name of stackArray) {
         match = stackString.indexOf(name, match);

--- a/js/src/jit-test/tests/asm.js/testUseAsmWarnings.js
+++ b/js/src/jit-test/tests/asm.js/testUseAsmWarnings.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + "asm.js");
 
 assertAsmDirectiveFail("'use asm'");
 assertAsmDirectiveFail("eval('\"use asm\";');");
 assertAsmDirectiveFail("{ eval('\"use asm\";'); }");
 assertAsmDirectiveFail("if (Math) { 'use asm'; }");
 assertAsmDirectiveFail("function f(){ { 'use asm'; } }");
 assertAsmDirectiveFail("function f(){ ; 'use asm'; } }");

--- a/js/src/jit-test/tests/asm.js/testX86ByteStore.js
+++ b/js/src/jit-test/tests/asm.js/testX86ByteStore.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-noasmjs
 load(libdir + "asm.js");
 
 var body =
 '   "use asm";\
     var i8=new global.Int8Array(buffer);\
     function g(i,j,k) {\
         i=i|0;\
         j=j|0;\

new file mode 100644
--- /dev/null
+++ b/js/src/jit-test/tests/debug/Object-errorLineNumber-errorColumnNumber.js
@@ -0,0 +1,55 @@
+// Debugger.Object.prototype.{errorLineNumber,errorColumnNumber} return the
+// line number and column number associated with some error object.
+
+var g = newGlobal();
+var dbg = new Debugger();
+var gw = dbg.addDebuggee(g);
+
+var syntaxError = gw.executeInGlobal("\nlet a, a;").throw;
+assertEq(syntaxError.errorLineNumber, 2);
+assertEq(syntaxError.errorColumnNumber, 7);
+
+var typeError = gw.executeInGlobal("\n1 + f();").throw;
+assertEq(typeError.errorLineNumber, 2);
+assertEq(typeError.errorColumnNumber, 1);
+
+// Custom errors have no line/column numbers .
+var customError = gw.executeInGlobal("\nthrow 1;").throw;
+assertEq(customError.errorLineNumber, undefined);
+assertEq(customError.errorColumnNumber, undefined);
+
+customError = gw.executeInGlobal("\nthrow { errorLineNumber: 10, errorColumnNumber: 20 };").throw;
+assertEq(customError.errorLineNumber, undefined);
+assertEq(customError.errorColumnNumber, undefined);
+
+customError = gw.executeInGlobal("\nthrow { lineNumber: 10, columnNumber: 20 };").throw;
+assertEq(customError.errorLineNumber, undefined);
+assertEq(customError.errorColumnNumber, undefined);
+
+// Ensure that the method works across globals.
+g.eval(`var g = newGlobal();
+        g.eval('var err; \\n' +
+               'try {\\n' +
+               '  f();\\n' +
+               '} catch (e) {\\n' +
+               '  err = e;\\n' +
+               '}');
+        var err2 = g.err;`);
+var otherGlobalError = gw.executeInGlobal("throw err2").throw;
+assertEq(otherGlobalError.errorLineNumber, 3);
+assertEq(otherGlobalError.errorColumnNumber, 3);
+
+// Ensure that non-error objects return undefined.
+const Args = [
+    "1",
+    "'blah'",
+    "({})",
+    "[]",
+    "() => 1"
+]
+
+for (let arg of Args) {
+    let nonError = gw.executeInGlobal(`${arg}`).return;
+    assertEq(nonError.errorLineNumber, undefined);
+    assertEq(nonError.errorColumnNumber, undefined);
+}

new file mode 100644
--- /dev/null
+++ b/js/src/jit-test/tests/gc/bug-1315946.js
@@ -0,0 +1,14 @@
+if (!('oomTest' in this))
+    quit();
+
+// Don't run a full oomTest because it takes ages - a few iterations are
+// sufficient to trigger the bug.
+let i = 0;
+
+oomTest(Function(`
+    if (i < 10) {
+        i++;
+        gczeal(15,1);
+        foo;
+    }
+`));

new file mode 100644
--- /dev/null
+++ b/js/src/jit-test/tests/ion/bug1314438.js
@@ -0,0 +1,6 @@
+
+function g(x) {
+    return (-1 % x && Math.cos(8) >>> 0);
+}
+g(2);
+assertEq(uneval(g(-1)), "-0");

new file mode 100644
--- /dev/null
+++ b/js/src/jit-test/tests/ion/bug1314545.js
@@ -0,0 +1,31 @@
+function f() {
+    Object.prototype[0] = 10;
+
+    var arr = [];
+    for (var i=3; i<20; i++) {
+        arr[0] = i;
+        Object.freeze(arr);
+        while (!inIon()) {}
+    }
+    assertEq(arr[0], 3);
+}
+f();
+
+function g() {
+    var c = 0;
+    Object.defineProperty(Object.prototype, 18, {set: function() { c++; }});
+
+    var arrays = [];
+    for (var i=0; i<2; i++)
+        arrays.push([1, 2]);
+
+    for (var i=0; i<20; i++) {
+        arrays[0][i] = 1;
+        arrays[1][i] = 2;
+        if (i === 0)
+            Object.freeze(arrays[0]);
+        while (!inIon()) {}
+    }
+    assertEq(c, 2);
+}
+g();

--- a/js/src/jit-test/tests/wasm/backtrace.js
+++ b/js/src/jit-test/tests/wasm/backtrace.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 var code = `(module
   (import $i "env" "test")
   (func $t (call $i))
   (export "test" $t)
 )`;
 var mod = wasmEvalText(code, {

--- a/js/src/jit-test/tests/wasm/basic.js
+++ b/js/src/jit-test/tests/wasm/basic.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 // ----------------------------------------------------------------------------
 // exports
 
 var o = wasmEvalText('(module)').exports;
 assertEq(Object.getOwnPropertyNames(o).length, 0);
 

--- a/js/src/jit-test/tests/wasm/bce.js
+++ b/js/src/jit-test/tests/wasm/bce.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 mem='\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f'+
     '\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff'+
     '\x00'.repeat(65488) +
     '\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff'
 
 print (mem.lengt)

--- a/js/src/jit-test/tests/wasm/binary.js
+++ b/js/src/jit-test/tests/wasm/binary.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 load(libdir + "wasm-binary.js");
 
 const CompileError = WebAssembly.CompileError;
 
 const magicError = /failed to match magic number/;
 const unknownSection = /expected user-defined section/;
 

--- a/js/src/jit-test/tests/wasm/comments.js
+++ b/js/src/jit-test/tests/wasm/comments.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 // sanity check
 assertErrorMessage(() => wasmEvalText(''), SyntaxError, /parsing wasm text/);
 
 // single line comment
 var o = wasmEvalText('(module (func)) ;; end');
 var o = wasmEvalText('(module (func)) ;; end\n');

--- a/js/src/jit-test/tests/wasm/compiler-frame-depth.js
+++ b/js/src/jit-test/tests/wasm/compiler-frame-depth.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 // Ensures that the postorder allows us to have very deep expression trees.
 
 var expr = '(get_local 0)';
 
 for (var i = 1000; i --> 0; ) {
     expr = `(f32.neg ${expr})`;

--- a/js/src/jit-test/tests/wasm/const.js
+++ b/js/src/jit-test/tests/wasm/const.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 function testConst(type, str, expect) {
     if (type === 'i64')
         wasmFullPassI64(`(module (func (result i64) (i64.const ${str})) (export "run" 0))`, expect);
     else
         wasmFullPass(`(module (func (result ${type}) (${type}.const ${str})) (export "run" 0))`, expect);
 }

--- a/js/src/jit-test/tests/wasm/control-flow.js
+++ b/js/src/jit-test/tests/wasm/control-flow.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 const RuntimeError = WebAssembly.RuntimeError;
 
 // ----------------------------------------------------------------------------
 // if
 
 // Condition is an int32

--- a/js/src/jit-test/tests/wasm/conversion.js
+++ b/js/src/jit-test/tests/wasm/conversion.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 function testConversion(resultType, opcode, paramType, op, expect) {
   if (paramType === 'i64') {
     // i64 cannot be imported, so we use a wrapper function.
     wasmFullPass(`(module
                     (func (param i64) (result ${resultType}) (${resultType}.${opcode}/i64 (get_local 0)))
                     (export "run" 0))`, expect, {}, createI64(op));

new file mode 100644
--- /dev/null
+++ b/js/src/jit-test/tests/wasm/directives.txt
@@ -0,0 +1,1 @@
+|jit-test| test-also-wasm-baseline

--- a/js/src/jit-test/tests/wasm/errors.js
+++ b/js/src/jit-test/tests/wasm/errors.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 load(libdir + "wasm-binary.js");
 
 const Module = WebAssembly.Module;
 const Instance = WebAssembly.Instance;
 const RuntimeError = WebAssembly.RuntimeError;
 
 function isWasmFunction(name) {

--- a/js/src/jit-test/tests/wasm/extract-code.js
+++ b/js/src/jit-test/tests/wasm/extract-code.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 var module = new WebAssembly.Module(wasmTextToBinary(`(module (func (nop)))`));
 var exp = wasmExtractCode(module);
 assertEq(exp.code instanceof Uint8Array, true);
 assertEq(Array.isArray(exp.segments), true);
 var funcs = exp.segments.filter(s => s.kind === 0);
 assertEq(funcs.length, 1);

--- a/js/src/jit-test/tests/wasm/fac.js
+++ b/js/src/jit-test/tests/wasm/fac.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 // This is fac-opt from fac.wast in the official testsuite, changed to use
 // i32 instead of i64.
 assertEq(wasmEvalText(`(module
   (func $fac-opt (param i32) (result i32)
     (local i32)
     (set_local 1 (i32.const 1))

--- a/js/src/jit-test/tests/wasm/float.js
+++ b/js/src/jit-test/tests/wasm/float.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 wasmFullPass('(module (func (result f32) (f32.const -1)) (export "run" 0))', -1);
 wasmFullPass('(module (func (result f32) (f32.const 1)) (export "run" 0))', 1);
 wasmFullPass('(module (func (result f64) (f64.const -2)) (export "run" 0))', -2);
 wasmFullPass('(module (func (result f64) (f64.const 2)) (export "run" 0))', 2);
 wasmFullPass('(module (func (result f64) (f64.const 4294967296)) (export "run" 0))', 4294967296);
 wasmFullPass('(module (func (result f32) (f32.const 1.5)) (export "run" 0))', 1.5);

--- a/js/src/jit-test/tests/wasm/full-cycle.js
+++ b/js/src/jit-test/tests/wasm/full-cycle.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 wasmFullPass(`(module
     (func $test (result i32) (param i32) (param i32) (i32.add (get_local 0) (get_local 1)))
     (func $run (result i32) (call $test (i32.const 1) (i32.const ${Math.pow(2, 31) - 1})))
     (export "run" $run)
 )`, -Math.pow(2, 31));
 

--- a/js/src/jit-test/tests/wasm/globals.js
+++ b/js/src/jit-test/tests/wasm/globals.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 const { Instance, Module } = WebAssembly;
 
 // Locally-defined globals
 assertErrorMessage(() => wasmEvalText(`(module (global))`), SyntaxError, /parsing/);
 assertErrorMessage(() => wasmEvalText(`(module (global i32))`), SyntaxError, /parsing/);
 assertErrorMessage(() => wasmEvalText(`(module (global (mut i32)))`), SyntaxError, /parsing/);

--- a/js/src/jit-test/tests/wasm/grow-memory.js
+++ b/js/src/jit-test/tests/wasm/grow-memory.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 function linearModule(min, max, ops) {
   var opsText = ops.map(function (op) {
     if (op[0] == "CM") {
       res = `(if i32 (i32.ne (current_memory) (i32.const ${op[1]}))
                   (i32.load offset=10 (i32.const 4294967295))
                   (i32.const 0))`

--- a/js/src/jit-test/tests/wasm/import-export.js
+++ b/js/src/jit-test/tests/wasm/import-export.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + 'wasm.js');
 
 const Module = WebAssembly.Module;
 const Instance = WebAssembly.Instance;
 const Memory = WebAssembly.Memory;
 const Table = WebAssembly.Table;
 
 const mem1Page = new Memory({initial:1});

--- a/js/src/jit-test/tests/wasm/integer.js
+++ b/js/src/jit-test/tests/wasm/integer.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 assertEq(wasmEvalText('(module (func (result i32) (i32.const -1)) (export "" 0))').exports[""](), -1);
 assertEq(wasmEvalText('(module (func (result i32) (i32.const -2147483648)) (export "" 0))').exports[""](), -2147483648);
 assertEq(wasmEvalText('(module (func (result i32) (i32.const 4294967295)) (export "" 0))').exports[""](), -1);
 
 function testUnary(type, opcode, op, expect) {
     var fullPass = wasmFullPass;

--- a/js/src/jit-test/tests/wasm/js-reexport.js
+++ b/js/src/jit-test/tests/wasm/js-reexport.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 const Module = WebAssembly.Module;
 const Instance = WebAssembly.Instance;
 const Memory = WebAssembly.Memory;
 const Table = WebAssembly.Table;
 
 function accum(...args) {

--- a/js/src/jit-test/tests/wasm/memory-aliasing.js
+++ b/js/src/jit-test/tests/wasm/memory-aliasing.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 var i = wasmEvalText(
 `(module
    (memory 1) (data (i32.const 0) "\\01\\02\\03\\04\\05\\06\\07\\08")
    (func $off1 (param $base i32) (result i32)
      (i32.add
        (i32.load8_u (get_local $base))

--- a/js/src/jit-test/tests/wasm/memory.js
+++ b/js/src/jit-test/tests/wasm/memory.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 const RuntimeError = WebAssembly.RuntimeError;
 
 function loadModule(type, ext, offset, align) {
     return wasmEvalText(
     `(module
        (memory 1)

new file mode 100644
--- /dev/null
+++ b/js/src/jit-test/tests/wasm/regress/baseline-pop-along-edge.js
@@ -0,0 +1,68 @@
+// Bug 1316181
+
+load(libdir + "wasm.js");
+
+// There are locals with different values here to ensure that the
+// get_local at the end picks up the right one even if the stack might
+// have become unbalanced by a failure to adjust SP along the branch
+// edge.  The logic is that we use SP-relative addressing, and if the
+// actual SP is not what the compiler thinks it is we will read
+// something other than the expected value.
+
+var o = wasmEvalText(
+    `(module
+      (func (result i32)
+       (local $v0 i32)
+       (local $v1 i32)
+       (local $v2 i32)
+       (local $v3 i32)
+       (local $v4 i32)
+       (local $v5 i32)
+       (local $v6 i32)
+       (local $v7 i32)
+       (local $res i32)
+       (set_local $v0 (i32.const 0xDEADBEEF))
+       (set_local $v1 (i32.const 0xFDEADBEE))
+       (set_local $v2 (i32.const 0xEFDEADBE))
+       (set_local $v3 (i32.const 0xEEFDEADB))
+       (set_local $v4 (i32.const 0xBEEFDEAD))
+       (set_local $v5 (i32.const 0xDBEEFDEA))
+       (set_local $v6 (i32.const 0xADBEEFDE))
+       (set_local $v7 (i32.const 0xEADBEEFD))
+       (block $b
+	(set_local $res
+	 (i32.add
+	  (i32.add (i32.const 1) (i32.const 2))
+	  (i32.add
+	   (i32.add (i32.const 3) (i32.const 4))
+	   (i32.add
+	    (i32.add (i32.const 5) (i32.const 6))
+	    (i32.add
+	     (i32.add (i32.const 7) (i32.const 8))
+	     (i32.add
+	      (i32.add (i32.const 9) (i32.const 10))
+	      (i32.add
+	       (i32.add (i32.const 11) (i32.const 12))
+	       (i32.add
+		(i32.add (i32.const 13) (i32.const 14))
+		(i32.add
+		 (i32.add (i32.const 15) (i32.const 16))
+		 (i32.add
+		  (i32.add (i32.const 17) (i32.const 18))
+		  (i32.add
+		   (i32.add (i32.const 19) (i32.const 20))
+		   (i32.add
+		    (i32.add (i32.const 21) (i32.const 22))
+		    (i32.add
+		     (i32.add (i32.const 23) (i32.const 24))
+		     (i32.add
+		      (i32.add (i32.const 25) (i32.const 26))
+		      (i32.add
+		       (i32.add (i32.const 27) (i32.const 28))
+		       (i32.add
+			(i32.add (i32.const 29) (i32.const 30))
+			(br_if $b (i32.const 31) (i32.const 1)))))))))))))))))))
+       (return (get_local $v3)))
+      (export "a" 0))`).exports;
+
+assertEq(o["a"](), 0xEEFDEADB|0);

new file mode 100644
--- /dev/null
+++ b/js/src/jit-test/tests/wasm/regress/directives.txt
@@ -0,0 +1,1 @@
+|jit-test| test-also-wasm-baseline

--- a/js/src/jit-test/tests/wasm/regress/misc-control-flow.js
+++ b/js/src/jit-test/tests/wasm/regress/misc-control-flow.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 wasmFailValidateText(`(module
    (func (result i32) (param i32)
      (loop (if (i32.const 0) (br 0)) (get_local 0)))
    (export "" 0)
 )`, /unused values not explicitly dropped by end of block/);
 

new file mode 100644
--- /dev/null
+++ b/js/src/jit-test/tests/wasm/regress/pass-stack-int64.js
@@ -0,0 +1,17 @@
+load(libdir + "wasm.js");
+
+var params = '';
+var locals = '';
+for (let i = 0; i < 20; i++) {
+    params += '(param i64) ';
+    locals += `(get_local ${i}) `;
+}
+
+wasmEvalText(`
+(module
+    (func
+        ${params}
+        (call 0 ${locals})
+    )
+)
+`);

--- a/js/src/jit-test/tests/wasm/regress/regalloc-muli64.js
+++ b/js/src/jit-test/tests/wasm/regress/regalloc-muli64.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 // Bug 1298808.
 assertEq(wasmEvalText(`(module
     (func
         (result i32)
         (i32.wrap/i64
             (i64.mul

--- a/js/src/jit-test/tests/wasm/regress/reserve-enough.js
+++ b/js/src/jit-test/tests/wasm/regress/reserve-enough.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 // Bug 1281131 - be sure to reserve enough stack space
 
 wasmEvalText(
 `(module
   (func $func0
    ${loopy(100)}

--- a/js/src/jit-test/tests/wasm/regress/reserve-joinreg.js
+++ b/js/src/jit-test/tests/wasm/regress/reserve-joinreg.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 // Bug 1280933, excerpted from binary test case provided there.
 
 wasmEvalText(
 `(module
   (func $func0 (param $arg0 i32) (result i32) (local $var0 i64)
 	(set_local $var0 (i64.extend_u/i32 (get_local $arg0)))

--- a/js/src/jit-test/tests/wasm/regress/select-any.js
+++ b/js/src/jit-test/tests/wasm/regress/select-any.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 // Bug 1280921
 
 var m1 = wasmEvalText(
 `(module
   (type $type0 (func))
   (func $func0

--- a/js/src/jit-test/tests/wasm/regress/shift-counts.js
+++ b/js/src/jit-test/tests/wasm/regress/shift-counts.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 // Bug 1280926, extracted from binary
 
 wasmEvalText(
 `(module
   (type $type0 (func (result i32)))
   (export "" $func0)

--- a/js/src/jit-test/tests/wasm/regress/teavm-bugs.js
+++ b/js/src/jit-test/tests/wasm/regress/teavm-bugs.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 // Register allocation issue with LCompareI64AndBranch.
 let params = '';
 let locals = '';
 let tests = '(i64.const 0)';
 
 for (let i = 15; i --> 0;) {

--- a/js/src/jit-test/tests/wasm/regress/too-large-frame.js
+++ b/js/src/jit-test/tests/wasm/regress/too-large-frame.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 // Bug 1280934, equivalent test case.
 
 try {
 
 wasmEvalText(
 `(module

--- a/js/src/jit-test/tests/wasm/resizing.js
+++ b/js/src/jit-test/tests/wasm/resizing.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 const Module = WebAssembly.Module;
 const Instance = WebAssembly.Instance;
 const Table = WebAssembly.Table;
 const Memory = WebAssembly.Memory;
 const RuntimeError = WebAssembly.RuntimeError;
 

--- a/js/src/jit-test/tests/wasm/spec.js
+++ b/js/src/jit-test/tests/wasm/spec.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 // This is meant to be a small and dumb interpreter for wast files. Either it
 // is imported by another script, which needs to define an array of arguments
 // called importedArgs, or args need to be passed to the command line.
 //
 // Possible arguments include:
 // -d           enable debug verbose mode
@@ -393,31 +392,43 @@ function exec(e) {
 
             i32[0] = res.nan_low;
             i32[1] = res.nan_high;
             assert(Number.isNaN(f64[0]) || Number.isNaN(f32[0]), "assert_return_nan test failed.");
         }
         return;
     }
 
-    if (exprName === "assert_invalid") {
+    if (exprName === "assert_invalid" || exprName === "assert_malformed") {
         let moduleText = e.list[1].toString();
         let errMsg = e.list[2];
         if (errMsg) {
-            assert(errMsg.quoted, "assert_invalid second argument must be a string");
+            assert(errMsg.quoted, "assert_invalid/malformed second argument must be a string");
             errMsg.quoted = false;
         }
+
         // assert_invalid tests both the decoder *and* the parser itself.
+        let text;
         try {
-            assertEq(WebAssembly.validate(wasmTextToBinary(moduleText)), false, "assert_invalid failed");
+            text = wasmTextToBinary(moduleText);
         } catch(e) {
             if (/wasm text error/.test(e.toString()))
                 return;
-            throw e;
         }
+
+        assertEq(WebAssembly.validate(text), false, "assert_invalid failed");
+
+        let caught = false;
+        try {
+            new WebAssembly.Module(text)
+        } catch (e) {
+            caught = true;
+            debug("Caught", e.toString(), ", expected:", errMsg);
+        }
+        assertEq(caught, true);
         return;
     }
 
     if (exprName === "assert_soft_invalid") {
         let moduleText = e.list[1].toString();
         let errMsg = e.list[2];
         if (errMsg) {
             assert(errMsg.quoted, "assert_soft_invalid second argument must be a string");

--- a/js/src/jit-test/tests/wasm/spec/address.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/address.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['address.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/binary.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/binary.wast.js
@@ -1,4 +1,1 @@
-// |jit-test| test-also-wasm-baseline
-// TODO: binary text format.
-quit();
 var importedArgs = ['binary.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/block.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/block.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['block.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/br.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/br.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['br.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/br_if.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/br_if.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['br_if.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/br_table.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/br_table.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['br_table.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/break-drop.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/break-drop.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['break-drop.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/call.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/call.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['call.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/call_indirect.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/call_indirect.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['call_indirect.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/comments.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/comments.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['comments.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/conversions.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/conversions.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['conversions.wast']; load(scriptdir + '../spec.js');

new file mode 100644
--- /dev/null
+++ b/js/src/jit-test/tests/wasm/spec/directives.txt
@@ -0,0 +1,1 @@
+|jit-test| test-also-wasm-baseline

--- a/js/src/jit-test/tests/wasm/spec/endianness.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/endianness.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['endianness.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/exports.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/exports.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['exports.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/f32.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/f32.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['f32.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/f32_cmp.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/f32_cmp.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['f32_cmp.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/f64.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/f64.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['f64.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/f64_cmp.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/f64_cmp.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['f64_cmp.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/fac.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/fac.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['fac.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/float_exprs.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/float_exprs.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['float_exprs.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/float_literals.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/float_literals.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['float_literals.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/float_memory.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/float_memory.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['float_memory.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/float_misc.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/float_misc.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['float_misc.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/forward.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/forward.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['forward.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/func.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/func.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['func.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/func_ptrs.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/func_ptrs.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['func_ptrs.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/get_local.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/get_local.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['get_local.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/globals.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/globals.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['globals.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/i32.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/i32.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['i32.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/i64.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/i64.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['i64.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/import_tests.sh
+++ b/js/src/jit-test/tests/wasm/spec/import_tests.sh
@@ -6,11 +6,10 @@ git clone https://github.com/WebAssembly
 mv spec/interpreter/test/*.wast ./
 rm -rf spec/
 
 # TODO not handled yet
 rm -f *.fail.wast
 
 for i in $(ls *.wast);
 do
-    echo "// |jit-test| test-also-wasm-baseline" > $i.js
-    echo "var importedArgs = ['$i']; load(scriptdir + '../spec.js');" >> $i.js
+    echo "var importedArgs = ['$i']; load(scriptdir + '../spec.js');" > $i.js
 done;

--- a/js/src/jit-test/tests/wasm/spec/imports.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/imports.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['imports.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/int_exprs.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/int_exprs.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['int_exprs.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/int_literals.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/int_literals.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['int_literals.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/labels.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/labels.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['labels.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/left-to-right.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/left-to-right.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['left-to-right.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/linking.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/linking.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['linking.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/loop.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/loop.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['loop.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/memory.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/memory.wast.js
@@ -1,4 +1,3 @@
-// |jit-test| test-also-wasm-baseline
 // TODO initializer expression can reference global module-defined variables?
 quit();
 var importedArgs = ['memory.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/memory_redundancy.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/memory_redundancy.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['memory_redundancy.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/memory_trap.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/memory_trap.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['memory_trap.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/names.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/names.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['names.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/nop.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/nop.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['nop.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/resizing.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/resizing.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['resizing.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/return.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/return.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['return.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/select.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/select.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['select.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/set_local.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/set_local.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['set_local.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/skip-stack-guard-page.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/skip-stack-guard-page.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['skip-stack-guard-page.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/soft-fail.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/soft-fail.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['soft-fail.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/stack.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/stack.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['stack.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/start.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/start.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['start.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/store_retval.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/store_retval.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['store_retval.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/switch.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/switch.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['switch.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/tee_local.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/tee_local.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['tee_local.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/traps.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/traps.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['traps.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/typecheck.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/typecheck.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['typecheck.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/unreachable.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/unreachable.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['unreachable.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/spec/unwind.wast.js
+++ b/js/src/jit-test/tests/wasm/spec/unwind.wast.js
@@ -1,2 +1,1 @@
-// |jit-test| test-also-wasm-baseline
 var importedArgs = ['unwind.wast']; load(scriptdir + '../spec.js');

--- a/js/src/jit-test/tests/wasm/stack.js
+++ b/js/src/jit-test/tests/wasm/stack.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 // Test instructions with no return value interposed between pushes and pops.
 wasmFullPass(` (module
    (memory 1)
 
    (func (result i32)
      (local $local f64)

--- a/js/src/jit-test/tests/wasm/start.js
+++ b/js/src/jit-test/tests/wasm/start.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 assertErrorMessage(() => wasmEvalText('(module (func) (start 0) (start 0))'), SyntaxError, /wasm text error/);
 assertErrorMessage(() => wasmEvalText('(module (func) (start $unknown))'), SyntaxError, /label.*not found/);
 
 wasmFailValidateText('(module (func) (start 1))', /unknown start function/);
 wasmFailValidateText('(module (func (param i32)) (start 0))', /must be nullary/);
 wasmFailValidateText('(module (func (param i32) (param f32)) (start 0))', /must be nullary/);

--- a/js/src/jit-test/tests/wasm/tables.js
+++ b/js/src/jit-test/tests/wasm/tables.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + 'wasm.js');
 
 const Module = WebAssembly.Module;
 const Instance = WebAssembly.Instance;
 const Table = WebAssembly.Table;
 const Memory = WebAssembly.Memory;
 const RuntimeError = WebAssembly.RuntimeError;
 

--- a/js/src/jit-test/tests/wasm/text.js
+++ b/js/src/jit-test/tests/wasm/text.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 var parsingError = /parsing wasm text at/;
 
 assertErrorMessage(() => wasmEvalText(''), SyntaxError, parsingError);
 assertErrorMessage(() => wasmEvalText('('), SyntaxError, parsingError);
 assertErrorMessage(() => wasmEvalText('(m'), SyntaxError, parsingError);
 assertErrorMessage(() => wasmEvalText('(module'), SyntaxError, parsingError);

--- a/js/src/jit-test/tests/wasm/to-text-experimental.js
+++ b/js/src/jit-test/tests/wasm/to-text-experimental.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 assertErrorMessage(() => wasmBinaryToText(wasmTextToBinary(`(module (func (result i32) (f32.const 13.37)))`), 'experimental'), WebAssembly.CompileError, /type mismatch/);
 
 function runTest(code, expected) {
   var binary = wasmTextToBinary(code);
   var s = wasmBinaryToText(binary, "experimental");
   s = s.replace(/\s+/g, ' ');

--- a/js/src/jit-test/tests/wasm/to-text.js
+++ b/js/src/jit-test/tests/wasm/to-text.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 var caught = false;
 try {
     wasmBinaryToText(new Int8Array(1));
 } catch (e) {
     caught = true;
 }

--- a/js/src/jit-test/tests/wasm/unreachable.js
+++ b/js/src/jit-test/tests/wasm/unreachable.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 // In unreachable code, the current design is that validation is disabled,
 // meaning we have to have a special mode in the decoder for decoding code
 // that won't actually run.
 
 wasmFullPass(`(module
    (func (result i32)

--- a/js/src/jit-test/tests/wasm/validate.js
+++ b/js/src/jit-test/tests/wasm/validate.js
@@ -1,9 +1,8 @@
-// |jit-test| test-also-wasm-baseline
 load(libdir + "wasm.js");
 
 const { validate } = WebAssembly;
 
 assertErrorMessage(() => validate(), Error, /requires more than 0 arguments/);
 
 const argError = /first argument must be an ArrayBuffer or typed array object/;
 assertErrorMessage(() => validate(null), Error, argError);

--- a/js/src/jit/Ion.cpp
+++ b/js/src/jit/Ion.cpp
@@ -1899,16 +1899,18 @@ OptimizeMIR(MIRGenerator* mir)
 
     if (mir->compilingWasm()) {
         if (!EliminateBoundsChecks(mir, graph))
             return false;
         gs.spewPass("Redundant Bounds Check Elimination");
         AssertGraphCoherency(graph);
     }
 
+    DumpMIRExpressions(graph);
+
     return true;
 }
 
 LIRGraph*
 GenerateLIR(MIRGenerator* mir)
 {
     MIRGraph& graph = mir->graph();
     GraphSpewer& gs = mir->graphSpewer();

--- a/js/src/jit/IonAnalysis.cpp
+++ b/js/src/jit/IonAnalysis.cpp
@@ -4672,8 +4672,40 @@ jit::CreateMIRRootList(IonBuilder& build
             if (!iter->appendRoots(*roots))
                 return false;
         }
     }
 
     builder.setRootList(*roots);
     return true;
 }
+
+static void
+DumpDefinition(GenericPrinter& out, MDefinition* def, size_t depth)
+{
+    MDefinition::PrintOpcodeName(out, def->op());
+
+    if (depth == 0)
+        return;
+
+    for (size_t i = 0; i < def->numOperands(); i++) {
+        out.printf(" (");
+        DumpDefinition(out, def->getOperand(i), depth - 1);
+        out.printf(")");
+    }
+}
+
+void
+jit::DumpMIRExpressions(MIRGraph& graph)
+{
+    if (!JitSpewEnabled(JitSpew_MIRExpressions))
+        return;
+
+    size_t depth = 2;
+
+    Fprinter& out = JitSpewPrinter();
+    for (ReversePostorderIterator block(graph.rpoBegin()); block != graph.rpoEnd(); block++) {
+        for (MInstructionIterator iter(block->begin()), end(block->end()); iter != end; iter++) {
+            DumpDefinition(out, *iter, depth);
+            out.printf("\n");
+        }
+    }
+}

--- a/js/src/jit/IonAnalysis.h
+++ b/js/src/jit/IonAnalysis.h
@@ -191,12 +191,15 @@ MOZ_MUST_USE bool
 AnalyzeArgumentsUsage(JSContext* cx, JSScript* script);
 
 bool
 DeadIfUnused(const MDefinition* def);
 
 bool
 IsDiscardable(const MDefinition* def);
 
+void
+DumpMIRExpressions(MIRGraph& graph);
+
 } // namespace jit
 } // namespace js
 
 #endif /* jit_IonAnalysis_h */

--- a/js/src/jit/IonBuilder.cpp
+++ b/js/src/jit/IonBuilder.cpp
@@ -10389,21 +10389,25 @@ IonBuilder::setElemTryDense(bool* emitte
     // Don't generate a fast path if there have been bounds check failures
     // and this access might be on a sparse property.
     if (ElementAccessHasExtraIndexedProperty(this, object) && failedBoundsCheck_) {
         trackOptimizationOutcome(TrackedOutcome::ProtoIndexedProps);
         return true;
     }
 
     // Emit dense setelem variant.
-    if (!jsop_setelem_dense(conversion, object, index, value, unboxedType, writeHole))
-        return false;
+    if (!jsop_setelem_dense(conversion, object, index, value, unboxedType, writeHole, emitted))
+        return false;
+
+    if (!*emitted) {
+        trackOptimizationOutcome(TrackedOutcome::NonWritableProperty);
+        return true;
+    }
 
     trackOptimizationSuccess();
-    *emitted = true;
     return true;
 }
 
 bool
 IonBuilder::setElemTryArguments(bool* emitted, MDefinition* object,
                                 MDefinition* index, MDefinition* value)
 {
     MOZ_ASSERT(*emitted == false);
@@ -10475,29 +10479,40 @@ IonBuilder::setElemTryCache(bool* emitte
     trackOptimizationSuccess();
     *emitted = true;
     return true;
 }
 
 bool
 IonBuilder::jsop_setelem_dense(TemporaryTypeSet::DoubleConversion conversion,
                                MDefinition* obj, MDefinition* id, MDefinition* value,
-                               JSValueType unboxedType, bool writeHole)
-{
+                               JSValueType unboxedType, bool writeHole, bool* emitted)
+{
+    MOZ_ASSERT(*emitted == false);
+
     MIRType elementType = MIRType::None;
     if (unboxedType == JSVAL_TYPE_MAGIC)
         elementType = DenseNativeElementType(constraints(), obj);
     bool packed = ElementAccessIsPacked(constraints(), obj);
 
     // Writes which are on holes in the object do not have to bail out if they
     // cannot hit another indexed property on the object or its prototypes.
     bool hasNoExtraIndexedProperty = !ElementAccessHasExtraIndexedProperty(this, obj);
 
     bool mayBeFrozen = ElementAccessMightBeFrozen(constraints(), obj);
 
+    if (mayBeFrozen && !hasNoExtraIndexedProperty) {
+        // FallibleStoreElement does not know how to deal with extra indexed
+        // properties on the prototype. This case should be rare so we fall back
+        // to an IC.
+        return true;
+    }
+
+    *emitted = true;
+
     // Ensure id is an integer.
     MInstruction* idInt32 = MToInt32::New(alloc(), id);
     current->add(idInt32);
     id = idInt32;
 
     if (NeedsPostBarrier(value))
         current->add(MPostWriteElementBarrier::New(alloc(), obj, value, id));
 
@@ -10535,25 +10550,28 @@ IonBuilder::jsop_setelem_dense(Temporary
     }
 
     // Use MStoreElementHole if this SETELEM has written to out-of-bounds
     // indexes in the past. Otherwise, use MStoreElement so that we can hoist
     // the initialized length and bounds check.
     // If an object may have been frozen, no previous expectation hold and we
     // fallback to MFallibleStoreElement.
     MInstruction* store;
-    MStoreElementCommon *common = nullptr;
+    MStoreElementCommon* common = nullptr;
     if (writeHole && hasNoExtraIndexedProperty && !mayBeFrozen) {
         MStoreElementHole* ins = MStoreElementHole::New(alloc(), obj, elements, id, newValue, unboxedType);
         store = ins;
         common = ins;
 
         current->add(ins);
         current->push(value);
-    } else if (hasNoExtraIndexedProperty && mayBeFrozen) {
+    } else if (mayBeFrozen) {
+        MOZ_ASSERT(hasNoExtraIndexedProperty,
+                   "FallibleStoreElement codegen assumes no extra indexed properties");
+
         bool strict = IsStrictSetPC(pc);
         MFallibleStoreElement* ins = MFallibleStoreElement::New(alloc(), obj, elements, id,
                                                                 newValue, unboxedType, strict);
         store = ins;
         common = ins;
 
         current->add(ins);
         current->push(value);

--- a/js/src/jit/IonBuilder.h
+++ b/js/src/jit/IonBuilder.h
@@ -732,17 +732,17 @@ class IonBuilder
     MOZ_MUST_USE bool jsop_getelem_dense(MDefinition* obj, MDefinition* index,
                                          JSValueType unboxedType);
     MOZ_MUST_USE bool jsop_getelem_typed(MDefinition* obj, MDefinition* index,
                                          ScalarTypeDescr::Type arrayType);
     MOZ_MUST_USE bool jsop_setelem();
     MOZ_MUST_USE bool jsop_setelem_dense(TemporaryTypeSet::DoubleConversion conversion,
                                          MDefinition* object, MDefinition* index,
                                          MDefinition* value, JSValueType unboxedType,
-                                         bool writeHole);
+                                         bool writeHole, bool* emitted);
     MOZ_MUST_USE bool jsop_setelem_typed(ScalarTypeDescr::Type arrayType,
                                          MDefinition* object, MDefinition* index,
                                          MDefinition* value);
     MOZ_MUST_USE bool jsop_length();
     MOZ_MUST_USE bool jsop_length_fastPath();
     MOZ_MUST_USE bool jsop_arguments();
     MOZ_MUST_USE bool jsop_arguments_getelem();
     MOZ_MUST_USE bool jsop_runonce();

--- a/js/src/jit/JitSpewer.cpp
+++ b/js/src/jit/JitSpewer.cpp
@@ -410,56 +410,57 @@ jit::CheckLogging()
     if (!env)
         return;
     if (strstr(env, "help")) {
         fflush(nullptr);
         printf(
             "\n"
             "usage: IONFLAGS=option,option,option,... where options can be:\n"
             "\n"
-            "  aborts     Compilation abort messages\n"
-            "  scripts    Compiled scripts\n"
-            "  mir        MIR information\n"
-            "  prune      Prune unused branches\n"
-            "  escape     Escape analysis\n"
-            "  alias      Alias analysis\n"
-            "  alias-sum  Alias analysis: shows summaries for every block\n"
-            "  gvn        Global Value Numbering\n"
-            "  licm       Loop invariant code motion\n"
-            "  flac       Fold linear arithmetic constants\n"
-            "  eaa        Effective address analysis\n"
-            "  sincos     Replace sin/cos by sincos\n"
-            "  sink       Sink transformation\n"
-            "  regalloc   Register allocation\n"
-            "  inline     Inlining\n"
-            "  snapshots  Snapshot information\n"
-            "  codegen    Native code generation\n"
-            "  bailouts   Bailouts\n"
-            "  caches     Inline caches\n"
-            "  osi        Invalidation\n"
-            "  safepoints Safepoints\n"
-            "  pools      Literal Pools (ARM only for now)\n"
-            "  cacheflush Instruction Cache flushes (ARM only for now)\n"
-            "  range      Range Analysis\n"
-            "  unroll     Loop unrolling\n"
-            "  logs       C1 and JSON visualization logging\n"
-            "  logs-sync  Same as logs, but flushes between each pass (sync. compiled functions only).\n"
-            "  profiling  Profiling-related information\n"
-            "  trackopts  Optimization tracking information\n"
-            "  all        Everything\n"
+            "  aborts        Compilation abort messages\n"
+            "  scripts       Compiled scripts\n"
+            "  mir           MIR information\n"
+            "  prune         Prune unused branches\n"
+            "  escape        Escape analysis\n"
+            "  alias         Alias analysis\n"
+            "  alias-sum     Alias analysis: shows summaries for every block\n"
+            "  gvn           Global Value Numbering\n"
+            "  licm          Loop invariant code motion\n"
+            "  flac          Fold linear arithmetic constants\n"
+            "  eaa           Effective address analysis\n"
+            "  sincos        Replace sin/cos by sincos\n"
+            "  sink          Sink transformation\n"
+            "  regalloc      Register allocation\n"
+            "  inline        Inlining\n"
+            "  snapshots     Snapshot information\n"
+            "  codegen       Native code generation\n"
+            "  bailouts      Bailouts\n"
+            "  caches        Inline caches\n"
+            "  osi           Invalidation\n"
+            "  safepoints    Safepoints\n"
+            "  pools         Literal Pools (ARM only for now)\n"
+            "  cacheflush    Instruction Cache flushes (ARM only for now)\n"
+            "  range         Range Analysis\n"
+            "  unroll        Loop unrolling\n"
+            "  logs          C1 and JSON visualization logging\n"
+            "  logs-sync     Same as logs, but flushes between each pass (sync. compiled functions only).\n"
+            "  profiling     Profiling-related information\n"
+            "  trackopts     Optimization tracking information\n"
+            "  dump-mir-expr Dump the MIR expressions\n"
+            "  all           Everything\n"
             "\n"
-            "  bl-aborts  Baseline compiler abort messages\n"
-            "  bl-scripts Baseline script-compilation\n"
-            "  bl-op      Baseline compiler detailed op-specific messages\n"
-            "  bl-ic      Baseline inline-cache messages\n"
-            "  bl-ic-fb   Baseline IC fallback stub messages\n"
-            "  bl-osr     Baseline IC OSR messages\n"
-            "  bl-bails   Baseline bailouts\n"
-            "  bl-dbg-osr Baseline debug mode on stack recompile messages\n"
-            "  bl-all     All baseline spew\n"
+            "  bl-aborts     Baseline compiler abort messages\n"
+            "  bl-scripts    Baseline script-compilation\n"
+            "  bl-op         Baseline compiler detailed op-specific messages\n"
+            "  bl-ic         Baseline inline-cache messages\n"
+            "  bl-ic-fb      Baseline IC fallback stub messages\n"
+            "  bl-osr        Baseline IC OSR messages\n"
+            "  bl-bails      Baseline bailouts\n"
+            "  bl-dbg-osr    Baseline debug mode on stack recompile messages\n"
+            "  bl-all        All baseline spew\n"
             "\n"
         );
         exit(0);
         /*NOTREACHED*/
     }
     if (ContainsFlag(env, "aborts"))
         EnableChannel(JitSpew_IonAbort);
     if (ContainsFlag(env, "prune"))
@@ -513,16 +514,18 @@ jit::CheckLogging()
     if (ContainsFlag(env, "logs"))
         EnableIonDebugAsyncLogging();
     if (ContainsFlag(env, "logs-sync"))
         EnableIonDebugSyncLogging();
     if (ContainsFlag(env, "profiling"))
         EnableChannel(JitSpew_Profiling);
     if (ContainsFlag(env, "trackopts"))
         EnableChannel(JitSpew_OptimizationTracking);
+    if (ContainsFlag(env, "dump-mir-expr"))
+        EnableChannel(JitSpew_MIRExpressions);
     if (ContainsFlag(env, "all"))
         LoggingBits = uint64_t(-1);
 
     if (ContainsFlag(env, "bl-aborts"))
         EnableChannel(JitSpew_BaselineAbort);
     if (ContainsFlag(env, "bl-scripts"))
         EnableChannel(JitSpew_BaselineScripts);
     if (ContainsFlag(env, "bl-op"))

--- a/js/src/jit/JitSpewer.h
+++ b/js/src/jit/JitSpewer.h
@@ -59,16 +59,18 @@ namespace jit {
     /* Debug info about Pools*/             \
     _(Pools)                                \
     /* Profiling-related information */     \
     _(Profiling)                            \
     /* Information of tracked opt strats */ \
     _(OptimizationTracking)                 \
     /* Debug info about the I$ */           \
     _(CacheFlush)                           \
+    /* Output a list of MIR expressions */  \
+    _(MIRExpressions)                       \
                                             \
     /* BASELINE COMPILER SPEW */            \
                                             \
     /* Aborting Script Compilation. */      \
     _(BaselineAbort)                        \
     /* Script Compilation. */               \
     _(BaselineScripts)                      \
     /* Detailed op-specific spew. */        \

--- a/js/src/jit/LIR.cpp
+++ b/js/src/jit/LIR.cpp
@@ -343,46 +343,49 @@ LNode::printName(GenericPrinter& out)
 bool
 LAllocation::aliases(const LAllocation& other) const
 {
     if (isFloatReg() && other.isFloatReg())
         return toFloatReg()->reg().aliases(other.toFloatReg()->reg());
     return *this == other;
 }
 
-static const char * const TypeChars[] =
+static const char*
+typeName(LDefinition::Type type)
 {
-    "g",            // GENERAL
-    "i",            // INT32
-    "i64",          // INT64
-    "o",            // OBJECT
-    "s",            // SLOTS
-    "f",            // FLOAT32
-    "d",            // DOUBLE
-    "simd128int",   // SIMD128INT
-    "simd128float", // SIMD128FLOAT
-    "sincos",       // SINCOS
+    switch (type) {
+      case LDefinition::GENERAL: return "g";
+      case LDefinition::INT32: return "i";
+      case LDefinition::OBJECT: return "o";
+      case LDefinition::SLOTS: return "s";
+      case LDefinition::FLOAT32: return "f";
+      case LDefinition::DOUBLE: return "d";
+      case LDefinition::SIMD128INT: return "simd128int";
+      case LDefinition::SIMD128FLOAT: return "simd128float";
+      case LDefinition::SINCOS: return "sincos";
 #ifdef JS_NUNBOX32
-    "t",            // TYPE
-    "p"             // PAYLOAD
-#elif JS_PUNBOX64
-    "x"             // BOX
+      case LDefinition::TYPE: return "t";
+      case LDefinition::PAYLOAD: return "p";
+#else
+      case LDefinition::BOX: return "x";
 #endif
-};
+    }
+    MOZ_CRASH("Invalid type");
+}
 
 UniqueChars
 LDefinition::toString() const
 {
     AutoEnterOOMUnsafeRegion oomUnsafe;
 
     char* buf;
     if (isBogusTemp()) {
         buf = JS_smprintf("bogus");
     } else {
-        buf = JS_smprintf("v%u<%s>", virtualRegister(), TypeChars[type()]);
+        buf = JS_smprintf("v%u<%s>", virtualRegister(), typeName(type()));
         if (buf) {
             if (policy() == LDefinition::FIXED)
                 buf = JS_sprintf_append(buf, ":%s", output()->toString().get());
             else if (policy() == LDefinition::MUST_REUSE_INPUT)
                 buf = JS_sprintf_append(buf, ":tied(%u)", getReusedInput());
         }
     }
 
@@ -604,15 +607,15 @@ LMoveGroup::addAfter(LAllocation from, L
 
 void
 LMoveGroup::printOperands(GenericPrinter& out)
 {
     for (size_t i = 0; i < numMoves(); i++) {
         const LMove& move = getMove(i);
         out.printf(" [%s -> %s", move.from().toString().get(), move.to().toString().get());
 #ifdef DEBUG
-        out.printf(", %s", TypeChars[move.type()]);
+        out.printf(", %s", typeName(move.type()));
 #endif
         out.printf("]");
         if (i != numMoves() - 1)
             out.printf(",");
     }
 }