Bug 1842773 - Part 1: Add prefs for resizable ArrayBuffers and growable SharedArrayBuffers. r=sfink

There's intentionally only a single shell option which controls both options.
This makes testing easier and the test262 tests are also using a single
feature flag for resizable ArrayBuffers and growable SharedArrayBuffers.

Differential Revision: https://phabricator.services.mozilla.com/D183317

js/public/RealmOptions.h

@@ -246,6 +246,20 @@ class JS_PUBLIC_API RealmCreationOptions {
     symbolsAsWeakMapKeys_ = flag;
     return *this;
   }
+
+  bool getArrayBufferResizableEnabled() const { return arrayBufferResizable_; }
+  RealmCreationOptions& setArrayBufferResizableEnabled(bool flag) {
+    arrayBufferResizable_ = flag;
+    return *this;
+  }
+
+  bool getSharedArrayBufferGrowableEnabled() const {
+    return sharedArrayBufferGrowable_;
+  }
+  RealmCreationOptions& setSharedArrayBufferGrowableEnabled(bool flag) {
+    sharedArrayBufferGrowable_ = flag;
+    return *this;
+  }
 #endif
 
   // This flag doesn't affect JS engine behavior.  It is used by Gecko to
@@ -319,6 +333,10 @@ class JS_PUBLIC_API RealmCreationOptions {
   // Pref for new Set.prototype methods.
   bool newSetMethods_ = false;
   bool symbolsAsWeakMapKeys_ = false;
+  // Pref for resizable ArrayBuffers.
+  bool arrayBufferResizable_ = false;
+  // Pref for growable SharedArrayBuffers.
+  bool sharedArrayBufferGrowable_ = false;
 #endif
 
   // Pref for ArrayBuffer.prototype.transfer{,ToFixedLength}() methods.

js/src/shell/js.cpp

@@ -747,6 +747,8 @@ bool shell::enableArrayGrouping = false;
 bool shell::enableNewSetMethods = false;
 // Pref for ArrayBuffer.prototype.transfer{,ToFixedLength}() methods.
 bool shell::enableSymbolsAsWeakMapKeys = false;
+// Pref for resizable ArrayBuffers and growable SharedArrayBuffers.
+bool shell::enableArrayBufferResizable = false;
 #endif
 bool shell::enableArrayBufferTransfer = true;
 bool shell::enableImportAttributes = false;
@@ -4142,6 +4144,8 @@ static void SetStandardRealmOptions(JS::RealmOptions& options) {
 #ifdef NIGHTLY_BUILD
       .setNewSetMethodsEnabled(enableNewSetMethods)
       .setSymbolsAsWeakMapKeysEnabled(enableSymbolsAsWeakMapKeys)
+      .setArrayBufferResizableEnabled(enableArrayBufferResizable)
+      .setSharedArrayBufferGrowableEnabled(enableArrayBufferResizable)
 #endif
       ;
 }
@@ -11707,6 +11711,9 @@ bool InitOptionParser(OptionParser& op) {
                         "Disable ArrayBuffer.prototype.transfer() methods") ||
       !op.addBoolOption('\0', "enable-symbols-as-weakmap-keys",
                         "Enable Symbols As WeakMap keys") ||
+      !op.addBoolOption(
+          '\0', "enable-arraybuffer-resizable",
+          "Enable resizable ArrayBuffers and growable SharedArrayBuffers") ||
       !op.addBoolOption('\0', "enable-top-level-await",
                         "Enable top-level await") ||
       !op.addBoolOption('\0', "enable-class-static-blocks",
@@ -12236,6 +12243,7 @@ bool SetContextOptions(JSContext* cx, const OptionParser& op) {
   enableNewSetMethods = op.getBoolOption("enable-new-set-methods");
   enableSymbolsAsWeakMapKeys =
       op.getBoolOption("enable-symbols-as-weakmap-keys");
+  enableArrayBufferResizable = op.getBoolOption("enable-arraybuffer-resizable");
 #endif
   enableArrayBufferTransfer = !op.getBoolOption("disable-arraybuffer-transfer");
   enableImportAttributesAssertSyntax =

js/src/shell/jsshell.h

@@ -130,6 +130,7 @@ extern bool enableShadowRealms;
 extern bool enableArrayGrouping;
 extern bool enableWellFormedUnicodeStrings;
 extern bool enableArrayBufferTransfer;
+extern bool enableArrayBufferResizable;
 extern bool enableSymbolsAsWeakMapKeys;
 extern bool enableNewSetMethods;
 extern bool enableImportAttributes;

js/xpconnect/src/XPCJSContext.cpp

@@ -787,6 +787,8 @@ static mozilla::Atomic<bool> sArrayGroupingEnabled(false);
 #ifdef NIGHTLY_BUILD
 static mozilla::Atomic<bool> sNewSetMethodsEnabled(false);
 static mozilla::Atomic<bool> sSymbolsAsWeakMapKeysEnabled(false);
+static mozilla::Atomic<bool> sArrayBufferResizableEnabled(false);
+static mozilla::Atomic<bool> sSharedArrayBufferGrowableEnabled(false);
 #endif
 static mozilla::Atomic<bool> sArrayBufferTransferEnabled(false);
 
@@ -818,6 +820,8 @@ void xpc::SetPrefableRealmOptions(JS::RealmOptions& options) {
 #ifdef NIGHTLY_BUILD
       .setNewSetMethodsEnabled(sNewSetMethodsEnabled)
       .setSymbolsAsWeakMapKeysEnabled(sSymbolsAsWeakMapKeysEnabled)
+      .setArrayBufferResizableEnabled(sArrayBufferResizableEnabled)
+      .setSharedArrayBufferGrowableEnabled(sSharedArrayBufferGrowableEnabled)
 #endif
       ;
 }
@@ -1025,6 +1029,10 @@ static void ReloadPrefsCallback(const char* pref, void* aXpccx) {
       Preferences::GetBool(JS_OPTIONS_DOT_STR "experimental.new_set_methods");
   sSymbolsAsWeakMapKeysEnabled = Preferences::GetBool(
       JS_OPTIONS_DOT_STR "experimental.symbols_as_weakmap_keys");
+  sArrayBufferResizableEnabled = Preferences::GetBool(
+      JS_OPTIONS_DOT_STR "experimental.arraybuffer_resizable");
+  sSharedArrayBufferGrowableEnabled = Preferences::GetBool(
+      JS_OPTIONS_DOT_STR "experimental.sharedarraybuffer_growable");
 #endif
   sArrayBufferTransferEnabled =
       Preferences::GetBool(JS_OPTIONS_DOT_STR "arraybuffer_transfer");

modules/libpref/init/StaticPrefList.yaml

@@ -7479,6 +7479,18 @@
     type: bool
     value: false
     mirror: always
+
+  # Experimental support for resizable ArrayBuffers in JavaScript.
+-   name: javascript.options.experimental.arraybuffer_resizable
+    type: bool
+    value: false
+    mirror: always
+
+  # Experimental support for growable SharedArrayBuffers in JavaScript.
+-   name: javascript.options.experimental.sharedarraybuffer_growable
+    type: bool
+    value: false
+    mirror: always
 #endif  // NIGHTLY_BUILD
 
 # Experimental support for ArrayBuffer.prototype.transfer{,ToFixedLength}() in JavaScript.