Enable IonMonkey in the browser, and introduce an about:config option to pref it off (bug 745390, r=dmandelin).

dom/base/nsJSEnvironment.cpp

@@ -929,6 +929,7 @@ static const char js_pccounts_content_str[]   = JS_OPTIONS_DOT_STR "pccounts.con
 static const char js_pccounts_chrome_str[]    = JS_OPTIONS_DOT_STR "pccounts.chrome";
 static const char js_jit_hardening_str[]      = JS_OPTIONS_DOT_STR "jit_hardening";
 static const char js_memlog_option_str[] = JS_OPTIONS_DOT_STR "mem.log";
+static const char js_ion_content_str[]        = JS_OPTIONS_DOT_STR "ion.content";
 
 int
 nsJSContext::JSOptionChangedCallback(const char *pref, void *data)
@@ -964,6 +965,7 @@ nsJSContext::JSOptionChangedCallback(const char *pref, void *data)
   bool useMethodJITAlways = Preferences::GetBool(js_methodjit_always_str);
   bool useTypeInference = !chromeWindow && contentWindow && Preferences::GetBool(js_typeinfer_str);
   bool useHardening = Preferences::GetBool(js_jit_hardening_str);
+  bool useIon = Preferences::GetBool(js_ion_content_str);
   nsCOMPtr<nsIXULRuntime> xr = do_GetService(XULRUNTIME_SERVICE_CONTRACTID);
   if (xr) {
     bool safeMode = false;
@@ -974,6 +976,7 @@ nsJSContext::JSOptionChangedCallback(const char *pref, void *data)
       useTypeInference = false;
       useMethodJITAlways = true;
       useHardening = false;
+      useIon = false;
     }
   }    
 
@@ -997,6 +1000,11 @@ nsJSContext::JSOptionChangedCallback(const char *pref, void *data)
   else
     newDefaultJSOptions &= ~JSOPTION_TYPE_INFERENCE;
 
+  if (useIon)
+    newDefaultJSOptions |= JSOPTION_ION;
+  else
+    newDefaultJSOptions &= ~JSOPTION_ION;
+
 #ifdef DEBUG
   // In debug builds, warnings are enabled in chrome context if
   // javascript.options.strict.debug is true

dom/workers/RuntimeService.cpp

@@ -182,6 +182,7 @@ enum {
   PREF_typeinference,
   PREF_jit_hardening,
   PREF_mem_max,
+  PREF_ion,
 
 #ifdef JS_GC_ZEAL
   PREF_gczeal,
@@ -200,7 +201,8 @@ const char* gPrefsToWatch[] = {
   JS_OPTIONS_DOT_STR "methodjit_always",
   JS_OPTIONS_DOT_STR "typeinference",
   JS_OPTIONS_DOT_STR "jit_hardening",
-  JS_OPTIONS_DOT_STR "mem.max"
+  JS_OPTIONS_DOT_STR "mem.max",
+  JS_OPTIONS_DOT_STR "ion.content"
 
 #ifdef JS_GC_ZEAL
   , PREF_WORKERS_GCZEAL
@@ -247,6 +249,9 @@ PrefCallback(const char* aPrefName, void* aClosure)
     if (Preferences::GetBool(gPrefsToWatch[PREF_typeinference])) {
       newOptions |= JSOPTION_TYPE_INFERENCE;
     }
+    if (Preferences::GetBool(gPrefsToWatch[PREF_ion])) {
+      newOptions |= JSOPTION_ION;
+    }
 
     RuntimeService::SetDefaultJSContextOptions(newOptions);
     rts->UpdateAllWorkerJSContextOptions();

js/src/tests/browser.js

@@ -224,7 +224,8 @@ function optionsInit() {
     xml:        true,
     relimit:    true,
     methodjit:  true,
-    methodjit_always: true
+    methodjit_always: true,
+    ion:        true
   };
 
   // record initial values to support resetting

js/src/tests/shell.js

@@ -649,7 +649,8 @@ function optionsClear() {
     var optionName = optionNames[i];
     if (optionName &&
         optionName != "methodjit" &&
-        optionName != "methodjit_always")
+        optionName != "methodjit_always" &&
+        optionName != "ion")
     {
       options(optionName);
     }

js/src/tests/user.js

@@ -29,6 +29,7 @@ user_pref("extensions.checkUpdateSecurity", false);
 user_pref("browser.EULA.override", true);
 user_pref("javascript.options.methodjit.chrome", true);
 user_pref("javascript.options.methodjit.content", true);
+user_pref("javascript.options.ion.content", true);
 user_pref("javascript.options.methodjit_always", false);
 user_pref("javascript.options.strict", false);
 user_pref("javascript.options.werror", false);

js/xpconnect/idl/xpccomponents.idl

@@ -360,6 +360,9 @@ interface nsIXPCComponents_Utils : nsISupports
     [implicit_jscontext]
     attribute boolean methodjit_always;
 
+    [implicit_jscontext]
+    attribute boolean ion;
+
     [implicit_jscontext]
     void setGCZeal(in long zeal);
 };

js/xpconnect/src/XPCComponents.cpp

@@ -4022,6 +4022,7 @@ GENERATE_JSOPTION_GETTER_SETTER(Xml, JSOPTION_XML)
 GENERATE_JSOPTION_GETTER_SETTER(Relimit, JSOPTION_RELIMIT)
 GENERATE_JSOPTION_GETTER_SETTER(Methodjit, JSOPTION_METHODJIT)
 GENERATE_JSOPTION_GETTER_SETTER(Methodjit_always, JSOPTION_METHODJIT_ALWAYS)
+GENERATE_JSOPTION_GETTER_SETTER(Ion, JSOPTION_ION);
 
 #undef GENERATE_JSOPTION_GETTER_SETTER
 

modules/libpref/src/init/all.js

@@ -662,6 +662,7 @@ pref("javascript.options.strict.debug",     true);
 #endif
 pref("javascript.options.relimit",          true);
 pref("javascript.options.methodjit.content", true);
+pref("javascript.options.ion.content",      true);
 pref("javascript.options.methodjit.chrome",  true);
 pref("javascript.options.pccounts.content", false);
 pref("javascript.options.pccounts.chrome",  false);