Bug 900669 - OdinMonkey: factor LinkAsmJS in preparation for later changes (r=bbouvier)

js/src/ion/AsmJSLink.cpp

@@ -552,27 +552,9 @@ SendBlocksToPerf(JSContext *cx, AsmJSModule &module)
 }
 #endif
 
-// Implements the semantics of an asm.js module function that has been successfully validated.
-// A successfully validated asm.js module does not have bytecode emitted, but rather a list of
-// dynamic constraints that must be satisfied by the arguments passed by the caller. If these
-// constraints are satisfied, then LinkAsmJS can return CallAsmJS native functions that trampoline
-// into compiled code. If any of the constraints fails, LinkAsmJS reparses the entire asm.js module
-// from source so that it can be run as plain bytecode.
 static bool
-LinkAsmJS(JSContext *cx, unsigned argc, JS::Value *vp)
+SendModuleToAttachedProfiler(JSContext *cx, AsmJSModule &module)
 {
-    CallArgs args = CallArgsFromVp(argc, vp);
-    RootedFunction fun(cx, &args.callee().as<JSFunction>());
-    RootedObject moduleObj(cx,  &fun->getExtendedSlot(MODULE_FUN_SLOT).toObject());
-    AsmJSModule &module = AsmJSModuleObjectToModule(moduleObj);
-
-    // If linking fails, recompile the function (including emitting bytecode)
-    // as if it's normal JS code.
-    if (!DynamicallyLinkModule(cx, args, module)) {
-        RootedPropertyName name(cx, fun->name());
-        return HandleDynamicLinkFailure(cx, args, module, name);
-    }
-
 #if defined(MOZ_VTUNE)
     if (IsVTuneProfilingActive() && !SendFunctionsToVTune(cx, module))
         return false;
@@ -585,37 +567,77 @@ LinkAsmJS(JSContext *cx, unsigned argc, JS::Value *vp)
         return false;
 #endif
 
+    return true;
+}
+
+
+static JSObject *
+CreateExportObject(JSContext *cx, HandleObject moduleObj)
+{
+    AsmJSModule &module = AsmJSModuleObjectToModule(moduleObj);
+
     if (module.numExportedFunctions() == 1) {
         const AsmJSModule::ExportedFunction &func = module.exportedFunction(0);
-        if (!func.maybeFieldName()) {
-            RootedFunction fun(cx, NewExportedFunction(cx, func, moduleObj, 0));
-            if (!fun)
-                return false;
-
-            args.rval().set(ObjectValue(*fun));
-            return true;
-        }
+        if (!func.maybeFieldName())
+            return NewExportedFunction(cx, func, moduleObj, 0);
     }
 
     gc::AllocKind allocKind = gc::GetGCObjectKind(module.numExportedFunctions());
     RootedObject obj(cx, NewBuiltinClassInstance(cx, &JSObject::class_, allocKind));
     if (!obj)
-        return false;
+        return NULL;
 
     for (unsigned i = 0; i < module.numExportedFunctions(); i++) {
         const AsmJSModule::ExportedFunction &func = module.exportedFunction(i);
 
         RootedFunction fun(cx, NewExportedFunction(cx, func, moduleObj, i));
         if (!fun)
-            return false;
+            return NULL;
 
         JS_ASSERT(func.maybeFieldName() != NULL);
         RootedId id(cx, NameToId(func.maybeFieldName()));
         RootedValue val(cx, ObjectValue(*fun));
         if (!DefineNativeProperty(cx, obj, id, val, NULL, NULL, JSPROP_ENUMERATE, 0, 0))
-            return false;
+            return NULL;
     }
 
+    return obj;
+}
+
+// Implements the semantics of an asm.js module function that has been successfully validated.
+static bool
+LinkAsmJS(JSContext *cx, unsigned argc, JS::Value *vp)
+{
+    CallArgs args = CallArgsFromVp(argc, vp);
+
+    // The LinkAsmJS builtin (created by NewAsmJSModuleFunction) is an extended
+    // function and stores its module in an extended slot.
+    RootedFunction fun(cx, &args.callee().as<JSFunction>());
+    RootedObject moduleObj(cx,  &fun->getExtendedSlot(MODULE_FUN_SLOT).toObject());
+    AsmJSModule &module = AsmJSModuleObjectToModule(moduleObj);
+
+    // Link the module by performing the link-time validation checks in the
+    // asm.js spec and then patching the generated module to associate it with
+    // the given heap (ArrayBuffer) and a new global data segment (the closure
+    // state shared by the inner asm.js functions).
+    if (!DynamicallyLinkModule(cx, args, module)) {
+        // Linking failed, so reparse the entire asm.js module from scratch to
+        // get normal interpreted bytecode which we can simply Invoke. Very slow.
+        RootedPropertyName name(cx, fun->name());
+        return HandleDynamicLinkFailure(cx, args, module, name);
+    }
+
+    // Notify profilers so that asm.js generated code shows up with JS function
+    // names and lines in native (i.e., not SPS) profilers.
+    if (!SendModuleToAttachedProfiler(cx, module))
+        return false;
+
+    // Link-time validation succeeded, so wrap all the exported functions with
+    // CallAsmJS builtins that trampoline into the generated code.
+    JSObject *obj = CreateExportObject(cx, moduleObj);
+    if (!obj)
+        return false;
+
     args.rval().set(ObjectValue(*obj));
     return true;
 }