Bug 1316098 - Optimize out result object allocation for await/return in async function.

Tag #1287

1 files changed, 5 insertions, 19 deletions

diff --git a/js/src/vm/AsyncFunction.cpp b/js/src/vm/AsyncFunction.cpp
index be7a36ecc..2bcec5465 100644
--- a/js/src/vm/AsyncFunction.cpp
+++ b/js/src/vm/AsyncFunction.cpp
@@ -171,22 +171,14 @@ AsyncFunctionResume(JSContext* cx, Handle<PromiseObject*> resultPromise, HandleV
                                  : cx->names().StarGeneratorThrow;
     FixedInvokeArgs<1> args(cx);
     args[0].set(valueOrReason);
-    RootedValue result(cx);
-    if (!CallSelfHostedFunction(cx, funName, generatorVal, args, &result))
-        return AsyncFunctionThrown(cx, resultPromise);
-
-    RootedObject resultObj(cx, &result.toObject());
-    RootedValue doneVal(cx);
     RootedValue value(cx);
-    if (!GetProperty(cx, resultObj, resultObj, cx->names().done, &doneVal))
-        return false;
-    if (!GetProperty(cx, resultObj, resultObj, cx->names().value, &value))
-        return false;
+    if (!CallSelfHostedFunction(cx, funName, generatorVal, args, &value))
+        return AsyncFunctionThrown(cx, resultPromise);
 
-    if (doneVal.toBoolean())
-        return AsyncFunctionReturned(cx, resultPromise, value);
+    if (generatorVal.toObject().as<GeneratorObject>().isAfterAwait())
+        return AsyncFunctionAwait(cx, resultPromise, value);
 
-    return AsyncFunctionAwait(cx, resultPromise, value);
+    return AsyncFunctionReturned(cx, resultPromise, value);
 }
 
 // Async Functions proposal 2.2 steps 3-8.
@@ -242,9 +234,3 @@ js::IsWrappedAsyncFunction(JSFunction* fun)
 {
     return fun->maybeNative() == WrappedAsyncFunction;
 }
-
-MOZ_MUST_USE bool
-js::CheckAsyncResumptionValue(JSContext* cx, HandleValue v)
-{
-    return CheckStarGeneratorResumptionValue(cx, v);
-}