Reduce microtask count in import(path) (expressions)

oven-sh · Sep 15, 2024 · 8a5ce39 · 8a5ce39
1 parent 20e270d
commit 8a5ce39
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Showing 5 changed files with 28 additions and 5 deletions.
diff --git a/Source/JavaScriptCore/runtime/JSGlobalObjectFunctions.cpp b/Source/JavaScriptCore/runtime/JSGlobalObjectFunctions.cpp
@@ -845,23 +845,25 @@ JSC_DEFINE_HOST_FUNCTION(globalFuncImportMapStatus, (JSGlobalObject* globalObjec
 JSC_DEFINE_HOST_FUNCTION(globalFuncImportModule, (JSGlobalObject* globalObject, CallFrame* callFrame))
 {
     VM& vm = globalObject->vm();
-
-    auto* promise = JSPromise::create(vm, globalObject->promiseStructure());
-
     auto scope = DECLARE_THROW_SCOPE(vm);
 
     auto sourceOrigin = callFrame->callerSourceOrigin(vm);
     RELEASE_ASSERT(callFrame->argumentCount() >= 1);
     auto* specifier = callFrame->uncheckedArgument(0).toString(globalObject);
-    RETURN_IF_EXCEPTION(scope, JSValue::encode(promise->rejectWithCaughtException(globalObject, scope)));
+    RETURN_IF_EXCEPTION(scope, JSValue::encode(JSPromise::rejectedPromiseWithCaughtException(globalObject, scope)));
 
     // We always specify parameters as undefined. Once dynamic import() starts accepting fetching parameters,
     // we should retrieve this from the arguments.
     JSValue parameters = callFrame->argument(1);
     auto* internalPromise = globalObject->moduleLoader()->importModule(globalObject, specifier, parameters, sourceOrigin);
-    RETURN_IF_EXCEPTION(scope, JSValue::encode(promise->rejectWithCaughtException(globalObject, scope)));
+    RETURN_IF_EXCEPTION(scope, JSValue::encode(JSPromise::rejectedPromiseWithCaughtException(globalObject, scope)));
 
     scope.release();
+    if (internalPromise->status(vm) == JSPromise::Status::Fulfilled) {
+        return JSPromise::resolvedPromise(globalObject, internalPromise->result(vm));
+    }
+
+    auto* promise = JSPromise::create(vm, globalObject->promiseStructure());    
     promise->resolve(globalObject, internalPromise);
     return JSValue::encode(promise);
 }

diff --git a/Source/JavaScriptCore/runtime/JSInternalPromise.cpp b/Source/JavaScriptCore/runtime/JSInternalPromise.cpp
@@ -79,4 +79,9 @@ JSInternalPromise* JSInternalPromise::rejectWithCaughtException(JSGlobalObject*
     return jsCast<JSInternalPromise*>(JSPromise::rejectWithCaughtException(globalObject, scope));
 }
 
+JSInternalPromise* JSInternalPromise::rejectedPromiseWithCaughtException(JSGlobalObject* globalObject, ThrowScope& scope)
+{
+    return jsCast<JSInternalPromise*>(JSPromise::rejectedPromiseWithCaughtException(globalObject, scope));
+}
+
 } // namespace JSC
diff --git a/Source/JavaScriptCore/runtime/JSInternalPromise.h b/Source/JavaScriptCore/runtime/JSInternalPromise.h
@@ -52,6 +52,7 @@ class JSInternalPromise final : public JSPromise {
     JS_EXPORT_PRIVATE JSInternalPromise* then(JSGlobalObject*, JSFunction* = nullptr, JSFunction* = nullptr);
 
     JS_EXPORT_PRIVATE JSInternalPromise* rejectWithCaughtException(JSGlobalObject*, ThrowScope&);
+    JS_EXPORT_PRIVATE static JSInternalPromise* rejectedPromiseWithCaughtException(JSGlobalObject*, ThrowScope&);
 
 private:
     JSInternalPromise(VM&, Structure*);

diff --git a/Source/JavaScriptCore/runtime/JSPromise.cpp b/Source/JavaScriptCore/runtime/JSPromise.cpp
@@ -260,6 +260,20 @@ JSPromise* JSPromise::rejectWithCaughtException(JSGlobalObject* globalObject, Th
     return this;
 }
 
+JSPromise* JSPromise::rejectedPromiseWithCaughtException(JSGlobalObject* globalObject, ThrowScope& scope)
+{
+    VM& vm = globalObject->vm();
+    Exception* exception = scope.exception();
+    ASSERT(exception);
+    if (UNLIKELY(vm.isTerminationException(exception))) {
+        scope.release();
+        return nullptr;
+    }
+    scope.clearException();
+    scope.release();
+    return rejectedPromise(globalObject, exception->value());
+}
+
 void JSPromise::performPromiseThen(JSGlobalObject* globalObject, JSFunction* onFulFilled, JSFunction* onRejected, JSValue resultCapability)
 {
     JSFunction* performPromiseThenFunction = globalObject->performPromiseThenFunction();

diff --git a/Source/JavaScriptCore/runtime/JSPromise.h b/Source/JavaScriptCore/runtime/JSPromise.h
@@ -78,6 +78,7 @@ class JSPromise : public JSInternalFieldObjectImpl<2> {
 
     JS_EXPORT_PRIVATE static JSPromise* resolvedPromise(JSGlobalObject*, JSValue);
     JS_EXPORT_PRIVATE static JSPromise* rejectedPromise(JSGlobalObject*, JSValue);
+    JS_EXPORT_PRIVATE static JSPromise* rejectedPromiseWithCaughtException(JSGlobalObject*, ThrowScope&);
 
     JS_EXPORT_PRIVATE void resolve(JSGlobalObject*, JSValue);
     JS_EXPORT_PRIVATE void reject(JSGlobalObject*, JSValue);