[promises] Refactor CreatePromise

src/code-stub-assembler.cc

Index: src/code-stub-assembler.cc
diff --git a/src/code-stub-assembler.cc b/src/code-stub-assembler.cc
index c6d79716a57a827279d3700c7c26e6ea72e8cafa..11568bf29b8f7a22c02b60af568d12fcee9f2975 100644
--- a/src/code-stub-assembler.cc
+++ b/src/code-stub-assembler.cc
@@ -8245,5 +8245,29 @@ Node* CodeStubAssembler::IsPromiseHookEnabled() {
   return WordNotEqual(is_promisehook_enabled, Int32Constant(0));
 }
 
+Node* CodeStubAssembler::AllocateJSPromise(Node* context) {
+  Node* const native_context = LoadNativeContext(context);
+  Node* const promise_fun =
+      LoadContextElement(native_context, Context::PROMISE_FUNCTION_INDEX);
+  Node* const initial_map =
+      LoadObjectField(promise_fun, JSFunction::kPrototypeOrInitialMapOffset);
+  Node* const instance = AllocateJSObjectFromMap(initial_map);
+
+  return instance;
+}
+
+void CodeStubAssembler::PromiseInit(Node* promise) {
+  StoreObjectField(promise, JSPromise::kStatusOffset,
+                   SmiConstant(kPromisePending));
+  StoreObjectField(promise, JSPromise::kFlagsOffset, SmiConstant(0));
+}
+
+void CodeStubAssembler::PromiseSet(Node* promise, Node* status, Node* result) {
+  CSA_ASSERT(this, TaggedIsSmi(status));
+  StoreObjectField(promise, JSPromise::kStatusOffset, status);
+  StoreObjectField(promise, JSPromise::kResultOffset, result);
+  StoreObjectField(promise, JSPromise::kFlagsOffset, SmiConstant(0));
+}
+
 }  // namespace internal
 }  // namespace v8