[async-await] don't eagerly resolve Promise before finally blocks have executed

src/interpreter/bytecode-generator.cc

Index: src/interpreter/bytecode-generator.cc
diff --git a/src/interpreter/bytecode-generator.cc b/src/interpreter/bytecode-generator.cc
index 94ea80a18b6df5e3c000c581da9adc6a251f43b8..f87416e4d3709b4932d25c1d809f62daa520d826 100644
--- a/src/interpreter/bytecode-generator.cc
+++ b/src/interpreter/bytecode-generator.cc
@@ -2170,6 +2170,26 @@ void BytecodeGenerator::BuildVariableLoadForAccumulatorValue(
 }
 
 void BytecodeGenerator::BuildReturn() {
+  if (IsAsyncFunction(info()->literal()->kind())) {
+    RegisterAllocationScope register_scope(this);
+    RegisterList args = register_allocator()->NewRegisterList(3);
+    Register receiver = args[0];
+    Register promise = args[1];
+    Register return_value = args[2];
+    builder()->StoreAccumulatorInRegister(return_value);
+
+    Variable* var_promise = scope()->promise_var();
+    DCHECK_NOT_NULL(var_promise);
+    BuildVariableLoad(var_promise, FeedbackVectorSlot::Invalid(),
+                      HoleCheckMode::kElided);
+    builder()
+        ->StoreAccumulatorInRegister(promise)
+        .LoadUndefined()
+        .StoreAccumulatorInRegister(receiver)
+        .CallJSRuntime(Context::PROMISE_RESOLVE_INDEX, args)
+        .LoadAccumulatorWithRegister(promise);
+  }
+
   if (FLAG_trace) {
     RegisterAllocationScope register_scope(this);
     Register result = register_allocator()->NewRegister();