[Interpreter] Add SetPendingMessage bytecode.

src/interpreter/interpreter.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/interpreter/interpreter.h"
 
 #include <fstream>
 #include <memory>
 
 #include "src/ast/prettyprinter.h"
@@ skipping 2353 matching lines @@
   __ Dispatch();
 
   __ Bind(&stack_check_interrupt);
   {
     Node* context = __ GetContext();
     __ CallRuntime(Runtime::kStackGuard, context);
     __ Dispatch();
   }
 }
 
+// SetPendingMessage
+//
+// Sets the pending message to the value in the accumulator, and returns the
+// previous pending message in the accumulator.
+void Interpreter::DoSetPendingMessage(InterpreterAssembler* assembler) {
+  Node* pending_message = __ ExternalConstant(
+      ExternalReference::address_of_pending_message_obj(isolate_));
+  Node* previous_message =
+      __ Load(MachineType::TaggedPointer(), pending_message);
+  Node* new_message = __ GetAccumulator();
+  __ StoreNoWriteBarrier(MachineRepresentation::kTaggedPointer, pending_message,
+                         new_message);
+  __ SetAccumulator(previous_message);
+  __ Dispatch();
+}
+
 // Throw
 //
 // Throws the exception in the accumulator.
 void Interpreter::DoThrow(InterpreterAssembler* assembler) {
   Node* exception = __ GetAccumulator();
   Node* context = __ GetContext();
   __ CallRuntime(Runtime::kThrow, context, exception);
   // We shouldn't ever return from a throw.
   __ Abort(kUnexpectedReturnFromThrow);
 }
@@ skipping 299 matching lines @@
   __ StoreObjectField(generator, JSGeneratorObject::kContinuationOffset,
       __ SmiTag(new_state));
   __ SetAccumulator(old_state);
 
   __ Dispatch();
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8