[compiler] Remove the special case "prototype" load in class literals.

src/compiler/ast-graph-builder.cc

 // Copyright 2014 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/compiler/ast-graph-builder.h"
 
 #include "src/ast/scopes.h"
 #include "src/compiler.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/control-builders.h"
@@ skipping 1564 matching lines @@
 
   // Create node to instantiate a new class.
   Node* constructor = environment()->Pop();
   Node* extends = environment()->Pop();
   Node* start = jsgraph()->Constant(expr->start_position());
   Node* end = jsgraph()->Constant(expr->end_position());
   const Operator* opc = javascript()->CallRuntime(Runtime::kDefineClass);
   Node* literal = NewNode(opc, extends, constructor, start, end);
   PrepareFrameState(literal, expr->CreateLiteralId(),
                     OutputFrameStateCombine::Push());
+  environment()->Push(literal);
 
-  // The prototype is ensured to exist by Runtime_DefineClass. No access check
-  // is needed here since the constructor is created by the class literal.
-  Node* prototype =
-      BuildLoadObjectField(literal, JSFunction::kPrototypeOrInitialMapOffset);
-
-  // The class literal and the prototype are both expected on the operand stack
-  // during evaluation of the method values.
-  environment()->Push(literal);
+  // Load the "prototype" from the constructor.
+  FrameStateBeforeAndAfter states(this, expr->CreateLiteralId());
+  Handle<Name> name = isolate()->factory()->prototype_string();
+  VectorSlotPair pair = CreateVectorSlotPair(expr->PrototypeSlot());
+  Node* prototype = BuildNamedLoad(literal, name, pair);
+  states.AddToNode(prototype, expr->PrototypeId(),
+                   OutputFrameStateCombine::Push());
   environment()->Push(prototype);
 
   // Create nodes to store method values into the literal.
   for (int i = 0; i < expr->properties()->length(); i++) {
     ObjectLiteral::Property* property = expr->properties()->at(i);
     environment()->Push(environment()->Peek(property->is_static() ? 1 : 0));
 
     VisitForValue(property->key());
     Node* name = BuildToName(environment()->Pop(), expr->GetIdForProperty(i));
     environment()->Push(name);
@@ skipping 2060 matching lines @@
 
 Node* AstGraphBuilder::BuildGlobalStore(Handle<Name> name, Node* value,
                                         const VectorSlotPair& feedback) {
   const Operator* op =
       javascript()->StoreGlobal(language_mode(), name, feedback);
   Node* node = NewNode(op, value, BuildLoadFeedbackVector());
   return node;
 }
 
 
-Node* AstGraphBuilder::BuildLoadObjectField(Node* object, int offset) {
-  return NewNode(jsgraph()->machine()->Load(MachineType::AnyTagged()), object,
-                 jsgraph()->IntPtrConstant(offset - kHeapObjectTag));
-}
-
-
 Node* AstGraphBuilder::BuildLoadImmutableObjectField(Node* object, int offset) {
   return graph()->NewNode(jsgraph()->machine()->Load(MachineType::AnyTagged()),
                           object,
                           jsgraph()->IntPtrConstant(offset - kHeapObjectTag),
                           graph()->start(), graph()->start());
 }
 
 
 Node* AstGraphBuilder::BuildLoadGlobalObject() {
   return BuildLoadNativeContextField(Context::EXTENSION_INDEX);
@@ skipping 671 matching lines @@
     // Phi does not exist yet, introduce one.
     value = NewPhi(inputs, value, control);
     value->ReplaceInput(inputs - 1, other);
   }
   return value;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8