Reland deprecation of HAllocateObject in favor of HAllocate.

src/hydrogen.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 7239 matching lines @@
 
   call->set_position(expr->position());
   return ast_context()->ReturnInstruction(call, expr->id());
 }
 
 
 // Checks whether allocation using the given constructor can be inlined.
 static bool IsAllocationInlineable(Handle<JSFunction> constructor) {
   return constructor->has_initial_map() &&
       constructor->initial_map()->instance_type() == JS_OBJECT_TYPE &&
-      constructor->initial_map()->instance_size() < HAllocateObject::kMaxSize;
+      constructor->initial_map()->instance_size() < HAllocate::kMaxInlineSize &&
+      constructor->initial_map()->InitialPropertiesLength() == 0;
 }
 
 
 void HOptimizedGraphBuilder::VisitCallNew(CallNew* expr) {
   ASSERT(!HasStackOverflow());
   ASSERT(current_block() != NULL);
   ASSERT(current_block()->HasPredecessor());
   int argument_count = expr->arguments()->length() + 1;  // Plus constructor.
   HValue* context = environment()->LookupContext();
+  Factory* factory = isolate()->factory();
 
   if (FLAG_inline_construct &&
       expr->IsMonomorphic() &&
       IsAllocationInlineable(expr->target())) {
     // The constructor function is on the stack in the unoptimized code
     // during evaluation of the arguments.
     CHECK_ALIVE(VisitForValue(expr->expression()));
     HValue* function = Top();
     CHECK_ALIVE(VisitExpressions(expr->arguments()));
     Handle<JSFunction> constructor = expr->target();
     HValue* check = Add<HCheckFunction>(function, constructor);
 
     // Force completion of inobject slack tracking before generating
     // allocation code to finalize instance size.
     if (constructor->shared()->IsInobjectSlackTrackingInProgress()) {
       constructor->shared()->CompleteInobjectSlackTracking();
     }
 
-    // Replace the constructor function with a newly allocated receiver.
-    HInstruction* receiver = Add<HAllocateObject>(context, constructor);
-    // Index of the receiver from the top of the expression stack.
+    // Calculate instance size from initial map of constructor.
+    ASSERT(constructor->has_initial_map());
+    Handle<Map> initial_map(constructor->initial_map());
+    int instance_size = initial_map->instance_size();
+    ASSERT(initial_map->InitialPropertiesLength() == 0);
+
+    // Allocate an instance of the implicit receiver object.
+    HValue* size_in_bytes = Add<HConstant>(instance_size);
+    HAllocate::Flags flags = HAllocate::DefaultFlags();
+    if (FLAG_pretenuring_call_new &&
+        isolate()->heap()->ShouldGloballyPretenure()) {
+      flags = static_cast<HAllocate::Flags>(
+          flags | HAllocate::CAN_ALLOCATE_IN_OLD_POINTER_SPACE);
+    }
+    HAllocate* receiver =
+        Add<HAllocate>(context, size_in_bytes, HType::JSObject(), flags);
+    receiver->set_known_initial_map(initial_map);
+
+    // Load the initial map from the constructor.
+    HValue* constructor_value = Add<HConstant>(constructor);
+    HValue* initial_map_value =
+        AddLoad(constructor_value, HObjectAccess::ForJSObjectOffset(
+            JSFunction::kPrototypeOrInitialMapOffset));
+
+    // Initialize map and fields of the newly allocated object.
+    { NoObservableSideEffectsScope no_effects(this);
+      ASSERT(initial_map->instance_type() == JS_OBJECT_TYPE);
+      AddStore(receiver,
+               HObjectAccess::ForJSObjectOffset(JSObject::kMapOffset),
+               initial_map_value);
+      HValue* empty_fixed_array = Add<HConstant>(factory->empty_fixed_array());
+      AddStore(receiver,
+               HObjectAccess::ForJSObjectOffset(JSObject::kPropertiesOffset),
+               empty_fixed_array);
+      AddStore(receiver,
+               HObjectAccess::ForJSObjectOffset(JSObject::kElementsOffset),
+               empty_fixed_array);
+      if (initial_map->inobject_properties() != 0) {
+        HConstant* undefined = graph()->GetConstantUndefined();
+        for (int i = 0; i < initial_map->inobject_properties(); i++) {
+          int property_offset = JSObject::kHeaderSize + i * kPointerSize;
+          AddStore(receiver,
+                   HObjectAccess::ForJSObjectOffset(property_offset),
+                   undefined);
+        }
+      }
+    }
+
+    // Replace the constructor function with a newly allocated receiver using
+    // the index of the receiver from the top of the expression stack.
     const int receiver_index = argument_count - 1;
     ASSERT(environment()->ExpressionStackAt(receiver_index) == function);
     environment()->SetExpressionStackAt(receiver_index, receiver);
 
     if (TryInlineConstruct(expr, receiver)) return;
 
-    // TODO(mstarzinger): For now we remove the previous HAllocateObject and
-    // add HPushArgument for the arguments in case inlining failed.  What we
-    // actually should do is emit HInvokeFunction on the constructor instead
-    // of using HCallNew as a fallback.
+    // TODO(mstarzinger): For now we remove the previous HAllocate and all
+    // corresponding instructions and instead add HPushArgument for the
+    // arguments in case inlining failed.  What we actually should do is for
+    // inlining to try to build a subgraph without mutating the parent graph.
+    HInstruction* instr = current_block()->last();
+    while (instr != initial_map_value) {
+      HInstruction* prev_instr = instr->previous();
+      instr->DeleteAndReplaceWith(NULL);
+      instr = prev_instr;
+    }
+    initial_map_value->DeleteAndReplaceWith(NULL);
     receiver->DeleteAndReplaceWith(NULL);
     check->DeleteAndReplaceWith(NULL);
     environment()->SetExpressionStackAt(receiver_index, function);
     HInstruction* call = PreProcessCall(
         new(zone()) HCallNew(context, function, argument_count));
     call->set_position(expr->position());
     return ast_context()->ReturnInstruction(call, expr->id());
   } else {
     // The constructor function is both an operand to the instruction and an
     // argument to the construct call.
@@ skipping 2640 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal