[turbofan] Initial version of allocation folding and write barrier elimination.

src/compiler/js-create-lowering.cc

 // Copyright 2016 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/js-create-lowering.h"
 
 #include "src/allocation-site-scopes.h"
 #include "src/code-factory.h"
 #include "src/compilation-dependencies.h"
 #include "src/compiler/access-builder.h"
@@ skipping 935 matching lines @@
                                        isolate());
       if (boilerplate_value->IsJSObject()) {
         Handle<JSObject> boilerplate_object =
             Handle<JSObject>::cast(boilerplate_value);
         Handle<AllocationSite> current_site = site_context->EnterNewScope();
         value = effect = AllocateFastLiteral(effect, control,
                                              boilerplate_object, site_context);
         site_context->ExitScope(current_site, boilerplate_object);
       } else if (property_details.representation().IsDouble()) {
         // Allocate a mutable HeapNumber box and store the value into it.
-        value = effect = AllocateMutableHeapNumber(
-            Handle<HeapNumber>::cast(boilerplate_value)->value(),
+        effect = graph()->NewNode(common()->BeginRegion(), effect);
+        value = effect = graph()->NewNode(
+            simplified()->Allocate(NOT_TENURED),
+            jsgraph()->Constant(HeapNumber::kSize), effect, control);
+        effect = graph()->NewNode(
+            simplified()->StoreField(AccessBuilder::ForMap()), value,
+            jsgraph()->HeapConstant(factory()->mutable_heap_number_map()),
             effect, control);
+        effect = graph()->NewNode(
+            simplified()->StoreField(AccessBuilder::ForHeapNumberValue()),
+            value, jsgraph()->Constant(
+                       Handle<HeapNumber>::cast(boilerplate_value)->value()),
+            effect, control);
+        value = effect =
+            graph()->NewNode(common()->FinishRegion(), value, effect);
       } else if (property_details.representation().IsSmi()) {
         // Ensure that value is stored as smi.
         value = boilerplate_value->IsUninitialized()
                     ? jsgraph()->ZeroConstant()
                     : jsgraph()->Constant(boilerplate_value);
       } else {
         value = jsgraph()->Constant(boilerplate_value);
       }
     }
     inobject_fields.push_back(std::make_pair(access, value));
@@ skipping 100 matching lines @@
   ElementAccess const access =
       (elements_map->instance_type() == FIXED_DOUBLE_ARRAY_TYPE)
           ? AccessBuilder::ForFixedDoubleArrayElement()
           : AccessBuilder::ForFixedArrayElement();
   for (int i = 0; i < elements_length; ++i) {
     builder.Store(access, jsgraph()->Constant(i), elements_values[i]);
   }
   return builder.Finish();
 }
 
-Node* JSCreateLowering::AllocateMutableHeapNumber(double value, Node* effect,
-                                                  Node* control) {
-  // TODO(turbofan): Support inline allocation of MutableHeapNumber
-  // (requires proper alignment on Allocate, and Begin/FinishRegion).
-  Callable callable = CodeFactory::AllocateMutableHeapNumber(isolate());
-  CallDescriptor* desc = Linkage::GetStubCallDescriptor(
-      isolate(), jsgraph()->zone(), callable.descriptor(), 0,
-      CallDescriptor::kNoFlags, Operator::kNoThrow);
-  Node* result = effect = graph()->NewNode(
-      common()->Call(desc), jsgraph()->HeapConstant(callable.code()),
-      jsgraph()->NoContextConstant(), effect, control);
-  effect = graph()->NewNode(
-      simplified()->StoreField(AccessBuilder::ForHeapNumberValue()), result,
-      jsgraph()->Constant(value), effect, control);
-  return result;
-}
-
 MaybeHandle<LiteralsArray> JSCreateLowering::GetSpecializationLiterals(
     Node* node) {
   Node* const closure = NodeProperties::GetValueInput(node, 0);
   switch (closure->opcode()) {
     case IrOpcode::kHeapConstant: {
       Handle<HeapObject> object = OpParameter<Handle<HeapObject>>(closure);
       return handle(Handle<JSFunction>::cast(object)->literals());
     }
     case IrOpcode::kParameter: {
       int const index = ParameterIndexOf(closure->op());
@@ skipping 29 matching lines @@
   return jsgraph()->simplified();
 }
 
 MachineOperatorBuilder* JSCreateLowering::machine() const {
   return jsgraph()->machine();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8