Get rid of HStoreNamedField::SkipWriteBarrier().

The write barrier elimination does the right thing now, so
we can get rid of this hack.

R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/296023002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21384 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/code-stubs-hydrogen.cc

@@ -500,7 +500,7 @@ HValue* CodeStubGraphBuilder<CreateAllocationSiteStub>::BuildCodeStub() {
   // Store an empty fixed array for the code dependency.
   HConstant* empty_fixed_array =
     Add<HConstant>(isolate()->factory()->empty_fixed_array());
-  HStoreNamedField* store = Add<HStoreNamedField>(
+  Add<HStoreNamedField>(
       object,
       HObjectAccess::ForAllocationSiteOffset(
           AllocationSite::kDependentCodeOffset),
@@ -512,10 +512,15 @@ HValue* CodeStubGraphBuilder<CreateAllocationSiteStub>::BuildCodeStub() {
   HValue* site = Add<HLoadNamedField>(
       site_list, static_cast<HValue*>(NULL),
       HObjectAccess::ForAllocationSiteList());
-  store = Add<HStoreNamedField>(object,
+  // TODO(mvstanton): This is a store to a weak pointer, which we may want to
+  // mark as such in order to skip the write barrier, once we have a unified
+  // system for weakness. For now we decided to keep it like this because having
+  // an initial write barrier backed store makes this pointer strong until the
+  // next GC, and allocation sites are designed to survive several GCs anyway.
+  Add<HStoreNamedField>(
+      object,
       HObjectAccess::ForAllocationSiteOffset(AllocationSite::kWeakNextOffset),
       site);
-  store->SkipWriteBarrier();
   Add<HStoreNamedField>(site_list, HObjectAccess::ForAllocationSiteList(),
                         object);
 

src/hydrogen-instructions.h

@@ -6704,11 +6704,6 @@ class HStoreNamedField V8_FINAL : public HTemplateInstruction<2> {
   }
   virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  void SkipWriteBarrier() { write_barrier_mode_ = SKIP_WRITE_BARRIER; }
-  bool IsSkipWriteBarrier() const {
-    return write_barrier_mode_ == SKIP_WRITE_BARRIER;
-  }
-
   HValue* object() const { return OperandAt(0); }
   HValue* value() const { return OperandAt(1); }
 
@@ -6717,7 +6712,6 @@ class HStoreNamedField V8_FINAL : public HTemplateInstruction<2> {
   StoreFieldOrKeyedMode store_mode() const { return store_mode_; }
 
   bool NeedsWriteBarrier() {
-    if (IsSkipWriteBarrier()) return false;
     if (field_representation().IsDouble()) return false;
     if (field_representation().IsSmi()) return false;
     if (field_representation().IsInteger32()) return false;
@@ -6742,7 +6736,6 @@ class HStoreNamedField V8_FINAL : public HTemplateInstruction<2> {
                    StoreFieldOrKeyedMode store_mode = INITIALIZING_STORE)
       : access_(access),
         new_space_dominator_(NULL),
-        write_barrier_mode_(UPDATE_WRITE_BARRIER),
         store_mode_(store_mode) {
     // Stores to a non existing in-object property are allowed only to the
     // newly allocated objects (via HAllocate or HInnerAllocatedObject).
@@ -6755,7 +6748,6 @@ class HStoreNamedField V8_FINAL : public HTemplateInstruction<2> {
 
   HObjectAccess access_;
   HValue* new_space_dominator_;
-  WriteBarrierMode write_barrier_mode_ : 1;
   StoreFieldOrKeyedMode store_mode_ : 1;
 };
 

src/hydrogen.cc

@@ -1560,7 +1560,9 @@ HValue* HGraphBuilder::BuildRegExpConstructResult(HValue* length,
   HValue* native_context = Add<HLoadNamedField>(
       global_object, static_cast<HValue*>(NULL),
       HObjectAccess::ForGlobalObjectNativeContext());
-  AddStoreMapNoWriteBarrier(result, Add<HLoadNamedField>(
+  Add<HStoreNamedField>(
+      result, HObjectAccess::ForMap(),
+      Add<HLoadNamedField>(
           native_context, static_cast<HValue*>(NULL),
           HObjectAccess::ForContextSlot(Context::REGEXP_RESULT_MAP_INDEX)));
   Add<HStoreNamedField>(
@@ -1581,8 +1583,7 @@ HValue* HGraphBuilder::BuildRegExpConstructResult(HValue* length,
       input);
 
   // Initialize the elements header.
-  AddStoreMapConstantNoWriteBarrier(elements,
-                                    isolate()->factory()->fixed_array_map());
+  AddStoreMapConstant(elements, isolate()->factory()->fixed_array_map());
   Add<HStoreNamedField>(elements, HObjectAccess::ForFixedArrayLength(), length);
 
   // Initialize the elements contents with undefined.
@@ -1832,14 +1833,16 @@ HValue* HGraphBuilder::BuildCreateConsString(
   if_onebyte.Then();
   {
     // We can safely skip the write barrier for storing the map here.
-    Handle<Map> map = isolate()->factory()->cons_ascii_string_map();
-    AddStoreMapConstantNoWriteBarrier(result, map);
+    Add<HStoreNamedField>(
+        result, HObjectAccess::ForMap(),
+        Add<HConstant>(isolate()->factory()->cons_ascii_string_map()));
   }
   if_onebyte.Else();
   {
     // We can safely skip the write barrier for storing the map here.
-    Handle<Map> map = isolate()->factory()->cons_string_map();
-    AddStoreMapConstantNoWriteBarrier(result, map);
+    Add<HStoreNamedField>(
+        result, HObjectAccess::ForMap(),
+        Add<HConstant>(isolate()->factory()->cons_string_map()));
   }
   if_onebyte.End();
 
@@ -1998,9 +2001,7 @@ HValue* HGraphBuilder::BuildUncheckedStringAdd(
       // STRING_TYPE or ASCII_STRING_TYPE here, so we just use STRING_TYPE here.
       HAllocate* result = BuildAllocate(
           size, HType::String(), STRING_TYPE, allocation_mode);
-
-      // We can safely skip the write barrier for storing map here.
-      AddStoreMapNoWriteBarrier(result, map);
+      Add<HStoreNamedField>(result, HObjectAccess::ForMap(), map);
 
       // Initialize the string fields.
       Add<HStoreNamedField>(result, HObjectAccess::ForStringHashField(),
@@ -2307,7 +2308,7 @@ void HGraphBuilder::BuildInitializeElementsHeader(HValue* elements,
       ? factory->fixed_double_array_map()
       : factory->fixed_array_map();
 
-  AddStoreMapConstant(elements, map);
+  Add<HStoreNamedField>(elements, HObjectAccess::ForMap(), Add<HConstant>(map));
   Add<HStoreNamedField>(elements, HObjectAccess::ForFixedArrayLength(),
                         capacity);
 }
@@ -2812,11 +2813,9 @@ void HGraphBuilder::BuildCreateAllocationMemento(
     // This smi value is reset to zero after every gc, overflow isn't a problem
     // since the counter is bounded by the new space size.
     memento_create_count->ClearFlag(HValue::kCanOverflow);
-    HStoreNamedField* store = Add<HStoreNamedField>(
+    Add<HStoreNamedField>(
         allocation_site, HObjectAccess::ForAllocationSiteOffset(
             AllocationSite::kPretenureCreateCountOffset), memento_create_count);
-    // No write barrier needed to store a smi.
-    store->SkipWriteBarrier();
   }
 }
 
@@ -3034,13 +3033,6 @@ HValue* HGraphBuilder::JSArrayBuilder::AllocateArray(HValue* size_in_bytes,
 }
 
 
-HStoreNamedField* HGraphBuilder::AddStoreMapConstant(HValue *object,
-                                                     Handle<Map> map) {
-  return Add<HStoreNamedField>(object, HObjectAccess::ForMap(),
-                               Add<HConstant>(map));
-}
-
-
 HValue* HGraphBuilder::AddLoadJSBuiltin(Builtins::JavaScript builtin) {
   HValue* global_object = Add<HLoadNamedField>(
       context(), static_cast<HValue*>(NULL),

src/hydrogen.h

@@ -1388,18 +1388,9 @@ class HGraphBuilder {
 
   HInstruction* AddLoadStringInstanceType(HValue* string);
   HInstruction* AddLoadStringLength(HValue* string);
-  HStoreNamedField* AddStoreMapNoWriteBarrier(HValue* object, HValue* map) {
-    HStoreNamedField* store_map = Add<HStoreNamedField>(
-        object, HObjectAccess::ForMap(), map);
-    store_map->SkipWriteBarrier();
-    return store_map;
-  }
-  HStoreNamedField* AddStoreMapConstant(HValue* object, Handle<Map> map);
-  HStoreNamedField* AddStoreMapConstantNoWriteBarrier(HValue* object,
-                                                      Handle<Map> map) {
-    HStoreNamedField* store_map = AddStoreMapConstant(object, map);
-    store_map->SkipWriteBarrier();
-    return store_map;
+  HStoreNamedField* AddStoreMapConstant(HValue* object, Handle<Map> map) {
+    return Add<HStoreNamedField>(object, HObjectAccess::ForMap(),
+                                 Add<HConstant>(map));
   }
   HLoadNamedField* AddLoadElements(HValue* object,
                                    HValue* dependency = NULL);