Elide write barriers and remove some heap_object->GetHeap() calls on

src/objects-inl.h

Index: src/objects-inl.h
===================================================================
--- src/objects-inl.h	(revision 10171)
+++ src/objects-inl.h	(working copy)
@@ -90,7 +90,7 @@
   type* holder::name() { return type::cast(READ_FIELD(this, offset)); } \
   void holder::set_##name(type* value, WriteBarrierMode mode) {         \
     WRITE_FIELD(this, offset, value);                                   \
-    CONDITIONAL_WRITE_BARRIER(GetHeap(), this, offset, value, mode);    \
+    CONDITIONAL_WRITE_BARRIER(this, offset, value, mode);               \
   }
 
 
@@ -846,15 +846,25 @@
 #define WRITE_FIELD(p, offset, value) \
   (*reinterpret_cast<Object**>(FIELD_ADDR(p, offset)) = value)
 
-#define WRITE_BARRIER(heap, object, offset, value)                      \
-  heap->incremental_marking()->RecordWrite(                             \
-      object, HeapObject::RawField(object, offset), value);             \
-  if (heap->InNewSpace(value)) {                                        \
-    heap->RecordWrite(object->address(), offset);                       \
+#define WRITE_BARRIER(object, offset, value)                            \
+  Address value_addr = reinterpret_cast<HeapObject*>(value)->address(); \
+  if (!value->IsSmi() && Page::FromAddress(value_addr)->IsFlagSet(      \
+        MemoryChunk::POINTERS_TO_HERE_ARE_INTERESTING)) {               \
+    Heap* heap = object->GetHeap();                                     \
+    heap->incremental_marking()->RecordWrite(                           \
+        object, HeapObject::RawField(object, offset), value);           \
+    if (heap->InNewSpace(value)) {                                      \
+      heap->RecordWrite(object->address(), offset);                     \
+    }                                                                   \
   }
 
-#define CONDITIONAL_WRITE_BARRIER(heap, object, offset, value, mode)    \
-  if (mode == UPDATE_WRITE_BARRIER) {                                   \
+#define CONDITIONAL_WRITE_BARRIER(object, offset, value, mode)          \
+  Address value_addr = reinterpret_cast<HeapObject*>(value)->address(); \
+  if (mode == UPDATE_WRITE_BARRIER &&                                   \
+      !value->IsSmi() &&                                                \
+      Page::FromAddress(value_addr)->IsFlagSet(                         \
+          MemoryChunk::POINTERS_TO_HERE_ARE_INTERESTING)) {             \
+    Heap* heap = object->GetHeap();                                     \
     heap->incremental_marking()->RecordWrite(                           \
       object, HeapObject::RawField(object, offset), value);             \
     if (heap->InNewSpace(value)) {                                      \
@@ -862,6 +872,15 @@
     }                                                                   \
   }
 
+#define CONDITIONAL_WRITE_BARRIER_WITH_HEAP(heap, object, offset, value, mode) \
+  if (mode == UPDATE_WRITE_BARRIER) {                                          \
+    heap->incremental_marking()->RecordWrite(                                  \
+      object, HeapObject::RawField(object, offset), value);                    \
+    if (heap->InNewSpace(value)) {                                             \
+      heap->RecordWrite(object->address(), offset);                            \
+    }                                                                          \
+  }
+
 #ifndef V8_TARGET_ARCH_MIPS
   #define READ_DOUBLE_FIELD(p, offset) \
     (*reinterpret_cast<double*>(FIELD_ADDR(p, offset)))
@@ -1258,7 +1277,7 @@
   ValidateSmiOnlyElements();
 #endif
   WRITE_FIELD(this, kElementsOffset, value);
-  CONDITIONAL_WRITE_BARRIER(GetHeap(), this, kElementsOffset, value, mode);
+  CONDITIONAL_WRITE_BARRIER(this, kElementsOffset, value, mode);
 }
 
 
@@ -1381,7 +1400,7 @@
   // to adjust the index here.
   int offset = GetHeaderSize() + (kPointerSize * index);
   WRITE_FIELD(this, offset, value);
-  WRITE_BARRIER(GetHeap(), this, offset, value);
+  WRITE_BARRIER(this, offset, value);
 }
 
 
@@ -1417,7 +1436,7 @@
   if (index < 0) {
     int offset = map()->instance_size() + (index * kPointerSize);
     WRITE_FIELD(this, offset, value);
-    WRITE_BARRIER(GetHeap(), this, offset, value);
+    WRITE_BARRIER(this, offset, value);
   } else {
     ASSERT(index < properties()->length());
     properties()->set(index, value);
@@ -1451,7 +1470,7 @@
   ASSERT(index < 0);
   int offset = map()->instance_size() + (index * kPointerSize);
   WRITE_FIELD(this, offset, value);
-  CONDITIONAL_WRITE_BARRIER(GetHeap(), this, offset, value, mode);
+  CONDITIONAL_WRITE_BARRIER(this, offset, value, mode);
   return value;
 }
 
@@ -1562,7 +1581,7 @@
   ASSERT(index >= 0 && index < this->length());
   int offset = kHeaderSize + index * kPointerSize;
   WRITE_FIELD(this, offset, value);
-  WRITE_BARRIER(GetHeap(), this, offset, value);
+  WRITE_BARRIER(this, offset, value);
 }
 
 
@@ -1699,7 +1718,7 @@
   ASSERT(index >= 0 && index < this->length());
   int offset = kHeaderSize + index * kPointerSize;
   WRITE_FIELD(this, offset, value);
-  CONDITIONAL_WRITE_BARRIER(GetHeap(), this, offset, value, mode);
+  CONDITIONAL_WRITE_BARRIER(this, offset, value, mode);
 }
 
 
@@ -1762,7 +1781,7 @@
                                WriteBarrierMode mode) {
   int offset = kHeaderSize + index * kPointerSize;
   WRITE_FIELD(this, offset, value);
-  CONDITIONAL_WRITE_BARRIER(heap, this, offset, value, mode);
+  CONDITIONAL_WRITE_BARRIER_WITH_HEAP(heap, this, offset, value, mode);
 }
 
 
@@ -2277,7 +2296,7 @@
 
 void ConsString::set_first(String* value, WriteBarrierMode mode) {
   WRITE_FIELD(this, kFirstOffset, value);
-  CONDITIONAL_WRITE_BARRIER(GetHeap(), this, kFirstOffset, value, mode);
+  CONDITIONAL_WRITE_BARRIER(this, kFirstOffset, value, mode);
 }
 
 
@@ -2293,7 +2312,7 @@
 
 void ConsString::set_second(String* value, WriteBarrierMode mode) {
   WRITE_FIELD(this, kSecondOffset, value);
-  CONDITIONAL_WRITE_BARRIER(GetHeap(), this, kSecondOffset, value, mode);
+  CONDITIONAL_WRITE_BARRIER(this, kSecondOffset, value, mode);
 }
 
 
@@ -3209,7 +3228,7 @@
 void Map::set_prototype(Object* value, WriteBarrierMode mode) {
   ASSERT(value->IsNull() || value->IsJSReceiver());
   WRITE_FIELD(this, kPrototypeOffset, value);
-  CONDITIONAL_WRITE_BARRIER(GetHeap(), this, kPrototypeOffset, value, mode);
+  CONDITIONAL_WRITE_BARRIER(this, kPrototypeOffset, value, mode);
 }
 
 
@@ -3258,7 +3277,7 @@
   }
   ASSERT(!is_shared());
   WRITE_FIELD(this, kInstanceDescriptorsOrBitField3Offset, value);
-  CONDITIONAL_WRITE_BARRIER(
+  CONDITIONAL_WRITE_BARRIER_WITH_HEAP(
       heap, this, kInstanceDescriptorsOrBitField3Offset, value, mode);
 }
 
@@ -3630,7 +3649,7 @@
 
 void SharedFunctionInfo::set_code(Code* value, WriteBarrierMode mode) {
   WRITE_FIELD(this, kCodeOffset, value);
-  CONDITIONAL_WRITE_BARRIER(value->GetHeap(), this, kCodeOffset, value, mode);
+  CONDITIONAL_WRITE_BARRIER(this, kCodeOffset, value, mode);
 }
 
 
@@ -3642,8 +3661,7 @@
 void SharedFunctionInfo::set_scope_info(ScopeInfo* value,
                                         WriteBarrierMode mode) {
   WRITE_FIELD(this, kScopeInfoOffset, reinterpret_cast<Object*>(value));
-  CONDITIONAL_WRITE_BARRIER(GetHeap(),
-                            this,
+  CONDITIONAL_WRITE_BARRIER(this,
                             kScopeInfoOffset,
                             reinterpret_cast<Object*>(value),
                             mode);
@@ -3789,7 +3807,7 @@
 void JSFunction::set_context(Object* value) {
   ASSERT(value->IsUndefined() || value->IsContext());
   WRITE_FIELD(this, kContextOffset, value);
-  WRITE_BARRIER(GetHeap(), this, kContextOffset, value);
+  WRITE_BARRIER(this, kContextOffset, value);
 }
 
 ACCESSORS(JSFunction, prototype_or_initial_map, Object,
@@ -3892,7 +3910,7 @@
                                               Object* value) {
   ASSERT(id < kJSBuiltinsCount);  // id is unsigned.
   WRITE_FIELD(this, OffsetOfFunctionWithId(id), value);
-  WRITE_BARRIER(GetHeap(), this, OffsetOfFunctionWithId(id), value);
+  WRITE_BARRIER(this, OffsetOfFunctionWithId(id), value);
 }