[heap] New Dijkstra marking write barrier.

A.x = B
Change from mark grey A to mark grey B.

BUG=

Review URL: https://codereview.chromium.org/1409813007

Cr-Commit-Position: refs/heads/master@{#32765}

src/heap/incremental-marking.cc

@@ -47,39 +47,22 @@ IncrementalMarking::IncrementalMarking(Heap* heap)
       request_type_(COMPLETE_MARKING) {}
 
 
-bool IncrementalMarking::BaseRecordWrite(HeapObject* obj, Object** slot,
-                                         Object* value) {
+bool IncrementalMarking::BaseRecordWrite(HeapObject* obj, Object* value) {
   HeapObject* value_heap_obj = HeapObject::cast(value);
   MarkBit value_bit = Marking::MarkBitFrom(value_heap_obj);
-  if (Marking::IsWhite(value_bit)) {
   MarkBit obj_bit = Marking::MarkBitFrom(obj);
-    if (Marking::IsBlack(obj_bit)) {
-      MemoryChunk* chunk = MemoryChunk::FromAddress(obj->address());
-      if (chunk->IsFlagSet(MemoryChunk::HAS_PROGRESS_BAR)) {
-        if (chunk->IsLeftOfProgressBar(slot)) {
+  bool is_black = Marking::IsBlack(obj_bit);
+  if (is_black && Marking::IsWhite(value_bit)) {
     WhiteToGreyAndPush(value_heap_obj, value_bit);
     RestartIfNotMarking();
-        } else {
-          return false;
-        }
-      } else {
-        BlackToGreyAndUnshift(obj, obj_bit);
-        RestartIfNotMarking();
-        return false;
-      }
-    } else {
-      return false;
   }
-  }
-  if (!is_compacting_) return false;
-  MarkBit obj_bit = Marking::MarkBitFrom(obj);
-  return Marking::IsBlack(obj_bit);
+  return is_compacting_ && is_black;
 }
 
 
 void IncrementalMarking::RecordWriteSlow(HeapObject* obj, Object** slot,
                                          Object* value) {
-  if (BaseRecordWrite(obj, slot, value) && slot != NULL) {
+  if (BaseRecordWrite(obj, value) && slot != NULL) {
     // Object is not going to be rescanned we need to record the slot.
     heap_->mark_compact_collector()->RecordSlot(obj, slot, value);
   }
@@ -128,7 +111,7 @@ void IncrementalMarking::RecordCodeTargetPatch(Address pc, HeapObject* value) {
 void IncrementalMarking::RecordWriteOfCodeEntrySlow(JSFunction* host,
                                                     Object** slot,
                                                     Code* value) {
-  if (BaseRecordWrite(host, slot, value)) {
+  if (BaseRecordWrite(host, value)) {
     DCHECK(slot != NULL);
     heap_->mark_compact_collector()->RecordCodeEntrySlot(
         host, reinterpret_cast<Address>(slot), value);
@@ -139,25 +122,11 @@ void IncrementalMarking::RecordWriteOfCodeEntrySlow(JSFunction* host,
 void IncrementalMarking::RecordWriteIntoCodeSlow(HeapObject* obj,
                                                  RelocInfo* rinfo,
                                                  Object* value) {
-  MarkBit value_bit = Marking::MarkBitFrom(HeapObject::cast(value));
-  if (Marking::IsWhite(value_bit)) {
-    MarkBit obj_bit = Marking::MarkBitFrom(obj);
-    if (Marking::IsBlack(obj_bit)) {
-      BlackToGreyAndUnshift(obj, obj_bit);
-      RestartIfNotMarking();
-    }
-    // Object is either grey or white.  It will be scanned if survives.
-    return;
-  }
-
-  if (is_compacting_) {
-    MarkBit obj_bit = Marking::MarkBitFrom(obj);
-    if (Marking::IsBlack(obj_bit)) {
+  if (BaseRecordWrite(obj, value)) {
       // Object is not going to be rescanned.  We need to record the slot.
       heap_->mark_compact_collector()->RecordRelocSlot(rinfo,
                                                        Code::cast(value));
   }
-  }
 }
 
 

src/heap/incremental-marking.h

@@ -159,7 +159,7 @@ class IncrementalMarking {
   // No slots in white objects should be recorded, as some slots are typed and
   // cannot be interpreted correctly if the underlying object does not survive
   // the incremental cycle (stays white).
-  INLINE(bool BaseRecordWrite(HeapObject* obj, Object** slot, Object* value));
+  INLINE(bool BaseRecordWrite(HeapObject* obj, Object* value));
   INLINE(void RecordWrite(HeapObject* obj, Object** slot, Object* value));
   INLINE(void RecordWriteIntoCode(HeapObject* obj, RelocInfo* rinfo,
                                   Object* value));

src/heap/spaces.h

@@ -631,13 +631,6 @@ class MemoryChunk {
     }
   }
 
-  bool IsLeftOfProgressBar(Object** slot) {
-    Address slot_address = reinterpret_cast<Address>(slot);
-    DCHECK(slot_address > this->address());
-    return (slot_address - (this->address() + kObjectStartOffset)) <
-           progress_bar();
-  }
-
   size_t size() const { return size_; }
 
   void set_size(size_t size) { size_ = size; }