From: hpayer <hpayer@chromium.org>
Date: Wed, 6 May 2015 14:35:02 +0000 (-0700)
Subject: Revert of New insertion write barrier. (patchset #3 id:200001 of https://codereview... 
X-Git-Tag: upstream/4.7.83~2775
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=74654d309816211964c7bac528a6c263aa54a475;p=platform%2Fupstream%2Fv8.git

Revert of New insertion write barrier. (patchset #3 id:200001 of https://codereview.chromium.org/1073953006/)

Reason for revert:
Various performance regressions.

Original issue's description:
> New insertion write barrier.
>
> BUG=
>
> Committed: https://crrev.com/6e9e2c08292b553602c74b16b8ccff4e4ccac003
> Cr-Commit-Position: refs/heads/master@{#28199}

TBR=ulan@chromium.org,erikcorry@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/1131583002

Cr-Commit-Position: refs/heads/master@{#28265}
---

diff --git a/src/heap/incremental-marking-inl.h b/src/heap/incremental-marking-inl.h
index b9cfe1d..42b3dcb 100644
--- a/src/heap/incremental-marking-inl.h
+++ b/src/heap/incremental-marking-inl.h
@@ -16,8 +16,24 @@ bool IncrementalMarking::BaseRecordWrite(HeapObject* obj, Object** slot,
   HeapObject* value_heap_obj = HeapObject::cast(value);
   MarkBit value_bit = Marking::MarkBitFrom(value_heap_obj);
   if (Marking::IsWhite(value_bit)) {
-    WhiteToGreyAndPush(value_heap_obj, value_bit);
-    RestartIfNotMarking();
+    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)) {
+          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);
diff --git a/src/heap/spaces.h b/src/heap/spaces.h
index de8e4b0..494d05c 100644
--- a/src/heap/spaces.h
+++ b/src/heap/spaces.h
@@ -508,6 +508,13 @@ 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();
+  }
+
   static void IncrementLiveBytesFromGC(Address address, int by) {
     MemoryChunk::FromAddress(address)->IncrementLiveBytes(by);
   }