Reviewers: Hannes Payer,
Message:
PTAL
Description:
Use the HeapObjectIterator to scan-on-scavenge map pages.
Deserializing the partial snapshot may prematurely stop using a map page,
adding
a free-space filler at the end. Scan-on-scavenge of map-space did not expect
anything but maps, and would interpret the uninitialized memory as pointers.
Using the heap iterator we can skip over free space and only visit maps.
BUG=390732
Please review this at https://codereview.chromium.org/364063007/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files (+12, -57 lines):
M src/store-buffer.h
M src/store-buffer.cc
Index: src/store-buffer.cc
diff --git a/src/store-buffer.cc b/src/store-buffer.cc
index
4ab5c33c8cc439b59033c85c4be1ae5b92c67d49..a21ac2a76ea2d4d2c29ea42b4bf7d9ca4074263c
100644
--- a/src/store-buffer.cc
+++ b/src/store-buffer.cc
@@ -417,49 +417,6 @@ static inline Address MapEndAlign(Address addr) {
}
-void StoreBuffer::FindPointersToNewSpaceInMaps(
- Address start,
- Address end,
- ObjectSlotCallback slot_callback,
- bool clear_maps) {
- ASSERT(MapStartAlign(start) == start);
- ASSERT(MapEndAlign(end) == end);
-
- Address map_address = start;
- while (map_address < end) {
- ASSERT(!heap_->InNewSpace(Memory::Object_at(map_address)));
- ASSERT(Memory::Object_at(map_address)->IsMap());
-
- Address pointer_fields_start = map_address +
Map::kPointerFieldsBeginOffset;
- Address pointer_fields_end = map_address +
Map::kPointerFieldsEndOffset;
-
- FindPointersToNewSpaceInRegion(pointer_fields_start,
- pointer_fields_end,
- slot_callback,
- clear_maps);
- map_address += Map::kSize;
- }
-}
-
-
-void StoreBuffer::FindPointersToNewSpaceInMapsRegion(
- Address start,
- Address end,
- ObjectSlotCallback slot_callback,
- bool clear_maps) {
- Address map_aligned_start = MapStartAlign(start);
- Address map_aligned_end = MapEndAlign(end);
-
- ASSERT(map_aligned_start == start);
- ASSERT(map_aligned_start <= map_aligned_end && map_aligned_end <= end);
-
- FindPointersToNewSpaceInMaps(map_aligned_start,
- map_aligned_end,
- slot_callback,
- clear_maps);
-}
-
-
void StoreBuffer::IteratePointersInStoreBuffer(
ObjectSlotCallback slot_callback,
bool clear_maps) {
@@ -549,8 +506,18 @@ void
StoreBuffer::IteratePointersToNewSpace(ObjectSlotCallback slot_callback,
Address start = page->area_start();
Address end = page->area_end();
if (owner == heap_->map_space()) {
- FindPointersToNewSpaceInMapsRegion(
- start, end, slot_callback, clear_maps);
+ ASSERT(page->WasSweptPrecisely());
+ HeapObjectIterator iterator(page, NULL);
+ for (HeapObject* heap_object = iterator.Next(); heap_object !=
NULL;
+ heap_object = iterator.Next()) {
+ // We skip free space objects.
+ if (!heap_object->IsFiller()) {
+ FindPointersToNewSpaceInRegion(
+ heap_object->address() + HeapObject::kHeaderSize,
+ heap_object->address() + heap_object->Size(),
slot_callback,
+ clear_maps);
+ }
+ }
} else {
FindPointersToNewSpaceInRegion(
start, end, slot_callback, clear_maps);
Index: src/store-buffer.h
diff --git a/src/store-buffer.h b/src/store-buffer.h
index
00eb86a805204ef2a0666eb6a726345367c4c209..9101c0eb892435d2ba07950d6906416d1fc7610b
100644
--- a/src/store-buffer.h
+++ b/src/store-buffer.h
@@ -167,18 +167,6 @@ class StoreBuffer {
RegionCallback region_callback,
ObjectSlotCallback slot_callback);
- void FindPointersToNewSpaceInMaps(
- Address start,
- Address end,
- ObjectSlotCallback slot_callback,
- bool clear_maps);
-
- void FindPointersToNewSpaceInMapsRegion(
- Address start,
- Address end,
- ObjectSlotCallback slot_callback,
- bool clear_maps);
-
void IteratePointersInStoreBuffer(ObjectSlotCallback slot_callback,
bool clear_maps);
--
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