Reviewers: Vyacheslav Egorov,
Description:
Unify UpdateSlotsOnPage and SweepPrecisely.
[email protected]
BUG=v8:1610
Please review this at http://codereview.chromium.org/7706004/
SVN Base: https://v8.googlecode.com/svn/branches/experimental/gc
Affected files:
M src/mark-compact.cc
Index: src/mark-compact.cc
diff --git a/src/mark-compact.cc b/src/mark-compact.cc
index
526d3a3993268c955ad39f6b23d860311eb5fda6..79999989930e8aa153f6e794323206b3e5df6656
100644
--- a/src/mark-compact.cc
+++ b/src/mark-compact.cc
@@ -2610,13 +2610,17 @@ static inline void UpdateSlotsInRange(Object**
start, Object** end) {
}
-static void UpdateSlotsOnPage(Page* p, ObjectVisitor* visitor) {
- // TODO(gc) this is basically clone of SweepPrecisely
- PagedSpace* space = static_cast<PagedSpace*>(p->owner());
+// Sweep a space precisely. After this has been done the space can
+// be iterated precisely, hitting only the live objects. Code space
+// is always swept precisely because we want to be able to iterate
+// over it. Map space is swept precisely, because it is not compacted.
+// Slots in live objects pointing into evacuation candidates are updated
+// if requested.
+static void SweepPrecisely(PagedSpace* space, Page* p, bool update_slots) {
+ ASSERT(!p->IsEvacuationCandidate() && !p->WasSwept());
MarkBit::CellType* cells = p->markbits()->cells();
p->ClearFlag(MemoryChunk::WAS_SWEPT_CONSERVATIVELY);
- p->ClearFlag(MemoryChunk::RESCAN_ON_EVACUATION);
p->MarkSwept();
int last_cell_index =
@@ -2647,8 +2651,10 @@ static void UpdateSlotsOnPage(Page* p,
ObjectVisitor* visitor) {
HeapObject* live_object = HeapObject::FromAddress(free_end);
ASSERT(Marking::IsBlack(Marking::MarkBitFrom(live_object)));
int size = live_object->Size();
- UpdateSlotsInRange(HeapObject::RawField(live_object, kPointerSize),
- HeapObject::RawField(live_object, size));
+ if (update_slots) {
+ UpdateSlotsInRange(HeapObject::RawField(live_object, kPointerSize),
+ HeapObject::RawField(live_object, size));
+ }
free_start = free_end + size;
}
}
@@ -2708,7 +2714,9 @@ void
MarkCompactCollector::EvacuateNewSpaceAndCandidates() {
SlotsBuffer::SizeOfChain(p->slots_buffer()));
}
} else {
- UpdateSlotsOnPage(p, &updating_visitor);
+ PagedSpace* space = static_cast<PagedSpace*>(p->owner());
+ p->ClearFlag(MemoryChunk::RESCAN_ON_EVACUATION);
+ SweepPrecisely(space, p, true);
}
}
@@ -3174,53 +3182,6 @@ intptr_t
MarkCompactCollector::SweepConservatively(PagedSpace* space, Page* p) {
}
-// Sweep a space precisely. After this has been done the space can
-// be iterated precisely, hitting only the live objects. Code space
-// is always swept precisely because we want to be able to iterate
-// over it. Map space is swept precisely, because it is not compacted.
-static void SweepPrecisely(PagedSpace* space,
- Page* p) {
- ASSERT(!p->IsEvacuationCandidate() && !p->WasSwept());
- MarkBit::CellType* cells = p->markbits()->cells();
-
- p->ClearFlag(MemoryChunk::WAS_SWEPT_CONSERVATIVELY);
-
- int last_cell_index =
- Bitmap::IndexToCell(
- Bitmap::CellAlignIndex(
- p->AddressToMarkbitIndex(p->ObjectAreaEnd())));
-
- int cell_index = Page::kFirstUsedCell;
- Address free_start = p->ObjectAreaStart();
- ASSERT(reinterpret_cast<intptr_t>(free_start) % (32 * kPointerSize) ==
0);
- Address object_address = p->ObjectAreaStart();
- int offsets[16];
-
- for (cell_index = Page::kFirstUsedCell;
- cell_index < last_cell_index;
- cell_index++, object_address += 32 * kPointerSize) {
- ASSERT((unsigned)cell_index ==
- Bitmap::IndexToCell(
- Bitmap::CellAlignIndex(
- p->AddressToMarkbitIndex(object_address))));
- int live_objects = MarkWordToObjectStarts(cells[cell_index], offsets);
- int live_index = 0;
- for ( ; live_objects != 0; live_objects--) {
- Address free_end = object_address + offsets[live_index++] *
kPointerSize;
- if (free_end != free_start) {
- space->Free(free_start, static_cast<int>(free_end - free_start));
- }
- HeapObject* live_object = HeapObject::FromAddress(free_end);
- ASSERT(Marking::IsBlack(Marking::MarkBitFrom(live_object)));
- free_start = free_end + live_object->Size();
- }
- }
- if (free_start != p->ObjectAreaEnd()) {
- space->Free(free_start, static_cast<int>(p->ObjectAreaEnd() -
free_start));
- }
-}
-
-
void MarkCompactCollector::SweepSpace(PagedSpace* space,
SweeperType sweeper) {
space->set_was_swept_conservatively(sweeper == CONSERVATIVE ||
@@ -3262,7 +3223,7 @@ void MarkCompactCollector::SweepSpace(PagedSpace*
space,
break;
}
case PRECISE: {
- SweepPrecisely(space, p);
+ SweepPrecisely(space, p, false);
break;
}
default: {
--
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