Reviewers: Michael Starzinger,
Description:
Don' left-trim arrays when concurrent sweeping is active.
BUG=
Please review this at https://codereview.chromium.org/207613004/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files (+39, -4 lines):
M src/builtins.cc
M src/mark-compact.h
M src/mark-compact.cc
M src/spaces.h
Index: src/builtins.cc
diff --git a/src/builtins.cc b/src/builtins.cc
index
b48de7f2cd52378eb5e706e1951fba1031192c4f..79b3f3bf38bfc813a42f992fc72c8b348887a7b1
100644
--- a/src/builtins.cc
+++ b/src/builtins.cc
@@ -610,7 +610,7 @@ BUILTIN(ArrayShift) {
first = heap->undefined_value();
}
- if (!heap->lo_space()->Contains(elms_obj)) {
+ if (!heap->mark_compact_collector()->CanMoveObjectStart(elms_obj)) {
array->set_elements(LeftTrimFixedArray(heap, elms_obj, 1));
} else {
// Shift the elements.
@@ -950,8 +950,23 @@ BUILTIN(ArraySplice) {
heap->MoveElements(elms, delta, 0, actual_start);
}
- elms_obj = LeftTrimFixedArray(heap, elms_obj, delta);
-
+ if (heap->mark_compact_collector()->CanMoveObjectStart(elms_obj)) {
+ // On the fast path we move the start of the object in memory.
+ elms_obj = LeftTrimFixedArray(heap, elms_obj, delta);
+ } else {
+ // This is the slow path. We are going to move the elemetns to the
left
+ // by copying them. For trimmed values we store the hole.
+ if (elms_obj->IsFixedDoubleArray()) {
+ FixedDoubleArray* elms = FixedDoubleArray::cast(elms_obj);
+ MoveDoubleElements(elms, 0, elms, delta, len - delta);
+ FillWithHoles(elms, len - delta, len);
+ } else {
+ FixedArray* elms = FixedArray::cast(elms_obj);
+ DisallowHeapAllocation no_gc;
+ heap->MoveElements(elms, 0, delta, len - delta);
+ FillWithHoles(heap, elms, len - delta, len);
+ }
+ }
elms_changed = true;
} else {
if (elms_obj->IsFixedDoubleArray()) {
Index: src/mark-compact.cc
diff --git a/src/mark-compact.cc b/src/mark-compact.cc
index
b26ca6a016af2588fa700f74966064c82c6ee859..2338095d8d059f1bfb03343d1ec17d7401bf75f1
100644
--- a/src/mark-compact.cc
+++ b/src/mark-compact.cc
@@ -664,6 +664,21 @@ bool
MarkCompactCollector::IsConcurrentSweepingInProgress() {
}
+bool MarkCompactCollector::CanMoveObjectStart(HeapObject* object) {
+ Address address = object->address();
+ bool is_in_old_pointer_space = heap_->InOldPointerSpace(address);
+ bool is_in_old_data_space = heap_->InOldDataSpace(address);
+
+ if (heap_->lo_space()->Contains(object)) return false;
+
+ // We cannot move the object start if the given old space page is
+ // concurrently swept.
+ return (!is_in_old_pointer_space && !is_in_old_data_space) ||
+ Page::FromAddress(address)->parallel_sweeping() <=
+ MemoryChunk::PARALLEL_SWEEPING_FINALIZE;
+ }
+
+
void Marking::TransferMark(Address old_start, Address new_start) {
// This is only used when resizing an object.
ASSERT(MemoryChunk::FromAddress(old_start) ==
@@ -4086,6 +4101,7 @@ void
MarkCompactCollector::SweepInParallel(PagedSpace* space) {
if (p->TryParallelSweeping()) {
SweepConservatively<SWEEP_IN_PARALLEL>(space, &private_free_list, p);
free_list->Concatenate(&private_free_list);
+ p->set_parallel_sweeping(MemoryChunk::PARALLEL_SWEEPING_FINALIZE);
}
}
}
@@ -4284,10 +4300,11 @@ void
MarkCompactCollector::ParallelSweepSpaceComplete(PagedSpace* space) {
PageIterator it(space);
while (it.has_next()) {
Page* p = it.next();
- if (p->parallel_sweeping() ==
MemoryChunk::PARALLEL_SWEEPING_IN_PROGRESS) {
+ if (p->parallel_sweeping() == MemoryChunk::PARALLEL_SWEEPING_FINALIZE)
{
p->set_parallel_sweeping(MemoryChunk::PARALLEL_SWEEPING_DONE);
p->MarkSweptConservatively();
}
+ ASSERT(p->parallel_sweeping() == MemoryChunk::PARALLEL_SWEEPING_DONE);
}
}
Index: src/mark-compact.h
diff --git a/src/mark-compact.h b/src/mark-compact.h
index
0ebe8a0f747846193bfd0002cccd8bec247df4a0..165eab88dcb99c1c1c35dcd3f8702be7e3e3a627
100644
--- a/src/mark-compact.h
+++ b/src/mark-compact.h
@@ -738,6 +738,8 @@ class MarkCompactCollector {
return sequential_sweeping_;
}
+ bool CanMoveObjectStart(HeapObject* object);
+
// Mark the global table which maps weak objects to dependent code
without
// marking its contents.
void MarkWeakObjectToCodeTable();
Index: src/spaces.h
diff --git a/src/spaces.h b/src/spaces.h
index
770b88a9fba85e8ae8c37bee3880a63cf56a6f84..71a7a2b934862edcba7c7c9e0b06b36b8dc312d1
100644
--- a/src/spaces.h
+++ b/src/spaces.h
@@ -475,6 +475,7 @@ class MemoryChunk {
// sweeping must not be performed on that page.
enum ParallelSweepingState {
PARALLEL_SWEEPING_DONE,
+ PARALLEL_SWEEPING_FINALIZE,
PARALLEL_SWEEPING_IN_PROGRESS,
PARALLEL_SWEEPING_PENDING
};
--
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