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[heap] Fix Heap::EnsureFillerObjectAtTop for non-contiguous new space

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R=hpayer@chromium.org
BUG=chromium:601014, chromium:601329, chromium:581412
LOG=N

Review URL: https://codereview.chromium.org/1862263003

Cr-Commit-Position: refs/heads/master@{#35327}
This commit is contained in:
mlippautz 2016-04-07 01:54:06 -07:00 committed by Commit bot
parent 51d3932580
commit 165186f272
1 changed files with 9 additions and 15 deletions
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24
src/heap/heap.cc
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@ -943,21 +943,15 @@ void Heap::ReportExternalMemoryPressure(const char* gc_reason) {
void Heap::EnsureFillerObjectAtTop() {
// There may be an allocation memento behind every object in new space.
// If we evacuate a not full new space or if we are on the last page of
// the new space, then there may be uninitialized memory behind the top
// pointer of the new space page. We store a filler object there to
// identify the unused space.
Address from_top = new_space_.top();
// Check that from_top is inside its page (i.e., not at the end).
Address space_end = new_space_.ToSpaceEnd();
if (from_top < space_end) {
Page* page = Page::FromAddress(from_top);
if (page->Contains(from_top)) {
int remaining_in_page = static_cast<int>(page->area_end() - from_top);
CreateFillerObjectAt(from_top, remaining_in_page,
ClearRecordedSlots::kNo);
}
// There may be an allocation memento behind objects in new space. Upon
// evacuation of a non-full new space (or if we are on the last page) there
// may be uninitialized memory behind top. We fill the remainder of the page
// with a filler.
Address to_top = new_space_.top();
NewSpacePage* page = NewSpacePage::FromAddress(to_top - kPointerSize);
if (page->Contains(to_top)) {
int remaining_in_page = static_cast<int>(page->area_end() - to_top);
CreateFillerObjectAt(to_top, remaining_in_page, ClearRecordedSlots::kNo);
}
}