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[CSA] Eliminate write barriers for young generation large objects in CodeStubAssembler::ExtractToFixedArray.

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Bug: v8:8945
Change-Id: Ib86ed35de107d5e658dbeaaca68d9a1cb8b0f309
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1515754
Commit-Queue: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60215}
This commit is contained in:
Hannes Payer 2019-03-13 15:10:51 +01:00 committed by Commit Bot
parent a6ccce9efb
commit ac71974744
1 changed files with 32 additions and 16 deletions
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48
src/code-stub-assembler.cc
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@ -4172,18 +4172,20 @@ TNode<FixedArray> CodeStubAssembler::ExtractToFixedArray(
BIND(&new_space_check);
{
bool handle_old_space = true;
if (extract_flags & ExtractFixedArrayFlag::kNewSpaceAllocationOnly) {
handle_old_space = false;
CSA_ASSERT(this, Word32BinaryNot(FixedArraySizeDoesntFitInNewSpace(
count, FixedArray::kHeaderSize, parameter_mode)));
} else {
int constant_count;
handle_old_space =
!TryGetIntPtrOrSmiConstantValue(count, &constant_count,
parameter_mode) ||
(constant_count >
FixedArray::GetMaxLengthForNewSpaceAllocation(PACKED_ELEMENTS));
bool handle_old_space = !FLAG_young_generation_large_objects;
if (handle_old_space) {
if (extract_flags & ExtractFixedArrayFlag::kNewSpaceAllocationOnly) {
handle_old_space = false;
CSA_ASSERT(this, Word32BinaryNot(FixedArraySizeDoesntFitInNewSpace(
count, FixedArray::kHeaderSize, parameter_mode)));
} else {
int constant_count;
handle_old_space =
!TryGetIntPtrOrSmiConstantValue(count, &constant_count,
parameter_mode) ||
(constant_count >
FixedArray::GetMaxLengthForNewSpaceAllocation(PACKED_ELEMENTS));
}
}
Label old_space(this, Label::kDeferred);
@ -4192,15 +4194,29 @@ TNode<FixedArray> CodeStubAssembler::ExtractToFixedArray(
capacity, &old_space, FixedArray::kHeaderSize, parameter_mode);
}
Comment("Copy FixedArray new space");
Comment("Copy FixedArray in young generation");
// We use PACKED_ELEMENTS to tell AllocateFixedArray and
// CopyFixedArrayElements that we want a FixedArray.
const ElementsKind to_kind = PACKED_ELEMENTS;
TNode<FixedArrayBase> to_elements =
AllocateFixedArray(to_kind, capacity, parameter_mode,
AllocationFlag::kNone, var_target_map.value());
AllocateFixedArray(to_kind, capacity, parameter_mode, allocation_flags,
var_target_map.value());
var_result.Bind(to_elements);
#ifdef DEBUG
TNode<IntPtrT> object_word = BitcastTaggedToWord(to_elements);
TNode<IntPtrT> object_page = PageFromAddress(object_word);
TNode<IntPtrT> page_flags =
UncheckedCast<IntPtrT>(Load(MachineType::IntPtr(), object_page,
IntPtrConstant(Page::kFlagsOffset)));
CSA_ASSERT(
this,
WordNotEqual(
WordAnd(page_flags,
IntPtrConstant(MemoryChunk::kIsInYoungGenerationMask)),
IntPtrConstant(0)));
#endif
if (convert_holes == HoleConversionMode::kDontConvert &&
!IsDoubleElementsKind(from_kind)) {
// We can use CopyElements (memcpy) because we don't need to replace or
@ -4223,7 +4239,7 @@ TNode<FixedArray> CodeStubAssembler::ExtractToFixedArray(
if (handle_old_space) {
BIND(&old_space);
{
Comment("Copy FixedArray old space");
Comment("Copy FixedArray in old generation");
Label copy_one_by_one(this);
// Try to use memcpy if we don't need to convert holes to undefined.