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// Copyright 2011 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef V8_HEAP_SPACES_INL_H_
#define V8_HEAP_SPACES_INL_H_
#include "src/common/globals.h"
#include "src/heap/spaces.h"
#include "src/base/atomic-utils.h"
#include "src/base/bounded-page-allocator.h"
#include "src/base/v8-fallthrough.h"
#include "src/heap/heap-inl.h"
#include "src/heap/incremental-marking.h"
#include "src/objects/code-inl.h"
#include "src/sanitizer/msan.h"
namespace v8 {
namespace internal {
template <class PAGE_TYPE>
PageIteratorImpl<PAGE_TYPE>& PageIteratorImpl<PAGE_TYPE>::operator++() {
p_ = p_->next_page();
return *this;
}
template <class PAGE_TYPE>
PageIteratorImpl<PAGE_TYPE> PageIteratorImpl<PAGE_TYPE>::operator++(int) {
PageIteratorImpl<PAGE_TYPE> tmp(*this);
operator++();
return tmp;
}
PageRange::PageRange(Address start, Address limit)
: begin_(Page::FromAddress(start)),
end_(Page::FromAllocationAreaAddress(limit)->next_page()) {
#ifdef DEBUG
if (begin_->InNewSpace()) {
SemiSpace::AssertValidRange(start, limit);
}
#endif // DEBUG
}
// -----------------------------------------------------------------------------
// SemiSpaceObjectIterator
HeapObject SemiSpaceObjectIterator::Next() {
while (current_ != limit_) {
if (Page::IsAlignedToPageSize(current_)) {
Page* page = Page::FromAllocationAreaAddress(current_);
page = page->next_page();
DCHECK(page);
current_ = page->area_start();
if (current_ == limit_) return HeapObject();
}
HeapObject object = HeapObject::FromAddress(current_);
current_ += object.Size();
if (!object.IsFreeSpaceOrFiller()) {
return object;
}
}
return HeapObject();
}
// -----------------------------------------------------------------------------
// PagedSpaceObjectIterator
HeapObject PagedSpaceObjectIterator::Next() {
do {
HeapObject next_obj = FromCurrentPage();
if (!next_obj.is_null()) return next_obj;
} while (AdvanceToNextPage());
return HeapObject();
}
HeapObject PagedSpaceObjectIterator::FromCurrentPage() {
while (cur_addr_ != cur_end_) {
if (cur_addr_ == space_->top() && cur_addr_ != space_->limit()) {
cur_addr_ = space_->limit();
continue;
}
HeapObject obj = HeapObject::FromAddress(cur_addr_);
const int obj_size = obj.Size();
cur_addr_ += obj_size;
DCHECK_LE(cur_addr_, cur_end_);
if (!obj.IsFreeSpaceOrFiller()) {
if (obj.IsCode()) {
DCHECK_IMPLIES(
space_->identity() != CODE_SPACE,
space_->identity() == RO_SPACE && Code::cast(obj).is_builtin());
DCHECK_CODEOBJECT_SIZE(obj_size, space_);
} else {
DCHECK_OBJECT_SIZE(obj_size);
}
return obj;
}
}
return HeapObject();
}
void Space::IncrementExternalBackingStoreBytes(ExternalBackingStoreType type,
size_t amount) {
base::CheckedIncrement(&external_backing_store_bytes_[type], amount);
heap()->IncrementExternalBackingStoreBytes(type, amount);
}
void Space::DecrementExternalBackingStoreBytes(ExternalBackingStoreType type,
size_t amount) {
base::CheckedDecrement(&external_backing_store_bytes_[type], amount);
heap()->DecrementExternalBackingStoreBytes(type, amount);
}
void Space::MoveExternalBackingStoreBytes(ExternalBackingStoreType type,
Space* from, Space* to,
size_t amount) {
if (from == to) return;
base::CheckedDecrement(&(from->external_backing_store_bytes_[type]), amount);
base::CheckedIncrement(&(to->external_backing_store_bytes_[type]), amount);
}
// -----------------------------------------------------------------------------
// SemiSpace
bool SemiSpace::Contains(HeapObject o) {
MemoryChunk* memory_chunk = MemoryChunk::FromHeapObject(o);
if (memory_chunk->IsLargePage()) return false;
return id_ == kToSpace ? memory_chunk->IsToPage()
: memory_chunk->IsFromPage();
}
bool SemiSpace::Contains(Object o) {
return o.IsHeapObject() && Contains(HeapObject::cast(o));
}
bool SemiSpace::ContainsSlow(Address a) {
for (Page* p : *this) {
if (p == MemoryChunk::FromAddress(a)) return true;
}
return false;
}
// --------------------------------------------------------------------------
// NewSpace
bool NewSpace::Contains(Object o) {
return o.IsHeapObject() && Contains(HeapObject::cast(o));
}
bool NewSpace::Contains(HeapObject o) {
return MemoryChunk::FromHeapObject(o)->InNewSpace();
}
bool NewSpace::ContainsSlow(Address a) {
return from_space_.ContainsSlow(a) || to_space_.ContainsSlow(a);
}
bool NewSpace::ToSpaceContainsSlow(Address a) {
return to_space_.ContainsSlow(a);
}
bool NewSpace::ToSpaceContains(Object o) { return to_space_.Contains(o); }
bool NewSpace::FromSpaceContains(Object o) { return from_space_.Contains(o); }
bool PagedSpace::Contains(Address addr) {
if (V8_ENABLE_THIRD_PARTY_HEAP_BOOL) {
return true;
}
return Page::FromAddress(addr)->owner() == this;
}
bool PagedSpace::Contains(Object o) {
if (!o.IsHeapObject()) return false;
return Page::FromAddress(o.ptr())->owner() == this;
}
void PagedSpace::UnlinkFreeListCategories(Page* page) {
DCHECK_EQ(this, page->owner());
page->ForAllFreeListCategories([this](FreeListCategory* category) {
free_list()->RemoveCategory(category);
});
}
size_t PagedSpace::RelinkFreeListCategories(Page* page) {
DCHECK_EQ(this, page->owner());
size_t added = 0;
page->ForAllFreeListCategories([this, &added](FreeListCategory* category) {
added += category->available();
category->Relink(free_list());
});
DCHECK_IMPLIES(!page->IsFlagSet(Page::NEVER_ALLOCATE_ON_PAGE),
page->AvailableInFreeList() ==
page->AvailableInFreeListFromAllocatedBytes());
return added;
}
bool PagedSpace::TryFreeLast(HeapObject object, int object_size) {
if (allocation_info_.top() != kNullAddress) {
const Address object_address = object.address();
if ((allocation_info_.top() - object_size) == object_address) {
allocation_info_.set_top(object_address);
return true;
}
}
return false;
}
void MemoryChunk::IncrementExternalBackingStoreBytes(
ExternalBackingStoreType type, size_t amount) {
#ifndef V8_ENABLE_THIRD_PARTY_HEAP
base::CheckedIncrement(&external_backing_store_bytes_[type], amount);
owner()->IncrementExternalBackingStoreBytes(type, amount);
#endif
}
void MemoryChunk::DecrementExternalBackingStoreBytes(
ExternalBackingStoreType type, size_t amount) {
#ifndef V8_ENABLE_THIRD_PARTY_HEAP
base::CheckedDecrement(&external_backing_store_bytes_[type], amount);
owner()->DecrementExternalBackingStoreBytes(type, amount);
#endif
}
void MemoryChunk::MoveExternalBackingStoreBytes(ExternalBackingStoreType type,
MemoryChunk* from,
MemoryChunk* to,
size_t amount) {
DCHECK_NOT_NULL(from->owner());
DCHECK_NOT_NULL(to->owner());
base::CheckedDecrement(&(from->external_backing_store_bytes_[type]), amount);
base::CheckedIncrement(&(to->external_backing_store_bytes_[type]), amount);
Space::MoveExternalBackingStoreBytes(type, from->owner(), to->owner(),
amount);
}
AllocationSpace MemoryChunk::owner_identity() const {
if (InReadOnlySpace()) return RO_SPACE;
return owner()->identity();
}
void Page::MarkNeverAllocateForTesting() {
DCHECK(this->owner_identity() != NEW_SPACE);
DCHECK(!IsFlagSet(NEVER_ALLOCATE_ON_PAGE));
SetFlag(NEVER_ALLOCATE_ON_PAGE);
SetFlag(NEVER_EVACUATE);
reinterpret_cast<PagedSpace*>(owner())->free_list()->EvictFreeListItems(this);
}
void Page::MarkEvacuationCandidate() {
DCHECK(!IsFlagSet(NEVER_EVACUATE));
DCHECK_NULL(slot_set<OLD_TO_OLD>());
DCHECK_NULL(typed_slot_set<OLD_TO_OLD>());
SetFlag(EVACUATION_CANDIDATE);
reinterpret_cast<PagedSpace*>(owner())->free_list()->EvictFreeListItems(this);
}
void Page::ClearEvacuationCandidate() {
if (!IsFlagSet(COMPACTION_WAS_ABORTED)) {
DCHECK_NULL(slot_set<OLD_TO_OLD>());
DCHECK_NULL(typed_slot_set<OLD_TO_OLD>());
}
ClearFlag(EVACUATION_CANDIDATE);
InitializeFreeListCategories();
}
HeapObject LargePage::GetObject() {
return HeapObject::FromAddress(area_start());
}
OldGenerationMemoryChunkIterator::OldGenerationMemoryChunkIterator(Heap* heap)
: heap_(heap),
state_(kOldSpaceState),
old_iterator_(heap->old_space()->begin()),
code_iterator_(heap->code_space()->begin()),
map_iterator_(heap->map_space()->begin()),
lo_iterator_(heap->lo_space()->begin()),
code_lo_iterator_(heap->code_lo_space()->begin()) {}
MemoryChunk* OldGenerationMemoryChunkIterator::next() {
switch (state_) {
case kOldSpaceState: {
if (old_iterator_ != heap_->old_space()->end()) return *(old_iterator_++);
state_ = kMapState;
V8_FALLTHROUGH;
}
case kMapState: {
if (map_iterator_ != heap_->map_space()->end()) return *(map_iterator_++);
state_ = kCodeState;
V8_FALLTHROUGH;
}
case kCodeState: {
if (code_iterator_ != heap_->code_space()->end())
return *(code_iterator_++);
state_ = kLargeObjectState;
V8_FALLTHROUGH;
}
case kLargeObjectState: {
if (lo_iterator_ != heap_->lo_space()->end()) return *(lo_iterator_++);
state_ = kCodeLargeObjectState;
V8_FALLTHROUGH;
}
case kCodeLargeObjectState: {
if (code_lo_iterator_ != heap_->code_lo_space()->end())
return *(code_lo_iterator_++);
state_ = kFinishedState;
V8_FALLTHROUGH;
}
case kFinishedState:
return nullptr;
default:
break;
}
UNREACHABLE();
}
bool FreeListCategory::is_linked(FreeList* owner) const {
return prev_ != nullptr || next_ != nullptr ||
owner->categories_[type_] == this;
}
void FreeListCategory::UpdateCountersAfterAllocation(size_t allocation_size) {
available_ -= allocation_size;
}
Page* FreeList::GetPageForCategoryType(FreeListCategoryType type) {
FreeListCategory* category_top = top(type);
if (category_top != nullptr) {
DCHECK(!category_top->top().is_null());
return Page::FromHeapObject(category_top->top());
} else {
return nullptr;
}
}
Page* FreeListLegacy::GetPageForSize(size_t size_in_bytes) {
const int minimum_category =
static_cast<int>(SelectFreeListCategoryType(size_in_bytes));
Page* page = GetPageForCategoryType(kHuge);
if (!page && static_cast<int>(kLarge) >= minimum_category)
page = GetPageForCategoryType(kLarge);
if (!page && static_cast<int>(kMedium) >= minimum_category)
page = GetPageForCategoryType(kMedium);
if (!page && static_cast<int>(kSmall) >= minimum_category)
page = GetPageForCategoryType(kSmall);
if (!page && static_cast<int>(kTiny) >= minimum_category)
page = GetPageForCategoryType(kTiny);
if (!page && static_cast<int>(kTiniest) >= minimum_category)
page = GetPageForCategoryType(kTiniest);
return page;
}
Page* FreeListFastAlloc::GetPageForSize(size_t size_in_bytes) {
const int minimum_category =
static_cast<int>(SelectFreeListCategoryType(size_in_bytes));
Page* page = GetPageForCategoryType(kHuge);
if (!page && static_cast<int>(kLarge) >= minimum_category)
page = GetPageForCategoryType(kLarge);
if (!page && static_cast<int>(kMedium) >= minimum_category)
page = GetPageForCategoryType(kMedium);
return page;
}
AllocationResult LocalAllocationBuffer::AllocateRawAligned(
int size_in_bytes, AllocationAlignment alignment) {
Address current_top = allocation_info_.top();
int filler_size = Heap::GetFillToAlign(current_top, alignment);
Address new_top = current_top + filler_size + size_in_bytes;
if (new_top > allocation_info_.limit()) return AllocationResult::Retry();
allocation_info_.set_top(new_top);
if (filler_size > 0) {
return heap_->PrecedeWithFiller(HeapObject::FromAddress(current_top),
filler_size);
}
return AllocationResult(HeapObject::FromAddress(current_top));
}
bool PagedSpace::EnsureLinearAllocationArea(int size_in_bytes,
AllocationOrigin origin) {
if (allocation_info_.top() + size_in_bytes <= allocation_info_.limit()) {
return true;
}
return SlowRefillLinearAllocationArea(size_in_bytes, origin);
}
HeapObject PagedSpace::AllocateLinearly(int size_in_bytes) {
Address current_top = allocation_info_.top();
Address new_top = current_top + size_in_bytes;
DCHECK_LE(new_top, allocation_info_.limit());
allocation_info_.set_top(new_top);
return HeapObject::FromAddress(current_top);
}
HeapObject PagedSpace::TryAllocateLinearlyAligned(
int* size_in_bytes, AllocationAlignment alignment) {
Address current_top = allocation_info_.top();
int filler_size = Heap::GetFillToAlign(current_top, alignment);
Address new_top = current_top + filler_size + *size_in_bytes;
if (new_top > allocation_info_.limit()) return HeapObject();
allocation_info_.set_top(new_top);
if (filler_size > 0) {
*size_in_bytes += filler_size;
return heap()->PrecedeWithFiller(HeapObject::FromAddress(current_top),
filler_size);
}
return HeapObject::FromAddress(current_top);
}
AllocationResult PagedSpace::AllocateRawUnaligned(int size_in_bytes,
AllocationOrigin origin) {
DCHECK_IMPLIES(identity() == RO_SPACE, !IsDetached());
if (!EnsureLinearAllocationArea(size_in_bytes, origin)) {
return AllocationResult::Retry(identity());
}
HeapObject object = AllocateLinearly(size_in_bytes);
DCHECK(!object.is_null());
MSAN_ALLOCATED_UNINITIALIZED_MEMORY(object.address(), size_in_bytes);
if (FLAG_trace_allocations_origins) {
UpdateAllocationOrigins(origin);
}
return object;
}
AllocationResult PagedSpace::AllocateRawAligned(int size_in_bytes,
AllocationAlignment alignment,
AllocationOrigin origin) {
DCHECK(identity() == OLD_SPACE || identity() == RO_SPACE);
DCHECK_IMPLIES(identity() == RO_SPACE, !IsDetached());
int allocation_size = size_in_bytes;
HeapObject object = TryAllocateLinearlyAligned(&allocation_size, alignment);
if (object.is_null()) {
// We don't know exactly how much filler we need to align until space is
// allocated, so assume the worst case.
int filler_size = Heap::GetMaximumFillToAlign(alignment);
allocation_size += filler_size;
if (!EnsureLinearAllocationArea(allocation_size, origin)) {
return AllocationResult::Retry(identity());
}
allocation_size = size_in_bytes;
object = TryAllocateLinearlyAligned(&allocation_size, alignment);
DCHECK(!object.is_null());
}
MSAN_ALLOCATED_UNINITIALIZED_MEMORY(object.address(), size_in_bytes);
if (FLAG_trace_allocations_origins) {
UpdateAllocationOrigins(origin);
}
return object;
}
AllocationResult PagedSpace::AllocateRaw(int size_in_bytes,
AllocationAlignment alignment,
AllocationOrigin origin) {
if (top_on_previous_step_ && top() < top_on_previous_step_ &&
SupportsInlineAllocation()) {
// Generated code decreased the top() pointer to do folded allocations.
// The top_on_previous_step_ can be one byte beyond the current page.
DCHECK_NE(top(), kNullAddress);
DCHECK_EQ(Page::FromAllocationAreaAddress(top()),
Page::FromAllocationAreaAddress(top_on_previous_step_ - 1));
top_on_previous_step_ = top();
}
size_t bytes_since_last =
top_on_previous_step_ ? top() - top_on_previous_step_ : 0;
DCHECK_IMPLIES(!SupportsInlineAllocation(), bytes_since_last == 0);
#ifdef V8_HOST_ARCH_32_BIT
AllocationResult result =
alignment != kWordAligned
? AllocateRawAligned(size_in_bytes, alignment, origin)
: AllocateRawUnaligned(size_in_bytes, origin);
#else
AllocationResult result = AllocateRawUnaligned(size_in_bytes, origin);
#endif
HeapObject heap_obj;
if (!result.IsRetry() && result.To(&heap_obj) && !is_local_space()) {
AllocationStep(static_cast<int>(size_in_bytes + bytes_since_last),
heap_obj.address(), size_in_bytes);
StartNextInlineAllocationStep();
DCHECK_IMPLIES(
heap()->incremental_marking()->black_allocation(),
heap()->incremental_marking()->marking_state()->IsBlack(heap_obj));
}
return result;
}
// -----------------------------------------------------------------------------
// NewSpace
AllocationResult NewSpace::AllocateRawAligned(int size_in_bytes,
AllocationAlignment alignment,
AllocationOrigin origin) {
Address top = allocation_info_.top();
int filler_size = Heap::GetFillToAlign(top, alignment);
int aligned_size_in_bytes = size_in_bytes + filler_size;
if (allocation_info_.limit() - top <
static_cast<uintptr_t>(aligned_size_in_bytes)) {
// See if we can create room.
if (!EnsureAllocation(size_in_bytes, alignment)) {
return AllocationResult::Retry();
}
top = allocation_info_.top();
filler_size = Heap::GetFillToAlign(top, alignment);
aligned_size_in_bytes = size_in_bytes + filler_size;
}
HeapObject obj = HeapObject::FromAddress(top);
allocation_info_.set_top(top + aligned_size_in_bytes);
DCHECK_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
if (filler_size > 0) {
obj = heap()->PrecedeWithFiller(obj, filler_size);
}
MSAN_ALLOCATED_UNINITIALIZED_MEMORY(obj.address(), size_in_bytes);
if (FLAG_trace_allocations_origins) {
UpdateAllocationOrigins(origin);
}
return obj;
}
AllocationResult NewSpace::AllocateRawUnaligned(int size_in_bytes,
AllocationOrigin origin) {
Address top = allocation_info_.top();
if (allocation_info_.limit() < top + size_in_bytes) {
// See if we can create room.
if (!EnsureAllocation(size_in_bytes, kWordAligned)) {
return AllocationResult::Retry();
}
top = allocation_info_.top();
}
HeapObject obj = HeapObject::FromAddress(top);
allocation_info_.set_top(top + size_in_bytes);
DCHECK_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
MSAN_ALLOCATED_UNINITIALIZED_MEMORY(obj.address(), size_in_bytes);
if (FLAG_trace_allocations_origins) {
UpdateAllocationOrigins(origin);
}
return obj;
}
AllocationResult NewSpace::AllocateRaw(int size_in_bytes,
AllocationAlignment alignment,
AllocationOrigin origin) {
if (top() < top_on_previous_step_) {
// Generated code decreased the top() pointer to do folded allocations
DCHECK_EQ(Page::FromAllocationAreaAddress(top()),
Page::FromAllocationAreaAddress(top_on_previous_step_));
top_on_previous_step_ = top();
}
#ifdef V8_HOST_ARCH_32_BIT
return alignment != kWordAligned
? AllocateRawAligned(size_in_bytes, alignment, origin)
: AllocateRawUnaligned(size_in_bytes, origin);
#else
#ifdef V8_COMPRESS_POINTERS
// TODO(ishell, v8:8875): Consider using aligned allocations once the
// allocation alignment inconsistency is fixed. For now we keep using
// unaligned access since both x64 and arm64 architectures (where pointer
// compression is supported) allow unaligned access to doubles and full words.
#endif // V8_COMPRESS_POINTERS
return AllocateRawUnaligned(size_in_bytes, origin);
#endif
}
V8_WARN_UNUSED_RESULT inline AllocationResult NewSpace::AllocateRawSynchronized(
int size_in_bytes, AllocationAlignment alignment, AllocationOrigin origin) {
base::MutexGuard guard(&mutex_);
return AllocateRaw(size_in_bytes, alignment, origin);
}
LocalAllocationBuffer LocalAllocationBuffer::FromResult(Heap* heap,
AllocationResult result,
intptr_t size) {
if (result.IsRetry()) return InvalidBuffer();
HeapObject obj;
bool ok = result.To(&obj);
USE(ok);
DCHECK(ok);
Address top = HeapObject::cast(obj).address();
return LocalAllocationBuffer(heap, LinearAllocationArea(top, top + size));
}
bool LocalAllocationBuffer::TryMerge(LocalAllocationBuffer* other) {
if (allocation_info_.top() == other->allocation_info_.limit()) {
allocation_info_.set_top(other->allocation_info_.top());
other->allocation_info_.Reset(kNullAddress, kNullAddress);
return true;
}
return false;
}
bool LocalAllocationBuffer::TryFreeLast(HeapObject object, int object_size) {
if (IsValid()) {
const Address object_address = object.address();
if ((allocation_info_.top() - object_size) == object_address) {
allocation_info_.set_top(object_address);
return true;
}
}
return false;
}
} // namespace internal
} // namespace v8
#endif // V8_HEAP_SPACES_INL_H_
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