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// Copyright 2021 The Chromium 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 THIRD_PARTY_BLINK_RENDERER_PLATFORM_HEAP_HEAP_ALLOCATOR_IMPL_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_HEAP_HEAP_ALLOCATOR_IMPL_H_
#include "third_party/blink/renderer/platform/heap/collection_support/heap_hash_table_backing.h"
#include "third_party/blink/renderer/platform/heap/collection_support/heap_vector_backing.h"
#include "third_party/blink/renderer/platform/heap/garbage_collected.h"
#include "third_party/blink/renderer/platform/heap/thread_state_storage.h"
#include "third_party/blink/renderer/platform/heap/visitor.h"
#include "third_party/blink/renderer/platform/heap/write_barrier.h"
#include "third_party/blink/renderer/platform/platform_export.h"
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
#include "v8/include/cppgc/explicit-management.h"
#include "v8/include/cppgc/heap-consistency.h"
#include "v8/include/cppgc/trace-trait.h"
#include "v8/include/cppgc/visitor.h"
namespace blink {
class PLATFORM_EXPORT HeapAllocator {
STATIC_ONLY(HeapAllocator);
public:
using HeapConsistency = cppgc::subtle::HeapConsistency;
using LivenessBroker = blink::LivenessBroker;
using TraceCallback = cppgc::TraceCallback;
using WeakCallback = cppgc::WeakCallback;
static constexpr bool kIsGarbageCollected = true;
// See wtf/size_t.h for details.
static constexpr size_t kMaxHeapObjectSizeLog2 = 27;
static constexpr size_t kMaxHeapObjectSize = 1 << kMaxHeapObjectSizeLog2;
template <typename T>
static size_t MaxElementCountInBackingStore() {
return kMaxHeapObjectSize / sizeof(T);
}
template <typename T>
static size_t QuantizedSize(size_t count) {
CHECK_LE(count, MaxElementCountInBackingStore<T>());
// Oilpan's internal size is independent of MaxElementCountInBackingStore()
// and the required size to match capacity needs.
return count * sizeof(T);
}
template <typename T>
static T* AllocateVectorBacking(size_t size) {
return HeapVectorBacking<T>::ToArray(
MakeGarbageCollected<HeapVectorBacking<T>>(size / sizeof(T)));
}
template <typename T>
static void FreeVectorBacking(T* array) {
if (!array)
return;
HeapVectorBacking<T>::FromArray(array)->Free(
ThreadStateStorageFor<ThreadingTrait<T>::kAffinity>::GetState()
->heap_handle());
}
template <typename T>
static bool ExpandVectorBacking(T* array, size_t new_size) {
DCHECK(array);
return HeapVectorBacking<T>::FromArray(array)->Resize(new_size);
}
template <typename T>
static bool ShrinkVectorBacking(T* array, size_t, size_t new_size) {
DCHECK(array);
return HeapVectorBacking<T>::FromArray(array)->Resize(new_size);
}
template <typename T, typename HashTable>
static T* AllocateHashTableBacking(size_t size) {
static_assert(sizeof(T) == sizeof(typename HashTable::ValueType),
"T must match ValueType.");
return HeapHashTableBacking<HashTable>::ToArray(
MakeGarbageCollected<HeapHashTableBacking<HashTable>>(size /
sizeof(T)));
}
template <typename T, typename HashTable>
static T* AllocateZeroedHashTableBacking(size_t size) {
return AllocateHashTableBacking<T, HashTable>(size);
}
template <typename T, typename HashTable>
static void FreeHashTableBacking(T* array) {
if (!array)
return;
HeapHashTableBacking<HashTable>::FromArray(array)->Free(
ThreadStateStorageFor<ThreadingTrait<
HeapHashTableBacking<HashTable>>::kAffinity>::GetState()
->heap_handle());
}
template <typename T, typename HashTable>
static bool ExpandHashTableBacking(T* array, size_t new_size) {
DCHECK(array);
return HeapHashTableBacking<HashTable>::FromArray(array)->Resize(new_size);
}
static bool IsAllocationAllowed() {
return cppgc::subtle::DisallowGarbageCollectionScope::
IsGarbageCollectionAllowed(
ThreadStateStorage::Current()->heap_handle());
}
static bool IsIncrementalMarking() {
auto& heap_handle = ThreadStateStorage::Current()->heap_handle();
return cppgc::subtle::HeapState::IsMarking(heap_handle) &&
!cppgc::subtle::HeapState::IsInAtomicPause(heap_handle);
}
static void EnterGCForbiddenScope() {
cppgc::subtle::NoGarbageCollectionScope::Enter(
ThreadStateStorage::Current()->heap_handle());
}
static void LeaveGCForbiddenScope() {
cppgc::subtle::NoGarbageCollectionScope::Leave(
ThreadStateStorage::Current()->heap_handle());
}
template <typename Traits>
static bool CanReuseHashTableDeletedBucket() {
if (Traits::kEmptyValueIsZero || !Traits::kCanTraceConcurrently)
return true;
return !IsIncrementalMarking();
}
template <typename T>
static void BackingWriteBarrier(T** slot) {
WriteBarrier::DispatchForObject(slot);
}
template <typename T>
static void TraceBackingStoreIfMarked(T* object) {
HeapConsistency::WriteBarrierParams params;
if (HeapConsistency::GetWriteBarrierType(object, params) ==
HeapConsistency::WriteBarrierType::kMarking) {
HeapConsistency::SteeleWriteBarrier(params, object);
}
}
template <typename T, typename Traits>
static void NotifyNewObject(T* slot_in_backing) {
HeapConsistency::WriteBarrierParams params;
// `slot_in_backing` points into a backing store and T is not necessarily a
// garbage collected type but may be kept inline.
switch (HeapConsistency::GetWriteBarrierType(
slot_in_backing, params, []() -> cppgc::HeapHandle& {
return ThreadStateStorageFor<ThreadingTrait<T>::kAffinity>::GetState()
->heap_handle();
})) {
case HeapConsistency::WriteBarrierType::kMarking:
HeapConsistency::DijkstraWriteBarrierRange(
params, slot_in_backing, sizeof(T), 1,
TraceCollectionIfEnabled<WTF::kNoWeakHandling, T, Traits>::Trace);
break;
case HeapConsistency::WriteBarrierType::kGenerational:
HeapConsistency::GenerationalBarrier(params, slot_in_backing);
break;
case HeapConsistency::WriteBarrierType::kNone:
break;
default:
break; // TODO(1056170): Remove default case when API is stable.
}
}
template <typename T, typename Traits>
static void NotifyNewObjects(T* first_element, size_t length) {
HeapConsistency::WriteBarrierParams params;
// `first_element` points into a backing store and T is not necessarily a
// garbage collected type but may be kept inline.
switch (HeapConsistency::GetWriteBarrierType(
first_element, params, []() -> cppgc::HeapHandle& {
return ThreadStateStorageFor<ThreadingTrait<T>::kAffinity>::GetState()
->heap_handle();
})) {
case HeapConsistency::WriteBarrierType::kMarking:
HeapConsistency::DijkstraWriteBarrierRange(
params, first_element, sizeof(T), length,
TraceCollectionIfEnabled<WTF::kNoWeakHandling, T, Traits>::Trace);
break;
case HeapConsistency::WriteBarrierType::kGenerational:
HeapConsistency::GenerationalBarrier(params, first_element);
break;
case HeapConsistency::WriteBarrierType::kNone:
break;
default:
break; // TODO(1056170): Remove default case when API is stable.
}
}
template <typename T, typename Traits>
static void Trace(Visitor* visitor, const T& t) {
TraceCollectionIfEnabled<WTF::WeakHandlingTrait<T>::value, T,
Traits>::Trace(visitor, &t);
}
template <typename T>
static void TraceVectorBacking(Visitor* visitor,
const T* backing,
const T* const* backing_slot) {
visitor->RegisterMovableReference(const_cast<const HeapVectorBacking<T>**>(
reinterpret_cast<const HeapVectorBacking<T>* const*>(backing_slot)));
visitor->Trace(reinterpret_cast<const HeapVectorBacking<T>*>(backing));
}
template <typename T, typename HashTable>
static void TraceHashTableBackingStrongly(Visitor* visitor,
const T* backing,
const T* const* backing_slot) {
visitor->RegisterMovableReference(
const_cast<const HeapHashTableBacking<HashTable>**>(
reinterpret_cast<const HeapHashTableBacking<HashTable>* const*>(
backing_slot)));
visitor->Trace(
reinterpret_cast<const HeapHashTableBacking<HashTable>*>(backing));
}
template <typename T, typename HashTable>
static void TraceHashTableBackingWeakly(Visitor* visitor,
const T* backing,
const T* const* backing_slot,
WeakCallback callback,
const void* parameter) {
visitor->RegisterMovableReference(
const_cast<const HeapHashTableBacking<HashTable>**>(
reinterpret_cast<const HeapHashTableBacking<HashTable>* const*>(
backing_slot)));
visitor->TraceWeakContainer(
reinterpret_cast<const HeapHashTableBacking<HashTable>*>(backing),
callback, parameter);
}
static bool DeferTraceToMutatorThreadIfConcurrent(Visitor* visitor,
const void* object,
TraceCallback callback,
size_t deferred_size) {
return visitor->DeferTraceToMutatorThreadIfConcurrent(object, callback,
deferred_size);
}
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_HEAP_HEAP_ALLOCATOR_IMPL_H_
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