ab2b18e1be
This CL removes the GetTraceDescriptor virtual call from garbage collected mixins and replaces it with querying the object start bitmap. The CL also removes the mixin macros which are now no longer needed. Bug: chromium:1056170 Change-Id: I27ed299f93025d09a3bb3f0d17b14bed3c200565 Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2287508 Reviewed-by: Michael Lippautz <mlippautz@chromium.org> Reviewed-by: Anton Bikineev <bikineev@chromium.org> Commit-Queue: Omer Katz <omerkatz@chromium.org> Cr-Commit-Position: refs/heads/master@{#68787}
117 lines
3.2 KiB
C++
117 lines
3.2 KiB
C++
// Copyright 2020 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 INCLUDE_CPPGC_GARBAGE_COLLECTED_H_
|
|
#define INCLUDE_CPPGC_GARBAGE_COLLECTED_H_
|
|
|
|
#include <type_traits>
|
|
|
|
#include "cppgc/internal/api-constants.h"
|
|
#include "cppgc/platform.h"
|
|
#include "cppgc/trace-trait.h"
|
|
#include "cppgc/type-traits.h"
|
|
|
|
namespace cppgc {
|
|
|
|
class Visitor;
|
|
|
|
namespace internal {
|
|
|
|
class GarbageCollectedBase {
|
|
public:
|
|
// Must use MakeGarbageCollected.
|
|
void* operator new(size_t) = delete;
|
|
void* operator new[](size_t) = delete;
|
|
// The garbage collector is taking care of reclaiming the object. Also,
|
|
// virtual destructor requires an unambiguous, accessible 'operator delete'.
|
|
void operator delete(void*) {
|
|
#ifdef V8_ENABLE_CHECKS
|
|
internal::Abort();
|
|
#endif // V8_ENABLE_CHECKS
|
|
}
|
|
void operator delete[](void*) = delete;
|
|
|
|
protected:
|
|
GarbageCollectedBase() = default;
|
|
};
|
|
|
|
} // namespace internal
|
|
|
|
/**
|
|
* Base class for managed objects. Only descendent types of GarbageCollected
|
|
* can be constructed using MakeGarbageCollected. Must be inherited from as
|
|
* left-most base class.
|
|
*
|
|
* Types inheriting from GarbageCollected must provide a method of
|
|
* signature `void Trace(cppgc::Visitor*) const` that dispatchs all managed
|
|
* pointers to the visitor and delegates to garbage-collected base classes.
|
|
* The method must be virtual if the type is not directly a child of
|
|
* GarbageCollected and marked as final.
|
|
*
|
|
* \code
|
|
* // Example using final class.
|
|
* class FinalType final : public GarbageCollected<FinalType> {
|
|
* public:
|
|
* void Trace(cppgc::Visitor* visitor) const {
|
|
* // Dispatch using visitor->Trace(...);
|
|
* }
|
|
* };
|
|
*
|
|
* // Example using non-final base class.
|
|
* class NonFinalBase : public GarbageCollected<NonFinalBase> {
|
|
* public:
|
|
* virtual void Trace(cppgc::Visitor*) const {}
|
|
* };
|
|
*
|
|
* class FinalChild final : public NonFinalBase {
|
|
* public:
|
|
* void Trace(cppgc::Visitor* visitor) const final {
|
|
* // Dispatch using visitor->Trace(...);
|
|
* NonFinalBase::Trace(visitor);
|
|
* }
|
|
* };
|
|
* \endcode
|
|
*/
|
|
template <typename>
|
|
class GarbageCollected : public internal::GarbageCollectedBase {
|
|
public:
|
|
using IsGarbageCollectedTypeMarker = void;
|
|
|
|
protected:
|
|
GarbageCollected() = default;
|
|
};
|
|
|
|
/**
|
|
* Base class for managed mixin objects. Such objects cannot be constructed
|
|
* directly but must be mixed into the inheritance hierarchy of a
|
|
* GarbageCollected object.
|
|
*
|
|
* Types inheriting from GarbageCollectedMixin must override a virtual method
|
|
* of signature `void Trace(cppgc::Visitor*) const` that dispatchs all managed
|
|
* pointers to the visitor and delegates to base classes.
|
|
*
|
|
* \code
|
|
* class Mixin : public GarbageCollectedMixin {
|
|
* public:
|
|
* void Trace(cppgc::Visitor* visitor) const override {
|
|
* // Dispatch using visitor->Trace(...);
|
|
* }
|
|
* };
|
|
* \endcode
|
|
*/
|
|
class GarbageCollectedMixin : public internal::GarbageCollectedBase {
|
|
public:
|
|
using IsGarbageCollectedMixinTypeMarker = void;
|
|
|
|
/**
|
|
* This Trace method must be overriden by objects inheriting from
|
|
* GarbageCollectedMixin.
|
|
*/
|
|
virtual void Trace(cppgc::Visitor*) const {}
|
|
};
|
|
|
|
} // namespace cppgc
|
|
|
|
#endif // INCLUDE_CPPGC_GARBAGE_COLLECTED_H_
|