0505419a1e
Introduce RootVisitor and related class hierarchy to just handle roots. This avoids the awkard definitions for roots visiation in all the cases they are not needed. Change-Id: Ib0912e4bf543db2ecf68caead6929c68d6afdda6 Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3782794 Reviewed-by: Omer Katz <omerkatz@chromium.org> Reviewed-by: Anton Bikineev <bikineev@chromium.org> Commit-Queue: Michael Lippautz <mlippautz@chromium.org> Cr-Commit-Position: refs/heads/main@{#82107}
121 lines
3.1 KiB
C++
121 lines
3.1 KiB
C++
// Copyright 2020 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef INCLUDE_CPPGC_TRACE_TRAIT_H_
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#define INCLUDE_CPPGC_TRACE_TRAIT_H_
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#include <type_traits>
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#include "cppgc/type-traits.h"
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#include "v8config.h" // NOLINT(build/include_directory)
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namespace cppgc {
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class Visitor;
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namespace internal {
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class RootVisitor;
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using TraceRootCallback = void (*)(RootVisitor&, const void* object);
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// Implementation of the default TraceTrait handling GarbageCollected and
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// GarbageCollectedMixin.
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template <typename T,
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bool =
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IsGarbageCollectedMixinTypeV<typename std::remove_const<T>::type>>
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struct TraceTraitImpl;
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} // namespace internal
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/**
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* Callback for invoking tracing on a given object.
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*
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* \param visitor The visitor to dispatch to.
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* \param object The object to invoke tracing on.
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*/
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using TraceCallback = void (*)(Visitor* visitor, const void* object);
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/**
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* Describes how to trace an object, i.e., how to visit all Oilpan-relevant
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* fields of an object.
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*/
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struct TraceDescriptor {
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/**
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* Adjusted base pointer, i.e., the pointer to the class inheriting directly
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* from GarbageCollected, of the object that is being traced.
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*/
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const void* base_object_payload;
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/**
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* Callback for tracing the object.
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*/
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TraceCallback callback;
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};
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namespace internal {
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struct V8_EXPORT TraceTraitFromInnerAddressImpl {
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static TraceDescriptor GetTraceDescriptor(const void* address);
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};
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/**
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* Trait specifying how the garbage collector processes an object of type T.
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*
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* Advanced users may override handling by creating a specialization for their
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* type.
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*/
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template <typename T>
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struct TraceTraitBase {
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static_assert(internal::IsTraceableV<T>, "T must have a Trace() method");
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/**
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* Accessor for retrieving a TraceDescriptor to process an object of type T.
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*
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* \param self The object to be processed.
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* \returns a TraceDescriptor to process the object.
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*/
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static TraceDescriptor GetTraceDescriptor(const void* self) {
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return internal::TraceTraitImpl<T>::GetTraceDescriptor(
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static_cast<const T*>(self));
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}
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/**
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* Function invoking the tracing for an object of type T.
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*
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* \param visitor The visitor to dispatch to.
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* \param self The object to invoke tracing on.
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*/
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static void Trace(Visitor* visitor, const void* self) {
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static_cast<const T*>(self)->Trace(visitor);
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}
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};
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} // namespace internal
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template <typename T>
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struct TraceTrait : public internal::TraceTraitBase<T> {};
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namespace internal {
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template <typename T>
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struct TraceTraitImpl<T, false> {
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static_assert(IsGarbageCollectedTypeV<T>,
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"T must be of type GarbageCollected or GarbageCollectedMixin");
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static TraceDescriptor GetTraceDescriptor(const void* self) {
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return {self, TraceTrait<T>::Trace};
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}
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};
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template <typename T>
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struct TraceTraitImpl<T, true> {
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static TraceDescriptor GetTraceDescriptor(const void* self) {
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return internal::TraceTraitFromInnerAddressImpl::GetTraceDescriptor(self);
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}
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};
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} // namespace internal
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} // namespace cppgc
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#endif // INCLUDE_CPPGC_TRACE_TRAIT_H_
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