f46c4858b0
This reverts commit cf25b3bc53.
Reason for revert: https://crbug.com/1307471. TraceTrait must only be used during marking.
Original change's description:
> cppgc: Rework prefinalizers
>
> Move the check for whether an object is live or dead out of the
> prefinalizer trampoline. Moving it into the backend allows for
> inlining the check which avoids a call to the trampoline for live
> objects.
>
> On catapult benchmarks (e.g. cnn:2021, nytimes:2020), there's often
> ~2k finalizers registered. In order to avoid memory overhead in the
> range of a few KB, we store the fact whether the object points to the
> base object payload in the LSB of the pointer. For caged builds this
> is replaced with just storing the index into the cage for both object
> and base object payload.
>
> Locally saves around ~10% of atomic sweeping processing time which is
> in the order of .05ms.
>
> Bug: v8:12698
> Change-Id: I198205a6b1d57fc2df821ee4e73e53dc6f825ff5
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3497764
> Reviewed-by: Omer Katz <omerkatz@chromium.org>
> Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#79442}
Bug: v8:12698, chromium:1307471
Change-Id: I5c4e70d46cb99af66c77f0c013625b6af6c6eb8e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3535781
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79527}
76 lines
2.9 KiB
C++
76 lines
2.9 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_PREFINALIZER_H_
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#define INCLUDE_CPPGC_PREFINALIZER_H_
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#include "cppgc/internal/compiler-specific.h"
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#include "cppgc/liveness-broker.h"
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namespace cppgc {
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namespace internal {
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class V8_EXPORT PrefinalizerRegistration final {
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public:
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using Callback = bool (*)(const cppgc::LivenessBroker&, void*);
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PrefinalizerRegistration(void*, Callback);
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void* operator new(size_t, void* location) = delete;
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void* operator new(size_t) = delete;
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};
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} // namespace internal
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/**
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* Macro must be used in the private section of `Class` and registers a
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* prefinalization callback `void Class::PreFinalizer()`. The callback is
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* invoked on garbage collection after the collector has found an object to be
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* dead.
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*
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* Callback properties:
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* - The callback is invoked before a possible destructor for the corresponding
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* object.
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* - The callback may access the whole object graph, irrespective of whether
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* objects are considered dead or alive.
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* - The callback is invoked on the same thread as the object was created on.
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*
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* Example:
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* \code
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* class WithPrefinalizer : public GarbageCollected<WithPrefinalizer> {
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* CPPGC_USING_PRE_FINALIZER(WithPrefinalizer, Dispose);
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*
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* public:
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* void Trace(Visitor*) const {}
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* void Dispose() { prefinalizer_called = true; }
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* ~WithPrefinalizer() {
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* // prefinalizer_called == true
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* }
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* private:
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* bool prefinalizer_called = false;
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* };
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* \endcode
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*/
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#define CPPGC_USING_PRE_FINALIZER(Class, PreFinalizer) \
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public: \
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static bool InvokePreFinalizer(const cppgc::LivenessBroker& liveness_broker, \
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void* object) { \
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static_assert(cppgc::IsGarbageCollectedOrMixinTypeV<Class>, \
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"Only garbage collected objects can have prefinalizers"); \
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Class* self = static_cast<Class*>(object); \
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if (liveness_broker.IsHeapObjectAlive(self)) return false; \
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self->PreFinalizer(); \
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return true; \
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} \
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\
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private: \
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CPPGC_NO_UNIQUE_ADDRESS cppgc::internal::PrefinalizerRegistration \
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prefinalizer_dummy_{this, Class::InvokePreFinalizer}; \
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static_assert(true, "Force semicolon.")
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} // namespace cppgc
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#endif // INCLUDE_CPPGC_PREFINALIZER_H_
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