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// Copyright 2018 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_MARKING_VERIFIER_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_HEAP_MARKING_VERIFIER_H_
#include "third_party/blink/renderer/platform/heap/garbage_collected.h"
#include "third_party/blink/renderer/platform/heap/heap_page.h"
#include "third_party/blink/renderer/platform/heap/visitor.h"
namespace blink {
// Marking verifier that checks that a child is marked if its parent is marked.
class MarkingVerifier final : public Visitor {
public:
explicit MarkingVerifier(ThreadState* state) : Visitor(state) {}
~MarkingVerifier() override {}
void VerifyObject(HeapObjectHeader* header) {
// Verify only non-free marked objects.
if (header->IsFree() || !header->IsMarked())
return;
const GCInfo* info =
GCInfoTable::Get().GCInfoFromIndex(header->GcInfoIndex());
const bool can_verify =
!info->HasVTable() || blink::VTableInitialized(header->Payload());
if (can_verify) {
CHECK(header->IsValid());
info->trace_(this, header->Payload());
}
}
void Visit(void* object, TraceDescriptor desc) final {
CHECK(object);
VerifyChild(desc.base_object_payload);
}
void VisitWeak(void* object,
void** object_slot,
TraceDescriptor desc,
WeakCallback callback) final {
CHECK(object);
VerifyChild(desc.base_object_payload);
}
// Unused overrides.
void VisitBackingStoreStrongly(void*, void**, TraceDescriptor) final {}
void VisitBackingStoreWeakly(void*,
void**,
TraceDescriptor,
WeakCallback,
void*) final {}
void VisitBackingStoreOnly(void*, void**) final {}
void RegisterBackingStoreCallback(void**, MovingObjectCallback, void*) final {
}
void RegisterWeakCallback(void*, WeakCallback) final {}
void Visit(const TraceWrapperV8Reference<v8::Value>&) final {}
void Visit(DOMWrapperMap<ScriptWrappable>*,
const ScriptWrappable* key) final {}
void VisitWithWrappers(void*, TraceDescriptor) final {}
private:
void VerifyChild(void* base_object_payload) {
// The following check ensures that an object is currently not under
// construction. All verifier runs are assumed to be run outside of mixin
// construction. Consequently, the following cases can lead to a failing
// check:
// 1. The garbage collector ignoring no-GC scopes for mixin construction.
// 2. Missing macro USING_GARBAGE_COLLECTED_MIXIN for users of
// GarbageCollectedMixin.
CHECK(base_object_payload);
HeapObjectHeader* child_header =
HeapObjectHeader::FromPayload(base_object_payload);
// These checks ensure that any children reachable from marked parents are
// also marked. If you hit these checks then marking is in an inconsistent
// state meaning that there are unmarked objects reachable from marked
// ones.
CHECK(child_header);
CHECK(child_header->IsMarked());
}
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_HEAP_MARKING_VERIFIER_H_
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