Source/platform/heap/Handle.h - Issue 1213133002: Oilpan: Reduce sizeof(Persistent) to 16 byte

Unified Diff: Source/platform/heap/Handle.h

Issue 1213133002: Oilpan: Reduce sizeof(Persistent) to 16 byte (Closed) Base URL: svn://svn.chromium.org/blink/trunk

Patch Set: Created 5 years, 6 months ago

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Index: Source/platform/heap/Handle.h

diff --git a/Source/platform/heap/Handle.h b/Source/platform/heap/Handle.h

index be0446348e8cf45e0c490c668f963b2f6b3f9159..9b0bbaa49433a2373edb9daf66be907a91a26250 100644

--- a/Source/platform/heap/Handle.h

+++ b/Source/platform/heap/Handle.h

@@ -34,12 +34,14 @@

#include "platform/heap/Heap.h"

#include "platform/heap/HeapAllocator.h"

#include "platform/heap/InlinedGlobalMarkingVisitor.h"

+#include "platform/heap/PersistentNode.h"

#include "platform/heap/ThreadState.h"

#include "platform/heap/TraceTraits.h"

#include "platform/heap/Visitor.h"

#include "wtf/Functional.h"

#include "wtf/HashFunctions.h"

#include "wtf/Locker.h"

+#include "wtf/MainThread.h"

#include "wtf/RawPtr.h"

#include "wtf/RefCounted.h"

#include "wtf/TypeTraits.h"

@@ -48,88 +50,6 @@ namespace blink {

template<typename T> class HeapTerminatedArray;

-class PersistentNode {

-public:

- explicit PersistentNode(TraceCallback trace)

- : m_trace(trace)

- {

- }

- NO_LAZY_SWEEP_SANITIZE_ADDRESS

- bool isHeapObjectAlive() { return m_trace; }

- // This operator= is important. Without having the operator=, m_next and

- // m_prev are inproperly copied and it breaks the link list of the

- // persistent handles.

- inline PersistentNode& operator=(const PersistentNode& otherref) { return *this; }

-private:

- // Ideally the trace method should be virtual and automatically dispatch

- // to the most specific implementation. However having a virtual method

- // on PersistentNode leads to too eager template instantiation with MSVC

- // which leads to include cycles.

- // Instead we call the constructor with a TraceCallback which knows the

- // type of the most specific child and calls trace directly. See

- // TraceMethodDelegate in Visitor.h for how this is done.

- void tracePersistentNode(Visitor* visitor)

- {

- m_trace(visitor, this);

- }

- ~PersistentNode()

- {

- }

- TraceCallback m_trace;

- PersistentNode* m_next;

- PersistentNode* m_prev;

- template<typename T> friend class CrossThreadPersistent;

- template<typename T> friend class Persistent;

- template<typename Collection> friend class PersistentHeapCollectionBase;

- friend class PersistentAnchor;

- friend class ThreadState;

-};

-// A dummy Persistent handle that ensures the list of persistents is never null.

-// This removes a test from a hot path.

-class PersistentAnchor : public PersistentNode {

-public:

- void tracePersistentNodes(Visitor* visitor)

- {

- for (PersistentNode* current = m_next; current != this; current = current->m_next)

- current->tracePersistentNode(visitor);

- }

- int numberOfPersistents()

- {

- int numberOfPersistents = 0;

- for (PersistentNode* current = m_next; current != this; current = current->m_next)

- ++numberOfPersistents;

- return numberOfPersistents;

- }

- ~PersistentAnchor()

- {

- m_trace = nullptr;

- }

- template<typename VisitorDispatcher>

- void trace(VisitorDispatcher visitor)

- {

- ASSERT_NOT_REACHED();

- }

-private:

- PersistentAnchor() : PersistentNode(TraceMethodDelegate<PersistentAnchor, &PersistentAnchor::trace>::trampoline)

- {

- m_next = this;

- m_prev = this;

- }

- friend class ThreadState;

-};

// Persistent handles are used to store pointers into the

// managed heap. As long as the Persistent handle is alive

// the GC will keep the object pointed to alive. Persistent

@@ -144,33 +64,33 @@ private:

// We have to construct and destruct Persistent in the same thread.

template<typename T>

-class Persistent : public PersistentNode {

+class Persistent final {

public:

- Persistent() : PersistentNode(TraceMethodDelegate<Persistent<T>, &Persistent<T>::trace>::trampoline), m_raw(nullptr)

+ Persistent() : m_raw(nullptr)

{

initialize();

}

- Persistent(std::nullptr_t) : PersistentNode(TraceMethodDelegate<Persistent<T>, &Persistent<T>::trace>::trampoline), m_raw(nullptr)

+ Persistent(std::nullptr_t) : m_raw(nullptr)

{

initialize();

}

- Persistent(T* raw) : PersistentNode(TraceMethodDelegate<Persistent<T>, &Persistent<T>::trace>::trampoline), m_raw(raw)

+ Persistent(T* raw) : m_raw(raw)

{

initialize();

checkPointer();

recordBacktrace();

}

- Persistent(T& raw) : PersistentNode(TraceMethodDelegate<Persistent<T>, &Persistent<T>::trace>::trampoline), m_raw(&raw)

+ Persistent(T& raw) : m_raw(&raw)

{

initialize();

checkPointer();

recordBacktrace();

}

- Persistent(const Persistent& other) : PersistentNode(TraceMethodDelegate<Persistent<T>, &Persistent<T>::trace>::trampoline), m_raw(other)

+ Persistent(const Persistent& other) : m_raw(other)

{

initialize();

checkPointer();

@@ -178,7 +98,7 @@ public:

}

template<typename U>

- Persistent(const Persistent& other) : PersistentNode(TraceMethodDelegate<Persistent<T>, &Persistent<T>::trace>::trampoline), m_raw(other)

+ Persistent(const Persistent& other) : m_raw(other)

{

initialize();

checkPointer();

@@ -186,7 +106,7 @@ public:

}

template<typename U>

- Persistent(const Member& other) : PersistentNode(TraceMethodDelegate<Persistent<T>, &Persistent<T>::trace>::trampoline), m_raw(other)

+ Persistent(const Member& other) : m_raw(other)

{

initialize();

checkPointer();

@@ -194,7 +114,7 @@ public:

}

template<typename U>

- Persistent(const RawPtr& other) : PersistentNode(TraceMethodDelegate<Persistent<T>, &Persistent<T>::trace>::trampoline), m_raw(other.get())

+ Persistent(const RawPtr& other) : m_raw(other.get())

{

initialize();

checkPointer();

@@ -207,7 +127,6 @@ public:

{

uninitialize();

m_raw = nullptr;

- m_trace = nullptr;

}

template<typename VisitorDispatcher>

@@ -292,20 +211,14 @@ private:

{

ThreadState* state = ThreadStateFor<ThreadingTrait<T>::Affinity>::state();

state->checkThread();

- m_prev = state->roots();

- m_next = m_prev->m_next;

- m_prev->m_next = this;

- m_next->m_prev = this;

+ m_persistentNode = state->persistentRegion()->allocatePersistentNode(this, TraceMethodDelegate<Persistent<T>, &Persistent<T>::trace>::trampoline);

}

- NO_LAZY_SWEEP_SANITIZE_ADDRESS

void uninitialize()

{

- ASSERT(isHeapObjectAlive());

- ASSERT(m_next->isHeapObjectAlive());

- ASSERT(m_prev->isHeapObjectAlive());

- m_next->m_prev = m_prev;

- m_prev->m_next = m_next;

+ ThreadState* state = ThreadStateFor<ThreadingTrait<T>::Affinity>::state();

+ state->checkThread();

+ state->persistentRegion()->freePersistentNode(m_persistentNode);

}

void checkPointer()

@@ -337,39 +250,41 @@ private:

#else

inline void recordBacktrace() const { }

#endif

+ // m_raw is accessed most, so put it at the first field.

T* m_raw;

+ PersistentNode* m_persistentNode;

};

// Unlike Persistent, we can destruct a CrossThreadPersistent in a thread

// different from the construction thread.

template<typename T>

-class CrossThreadPersistent : public PersistentNode {

+class CrossThreadPersistent final {

public:

- CrossThreadPersistent() : PersistentNode(TraceMethodDelegate<CrossThreadPersistent<T>, &CrossThreadPersistent<T>::trace>::trampoline), m_raw(nullptr)

+ CrossThreadPersistent() : m_raw(nullptr)

{

initialize();

}

- CrossThreadPersistent(std::nullptr_t) : PersistentNode(TraceMethodDelegate<CrossThreadPersistent<T>, &CrossThreadPersistent<T>::trace>::trampoline), m_raw(nullptr)

+ CrossThreadPersistent(std::nullptr_t) : m_raw(nullptr)

{

initialize();

}

- CrossThreadPersistent(T* raw) : PersistentNode(TraceMethodDelegate<CrossThreadPersistent<T>, &CrossThreadPersistent<T>::trace>::trampoline), m_raw(raw)

+ CrossThreadPersistent(T* raw) : m_raw(raw)

{

initialize();

checkPointer();

recordBacktrace();

}

- CrossThreadPersistent(T& raw) : PersistentNode(TraceMethodDelegate<CrossThreadPersistent<T>, &CrossThreadPersistent<T>::trace>::trampoline), m_raw(&raw)

+ CrossThreadPersistent(T& raw) : m_raw(&raw)

{

initialize();

checkPointer();

recordBacktrace();

}

- CrossThreadPersistent(const CrossThreadPersistent& other) : PersistentNode(TraceMethodDelegate<CrossThreadPersistent<T>, &CrossThreadPersistent<T>::trace>::trampoline), m_raw(other)

+ CrossThreadPersistent(const CrossThreadPersistent& other) : m_raw(other)

{

initialize();

checkPointer();

@@ -377,7 +292,7 @@ public:

}

template<typename U>

- CrossThreadPersistent(const CrossThreadPersistent& other) : PersistentNode(TraceMethodDelegate<CrossThreadPersistent<T>, &CrossThreadPersistent<T>::trace>::trampoline), m_raw(other)

+ CrossThreadPersistent(const CrossThreadPersistent& other) : m_raw(other)

{

initialize();

checkPointer();

@@ -385,7 +300,7 @@ public:

}

template<typename U>

- CrossThreadPersistent(const Member& other) : PersistentNode(TraceMethodDelegate<CrossThreadPersistent<T>, &CrossThreadPersistent<T>::trace>::trampoline), m_raw(other)

+ CrossThreadPersistent(const Member& other) : m_raw(other)

{

initialize();

checkPointer();

@@ -393,7 +308,7 @@ public:

}

template<typename U>

- CrossThreadPersistent(const RawPtr& other) : PersistentNode(TraceMethodDelegate<CrossThreadPersistent<T>, &CrossThreadPersistent<T>::trace>::trampoline), m_raw(other.get())

+ CrossThreadPersistent(const RawPtr& other) : m_raw(other.get())

{

initialize();

checkPointer();

@@ -406,7 +321,6 @@ public:

{

uninitialize();

m_raw = nullptr;

- m_trace = nullptr;

}

template<typename VisitorDispatcher>

@@ -489,22 +403,12 @@ private:

NO_LAZY_SWEEP_SANITIZE_ADDRESS

void initialize()

{

- MutexLocker m_locker(ThreadState::globalRootsMutex());

- m_prev = &ThreadState::globalRoots();

- m_next = m_prev->m_next;

- m_prev->m_next = this;

- m_next->m_prev = this;

+ m_persistentNode = ThreadState::crossThreadPersistentRegion().allocatePersistentNode(this, TraceMethodDelegate<CrossThreadPersistent<T>, &CrossThreadPersistent<T>::trace>::trampoline);

}

- NO_LAZY_SWEEP_SANITIZE_ADDRESS

void uninitialize()

{

- MutexLocker m_locker(ThreadState::globalRootsMutex());

- ASSERT(isHeapObjectAlive());

- ASSERT(m_next->isHeapObjectAlive());

- ASSERT(m_prev->isHeapObjectAlive());

- m_next->m_prev = m_prev;

- m_prev->m_next = m_next;

+ ThreadState::crossThreadPersistentRegion().freePersistentNode(m_persistentNode);

}

void checkPointer()

@@ -535,31 +439,33 @@ private:

#else

inline void recordBacktrace() const { }

#endif

+ // m_raw is accessed most, so put it at the first field.

T* m_raw;

+ PersistentNode* m_persistentNode;

};

// PersistentNode must be the left-most class to let the

// visitor->trace(static_cast<Collection*>(this)) trace the correct position.

// FIXME: derive affinity based on the collection.

template<typename Collection>

-class PersistentHeapCollectionBase : public PersistentNode, public Collection {

+class PersistentHeapCollectionBase : public Collection {

// We overload the various new and delete operators with using the WTF DefaultAllocator to ensure persistent

// heap collections are always allocated off-heap. This allows persistent collections to be used in

// DEFINE_STATIC_LOCAL et. al.

WTF_USE_ALLOCATOR(PersistentHeapCollectionBase, WTF::DefaultAllocator);

public:

- PersistentHeapCollectionBase() : PersistentNode(TraceMethodDelegate<PersistentHeapCollectionBase<Collection>, &PersistentHeapCollectionBase<Collection>::trace>::trampoline)

+ PersistentHeapCollectionBase()

{

initialize();

}

- PersistentHeapCollectionBase(const PersistentHeapCollectionBase& other) : PersistentNode(TraceMethodDelegate<PersistentHeapCollectionBase<Collection>, &PersistentHeapCollectionBase<Collection>::trace>::trampoline), Collection(other)

+ PersistentHeapCollectionBase(const PersistentHeapCollectionBase& other) : Collection(other)

{

initialize();

}

template<typename OtherCollection>

- PersistentHeapCollectionBase(const OtherCollection& other) : PersistentNode(TraceMethodDelegate<PersistentHeapCollectionBase<Collection>, &PersistentHeapCollectionBase<Collection>::trace>::trampoline), Collection(other)

+ PersistentHeapCollectionBase(const OtherCollection& other) : Collection(other)

{

initialize();

}

@@ -567,7 +473,6 @@ public:

~PersistentHeapCollectionBase()

{

uninitialize();

- m_trace = nullptr;

}

template<typename VisitorDispatcher>

@@ -582,21 +487,18 @@ private:

void initialize()

{

ThreadState* state = ThreadState::current();

- m_prev = state->roots();

- m_next = m_prev->m_next;

- m_prev->m_next = this;

- m_next->m_prev = this;

+ state->checkThread();

+ m_persistentNode = state->persistentRegion()->allocatePersistentNode(this, TraceMethodDelegate<PersistentHeapCollectionBase<Collection>, &PersistentHeapCollectionBase<Collection>::trace>::trampoline);

}

- NO_LAZY_SWEEP_SANITIZE_ADDRESS

void uninitialize()

{

- ASSERT(isHeapObjectAlive());

- ASSERT(m_next->isHeapObjectAlive());

- ASSERT(m_prev->isHeapObjectAlive());

- m_next->m_prev = m_prev;

- m_prev->m_next = m_next;

+ ThreadState* state = ThreadState::current();

+ state->checkThread();

+ state->persistentRegion()->freePersistentNode(m_persistentNode);

}

+ PersistentNode* m_persistentNode;

};

template<

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