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/****************************************************************************
**
** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of Qt Creator.
**
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia. For licensing terms and
** conditions see http://qt.digia.com/licensing. For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Digia gives you certain additional
** rights. These rights are described in the Digia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
****************************************************************************/
#ifndef QV4GC_H
#define QV4GC_H
#include "qmljs_objects.h"
#include <QScopedPointer>
#define DETAILED_MM_STATS
namespace QQmlJS {
namespace VM {
class MemoryManager
{
MemoryManager(const MemoryManager &);
MemoryManager &operator=(const MemoryManager&);
struct Data;
public:
class GCBlocker
{
public:
GCBlocker(MemoryManager *mm)
: mm(mm)
, wasBlocked(mm->isGCBlocked())
{
mm->setGCBlocked(true);
}
~GCBlocker()
{
mm->setGCBlocked(wasBlocked);
}
private:
MemoryManager *mm;
bool wasBlocked;
};
public:
MemoryManager();
virtual ~MemoryManager() = 0;
// TODO: this is only for 64bit (and x86 with SSE/AVX), so exend it for other architectures to be slightly more efficient (meaning, align on 8-byte boundaries).
// Note: all occurances of "16" in alloc/dealloc are also due to the alignment.
static inline std::size_t align(std::size_t size)
{ return (size + 15) & ~0xf; }
inline Managed *allocManaged(std::size_t size)
{
size = align(size);
MMObject *o = alloc(size);
o->info.needsManagedDestructorCall = 1;
Managed *ptr = reinterpret_cast<Managed *>(&o->data);
ptr->mm = this;
return ptr;
}
inline void deallocManaged(Managed *m)
{
if (!m)
return;
assert(m->mm == this);
dealloc(toObject(m));
}
bool isGCBlocked() const;
void setGCBlocked(bool blockGC);
std::size_t runGC();
void setEnableGC(bool enableGC);
void setExecutionEngine(ExecutionEngine *engine);
void setStringPool(StringPool *stringPool);
void dumpStats() const;
protected:
struct MMObject;
#if CPU(X86_64) // 64bit and x86:
struct MMInfo {
std::size_t inUse : 1;
std::size_t markBit : 1;
std::size_t needsManagedDestructorCall : 1;
std::size_t size : 61;
MMObject *next;
};
struct MMObject {
MMInfo info;
std::size_t data;
};
#elif CPU(X86) // for 32bits:
struct MMInfo {
std::size_t inUse : 1;
std::size_t markBit : 1;
std::size_t needsManagedDestructorCall : 1;
std::size_t size : 29;
struct MMObject *next;
};
struct MMObject {
MMInfo info;
std::size_t data;
};
#endif
protected:
static inline MMObject *toObject(void *ptr) { return reinterpret_cast<MMObject *>(reinterpret_cast<char *>(ptr) - sizeof(MMInfo)); }
/// expects size to be aligned
// TODO: try to inline
MMObject *alloc(std::size_t size);
// TODO: try to inline
void dealloc(MMObject *ptr);
void scribble(MMObject *obj, int c) const;
virtual void collectRootsOnStack(QVector<VM::Object *> &roots) const = 0;
ExecutionEngine *engine() const;
#ifdef DETAILED_MM_STATS
void willAllocate(std::size_t size);
#endif // DETAILED_MM_STATS
MMObject *splitItem(MMObject *m, int newSize);
private:
void collectRoots(QVector<VM::Object *> &roots) const;
static std::size_t mark(const QVector<Object *> &objects);
std::size_t sweep(std::size_t &largestFreedBlock);
std::size_t sweep(char *chunkStart, std::size_t chunkSize, std::size_t &largestFreedBlock);
private:
QScopedPointer<Data> m_d;
};
class MemoryManagerWithoutGC: public MemoryManager
{
public:
MemoryManagerWithoutGC()
{ setEnableGC(false); }
virtual ~MemoryManagerWithoutGC();
protected:
virtual void collectRootsOnStack(QVector<VM::Object *> &roots) const;
};
class MemoryManagerWithNativeStack: public MemoryManager
{
public:
MemoryManagerWithNativeStack()
{ setEnableGC(true); }
virtual ~MemoryManagerWithNativeStack();
protected:
virtual void collectRootsOnStack(QVector<VM::Object *> &roots) const;
};
} // namespace VM
} // namespace QQmlJS
#endif // QV4GC_H
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