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/*
* Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef JSStack_h
#define JSStack_h
#include "ExecutableAllocator.h"
#include "Register.h"
#include <wtf/Noncopyable.h>
#include <wtf/PageReservation.h>
#include <wtf/VMTags.h>
namespace JSC {
class ConservativeRoots;
class DFGCodeBlocks;
class JITStubRoutineSet;
class LLIntOffsetsExtractor;
class JSStack {
WTF_MAKE_NONCOPYABLE(JSStack);
public:
enum CallFrameHeaderEntry {
CallFrameHeaderSize = 6,
ArgumentCount = -6,
CallerFrame = -5,
Callee = -4,
ScopeChain = -3,
ReturnPC = -2, // This is either an Instruction* or a pointer into JIT generated code stored as an Instruction*.
CodeBlock = -1,
};
static const size_t defaultCapacity = 512 * 1024;
static const size_t commitSize = 16 * 1024;
// Allow 8k of excess registers before we start trying to reap the stack
static const ptrdiff_t maxExcessCapacity = 8 * 1024;
JSStack(size_t capacity = defaultCapacity);
~JSStack();
void gatherConservativeRoots(ConservativeRoots&);
void gatherConservativeRoots(ConservativeRoots&, JITStubRoutineSet&, DFGCodeBlocks&);
Register* begin() const { return static_cast<Register*>(m_reservation.base()); }
Register* end() const { return m_end; }
size_t size() const { return end() - begin(); }
bool grow(Register*);
void shrink(Register*);
static size_t committedByteCount();
static void initializeThreading();
Register* const * addressOfEnd() const
{
return &m_end;
}
private:
friend class LLIntOffsetsExtractor;
bool growSlowCase(Register*);
void releaseExcessCapacity();
void addToCommittedByteCount(long);
Register* m_end;
Register* m_commitEnd;
PageReservation m_reservation;
};
inline JSStack::JSStack(size_t capacity)
: m_end(0)
{
ASSERT(capacity && isPageAligned(capacity));
m_reservation = PageReservation::reserve(roundUpAllocationSize(capacity * sizeof(Register), commitSize), OSAllocator::JSVMStackPages);
m_end = static_cast<Register*>(m_reservation.base());
m_commitEnd = static_cast<Register*>(m_reservation.base());
}
inline void JSStack::shrink(Register* newEnd)
{
if (newEnd >= m_end)
return;
m_end = newEnd;
if (m_end == m_reservation.base() && (m_commitEnd - begin()) >= maxExcessCapacity)
releaseExcessCapacity();
}
inline bool JSStack::grow(Register* newEnd)
{
if (newEnd <= m_end)
return true;
return growSlowCase(newEnd);
}
} // namespace JSC
#endif // JSStack_h
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