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/*
* Copyright (C) 2008, 2013, 2014, 2015 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 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.
*/
#include "config.h"
#include "JSStackInlines.h"
#include "ConservativeRoots.h"
#include "Interpreter.h"
#include "JSCInlines.h"
#include "Options.h"
#include <wtf/Lock.h>
namespace JSC {
#if !ENABLE(JIT)
static size_t committedBytesCount = 0;
static size_t commitSize()
{
static size_t size = std::max<size_t>(16 * 1024, pageSize());
return size;
}
static StaticLock stackStatisticsMutex;
#endif // !ENABLE(JIT)
JSStack::JSStack(VM& vm)
: m_vm(vm)
, m_topCallFrame(vm.topCallFrame)
#if !ENABLE(JIT)
, m_end(0)
, m_reservedZoneSizeInRegisters(0)
#endif
{
#if !ENABLE(JIT)
size_t capacity = Options::maxPerThreadStackUsage();
ASSERT(capacity && isPageAligned(capacity));
m_reservation = PageReservation::reserve(WTF::roundUpToMultipleOf(commitSize(), capacity), OSAllocator::JSVMStackPages);
setStackLimit(highAddress());
m_commitTop = highAddress();
m_lastStackTop = baseOfStack();
#endif // !ENABLE(JIT)
m_topCallFrame = 0;
}
#if !ENABLE(JIT)
JSStack::~JSStack()
{
ptrdiff_t sizeToDecommit = reinterpret_cast<char*>(highAddress()) - reinterpret_cast<char*>(m_commitTop);
m_reservation.decommit(reinterpret_cast<void*>(m_commitTop), sizeToDecommit);
addToCommittedByteCount(-sizeToDecommit);
m_reservation.deallocate();
}
bool JSStack::growSlowCase(Register* newTopOfStack)
{
Register* newTopOfStackWithReservedZone = newTopOfStack - m_reservedZoneSizeInRegisters;
// If we have already committed enough memory to satisfy this request,
// just update the end pointer and return.
if (newTopOfStackWithReservedZone >= m_commitTop) {
setStackLimit(newTopOfStack);
return true;
}
// Compute the chunk size of additional memory to commit, and see if we
// have it is still within our budget. If not, we'll fail to grow and
// return false.
ptrdiff_t delta = reinterpret_cast<char*>(m_commitTop) - reinterpret_cast<char*>(newTopOfStackWithReservedZone);
delta = WTF::roundUpToMultipleOf(commitSize(), delta);
Register* newCommitTop = m_commitTop - (delta / sizeof(Register));
if (newCommitTop < reservationTop())
return false;
// Otherwise, the growth is still within our budget. Commit it and return true.
m_reservation.commit(newCommitTop, delta);
addToCommittedByteCount(delta);
m_commitTop = newCommitTop;
setStackLimit(newTopOfStack);
return true;
}
void JSStack::gatherConservativeRoots(ConservativeRoots& conservativeRoots, JITStubRoutineSet& jitStubRoutines, CodeBlockSet& codeBlocks)
{
conservativeRoots.add(topOfStack() + 1, highAddress(), jitStubRoutines, codeBlocks);
}
void JSStack::sanitizeStack()
{
#if !ASAN_ENABLED
ASSERT(topOfStack() <= baseOfStack());
if (m_lastStackTop < topOfStack()) {
char* begin = reinterpret_cast<char*>(m_lastStackTop + 1);
char* end = reinterpret_cast<char*>(topOfStack() + 1);
memset(begin, 0, end - begin);
}
m_lastStackTop = topOfStack();
#endif
}
void JSStack::releaseExcessCapacity()
{
Register* highAddressWithReservedZone = highAddress() - m_reservedZoneSizeInRegisters;
ptrdiff_t delta = reinterpret_cast<char*>(highAddressWithReservedZone) - reinterpret_cast<char*>(m_commitTop);
m_reservation.decommit(m_commitTop, delta);
addToCommittedByteCount(-delta);
m_commitTop = highAddressWithReservedZone;
}
void JSStack::addToCommittedByteCount(long byteCount)
{
LockHolder locker(stackStatisticsMutex);
ASSERT(static_cast<long>(committedBytesCount) + byteCount > -1);
committedBytesCount += byteCount;
}
void JSStack::setReservedZoneSize(size_t reservedZoneSize)
{
m_reservedZoneSizeInRegisters = reservedZoneSize / sizeof(Register);
if (m_commitTop >= (m_end + 1) - m_reservedZoneSizeInRegisters)
growSlowCase(m_end + 1);
}
#endif // !ENABLE(JIT)
#if ENABLE(JIT)
Register* JSStack::lowAddress() const
{
ASSERT(wtfThreadData().stack().isGrowingDownward());
return reinterpret_cast<Register*>(m_vm.stackLimit());
}
Register* JSStack::highAddress() const
{
ASSERT(wtfThreadData().stack().isGrowingDownward());
return reinterpret_cast<Register*>(wtfThreadData().stack().origin());
}
#endif // ENABLE(JIT)
size_t JSStack::committedByteCount()
{
#if !ENABLE(JIT)
LockHolder locker(stackStatisticsMutex);
return committedBytesCount;
#else
// When using the C stack, we don't know how many stack pages are actually
// committed. So, we use the current stack usage as an estimate.
ASSERT(wtfThreadData().stack().isGrowingDownward());
int8_t* current = reinterpret_cast<int8_t*>(¤t);
int8_t* high = reinterpret_cast<int8_t*>(wtfThreadData().stack().origin());
return high - current;
#endif
}
} // namespace JSC
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