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/*
* Copyright (C) 2013 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.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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 INC. OR
* 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 VMStackBounds_h
#define VMStackBounds_h
#include "VM.h"
#include <wtf/StackBounds.h>
namespace JSC {
class VMStackBounds {
public:
VMStackBounds(VM& vm, const StackBounds& bounds)
: m_vm(vm)
, m_bounds(bounds)
{
}
bool isSafeToRecurse() const { return m_bounds.isSafeToRecurse(requiredCapacity()); }
private:
inline size_t requiredCapacity() const
{
Interpreter* interpreter = m_vm.interpreter;
// We have two separate stack limits, one for regular JS execution, and one
// for when we're handling errors. We need the error stack to be smaller
// otherwise there would obviously not be any stack left to execute JS in when
// there's a stack overflow.
//
// These sizes were derived from the stack usage of a number of sites when
// layout occurs when we've already consumed most of the C stack.
const size_t requiredStack = 128 * KB;
const size_t errorModeRequiredStack = 64 * KB;
size_t requiredCapacity = interpreter->isInErrorHandlingMode() ? errorModeRequiredStack : requiredStack;
RELEASE_ASSERT(m_bounds.size() >= requiredCapacity);
return requiredCapacity;
}
VM& m_vm;
const StackBounds& m_bounds;
};
} // namespace JSC
#endif // VMStackBounds_h
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