darling-JavaScriptCore/runtime/StackAlignment.h
2020-08-29 15:28:47 -04:00

62 lines
2.5 KiB
C++

/*
* Copyright (C) 2013, 2016 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.
*/
#pragma once
#include "CallFrame.h"
#include "JSCJSValue.h"
#include <wtf/MathExtras.h>
namespace JSC {
// NB. Different platforms may have different requirements here. But 16 bytes is very common.
constexpr unsigned stackAlignmentBytes() { return 16; }
constexpr unsigned stackAlignmentRegisters()
{
return stackAlignmentBytes() / sizeof(EncodedJSValue);
}
// Align argument count taking into account the CallFrameHeaderSize may be
// an "unaligned" count of registers.
inline unsigned roundArgumentCountToAlignFrame(unsigned argumentCount)
{
return WTF::roundUpToMultipleOf(stackAlignmentRegisters(), argumentCount + CallFrame::headerSizeInRegisters) - CallFrame::headerSizeInRegisters;
}
// Align local register count to make the last local end on a stack aligned address given the
// CallFrame is at an address that is stack aligned minus CallerFrameAndPC::sizeInRegisters
inline unsigned roundLocalRegisterCountForFramePointerOffset(unsigned localRegisterCount)
{
return WTF::roundUpToMultipleOf(stackAlignmentRegisters(), localRegisterCount + CallerFrameAndPC::sizeInRegisters) - CallerFrameAndPC::sizeInRegisters;
}
inline unsigned logStackAlignmentRegisters()
{
return WTF::fastLog2(stackAlignmentRegisters());
}
} // namespace JSC