/* * 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 StackAlignment_h #define StackAlignment_h #include "JSCJSValue.h" #include "JSStack.h" #include <wtf/MathExtras.h> namespace JSC { // NB. Different platforms may have different requirements here. But 16 bytes is very common. inline unsigned stackAlignmentBytes() { return 16; } inline 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 + JSStack::CallFrameHeaderSize) - JSStack::CallFrameHeaderSize; } // 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 JSStack::CallerFrameAndPCSize inline unsigned roundLocalRegisterCountForFramePointerOffset(unsigned localRegisterCount) { return WTF::roundUpToMultipleOf(stackAlignmentRegisters(), localRegisterCount + JSStack::CallerFrameAndPCSize) - JSStack::CallerFrameAndPCSize; } inline unsigned logStackAlignmentRegisters() { return WTF::fastLog2(stackAlignmentRegisters()); } } // namespace JSC #endif // StackAlignment_h