1/*
2 * Copyright (C) 2013, 2016 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#include "CallFrame.h"
29#include "JSCJSValue.h"
30#include <wtf/MathExtras.h>
31
32namespace JSC {
33
34// NB. Different platforms may have different requirements here. But 16 bytes is very common.
35constexpr unsigned stackAlignmentBytes() { return 16; }
36
37constexpr unsigned stackAlignmentRegisters()
38{
39 return stackAlignmentBytes() / sizeof(EncodedJSValue);
40}
41
42// Align argument count taking into account the CallFrameHeaderSize may be
43// an "unaligned" count of registers.
44inline unsigned roundArgumentCountToAlignFrame(unsigned argumentCount)
45{
46 return WTF::roundUpToMultipleOf(stackAlignmentRegisters(), argumentCount + CallFrame::headerSizeInRegisters) - CallFrame::headerSizeInRegisters;
47}
48
49// Align local register count to make the last local end on a stack aligned address given the
50// CallFrame is at an address that is stack aligned minus CallerFrameAndPC::sizeInRegisters
51inline unsigned roundLocalRegisterCountForFramePointerOffset(unsigned localRegisterCount)
52{
53 return WTF::roundUpToMultipleOf(stackAlignmentRegisters(), localRegisterCount + CallerFrameAndPC::sizeInRegisters) - CallerFrameAndPC::sizeInRegisters;
54}
55
56inline unsigned logStackAlignmentRegisters()
57{
58 return WTF::fastLog2(stackAlignmentRegisters());
59}
60
61} // namespace JSC
62