1/*
2 * Copyright (C) 2018 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#include "config.h"
27#include "StackPointer.h"
28
29namespace WTF {
30
31#if USE(GENERIC_CURRENT_STACK_POINTER)
32constexpr size_t sizeOfFrameHeader = 2 * sizeof(void*);
33
34SUPPRESS_ASAN NEVER_INLINE
35void* currentStackPointer()
36{
37#if COMPILER(GCC_COMPATIBLE)
38 return reinterpret_cast<uint8_t*>(__builtin_frame_address(0)) + sizeOfFrameHeader;
39#else
40 // Make sure that sp is the only local variable declared in this function.
41 void* sp = reinterpret_cast<uint8_t*>(&sp) + sizeOfFrameHeader + sizeof(sp);
42 return sp;
43#endif
44}
45#endif // USE(GENERIC_CURRENT_STACK_POINTER)
46
47} // namespace WTF
48