llvm-capstone/libcxx/include/__bits
Louis Dionne 368faacac7 [libc++] Revert "Protect users from relying on detail headers" & related changes
This commit reverts 5aaefa51 (and also partly 7f285f48e7 and b6d75682f9,
which were related to the original commit). As landed, 5aaefa51 had
unintended consequences on some downstream bots and didn't have proper
coverage upstream due to a few subtle things. Implementing this is
something we should do in libc++, however we'll first need to address
a few issues listed in https://reviews.llvm.org/D106124#3349710.

Differential Revision: https://reviews.llvm.org/D120683
2022-03-01 08:20:24 -05:00

146 lines
4.6 KiB
C++

// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___BITS
#define _LIBCPP___BITS
#include <__config>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
_LIBCPP_BEGIN_NAMESPACE_STD
#ifndef _LIBCPP_COMPILER_MSVC
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
int __libcpp_ctz(unsigned __x) _NOEXCEPT { return __builtin_ctz(__x); }
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
int __libcpp_ctz(unsigned long __x) _NOEXCEPT { return __builtin_ctzl(__x); }
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
int __libcpp_ctz(unsigned long long __x) _NOEXCEPT { return __builtin_ctzll(__x); }
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
int __libcpp_clz(unsigned __x) _NOEXCEPT { return __builtin_clz(__x); }
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
int __libcpp_clz(unsigned long __x) _NOEXCEPT { return __builtin_clzl(__x); }
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
int __libcpp_clz(unsigned long long __x) _NOEXCEPT { return __builtin_clzll(__x); }
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
int __libcpp_popcount(unsigned __x) _NOEXCEPT { return __builtin_popcount(__x); }
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
int __libcpp_popcount(unsigned long __x) _NOEXCEPT { return __builtin_popcountl(__x); }
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
int __libcpp_popcount(unsigned long long __x) _NOEXCEPT { return __builtin_popcountll(__x); }
#else // _LIBCPP_COMPILER_MSVC
// Precondition: __x != 0
inline _LIBCPP_INLINE_VISIBILITY
int __libcpp_ctz(unsigned __x) {
static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
static_assert(sizeof(unsigned long) == 4, "");
unsigned long __where;
if (_BitScanForward(&__where, __x))
return static_cast<int>(__where);
return 32;
}
inline _LIBCPP_INLINE_VISIBILITY
int __libcpp_ctz(unsigned long __x) {
static_assert(sizeof(unsigned long) == sizeof(unsigned), "");
return __ctz(static_cast<unsigned>(__x));
}
inline _LIBCPP_INLINE_VISIBILITY
int __libcpp_ctz(unsigned long long __x) {
unsigned long __where;
#if defined(_LIBCPP_HAS_BITSCAN64)
if (_BitScanForward64(&__where, __x))
return static_cast<int>(__where);
#else
// Win32 doesn't have _BitScanForward64 so emulate it with two 32 bit calls.
if (_BitScanForward(&__where, static_cast<unsigned long>(__x)))
return static_cast<int>(__where);
if (_BitScanForward(&__where, static_cast<unsigned long>(__x >> 32)))
return static_cast<int>(__where + 32);
#endif
return 64;
}
// Precondition: __x != 0
inline _LIBCPP_INLINE_VISIBILITY
int __libcpp_clz(unsigned __x) {
static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
static_assert(sizeof(unsigned long) == 4, "");
unsigned long __where;
if (_BitScanReverse(&__where, __x))
return static_cast<int>(31 - __where);
return 32; // Undefined Behavior.
}
inline _LIBCPP_INLINE_VISIBILITY
int __libcpp_clz(unsigned long __x) {
static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
return __libcpp_clz(static_cast<unsigned>(__x));
}
inline _LIBCPP_INLINE_VISIBILITY
int __libcpp_clz(unsigned long long __x) {
unsigned long __where;
#if defined(_LIBCPP_HAS_BITSCAN64)
if (_BitScanReverse64(&__where, __x))
return static_cast<int>(63 - __where);
#else
// Win32 doesn't have _BitScanReverse64 so emulate it with two 32 bit calls.
if (_BitScanReverse(&__where, static_cast<unsigned long>(__x >> 32)))
return static_cast<int>(63 - (__where + 32));
if (_BitScanReverse(&__where, static_cast<unsigned long>(__x)))
return static_cast<int>(63 - __where);
#endif
return 64; // Undefined Behavior.
}
inline _LIBCPP_INLINE_VISIBILITY int __libcpp_popcount(unsigned __x) {
static_assert(sizeof(unsigned) == 4, "");
return __popcnt(__x);
}
inline _LIBCPP_INLINE_VISIBILITY int __libcpp_popcount(unsigned long __x) {
static_assert(sizeof(unsigned long) == 4, "");
return __popcnt(__x);
}
inline _LIBCPP_INLINE_VISIBILITY int __libcpp_popcount(unsigned long long __x) {
static_assert(sizeof(unsigned long long) == 8, "");
return __popcnt64(__x);
}
#endif // _LIBCPP_COMPILER_MSVC
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP___BITS