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cosmopolitan/third_party/libcxx/bit
Justine Tunney cf93ecbbb2 Prove that Makefile is fully defined 
The whole repository is now buildable with GNU Make Landlock sandboxing.
This proves that no Makefile targets exist which touch files other than
their declared prerequisites. In order to do this, we had to:

  1. Stop code morphing GCC output in package.com and instead run a
     newly introduced FIXUPOBJ.COM command after GCC invocations.

  2. Disable all the crumby Python unit tests that do things like create
     files in the current directory, or rename() files between folders.
     This ended up being a lot of tests, but most of them are still ok.

  3. Introduce an .UNSANDBOXED variable to GNU Make to disable Landlock.
     We currently only do this for things like `make tags`.

  4. This change deletes some GNU Make code that was preventing the
     execve() optimization from working. This means it should no longer
     be necessary in most cases for command invocations to be indirected
     through the cocmd interpreter.

  5. Missing dependencies had to be declared in certain places, in cases
     where they couldn't be automatically determined by MKDEPS.COM

  6. The libcxx header situation has finally been tamed. One of the
     things that makes this difficult is MKDEPS.COM only wants to
     consider the first 64kb of a file, in order to go fast. But libcxx
     likes to have #include lines buried after huge documentation.

  7. An .UNVEIL variable has been introduced to GNU Make just in case
     we ever wish to explicitly specify additional things that need to
     be whitelisted which aren't strictly prerequisites. This works in
     a manner similar to the recently introduced .EXTRA_PREREQS feature.

There's now a new build/bootstrap/make.com prebuilt binary available. It
should no longer be possible to write invalid Makefile code.
2022-08-06 04:05:08 -07:00

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// -*- C++ -*-
//===------------------------------ bit ----------------------------------===//
//
// 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_BIT
#define _LIBCPP_BIT
#include "third_party/libcxx/__config"
#include "third_party/libcxx/limits"
#include "third_party/libcxx/type_traits"
#include "third_party/libcxx/version"
#include "third_party/libcxx/__debug"
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include "third_party/libcxx/__undef_macros"
_LIBCPP_BEGIN_NAMESPACE_STD
/*
bit synopsis
namespace std {
template <class T>
constexpr bool ispow2(T x) noexcept; // C++20
template <class T>
constexpr T ceil2(T x); // C++20
template <class T>
constexpr T floor2(T x) noexcept; // C++20
template <class T>
constexpr T log2p1(T x) noexcept; // C++20
// 23.20.2, rotating
template<class T>
constexpr T rotl(T x, unsigned int s) noexcept; // C++20
template<class T>
constexpr T rotr(T x, unsigned int s) noexcept; // C++20
// 23.20.3, counting
template<class T>
constexpr int countl_zero(T x) noexcept; // C++20
template<class T>
constexpr int countl_one(T x) noexcept; // C++20
template<class T>
constexpr int countr_zero(T x) noexcept; // C++20
template<class T>
constexpr int countr_one(T x) noexcept; // C++20
template<class T>
constexpr int popcount(T x) noexcept; // C++20
// 20.15.9, endian
enum class endian {
little = see below, // C++20
big = see below, // C++20
native = see below // C++20
};
} // 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)
(defined(_M_AMD64) || defined(__x86_64__))
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
template <class _Tp>
using __bitop_unsigned_integer _LIBCPP_NODEBUG_TYPE = integral_constant<bool,
is_integral<_Tp>::value &&
is_unsigned<_Tp>::value &&
_IsNotSame<typename remove_cv<_Tp>::type, bool>::value &&
_IsNotSame<typename remove_cv<_Tp>::type, signed char>::value &&
_IsNotSame<typename remove_cv<_Tp>::type, wchar_t>::value &&
_IsNotSame<typename remove_cv<_Tp>::type, char16_t>::value &&
_IsNotSame<typename remove_cv<_Tp>::type, char32_t>::value
>;
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
_Tp __rotl(_Tp __t, unsigned int __cnt) _NOEXCEPT
{
static_assert(__bitop_unsigned_integer<_Tp>::value, "__rotl requires unsigned");
const unsigned int __dig = numeric_limits<_Tp>::digits;
if ((__cnt % __dig) == 0)
return __t;
return (__t << (__cnt % __dig)) | (__t >> (__dig - (__cnt % __dig)));
}
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
_Tp __rotr(_Tp __t, unsigned int __cnt) _NOEXCEPT
{
static_assert(__bitop_unsigned_integer<_Tp>::value, "__rotr requires unsigned");
const unsigned int __dig = numeric_limits<_Tp>::digits;
if ((__cnt % __dig) == 0)
return __t;
return (__t >> (__cnt % __dig)) | (__t << (__dig - (__cnt % __dig)));
}
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
int __countr_zero(_Tp __t) _NOEXCEPT
{
static_assert(__bitop_unsigned_integer<_Tp>::value, "__countr_zero requires unsigned");
if (__t == 0)
return numeric_limits<_Tp>::digits;
if (sizeof(_Tp) <= sizeof(unsigned int))
return __libcpp_ctz(static_cast<unsigned int>(__t));
else if (sizeof(_Tp) <= sizeof(unsigned long))
return __libcpp_ctz(static_cast<unsigned long>(__t));
else if (sizeof(_Tp) <= sizeof(unsigned long long))
return __libcpp_ctz(static_cast<unsigned long long>(__t));
else
{
int __ret = 0;
int __iter = 0;
const unsigned int __ulldigits = numeric_limits<unsigned long long>::digits;
while ((__iter = __libcpp_ctz(static_cast<unsigned long long>(__t))) == __ulldigits)
{
__ret += __iter;
__t >>= __ulldigits;
}
return __ret + __iter;
}
}
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
int __countl_zero(_Tp __t) _NOEXCEPT
{
static_assert(__bitop_unsigned_integer<_Tp>::value, "__countl_zero requires unsigned");
if (__t == 0)
return numeric_limits<_Tp>::digits;
if (sizeof(_Tp) <= sizeof(unsigned int))
return __libcpp_clz(static_cast<unsigned int>(__t))
- (numeric_limits<unsigned int>::digits - numeric_limits<_Tp>::digits);
else if (sizeof(_Tp) <= sizeof(unsigned long))
return __libcpp_clz(static_cast<unsigned long>(__t))
- (numeric_limits<unsigned long>::digits - numeric_limits<_Tp>::digits);
else if (sizeof(_Tp) <= sizeof(unsigned long long))
return __libcpp_clz(static_cast<unsigned long long>(__t))
- (numeric_limits<unsigned long long>::digits - numeric_limits<_Tp>::digits);
else
{
int __ret = 0;
int __iter = 0;
const unsigned int __ulldigits = numeric_limits<unsigned long long>::digits;
while (true) {
__t = __rotr(__t, __ulldigits);
if ((__iter = __countl_zero(static_cast<unsigned long long>(__t))) != __ulldigits)
break;
__ret += __iter;
}
return __ret + __iter;
}
}
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
int __countl_one(_Tp __t) _NOEXCEPT
{
static_assert(__bitop_unsigned_integer<_Tp>::value, "__countl_one requires unsigned");
return __t != numeric_limits<_Tp>::max()
? __countl_zero(static_cast<_Tp>(~__t))
: numeric_limits<_Tp>::digits;
}
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
int __countr_one(_Tp __t) _NOEXCEPT
{
static_assert(__bitop_unsigned_integer<_Tp>::value, "__countr_one requires unsigned");
return __t != numeric_limits<_Tp>::max()
? __countr_zero(static_cast<_Tp>(~__t))
: numeric_limits<_Tp>::digits;
}
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
int
__popcount(_Tp __t) _NOEXCEPT
{
static_assert(__bitop_unsigned_integer<_Tp>::value, "__libcpp_popcount requires unsigned");
if (sizeof(_Tp) <= sizeof(unsigned int))
return __libcpp_popcount(static_cast<unsigned int>(__t));
else if (sizeof(_Tp) <= sizeof(unsigned long))
return __libcpp_popcount(static_cast<unsigned long>(__t));
else if (sizeof(_Tp) <= sizeof(unsigned long long))
return __libcpp_popcount(static_cast<unsigned long long>(__t));
else
{
int __ret = 0;
while (__t != 0)
{
__ret += __libcpp_popcount(static_cast<unsigned long long>(__t));
__t >>= numeric_limits<unsigned long long>::digits;
}
return __ret;
}
}
// integral log base 2
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
unsigned __bit_log2(_Tp __t) _NOEXCEPT
{
static_assert(__bitop_unsigned_integer<_Tp>::value, "__bit_log2 requires unsigned");
return std::numeric_limits<_Tp>::digits - 1 - __countl_zero(__t);
}
template <class _Tp>
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
bool __ispow2(_Tp __t) _NOEXCEPT
{
static_assert(__bitop_unsigned_integer<_Tp>::value, "__ispow2 requires unsigned");
return __t != 0 && (((__t & (__t - 1)) == 0));
}
#if _LIBCPP_STD_VER > 17
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
enable_if_t<__bitop_unsigned_integer<_Tp>::value, _Tp>
rotl(_Tp __t, unsigned int __cnt) noexcept
{
return __rotl(__t, __cnt);
}
// rotr
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
enable_if_t<__bitop_unsigned_integer<_Tp>::value, _Tp>
rotr(_Tp __t, unsigned int __cnt) noexcept
{
return __rotr(__t, __cnt);
}
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
enable_if_t<__bitop_unsigned_integer<_Tp>::value, int>
countl_zero(_Tp __t) noexcept
{
return __countl_zero(__t);
}
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
enable_if_t<__bitop_unsigned_integer<_Tp>::value, int>
countl_one(_Tp __t) noexcept
{
return __countl_one(__t);
}
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
enable_if_t<__bitop_unsigned_integer<_Tp>::value, int>
countr_zero(_Tp __t) noexcept
{
return __countr_zero(__t);
}
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
enable_if_t<__bitop_unsigned_integer<_Tp>::value, int>
countr_one(_Tp __t) noexcept
{
return __countr_one(__t);
}
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
enable_if_t<__bitop_unsigned_integer<_Tp>::value, int>
popcount(_Tp __t) noexcept
{
return __popcount(__t);
}
template <class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
enable_if_t<__bitop_unsigned_integer<_Tp>::value, bool>
ispow2(_Tp __t) noexcept
{
return __ispow2(__t);
}
template <class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
enable_if_t<__bitop_unsigned_integer<_Tp>::value, _Tp>
floor2(_Tp __t) noexcept
{
return __t == 0 ? 0 : _Tp{1} << __bit_log2(__t);
}
template <class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
enable_if_t<__bitop_unsigned_integer<_Tp>::value, _Tp>
ceil2(_Tp __t) noexcept
{
if (__t < 2) return 1;
const unsigned __n = numeric_limits<_Tp>::digits - countl_zero((_Tp)(__t - 1u));
_LIBCPP_DEBUG_ASSERT(__libcpp_is_constant_evaluated() || __n != numeric_limits<_Tp>::digits, "Bad input to ceil2");
if constexpr (sizeof(_Tp) >= sizeof(unsigned))
return _Tp{1} << __n;
else
{
const unsigned __extra = numeric_limits<unsigned>::digits - numeric_limits<_Tp>::digits;
const unsigned __retVal = 1u << (__n + __extra);
return (_Tp) (__retVal >> __extra);
}
}
template <class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
enable_if_t<__bitop_unsigned_integer<_Tp>::value, _Tp>
log2p1(_Tp __t) noexcept
{
return __t == 0 ? 0 : __bit_log2(__t) + 1;
}
enum class endian
{
little = 0xDEAD,
big = 0xFACE,
#if defined(_LIBCPP_LITTLE_ENDIAN)
native = little
#elif defined(_LIBCPP_BIG_ENDIAN)
native = big
#else
native = 0xCAFE
#endif
};
#endif // _LIBCPP_STD_VER > 17
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP_BIT
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