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Fix implementation of ::abs and std::abs LWG 2192. 

Summary:
All overloads of `::abs` and `std::abs` must be present in both `<cmath>` and `<cstdlib>`. This is problematic to implement because C defines `fabs` in `math.h` and `labs` in `stdlib.h`. This introduces a circular dependency between the two headers. 

This patch implements that requirement by moving `abs` into `math.h` and making `stdlib.h` include `math.h`. In order to get the underlying C declarations from the "real" `stdlib.h` inside our `math.h` we need some trickery. Specifically we need to make `stdlib.h` include next itself.

Suggestions for a cleaner implementation are welcome.

Reviewers: mclow.lists, ldionne

Reviewed By: ldionne

Subscribers: krytarowski, fedor.sergeev, dexonsmith, jdoerfert, jsji, libcxx-commits

Differential Revision: https://reviews.llvm.org/D60097

llvm-svn: 359020
This commit is contained in:
Eric Fiselier 2019-04-23 18:01:58 +00:00
parent f945429fed
commit 1670772adc
7 changed files with 242 additions and 52 deletions
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62
libcxx/include/math.h
View File

@ -297,6 +297,9 @@ long double truncl(long double x);
#pragma GCC system_header
#endif
#define _LIBCPP_STDLIB_INCLUDE_NEXT
#include <stdlib.h>
#include_next <math.h>
#ifdef __cplusplus
@ -754,20 +757,61 @@ isunordered(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
// abs
#undef abs
#undef labs
#ifndef _LIBCPP_HAS_NO_LONG_LONG
#undef llabs
#endif
// MSVCRT already has the correct prototype in <stdlib.h> if __cplusplus is defined
#if !defined(_LIBCPP_MSVCRT) && !defined(__sun__) && !defined(_AIX)
inline _LIBCPP_INLINE_VISIBILITY long abs(long __x) _NOEXCEPT {
return ::labs(__x);
}
#ifndef _LIBCPP_HAS_NO_LONG_LONG
inline _LIBCPP_INLINE_VISIBILITY long long abs(long long __x) _NOEXCEPT {
return ::llabs(__x);
}
#endif // _LIBCPP_HAS_NO_LONG_LONG
#endif // !defined(_LIBCPP_MSVCRT) && !defined(__sun__) && !defined(_AIX)
#if !(defined(_AIX) || defined(__sun__))
inline _LIBCPP_INLINE_VISIBILITY
float
abs(float __lcpp_x) _NOEXCEPT {return ::fabsf(__lcpp_x);}
inline _LIBCPP_INLINE_VISIBILITY float abs(float __lcpp_x) _NOEXCEPT {
return ::fabsf(__lcpp_x);
}
inline _LIBCPP_INLINE_VISIBILITY
double
abs(double __lcpp_x) _NOEXCEPT {return ::fabs(__lcpp_x);}
inline _LIBCPP_INLINE_VISIBILITY double abs(double __lcpp_x) _NOEXCEPT {
return ::fabs(__lcpp_x);
}
inline _LIBCPP_INLINE_VISIBILITY
long double
abs(long double __lcpp_x) _NOEXCEPT {return ::fabsl(__lcpp_x);}
inline _LIBCPP_INLINE_VISIBILITY long double
abs(long double __lcpp_x) _NOEXCEPT {
return ::fabsl(__lcpp_x);
}
#endif // !(defined(_AIX) || defined(__sun__))
// div
#undef div
#undef ldiv
#ifndef _LIBCPP_HAS_NO_LONG_LONG
#undef lldiv
#endif
// MSVCRT already has the correct prototype in <stdlib.h> if __cplusplus is defined
#if !defined(_LIBCPP_MSVCRT) && !defined(__sun__) && !defined(_AIX)
inline _LIBCPP_INLINE_VISIBILITY ldiv_t div(long __x, long __y) _NOEXCEPT {
return ::ldiv(__x, __y);
}
#ifndef _LIBCPP_HAS_NO_LONG_LONG
inline _LIBCPP_INLINE_VISIBILITY lldiv_t div(long long __x,
long long __y) _NOEXCEPT {
return ::lldiv(__x, __y);
}
#endif // _LIBCPP_HAS_NO_LONG_LONG
#endif // _LIBCPP_MSVCRT / __sun__ / _AIX
// acos
#if !(defined(_AIX) || defined(__sun__))

34
libcxx/include/stdlib.h
View File

@ -7,12 +7,16 @@
//
//===----------------------------------------------------------------------===//
#if defined(__need_malloc_and_calloc)
#if defined(__need_malloc_and_calloc) || defined(_LIBCPP_STDLIB_INCLUDE_NEXT)
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif
#if defined(_LIBCPP_STDLIB_INCLUDE_NEXT)
#undef _LIBCPP_STDLIB_INCLUDE_NEXT
#endif
#include_next <stdlib.h>
#elif !defined(_LIBCPP_STDLIB_H)
@ -93,33 +97,7 @@ void *aligned_alloc(size_t alignment, size_t size); // C11
#include_next <stdlib.h>
#ifdef __cplusplus
extern "C++" {
#undef abs
#undef div
#undef labs
#undef ldiv
#ifndef _LIBCPP_HAS_NO_LONG_LONG
#undef llabs
#undef lldiv
#endif
// MSVCRT already has the correct prototype in <stdlib.h> if __cplusplus is defined
#if !defined(_LIBCPP_MSVCRT) && !defined(__sun__) && !defined(_AIX)
inline _LIBCPP_INLINE_VISIBILITY long abs( long __x) _NOEXCEPT {return labs(__x);}
#ifndef _LIBCPP_HAS_NO_LONG_LONG
inline _LIBCPP_INLINE_VISIBILITY long long abs(long long __x) _NOEXCEPT {return llabs(__x);}
#endif // _LIBCPP_HAS_NO_LONG_LONG
inline _LIBCPP_INLINE_VISIBILITY ldiv_t div( long __x, long __y) _NOEXCEPT {return ldiv(__x, __y);}
#ifndef _LIBCPP_HAS_NO_LONG_LONG
inline _LIBCPP_INLINE_VISIBILITY lldiv_t div(long long __x, long long __y) _NOEXCEPT {return lldiv(__x, __y);}
#endif // _LIBCPP_HAS_NO_LONG_LONG
#endif // _LIBCPP_MSVCRT / __sun__ / _AIX
} // extern "C++"
#include <math.h>
#endif // __cplusplus
#endif // _LIBCPP_STDLIB_H

42
libcxx/test/std/depr/depr.c.headers/math_h.pass.cpp
View File

@ -97,13 +97,45 @@ Ambiguous scalbn(Ambiguous, Ambiguous){ return Ambiguous(); }
Ambiguous tgamma(Ambiguous){ return Ambiguous(); }
Ambiguous trunc(Ambiguous){ return Ambiguous(); }
template <class T, class = decltype(::abs(std::declval<T>()))>
std::true_type has_abs_imp(int);
template <class T>
std::false_type has_abs_imp(...);
template <class T>
struct has_abs : decltype(has_abs_imp<T>(0)) {};
void test_abs()
{
static_assert((std::is_same<decltype(abs((float)0)), float>::value), "");
static_assert((std::is_same<decltype(abs((double)0)), double>::value), "");
static_assert((std::is_same<decltype(abs((long double)0)), long double>::value), "");
static_assert((std::is_same<decltype(abs(Ambiguous())), Ambiguous>::value), "");
assert(abs(-1.) == 1);
#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wabsolute-value"
#endif
static_assert((std::is_same<decltype(abs((float)0)), float>::value), "");
static_assert((std::is_same<decltype(abs((double)0)), double>::value), "");
static_assert(
(std::is_same<decltype(abs((long double)0)), long double>::value), "");
static_assert((std::is_same<decltype(abs((int)0)), int>::value), "");
static_assert((std::is_same<decltype(abs((long)0)), long>::value), "");
static_assert((std::is_same<decltype(abs((long long)0)), long long>::value),
"");
static_assert((std::is_same<decltype(abs((unsigned char)0)), int>::value),
"");
static_assert((std::is_same<decltype(abs((unsigned short)0)), int>::value),
"");
static_assert((std::is_same<decltype(abs(Ambiguous())), Ambiguous>::value),
"");
static_assert(!has_abs<unsigned>::value, "");
static_assert(!has_abs<unsigned long>::value, "");
static_assert(!has_abs<unsigned long long>::value, "");
#ifdef __clang__
#pragma clang diagnostic pop
#endif
assert(abs(-1.) == 1);
}
void test_acos()

51
libcxx/test/std/depr/depr.c.headers/stdlib_h.pass.cpp
View File

@ -10,6 +10,7 @@
#include <stdlib.h>
#include <type_traits>
#include <cassert>
#include "test_macros.h"
@ -63,6 +64,52 @@
#error RAND_MAX not defined
#endif
template <class T, class = decltype(::abs(std::declval<T>()))>
std::true_type has_abs_imp(int);
template <class T>
std::false_type has_abs_imp(...);
template <class T>
struct has_abs : decltype(has_abs_imp<T>(0)) {};
void test_abs() {
#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wabsolute-value"
#endif
static_assert((std::is_same<decltype(abs((float)0)), float>::value), "");
static_assert((std::is_same<decltype(abs((double)0)), double>::value), "");
static_assert(
(std::is_same<decltype(abs((long double)0)), long double>::value), "");
static_assert((std::is_same<decltype(abs((int)0)), int>::value), "");
static_assert((std::is_same<decltype(abs((long)0)), long>::value), "");
static_assert((std::is_same<decltype(abs((long long)0)), long long>::value),
"");
static_assert((std::is_same<decltype(abs((unsigned char)0)), int>::value),
"");
static_assert((std::is_same<decltype(abs((unsigned short)0)), int>::value),
"");
static_assert((std::is_same<decltype(abs((signed char)0)), int>::value),
"");
static_assert((std::is_same<decltype(abs((short)0)), int>::value),
"");
static_assert((std::is_same<decltype(abs((unsigned char)0)), int>::value),
"");
static_assert((std::is_same<decltype(abs((char)0)), int>::value),
"");
static_assert(!has_abs<unsigned>::value, "");
static_assert(!has_abs<unsigned long>::value, "");
static_assert(!has_abs<unsigned long long>::value, "");
static_assert(!has_abs<size_t>::value, "");
#ifdef __clang__
#pragma clang diagnostic pop
#endif
assert(abs(-1.) == 1);
}
int main(int, char**)
{
size_t s = 0; ((void)s);
@ -117,5 +164,7 @@ int main(int, char**)
static_assert((std::is_same<decltype(mbstowcs(pw,"",0)), size_t>::value), "");
static_assert((std::is_same<decltype(wcstombs(pc,pwc,0)), size_t>::value), "");
return 0;
test_abs();
return 0;
}

50
libcxx/test/std/language.support/support.runtime/cstdlib.pass.cpp
View File

@ -49,6 +49,52 @@ void test_div_struct() {
((void) obj);
};
template <class T, class = decltype(std::abs(std::declval<T>()))>
std::true_type has_abs_imp(int);
template <class T>
std::false_type has_abs_imp(...);
template <class T>
struct has_abs : decltype(has_abs_imp<T>(0)) {};
void test_abs() {
#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wabsolute-value"
#endif
static_assert((std::is_same<decltype(std::abs((float)0)), float>::value), "");
static_assert((std::is_same<decltype(std::abs((double)0)), double>::value), "");
static_assert(
(std::is_same<decltype(std::abs((long double)0)), long double>::value), "");
static_assert((std::is_same<decltype(std::abs((int)0)), int>::value), "");
static_assert((std::is_same<decltype(std::abs((long)0)), long>::value), "");
static_assert((std::is_same<decltype(std::abs((long long)0)), long long>::value),
"");
static_assert((std::is_same<decltype(std::abs((unsigned char)0)), int>::value),
"");
static_assert((std::is_same<decltype(std::abs((unsigned short)0)), int>::value),
"");
static_assert((std::is_same<decltype(std::abs((signed char)0)), int>::value),
"");
static_assert((std::is_same<decltype(std::abs((short)0)), int>::value),
"");
static_assert((std::is_same<decltype(std::abs((unsigned char)0)), int>::value),
"");
static_assert((std::is_same<decltype(std::abs((char)0)), int>::value),
"");
static_assert(!has_abs<unsigned>::value, "");
static_assert(!has_abs<unsigned long>::value, "");
static_assert(!has_abs<unsigned long long>::value, "");
static_assert(!has_abs<size_t>::value, "");
#ifdef __clang__
#pragma clang diagnostic pop
#endif
assert(std::abs(-1.) == 1);
}
int main(int, char**)
{
std::size_t s = 0;
@ -109,5 +155,7 @@ int main(int, char**)
static_assert((std::is_same<decltype(std::mbstowcs(pw,"",0)), std::size_t>::value), "");
static_assert((std::is_same<decltype(std::wcstombs(pc,pwc,0)), std::size_t>::value), "");
return 0;
test_abs();
return 0;
}

53
libcxx/test/std/numerics/c.math/cmath.pass.cpp
View File

@ -100,15 +100,54 @@ Ambiguous scalbn(Ambiguous, Ambiguous){ return Ambiguous(); }
Ambiguous tgamma(Ambiguous){ return Ambiguous(); }
Ambiguous trunc(Ambiguous){ return Ambiguous(); }
void test_abs()
{
static_assert((std::is_same<decltype(std::abs((float)0)), float>::value), "");
static_assert((std::is_same<decltype(std::abs((double)0)), double>::value), "");
static_assert((std::is_same<decltype(std::abs((long double)0)), long double>::value), "");
static_assert((std::is_same<decltype(abs(Ambiguous())), Ambiguous>::value), "");
assert(std::abs(-1.) == 1);
template <class T, class = decltype(std::abs(std::declval<T>()))>
std::true_type has_abs_imp(int);
template <class T>
std::false_type has_abs_imp(...);
template <class T>
struct has_abs : decltype(has_abs_imp<T>(0)) {};
void test_abs() {
#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wabsolute-value"
#endif
static_assert((std::is_same<decltype(std::abs((float)0)), float>::value), "");
static_assert((std::is_same<decltype(std::abs((double)0)), double>::value), "");
static_assert(
(std::is_same<decltype(std::abs((long double)0)), long double>::value), "");
static_assert((std::is_same<decltype(std::abs((int)0)), int>::value), "");
static_assert((std::is_same<decltype(std::abs((long)0)), long>::value), "");
static_assert((std::is_same<decltype(std::abs((long long)0)), long long>::value),
"");
static_assert((std::is_same<decltype(std::abs((unsigned char)0)), int>::value),
"");
static_assert((std::is_same<decltype(std::abs((unsigned short)0)), int>::value),
"");
static_assert((std::is_same<decltype(std::abs((signed char)0)), int>::value),
"");
static_assert((std::is_same<decltype(std::abs((short)0)), int>::value),
"");
static_assert((std::is_same<decltype(std::abs((unsigned char)0)), int>::value),
"");
static_assert((std::is_same<decltype(std::abs((char)0)), int>::value),
"");
static_assert((std::is_same<decltype(abs(Ambiguous())), Ambiguous>::value), "");
static_assert(!has_abs<unsigned>::value, "");
static_assert(!has_abs<unsigned long>::value, "");
static_assert(!has_abs<unsigned long long>::value, "");
static_assert(!has_abs<size_t>::value, "");
#ifdef __clang__
#pragma clang diagnostic pop
#endif
assert(std::abs(-1.) == 1);
}
void test_acos()
{
static_assert((std::is_same<decltype(std::acos((float)0)), float>::value), "");

2
libcxx/www/cxx1z_status.html
View File

@ -281,7 +281,7 @@
<tr><td><a href="https://wg21.link/LWG2492">2492</a></td><td>Clarify requirements for <tt>comp</tt></td><td>Kona</td><td>Complete</td></tr>
<tr><td><a href="https://wg21.link/LWG2495">2495</a></td><td>There is no such thing as an Exception Safety element</td><td>Kona</td><td>Complete</td></tr>
<tr><td></td><td></td><td></td><td></td></tr>
<tr><td><a href="https://wg21.link/LWG2192">2192</a></td><td>Validity and return type of <tt>std::abs(0u)</tt> is unclear</td><td>Jacksonville</td><td></td></tr>
<tr><td><a href="https://wg21.link/LWG2192">2192</a></td><td>Validity and return type of <tt>std::abs(0u)</tt> is unclear</td><td>Jacksonville</td><td>Complete</td></tr>
<tr><td><a href="https://wg21.link/LWG2276">2276</a></td><td>Missing requirement on <tt>std::promise::set_exception</tt></td><td>Jacksonville</td><td>Complete</td></tr>
<tr><td><a href="https://wg21.link/LWG2296">2296</a></td><td><tt>std::addressof</tt> should be <tt>constexpr</td><td>Jacksonville</td><td>Complete (Clang Only)</td></tr>
<tr><td><a href="https://wg21.link/LWG2450">2450</a></td><td><tt>(greater|less|greater_equal|less_equal)&lt;void&gt;</tt> do not yield a total order for pointers</td><td>Jacksonville</td><td>Complete</td></tr>