* [PATCH] Implement LWG 2192 and LWG 2294 for std::abs
@ 2016-10-10 12:32 Jonathan Wakely
0 siblings, 0 replies; only message in thread
From: Jonathan Wakely @ 2016-10-10 12:32 UTC (permalink / raw)
To: libstdc++, gcc-patches
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It looks like I forgot to send this patch to the lists last month.
This implements the requirements that all overloads of std::abs are
declared by either of <cmath> or <cstdlib>. This ensures that
including only one of those headers and calling std::abs doesn't cause
conversions from integers to floating point types, or vice versa.
* doc/xml/manual/intro.xml: Document LWG 2192 changes.
* doc/html/*: Regenerate.
* include/Makefile.am: Add bits/std_abs.h.
* include/Makefile.in: Regenerate.
* include/bits/std_abs.h: New header defining all required overloads
of std::abs in one place (LWG 2294).
* include/c_global/cmath (abs(double), abs(float), abs(long double)):
Move to bits/std_abs.h.
(abs<_Tp>(_Tp)): Remove.
* include/c_global/cstdlib (abs(long), abs(long long), abs(__int<N>)):
Move to bits/std_abs.h.
* testsuite/26_numerics/headers/cmath/dr2192.cc: New test.
* testsuite/26_numerics/headers/cmath/dr2192_neg.cc: New test.
* testsuite/26_numerics/headers/cstdlib/dr2192.cc: New test.
* testsuite/26_numerics/headers/cstdlib/dr2192_neg.cc: New test.
Tested on ppc64le and x86_64 GNU/Linux, and committed to trunk on 30
September.
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commit 9e441fcfca8a90e72a3cdbed42303dc2353b3da2
Author: redi <redi@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Fri Sep 30 16:07:43 2016 +0000
Implement LWG 2192 and LWG 2294 for std::abs
* doc/xml/manual/intro.xml: Document LWG 2192 changes.
* doc/html/*: Regenerate.
* include/Makefile.am: Add bits/std_abs.h.
* include/Makefile.in: Regenerate.
* include/bits/std_abs.h: New header defining all required overloads
of std::abs in one place (LWG 2294).
* include/c_global/cmath (abs(double), abs(float), abs(long double)):
Move to bits/std_abs.h.
(abs<_Tp>(_Tp)): Remove.
* include/c_global/cstdlib (abs(long), abs(long long), abs(__int<N>)):
Move to bits/std_abs.h.
* testsuite/26_numerics/headers/cmath/dr2192.cc: New test.
* testsuite/26_numerics/headers/cmath/dr2192_neg.cc: New test.
* testsuite/26_numerics/headers/cstdlib/dr2192.cc: New test.
* testsuite/26_numerics/headers/cstdlib/dr2192_neg.cc: New test.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@240660 138bc75d-0d04-0410-961f-82ee72b054a4
diff --git a/libstdc++-v3/doc/xml/manual/intro.xml b/libstdc++-v3/doc/xml/manual/intro.xml
index 238ab24..4747851 100644
--- a/libstdc++-v3/doc/xml/manual/intro.xml
+++ b/libstdc++-v3/doc/xml/manual/intro.xml
@@ -940,6 +940,13 @@ requirements of the license of GCC.
<listitem><para>Add <code>emplace</code> and <code>emplace_back</code> member functions.
</para></listitem></varlistentry>
+ <varlistentry><term><link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="../ext/lwg-defects.html#2192">2192</link>:
+ <emphasis>Validity and return type of <code>std::abs(0u)</code> is unclear</emphasis>
+ </term>
+ <listitem><para>Move all declarations to a common header and remove the
+ generic <code>abs</code> which accepted unsigned arguments.
+ </para></listitem></varlistentry>
+
<varlistentry><term><link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="../ext/lwg-defects.html#2196">2196</link>:
<emphasis>Specification of <code>is_*[copy/move]_[constructible/assignable]</code> unclear for non-referencable types</emphasis>
</term>
diff --git a/libstdc++-v3/include/Makefile.am b/libstdc++-v3/include/Makefile.am
index 7782258..4e63fbb 100644
--- a/libstdc++-v3/include/Makefile.am
+++ b/libstdc++-v3/include/Makefile.am
@@ -159,6 +159,7 @@ bits_headers = \
${bits_srcdir}/shared_ptr_base.h \
${bits_srcdir}/slice_array.h \
${bits_srcdir}/sstream.tcc \
+ ${bits_srcdir}/std_abs.h \
${bits_srcdir}/std_mutex.h \
${bits_srcdir}/stl_algo.h \
${bits_srcdir}/stl_algobase.h \
diff --git a/libstdc++-v3/include/bits/std_abs.h b/libstdc++-v3/include/bits/std_abs.h
new file mode 100644
index 0000000..ab0f980
--- /dev/null
+++ b/libstdc++-v3/include/bits/std_abs.h
@@ -0,0 +1,107 @@
+// -*- C++ -*- C library enhancements header.
+
+// Copyright (C) 2016 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library. This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/bits/std_abs.h
+ * This is an internal header file, included by other library headers.
+ * Do not attempt to use it directly. @headername{cmath, cstdlib}
+ */
+
+#ifndef _GLIBCXX_BITS_STD_ABS_H
+#define _GLIBCXX_BITS_STD_ABS_H
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+
+#define _GLIBCXX_INCLUDE_NEXT_C_HEADERS
+#include_next <stdlib.h>
+#ifdef __CORRECT_ISO_CPP_MATH_H_PROTO
+# include_next <math.h>
+#endif
+#undef _GLIBCXX_INCLUDE_NEXT_C_HEADERS
+
+#undef abs
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+ using ::abs;
+
+#ifndef __CORRECT_ISO_CPP_STDLIB_H_PROTO
+ inline long
+ abs(long __i) { return __builtin_labs(__i); }
+#endif
+
+#ifdef _GLIBCXX_USE_LONG_LONG
+ inline long long
+ abs(long long __x) { return __builtin_llabs (__x); }
+#endif
+
+// _GLIBCXX_RESOLVE_LIB_DEFECTS
+// 2192. Validity and return type of std::abs(0u) is unclear
+// 2294. <cstdlib> should declare abs(double)
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+ inline _GLIBCXX_CONSTEXPR double
+ abs(double __x)
+ { return __builtin_fabs(__x); }
+
+ inline _GLIBCXX_CONSTEXPR float
+ abs(float __x)
+ { return __builtin_fabsf(__x); }
+
+ inline _GLIBCXX_CONSTEXPR long double
+ abs(long double __x)
+ { return __builtin_fabsl(__x); }
+#endif
+
+#if defined(__GLIBCXX_TYPE_INT_N_0)
+ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_0
+ abs(__GLIBCXX_TYPE_INT_N_0 __x) { return __x >= 0 ? __x : -__x; }
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_1)
+ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_1
+ abs(__GLIBCXX_TYPE_INT_N_1 __x) { return __x >= 0 ? __x : -__x; }
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_2)
+ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_2
+ abs(__GLIBCXX_TYPE_INT_N_2 __x) { return __x >= 0 ? __x : -__x; }
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_3)
+ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_3
+ abs(__GLIBCXX_TYPE_INT_N_3 __x) { return __x >= 0 ? __x : -__x; }
+#endif
+
+#if !defined(__STRICT_ANSI__) && defined(_GLIBCXX_USE_FLOAT128)
+ inline _GLIBCXX_CONSTEXPR
+ __float128
+ abs(__float128 __x)
+ { return __x < 0 ? -__x : __x; }
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif // _GLIBCXX_BITS_STD_ABS_H
diff --git a/libstdc++-v3/include/c_global/cmath b/libstdc++-v3/include/c_global/cmath
index 0e7c4ad..24ce811 100644
--- a/libstdc++-v3/include/c_global/cmath
+++ b/libstdc++-v3/include/c_global/cmath
@@ -44,12 +44,12 @@
#define _GLIBCXX_INCLUDE_NEXT_C_HEADERS
#include_next <math.h>
#undef _GLIBCXX_INCLUDE_NEXT_C_HEADERS
+#include <bits/std_abs.h>
#ifndef _GLIBCXX_CMATH
#define _GLIBCXX_CMATH 1
// Get rid of those macros defined in <math.h> in lieu of real functions.
-#undef abs
#undef div
#undef acos
#undef asin
@@ -80,29 +80,6 @@ namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
-#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
- inline _GLIBCXX_CONSTEXPR double
- abs(double __x)
- { return __builtin_fabs(__x); }
-#endif
-
-#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
- inline _GLIBCXX_CONSTEXPR float
- abs(float __x)
- { return __builtin_fabsf(__x); }
-
- inline _GLIBCXX_CONSTEXPR long double
- abs(long double __x)
- { return __builtin_fabsl(__x); }
-#endif
-
- template<typename _Tp>
- inline _GLIBCXX_CONSTEXPR
- typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
- double>::__type
- abs(_Tp __x)
- { return __builtin_fabs(__x); }
-
using ::acos;
#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
diff --git a/libstdc++-v3/include/c_global/cstdlib b/libstdc++-v3/include/c_global/cstdlib
index 1ba5fb7..15733df 100644
--- a/libstdc++-v3/include/c_global/cstdlib
+++ b/libstdc++-v3/include/c_global/cstdlib
@@ -74,10 +74,10 @@ namespace std
#define _GLIBCXX_INCLUDE_NEXT_C_HEADERS
#include_next <stdlib.h>
#undef _GLIBCXX_INCLUDE_NEXT_C_HEADERS
+#include <bits/std_abs.h>
// Get rid of those macros defined in <stdlib.h> in lieu of real functions.
#undef abort
-#undef abs
#undef atexit
#if __cplusplus >= 201103L
# ifdef _GLIBCXX_HAVE_AT_QUICK_EXIT
@@ -125,7 +125,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
using ::ldiv_t;
using ::abort;
- using ::abs;
using ::atexit;
#if __cplusplus >= 201103L
# ifdef _GLIBCXX_HAVE_AT_QUICK_EXIT
@@ -168,35 +167,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
#endif // _GLIBCXX_USE_WCHAR_T
#ifndef __CORRECT_ISO_CPP_STDLIB_H_PROTO
- inline long
- abs(long __i) { return __builtin_labs(__i); }
-
inline ldiv_t
div(long __i, long __j) { return ldiv(__i, __j); }
#endif
-#ifdef _GLIBCXX_USE_LONG_LONG
- inline long long
- abs(long long __x) { return __builtin_llabs (__x); }
-#endif
-
-#if defined(__GLIBCXX_TYPE_INT_N_0)
- inline __GLIBCXX_TYPE_INT_N_0
- abs(__GLIBCXX_TYPE_INT_N_0 __x) { return __x >= 0 ? __x : -__x; }
-#endif
-#if defined(__GLIBCXX_TYPE_INT_N_1)
- inline __GLIBCXX_TYPE_INT_N_1
- abs(__GLIBCXX_TYPE_INT_N_1 __x) { return __x >= 0 ? __x : -__x; }
-#endif
-#if defined(__GLIBCXX_TYPE_INT_N_2)
- inline __GLIBCXX_TYPE_INT_N_2
- abs(__GLIBCXX_TYPE_INT_N_2 __x) { return __x >= 0 ? __x : -__x; }
-#endif
-#if defined(__GLIBCXX_TYPE_INT_N_3)
- inline __GLIBCXX_TYPE_INT_N_3
- abs(__GLIBCXX_TYPE_INT_N_3 __x) { return __x >= 0 ? __x : -__x; }
-#endif
-
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
diff --git a/libstdc++-v3/testsuite/26_numerics/headers/cmath/dr2192.cc b/libstdc++-v3/testsuite/26_numerics/headers/cmath/dr2192.cc
new file mode 100644
index 0000000..b8d13cd
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/headers/cmath/dr2192.cc
@@ -0,0 +1,39 @@
+// Copyright (C) 2016 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library. This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3. If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-do compile { target c++11 } }
+
+// NB: Don't include any other headers in this file.
+// LWG 2192 requires <cmath> to declare overloads for integral types.
+#include <cmath>
+
+template<typename, typename> struct is_same { enum { value = 0 }; };
+template<typename T> struct is_same<T, T> { enum { value = 1 }; };
+
+template<typename T, typename U = T>
+ constexpr bool check(T val) {
+ return is_same<decltype(std::abs(val)), U>::value;
+ }
+
+// Unsigned arguments that promote to int are valid:
+static_assert( check<short, int>(1), "abs((short)1) returns int" );
+static_assert( check<unsigned short, int>(1),
+ "abs((unsigned short)1) returns int" );
+
+static_assert( check(1), "abs(1) returns int" );
+static_assert( check(1l), "abs(1l) returns long" );
+static_assert( check(1ll), "abs(1ll) returns long long" );
diff --git a/libstdc++-v3/testsuite/26_numerics/headers/cmath/dr2192_neg.cc b/libstdc++-v3/testsuite/26_numerics/headers/cmath/dr2192_neg.cc
new file mode 100644
index 0000000..bda980a
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/headers/cmath/dr2192_neg.cc
@@ -0,0 +1,29 @@
+// Copyright (C) 2016 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library. This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3. If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-do compile { target c++11 } }
+
+// NB: Don't include any other headers in this file.
+// LWG 2192 requires abs to be ill-formed for unsigned arguments.
+#include <cmath>
+
+void test()
+{
+ std::abs(0u); // { dg-error "ambiguous" }
+ std::abs(0lu); // { dg-error "ambiguous" }
+ std::abs(0llu); // { dg-error "ambiguous" }
+}
diff --git a/libstdc++-v3/testsuite/26_numerics/headers/cstdlib/dr2192.cc b/libstdc++-v3/testsuite/26_numerics/headers/cstdlib/dr2192.cc
new file mode 100644
index 0000000..312e907
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/headers/cstdlib/dr2192.cc
@@ -0,0 +1,34 @@
+// Copyright (C) 2016 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library. This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3. If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-do compile { target c++11 } }
+
+// NB: Don't include any other headers in this file.
+// LWG 2192 requires <cstdlib> to declare overloads for floating point types.
+#include <cstdlib>
+
+template<typename, typename> struct is_same { enum { value = 0 }; };
+template<typename T> struct is_same<T, T> { enum { value = 1 }; };
+
+template<typename T>
+ constexpr bool check(T val) {
+ return is_same<decltype(std::abs(val)), T>::value;
+ }
+
+static_assert( check(1.f), "abs(1.f) returns float" );
+static_assert( check(1.), "abs(1.) returns double" );
+static_assert( check(1.l), "abs(1.l) returns long double" );
diff --git a/libstdc++-v3/testsuite/26_numerics/headers/cstdlib/dr2192_neg.cc b/libstdc++-v3/testsuite/26_numerics/headers/cstdlib/dr2192_neg.cc
new file mode 100644
index 0000000..9f0046f
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/headers/cstdlib/dr2192_neg.cc
@@ -0,0 +1,29 @@
+// Copyright (C) 2016 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library. This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3. If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-do compile { target c++11 } }
+
+// NB: Don't include any other headers in this file.
+// LWG 2192 requires abs to be ill-formed for unsigned arguments.
+#include <cstdlib>
+
+void test()
+{
+ std::abs(0u); // { dg-error "ambiguous" }
+ std::abs(0lu); // { dg-error "ambiguous" }
+ std::abs(0llu); // { dg-error "ambiguous" }
+}
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2016-10-10 12:32 [PATCH] Implement LWG 2192 and LWG 2294 for std::abs Jonathan Wakely
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