contrib/gcc-8.0/libstdc++-v3/src/c++11/compatibility-atomic-c++0x.cc

   1 // <atomic> compatibility -*- C++ -*-
   2
   3 // Copyright (C) 2008-2018 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // Under Section 7 of GPL version 3, you are granted additional
  17 // permissions described in the GCC Runtime Library Exception, version
  18 // 3.1, as published by the Free Software Foundation.
  19
  20 // You should have received a copy of the GNU General Public License and
  21 // a copy of the GCC Runtime Library Exception along with this program;
  22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 // <http://www.gnu.org/licenses/>.
  24
  25 #include "gstdint.h"
  26 #include <atomic>
  27 #include <mutex>
  28
  29 // XXX GLIBCXX_ABI Deprecated
  30 // gcc-4.7.0
  31
  32 #ifdef _GLIBCXX_SHARED
  33
  34 #define LOGSIZE 4
  35
  36 namespace
  37 {
  38 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
  39   std::mutex&
  40   get_atomic_mutex()
  41   {
  42     static std::mutex atomic_mutex;
  43     return atomic_mutex;
  44   }
  45 #endif
  46
  47   std::__atomic_flag_base flag_table[ 1 << LOGSIZE ] =
  48     {
  49       ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT,
  50       ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT,
  51       ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT,
  52       ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT,
  53     };
  54 } // anonymous namespace
  55
  56 namespace std _GLIBCXX_VISIBILITY(default)
  57 {
  58 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  59
  60   namespace __atomic0
  61   {
  62
  63     struct atomic_flag : public __atomic_flag_base
  64     {
  65      bool
  66      test_and_set(memory_order) noexcept;
  67
  68      void
  69      clear(memory_order) noexcept;
  70     };
  71
  72     bool
  73     atomic_flag::test_and_set(memory_order) noexcept
  74     {
  75 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
  76       lock_guard<mutex> __lock(get_atomic_mutex());
  77 #endif
  78       bool result = _M_i;
  79       _M_i = true;
  80       return result;
  81     }
  82
  83     void
  84     atomic_flag::clear(memory_order) noexcept
  85     {
  86 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
  87       lock_guard<mutex> __lock(get_atomic_mutex());
  88 #endif
  89       _M_i = false;
  90     }
  91   } // namespace __atomic0
  92
  93   _GLIBCXX_BEGIN_EXTERN_C
  94
  95   bool
  96   atomic_flag_test_and_set_explicit(__atomic_flag_base* __a,
  97                                     memory_order __m) _GLIBCXX_NOTHROW
  98   {
  99     atomic_flag* d = static_cast<atomic_flag*>(__a);
 100     return d->test_and_set(__m);
 101   }
 102
 103   void
 104   atomic_flag_clear_explicit(__atomic_flag_base* __a,
 105                              memory_order __m) _GLIBCXX_NOTHROW
 106   {
 107     atomic_flag* d = static_cast<atomic_flag*>(__a);
 108     return d->clear(__m);
 109   }
 110
 111   void
 112   __atomic_flag_wait_explicit(__atomic_flag_base* __a,
 113                               memory_order __x) _GLIBCXX_NOTHROW
 114   {
 115     while (atomic_flag_test_and_set_explicit(__a, __x))
 116       { };
 117   }
 118
 119   _GLIBCXX_CONST __atomic_flag_base*
 120   __atomic_flag_for_address(const volatile void* __z) _GLIBCXX_NOTHROW
 121   {
 122     uintptr_t __u = reinterpret_cast<uintptr_t>(__z);
 123     __u += (__u >> 2) + (__u << 4);
 124     __u += (__u >> 7) + (__u << 5);
 125     __u += (__u >> 17) + (__u << 13);
 126     if (sizeof(uintptr_t) > 4)
 127       __u += (__u >> 31);
 128     __u &= ~((~uintptr_t(0)) << LOGSIZE);
 129     return flag_table + __u;
 130   }
 131
 132   _GLIBCXX_END_EXTERN_C
 133
 134 _GLIBCXX_END_NAMESPACE_VERSION
 135 } // namespace std
 136
 137 #endif
 138
 139 // XXX GLIBCXX_ABI Deprecated
 140 // gcc-4.5.0
 141 // <atomic> signature changes
 142
 143 // The rename syntax for default exported names is
 144 //   asm (".symver name1,exportedname@GLIBCXX_3.4")
 145 //   asm (".symver name2,exportedname@@GLIBCXX_3.4.5")
 146 // In the future, GLIBCXX_ABI > 6 should remove all uses of
 147 // _GLIBCXX_*_SYMVER macros in this file.
 148
 149 #if defined(_GLIBCXX_SYMVER_GNU) && defined(_GLIBCXX_SHARED) \
 150     && defined(_GLIBCXX_HAVE_AS_SYMVER_DIRECTIVE) \
 151     && defined(_GLIBCXX_HAVE_SYMVER_SYMBOL_RENAMING_RUNTIME_SUPPORT)
 152
 153 #define _GLIBCXX_ASM_SYMVER(cur, old, version) \
 154    asm (".symver " #cur "," #old "@@" #version);
 155
 156 _GLIBCXX_ASM_SYMVER(_ZNSt9__atomic011atomic_flag5clearESt12memory_order, _ZNVSt9__atomic011atomic_flag5clearESt12memory_order, GLIBCXX_3.4.11)
 157
 158 _GLIBCXX_ASM_SYMVER(_ZNSt9__atomic011atomic_flag12test_and_setESt12memory_order, _ZNVSt9__atomic011atomic_flag12test_and_setESt12memory_order, GLIBCXX_3.4.11)
 159
 160 #endif