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

   1 // <atomic> compatibility -*- C++ -*-
   2
   3 // Copyright (C) 2008-2024 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 <atomic>
  26 #include <mutex>
  27
  28 // XXX GLIBCXX_ABI Deprecated
  29 // gcc-4.7.0
  30
  31 #ifdef _GLIBCXX_SHARED
  32
  33 #define LOGSIZE 4
  34
  35 namespace
  36 {
  37 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
  38   std::mutex&
  39   get_atomic_mutex()
  40   {
  41     static std::mutex atomic_mutex;
  42     return atomic_mutex;
  43   }
  44 #endif
  45
  46   std::__atomic_flag_base flag_table[ 1 << LOGSIZE ] =
  47     {
  48       ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT,
  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     };
  53 } // anonymous namespace
  54
  55 namespace std _GLIBCXX_VISIBILITY(default)
  56 {
  57 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  58
  59   namespace __atomic0
  60   {
  61
  62     struct atomic_flag : public __atomic_flag_base
  63     {
  64      bool
  65      test_and_set(memory_order) noexcept;
  66
  67      void
  68      clear(memory_order) noexcept;
  69     };
  70
  71     bool
  72     atomic_flag::test_and_set(memory_order) noexcept
  73     {
  74 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
  75       lock_guard<mutex> __lock(get_atomic_mutex());
  76 #endif
  77       bool result = _M_i;
  78       _M_i = true;
  79       return result;
  80     }
  81
  82     void
  83     atomic_flag::clear(memory_order) noexcept
  84     {
  85 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
  86       lock_guard<mutex> __lock(get_atomic_mutex());
  87 #endif
  88       _M_i = false;
  89     }
  90   } // namespace __atomic0
  91
  92   _GLIBCXX_BEGIN_EXTERN_C
  93
  94   bool
  95   atomic_flag_test_and_set_explicit(__atomic_flag_base* __a,
  96                                     memory_order __m) _GLIBCXX_NOTHROW
  97   {
  98     atomic_flag* d = static_cast<atomic_flag*>(__a);
  99     return d->test_and_set(__m);
 100   }
 101
 102   void
 103   atomic_flag_clear_explicit(__atomic_flag_base* __a,
 104                              memory_order __m) _GLIBCXX_NOTHROW
 105   {
 106     atomic_flag* d = static_cast<atomic_flag*>(__a);
 107     return d->clear(__m);
 108   }
 109
 110   void
 111   __atomic_flag_wait_explicit(__atomic_flag_base* __a,
 112                               memory_order __x) _GLIBCXX_NOTHROW
 113   {
 114     while (atomic_flag_test_and_set_explicit(__a, __x))
 115       { };
 116   }
 117
 118   _GLIBCXX_CONST __atomic_flag_base*
 119   __atomic_flag_for_address(const volatile void* __z) _GLIBCXX_NOTHROW
 120   {
 121     using guintptr_t = __UINTPTR_TYPE__;
 122     guintptr_t __u = reinterpret_cast<guintptr_t>(__z);
 123     __u += (__u >> 2) + (__u << 4);
 124     __u += (__u >> 7) + (__u << 5);
 125     __u += (__u >> 17) + (__u << 13);
 126     if (sizeof(guintptr_t) > 4)
 127       __u += (__u >> 31);
 128     __u &= ~((~guintptr_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