libstdc++-v3/src/mutex.cc

   1 // mutex -*- C++ -*-
   2
   3 // Copyright (C) 2008, 2009, 2010 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 <mutex>
  26
  27 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
  28 #ifndef _GLIBCXX_HAVE_TLS
  29 namespace
  30 {
  31   inline std::unique_lock<std::mutex>*&
  32   __get_once_functor_lock_ptr()
  33   {
  34     static std::unique_lock<std::mutex>* __once_functor_lock_ptr = 0;
  35     return __once_functor_lock_ptr;
  36   }
  37 }
  38 #endif
  39
  40 _GLIBCXX_BEGIN_NAMESPACE(std)
  41
  42 #ifdef _GLIBCXX_HAVE_TLS
  43   __thread void* __once_callable;
  44   __thread void (*__once_call)();
  45 #else
  46   // Explicit instantiation due to -fno-implicit-instantiation.
  47   template class function<void()>;
  48   function<void()> __once_functor;
  49
  50   mutex&
  51   __get_once_mutex()
  52   {
  53     static mutex once_mutex;
  54     return once_mutex;
  55   }
  56
  57   // code linked against ABI 3.4.12 and later uses this
  58   void
  59   __set_once_functor_lock_ptr(unique_lock<mutex>* __ptr)
  60   {
  61     __get_once_functor_lock_ptr() = __ptr;
  62   }
  63
  64   // unsafe - retained for compatibility with ABI 3.4.11
  65   unique_lock<mutex>&
  66   __get_once_functor_lock()
  67   {
  68     static unique_lock<mutex> once_functor_lock(__get_once_mutex(), defer_lock);
  69     return once_functor_lock;
  70   }
  71 #endif
  72
  73   extern "C"
  74   {
  75     void __once_proxy()
  76     {
  77 #ifndef _GLIBCXX_HAVE_TLS
  78       function<void()> __once_call = std::move(__once_functor);
  79       if (unique_lock<mutex>* __lock = __get_once_functor_lock_ptr())
  80       {
  81         // caller is using new ABI and provided lock ptr
  82         __get_once_functor_lock_ptr() = 0;
  83         __lock->unlock();
  84       }
  85       else
  86         __get_once_functor_lock().unlock();  // global lock
  87 #endif
  88       __once_call();
  89     }
  90   }
  91
  92 _GLIBCXX_END_NAMESPACE
  93
  94 // XXX GLIBCXX_ABI Deprecated
  95 // gcc-4.6.0
  96 // <mutex> export changes
  97 #if defined(_GLIBCXX_SYMVER_GNU) && defined(PIC) \
  98     && defined(_GLIBCXX_HAVE_AS_SYMVER_DIRECTIVE) \
  99     && defined(_GLIBCXX_HAVE_SYMVER_SYMBOL_RENAMING_RUNTIME_SUPPORT)
 100
 101 namespace __gnu_cxx
 102 {
 103   std::defer_lock_t defer_lock;
 104   std::try_to_lock_t try_to_lock;
 105   std::adopt_lock_t adopt_lock;
 106 }
 107
 108 #define _GLIBCXX_ASM_SYMVER(cur, old, version) \
 109    asm (".symver " #cur "," #old "@@" #version);
 110
 111 _GLIBCXX_ASM_SYMVER(_ZN9__gnu_cxx10adopt_lockE, _ZSt10adopt_lock, GLIBCXX_3.4.11)
 112 _GLIBCXX_ASM_SYMVER(_ZN9__gnu_cxx10defer_lockE, _ZSt10defer_lock, GLIBCXX_3.4.11)
 113 _GLIBCXX_ASM_SYMVER(_ZN9__gnu_cxx11try_to_lockE, _ZSt11try_to_lock, GLIBCXX_3.4.11)
 114
 115
 116 #endif
 117
 118 #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1