1 // <atomic> compatibility -*- C++ -*-
2 
3 // Copyright (C) 2008-2017 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&
get_atomic_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
test_and_set(memory_order)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
clear(memory_order)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
atomic_flag_test_and_set_explicit(__atomic_flag_base * __a,memory_order __m)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
atomic_flag_clear_explicit(__atomic_flag_base * __a,memory_order __m)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
__atomic_flag_wait_explicit(__atomic_flag_base * __a,memory_order __x)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*
__atomic_flag_for_address(const volatile void * __z)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
161