atomic_0.h

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00001 // -*- C++ -*- header.
00002 
00003 // Copyright (C) 2008, 2009
00004 // Free Software Foundation, Inc.
00005 //
00006 // This file is part of the GNU ISO C++ Library.  This library is free
00007 // software; you can redistribute it and/or modify it under the
00008 // terms of the GNU General Public License as published by the
00009 // Free Software Foundation; either version 3, or (at your option)
00010 // any later version.
00011 
00012 // This library is distributed in the hope that it will be useful,
00013 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00014 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00015 // GNU General Public License for more details.
00016 
00017 // Under Section 7 of GPL version 3, you are granted additional
00018 // permissions described in the GCC Runtime Library Exception, version
00019 // 3.1, as published by the Free Software Foundation.
00020 
00021 // You should have received a copy of the GNU General Public License and
00022 // a copy of the GCC Runtime Library Exception along with this program;
00023 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
00024 // <http://www.gnu.org/licenses/>.
00025 
00026 /** @file bits/atomic_0.h
00027  *  This is an internal header file, included by other library headers.
00028  *  You should not attempt to use it directly.
00029  */
00030 
00031 #ifndef _GLIBCXX_ATOMIC_0_H
00032 #define _GLIBCXX_ATOMIC_0_H 1
00033 
00034 #pragma GCC system_header
00035 
00036 // _GLIBCXX_BEGIN_NAMESPACE(std)
00037 
00038   // 0 == __atomic0 == Never lock-free
00039 namespace __atomic0
00040 {
00041   struct atomic_flag;
00042 
00043   // Implementation specific defines.
00044 #define _ATOMIC_LOAD_(__a, __x)                        \
00045   ({ volatile __typeof__ _ATOMIC_MEMBER_* __p = &_ATOMIC_MEMBER_;      \
00046     volatile __atomic_flag_base* __g = __atomic_flag_for_address(__p);     \
00047     __atomic_flag_wait_explicit(__g, __x);                 \
00048     __typeof__ _ATOMIC_MEMBER_ __r = *__p;                 \
00049     atomic_flag_clear_explicit(__g, __x);                      \
00050     __r; })
00051 
00052 #define _ATOMIC_STORE_(__a, __m, __x)                      \
00053   ({ volatile __typeof__ _ATOMIC_MEMBER_* __p = &_ATOMIC_MEMBER_;      \
00054     __typeof__(__m) __v = (__m);                           \
00055     volatile __atomic_flag_base* __g = __atomic_flag_for_address(__p);     \
00056     __atomic_flag_wait_explicit(__g, __x);                 \
00057     *__p = __v;                                \
00058     atomic_flag_clear_explicit(__g, __x);                      \
00059     __v; })
00060 
00061 #define _ATOMIC_MODIFY_(__a, __o, __m, __x)                \
00062   ({ volatile __typeof__ _ATOMIC_MEMBER_* __p = &_ATOMIC_MEMBER_;      \
00063     __typeof__(__m) __v = (__m);                           \
00064     volatile __atomic_flag_base* __g = __atomic_flag_for_address(__p);     \
00065     __atomic_flag_wait_explicit(__g, __x);                 \
00066     __typeof__ _ATOMIC_MEMBER_ __r = *__p;                 \
00067     *__p __o __v;                                  \
00068     atomic_flag_clear_explicit(__g, __x);                      \
00069     __r; })
00070 
00071 #define _ATOMIC_CMPEXCHNG_(__a, __e, __m, __x)                 \
00072   ({ volatile __typeof__ _ATOMIC_MEMBER_* __p = &_ATOMIC_MEMBER_;      \
00073     __typeof__(__e) __q = (__e);                           \
00074     __typeof__(__m) __v = (__m);                           \
00075     bool __r;                                      \
00076     volatile __atomic_flag_base* __g = __atomic_flag_for_address(__p);     \
00077     __atomic_flag_wait_explicit(__g, __x);                 \
00078     __typeof__ _ATOMIC_MEMBER_ __t__ = *__p;                       \
00079     if (__t__ == *__q) { *__p = __v; __r = true; }             \
00080     else { *__q = __t__; __r = false; }                        \
00081     atomic_flag_clear_explicit(__g, __x);                      \
00082     __r; })
00083 
00084   /// atomic_flag
00085   struct atomic_flag : public __atomic_flag_base
00086   {
00087     atomic_flag() = default;
00088     ~atomic_flag() = default;
00089     atomic_flag(const atomic_flag&) = delete;
00090     atomic_flag& operator=(const atomic_flag&) = delete;
00091 
00092     // Conversion to ATOMIC_FLAG_INIT.
00093     atomic_flag(bool __i): __atomic_flag_base({ __i }) { }
00094 
00095     bool
00096     test_and_set(memory_order __m = memory_order_seq_cst) volatile;
00097 
00098     void
00099     clear(memory_order __m = memory_order_seq_cst) volatile;
00100   };
00101 
00102   /// 29.4.2, address types
00103   struct atomic_address
00104   {
00105   private:
00106     void* _M_i;
00107 
00108   public:
00109     atomic_address() = default;
00110     ~atomic_address() = default;
00111     atomic_address(const atomic_address&) = delete;
00112     atomic_address& operator=(const atomic_address&) = delete;
00113 
00114     atomic_address(void* __v) { _M_i = __v; }
00115 
00116     bool
00117     is_lock_free() const volatile
00118     { return false; }
00119 
00120     void
00121     store(void* __v, memory_order __m = memory_order_seq_cst) volatile
00122     {
00123       __glibcxx_assert(__m != memory_order_acquire);
00124       __glibcxx_assert(__m != memory_order_acq_rel);
00125       __glibcxx_assert(__m != memory_order_consume);
00126       _ATOMIC_STORE_(this, __v, __m);
00127     }
00128 
00129     void*
00130     load(memory_order __m = memory_order_seq_cst) const volatile
00131     {
00132       __glibcxx_assert(__m != memory_order_release);
00133       __glibcxx_assert(__m != memory_order_acq_rel);
00134       return _ATOMIC_LOAD_(this, __m);
00135     }
00136 
00137     void*
00138     exchange(void* __v, memory_order __m = memory_order_seq_cst) volatile
00139     { return _ATOMIC_MODIFY_(this, =, __v, __m); }
00140 
00141     bool
00142     compare_exchange_weak(void*& __v1, void* __v2, memory_order __m1,
00143               memory_order __m2) volatile
00144     {
00145       __glibcxx_assert(__m2 != memory_order_release);
00146       __glibcxx_assert(__m2 != memory_order_acq_rel);
00147       __glibcxx_assert(__m2 <= __m1);
00148       return _ATOMIC_CMPEXCHNG_(this, &__v1, __v2, __m1);
00149     }
00150 
00151     bool
00152     compare_exchange_weak(void*& __v1, void* __v2,
00153               memory_order __m = memory_order_seq_cst) volatile
00154     {
00155       return compare_exchange_weak(__v1, __v2, __m,
00156                    __calculate_memory_order(__m));
00157     }
00158 
00159     bool
00160     compare_exchange_strong(void*& __v1, void* __v2, memory_order __m1,
00161                 memory_order __m2) volatile
00162     {
00163       __glibcxx_assert(__m2 != memory_order_release);
00164       __glibcxx_assert(__m2 != memory_order_acq_rel);
00165       __glibcxx_assert(__m2 <= __m1);
00166       return _ATOMIC_CMPEXCHNG_(this, &__v1, __v2, __m1);
00167     }
00168 
00169     bool
00170     compare_exchange_strong(void*& __v1, void* __v2,
00171               memory_order __m = memory_order_seq_cst) volatile
00172     {
00173       return compare_exchange_strong(__v1, __v2, __m,
00174                      __calculate_memory_order(__m));
00175     }
00176 
00177     void*
00178     fetch_add(ptrdiff_t __d, memory_order __m = memory_order_seq_cst) volatile
00179     {
00180       void* volatile* __p = &(_M_i);
00181       volatile __atomic_flag_base* __g = __atomic_flag_for_address(__p);
00182       __atomic_flag_wait_explicit(__g, __m);
00183       void* __r = *__p;
00184       *__p = (void*)((char*)(*__p) + __d);
00185       atomic_flag_clear_explicit(__g, __m);
00186       return __r;
00187     }
00188 
00189     void*
00190     fetch_sub(ptrdiff_t __d, memory_order __m = memory_order_seq_cst) volatile
00191     {
00192       void* volatile* __p = &(_M_i);
00193       volatile __atomic_flag_base* __g = __atomic_flag_for_address(__p);
00194       __atomic_flag_wait_explicit(__g, __m);
00195       void* __r = *__p;
00196       *__p = (void*)((char*)(*__p) - __d);
00197       atomic_flag_clear_explicit(__g, __m);
00198       return __r;
00199     }
00200 
00201     operator void*() const volatile
00202     { return load(); }
00203 
00204     void*
00205     operator=(void* __v) // XXX volatile
00206     {
00207       store(__v);
00208       return __v;
00209     }
00210 
00211     void*
00212     operator+=(ptrdiff_t __d) volatile
00213     { return fetch_add(__d) + __d; }
00214 
00215     void*
00216     operator-=(ptrdiff_t __d) volatile
00217     { return fetch_sub(__d) - __d; }
00218   };
00219 
00220 
00221   // 29.3.1 atomic integral types
00222   // For each of the integral types, define atomic_[integral type] struct
00223   //
00224   // atomic_bool     bool
00225   // atomic_char     char
00226   // atomic_schar    signed char
00227   // atomic_uchar    unsigned char
00228   // atomic_short    short
00229   // atomic_ushort   unsigned short
00230   // atomic_int      int
00231   // atomic_uint     unsigned int
00232   // atomic_long     long
00233   // atomic_ulong    unsigned long
00234   // atomic_llong    long long
00235   // atomic_ullong   unsigned long long
00236   // atomic_char16_t char16_t
00237   // atomic_char32_t char32_t
00238   // atomic_wchar_t  wchar_t
00239 
00240   // Base type.
00241   // NB: Assuming _ITp is an integral scalar type that is 1, 2, 4, or 8 bytes,
00242   // since that is what GCC built-in functions for atomic memory access work on.
00243   template<typename _ITp>
00244     struct __atomic_base
00245     {
00246     private:
00247       typedef _ITp  __integral_type;
00248 
00249       __integral_type   _M_i;
00250 
00251     public:
00252       __atomic_base() = default;
00253       ~__atomic_base() = default;
00254       __atomic_base(const __atomic_base&) = delete;
00255       __atomic_base& operator=(const __atomic_base&) = delete;
00256 
00257       // Requires __integral_type convertible to _M_base._M_i.
00258       __atomic_base(__integral_type __i) { _M_i = __i; }
00259 
00260       operator __integral_type() const volatile
00261       { return load(); }
00262 
00263       __integral_type
00264       operator=(__integral_type __i) // XXX volatile
00265       {
00266     store(__i);
00267     return __i;
00268       }
00269 
00270       __integral_type
00271       operator++(int) volatile
00272       { return fetch_add(1); }
00273 
00274       __integral_type
00275       operator--(int) volatile
00276       { return fetch_sub(1); }
00277 
00278       __integral_type
00279       operator++() volatile
00280       { return fetch_add(1) + 1; }
00281 
00282       __integral_type
00283       operator--() volatile
00284       { return fetch_sub(1) - 1; }
00285 
00286       __integral_type
00287       operator+=(__integral_type __i) volatile
00288       { return fetch_add(__i) + __i; }
00289 
00290       __integral_type
00291       operator-=(__integral_type __i) volatile
00292       { return fetch_sub(__i) - __i; }
00293 
00294       __integral_type
00295       operator&=(__integral_type __i) volatile
00296       { return fetch_and(__i) & __i; }
00297 
00298       __integral_type
00299       operator|=(__integral_type __i) volatile
00300       { return fetch_or(__i) | __i; }
00301 
00302       __integral_type
00303       operator^=(__integral_type __i) volatile
00304       { return fetch_xor(__i) ^ __i; }
00305 
00306       bool
00307       is_lock_free() const volatile
00308       { return false; }
00309 
00310       void
00311       store(__integral_type __i,
00312         memory_order __m = memory_order_seq_cst) volatile
00313       {
00314     __glibcxx_assert(__m != memory_order_acquire);
00315     __glibcxx_assert(__m != memory_order_acq_rel);
00316     __glibcxx_assert(__m != memory_order_consume);
00317     _ATOMIC_STORE_(this, __i, __m);
00318       }
00319 
00320       __integral_type
00321       load(memory_order __m = memory_order_seq_cst) const volatile
00322       {
00323     __glibcxx_assert(__m != memory_order_release);
00324     __glibcxx_assert(__m != memory_order_acq_rel);
00325     return _ATOMIC_LOAD_(this, __m);
00326       }
00327 
00328       __integral_type
00329       exchange(__integral_type __i,
00330            memory_order __m = memory_order_seq_cst) volatile
00331       { return _ATOMIC_MODIFY_(this, =, __i, __m); }
00332 
00333       bool
00334       compare_exchange_weak(__integral_type& __i1, __integral_type __i2,
00335                 memory_order __m1, memory_order __m2) volatile
00336       {
00337     __glibcxx_assert(__m2 != memory_order_release);
00338     __glibcxx_assert(__m2 != memory_order_acq_rel);
00339     __glibcxx_assert(__m2 <= __m1);
00340     return _ATOMIC_CMPEXCHNG_(this, &__i1, __i2, __m1);
00341       }
00342 
00343       bool
00344       compare_exchange_weak(__integral_type& __i1, __integral_type __i2,
00345                 memory_order __m = memory_order_seq_cst) volatile
00346       {
00347     return compare_exchange_weak(__i1, __i2, __m,
00348                      __calculate_memory_order(__m));
00349       }
00350 
00351       bool
00352       compare_exchange_strong(__integral_type& __i1, __integral_type __i2,
00353                   memory_order __m1, memory_order __m2) volatile
00354       {
00355     __glibcxx_assert(__m2 != memory_order_release);
00356     __glibcxx_assert(__m2 != memory_order_acq_rel);
00357     __glibcxx_assert(__m2 <= __m1);
00358     return _ATOMIC_CMPEXCHNG_(this, &__i1, __i2, __m1);
00359       }
00360 
00361       bool
00362       compare_exchange_strong(__integral_type& __i1, __integral_type __i2,
00363                   memory_order __m = memory_order_seq_cst) volatile
00364       {
00365     return compare_exchange_strong(__i1, __i2, __m,
00366                        __calculate_memory_order(__m));
00367       }
00368 
00369       __integral_type
00370       fetch_add(__integral_type __i,
00371         memory_order __m = memory_order_seq_cst) volatile
00372       { return _ATOMIC_MODIFY_(this, +=, __i, __m); }
00373 
00374       __integral_type
00375       fetch_sub(__integral_type __i,
00376         memory_order __m = memory_order_seq_cst) volatile
00377       { return _ATOMIC_MODIFY_(this, -=, __i, __m); }
00378 
00379       __integral_type
00380       fetch_and(__integral_type __i,
00381         memory_order __m = memory_order_seq_cst) volatile
00382       { return _ATOMIC_MODIFY_(this, &=, __i, __m); }
00383 
00384       __integral_type
00385       fetch_or(__integral_type __i,
00386            memory_order __m = memory_order_seq_cst) volatile
00387       { return _ATOMIC_MODIFY_(this, |=, __i, __m); }
00388 
00389       __integral_type
00390       fetch_xor(__integral_type __i,
00391         memory_order __m = memory_order_seq_cst) volatile
00392       { return _ATOMIC_MODIFY_(this, ^=, __i, __m); }
00393     };
00394 
00395 
00396   /// atomic_bool
00397   // NB: No operators or fetch-operations for this type.
00398   struct atomic_bool
00399   {
00400   private:
00401     __atomic_base<bool> _M_base;
00402 
00403   public:
00404     atomic_bool() = default;
00405     ~atomic_bool() = default;
00406     atomic_bool(const atomic_bool&) = delete;
00407     atomic_bool& operator=(const atomic_bool&) = delete;
00408 
00409     atomic_bool(bool __i) : _M_base(__i) { }
00410 
00411     bool
00412     operator=(bool __i) // XXX volatile
00413     { return _M_base.operator=(__i); }
00414 
00415     operator bool() const volatile
00416     { return _M_base.load(); }
00417 
00418     bool
00419     is_lock_free() const volatile
00420     { return _M_base.is_lock_free(); }
00421 
00422     void
00423     store(bool __i, memory_order __m = memory_order_seq_cst) volatile
00424     { _M_base.store(__i, __m); }
00425 
00426     bool
00427     load(memory_order __m = memory_order_seq_cst) const volatile
00428     { return _M_base.load(__m); }
00429 
00430     bool
00431     exchange(bool __i, memory_order __m = memory_order_seq_cst) volatile
00432     { return _M_base.exchange(__i, __m); }
00433 
00434     bool
00435     compare_exchange_weak(bool& __i1, bool __i2, memory_order __m1,
00436               memory_order __m2) volatile
00437     { return _M_base.compare_exchange_weak(__i1, __i2, __m1, __m2); }
00438 
00439     bool
00440     compare_exchange_weak(bool& __i1, bool __i2,
00441               memory_order __m = memory_order_seq_cst) volatile
00442     { return _M_base.compare_exchange_weak(__i1, __i2, __m); }
00443 
00444     bool
00445     compare_exchange_strong(bool& __i1, bool __i2, memory_order __m1,
00446                 memory_order __m2) volatile
00447     { return _M_base.compare_exchange_strong(__i1, __i2, __m1, __m2); }
00448 
00449 
00450     bool
00451     compare_exchange_strong(bool& __i1, bool __i2,
00452                 memory_order __m = memory_order_seq_cst) volatile
00453     { return _M_base.compare_exchange_strong(__i1, __i2, __m); }
00454   };
00455 
00456 #undef _ATOMIC_LOAD_
00457 #undef _ATOMIC_STORE_
00458 #undef _ATOMIC_MODIFY_
00459 #undef _ATOMIC_CMPEXCHNG_
00460 } // namespace __atomic0
00461 
00462 // _GLIBCXX_END_NAMESPACE
00463 
00464 #endif

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