ceph/src/boost/tools/build/src/engine/boehm_gc/include/private/gc_locks.h

   1 /*
   2  * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
   3  * Copyright (c) 1991-1994 by Xerox Corporation.  All rights reserved.
   4  * Copyright (c) 1996-1999 by Silicon Graphics.  All rights reserved.
   5  * Copyright (c) 1999 by Hewlett-Packard Company. All rights reserved.
   6  *
   7  *
   8  * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
   9  * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
  10  *
  11  * Permission is hereby granted to use or copy this program
  12  * for any purpose,  provided the above notices are retained on all copies.
  13  * Permission to modify the code and to distribute modified code is granted,
  14  * provided the above notices are retained, and a notice that the code was
  15  * modified is included with the above copyright notice.
  16  */
  17
  18 #ifndef GC_LOCKS_H
  19 #define GC_LOCKS_H
  20
  21 /*
  22  * Mutual exclusion between allocator/collector routines.
  23  * Needed if there is more than one allocator thread.
  24  * DCL_LOCK_STATE declares any local variables needed by LOCK and UNLOCK.
  25  *
  26  * Note that I_HOLD_LOCK and I_DONT_HOLD_LOCK are used only positively
  27  * in assertions, and may return TRUE in the "dont know" case.
  28  */
  29 # ifdef THREADS
  30 #  include <atomic_ops.h>
  31
  32    void GC_noop1(word);
  33 #  ifdef PCR
  34 #    include <base/PCR_Base.h>
  35 #    include <th/PCR_Th.h>
  36      extern PCR_Th_ML GC_allocate_ml;
  37 #    define DCL_LOCK_STATE \
  38          PCR_ERes GC_fastLockRes; PCR_sigset_t GC_old_sig_mask
  39 #    define LOCK() PCR_Th_ML_Acquire(&GC_allocate_ml)
  40 #    define UNLOCK() PCR_Th_ML_Release(&GC_allocate_ml)
  41 #  endif
  42
  43 #  if !defined(AO_HAVE_test_and_set_acquire) && defined(GC_PTHREADS)
  44 #    define USE_PTHREAD_LOCKS
  45 #  endif
  46
  47 #  if defined(GC_WIN32_THREADS) && defined(GC_PTHREADS)
  48 #    define USE_PTHREAD_LOCKS
  49 #  endif
  50
  51 #  if defined(GC_WIN32_THREADS) && !defined(USE_PTHREAD_LOCKS)
  52 #    include <windows.h>
  53 #    define NO_THREAD (DWORD)(-1)
  54      extern DWORD GC_lock_holder;
  55      GC_API CRITICAL_SECTION GC_allocate_ml;
  56 #    ifdef GC_ASSERTIONS
  57 #        define UNCOND_LOCK() \
  58                 { EnterCriticalSection(&GC_allocate_ml); \
  59                   SET_LOCK_HOLDER(); }
  60 #        define UNCOND_UNLOCK() \
  61                 { GC_ASSERT(I_HOLD_LOCK()); UNSET_LOCK_HOLDER(); \
  62                   LeaveCriticalSection(&GC_allocate_ml); }
  63 #    else
  64 #      define UNCOND_LOCK() EnterCriticalSection(&GC_allocate_ml);
  65 #      define UNCOND_UNLOCK() LeaveCriticalSection(&GC_allocate_ml);
  66 #    endif /* !GC_ASSERTIONS */
  67 #    define SET_LOCK_HOLDER() GC_lock_holder = GetCurrentThreadId()
  68 #    define UNSET_LOCK_HOLDER() GC_lock_holder = NO_THREAD
  69 #    define I_HOLD_LOCK() (!GC_need_to_lock \
  70                            || GC_lock_holder == GetCurrentThreadId())
  71 #    define I_DONT_HOLD_LOCK() (!GC_need_to_lock \
  72                            || GC_lock_holder != GetCurrentThreadId())
  73 #  elif defined(GC_PTHREADS)
  74 #    include <pthread.h>
  75
  76      /* Posix allows pthread_t to be a struct, though it rarely is.     */
  77      /* Unfortunately, we need to use a pthread_t to index a data       */
  78      /* structure.  It also helps if comparisons don't involve a        */
  79      /* function call.  Hence we introduce platform-dependent macros    */
  80      /* to compare pthread_t ids and to map them to integers.           */
  81      /* the mapping to integers does not need to result in different    */
  82      /* integers for each thread, though that should be true as much    */
  83      /* as possible.                                                    */
  84      /* Refine to exclude platforms on which pthread_t is struct */
  85 #    if !defined(GC_WIN32_PTHREADS)
  86 #      define NUMERIC_THREAD_ID(id) ((unsigned long)(id))
  87 #      define THREAD_EQUAL(id1, id2) ((id1) == (id2))
  88 #      define NUMERIC_THREAD_ID_UNIQUE
  89 #    else
  90 #      if defined(GC_WIN32_PTHREADS)
  91 #        define NUMERIC_THREAD_ID(id) ((unsigned long)(id.p))
  92          /* Using documented internal details of win32_pthread library. */
  93          /* Faster than pthread_equal(). Should not change with         */
  94          /* future versions of win32_pthread library.                   */
  95 #        define THREAD_EQUAL(id1, id2) ((id1.p == id2.p) && (id1.x == id2.x))
  96 #        undef NUMERIC_THREAD_ID_UNIQUE
  97 #      else
  98          /* Generic definitions that always work, but will result in    */
  99          /* poor performance and weak assertion checking.               */
 100 #        define NUMERIC_THREAD_ID(id) 1l
 101 #        define THREAD_EQUAL(id1, id2) pthread_equal(id1, id2)
 102 #        undef NUMERIC_THREAD_ID_UNIQUE
 103 #      endif
 104 #    endif
 105 #    define NO_THREAD (-1l)
 106                 /* != NUMERIC_THREAD_ID(pthread_self()) for any thread */
 107
 108 #    if !defined(THREAD_LOCAL_ALLOC) && !defined(USE_PTHREAD_LOCKS)
 109       /* In the THREAD_LOCAL_ALLOC case, the allocation lock tends to   */
 110       /* be held for long periods, if it is held at all.  Thus spinning */
 111       /* and sleeping for fixed periods are likely to result in         */
 112       /* significant wasted time.  We thus rely mostly on queued locks. */
 113 #     define USE_SPIN_LOCK
 114       extern volatile AO_TS_t GC_allocate_lock;
 115       extern void GC_lock(void);
 116         /* Allocation lock holder.  Only set if acquired by client through */
 117         /* GC_call_with_alloc_lock.                                        */
 118 #     ifdef GC_ASSERTIONS
 119 #        define UNCOND_LOCK() \
 120                 { if (AO_test_and_set_acquire(&GC_allocate_lock) == AO_TS_SET) \
 121                         GC_lock(); \
 122                   SET_LOCK_HOLDER(); }
 123 #        define UNCOND_UNLOCK() \
 124                 { GC_ASSERT(I_HOLD_LOCK()); UNSET_LOCK_HOLDER(); \
 125                   AO_CLEAR(&GC_allocate_lock); }
 126 #     else
 127 #        define UNCOND_LOCK() \
 128                 { if (AO_test_and_set_acquire(&GC_allocate_lock) == AO_TS_SET) \
 129                         GC_lock(); }
 130 #        define UNCOND_UNLOCK() \
 131                 AO_CLEAR(&GC_allocate_lock)
 132 #     endif /* !GC_ASSERTIONS */
 133 #    else /* THREAD_LOCAL_ALLOC  || USE_PTHREAD_LOCKS */
 134 #      ifndef USE_PTHREAD_LOCKS
 135 #        define USE_PTHREAD_LOCKS
 136 #      endif
 137 #    endif /* THREAD_LOCAL_ALLOC || USE_PTHREAD_LOCK */
 138 #    ifdef USE_PTHREAD_LOCKS
 139 #      include <pthread.h>
 140        extern pthread_mutex_t GC_allocate_ml;
 141 #      ifdef GC_ASSERTIONS
 142 #        define UNCOND_LOCK() \
 143                 { GC_lock(); \
 144                   SET_LOCK_HOLDER(); }
 145 #        define UNCOND_UNLOCK() \
 146                 { GC_ASSERT(I_HOLD_LOCK()); UNSET_LOCK_HOLDER(); \
 147                   pthread_mutex_unlock(&GC_allocate_ml); }
 148 #      else /* !GC_ASSERTIONS */
 149 #        if defined(NO_PTHREAD_TRYLOCK)
 150 #          define UNCOND_LOCK() GC_lock();
 151 #        else /* !defined(NO_PTHREAD_TRYLOCK) */
 152 #        define UNCOND_LOCK() \
 153            { if (0 != pthread_mutex_trylock(&GC_allocate_ml)) GC_lock(); }
 154 #        endif
 155 #        define UNCOND_UNLOCK() pthread_mutex_unlock(&GC_allocate_ml)
 156 #      endif /* !GC_ASSERTIONS */
 157 #    endif /* USE_PTHREAD_LOCKS */
 158 #    define SET_LOCK_HOLDER() \
 159                 GC_lock_holder = NUMERIC_THREAD_ID(pthread_self())
 160 #    define UNSET_LOCK_HOLDER() GC_lock_holder = NO_THREAD
 161 #    define I_HOLD_LOCK() \
 162                 (!GC_need_to_lock || \
 163                  GC_lock_holder == NUMERIC_THREAD_ID(pthread_self()))
 164 #    ifndef NUMERIC_THREAD_ID_UNIQUE
 165 #      define I_DONT_HOLD_LOCK() 1  /* Conservatively say yes */
 166 #    else
 167 #      define I_DONT_HOLD_LOCK() \
 168                 (!GC_need_to_lock \
 169                  || GC_lock_holder != NUMERIC_THREAD_ID(pthread_self()))
 170 #    endif
 171      extern volatile GC_bool GC_collecting;
 172 #    define ENTER_GC() GC_collecting = 1;
 173 #    define EXIT_GC() GC_collecting = 0;
 174      extern void GC_lock(void);
 175      extern unsigned long GC_lock_holder;
 176 #    ifdef GC_ASSERTIONS
 177       extern unsigned long GC_mark_lock_holder;
 178 #    endif
 179 #  endif /* GC_PTHREADS with linux_threads.c implementation */
 180
 181
 182 # else /* !THREADS */
 183 #   define LOCK()
 184 #   define UNLOCK()
 185 #   define SET_LOCK_HOLDER()
 186 #   define UNSET_LOCK_HOLDER()
 187 #   define I_HOLD_LOCK() TRUE
 188 #   define I_DONT_HOLD_LOCK() TRUE
 189                 /* Used only in positive assertions or to test whether  */
 190                 /* we still need to acaquire the lock.  TRUE works in   */
 191                 /* either case.                                         */
 192 # endif /* !THREADS */
 193
 194 #if defined(UNCOND_LOCK) && !defined(LOCK)
 195      GC_API GC_bool GC_need_to_lock;
 196                 /* At least two thread running; need to lock.   */
 197 #    define LOCK() if (GC_need_to_lock) { UNCOND_LOCK(); }
 198 #    define UNLOCK() if (GC_need_to_lock) { UNCOND_UNLOCK(); }
 199 #endif
 200
 201 # ifndef ENTER_GC
 202 #   define ENTER_GC()
 203 #   define EXIT_GC()
 204 # endif
 205
 206 # ifndef DCL_LOCK_STATE
 207 #   define DCL_LOCK_STATE
 208 # endif
 209
 210 #endif /* GC_LOCKS_H */