/libs/headers/gc/private/gc_locks.h
http://github.com/nddrylliog/ooc · C++ Header · 210 lines · 147 code · 14 blank · 49 comment · 36 complexity · 069cef609a8bc1a557b4ad17503e71e1 MD5 · raw file
- /*
- * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
- * Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
- * Copyright (c) 1996-1999 by Silicon Graphics. All rights reserved.
- * Copyright (c) 1999 by Hewlett-Packard Company. All rights reserved.
- *
- *
- * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
- * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
- *
- * Permission is hereby granted to use or copy this program
- * for any purpose, provided the above notices are retained on all copies.
- * Permission to modify the code and to distribute modified code is granted,
- * provided the above notices are retained, and a notice that the code was
- * modified is included with the above copyright notice.
- */
- #ifndef GC_LOCKS_H
- #define GC_LOCKS_H
- /*
- * Mutual exclusion between allocator/collector routines.
- * Needed if there is more than one allocator thread.
- * DCL_LOCK_STATE declares any local variables needed by LOCK and UNLOCK.
- *
- * Note that I_HOLD_LOCK and I_DONT_HOLD_LOCK are used only positively
- * in assertions, and may return TRUE in the "dont know" case.
- */
- # ifdef THREADS
- # include <atomic_ops.h>
- void GC_noop1(word);
- # ifdef PCR
- # include <base/PCR_Base.h>
- # include <th/PCR_Th.h>
- extern PCR_Th_ML GC_allocate_ml;
- # define DCL_LOCK_STATE \
- PCR_ERes GC_fastLockRes; PCR_sigset_t GC_old_sig_mask
- # define UNCOND_LOCK() PCR_Th_ML_Acquire(&GC_allocate_ml)
- # define UNCOND_UNLOCK() PCR_Th_ML_Release(&GC_allocate_ml)
- # endif
- # if !defined(AO_HAVE_test_and_set_acquire) && defined(GC_PTHREADS)
- # define USE_PTHREAD_LOCKS
- # endif
- # if defined(GC_WIN32_THREADS) && defined(GC_PTHREADS)
- # define USE_PTHREAD_LOCKS
- # endif
- # if defined(GC_WIN32_THREADS) && !defined(USE_PTHREAD_LOCKS)
- # include <windows.h>
- # define NO_THREAD (DWORD)(-1)
- extern DWORD GC_lock_holder;
- GC_API CRITICAL_SECTION GC_allocate_ml;
- # ifdef GC_ASSERTIONS
- # define UNCOND_LOCK() \
- { EnterCriticalSection(&GC_allocate_ml); \
- SET_LOCK_HOLDER(); }
- # define UNCOND_UNLOCK() \
- { GC_ASSERT(I_HOLD_LOCK()); UNSET_LOCK_HOLDER(); \
- LeaveCriticalSection(&GC_allocate_ml); }
- # else
- # define UNCOND_LOCK() EnterCriticalSection(&GC_allocate_ml);
- # define UNCOND_UNLOCK() LeaveCriticalSection(&GC_allocate_ml);
- # endif /* !GC_ASSERTIONS */
- # define SET_LOCK_HOLDER() GC_lock_holder = GetCurrentThreadId()
- # define UNSET_LOCK_HOLDER() GC_lock_holder = NO_THREAD
- # define I_HOLD_LOCK() (!GC_need_to_lock \
- || GC_lock_holder == GetCurrentThreadId())
- # define I_DONT_HOLD_LOCK() (!GC_need_to_lock \
- || GC_lock_holder != GetCurrentThreadId())
- # elif defined(GC_PTHREADS)
- # include <pthread.h>
-
- /* Posix allows pthread_t to be a struct, though it rarely is. */
- /* Unfortunately, we need to use a pthread_t to index a data */
- /* structure. It also helps if comparisons don't involve a */
- /* function call. Hence we introduce platform-dependent macros */
- /* to compare pthread_t ids and to map them to integers. */
- /* the mapping to integers does not need to result in different */
- /* integers for each thread, though that should be true as much */
- /* as possible. */
- /* Refine to exclude platforms on which pthread_t is struct */
- # if !defined(GC_WIN32_PTHREADS)
- # define NUMERIC_THREAD_ID(id) ((unsigned long)(id))
- # define THREAD_EQUAL(id1, id2) ((id1) == (id2))
- # define NUMERIC_THREAD_ID_UNIQUE
- # else
- # if defined(GC_WIN32_PTHREADS)
- # define NUMERIC_THREAD_ID(id) ((unsigned long)(id.p))
- /* Using documented internal details of win32_pthread library. */
- /* Faster than pthread_equal(). Should not change with */
- /* future versions of win32_pthread library. */
- # define THREAD_EQUAL(id1, id2) ((id1.p == id2.p) && (id1.x == id2.x))
- # undef NUMERIC_THREAD_ID_UNIQUE
- # else
- /* Generic definitions that always work, but will result in */
- /* poor performance and weak assertion checking. */
- # define NUMERIC_THREAD_ID(id) 1l
- # define THREAD_EQUAL(id1, id2) pthread_equal(id1, id2)
- # undef NUMERIC_THREAD_ID_UNIQUE
- # endif
- # endif
- # define NO_THREAD ((unsigned long)(-1l))
- /* != NUMERIC_THREAD_ID(pthread_self()) for any thread */
- # if !defined(THREAD_LOCAL_ALLOC) && !defined(USE_PTHREAD_LOCKS)
- /* In the THREAD_LOCAL_ALLOC case, the allocation lock tends to */
- /* be held for long periods, if it is held at all. Thus spinning */
- /* and sleeping for fixed periods are likely to result in */
- /* significant wasted time. We thus rely mostly on queued locks. */
- # define USE_SPIN_LOCK
- extern volatile AO_TS_t GC_allocate_lock;
- extern void GC_lock(void);
- /* Allocation lock holder. Only set if acquired by client through */
- /* GC_call_with_alloc_lock. */
- # ifdef GC_ASSERTIONS
- # define UNCOND_LOCK() \
- { if (AO_test_and_set_acquire(&GC_allocate_lock) == AO_TS_SET) \
- GC_lock(); \
- SET_LOCK_HOLDER(); }
- # define UNCOND_UNLOCK() \
- { GC_ASSERT(I_HOLD_LOCK()); UNSET_LOCK_HOLDER(); \
- AO_CLEAR(&GC_allocate_lock); }
- # else
- # define UNCOND_LOCK() \
- { if (AO_test_and_set_acquire(&GC_allocate_lock) == AO_TS_SET) \
- GC_lock(); }
- # define UNCOND_UNLOCK() \
- AO_CLEAR(&GC_allocate_lock)
- # endif /* !GC_ASSERTIONS */
- # else /* THREAD_LOCAL_ALLOC || USE_PTHREAD_LOCKS */
- # ifndef USE_PTHREAD_LOCKS
- # define USE_PTHREAD_LOCKS
- # endif
- # endif /* THREAD_LOCAL_ALLOC || USE_PTHREAD_LOCK */
- # ifdef USE_PTHREAD_LOCKS
- # include <pthread.h>
- extern pthread_mutex_t GC_allocate_ml;
- # ifdef GC_ASSERTIONS
- # define UNCOND_LOCK() \
- { GC_lock(); \
- SET_LOCK_HOLDER(); }
- # define UNCOND_UNLOCK() \
- { GC_ASSERT(I_HOLD_LOCK()); UNSET_LOCK_HOLDER(); \
- pthread_mutex_unlock(&GC_allocate_ml); }
- # else /* !GC_ASSERTIONS */
- # if defined(NO_PTHREAD_TRYLOCK)
- # define UNCOND_LOCK() GC_lock();
- # else /* !defined(NO_PTHREAD_TRYLOCK) */
- # define UNCOND_LOCK() \
- { if (0 != pthread_mutex_trylock(&GC_allocate_ml)) GC_lock(); }
- # endif
- # define UNCOND_UNLOCK() pthread_mutex_unlock(&GC_allocate_ml)
- # endif /* !GC_ASSERTIONS */
- # endif /* USE_PTHREAD_LOCKS */
- # define SET_LOCK_HOLDER() \
- GC_lock_holder = NUMERIC_THREAD_ID(pthread_self())
- # define UNSET_LOCK_HOLDER() GC_lock_holder = NO_THREAD
- # define I_HOLD_LOCK() \
- (!GC_need_to_lock || \
- GC_lock_holder == NUMERIC_THREAD_ID(pthread_self()))
- # ifndef NUMERIC_THREAD_ID_UNIQUE
- # define I_DONT_HOLD_LOCK() 1 /* Conservatively say yes */
- # else
- # define I_DONT_HOLD_LOCK() \
- (!GC_need_to_lock \
- || GC_lock_holder != NUMERIC_THREAD_ID(pthread_self()))
- # endif
- extern volatile GC_bool GC_collecting;
- # define ENTER_GC() GC_collecting = 1;
- # define EXIT_GC() GC_collecting = 0;
- extern void GC_lock(void);
- extern unsigned long GC_lock_holder;
- # ifdef GC_ASSERTIONS
- extern unsigned long GC_mark_lock_holder;
- # endif
- # endif /* GC_PTHREADS with linux_threads.c implementation */
- # else /* !THREADS */
- # define LOCK()
- # define UNLOCK()
- # define SET_LOCK_HOLDER()
- # define UNSET_LOCK_HOLDER()
- # define I_HOLD_LOCK() TRUE
- # define I_DONT_HOLD_LOCK() TRUE
- /* Used only in positive assertions or to test whether */
- /* we still need to acaquire the lock. TRUE works in */
- /* either case. */
- # endif /* !THREADS */
- #if defined(UNCOND_LOCK) && !defined(LOCK)
- GC_API GC_bool GC_need_to_lock;
- /* At least two thread running; need to lock. */
- # define LOCK() if (GC_need_to_lock) { UNCOND_LOCK(); }
- # define UNLOCK() if (GC_need_to_lock) { UNCOND_UNLOCK(); }
- #endif
- # ifndef ENTER_GC
- # define ENTER_GC()
- # define EXIT_GC()
- # endif
- # ifndef DCL_LOCK_STATE
- # define DCL_LOCK_STATE
- # endif
- #endif /* GC_LOCKS_H */