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/*
* 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 */
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