/*
* Mutual exclusion between allocator/collector routines.
* Needed if there is more than one allocator thread.
- * FASTLOCK() is assumed to try to acquire the lock in a cheap and
- * dirty way that is acceptable for a few instructions, e.g. by
- * inhibiting preemption. This is assumed to have succeeded only
- * if a subsequent call to FASTLOCK_SUCCEEDED() returns TRUE.
- * FASTUNLOCK() is called whether or not FASTLOCK_SUCCEEDED().
- * If signals cannot be tolerated with the FASTLOCK held, then
- * FASTLOCK should disable signals. The code executed under
- * FASTLOCK is otherwise immune to interruption, provided it is
- * not restarted.
- * DCL_LOCK_STATE declares any local variables needed by LOCK and UNLOCK
- * and/or DISABLE_SIGNALS and ENABLE_SIGNALS and/or FASTLOCK.
- * (There is currently no equivalent for FASTLOCK.)
+ * DCL_LOCK_STATE declares any local variables needed by LOCK and UNLOCK.
*
- * In the PARALLEL_MARK case, we also need to define a number of
- * other inline finctions here:
- * GC_bool GC_compare_and_exchange( volatile GC_word *addr,
- * GC_word old, GC_word new )
- * GC_word GC_atomic_add( volatile GC_word *addr, GC_word how_much )
- * void GC_memory_barrier( )
- *
+ * 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
- void GC_noop1 GC_PROTO((word));
-# ifdef PCR_OBSOLETE /* Faster, but broken with multiple lwp's */
-# include "th/PCR_Th.h"
-# include "th/PCR_ThCrSec.h"
- extern struct PCR_Th_MLRep GC_allocate_ml;
-# define DCL_LOCK_STATE PCR_sigset_t GC_old_sig_mask
-# define LOCK() PCR_Th_ML_Acquire(&GC_allocate_ml)
-# define UNLOCK() PCR_Th_ML_Release(&GC_allocate_ml)
-# define UNLOCK() PCR_Th_ML_Release(&GC_allocate_ml)
-# define FASTLOCK() PCR_ThCrSec_EnterSys()
- /* Here we cheat (a lot): */
-# define FASTLOCK_SUCCEEDED() (*(int *)(&GC_allocate_ml) == 0)
- /* TRUE if nobody currently holds the lock */
-# define FASTUNLOCK() PCR_ThCrSec_ExitSys()
-# endif
+# include <atomic_ops.h>
+
+ GC_API void GC_CALL 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 LOCK() PCR_Th_ML_Acquire(&GC_allocate_ml)
-# define UNLOCK() PCR_Th_ML_Release(&GC_allocate_ml)
-# define FASTLOCK() (GC_fastLockRes = PCR_Th_ML_Try(&GC_allocate_ml))
-# define FASTLOCK_SUCCEEDED() (GC_fastLockRes == PCR_ERes_okay)
-# define FASTUNLOCK() {\
- if( FASTLOCK_SUCCEEDED() ) PCR_Th_ML_Release(&GC_allocate_ml); }
-# endif
-# ifdef SRC_M3
- extern GC_word RT0u__inCritical;
-# define LOCK() RT0u__inCritical++
-# define UNLOCK() RT0u__inCritical--
-# endif
-# ifdef GC_SOLARIS_THREADS
-# include <thread.h>
-# include <signal.h>
- extern mutex_t GC_allocate_ml;
-# define LOCK() mutex_lock(&GC_allocate_ml);
-# define UNLOCK() mutex_unlock(&GC_allocate_ml);
-# endif
-
-/* Try to define GC_TEST_AND_SET and a matching GC_CLEAR for spin lock */
-/* acquisition and release. We need this for correct operation of the */
-/* incremental GC. */
-# ifdef __GNUC__
-# if defined(I386)
- inline static int GC_test_and_set(volatile unsigned int *addr) {
- int oldval;
- /* Note: the "xchg" instruction does not need a "lock" prefix */
- __asm__ __volatile__("xchgl %0, %1"
- : "=r"(oldval), "=m"(*(addr))
- : "0"(1), "m"(*(addr)) : "memory");
- return oldval;
- }
-# define GC_TEST_AND_SET_DEFINED
-# endif
-# if defined(IA64)
-# if defined(__INTEL_COMPILER)
-# include <ia64intrin.h>
-# endif
- inline static int GC_test_and_set(volatile unsigned int *addr) {
- long oldval, n = 1;
-# ifndef __INTEL_COMPILER
- __asm__ __volatile__("xchg4 %0=%1,%2"
- : "=r"(oldval), "=m"(*addr)
- : "r"(n), "1"(*addr) : "memory");
-# else
- oldval = _InterlockedExchange(addr, n);
-# endif
- return oldval;
- }
-# define GC_TEST_AND_SET_DEFINED
- /* Should this handle post-increment addressing?? */
- inline static void GC_clear(volatile unsigned int *addr) {
-# ifndef __INTEL_COMPILER
- __asm__ __volatile__("st4.rel %0=r0" : "=m" (*addr) : : "memory");
-# else
- /* there is no st4 but I can use xchg I hope */
- _InterlockedExchange(addr, 0);
-# endif
- }
-# define GC_CLEAR_DEFINED
-# endif
-# ifdef SPARC
- inline static int GC_test_and_set(volatile unsigned int *addr) {
- int oldval;
-
- __asm__ __volatile__("ldstub %1,%0"
- : "=r"(oldval), "=m"(*addr)
- : "m"(*addr) : "memory");
- return oldval;
- }
-# define GC_TEST_AND_SET_DEFINED
-# endif
-# ifdef M68K
- /* Contributed by Tony Mantler. I'm not sure how well it was */
- /* tested. */
- inline static int GC_test_and_set(volatile unsigned int *addr) {
- char oldval; /* this must be no longer than 8 bits */
-
- /* The return value is semi-phony. */
- /* 'tas' sets bit 7 while the return */
- /* value pretends bit 0 was set */
- __asm__ __volatile__(
- "tas %1@; sne %0; negb %0"
- : "=d" (oldval)
- : "a" (addr) : "memory");
- return oldval;
- }
-# define GC_TEST_AND_SET_DEFINED
-# endif
-# if defined(POWERPC)
- inline static int GC_test_and_set(volatile unsigned int *addr) {
- int oldval;
- int temp = 1; /* locked value */
-
- __asm__ __volatile__(
- "1:\tlwarx %0,0,%3\n" /* load and reserve */
- "\tcmpwi %0, 0\n" /* if load is */
- "\tbne 2f\n" /* non-zero, return already set */
- "\tstwcx. %2,0,%1\n" /* else store conditional */
- "\tbne- 1b\n" /* retry if lost reservation */
- "\tsync\n" /* import barrier */
- "2:\t\n" /* oldval is zero if we set */
- : "=&r"(oldval), "=p"(addr)
- : "r"(temp), "1"(addr)
- : "cr0","memory");
- return oldval;
- }
-# define GC_TEST_AND_SET_DEFINED
- inline static void GC_clear(volatile unsigned int *addr) {
- __asm__ __volatile__("lwsync" : : : "memory");
- *(addr) = 0;
- }
-# define GC_CLEAR_DEFINED
-# endif
-# if defined(ALPHA)
- inline static int GC_test_and_set(volatile unsigned int * addr)
- {
- unsigned long oldvalue;
- unsigned long temp;
-
- __asm__ __volatile__(
- "1: ldl_l %0,%1\n"
- " and %0,%3,%2\n"
- " bne %2,2f\n"
- " xor %0,%3,%0\n"
- " stl_c %0,%1\n"
-# ifdef __ELF__
- " beq %0,3f\n"
-# else
- " beq %0,1b\n"
-# endif
- " mb\n"
- "2:\n"
-# ifdef __ELF__
- ".section .text2,\"ax\"\n"
- "3: br 1b\n"
- ".previous"
-# endif
- :"=&r" (temp), "=m" (*addr), "=&r" (oldvalue)
- :"Ir" (1), "m" (*addr)
- :"memory");
-
- return oldvalue;
- }
-# define GC_TEST_AND_SET_DEFINED
- inline static void GC_clear(volatile unsigned int *addr) {
- __asm__ __volatile__("mb" : : : "memory");
- *(addr) = 0;
- }
-# define GC_CLEAR_DEFINED
-# endif /* ALPHA */
-# ifdef ARM32
- inline static int GC_test_and_set(volatile unsigned int *addr) {
- int oldval;
- /* SWP on ARM is very similar to XCHG on x86. */
- /* The first operand is the result, the second the value */
- /* to be stored. Both registers must be different from addr. */
- /* Make the address operand an early clobber output so it */
- /* doesn't overlap with the other operands. The early clobber*/
- /* on oldval is neccessary to prevent the compiler allocating */
- /* them to the same register if they are both unused. */
- __asm__ __volatile__("swp %0, %2, [%3]"
- : "=&r"(oldval), "=&r"(addr)
- : "r"(1), "1"(addr)
- : "memory");
- return oldval;
- }
-# define GC_TEST_AND_SET_DEFINED
-# endif /* ARM32 */
-# ifdef CRIS
- inline static int GC_test_and_set(volatile unsigned int *addr) {
- /* Ripped from linuxthreads/sysdeps/cris/pt-machine.h. */
- /* Included with Hans-Peter Nilsson's permission. */
- register unsigned long int ret;
-
- /* Note the use of a dummy output of *addr to expose the write.
- * The memory barrier is to stop *other* writes being moved past
- * this code.
- */
- __asm__ __volatile__("clearf\n"
- "0:\n\t"
- "movu.b [%2],%0\n\t"
- "ax\n\t"
- "move.b %3,[%2]\n\t"
- "bwf 0b\n\t"
- "clearf"
- : "=&r" (ret), "=m" (*addr)
- : "r" (addr), "r" ((int) 1), "m" (*addr)
- : "memory");
- return ret;
- }
-# define GC_TEST_AND_SET_DEFINED
-# endif /* CRIS */
-# ifdef S390
- inline static int GC_test_and_set(volatile unsigned int *addr) {
- int ret;
- __asm__ __volatile__ (
- " l %0,0(%2)\n"
- "0: cs %0,%1,0(%2)\n"
- " jl 0b"
- : "=&d" (ret)
- : "d" (1), "a" (addr)
- : "cc", "memory");
- return ret;
- }
-# endif
-# endif /* __GNUC__ */
-# if (defined(ALPHA) && !defined(__GNUC__))
-# ifndef OSF1
- --> We currently assume that if gcc is not used, we are
- --> running under Tru64.
-# endif
-# include <machine/builtins.h>
-# include <c_asm.h>
-# define GC_test_and_set(addr) __ATOMIC_EXCH_LONG(addr, 1)
-# define GC_TEST_AND_SET_DEFINED
-# define GC_clear(addr) { asm("mb"); *(volatile unsigned *)addr = 0; }
-# define GC_CLEAR_DEFINED
-# endif
-# if defined(MSWIN32)
-# define GC_test_and_set(addr) InterlockedExchange((LPLONG)addr,1)
-# define GC_TEST_AND_SET_DEFINED
-# endif
-# ifdef MIPS
-# ifdef LINUX
-# include <sys/tas.h>
-# define GC_test_and_set(addr) _test_and_set((int *) addr,1)
-# define GC_TEST_AND_SET_DEFINED
-# elif __mips < 3 || !(defined (_ABIN32) || defined(_ABI64)) \
- || !defined(_COMPILER_VERSION) || _COMPILER_VERSION < 700
-# ifdef __GNUC__
-# define GC_test_and_set(addr) _test_and_set((void *)addr,1)
-# else
-# define GC_test_and_set(addr) test_and_set((void *)addr,1)
-# endif
-# else
-# include <sgidefs.h>
-# include <mutex.h>
-# define GC_test_and_set(addr) __test_and_set32((void *)addr,1)
-# define GC_clear(addr) __lock_release(addr);
-# define GC_CLEAR_DEFINED
-# endif
-# define GC_TEST_AND_SET_DEFINED
-# endif /* MIPS */
-# if defined(_AIX)
-# include <sys/atomic_op.h>
-# if (defined(_POWER) || defined(_POWERPC))
-# if defined(__GNUC__)
- inline static void GC_memsync() {
- __asm__ __volatile__ ("sync" : : : "memory");
- }
-# else
-# ifndef inline
-# define inline __inline
-# endif
-# pragma mc_func GC_memsync { \
- "7c0004ac" /* sync (same opcode used for dcs)*/ \
- }
-# endif
-# else
-# error dont know how to memsync
-# endif
- inline static int GC_test_and_set(volatile unsigned int * addr) {
- int oldvalue = 0;
- if (compare_and_swap((void *)addr, &oldvalue, 1)) {
- GC_memsync();
- return 0;
- } else return 1;
- }
-# define GC_TEST_AND_SET_DEFINED
- inline static void GC_clear(volatile unsigned int *addr) {
- GC_memsync();
- *(addr) = 0;
- }
-# define GC_CLEAR_DEFINED
-
+# define UNCOND_LOCK() PCR_Th_ML_Acquire(&GC_allocate_ml)
+# define UNCOND_UNLOCK() PCR_Th_ML_Release(&GC_allocate_ml)
# endif
-# if 0 /* defined(HP_PA) */
- /* The official recommendation seems to be to not use ldcw from */
- /* user mode. Since multithreaded incremental collection doesn't */
- /* work anyway on HP_PA, this shouldn't be a major loss. */
- /* "set" means 0 and "clear" means 1 here. */
-# define GC_test_and_set(addr) !GC_test_and_clear(addr);
-# define GC_TEST_AND_SET_DEFINED
-# define GC_clear(addr) GC_noop1((word)(addr)); *(volatile unsigned int *)addr = 1;
- /* The above needs a memory barrier! */
-# define GC_CLEAR_DEFINED
+# if !defined(AO_HAVE_test_and_set_acquire) && defined(GC_PTHREADS)
+# define USE_PTHREAD_LOCKS
# endif
-# if defined(GC_TEST_AND_SET_DEFINED) && !defined(GC_CLEAR_DEFINED)
-# ifdef __GNUC__
- inline static void GC_clear(volatile unsigned int *addr) {
- /* Try to discourage gcc from moving anything past this. */
- __asm__ __volatile__(" " : : : "memory");
- *(addr) = 0;
- }
-# else
- /* The function call in the following should prevent the */
- /* compiler from moving assignments to below the UNLOCK. */
-# define GC_clear(addr) GC_noop1((word)(addr)); \
- *((volatile unsigned int *)(addr)) = 0;
-# endif
-# define GC_CLEAR_DEFINED
-# endif /* !GC_CLEAR_DEFINED */
-# if !defined(GC_TEST_AND_SET_DEFINED)
+# if defined(GC_WIN32_THREADS) && defined(GC_PTHREADS)
# define USE_PTHREAD_LOCKS
# endif
-# if defined(GC_PTHREADS) && !defined(GC_SOLARIS_THREADS) \
- && !defined(GC_WIN32_THREADS)
-# define NO_THREAD (pthread_t)(-1)
+# 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>
-# if defined(PARALLEL_MARK)
- /* We need compare-and-swap to update mark bits, where it's */
- /* performance critical. If USE_MARK_BYTES is defined, it is */
- /* no longer needed for this purpose. However we use it in */
- /* either case to implement atomic fetch-and-add, though that's */
- /* less performance critical, and could perhaps be done with */
- /* a lock. */
-# if defined(GENERIC_COMPARE_AND_SWAP)
- /* Probably not useful, except for debugging. */
- /* We do use GENERIC_COMPARE_AND_SWAP on PA_RISC, but we */
- /* minimize its use. */
- extern pthread_mutex_t GC_compare_and_swap_lock;
-
- /* Note that if GC_word updates are not atomic, a concurrent */
- /* reader should acquire GC_compare_and_swap_lock. On */
- /* currently supported platforms, such updates are atomic. */
- extern GC_bool GC_compare_and_exchange(volatile GC_word *addr,
- GC_word old, GC_word new_val);
-# endif /* GENERIC_COMPARE_AND_SWAP */
-# if defined(I386)
-# if !defined(GENERIC_COMPARE_AND_SWAP)
- /* Returns TRUE if the comparison succeeded. */
- inline static GC_bool GC_compare_and_exchange(volatile GC_word *addr,
- GC_word old,
- GC_word new_val)
- {
- char result;
- __asm__ __volatile__("lock; cmpxchgl %2, %0; setz %1"
- : "+m"(*(addr)), "=r"(result)
- : "r" (new_val), "a"(old) : "memory");
- return (GC_bool) result;
- }
-# endif /* !GENERIC_COMPARE_AND_SWAP */
- inline static void GC_memory_barrier()
- {
- /* We believe the processor ensures at least processor */
- /* consistent ordering. Thus a compiler barrier */
- /* should suffice. */
- __asm__ __volatile__("" : : : "memory");
- }
-# endif /* I386 */
-
-# if defined(POWERPC)
-# if !defined(GENERIC_COMPARE_AND_SWAP)
-# if CPP_WORDSZ == 64
- /* Returns TRUE if the comparison succeeded. */
- inline static GC_bool GC_compare_and_exchange(volatile GC_word *addr,
- GC_word old, GC_word new_val)
- {
- unsigned long result, dummy;
- __asm__ __volatile__(
- "1:\tldarx %0,0,%5\n"
- "\tcmpd %0,%4\n"
- "\tbne 2f\n"
- "\tstdcx. %3,0,%2\n"
- "\tbne- 1b\n"
- "\tsync\n"
- "\tli %1, 1\n"
- "\tb 3f\n"
- "2:\tli %1, 0\n"
- "3:\t\n"
- : "=&r" (dummy), "=r" (result), "=p" (addr)
- : "r" (new_val), "r" (old), "2"(addr)
- : "cr0","memory");
- return (GC_bool) result;
- }
-# else
- /* Returns TRUE if the comparison succeeded. */
- inline static GC_bool GC_compare_and_exchange(volatile GC_word *addr,
- GC_word old, GC_word new_val)
- {
- int result, dummy;
- __asm__ __volatile__(
- "1:\tlwarx %0,0,%5\n"
- "\tcmpw %0,%4\n"
- "\tbne 2f\n"
- "\tstwcx. %3,0,%2\n"
- "\tbne- 1b\n"
- "\tsync\n"
- "\tli %1, 1\n"
- "\tb 3f\n"
- "2:\tli %1, 0\n"
- "3:\t\n"
- : "=&r" (dummy), "=r" (result), "=p" (addr)
- : "r" (new_val), "r" (old), "2"(addr)
- : "cr0","memory");
- return (GC_bool) result;
- }
-# endif
-# endif /* !GENERIC_COMPARE_AND_SWAP */
- inline static void GC_memory_barrier()
- {
- __asm__ __volatile__("sync" : : : "memory");
- }
-# endif /* POWERPC */
-
-# if defined(IA64)
-# if !defined(GENERIC_COMPARE_AND_SWAP)
- inline static GC_bool GC_compare_and_exchange(volatile GC_word *addr,
- GC_word old, GC_word new_val)
- {
- unsigned long oldval;
-# if CPP_WORDSZ == 32
- __asm__ __volatile__(
- "addp4 %0=0,%1\n"
- "mov ar.ccv=%3 ;; cmpxchg4.rel %0=[%0],%2,ar.ccv"
- : "=&r"(oldval)
- : "r"(addr), "r"(new_val), "r"(old) : "memory");
-# else
- __asm__ __volatile__(
- "mov ar.ccv=%3 ;; cmpxchg8.rel %0=[%1],%2,ar.ccv"
- : "=r"(oldval)
- : "r"(addr), "r"(new_val), "r"(old) : "memory");
-# endif
- return (oldval == old);
- }
-# endif /* !GENERIC_COMPARE_AND_SWAP */
-# if 0
- /* Shouldn't be needed; we use volatile stores instead. */
- inline static void GC_memory_barrier()
- {
- __asm__ __volatile__("mf" : : : "memory");
- }
-# endif /* 0 */
-# endif /* IA64 */
-# if defined(ALPHA)
-# if !defined(GENERIC_COMPARE_AND_SWAP)
-# if defined(__GNUC__)
- inline static GC_bool GC_compare_and_exchange(volatile GC_word *addr,
- GC_word old, GC_word new_val)
- {
- unsigned long was_equal;
- unsigned long temp;
-
- __asm__ __volatile__(
- "1: ldq_l %0,%1\n"
- " cmpeq %0,%4,%2\n"
- " mov %3,%0\n"
- " beq %2,2f\n"
- " stq_c %0,%1\n"
- " beq %0,1b\n"
- "2:\n"
- " mb\n"
- :"=&r" (temp), "=m" (*addr), "=&r" (was_equal)
- : "r" (new_val), "Ir" (old)
- :"memory");
- return was_equal;
- }
-# else /* !__GNUC__ */
- inline static GC_bool GC_compare_and_exchange(volatile GC_word *addr,
- GC_word old, GC_word new_val)
- {
- return __CMP_STORE_QUAD(addr, old, new_val, addr);
- }
-# endif /* !__GNUC__ */
-# endif /* !GENERIC_COMPARE_AND_SWAP */
-# ifdef __GNUC__
- inline static void GC_memory_barrier()
- {
- __asm__ __volatile__("mb" : : : "memory");
- }
+
+ /* 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
-# define GC_memory_barrier() asm("mb")
-# endif /* !__GNUC__ */
-# endif /* ALPHA */
-# if defined(S390)
-# if !defined(GENERIC_COMPARE_AND_SWAP)
- inline static GC_bool GC_compare_and_exchange(volatile C_word *addr,
- GC_word old, GC_word new_val)
- {
- int retval;
- __asm__ __volatile__ (
-# ifndef __s390x__
- " cs %1,%2,0(%3)\n"
-# else
- " csg %1,%2,0(%3)\n"
-# endif
- " ipm %0\n"
- " srl %0,28\n"
- : "=&d" (retval), "+d" (old)
- : "d" (new_val), "a" (addr)
- : "cc", "memory");
- return retval == 0;
- }
+ /* 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
-# if !defined(GENERIC_COMPARE_AND_SWAP)
- /* Returns the original value of *addr. */
- inline static GC_word GC_atomic_add(volatile GC_word *addr,
- GC_word how_much)
- {
- GC_word old;
- do {
- old = *addr;
- } while (!GC_compare_and_exchange(addr, old, old+how_much));
- return old;
- }
-# else /* GENERIC_COMPARE_AND_SWAP */
- /* So long as a GC_word can be atomically updated, it should */
- /* be OK to read *addr without a lock. */
- extern GC_word GC_atomic_add(volatile GC_word *addr, GC_word how_much);
-# endif /* GENERIC_COMPARE_AND_SWAP */
-
-# endif /* PARALLEL_MARK */
+# 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 */
/* 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 unsigned int GC_allocate_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 LOCK() \
- { if (GC_test_and_set(&GC_allocate_lock)) GC_lock(); \
+# define UNCOND_LOCK() \
+ { if (AO_test_and_set_acquire(&GC_allocate_lock) == AO_TS_SET) \
+ GC_lock(); \
SET_LOCK_HOLDER(); }
-# define UNLOCK() \
+# define UNCOND_UNLOCK() \
{ GC_ASSERT(I_HOLD_LOCK()); UNSET_LOCK_HOLDER(); \
- GC_clear(&GC_allocate_lock); }
+ AO_CLEAR(&GC_allocate_lock); }
# else
-# define LOCK() \
- { if (GC_test_and_set(&GC_allocate_lock)) GC_lock(); }
-# define UNLOCK() \
- GC_clear(&GC_allocate_lock)
+# 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 */
-# if 0
- /* Another alternative for OSF1 might be: */
-# include <sys/mman.h>
- extern msemaphore GC_allocate_semaphore;
-# define LOCK() { if (msem_lock(&GC_allocate_semaphore, MSEM_IF_NOWAIT) \
- != 0) GC_lock(); else GC_allocate_lock = 1; }
- /* The following is INCORRECT, since the memory model is too weak. */
- /* Is this true? Presumably msem_unlock has the right semantics? */
- /* - HB */
-# define UNLOCK() { GC_allocate_lock = 0; \
- msem_unlock(&GC_allocate_semaphore, 0); }
-# endif /* 0 */
# else /* THREAD_LOCAL_ALLOC || USE_PTHREAD_LOCKS */
# ifndef USE_PTHREAD_LOCKS
# define USE_PTHREAD_LOCKS
# endif
-# endif /* THREAD_LOCAL_ALLOC */
-# ifdef USE_PTHREAD_LOCKS
+# 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 LOCK() \
+# define UNCOND_LOCK() \
{ GC_lock(); \
SET_LOCK_HOLDER(); }
-# define UNLOCK() \
+# 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 LOCK() GC_lock();
+# define UNCOND_LOCK() GC_lock();
# else /* !defined(NO_PTHREAD_TRYLOCK) */
-# define LOCK() \
+# define UNCOND_LOCK() \
{ if (0 != pthread_mutex_trylock(&GC_allocate_ml)) GC_lock(); }
# endif
-# define UNLOCK() pthread_mutex_unlock(&GC_allocate_ml)
+# define UNCOND_UNLOCK() pthread_mutex_unlock(&GC_allocate_ml)
# endif /* !GC_ASSERTIONS */
-# endif /* USE_PTHREAD_LOCKS */
-# define SET_LOCK_HOLDER() GC_lock_holder = pthread_self()
-# define UNSET_LOCK_HOLDER() GC_lock_holder = NO_THREAD
-# define I_HOLD_LOCK() (pthread_equal(GC_lock_holder, pthread_self()))
- extern VOLATILE GC_bool GC_collecting;
-# define ENTER_GC() GC_collecting = 1;
-# define EXIT_GC() GC_collecting = 0;
- extern void GC_lock(void);
- extern pthread_t GC_lock_holder;
-# ifdef GC_ASSERTIONS
- extern pthread_t GC_mark_lock_holder;
-# endif
-# endif /* GC_PTHREADS with linux_threads.c implementation */
-# if defined(GC_WIN32_THREADS)
-# if defined(GC_PTHREADS)
-# include <pthread.h>
- extern pthread_mutex_t GC_allocate_ml;
-# define LOCK() pthread_mutex_lock(&GC_allocate_ml)
-# define UNLOCK() pthread_mutex_unlock(&GC_allocate_ml)
+# 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
-# include <windows.h>
- GC_API CRITICAL_SECTION GC_allocate_ml;
-# define LOCK() EnterCriticalSection(&GC_allocate_ml);
-# define UNLOCK() LeaveCriticalSection(&GC_allocate_ml);
+# define I_DONT_HOLD_LOCK() \
+ (!GC_need_to_lock \
+ || GC_lock_holder != NUMERIC_THREAD_ID(pthread_self()))
# endif
-# endif
-# ifndef SET_LOCK_HOLDER
-# define SET_LOCK_HOLDER()
-# define UNSET_LOCK_HOLDER()
-# define I_HOLD_LOCK() FALSE
- /* Used on platforms were locks can be reacquired, */
- /* so it doesn't matter if we lie. */
-# 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()
-# endif /* !THREADS */
-# ifndef SET_LOCK_HOLDER
+# define LOCK()
+# define UNLOCK()
# define SET_LOCK_HOLDER()
# define UNSET_LOCK_HOLDER()
-# define I_HOLD_LOCK() FALSE
- /* Used on platforms were locks can be reacquired, */
- /* so it doesn't matter if we lie. */
-# endif
+# define I_HOLD_LOCK() TRUE
+# define I_DONT_HOLD_LOCK() TRUE
+ /* Used only in positive assertions or to test whether */
+ /* we still need to acquire 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()
# ifndef DCL_LOCK_STATE
# define DCL_LOCK_STATE
# endif
-# ifndef FASTLOCK
-# define FASTLOCK() LOCK()
-# define FASTLOCK_SUCCEEDED() TRUE
-# define FASTUNLOCK() UNLOCK()
-# endif
#endif /* GC_LOCKS_H */
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