gc6.0 tarball importgc6_0

1 files changed, 481 insertions, 0 deletions

diff --git a/include/private/gc_locks.h b/include/private/gc_locks.h
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+++ b/include/private/gc_locks.h
@@ -0,0 +1,481 @@
+/* 
+ * 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.
+ * 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.)
+ *
+ * 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( )
+ *   
+ */  
+# 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
+#  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 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)
+       inline static int GC_test_and_set(volatile unsigned int *addr) {
+	  long oldval, n = 1;
+	  __asm__ __volatile__("xchg4 %0=%1,%2"
+		: "=r"(oldval), "=m"(*addr)
+		: "r"(n), "1"(*addr) : "memory");
+	  return oldval;
+       }
+#      define GC_TEST_AND_SET_DEFINED
+       /* Should this handle post-increment addressing?? */
+       inline static void GC_clear(volatile unsigned int *addr) {
+	 __asm__ __volatile__("st4.rel %0=r0" : "=m" (*addr) : : "memory");
+       }
+#      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
+               "2:\t\n"                // oldval is zero if we set
+              : "=&r"(oldval), "=p"(addr)
+              : "r"(temp), "1"(addr)
+              : "memory");
+          return (int)oldval;
+        }
+#       define GC_TEST_AND_SET_DEFINED
+        inline static void GC_clear(volatile unsigned int *addr) {
+	  __asm__ __volatile__("eieio" ::: "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"
+                             "       beq %0,3f\n"
+                             "       mb\n"
+                             "2:\n"
+                             ".section .text2,\"ax\"\n"
+                             "3:     br 1b\n"
+                             ".previous"
+                             :"=&r" (temp), "=m" (*addr), "=&r" (oldvalue)
+                             :"Ir" (1), "m" (*addr)
+			     :"memory");
+
+          return oldvalue;
+        }
+#       define GC_TEST_AND_SET_DEFINED
+        /* Should probably also define GC_clear, since it needs	*/
+        /* a memory barrier ??					*/
+#    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.  Doesn't lock the
+           * bus because there are no SMP ARM machines.  If/when there are,
+           * this code will likely need to be updated. */
+          /* See linuxthreads/sysdeps/arm/pt-machine.h in glibc-2.1 */
+          __asm__ __volatile__("swp %0, %1, [%2]"
+      		  	     : "=r"(oldval)
+      			     : "r"(1), "r"(addr)
+			     : "memory");
+          return oldval;
+        }
+#       define GC_TEST_AND_SET_DEFINED
+#    endif /* ARM32 */
+#  endif /* __GNUC__ */
+#  if (defined(ALPHA) && !defined(__GNUC__))
+#    define GC_test_and_set(addr) __cxx_test_and_set_atomic(addr, 1)
+#    define GC_TEST_AND_SET_DEFINED
+#  endif
+#  if defined(MSWIN32)
+#    define GC_test_and_set(addr) InterlockedExchange((LPLONG)addr,1)
+#    define GC_TEST_AND_SET_DEFINED
+#  endif
+#  ifdef MIPS
+#    if __mips < 3 || !(defined (_ABIN32) || defined(_ABI64)) \
+	|| !defined(_COMPILER_VERSION) || _COMPILER_VERSION < 700
+#        define GC_test_and_set(addr, v) test_and_set(addr,v)
+#    else
+#	 define GC_test_and_set(addr, v) __test_and_set(addr,v)
+#	 define GC_clear(addr) __lock_release(addr);
+#	 define GC_CLEAR_DEFINED
+#    endif
+#    define GC_TEST_AND_SET_DEFINED
+#  endif /* MIPS */
+#  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
+#  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)
+#    define USE_PTHREAD_LOCKS
+#  endif
+
+#  if defined(LINUX_THREADS) || defined(OSF1_THREADS) \
+      || defined(HPUX_THREADS)
+#    define NO_THREAD (pthread_t)(-1)
+#    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), "0"(*(addr)), "a"(old) : "memory");
+	   return (GC_bool) result;
+         }
+#      endif /* !GENERIC_COMPARE_AND_SWAP */
+       inline static void GC_memory_write_barrier()
+       {
+	 /* We believe the processor ensures at least processor	*/
+	 /* consistent ordering.  Thus a compiler barrier	*/
+	 /* should suffice.					*/
+         __asm__ __volatile__("" : : : "memory");
+       }
+#     endif /* I386 */
+#     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;
+	  __asm__ __volatile__("mov ar.ccv=%4 ;; cmpxchg8.rel %0=%1,%2,ar.ccv"
+		: "=r"(oldval), "=m"(*addr)
+		: "r"(new_val), "1"(*addr), "r"(old) : "memory");
+	  return (oldval == old);
+         }
+#      endif /* !GENERIC_COMPARE_AND_SWAP */
+#      if 0
+	/* Shouldn't be needed; we use volatile stores instead. */
+        inline static void GC_memory_write_barrier()
+        {
+          __asm__ __volatile__("mf" : : : "memory");
+        }
+#      endif /* 0 */
+#     endif /* IA64 */
+#     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 */
+
+#    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 unsigned int 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(); \
+		  SET_LOCK_HOLDER(); }
+#        define UNLOCK() \
+		{ GC_ASSERT(I_HOLD_LOCK()); UNSET_LOCK_HOLDER(); \
+	          GC_clear(&GC_allocate_lock); }
+#     else
+#        define LOCK() \
+		{ if (GC_test_and_set(&GC_allocate_lock)) GC_lock(); }
+#        define UNLOCK() \
+		GC_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
+#      include <pthread.h>
+       extern pthread_mutex_t GC_allocate_ml;
+#      ifdef GC_ASSERTIONS
+#        define LOCK() \
+		{ GC_lock(); \
+		  SET_LOCK_HOLDER(); }
+#        define UNLOCK() \
+		{ GC_ASSERT(I_HOLD_LOCK()); UNSET_LOCK_HOLDER(); \
+	          pthread_mutex_unlock(&GC_allocate_ml); }
+#      else /* !GC_ASSERTIONS */
+#        define LOCK() \
+	   { if (0 != pthread_mutex_trylock(&GC_allocate_ml)) GC_lock(); }
+#        define 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 /* LINUX_THREADS || OSF1_THREADS  || HPUX_THREADS */
+#  if defined(IRIX_THREADS)
+#    include <pthread.h>
+     /* This probably should never be included, but I can't test	*/
+     /* on Irix anymore.						*/
+#    include <mutex.h>
+
+     extern unsigned long GC_allocate_lock;
+	/* This is not a mutex because mutexes that obey the (optional) 	*/
+	/* POSIX scheduling rules are subject to convoys in high contention	*/
+	/* applications.  This is basically a spin lock.			*/
+     extern pthread_t GC_lock_holder;
+     extern void GC_lock(void);
+	/* Allocation lock holder.  Only set if acquired by client through */
+	/* GC_call_with_alloc_lock.					   */
+#    define SET_LOCK_HOLDER() GC_lock_holder = pthread_self()
+#    define NO_THREAD (pthread_t)(-1)
+#    define UNSET_LOCK_HOLDER() GC_lock_holder = NO_THREAD
+#    define I_HOLD_LOCK() (pthread_equal(GC_lock_holder, pthread_self()))
+#    define LOCK() { if (GC_test_and_set(&GC_allocate_lock, 1)) GC_lock(); }
+#    define UNLOCK() GC_clear(&GC_allocate_lock);
+     extern VOLATILE GC_bool GC_collecting;
+#    define ENTER_GC() \
+		{ \
+		    GC_collecting = 1; \
+		}
+#    define EXIT_GC() GC_collecting = 0;
+#  endif /* IRIX_THREADS */
+#  ifdef WIN32_THREADS
+#    include <windows.h>
+     GC_API CRITICAL_SECTION GC_allocate_ml;
+#    define LOCK() EnterCriticalSection(&GC_allocate_ml);
+#    define UNLOCK() LeaveCriticalSection(&GC_allocate_ml);
+#  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
+# else /* !THREADS */
+#    define LOCK()
+#    define UNLOCK()
+# endif /* !THREADS */
+# 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
+# ifndef ENTER_GC
+#   define ENTER_GC()
+#   define EXIT_GC()
+# endif
+
+# 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 */