/* -----------------------------------------------------------------------------
- * $Id: Stable.c,v 1.25 2003/03/31 19:19:34 sof Exp $
*
* (c) The GHC Team, 1998-2002
*
#include "PosixSource.h"
#include "Rts.h"
#include "Hash.h"
-#include "StablePriv.h"
#include "RtsUtils.h"
+#include "OSThreads.h"
#include "Storage.h"
#include "RtsAPI.h"
#include "RtsFlags.h"
+#include "OSThreads.h"
/* Comment from ADR's implementation in old RTS:
There may be additional functions on the C side to allow evaluation,
application, etc of a stable pointer.
- When Haskell calls C, it normally just passes over primitive integers,
- floats, bools, strings, etc. This doesn't cause any problems at all
- for garbage collection because the act of passing them makes a copy
- from the heap, stack or wherever they are onto the C-world stack.
- However, if we were to pass a heap object such as a (Haskell) @String@
- and a garbage collection occured before we finished using it, we'd run
- into problems since the heap object might have been moved or even
- deleted.
-
- So, if a C call is able to cause a garbage collection or we want to
- store a pointer to a heap object between C calls, we must be careful
- when passing heap objects. Our solution is to keep a table of all
- objects we've given to the C-world and to make sure that the garbage
- collector collects these objects --- updating the table as required to
- make sure we can still find the object.
*/
snEntry *stable_ptr_table = NULL;
static unsigned int SPT_size = 0;
+#ifdef THREADED_RTS
+static Mutex stable_mutex;
+#endif
+
/* This hash table maps Haskell objects to stable names, so that every
* call to lookupStableName on a given object will return the same
* stable name.
#define INIT_SPT_SIZE 64
-static inline void
+STATIC_INLINE void
initFreeList(snEntry *table, nat n, snEntry *free)
{
snEntry *p;
void
initStablePtrTable(void)
{
- // Nothing to do:
- // the table will be allocated the first time makeStablePtr is
- // called, and we want the table to persist through multiple inits.
+ if (SPT_size > 0)
+ return;
+
+ SPT_size = INIT_SPT_SIZE;
+ stable_ptr_table = stgMallocBytes(SPT_size * sizeof(snEntry),
+ "initStablePtrTable");
+
+ /* we don't use index 0 in the stable name table, because that
+ * would conflict with the hash table lookup operations which
+ * return NULL if an entry isn't found in the hash table.
+ */
+ initFreeList(stable_ptr_table+1,INIT_SPT_SIZE-1,NULL);
+ addrToStableHash = allocHashTable();
+
+#ifdef THREADED_RTS
+ initMutex(&stable_mutex);
+#endif
}
/*
return q;
}
-StgWord
-lookupStableName(StgPtr p)
+static StgWord
+lookupStableName_(StgPtr p)
{
StgWord sn;
+ void* sn_tmp;
if (stable_ptr_free == NULL) {
enlargeStablePtrTable();
*/
p = (StgPtr)removeIndirections((StgClosure*)p);
- (void *)sn = lookupHashTable(addrToStableHash,(W_)p);
+ sn_tmp = lookupHashTable(addrToStableHash,(W_)p);
+ sn = (StgWord)sn_tmp;
if (sn != 0) {
ASSERT(stable_ptr_table[sn].addr == p);
- IF_DEBUG(stable,fprintf(stderr,"cached stable name %d at %p\n",sn,p));
+ IF_DEBUG(stable,debugBelch("cached stable name %ld at %p\n",sn,p));
return sn;
} else {
sn = stable_ptr_free - stable_ptr_table;
- (P_)stable_ptr_free = stable_ptr_free->addr;
+ stable_ptr_free = (snEntry*)(stable_ptr_free->addr);
stable_ptr_table[sn].ref = 0;
stable_ptr_table[sn].addr = p;
stable_ptr_table[sn].sn_obj = NULL;
- /* IF_DEBUG(stable,fprintf(stderr,"new stable name %d at
- %p\n",sn,p)); */
+ /* IF_DEBUG(stable,debugBelch("new stable name %d at %p\n",sn,p)); */
/* add the new stable name to the hash table */
insertHashTable(addrToStableHash, (W_)p, (void *)sn);
}
}
-static inline void
+StgWord
+lookupStableName(StgPtr p)
+{
+ StgWord res;
+
+ initStablePtrTable();
+ ACQUIRE_LOCK(&stable_mutex);
+ res = lookupStableName_(p);
+ RELEASE_LOCK(&stable_mutex);
+ return res;
+}
+
+STATIC_INLINE void
freeStableName(snEntry *sn)
{
ASSERT(sn->sn_obj == NULL);
{
StgWord sn;
- sn = lookupStableName(p);
+ initStablePtrTable();
+ ACQUIRE_LOCK(&stable_mutex);
+ sn = lookupStableName_(p);
stable_ptr_table[sn].ref++;
+ RELEASE_LOCK(&stable_mutex);
return (StgStablePtr)(sn);
}
void
freeStablePtr(StgStablePtr sp)
{
- snEntry *sn = &stable_ptr_table[(StgWord)sp];
+ snEntry *sn;
+
+ initStablePtrTable();
+ ACQUIRE_LOCK(&stable_mutex);
+
+ sn = &stable_ptr_table[(StgWord)sp];
ASSERT((StgWord)sp < SPT_size && sn->addr != NULL && sn->ref > 0);
if (sn->sn_obj == NULL && sn->ref == 0) {
freeStableName(sn);
}
+
+ RELEASE_LOCK(&stable_mutex);
}
void
enlargeStablePtrTable(void)
{
nat old_SPT_size = SPT_size;
-
- if (SPT_size == 0) {
- // 1st time
- SPT_size = INIT_SPT_SIZE;
- stable_ptr_table = stgMallocBytes(SPT_size * sizeof(snEntry),
- "enlargeStablePtrTable");
-
- /* we don't use index 0 in the stable name table, because that
- * would conflict with the hash table lookup operations which
- * return NULL if an entry isn't found in the hash table.
- */
- initFreeList(stable_ptr_table+1,INIT_SPT_SIZE-1,NULL);
- addrToStableHash = allocHashTable();
- }
- else {
+
// 2nd and subsequent times
- SPT_size *= 2;
- stable_ptr_table =
- stgReallocBytes(stable_ptr_table,
+ SPT_size *= 2;
+ stable_ptr_table =
+ stgReallocBytes(stable_ptr_table,
SPT_size * sizeof(snEntry),
"enlargeStablePtrTable");
- initFreeList(stable_ptr_table + old_SPT_size, old_SPT_size, NULL);
- }
+ initFreeList(stable_ptr_table + old_SPT_size, old_SPT_size, NULL);
}
/* -----------------------------------------------------------------------------
if (p->sn_obj == NULL) {
// StableName object is dead
freeStableName(p);
- IF_DEBUG(stable, fprintf(stderr,"GC'd Stable name %d\n",
- p - stable_ptr_table));
+ IF_DEBUG(stable, debugBelch("GC'd Stable name %ld\n",
+ p - stable_ptr_table));
continue;
} else {
- (StgClosure *)p->addr = isAlive((StgClosure *)p->addr);
- IF_DEBUG(stable, fprintf(stderr,"Stable name %d still alive at %p, ref %d\n", p - stable_ptr_table, p->addr, p->ref));
+ p->addr = (StgPtr)isAlive((StgClosure *)p->addr);
+ IF_DEBUG(stable, debugBelch("Stable name %ld still alive at %p, ref %ld\n", p - stable_ptr_table, p->addr, p->ref));
}
}
}
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