X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Frts%2FStable.c;h=09efb6accc6cc3417312050f615fcd7e9d08198c;hb=12694df2b002fe264d1e9e8209e0fbb6914ffe50;hp=474134efebf1eed64e777629883a223070dc2c58;hpb=ce25c38a23ae200cd8acd04d28b228967db60a5b;p=ghc-hetmet.git

diff --git a/ghc/rts/Stable.c b/ghc/rts/Stable.c
index 474134e..09efb6a 100644
--- a/ghc/rts/Stable.c
+++ b/ghc/rts/Stable.c
@@ -1,20 +1,23 @@
 /* -----------------------------------------------------------------------------
- * $Id: Stable.c,v 1.21 2002/04/24 13:29:01 simonmar Exp $
  *
- * (c) The GHC Team, 1998-1999
+ * (c) The GHC Team, 1998-2002
  *
  * Stable names and stable pointers.
  *
  * ---------------------------------------------------------------------------*/
 
+// Make static versions of inline functions in Stable.h:
+#define RTS_STABLE_C
+
 #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:
 
@@ -70,27 +73,16 @@
   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;
-snEntry *stable_ptr_free;
+snEntry *stable_ptr_table = NULL;
+static snEntry *stable_ptr_free = NULL;
+
+static unsigned int SPT_size = 0;
 
-unsigned int SPT_size;
+#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
@@ -125,11 +117,11 @@ unsigned int SPT_size;
  * to the weight stored in the table entry.
  * */
 
-HashTable *addrToStableHash;
+static HashTable *addrToStableHash = NULL;
 
 #define INIT_SPT_SIZE 64
 
-static inline void
+STATIC_INLINE void
 initFreeList(snEntry *table, nat n, snEntry *free)
 {
   snEntry *p;
@@ -147,12 +139,15 @@ initFreeList(snEntry *table, nat n, snEntry *free)
 void
 initStablePtrTable(void)
 {
-  /* the table will be allocated the first time makeStablePtr is
-   * called */
-  stable_ptr_table = NULL;
-  stable_ptr_free  = NULL;
-  addrToStableHash = NULL;
-  SPT_size = 0;
+    // Nothing to do:
+    // the table will be allocated the first time makeStablePtr is
+    // called, and we want the table to persist through multiple inits.
+    //
+    // Also, getStablePtr is now called from __attribute__((constructor))
+    // functions, so initialising things here wouldn't work anyway.
+#ifdef THREADED_RTS
+    initMutex(&stable_mutex);
+#endif
 }
 
 /*
@@ -176,10 +171,11 @@ removeIndirections(StgClosure* p)
   return q;
 }
 
-StgWord
-lookupStableName(StgPtr p)
+static StgWord
+lookupStableName_(StgPtr p)
 {
   StgWord sn;
+  void* sn_tmp;
 
   if (stable_ptr_free == NULL) {
     enlargeStablePtrTable();
@@ -190,20 +186,20 @@ lookupStableName(StgPtr p)
    */
   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);
@@ -212,7 +208,17 @@ lookupStableName(StgPtr p)
   }
 }
 
-static inline void
+StgWord
+lookupStableName(StgPtr p)
+{
+    StgWord res;
+    ACQUIRE_LOCK(&stable_mutex);
+    res = lookupStableName_(p);
+    RELEASE_LOCK(&stable_mutex);
+    return res;
+}
+
+STATIC_INLINE void
 freeStableName(snEntry *sn)
 {
   ASSERT(sn->sn_obj == NULL);
@@ -228,15 +234,21 @@ getStablePtr(StgPtr p)
 {
   StgWord sn;
 
-  sn = lookupStableName(p);
+  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;
+
+    ACQUIRE_LOCK(&stable_mutex);
+
+    sn = &stable_ptr_table[(StgWord)sp];
     
     ASSERT((StgWord)sp < SPT_size  &&  sn->addr != NULL  &&  sn->ref > 0);
 
@@ -248,6 +260,8 @@ freeStablePtr(StgStablePtr sp)
     if (sn->sn_obj == NULL && sn->ref == 0) {
 	freeStableName(sn);
     }
+
+    RELEASE_LOCK(&stable_mutex);
 }
 
 void
@@ -258,8 +272,8 @@ enlargeStablePtrTable(void)
   if (SPT_size == 0) {
     // 1st time
     SPT_size = INIT_SPT_SIZE;
-    stable_ptr_table = stgMallocWords(SPT_size * sizeof(snEntry), 
-				      "initStablePtrTable");
+    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
@@ -272,9 +286,10 @@ enlargeStablePtrTable(void)
     // 2nd and subsequent times
     SPT_size *= 2;
     stable_ptr_table = 
-      stgReallocWords(stable_ptr_table, SPT_size * sizeof(snEntry),
+      stgReallocBytes(stable_ptr_table, 
+		      SPT_size * sizeof(snEntry),
 		      "enlargeStablePtrTable");
-    
+
     initFreeList(stable_ptr_table + old_SPT_size, old_SPT_size, NULL);
   }
 }
@@ -387,13 +402,13 @@ gcStablePtrTable( void )
 		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));
 		}
 	    }
 	}