logical update semantics:

instance of erased element should fail;
  garbage collection now tries to recover space for code.


git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@512 b08c6af1-5177-4d33-ba66-4b1c6b8b522a

C/dbase.c

@@ -3684,10 +3684,18 @@ p_instance(void)
 {
   Term            TermDB;
   Term t1 = Deref(ARG1);
+  DBRef dbr;
 
   if (IsVarTerm(t1) || !IsDBRefTerm(t1))
     return (FALSE);
-  while ((TermDB = GetDBTerm(DBRefOfTerm(t1))) == (CELL)0) {
+  dbr = DBRefOfTerm(t1);
+  if (dbr->Flags & ErasedMask) {
+    /* instance/2 of erased terms should fail under log update
+       semantics */
+    if (dbr->Parent != NULL && dbr->Parent->KindOfPE & LogUpdDBBit)
+      return(FALSE);
+  }
+  while ((TermDB = GetDBTerm(dbr)) == (CELL)0) {
     /* oops, we are in trouble, not enough stack space */
     gc(2, ENV, P);
     t1 = Deref(ARG1);

C/heapgc.c

@@ -583,7 +583,7 @@ init_dbtable(tr_fr_ptr trail_ptr) {
       flags = Flags((CELL)pt0);
       /* for the moment, if all references to the term in the stacks
 	 are only pointers, reset the flag */
-      if (FlagOn(DBClMask, flags) && !FlagOn(LogUpdMask, flags)) {
+      if (FlagOn(DBClMask, flags)) {
 	if (FlagOn(DBNoVars, flags)) {
 	  CODEADDR entry = ((CODEADDR)pt0 - (CELL) &(((DBRef) NIL)->Flags));
 	  store_ref_in_dbtable((DBRef)entry);
@@ -879,7 +879,14 @@ mark_variable(CELL_PTR current)
       if ((Functor)cnext == FunctorDBRef) {
 	DBRef tref = DBRefOfTerm(ccur);
 	/* make sure the reference is marked as in use */
-	tref->Flags |= GcFoundMask;
+	if ((tref->Flags & ErasedMask) &&
+	    tref->Parent != NULL &&
+	    tref->Parent->KindOfPE & LogUpdDBBit) {
+	  *current = MkDBRefTerm(DBErasedMarker);
+	  MARK(current);
+	} else {
+	  tref->Flags |= GcFoundMask;
+	}
       } else {
 	mark_db_fixed(next);
       }
@@ -930,6 +937,7 @@ mark_variable(CELL_PTR current)
 	POP_CONTINUATION();
       }
     }
+    if (next < H0) POP_CONTINUATION();
 #ifdef INSTRUMENT_GC
     inc_vars_of_type(next,gc_func);
 #endif
@@ -982,7 +990,14 @@ mark_external_reference(CELL *ptr) {
 	if ((Functor)(*next) == FunctorDBRef) {
 	  DBRef tref = DBRefOfTerm(reg);
 	  /* make sure the reference is marked as in use */
-	  tref->Flags |= GcFoundMask;
+	  if ((tref->Flags & ErasedMask) &&
+	      tref->Parent != NULL &&
+	      tref->Parent->KindOfPE & LogUpdDBBit) {
+	    *ptr = MkDBRefTerm(DBErasedMarker);
+	    MARK(ptr);
+	  } else {
+	    tref->Flags |= GcFoundMask;
+	  }
 	} else {
 	  mark_db_fixed(next);
 	}
@@ -1852,8 +1867,8 @@ sweep_trail(choiceptr gc_B, tr_fr_ptr old_TR)
 	}
 #endif
       
-	if (!FlagOn(GcFoundMask, flags)) {
+	if (!FlagOn(GcFoundMask, flags) && !FlagOn(LogUpdMask, flags)) {
-	  if (FlagOn(DBClMask, flags)  && !FlagOn(LogUpdMask, flags)) {
+	  if (FlagOn(DBClMask, flags)) {
 	    Flags((CELL)pt0) = ResetFlag(InUseMask, flags);
 	    if (FlagOn(ErasedMask, flags)) {
 	      ErDBE((DBRef) ((CELL)pt0 - (CELL) &(((DBRef) NIL)->Flags)));
@@ -3076,7 +3091,7 @@ static Int
 p_gc(void)
 {
 #ifndef FIXED_STACKS
-  do_gc(0, ENV, CP);
+  do_gc(0, ENV, P);
 #endif  /* FIXED_STACKS */
   return(TRUE);
 }

C/init.c

@@ -1070,8 +1070,16 @@ InitCodes(void)
   heap_regs->getworkcode.u.ld.p = (CODEADDR)RepPredProp(PredPropByAtom(LookupAtom("$getwork"), 0));
   heap_regs->getworkcode_seq.u.ld.p = (CODEADDR)RepPredProp(PredPropByAtom(LookupAtom("$getwork_seq"), 0));
 #endif
+  heap_regs->db_erased_marker =
+    (DBRef)AllocCodeSpace(sizeof(DBStruct));
+  heap_regs->db_erased_marker->id = FunctorDBRef;
+  heap_regs->db_erased_marker->Flags = ErasedMask;
+  heap_regs->db_erased_marker->Code = NULL;
+  INIT_LOCK(heap_regs->db_erased_marker->lock);
+  INIT_DBREF_COUNT(heap_regs->db_erased_marker);
 }
 
+
 static void 
 InitVersion(void)
 {

C/save.c

@@ -1158,6 +1158,8 @@ restore_codes(void)
 #endif
   if (heap_regs->last_wtime != NULL)
     heap_regs->last_wtime = (void *)PtoHeapCellAdjust((CELL *)(heap_regs->last_wtime));
+  heap_regs->db_erased_marker =
+    DBRefAdjust(heap_regs->db_erased_marker);
 }
 
 /* restore some heap registers */

H/Heap.h

@@ -10,7 +10,7 @@
 * File:		Heap.h         						 *
 * mods:									 *
 * comments:	Heap Init Structure					 *
-* version:      $Id: Heap.h,v 1.26 2002-05-23 03:52:34 vsc Exp $	 *
+* version:      $Id: Heap.h,v 1.27 2002-06-04 00:46:32 vsc Exp $	 *
 *************************************************************************/
 
 /* information that can be stored in Code Space */
@@ -282,6 +282,7 @@ typedef struct various_codes {
   PredEntry *pred_throw;
   PredEntry *pred_handle_throw;
   struct array_entry *dyn_array_list;
+  struct DB_STRUCT *db_erased_marker;
   UInt n_of_file_aliases;
   UInt sz_of_file_aliases;
   struct AliasDescS * file_aliases;
@@ -474,6 +475,7 @@ typedef struct various_codes {
 #define  PredThrow                heap_regs->pred_throw
 #define  PredHandleThrow          heap_regs->pred_handle_throw
 #define  DynArrayList             heap_regs->dyn_array_list
+#define  DBErasedMarker           heap_regs->db_erased_marker
 #define  NOfFileAliases           heap_regs->n_of_file_aliases
 #define  SzOfFileAliases          heap_regs->sz_of_file_aliases
 #define  FileAliases              heap_regs->file_aliases

Makefile.in

@@ -90,7 +90,7 @@ TEXI2PDF=texi2pdf
 #4.1VPATH=@srcdir@:@srcdir@/OPTYap
 CWD=$(PWD)
 #
-VERSION=Yap-4.3.21
+VERSION=Yap-4.3.22
 #
 
 TAG_HEADERS=  Tags_32bits.h Tags_32Ops.h Tags_32LowTag.h\

changes4.3.html

@@ -16,6 +16,14 @@
 
 <h2>Yap-4.3.22:</h2>
 <ul>
+	<li>FIXED: recover space for logical update semantics.</li>
+	<li>FIXED: smash references to deleted entries with logical
+	update semantics.</li>
+	<li>FIXED: make instance of deleted fail for logical
+	update semantics.</li>
+	<li>FIXED: smash references to deleted references for logical
+	update semantics.</li>
+	<li>FIXED: garbage_collect should call do_gc with P, not CP.</li>
 	<li>FIXED: use YAPSHAREDIR as in manual (Ashwin Srinivasan).</li>
 	<li>FIXED: warning message about unify_extension.</li>
 </ul>

docs/yap.tex

@@ -8,8 +8,8 @@
 @c @setchapternewpage odd
 @c %**end of header
 
-@set VERSION 4.3.21
+@set VERSION 4.3.22
-@set EDITION 4.1.1
+@set EDITION 4.2.1
 @set UPDATED January 2002
 
 @c Index for C-Prolog compatible predicate

misc/Yap.spec

@@ -1,6 +1,6 @@
 Name: Yap
 Summary: Prolog Compiler
-Version: 4.3.21
+Version: 4.3.22
 Packager:     Vitor Santos Costa <vitor@cos.ufrj.br>
 Release: 1
 Source: http://www.ncc.up.pt/~vsc/Yap/Yap4.3/%{name}-%{version}.tar.gz