make gc work better with globals and even lots of globals

git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@1940 b08c6af1-5177-4d33-ba66-4b1c6b8b522a

C/globals.c

@@ -296,26 +296,28 @@ GrowArena(Term arena, CELL *pt, UInt old_size, UInt size, UInt arity)
 	return FALSE;
       }
       arena = XREGS[arity+1];
+      /* we don't know if the GC added junk on top of the global */
+      pt = ArenaLimit(arena);
+      return GrowArena(arena, pt, old_size, size, arity);
     }
     adjust_cps(size);
     H += size;
   } else {
     XREGS[arity+1] = arena;
-    if ((size=Yap_InsertInGlobal(pt, size*sizeof(CELL)))==0) {
-      return FALSE;
-    }
-    size = size/sizeof(CELL);
-    arena = XREGS[arity+1];
-#if 0
     /* try to recover some room  */
-    if (arena == GlobalArena) {
+    if (arena == GlobalArena && 10*(pt-H0) > 8*(H-H0)) {
-      if (!Yap_gc(arity+1, ENV, P)) {
+      if (!Yap_gcl(size*sizeof(CELL), arity+1, ENV, P)) {
 	Yap_Error(OUT_OF_STACK_ERROR,TermNil,Yap_ErrorMessage);
 	return FALSE;
       }
     }
     arena = XREGS[arity+1];
-#endif
+    pt = ArenaLimit(arena);
+    if ((size=Yap_InsertInGlobal(pt, size*sizeof(CELL)))==0) {
+      return FALSE;
+    }
+    size = size/sizeof(CELL);
+    arena = XREGS[arity+1];
   }
   CreateNewArena(ArenaPt(arena), size+old_size);
   return TRUE;

C/heapgc.c

@@ -417,6 +417,17 @@ GC_NEW_MAHASH(gc_ma_hash_entry *top) {
 
 /* find all accessible objects on the heap and squeeze out all the rest */
 
+static void
+check_pr_trail(tr_fr_ptr trp)
+{
+  if ((tr_fr_ptr)Yap_TrailTop-TR < 1024) {
+    if (!Yap_growtrail(0, TRUE) || TRUE) {
+      /* could not find more trail */
+      save_machine_regs();
+      longjmp(Yap_gc_restore, 2);
+    }
+  }
+}
 
 /* push the active registers onto the trail for inclusion during gc */
 
@@ -432,10 +443,12 @@ push_registers(Int num_regs, yamop *nextop)
   TrailTerm(TR++) = GlobalArena;
   TrailTerm(TR++) = GlobalDelayArena;
   while (al) {
+    check_pr_trail(TR);
     TrailTerm(TR++) = al->ValueOfVE;
     al = al->NextAE;
   }
   while (gl) {
+    check_pr_trail(TR);
     TrailTerm(TR++) = gl->global;
     gl = gl->NextGE;
   }
@@ -445,12 +458,14 @@ push_registers(Int num_regs, yamop *nextop)
       for (i=0; i < arity; i++) {
 	Term tlive  = sal->ValueOfVE.lterms[i].tlive;
 	if (!IsVarTerm(tlive) || !IsUnboundVar(&sal->ValueOfVE.lterms[i].tlive)) {
+	  check_pr_trail(TR);
 	  TrailTerm(TR++) = tlive;
 	}
       }
     }
     sal = sal->NextAE;
   }
+  check_pr_trail(TR);
   TrailTerm(TR) = GcGeneration;
   TR++;
   TrailTerm(TR) = GcPhase;
@@ -461,8 +476,10 @@ push_registers(Int num_regs, yamop *nextop)
   TrailTerm(TR+2) = DelayedVars;
   TR += 3;
 #endif
-  for (i = 1; i <= num_regs; i++)
+  for (i = 1; i <= num_regs; i++) {
+    check_pr_trail(TR);
     TrailTerm(TR++) = (CELL) XREGS[i];
+  }
   /* push any live registers we might have hanging around */
   if (nextop->opc == Yap_opcode(_move_back) ||
       nextop->opc == Yap_opcode(_skip)) {
@@ -478,6 +495,7 @@ push_registers(Int num_regs, yamop *nextop)
 	  lab++;
 	}
 	if (curr & 1) {
+	  check_pr_trail(TR);
 	  TrailTerm(TR++) = XREGS[i];
 	}
 	curr >>= 1;
@@ -3668,13 +3686,9 @@ do_gc(Int predarity, CELL *current_env, yamop *nextop)
 
   gc_phase = (UInt)IntegerOfTerm(Yap_ReadTimedVar(GcPhase));
   /* old HGEN are not very reliable, but still may have data to recover */
-#ifdef FIX
   if (gc_phase != GcCurrentPhase) {
     HGEN = H0;
   }
-#else
-  HGEN = H0;
-#endif
   /*  fprintf(stderr,"HGEN is %ld, %p, %p/%p\n", IntegerOfTerm(Yap_ReadTimedVar(GcGeneration)), HGEN, H,H0);*/
   OldTR = (tr_fr_ptr)(old_TR = TR);
   push_registers(predarity, nextop);
@@ -3724,10 +3738,8 @@ do_gc(Int predarity, CELL *current_env, yamop *nextop)
   pop_registers(predarity, nextop);
   TR = new_TR;
   /*  fprintf(Yap_stderr,"NEW HGEN %ld (%ld)\n", H-H0, HGEN-H0);*/
-#ifdef FIX
   Yap_UpdateTimedVar(GcGeneration, MkIntegerTerm(H-H0));
   Yap_UpdateTimedVar(GcPhase, MkIntegerTerm(GcCurrentPhase));
-#endif
   c_time = Yap_cputime();
   if (gc_verbose) {
     fprintf(Yap_stderr, "%%   Compress: took %g sec\n", (double)(c_time-time_start)/1000);

changes-5.1.html

@@ -17,6 +17,7 @@
 
 <h2>Yap-5.1.3:</h2>
 <ul>
+<li> FIXED: overflow while gc was storing pointers in trail  (obs from Angelika Kimmig).</li>
 <li> FIXED: implement directive encoding/1 (obs from Paulo Moura).</li>
 <li> UPGRADED: to current JPL.</li>
 <li> FIXED: incremental garbage collection conflicts with global variables (disable it for now).</li>