From f609e8b93bcd96372e5fdc39440253ae56097107 Mon Sep 17 00:00:00 2001
From: vsc <vsc@b08c6af1-5177-4d33-ba66-4b1c6b8b522a>
Date: Sun, 22 Feb 2004 00:35:07 +0000
Subject: [PATCH] check read locking on PRWLock

git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@1002 b08c6af1-5177-4d33-ba66-4b1c6b8b522a
---
 C/absmi.c    |  4 ++--
 C/cdmgr.c    | 47 +++++++++++++++++++++++------------------------
 C/compiler.c |  1 +
 C/errors.c   |  4 +++-
 C/exec.c     |  9 +++++----
 5 files changed, 34 insertions(+), 31 deletions(-)

diff --git a/C/absmi.c b/C/absmi.c
index dd94978d6..34892283e 100644
--- a/C/absmi.c
+++ b/C/absmi.c
@@ -1443,11 +1443,11 @@ Yap_absmi(int inp)
       CUT_wait_leftmost();
 #endif /* YAPOR */
       /* need to make the DB stable until I get the new clause */
-      READ_LOCK(((PredEntry *)(PREG->u.ld.p))->PRWLock);
+      READ_LOCK(PREG->u.ld.p->PRWLock);
       CACHE_Y(B);
       PREG = PREG->u.ld.d;
       LOCK(DynamicLock(PREG));
-      READ_UNLOCK(((PredEntry *)(PREG->u.ld.p))->PRWLock);
+      READ_UNLOCK(PREG->u.ld.p->PRWLock);
       restore_yaam_regs(PREG);
       restore_args(PREG->u.ld.s);
 #ifdef FROZEN_STACKS
diff --git a/C/cdmgr.c b/C/cdmgr.c
index 082b194b2..65127970d 100644
--- a/C/cdmgr.c
+++ b/C/cdmgr.c
@@ -2035,11 +2035,13 @@ p_pred_exists(void)
   if (EndOfPAEntr(pe))
     return FALSE;
   READ_LOCK(pe->PRWLock);
-  if (pe->PredFlags & HiddenPredFlag)
-    return(FALSE);
+  if (pe->PredFlags & HiddenPredFlag){
+    READ_UNLOCK(pe->PRWLock);
+    return FALSE;
+  }
   out = (pe->OpcodeOfPred != UNDEF_OPCODE);
   READ_UNLOCK(pe->PRWLock);
-  return(out);
+  return out;
 }
 
 static Int 
@@ -2376,8 +2378,8 @@ search_for_static_predicate_in_use(PredEntry *p, int check_everything)
 	    }
 	  }
 	}
+	READ_UNLOCK(pe->PRWLock);
       }
-      READ_UNLOCK(pe->PRWLock);
       env_ptr = b_ptr->cp_env;
       b_ptr = b_ptr->cp_b;
     }
@@ -3142,6 +3144,12 @@ fetch_next_lu_clause(PredEntry *pe, yamop *i_code, Term th, Term tb, Term tr, ya
     TRAIL_CLREF(cl);	/* So that fail will erase it */
   }
 #endif
+#if defined(YAPOR) || defined(THREADS)
+  if (PP == pe) {
+    PP = NULL;
+    READ_UNLOCK(pe->PRWLock);
+  }
+#endif
 #if defined(YAPOR) || defined(THREADS)
   WPP = NULL;
 #endif
@@ -3210,18 +3218,10 @@ p_log_update_clause(void)
     WRITE_UNLOCK(pe->PRWLock);
   }
 #if defined(YAPOR) || defined(THREADS)
-  if (PP != pe) {
-    READ_LOCK(pe->PRWLock);
-    PP = pe;
-  }
+  READ_LOCK(pe->PRWLock);
+  PP = pe;
 #endif
   ret = fetch_next_lu_clause(pe, pe->cs.p_code.TrueCodeOfPred, t1, ARG3, ARG4, P, TRUE);
-#if defined(YAPOR) || defined(THREADS)
-  if (PP == pe) {
-    PP = NULL;
-    READ_UNLOCK(pe->PRWLock);
-  }
-#endif
   return ret;
 }
 
@@ -3240,6 +3240,12 @@ fetch_next_lu_clause0(PredEntry *pe, yamop *i_code, Term th, Term tb, yamop *cp_
   LogUpdClause *cl;
 
   cl = Yap_FollowIndexingCode(pe, i_code, th, tb, TermNil, NEXTOP(PredLogUpdClause0->CodeOfPred,ld), cp_ptr);
+#if defined(YAPOR) || defined(THREADS)
+  if (PP == pe) {
+    PP = NULL;
+    READ_UNLOCK(pe->PRWLock);
+  }
+#endif
   if (cl == NULL) {
     return FALSE;
   }
@@ -3304,18 +3310,10 @@ p_log_update_clause0(void)
       IPred(pe);
   }
 #if defined(YAPOR) || defined(THREADS)
-  if (PP != pe) {
-    READ_LOCK(pe->PRWLock);
-    PP = pe;
-  }
+  READ_LOCK(pe->PRWLock);
+  PP = pe;
 #endif
   ret = fetch_next_lu_clause0(pe, pe->cs.p_code.TrueCodeOfPred, t1, ARG3, P, TRUE);
-#if defined(YAPOR) || defined(THREADS)
-  if (PP == pe) {
-    PP = NULL;
-    READ_UNLOCK(pe->PRWLock);
-  }
-#endif
   return ret;
 }
 
@@ -3479,6 +3477,7 @@ add_code_in_pred(PredEntry *pp) {
     cl = ClauseCodeToStaticClause(clcode);
     code_end = (char *)cl + Yap_SizeOfBlock((CODEADDR)cl);
     Yap_inform_profiler_of_clause(clcode, (yamop *)code_end, pp);
+    READ_UNLOCK(pp->PRWLock);
     return;
   }
   clcode = pp->cs.p_code.TrueCodeOfPred;
diff --git a/C/compiler.c b/C/compiler.c
index 9b259cf3f..4ba1ed74d 100644
--- a/C/compiler.c
+++ b/C/compiler.c
@@ -571,6 +571,7 @@ c_arg(Int argno, Term t, unsigned int arity, unsigned int level, compiler_struct
       READ_UNLOCK(cglobs->cint.CurrentPred->PRWLock);
       FAIL("can not compile data base reference",TYPE_ERROR_CALLABLE,t);
     } else {
+      READ_UNLOCK(cglobs->cint.CurrentPred->PRWLock);
       Yap_emit((cglobs->onhead ? get_atom_op : put_atom_op), (CELL) t, argno, &cglobs->cint);      
     }
   } else {
diff --git a/C/errors.c b/C/errors.c
index 7f5bcc5e0..222af0e27 100644
--- a/C/errors.c
+++ b/C/errors.c
@@ -109,6 +109,7 @@ DumpActiveGoals (void)
 	  Functor f;
 	  Term mod = TermProlog;
 
+	  READ_UNLOCK(pe->PRWLock);
 	  f = pe->FunctorOfPred;
 	  if (pe->KindOfPE && hidden (NameOfFunctor (f)))
 	    goto next;
@@ -125,9 +126,10 @@ DumpActiveGoals (void)
 	    Yap_plwrite (MkIntTerm (ArityOfFunctor (f)), Yap_DebugPutc, 0);
 	  }
 	  Yap_DebugPutc (Yap_c_error_stream,'\n');
+	} else {
+	  READ_UNLOCK(pe->PRWLock);
 	}
     next:
-      READ_UNLOCK(pe->PRWLock);
       ep = (CELL *) ep[E_E];
     }
   first = 1;
diff --git a/C/exec.c b/C/exec.c
index 1ac5481be..cf40d569a 100644
--- a/C/exec.c
+++ b/C/exec.c
@@ -51,8 +51,10 @@ CallPredicate(PredEntry *pen, choiceptr cut_pt) {
 #ifdef DEPTH_LIMIT
   if (DEPTH <= MkIntTerm(1)) {/* I assume Module==0 is prolog */
     if (pen->ModuleOfPred) {
-      if (DEPTH == MkIntTerm(0))
+      if (DEPTH == MkIntTerm(0)) {
+	READ_UNLOCK(pen->PRWLock);
 	return FALSE;
+      }
       else DEPTH = RESET_DEPTH();
     }
   } else if (pen->ModuleOfPred)
@@ -1349,15 +1351,14 @@ Yap_RunTopGoal(Term t)
   ppe = RepPredProp(pe);
   if (pe != NIL) {
     READ_LOCK(ppe->PRWLock);
-  }
-  if (pe == NIL) {
+  } else if (pe == NIL) {
     /* we must always start the emulator with Prolog code */
     return(FALSE);
   }
+  CodeAdr = ppe->CodeOfPred;
   if (pe != NIL) {
     READ_UNLOCK(ppe->PRWLock);
   }
-  CodeAdr = ppe->CodeOfPred;
   if (Yap_TrailTop - HeapTop < 2048) {
     Yap_PrologMode = BootMode;
     Yap_Error(SYSTEM_ERROR,TermNil,