Runs on test suite wu-ftpd and bind without crashing or producing obvious errors.

[splint.git] / src / constraint.c

/*
** constraint.c
*/

//#define DEBUGPRINT 1

# include <ctype.h> /* for isdigit */
# include "lclintMacros.nf"
# include "basic.h"
# include "cgrammar.h"
# include "cgrammar_tokens.h"

# include "exprChecks.h"
# include "aliasChecks.h"
# include "exprNodeSList.h"
//# include "exprData.i"

/*@i33*/
/*@-fcnuse*/
/*@-assignexpose*/

/*@access exprNode @*/


static /*@notnull@*/  /*@special@*/ constraint constraint_makeNew (void)
     /*@post:isnull result->or, result->orig,  result->generatingExpr, result->fcnPre @*/ /*@defines result->or, result->generatingExpr, result->orig, result->fcnPre @*/;
     
/*  constraint makeConstraintParse (sRef x, lltok relOp, exprNode cconstant) */
     
/*  { */
/*    char *t; */
/*    int c; */
/*    constraint ret; */
/*    ret = constraint_makeNew(); */
/*    llassert (sRef_isValid(x) ); */
/*    if (!sRef_isValid(x)) */
/*      return ret; */
 
    
/*    ret->lexpr = constraintExpr_makeTermsRef (x); */
/*    #warning fix abstraction */

/*    if (relOp.tok == GE_OP) */
/*        ret->ar = GTE; */
/*    else if (relOp.tok == LE_OP) */
/*      ret->ar = LTE; */
/*    else if (relOp.tok == EQ_OP) */
/*      ret->ar = EQ; */
/*    else */
/*      llfatalbug(message ("Unsupported relational operator") ); */


/*    t =  cstring_toCharsSafe (exprNode_unparse(cconstant)); */
/*    c = atoi( t ); */
/*    ret->expr = constraintExpr_makeIntLiteral (c); */

/*    ret->post = TRUE; */
/*    //  ret->orig = ret; */
/*    DPRINTF(("GENERATED CONSTRAINT:")); */
/*    DPRINTF( (message ("%s", constraint_print(ret) ) ) ); */
/*    return ret; */
/*  } */

constraint makeConstraintParse2 (constraintExpr l, lltok relOp, exprNode cconstant)    
{
  char *t;
  int c;
  constraint ret;
  ret = constraint_makeNew();
  llassert (l!=NULL);
      
  ret->lexpr = constraintExpr_copy (l);
  #warning fix abstraction

  if (relOp.tok == GE_OP)
      ret->ar = GTE;
  else if (relOp.tok == LE_OP)
    ret->ar = LTE;
  else if (relOp.tok == EQ_OP)
    ret->ar = EQ;
  else
  llfatalbug(message("Unsupported relational operator") );


  t =  cstring_toCharsSafe (exprNode_unparse(cconstant));
  c = atoi( t );
  ret->expr = constraintExpr_makeIntLiteral (c);

  ret->post = TRUE;
  //  ret->orig = ret;
  DPRINTF(("GENERATED CONSTRAINT:"));
  DPRINTF( (message ("%s", constraint_print(ret) ) ) );
  return ret;
}

bool constraint_same (constraint c1, constraint c2)
{
  
  if (c1->ar != c2->ar)
    return FALSE;

  if (!constraintExpr_similar (c1->lexpr, c2->lexpr) )
    return FALSE;

  if (!constraintExpr_similar (c1->expr, c2->expr) )
    return FALSE;

  return TRUE;
}

constraint makeConstraintParse3 (constraintExpr l, lltok relOp, constraintExpr r)     
{
  constraint ret;
  ret = constraint_makeNew();
  llassert (l !=NULL);
    
  ret->lexpr = constraintExpr_copy (l);
  #warning fix abstraction

  if (relOp.tok == GE_OP)
      ret->ar = GTE;
  else if (relOp.tok == LE_OP)
    ret->ar = LTE;
  else if (relOp.tok == EQ_OP)
    ret->ar = EQ;
  else
  llfatalbug( message("Unsupported relational operator") );

  ret->expr = constraintExpr_copy (r);

  ret->post = TRUE;

  ret->orig = constraint_copy(ret);

  ret = constraint_simplify (ret);
  
  //  ret->orig = ret;
  DPRINTF(("GENERATED CONSTRAINT:"));
  DPRINTF( (message ("%s", constraint_print(ret) ) ) );
  return ret;
}

constraint constraint_copy (constraint c)
{
  constraint ret;

  llassert (constraint_isDefined(c) );
  // TPRINTF((message("Copying constraint %q", constraint_print) ));
  
  ret = constraint_makeNew();
  ret->lexpr = constraintExpr_copy (c->lexpr);
  ret->ar = c->ar;
  ret->expr =  constraintExpr_copy (c->expr);
  ret->post = c->post;
  ret->generatingExpr = exprNode_fakeCopy(c->generatingExpr);
  
  /*@i33 fix this*/
  if (c->orig != NULL)
    ret->orig = constraint_copy (c->orig);
  else
    ret->orig = NULL;

  if (c->or != NULL)
    ret->or = constraint_copy (c->or);
  else
    ret->or = NULL;

  ret->fcnPre = c->fcnPre;
  
  return ret;
}

/*like copy expect it doesn't allocate memory for the constraint*/

void constraint_overWrite (constraint c1, constraint c2) 
{
  llassert (constraint_isDefined(c1) );

  llassert (c1 != c2);

  DPRINTF((message("OverWriteing constraint %q with %q", constraint_print(c1),
		   constraint_print(c2) ) ));
  
  constraintExpr_free(c1->lexpr);
  constraintExpr_free(c1->expr);
  
  c1->lexpr = constraintExpr_copy (c2->lexpr);
  c1->ar = c2->ar;
  c1->expr =  constraintExpr_copy (c2->expr);
  c1->post = c2->post;

  if (c1->orig != NULL)
    constraint_free (c1->orig);

  if (c2->orig != NULL)
    c1->orig = constraint_copy (c2->orig);
  else
    c1->orig = NULL;

  /*@i33 make sure that the or is freed correctly*/
  if (c1->or != NULL)
    constraint_free (c1->or);

  if (c2->or != NULL)
    c1->or = constraint_copy (c2->or);
  else
    c1->or = NULL;

  c1->fcnPre = c2->fcnPre;
  
  c1->generatingExpr = c2->generatingExpr;
}



static /*@notnull@*/  /*@special@*/ constraint constraint_makeNew (void)
     /*@post:isnull result->or, result->orig,  result->generatingExpr, result->fcnPre @*/ /*@defines result->or, result->generatingExpr, result->orig, result->fcnPre @*/
{
  constraint ret;
  ret = dmalloc(sizeof (*ret) );
  ret->lexpr = NULL;
  ret->expr = NULL;
  ret->ar = LT;
  ret->post = FALSE;
  ret->orig = NULL;
  ret->or = NULL;
  ret->generatingExpr = NULL;
  ret->fcnPre = NULL;
  return ret;
}

constraint constraint_addGeneratingExpr (/*@returned@*/ constraint c, exprNode e)
{
    
  if (c->generatingExpr == NULL)
    {
      c->generatingExpr = exprNode_fakeCopy(e);
      DPRINTF ((message ("setting generatingExpr for %s to %s", constraint_print(c), exprNode_unparse(e) )  ));
    }
  else
    {
      DPRINTF ((message ("Not setting generatingExpr for %s to %s", constraint_print(c), exprNode_unparse(e) )  ));
    }
  return c;
}

constraint constraint_origAddGeneratingExpr (/*@returned@*/ constraint c, exprNode e)
{

  if (c->orig != constraint_undefined)
    {
      c->orig = constraint_addGeneratingExpr(c->orig, e);
    }
  else
    {
      DPRINTF ((message ("constraint_origAddGeneratingExpr: Not setting generatingExpr for %s to %s", constraint_print(c), exprNode_unparse(e) )  ));
    }
  return c;
}



constraint constraint_setFcnPre (/*@returned@*/ constraint c )
{

  if (c->orig != constraint_undefined)
    {
      c->orig->fcnPre = TRUE;
    }
  else
    {
      c->fcnPre = TRUE;
      TPRINTF(( message("Warning Setting fcnPre directly") ));
    }
  return c;
}




fileloc constraint_getFileloc (constraint c)
{
  if (exprNode_isDefined(c->generatingExpr) )
    return (fileloc_copy (exprNode_getfileloc (c->generatingExpr) ) );
	    
  return (constraintExpr_getFileloc (c->lexpr) );


}

static bool checkForMaxSet (constraint c)
{
  if (constraintExpr_hasMaxSet(c->lexpr) || constraintExpr_hasMaxSet(c->expr) )
    return TRUE;

  return FALSE;
}

bool constraint_hasMaxSet(constraint c)
{
  if (c->orig != NULL)
    {
      if (checkForMaxSet(c->orig) )
	return TRUE;
    }

  return (checkForMaxSet(c) );
}

constraint constraint_makeReadSafeExprNode ( exprNode po, exprNode ind)
{
  constraint ret = constraint_makeNew();
  //  constraintTerm term;
  po = exprNode_fakeCopy(po);
  ind = exprNode_fakeCopy(ind);
  ret->lexpr = constraintExpr_makeMaxReadExpr(po);
  ret->ar    = GTE;
  ret->expr  = constraintExpr_makeValueExpr (ind);
  ret->post = FALSE;
  return ret;
}

constraint constraint_makeWriteSafeInt (exprNode po, int ind)
{
  constraint ret = constraint_makeNew();

 
  ret->lexpr =constraintExpr_makeMaxSetExpr(po);
  ret->ar = GTE;
  ret->expr =  constraintExpr_makeIntLiteral (ind);
  /*@i1*/return ret;
}

constraint constraint_makeSRefSetBufferSize (sRef s, long int size)
{
 constraint ret = constraint_makeNew();
 ret->lexpr = constraintExpr_makeSRefMaxset (s);
 ret->ar = EQ;
 ret->expr =  constraintExpr_makeIntLiteral ((int)size);
 ret->post = TRUE;
 /*@i1*/return ret;
}

constraint constraint_makeSRefWriteSafeInt (sRef s, int ind)
{
  constraint ret = constraint_makeNew();

 
  ret->lexpr = constraintExpr_makeSRefMaxset ( s );
  ret->ar = GTE;
  ret->expr =  constraintExpr_makeIntLiteral (ind);
  ret->post = TRUE;
  /*@i1*/return ret;
}

/* drl added 01/12/2000
   
  makes the constraint: Ensures index <= MaxRead(buffer) */

constraint constraint_makeEnsureLteMaxRead(exprNode index, exprNode buffer)
{
  constraint ret = constraint_makeNew();

  ret->lexpr = constraintExpr_makeValueExpr (index);
  ret->ar = LTE;
  ret->expr = constraintExpr_makeMaxReadExpr(buffer);
  ret->post = TRUE;
  return ret;
}

constraint constraint_makeWriteSafeExprNode (exprNode po, exprNode ind)
{
  constraint ret = constraint_makeNew();

 
  ret->lexpr =constraintExpr_makeMaxSetExpr(po);
  ret->ar = GTE;
  ret->expr =  constraintExpr_makeValueExpr (ind);
  /*@i1*/return ret;
}


constraint constraint_makeReadSafeInt ( exprNode po, int ind)
{
  constraint ret = constraint_makeNew();

  po = exprNode_fakeCopy(po);
  
  ret->lexpr = constraintExpr_makeMaxReadExpr(po);
  ret->ar    = GTE;
  ret->expr  = constraintExpr_makeIntLiteral (ind);
  ret->post = FALSE;
  return ret;
}

constraint constraint_makeSRefReadSafeInt (sRef s, int ind)
{
  constraint ret = constraint_makeNew();

 
  ret->lexpr = constraintExpr_makeSRefMaxRead (s );
  ret->ar = GTE;
  ret->expr =  constraintExpr_makeIntLiteral (ind);
  ret->post = TRUE;
  /*@i1*/return ret;
}

constraint constraint_makeEnsureMaxReadAtLeast (exprNode e1, exprNode t2, fileloc sequencePoint)
{
  constraint ret;

  e1 = exprNode_fakeCopy (e1);
  t2 = exprNode_fakeCopy (t2);
  
  ret = constraint_makeReadSafeExprNode(e1, t2);

  ret->lexpr = constraintExpr_setFileloc (ret->lexpr, sequencePoint);
  
  ret->post = TRUE;  

  //  fileloc_incColumn (ret->lexpr->term->loc);
  return ret;
}

static constraint constraint_makeEnsuresOpConstraintExpr (/*@only@*/ constraintExpr c1, /*@only@*/ constraintExpr c2, fileloc sequencePoint,  arithType  ar)
{

  constraint ret;
  
  llassert(c1 && c2);
  //  llassert(sequencePoint);

  ret = constraint_makeNew();
  
  ret->lexpr = c1;
  ret->ar = ar;
  ret->post = TRUE;
  ret->expr =  c2;
  ret->lexpr = constraintExpr_setFileloc (ret->lexpr, sequencePoint);
  return ret;
}

static constraint constraint_makeEnsuresOp (exprNode e1, exprNode e2, fileloc sequencePoint,  arithType  ar)
{
  constraintExpr c1, c2;
  constraint ret;
  exprNode e;

  if (! (e1 && e2) )
    {
      llcontbug((message("null exprNode, Exprnodes are %s and %s",
		       exprNode_unparse(e1), exprNode_unparse(e2) )
	       ));
    }

  //  llassert (sequencePoint);
  
  e  =  exprNode_fakeCopy(e1);
  c1 =  constraintExpr_makeValueExpr (e);
  
  e  =  exprNode_fakeCopy(e2);
  c2 =  constraintExpr_makeValueExpr (e);

  ret = constraint_makeEnsuresOpConstraintExpr (c1, c2, sequencePoint, ar);
  
  return ret;
}


/* make constraint ensures e1 == e2 */

constraint constraint_makeEnsureEqual (exprNode e1, exprNode e2, fileloc sequencePoint)
{
  return ( constraint_makeEnsuresOp (e1, e2, sequencePoint, EQ) );
}

/*make constraint ensures e1 < e2 */
constraint constraint_makeEnsureLessThan (exprNode e1, exprNode e2, fileloc sequencePoint)
{
  constraintExpr t1, t2;

  t1 = constraintExpr_makeValueExpr (e1);
  t2 = constraintExpr_makeValueExpr (e2);

  /*change this to e1 <= (e2 -1) */

  t2 = constraintExpr_makeDecConstraintExpr (t2);
  
 return ( constraint_makeEnsuresOpConstraintExpr (t1, t2, sequencePoint, LTE) );
}

constraint constraint_makeEnsureLessThanEqual (exprNode e1, exprNode e2, fileloc sequencePoint)
{
 return ( constraint_makeEnsuresOp (e1, e2, sequencePoint, LTE) );
}

constraint constraint_makeEnsureGreaterThan (exprNode e1, exprNode e2, fileloc sequencePoint)
{
  constraintExpr t1, t2;

  t1 = constraintExpr_makeValueExpr (e1);
  t2 = constraintExpr_makeValueExpr (e2);


  /* change this to e1 >= (e2 + 1) */
  t2 = constraintExpr_makeIncConstraintExpr (t2);
  
  
 return ( constraint_makeEnsuresOpConstraintExpr (t1, t2, sequencePoint, GTE) );
}

constraint constraint_makeEnsureGreaterThanEqual (exprNode e1, exprNode e2, fileloc sequencePoint)
{
 return ( constraint_makeEnsuresOp (e1, e2, sequencePoint, GTE) );
}


exprNode exprNode_copyConstraints (/*@returned@*/ exprNode dst, exprNode src)
{
  constraintList_free(dst->ensuresConstraints);
  constraintList_free(dst->requiresConstraints);
  constraintList_free(dst->trueEnsuresConstraints);
  constraintList_free(dst->falseEnsuresConstraints);
  
  dst->ensuresConstraints = constraintList_copy (src->ensuresConstraints );
  dst->requiresConstraints = constraintList_copy (src->requiresConstraints );
  dst->trueEnsuresConstraints = constraintList_copy (src->trueEnsuresConstraints );
  dst->falseEnsuresConstraints = constraintList_copy (src->falseEnsuresConstraints );
  return dst;
}

constraint constraint_makeMaxSetSideEffectPostDecrement (exprNode e, fileloc sequencePoint)
{
  constraint ret = constraint_makeNew();
  //constraintTerm term;

  e = exprNode_fakeCopy(e);
  ret->lexpr = constraintExpr_makeValueExpr (e);
  ret->ar = EQ;
  ret->post = TRUE;
  ret->expr =  constraintExpr_makeValueExpr (e);
  ret->expr =  constraintExpr_makeDecConstraintExpr (ret->expr);

  ret->lexpr = constraintExpr_setFileloc (ret->lexpr, sequencePoint);
//   fileloc_incColumn (  ret->lexpr->term->loc);
//   fileloc_incColumn (  ret->lexpr->term->loc);
  return ret;
}
constraint constraint_makeMaxSetSideEffectPostIncrement (exprNode e, fileloc sequencePoint)
{
  constraint ret = constraint_makeNew();
  //constraintTerm term;

  e = exprNode_fakeCopy(e);
  ret->lexpr = constraintExpr_makeValueExpr (e);
  ret->ar = EQ;
  ret->post = TRUE;
  ret->expr =  constraintExpr_makeValueExpr (e);
  ret->expr =  constraintExpr_makeIncConstraintExpr (ret->expr);

  ret->lexpr = constraintExpr_setFileloc (ret->lexpr, sequencePoint);
//   fileloc_incColumn (  ret->lexpr->term->loc);
//   fileloc_incColumn (  ret->lexpr->term->loc);
  return ret;
}


void constraint_free (/*@only@*/ /*@notnull@*/ constraint c)
{
  llassert(constraint_isDefined (c) );


  if (constraint_isDefined(c->orig) )
    constraint_free (c->orig);
  if ( constraint_isDefined(c->or) )
    constraint_free (c->or);

  
  constraintExpr_free(c->lexpr);
  constraintExpr_free(c->expr);

  c->orig = NULL;
  c->or = NULL;
  c->lexpr = NULL;
  c->expr  = NULL;

  free (c);
  
}


// constraint constraint_makeMaxReadSideEffectPostIncrement (exprNode e, fileloc sequencePoint)
// {
//   constraint ret = constraint_makeNew();
//   //constraintTerm term;

//   e = exprNode_fakeCopy(e);
//   ret->lexpr = constraintExpr_makeMaxReadExpr(e);
//   ret->ar = EQ;
//   ret->post = TRUE;
//   ret->expr = constraintExpr_makeIncConstraintExpr (e);
//   ret->lexpr = constraintExpr_setFileLoc (ret->lexpr, sequencePoint);
//   return ret;
// }


cstring arithType_print (arithType ar) /*@*/
{
  cstring st = cstring_undefined;
  switch (ar)
    {
    case LT:
      st = cstring_makeLiteral (" < ");
      break;
    case	LTE:
      st = cstring_makeLiteral (" <= ");
      break;
    case 	GT:
      st = cstring_makeLiteral (" > ");
      break;
    case 	GTE:
      st = cstring_makeLiteral (" >= ");
      break;
    case	EQ:
      st = cstring_makeLiteral (" == ");
      break;
    case	NONNEGATIVE:
      st = cstring_makeLiteral (" NONNEGATIVE ");
      break;
    case	POSITIVE:
      st = cstring_makeLiteral (" POSITIVE ");
      break;
    default:
      llassert(FALSE);
      break;
    }
  return st;
}

void constraint_printError (constraint c, fileloc loc)
{
  cstring string;
  fileloc errorLoc, temp;
  
  string = constraint_printDetailed (c);

  errorLoc = loc;

  loc = NULL;

  temp = constraint_getFileloc(c);

  if (fileloc_isDefined(temp) )
    {
      errorLoc = temp;
      
      if (c->post)
	{
	  voptgenerror (FLG_FUNCTIONPOST, string, errorLoc);
	}
      else
	{
	  voptgenerror (FLG_FUNCTIONCONSTRAINT, string, errorLoc);
	}
      fileloc_free(temp);
    }
  else
    {
      if (c->post)
	{
	  voptgenerror (FLG_FUNCTIONPOST, string, errorLoc);
	}
      else
	{
	  voptgenerror (FLG_FUNCTIONCONSTRAINT, string, errorLoc);
	}
    }
}


cstring constraint_printDeep (constraint c)
{
  cstring st = cstring_undefined;

  st = constraint_print(c);

  if (c->orig != constraint_undefined)
    {
      if (!c->post)
	{
	  if (c->orig->fcnPre)
	    st = cstring_concatFree(st, (message(" derived from %s precondition: %q", exprNode_unparse(c->orig->generatingExpr), constraint_printDeep(c->orig) )
					 ) );
	  else
	    st = cstring_concatFree(st,(message(" needed to satisfy %q",
						constraint_printDeep(c->orig) )
					) );
	  
	}
      else
	{
	  st = cstring_concatFree(st,(message("derived from: %q",
					      constraint_printDeep(c->orig) )
				      ) );
	}
    }

  return st;  

}

cstring  constraint_printDetailed (constraint c)
{
  cstring st = cstring_undefined;

  if (!c->post)
    {
      st = message ("Unresolved constraint:\nLclint is unable to resolve %q", constraint_printDeep (c) );
    }
  else
    {
      st = message ("Block Post condition:\nThis function block has the post condition %q", constraint_printDeep (c) );
    }

  if (context_getFlag (FLG_CONSTRAINTLOCATION) )
    {
      cstring temp;
      // llassert (c->generatingExpr);
      temp = message ("\nOriginal Generating expression %q: %s\n", fileloc_unparse( exprNode_getfileloc (c->generatingExpr) ),
		      exprNode_unparse(c->generatingExpr) );
      st = cstring_concatFree (st, temp);

      if (constraint_hasMaxSet(c) )
	{
	  temp = message ("\nHas MaxSet\n");
	  st = cstring_concatFree (st, temp);
	}
    }
  return st;
}

/*@only@*/ cstring  constraint_print (constraint c) /*@*/
{
  cstring st = cstring_undefined;
  cstring type = cstring_undefined;
  llassert (c !=NULL);
  if (c->post)
    {
      type = cstring_makeLiteral ("Ensures: ");
    }
  else
    {
      type = cstring_makeLiteral ("Requires: ");
    }
  st = message ("%q: %q %q %q",
		type,
		constraintExpr_print (c->lexpr),
		arithType_print(c->ar),
		constraintExpr_print(c->expr)
		);
  return st;
}

cstring  constraint_printOr (constraint c) /*@*/
{
  cstring ret;
  constraint temp;

  ret = cstring_undefined;
  temp = c;

  ret = cstring_concatFree (ret, constraint_print(temp) );

  temp = temp->or;
  
  while ( constraint_isDefined(temp) ) 
    {
      ret = cstring_concatFree (ret, cstring_makeLiteral (" OR ") );
      ret = cstring_concatFree (ret, constraint_print(temp) );
      temp = temp->or;
    }

  return ret;

}

/*@only@*/ constraint constraint_doSRefFixBaseParam (/*@returned@*/ /*@only@*/ constraint precondition,
						   exprNodeList arglist)
{
  precondition->lexpr = constraintExpr_doSRefFixBaseParam (precondition->lexpr,
							   arglist);
  precondition->expr = constraintExpr_doSRefFixBaseParam (precondition->expr,
							   arglist);

  return precondition;
}


constraint constraint_doFixResult (constraint postcondition, exprNode fcnCall)
{
  postcondition = constraint_copy (postcondition);
  postcondition->lexpr = constraintExpr_doFixResult (postcondition->lexpr, fcnCall);
  postcondition->expr = constraintExpr_doFixResult (postcondition->expr, fcnCall);

  return postcondition;
}

/*@only@*/ constraint constraint_doSRefFixConstraintParam (constraint precondition,
						   exprNodeList arglist)
{

  precondition = constraint_copy (precondition);
  precondition->lexpr = constraintExpr_doSRefFixConstraintParam (precondition->lexpr, arglist);
  precondition->expr = constraintExpr_doSRefFixConstraintParam (precondition->expr, arglist);

  precondition->fcnPre = FALSE;
  return precondition;
}

// bool constraint_hasTerm (constraint c, constraintTerm term)
// {
//   DPRINTF((message ("Constraint %s", constraint_print (c) ) ) );
  
//   if (constraintExpr_includesTerm (c->lexpr, term) )
//     return TRUE;

//   if (constraintExpr_includesTerm (c->expr, term) )
//     return TRUE;

//   return FALSE;
// }

constraint constraint_preserveOrig (/*@returned@*/ constraint c) /*@modifies c @*/
{

  DPRINTF( (message("Doing constraint_preserverOrig for %q ", constraint_printDetailed(c) ) ));
  
  if (c->orig == constraint_undefined)
    c->orig = constraint_copy (c);

  else if (c->orig->fcnPre)
    {
      constraint temp;
      
      temp = c->orig;
      
      /* avoid infinite loop */
      c->orig = NULL;
      c->orig = constraint_copy (c);
      if (c->orig->orig == NULL)
	c->orig->orig = temp;
      else
	llcontbug((message("Expected c->orig->orig to be null" ) ));
    }
  else
    {
      DPRINTF( (message("Not changing constraint") ));
    }
  
  DPRINTF( (message("After Doing constraint_preserverOrig for %q ", constraint_printDetailed(c) ) ));

  return c;
}
/*@=fcnuse*/
/*@=assignexpose*/
/*@=czechfcns@*/

constraint constraint_togglePost (/*@returned@*/ constraint c)
{
  c->post = !c->post;
  return c;
}