[splint.git] / src / aliasTable.c

/*
** Splint - annotation-assisted static program checker
** Copyright (C) 1994-2003 University of Virginia,
**         Massachusetts Institute of Technology
**
** This program is free software; you can redistribute it and/or modify it
** under the terms of the GNU General Public License as published by the
** Free Software Foundation; either version 2 of the License, or (at your
** option) any later version.
** 
** This program is distributed in the hope that it will be useful, but
** WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
** General Public License for more details.
** 
** The GNU General Public License is available from http://www.gnu.org/ or
** the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
** MA 02111-1307, USA.
**
** For information on splint: info@splint.org
** To report a bug: splint-bug@splint.org
** For more information: http://www.splint.org
*/
/*
** aliasTable.c
*/

# include "splintMacros.nf"
# include "basic.h"

/*@constant int ATINVALID; @*/
# define ATINVALID -1

static sRefSet
  aliasTable_canAliasAux (aliasTable p_s, sRef p_sr, int p_lim) /*@*/ ;
static sRefSet
  aliasTable_aliasedByLimit (aliasTable p_s, sRef p_sr, int p_lim) /*@*/ ;
static sRefSet 
  aliasTable_aliasedByAux (aliasTable p_s, sRef p_sr, int p_lim) /*@*/ ;

aliasTable
aliasTable_new ()
{
  return (aliasTable_undefined);
}

static /*@only@*/ /*@notnull@*/ aliasTable
aliasTable_newEmpty (void)
{
  aliasTable s = (aliasTable) dmalloc (sizeof (*s));
  
  s->nelements = 0;
  s->nspace = aliasTableBASESIZE;
  s->keys     = (sRef *) dmalloc (sizeof (*s->keys) * aliasTableBASESIZE);
  s->values   = (sRefSet *) dmalloc (sizeof (*s->values) * aliasTableBASESIZE);
  
  return (s);
}

static void
aliasTable_grow (/*@notnull@*/ aliasTable s)
{
  int i;
  o_sRefSet *oldvalues = s->values;
  sRef    *oldkeys = s->keys;
  
  s->nspace += aliasTableBASESIZE; 

  s->values = (sRefSet *) dmalloc (sizeof (*s->values)
				   * (s->nelements + s->nspace));
  s->keys = (sRef *) dmalloc (sizeof (*s->keys) * (s->nelements + aliasTableBASESIZE));

  if (s->keys == (sRef *) 0 || s->values == (sRefSet *)0)
    {
      llfatalerror (cstring_makeLiteral ("aliasTable_grow: out of memory!"));
    }

  for (i = 0; i < s->nelements; i++)
    {
      s->values[i] = oldvalues[i];
      s->keys[i] = oldkeys[i];
    }
  
  sfree (oldvalues);
  sfree (oldkeys);
}

static int aliasTable_lookupRefs (/*@notnull@*/ aliasTable s, sRef sr)
{
  int i;

  
  for (i = 0; i < aliasTable_size (s); i++)
    {
      if (sRef_same (sr, s->keys[i])) 
	{
	  return i;
	}
    }

  return ATINVALID;
}

/*
** sr aliases al (and anything al aliases!)
*/

aliasTable
aliasTable_addMustAlias (/*@returned@*/ aliasTable s,
			 /*@exposed@*/ sRef sr,
			 /*@exposed@*/ sRef al)
{
  int ind;
  sRefSet ss;
  
  llassert (NOALIAS (sr, al));
  
  DPRINTF (("Adding alias: %s / %s", sRef_unparseFull (sr),
	    sRef_unparseFull (al)));

  if (aliasTable_isUndefined (s))
    {
      s = aliasTable_newEmpty ();
      ind = ATINVALID;
    }
  else
    {
      ind = aliasTable_lookupRefs (s, sr);
    }
  
  ss = aliasTable_canAlias (s, al); 
  DPRINTF (("Previous aliases: %s", sRefSet_unparse (ss)));
  
  if (ind == ATINVALID)
    {
      if (s->nspace <= 0) {
	aliasTable_grow (s);
      }

      s->nspace--;
      s->keys[s->nelements] = sr;
      s->values[s->nelements] = sRefSet_single (al); 
      ind = s->nelements;
      s->nelements++;      
    }
  else
    {
      s->values[ind] = sRefSet_insert (s->values[ind], al); 
    }
  
  s->values[ind] = sRefSet_unionExcept (s->values[ind], ss, s->keys[ind]); 
  DPRINTF (("New aliases: %s", sRefSet_unparse (s->values[ind])));

  sRefSet_free (ss);
  return s;
}

static aliasTable 
  aliasTable_addSet (/*@returned@*/ aliasTable s,
		     /*@exposed@*/ sRef key, /*@only@*/ sRefSet value)
{
  if (!sRefSet_isEmpty (value))
    {
      if (aliasTable_isUndefined (s))
	{
	  s = aliasTable_newEmpty ();
	}
      else
	{
	  if (s->nspace <= 0)
	    {
	      aliasTable_grow (s);
	    }
	}

      s->nspace--;
      s->keys[s->nelements] = key;
      s->values[s->nelements] = value;
      s->nelements++;      
    }
  else
    {
      sRefSet_free (value);
    }

  return s;
}

/*
** When aliases are cleared:
**
**    o remove all entries for sr
**    o replace all aliases for things which alias sr with sr's aliases
**
** Clear aliases for sr; if sr is a direct param reference, clear its aliases too.
*/

static void aliasTable_clearAliasesAux (/*@notnull@*/ aliasTable p_s, sRef p_sr)
   /*@modifies p_s@*/ ;

void aliasTable_clearAliases (aliasTable s, sRef sr)
{
  if (aliasTable_isUndefined (s))
    {
      return;
    }
  else
    {
      sRef rb = sRef_getRootBase (sr);

            
      if (!sRef_isCvar (sr) && sRef_isLocalVar (rb))
	{
	  int ind = aliasTable_lookupRefs (s, rb);
	  
	  if (ind != ATINVALID)
	    {
	      sRefSet al = s->values[ind];
	      
	      	      
	      sRefSet_realElements (al, el)
		{
		  		  
		  if (sRef_isParam (el))
		    {
		      if (sRef_sameName (el, rb))
			{
			  sRef fb = sRef_fixBase (sr, el); 

			  aliasTable_clearAliasesAux (s, fb); 
			}
		    }
		} end_sRefSet_realElements ;
	    }
	}
      
      aliasTable_clearAliasesAux (s, sr); 
    }  
}

static
void aliasTable_clearAliasesAux (/*@notnull@*/ aliasTable s, sRef sr)
{
  int i;
  
  for (i = 0; i < s->nelements; i++)
    {
      sRef key = s->keys[i];
      
      if (sRef_includedBy (key, sr))
	{
	  sRefSet_clear (s->values[i]);
	}
      else
	{
	  (void) sRefSet_deleteBase (s->values[i], sr);   
	}
    }
}

/*
** returns set of all sRefs that must alias sr (but are different from sr)
*/

static /*@only@*/ sRefSet aliasTable_aliasedByAux (aliasTable s, sRef sr, int lim)
{
  static bool hadWarning = FALSE;
  sRefSet res = sRefSet_undefined;
  int i;

  llassert (!sRef_isConj (sr));
  
  
  if (aliasTable_isUndefined (s) || lim >= ALIASSEARCHLIMIT)
    {
      if (lim >= ALIASSEARCHLIMIT && !hadWarning)
	{
	  llquietbug
	    (message ("Alias search limit exceeded, checking %q. "
		      "This either means there is a variable with at least "
		      "%d indirections, or there is a bug in Splint.",
		      sRef_unparse (sr),
		      ALIASSEARCHLIMIT));
	  
	  hadWarning = TRUE;
	}

      return sRefSet_undefined;
    }
  else
    {
      sRefSet abl;

      if (sRef_isPointer (sr))
	{
	  abl = aliasTable_aliasedByLimit (s, sRef_getBase (sr), lim);
	  res = sRefSet_addIndirection (abl);
	}
      else if (sRef_isAddress (sr))
	{
	  abl = aliasTable_aliasedByLimit (s, sRef_getBase (sr), lim);
	  res = sRefSet_removeIndirection (abl);
	}
      else if (sRef_isField (sr))
	{
	  abl = aliasTable_aliasedByLimit (s, sRef_getBase (sr), lim);
	  res = sRefSet_accessField (abl, sRef_getField (sr));
	}
      else if (sRef_isArrayFetch (sr))
	{
	  abl = aliasTable_aliasedByLimit (s, sRef_getBase (sr), lim);

	  if (sRef_isIndexKnown (sr))
	    {
	      int idx = sRef_getIndex (sr);
	      
	      res = sRefSet_fetchKnown (abl, idx);
	    }
	  else
	    {
	      res = sRefSet_fetchUnknown (abl);
	    }
	}
      else
	{
	  abl = sRefSet_undefined;
	}

      sRefSet_free (abl);
    }

  for (i = 0; i < s->nelements; i++)
    {
      sRef elem = s->keys[i];
      
      if (!sRef_same (sr, elem)) /* was sameName */
	{
	  	  
	  sRefSet_realElements (s->values[i], current)
	    {
	      	      
	      if (sRef_similar (sr, current))
		{
		  		  		  res = sRefSet_insert (res, sRef_fixOuterRef (elem));
		  /*@innerbreak@*/ break;
		}
	    } end_sRefSet_realElements;
	} 
    }
  
    return res;
}

static /*@only@*/ sRefSet aliasTable_aliasedByLimit (aliasTable s, sRef sr, int lim)
{
  sRefSet res;
  
  
  if (sRef_isConj (sr))
    {
      res = sRefSet_unionFree (aliasTable_aliasedByLimit (s, sRef_getConjA (sr), lim),
			       aliasTable_aliasedByLimit (s, sRef_getConjB (sr), lim));
    }
  else
    {
      res = aliasTable_aliasedByAux (s, sr, lim + 1);
    }
  
    return res;
}

/*@only@*/ sRefSet aliasTable_aliasedBy (aliasTable s, sRef sr)
{ 
  if (sRef_isConj (sr))
    {
      return (sRefSet_unionFree (aliasTable_aliasedBy (s, sRef_getConjA (sr)),
				 aliasTable_aliasedBy (s, sRef_getConjB (sr))));
    }

  return (aliasTable_aliasedByAux (s, sr, 0));
}

/*@only@*/ sRefSet aliasTable_canAlias (aliasTable s, sRef sr)
{
  sRefSet res;

    
  if (sRef_isConj (sr))
    {
      res = sRefSet_unionFree (aliasTable_canAlias (s, sRef_getConjA (sr)),
			       aliasTable_canAlias (s, sRef_getConjB (sr)));
    }
  else
    {
      res = aliasTable_canAliasAux (s, sr, 0);
          }

    return res;
}

/*
** need to limit the depth of aliasing searches 
*/

static /*@only@*/ sRefSet aliasTable_canAliasLimit (aliasTable s, sRef sr, int lim)
{
  sRefSet res;
  
  if (sRef_isConj (sr))
    {
      sRefSet a = aliasTable_canAliasLimit (s, sRef_getConjA (sr), lim);
      sRefSet b = aliasTable_canAliasLimit (s, sRef_getConjB (sr), lim);

      res = sRefSet_unionFree (a, b);
    }
  else
    {
      res = aliasTable_canAliasAux (s, sr, lim + 1);
    }
  
  return res;
}

static /*@only@*/ sRefSet 
  aliasTable_canAliasAux (aliasTable s, sRef sr, int lim)
{
  static bool hadWarning = FALSE;
  llassert (!sRef_isConj (sr));
  
  
  if (aliasTable_isUndefined (s) || lim >= ALIASSEARCHLIMIT)
    {
      if (lim >= ALIASSEARCHLIMIT && !hadWarning)
	{
	  llquietbug
	    (message ("Alias search limit exceeded, checking %q. "
		      "This either means there is a variable with at least "
		      "%d indirections, or there is a bug in Splint.",
		      sRef_unparse (sr),
		      ALIASSEARCHLIMIT));
	  
	  hadWarning = TRUE;
	}

      return sRefSet_undefined;
    }
  else
    {
      int ind = aliasTable_lookupRefs (s, sr);

      if (sRef_isPointer (sr) || sRef_isAddress (sr) || sRef_isField (sr)
	  || sRef_isArrayFetch (sr))
	{
	  sRef base = sRef_getBase (sr);
	  sRefSet tmp = aliasTable_canAliasLimit (s, base, lim);
	  sRefSet ret;

	  if (sRef_isPointer (sr))
	    {
	      ret = sRefSet_addIndirection (tmp); 
	    }
	  else if (sRef_isAddress (sr))
	    {
	      ret = sRefSet_removeIndirection (tmp);
	    }
	  else if (sRef_isField (sr))
	    {
	      ret = sRefSet_accessField (tmp, sRef_getField (sr));
	    }
	  else if (sRef_isArrayFetch (sr))
	    {
	      if (sRef_isIndexKnown (sr))
		{
		  ret = sRefSet_fetchKnown (tmp, sRef_getIndex (sr));
		}
	      else
		{
		  ret = sRefSet_fetchUnknown (tmp);
		}
	    }
	  else
	    {
	      BADBRANCH;
	    }

	  if (ind != ATINVALID)
	    {
	      ret = sRefSet_union (ret, s->values[ind]);
	    }
	  
	  sRefSet_free (tmp);
	  return ret;
	}
      
      if (ind == ATINVALID) return sRefSet_undefined;      
      
      return sRefSet_newCopy (s->values[ind]);
    }
}

aliasTable aliasTable_copy (aliasTable s)
{
  if (aliasTable_isEmpty (s))
    {
      return aliasTable_undefined;
    }
  else
    {
      aliasTable t = (aliasTable) dmalloc (sizeof (*s));
      int i;

      t->nelements = s->nelements;
      t->nspace = 0;
      t->keys = (sRef *) dmalloc (sizeof (*s->keys) * s->nelements);
      t->values = (sRefSet *) dmalloc (sizeof (*s->values) * t->nelements);
        
      for (i = 0; i < s->nelements; i++)
	{
	  t->keys[i] = s->keys[i];
	  t->values[i] = sRefSet_newCopy (s->values[i]);
	}

      return t;
    }
}

static void
aliasTable_levelPrune (aliasTable s, int lexlevel)
{
  
  
  if (aliasTable_isEmpty (s))
    {
      return;
    }
  else
    {
      int i;
      int backcount = s->nelements - 1;
      
      for (i = 0; i <= backcount; i++)
	{
	  sRef key = s->keys[i];
	  
	  if (sRef_lexLevel (key) > lexlevel)
	    {
	      int j;
	      for (j = backcount; j > i; j--)
		{
		  backcount--;
		  s->nelements--;
		  s->nspace++;
		  
		  if (sRef_lexLevel (s->keys[j]) <= lexlevel)
		    {
		      s->keys[i] = s->keys[j];
		      s->values[i] = s->values[j];
		      sRefSet_levelPrune (s->values[i], lexlevel);
		      /*@innerbreak@*/ break;
		    }
		}
	      if (backcount == i)
		s->nelements--;
	    }
	  else
	    {
	      sRefSet_levelPrune (s->values[i], lexlevel);
	    }
	}
    }
}

/*
** levelUnionSeq
**
**    like level union, but know that t2 was executed after t1.  So if
**    t1 has x -> { a, b } and t2 has x -> { a }, then result has x -> { a }.
**
** NOTE: t2 is "only".
*/

aliasTable aliasTable_levelUnionSeq (/*@returned@*/ aliasTable t1, 
				     /*@only@*/ aliasTable t2, int level)
{
  if (aliasTable_isUndefined (t2))
    {
      return t1;
    }

  if (aliasTable_isUndefined (t1))
    {
      t1 = aliasTable_newEmpty ();
    }
  else
    {
      aliasTable_levelPrune (t1, level);
    }

  aliasTable_elements (t2, key, value)
    {
      if (sRef_lexLevel (key) <= level)
	{
	  int ind = aliasTable_lookupRefs (t1, key);

	  sRefSet_levelPrune (value, level);
	      
	  if (ind == ATINVALID)
	    {
	      /* okay, t2 is killed */
	      /*@-exposetrans@*/ /*@-dependenttrans@*/ 
	      t1 = aliasTable_addSet (t1, key, value);
	      /*@=exposetrans@*/ /*@=dependenttrans@*/ 
	    }
	  else
	    {
	      sRefSet_free (t1->values[ind]);

	      /*@-dependenttrans@*/ /* okay, t2 is killed */
	      t1->values[ind] = value;
	      /*@=dependenttrans@*/
	    } 
	}
      else
	{
	  /*@-exposetrans@*/ /*@-dependenttrans@*/ 
	  sRefSet_free (value);
	  /*@=exposetrans@*/ /*@=dependenttrans@*/ 
	}

    } end_aliasTable_elements;
  
  sfree (t2->keys);
  sfree (t2->values);
  sfree (t2);

    return t1;
}

aliasTable 
aliasTable_levelUnion (/*@returned@*/ aliasTable t1, aliasTable t2, int level)
{
  if (aliasTable_isUndefined (t1))
    {
      if (aliasTable_isUndefined (t2)) 
	{
	  return t1;
	}
      else
	{
	  t1 = aliasTable_newEmpty ();
	}
    }
  else
    {
      aliasTable_levelPrune (t1, level);
    }

  aliasTable_elements (t2, key, cvalue)
    {
      sRefSet value = sRefSet_newCopy (cvalue);

      if (sRef_lexLevel (key) <= level)
	{
	  sRefSet_levelPrune (value, level);

	  if (sRefSet_size (value) > 0)
	    {
	      int ind = aliasTable_lookupRefs (t1, key);
	      
	      if (ind == ATINVALID)
		{
		  t1 = aliasTable_addSet (t1, key, value);
		}
	      else
		{
		  t1->values[ind] = sRefSet_union (t1->values[ind], value);
		  sRefSet_free (value);
		}
	    }
	  else
	    {
	      sRefSet_free (value); 
	    }
	}
      else
	{
	  sRefSet_free (value); 
	}
    } end_aliasTable_elements;

    return t1;
}

aliasTable aliasTable_levelUnionNew (aliasTable t1, aliasTable t2, int level)
{
  aliasTable ret = aliasTable_levelUnion (aliasTable_copy (t1), t2, level);

  return ret;
}

/*@only@*/ cstring
aliasTable_unparse (aliasTable s)
{
   cstring st = cstring_undefined;

   if (aliasTable_isUndefined (s)) return (cstring_makeLiteral ("<NULL>"));

   aliasTable_elements (s, key, value)
     {
       st = message ("%q\t%q -> %q\n", st, sRef_unparseFull (key), 
		     sRefSet_unparseFull (value));
     } end_aliasTable_elements;

   return st;
}

/*
** bogus!
*/

void
aliasTable_fixSrefs (aliasTable s)
{
  int i;

  if (aliasTable_isUndefined (s)) return;

  for (i = 0; i < s->nelements; i++)
    {
      sRef old = s->keys[i];

      if (sRef_isLocalVar (old))
	{
	  s->keys[i] = uentry_getSref (sRef_getUentry (old));
	}

      sRefSet_fixSrefs (s->values[i]);
    }
}

void
aliasTable_free (/*@only@*/ aliasTable s)
{
  int i;
  
  if (aliasTable_isUndefined (s)) return;
  
  for (i = 0; i < s->nelements; i++)
    {
      sRefSet_free (s->values[i]); 
    }
  
  sfree (s->values);
  sfree (s->keys);
  sfree (s);
}

void 
aliasTable_checkGlobs (aliasTable t)
{
  aliasTable_elements (t, key, value)
    {
      sRef root = sRef_getRootBase (key);

      if (sRef_isAliasCheckedGlobal (root))
	{
	  sRefSet_realElements (value, sr)
	    {
	      root = sRef_getRootBase (sr);

	      if (((sRef_isAliasCheckedGlobal (root) 
		    && !(sRef_similar (root, key)))
		   || sRef_isAnyParam (root))
		  && !sRef_isExposed (root))
		{
		  if (sRef_isAliasCheckedGlobal (key))
		    {
		      if (!(sRef_isShared (key) 
			    && sRef_isShared (root)))
			{
			  voptgenerror 
			    (FLG_GLOBALIAS,
			     message 
			     ("Function returns with %q variable %q aliasing %q %q",
			      cstring_makeLiteral (sRef_isRealGlobal (key) 
						   ? "global" : "file static"),
			      sRef_unparse (key),
			      cstring_makeLiteral (sRef_isAnyParam (root) 
						   ? "parameter" : "global"),
			      sRef_unparse (sr)),
			     g_currentloc);
			}
		    }

		}
	    } end_sRefSet_realElements;
	}
      else if (sRef_isAnyParam (key) || sRef_isAnyParam (root))
	{
	  sRefSet_realElements (value, sr)
	    {
	      root = sRef_getRootBase (sr);
	      
	      if (sRef_isAliasCheckedGlobal (root) 
		  && !sRef_isExposed (root)
		  && !sRef_isDead (key)
		  && !sRef_isShared (root))
		{
		  voptgenerror 
		    (FLG_GLOBALIAS,
		     message ("Function returns with parameter %q aliasing %q %q",
			      sRef_unparse (key),
			      cstring_makeLiteral (sRef_isRealGlobal (root) 
						   ? "global" : "file static"),
			      sRef_unparse (sr)),
		     g_currentloc);
		}
	    } end_sRefSet_realElements;
	}
      else
	{
	  ;
	}
    } end_aliasTable_elements;
}

# ifdef DEBUGSPLINT

/*
** For debugging only
*/

void aliasTable_checkValid (aliasTable t)
{
  aliasTable_elements (t, key, value)
    {
      sRef_checkCompletelyReasonable (key);

      sRefSet_elements (value, sr) 
	{
	  sRef_checkCompletelyReasonable (sr);
	} end_sRefSet_elements ;
    } end_aliasTable_elements ;
}
# endif
Commit	Line	Data
616915dd	1	/*
11db3170	2	** Splint - annotation-assisted static program checker
c59f5181	3	** Copyright (C) 1994-2003 University of Virginia,
616915dd	4	** Massachusetts Institute of Technology
	5	**
	6	** This program is free software; you can redistribute it and/or modify it
	7	** under the terms of the GNU General Public License as published by the
	8	** Free Software Foundation; either version 2 of the License, or (at your
	9	** option) any later version.
	10	**
	11	** This program is distributed in the hope that it will be useful, but
	12	** WITHOUT ANY WARRANTY; without even the implied warranty of
	13	** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	14	** General Public License for more details.
	15	**
	16	** The GNU General Public License is available from http://www.gnu.org/ or
	17	** the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
	18	** MA 02111-1307, USA.
	19	**
155af98d	20	** For information on splint: info@splint.org
155af98d	21	** To report a bug: splint-bug@splint.org
11db3170	22	** For more information: http://www.splint.org
616915dd	23	*/
	24	/*
	25	** aliasTable.c
	26	*/
	27
1b8ae690	28	# include "splintMacros.nf"
616915dd	29	# include "basic.h"
	30
	31	/@constant int ATINVALID; @/
	32	# define ATINVALID -1
	33
	34	static sRefSet
	35	aliasTable_canAliasAux (aliasTable p_s, sRef p_sr, int p_lim) /@/ ;
	36	static sRefSet
	37	aliasTable_aliasedByLimit (aliasTable p_s, sRef p_sr, int p_lim) /@/ ;
	38	static sRefSet
	39	aliasTable_aliasedByAux (aliasTable p_s, sRef p_sr, int p_lim) /@/ ;
	40
	41	aliasTable
	42	aliasTable_new ()
	43	{
	44	return (aliasTable_undefined);
	45	}
	46
	47	static /@only@/ /@notnull@/ aliasTable
	48	aliasTable_newEmpty (void)
	49	{
	50	aliasTable s = (aliasTable) dmalloc (sizeof (*s));
	51
	52	s->nelements = 0;
	53	s->nspace = aliasTableBASESIZE;
	54	s->keys = (sRef ) dmalloc (sizeof (s->keys) * aliasTableBASESIZE);
	55	s->values = (sRefSet ) dmalloc (sizeof (s->values) * aliasTableBASESIZE);
	56
	57	return (s);
	58	}
	59
	60	static void
	61	aliasTable_grow (/@notnull@/ aliasTable s)
	62	{
	63	int i;
	64	o_sRefSet *oldvalues = s->values;
	65	sRef *oldkeys = s->keys;
	66
	67	s->nspace += aliasTableBASESIZE;
	68
	69	s->values = (sRefSet ) dmalloc (sizeof (s->values)
	70	* (s->nelements + s->nspace));
	71	s->keys = (sRef ) dmalloc (sizeof (s->keys) * (s->nelements + aliasTableBASESIZE));
	72
	73	if (s->keys == (sRef ) 0 \|\| s->values == (sRefSet )0)
	74	{
	75	llfatalerror (cstring_makeLiteral ("aliasTable_grow: out of memory!"));
	76	}
	77
	78	for (i = 0; i < s->nelements; i++)
	79	{
	80	s->values[i] = oldvalues[i];
	81	s->keys[i] = oldkeys[i];
	82	}
	83
	84	sfree (oldvalues);
	85	sfree (oldkeys);
	86	}
	87
	88	static int aliasTable_lookupRefs (/@notnull@/ aliasTable s, sRef sr)
	89	{
	90	int i;
	91
	92
93	for (i = 0; i < aliasTable_size (s); i++)
94	{
95	if (sRef_same (sr, s->keys[i]))
96	{
97	return i;
98	}
99	}
100
101	return ATINVALID;
102	}
103
104	/*
105	** sr aliases al (and anything al aliases!)
106	*/
107
108	aliasTable
109	aliasTable_addMustAlias (/@returned@/ aliasTable s,
110	/@exposed@/ sRef sr,
28bf4b0b	111	/@exposed@/ sRef al)
616915dd	112	{
	113	int ind;
	114	sRefSet ss;
	115
	116	llassert (NOALIAS (sr, al));
28bf4b0b	117
	118	DPRINTF (("Adding alias: %s / %s", sRef_unparseFull (sr),
	119	sRef_unparseFull (al)));
616915dd	120
	121	if (aliasTable_isUndefined (s))
	122	{
	123	s = aliasTable_newEmpty ();
	124	ind = ATINVALID;
	125	}
	126	else
	127	{
	128	ind = aliasTable_lookupRefs (s, sr);
	129	}
	130
	131	ss = aliasTable_canAlias (s, al);
28bf4b0b	132	DPRINTF (("Previous aliases: %s", sRefSet_unparse (ss)));
616915dd	133
	134	if (ind == ATINVALID)
	135	{
	136	if (s->nspace <= 0) {
	137	aliasTable_grow (s);
	138	}
	139
	140	s->nspace--;
	141	s->keys[s->nelements] = sr;
	142	s->values[s->nelements] = sRefSet_single (al);
	143	ind = s->nelements;
	144	s->nelements++;
	145	}
	146	else
	147	{
	148	s->values[ind] = sRefSet_insert (s->values[ind], al);
	149	}
	150
	151	s->values[ind] = sRefSet_unionExcept (s->values[ind], ss, s->keys[ind]);
28bf4b0b	152	DPRINTF (("New aliases: %s", sRefSet_unparse (s->values[ind])));
616915dd	153
	154	sRefSet_free (ss);
	155	return s;
	156	}
	157
	158	static aliasTable
	159	aliasTable_addSet (/@returned@/ aliasTable s,
	160	/@exposed@/ sRef key, /@only@/ sRefSet value)
	161	{
	162	if (!sRefSet_isEmpty (value))
	163	{
	164	if (aliasTable_isUndefined (s))
	165	{
	166	s = aliasTable_newEmpty ();
	167	}
	168	else
	169	{
	170	if (s->nspace <= 0)
	171	{
	172	aliasTable_grow (s);
	173	}
	174	}
	175
	176	s->nspace--;
	177	s->keys[s->nelements] = key;
	178	s->values[s->nelements] = value;
	179	s->nelements++;
	180	}
	181	else
	182	{
	183	sRefSet_free (value);
	184	}
	185
	186	return s;
	187	}
	188
	189	/*
	190	** When aliases are cleared:
	191	**
	192	** o remove all entries for sr
	193	** o replace all aliases for things which alias sr with sr's aliases
	194	**
	195	** Clear aliases for sr; if sr is a direct param reference, clear its aliases too.
	196	*/
	197
	198	static void aliasTable_clearAliasesAux (/@notnull@/ aliasTable p_s, sRef p_sr)
	199	/@modifies p_s@/ ;
	200
	201	void aliasTable_clearAliases (aliasTable s, sRef sr)
	202	{
	203	if (aliasTable_isUndefined (s))
	204	{
	205	return;
	206	}
	207	else
	208	{
	209	sRef rb = sRef_getRootBase (sr);
	210
	211
	212	if (!sRef_isCvar (sr) && sRef_isLocalVar (rb))
	213	{
	214	int ind = aliasTable_lookupRefs (s, rb);
	215
	216	if (ind != ATINVALID)
217	{
218	sRefSet al = s->values[ind];
219
220
221	sRefSet_realElements (al, el)
222	{
223
224	if (sRef_isParam (el))
225	{
226	if (sRef_sameName (el, rb))
227	{
228	sRef fb = sRef_fixBase (sr, el);
229
230	aliasTable_clearAliasesAux (s, fb);
231	}
232	}
233	} end_sRefSet_realElements ;
234	}
235	}
236
237	aliasTable_clearAliasesAux (s, sr);
238	}
239	}
240
241	static
242	void aliasTable_clearAliasesAux (/@notnull@/ aliasTable s, sRef sr)
243	{
244	int i;
245
246	for (i = 0; i < s->nelements; i++)
247	{
248	sRef key = s->keys[i];
249
250	if (sRef_includedBy (key, sr))
251	{
252	sRefSet_clear (s->values[i]);
253	}
254	else
255	{
256	(void) sRefSet_deleteBase (s->values[i], sr);
257	}
258	}
259	}
260
261	/*
262	** returns set of all sRefs that must alias sr (but are different from sr)
263	*/
264
265	static /@only@/ sRefSet aliasTable_aliasedByAux (aliasTable s, sRef sr, int lim)
266	{
267	static bool hadWarning = FALSE;
268	sRefSet res = sRefSet_undefined;
269	int i;
270
271	llassert (!sRef_isConj (sr));
272
273
274	if (aliasTable_isUndefined (s) \|\| lim >= ALIASSEARCHLIMIT)
275	{
276	if (lim >= ALIASSEARCHLIMIT && !hadWarning)
277	{
278	llquietbug
279	(message ("Alias search limit exceeded, checking %q. "
280	"This either means there is a variable with at least "
11db3170	281	"%d indirections, or there is a bug in Splint.",
616915dd	282	sRef_unparse (sr),
	283	ALIASSEARCHLIMIT));
	284
	285	hadWarning = TRUE;
	286	}
	287
	288	return sRefSet_undefined;
	289	}
	290	else
	291	{
	292	sRefSet abl;
	293
	294	if (sRef_isPointer (sr))
	295	{
	296	abl = aliasTable_aliasedByLimit (s, sRef_getBase (sr), lim);
	297	res = sRefSet_addIndirection (abl);
	298	}
	299	else if (sRef_isAddress (sr))
	300	{
	301	abl = aliasTable_aliasedByLimit (s, sRef_getBase (sr), lim);
	302	res = sRefSet_removeIndirection (abl);
	303	}
	304	else if (sRef_isField (sr))
	305	{
	306	abl = aliasTable_aliasedByLimit (s, sRef_getBase (sr), lim);
	307	res = sRefSet_accessField (abl, sRef_getField (sr));
	308	}
	309	else if (sRef_isArrayFetch (sr))
	310	{
	311	abl = aliasTable_aliasedByLimit (s, sRef_getBase (sr), lim);
	312
	313	if (sRef_isIndexKnown (sr))
	314	{
	315	int idx = sRef_getIndex (sr);
	316
	317	res = sRefSet_fetchKnown (abl, idx);
	318	}
	319	else
	320	{
	321	res = sRefSet_fetchUnknown (abl);
	322	}
	323	}
	324	else
	325	{
	326	abl = sRefSet_undefined;
	327	}
	328
	329	sRefSet_free (abl);
	330	}
	331
	332	for (i = 0; i < s->nelements; i++)
	333	{
	334	sRef elem = s->keys[i];
	335
	336	if (!sRef_same (sr, elem)) /* was sameName */
	337	{
	338
	339	sRefSet_realElements (s->values[i], current)
	340	{
	341
	342	if (sRef_similar (sr, current))
	343	{
	344	res = sRefSet_insert (res, sRef_fixOuterRef (elem));
	345	/@innerbreak@/ break;
346	}
347	} end_sRefSet_realElements;
348	}
349	}
350
351	return res;
352	}
353
354	static /@only@/ sRefSet aliasTable_aliasedByLimit (aliasTable s, sRef sr, int lim)
355	{
356	sRefSet res;
357
358
359	if (sRef_isConj (sr))
360	{
361	res = sRefSet_unionFree (aliasTable_aliasedByLimit (s, sRef_getConjA (sr), lim),
362	aliasTable_aliasedByLimit (s, sRef_getConjB (sr), lim));
363	}
364	else
365	{
366	res = aliasTable_aliasedByAux (s, sr, lim + 1);
367	}
368
369	return res;
370	}
371
372	/@only@/ sRefSet aliasTable_aliasedBy (aliasTable s, sRef sr)
373	{
374	if (sRef_isConj (sr))
375	{
376	return (sRefSet_unionFree (aliasTable_aliasedBy (s, sRef_getConjA (sr)),
377	aliasTable_aliasedBy (s, sRef_getConjB (sr))));
378	}
379
380	return (aliasTable_aliasedByAux (s, sr, 0));
381	}
382
383	/@only@/ sRefSet aliasTable_canAlias (aliasTable s, sRef sr)
384	{
385	sRefSet res;
386
387
388	if (sRef_isConj (sr))
389	{
390	res = sRefSet_unionFree (aliasTable_canAlias (s, sRef_getConjA (sr)),
391	aliasTable_canAlias (s, sRef_getConjB (sr)));
392	}
393	else
394	{
395	res = aliasTable_canAliasAux (s, sr, 0);
396	}
397
398	return res;
399	}
400
401	/*
402	** need to limit the depth of aliasing searches
403	*/
404
405	static /@only@/ sRefSet aliasTable_canAliasLimit (aliasTable s, sRef sr, int lim)
406	{
407	sRefSet res;
408
409	if (sRef_isConj (sr))
410	{
411	sRefSet a = aliasTable_canAliasLimit (s, sRef_getConjA (sr), lim);
412	sRefSet b = aliasTable_canAliasLimit (s, sRef_getConjB (sr), lim);
413
414	res = sRefSet_unionFree (a, b);
415	}
416	else
417	{
418	res = aliasTable_canAliasAux (s, sr, lim + 1);
419	}
420
421	return res;
422	}
423
424	static /@only@/ sRefSet
425	aliasTable_canAliasAux (aliasTable s, sRef sr, int lim)
426	{
427	static bool hadWarning = FALSE;
428	llassert (!sRef_isConj (sr));
429
430
431	if (aliasTable_isUndefined (s) \|\| lim >= ALIASSEARCHLIMIT)
432	{
433	if (lim >= ALIASSEARCHLIMIT && !hadWarning)
434	{
435	llquietbug
436	(message ("Alias search limit exceeded, checking %q. "
437	"This either means there is a variable with at least "
11db3170	438	"%d indirections, or there is a bug in Splint.",
616915dd	439	sRef_unparse (sr),
	440	ALIASSEARCHLIMIT));
	441
	442	hadWarning = TRUE;
	443	}
	444
	445	return sRefSet_undefined;
	446	}
	447	else
	448	{
	449	int ind = aliasTable_lookupRefs (s, sr);
	450
	451	if (sRef_isPointer (sr) \|\| sRef_isAddress (sr) \|\| sRef_isField (sr)
	452	\|\| sRef_isArrayFetch (sr))
	453	{
	454	sRef base = sRef_getBase (sr);
	455	sRefSet tmp = aliasTable_canAliasLimit (s, base, lim);
	456	sRefSet ret;
	457
	458	if (sRef_isPointer (sr))
	459	{
	460	ret = sRefSet_addIndirection (tmp);
	461	}
	462	else if (sRef_isAddress (sr))
	463	{
	464	ret = sRefSet_removeIndirection (tmp);
	465	}
	466	else if (sRef_isField (sr))
	467	{
	468	ret = sRefSet_accessField (tmp, sRef_getField (sr));
	469	}
	470	else if (sRef_isArrayFetch (sr))
	471	{
	472	if (sRef_isIndexKnown (sr))
	473	{
	474	ret = sRefSet_fetchKnown (tmp, sRef_getIndex (sr));
	475	}
	476	else
	477	{
	478	ret = sRefSet_fetchUnknown (tmp);
	479	}
	480	}
	481	else
	482	{
	483	BADBRANCH;
	484	}
	485
	486	if (ind != ATINVALID)
	487	{
	488	ret = sRefSet_union (ret, s->values[ind]);
	489	}
28bf4b0b	490
616915dd	491	sRefSet_free (tmp);
28bf4b0b	492	return ret;
616915dd	493	}
	494
	495	if (ind == ATINVALID) return sRefSet_undefined;
	496
	497	return sRefSet_newCopy (s->values[ind]);
	498	}
	499	}
	500
	501	aliasTable aliasTable_copy (aliasTable s)
	502	{
	503	if (aliasTable_isEmpty (s))
	504	{
	505	return aliasTable_undefined;
	506	}
	507	else
	508	{
	509	aliasTable t = (aliasTable) dmalloc (sizeof (*s));
	510	int i;
	511
	512	t->nelements = s->nelements;
	513	t->nspace = 0;
	514	t->keys = (sRef ) dmalloc (sizeof (s->keys) * s->nelements);
	515	t->values = (sRefSet ) dmalloc (sizeof (s->values) * t->nelements);
	516
	517	for (i = 0; i < s->nelements; i++)
	518	{
	519	t->keys[i] = s->keys[i];
	520	t->values[i] = sRefSet_newCopy (s->values[i]);
	521	}
	522
	523	return t;
	524	}
	525	}
	526
	527	static void
	528	aliasTable_levelPrune (aliasTable s, int lexlevel)
	529	{
	530
	531
	532	if (aliasTable_isEmpty (s))
	533	{
	534	return;
	535	}
	536	else
	537	{
	538	int i;
	539	int backcount = s->nelements - 1;
	540
	541	for (i = 0; i <= backcount; i++)
	542	{
	543	sRef key = s->keys[i];
	544
	545	if (sRef_lexLevel (key) > lexlevel)
	546	{
	547	int j;
	548	for (j = backcount; j > i; j--)
	549	{
	550	backcount--;
	551	s->nelements--;
	552	s->nspace++;
	553
	554	if (sRef_lexLevel (s->keys[j]) <= lexlevel)
	555	{
	556	s->keys[i] = s->keys[j];
557	s->values[i] = s->values[j];
558	sRefSet_levelPrune (s->values[i], lexlevel);
559	/@innerbreak@/ break;
560	}
561	}
562	if (backcount == i)
563	s->nelements--;
564	}
565	else
566	{
567	sRefSet_levelPrune (s->values[i], lexlevel);
568	}
569	}
570	}
571	}
572
573	/*
574	** levelUnionSeq
575	**
576	** like level union, but know that t2 was executed after t1. So if
577	** t1 has x -> { a, b } and t2 has x -> { a }, then result has x -> { a }.
578	**
579	** NOTE: t2 is "only".
580	*/
581
582	aliasTable aliasTable_levelUnionSeq (/@returned@/ aliasTable t1,
583	/@only@/ aliasTable t2, int level)
584	{
585	if (aliasTable_isUndefined (t2))
586	{
587	return t1;
588	}
589
590	if (aliasTable_isUndefined (t1))
591	{
592	t1 = aliasTable_newEmpty ();
593	}
594	else
595	{
596	aliasTable_levelPrune (t1, level);
597	}
598
599	aliasTable_elements (t2, key, value)
600	{
601	if (sRef_lexLevel (key) <= level)
602	{
603	int ind = aliasTable_lookupRefs (t1, key);
604
605	sRefSet_levelPrune (value, level);
606
607	if (ind == ATINVALID)
608	{
609	/* okay, t2 is killed */
610	/@-exposetrans@/ /@-dependenttrans@/
611	t1 = aliasTable_addSet (t1, key, value);
612	/@=exposetrans@/ /@=dependenttrans@/
613	}
614	else
615	{
616	sRefSet_free (t1->values[ind]);
617
618	/@-dependenttrans@/ /* okay, t2 is killed */
619	t1->values[ind] = value;
620	/@=dependenttrans@/
621	}
622	}
623	else
624	{
625	/@-exposetrans@/ /@-dependenttrans@/
626	sRefSet_free (value);
627	/@=exposetrans@/ /@=dependenttrans@/
628	}
629
630	} end_aliasTable_elements;
631
632	sfree (t2->keys);
633	sfree (t2->values);
634	sfree (t2);
635
636	return t1;
637	}
638
639	aliasTable
640	aliasTable_levelUnion (/@returned@/ aliasTable t1, aliasTable t2, int level)
641	{
642	if (aliasTable_isUndefined (t1))
643	{
644	if (aliasTable_isUndefined (t2))
645	{
646	return t1;
647	}
648	else
649	{
650	t1 = aliasTable_newEmpty ();
651	}
652	}
653	else
654	{
655	aliasTable_levelPrune (t1, level);
656	}
657
658	aliasTable_elements (t2, key, cvalue)
659	{
660	sRefSet value = sRefSet_newCopy (cvalue);
661
662	if (sRef_lexLevel (key) <= level)
663	{
664	sRefSet_levelPrune (value, level);
665
666	if (sRefSet_size (value) > 0)
667	{
668	int ind = aliasTable_lookupRefs (t1, key);
669
670	if (ind == ATINVALID)
671	{
672	t1 = aliasTable_addSet (t1, key, value);
673	}
674	else
675	{
676	t1->values[ind] = sRefSet_union (t1->values[ind], value);
677	sRefSet_free (value);
678	}
679	}
680	else
681	{
682	sRefSet_free (value);
683	}
684	}
685	else
686	{
687	sRefSet_free (value);
688	}
689	} end_aliasTable_elements;
690
691	return t1;
692	}
693
694	aliasTable aliasTable_levelUnionNew (aliasTable t1, aliasTable t2, int level)
695	{
696	aliasTable ret = aliasTable_levelUnion (aliasTable_copy (t1), t2, level);
697
698	return ret;
699	}
700
701	/@only@/ cstring
702	aliasTable_unparse (aliasTable s)
703	{
704	cstring st = cstring_undefined;
705
706	if (aliasTable_isUndefined (s)) return (cstring_makeLiteral ("<NULL>"));
707
708	aliasTable_elements (s, key, value)
709	{
28bf4b0b	710	st = message ("%q\t%q -> %q\n", st, sRef_unparseFull (key),
28bf4b0b	711	sRefSet_unparseFull (value));
616915dd	712	} end_aliasTable_elements;
	713
	714	return st;
	715	}
	716
	717	/*
	718	** bogus!
	719	*/
	720
	721	void
	722	aliasTable_fixSrefs (aliasTable s)
	723	{
	724	int i;
	725
	726	if (aliasTable_isUndefined (s)) return;
	727
	728	for (i = 0; i < s->nelements; i++)
	729	{
	730	sRef old = s->keys[i];
	731
	732	if (sRef_isLocalVar (old))
	733	{
	734	s->keys[i] = uentry_getSref (sRef_getUentry (old));
	735	}
	736
	737	sRefSet_fixSrefs (s->values[i]);
	738	}
	739	}
	740
	741	void
	742	aliasTable_free (/@only@/ aliasTable s)
	743	{
	744	int i;
	745
	746	if (aliasTable_isUndefined (s)) return;
	747
	748	for (i = 0; i < s->nelements; i++)
	749	{
	750	sRefSet_free (s->values[i]);
	751	}
	752
	753	sfree (s->values);
	754	sfree (s->keys);
	755	sfree (s);
	756	}
	757
	758	void
	759	aliasTable_checkGlobs (aliasTable t)
	760	{
	761	aliasTable_elements (t, key, value)
	762	{
	763	sRef root = sRef_getRootBase (key);
	764
	765	if (sRef_isAliasCheckedGlobal (root))
	766	{
	767	sRefSet_realElements (value, sr)
	768	{
	769	root = sRef_getRootBase (sr);
	770
	771	if (((sRef_isAliasCheckedGlobal (root)
	772	&& !(sRef_similar (root, key)))
	773	\|\| sRef_isAnyParam (root))
	774	&& !sRef_isExposed (root))
	775	{
776	if (sRef_isAliasCheckedGlobal (key))
777	{
778	if (!(sRef_isShared (key)
779	&& sRef_isShared (root)))
780	{
781	voptgenerror
782	(FLG_GLOBALIAS,
783	message
784	("Function returns with %q variable %q aliasing %q %q",
785	cstring_makeLiteral (sRef_isRealGlobal (key)
786	? "global" : "file static"),
787	sRef_unparse (key),
788	cstring_makeLiteral (sRef_isAnyParam (root)
789	? "parameter" : "global"),
790	sRef_unparse (sr)),
791	g_currentloc);
792	}
793	}
794
795	}
796	} end_sRefSet_realElements;
797	}
798	else if (sRef_isAnyParam (key) \|\| sRef_isAnyParam (root))
799	{
800	sRefSet_realElements (value, sr)
801	{
802	root = sRef_getRootBase (sr);
803
804	if (sRef_isAliasCheckedGlobal (root)
805	&& !sRef_isExposed (root)
806	&& !sRef_isDead (key)
807	&& !sRef_isShared (root))
808	{
809	voptgenerror
810	(FLG_GLOBALIAS,
811	message ("Function returns with parameter %q aliasing %q %q",
812	sRef_unparse (key),
813	cstring_makeLiteral (sRef_isRealGlobal (root)
814	? "global" : "file static"),
815	sRef_unparse (sr)),
816	g_currentloc);
817	}
818	} end_sRefSet_realElements;
819	}
820	else
821	{
822	;
823	}
824	} end_aliasTable_elements;
825	}
826
6483a926	827	# ifdef DEBUGSPLINT
616915dd	828
6483a926	829	/*
	830	** For debugging only
	831	*/
	832
	833	void aliasTable_checkValid (aliasTable t)
	834	{
	835	aliasTable_elements (t, key, value)
	836	{
02b84d4b	837	sRef_checkCompletelyReasonable (key);
616915dd	838
6483a926	839	sRefSet_elements (value, sr)
6483a926	840	{
02b84d4b	841	sRef_checkCompletelyReasonable (sr);
6483a926	842	} end_sRefSet_elements ;
	843	} end_aliasTable_elements ;
	844	}
	845	# endif