Re: Using Alias analysis

[Daniel Berlin <dberlin at dberlin dot org>]

On Fri, 2005-11-11 at 19:33 +0000, drizzle drizzle wrote:
> Hi .
>        I want to use gcc's alias analysis in a standalone way. What I
> observe is that a lot of the information is hidden because of
> additional temporaries that have been generated. Can any one suggest
> as to if there is a simple workaround to this ?
> 
>  To illustrate what I am saying
> 
>  for a stmt
>  heap_ptr= (int**) malloc the alias analysis tells me D.1072 points to
> malloc and heap_ptr points to anything

You shouldn't see this, and in fact, i don't.

#include <string.h>
int
main ()
{

int **fooptr;
fooptr = (int **)malloc (sizeof (int *));
  return 0;
}

gives

main ()
{
  intD.0 * * fooptrD.1403;
  intD.0 D.1405;
  voidD.28 * D.1404;

  # BLOCK 0
  # PRED: ENTRY (fallthru)
  #   HEAP.5D.1417_6 = V_MAY_DEF <HEAP.5D.1417_5>;
  D.1404_1 = malloc (4);
  fooptrD.1403_2 = (intD.0 * *) D.1404_1;
  D.1405_3 = 0;
  return D.1405_3;
  # SUCC: EXIT

}

D.1404_1 = { HEAP.5 }
HEAP.5 = { ANYTHING }
fooptr_2 = { HEAP.5 }


IE we say that fooptr_2 points to HEAP.




> .  I would have liked to see
> heap_ptr points to malloc.
> 

Uh, 
> 
>  Any way I can get that information.....
>  I would appreciate any idea/suggestions ...
>  dz