Re: [CIL users] CIL transformation results in GCC warning

[Matt H. <ma...@cs...>]

Moritz Jodeit wrote:

>Hi all,
>
>I ran across some code, which falsely generates a warning using CIL.
>The following code snippet demonstrates it:
>
>1	#include <stdio.h>
>2	#include <stdlib.h>
>3
>4	int main(void) {
>5		char *p;
>6		int i;
>7
>8		p = malloc(2*sizeof(int));
>9		*(int *)p       = 1;
>10		*((int *)p + 1) = 2;
>11
>12		i = *((int *)p)++;
>13		printf("%d\n", i);
>14		i = *((int *)p)++;
>15		printf("%d\n", i);
>16
>17		return 0;
>18	}
>
>Line 12 and 14 are transformed to:
>
>...
>#line 12
>  tmp = (int *)p;
>#line 12
>  p = (int *)p + 1;
>#line 12
>  i = *tmp;
>...
>
>GCC justifiably generates a warning for the "p = (int *)p + 1" construct.
>CIL should probably add the missing cast to (char *), so that it
>transforms to the following construct:
>
>	p = (char *)((int *)p + 1)
>
>What do you think?
>
>Moritz
>
Hi Moritz,

You are right.  Here is a patch:

Thanks,
Matt

--- src/frontc/cabs2cil.ml      (revision 8636)
+++ src/frontc/cabs2cil.ml      (working copy)
@@ -3621,7 +3621,7 @@
                  se, e'
              in
              finishExp
-               (se' +++ (Set(lv, makeCastT opresult tresult t,
+               (se' +++ (Set(lv, makeCastT opresult tresult (typeOfLval 
lv),
                              !currentLoc)))
                result
                tresult   (* Should this be t instead ??? *)