[PATCH] c-family: Fix ICE in get_atomic_generic_size [PR96545]

Marek Polacek polacek@redhat.com
Tue Aug 11 13:31:58 GMT 2020


On Tue, Aug 11, 2020 at 10:50:28AM +0200, Jakub Jelinek via Gcc-patches wrote:
> Hi!
> 
> As the testcase shows, we would ICE if the type of the first argument of
> various atomic builtins was pointer to (non-void) incomplete type, we would
> assume that TYPE_SIZE_UNIT must be non-NULL.  This patch diagnoses it
> instead.  And also changes the TREE_CODE != INTEGER_CST check to
> !tree_fits_uhwi_p, as we use tree_to_uhwi after this and at least in theory
> the int could be too large and not fit.
> 
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

OK.

> 2020-08-10  Jakub Jelinek  <jakub@redhat.com>
> 
> 	PR c/96545
> 	* c-common.c (get_atomic_generic_size): Require that first argument's
> 	type points to a complete type and use tree_fits_uhwi_p instead of
> 	just INTEGER_CST TREE_CODE check for the TYPE_SIZE_UNIT.
> 
> 	* c-c++-common/pr96545.c: New test.
> 
> --- gcc/c-family/c-common.c.jj	2020-07-31 23:07:00.566153515 +0200
> +++ gcc/c-family/c-common.c	2020-08-10 12:03:35.236841534 +0200
> @@ -7017,8 +7017,15 @@ get_atomic_generic_size (location_t loc,
>        return 0;
>      }
>  
> +  if (!COMPLETE_TYPE_P (TREE_TYPE (type_0)))
> +    {
> +      error_at (loc, "argument 1 of %qE must be a pointer to a complete type",
> +		function);
> +      return 0;
> +    }
> +
>    /* Types must be compile time constant sizes. */
> -  if (TREE_CODE ((TYPE_SIZE_UNIT (TREE_TYPE (type_0)))) != INTEGER_CST)
> +  if (!tree_fits_uhwi_p ((TYPE_SIZE_UNIT (TREE_TYPE (type_0)))))
>      {
>        error_at (loc, 
>  		"argument 1 of %qE must be a pointer to a constant size type",
> --- gcc/testsuite/c-c++-common/pr96545.c.jj	2020-08-10 12:28:43.296222401 +0200
> +++ gcc/testsuite/c-c++-common/pr96545.c	2020-08-10 12:28:28.258428487 +0200
> @@ -0,0 +1,31 @@
> +/* PR c/96545 */
> +/* { dg-do compile } */
> +
> +extern char x[], y[], z[];
> +struct S;
> +extern struct S s, t, u;
> +int v, w;
> +
> +void
> +foo (void)
> +{
> +  __atomic_exchange (&x, &y, &z, 0);	/* { dg-error "must be a pointer to a complete type" } */
> +}
> +
> +void
> +bar (void)
> +{
> +  __atomic_exchange (&s, &t, &u, 0);	/* { dg-error "must be a pointer to a complete type" } */
> +}
> +
> +void
> +baz (void)
> +{
> +  __atomic_exchange (&v, &t, &w, 0);	/* { dg-error "size mismatch in argument 2 of" } */
> +}
> +
> +void
> +qux (void)
> +{
> +  __atomic_exchange (&v, &w, &t, 0);	/* { dg-error "size mismatch in argument 3 of" } */
> +}
> 
> 	Jakub
> 

Marek



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