On Thu, Apr 07, 2022 at 05:52:53PM +0200, Jakub Jelinek wrote:
> Hi!
>
> In the PR Joseph said that the C standard for va_arg talks about
> pointers to object type and as a function type is not object type,
> it is invalid.
>
> The following patch diagnoses it in the FE, instead of ICEing later on
> when optimizations are turned on (and with -O0 doing something weird
> at runtime).
>
> Bootstrapped/regtested on powerpc64le-linux, ok for trunk?
Ok, thanks.
> 2022-04-07 Jakub Jelinek <ja...@redhat.com>
>
> PR c/105149
> * c-typeck.cc (c_build_va_arg): Reject function types.
>
> * gcc.dg/pr105149.c: New test.
>
> --- gcc/c/c-typeck.cc.jj 2022-03-23 10:29:20.172967605 +0100
> +++ gcc/c/c-typeck.cc 2022-04-07 12:26:17.236469809 +0200
> @@ -15896,6 +15896,12 @@ c_build_va_arg (location_t loc1, tree ex
> "type %qT", type);
> return error_mark_node;
> }
> + else if (TREE_CODE (type) == FUNCTION_TYPE)
> + {
> + error_at (loc2, "second argument to %<va_arg%> is a function type %qT",
> + type);
> + return error_mark_node;
> + }
> else if (warn_cxx_compat && TREE_CODE (type) == ENUMERAL_TYPE)
> warning_at (loc2, OPT_Wc___compat,
> "C++ requires promoted type, not enum type, in %<va_arg%>");
> --- gcc/testsuite/gcc.dg/pr105149.c.jj 2022-04-07 12:39:08.202711511
> +0200
> +++ gcc/testsuite/gcc.dg/pr105149.c 2022-04-07 12:38:21.418364583 +0200
> @@ -0,0 +1,16 @@
> +/* PR c/105149 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2" } */
> +
> +#include <stdarg.h>
> +
> +void
> +foo (int s, ...)
> +{
> + int e;
> + va_list ap;
> +
> + va_start (ap, s);
> + e = va_arg (ap, int (void)) (); /* { dg-error "second argument to
> 'va_arg' is a function type" } */
> + va_end (ap);
> +}
Marek
