On Sat, 9 Aug 2014, Marek Polacek wrote:
> + /* Maybe we want to issue the C90/C99 compat warning, which is more
> + specific than -pedantic. */
> + if (warn_c90_c99_compat > 0)
> {
> diagnostic_set_info (&diagnostic, gmsgid, &ap, location, DK_WARNING);
That seems wrong; it means that -Wc90-c99-compat turns errors from
-pedantic-errors into warnings. E.g.
const const int i;
with -std=c90 -pedantic-errors gets an error, but (with this patch
applied) with -Wc90-c99-compat it becomes a warning.
(In view of this problem I haven't reviewed the rest of this patch.)
> diff --git gcc/gcc/c/c-parser.c gcc/gcc/c/c-parser.c
> index ca8577c..454f279 100644
> --- gcc/gcc/c/c-parser.c
> +++ gcc/gcc/c/c-parser.c
> @@ -1073,7 +1073,10 @@ disable_extension_diagnostics (void)
> | (warn_long_long << 4)
> | (warn_cxx_compat << 5)
> | (warn_overlength_strings << 6)
> - | (warn_c90_c99_compat << 7));
> + /* warn_c90_c99_compat has three states: -1/0/1, so we must
> + play tricks to properly restore it. */
> + | (warn_c90_c99_compat << 7)
> + | ((warn_c90_c99_compat == -1) << 8));
This doesn't make sense to me either. You're left-shifting a negative
value (undefined behavior in ISO C, so should be avoided anyway), and left
shifting -1 means that all the bits to the left of bit 7 in the result
will also be set so can't be used to carry any other information (in
particular bit 8 will be set, so this code will in fact work, but by
accident).
--
Joseph S. Myers
jos...@codesourcery.com
