[Patch] Warning during GCC bootstrap on i686-pc-mingw32

[Kai Tietz]

"Danny Smith" <dansmister@gmail.com> wrote on 16.04.2008 03:52:18:

> As noted in
> http://gcc.gnu.org/ml/gcc/2008-04/msg00371.html
> 
> the pedantic warning for the use of "I64" printf length specifier
> "../../src/gcc/cfg.c:540: warning: ISO C does not support the ''
> ms_printf length modifier"
> is wrong.
> 
> The problem is in the use of '\0' as a prefix to flag multichar length
> specs string.
> 
> This patch gets rid of the use of a terminator as a prefix and simply
> uses strncmp to handle
> the comparison .
> 
> Tested i686-pc-mingw32.
> 
> OK for trunk?
> 
> 2008-04-16  Danny Smith  <dannysmith@users.net>
> 
>    * c-format.c (check_format_info_main): Use strncmp rather than a 
> magic prefix
>    to handle multichar length specs.
>    * config/i386/msformat-c.c (format_length_info 
ms_printf_length_specs):
>    Don't prefix "I64" and "I32" with '\0'.
> 
> Index: c-format.c
> ===================================================================
> --- c-format.c   (revision 134294)
> +++ c-format.c   (working copy)
> @@ -1779,26 +1779,12 @@
>        length_chars_std = STD_C89;
>        if (fli)
>     {
> -     while (fli->name != 0 && fli->name[0] != *format_chars)
> -       {
> -         if (fli->name[0] == '\0')
> -      {
> -        int si  = strlen (fli->name + 1) + 1;
> -        int i = 1;
> -        while (fli->name[i] != 0 && fli->name[i] == format_chars [i - 
1])
> -          ++i;
> -       if (si == i)
> -         {
> -           if (si > 2)
> -             format_chars += si - 2;
> -           break;
> -         }
> -          }
> +     while (fli->name != 0
> +        && strncmp (fli->name, format_chars, strlen (fli->name)))
>           fli++;
> -       }
>       if (fli->name != 0)
>         {
> -         format_chars++;
> +          format_chars += strlen (fli->name);
>           if (fli->double_name != 0 && fli->name[0] == *format_chars)
>        {
>          format_chars++;
> Index: config/i386/msformat-c.c
> ===================================================================
> --- config/i386/msformat-c.c   (revision 134294)
> +++ config/i386/msformat-c.c   (working copy)
> @@ -38,8 +38,8 @@
>  {
>    { "h", FMT_LEN_h, STD_C89, NULL, 0, 0 },
>    { "l", FMT_LEN_l, STD_C89, NULL, 0, 0 },
> -  { "\0I32", FMT_LEN_l, STD_EXT, NULL, 0, 0 },
> -  { "\0I64", FMT_LEN_ll, STD_EXT, NULL, 0, 0 },
> +  { "I32", FMT_LEN_l, STD_EXT, NULL, 0, 0 },
> +  { "I64", FMT_LEN_ll, STD_EXT, NULL, 0, 0 },
>    { "I", FMT_[PatchLEN_L, STD_EXT, NULL, 0, 0 },
>    { NULL, 0, 0, NULL, 0, 0 }
>  };
> 

AFAICS does this patch won't work. Because it breaks as example "l"/"ll" 
checking in default case (gnu_printf). I think it is better to use a macro 
on output for ->name. Something like this:

#define MAY_LEADZERO(NAME)      ((NAME) + (((NAME)[0])==0 ? 1 : 0)

Cheers,
  Kai

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