On 02/07/2018 06:53 PM, David Malcolm wrote:
> PR c/84258 reports that we issue this:
>
> warning: format is a wide character string [-Wformat=]
>
> on this code:
>
> const unsigned char cuc[] = "%i";
> sprintf(buf, (char *)cuc, 1);
>
> despite the absence of wide characters.
>
> This wording dates back 17.5 years to r36586:
>
> 2000-09-24 Joseph S. Myers <js...@cam.ac.uk>
>
> * c-common.c (check_format_info): Warn for a wide character string
> used as a non-wide format argument.
>
> * gcc.dg/c90-printf-1.c: Add test for wide string format.
>
> which handled this case:
>
> printf ((const char *)L"foo"); /* { dg-warning "wide" "wide string" } */
>
> The code in question is currently just checking for something that isn't
> char_type_node.
>
> digest_init converts the string literal to the type of the array, converting
> it from array of char to array of unsigned char, leading to the condition
> failing.
>
> This patch fixes the nonsensical message by checking for the other string
> types that lex_string can emit - char16_array_type_node,
> char32_array_type_node, and wchar_array_type_node - and only referring
> to "wide character string" if it's one of them. Otherwise it uses a new,
> more generic wording.
>
> Successfully bootstrapped®rtested on x86_64-pc-linux-gnu.
>
> This isn't a regression, but is fairly low risk.
>
> OK for trunk, either now, or for next stage 1?
>
> gcc/c-family/ChangeLog:
> PR c/84258
> * c-format.c (struct format_check_results): Add field
> "number_non_char".
> (check_format_info): Initialize it, and warn if encountered.
> (check_format_arg): Distinguish between wide char and
> everything else when detecting arrays of non-char.
>
> gcc/testsuite/ChangeLog:
> PR c/84258
> * c-c++-common/Wformat-pr84258.c: New test.
OK for the trunk.
Jeff
