[PING][PATCH] Include safe-ctype.h after C++ standard headers, to avoid over-poisoning

[Dimitry Andric <dimitry@andric.com>]

Ping. It would be nice to get this QoL fix in.

-Dimitry

> On 28 Sep 2023, at 18:37, Dimitry Andric <dimitry@andric.com> wrote:
> 
> Ref: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111632
> 
> When building gcc's C++ sources against recent libc++, the poisoning of
> the ctype macros due to including safe-ctype.h before including C++
> standard headers such as <list>, <map>, etc, causes many compilation
> errors, similar to:
> 
> In file included from /home/dim/src/gcc/master/gcc/gensupport.cc:23:
> In file included from /home/dim/src/gcc/master/gcc/system.h:233:
> In file included from /usr/include/c++/v1/vector:321:
> In file included from
> /usr/include/c++/v1/__format/formatter_bool.h:20:
> In file included from
> /usr/include/c++/v1/__format/formatter_integral.h:32:
> In file included from /usr/include/c++/v1/locale:202:
> /usr/include/c++/v1/__locale:546:5: error: '__abi_tag__' attribute
> only applies to structs, variables, functions, and namespaces
>   546 |     _LIBCPP_INLINE_VISIBILITY
>       |     ^
> /usr/include/c++/v1/__config:813:37: note: expanded from macro
> '_LIBCPP_INLINE_VISIBILITY'
>   813 | #  define _LIBCPP_INLINE_VISIBILITY _LIBCPP_HIDE_FROM_ABI
>       |                                     ^
> /usr/include/c++/v1/__config:792:26: note: expanded from macro
> '_LIBCPP_HIDE_FROM_ABI'
>   792 |
>   __attribute__((__abi_tag__(_LIBCPP_TOSTRING(
> _LIBCPP_VERSIONED_IDENTIFIER))))
>       |                          ^
> In file included from /home/dim/src/gcc/master/gcc/gensupport.cc:23:
> In file included from /home/dim/src/gcc/master/gcc/system.h:233:
> In file included from /usr/include/c++/v1/vector:321:
> In file included from
> /usr/include/c++/v1/__format/formatter_bool.h:20:
> In file included from
> /usr/include/c++/v1/__format/formatter_integral.h:32:
> In file included from /usr/include/c++/v1/locale:202:
> /usr/include/c++/v1/__locale:547:37: error: expected ';' at end of
> declaration list
>   547 |     char_type toupper(char_type __c) const
>       |                                     ^
> /usr/include/c++/v1/__locale:553:48: error: too many arguments
> provided to function-like macro invocation
>   553 |     const char_type* toupper(char_type* __low, const
>   char_type* __high) const
>       |                                                ^
> /home/dim/src/gcc/master/gcc/../include/safe-ctype.h:146:9: note:
> macro 'toupper' defined here
>   146 | #define toupper(c) do_not_use_toupper_with_safe_ctype
>       |         ^
> 
> This is because libc++ uses different transitive includes than
> libstdc++, and some of those transitive includes pull in various ctype
> declarations (typically via <locale>).
> 
> There was already a special case for including <string> before
> safe-ctype.h, so move the rest of the C++ standard header includes to
> the same location, to fix the problem.
> 
> Signed-off-by: Dimitry Andric <dimitry@andric.com>
> ---
> gcc/system.h | 39 ++++++++++++++++++---------------------
> 1 file changed, 18 insertions(+), 21 deletions(-)
> 
> diff --git a/gcc/system.h b/gcc/system.h
> index e924152ad4c..7a516b11438 100644
> --- a/gcc/system.h
> +++ b/gcc/system.h
> @@ -194,27 +194,8 @@ extern int fprintf_unlocked (FILE *, const char *, ...);
> #undef fread_unlocked
> #undef fwrite_unlocked
> 
> -/* Include <string> before "safe-ctype.h" to avoid GCC poisoning
> -   the ctype macros through safe-ctype.h */
> -
> -#ifdef __cplusplus
> -#ifdef INCLUDE_STRING
> -# include <string>
> -#endif
> -#endif
> -
> -/* There are an extraordinary number of issues with <ctype.h>.
> -   The last straw is that it varies with the locale.  Use libiberty's
> -   replacement instead.  */
> -#include "safe-ctype.h"
> -
> -#include <sys/types.h>
> -
> -#include <errno.h>
> -
> -#if !defined (errno) && defined (HAVE_DECL_ERRNO) && !HAVE_DECL_ERRNO
> -extern int errno;
> -#endif
> +/* Include C++ standard headers before "safe-ctype.h" to avoid GCC
> +   poisoning the ctype macros through safe-ctype.h */
> 
> #ifdef __cplusplus
> #if defined (INCLUDE_ALGORITHM) || !defined (HAVE_SWAP_IN_UTILITY)
> @@ -229,6 +210,9 @@ extern int errno;
> #ifdef INCLUDE_SET
> # include <set>
> #endif
> +#ifdef INCLUDE_STRING
> +# include <string>
> +#endif
> #ifdef INCLUDE_VECTOR
> # include <vector>
> #endif
> @@ -245,6 +229,19 @@ extern int errno;
> # include <type_traits>
> #endif
> 
> +/* There are an extraordinary number of issues with <ctype.h>.
> +   The last straw is that it varies with the locale.  Use libiberty's
> +   replacement instead.  */
> +#include "safe-ctype.h"
> +
> +#include <sys/types.h>
> +
> +#include <errno.h>
> +
> +#if !defined (errno) && defined (HAVE_DECL_ERRNO) && !HAVE_DECL_ERRNO
> +extern int errno;
> +#endif
> +
> /* Some of glibc's string inlines cause warnings.  Plus we'd rather
>   rely on (and therefore test) GCC's string builtins.  */
> #define __NO_STRING_INLINES
> -- 
> 2.42.0
>