[gcc r11-11549] Include safe-ctype.h after C++ standard headers, to avoid over-poisoning

[Iain D Sandoe]

https://gcc.gnu.org/g:5a419c22e67b30bfa10a59351c64663396a4c8f2

commit r11-11549-g5a419c22e67b30bfa10a59351c64663396a4c8f2
Author: Francois-Xavier Coudert <fxcoudert@gcc.gnu.org>
Date:   Thu Mar 7 14:36:03 2024 +0100

    Include safe-ctype.h after C++ standard headers, to avoid over-poisoning
    
    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.
    
    gcc/ChangeLog:
    
            * system.h: Include safe-ctype.h after C++ standard headers.
    
    Signed-off-by: Dimitry Andric <dimitry@andric.com>
    (cherry picked from commit 9970b576b7e4ae337af1268395ff221348c4b34a)

Diff:
---
 gcc/system.h | 39 ++++++++++++++++++---------------------
 1 file changed, 18 insertions(+), 21 deletions(-)

diff --git a/gcc/system.h b/gcc/system.h
index b13e9429577..28c721565a4 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
@@ -244,6 +228,19 @@ 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