Re: [committed] libstdc++: Ensure __glibcxx_assert_fail has default visibility

[Jonathan Wakely <jwakely@redhat.com>]

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On Sat, 5 Mar 2022 at 20:34, Jonathan Wakely via Libstdc++
<libstdc++@gcc.gnu.org> wrote:
>
> Tested powerpc64le-linux, pushed to trunk.
>
> -- >8 --
>
> This ensures there's no linker error if libstdc++ headers are included
> following a pragma that sets hidden visibility.
>
> Similarly for std::__terminate, which is always-inline so shouldn't
> matter, but it's not wrong to do this anyway.
>
> libstdc++-v3/ChangeLog:
>
>         * include/bits/c++config (__glibcxx_assert_fail): Add visibility
>         attribute.
>         (__terminate): Likewise.

This broke mingw targets. Fixed like so.

Tested x86_64-linux, pushed to trunk.

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commit 4cb935cb69f12088975fa7f6907c6ace0580e2dd
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Mon Mar 7 15:07:05 2022

    libstdc++: Use visibility pragmas instead of attributes [PR104807]
    
    The _GLIBCXX_PSEUDO_VISIBILITY macro isn't defined until after including
    os_defines.h, so we can't use _GLIBCXX_VISIBILITY early in c++config.
    Replace the uses of that macro with #pragma visibility push(default)
    instead.
    
    libstdc++-v3/ChangeLog:
    
            PR libstdc++/104807
            * include/bits/c++config (__terminate, __glibcxx_assert_fail):
            Replace _GLIBCXX_VISIBILITY on function with visibility pragma.
            (__is_constant_evaluated): Add visibility pragma.

diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config
index 6c134f13509..2798b9786dc 100644
--- a/libstdc++-v3/include/bits/c++config
+++ b/libstdc++-v3/include/bits/c++config
@@ -302,15 +302,16 @@ namespace std
   typedef decltype(nullptr)	nullptr_t;
 #endif
 
+#pragma GCC visibility push(default)
   // This allows the library to terminate without including all of <exception>
   // and without making the declaration of std::terminate visible to users.
   extern "C++" __attribute__ ((__noreturn__, __always_inline__))
-  _GLIBCXX_VISIBILITY(default)
   inline void __terminate() _GLIBCXX_USE_NOEXCEPT
   {
     void terminate() _GLIBCXX_USE_NOEXCEPT __attribute__ ((__noreturn__));
     terminate();
   }
+#pragma GCC visibility pop
 }
 
 #define _GLIBCXX_USE_DUAL_ABI
@@ -506,6 +507,7 @@ namespace std
 
 namespace std
 {
+#pragma GCC visibility push(default)
   // Internal version of std::is_constant_evaluated().
   // This can be used without checking if the compiler supports the feature.
   // The macro _GLIBCXX_HAVE_IS_CONSTANT_EVALUATED can be used to check if
@@ -523,6 +525,7 @@ namespace std
     return false;
 #endif
   }
+#pragma GCC visibility pop
 }
 
 // Debug Mode implies checking assertions.
@@ -553,13 +556,15 @@ namespace std
 # ifdef _GLIBCXX_VERBOSE_ASSERT
 namespace std
 {
+#pragma GCC visibility push(default)
   // Avoid the use of assert, because we're trying to keep the <cassert>
   // include out of the mix.
-  extern "C++" _GLIBCXX_NORETURN _GLIBCXX_VISIBILITY(default)
+  extern "C++" _GLIBCXX_NORETURN
   void
   __glibcxx_assert_fail(const char* __file, int __line,
 			const char* __function, const char* __condition)
   _GLIBCXX_NOEXCEPT;
+#pragma GCC visibility pop
 }
 #define __glibcxx_assert_impl(_Condition)				\
   if (__builtin_expect(!bool(_Condition), false))			\