https://gcc.gnu.org/g:fc7a1fb0238e379d466316aa219734ac61f4bc0e
commit r15-3576-gfc7a1fb0238e379d466316aa219734ac61f4bc0e
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Tue Sep 10 14:36:26 2024 +0100
libstdc++: Only use std::ios_base_library_init() for ELF [PR116159]
The undefined std::ios_base_library_init() symbol that is referenced by
<iostream> is only supposed to be used for targets where symbol
versioning is supported.
The mingw-w64 target defaults to --enable-symvers=gnu due to using GNU
ld but doesn't actually support symbol versioning. This means it tries
to emit references to the std::ios_base_library_init() symbol, which
isn't really defined in the library. This causes problems when using lld
to link user binaries.
Disable the undefined symbol reference for non-ELF targets.
libstdc++-v3/ChangeLog:
PR libstdc++/116159
* include/std/iostream (ios_base_library_init): Only define for
ELF targets.
* src/c++98/ios_init.cc (ios_base_library_init): Likewise.
Diff:
---
libstdc++-v3/include/std/iostream | 2 +-
libstdc++-v3/src/c++98/ios_init.cc | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/libstdc++-v3/include/std/iostream
b/libstdc++-v3/include/std/iostream
index 4f4fa6880d57..4a6dc584d38a 100644
--- a/libstdc++-v3/include/std/iostream
+++ b/libstdc++-v3/include/std/iostream
@@ -78,7 +78,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
#if !(_GLIBCXX_USE_INIT_PRIORITY_ATTRIBUTE \
&& __has_attribute(__init_priority__))
static ios_base::Init __ioinit;
-#elif defined(_GLIBCXX_SYMVER_GNU)
+#elif defined(_GLIBCXX_SYMVER_GNU) && defined(__ELF__)
__extension__ __asm (".globl _ZSt21ios_base_library_initv");
#endif
diff --git a/libstdc++-v3/src/c++98/ios_init.cc
b/libstdc++-v3/src/c++98/ios_init.cc
index 1422e20d9405..6e2e5014cf0f 100644
--- a/libstdc++-v3/src/c++98/ios_init.cc
+++ b/libstdc++-v3/src/c++98/ios_init.cc
@@ -199,7 +199,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return __ret;
}
-#ifdef _GLIBCXX_SYMVER_GNU
+#if defined(_GLIBCXX_SYMVER_GNU) && defined(__ELF__)
#pragma GCC diagnostic ignored "-Wattribute-alias"
void ios_base_library_init (void)
