error: cannot add 'abi_tag' attribute in a redeclaration

[stbergmann]

Please include the following in your bug report:

Version of emscripten/emsdk:

$ emcc -v
emcc (Emscripten gcc/clang-like replacement + linker emulating GNU ld) 4.0.0-git (1fb631cdf803fd343b08179bc2b73ea6211487ce)
clang version 20.0.0git (/home/sberg/emsdk/4.0.0/sources//llvm-project 322eb1a92e6d4266184060346616fa0dbe39e731)
Target: wasm32-unknown-emscripten
Thread model: posix
InstalledDir: /home/sberg/emsdk/4.0.0/emsdk/llvm/git/build_main_64/bin

Failing command line in full:

$ cat test.cc
#include <xlocale.h>
#include <locale>

$ em++ -fsyntax-only test.cc
In file included from test.cc:2:
In file included from /home/sberg/emsdk/4.0.0/emsdk/emscripten/main/cache/sysroot/include/c++/v1/locale:205:
In file included from /home/sberg/emsdk/4.0.0/emsdk/emscripten/main/cache/sysroot/include/c++/v1/__locale:14:
In file included from /home/sberg/emsdk/4.0.0/emsdk/emscripten/main/cache/sysroot/include/c++/v1/__locale_dir/locale_base_api.h:27:
/home/sberg/emsdk/4.0.0/emsdk/emscripten/main/cache/sysroot/include/c++/v1/__locale_dir/locale_base_api/musl.h:23:8: error: cannot add 'abi_tag' attribute in a redeclaration
   23 | inline _LIBCPP_HIDE_FROM_ABI long long strtoll_l(const char* __nptr, char** __endptr, int __base, locale_t) {
      |        ^
/home/sberg/emsdk/4.0.0/emsdk/emscripten/main/cache/sysroot/include/c++/v1/__config:545:22: note: expanded from macro '_LIBCPP_HIDE_FROM_ABI'
  545 |       __attribute__((__abi_tag__(_LIBCPP_TOSTRING(_LIBCPP_ODR_SIGNATURE))))
      |                      ^
/home/sberg/emsdk/4.0.0/emsdk/emscripten/main/cache/sysroot/include/compat/xlocale.h:13:11: note: previous declaration is here
   13 | long long strtoll_l(const char *start, char **end, int base, locale_t loc);
      |           ^
In file included from test.cc:2:
In file included from /home/sberg/emsdk/4.0.0/emsdk/emscripten/main/cache/sysroot/include/c++/v1/locale:205:
In file included from /home/sberg/emsdk/4.0.0/emsdk/emscripten/main/cache/sysroot/include/c++/v1/__locale:14:
In file included from /home/sberg/emsdk/4.0.0/emsdk/emscripten/main/cache/sysroot/include/c++/v1/__locale_dir/locale_base_api.h:27:
/home/sberg/emsdk/4.0.0/emsdk/emscripten/main/cache/sysroot/include/c++/v1/__locale_dir/locale_base_api/musl.h:27:8: error: cannot add 'abi_tag' attribute in a redeclaration
   27 | inline _LIBCPP_HIDE_FROM_ABI unsigned long long strtoull_l(const char* __nptr, char** __endptr, int __base, locale_t) {
      |        ^
/home/sberg/emsdk/4.0.0/emsdk/emscripten/main/cache/sysroot/include/c++/v1/__config:545:22: note: expanded from macro '_LIBCPP_HIDE_FROM_ABI'
  545 |       __attribute__((__abi_tag__(_LIBCPP_TOSTRING(_LIBCPP_ODR_SIGNATURE))))
      |                      ^
/home/sberg/emsdk/4.0.0/emsdk/emscripten/main/cache/sysroot/include/compat/xlocale.h:14:20: note: previous declaration is here
   14 | unsigned long long strtoull_l(const char *start, char **end, int base, locale_t loc);
      |                    ^
2 errors generated.

[sbc100]

Fix is in #23414.

This made me wonder if we really should be including xlocale.h in our SDK. Can I ask if/how/why you are depending on it? IIUC, this header doesn't exist on linux.

[stbergmann]

Fix is in #23414.

thanks!

This made me wonder if we really should be including xlocale.h in our SDK. Can I ask if/how/why you are depending on it? IIUC, this header doesn't exist on linux.

I stumbled across this issue when building LibreOffice, which has its own bundled Harfbuzz, which in turn has an Autotools check for xlocale.h and in it's central src/hb.hh does

#include <locale.h>
#ifdef HAVE_XLOCALE_H
#include <xlocale.h> // Needed on BSD/OS X for uselocale
#endif

So that use case would probably be fine with no xlocale.h in Emscripten, and just happened to get caught up by it being present.