diff options
| author | Patrick Simmons <psimmons@pensando.io> | 2025-10-16 11:24:06 -0500 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2025-10-16 18:24:06 +0200 |
| commit | be3aa41ecc9b6cc68248e660a30829a16eda26b3 (patch) | |
| tree | e455beadda4497aa1c384ef2c9c2b8225b1a54f7 /flang-rt | |
| parent | 8fa4a1029cbad3c788a90152cf978f8233a6f87f (diff) | |
[Flang-RT] Fix GCC 15.1 Fortran Runtime libstdc++ Undefined Symbols (#157385)
Define the _GLIBCXX_THROW_OR_ABORT macro to not use its _EXC argument. _EXC may contain an expression constructing an std::exception object which is non-inline and therefore require a link dependency on the libstdc++ runtime. In -fno-exceptions builds it is typically optimized away when appearing in unreachable code, but is still present when compiling with -O0 when compiling with Clang.
---------
Co-authored-by: Michael Kruse <github@meinersbur.de>
Diffstat (limited to 'flang-rt')
| -rw-r--r-- | flang-rt/cmake/modules/AddFlangRT.cmake | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/flang-rt/cmake/modules/AddFlangRT.cmake b/flang-rt/cmake/modules/AddFlangRT.cmake index ab383bcbe2cd..923507764d69 100644 --- a/flang-rt/cmake/modules/AddFlangRT.cmake +++ b/flang-rt/cmake/modules/AddFlangRT.cmake @@ -231,6 +231,27 @@ function (add_flangrt_library name) target_compile_options(${tgtname} PRIVATE $<$<COMPILE_LANGUAGE:CXX>:-fno-exceptions -fno-rtti -funwind-tables -fno-asynchronous-unwind-tables> ) + + # We define our own _GLIBCXX_THROW_OR_ABORT here because, as of + # GCC 15.1, the libstdc++ header file <bits/c++config> uses + # (void)_EXC in its definition of _GLIBCXX_THROW_OR_ABORT to + # silence a warning. + # + # This is a problem for us because some compilers, specifically + # clang, do not always optimize away that (void)_EXC even though + # it is unreachable since it occurs after a call to + # _builtin_abort(). Because _EXC is typically an object derived + # from std::exception, (void)_EXC, when not optimized away, + # calls std::exception methods defined in the libstdc++ shared + # library. We shouldn't link against that library since our + # build version may conflict with the version used by a hybrid + # Fortran/C++ application. + # + # Redefining _GLIBCXX_THROW_OR_ABORT in this manner is not + # supported by the maintainers of libstdc++, so future changes + # to libstdc++ may require future changes to this build script + # and/or future changes to the Fortran runtime source code. + target_compile_options(${tgtname} PUBLIC "-D_GLIBCXX_THROW_OR_ABORT(_EXC)=(__builtin_abort())") elseif (MSVC) target_compile_options(${tgtname} PRIVATE $<$<COMPILE_LANGUAGE:CXX>:/EHs-c- /GR-> |