caio/clang-p2996
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

[runtimes] Probe for -nostdlib++ and -nostdinc++ with the C compiler (#108357)

Browse Source 
While these flags semantically are relevant only for C++, we do add them
to CMAKE_REQUIRED_FLAGS if they are detected. All flags in that variable
are used both when testing compilation of C and C++ (and for detecting
libraries, which uses the C compiler driver).

Therefore, to be sure we safely can add the flags to
CMAKE_REQUIRED_FLAGS, test for the option with the C language.

This should fix compilation with GCC; newer versions of GCC do support
the -nostdlib++ option, but it's only supported by the C++ compiler
driver, not the C driver. (However, many builds of GCC also do accept
the option with the C driver, if GCC was compiled with Ada support
enabled, see [1]. That's why this issue isn't noticed in all
configurations with GCC.)

Clang does support these options in both C and C++ driver modes.

This should fix #90332.

[1]
https://github.com/llvm/llvm-project/issues/90332#issuecomment-2325099254
This commit is contained in:
Martin Storsjö
2024-10-24 23:46:04 +03:00
committed by GitHub
parent a14a83d9a1
commit 75d0281bc8
6 changed files with 35 additions and 19 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
runtimes/CMakeLists.txt
View File

@@ -143,12 +143,16 @@ endif()
# Check for -nostdlib++ first; if there's no C++ standard library yet,
# all check_cxx_compiler_flag commands will fail until we add -nostdlib++
# (or -nodefaultlibs).
llvm_check_compiler_linker_flag(CXX "-nostdlib++" CXX_SUPPORTS_NOSTDLIBXX_FLAG)
if (CXX_SUPPORTS_NOSTDLIBXX_FLAG)
#
# Adding flags to CMAKE_REQUIRED_FLAGS will include the flags both when testing
# compilation of C and C++. Therefore test to make sure that the flags are
# supported by the C compiler driver, before deciding to include them.
llvm_check_compiler_linker_flag(C "-nostdlib++" C_SUPPORTS_NOSTDLIBXX_FLAG)
if (C_SUPPORTS_NOSTDLIBXX_FLAG)
set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -nostdlib++")
endif()
check_cxx_compiler_flag(-nostdinc++ CXX_SUPPORTS_NOSTDINCXX_FLAG)
if (CXX_SUPPORTS_NOSTDINCXX_FLAG)
check_c_compiler_flag(-nostdinc++ C_SUPPORTS_NOSTDINCXX_FLAG)
if (C_SUPPORTS_NOSTDINCXX_FLAG)
set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -nostdinc++")
endif()