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| author | Saleem Abdulrasool <compnerd@compnerd.org> | 2016-08-23 23:01:16 +0000 |
|---|---|---|
| committer | Saleem Abdulrasool <compnerd@compnerd.org> | 2016-08-23 23:01:16 +0000 |
| commit | 12a0b1f4c847a3dd8efc53b2fe1746fea7f2edc5 (patch) | |
| tree | fab31351da98ca802a5511e3f66ade40242b9f4f /libcxx | |
| parent | 84c4cc47f5fb52e680ca3f3790a7e15a3499731f (diff) | |
| download | bcm5719-llvm-12a0b1f4c847a3dd8efc53b2fe1746fea7f2edc5.tar.gz bcm5719-llvm-12a0b1f4c847a3dd8efc53b2fe1746fea7f2edc5.zip | |
libc++: Perform configuration checks with -nodefaultlibs
We're compiling libc++ with -nodefaultlibs, so we should also pass this option
during the configuration checks to ensure those checks are consistent with the
actual build.
The primary motivation here is to ease cross-compilation against a non-standard
set of C++ libraries. Previously, the configuration checks would attempt to link
against the standard C++ libraries, which would cause link failures when
cross-compiling, even though the actual library link would go through correctly
(because of the use of -nodefaultlibs and explicitly specifying any needed
libraries). This is more correct even ignoring the motivation, however.
Patch by Shoaib Meenai!
llvm-svn: 279584
Diffstat (limited to 'libcxx')
| -rw-r--r-- | libcxx/cmake/config-ix.cmake | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/libcxx/cmake/config-ix.cmake b/libcxx/cmake/config-ix.cmake index 3e6c3599d23..b4c9ac482cf 100644 --- a/libcxx/cmake/config-ix.cmake +++ b/libcxx/cmake/config-ix.cmake @@ -1,5 +1,26 @@ include(CheckLibraryExists) include(CheckCXXCompilerFlag) + +check_library_exists(c fopen "" LIBCXX_HAS_C_LIB) +check_library_exists(gcc_s __gcc_personality_v0 "" LIBCXX_HAS_GCC_S_LIB) + +# libc++ is built with -nodefaultlibs, so we want all our checks to also +# use this option, otherwise we may end up with an inconsistency between +# the flags we think we require during configuration (if the checks are +# performed without -nodefaultlibs) and the flags that are actually +# required during compilation (which has the -nodefaultlibs). libc is +# required for the link to go through. +check_cxx_compiler_flag(-nodefaultlibs LIBCXX_SUPPORTS_NODEFAULTLIBS_FLAG) +if (LIBCXX_SUPPORTS_NODEFAULTLIBS_FLAG) + list(APPEND CMAKE_REQUIRED_LIBRARIES -nodefaultlibs) + if (LIBCXX_HAS_C_LIB) + list(APPEND CMAKE_REQUIRED_LIBRARIES c) + endif () + if (LIBCXX_HAS_GCC_S_LIB) + list(APPEND CMAKE_REQUIRED_LIBRARIES gcc_s) + endif () +endif () + include(CheckLibcxxAtomic) # Check compiler flags @@ -14,7 +35,5 @@ check_cxx_compiler_flag(/GR- LIBCXX_HAS_NO_GR_FLAG) # Check libraries check_library_exists(pthread pthread_create "" LIBCXX_HAS_PTHREAD_LIB) -check_library_exists(c fopen "" LIBCXX_HAS_C_LIB) check_library_exists(m ccos "" LIBCXX_HAS_M_LIB) check_library_exists(rt clock_gettime "" LIBCXX_HAS_RT_LIB) -check_library_exists(gcc_s __gcc_personality_v0 "" LIBCXX_HAS_GCC_S_LIB) |
