diff options
| -rw-r--r-- | libcxx/CMakeLists.txt | 7 | ||||
| -rw-r--r-- | libcxx/cmake/config-ix.cmake | 13 | ||||
| -rw-r--r-- | runtimes/CMakeLists.txt | 19 |
3 files changed, 38 insertions, 1 deletions
diff --git a/libcxx/CMakeLists.txt b/libcxx/CMakeLists.txt index b28dd00..39744bb 100644 --- a/libcxx/CMakeLists.txt +++ b/libcxx/CMakeLists.txt @@ -765,6 +765,13 @@ function(cxx_link_system_libraries target) target_add_link_flags_if_supported(${target} PRIVATE "/nodefaultlib") endif() + if (LIBCXX_SUPPORTS_UNWINDLIB_NONE_FLAG AND LIBCXXABI_USE_LLVM_UNWINDER) + # If we're linking directly against the libunwind that we're building + # in the same invocation, don't try to link in the toolchain's + # default libunwind (which may be missing still). + target_add_link_flags_if_supported(${target} PRIVATE "--unwindlib=none") + endif() + if (LIBCXX_HAS_SYSTEM_LIB) target_link_libraries(${target} PRIVATE System) endif() diff --git a/libcxx/cmake/config-ix.cmake b/libcxx/cmake/config-ix.cmake index 8ca8b14..167ea81 100644 --- a/libcxx/cmake/config-ix.cmake +++ b/libcxx/cmake/config-ix.cmake @@ -1,9 +1,22 @@ include(CMakePushCheckState) include(CheckLibraryExists) +include(CheckLinkerFlag) include(CheckCCompilerFlag) include(CheckCXXCompilerFlag) include(CheckCSourceCompiles) +# The compiler driver may be implicitly trying to link against libunwind. +# This is normally ok (libcxx relies on an unwinder), but if libunwind is +# built in the same cmake invocation as libcxx and we've got +# LIBCXXABI_USE_LLVM_UNWINDER set, we'd be linking against the just-built +# libunwind (and the compiler implicit -lunwind wouldn't succeed as the newly +# built libunwind isn't installed yet). For those cases, it'd be good to +# link with --uwnindlib=none. Check if that option works. +llvm_check_linker_flag("--unwindlib=none" LIBCXX_SUPPORTS_UNWINDLIB_NONE_FLAG) +if (LIBCXX_SUPPORTS_UNWINDLIB_NONE_FLAG) + set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} --unwindlib=none") +endif() + if(WIN32 AND NOT MINGW) # NOTE(compnerd) this is technically a lie, there is msvcrt, but for now, lets # let the default linking take care of that. diff --git a/runtimes/CMakeLists.txt b/runtimes/CMakeLists.txt index eeaff6c..8f37d0e 100644 --- a/runtimes/CMakeLists.txt +++ b/runtimes/CMakeLists.txt @@ -32,6 +32,8 @@ find_package(Clang PATHS "${LLVM_BINARY_DIR}" NO_DEFAULT_PATH NO_CMAKE_FIND_ROOT list(INSERT CMAKE_MODULE_PATH 0 "${CMAKE_CURRENT_SOURCE_DIR}/cmake" "${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules" + "${CMAKE_CURRENT_SOURCE_DIR}/../cmake" + "${CMAKE_CURRENT_SOURCE_DIR}/../cmake/Modules" "${CMAKE_CURRENT_SOURCE_DIR}/../llvm/cmake" "${CMAKE_CURRENT_SOURCE_DIR}/../llvm/cmake/modules" ) @@ -84,14 +86,29 @@ set(LLVM_CMAKE_DIR ${LLVM_MAIN_SRC_DIR}/cmake/modules) set(LLVM_PATH ${CMAKE_CURRENT_SOURCE_DIR}/../llvm) include(CheckLibraryExists) +include(CheckLinkerFlag) include(CheckCCompilerFlag) include(CheckCXXCompilerFlag) + +check_c_compiler_flag("" LLVM_RUNTIMES_LINKING_WORKS) +if (NOT LLVM_RUNTIMES_LINKING_WORKS) + # The compiler driver may be implicitly trying to link against libunwind, which + # might not work if libunwind doesn't exist yet. Try to check if + # --unwindlib=none is supported, and use that if possible. + # Don't add this if not necessary to fix linking, as it can break using + # e.g. ASAN/TSAN. + llvm_check_linker_flag("--unwindlib=none" LLVM_RUNTIMES_SUPPORT_UNWINDLIB_NONE_FLAG) + if (LLVM_RUNTIMES_SUPPORT_UNWINDLIB_NONE_FLAG) + set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} --unwindlib=none") + endif() +endif() + # Disable use of the installed C++ standard library when building runtimes. # 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). -check_c_compiler_flag(-nostdlib++ LLVM_RUNTIMES_SUPPORT_NOSTDLIBXX_FLAG) +llvm_check_linker_flag(-nostdlib++ LLVM_RUNTIMES_SUPPORT_NOSTDLIBXX_FLAG) if (LLVM_RUNTIMES_SUPPORT_NOSTDLIBXX_FLAG) set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -nostdlib++") endif() |