diff --git a/libunwind/CMakeLists.txt b/libunwind/CMakeLists.txt --- a/libunwind/CMakeLists.txt +++ b/libunwind/CMakeLists.txt @@ -21,7 +21,12 @@ "Specify path to libc++ source.") if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR OR LIBUNWIND_STANDALONE_BUILD) + # We may have an incomplete toolchain - skip linking testing when doing + # compiler sanity checks and ABI inspections. + set(CMAKE_TRY_COMPILE_TARGET_TYPE_ORIG ${CMAKE_TRY_COMPILE_TARGET_TYPE}) + set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY) project(libunwind LANGUAGES C CXX ASM) + set(CMAKE_TRY_COMPILE_TARGET_TYPE ${CMAKE_TRY_COMPILE_TARGET_TYPE_ORIG}) set(PACKAGE_NAME libunwind) set(PACKAGE_VERSION 14.0.0git) @@ -171,6 +176,14 @@ # Get required flags. add_target_flags_if(LIBUNWIND_BUILD_32_BITS "-m32") +# Compiler tests may be failing if the compiler implicitly links in libunwind, +# which doesn't exist yet. This gets waived by --unwindlib=none +# later in config-ix below, but the tests for --target etc before that may +# be failing due to it. Only test compilation, not linking, for these +# tests here now. +set(CMAKE_TRY_COMPILE_TARGET_TYPE_ORIG ${CMAKE_TRY_COMPILE_TARGET_TYPE}) +set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY) + if(LIBUNWIND_TARGET_TRIPLE) add_target_flags_if_supported("--target=${LIBUNWIND_TARGET_TRIPLE}") endif() @@ -180,6 +193,7 @@ if(LIBUNWIND_SYSROOT) add_target_flags_if_supported("--sysroot=${LIBUNWIND_SYSROOT}") endif() +set(CMAKE_TRY_COMPILE_TARGET_TYPE ${CMAKE_TRY_COMPILE_TARGET_TYPE_ORIG}) # Configure compiler. include(config-ix) diff --git a/libunwind/cmake/Modules/CheckCLinkerFlag.cmake b/libunwind/cmake/Modules/CheckCLinkerFlag.cmake new file mode 100644 --- /dev/null +++ b/libunwind/cmake/Modules/CheckCLinkerFlag.cmake @@ -0,0 +1,17 @@ +include(CMakePushCheckState) +include(CheckCCompilerFlag) + +function(check_c_linker_flag flag dest) + # If testing a flag with check_c_compiler_flag, it gets added to the compile + # command only, but not to the linker command in that test. If the flag + # is vital for linking to succeed, the test would fail even if it would + # have succeeded if it was included on both commands. + # + # Therefore, try adding the flag to CMAKE_REQUIRED_FLAGS, which gets + # added to both compiling and linking commands in the tests. + + cmake_push_check_state() + set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} ${flag}") + check_c_compiler_flag("" ${dest}) + cmake_pop_check_state() +endfunction() diff --git a/libunwind/cmake/config-ix.cmake b/libunwind/cmake/config-ix.cmake --- a/libunwind/cmake/config-ix.cmake +++ b/libunwind/cmake/config-ix.cmake @@ -1,10 +1,19 @@ include(CMakePushCheckState) include(CheckCCompilerFlag) +include(CheckCLinkerFlag) include(CheckCXXCompilerFlag) include(CheckLibraryExists) include(CheckSymbolExists) include(CheckCSourceCompiles) +# The compiler driver may be implicitly trying to link against libunwind, which +# might not work if libunwind doesn't exist yet. Try to check if +# --unwindlib=none is supported, and use that if possible. +check_c_linker_flag("--unwindlib=none" LIBUNWIND_SUPPORTS_UNWINDLIB_NONE_FLAG) +if (LIBUNWIND_SUPPORTS_UNWINDLIB_NONE_FLAG) + set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} --unwindlib=none") +endif() + check_library_exists(c fopen "" LIBUNWIND_HAS_C_LIB) if (NOT LIBUNWIND_USE_COMPILER_RT) @@ -25,11 +34,11 @@ # required for the link to go through. We remove sanitizers from the # configuration checks to avoid spurious link errors. -check_c_compiler_flag(-nostdlib++ LIBUNWIND_SUPPORTS_NOSTDLIBXX_FLAG) +check_c_linker_flag(-nostdlib++ LIBUNWIND_SUPPORTS_NOSTDLIBXX_FLAG) if (LIBUNWIND_SUPPORTS_NOSTDLIBXX_FLAG) set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -nostdlib++") else() - check_c_compiler_flag(-nodefaultlibs LIBUNWIND_SUPPORTS_NODEFAULTLIBS_FLAG) + check_c_linker_flag(-nodefaultlibs LIBUNWIND_SUPPORTS_NODEFAULTLIBS_FLAG) if (LIBUNWIND_SUPPORTS_NODEFAULTLIBS_FLAG) set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -nodefaultlibs") endif() diff --git a/libunwind/src/CMakeLists.txt b/libunwind/src/CMakeLists.txt --- a/libunwind/src/CMakeLists.txt +++ b/libunwind/src/CMakeLists.txt @@ -83,6 +83,7 @@ endif() # Setup flags. +add_link_flags_if(LIBUNWIND_SUPPORTS_UNWINDLIB_NONE_FLAG --unwindlib=none) if (LIBUNWIND_SUPPORTS_NOSTDLIBXX_FLAG) add_link_flags_if_supported(-nostdlib++) else()