diff options
Diffstat (limited to 'cmake')
| -rw-r--r-- | cmake/modules/HandleLLVMOptions.cmake | 37 |
1 files changed, 27 insertions, 10 deletions
diff --git a/cmake/modules/HandleLLVMOptions.cmake b/cmake/modules/HandleLLVMOptions.cmake index 50a8541206b9..d776285b80fe 100644 --- a/cmake/modules/HandleLLVMOptions.cmake +++ b/cmake/modules/HandleLLVMOptions.cmake @@ -12,6 +12,12 @@ include(AddLLVMDefinitions) include(CheckCCompilerFlag) include(CheckCXXCompilerFlag) +if(CMAKE_LINKER MATCHES "lld-link.exe" OR (WIN32 AND LLVM_USE_LINKER STREQUAL "lld")) + set(LINKER_IS_LLD_LINK TRUE) +else() + set(LINKER_IS_LLD_LINK FALSE) +endif() + # Ninja Job Pool support # The following only works with the Ninja generator in CMake >= 3.0. set(LLVM_PARALLEL_COMPILE_JOBS "" CACHE STRING @@ -37,7 +43,7 @@ if(LLVM_PARALLEL_LINK_JOBS) endif() -if (CMAKE_LINKER MATCHES "lld-link.exe") +if (LINKER_IS_LLD_LINK) # Pass /MANIFEST:NO so that CMake doesn't run mt.exe on our binaries. Adding # manifests with mt.exe breaks LLD's symbol tables and takes as much time as # the link. See PR24476. @@ -407,11 +413,13 @@ if( MSVC ) # "Enforce type conversion rules". append("/Zc:rvalueCast" CMAKE_CXX_FLAGS) - if (CMAKE_CXX_COMPILER_ID MATCHES "Clang") + if (CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND NOT LLVM_ENABLE_LTO) # clang-cl and cl by default produce non-deterministic binaries because # link.exe /incremental requires a timestamp in the .obj file. clang-cl # has the flag /Brepro to force deterministic binaries. We want to pass that - # whenever you're building with clang unless you're passing /incremental. + # whenever you're building with clang unless you're passing /incremental + # or using LTO (/Brepro with LTO would result in a warning about the flag + # being unused, because we're not generating object files). # This checks CMAKE_CXX_COMPILER_ID in addition to check_cxx_compiler_flag() # because cl.exe does not emit an error on flags it doesn't understand, # letting check_cxx_compiler_flag() claim it understands all flags. @@ -561,7 +569,7 @@ macro(append_common_sanitizer_flags) elseif (CLANG_CL) # Keep frame pointers around. append("/Oy-" CMAKE_C_FLAGS CMAKE_CXX_FLAGS) - if (CMAKE_LINKER MATCHES "lld-link.exe") + if (LINKER_IS_LLD_LINK) # Use DWARF debug info with LLD. append("-gdwarf" CMAKE_C_FLAGS CMAKE_CXX_FLAGS) else() @@ -699,20 +707,29 @@ append_if(LLVM_BUILD_INSTRUMENTED_COVERAGE "-fprofile-instr-generate='${LLVM_PRO set(LLVM_ENABLE_LTO OFF CACHE STRING "Build LLVM with LTO. May be specified as Thin or Full to use a particular kind of LTO") string(TOUPPER "${LLVM_ENABLE_LTO}" uppercase_LLVM_ENABLE_LTO) +if(LLVM_ENABLE_LTO AND LLVM_ON_WIN32 AND NOT LINKER_IS_LLD_LINK) + message(FATAL_ERROR "When compiling for Windows, LLVM_ENABLE_LTO requires using lld as the linker (point CMAKE_LINKER at lld-link.exe)") +endif() if(uppercase_LLVM_ENABLE_LTO STREQUAL "THIN") - append("-flto=thin" CMAKE_CXX_FLAGS CMAKE_C_FLAGS - CMAKE_EXE_LINKER_FLAGS CMAKE_SHARED_LINKER_FLAGS) + append("-flto=thin" CMAKE_CXX_FLAGS CMAKE_C_FLAGS) + if(NOT LINKER_IS_LLD_LINK) + append("-flto=thin" CMAKE_EXE_LINKER_FLAGS CMAKE_SHARED_LINKER_FLAGS) + endif() # On darwin, enable the lto cache. This improves initial build time a little # since we re-link a lot of the same objects, and significantly improves # incremental build time. append_if(APPLE "-Wl,-cache_path_lto,${PROJECT_BINARY_DIR}/lto.cache" CMAKE_EXE_LINKER_FLAGS CMAKE_SHARED_LINKER_FLAGS) elseif(uppercase_LLVM_ENABLE_LTO STREQUAL "FULL") - append("-flto=full" CMAKE_CXX_FLAGS CMAKE_C_FLAGS - CMAKE_EXE_LINKER_FLAGS CMAKE_SHARED_LINKER_FLAGS) + append("-flto=full" CMAKE_CXX_FLAGS CMAKE_C_FLAGS) + if(NOT LINKER_IS_LLD_LINK) + append("-flto=full" CMAKE_EXE_LINKER_FLAGS CMAKE_SHARED_LINKER_FLAGS) + endif() elseif(LLVM_ENABLE_LTO) - append("-flto" CMAKE_CXX_FLAGS CMAKE_C_FLAGS - CMAKE_EXE_LINKER_FLAGS CMAKE_SHARED_LINKER_FLAGS) + append("-flto" CMAKE_CXX_FLAGS CMAKE_C_FLAGS) + if(NOT LINKER_IS_LLD_LINK) + append("-flto" CMAKE_EXE_LINKER_FLAGS CMAKE_SHARED_LINKER_FLAGS) + endif() endif() # This option makes utils/extract_symbols.py be used to determine the list of |