1 files changed, 77 insertions, 0 deletions
diff --git a/cmake/modules/buildtools/MOLD.cmake b/cmake/modules/buildtools/MOLD.cmake
new file mode 100644
index 0000000..cb29ed1
--- /dev/null
+++ b/cmake/modules/buildtools/MOLD.cmake
@@ -0,0 +1,77 @@
+if(ENABLE_MOLD)
+  if(CMAKE_COMPILER_IS_GNUCXX AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS 12)
+    # GCC < 12 doesn't support -fuse-ld=mold, so we have to use tools prefix path
+    # if mold is installed in a non-standard dir, users can set -DMOLD_PREFIX=/path/to/mold_install_prefix
+    find_path(MOLD_PREFIX_DIR NAMES ld
+                              NO_DEFAULT_PATH # this is needed, otherwise we find /usr/bin/ld
+                              PATH_SUFFIXES libexec/mold
+                              PATHS ${MOLD_PREFIX} /usr /usr/local)
+    if(MOLD_PREFIX_DIR)
+      set(COMPILER_ARGS "-B${MOLD_PREFIX_DIR}")
+    else()
+      message(WARNING "Mold LD path not found, you might need to set -DMOLD_PREFIX=/path/to/mold_install_prefix")
+    endif()
+  else()
+    set(COMPILER_ARGS "-fuse-ld=mold")
+  endif()
+
+  execute_process(COMMAND ${CMAKE_CXX_COMPILER} ${COMPILER_ARGS} -Wl,--version ERROR_QUIET OUTPUT_VARIABLE LD_VERSION)
+
+  set(DEFAULT_ENABLE_DEBUGFISSION FALSE)
+  if(CMAKE_BUILD_TYPE STREQUAL Debug OR
+     CMAKE_BUILD_TYPE STREQUAL RelWithDebInfo)
+    set(DEFAULT_ENABLE_DEBUGFISSION TRUE)
+  endif()
+
+  include(CMakeDependentOption)
+  cmake_dependent_option(ENABLE_DEBUGFISSION "Enable Debug Fission support" ON
+                         "DEFAULT_ENABLE_DEBUGFISSION" OFF)
+
+  if(ENABLE_DEBUGFISSION)
+    include(TestCXXAcceptsFlag)
+    check_cxx_accepts_flag(-gsplit-dwarf CXX_ACCEPTS_GSPLIT_DWARF)
+
+    # extract mold version
+    set(LD_VERSION_LIST ${LD_VERSION})
+    separate_arguments(LD_VERSION_LIST)
+    list(GET LD_VERSION_LIST 1 MOLD_VERSION)
+
+    set(DEBUGFISSION_AVAILABLE FALSE)
+    if(CXX_ACCEPTS_GSPLIT_DWARF)
+      set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -gsplit-dwarf")
+      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -gsplit-dwarf")
+      if(${MOLD_VERSION} VERSION_GREATER_EQUAL "1.2.0")
+        set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,--gdb-index")
+        set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,--gdb-index")
+        set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,--gdb-index")
+        set(DEBUGFISSION_AVAILABLE TRUE)
+      endif()
+    endif()
+
+    if(DEBUGFISSION_AVAILABLE)
+      message(STATUS "Debug Fission enabled")
+    else()
+      message(WARNING "Debug Fission is not available")
+    endif()
+  endif()
+
+  if(LD_VERSION MATCHES "mold")
+    include(FindPackageHandleStandardArgs)
+    find_program(MOLD_EXECUTABLE mold)
+    find_package_handle_standard_args(MOLD REQUIRED_VARS MOLD_EXECUTABLE)
+
+    if(MOLD_FOUND)
+      set(CMAKE_LINKER ${MOLD_EXECUTABLE})
+      set(CMAKE_CXX_LINK_FLAGS ${COMPILER_ARGS})
+      set(CMAKE_C_LINK_FLAGS ${COMPILER_ARGS})
+      set(CMAKE_EXE_LINKER_FLAGS "${LD_FLAGS} ${COMPILER_ARGS} ${CMAKE_EXE_LINKER_FLAGS}")
+      set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS}")
+      set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS}")
+      message(STATUS "Linker: mold")
+    endif()
+    mark_as_advanced(MOLD_EXECUTABLE CMAKE_LINKER)
+
+  else()
+    message(FATAL_ERROR "Mold linker not found")
+  endif()
+endif()