llvm-project/compiler-rt/cmake/Modules/CompilerRTMockLLVMCMakeConf...

76 lines
3.0 KiB
CMake

# This macro mocks enough of the changes `LLVMConfig.cmake` makes so that
# compiler-rt can successfully configure itself when a LLVM toolchain is
# available but the corresponding CMake build files are not.
#
# The motivation for this is to be able to generate the compiler-rt
# lit tests suites and run them against an arbitrary LLVM toolchain
# which doesn't ship the LLVM CMake build files.
macro(compiler_rt_mock_llvm_cmake_config)
message(STATUS "Attempting to mock the changes made by LLVMConfig.cmake")
compiler_rt_mock_llvm_cmake_config_set_cmake_path()
compiler_rt_mock_llvm_cmake_config_set_target_triple()
compiler_rt_mock_llvm_cmake_config_include_cmake_files()
endmacro()
macro(compiler_rt_mock_llvm_cmake_config_set_cmake_path)
# Point `LLVM_CMAKE_DIR` at the source tree in the monorepo.
set(LLVM_CMAKE_DIR "${LLVM_MAIN_SRC_DIR}/cmake/modules")
if (NOT EXISTS "${LLVM_CMAKE_DIR}")
message(FATAL_ERROR "LLVM_CMAKE_DIR (${LLVM_CMAKE_DIR}) does not exist")
endif()
list(APPEND CMAKE_MODULE_PATH "${LLVM_CMAKE_DIR}")
message(STATUS "LLVM_CMAKE_DIR: \"${LLVM_CMAKE_DIR}\"")
endmacro()
function(compiler_rt_mock_llvm_cmake_config_set_target_triple)
# Various bits of compiler-rt depend on the `TARGET_TRIPLE`variable being
# defined. This function tries to set a sensible value for the variable.
# This is a function rather than a macro to avoid polluting the variable
# namespace.
set(COMPILER_OUTPUT "")
# If the user provides `COMPILER_RT_DEFAULT_TARGET_ONLY` and `CMAKE_C_COMPILER_TARGET`
# (see `construct_compiler_rt_default_triple`) then prefer that to examining the
# compiler.
if (COMPILER_RT_DEFAULT_TARGET_ONLY)
if (NOT "${CMAKE_C_COMPILER_TARGET}" STREQUAL "")
message(STATUS
"Using CMAKE_C_COMPILER_TARGET (${CMAKE_C_COMPILER_TARGET}) as TARGET_TRIPLE")
endif()
set(COMPILER_OUTPUT "${CMAKE_C_COMPILER_TARGET}")
endif()
# Try asking the compiler for its default target triple.
set(HAD_ERROR FALSE)
if ("${COMPILER_OUTPUT}" STREQUAL "")
if ("${CMAKE_C_COMPILER_ID}" MATCHES "Clang|GNU")
# Note: Clang also supports `-print-target-triple` but gcc doesn't
# support this flag.
execute_process(
COMMAND "${CMAKE_C_COMPILER}" -dumpmachine
RESULT_VARIABLE HAD_ERROR
OUTPUT_VARIABLE COMPILER_OUTPUT
OUTPUT_STRIP_TRAILING_WHITESPACE)
else()
message(FATAL_ERROR
"Fetching target triple from compiler \"${CMAKE_C_COMPILER_ID}\" "
"is not implemented.")
endif()
endif()
if (HAD_ERROR)
message(FATAL_ERROR "Fetching target triple from compiler failed")
endif()
set(TARGET_TRIPLE "${COMPILER_OUTPUT}")
message(STATUS "TARGET_TRIPLE: \"${TARGET_TRIPLE}\"")
if ("${TARGET_TRIPLE}" STREQUAL "")
message(FATAL_ERROR "TARGET_TRIPLE cannot be empty")
endif()
set(TARGET_TRIPLE "${TARGET_TRIPLE}" PARENT_SCOPE)
endfunction()
macro(compiler_rt_mock_llvm_cmake_config_include_cmake_files)
# Some compiler-rt CMake code needs to call code in this file.
include("${LLVM_CMAKE_DIR}/AddLLVM.cmake")
endmacro()