0274bcbee4
Newlib or Picolibc libraries for LLVM may be compiled or installed from pre-built sources independently of LLVM itself. This means that always indicating that TOOLCHAIN_HAS_NEWLIB=OFF and TOOLCHAIN_HAS_PICOLIBC=OFF are wrong. But it could be just as wrong to always indicate suport for newlib or picolibc. Some pre-built LLVM toolchains are provided with default picolibc support, such as LLVM for Arm embedded, but can also be used with newlib be installing newlib add-on package. Unfortunately it's not possible to query LLVM regarding newlib or picolibc support. Developers have the option of `-DTOOLCHAIN_HAS_<NEWLIB|PICOLIBC>=ON`, but this is not widely known and cumbersome to do for each build. An indication of newlib or picolibc support is the presence of library specific headers, so to improve current situation we check for library specific headers, and if those are present we assume support for the library. This commit improves the current support for LLVM in Zephyr when cross-compiling, especially for users of LLVM for Arm embedded. Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
121 lines
4.2 KiB
CMake
121 lines
4.2 KiB
CMake
# SPDX-License-Identifier: Apache-2.0
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# Configuration for host installed clang
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#
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set(NOSTDINC "")
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# Note that NOSYSDEF_CFLAG may be an empty string, and
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# set_ifndef() does not work with empty string.
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if(NOT DEFINED NOSYSDEF_CFLAG)
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set(NOSYSDEF_CFLAG -undef)
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endif()
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if(DEFINED TOOLCHAIN_HOME)
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set(find_program_clang_args PATHS ${TOOLCHAIN_HOME} NO_DEFAULT_PATH)
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endif()
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find_program(CMAKE_C_COMPILER clang ${find_program_clang_args})
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find_program(CMAKE_CXX_COMPILER clang++ ${find_program_clang_args})
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if(NOT "${ARCH}" STREQUAL "posix")
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include(${ZEPHYR_BASE}/cmake/gcc-m-cpu.cmake)
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include(${ZEPHYR_BASE}/cmake/gcc-m-fpu.cmake)
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if("${ARCH}" STREQUAL "arm")
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list(APPEND TOOLCHAIN_C_FLAGS
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-fshort-enums
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)
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list(APPEND TOOLCHAIN_LD_FLAGS
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-fshort-enums
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)
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include(${ZEPHYR_BASE}/cmake/compiler/clang/target_arm.cmake)
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elseif("${ARCH}" STREQUAL "arm64")
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include(${ZEPHYR_BASE}/cmake/compiler/clang/target_arm64.cmake)
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elseif("${ARCH}" STREQUAL "riscv")
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include(${ZEPHYR_BASE}/cmake/compiler/gcc/target_riscv.cmake)
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endif()
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if(DEFINED CMAKE_C_COMPILER_TARGET)
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set(clang_target_flag "--target=${CMAKE_C_COMPILER_TARGET}")
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endif()
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foreach(file_name include/stddef.h)
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execute_process(
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COMMAND ${CMAKE_C_COMPILER} --print-file-name=${file_name}
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OUTPUT_VARIABLE _OUTPUT
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)
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get_filename_component(_OUTPUT "${_OUTPUT}" DIRECTORY)
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string(REGEX REPLACE "\n" "" _OUTPUT ${_OUTPUT})
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list(APPEND NOSTDINC ${_OUTPUT})
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endforeach()
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foreach(isystem_include_dir ${NOSTDINC})
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list(APPEND isystem_include_flags -isystem "\"${isystem_include_dir}\"")
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endforeach()
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if(CONFIG_X86)
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if(CONFIG_64BIT)
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list(APPEND TOOLCHAIN_C_FLAGS "-m64")
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else()
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list(APPEND TOOLCHAIN_C_FLAGS "-m32")
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endif()
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endif()
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# LLVM will use a default sysroot for selection of the C library. The default
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# C library sysroot was defined at built time of clang/LLVM.
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#
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# For example, LLVM for Arm comes pre-built with Picolibc, and thus no flags
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# are required for selecting Picolibc.
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#
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# Other clang/LLVM distributions may come with other pre-built C libraries.
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# clang/LLVM supports using an alternative C library, either by direct linking,
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# or by specifying '--sysroot <path>'.
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#
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# LLVM for Arm provides a 'newlib.cfg' file for newlib C selection.
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# Let us support this principle by looking for a dedicated 'newlib.cfg' or
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# 'picolibc.cfg' and specify '--config <spec>.cfg' if such a file is found.
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# If no cfg-file matching the chosen C implementation, then we assume that the
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# chosen C implementation is identical to the default C library used be the
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# toolchain.
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if(CONFIG_NEWLIB_LIBC)
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file(GLOB_RECURSE newlib_cfg ${LLVM_TOOLCHAIN_PATH}/newlib.cfg)
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if(newlib_cfg)
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list(GET newlib_cfg 0 newlib_cfg)
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set_linker_property(PROPERTY c_library "--config=${newlib_cfg};-lc")
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list(APPEND CMAKE_REQUIRED_FLAGS --config=${newlib_cfg})
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list(APPEND TOOLCHAIN_C_FLAGS --config=${newlib_cfg})
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endif()
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endif()
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if(CONFIG_PICOLIBC)
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file(GLOB_RECURSE picolibc_cfg ${LLVM_TOOLCHAIN_PATH}/picolibc.cfg)
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if(picolibc_cfg)
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list(GET picolibc_cfg 0 picolibc_cfg)
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set_linker_property(PROPERTY c_library "--config=${picolibc_cfg};-lc")
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list(APPEND CMAKE_REQUIRED_FLAGS --config=${picolibc_cfg})
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list(APPEND TOOLCHAIN_C_FLAGS --config=${picolibc_cfg})
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endif()
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endif()
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# This libgcc code is partially duplicated in compiler/*/target.cmake
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execute_process(
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COMMAND ${CMAKE_C_COMPILER} ${clang_target_flag} ${TOOLCHAIN_C_FLAGS}
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--print-libgcc-file-name
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OUTPUT_VARIABLE RTLIB_FILE_NAME
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OUTPUT_STRIP_TRAILING_WHITESPACE
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)
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get_filename_component(RTLIB_DIR ${RTLIB_FILE_NAME} DIRECTORY)
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get_filename_component(RTLIB_NAME_WITH_PREFIX ${RTLIB_FILE_NAME} NAME_WLE)
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string(REPLACE lib "" RTLIB_NAME ${RTLIB_NAME_WITH_PREFIX})
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set_property(TARGET linker PROPERTY lib_include_dir "-L${RTLIB_DIR}")
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set_property(TARGET linker PROPERTY rt_library "-l${RTLIB_NAME}")
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list(APPEND CMAKE_REQUIRED_FLAGS -nostartfiles -nostdlib ${isystem_include_flags})
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string(REPLACE ";" " " CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS}")
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endif()
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