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JojoS62JojoS62
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add custom linker script (#103)
* add custom linker script a custom linker script can be applied by adding the .ld filepath as 2nd argument to mbed_set_post_build * more detailed comment * add if is_standalone for text cases * replace COMMENT in add_custom_command by echo COMMENT is not reliable printed
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‎tools/cmake/mbed_set_linker_script.cmake

Lines changed: 64 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -56,6 +56,8 @@ function(mbed_setup_linker_script mbed_os_target mbed_baremetal_target target_de
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OUTPUT
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${LINKER_SCRIPT_PATH}
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PRE_LINK
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COMMAND
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${CMAKE_COMMAND} -E echo "Preprocess linker script: ${RAW_LINKER_SCRIPT_NAME} -> ${LINKER_SCRIPT_NAME}"
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COMMAND
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${CMAKE_C_COMPILER} @${linker_defs_response_file}
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-E -x assembler-with-cpp
@@ -68,23 +70,80 @@ function(mbed_setup_linker_script mbed_os_target mbed_baremetal_target target_de
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${target_defines_header}
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WORKING_DIRECTORY
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${CMAKE_CURRENT_SOURCE_DIR}
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COMMENT
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"Preprocess linker script: ${RAW_LINKER_SCRIPT_NAME} -> ${LINKER_SCRIPT_NAME}"
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VERBATIM
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)
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# The job to create the linker script gets attached to the mbed-linker-script target,
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# which is then added as a dependency of the MCU target. This ensures the linker script will exist
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# by the time we need it.
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add_custom_target(mbed-linker-script DEPENDS ${LINKER_SCRIPT_PATH} VERBATIM)
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foreach(TARGET ${mbed_baremetal_target} ${mbed_os_target})
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add_dependencies(${TARGET} mbed-linker-script)
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# Add linker flags to the MCU target to pick up the preprocessed linker script
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target_link_options(${TARGET}
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# When building the Mbed internal tests, the tests get created before the mbed-os target does. So, the normal logic
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# in mbed_set_post_build() to set the linker script does not work. So, we need to instead attach the linker script to
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# the mbed-os and mbed-baremetal libraries themselves, so it will get picked up automatically.
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# This prevents a custom linker script from being used in STANDALONE mode, but we don't need to do that.
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set_target_properties(${TARGET} PROPERTIES LINKER_SCRIPT_PATH ${LINKER_SCRIPT_PATH})
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# add linker script only for tests
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if(MBED_IS_STANDALONE)
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target_link_options(${TARGET}
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INTERFACE
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"-T" "${LINKER_SCRIPT_PATH}"
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)
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)
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endif()
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endforeach()
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endfunction(mbed_setup_linker_script)
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#
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# Change the linker script to a custom supplied script instead of the built in.
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# this function is called by mbed_set_post_build(target linker_script)
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#
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# target: CMake target for Mbed OS
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# new_linker_script_path: raw linker script
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#
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function(mbed_set_custom_linker_script target new_linker_script_path)
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set(RAW_LINKER_SCRIPT_PATHS ${CMAKE_CURRENT_SOURCE_DIR}/${new_linker_script_path})
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set(CUSTOM_LINKER_SCRIPT_PATH ${CMAKE_CURRENT_BINARY_DIR}/${target}.link_spript.ld)
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# To avoid path limits on Windows, we create a "response file" and set the path to it as a
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# global property. We need this solely to pass the compile definitions to GCC's preprocessor,
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# so it can expand any macro definitions in the linker script.
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get_property(linker_defs_response_file GLOBAL PROPERTY COMPILE_DEFS_RESPONSE_FILE)
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get_filename_component(RAW_LINKER_SCRIPT_NAME ${RAW_LINKER_SCRIPT_PATHS} NAME)
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get_filename_component(LINKER_SCRIPT_NAME ${CUSTOM_LINKER_SCRIPT_PATH} NAME)
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add_custom_command(
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TARGET
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${target}
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PRE_LINK
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COMMAND
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${CMAKE_COMMAND} -E echo "Preprocess custom linker script: ${RAW_LINKER_SCRIPT_NAME} -> ${LINKER_SCRIPT_NAME}"
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COMMAND
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${CMAKE_C_COMPILER} @${linker_defs_response_file}
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-E -x assembler-with-cpp
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-include ${CMAKE_BINARY_DIR}/mbed-os/mbed-target-config.h
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-P ${RAW_LINKER_SCRIPT_PATHS}
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-o ${CUSTOM_LINKER_SCRIPT_PATH}
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DEPENDS
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${RAW_LINKER_SCRIPT_PATHS}
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${linker_defs_response_file}
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${target_defines_header}
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WORKING_DIRECTORY
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${CMAKE_CURRENT_SOURCE_DIR}
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VERBATIM
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)
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# Add linker flags to the target to pick up the preprocessed linker script
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target_link_options(${target}
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PRIVATE
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"-T" "${CUSTOM_LINKER_SCRIPT_PATH}"
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)
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endfunction(mbed_set_custom_linker_script)

‎tools/cmake/mbed_target_functions.cmake

Lines changed: 25 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -126,7 +126,32 @@ endfunction()
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#
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# Set post build operations
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#
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# target: the affected target
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# 2nd arg: optional, linker script path
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#
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function(mbed_set_post_build target)
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# add linker script. Skip for greentea test code, there the linker script is set in mbed_setup_linker_script()
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if (NOT MBED_IS_STANDALONE)
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if("${ARGN}" STREQUAL "")
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if(TARGET mbed-os)
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get_target_property(LINKER_SCRIPT_PATH mbed-os LINKER_SCRIPT_PATH)
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target_link_options(${target}
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PRIVATE
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"-T" "${LINKER_SCRIPT_PATH}"
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)
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elseif(TARGET mbed-baremetal)
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get_target_property(LINKER_SCRIPT_PATH mbed-baremetal LINKER_SCRIPT_PATH)
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target_link_options(${target}
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PRIVATE
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"-T" "${LINKER_SCRIPT_PATH}"
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)
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endif()
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else()
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message(STATUS "${target} uses custom linker script ${ARGV2}")
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mbed_set_custom_linker_script(${target} ${ARGV2})
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endif()
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endif()
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# The mapfile name includes the top-level target name and the
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# executable suffix for all toolchains as CMake hardcodes the name of the
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# diagnostic output file for some toolchains.

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