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Diffstat (limited to 'Modules/CheckPIESupported.cmake')
| -rw-r--r-- | Modules/CheckPIESupported.cmake | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/Modules/CheckPIESupported.cmake b/Modules/CheckPIESupported.cmake new file mode 100644 index 0000000..720217d --- /dev/null +++ b/Modules/CheckPIESupported.cmake @@ -0,0 +1,134 @@ +# Distributed under the OSI-approved BSD 3-Clause License. See accompanying +# file Copyright.txt or https://cmake.org/licensing for details. + +#[=======================================================================[.rst: +CheckPIESupported +----------------- + +Check whether the linker supports position independent code (PIE) or no +position independent code (NO_PIE) for executables. +Use this to ensure that the :prop_tgt:`POSITION_INDEPENDENT_CODE` target +property for executables will be honored at link time. + +.. command:: check_pie_supported + + :: + + check_pie_supported([OUTPUT_VARIABLE <output>] + [LANGUAGES <lang>...]) + + Options are: + + ``OUTPUT_VARIABLE <output>`` + Set ``<output>`` variable with details about any error. + ``LANGUAGES <lang>...`` + Check the linkers used for each of the specified languages. + Supported languages are ``C``, ``CXX``, and ``Fortran``. + +It makes no sense to use this module when :policy:`CMP0083` is set to ``OLD``, +so the command will return an error in this case. See policy :policy:`CMP0083` +for details. + +Variables +^^^^^^^^^ + +For each language checked, two boolean cache variables are defined. + + ``CMAKE_<lang>_LINK_PIE_SUPPORTED`` + Set to ``YES`` if ``PIE`` is supported by the linker and ``NO`` otherwise. + ``CMAKE_<lang>_LINK_NO_PIE_SUPPORTED`` + Set to ``YES`` if ``NO_PIE`` is supported by the linker and ``NO`` otherwise. + +Examples +^^^^^^^^ + +.. code-block:: cmake + + check_pie_supported() + set_property(TARGET foo PROPERTY POSITION_INDEPENDENT_CODE TRUE) + +.. code-block:: cmake + + # Retrieve any error message. + check_pie_supported(OUTPUT_VARIABLE output LANGUAGES C) + set_property(TARGET foo PROPERTY POSITION_INDEPENDENT_CODE TRUE) + if(NOT CMAKE_C_LINK_PIE_SUPPORTED) + message(WARNING "PIE is not supported at link time: ${output}.\n" + "PIE link options will not be passed to linker.") + endif() + +#]=======================================================================] + + +include (Internal/CMakeCheckCompilerFlag) + +function (check_pie_supported) + cmake_policy(GET CMP0083 cmp0083) + + if (NOT cmp0083) + message(FATAL_ERROR "check_pie_supported: Policy CMP0083 is not set") + endif() + + if(cmp0083 STREQUAL "OLD") + message(FATAL_ERROR "check_pie_supported: Policy CMP0083 set to OLD") + endif() + + set(optional) + set(one OUTPUT_VARIABLE) + set(multiple LANGUAGES) + + cmake_parse_arguments(CHECK_PIE "${optional}" "${one}" "${multiple}" "${ARGN}") + if(CHECK_PIE_UNPARSED_ARGUMENTS) + message(FATAL_ERROR "check_pie_supported: Unparsed arguments: ${CHECK_PIE_UNPARSED_ARGUMENTS}") + endif() + + if (CHECK_PIE_LANGUAGES) + set (unsupported_languages "${CHECK_PIE_LANGUAGES}") + list (REMOVE_ITEM unsupported_languages "C" "CXX" "Fortran") + if(unsupported_languages) + message(FATAL_ERROR "check_pie_supported: language(s) '${unsupported_languages}' not supported") + endif() + else() + # User did not set any languages, use defaults + get_property (enabled_languages GLOBAL PROPERTY ENABLED_LANGUAGES) + if (NOT enabled_languages) + return() + endif() + + list (FILTER enabled_languages INCLUDE REGEX "^(C|CXX|Fortran)$") + if (NOT enabled_languages) + return() + endif() + + set (CHECK_PIE_LANGUAGES ${enabled_languages}) + endif() + + set (outputs) + + foreach(lang IN LISTS CHECK_PIE_LANGUAGES) + if(_CMAKE_${lang}_PIE_MAY_BE_SUPPORTED_BY_LINKER) + cmake_check_compiler_flag(${lang} "${CMAKE_${lang}_LINK_OPTIONS_PIE}" + CMAKE_${lang}_LINK_PIE_SUPPORTED + OUTPUT_VARIABLE output) + if (NOT CMAKE_${lang}_LINK_PIE_SUPPORTED) + string (APPEND outputs "PIE (${lang}): ${output}\n") + endif() + + cmake_check_compiler_flag(${lang} "${CMAKE_${lang}_LINK_OPTIONS_NO_PIE}" + CMAKE_${lang}_LINK_NO_PIE_SUPPORTED + OUTPUT_VARIABLE output) + if (NOT CMAKE_${lang}_LINK_NO_PIE_SUPPORTED) + string (APPEND outputs "NO_PIE (${lang}): ${output}\n") + endif() + else() + # no support at link time. Set cache variables to NO + set(CMAKE_${lang}_LINK_PIE_SUPPORTED NO CACHE INTERNAL "PIE (${lang})") + set(CMAKE_${lang}_LINK_NO_PIE_SUPPORTED NO CACHE INTERNAL "NO_PIE (${lang})") + string (APPEND outputs "PIE and NO_PIE are not supported by linker for ${lang}") + endif() + endforeach() + + if (CHECK_PIE_OUTPUT_VARIABLE) + set (${CHECK_PIE_OUTPUT_VARIABLE} "${outputs}" PARENT_SCOPE) + endif() +endfunction() |