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diff --git a/Help/policy/CMP0083.rst b/Help/policy/CMP0083.rst new file mode 100644 index 0000000..7518ee3 --- /dev/null +++ b/Help/policy/CMP0083.rst @@ -0,0 +1,71 @@ +CMP0083 +------- + +.. versionadded:: 3.14 + +To control generation of Position Independent Executable (``PIE``) or not, some +flags are required at link time. + +CMake 3.13 and lower did not add these link flags when +:prop_tgt:`POSITION_INDEPENDENT_CODE` is set. + +The ``OLD`` behavior for this policy is to not manage ``PIE`` link flags. The +``NEW`` behavior is to add link flags if :prop_tgt:`POSITION_INDEPENDENT_CODE` +is set: + +* Set to ``TRUE``: flags to produce a position independent executable are + passed to the linker step. For example ``-pie`` for ``GCC``. +* Set to ``FALSE``: flags not to produce a position independent executable are + passed to the linker step. For example ``-no-pie`` for ``GCC``. +* Not set: no flags are passed to the linker step. + +Since a given linker may not support ``PIE`` flags in all environments in +which it is used, it is the project's responsibility to use the +:module:`CheckPIESupported` module to check for support to ensure that the +:prop_tgt:`POSITION_INDEPENDENT_CODE` target property for executables will be +honored at link time. + +This policy was introduced in CMake version 3.14. Use the +:command:`cmake_policy` command to set it to ``OLD`` or ``NEW`` explicitly. +Unlike most policies, CMake version |release| does not warn when this policy is +not set and simply uses ``OLD`` behavior. + +.. Note:: + + Android platform has a special handling of ``PIE`` so it is not required + to use the :module:`CheckPIESupported` module to ensure flags are passed to + the linker. + +.. include:: DEPRECATED.txt + +Examples +^^^^^^^^ + +Behave like CMake 3.13 and do not apply any ``PIE`` flags at link stage. + +.. code-block:: cmake + + cmake_minimum_required(VERSION 3.13) + project(foo) + + # ... + + add_executable(foo ...) + set_property(TARGET foo PROPERTY POSITION_INDEPENDENT_CODE TRUE) + +Use the :module:`CheckPIESupported` module to detect whether ``PIE`` is +supported by the current linker and environment. Apply ``PIE`` flags only +if the linker supports them. + +.. code-block:: cmake + + cmake_minimum_required(VERSION 3.14) # CMP0083 NEW + project(foo) + + include(CheckPIESupported) + check_pie_supported() + + # ... + + add_executable(foo ...) + set_property(TARGET foo PROPERTY POSITION_INDEPENDENT_CODE TRUE) |