CheckPIESupported

New in version 3.14.

This module provides a command to check whether the linker supports Position Independent Code (PIE) or No Position Independent Code (NO_PIE) for executables.

Load this module in a CMake project with:

include(CheckPIESupported)

When setting the POSITION_INDEPENDENT_CODE target property, PIC-related compile and link options are added when building library objects, and PIE-related compile options are added when building objects of executable targets, regardless of this module. Use this module to ensure that the POSITION_INDEPENDENT_CODE target property for executables is also honored at link time.

Commands

This module provides the following command:

check_pie_supported

Checks for PIE/NO_PIE support and prepares all executables to have link time PIE options enabled:

check_pie_supported([OUTPUT_VARIABLE <output>] [LANGUAGES <langs>...])

Options are:

OUTPUT_VARIABLE <output>

Set <output> variable with details about any error. If the check is bypassed because it uses cached results from a previous call, the output will be empty even if errors were present in the previous call.

LANGUAGES <langs>...

Check the linkers used for each of the specified languages. If this option is not provided, the command checks all enabled languages.

C, CXX, Fortran are supported.

New in version 3.23: OBJC, OBJCXX, CUDA, and HIP are supported.

Note

To use check_pie_supported(), policy CMP0083 must be set to NEW; otherwise, a fatal error will occur.

Variables

For each language checked, the check_pie_supported() command defines two boolean cache variables:

CMAKE_<lang>_LINK_PIE_SUPPORTED

Set to true if PIE is supported by the linker and false otherwise.

CMAKE_<lang>_LINK_NO_PIE_SUPPORTED

Set to true if NO_PIE is supported by the linker and false otherwise.

Examples

To enable PIE on an executable target at link time as well, include this module and call check_pie_supported() before setting the POSITION_INDEPENDENT_CODE target property. This will determine whether the linker for each checked language supports PIE-related link options. For example:

add_executable(foo ...)

include(CheckPIESupported)
check_pie_supported()
set_property(TARGET foo PROPERTY POSITION_INDEPENDENT_CODE TRUE)

Since not all linkers require or support PIE-related link options (for example, MSVC), retrieving any error messages might be useful for logging purposes:

add_executable(foo ...)

message(CHECK_START "Checking for C linker PIE support")

include(CheckPIESupported)
check_pie_supported(OUTPUT_VARIABLE output LANGUAGES C)
set_property(TARGET foo PROPERTY POSITION_INDEPENDENT_CODE TRUE)

if(CMAKE_C_LINK_PIE_SUPPORTED)
  message(CHECK_PASS "yes")
else()
  message(CHECK_FAIL "no")
  message(VERBOSE "PIE is not supported at link time:\n${output}"
                  "PIE link options will not be passed to linker.")
endif()

Setting the POSITION_INDEPENDENT_CODE target property on an executable without this module will set PIE-related compile options but not PIE-related link options, which might not be sufficient in certain cases:

add_executable(foo ...)
set_property(TARGET foo PROPERTY POSITION_INDEPENDENT_CODE TRUE)