diff options
Diffstat (limited to 'Help')
| -rw-r--r-- | Help/manual/cmake-policies.7.rst | 1 | ||||
| -rw-r--r-- | Help/policy/CMP0123.rst | 32 | ||||
| -rw-r--r-- | Help/release/dev/ARMClang-cpu-arch-flags.rst | 7 |
3 files changed, 40 insertions, 0 deletions
diff --git a/Help/manual/cmake-policies.7.rst b/Help/manual/cmake-policies.7.rst index 5dfa894..b41ce59 100644 --- a/Help/manual/cmake-policies.7.rst +++ b/Help/manual/cmake-policies.7.rst @@ -57,6 +57,7 @@ Policies Introduced by CMake 3.21 .. toctree:: :maxdepth: 1 + CMP0123: ARMClang cpu/arch compile and link flags must be set explicitly. </policy/CMP0123> CMP0122: UseSWIG use standard library name conventions for csharp language. </policy/CMP0122> CMP0121: The list command detects invalid indicies. </policy/CMP0121> diff --git a/Help/policy/CMP0123.rst b/Help/policy/CMP0123.rst new file mode 100644 index 0000000..e09b5ec --- /dev/null +++ b/Help/policy/CMP0123.rst @@ -0,0 +1,32 @@ +CMP0123 +------- + +.. versionadded:: 3.21 + +``ARMClang`` cpu/arch compile and link flags must be set explicitly. + +CMake 3.20 and lower automatically maps the :variable:`CMAKE_SYSTEM_PROCESSOR` +variable and an undocumented ``CMAKE_SYSTEM_ARCH`` to compile and link options +for ``ARMClang``. For example, the ``-mcpu=cortex-m33`` flag is added when +:variable:`CMAKE_SYSTEM_PROCESSOR` equals ``cortex-m33``. CMake requires +projects to set either variable or it raises a fatal error. However, the +project may need to additionally specify CPU features using e.g. +``-mcpu=cortex-m33+nodsp``, conflicting with the ``-mcpu=cortex-m33`` added +by CMake. This results in either link errors or unusable binaries. + +CMake 3.21 and above prefer instead to not add any cpu/arch compile and link +flags automatically. Instead, projects must specify them explicitly. +This policy provides compatibility for projects that have not been updated. + +The ``OLD`` behavior of this policy requires projects that use ``ARMClang`` +to set either :variable:`CMAKE_SYSTEM_PROCESSOR` or ``CMAKE_SYSTEM_ARCH`` +and it automatically adds a compile option ``-mcpu=`` or ``-march=`` and +a link option ``--cpu=`` based on those variables. The ``NEW`` behavior +does not add compile or link options, and projects are responsible for +setting correct options. + +This policy was introduced in CMake version 3.21. CMake version |release| +warns when the policy is not set and uses ``OLD`` behavior. Use the +:command:`cmake_policy` command to set it to ``OLD`` or ``NEW`` explicitly. + +.. include:: DEPRECATED.txt diff --git a/Help/release/dev/ARMClang-cpu-arch-flags.rst b/Help/release/dev/ARMClang-cpu-arch-flags.rst new file mode 100644 index 0000000..5e885fe --- /dev/null +++ b/Help/release/dev/ARMClang-cpu-arch-flags.rst @@ -0,0 +1,7 @@ +ARMClang-cpu-arch-flags +----------------------- + +* ``ARMClang`` cpu/arch compile and link flags are no longer added + automatically based on the :variable:`CMAKE_SYSTEM_PROCESSOR` + variable or the undocumented ``CMAKE_SYSTEM_ARCH`` variable. + They must be specified explicitly. See policy :policy:`CMP0123`. |