CUDA: Add CUDA_ARCHITECTURES target property

Simplifies CUDA target architecture handling.

Required for Clang support as Clang doesn't automatically select a supported architecture.
We detect a supported architecture during compiler identification and set CMAKE_CUDA_ARCHITECTURES to it.

Introduces CMP0104 for backwards compatibility with manually setting code generation flags with NVCC.

Implements #17963.

1 files changed, 30 insertions, 0 deletions

diff --git a/Help/prop_tgt/CUDA_ARCHITECTURES.rst b/Help/prop_tgt/CUDA_ARCHITECTURES.rst
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+CUDA_ARCHITECTURES
+------------------
+
+List of architectures to generate device code for.
+
+An architecture can be suffixed by either ``-real`` or ``-virtual`` to specify
+the kind of architecture to generate code for.
+If no suffix is given then code is generated for both real and virtual
+architectures.
+
+This property is initialized by the value of the :variable:`CMAKE_CUDA_ARCHITECTURES`
+variable if it is set when a target is created.
+
+The ``CUDA_ARCHITECTURES`` target property must be set to a non-empty value on targets
+that compile CUDA sources, or it is an error.  See policy :policy:`CMP0104`.
+
+Examples
+^^^^^^^^
+
+.. code-block:: cmake
+
+  set_property(TARGET tgt PROPERTY CUDA_ARCHITECTURES 35 50 72)
+
+Generates code for real and virtual architectures ``30``, ``50`` and ``72``.
+
+.. code-block:: cmake
+
+  set_property(TARGET tgt PROPERTY CUDA_ARCHITECTURES 70-real 72-virtual)
+
+Generates code for real architecture ``70`` and virtual architecture ``72``.