In order to ease maintenance and enable faster development in the OpenCL headers, the OpenCL headers for extensions are generated from the OpenCL XML machine readable grammar. Currently, header generation is only enabled for the OpenCL headers for extensions, and the OpenCL headers for core APIs are still authored manually.
The OpenCL headers are generated using Python Mako Templates.
In most cases, after installing Python for your platform, Mako may be installed using:
$ pip install Mako
Most changes only require modifications to the Mako templates. Small changes modifying syntax or layout are simple and straightforward. Occasionally, more complicated changes will be required, say when a new API is added that is unlike any previous API or when a new extension header file is needed, but this should be rare.
The Python script should only need to be modified if additional information needs to be propagated from the XML file into the Mako template itself.
The script to generate headers requires the cl.xml machine readable grammar. The latest version of cl.xml may be found in the Khronos OpenCL-Docs repo here.
The easiest way to generate new headers is by using the headers_generate target. For example, from a directory used to build the headers, simply execute:
$ cmake --build . --target headers_generate
The cl.xml file used to generate headers with the header generation target may be provided by setting the CMake variable OPENCL_HEADERS_XML_PATH to the full path to cl.xml.