[cfe-dev] [RFC][OpenCL] Allow users to add supported OpenCL extensions by pragma

[Anastasia Stulova via cfe-dev]

Interesting idea! Just to be clear, you are suggesting to add parsing of the following into Clang:

#pragma OPENCL EXTENSION the_new_extension_name : register

Which would add custom the_new_extension_name to the list of known and supported OpenCL extensions dynamically?

Normally, target triple that combines RT and specific hardware type would be used for those purposes.
But I believe it shouldn't be too complicated to add this pragma considering that OpenCL already has similar ones.

This approach could offer some degree of flexibility to the library implementations,
which would otherwise have to add separate triple representing their library ABIs.

Would this be allowed in any OpenCL code as some sort of Clang extension or is there a plan to add this into Spec?

Thanks,
Anastasia
From: Liu, Yaxun (Sam) [mailto:Yaxun.Liu at amd.com]
Sent: 10 June 2016 19:40
To: cfe-dev (cfe-dev at lists.llvm.org); Anastasia Stulova; Bader, Alexey (alexey.bader at intel.com); Pan, Xiuli
Cc: Sumner, Brian; Jeroen Ketema
Subject: [RFC][OpenCL] Allow users to add supported OpenCL extensions by pragma

Currently Clang defines supported OpenCL extensions for each target based on triple and CPU. As a default configuration this seems sufficient.

However if vendors and library developers want to add support of their own extensions, they have to modify Clang, which is very inconvenient.

We need a flexible and expressive way to add supported extensions for vendors and library developers.

Brian has a proposal which introduces a pragma to add supported extensions:

#pragma OPENCL EXTENSION the_new_extension_name : register

This pragma tells clang the name of a new OpenCL extension and request that it process it just like any other OpenCL extension, e.g. recognize

#pragma OPENCL EXTENSION the_new_extension_name : enable/disable

in subsequent code.

Since this pragma can be used in the header file of vendors or library developers' OpenCL implementations, it can provide flexible and expressive way to represent supported extensions when combined with other preprocessor constructs.

Any feedbacks? Thanks.

Sam



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