VK_KHR_shader_constant_data.proposal

This extension allows applications to specify large constant data arrays in their shaders, and to specialize them.

Problem Statement

SPV_KHR_constant_data added the capability to specify arrayed data as constants in SPIR-V, to enable the specification of strings as data, or other chunks of data, in a more compact manner than previously available. A detailed problem statement on why this was added to SPIR-V is provided in the SPV_KHR_constant_data specification.

Support for this extension is required in Vulkan to add better string support to Vulkan, and particularly for VK_KHR_shader_abort.

Solution Space

For the most part, exposing this extension is as trivial as most other SPIR-V extensions. Despite specialization constant data being new in SPIR-V, the Vulkan specialization constant API already supports constants of arbitrary size, as long as they match the size of the data in SPIR-V.

Proposal

The only change to the Vulkan API is to enable shaders using the SPV_KHR_constant_data extension.