Intel Iris Gallium3D Is Close With SPIR-V Support For OpenGL 4.6

This week saw OpenGL 4.6 support finally merged for Intel's i965 Mesa driver and will be part of the upcoming Mesa 19.2 release. Not landed yet but coming soon is the newer Intel "Iris" Gallium3D driver also seeing OpenGL 4.6 support.

Iris Gallium3D has been at OpenGL 4.5 support and is quite near as well with its OpenGL 4.6 support thanks to the shared NIR support and more with the rest of the Intel open-source graphics stack. Though it's looking less likely that OpenGL 4.6 support would be back-ported to Mesa 19.2 for Iris, but we'll see.

This merge request is for the Iris SPIR-V support as the remaining extensions needed for getting OpenGL 4.6 support in place with this new Intel Gallium3D driver. It's looking like once the new patches are properly tested that this support could be merged into Mesa Git.

Intel Gallium3D overall is in quite good shape and the performance is almost beating out their former driver across the board. By Mesa 19.3 the Gallium3D driver should become the default for Intel Broadwell graphics and newer. With Tigerlake "Gen 12" graphics is also the first where the OpenGL support will only be implemented along the Gallium3D driver where as with Gen 11 Icelake graphics there is support in both drivers but the Gallium3D driver should ultimately be the better solution moving forward.