Some two years ago there was a branch of Mesa created by Zack Rusin named "Clover" with intentions of providing OpenCL over Mesa
. While it looked hopeful at first, this code to support OpenCL over
Mesa was never finished and after a while it didn't receive any further work. It's been months since there's been much activity in this area of GPGPU support for Mesa/Gallium3D, but recently Zack has renewed his interest in getting Mesa Clover working.
There's been barely any activity on the Mesa Clover branch
aside from a few commits early in the year, but this month there's been quite a few commits by Zack on this OpenCL branch. Mesa Clover now has the updated OpenCL header files, the CPU winsys has been dropped, more of the API is implemented as stub functions, and this LLVM Clang-powered OpenCL compiler for Gallium3D is closer to being "reasonable" according to Zack.
The Mesa/Gallium3D OpenCL implementation that leverages LLVM still is far from being ready for mainline integration or properly supporting the OpenCL 1.0/1.1 specifications, but at least there is finally new activity going on in this area of compute support.