Back in December I wrote about the proper Radeon Gallium3D shader disassembler. "For aiding in the debugging process and for improving the Radeon Gallium3D driver with regard to shader optimizations, Vadim Girlin is looking to have a shader disassembler within the driver itself. Adding the disassembler to the Gallium3D driver is small and is only used when an environment variable is set, but adding the ISA information tables is what makes the work large due to all of the data about the different possible shader instructions."
After going through three revisions, Vadim Girlin's shader disassembler for R600g was merged into mainline Mesa today per this commit.
For those wanting to toy with this new feature, the R600_DUMP_SHADERS environment variable controls the new functionality.