Getting OpenCL program code from GPU

Question

I have program which use OpenCL do do math, how i can get source code of opencl, that execute on my gpu when this program do calculations?

Answer 1

The most straightforward approach is to look for the kernel string in the application. Sometimes you'll be able to just find its source lying in some .cl file, otherwise you can try to scan the application's binaries with something like strings. If the application is not purposefully obfuscating the kernel source, you're likely to find it using one of those methods.

A more bulletproof approach would be to catch the strings provided to the OpenCL API. You can even provide your own OpenCL implementation that just prints out the kernel strings in the relevant cl function. It's actually pretty easy: start with pocl and change the implementation of clCreateProgramWithSource to print out the input strings - this is a trivial code change.

You can then install that modified version as an OpenCL implementation and make sure the application uses it. This might be tricky if the application requires certain OpenCL capabilities, but your implementation can of course lie about those.

Notice that in the future, SPIR can make this sort of thing impossible - you'll be able to get an IR of the kernel, but not its source.

Answer 2

clGetProgramInfo(..., CL_PROGRAM_BINARIES, ...) gets you the compiled binary, but interpreting that is dependent upon the architecture. Various SDK's have different tools that might get you GPU assembly though.