How to find the exectly asm kernel code when enabling SYCL?

[TJU-PanYizhe]

How to find the exectly asm kernel code when enabling SYCL?
I compiled the code using -fsycl to with SYCL support into the asm format(a .s file)
How to find the exectly asm kernel code in that asm file?
When I use this project to compile source code to executable on my RISC-V machine, How could I know if the compiler uses any RISC-V Extensions to improve the proformance of the SYCL kernel, like RISC-V Vector Extension?

[AlexeySachkov]

Hi @TJU-PanYizhe,

I compiled the code using -fsycl to with SYCL support into the asm format(a .s file)
How to find the exectly asm kernel code in that asm file?

I'm not sure how our compiler driver behaves in this scenario (maybe @mdtoguchi knows), but my assumption is that there will be no device code in that .s file.

When only -fsycl is specified, device code is compiled down to SPIR-V and then embedded into the application as a global constant. It is not compiled down to host system assembly, because it is not directly executable. Instead, it undergoes JIT compilation for a selected device at runtime. That is done via low-level runtimes like OpenCL or Level Zero.

Please refer to documentation for OpenCL implementation for your HW to see what options they provide for extracting assembly out of OpenCL programs.

[TJU-PanYizhe]

Thanks a lot!

[mdtoguchi]

When creating an assembly file (assuming using -fsycl -S) the resulting file is considered a 'fat' assembly file. This contains 2 sections: 1) assembly host code 2) device code represented as LLVM-IR. Using the clang-offload-bundler tool you can extract these generated sections. You can find more information about that tool here: https://clang.llvm.org/docs/ClangOffloadBundler.html

[TJU-PanYizhe]

Thanks a lot!