[SYCL] Support for cross-compilation?

[kpet]

A quick look at the code suggests that cross-compiling SYCL apps isn't currently possible. Is there any plan to add support? x86->ARM would be particularly interesting.

[bader]

I think it's possible in theory even today, but it's not tested.
What particular problems you see if you target ARM with the clang built from the sycl branch?

Another option: you can try separate compilation as mentioned as # 2 here: https://github.com/intel/llvm/blob/sycl/sycl/doc/GetStartedWithSYCLCompiler.md#build-and-test-a-simple-sycl-program. It splits the compilation into two steps: device part + host part.
Device part emits target agnostic SPIR-V and you can try C++11 compiler for ARM to compile host part of the application.
You can even try to create a fat binary, but it will take much more efforts: you can find "steps" you will have to manually reproduce in the driver test - https://github.com/intel/llvm/blob/sycl/clang/test/Driver/sycl-offload.c.