[SYCL] Avoid infinite loop when kernel fails to compile with memory error

[VerenaBeckham]

The runtime tries to build a kernel again if compilation fails. But if UR returns a memory error the attempt counter was not compared against the maximum number of attempts, so the compiler was continuously called and eventually the loop counter would have overflowed.

[maarquitos14]

@VerenaBeckham is it possible to add a test that would fail without your patch and work after your patch?

[VerenaBeckham]

@VerenaBeckham is it possible to add a test that would fail without your patch and work after your patch?

I'm not sure. Even if you could write a test that allocates so much memory that it runs out, this test might still pass on a different architecture with more memory. Or do you know of a way to mock up this error?

[maarquitos14]

@VerenaBeckham is it possible to add a test that would fail without your patch and work after your patch?

I'm not sure. Even if you could write a test that allocates so much memory that it runs out, this test might still pass on a different architecture with more memory. Or do you know of a way to mock up this error?

I think a unit test with UrMock should do the trick for that: https://github.com/intel/llvm/blob/b437083ea7b827ea6798e3fcfae1fe0f926d1d6d/sycl/doc/developer/ContributeToDPCPP.md#dpc-headers-and-runtime-tests

You can find examples if you grep UrMock within sycl/unittests. Basically, UrMock allows you to redefine the behavior of any UR function for a given test, so you could redefine the function that is triggering the memory error to always return a memory error without even trying to allocate.

[VerenaBeckham]

@VerenaBeckham is it possible to add a test that would fail without your patch and work after your patch?

I'm not sure. Even if you could write a test that allocates so much memory that it runs out, this test might still pass on a different architecture with more memory. Or do you know of a way to mock up this error?

I think a unit test with UrMock should do the trick for that: https://github.com/intel/llvm/blob/b437083ea7b827ea6798e3fcfae1fe0f926d1d6d/sycl/doc/developer/ContributeToDPCPP.md#dpc-headers-and-runtime-tests

You can find examples if you grep UrMock within sycl/unittests. Basically, UrMock allows you to redefine the behavior of any UR function for a given test, so you could redefine the function that is triggering the memory error to always return a memory error without even trying to allocate.

Thanks for the hint! I have added a test.

[maarquitos14]

Just a couple of nits related to LLVM Coding Style, otherwise LGTM.

[VerenaBeckham]

If you're happy with this @maarquitos14 do you want to "approve the workflows" and kick off the testing?

[VerenaBeckham]

I'm sorry, I forgot to push my clang format fixes. 🤦 Fixed now.