Exposed LLVM symbols

[Naghasan]

Not sure this is the right place for this issue.

We enabled a kernel fusion extension in SYCL (intel/llvm), and for that purpose we have to pull some LLVM libraries in libsycl.so. By doing so, we started to see failure with the Intel GPU driver intel/llvm#7831 (comment).

It seems that the libraries don't isolate themselves from the users causing the user LLVM symbols to be picked up rather than the one it is shipped with.

We internalized the symbols on our side and that solved the issue. However, a build with shared libraries of the project no longer works with this driver and I assume any application using LLVM and this driver would face similar issues.

[mnaczk]

Thank you, @Naghasan, for raising the issue. Would it be possible for you to create a reproducible example where an application that utilizes LLVM encounters conflicts when operating with our driver?

[chengjunlu]

We met the same issue in Triton.

[kurapov-peter]

Hi! We encounter a similar issue from time to time while building a library that has LLVM as its dependency and submits kernels to IGC via level zero.

[Naghasan]

Hi @mnaczk, sorry for some reason I missed the notification.

With tip intel/llvm, you should be able to reproduce via this setup (sorry, that's going to be a bit long to build)

$ python3 <path to intel/llvm>/buildbot/configure.py --cmake-opt="-DSYCL_TEST_E2E_TARGETS=level_zero:gpu;opencl:gpu" -s <path to intel/llvm> -o <path to build folder> -t Release --shared-libs
$ cd <path to build folder>
$ ninja sycl-toolchain
$ llvm-lit <path to build folder>/tools/sycl/test-e2e/ -a --param sycl_be=opencl --param target_devices=gpu --filter KernelFusion

You should see failure when build with --shared-libs, but should pass if you don't provide the flag (if you want to build both consider adding --cmake-opt="-DCMAKE_C_COMPILER_LAUNCHER=ccache" --cmake-opt="-DCMAKE_CXX_COMPILER_LAUNCHER=ccache" to the config script).

If the lit command doesn't work, you could simply try this (much longer though as it runs every tests...)

$ ninja check-sycl-e2e

[etiotto]

This issue is unassigned and has been exposed by various project which rely on IGC. Is there any way a fix can be prioritized ?

[pszymich]

Hi, fixed in cf0dd6b
Thanks @MichalMroz12 for the fix!

[sommerlukas]

@pszymich Has this change landed in releases?

It seems that the changed from cf0dd6b were reverted in ee6f20a again.

Also, nm on libigc from version 1.0.16510.2 still seems to show quite a lot of LLVM symbols being exported.

[pjaaskel]

I also encounter a somehow related issue which I reported to the Compute Runtime as it can be seen as a build issue intel/compute-runtime#747.

[pszymich]

The patch has been reverted few times, we've since committed a final version of it in this commit: d4ba7fb
This one has finished testing and won't be reverted. Its internal build version is 17325, thus it will be available in a future release >= 1.0.17325.