Bug 880615 – media-libs/mesa: -Dopencl-spriv and -Dintel-clc fail at runtime, unable to find LLVM

• Product: Gentoo Linux
• Status: RESOLVED FIXED

[Description darkbasic 2022-11-09 15:26:48 UTC]

Build mesa with -Dopencl-spirv=true to enable llvmpipe OpenCL implementation.
Now run LP_CL=1 clinfo and look at the errors:

=== CL_PROGRAM_BUILD_LOG ===
<built-in>:1:10: fatal error: 'opencl-c.h' file not found

This is because of the weird paths used by Gentoo's llvm slotting.

rusticl (Rust OpenCL implementation) suffers from the same issue, both at runtime and at compile time.

[Comment 1 Sam James 2022-11-09 15:29:52 UTC]

"Weird paths". This is obviously a bug in Mesa. LLVM has CMake config files and pkgconfig files to allow it to he found.

[Comment 2 darkbasic 2022-11-09 15:51:10 UTC]

ln -s /usr/lib/clang /usr/lib/llvm/15/lib64/clang fixes it

[Comment 3 Matt Turner 2022-11-10 01:29:16 UTC]

(In reply to darkbasic from comment #2)
> ln -s /usr/lib/clang /usr/lib/llvm/15/lib64/clang fixes it

This indeed allows the Mesa build to work with -Dintel-clc=enabled.

[Comment 4 Matt Turner 2022-11-14 22:04:06 UTC]

llvm@: I'm unsure what to do here. Please take a look.

I'm also seeing dev-libs/intel-compute-runtime fail to build because it cannot find libopencl-clang.so.14 (which is installed to /usr/lib/llvm/14/lib64/libopencl-clang.so.14)

[Comment 5 Michał Górny 2022-11-15 05:45:15 UTC]

The paths aren't "weird".  If you want to see some weird paths, try Debian:
https://packages.debian.org/bullseye/amd64/libclang-common-13-dev/filelist

The rough problem is that Debian is putting a lot of symlinks to let broken software build.  This is not a workable approach, and we shouldn't repeat it.  It only leads to people creating more broken software.

Also note that the /usr/lib/clang/* path is changing in LLVM 16 (upstream) from /x.y.z to /x.  Software is really expected to call `clang -print-resource-dir` to get the correct path rather than guessing.

[Comment 6 Karol Herbst 2022-11-20 14:49:16 UTC]

(In reply to Michał Górny from comment #5)
> The paths aren't "weird".  If you want to see some weird paths, try Debian:
> https://packages.debian.org/bullseye/amd64/libclang-common-13-dev/filelist
> 
> The rough problem is that Debian is putting a lot of symlinks to let broken
> software build.  This is not a workable approach, and we shouldn't repeat
> it.  It only leads to people creating more broken software.
> 
> Also note that the /usr/lib/clang/* path is changing in LLVM 16 (upstream)
> from /x.y.z to /x.  Software is really expected to call `clang
> -print-resource-dir` to get the correct path rather than guessing.

nobody wants to invoke clang at runtime. LLVM should just fix this mess and provide a way to get this path at _build time_.

[Comment 7 Karol Herbst 2022-12-01 19:02:55 UTC]

@darkbasic mind verifying that https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19617 fixes it?

[Comment 8 darkbasic 2022-12-01 19:49:28 UTC]

Created attachment 838695 [details, diff]
bb250a9f82a6694fdbfa58f77bf9f328d8d547f5-rebased.patch

[Comment 9 darkbasic 2022-12-01 19:49:46 UTC]

Created attachment 838697 [details, diff]
b96a59a91446d89e0812bd430f0e6ffcbea3b838-rebased.patch

[Comment 10 darkbasic 2022-12-01 19:50:54 UTC]

I had to modify your MR to apply on karolherbst/mesa.git#rusticl/si (see attached patches), but it works. Thanks!

[Comment 11 darkbasic 2022-12-02 21:03:59 UTC]

@Matt Turner please check intel-compute-runtime, otherwise this can be closed now.

[Comment 12 Matt Turner 2023-02-26 03:37:14 UTC]

(In reply to darkbasic from comment #11)
> @Matt Turner please check intel-compute-runtime, otherwise this can be
> closed now.

Yep, it compiles now.

[Comment 13 Larry the Git Cow 2023-05-12 17:18:55 UTC]

The bug has been referenced in the following commit(s):

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=9797e687d9bf332f49dc448791510e85efc20257

commit 9797e687d9bf332f49dc448791510e85efc20257
Author:     Niccolò Belli <[e-mail]>
AuthorDate: 2022-11-10 10:55:29 +0000
Commit:     Matt Turner <[e-mail]>
CommitDate: 2023-05-12 17:18:42 +0000

    media-libs/mesa: use rusticl instead of clover
    
    This has two notable regressions:
      - No multilib support
      - No R600 support
    
    Bug: https://bugs.gentoo.org/880615
    Closes: https://bugs.gentoo.org/872677
    Signed-off-by: Niccolò Belli <[e-mail]>
    Signed-off-by: Matt Turner <[e-mail]>

 media-libs/mesa/mesa-9999.ebuild        | 32 +++++++++++++++++---------------
 media-libs/mesa/metadata.xml            |  2 +-
 profiles/arch/x86/package.use.mask      |  4 ++++
 profiles/features/wd40/package.use.mask |  4 ++++
 4 files changed, 26 insertions(+), 16 deletions(-)