Fix LLVM find package picking up system-wide libraries #1866
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
The committers listed above are authorized under a signed CLA. |
|
LGTM, thanks! We will need the commit DCO-signed and a CLA on file before we can merge. |
This change fixes LLVM find package ignoring the library path provided by LLVM_CONFIG and picking up a system-wide library instead. This happens when a custom LLVM is compiled statically, and there is a system-wide LLVM of the version which OSL expects. The solution is to pass NO_DEFAULT_PATH to the find_library so that the function only considers paths explicitly coming from the LLVM's configuration executable. It is a bit unclear what is the expected behavior of this module when LLVM_CONFIG is not available. It is possible to limit possible side effects of this change by only ignoring default paths if the LLVM CONFIG executable is found. In practice this issue happened in Blender's build environment where HIP is used for OpenImageDenoiser: HIP toolchain pulls in LLVM system wide. While it is not an issue on itself (as it is only a compile time dependency for HIP support in OIDN) in conflicts with the logic in the OSL's find_package(LLVM). Signed-off-by: Sergey Sharybin <[email protected]>
sergeyvfx
force-pushed
the
find_package_llvm
branch
from
1d5ccd8 to
0366d4d
Compare
lgritz
pushed a commit
to lgritz/OpenShadingLanguage
that referenced
this pull request
Sep 24, 2024
…ySoftwareFoundation#1866) This change fixes LLVM find package ignoring the library path provided by LLVM_CONFIG and picking up a system-wide library instead. This happens when a custom LLVM is compiled statically, and there is a system-wide LLVM of the version which OSL expects. The solution is to pass NO_DEFAULT_PATH to the find_library so that the function only considers paths explicitly coming from the LLVM's configuration executable. It is a bit unclear what is the expected behavior of this module when LLVM_CONFIG is not available. It is possible to limit possible side effects of this change by only ignoring default paths if the LLVM CONFIG executable is found. In practice this issue happened in Blender's build environment where HIP is used for OpenImageDenoiser: HIP toolchain pulls in LLVM system wide. While it is not an issue on itself (as it is only a compile time dependency for HIP support in OIDN) in conflicts with the logic in the OSL's find_package(LLVM). Signed-off-by: Sergey Sharybin <[email protected]>
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Description
This change fixes LLVM find package ignoring the library path provided by LLVM_CONFIG and picking up a system-wide library instead.
This happens when a custom LLVM is compiled statically, and there is a system-wide LLVM of the version which OSL expects.
The solution is to pass NO_DEFAULT_PATH to the find_library so that the function only considers paths explicitly coming from the LLVM's configuration executable.
It is a bit unclear what is the expected behavior of this module when LLVM_CONFIG is not available. It is possible to limit possible side effects of this change by only ignoring default paths if the LLVM CONFIG executable is found.
In practice this issue happened in Blender's build environment where HIP is used for OpenImageDenoiser: HIP toolchain pulls in LLVM system wide. While it is not an issue on itself (as it is only a compile time dependency for HIP support in OIDN) in conflicts with the logic in the OSL's find_package(LLVM).
Tests
The change has been tested in the build environment which is used for official Blender libraries builds. For the details of this environment one might read its documentation.
Running the official testsuite produces a fair amount of failures before this change. Could be due to the side effects of how that specific VM is setup, didn't have time yet to dig into exact details.
Checklist:
already run clang-format v17 before submitting, I definitely will look at
the CI test that runs clang-format and fix anything that it highlights as
being nonconforming.