[llvm] applying Floating-Point Numerical Sanitizer patch

[smuzaffar]

Added llvm Floating-Point Numerical Sanitizer llvm/llvm-project#85916

FYI @VinInn

[smuzaffar]

please test

[cmsbuild]

A new Pull Request was created by @smuzaffar for branch IB/CMSSW_14_1_X/master.

@aandvalenzuela, @smuzaffar, @iarspider can you please review it and eventually sign? Thanks.
@sextonkennedy, @antoniovilela, @rappoccio you are the release manager for this.
cms-bot commands are listed here

[cmsbuild]

cms-bot internal usage

[cmsbuild]

-1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-0d3956/39452/summary.html
COMMIT: 161fe72
CMSSW: CMSSW_14_1_X_2024-05-20-2300/el8_amd64_gcc12
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week0/cms-sw/cmsdist/9201/39452/install.sh to create a dev area with all the needed externals and cmssw changes.

External Build

I found compilation warning when building: See details on the summary page.

[smuzaffar]

please test

[cmsbuild]

Pull request #9201 was updated.

[cmsbuild]

-1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-0d3956/39453/summary.html
COMMIT: 40209eb
CMSSW: CMSSW_14_1_X_2024-05-20-2300/el8_amd64_gcc12
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week0/cms-sw/cmsdist/9201/39453/install.sh to create a dev area with all the needed externals and cmssw changes.

External Build

I found compilation error when building:

patching file llvm/test/Instrumentation/NumericalStabilitySanitizer/basic.ll
patching file llvm/test/Instrumentation/NumericalStabilitySanitizer/cfg.ll
patching file llvm/test/Instrumentation/NumericalStabilitySanitizer/invoke.ll
patching file llvm/test/Instrumentation/NumericalStabilitySanitizer/memory.ll
patching file llvm/test/Instrumentation/NumericalStabilitySanitizer/non_float_store.ll
error: Bad exit status from /data/cmsbld/jenkins/workspace/ib-run-pr-tests/testBuildDir/tmp/rpm-tmp.hXZZMU (%prep)


RPM build errors:
line 37: It's not recommended to have unversioned Obsoletes: Obsoletes: external+llvm+17.0.3-18bbc4ca84d2b4b92fa29e7ab26ed099
Macro expanded in comment on line 368: %{pkginstroot}/lib64


[VinInn]

Is the patch broken?

[fwyzard]

I see that the upstream PR (llvm/llvm-project#85916) is still under review, with various changes being applied.

[smuzaffar]

yes, it is broken. Though I have updated it ( e.g. cms-externals/llvm-project#15 ) to be patched on top of llvm 18.1.6 but the command ninja check-nsan is not yet implemented . It fails at build time

Total Discovered Tests: 2812
Unsupported      :    8 (0.28%)
Passed           : 2802 (99.64%)
Expectedly Failed:    2 (0.07%)
+ ninja -v -j 16 check-nsan
ninja: error: unknown target 'check-nsan', did you mean 'check-lsan'?

[alexander-shaposhnikov]

just in case - my original PR got split (per reviewers' request), currently llvm/llvm-project#85916 contains the instrumentation pass only, the newly added tests can be run via ninja check-llvm-instrumentation.

[VinInn]

@alexander-shaposhnikov thanks for the info.
Does it mean that the UI (and notification?) is not yet present?
Can it be used to instrument a user program and get a report of "errors"?

[alexander-shaposhnikov]

@VinInn - one can give it a try with a few caveats: the tool is very experimental, the coverage is incomplete (most notable blind spots are vector intrinsics and half precision). If you'd like - I can put together a combined (updated) version similar to my initial PR with all the components (instrumentation pass, runtime (compiler-rt), frontend/driver (clang)) and push it into my github repo. In this case you'll be able to run all the in-tree numerical tests via check-nsan and experiment with it by passing -fsanitize=numerical to Clang

[VinInn]

Thanks @alexander-shaposhnikov for the very complete answer.
for what concern the "private" updated version that would be interesting if the official version will take a while to concretize.
So please, if you have the time, go ahead with a updated version in your repository.

Thanks