[PATCH] D127812: [AArch64] FMV support and necessary target features dependencies.

Wed Dec 21 09:42:24 PST 2022

hctim added a comment.

In D127812#4010856 <https://reviews.llvm.org/D127812#4010856>, @ilinpv wrote:

> It would be great to have more details how to setup up your bot, using buildbot_fast.sh on x86_64 Ubuntu 22.04 LTS leads to error ( pthreads installed ):
>
>   CMake Error at /usr/share/cmake-3.22/Modules/FindPackageHandleStandardArgs.cmake:230 (message):
>     Could NOT find Threads (missing: Threads_FOUND)
>   Call Stack (most recent call first):
>     /usr/share/cmake-3.22/Modules/FindPackageHandleStandardArgs.cmake:594 (_FPHSA_FAILURE_MESSAGE)
>     /usr/share/cmake-3.22/Modules/FindThreads.cmake:238 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
>     cmake/config-ix.cmake:114 (find_package)
>     CMakeLists.txt:776 (include)
>
> Also MemorySanitizer: use-of-uninitialized-value cases from https://lab.llvm.org/buildbot/#/builders/5/builds/30139 looks fine locally, all values initialized, could MSAN produce false positive results?

MSan can find false positives, but that's only if code ends up in your binary that isn't built with MSan. The buildscripts are written so that everything gets instrumented.

Hmm, not exactly sure what's going on with the `could NOT find Threads` there. A quick googling seems to point to pthreads.so not being in the right places, but I don't think the buildbot does anything special. Do your regular builds with `-DLLVM_ENABLE_PROJECTS="compiler_rt;clang;lld"` work?

When you say that it looks fine locally, is that from your own checkout but using `-DLLVM_USE_SANITIZER=Memory`? First thing to check is that you do end up with MSan in the test (in particular the clang binary that's being produced), which you can do by `nm bin/clang-16 | grep __msan_init`.

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https://reviews.llvm.org/D127812