[PATCH] D76240: [Sanitizers][Test] If the default linker is LLD, disable threads

Thu Mar 19 09:11:26 PDT 2020

nemanjai added a comment.

In D76240#1930775 <https://reviews.llvm.org/D76240#1930775>, @grimar wrote:

> In D76240#1927115 <https://reviews.llvm.org/D76240#1927115>, @MaskRay wrote:
>
> > For lld, I think `--threads={0,1,2,...}` is better than the current `--(no-)threads`.
>
>
> BTW, can't testing with `--no-threads` hide possible LLDs concurency bugs?
>  We probably do not want to test LLD with `--(no-)threads` in most cases because it is not a real world use case of LLD.

I agree that this reduces the overall use of LLD with threading enabled while testing. However, I wouldn't characterize this as reducing test coverage for LLD because:

- This does not affect the actual LLD tests
- I would imagine that having a sanitizer test fail intermittently due to a bug caused by LLD's concurrency would actually be unlikely to lead the developer into an investigation of LLD, but rather to a waste of time investigating the sanitizer

I assume there aren't a large number of developers that build with `-DCLANG_DEFAULT_LINKER=lld`. For those that do, I think there are plenty of opportunities to test LLD through using the built compiler so that the loss of testing within the highly parallel `ninja check-all` testing of sanitizers is not that significant.

Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D76240/new/

https://reviews.llvm.org/D76240