[compiler-rt] Build with -DCOMPILER_RT_HAS_ATOMICS #24580
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It looks like without this the fallback functions are not actually thread safe: https://github.com/llvm/llvm-project/blob/63b80dd01dafc92104ee43e4f0f5296d644c25ec/compiler-rt/lib/profile/InstrProfilingUtil.c#L102-L119
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is it me or are these fallback functions kind of dangerous / wrong? |
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What looks wrong about them? They look like reasonable single-threaded implementations of compare-and-swap and fetch-add. |
tlively
approved these changes
Jun 16, 2025
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Right, but as we have shown by the need for this PR the In this case we were building without any macros and it was assuming incorrectly that single-theaded version could be substituted (even on multi-threaded builds). Perhaps it would be safer to invert the macro and have COMPILER_RT_SINGLE_THREADED_ONLY or some such. |
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It looks like without this the fallback functions are not actually thread safe:
https://github.com/llvm/llvm-project/blob/63b80dd01dafc92104ee43e4f0f5296d644c25ec/compiler-rt/lib/profile/InstrProfilingUtil.c#L102-L119
Followup to #24160