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Type:
Bug
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Status: Open
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Priority:
Medium
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Resolution: Unresolved
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Component/s: None
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Labels:None
When working on this change https://github.com/apple/swift/pull/32352 the windows tests failed unexpectedly. We tracked this down to the output containing these lines:
This valid one (that there should have been 2 of):
@__llvm_coverage_mapping = internal constant { { i32, i32, i32, i32 }, [1 x <{ i64, i32, i64 }>], [104 x i8] } { { i32, i32, i32, i32 } { i32 1, i32 94, i32 10, i32 2 }, [1 x <{ i64, i32, i64 }>] [<{ i64, i32, i64 }> <{ i64 346071021529087246, i32 9, i64 0 }>], [104 x i8] c"\01\\S:\\jenkins\\workspace\\swift-PR-windows\\swift\\test\\Profiler/Inputs/coverage_num_threads2.swift\01\00\00\01\01\01\0E\00\10\00" }, section ".lcovmap$M", align 8
And this invalid one where the `__ll` was cut off from the beginning:
@vm_coverage_mapping = internal constant { { i32, i32, i32, i32 }, [1 x <{ i64, i32, i64 }>], [104 x i8] } { { i32, i32, i32, i32 } { i32 1, i32 94, i32 10, i32 2 }, [1 x <{ i64, i32, i64 }>] [<{ i64, i32, i64 }> <{ i64 -8320429751471283630, i32 9, i64 0 }>], [104 x i8] c"\01\\S:\\jenkins\\workspace\\swift-PR-windows\\swift\\test\\Profiler/Inputs/coverage_num_threads1.swift\01\00\00\01\01\01\0E\00\10\00" }, section ".lcovmap$M", align 8
I found the missing `__ll` above in another line:
@__ll; ModuleID = '<swift-imported-modules>'
It seems like when using `-emit-ir` (and maybe other output methods) with `-num-threads` greater than 1, the output can become interleaved. I was never able to reproduce this on macOS, or my Windows VM, but it reproduced consistently on Windows CI.
