[PATCH] D24376: [XRay] Implement `llvm-xray convert` -- trace file conversion

[David Blaikie via llvm-commits]

dblaikie added a comment.

In https://reviews.llvm.org/D24376#603715, @dberris wrote:

> In https://reviews.llvm.org/D24376#602808, @dblaikie wrote:
>
> > (I was thinking more going the other direction: removing the dead code, rather than adding a use of it)
> >
> > What's the purpose of the binary/raw output format? (I think it was mentioned that the binary output format would be for testing - so we could write yaml, then generate raw files - then feed those into other tools for testing? But if the yaml input format is supported everywhere, what's the purpose of that? We'll want to have a couple of binary tests, but I imagine they would test checked in binary -> yaml output (if they test yaml -> binary -> yaml, then I'm not sure they achieve much because it's just roundtripping so we have as much code under test (binary -> yaml) as we do in the test harness (yaml -> binary), effectively)
> >
> > That's my mental model at least.
>
>
> Other things going on concurrently (work on the FDR mode for the runtime library) is making me need to be able to turn versions of the binary log from one form to another. I've found that working with the binary versions is much more convenient from a tool perspective, and that this current simple format is more amenable to analysis than the condensed format I'm working on.


I'm not sure I'm following here - could you describe this in more detail?

My understanding was that tools would likely use these LLVM APIs for data handling (or they'd use YAML input) - so there wouldn't be any benefit to any particular format (except YAML) since these LLVM APIs could handle all the formats. This would make the binary format(s) fairly niche - just convenient for runtime emission, but not desirable for any other use.

Where have I gone wrong here?

> So effectively, version 2 of the log format is turning out to have both non-fixed-size records and more interleaving happening. This tool, that's able to take that complex format into something simpler/different doesn't make sense for generating just YAML files.
> 
>> (this commit seems to add several .bin test files - but I don't see where those are used?)
> 
> Some of the tests are looking at symbolization of the function id's, and associating functions with debug info, etc. for coverage of the various modes by which the YAML output could be generated.

Not quite following, more practically: which tests are these files used in?


https://reviews.llvm.org/D24376