[llvm-exegesis][NFC] Disassociate snippet generators from benchmark runners

[mstojanovic]

Summary

The addition of inverse_throughput mode highlighted the disjointedness of snippet generators and benchmark runners because it used the UopsSnippetGenerator with the LatencyBenchmarkRunner. To keep the code consistent tie the snippet generators to parallelization/serialization rather than their benchmark runners.

Renaming LatencySnippetGenerator -> SerialSnippetGenerator.
Renaming UopsSnippetGenerator -> ParallelSnippetGenerator.
Renaming Uops -> Parallel in types and functions related to the ParallelSnippetGenerator.

[mstojanovic]

llvm/tools/llvm-exegesis/lib/ParallelSnippetGenerator.cpp

17–20

I'm not sure how this can be reworded to reflect that it deals with parallel instructions in general rather than just the uops case.

llvm/tools/llvm-exegesis/lib/SerialSnippetGenerator.cpp

11–19

It's not easy to determine which headers are needed here when splitting the files. Most of them seem to be unused.

[courbet]

llvm/tools/llvm-exegesis/lib/ParallelSnippetGenerator.cpp

17–20

Maybe :
"Ideally we would like the only limitation on executing instructions to be the availability of the CPU resources (e.g. execution ports) needed to execute them, instead of the availability of their data dependencies."

[mstojanovic]

Updated the comment.

[courbet]

Thanks.

llvm/tools/llvm-exegesis/lib/SerialSnippetGenerator.cpp

11–19

I could not find anything obvious that would require any of these and not already use din the header.

Headers are missing for vector, iota and shuffle though.

[mstojanovic]

Added includes for vector, iota and shuffle.
Renamed writeUopsSnippetHtml() -> writeParallelSnippetHtml().

llvm/tools/llvm-exegesis/lib/ParallelSnippetGenerator.cpp

42

Should this be reworded similarly to the comment above?

[courbet]

llvm/tools/llvm-exegesis/lib/ParallelSnippetGenerator.cpp

42

I think this one is fine since we gave ports as an example for resources before.

[mstojanovic]

Ok, thank you for the review!