[llvm] [llvm-mca] Abort on parse error without -skip-unsupported-instructions (PR #90474)

[Peter Waller via llvm-commits]

peterwaller-arm wrote:

I'm happy having a separate flag if that seems beneficial (commence bikeshed: `-skip-parse-errors`? Naming seems tricky given that the parser emits errors if you use instructions which are not supported with the current feature flags, for example).

However, I'm unclear on how beneficial it is to split this case up to a user. A user would still be able to distinguish the two according to the stderr errors (and warnings, notes) that are printed.

Do we really want to force a user to distinguish the reasons for skipping the flags on input? Essentially, if I was faced with a failure due to the presence of some instructions on the input, I would want to reach for the one obvious flag to proceed, rather than to have to figure out which of the N > 1 flags it is.

Another possibility would be to have -skip-unsupported-instructions not be just a bool but a flag that takes multiple options, ranging from `-skip-unsupported-instructions=no-sched-info`, `-skip-unsupported-instructions=parse-failure` to `-skip-unsupported-instructions=all`.

https://github.com/llvm/llvm-project/pull/90474