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

[Peter Waller via llvm-commits]

peterwaller-arm wrote:

Thanks for coming around and allowing my side :). I am also motivated to keep things simple.

Ideally the decision isn't permanent; I hope we make a design now which gives a way forward where we can extend things for more specificity if new information comes to light.

So that said I'm swinging back to this proposal, which is my current intent.

> https://github.com/llvm/llvm-project/pull/90474#issuecomment-2083198408
>
> OK, I propose to:
> 
> * make llvm-mca report an error and exit by default
> * make -skip-unsupported-instructions take no-sched-info, parse-error and all.
> * parse-error would skip the case Parser->Run(false) returning true (indicating error).


That is:

* In aid of keeping things simple we have one flag, `-skip-unsupported-instructions`, and it takes `no-sched-info`, `parse-error` and `all`. If it becomes desirable to add more distinction it should be possible to add other values to this option.
* The flag describes what it is doing, which is skipping over instructions on the input.

I'll hold off implementing this for a day or two in case there are more comments refining this.



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