[llvm] [llvm-dwarfdump] Make --verify for .debug_names multithreaded. (PR #127281)

[Greg Clayton via llvm-commits]

clayborg wrote:

> > Might be good to have to specify using multiple threads when verifying. So maybe opt into multi-threaded output to maintain deterministic output by default and allowing users to opt into non-deterministic output for speed? Something like
> > ```
> > --verify-multithreaded
> > ```
> > 
> > 
> >     
> >       
> >     
> > 
> >       
> >     
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> >     
> >   
> > If this is specified, then we can take full advantage of the speed at the cost of non-deterministic output.
> 
> I added a flag: --verify-num-threads. It defaults to system number of threads. Instead set it to 1?

That will be better to avoid anyone having different or unexpected output. If we change the default it can affect users that rely on this.

https://github.com/llvm/llvm-project/pull/127281