[PATCH][PM] Add pass run listeners to the pass manager.

[Duncan P. N. Exon Smith]

On 2014-May-01, at 15:07, Juergen Ributzka <juergen at apple.com> wrote:

> Hi @ll,
> 
> I incorporated your suggestions into this patch. It extends the pass listener to also work with the new pass manager. There is some additional glue that can be removed
> once we get rid of the legacy pass manager. The C API has been reworked to accommodate future changes and additions to the pass listener.
> 
> The callback function signature has changed to incorporate an opaque user defined value and abstracts the current pass and IR behind a pass invocation reference.
> The invocation type specifies when this callback has been called. Currently this supports pre- and post-pass notification callbacks.
> 
> void (*LLVMPassListenerCallback)(void *Opaque, LLVMContextRef C, LLVMPassInvocationType T, LLVMPassInvocationRef P);
> 
> The pass invocation reference currently only supports one API - the pass name. This could be extended in the future to obtain the pass related IR, more pass related
> information, etc.
> 
> Cheers,
> Juergen
> 
> <0001-PM-Extend-pass-listener-to-also-work-with-the-new-pa.patch>

I like the PassInvocation design.  I wasn't quite sure what you were
planning here, but I think it solves the "what to pass back" problem
quite neatly, giving us flexibility in the future to expand the API.

This LGTM, with the following whitespace nitpick.

> @@ -1618,12 +1618,15 @@ MPPassManager::runOnModule(Module &M) {
>  
>      initializeAnalysisImpl(MP);
>  
> +    M.getContext().notifyPassPreRunListeners(MP, &M);
>      {
>        PassManagerPrettyStackEntry X(MP, M);
>        TimeRegion PassTimer(getPassTimer(MP));
>  
>        LocalChanged |= MP->runOnModule(M);
>      }
> +    M.getContext().notifyPassPostRunListeners(MP, &M);
> +

You inserted an extra newline here.

>  
>      Changed |= LocalChanged;
>      if (LocalChanged)
>