[LLVMdev] Interprocedural Register Allocation

[Jakob Stoklund Olesen]

On Oct 31, 2012, at 1:41 PM, Madhusudan C.S <madhusudancs at gmail.com> wrote:

>   I have spent last 4 weeks trying to figure out how to implement
> Interprocedural Register Allocation. I must admit that I was really
> overwhelmed with LLVM's codebase while trying to figure this out :)
> There is so much to know! I think I have reached a point where I
> have some sort of basic understanding of what needs to be done,
> but I need some help from here on. So here is the summary of
> what I know and for what I need more help.
> 
> I see that lib/CodeGen/Passes.cpp adds PrologEpilogInserter (PEI
> henceforth) pass after the RegAlloc pass. Do I understand correctly
> that LLVM first performs a given pass on all the functions before
> moving to the next pass?

No, it's the other way around.

You may want to read up on the pass manager and play with the -debug-pass option.

/jakob