GHC API: Access to nativeCodeGen?

[Peter A Jonsson]

dons at cse.unsw.edu.au (Donald Bruce Stewart) writes:
> pj:
> > I would like to use nativeCodeGen outside of GHC to generate code from
> > an IR. The IR would be produced by a third party program, not the GHC
> > frontend. 
> > 
> > Looking at CVS HEAD I can see that GHC.hs exports plenty of things
> > (for the GHC API I presume), but I can't find anything that lets me
> > input some sort of IR and have ASM in return. Am I missing it
> > somewhere or is there no way to input IR and get ASM in return? If
> > there isn't, is such a feature planned/wanted?
> > 
> > If such a feature isn't planned, I would appreciate any ideas on how
> > to to accomplish the same thing. I have no problems with having a
> > build tree of GHC laying around if that makes things easier. It would
> > be a nice bonus if it made my maintenance burden low.
>
> You could use External Core with GHC, couldn't you?

Thanks for the quick answer!

Maybe it's my lack of understanding of the inner workings of GHC but
reading "An External Representation for the GHC Core Language" I get
the impression that the dumping of Core Language is basically targeted
at researchers writing their own optimization passes or backends for
Haskell/GHC so they can use the existing infrastructure of GHC. My
request is the other way around - I want to throw out the frontend but
use* ("low-level") parts of the backend of GHC.

The Core Language seems to be translated into STG-machine code, which
according to my understanding is an abstract machine desinged to
support non-strict higher-order functional languages. I was hoping
that the laziness was in the STG-syntax, not in Cmm. Looking at output
of -ddump-cmm it resembles C-- quite closely (also implied by comments
in PprCmm.hs), which makes me believe that is the "correct" level of
abstraction for me.

*) The reasons are two-fold, one is that it is written in Haskell, the
   other is that it generates code for more than one architecture
   today.

/ Peter