Re: getting Core Haskell from GHC API with cross-module inlinings
On 6/17/10, Roman Beslik ber...@ukr.net wrote:
Hi.
The following code compiles A.hs with GHC API:
{{{
import GHC
import Outputable
import DynFlags ( defaultDynFlags )
libdir = /usr/lib/ghc-6.12.1
targetFile = A.hs
main = defaultErrorHandler defaultDynFlags $ do
runGhc (Just libdir) $ do
dflags - fmap (\dflags - dflags {optLevel = 2}) getSessionDynFlags
Hi, Roman --
The problem you're seeing, where insufficient optimization occurs, is
in the above line. If I replace it with:
dflags - fmap (updOptLevel 2) getSessionDynFlags
then I get a result where maybe has been inlined away. The reason is
that the optimization sequence is controlled by several different
fields within DynFlags, and just changing the optLevel field doesn't
update the other fields. The updOptLevel function (defined in
DynFlags, so you'll have to import that module explicitly) does.
Also, I don't know what you're trying to do, but I recommend looking
at GHC's External Core feature:
http://www.haskell.org/ghc/docs/6.12.2/html/users_guide/ext-core.html
and at the extcore and linkcore libraries:
http://hackage.haskell.org/package/extcore
http://hackage.haskell.org/package/linkcore
IMO, it's easier than using the API to generate Core. If you find any
problems with External Core or the packages above, let me know (I'm
the maintainer).
Cheers,
Tim
--
Tim Chevalier * http://cs.pdx.edu/~tjc * Often in error, never in doubt
I knew I'd hate Cobol the moment I saw they'd used 'perform' instead
of 'do'. -- Larry Wall
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Re: getting Core Haskell from GHC API with cross-module inlinings
On 21.06.10 21:45, Tim Chevalier wrote: Also, I don't know what you're trying to do, but I recommend looking at GHC's External Core feature: http://www.haskell.org/ghc/docs/6.12.2/html/users_guide/ext-core.html and at the extcore and linkcore libraries: http://hackage.haskell.org/package/extcore http://hackage.haskell.org/package/linkcore Thanks, Tim. I will look into it. I'm trying to: - get source code on different stages of processing in GHC; - dig to the GHC function which is responsible for some alteration in a source code. It is hard to trace a link between source code appearing as values in GHC functions and what -ddump-simpl outputs. And I guess that -ddump-simpl provides too coarse control of source code processing. So I try to call GHC functions directly. It is important that source code processing in GHC and libraries you mentioned (and the ghc library) should be identical. -- Best regards, Roman Beslik. ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: getting Core Haskell from GHC API with cross-module inlinings
On 6/21/10, Roman Beslik ber...@ukr.net wrote: I'm trying to: - get source code on different stages of processing in GHC; Probably not hard to do by giving different combinations of compiler flags -- you could do this with either the API or External Core. - dig to the GHC function which is responsible for some alteration in a source code. That would be harder. It would require modifying GHC quite a bit, but I could imagine getting there by using Core's Note construct and then getting the results as External Core. It is hard to trace a link between source code appearing as values in GHC functions and what -ddump-simpl outputs. And I guess that -ddump-simpl Indeed, I think that including enough information in an External Core file, or internal Core module, to map any value back to the original Haskell expression would be a research project in and of itself. Part of that project would involve specifying exactly what the original Haskell expression means -- for example, in the presence of aggressive inlining... Cheers, Tim -- Tim Chevalier * http://cs.pdx.edu/~tjc * Often in error, never in doubt In a land of quince jelly, apple butter, apricot jam, blueberry preserves, pear conserves, and lemon marmalade, you always get grape jelly. -- William Least Heat-Moon ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
getting Core Haskell from GHC API with cross-module inlinings
Hi.
The following code compiles A.hs with GHC API:
{{{
import GHC
import Outputable
import DynFlags ( defaultDynFlags )
libdir = /usr/lib/ghc-6.12.1
targetFile = A.hs
main = defaultErrorHandler defaultDynFlags $ do
runGhc (Just libdir) $ do
dflags - fmap (\dflags - dflags {optLevel = 2})
getSessionDynFlags
setSessionDynFlags dflags
c - compileToCoreSimplified targetFile
print (showSDoc (ppr c))
}}}
A.hs: {{{
import Data.Maybe
main = print (show (maybe False (\_ - True) (Just False)))
}}}
When A.hs is compiled with GHC API, output contains a reference to
'maybe'. When A.hs is compiled with ghc -O2 -ddump-simpl, 'maybe' is
inlined and simplified. Why do outputs differ?
--
Best regards,
Roman Beslik.
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