Package abi hash and interface file versions

[Simon Marlow]

On 14/07/2011 09:28, Joachim Breitner wrote:

> Am Mittwoch, den 13.07.2011, 14:09 +0200 schrieb Joachim Breitner:
>> Even if you do not plan to support modules across minor versions of ghc,
>> I’d like to get that into the hash. This would save us the trouble of
>> tracking which package was built with what version of ghc and the same
>> rebuild logic would apply that already handles the case of updated
>> package dependencies.
>
> looking at the code, all that is needed would be to modify this file in
> ghc/Main.hs, and add something like the marked line to it (untested, as
> I do not have a partial build lying around, and my machine sometimes
> doesn’t take the heat from building ghc without crashing :-( ):
>
> abiHash :: [(String, Maybe Phase)] ->  Ghc ()
> abiHash strs = do
>    hsc_env<- getSession
>    let dflags = hsc_dflags hsc_env
>
>    liftIO $ do
>
>    let find_it str = do
>           let modname = mkModuleName str
>           r<- findImportedModule hsc_env modname Nothing
>           case r of
>             Found _ m ->  return m
>             _error    ->  ghcError $ CmdLineError $ showSDoc $
>                            cannotFindInterface dflags modname r
>
>    mods<- mapM find_it (map fst strs)
>
>    let get_iface modl = loadUserInterface False (text "abiHash") modl
>    ifaces<- initIfaceCheck hsc_env $ mapM get_iface mods
>
>    bh<- openBinMem (3*1024) -- just less than a block
>    put_ bh opt_HiVersion -- would adding this be sufficient
>    mapM_ (put_ bh . mi_mod_hash) ifaces
>    f<- fingerprintBinMem bh
>
>    putStrLn (showSDoc (ppr f))
>
>
> Haskell is currently broken in Debian on i386 and other arches and I’d
> like to get this fix in quickly, but of course not without upstream
> review.

So that will only affect the hash on the package, not the ABI hashes on 
individual modules.  Maybe that's ok, but I have to think it through.

Cheers,
	Simon