\section[SimplCore]{Driver for simplifying @Core@ programs}
\begin{code}
-#include "HsVersions.h"
-
module SimplCore ( core2core ) where
-IMP_Ubiq(){-uitous-}
-IMPORT_1_3(IO(hPutStr,stderr))
+#include "HsVersions.h"
import AnalFBWW ( analFBWW )
import Bag ( isEmptyBag, foldBag )
import CoreUnfold
import Literal ( Literal(..), literalType, mkMachInt )
import ErrUtils ( ghcExit, dumpIfSet, doIfSet )
-import FiniteMap ( FiniteMap )
+import FiniteMap ( FiniteMap, emptyFM )
import FloatIn ( floatInwards )
import FloatOut ( floatOutwards )
import FoldrBuildWW ( mkFoldrBuildWW )
-import Id ( mkSysLocal, setIdVisibility, replaceIdInfo,
- replacePragmaInfo, getIdDemandInfo, idType,
- getIdInfo, getPragmaInfo, mkIdWithNewUniq,
+import MkId ( mkSysLocal, mkUserId )
+import Id ( setIdVisibility, getIdSpecialisation, setIdSpecialisation,
+ getIdDemandInfo, idType,
nullIdEnv, addOneToIdEnv, delOneFromIdEnv,
- lookupIdEnv, SYN_IE(IdEnv), omitIfaceSigForId,
- apply_to_Id,
- GenId{-instance Outputable-}, SYN_IE(Id)
+ lookupIdEnv, IdEnv,
+ Id
)
import IdInfo ( willBeDemanded, DemandInfo )
import Name ( isExported, isLocallyDefined,
isLocalName, uniqToOccName,
- SYN_IE(Module), NamedThing(..), OccName(..)
+ setNameVisibility,
+ Module, NamedThing(..), OccName(..)
)
import TyCon ( TyCon )
import PrimOp ( PrimOp(..) )
integerZeroId, integerPlusOneId,
integerPlusTwoId, integerMinusOneId
)
-import Type ( maybeAppDataTyCon, isPrimType, SYN_IE(Type) )
+import Type ( splitAlgTyConApp_maybe, isUnpointedType, Type )
import TysWiredIn ( stringTy, isIntegerTy )
import LiberateCase ( liberateCase )
import MagicUFs ( MagicUnfoldingFun )
-import Outputable ( pprDumpStyle, printErrs,
- PprStyle(..), Outputable(..){-instance * (,) -}
- )
import PprCore
-import PprType ( GenType{-instance Outputable-}, GenTyVar{-ditto-},
- nmbrType
- )
-import Pretty ( Doc, vcat, ($$), hsep )
+import PprType ( nmbrType )
import SAT ( doStaticArgs )
import SimplMonad ( zeroSimplCount, showSimplCount, SimplCount )
import SimplPgm ( simplifyPgm )
import Specialise
-import SpecUtils ( pprSpecErrs )
+import SpecEnv ( substSpecEnv, isEmptySpecEnv )
import StrictAnal ( saWwTopBinds )
-import TyVar ( SYN_IE(TyVar), nullTyVarEnv, GenTyVar{-instance Eq-},
- nameTyVar
- )
+import TyVar ( TyVar, nameTyVar, emptyTyVarEnv )
import Unique ( Unique{-instance Eq-}, Uniquable(..),
integerTyConKey, ratioTyConKey,
mkUnique, incrUnique,
import UniqSupply ( UniqSupply, mkSplitUniqSupply,
splitUniqSupply, getUnique
)
-import UniqFM ( UniqFM, lookupUFM, addToUFM )
-import Usage ( SYN_IE(UVar), cloneUVar )
-import Util ( mapAccumL, assertPanic, panic{-ToDo:rm-}, pprTrace, pprPanic )
+import UniqFM ( UniqFM, lookupUFM, addToUFM, delFromUFM )
+import Util ( mapAccumL )
import SrcLoc ( noSrcLoc )
import Constants ( tARGET_MIN_INT, tARGET_MAX_INT )
import Bag
import Maybes
-
-
-#ifndef OMIT_DEFORESTER
-import Deforest ( deforestProgram )
-import DefUtils ( deforestable )
-#endif
-
+import IO ( hPutStr, stderr )
+import Outputable
\end{code}
\begin{code}
-> FAST_STRING -- module name (profiling only)
-> UniqSupply -- a name supply
-> [TyCon] -- local data tycons and tycon specialisations
- -> FiniteMap TyCon [(Bool, [Maybe Type])]
-> [CoreBinding] -- input...
- -> IO
- ([CoreBinding], -- results: program, plus...
- SpecialiseData) -- specialisation data
+ -> IO [CoreBinding] -- results: program
-core2core core_todos module_name us local_tycons tycon_specs binds
+core2core core_todos module_name us local_tycons binds
= -- Do the main business
foldl_mn do_core_pass
- (binds, us, init_specdata, zeroSimplCount)
+ (binds, us, zeroSimplCount)
core_todos
- >>= \ (processed_binds, us', spec_data, simpl_stats) ->
+ >>= \ (processed_binds, us', simpl_stats) ->
-- Do the final tidy-up
let
-- Dump output
dumpIfSet (opt_D_dump_simpl || opt_D_verbose_core2core)
"Core transformations"
- (pprCoreBindings pprDumpStyle final_binds) >>
+ (pprCoreBindings final_binds) >>
-- Report statistics
doIfSet opt_D_simplifier_stats
hPutStr stderr "\n") >>
-- Return results
- return (final_binds, spec_data)
+ return final_binds
where
- init_specdata = initSpecData local_tycons tycon_specs
-
--------------
- do_core_pass info@(binds, us, spec_data, simpl_stats) to_do =
+ do_core_pass info@(binds, us, simpl_stats) to_do =
case (splitUniqSupply us) of
(us1,us2) ->
case to_do of
then " (foldr/build)" else "") >>
case (simplifyPgm binds simpl_sw_chkr simpl_stats us1) of
(p, it_cnt, simpl_stats2)
- -> end_pass us2 p spec_data simpl_stats2
+ -> end_pass us2 p simpl_stats2
("Simplify (" ++ show it_cnt ++ ")"
++ if switchIsOn simpl_sw_chkr SimplDoFoldrBuild
then " foldr/build" else "")
-> _scc_ "CoreDoFoldrBuildWorkerWrapper"
begin_pass "FBWW" >>
case (mkFoldrBuildWW us1 binds) of { binds2 ->
- end_pass us2 binds2 spec_data simpl_stats "FBWW" }
+ end_pass us2 binds2 simpl_stats "FBWW" }
CoreDoFoldrBuildWWAnal
-> _scc_ "CoreDoFoldrBuildWWAnal"
begin_pass "AnalFBWW" >>
case (analFBWW binds) of { binds2 ->
- end_pass us2 binds2 spec_data simpl_stats "AnalFBWW" }
+ end_pass us2 binds2 simpl_stats "AnalFBWW" }
CoreLiberateCase
-> _scc_ "LiberateCase"
begin_pass "LiberateCase" >>
case (liberateCase opt_LiberateCaseThreshold binds) of { binds2 ->
- end_pass us2 binds2 spec_data simpl_stats "LiberateCase" }
+ end_pass us2 binds2 simpl_stats "LiberateCase" }
CoreDoFloatInwards
-> _scc_ "FloatInwards"
begin_pass "FloatIn" >>
case (floatInwards binds) of { binds2 ->
- end_pass us2 binds2 spec_data simpl_stats "FloatIn" }
+ end_pass us2 binds2 simpl_stats "FloatIn" }
CoreDoFullLaziness
-> _scc_ "CoreFloating"
begin_pass "FloatOut" >>
case (floatOutwards us1 binds) of { binds2 ->
- end_pass us2 binds2 spec_data simpl_stats "FloatOut" }
+ end_pass us2 binds2 simpl_stats "FloatOut" }
CoreDoStaticArgs
-> _scc_ "CoreStaticArgs"
begin_pass "StaticArgs" >>
case (doStaticArgs binds us1) of { binds2 ->
- end_pass us2 binds2 spec_data simpl_stats "StaticArgs" }
+ end_pass us2 binds2 simpl_stats "StaticArgs" }
-- Binds really should be dependency-analysed for static-
-- arg transformation... Not to worry, they probably are.
-- (I don't think it *dies* if they aren't [WDP 94/04/15])
-> _scc_ "CoreStranal"
begin_pass "StrAnal" >>
case (saWwTopBinds us1 binds) of { binds2 ->
- end_pass us2 binds2 spec_data simpl_stats "StrAnal" }
+ end_pass us2 binds2 simpl_stats "StrAnal" }
CoreDoSpecialising
-> _scc_ "Specialise"
begin_pass "Specialise" >>
- case (specProgram us1 binds spec_data) of {
- (p, spec_data2@(SpecData _ spec_noerrs _ _ _
- spec_errs spec_warn spec_tyerrs)) ->
-
- -- if we got errors, we die straight away
- doIfSet ((not spec_noerrs) ||
- (opt_ShowImportSpecs && not (isEmptyBag spec_warn)))
- (printErrs
- (pprSpecErrs module_name spec_errs spec_warn spec_tyerrs))
- >>
-
- doIfSet (not spec_noerrs) -- Stop here if specialisation errors occured
- (ghcExit 1) >>
-
- end_pass us2 p spec_data2 simpl_stats "Specialise"
+ case (specProgram us1 binds) of { p ->
+ end_pass us2 p simpl_stats "Specialise"
}
- CoreDoDeforest
-#if OMIT_DEFORESTER
- -> error "ERROR: CoreDoDeforest: not built into compiler\n"
-#else
- -> _scc_ "Deforestation"
- begin_pass "Deforestation" >>
- case (deforestProgram binds us1) of { binds2 ->
- end_pass us2 binds2 spec_data simpl_stats "Deforestation" }
-#endif
-
CoreDoPrintCore -- print result of last pass
-> dumpIfSet (not opt_D_verbose_core2core) "Print Core"
- (pprCoreBindings pprDumpStyle binds) >>
- return (binds, us1, spec_data, simpl_stats)
+ (pprCoreBindings binds) >>
+ return (binds, us1, simpl_stats)
-------------------------------------------------
else return ()
end_pass us2 binds2
- spec_data2@(SpecData spec_done _ _ _ _ _ _ _)
simpl_stats2 what
= -- Report verbosely, if required
dumpIfSet opt_D_verbose_core2core what
- (pprCoreBindings pprDumpStyle binds2) >>
+ (pprCoreBindings binds2) >>
- lintCoreBindings what spec_done binds2 >>
+ lintCoreBindings what True {- spec_done -} binds2 >>
+ -- The spec_done flag tells the linter to
+ -- complain about unboxed let-bindings
+ -- But we're not specialising unboxed types any more,
+ -- so its irrelevant.
return
(binds2, -- processed binds, possibly run thru CoreLint
us2, -- UniqSupply for the next guy
- spec_data2, -- possibly-updated specialisation info
simpl_stats2 -- accumulated simplifier stats
)
Several tasks are done by @tidyCorePgm@
-1. Eliminate indirections. The point here is to transform
- x_local = E
- x_exported = x_local
- ==>
- x_exported = E
+----------------
+ [March 98] Indirections are now elimianted by the occurrence analyser
+ -- 1. Eliminate indirections. The point here is to transform
+ -- x_local = E
+ -- x_exported = x_local
+ -- ==>
+ -- x_exported = E
2. Make certain top-level bindings into Globals. The point is that
Global things get externally-visible labels at code generation
generator makes global labels from the uniques for local thunks etc.]
-Eliminate indirections
-~~~~~~~~~~~~~~~~~~~~~~
-In @elimIndirections@, we look for things at the top-level of the form...
-\begin{verbatim}
- x_local = ....
- x_exported = x_local
-\end{verbatim}
-In cases we find like this, we go {\em backwards} and replace
-\tr{x_local} with \tr{x_exported}. This save a gratuitous jump
-(from \tr{x_exported} to \tr{x_local}), and makes strictness
-information propagate better.
-
-We rely on prior eta reduction to simplify things like
-\begin{verbatim}
- x_exported = /\ tyvars -> x_local tyvars
-==>
- x_exported = x_local
-\end{verbatim}
-
-If more than one exported thing is equal to a local thing (i.e., the
-local thing really is shared), then we do one only:
-\begin{verbatim}
- x_local = ....
- x_exported1 = x_local
- x_exported2 = x_local
-==>
- x_exported1 = ....
-
- x_exported2 = x_exported1
-\end{verbatim}
-
-There's a possibility of leaving unchanged something like this:
-\begin{verbatim}
- x_local = ....
- x_exported1 = x_local Int
-\end{verbatim}
-By the time we've thrown away the types in STG land this
-could be eliminated. But I don't think it's very common
-and it's dangerous to do this fiddling in STG land
-because we might elminate a binding that's mentioned in the
-unfolding for something.
-
-General Strategy: first collect the info; then make a \tr{Id -> Id} mapping.
-Then blast the whole program (LHSs as well as RHSs) with it.
-
\begin{code}
tidyCorePgm :: Module -> [CoreBinding] -> [CoreBinding]
tidyCorePgm mod binds_in
- = initTM mod indirection_env $
- tidyTopBindings (catMaybes reduced_binds) `thenTM` \ binds ->
+ = initTM mod nullIdEnv $
+ tidyTopBindings binds_in `thenTM` \ binds ->
returnTM (bagToList binds)
- where
- (indirection_env, reduced_binds) = mapAccumL try_bind nullIdEnv binds_in
-
- try_bind :: IdEnv CoreBinder -> CoreBinding -> (IdEnv CoreBinder, Maybe CoreBinding)
- try_bind env_so_far (NonRec exported_binder rhs)
- | isExported exported_binder && -- Only if this is exported
- maybeToBool maybe_rhs_id && -- and the RHS is a simple Id
-
- isLocallyDefined rhs_id && -- Only if this one is defined in this
- -- module, so that we *can* change its
- -- binding to be the exported thing!
-
- not (isExported rhs_id) && -- Only if this one is not itself exported,
- -- since the transformation will nuke it
-
- not (omitIfaceSigForId rhs_id) && -- Don't do the transformation if rhs_id is
- -- something like a constructor, whose
- -- definition is implicitly exported and
- -- which must not vanish.
- -- To illustrate the preceding check consider
- -- data T = MkT Int
- -- mkT = MkT
- -- f x = MkT (x+1)
- -- Here, we'll make a local, non-exported, defn for MkT, and without the
- -- above condition we'll transform it to:
- -- mkT = \x. MkT [x]
- -- f = \y. mkT (y+1)
- -- This is bad because mkT will get the IdDetails of MkT, and won't
- -- be exported. Also the code generator won't make a definition for
- -- the MkT constructor.
- -- Slightly gruesome, this.
-
- not (maybeToBool (lookupIdEnv env_so_far rhs_id))
- -- Only if not already substituted for
-
- = (addOneToIdEnv env_so_far rhs_id (ValBinder new_rhs_id), Nothing)
- where
- maybe_rhs_id = case etaCoreExpr rhs of
- Var rhs_id -> Just rhs_id
- other -> Nothing
- Just rhs_id = maybe_rhs_id
- new_rhs_id = exported_binder `replaceIdInfo` getIdInfo rhs_id
- `replacePragmaInfo` getPragmaInfo rhs_id
- -- NB: we keep the Pragmas and IdInfo for the old rhs_id!
- -- This is important; it might be marked "no-inline" by
- -- the occurrence analyser (because it's recursive), and
- -- we must not lose that information.
-
- try_bind env_so_far bind
- = (env_so_far, Just bind)
\end{code}
Top level bindings
tidyCoreExpr body `thenTM` \ body' ->
returnTM (Lam (TyBinder tv') body')
-tidyCoreExpr (Lam (UsageBinder uv) body)
- = newUVar uv $ \ uv' ->
- tidyCoreExpr body `thenTM` \ body' ->
- returnTM (Lam (UsageBinder uv') body')
-
-- Try for let-to-case (see notes in Simplify.lhs for why
-- some let-to-case stuff is deferred to now).
tidyCoreExpr (Let (NonRec bndr rhs) body)
| willBeDemanded (getIdDemandInfo bndr) &&
+ not rhs_is_whnf && -- Don't do it if RHS is already in WHNF
typeOkForCase (idType bndr)
- = ASSERT( not (isPrimType (idType bndr)) )
+ = ASSERT( not (isUnpointedType (idType bndr)) )
tidyCoreExpr (Case rhs (AlgAlts [] (BindDefault bndr body)))
+ where
+ rhs_is_whnf = case mkFormSummary rhs of
+ VarForm -> True
+ ValueForm -> True
+ other -> False
tidyCoreExpr (Let (NonRec bndr rhs) body)
= tidyCoreExpr rhs `thenTM` \ rhs' ->
where
(bndrs, rhss) = unzip pairs
-tidyCoreExpr (SCC cc body)
+tidyCoreExpr (Note (Coerce to_ty from_ty) body)
= tidyCoreExprEta body `thenTM` \ body' ->
- returnTM (SCC cc body')
+ tidyTy to_ty `thenTM` \ to_ty' ->
+ tidyTy from_ty `thenTM` \ from_ty' ->
+ returnTM (Note (Coerce to_ty' from_ty') body')
-tidyCoreExpr (Coerce coercion ty body)
+tidyCoreExpr (Note note body)
= tidyCoreExprEta body `thenTM` \ body' ->
- tidyTy ty `thenTM` \ ty' ->
- returnTM (Coerce coercion ty' body')
+ returnTM (Note note body')
-- Wierd case for par, seq, fork etc. See notes above.
tidyCoreExpr (Case scrut@(Prim op args) (PrimAlts _ (BindDefault binder rhs)))
-- Eliminate polymorphic case, for which we can't generate code just yet
tidyCoreExpr (Case scrut (AlgAlts [] (BindDefault deflt_bndr rhs)))
| not (typeOkForCase (idType deflt_bndr))
- = pprTrace "Warning: discarding polymorphic case:" (ppr PprDebug scrut) $
+ = pprTrace "Warning: discarding polymorphic case:" (ppr scrut) $
case scrut of
Var v -> lookupId v `thenTM` \ v' ->
extendEnvTM deflt_bndr v' (tidyCoreExpr rhs)
tidyCoreArg (TyArg ty) = tidyTy ty `thenTM` \ ty' ->
returnTM (TyArg ty')
-tidyCoreArg (UsageArg u) = returnTM (UsageArg u)
\end{code}
\begin{code}
returnTM (rational_ty, Con ratio_data_con [TyArg integer_ty, num_arg, denom_arg])
where
(ratio_data_con, integer_ty)
- = case (maybeAppDataTyCon rational_ty) of
+ = case (splitAlgTyConApp_maybe rational_ty) of
Just (tycon, [i_ty], [con])
-> ASSERT(isIntegerTy i_ty && uniqueOf tycon == ratioTyConKey)
(con, i_ty)
\begin{code}
-- Need to extend the environment when we munge a binder, so that occurrences
--- of the binder will print the correct way (i.e. as a global not a local)
+-- of the binder will print the correct way (e.g. as a global not a local)
mungeTopBinder :: Id -> (Id -> TopTidyM a) -> TopTidyM a
mungeTopBinder id thing_inside mod env us
- = case lookupIdEnv env id of
- Just (ValBinder global) -> thing_inside global mod env us -- Already bound
-
- other -> -- Give it a new print-name unless it's an exported thing
- -- setNameVisibility also does the local/global thing
- let
- (id', us') | isExported id = (id, us)
- | otherwise
- = (setIdVisibility (Just mod) us id,
- incrUnique us)
+ = -- Give it a new print-name unless it's an exported thing
+ -- setNameVisibility also does the local/global thing
+ let
+ (id1, us') | isExported id = (id, us)
+ | otherwise
+ = (setIdVisibility (Just mod) us id,
+ incrUnique us)
+
+ -- Tidy the Id's SpecEnv
+ spec_env = getIdSpecialisation id
+ id2 | isEmptySpecEnv spec_env = id1
+ | otherwise = setIdSpecialisation id1 (tidySpecEnv env spec_env)
+
+ new_env = addToUFM env id (ValBinder id2)
+ in
+ thing_inside id2 mod new_env us'
- new_env = addToUFM env id (ValBinder id')
- in
- thing_inside id' mod new_env us'
+tidySpecEnv env spec_env
+ = substSpecEnv
+ emptyTyVarEnv -- Top level only
+ (tidy_spec_rhs env)
+ spec_env
+ where
+ -- tidy_spec_rhs is another horrid little hacked-up function for
+ -- the RHS of specialisation templates.
+ -- It assumes there is no type substitution.
+ --
+ -- See also SimplVar.substSpecEnvRhs Urgh
+ tidy_spec_rhs env (Var v) = case lookupUFM env v of
+ Just (ValBinder v') -> Var v'
+ Nothing -> Var v
+ tidy_spec_rhs env (App f (VarArg v)) = App (tidy_spec_rhs env f) (case lookupUFM env v of
+ Just (ValBinder v') -> VarArg v'
+ Nothing -> VarArg v)
+ tidy_spec_rhs env (App f arg) = App (tidy_spec_rhs env f) arg
+ tidy_spec_rhs env (Lam b e) = Lam b (tidy_spec_rhs env' e)
+ where
+ env' = case b of
+ ValBinder id -> delFromUFM env id
+ TyBinder _ -> env
mungeTopBinders [] k = k []
mungeTopBinders (b:bs) k = mungeTopBinder b $ \ b' ->
= let
-- Give the Id a fresh print-name, *and* rename its type
local_uniq' = incrUnique local_uniq
- rn_id = setIdVisibility Nothing local_uniq id
- id' = apply_to_Id (nmbr_ty env local_uniq') rn_id
+ name' = setNameVisibility Nothing local_uniq (getName id)
+ ty' = nmbr_ty env local_uniq' (idType id)
+ id' = mkUserId name' ty'
+ -- NB: This throws away the IdInfo of the Id, which we
+ -- no longer need. That means we don't need to
+ -- run over it with env, nor renumber it
+ --
+ -- NB: the Id's unique remains unchanged; it's only
+ -- its print name that is affected by local_uniq
+
env' = addToUFM env id (ValBinder id')
in
thing_inside id' mod env' (gus, local_uniq', floats)
env' = addToUFM env tyvar (TyBinder tyvar')
in
thing_inside tyvar' mod env' (gus, local_uniq', floats)
-
-newUVar uvar thing_inside mod env (gus, local_uniq, floats)
- = let
- local_uniq' = incrUnique local_uniq
- uvar' = cloneUVar uvar local_uniq
- env' = addToUFM env uvar (UsageBinder uvar')
- in
- thing_inside uvar' mod env' (gus, local_uniq', floats)
\end{code}
Re-numbering types
-- This little impedance-matcher calls nmbrType with the right arguments
nmbr_ty env uniq ty
- = nmbrType tv_env u_env uniq ty
+ = nmbrType tv_env uniq ty
where
tv_env :: TyVar -> TyVar
tv_env tyvar = case lookupUFM env tyvar of
Just (TyBinder tyvar') -> tyvar'
other -> tyvar
-
- u_env :: UVar -> UVar
- u_env uvar = case lookupUFM env uvar of
- Just (UsageBinder uvar') -> uvar'
- other -> uvar
\end{code}
projects / ghc-hetmet.git / blobdiff