%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[SimplCore]{Driver for simplifying @Core@ programs}
#include "HsVersions.h"
-import AnalFBWW ( analFBWW )
-import Bag ( isEmptyBag, foldBag )
-import BinderInfo ( BinderInfo{-instance Outputable-} )
-import CmdLineOpts ( CoreToDo(..), SimplifierSwitch(..), switchIsOn,
- opt_D_show_passes,
- opt_D_simplifier_stats,
- opt_D_dump_simpl,
+import CmdLineOpts ( CoreToDo(..), SimplifierSwitch(..),
+ SwitchResult(..), switchIsOn, intSwitchSet,
+ opt_D_dump_occur_anal, opt_D_dump_rules,
+ opt_D_dump_simpl_iterations,
+ opt_D_dump_simpl_stats,
+ opt_D_dump_simpl, opt_D_dump_rules,
opt_D_verbose_core2core,
- opt_DoCoreLinting,
- opt_FoldrBuildOn,
- opt_ReportWhyUnfoldingsDisallowed,
- opt_ShowImportSpecs,
- opt_LiberateCaseThreshold
+ opt_D_dump_occur_anal,
+ opt_UsageSPOn,
)
-import CoreLint ( lintCoreBindings )
+import CoreLint ( beginPass, endPass )
import CoreSyn
-import CoreUtils ( coreExprType )
-import SimplUtils ( etaCoreExpr, typeOkForCase )
+import CSE ( cseProgram )
+import Rules ( RuleBase, ProtoCoreRule(..), pprProtoCoreRule, prepareRuleBase, orphanRule )
import CoreUnfold
-import Literal ( Literal(..), literalType, mkMachInt )
-import ErrUtils ( ghcExit, dumpIfSet, doIfSet )
-import FiniteMap ( FiniteMap, emptyFM )
+import PprCore ( pprCoreBindings )
+import OccurAnal ( occurAnalyseBinds )
+import CoreUtils ( exprIsTrivial, coreExprType )
+import Simplify ( simplTopBinds, simplExpr )
+import SimplUtils ( etaCoreExpr, findDefault, simplBinders )
+import SimplMonad
+import Const ( Con(..), Literal(..), literalType, mkMachInt )
+import ErrUtils ( dumpIfSet )
import FloatIn ( floatInwards )
import FloatOut ( floatOutwards )
-import FoldrBuildWW ( mkFoldrBuildWW )
-import Id ( mkSysLocal, mkUserId, setIdVisibility, replaceIdInfo,
- replacePragmaInfo, getIdDemandInfo, idType,
- getIdInfo, getPragmaInfo, mkIdWithNewUniq,
- nullIdEnv, addOneToIdEnv, delOneFromIdEnv,
- lookupIdEnv, IdEnv,
- Id
+import Id ( Id, mkSysLocal, mkVanillaId, isBottomingId,
+ idType, setIdType, idName, idInfo, setIdNoDiscard
)
-import IdInfo ( willBeDemanded, DemandInfo )
-import Name ( isExported, isLocallyDefined,
- isLocalName, uniqToOccName,
- setNameVisibility,
- Module, NamedThing(..), OccName(..)
+import VarEnv
+import VarSet
+import Module ( Module )
+import Name ( mkLocalName, tidyOccName, tidyTopName,
+ NamedThing(..), OccName
)
-import TyCon ( TyCon )
+import TyCon ( TyCon, isDataTyCon )
import PrimOp ( PrimOp(..) )
-import PrelVals ( unpackCStringId, unpackCString2Id,
- integerZeroId, integerPlusOneId,
- integerPlusTwoId, integerMinusOneId
+import PrelInfo ( unpackCStringId, unpackCString2Id, addr2IntegerId )
+import Type ( Type, splitAlgTyConApp_maybe,
+ isUnLiftedType,
+ tidyType, tidyTypes, tidyTopType, tidyTyVar, tidyTyVars,
+ Type
)
-import Type ( splitAlgTyConApp_maybe, isUnpointedType, Type )
-import TysWiredIn ( stringTy, isIntegerTy )
+import TysWiredIn ( smallIntegerDataCon, isIntegerTy )
import LiberateCase ( liberateCase )
-import MagicUFs ( MagicUnfoldingFun )
-import PprCore
-import PprType ( GenType{-instance Outputable-}, GenTyVar{-ditto-},
- nmbrType
- )
import SAT ( doStaticArgs )
-import SimplMonad ( zeroSimplCount, showSimplCount, SimplCount )
-import SimplPgm ( simplifyPgm )
-import Specialise
-import SpecUtils ( pprSpecErrs )
-import StrictAnal ( saWwTopBinds )
-import TyVar ( TyVar, nameTyVar )
-import Unique ( Unique{-instance Eq-}, Uniquable(..),
- integerTyConKey, ratioTyConKey,
- mkUnique, incrUnique,
- initTidyUniques
- )
-import UniqSupply ( UniqSupply, mkSplitUniqSupply,
- splitUniqSupply, getUnique
+import Specialise ( specProgram)
+import UsageSPInf ( doUsageSPInf )
+import StrictAnal ( saBinds )
+import WorkWrap ( wwTopBinds )
+import CprAnalyse ( cprAnalyse )
+
+import Unique ( Unique, Uniquable(..),
+ ratioTyConKey
)
-import UniqFM ( UniqFM, lookupUFM, addToUFM )
+import UniqSupply ( UniqSupply, mkSplitUniqSupply, splitUniqSupply, uniqFromSupply )
+import Constants ( tARGET_MIN_INT, tARGET_MAX_INT )
import Util ( mapAccumL )
import SrcLoc ( noSrcLoc )
-import Constants ( tARGET_MIN_INT, tARGET_MAX_INT )
import Bag
import Maybes
import IO ( hPutStr, stderr )
import Outputable
+
+import Ratio ( numerator, denominator )
\end{code}
+%************************************************************************
+%* *
+\subsection{The driver for the simplifier}
+%* *
+%************************************************************************
+
\begin{code}
-core2core :: [CoreToDo] -- spec of what core-to-core passes to do
- -> FAST_STRING -- module name (profiling only)
- -> UniqSupply -- a name supply
- -> [TyCon] -- local data tycons and tycon specialisations
- -> [CoreBinding] -- input...
- -> IO [CoreBinding] -- results: program
-
-core2core core_todos module_name us local_tycons binds
- = -- Do the main business
- foldl_mn do_core_pass
- (binds, us, zeroSimplCount)
- core_todos
- >>= \ (processed_binds, us', simpl_stats) ->
-
- -- Do the final tidy-up
- let
- final_binds = tidyCorePgm module_name processed_binds
- in
- lintCoreBindings "TidyCorePgm" True final_binds >>
-
-
- -- Dump output
- dumpIfSet (opt_D_dump_simpl || opt_D_verbose_core2core)
- "Core transformations"
- (pprCoreBindings final_binds) >>
-
- -- Report statistics
- doIfSet opt_D_simplifier_stats
- (hPutStr stderr ("\nSimplifier Stats:\n") >>
- hPutStr stderr (showSimplCount simpl_stats) >>
- hPutStr stderr "\n") >>
+core2core :: [CoreToDo] -- Spec of what core-to-core passes to do
+ -> [CoreBind] -- Binds in
+ -> [ProtoCoreRule] -- Rules
+ -> IO ([CoreBind], [ProtoCoreRule])
+
+core2core core_todos binds rules
+ = do
+ us <- mkSplitUniqSupply 's'
+ let (cp_us, us1) = splitUniqSupply us
+ (ru_us, ps_us) = splitUniqSupply us1
+
+ better_rules <- simplRules ru_us rules binds
+
+ let (binds1, rule_base) = prepareRuleBase binds better_rules
+
+ -- Do the main business
+ (stats, processed_binds) <- doCorePasses zeroSimplCount cp_us binds1
+ rule_base core_todos
+
+ dumpIfSet opt_D_dump_simpl_stats
+ "Grand total simplifier statistics"
+ (pprSimplCount stats)
+
+ -- Do the post-simplification business
+ post_simpl_binds <- doPostSimplification ps_us processed_binds
-- Return results
- return final_binds
- where
- --------------
- do_core_pass info@(binds, us, simpl_stats) to_do =
- case (splitUniqSupply us) of
- (us1,us2) ->
- case to_do of
- CoreDoSimplify simpl_sw_chkr
- -> _scc_ "CoreSimplify"
- begin_pass ("Simplify" ++ if switchIsOn simpl_sw_chkr SimplDoFoldrBuild
- then " (foldr/build)" else "") >>
- case (simplifyPgm binds simpl_sw_chkr simpl_stats us1) of
- (p, it_cnt, simpl_stats2)
- -> end_pass us2 p simpl_stats2
- ("Simplify (" ++ show it_cnt ++ ")"
- ++ if switchIsOn simpl_sw_chkr SimplDoFoldrBuild
- then " foldr/build" else "")
-
- CoreDoFoldrBuildWorkerWrapper
- -> _scc_ "CoreDoFoldrBuildWorkerWrapper"
- begin_pass "FBWW" >>
- case (mkFoldrBuildWW us1 binds) of { binds2 ->
- end_pass us2 binds2 simpl_stats "FBWW" }
-
- CoreDoFoldrBuildWWAnal
- -> _scc_ "CoreDoFoldrBuildWWAnal"
- begin_pass "AnalFBWW" >>
- case (analFBWW binds) of { binds2 ->
- end_pass us2 binds2 simpl_stats "AnalFBWW" }
-
- CoreLiberateCase
- -> _scc_ "LiberateCase"
- begin_pass "LiberateCase" >>
- case (liberateCase opt_LiberateCaseThreshold binds) of { binds2 ->
- end_pass us2 binds2 simpl_stats "LiberateCase" }
-
- CoreDoFloatInwards
- -> _scc_ "FloatInwards"
- begin_pass "FloatIn" >>
- case (floatInwards binds) of { binds2 ->
- end_pass us2 binds2 simpl_stats "FloatIn" }
-
- CoreDoFullLaziness
- -> _scc_ "CoreFloating"
- begin_pass "FloatOut" >>
- case (floatOutwards us1 binds) of { binds2 ->
- end_pass us2 binds2 simpl_stats "FloatOut" }
-
- CoreDoStaticArgs
- -> _scc_ "CoreStaticArgs"
- begin_pass "StaticArgs" >>
- case (doStaticArgs binds us1) of { binds2 ->
- 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])
-
- CoreDoStrictness
- -> _scc_ "CoreStranal"
- begin_pass "StrAnal" >>
- case (saWwTopBinds us1 binds) of { binds2 ->
- end_pass us2 binds2 simpl_stats "StrAnal" }
-
- CoreDoSpecialising
- -> _scc_ "Specialise"
- begin_pass "Specialise" >>
- case (specProgram us1 binds) of { p ->
- end_pass us2 p simpl_stats "Specialise"
- }
-
- CoreDoPrintCore -- print result of last pass
- -> dumpIfSet (not opt_D_verbose_core2core) "Print Core"
- (pprCoreBindings binds) >>
- return (binds, us1, simpl_stats)
-
- -------------------------------------------------
-
- begin_pass what
- = if opt_D_show_passes
- then hPutStr stderr ("*** Core2Core: "++what++"\n")
- else return ()
-
- end_pass us2 binds2
- simpl_stats2 what
- = -- Report verbosely, if required
- dumpIfSet opt_D_verbose_core2core what
- (pprCoreBindings 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
- simpl_stats2 -- accumulated simplifier stats
- )
-
-
--- here so it can be inlined...
-foldl_mn f z [] = return z
-foldl_mn f z (x:xs) = f z x >>= \ zz ->
- foldl_mn f zz xs
+ return (post_simpl_binds, filter orphanRule better_rules)
+
+
+doCorePasses stats us binds irs []
+ = return (stats, binds)
+
+doCorePasses stats us binds irs (to_do : to_dos)
+ = do
+ let (us1, us2) = splitUniqSupply us
+ (stats1, binds1) <- doCorePass us1 binds irs to_do
+ doCorePasses (stats `plusSimplCount` stats1) us2 binds1 irs to_dos
+
+doCorePass us binds rb (CoreDoSimplify sw_chkr) = _scc_ "Simplify" simplifyPgm rb sw_chkr us binds
+doCorePass us binds rb CoreCSE = _scc_ "CommonSubExpr" noStats (cseProgram binds)
+doCorePass us binds rb CoreLiberateCase = _scc_ "LiberateCase" noStats (liberateCase binds)
+doCorePass us binds rb CoreDoFloatInwards = _scc_ "FloatInwards" noStats (floatInwards binds)
+doCorePass us binds rb CoreDoFullLaziness = _scc_ "FloatOutwards" noStats (floatOutwards us binds)
+doCorePass us binds rb CoreDoStaticArgs = _scc_ "StaticArgs" noStats (doStaticArgs us binds)
+doCorePass us binds rb CoreDoStrictness = _scc_ "Stranal" noStats (saBinds binds)
+doCorePass us binds rb CoreDoWorkerWrapper = _scc_ "WorkWrap" noStats (wwTopBinds us binds)
+doCorePass us binds rb CoreDoSpecialising = _scc_ "Specialise" noStats (specProgram us binds)
+doCorePass us binds rb CoreDoCPResult = _scc_ "CPResult" noStats (cprAnalyse binds)
+doCorePass us binds rb CoreDoPrintCore = _scc_ "PrintCore" noStats (printCore binds)
+doCorePass us binds rb CoreDoUSPInf
+ = _scc_ "CoreUsageSPInf"
+ if opt_UsageSPOn then
+ noStats (doUsageSPInf us binds)
+ else
+ trace "WARNING: ignoring requested -fusagesp pass; requires -fusagesp-on" $
+ noStats (return binds)
+
+printCore binds = do dumpIfSet True "Print Core"
+ (pprCoreBindings binds)
+ return binds
+
+noStats thing = do { result <- thing; return (zeroSimplCount, result) }
\end{code}
+%************************************************************************
+%* *
+\subsection{Dealing with rules}
+%* *
+%************************************************************************
+
+We must do some gentle simplifiation on the template (but not the RHS)
+of each rule. The case that forced me to add this was the fold/build rule,
+which without simplification looked like:
+ fold k z (build (/\a. g a)) ==> ...
+This doesn't match unless you do eta reduction on the build argument.
+
+\begin{code}
+simplRules :: UniqSupply -> [ProtoCoreRule] -> [CoreBind] -> IO [ProtoCoreRule]
+simplRules us rules binds
+ = do let (better_rules,_) = initSmpl sw_chkr us bind_vars black_list_all (mapSmpl simplRule rules)
+
+ dumpIfSet opt_D_dump_rules
+ "Transformation rules"
+ (vcat (map pprProtoCoreRule better_rules))
+
+ return better_rules
+ where
+ black_list_all v = True -- This stops all inlining
+ sw_chkr any = SwBool False -- A bit bogus
+
+ -- Boringly, we need to gather the in-scope set.
+ -- Typically this thunk won't even be force, but the test in
+ -- simpVar fails if it isn't right, and it might conceivably matter
+ bind_vars = foldr (unionVarSet . mkVarSet . bindersOf) emptyVarSet binds
+
+
+simplRule rule@(ProtoCoreRule is_local id (Rule name bndrs args rhs))
+ | not is_local
+ = returnSmpl rule -- No need to fiddle with imported rules
+ | otherwise
+ = simplBinders bndrs $ \ bndrs' ->
+ mapSmpl simplExpr args `thenSmpl` \ args' ->
+ simplExpr rhs `thenSmpl` \ rhs' ->
+ returnSmpl (ProtoCoreRule is_local id (Rule name bndrs' args' rhs'))
+\end{code}
%************************************************************************
%* *
-\subsection[SimplCore-indirections]{Eliminating indirections in Core code, and globalising}
+\subsection{The driver for the simplifier}
%* *
%************************************************************************
-Several tasks are done by @tidyCorePgm@
+\begin{code}
+simplifyPgm :: RuleBase
+ -> (SimplifierSwitch -> SwitchResult)
+ -> UniqSupply
+ -> [CoreBind] -- Input
+ -> IO (SimplCount, [CoreBind]) -- New bindings
+
+simplifyPgm (imported_rule_ids, rule_lhs_fvs)
+ sw_chkr us binds
+ = do {
+ beginPass "Simplify";
+
+ -- Glom all binds together in one Rec, in case any
+ -- transformations have introduced any new dependencies
+ --
+ -- NB: the global invariant is this:
+ -- *** the top level bindings are never cloned, and are always unique ***
+ --
+ -- We sort them into dependency order, but applying transformation rules may
+ -- make something at the top refer to something at the bottom:
+ -- f = \x -> p (q x)
+ -- h = \y -> 3
+ --
+ -- RULE: p (q x) = h x
+ --
+ -- Applying this rule makes f refer to h, although it doesn't appear to in the
+ -- source program. Our solution is to do this occasional glom-together step,
+ -- just once per overall simplfication step.
+
+ let { recd_binds = [Rec (flattenBinds binds)] };
+
+ (termination_msg, it_count, counts_out, binds') <- iteration us 1 zeroSimplCount recd_binds;
+
+ dumpIfSet (opt_D_verbose_core2core && opt_D_dump_simpl_stats)
+ "Simplifier statistics"
+ (vcat [text termination_msg <+> text "after" <+> ppr it_count <+> text "iterations",
+ text "",
+ pprSimplCount counts_out]);
+
+ endPass "Simplify"
+ (opt_D_verbose_core2core && not opt_D_dump_simpl_iterations)
+ binds' ;
+
+ return (counts_out, binds')
+ }
+ where
+ max_iterations = getSimplIntSwitch sw_chkr MaxSimplifierIterations
+ black_list_fn = blackListed rule_lhs_fvs (intSwitchSet sw_chkr SimplInlinePhase)
+
+ core_iter_dump binds | opt_D_verbose_core2core = pprCoreBindings binds
+ | otherwise = empty
+
+ iteration us iteration_no counts binds
+ = do {
+ -- Occurrence analysis
+ let { tagged_binds = _scc_ "OccAnal" occurAnalyseBinds binds } ;
+
+ dumpIfSet opt_D_dump_occur_anal "Occurrence analysis"
+ (pprCoreBindings tagged_binds);
+
+ -- Simplify
+ let { (binds', counts') = initSmpl sw_chkr us1 imported_rule_ids
+ black_list_fn
+ (simplTopBinds tagged_binds);
+ -- The imported_rule_ids are used by initSmpl to initialise
+ -- the in-scope set. That way, the simplifier will change any
+ -- occurrences of the imported id to the one in the imported_rule_ids
+ -- set, which are decorated with their rules.
+
+ all_counts = counts `plusSimplCount` counts'
+ } ;
+
+ -- Stop if nothing happened; don't dump output
+ if isZeroSimplCount counts' then
+ return ("Simplifier reached fixed point", iteration_no, all_counts, binds')
+ else do {
+
+ -- Dump the result of this iteration
+ dumpIfSet opt_D_dump_simpl_iterations
+ ("Simplifier iteration " ++ show iteration_no
+ ++ " out of " ++ show max_iterations)
+ (pprSimplCount counts') ;
+
+ if opt_D_dump_simpl_iterations then
+ endPass ("Simplifier iteration " ++ show iteration_no ++ " result")
+ opt_D_verbose_core2core
+ binds'
+ else
+ return [] ;
+
+ -- Stop if we've run out of iterations
+ if iteration_no == max_iterations then
+ do {
+#ifdef DEBUG
+ if max_iterations > 2 then
+ hPutStr stderr ("NOTE: Simplifier still going after " ++
+ show max_iterations ++
+ " iterations; bailing out.\n")
+ else
+#endif
+ return ();
+
+ return ("Simplifier baled out", iteration_no, all_counts, binds')
+ }
+
+ -- Else loop
+ else iteration us2 (iteration_no + 1) all_counts binds'
+ } }
+ where
+ (us1, us2) = splitUniqSupply us
+\end{code}
-----------------
- [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
- time
+%************************************************************************
+%* *
+\subsection{PostSimplification}
+%* *
+%************************************************************************
-3. Make the representation of NoRep literals explicit, and
- float their bindings to the top level
+Several tasks are performed by the post-simplification pass
+
+1. Make the representation of NoRep literals explicit, and
+ float their bindings to the top level. We only do the floating
+ part for NoRep lits inside a lambda (else no gain). We need to
+ take care with let x = "foo" in e
+ that we don't end up with a silly binding
+ let x = y in e
+ with a floated "foo". What a bore.
+
+4. Do eta reduction for lambda abstractions appearing in:
+ - the RHS of case alternatives
+ - the body of a let
+
+ These will otherwise turn into local bindings during Core->STG;
+ better to nuke them if possible. (In general the simplifier does
+ eta expansion not eta reduction, up to this point. It does eta
+ on the RHSs of bindings but not the RHSs of case alternatives and
+ let bodies)
+
+
+------------------- NOT DONE ANY MORE ------------------------
+[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
-4. Convert
+[Dec 98] [Not now done because there is no penalty in the code
+ generator for using the former form]
+2. Convert
case x of {...; x' -> ...x'...}
==>
case x of {...; _ -> ...x... }
See notes in SimplCase.lhs, near simplDefault for the reasoning here.
+--------------------------------------------------------------
-5. *Mangle* cases involving fork# and par# in the discriminant. The
- original templates for these primops (see @PrelVals.lhs@) constructed
- case expressions with boolean results solely to fool the strictness
- analyzer, the simplifier, and anyone else who might want to fool with
- the evaluation order. At this point in the compiler our evaluation
- order is safe. Therefore, we convert expressions of the form:
+Special case
+~~~~~~~~~~~~
- case par# e of
- True -> rhs
- False -> parError#
- ==>
- case par# e of
- _ -> rhs
+NOT ENABLED AT THE MOMENT (because the floated Ids are global-ish
+things, and we need local Ids for non-floated stuff):
-6. Eliminate polymorphic case expressions. We can't generate code for them yet.
+ Don't float stuff out of a binder that's marked as a bottoming Id.
+ Reason: it doesn't do any good, and creates more CAFs that increase
+ the size of SRTs.
-7. Do eta reduction for lambda abstractions appearing in:
- - the RHS of case alternatives
- - the body of a let
- These will otherwise turn into local bindings during Core->STG; better to
- nuke them if possible. (In general the simplifier does eta expansion not
- eta reduction, up to this point.)
+eg.
-8. Do let-to-case. See notes in Simplify.lhs for why we defer let-to-case
- for multi-constructor types.
+ f = error "string"
-9. Give all binders a nice print-name. Their uniques aren't changed; rather we give
- them lexically unique occ-names, so that we can safely print the OccNae only
- in the interface file. [Bad idea to change the uniques, because the code
- generator makes global labels from the uniques for local thunks etc.]
+is translated to
+ f' = unpackCString# "string"
+ f = error f'
+hence f' and f become CAFs. Instead, the special case for
+tidyTopBinding below makes sure this comes out as
+ f = let f' = unpackCString# "string" in error f'
+
+and we can safely ignore f as a CAF, since it can only ever be entered once.
-\begin{code}
-tidyCorePgm :: Module -> [CoreBinding] -> [CoreBinding]
-tidyCorePgm mod binds_in
- = initTM mod nullIdEnv $
- tidyTopBindings binds_in `thenTM` \ binds ->
- returnTM (bagToList binds)
-\end{code}
-Top level bindings
-~~~~~~~~~~~~~~~~~~
\begin{code}
-tidyTopBindings [] = returnTM emptyBag
-tidyTopBindings (b:bs)
- = tidyTopBinding b $
- tidyTopBindings bs
-
-tidyTopBinding :: CoreBinding
- -> TopTidyM (Bag CoreBinding)
- -> TopTidyM (Bag CoreBinding)
-
-tidyTopBinding (NonRec bndr rhs) thing_inside
- = initNestedTM (tidyCoreExpr rhs) `thenTM` \ (rhs',floats) ->
- mungeTopBinder bndr $ \ bndr' ->
- thing_inside `thenTM` \ binds ->
- returnTM ((floats `snocBag` NonRec bndr' rhs') `unionBags` binds)
-
-tidyTopBinding (Rec pairs) thing_inside
- = mungeTopBinders binders $ \ binders' ->
- initNestedTM (mapTM tidyCoreExpr rhss) `thenTM` \ (rhss', floats) ->
- thing_inside `thenTM` \ binds_inside ->
- returnTM ((floats `snocBag` Rec (binders' `zip` rhss')) `unionBags` binds_inside)
+doPostSimplification :: UniqSupply -> [CoreBind] -> IO [CoreBind]
+doPostSimplification us binds_in
+ = do
+ beginPass "Post-simplification pass"
+ let binds_out = initPM us (postSimplTopBinds binds_in)
+ endPass "Post-simplification pass" opt_D_verbose_core2core binds_out
+
+postSimplTopBinds :: [CoreBind] -> PostM [CoreBind]
+postSimplTopBinds binds
+ = mapPM postSimplTopBind binds `thenPM` \ binds' ->
+ returnPM (bagToList (unionManyBags binds'))
+
+postSimplTopBind :: CoreBind -> PostM (Bag CoreBind)
+postSimplTopBind (NonRec bndr rhs)
+ | isBottomingId bndr -- Don't lift out floats for bottoming Ids
+ -- See notes above
+ = getFloatsPM (postSimplExpr rhs) `thenPM` \ (rhs', floats) ->
+ returnPM (unitBag (NonRec bndr (foldrBag Let rhs' floats)))
+
+postSimplTopBind bind
+ = getFloatsPM (postSimplBind bind) `thenPM` \ (bind', floats) ->
+ returnPM (floats `snocBag` bind')
+
+postSimplBind (NonRec bndr rhs)
+ = postSimplExpr rhs `thenPM` \ rhs' ->
+ returnPM (NonRec bndr rhs')
+
+postSimplBind (Rec pairs)
+ = mapPM postSimplExpr rhss `thenPM` \ rhss' ->
+ returnPM (Rec (bndrs `zip` rhss'))
where
- (binders, rhss) = unzip pairs
+ (bndrs, rhss) = unzip pairs
\end{code}
-
Expressions
~~~~~~~~~~~
\begin{code}
-tidyCoreExpr (Var v) = lookupId v `thenTM` \ v' ->
- returnTM (Var v')
-
-tidyCoreExpr (Lit lit)
- = litToRep lit `thenTM` \ (_, lit_expr) ->
- returnTM lit_expr
-
-tidyCoreExpr (App fun arg)
- = tidyCoreExpr fun `thenTM` \ fun' ->
- tidyCoreArg arg `thenTM` \ arg' ->
- returnTM (App fun' arg')
-
-tidyCoreExpr (Con con args)
- = mapTM tidyCoreArg args `thenTM` \ args' ->
- returnTM (Con con args')
-
-tidyCoreExpr (Prim prim args)
- = tidyPrimOp prim `thenTM` \ prim' ->
- mapTM tidyCoreArg args `thenTM` \ args' ->
- returnTM (Prim prim' args')
-
-tidyCoreExpr (Lam (ValBinder v) body)
- = newId v $ \ v' ->
- tidyCoreExpr body `thenTM` \ body' ->
- returnTM (Lam (ValBinder v') body')
-
-tidyCoreExpr (Lam (TyBinder tv) body)
- = newTyVar tv $ \ tv' ->
- tidyCoreExpr body `thenTM` \ body' ->
- returnTM (Lam (TyBinder tv') 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 (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' ->
- newId bndr $ \ bndr' ->
- tidyCoreExprEta body `thenTM` \ body' ->
- returnTM (Let (NonRec bndr' rhs') body')
-
-tidyCoreExpr (Let (Rec pairs) body)
- = newIds bndrs $ \ bndrs' ->
- mapTM tidyCoreExpr rhss `thenTM` \ rhss' ->
- tidyCoreExprEta body `thenTM` \ body' ->
- returnTM (Let (Rec (bndrs' `zip` rhss')) body')
- where
- (bndrs, rhss) = unzip pairs
-
-tidyCoreExpr (SCC cc body)
- = tidyCoreExprEta body `thenTM` \ body' ->
- returnTM (SCC cc body')
-
-tidyCoreExpr (Coerce coercion ty body)
- = tidyCoreExprEta body `thenTM` \ body' ->
- tidyTy ty `thenTM` \ ty' ->
- returnTM (Coerce coercion ty' body')
-
--- Wierd case for par, seq, fork etc. See notes above.
-tidyCoreExpr (Case scrut@(Prim op args) (PrimAlts _ (BindDefault binder rhs)))
- | funnyParallelOp op
- = tidyCoreExpr scrut `thenTM` \ scrut' ->
- newId binder $ \ binder' ->
- tidyCoreExprEta rhs `thenTM` \ rhs' ->
- returnTM (Case scrut' (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 scrut) $
- case scrut of
- Var v -> lookupId v `thenTM` \ v' ->
- extendEnvTM deflt_bndr v' (tidyCoreExpr rhs)
- other -> tidyCoreExpr (Let (NonRec deflt_bndr scrut) rhs)
-
-tidyCoreExpr (Case scrut alts)
- = tidyCoreExpr scrut `thenTM` \ scrut' ->
- tidy_alts scrut' alts `thenTM` \ alts' ->
- returnTM (Case scrut' alts')
+postSimplExpr (Var v) = returnPM (Var v)
+postSimplExpr (Type ty) = returnPM (Type ty)
+
+postSimplExpr (App fun arg)
+ = postSimplExpr fun `thenPM` \ fun' ->
+ postSimplExpr arg `thenPM` \ arg' ->
+ returnPM (App fun' arg')
+
+postSimplExpr (Con (Literal lit) args)
+ = ASSERT( null args )
+ litToRep lit `thenPM` \ (lit_ty, lit_expr) ->
+ getInsideLambda `thenPM` \ in_lam ->
+ if in_lam && not (exprIsTrivial lit_expr) then
+ -- It must have been a no-rep literal with a
+ -- non-trivial representation; and we're inside a lambda;
+ -- so float it to the top
+ addTopFloat lit_ty lit_expr `thenPM` \ v ->
+ returnPM (Var v)
+ else
+ returnPM lit_expr
+
+postSimplExpr (Con con args)
+ = mapPM postSimplExpr args `thenPM` \ args' ->
+ returnPM (Con con args')
+
+postSimplExpr (Lam bndr body)
+ = insideLambda bndr $
+ postSimplExpr body `thenPM` \ body' ->
+ returnPM (Lam bndr body')
+
+postSimplExpr (Let bind body)
+ = postSimplBind bind `thenPM` \ bind' ->
+ postSimplExprEta body `thenPM` \ body' ->
+ returnPM (Let bind' body')
+
+postSimplExpr (Note note body)
+ = postSimplExpr body `thenPM` \ body' ->
+ -- Do *not* call postSimplExprEta here
+ -- We don't want to turn f = \x -> coerce t (\y -> f x y)
+ -- into f = \x -> coerce t (f x)
+ -- because then f has a lower arity.
+ -- This is not only bad in general, it causes the arity to
+ -- not match the [Demand] on an Id,
+ -- which confuses the importer of this module.
+ returnPM (Note note body')
+
+postSimplExpr (Case scrut case_bndr alts)
+ = postSimplExpr scrut `thenPM` \ scrut' ->
+ mapPM ps_alt alts `thenPM` \ alts' ->
+ returnPM (Case scrut' case_bndr alts')
where
- tidy_alts scrut (AlgAlts alts deflt)
- = mapTM tidy_alg_alt alts `thenTM` \ alts' ->
- tidy_deflt scrut deflt `thenTM` \ deflt' ->
- returnTM (AlgAlts alts' deflt')
-
- tidy_alts scrut (PrimAlts alts deflt)
- = mapTM tidy_prim_alt alts `thenTM` \ alts' ->
- tidy_deflt scrut deflt `thenTM` \ deflt' ->
- returnTM (PrimAlts alts' deflt')
-
- tidy_alg_alt (con,bndrs,rhs) = newIds bndrs $ \ bndrs' ->
- tidyCoreExprEta rhs `thenTM` \ rhs' ->
- returnTM (con, bndrs', rhs')
-
- tidy_prim_alt (lit,rhs) = tidyCoreExprEta rhs `thenTM` \ rhs' ->
- returnTM (lit,rhs')
-
- -- We convert case x of {...; x' -> ...x'...}
- -- to
- -- case x of {...; _ -> ...x... }
- --
- -- See notes in SimplCase.lhs, near simplDefault for the reasoning.
- -- It's quite easily done: simply extend the environment to bind the
- -- default binder to the scrutinee.
-
- tidy_deflt scrut NoDefault = returnTM NoDefault
- tidy_deflt scrut (BindDefault bndr rhs)
- = newId bndr $ \ bndr' ->
- extend_env (tidyCoreExprEta rhs) `thenTM` \ rhs' ->
- returnTM (BindDefault bndr' rhs')
- where
- extend_env = case scrut of
- Var v -> extendEnvTM bndr v
- other -> \x -> x
-
-tidyCoreExprEta e = tidyCoreExpr e `thenTM` \ e' ->
- returnTM (etaCoreExpr e')
-\end{code}
+ ps_alt (con,bndrs,rhs) = postSimplExprEta rhs `thenPM` \ rhs' ->
+ returnPM (con, bndrs, rhs')
-Arguments
-~~~~~~~~~
-\begin{code}
-tidyCoreArg :: CoreArg -> NestTidyM CoreArg
-
-tidyCoreArg (VarArg v)
- = lookupId v `thenTM` \ v' ->
- returnTM (VarArg v')
-
-tidyCoreArg (LitArg lit)
- = litToRep lit `thenTM` \ (lit_ty, lit_expr) ->
- case lit_expr of
- Var v -> returnTM (VarArg v)
- Lit l -> returnTM (LitArg l)
- other -> addTopFloat lit_ty lit_expr `thenTM` \ v ->
- returnTM (VarArg v)
-
-tidyCoreArg (TyArg ty) = tidyTy ty `thenTM` \ ty' ->
- returnTM (TyArg ty')
+postSimplExprEta e = postSimplExpr e `thenPM` \ e' ->
+ returnPM (etaCoreExpr e')
\end{code}
-\begin{code}
-tidyPrimOp (CCallOp fn casm gc tys ty)
- = mapTM tidyTy tys `thenTM` \ tys' ->
- tidyTy ty `thenTM` \ ty' ->
- returnTM (CCallOp fn casm gc tys' ty')
-
-tidyPrimOp other_prim_op = returnTM other_prim_op
-\end{code}
-
%************************************************************************
%* *
binding out to the top level.
\begin{code}
-
-litToRep :: Literal -> NestTidyM (Type, CoreExpr)
+litToRep :: Literal -> PostM (Type, CoreExpr)
-litToRep (NoRepStr s)
- = returnTM (stringTy, rhs)
+litToRep (NoRepStr s ty)
+ = returnPM (ty, rhs)
where
rhs = if (any is_NUL (_UNPK_ s))
then -- Must cater for NULs in literal string
- mkGenApp (Var unpackCString2Id)
- [LitArg (MachStr s),
- LitArg (mkMachInt (toInteger (_LENGTH_ s)))]
+ mkApps (Var unpackCString2Id)
+ [mkLit (MachStr s),
+ mkLit (mkMachInt (toInteger (_LENGTH_ s)))]
else -- No NULs in the string
- App (Var unpackCStringId) (LitArg (MachStr s))
+ App (Var unpackCStringId) (mkLit (MachStr s))
is_NUL c = c == '\0'
\end{code}
If an Integer is small enough (Haskell implementations must support
Ints in the range $[-2^29+1, 2^29-1]$), wrap it up in @int2Integer@;
-otherwise, wrap with @litString2Integer@.
+otherwise, wrap with @addr2Integer@.
\begin{code}
litToRep (NoRepInteger i integer_ty)
- = returnTM (integer_ty, rhs)
+ = returnPM (integer_ty, rhs)
where
- rhs | i == 0 = Var integerZeroId -- Extremely convenient to look out for
- | i == 1 = Var integerPlusOneId -- a few very common Integer literals!
- | i == 2 = Var integerPlusTwoId
- | i == (-1) = Var integerMinusOneId
-
- | i > tARGET_MIN_INT && -- Small enough, so start from an Int
+ rhs | i > tARGET_MIN_INT && -- Small enough, so start from an Int
i < tARGET_MAX_INT
- = Prim Int2IntegerOp [LitArg (mkMachInt i)]
+ = Con (DataCon smallIntegerDataCon) [Con (Literal (mkMachInt i)) []]
| otherwise -- Big, so start from a string
- = Prim Addr2IntegerOp [LitArg (MachStr (_PK_ (show i)))]
+ = App (Var addr2IntegerId) (Con (Literal (MachStr (_PK_ (show i)))) [])
litToRep (NoRepRational r rational_ty)
- = tidyCoreArg (LitArg (NoRepInteger (numerator r) integer_ty)) `thenTM` \ num_arg ->
- tidyCoreArg (LitArg (NoRepInteger (denominator r) integer_ty)) `thenTM` \ denom_arg ->
- returnTM (rational_ty, Con ratio_data_con [TyArg integer_ty, num_arg, denom_arg])
+ = postSimplExpr (mkLit (NoRepInteger (numerator r) integer_ty)) `thenPM` \ num_arg ->
+ postSimplExpr (mkLit (NoRepInteger (denominator r) integer_ty)) `thenPM` \ denom_arg ->
+ returnPM (rational_ty, mkConApp ratio_data_con [Type integer_ty, num_arg, denom_arg])
where
(ratio_data_con, integer_ty)
= case (splitAlgTyConApp_maybe rational_ty) of
Just (tycon, [i_ty], [con])
- -> ASSERT(isIntegerTy i_ty && uniqueOf tycon == ratioTyConKey)
+ -> ASSERT(isIntegerTy i_ty && getUnique tycon == ratioTyConKey)
(con, i_ty)
_ -> (panic "ratio_data_con", panic "integer_ty")
-litToRep other_lit = returnTM (literalType other_lit, Lit other_lit)
+litToRep other_lit = returnPM (literalType other_lit, mkLit other_lit)
\end{code}
-\begin{code}
-funnyParallelOp SeqOp = True
-funnyParallelOp ParOp = True
-funnyParallelOp ForkOp = True
-funnyParallelOp _ = False
-\end{code}
-
%************************************************************************
%* *
%************************************************************************
\begin{code}
-type TidyM a state = Module
- -> UniqFM CoreBinder -- Maps Ids to Ids, TyVars to TyVars etc
- -> state
- -> (a, state)
-
-type TopTidyM a = TidyM a Unique
-type NestTidyM a = TidyM a (Unique, -- Global names
- Unique, -- Local names
- Bag CoreBinding) -- Floats
-
-
-(initialTopTidyUnique, initialNestedTidyUnique) = initTidyUniques
+type PostM a = Bool -- True <=> inside a *value* lambda
+ -> (UniqSupply, Bag CoreBind) -- Unique supply and Floats in
+ -> (a, (UniqSupply, Bag CoreBind))
-initTM :: Module -> UniqFM CoreBinder -> TopTidyM a -> a
-initTM mod env m
- = case m mod env initialTopTidyUnique of
+initPM :: UniqSupply -> PostM a -> a
+initPM us m
+ = case m False {- not inside lambda -} (us, emptyBag) of
(result, _) -> result
-initNestedTM :: NestTidyM a -> TopTidyM (a, Bag CoreBinding)
-initNestedTM m mod env global_us
- = case m mod env (global_us, initialNestedTidyUnique, emptyBag) of
- (result, (global_us', _, floats)) -> ((result, floats), global_us')
+returnPM v in_lam usf = (v, usf)
+thenPM m k in_lam usf = case m in_lam usf of
+ (r, usf') -> k r in_lam usf'
-returnTM v mod env usf = (v, usf)
-thenTM m k mod env usf = case m mod env usf of
- (r, usf') -> k r mod env usf'
+mapPM f [] = returnPM []
+mapPM f (x:xs) = f x `thenPM` \ r ->
+ mapPM f xs `thenPM` \ rs ->
+ returnPM (r:rs)
-mapTM f [] = returnTM []
-mapTM f (x:xs) = f x `thenTM` \ r ->
- mapTM f xs `thenTM` \ rs ->
- returnTM (r:rs)
-\end{code}
+insideLambda :: CoreBndr -> PostM a -> PostM a
+insideLambda bndr m in_lam usf | isId bndr = m True usf
+ | otherwise = m in_lam usf
+getInsideLambda :: PostM Bool
+getInsideLambda in_lam usf = (in_lam, usf)
-\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)
-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)
-
- new_env = addToUFM env id (ValBinder id')
- in
- thing_inside id' mod new_env us'
-
-mungeTopBinders [] k = k []
-mungeTopBinders (b:bs) k = mungeTopBinder b $ \ b' ->
- mungeTopBinders bs $ \ bs' ->
- k (b' : bs')
-
-addTopFloat :: Type -> CoreExpr -> NestTidyM Id
-addTopFloat lit_ty lit_rhs mod env (gus, lus, floats)
+getFloatsPM :: PostM a -> PostM (a, Bag CoreBind)
+getFloatsPM m in_lam (us, floats)
= let
- gus' = incrUnique gus
- lit_local = mkSysLocal SLIT("lit") gus lit_ty noSrcLoc
- lit_id = setIdVisibility (Just mod) gus lit_local
- in
- (lit_id, (gus', lus, floats `snocBag` NonRec lit_id lit_rhs))
-
-lookupId :: Id -> TidyM Id state
-lookupId v mod env usf
- = case lookupUFM env v of
- Nothing -> (v, usf)
- Just (ValBinder v') -> (v', usf)
-
-extendEnvTM :: Id -> Id -> (TidyM a state) -> TidyM a state
-extendEnvTM v v' m mod env usf
- = m mod (addOneToIdEnv env v (ValBinder v')) usf
-\end{code}
-
-
-Making new local binders
-~~~~~~~~~~~~~~~~~~~~~~~~
-\begin{code}
-newId id thing_inside mod env (gus, local_uniq, floats)
- = let
- -- Give the Id a fresh print-name, *and* rename its type
- local_uniq' = incrUnique local_uniq
- 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')
+ (a, (us', floats')) = m in_lam (us, emptyBag)
in
- thing_inside id' mod env' (gus, local_uniq', floats)
-
-newIds [] thing_inside
- = thing_inside []
-newIds (bndr:bndrs) thing_inside
- = newId bndr $ \ bndr' ->
- newIds bndrs $ \ bndrs' ->
- thing_inside (bndr' : bndrs')
+ ((a, floats'), (us', floats))
-
-newTyVar tyvar thing_inside mod env (gus, local_uniq, floats)
+addTopFloat :: Type -> CoreExpr -> PostM Id
+addTopFloat lit_ty lit_rhs in_lam (us, floats)
= let
- local_uniq' = incrUnique local_uniq
- tyvar' = nameTyVar tyvar (uniqToOccName local_uniq)
- env' = addToUFM env tyvar (TyBinder tyvar')
+ (us1, us2) = splitUniqSupply us
+ uniq = uniqFromSupply us1
+ lit_id = mkSysLocal SLIT("lf") uniq lit_ty
in
- thing_inside tyvar' mod env' (gus, local_uniq', floats)
-\end{code}
-
-Re-numbering types
-~~~~~~~~~~~~~~~~~~
-\begin{code}
-tidyTy ty mod env usf@(_, local_uniq, _)
- = (nmbr_ty env local_uniq ty, usf)
- -- We can use local_uniq as a base for renaming forall'd variables
- -- in the type; we don't need to know how many are consumed.
-
--- This little impedance-matcher calls nmbrType with the right arguments
-nmbr_ty 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
+ (lit_id, (us2, floats `snocBag` NonRec lit_id lit_rhs))
\end{code}