X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FsimplCore%2FSimplCore.lhs;h=0576ab219ebcfb96516fe755cdf0968c9bf7ac9c;hb=438596897ebbe25a07e1c82085cfbc5bdb00f09e;hp=1c99c714a2016c3c2134fed9b3d86cd0bc7a1c77;hpb=7d61cb61daa5e433a0cb85b34b7f0c58b2f961ff;p=ghc-hetmet.git diff --git a/ghc/compiler/simplCore/SimplCore.lhs b/ghc/compiler/simplCore/SimplCore.lhs index 1c99c71..0576ab2 100644 --- a/ghc/compiler/simplCore/SimplCore.lhs +++ b/ghc/compiler/simplCore/SimplCore.lhs @@ -1,592 +1,726 @@ % -% (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} \begin{code} -#include "HsVersions.h" - module SimplCore ( core2core ) where -import Ubiq{-uitous-} +#include "HsVersions.h" -import AnalFBWW ( analFBWW ) -import Bag ( isEmptyBag, foldBag ) -import BinderInfo ( BinderInfo{-instance Outputable-} ) -import CgCompInfo ( uNFOLDING_CREATION_THRESHOLD, - uNFOLDING_USE_THRESHOLD, - uNFOLDING_OVERRIDE_THRESHOLD, - uNFOLDING_CON_DISCOUNT_WEIGHT - ) -import CmdLineOpts ( CoreToDo(..), SimplifierSwitch(..), switchIsOn, - opt_D_show_passes, +import CmdLineOpts ( CoreToDo(..), SimplifierSwitch(..), + SwitchResult, switchIsOn, + opt_D_dump_occur_anal, + opt_D_dump_simpl_iterations, opt_D_simplifier_stats, + opt_D_dump_simpl, opt_D_verbose_core2core, - opt_DoCoreLinting, - opt_FoldrBuildOn, - opt_ReportWhyUnfoldingsDisallowed, - opt_ShowImportSpecs, - opt_UnfoldingCreationThreshold, - opt_UnfoldingOverrideThreshold, - opt_UnfoldingUseThreshold + opt_D_dump_occur_anal ) -import CoreLint ( lintCoreBindings ) +import CoreLint ( beginPass, endPass ) import CoreSyn +import PprCore ( pprCoreBindings ) +import OccurAnal ( occurAnalyseBinds ) +import CoreUtils ( exprIsTrivial, coreExprType ) +import Simplify ( simplBind ) +import SimplUtils ( etaCoreExpr, findDefault ) +import SimplMonad import CoreUnfold -import CoreUtils ( substCoreBindings, manifestlyWHNF ) +import Const ( Con(..), Literal(..), literalType, mkMachInt ) +import ErrUtils ( dumpIfSet ) import FloatIn ( floatInwards ) import FloatOut ( floatOutwards ) -import FoldrBuildWW ( mkFoldrBuildWW ) -import Id ( idType, toplevelishId, idWantsToBeINLINEd, - unfoldingUnfriendlyId, - nullIdEnv, addOneToIdEnv, delOneFromIdEnv, - lookupIdEnv, IdEnv(..), - GenId{-instance Outputable-} +import Id ( Id, mkSysLocal, mkUserId, + setIdVisibility, setIdUnfolding, + getIdSpecialisation, setIdSpecialisation, + getInlinePragma, setInlinePragma, + idType, setIdType ) -import IdInfo ( mkUnfolding ) -import LiberateCase ( liberateCase ) -import MagicUFs ( MagicUnfoldingFun ) -import MainMonad ( writeMn, exitMn, thenMn, thenMn_, returnMn, - MainIO(..) +import IdInfo ( InlinePragInfo(..) ) +import VarEnv +import VarSet +import Name ( isExported, mkSysLocalName, + Module, NamedThing(..), OccName(..) + ) +import TyCon ( TyCon, isDataTyCon ) +import PrimOp ( PrimOp(..) ) +import PrelInfo ( unpackCStringId, unpackCString2Id, + integerZeroId, integerPlusOneId, + integerPlusTwoId, integerMinusOneId, + int2IntegerId, addr2IntegerId ) -import Maybes ( maybeToBool ) -import Outputable ( Outputable(..){-instance * (,) -} ) -import PprCore ( pprCoreBinding, GenCoreExpr{-instance Outputable-} ) -import PprStyle ( PprStyle(..) ) -import PprType ( GenType{-instance Outputable-}, GenTyVar{-ditto-} ) -import Pretty ( ppShow, ppAboves, ppAbove, ppCat, ppStr ) +import Type ( Type, splitAlgTyConApp_maybe, + isUnLiftedType, mkTyVarTy, Type ) +import TysWiredIn ( isIntegerTy ) +import LiberateCase ( liberateCase ) +import PprType ( nmbrType ) import SAT ( doStaticArgs ) -import SCCauto ( addAutoCostCentres ) -import SimplMonad ( zeroSimplCount, showSimplCount, SimplCount ) -import SimplPgm ( simplifyPgm ) -import SimplVar ( leastItCouldCost ) -import Specialise -import SpecUtils ( pprSpecErrs ) +import Specialise ( specProgram) +import SpecEnv ( specEnvToList, specEnvFromList ) import StrictAnal ( saWwTopBinds ) -import TyVar ( nullTyVarEnv, GenTyVar{-instance Eq-} ) -import Unique ( Unique{-instance Eq-} ) -import UniqSupply ( splitUniqSupply ) -import Util ( panic{-ToDo:rm-} ) - -#if ! OMIT_DEFORESTER -import Deforest ( deforestProgram ) -import DefUtils ( deforestable ) -#endif - -isWrapperFor = panic "SimplCore.isWrapperFor (ToDo)" -isWrapperId = panic "SimplCore.isWrapperId (ToDo)" +import Var ( TyVar, setTyVarName ) +import Unique ( Unique, Uniquable(..), + ratioTyConKey, mkUnique, incrUnique, initTidyUniques + ) +import UniqSupply ( UniqSupply, splitUniqSupply ) +import Constants ( tARGET_MIN_INT, tARGET_MAX_INT ) +import Bag +import Maybes +import IO ( hPutStr, stderr ) +import Outputable +\end{code} + +\begin{code} +core2core :: [CoreToDo] -- Spec of what core-to-core passes to do + -> FAST_STRING -- Module name (profiling only) + -> UniqSupply -- A name supply + -> [CoreBind] -- Input + -> IO [CoreBind] -- Result + +core2core core_todos module_name us binds + = do + -- Do the main business + processed_binds <- doCorePasses us binds core_todos + + -- Do the final tidy-up + final_binds <- tidyCorePgm module_name processed_binds + + -- Return results + return final_binds + +doCorePasses us binds [] + = return binds + +doCorePasses us binds (to_do : to_dos) + = do + let (us1, us2) = splitUniqSupply us + binds1 <- doCorePass us1 binds to_do + doCorePasses us2 binds1 to_dos + +doCorePass us binds (CoreDoSimplify sw_chkr) = _scc_ "Simplify" simplifyPgm sw_chkr us binds +doCorePass us binds CoreLiberateCase = _scc_ "LiberateCase" liberateCase binds +doCorePass us binds CoreDoFloatInwards = _scc_ "FloatInwards" floatInwards binds +doCorePass us binds CoreDoFullLaziness = _scc_ "CoreFloating" floatOutwards us binds +doCorePass us binds CoreDoStaticArgs = _scc_ "CoreStaticArgs" doStaticArgs us binds +doCorePass us binds CoreDoStrictness = _scc_ "CoreStranal" saWwTopBinds us binds +doCorePass us binds CoreDoSpecialising = _scc_ "Specialise" specProgram us binds +\end{code} + + +%************************************************************************ +%* * +\subsection{The driver for the simplifier} +%* * +%************************************************************************ + +\begin{code} +simplifyPgm :: (SimplifierSwitch -> SwitchResult) + -> UniqSupply + -> [CoreBind] -- Input + -> IO [CoreBind] -- New bindings + +simplifyPgm sw_chkr us binds + = do { + beginPass "Simplify"; + + (termination_msg, it_count, counts, binds') <- iteration us 1 zeroSimplCount binds; + + dumpIfSet opt_D_simplifier_stats "Simplifier statistics" + (vcat [text termination_msg <+> text "after" <+> ppr it_count <+> text "iterations", + text "", + pprSimplCount counts]); + + endPass "Simplify" + (opt_D_verbose_core2core && not opt_D_dump_simpl_iterations) + binds' + } + where + max_iterations = getSimplIntSwitch sw_chkr MaxSimplifierIterations + simpl_switch_is_on = switchIsOn sw_chkr + + 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 simpl_switch_is_on binds }; + dumpIfSet opt_D_dump_occur_anal "Occurrence analysis" + (pprCoreBindings tagged_binds); + + -- Simplify + let { (binds', counts') = initSmpl sw_chkr us1 (simplTopBinds tagged_binds); + 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) + (vcat[pprSimplCount counts', + text "", + core_iter_dump binds']) ; + + -- Stop if we've run out of iterations + if iteration_no == max_iterations then + do { + if max_iterations > 1 then + hPutStr stderr ("NOTE: Simplifier still going after " ++ + show max_iterations ++ + " iterations; bailing out.\n") + else 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 + + +simplTopBinds [] = returnSmpl [] +simplTopBinds (bind1 : binds) = (simplBind bind1 $ + simplTopBinds binds) `thenSmpl` \ (binds1', binds') -> + returnSmpl (binds1' ++ binds') +\end{code} + + +%************************************************************************ +%* * +\subsection[SimplCore-indirections]{Eliminating indirections in Core code, and globalising} +%* * +%************************************************************************ + +Several tasks are done by @tidyCorePgm@ + +---------------- + [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 + +3. 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. 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 par# in the discriminant. The unfolding + for par in PrelConc.lhs include case expressions with integer + 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: + + case par# e of + 0# -> rhs + _ -> parError# + ==> + case par# e of + _ -> rhs + + fork# isn't handled like this - it's an explicit IO operation now. + The reason is that fork# returns a ThreadId#, which gets in the + way of the above scheme. And anyway, IO is the only guaranteed + way to enforce ordering --SDM. + +6. Mangle cases involving seq# in the discriminant. Up to this + point, seq# will appear like this: + + case seq# e of + 0# -> seqError# + _ -> ... + + where the 0# branch is purely to bamboozle the strictness analyser + (see case 5 above). This code comes from an unfolding for 'seq' + in Prelude.hs. We translate this into + + case e of + _ -> ... + + Now that the evaluation order is safe. The code generator knows + how to push a seq frame on the stack if 'e' is of function type, + or is polymorphic. + + +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.) + +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.] + + +Special case +~~~~~~~~~~~~ + +NOT ENABLED AT THE MOMENT (because the floated Ids are global-ish +things, and we need local Ids for non-floated stuff): + + 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. + +eg. + + f = error "string" + +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 -> [CoreBind] -> IO [CoreBind] + +tidyCorePgm mod binds_in + = do + beginPass "Tidy Core" + + let binds_out = bagToList (initTM mod (tidyTopBindings binds_in)) + + endPass "Tidy Core" (opt_D_dump_simpl || opt_D_verbose_core2core) binds_out \end{code} +Top level bindings +~~~~~~~~~~~~~~~~~~ \begin{code} -core2core :: [CoreToDo] -- spec of what core-to-core passes to do - -> FAST_STRING -- module name (profiling only) - -> PprStyle -- printing style (for debugging only) - -> UniqSupply -- a name supply - -> [TyCon] -- local data tycons and tycon specialisations - -> FiniteMap TyCon [(Bool, [Maybe Type])] - -> [CoreBinding] -- input... - -> MainIO - ([CoreBinding], -- results: program, plus... - IdEnv UnfoldingDetails, -- unfoldings to be exported from here - SpecialiseData) -- specialisation data - -core2core core_todos module_name ppr_style us local_tycons tycon_specs binds - = BSCC("Core2Core") - if null core_todos then -- very rare, I suspect... - -- well, we still must do some renumbering - returnMn ( - (substCoreBindings nullIdEnv nullTyVarEnv binds us, - nullIdEnv, - init_specdata) - ) +tidyTopBindings [] = returnTM emptyBag +tidyTopBindings (b:bs) + = tidyTopBinding b $ + tidyTopBindings bs + +tidyTopBinding :: CoreBind + -> TopTidyM (Bag CoreBind) + -> TopTidyM (Bag CoreBind) + +tidyTopBinding (NonRec bndr rhs) thing_inside + = initNestedTM (tidyCoreExpr rhs) `thenTM` \ (rhs',floats) -> + tidyTopBinder bndr $ \ bndr' -> + thing_inside `thenTM` \ binds -> + let + this_bind {- | isBottomingId bndr + = unitBag (NonRec bndr' (foldrBag Let rhs' floats)) + | otherwise -} + = floats `snocBag` NonRec bndr' rhs' + in + returnTM (this_bind `unionBags` binds) + +tidyTopBinding (Rec pairs) thing_inside + = tidyTopBinders binders $ \ binders' -> + initNestedTM (mapTM tidyCoreExpr rhss) `thenTM` \ (rhss', floats) -> + thing_inside `thenTM` \ binds_inside -> + returnTM ((floats `snocBag` Rec (binders' `zip` rhss')) `unionBags` binds_inside) + where + (binders, rhss) = unzip pairs +\end{code} + +\begin{code} +tidyTopBinder :: Id -> (Id -> TopTidyM (Bag CoreBind)) -> TopTidyM (Bag CoreBind) +tidyTopBinder id thing_inside + = mungeTopBndr id $ \ id' -> + let + spec_items = specEnvToList (getIdSpecialisation id') + in + if null spec_items then + + -- Common case, no specialisations to tidy + thing_inside id' + else + + -- Oh well, tidy those specialisations + initNestedTM (mapTM tidySpecItem spec_items) `thenTM` \ (spec_items', floats) -> + let + id'' = setIdSpecialisation id' (specEnvFromList spec_items') + in + extendEnvTM id (Var id'') $ + thing_inside id'' `thenTM` \ binds -> + returnTM (floats `unionBags` binds) + +tidyTopBinders [] k = k [] +tidyTopBinders (b:bs) k = tidyTopBinder b $ \ b' -> + tidyTopBinders bs $ \ bs' -> + k (b' : bs') + +tidySpecItem (tyvars, tys, rhs) + = newBndrs tyvars $ \ tyvars' -> + mapTM tidyTy tys `thenTM` \ tys' -> + tidyCoreExpr rhs `thenTM` \ rhs' -> + returnTM (tyvars', tys', rhs') +\end{code} + +Expressions +~~~~~~~~~~~ +\begin{code} +tidyCoreExpr (Var v) = lookupId v + +tidyCoreExpr (Type ty) + = tidyTy ty `thenTM` \ ty' -> + returnTM (Type ty') + +tidyCoreExpr (App fun arg) + = tidyCoreExpr fun `thenTM` \ fun' -> + tidyCoreExpr arg `thenTM` \ arg' -> + returnTM (App fun' arg') + +tidyCoreExpr (Con (Literal lit) args) + = ASSERT( null args ) + litToRep lit `thenTM` \ (lit_ty, lit_expr) -> + getInsideLambda `thenTM` \ 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 `thenTM` \ v -> + returnTM (Var v) else - (if do_verbose_core2core then - writeMn stderr "VERBOSE CORE-TO-CORE:\n" - else returnMn ()) `thenMn_` - - -- better do the main business - foldl_mn do_core_pass - (binds, us, nullIdEnv, init_specdata, zeroSimplCount) - core_todos - `thenMn` \ (processed_binds, _, inline_env, spec_data, simpl_stats) -> - - (if opt_D_simplifier_stats - then writeMn stderr ("\nSimplifier Stats:\n") - `thenMn_` - writeMn stderr (showSimplCount simpl_stats) - `thenMn_` - writeMn stderr "\n" - else returnMn () - ) `thenMn_` - - returnMn (processed_binds, inline_env, spec_data) - ESCC + returnTM lit_expr + +tidyCoreExpr (Con con args) + = mapTM tidyCoreExpr args `thenTM` \ args' -> + returnTM (Con con args') + +tidyCoreExpr (Lam bndr body) + = newBndr bndr $ \ bndr' -> + insideLambda bndr $ + tidyCoreExpr body `thenTM` \ body' -> + returnTM (Lam bndr' body') + +tidyCoreExpr (Let (NonRec bndr rhs) body) + = tidyCoreExpr rhs `thenTM` \ rhs' -> + tidyBindNonRec bndr rhs' body + +tidyCoreExpr (Let (Rec pairs) body) + = newBndrs bndrs $ \ bndrs' -> + mapTM tidyCoreExpr rhss `thenTM` \ rhss' -> + tidyCoreExprEta body `thenTM` \ body' -> + returnTM (Let (Rec (bndrs' `zip` rhss')) body') + where + (bndrs, rhss) = unzip pairs + +tidyCoreExpr (Note (Coerce to_ty from_ty) body) + = tidyCoreExprEta body `thenTM` \ body' -> + tidyTy to_ty `thenTM` \ to_ty' -> + tidyTy from_ty `thenTM` \ from_ty' -> + returnTM (Note (Coerce to_ty' from_ty') body') + +tidyCoreExpr (Note note body) + = tidyCoreExprEta body `thenTM` \ body' -> + returnTM (Note note body') + +-- seq#: see notes above. +tidyCoreExpr (Case scrut@(Con (PrimOp SeqOp) [Type _, e]) bndr alts) + = tidyCoreExpr e `thenTM` \ e' -> + newBndr bndr $ \ bndr' -> + let new_bndr = setIdType bndr' (coreExprType e') in + tidyCoreExprEta default_rhs `thenTM` \ rhs' -> + returnTM (Case e' new_bndr [(DEFAULT,[],rhs')]) where - init_specdata = initSpecData local_tycons tycon_specs - - do_verbose_core2core = opt_D_verbose_core2core - - lib_case_threshold -- ToDo: HACK HACK HACK : FIX ME FIX ME FIX ME - -- Use 4x a known threshold - = case opt_UnfoldingOverrideThreshold of - Nothing -> 4 * uNFOLDING_USE_THRESHOLD - Just xx -> 4 * xx - - ------------- - core_linter = if opt_DoCoreLinting - then lintCoreBindings ppr_style - else ( \ whodunnit spec_done binds -> binds ) - - -------------- - do_core_pass info@(binds, us, inline_env, spec_data, simpl_stats) to_do - = let - (us1, us2) = splitUniqSupply us - in - case to_do of - CoreDoSimplify simpl_sw_chkr - -> BSCC("CoreSimplify") - begin_pass ("Simplify" ++ if switchIsOn simpl_sw_chkr SimplDoFoldrBuild - then " (foldr/build)" else "") `thenMn_` - case (simplifyPgm binds simpl_sw_chkr simpl_stats us1) of - (p, it_cnt, simpl_stats2) - -> end_pass False us2 p inline_env spec_data simpl_stats2 - ("Simplify (" ++ show it_cnt ++ ")" - ++ if switchIsOn simpl_sw_chkr SimplDoFoldrBuild - then " foldr/build" else "") - ESCC - - CoreDoFoldrBuildWorkerWrapper - -> BSCC("CoreDoFoldrBuildWorkerWrapper") - begin_pass "FBWW" `thenMn_` - case (mkFoldrBuildWW us1 binds) of { binds2 -> - end_pass False us2 binds2 inline_env spec_data simpl_stats "FBWW" - } ESCC - - CoreDoFoldrBuildWWAnal - -> BSCC("CoreDoFoldrBuildWWAnal") - begin_pass "AnalFBWW" `thenMn_` - case (analFBWW binds) of { binds2 -> - end_pass False us2 binds2 inline_env spec_data simpl_stats "AnalFBWW" - } ESCC - - CoreLiberateCase - -> BSCC("LiberateCase") - begin_pass "LiberateCase" `thenMn_` - case (liberateCase lib_case_threshold binds) of { binds2 -> - end_pass False us2 binds2 inline_env spec_data simpl_stats "LiberateCase" - } ESCC - - CoreDoCalcInlinings1 -- avoid inlinings w/ cost-centres - -> BSCC("CoreInlinings1") - begin_pass "CalcInlinings" `thenMn_` - case (calcInlinings False inline_env binds) of { inline_env2 -> - end_pass False us2 binds inline_env2 spec_data simpl_stats "CalcInlinings" - } ESCC - - CoreDoCalcInlinings2 -- allow inlinings w/ cost-centres - -> BSCC("CoreInlinings2") - begin_pass "CalcInlinings" `thenMn_` - case (calcInlinings True inline_env binds) of { inline_env2 -> - end_pass False us2 binds inline_env2 spec_data simpl_stats "CalcInlinings" - } ESCC - - CoreDoFloatInwards - -> BSCC("FloatInwards") - begin_pass "FloatIn" `thenMn_` - case (floatInwards binds) of { binds2 -> - end_pass False us2 binds2 inline_env spec_data simpl_stats "FloatIn" - } ESCC - - CoreDoFullLaziness - -> BSCC("CoreFloating") - begin_pass "FloatOut" `thenMn_` - case (floatOutwards us1 binds) of { binds2 -> - end_pass False us2 binds2 inline_env spec_data simpl_stats "FloatOut" - } ESCC - - CoreDoStaticArgs - -> BSCC("CoreStaticArgs") - begin_pass "StaticArgs" `thenMn_` - case (doStaticArgs binds us1) of { binds2 -> - end_pass False us2 binds2 inline_env spec_data 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]) - } ESCC - - CoreDoStrictness - -> BSCC("CoreStranal") - begin_pass "StrAnal" `thenMn_` - case (saWwTopBinds us1 binds) of { binds2 -> - end_pass False us2 binds2 inline_env spec_data simpl_stats "StrAnal" - } ESCC - - CoreDoSpecialising - -> BSCC("Specialise") - begin_pass "Specialise" `thenMn_` - 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 - (if not spec_noerrs || - (opt_ShowImportSpecs && not (isEmptyBag spec_warn)) then - writeMn stderr (ppShow 1000 {-pprCols-} - (pprSpecErrs module_name spec_errs spec_warn spec_tyerrs)) - `thenMn_` writeMn stderr "\n" - else - returnMn ()) `thenMn_` - - (if not spec_noerrs then -- Stop here if specialisation errors occured - exitMn 1 - else - returnMn ()) `thenMn_` - - end_pass False us2 p inline_env spec_data2 simpl_stats "Specialise" - } - ESCC - - CoreDoDeforest -#if OMIT_DEFORESTER - -> error "ERROR: CoreDoDeforest: not built into compiler\n" -#else - -> BSCC("Deforestation") - begin_pass "Deforestation" `thenMn_` - case (deforestProgram binds us1) of { binds2 -> - end_pass False us2 binds2 inline_env spec_data simpl_stats "Deforestation" - } - ESCC -#endif - - CoreDoAutoCostCentres - -> BSCC("AutoSCCs") - begin_pass "AutoSCCs" `thenMn_` - case (addAutoCostCentres module_name binds) of { binds2 -> - end_pass False us2 binds2 inline_env spec_data simpl_stats "AutoSCCs" - } - ESCC - - CoreDoPrintCore -- print result of last pass - -> end_pass True us2 binds inline_env spec_data simpl_stats "Print" - - - ------------------------------------------------- - - begin_pass - = if opt_D_show_passes - then \ what -> writeMn stderr ("*** Core2Core: "++what++"\n") - else \ what -> returnMn () - - end_pass print us2 binds2 inline_env2 - spec_data2@(SpecData spec_done _ _ _ _ _ _ _) - simpl_stats2 what - = -- report verbosely, if required - (if (do_verbose_core2core && not print) || - (print && not do_verbose_core2core) - then - writeMn stderr ("\n*** "++what++":\n") - `thenMn_` - writeMn stderr (ppShow 1000 - (ppAboves (map (pprCoreBinding ppr_style) binds2))) - `thenMn_` - writeMn stderr "\n" - else - returnMn ()) `thenMn_` - let - linted_binds = core_linter what spec_done binds2 - in - returnMn - (linted_binds, -- processed binds, possibly run thru CoreLint - us2, -- UniqueSupply for the next guy - inline_env2, -- possibly-updated inline env - spec_data2, -- possibly-updated specialisation info - simpl_stats2 -- accumulated simplifier stats - ) - --- here so it can be inlined... -foldl_mn f z [] = returnMn z -foldl_mn f z (x:xs) = f z x `thenMn` \ zz -> - foldl_mn f zz xs + (other_alts, maybe_default) = findDefault alts + Just default_rhs = maybe_default + +-- par#: see notes above. +tidyCoreExpr (Case scrut@(Con (PrimOp op) args) bndr alts) + | funnyParallelOp op && maybeToBool maybe_default + = tidyCoreExpr scrut `thenTM` \ scrut' -> + newBndr bndr $ \ bndr' -> + tidyCoreExprEta default_rhs `thenTM` \ rhs' -> + returnTM (Case scrut' bndr' [(DEFAULT,[],rhs')]) + where + (other_alts, maybe_default) = findDefault alts + Just default_rhs = maybe_default + +tidyCoreExpr (Case scrut case_bndr alts) + = tidyCoreExpr scrut `thenTM` \ scrut' -> + newBndr case_bndr $ \ case_bndr' -> + mapTM tidy_alt alts `thenTM` \ alts' -> + returnTM (Case scrut' case_bndr' alts') + where + tidy_alt (con,bndrs,rhs) = newBndrs bndrs $ \ bndrs' -> + tidyCoreExprEta rhs `thenTM` \ rhs' -> + returnTM (con, bndrs', rhs') + +tidyCoreExprEta e = tidyCoreExpr e `thenTM` \ e' -> + returnTM (etaCoreExpr e') + +tidyBindNonRec bndr val' body + | exprIsTrivial val' + = extendEnvTM bndr val' (tidyCoreExpr body) + + | otherwise + = newBndr bndr $ \ bndr' -> + tidyCoreExpr body `thenTM` \ body' -> + returnTM (Let (NonRec bndr' val') body') \end{code} ---- ToDo: maybe move elsewhere --- -For top-level, exported binders that either (a)~have been INLINEd by -the programmer or (b)~are sufficiently ``simple'' that they should be -inlined, we want to record this info in a suitable IdEnv. +%************************************************************************ +%* * +\subsection[coreToStg-lits]{Converting literals} +%* * +%************************************************************************ + +Literals: the NoRep kind need to be de-no-rep'd. +We always replace them with a simple variable, and float a suitable +binding out to the top level. + +\begin{code} + +litToRep :: Literal -> NestTidyM (Type, CoreExpr) -But: if something has a ``wrapper unfolding,'' we do NOT automatically -give it a regular unfolding (exception below). We usually assume its -worker will get a ``regular'' unfolding. We can then treat these two -levels of unfolding separately (we tend to be very friendly towards -wrapper unfoldings, for example), giving more fine-tuned control. +litToRep (NoRepStr s ty) + = returnTM (ty, rhs) + where + rhs = if (any is_NUL (_UNPK_ s)) + + then -- Must cater for NULs in literal string + mkApps (Var unpackCString2Id) + [mkLit (MachStr s), + mkLit (mkMachInt (toInteger (_LENGTH_ s)))] + + else -- No NULs in the string + 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@. + +\begin{code} +litToRep (NoRepInteger i integer_ty) + = returnTM (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 + i < tARGET_MAX_INT + = App (Var int2IntegerId) (Con (Literal (mkMachInt i)) []) + + | otherwise -- Big, so start from a string + = App (Var addr2IntegerId) (Con (Literal (MachStr (_PK_ (show i)))) []) + + +litToRep (NoRepRational r rational_ty) + = tidyCoreExpr (mkLit (NoRepInteger (numerator r) integer_ty)) `thenTM` \ num_arg -> + tidyCoreExpr (mkLit (NoRepInteger (denominator r) integer_ty)) `thenTM` \ denom_arg -> + returnTM (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 && getUnique tycon == ratioTyConKey) + (con, i_ty) + + _ -> (panic "ratio_data_con", panic "integer_ty") + +litToRep other_lit = returnTM (literalType other_lit, mkLit other_lit) +\end{code} + +\begin{code} +funnyParallelOp ParOp = True +funnyParallelOp _ = False +\end{code} -The exception is: If the ``regular unfolding'' mentions no other -global Ids (i.e., it's all PrimOps and cases and local Ids) then we -assume it must be really good and we take it anyway. -We also need to check that everything in the RHS (values and types) -will be visible on the other side of an interface, too. +%************************************************************************ +%* * +\subsection{The monad} +%* * +%************************************************************************ \begin{code} -calcInlinings :: Bool -- True => inlinings with _scc_s are OK - -> IdEnv UnfoldingDetails - -> [CoreBinding] - -> IdEnv UnfoldingDetails +type TidyM a state = Module + -> Bool -- True <=> inside a *value* lambda + -> (TyVarEnv Type, IdEnv CoreExpr, IdOrTyVarSet) + -- Substitution and in-scope binders + -> state + -> (a, state) -calcInlinings scc_s_OK inline_env_so_far top_binds +type TopTidyM a = TidyM a Unique +type NestTidyM a = TidyM a (Unique, -- Global names + Unique, -- Local names + Bag CoreBind) -- Floats + + +(initialTopTidyUnique, initialNestedTidyUnique) = initTidyUniques + +initTM :: Module -> TopTidyM a -> a +initTM mod m + = case m mod False {- not inside lambda -} empty_env initialTopTidyUnique of + (result, _) -> result + where + empty_env = (emptyVarEnv, emptyVarEnv, emptyVarSet) + +initNestedTM :: NestTidyM a -> TopTidyM (a, Bag CoreBind) +initNestedTM m mod in_lam env global_us + = case m mod in_lam env (global_us, initialNestedTidyUnique, emptyBag) of + (result, (global_us', _, floats)) -> ((result, floats), global_us') + +returnTM v mod in_lam env usf = (v, usf) +thenTM m k mod in_lam env usf = case m mod in_lam env usf of + (r, usf') -> k r mod in_lam env usf' + +mapTM f [] = returnTM [] +mapTM f (x:xs) = f x `thenTM` \ r -> + mapTM f xs `thenTM` \ rs -> + returnTM (r:rs) + +insideLambda :: CoreBndr -> NestTidyM a -> NestTidyM a +insideLambda bndr m mod in_lam env usf | isId bndr = m mod True env usf + | otherwise = m mod in_lam env usf + +getInsideLambda :: NestTidyM Bool +getInsideLambda mod in_lam env usf = (in_lam, usf) +\end{code} + +Need to extend the environment when we munge a binder, so that +occurrences of the binder will print the correct way (e.g. as a global +not a local). + +In cases where we don't clone the binder (because it's an exported +id), we still zap the unfolding and inline pragma info so that +unnecessary gumph isn't carried into the code generator. This fixes a +nasty space leak. + +\begin{code} +mungeTopBndr id thing_inside mod in_lam env@(ty_env, val_env, in_scope) us + = thing_inside id' mod in_lam (ty_env, val_env', in_scope') us' + where + (id', us') | isExported id = (zapSomeIdInfo id, us) + | otherwise = (zapSomeIdInfo (setIdVisibility (Just mod) us id), + incrUnique us) + val_env' = extendVarEnv val_env id (Var id') + in_scope' = extendVarSet in_scope id' + +zapSomeIdInfo id = id `setIdUnfolding` noUnfolding `setInlinePragma` new_ip + where new_ip = case getInlinePragma id of + ICanSafelyBeINLINEd _ _ -> NoInlinePragInfo + something_else -> something_else + +addTopFloat :: Type -> CoreExpr -> NestTidyM Id +addTopFloat lit_ty lit_rhs mod in_lam env (gus, lus, floats) = let - result = foldl calci inline_env_so_far top_binds + gus' = incrUnique gus + lit_local = mkSysLocal gus lit_ty + lit_id = setIdVisibility (Just mod) gus lit_local in - --pprTrace "inline env:\n" (ppAboves (map pp_item (getIdEnvMapping result))) - result - where - pp_item (binder, details) - = ppCat [ppr PprDebug binder, ppStr "=>", pp_det details] - where - pp_det NoUnfoldingDetails = ppStr "_N_" ---LATER: pp_det (IWantToBeINLINEd _) = ppStr "INLINE" - pp_det (GenForm _ _ expr guide) - = ppAbove (ppr PprDebug guide) (ppr PprDebug expr) - pp_det other = ppStr "???" - - ------------ - my_trace = if opt_ReportWhyUnfoldingsDisallowed - then trace - else \ msg stuff -> stuff - - (unfolding_creation_threshold, explicit_creation_threshold) - = case opt_UnfoldingCreationThreshold of - Nothing -> (uNFOLDING_CREATION_THRESHOLD, False) - Just xx -> (xx, True) - - unfold_use_threshold - = case opt_UnfoldingUseThreshold of - Nothing -> uNFOLDING_USE_THRESHOLD - Just xx -> xx - - unfold_override_threshold - = case opt_UnfoldingOverrideThreshold of - Nothing -> uNFOLDING_OVERRIDE_THRESHOLD - Just xx -> xx - - con_discount_weight = uNFOLDING_CON_DISCOUNT_WEIGHT - - calci inline_env (Rec pairs) - = foldl (calc True{-recursive-}) inline_env pairs - - calci inline_env bind@(NonRec binder rhs) - = calc False{-not recursive-} inline_env (binder, rhs) - - --------------------------------------- - - calc is_recursive inline_env (binder, rhs) - | not (toplevelishId binder) - = --pprTrace "giving up on not top-level:" (ppr PprDebug binder) - ignominious_defeat - - | rhs_mentions_an_unmentionable - || (not explicit_INLINE_requested - && (rhs_looks_like_a_caf || guidance_says_don't || guidance_size_too_big)) - = let - my_my_trace - = if explicit_INLINE_requested - && not (isWrapperId binder) -- these always claim to be INLINEd - && not have_inlining_already - then trace -- we'd better have a look... - else my_trace - - which = if scc_s_OK then " (late):" else " (early):" - in - my_my_trace ("unfolding disallowed for"++which++(ppShow 80 (ppr PprDebug binder))) ( - ignominious_defeat - ) - - | rhs `isWrapperFor` binder - -- Don't add an explicit "unfolding"; let the worker/wrapper - -- stuff do its thing. INLINE things don't get w/w'd, so - -- they will be OK. - = ignominious_defeat - -#if ! OMIT_DEFORESTER - -- For the deforester: bypass the barbed wire for recursive - -- functions that want to be inlined and are tagged deforestable - -- by the user, allowing these things to be communicated - -- across module boundaries. - - | is_recursive && - explicit_INLINE_requested && - deforestable binder && - scc_s_OK -- hack, only get them in - -- calc_inlinings2 - = glorious_success UnfoldAlways -#endif - - | is_recursive && not rhs_looks_like_a_data_val - -- The only recursive defns we are prepared to tolerate at the - -- moment is top-level very-obviously-a-data-value ones. - -- We *need* these for dictionaries to be exported! - = --pprTrace "giving up on rec:" (ppr PprDebug binder) - ignominious_defeat - - -- Not really interested unless it's exported, but doing it - -- this way (not worrying about export-ness) gets us all the - -- workers/specs, etc., too; which we will need for generating - -- interfaces. We are also not interested if this binder is - -- in the environment we already have (perhaps from a previous - -- run of calcInlinings -- "earlier" is presumed to mean - -- "better"). - - | explicit_INLINE_requested - = glorious_success UnfoldAlways - - | otherwise - = glorious_success guidance + (lit_id, (gus', lus, floats `snocBag` NonRec lit_id lit_rhs)) - where - guidance - = calcUnfoldingGuidance scc_s_OK max_out_threshold rhs - where - max_out_threshold = if explicit_INLINE_requested - then 100000 -- you asked for it, you got it - else unfolding_creation_threshold - - guidance_size - = case guidance of - UnfoldAlways -> 0 -- *extremely* small - EssentialUnfolding -> 0 -- ditto - UnfoldIfGoodArgs _ _ _ size -> size - - guidance_says_don't = case guidance of { UnfoldNever -> True; _ -> False } - - guidance_size_too_big - -- Does the guidance suggest that this unfolding will - -- be of no use *no matter* the arguments given to it? - -- Could be more sophisticated... - = case guidance of - UnfoldAlways -> False - EssentialUnfolding -> False - UnfoldIfGoodArgs _ no_val_args arg_info_vec size - - -> if explicit_creation_threshold then - False -- user set threshold; don't second-guess... - - else if no_val_args == 0 && rhs_looks_like_a_data_val then - False -- we'd like a top-level data constr to be - -- visible even if it is never unfolded - else - let - cost - = leastItCouldCost con_discount_weight size no_val_args - arg_info_vec rhs_arg_tys - in --- (if (unfold_use_threshold < cost) then (pprTrace "cost:" (ppInt cost)) else \x->x ) ( - unfold_use_threshold < cost --- ) - - - rhs_looks_like_a_caf = not (manifestlyWHNF rhs) - - rhs_looks_like_a_data_val - = case (collectBinders rhs) of - (_, _, [], Con _ _) -> True - other -> False - - rhs_arg_tys - = case (collectBinders rhs) of - (_, _, val_binders, _) -> map idType val_binders - - (mentioned_ids, _, _, mentions_litlit) - = mentionedInUnfolding (\x -> x) rhs - - rhs_mentions_an_unmentionable - = foldBag (||) unfoldingUnfriendlyId False mentioned_ids - || mentions_litlit - -- ToDo: probably need to chk tycons/classes... - - mentions_no_other_ids = isEmptyBag mentioned_ids - - explicit_INLINE_requested - -- did it come from a user {-# INLINE ... #-}? - -- (Warning: must avoid including wrappers.) - = idWantsToBeINLINEd binder - && not (rhs `isWrapperFor` binder) - - have_inlining_already = maybeToBool (lookupIdEnv inline_env binder) - - ignominious_defeat = inline_env -- just give back what we got - - {- - "glorious_success" is ours if we've found a suitable unfolding. - - But we check for a couple of fine points. - - (1) If this Id already has an inlining in the inline_env, - we don't automatically take it -- the earlier one is - "likely" to be better. - - But if the new one doesn't mention any other global - Ids, and it's pretty small (< UnfoldingOverrideThreshold), - then we take the chance that the new one *is* better. - - (2) If we have an Id w/ a worker/wrapper split (with - an unfolding for the wrapper), we tend to want to keep - it -- and *nuke* any inlining that we conjured up - earlier. - - But, again, if this unfolding doesn't mention any - other global Ids (and small enough), then it is - probably better than the worker/wrappery, so we take - it. - -} - glorious_success guidance - = let - new_env = addOneToIdEnv inline_env binder (mkUnfolding guidance rhs) - - foldr_building = opt_FoldrBuildOn - in - if (not have_inlining_already) then - -- Not in env: we take it no matter what - -- NB: we could check for worker/wrapper-ness, - -- but the truth is we probably haven't run - -- the strictness analyser yet. - new_env - - else if explicit_INLINE_requested then - -- If it was a user INLINE, then we know it's already - -- in the inline_env; we stick with what we already - -- have. - --pprTrace "giving up on INLINE:" (ppr PprDebug binder) - ignominious_defeat - - else if isWrapperId binder then - -- It's in the env, but we have since worker-wrapperised; - -- we either take this new one (because it's so good), - -- or we *undo* the one in the inline_env, so the - -- wrapper-inlining will take over. - - if mentions_no_other_ids {- *** && size <= unfold_override_threshold -} then - new_env - else - delOneFromIdEnv inline_env binder - - else - -- It's in the env, nothing to do w/ worker wrapper; - -- we'll take it if it is better. - - if not foldr_building -- ANDY hates us... (see below) - && mentions_no_other_ids - && guidance_size <= unfold_override_threshold then - new_env - else - --pprTrace "giving up on final hurdle:" (ppCat [ppr PprDebug binder, ppInt guidance_size, ppInt unfold_override_threshold]) - ignominious_defeat -- and at the last hurdle, too! +lookupId :: Id -> TidyM CoreExpr state +lookupId v mod in_lam (_, val_env, _) usf + = case lookupVarEnv val_env v of + Nothing -> (Var v, usf) + Just e -> (e, usf) + +extendEnvTM :: Id -> CoreExpr -> (TidyM a state) -> TidyM a state +extendEnvTM v e m mod in_lam (ty_env, val_env, in_scope) usf + = m mod in_lam (ty_env, extendVarEnv val_env v e, in_scope) usf \end{code} -ANDY, on the hatred of the check above; why obliterate it? Consider - head xs = foldr (\ x _ -> x) (_|_) xs +Making new local binders +~~~~~~~~~~~~~~~~~~~~~~~~ +\begin{code} +newBndr tyvar thing_inside mod in_lam (ty_env, val_env, in_scope) (gus, local_uniq, floats) + | isTyVar tyvar + = let + local_uniq' = incrUnique local_uniq + tyvar' = setTyVarName tyvar (mkSysLocalName local_uniq) + ty_env' = extendVarEnv ty_env tyvar (mkTyVarTy tyvar') + in_scope' = extendVarSet in_scope tyvar' + in + thing_inside tyvar' mod in_lam (ty_env', val_env, in_scope') (gus, local_uniq', floats) + +newBndr id thing_inside mod in_lam (ty_env, val_env, in_scope) (gus, local_uniq, floats) + | isId id + = let + -- Give the Id a fresh print-name, *and* rename its type + local_uniq' = incrUnique local_uniq + name' = mkSysLocalName local_uniq + ty' = nmbrType 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. + + val_env' = extendVarEnv val_env id (Var id') + in_scope' = extendVarSet in_scope id' + in + thing_inside id' mod in_lam (ty_env, val_env', in_scope') (gus, local_uniq', floats) + +newBndrs [] thing_inside + = thing_inside [] +newBndrs (bndr:bndrs) thing_inside + = newBndr bndr $ \ bndr' -> + newBndrs bndrs $ \ bndrs' -> + thing_inside (bndr' : bndrs') +\end{code} + +Re-numbering types +~~~~~~~~~~~~~~~~~~ +\begin{code} +tidyTy ty mod in_lam (ty_env, val_env, in_scope) usf@(_, local_uniq, _) + = (nmbrType 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. +\end{code} -This then is exported via a pragma. However, -*if* you include the extra code above, you will -export the non-foldr/build version. +-- Get rid of this function when we move to the new code generator. + +\begin{code} +typeOkForCase :: Type -> Bool +typeOkForCase ty + | isUnLiftedType ty -- Primitive case + = True + + | otherwise + = case (splitAlgTyConApp_maybe ty) of + Just (tycon, ty_args, []) -> False + Just (tycon, ty_args, non_null_data_cons) | isDataTyCon tycon -> True + other -> False + -- Null data cons => type is abstract, which code gen can't + -- currently handle. (ToDo: when return-in-heap is universal we + -- don't need to worry about this.) +\end{code}