X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FsimplCore%2FSimplCore.lhs;h=8a122ef9ba2259b4e2713f673cfa1380aaa52e9d;hb=b89ea7a599124f7d38500939eaf0f76874000657;hp=dffde6b86d62fc2d141fc9adfe877dd5c9494958;hpb=ca5a4a480d10d61e5b7a52eb4d556e8b8c33e69d;p=ghc-hetmet.git diff --git a/ghc/compiler/simplCore/SimplCore.lhs b/ghc/compiler/simplCore/SimplCore.lhs index dffde6b..8a122ef 100644 --- a/ghc/compiler/simplCore/SimplCore.lhs +++ b/ghc/compiler/simplCore/SimplCore.lhs @@ -8,137 +8,137 @@ module SimplCore ( core2core ) where -import Ubiq{-uitous-} +IMP_Ubiq(){-uitous-} +IMPORT_1_3(IO(hPutStr,stderr)) 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, 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_LiberateCaseThreshold ) import CoreLint ( lintCoreBindings ) import CoreSyn +import CoreUtils ( coreExprType ) +import SimplUtils ( etaCoreExpr, typeOkForCase ) import CoreUnfold -import CoreUtils ( substCoreBindings, manifestlyWHNF ) -import ErrUtils ( ghcExit ) +import Literal ( Literal(..), literalType, mkMachInt ) +import ErrUtils ( ghcExit, dumpIfSet, doIfSet ) +import FiniteMap ( FiniteMap ) import FloatIn ( floatInwards ) import FloatOut ( floatOutwards ) import FoldrBuildWW ( mkFoldrBuildWW ) -import Id ( idType, toplevelishId, idWantsToBeINLINEd, - unfoldingUnfriendlyId, +import Id ( mkSysLocal, setIdVisibility, replaceIdInfo, + replacePragmaInfo, getIdDemandInfo, idType, + getIdInfo, getPragmaInfo, mkIdWithNewUniq, nullIdEnv, addOneToIdEnv, delOneFromIdEnv, - lookupIdEnv, IdEnv(..), - GenId{-instance Outputable-} + lookupIdEnv, SYN_IE(IdEnv), omitIfaceSigForId, + apply_to_Id, + GenId{-instance Outputable-}, SYN_IE(Id) + ) +import IdInfo ( willBeDemanded, DemandInfo ) +import Name ( isExported, isLocallyDefined, + isLocalName, uniqToOccName, + SYN_IE(Module), NamedThing(..), OccName(..) + ) +import TyCon ( TyCon ) +import PrimOp ( PrimOp(..) ) +import PrelVals ( unpackCStringId, unpackCString2Id, + integerZeroId, integerPlusOneId, + integerPlusTwoId, integerMinusOneId ) -import IdInfo ( mkUnfolding ) +import Type ( maybeAppDataTyCon, isPrimType, SYN_IE(Type) ) +import TysWiredIn ( stringTy, isIntegerTy ) import LiberateCase ( liberateCase ) import MagicUFs ( MagicUnfoldingFun ) -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 Outputable ( pprDumpStyle, printErrs, + PprStyle(..), Outputable(..){-instance * (,) -} + ) +import PprCore +import PprType ( GenType{-instance Outputable-}, GenTyVar{-ditto-}, + nmbrType + ) +import Pretty ( Doc, vcat, ($$), hsep ) import SAT ( doStaticArgs ) -import SCCauto ( addAutoCostCentres ) import SimplMonad ( zeroSimplCount, showSimplCount, SimplCount ) import SimplPgm ( simplifyPgm ) -import SimplVar ( leastItCouldCost ) import Specialise import SpecUtils ( pprSpecErrs ) 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 TyVar ( SYN_IE(TyVar), nullTyVarEnv, GenTyVar{-instance Eq-}, + nameTyVar + ) +import Unique ( Unique{-instance Eq-}, Uniquable(..), + integerTyConKey, ratioTyConKey, + mkUnique, incrUnique, + initTidyUniques + ) +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 SrcLoc ( noSrcLoc ) +import Constants ( tARGET_MIN_INT, tARGET_MAX_INT ) +import Bag +import Maybes + \end{code} \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... -> IO - ([CoreBinding], -- results: program, plus... - IdEnv UnfoldingDetails, -- unfoldings to be exported from here + ([CoreBinding], -- results: program, plus... SpecialiseData) -- specialisation data -core2core core_todos module_name ppr_style us local_tycons tycon_specs binds - = _scc_ "Core2Core" - if null core_todos then -- very rare, I suspect... - -- well, we still must do some renumbering - return ( - (substCoreBindings nullIdEnv nullTyVarEnv binds us, - nullIdEnv, - init_specdata) - ) - else - (if do_verbose_core2core then - hPutStr stderr "VERBOSE CORE-TO-CORE:\n" - else return ()) >> - - -- better do the main business - foldl_mn do_core_pass - (binds, us, nullIdEnv, init_specdata, zeroSimplCount) +core2core core_todos module_name us local_tycons tycon_specs binds + = -- Do the main business + foldl_mn do_core_pass + (binds, us, init_specdata, zeroSimplCount) core_todos - >>= \ (processed_binds, _, inline_env, spec_data, simpl_stats) -> - - (if opt_D_simplifier_stats - then hPutStr stderr ("\nSimplifier Stats:\n") - >> - hPutStr stderr (showSimplCount simpl_stats) - >> - hPutStr stderr "\n" - else return () - ) >> - - return (processed_binds, inline_env, spec_data) - where - init_specdata = initSpecData local_tycons tycon_specs + >>= \ (processed_binds, us', spec_data, simpl_stats) -> + + -- Do the final tidy-up + let + final_binds = tidyCorePgm module_name processed_binds + in + lintCoreBindings "TidyCorePgm" True final_binds >> - 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 + -- Dump output + dumpIfSet (opt_D_dump_simpl || opt_D_verbose_core2core) + "Core transformations" + (pprCoreBindings pprDumpStyle final_binds) >> - ------------- - core_linter = if opt_DoCoreLinting - then lintCoreBindings ppr_style - else ( \ whodunnit spec_done binds -> binds ) + -- Report statistics + doIfSet opt_D_simplifier_stats + (hPutStr stderr ("\nSimplifier Stats:\n") >> + hPutStr stderr (showSimplCount simpl_stats) >> + hPutStr stderr "\n") >> + + -- Return results + return (final_binds, spec_data) + where + init_specdata = initSpecData local_tycons tycon_specs -------------- - do_core_pass info@(binds, us, inline_env, spec_data, simpl_stats) to_do - = let - (us1, us2) = splitUniqSupply us - in + do_core_pass info@(binds, us, spec_data, simpl_stats) to_do = + case (splitUniqSupply us) of + (us1,us2) -> case to_do of CoreDoSimplify simpl_sw_chkr -> _scc_ "CoreSimplify" @@ -146,7 +146,7 @@ core2core core_todos module_name ppr_style us local_tycons tycon_specs binds then " (foldr/build)" else "") >> 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 + -> end_pass us2 p spec_data simpl_stats2 ("Simplify (" ++ show it_cnt ++ ")" ++ if switchIsOn simpl_sw_chkr SimplDoFoldrBuild then " foldr/build" else "") @@ -155,49 +155,37 @@ core2core core_todos module_name ppr_style us local_tycons tycon_specs binds -> _scc_ "CoreDoFoldrBuildWorkerWrapper" begin_pass "FBWW" >> case (mkFoldrBuildWW us1 binds) of { binds2 -> - end_pass False us2 binds2 inline_env spec_data simpl_stats "FBWW" } + end_pass us2 binds2 spec_data simpl_stats "FBWW" } CoreDoFoldrBuildWWAnal -> _scc_ "CoreDoFoldrBuildWWAnal" begin_pass "AnalFBWW" >> case (analFBWW binds) of { binds2 -> - end_pass False us2 binds2 inline_env spec_data simpl_stats "AnalFBWW" } + end_pass us2 binds2 spec_data simpl_stats "AnalFBWW" } CoreLiberateCase -> _scc_ "LiberateCase" begin_pass "LiberateCase" >> - case (liberateCase lib_case_threshold binds) of { binds2 -> - end_pass False us2 binds2 inline_env spec_data simpl_stats "LiberateCase" } - - CoreDoCalcInlinings1 -- avoid inlinings w/ cost-centres - -> _scc_ "CoreInlinings1" - begin_pass "CalcInlinings" >> - case (calcInlinings False inline_env binds) of { inline_env2 -> - end_pass False us2 binds inline_env2 spec_data simpl_stats "CalcInlinings" } - - CoreDoCalcInlinings2 -- allow inlinings w/ cost-centres - -> _scc_ "CoreInlinings2" - begin_pass "CalcInlinings" >> - case (calcInlinings True inline_env binds) of { inline_env2 -> - end_pass False us2 binds inline_env2 spec_data simpl_stats "CalcInlinings" } + case (liberateCase opt_LiberateCaseThreshold binds) of { binds2 -> + end_pass us2 binds2 spec_data simpl_stats "LiberateCase" } CoreDoFloatInwards -> _scc_ "FloatInwards" begin_pass "FloatIn" >> case (floatInwards binds) of { binds2 -> - end_pass False us2 binds2 inline_env spec_data simpl_stats "FloatIn" } + end_pass us2 binds2 spec_data simpl_stats "FloatIn" } CoreDoFullLaziness -> _scc_ "CoreFloating" begin_pass "FloatOut" >> case (floatOutwards us1 binds) of { binds2 -> - end_pass False us2 binds2 inline_env spec_data simpl_stats "FloatOut" } + end_pass us2 binds2 spec_data simpl_stats "FloatOut" } CoreDoStaticArgs -> _scc_ "CoreStaticArgs" begin_pass "StaticArgs" >> case (doStaticArgs binds us1) of { binds2 -> - end_pass False us2 binds2 inline_env spec_data simpl_stats "StaticArgs" } + end_pass us2 binds2 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]) @@ -206,7 +194,7 @@ core2core core_todos module_name ppr_style us local_tycons tycon_specs binds -> _scc_ "CoreStranal" begin_pass "StrAnal" >> case (saWwTopBinds us1 binds) of { binds2 -> - end_pass False us2 binds2 inline_env spec_data simpl_stats "StrAnal" } + end_pass us2 binds2 spec_data simpl_stats "StrAnal" } CoreDoSpecialising -> _scc_ "Specialise" @@ -216,359 +204,633 @@ core2core core_todos module_name ppr_style us local_tycons tycon_specs binds 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 - hPutStr stderr (ppShow 1000 {-pprCols-} + doIfSet ((not spec_noerrs) || + (opt_ShowImportSpecs && not (isEmptyBag spec_warn))) + (printErrs (pprSpecErrs module_name spec_errs spec_warn spec_tyerrs)) - >> hPutStr stderr "\n" - else - return ()) >> + >> - (if not spec_noerrs then -- Stop here if specialisation errors occured - ghcExit 1 - else - return ()) >> + doIfSet (not spec_noerrs) -- Stop here if specialisation errors occured + (ghcExit 1) >> - end_pass False us2 p inline_env spec_data2 simpl_stats "Specialise" + end_pass us2 p spec_data2 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 False us2 binds2 inline_env spec_data simpl_stats "Deforestation" } -#endif - - CoreDoAutoCostCentres - -> _scc_ "AutoSCCs" - begin_pass "AutoSCCs" >> - case (addAutoCostCentres module_name binds) of { binds2 -> - end_pass False us2 binds2 inline_env spec_data simpl_stats "AutoSCCs" } - CoreDoPrintCore -- print result of last pass - -> end_pass True us2 binds inline_env spec_data simpl_stats "Print" - + -> dumpIfSet (not opt_D_verbose_core2core) "Print Core" + (pprCoreBindings pprDumpStyle binds) >> + return (binds, us1, spec_data, simpl_stats) ------------------------------------------------- - begin_pass + begin_pass what = if opt_D_show_passes - then \ what -> hPutStr stderr ("*** Core2Core: "++what++"\n") - else \ what -> return () + then hPutStr stderr ("*** Core2Core: "++what++"\n") + else return () - end_pass print us2 binds2 inline_env2 + end_pass us2 binds2 spec_data2@(SpecData spec_done _ _ _ _ _ _ _) simpl_stats2 what - = -- report verbosely, if required - (if (do_verbose_core2core && not print) || - (print && not do_verbose_core2core) - then - hPutStr stderr ("\n*** "++what++":\n") - >> - hPutStr stderr (ppShow 1000 - (ppAboves (map (pprCoreBinding ppr_style) binds2))) - >> - hPutStr stderr "\n" - else - return ()) >> - let - linted_binds = core_linter what spec_done binds2 - in + = -- Report verbosely, if required + dumpIfSet opt_D_verbose_core2core what + (pprCoreBindings pprDumpStyle binds2) >> + + lintCoreBindings what spec_done binds2 >> + return - (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 - ) + (binds2, -- processed binds, possibly run thru CoreLint + us2, -- UniqSupply for the next guy + spec_data2, -- possibly-updated specialisation info + 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 + foldl_mn f zz xs \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. -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. +%************************************************************************ +%* * +\subsection[SimplCore-indirections]{Eliminating indirections in Core code, and globalising} +%* * +%************************************************************************ + +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 + +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 + +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 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: + + case par# e of + True -> rhs + False -> parError# + ==> + case par# e of + _ -> rhs + +6. Eliminate polymorphic case expressions. We can't generate code for them yet. + +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.) + +8. Do let-to-case. See notes in Simplify.lhs for why we defer let-to-case + for multi-constructor types. + +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.] + + +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. + + -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. +\begin{code} +tidyCorePgm :: Module -> [CoreBinding] -> [CoreBinding] -We also need to check that everything in the RHS (values and types) -will be visible on the other side of an interface, too. +tidyCorePgm mod binds_in + = initTM mod indirection_env $ + tidyTopBindings (catMaybes reduced_binds) `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 +~~~~~~~~~~~~~~~~~~ \begin{code} -calcInlinings :: Bool -- True => inlinings with _scc_s are OK - -> IdEnv UnfoldingDetails - -> [CoreBinding] - -> IdEnv UnfoldingDetails +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) + where + (binders, 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') + +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) && + typeOkForCase (idType bndr) + = ASSERT( not (isPrimType (idType bndr)) ) + tidyCoreExpr (Case rhs (AlgAlts [] (BindDefault bndr body))) + +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 PprDebug 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') + 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} + +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') +tidyCoreArg (UsageArg u) = returnTM (UsageArg u) +\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} + + +%************************************************************************ +%* * +\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) + +litToRep (NoRepStr s) + = returnTM (stringTy, 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)))] -calcInlinings scc_s_OK inline_env_so_far top_binds + else -- No NULs in the string + App (Var unpackCStringId) (LitArg (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 + = Prim Int2IntegerOp [LitArg (mkMachInt i)] + + | otherwise -- Big, so start from a string + = Prim Addr2IntegerOp [LitArg (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]) + where + (ratio_data_con, integer_ty) + = case (maybeAppDataTyCon rational_ty) of + Just (tycon, [i_ty], [con]) + -> ASSERT(isIntegerTy i_ty && uniqueOf tycon == ratioTyConKey) + (con, i_ty) + + _ -> (panic "ratio_data_con", panic "integer_ty") + +litToRep other_lit = returnTM (literalType other_lit, Lit other_lit) +\end{code} + +\begin{code} +funnyParallelOp SeqOp = True +funnyParallelOp ParOp = True +funnyParallelOp ForkOp = True +funnyParallelOp _ = False +\end{code} + + +%************************************************************************ +%* * +\subsection{The monad} +%* * +%************************************************************************ + +\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 + +initTM :: Module -> UniqFM CoreBinder -> TopTidyM a -> a +initTM mod env m + = case m mod env initialTopTidyUnique 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') + +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' + +mapTM f [] = returnTM [] +mapTM f (x:xs) = f x `thenTM` \ r -> + mapTM f xs `thenTM` \ rs -> + returnTM (r:rs) +\end{code} + + +\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) = let - result = foldl calci inline_env_so_far top_binds + gus' = incrUnique gus + lit_local = mkSysLocal SLIT("lit") gus lit_ty noSrcLoc + 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 - - 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! + (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} -ANDY, on the hatred of the check above; why obliterate it? Consider - head xs = foldr (\ x _ -> x) (_|_) xs +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 + rn_id = setIdVisibility Nothing local_uniq id + id' = apply_to_Id (nmbr_ty env local_uniq') rn_id + env' = addToUFM env id (ValBinder id') + 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') + + +newTyVar tyvar thing_inside mod env (gus, local_uniq, floats) + = let + local_uniq' = incrUnique local_uniq + tyvar' = nameTyVar tyvar (uniqToOccName local_uniq) + 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 +~~~~~~~~~~~~~~~~~~ +\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 u_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} + -This then is exported via a pragma. However, -*if* you include the extra code above, you will -export the non-foldr/build version.