X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FsimplCore%2FSimplCore.lhs;h=ec8ed27d99eb9fe06320b95ed9c0afef927d4015;hb=29ca2190efa2284e767949b0fab4e00a68db59bd;hp=ff7749e7057607f6a06b6c7e24b7b26477edf7e4;hpb=940841711bb0c30326a5173d8107c2792919641c;p=ghc-hetmet.git diff --git a/ghc/compiler/simplCore/SimplCore.lhs b/ghc/compiler/simplCore/SimplCore.lhs index ff7749e..ec8ed27 100644 --- a/ghc/compiler/simplCore/SimplCore.lhs +++ b/ghc/compiler/simplCore/SimplCore.lhs @@ -4,70 +4,51 @@ \section[SimplCore]{Driver for simplifying @Core@ programs} \begin{code} -module SimplCore ( core2core ) where +module SimplCore ( core2core, simplifyExpr ) where #include "HsVersions.h" -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_D_dump_occur_anal, - opt_UsageSPOn, +import CmdLineOpts ( CoreToDo(..), SimplifierSwitch(..), + SimplifierMode(..), DynFlags, DynFlag(..), dopt, + dopt_CoreToDo, buildCoreToDo ) -import CoreLint ( beginPass, endPass ) import CoreSyn +import TcIface ( loadImportedRules ) +import HscTypes ( HscEnv(..), ModGuts(..), ExternalPackageState(..), + ModDetails(..), HomeModInfo(..), hscEPS ) import CSE ( cseProgram ) -import Rules ( RuleBase, ProtoCoreRule(..), pprProtoCoreRule, prepareRuleBase, orphanRule ) -import CoreUnfold -import PprCore ( pprCoreBindings ) -import OccurAnal ( occurAnalyseBinds ) -import CoreUtils ( exprIsTrivial, etaReduceExpr ) +import Rules ( RuleBase, ruleBaseIds, emptyRuleBase, + extendRuleBaseList, pprRuleBase, ruleCheckProgram ) +import Module ( moduleEnvElts ) +import PprCore ( pprCoreBindings, pprCoreExpr, pprIdRules ) +import OccurAnal ( occurAnalyseBinds, occurAnalyseGlobalExpr ) +import CoreUtils ( coreBindsSize ) import Simplify ( simplTopBinds, simplExpr ) -import SimplUtils ( findDefault, simplBinders ) +import SimplEnv ( SimplEnv, simplBinders, mkSimplEnv, setInScopeSet ) import SimplMonad -import Literal ( Literal(..), literalType, mkMachInt ) -import ErrUtils ( dumpIfSet ) +import ErrUtils ( dumpIfSet, dumpIfSet_dyn, showPass ) +import CoreLint ( endPass ) +import VarEnv ( mkInScopeSet ) import FloatIn ( floatInwards ) import FloatOut ( floatOutwards ) -import Id ( Id, mkSysLocal, mkVanillaId, isBottomingId, isDataConWrapId, - idType, setIdType, idName, idInfo, setIdNoDiscard - ) -import VarEnv +import Id ( idIsFrom, idSpecialisation, setIdSpecialisation ) import VarSet -import Module ( Module ) -import Name ( mkLocalName, tidyOccName, tidyTopName, - NamedThing(..), OccName - ) -import TyCon ( TyCon, isDataTyCon ) -import PrelRules ( builtinRules ) -import Type ( Type, - isUnLiftedType, - tidyType, tidyTypes, tidyTopType, tidyTyVar, tidyTyVars, - Type - ) -import TysWiredIn ( smallIntegerDataCon, isIntegerTy ) import LiberateCase ( liberateCase ) import SAT ( doStaticArgs ) import Specialise ( specProgram) -import UsageSPInf ( doUsageSPInf ) -import StrictAnal ( saBinds ) +import SpecConstr ( specConstrProgram) +import DmdAnal ( dmdAnalPgm ) import WorkWrap ( wwTopBinds ) +#ifdef OLD_STRICTNESS +import StrictAnal ( saBinds ) import CprAnalyse ( cprAnalyse ) +#endif -import Unique ( Unique, Uniquable(..) ) -import UniqSupply ( UniqSupply, mkSplitUniqSupply, splitUniqSupply, uniqFromSupply ) -import Util ( mapAccumL ) -import SrcLoc ( noSrcLoc ) -import Bag -import Maybes +import UniqSupply ( UniqSupply, mkSplitUniqSupply, splitUniqSupply ) import IO ( hPutStr, stderr ) import Outputable - -import Ratio ( numerator, denominator ) +import List ( partition ) +import Maybes ( orElse ) \end{code} %************************************************************************ @@ -77,128 +58,327 @@ import Ratio ( numerator, denominator ) %************************************************************************ \begin{code} -core2core :: [CoreToDo] -- Spec of what core-to-core passes to do - -> [CoreBind] -- Binds in - -> [ProtoCoreRule] -- Rules - -> IO ([CoreBind], [ProtoCoreRule]) +core2core :: HscEnv + -> ModGuts + -> IO ModGuts -core2core core_todos binds rules +core2core hsc_env guts = do - us <- mkSplitUniqSupply 's' - let (cp_us, us1) = splitUniqSupply us - (ru_us, ps_us) = splitUniqSupply us1 + let dflags = hsc_dflags hsc_env + core_todos + | Just todo <- dopt_CoreToDo dflags = todo + | otherwise = buildCoreToDo dflags - better_rules <- simplRules ru_us rules binds + us <- mkSplitUniqSupply 's' + let (cp_us, ru_us) = splitUniqSupply us - let all_rules = builtinRules ++ better_rules - -- Here is where we add in the built-in rules + -- COMPUTE THE RULE BASE TO USE + (imp_rule_base, guts') <- prepareRules hsc_env guts ru_us - let (binds1, rule_base) = prepareRuleBase binds all_rules + -- DO THE BUSINESS + (stats, guts'') <- doCorePasses hsc_env cp_us + (zeroSimplCount dflags) + imp_rule_base guts' core_todos - -- Do the main business - (stats, processed_binds) <- doCorePasses zeroSimplCount cp_us binds1 - rule_base core_todos - - dumpIfSet opt_D_dump_simpl_stats + dumpIfSet_dyn dflags Opt_D_dump_simpl_stats "Grand total simplifier statistics" (pprSimplCount stats) - -- Return results - return (processed_binds, filter orphanRule better_rules) - + return guts'' + -doCorePasses stats us binds irs [] - = return (stats, binds) +simplifyExpr :: DynFlags -- includes spec of what core-to-core passes to do + -> CoreExpr + -> IO CoreExpr +-- simplifyExpr is called by the driver to simplify an +-- expression typed in at the interactive prompt +simplifyExpr dflags expr + = do { + ; showPass dflags "Simplify" -doCorePasses stats us binds irs (to_do : to_dos) + ; us <- mkSplitUniqSupply 's' + + ; let (expr', _counts) = initSmpl dflags us $ + simplExprGently gentleSimplEnv expr + + ; dumpIfSet_dyn dflags Opt_D_dump_simpl "Simplified expression" + (pprCoreExpr expr') + + ; return expr' + } + +gentleSimplEnv :: SimplEnv +gentleSimplEnv = mkSimplEnv SimplGently + (isAmongSimpl []) + emptyRuleBase + +doCorePasses :: HscEnv + -> UniqSupply -- uniques + -> SimplCount -- simplifier stats + -> RuleBase -- the main rule base + -> ModGuts -- local binds in (with rules attached) + -> [CoreToDo] -- which passes to do + -> IO (SimplCount, ModGuts) + +doCorePasses hsc_env us stats rb guts [] + = return (stats, guts) + +doCorePasses hsc_env us stats rb guts (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 (CoreDoFloatOutwards f) = _scc_ "FloatOutwards" noStats (floatOutwards f 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) } + let (us1, us2) = splitUniqSupply us + (stats1, rb1, guts1) <- doCorePass to_do hsc_env us1 rb guts + doCorePasses hsc_env us2 (stats `plusSimplCount` stats1) rb1 guts1 to_dos + +doCorePass (CoreDoSimplify mode sws) = _scc_ "Simplify" simplifyPgm mode sws +doCorePass CoreCSE = _scc_ "CommonSubExpr" trBinds cseProgram +doCorePass CoreLiberateCase = _scc_ "LiberateCase" trBinds liberateCase +doCorePass CoreDoFloatInwards = _scc_ "FloatInwards" trBinds floatInwards +doCorePass (CoreDoFloatOutwards f) = _scc_ "FloatOutwards" trBindsU (floatOutwards f) +doCorePass CoreDoStaticArgs = _scc_ "StaticArgs" trBinds doStaticArgs +doCorePass CoreDoStrictness = _scc_ "Stranal" trBinds dmdAnalPgm +doCorePass CoreDoWorkerWrapper = _scc_ "WorkWrap" trBindsU wwTopBinds +doCorePass CoreDoSpecialising = _scc_ "Specialise" trBindsU specProgram +doCorePass CoreDoSpecConstr = _scc_ "SpecConstr" trBindsU specConstrProgram +doCorePass CoreDoGlomBinds = trBinds glomBinds +doCorePass CoreDoPrintCore = observe printCore +doCorePass (CoreDoRuleCheck phase pat) = observe (ruleCheck phase pat) +doCorePass CoreDoNothing = observe (\ _ _ -> return ()) +#ifdef OLD_STRICTNESS +doCorePass CoreDoOldStrictness = _scc_ "OldStrictness" trBinds doOldStrictness +#endif + +#ifdef OLD_STRICTNESS +doOldStrictness dfs binds + = do binds1 <- saBinds dfs binds + binds2 <- cprAnalyse dfs binds1 + return binds2 +#endif + +printCore _ binds = dumpIfSet True "Print Core" (pprCoreBindings binds) + +ruleCheck phase pat dflags binds = do showPass dflags "RuleCheck" + printDump (ruleCheckProgram phase pat binds) + +-- Most passes return no stats and don't change rules +trBinds :: (DynFlags -> [CoreBind] -> IO [CoreBind]) + -> HscEnv -> UniqSupply -> RuleBase -> ModGuts + -> IO (SimplCount, RuleBase, ModGuts) +trBinds do_pass hsc_env us rb guts + = do { binds' <- do_pass dflags (mg_binds guts) + ; return (zeroSimplCount dflags, rb, guts { mg_binds = binds' }) } + where + dflags = hsc_dflags hsc_env + +trBindsU :: (DynFlags -> UniqSupply -> [CoreBind] -> IO [CoreBind]) + -> HscEnv -> UniqSupply -> RuleBase -> ModGuts + -> IO (SimplCount, RuleBase, ModGuts) +trBindsU do_pass hsc_env us rb guts + = do { binds' <- do_pass dflags us (mg_binds guts) + ; return (zeroSimplCount dflags, rb, guts { mg_binds = binds' }) } + where + dflags = hsc_dflags hsc_env + +-- Observer passes just peek; don't modify the bindings at all +observe :: (DynFlags -> [CoreBind] -> IO a) + -> HscEnv -> UniqSupply -> RuleBase -> ModGuts + -> IO (SimplCount, RuleBase, ModGuts) +observe do_pass hsc_env us rb guts + = do { binds <- do_pass dflags (mg_binds guts) + ; return (zeroSimplCount dflags, rb, guts) } + where + dflags = hsc_dflags hsc_env \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. +-- prepareLocalRuleBase takes the CoreBinds and rules defined in this module. +-- It attaches those rules that are for local Ids to their binders, and +-- returns the remainder attached to Ids in an IdSet. \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 +prepareRules :: HscEnv + -> ModGuts + -> UniqSupply + -> IO (RuleBase, -- Rule base for imported things, incl + -- (a) rules defined in this module (orphans) + -- (b) rules from other packages + -- (c) rules from other modules in home package + ModGuts) -- Modified fields are + -- (a) Bindings have rules attached, + -- (b) Rules are now just orphan rules + +prepareRules hsc_env@(HscEnv { hsc_dflags = dflags, hsc_HPT = hpt }) + guts@(ModGuts { mg_binds = binds, mg_rules = local_rules }) + us + = do { eps <- hscEPS hsc_env + + ; let -- Simplify the local rules; boringly, we need to make an in-scope set + -- from the local binders, to avoid warnings from Simplify.simplVar + local_ids = mkInScopeSet (mkVarSet (bindersOfBinds binds)) + env = setInScopeSet gentleSimplEnv local_ids + (better_rules,_) = initSmpl dflags us (mapSmpl (simplRule env) local_rules) + + (orphan_rules, rules_for_locals) = partition isOrphanRule better_rules + -- Get the rules for locally-defined Ids out of the RuleBase + -- If we miss any rules for Ids defined here, then we end up + -- giving the local decl a new Unique (because the in-scope-set is (hackily) the + -- same as the non-local-rule-id set, so the Id looks as if it's in scope + -- and hence should be cloned), and now the binding for the class method + -- doesn't have the same Unique as the one in the Class and the tc-env + -- Example: class Foo a where + -- op :: a -> a + -- {-# RULES "op" op x = x #-} + + -- NB: we assume that the imported rules dont include + -- rules for Ids in this module; if there is, the above bad things may happen + + pkg_rule_base = eps_rule_base eps + hpt_rule_base = foldl add_rules pkg_rule_base (moduleEnvElts hpt) + imp_rule_base = extendRuleBaseList hpt_rule_base orphan_rules + + -- Update the binders in the local bindings with the lcoal rules + -- Update the binders of top-level bindings by + -- attaching the rules for each locally-defined Id to that Id. + -- + -- Reason + -- - It makes the rules easier to look up + -- - It means that transformation rules and specialisations for + -- locally defined Ids are handled uniformly + -- - It keeps alive things that are referred to only from a rule + -- (the occurrence analyser knows about rules attached to Ids) + -- - It makes sure that, when we apply a rule, the free vars + -- of the RHS are more likely to be in scope + -- - The imported rules are carried in the in-scope set + -- which is extended on each iteration by the new wave of + -- local binders; any rules which aren't on the binding will + -- thereby get dropped + local_rule_base = extendRuleBaseList emptyRuleBase rules_for_locals + binds_w_rules = updateBinders local_rule_base binds + + ; dumpIfSet_dyn dflags Opt_D_dump_rules "Transformation rules" + (vcat [text "Local rules", pprIdRules better_rules, + text "", + text "Imported rules", pprRuleBase imp_rule_base]) + +#ifdef DEBUG + ; let bad_rules = filter (idIsFrom (mg_module guts)) + (varSetElems (ruleBaseIds imp_rule_base)) + ; WARN( not (null bad_rules), ppr bad_rules ) return () +#endif + ; return (imp_rule_base, guts { mg_binds = binds_w_rules, mg_rules = orphan_rules }) + } + where + add_rules rule_base mod_info = extendRuleBaseList rule_base (md_rules (hm_details mod_info)) + +updateBinders :: RuleBase -> [CoreBind] -> [CoreBind] +updateBinders rule_base binds + = map update_bndrs binds where - black_list_all v = not (isDataConWrapId v) - -- This stops all inlining except the - -- wrappers for data constructors + rule_ids = ruleBaseIds rule_base - sw_chkr any = SwBool False -- A bit bogus + update_bndrs (NonRec b r) = NonRec (update_bndr b) r + update_bndrs (Rec prs) = Rec [(update_bndr b, r) | (b,r) <- prs] - -- 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 + update_bndr bndr = case lookupVarSet rule_ids bndr of + Nothing -> bndr + Just id -> bndr `setIdSpecialisation` idSpecialisation id +\end{code} -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 simpl_arg args `thenSmpl` \ args' -> - simplExpr rhs `thenSmpl` \ rhs' -> - returnSmpl (ProtoCoreRule is_local id (Rule name bndrs' args' rhs')) +We must do some gentle simplification 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. -simpl_arg e --- I've seen rules in which a LHS like +\begin{code} +simplRule env rule@(IdCoreRule id _ (BuiltinRule _ _)) + = returnSmpl rule +simplRule env (IdCoreRule id is_orph (Rule act name bndrs args rhs)) + = simplBinders env bndrs `thenSmpl` \ (env, bndrs') -> + mapSmpl (simplExprGently env) args `thenSmpl` \ args' -> + simplExprGently env rhs `thenSmpl` \ rhs' -> + returnSmpl (IdCoreRule id is_orph (Rule act name bndrs' args' rhs')) + +-- It's important that simplExprGently does eta reduction. +-- For example, in a rule like: -- augment g (build h) --- turns into +-- we do not want to get -- augment (\a. g a) (build h) --- So it's a help to eta-reduce the args as we simplify them. --- Otherwise we don't match when given an argument like +-- otherwise we don't match when given an argument like -- (\a. h a a) - = simplExpr e `thenSmpl` \ e' -> - returnSmpl (etaReduceExpr e') +-- +-- The simplifier does indeed do eta reduction (it's in +-- Simplify.completeLam) but only if -O is on. +\end{code} + +\begin{code} +simplExprGently :: SimplEnv -> CoreExpr -> SimplM CoreExpr +-- Simplifies an expression +-- does occurrence analysis, then simplification +-- and repeats (twice currently) because one pass +-- alone leaves tons of crud. +-- Used (a) for user expressions typed in at the interactive prompt +-- (b) the LHS and RHS of a RULE +-- +-- The name 'Gently' suggests that the SimplifierMode is SimplGently, +-- and in fact that is so.... but the 'Gently' in simplExprGently doesn't +-- enforce that; it just simplifies the expression twice + +simplExprGently env expr + = simplExpr env (occurAnalyseGlobalExpr expr) `thenSmpl` \ expr1 -> + simplExpr env (occurAnalyseGlobalExpr expr1) +\end{code} + + +%************************************************************************ +%* * +\subsection{Glomming} +%* * +%************************************************************************ + +\begin{code} +glomBinds :: DynFlags -> [CoreBind] -> IO [CoreBind] +-- 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. +-- This pass lets us control where it happens. +-- +-- NOTICE that this cannot happen for rules whose head is a locally-defined +-- function. It only happens for rules whose head is an imported function +-- (p in the example above). So, for example, the rule had been +-- RULE: f (p x) = h x +-- then the rule for f would be attached to f itself (in its IdInfo) +-- by prepareLocalRuleBase and h would be regarded by the occurrency +-- analyser as free in f. + +glomBinds dflags binds + = do { showPass dflags "GlomBinds" ; + let { recd_binds = [Rec (flattenBinds binds)] } ; + return recd_binds } + -- Not much point in printing the result... + -- just consumes output bandwidth \end{code} + %************************************************************************ %* * \subsection{The driver for the simplifier} @@ -206,113 +386,121 @@ simpl_arg e %************************************************************************ \begin{code} -simplifyPgm :: RuleBase - -> (SimplifierSwitch -> SwitchResult) +simplifyPgm :: SimplifierMode + -> [SimplifierSwitch] + -> HscEnv -> UniqSupply - -> [CoreBind] -- Input - -> IO (SimplCount, [CoreBind]) -- New bindings + -> RuleBase + -> ModGuts + -> IO (SimplCount, RuleBase, ModGuts) -- New bindings -simplifyPgm (imported_rule_ids, rule_lhs_fvs) - sw_chkr us binds +simplifyPgm mode switches hsc_env us rule_base guts = 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) + showPass dflags "Simplify"; + + (termination_msg, it_count, counts_out, rule_base', guts') + <- do_iteration us rule_base 1 (zeroSimplCount dflags) guts; + + dumpIfSet (dopt Opt_D_verbose_core2core dflags + && dopt Opt_D_dump_simpl_stats dflags) "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' ; + endPass dflags "Simplify" Opt_D_verbose_core2core (mg_binds guts'); - return (counts_out, binds') + return (counts_out, rule_base', guts') } 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 + dflags = hsc_dflags hsc_env + phase_info = case mode of + SimplGently -> "gentle" + SimplPhase n -> show n + + sw_chkr = isAmongSimpl switches + max_iterations = intSwitchSet sw_chkr MaxSimplifierIterations `orElse` 2 + + do_iteration us rule_base iteration_no counts guts + -- iteration_no is the number of the iteration we are + -- about to begin, with '1' for the first + | iteration_no > max_iterations -- Stop if we've run out of iterations + = do { +#ifdef DEBUG + if max_iterations > 2 then + hPutStr stderr ("NOTE: Simplifier still going after " ++ + show max_iterations ++ + " iterations; bailing out.\n") + else + return (); +#endif + -- Subtract 1 from iteration_no to get the + -- number of iterations we actually completed + return ("Simplifier baled out", iteration_no - 1, counts, rule_base, guts) + } + + -- Try and force thunks off the binds; significantly reduces + -- space usage, especially with -O. JRS, 000620. + | let sz = coreBindsSize (mg_binds guts) in sz == sz = do { -- Occurrence analysis - let { tagged_binds = _scc_ "OccAnal" occurAnalyseBinds binds } ; + let { tagged_binds = _scc_ "OccAnal" occurAnalyseBinds (mg_binds guts) } ; - dumpIfSet opt_D_dump_occur_anal "Occurrence analysis" + dumpIfSet_dyn dflags 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 + -- Get any new rules, and extend the rule base + -- (on the side this extends the package rule base in the + -- ExternalPackageTable, ready for the next complation + -- in --make mode) + -- We need to do this regularly, because simplification can + -- poke on IdInfo thunks, which in turn brings in new rules + -- behind the scenes. Otherwise there's a danger we'll simply + -- miss the rules for Ids hidden inside imported inlinings + new_rules <- loadImportedRules hsc_env guts ; + let { rule_base' = extendRuleBaseList rule_base new_rules + ; simpl_env = mkSimplEnv mode sw_chkr rule_base' } ; + -- The new rule base Ids are used 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' - } ; + + -- Simplify the program + -- We do this with a *case* not a *let* because lazy pattern + -- matching bit us with bad space leak! + -- With a let, we ended up with + -- let + -- t = initSmpl ... + -- counts' = snd t + -- in + -- case t of {(_,counts') -> if counts'=0 then ... } + -- So the conditional didn't force counts', because the + -- selection got duplicated. Sigh! + case initSmpl dflags us1 (simplTopBinds simpl_env tagged_binds) of { + (binds', counts') -> do { + + let { guts' = guts { mg_binds = binds' } + ; all_counts = counts `plusSimplCount` counts' + ; herald = "Simplifier phase " ++ phase_info ++ + ", iteration " ++ show iteration_no ++ + " out of " ++ show max_iterations + } ; -- Stop if nothing happened; don't dump output if isZeroSimplCount counts' then - return ("Simplifier reached fixed point", iteration_no, all_counts, binds') + return ("Simplifier reached fixed point", iteration_no, + all_counts, rule_base', guts') 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 (); + dumpIfSet_dyn dflags Opt_D_dump_simpl_iterations herald + (pprSimplCount counts') ; - return ("Simplifier baled out", iteration_no, all_counts, binds') - } + endPass dflags herald Opt_D_dump_simpl_iterations binds' ; - -- Else loop - else iteration us2 (iteration_no + 1) all_counts binds' - } } + -- Loop + do_iteration us2 rule_base' (iteration_no + 1) all_counts guts' + } } } } where (us1, us2) = splitUniqSupply us \end{code}