X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FsimplCore%2FSimplCore.lhs;h=6c07ba998ff4eaed44fcb30fdac691cdaa4fde54;hb=12e6a9a58473f8b24e831c2171bf62d256da8a85;hp=15257e7219a847e2ce3d2fbdd8ca9e553ca6a5cc;hpb=d893f3809b61eca1b7a45f3eb63d39b25f757c40;p=ghc-hetmet.git diff --git a/ghc/compiler/simplCore/SimplCore.lhs b/ghc/compiler/simplCore/SimplCore.lhs index 15257e7..6c07ba9 100644 --- a/ghc/compiler/simplCore/SimplCore.lhs +++ b/ghc/compiler/simplCore/SimplCore.lhs @@ -4,38 +4,40 @@ \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(..), intSwitchSet, - opt_UsageSPOn, DynFlags, DynFlag(..), dopt, dopt_CoreToDo ) -import CoreLint ( beginPass, endPass ) +import CoreLint ( showPass, endPass ) import CoreSyn -import CoreFVs ( ruleSomeFreeVars ) -import HscTypes ( PackageRuleBase, HomeSymbolTable, ModDetails(..) ) +import CoreFVs ( ruleRhsFreeVars ) +import HscTypes ( PersistentCompilerState(..), + PackageRuleBase, HomeSymbolTable, IsExported, ModDetails(..) + ) import CSE ( cseProgram ) import Rules ( RuleBase, emptyRuleBase, ruleBaseFVs, ruleBaseIds, extendRuleBaseList, addRuleBaseFVs ) import Module ( moduleEnvElts ) import CoreUnfold -import PprCore ( pprCoreBindings, pprIdCoreRule ) -import OccurAnal ( occurAnalyseBinds ) -import CoreUtils ( etaReduceExpr, coreBindsSize ) +import PprCore ( pprCoreBindings, pprIdCoreRule, pprCoreExpr ) +import OccurAnal ( occurAnalyseBinds, occurAnalyseGlobalExpr ) +import CoreUtils ( coreBindsSize ) import Simplify ( simplTopBinds, simplExpr ) import SimplUtils ( simplBinders ) import SimplMonad import ErrUtils ( dumpIfSet, dumpIfSet_dyn ) import FloatIn ( floatInwards ) import FloatOut ( floatOutwards ) -import Id ( Id, isDataConWrapId, setIdNoDiscard ) +import Id ( idName, isDataConWrapId, setIdNoDiscard, isLocalId ) import VarSet import LiberateCase ( liberateCase ) import SAT ( doStaticArgs ) import Specialise ( specProgram) +import SpecConstr ( specConstrProgram) import UsageSPInf ( doUsageSPInf ) import StrictAnal ( saBinds ) import WorkWrap ( wwTopBinds ) @@ -45,6 +47,7 @@ import UniqSupply ( UniqSupply, mkSplitUniqSupply, splitUniqSupply ) import IO ( hPutStr, stderr ) import Outputable +import Maybes ( orElse ) import List ( partition ) \end{code} @@ -56,22 +59,27 @@ import List ( partition ) \begin{code} core2core :: DynFlags -- includes spec of what core-to-core passes to do - -> PackageRuleBase -- Rule-base accumulated from imported packages + -> PersistentCompilerState -> HomeSymbolTable + -> IsExported -> [CoreBind] -- Binds in - -> [IdCoreRule] -- Rules in + -> [IdCoreRule] -- Rules defined in this module -> IO ([CoreBind], [IdCoreRule]) -- binds, local orphan rules out -core2core dflags pkg_rule_base hst binds rules +core2core dflags pcs hst is_exported binds rules = do - let core_todos = dopt_CoreToDo dflags + let core_todos = dopt_CoreToDo dflags + let pkg_rule_base = pcs_rules pcs -- Rule-base accumulated from imported packages + us <- mkSplitUniqSupply 's' let (cp_us, ru_us) = splitUniqSupply us -- COMPUTE THE RULE BASE TO USE - (rule_base, binds1, orphan_rules) + (rule_base, local_rule_ids, orphan_rules, rule_rhs_fvs) <- prepareRules dflags pkg_rule_base hst ru_us binds rules + -- PREPARE THE BINDINGS + let binds1 = updateBinders local_rule_ids rule_rhs_fvs is_exported binds -- DO THE BUSINESS (stats, processed_binds) @@ -87,6 +95,32 @@ core2core dflags pkg_rule_base hst binds rules return (processed_binds, orphan_rules) +simplifyExpr :: DynFlags -- includes spec of what core-to-core passes to do + -> PersistentCompilerState + -> HomeSymbolTable + -> CoreExpr + -> IO CoreExpr +-- simplifyExpr is called by the driver to simplify an +-- expression typed in at the interactive prompt +simplifyExpr dflags pcs hst expr + = do { + ; showPass dflags "Simplify" + + ; us <- mkSplitUniqSupply 's' + + ; let (expr', _counts) = initSmpl dflags sw_chkr us emptyVarSet black_list_nothing + (simplExprGently expr) + + ; dumpIfSet_dyn dflags Opt_D_dump_simpl "Simplified expression" + (pprCoreExpr expr') + + ; return expr' + } + where + sw_chkr any = SwBool False -- A bit bogus + black_list_nothing v = False -- Black list nothing + + doCorePasses :: DynFlags -> RuleBase -- the main rule base -> SimplCount -- simplifier stats @@ -124,6 +158,8 @@ doCorePass dfs rb us binds CoreDoWorkerWrapper = _scc_ "WorkWrap" noStats dfs (wwTopBinds dfs us binds) doCorePass dfs rb us binds CoreDoSpecialising = _scc_ "Specialise" noStats dfs (specProgram dfs us binds) +doCorePass dfs rb us binds CoreDoSpecConstr + = _scc_ "SpecConstr" noStats dfs (specConstrProgram dfs us binds) doCorePass dfs rb us binds CoreDoCPResult = _scc_ "CPResult" noStats dfs (cprAnalyse dfs binds) doCorePass dfs rb us binds CoreDoPrintCore @@ -132,6 +168,8 @@ doCorePass dfs rb us binds CoreDoUSPInf = _scc_ "CoreUsageSPInf" noStats dfs (doUsageSPInf dfs us binds) doCorePass dfs rb us binds CoreDoGlomBinds = noStats dfs (glomBinds dfs binds) +doCorePass dfs rb us binds CoreDoNothing + = noStats dfs (return binds) printCore binds = do dumpIfSet True "Print Core" (pprCoreBindings binds) @@ -160,10 +198,12 @@ noStats dfs thing = do { binds <- thing; return (zeroSimplCount dfs, binds) } \begin{code} prepareRules :: DynFlags -> PackageRuleBase -> HomeSymbolTable -> UniqSupply - -> [CoreBind] -> [IdCoreRule] -- Local bindings and rules - -> IO (RuleBase, -- Full rule base - [CoreBind], -- Bindings augmented with rules - [IdCoreRule]) -- Orphan rules + -> [CoreBind] + -> [IdCoreRule] -- Local rules + -> IO (RuleBase, -- Full rule base + IdSet, -- Local rule Ids + [IdCoreRule], -- Orphan rules + IdSet) -- RHS free vars of all rules prepareRules dflags pkg_rule_base hst us binds rules = do { let (better_rules,_) = initSmpl dflags sw_chkr us local_ids black_list_all @@ -172,14 +212,15 @@ prepareRules dflags pkg_rule_base hst us binds rules ; dumpIfSet_dyn dflags Opt_D_dump_rules "Transformation rules" (vcat (map pprIdCoreRule better_rules)) - ; let (local_id_rules, orphan_rules) = partition ((`elemVarSet` local_ids) . fst) better_rules - (binds1, local_rule_fvs) = addRulesToBinds binds local_id_rules - imp_rule_base = foldl add_rules pkg_rule_base (moduleEnvElts hst) - rule_base = extendRuleBaseList imp_rule_base orphan_rules - final_rule_base = addRuleBaseFVs rule_base local_rule_fvs + ; let (local_rules, orphan_rules) = partition (isLocalId . fst) better_rules + rule_rhs_fvs = unionVarSets (map (ruleRhsFreeVars . snd) better_rules) + local_rule_base = extendRuleBaseList emptyRuleBase local_rules + local_rule_ids = ruleBaseIds local_rule_base -- Local Ids with rules attached + imp_rule_base = foldl add_rules pkg_rule_base (moduleEnvElts hst) + rule_base = extendRuleBaseList imp_rule_base orphan_rules + final_rule_base = addRuleBaseFVs rule_base (ruleBaseFVs local_rule_base) -- The last step black-lists the free vars of local rules too - - ; return (final_rule_base, binds1, orphan_rules) + ; return (final_rule_base, local_rule_ids, orphan_rules, rule_rhs_fvs) } where sw_chkr any = SwBool False -- A bit bogus @@ -194,42 +235,46 @@ prepareRules dflags pkg_rule_base hst us binds rules -- simpVar fails if it isn't right, and it might conceiveably matter local_ids = foldr (unionVarSet . mkVarSet . bindersOf) emptyVarSet binds -addRulesToBinds :: [CoreBind] -> [(Id,CoreRule)] -> ([CoreBind], IdSet) + +updateBinders :: IdSet -- Locally defined ids with their Rules attached + -> IdSet -- Ids free in the RHS of local rules + -> IsExported + -> [CoreBind] -> [CoreBind] -- A horrible function - -- Attach the rules for each locally-defined Id to that Id. - -- - This 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 - -- - -- Both the LHS and RHS Ids are marked 'no-discard'. - -- This means that the binding won't be discarded EVEN if the binding - -- ends up being trivial (v = w) -- the simplifier would usually just - -- substitute w for v throughout, but we don't apply the substitution to - -- the rules (maybe we should?), so this substitution would make the rule - -- bogus. - -addRulesToBinds binds local_rules - = (map zap_bind binds, rule_lhs_fvs) +-- Update the binders of top-level bindings as follows +-- a) Attach the rules for each locally-defined Id to that Id. +-- b) Set the no-discard flag if either the Id is exported, +-- or it's mentoined in the RHS of a rule +-- +-- Reason for (a) +-- - 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 +-- +-- Reason for (b) +-- It means that the binding won't be discarded EVEN if the binding +-- ends up being trivial (v = w) -- the simplifier would usually just +-- substitute w for v throughout, but we don't apply the substitution to +-- the rules (maybe we should?), so this substitution would make the rule +-- bogus. + +updateBinders rule_ids rule_rhs_fvs is_exported binds + = map update_bndrs binds where - -- rule_fvs is the set of all variables mentioned in this module's rules - rule_fvs = unionVarSets [ ruleSomeFreeVars isId rule | (_,rule) <- local_rules ] - - rule_base = extendRuleBaseList emptyRuleBase local_rules - rule_lhs_fvs = ruleBaseFVs rule_base - rule_ids = ruleBaseIds rule_base - - zap_bind (NonRec b r) = NonRec (zap_bndr b) r - zap_bind (Rec prs) = Rec [(zap_bndr b, r) | (b,r) <- prs] - - zap_bndr bndr = case lookupVarSet rule_ids bndr of - Just bndr' -> setIdNoDiscard bndr' - Nothing | bndr `elemVarSet` rule_fvs -> setIdNoDiscard bndr - | otherwise -> bndr + update_bndrs (NonRec b r) = NonRec (update_bndr b) r + update_bndrs (Rec prs) = Rec [(update_bndr b, r) | (b,r) <- prs] + + update_bndr bndr + | is_exported (idName bndr) + || bndr `elemVarSet` rule_rhs_fvs = setIdNoDiscard bndr' + | otherwise = bndr' + where + bndr' = lookupVarSet rule_ids bndr `orElse` bndr \end{code} @@ -244,20 +289,33 @@ simplRule rule@(id, BuiltinRule _) = returnSmpl rule simplRule rule@(id, Rule name bndrs args rhs) = simplBinders bndrs $ \ bndrs' -> - mapSmpl simpl_arg args `thenSmpl` \ args' -> - simplExpr rhs `thenSmpl` \ rhs' -> + mapSmpl simplExprGently args `thenSmpl` \ args' -> + simplExprGently rhs `thenSmpl` \ rhs' -> returnSmpl (id, Rule name bndrs' args' rhs') -simpl_arg e --- I've seen rules in which a LHS like +-- 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 :: 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 +simplExprGently expr + = simplExpr (occurAnalyseGlobalExpr expr) `thenSmpl` \ expr1 -> + simplExpr (occurAnalyseGlobalExpr expr1) \end{code} @@ -295,7 +353,7 @@ glomBinds :: DynFlags -> [CoreBind] -> IO [CoreBind] -- analyser as free in f. glomBinds dflags binds - = do { beginPass dflags "GlomBinds" ; + = do { showPass dflags "GlomBinds" ; let { recd_binds = [Rec (flattenBinds binds)] } ; return recd_binds } -- Not much point in printing the result... @@ -320,7 +378,7 @@ simplifyPgm :: DynFlags simplifyPgm dflags rule_base sw_chkr us binds = do { - beginPass dflags "Simplify"; + showPass dflags "Simplify"; (termination_msg, it_count, counts_out, binds') <- iteration us 1 (zeroSimplCount dflags) binds; @@ -332,10 +390,7 @@ simplifyPgm dflags rule_base text "", pprSimplCount counts_out]); - endPass dflags "Simplify" - (dopt Opt_D_verbose_core2core dflags - && not (dopt Opt_D_dump_simpl_iterations dflags)) - binds' ; + endPass dflags "Simplify" Opt_D_verbose_core2core binds'; return (counts_out, binds') } @@ -388,13 +443,10 @@ simplifyPgm dflags rule_base ++ " out of " ++ show max_iterations) (pprSimplCount counts') ; - if dopt Opt_D_dump_simpl_iterations dflags then - endPass dflags - ("Simplifier iteration " ++ show iteration_no ++ " result") - (dopt Opt_D_verbose_core2core dflags) - binds' - else - return [] ; + endPass dflags + ("Simplifier iteration " ++ show iteration_no ++ " result") + Opt_D_dump_simpl_iterations + binds' ; -- Stop if we've run out of iterations if iteration_no == max_iterations then