\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_D_dump_occur_anal, opt_D_dump_rules,
- opt_D_dump_simpl_iterations,
- opt_D_dump_simpl_stats,
- 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(..), HomePackageTable, Dependencies( dep_mods ),
+ hscEPS, hptRules )
import CSE ( cseProgram )
-import Rules ( RuleBase, ProtoCoreRule(..), pprProtoCoreRule, prepareLocalRuleBase,
- prepareOrphanRuleBase, unionRuleBase, localRule )
-import CoreUnfold
-import PprCore ( pprCoreBindings )
-import OccurAnal ( occurAnalyseBinds )
-import CoreUtils ( exprIsTrivial, etaReduceExpr, coreBindsSize )
+import Rules ( RuleBase, ruleBaseIds, emptyRuleBase,
+ extendRuleBaseList, pprRuleBase, ruleCheckProgram )
+import Module ( elemModuleEnv, lookupModuleEnv )
+import PprCore ( pprCoreBindings, pprCoreExpr, pprIdRules )
+import OccurAnal ( occurAnalyseBinds, occurAnalyseGlobalExpr )
+import CoreUtils ( coreBindsSize )
import Simplify ( simplTopBinds, simplExpr )
-import SimplUtils ( simplBinders )
+import SimplEnv ( SimplEnv, simplBinders, mkSimplEnv, setInScopeSet )
import SimplMonad
-import ErrUtils ( dumpIfSet )
+import ErrUtils ( dumpIfSet, dumpIfSet_dyn, showPass )
+import CoreLint ( endPass )
+import VarEnv ( mkInScopeSet )
import FloatIn ( floatInwards )
import FloatOut ( floatOutwards )
-import Id ( isDataConWrapId )
+import Id ( idIsFrom, idSpecialisation, setIdSpecialisation )
import VarSet
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 UniqSupply ( UniqSupply, mkSplitUniqSupply, splitUniqSupply )
import IO ( hPutStr, stderr )
import Outputable
-
-import List ( partition )
+import List ( partition )
+import Maybes ( orElse, fromJust )
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-core2core :: [CoreToDo] -- Spec of what core-to-core passes to do
- -> [CoreBind] -- Binds in
- -> [ProtoCoreRule] -- Rules in
- -> IO ([CoreBind], RuleBase) -- binds, local orphan rules out
+core2core :: HscEnv
+ -> ModGuts
+ -> IO ModGuts
-core2core core_todos binds rules
+core2core hsc_env guts
= do
- us <- mkSplitUniqSupply 's'
- let (cp_us, ru_us) = splitUniqSupply us
-
- let (local_rules, imported_rules) = partition localRule rules
+ let dflags = hsc_dflags hsc_env
+ core_todos
+ | Just todo <- dopt_CoreToDo dflags = todo
+ | otherwise = buildCoreToDo dflags
- better_local_rules <- simplRules ru_us local_rules binds
+ us <- mkSplitUniqSupply 's'
+ let (cp_us, ru_us) = splitUniqSupply us
- let (binds1, local_rule_base) = prepareLocalRuleBase binds better_local_rules
- imported_rule_base = prepareOrphanRuleBase imported_rules
+ -- COMPUTE THE RULE BASE TO USE
+ (imp_rule_base, guts') <- prepareRules hsc_env guts ru_us
- -- Do the main business
- (stats, processed_binds, processed_local_rules)
- <- doCorePasses zeroSimplCount cp_us binds1 local_rule_base
- imported_rule_base Nothing core_todos
+ -- DO THE BUSINESS
+ (stats, guts'') <- doCorePasses hsc_env cp_us
+ (zeroSimplCount dflags)
+ imp_rule_base guts' core_todos
- dumpIfSet opt_D_dump_simpl_stats
+ dumpIfSet_dyn dflags Opt_D_dump_simpl_stats
"Grand total simplifier statistics"
(pprSimplCount stats)
- -- Return results
- -- We only return local orphan rules, i.e., local rules not attached to an Id
- return (processed_binds, processed_local_rules)
+ return guts''
+
+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 :: SimplCount -- simplifier stats
+ ; 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
- -> [CoreBind] -- local binds in (with rules attached)
- -> RuleBase -- local orphan rules
- -> RuleBase -- imported and builtin rules
- -> Maybe RuleBase -- combined rulebase, or Nothing to ask for it to be rebuilt
+ -> SimplCount -- simplifier stats
+ -> RuleBase -- the main rule base
+ -> ModGuts -- local binds in (with rules attached)
-> [CoreToDo] -- which passes to do
- -> IO (SimplCount, [CoreBind], RuleBase) -- stats, binds, local orphan rules
+ -> IO (SimplCount, ModGuts)
-doCorePasses stats us binds lrb irb rb0 []
- = return (stats, binds, lrb)
+doCorePasses hsc_env us stats rb guts []
+ = return (stats, guts)
-doCorePasses stats us binds lrb irb rb0 (to_do : to_dos)
+doCorePasses hsc_env us stats rb guts (to_do : to_dos)
= do
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
- -- recompute rulebase if necessary
- let rb = maybe (irb `unionRuleBase` lrb) id rb0
-
- (stats1, binds1, mlrb1) <- doCorePass us1 binds lrb rb to_do
-
- -- request rulebase recomputation if pass returned a new local rulebase
- let (lrb1,rb1) = maybe (lrb, Just rb) (\ lrb1 -> (lrb1, Nothing)) mlrb1
-
- doCorePasses (stats `plusSimplCount` stats1) us2 binds1 lrb1 irb rb1 to_dos
-
-doCorePass us binds lrb rb (CoreDoSimplify sw_chkr) = _scc_ "Simplify" simplifyPgm rb sw_chkr us binds
-doCorePass us binds lrb rb CoreCSE = _scc_ "CommonSubExpr" noStats (cseProgram binds)
-doCorePass us binds lrb rb CoreLiberateCase = _scc_ "LiberateCase" noStats (liberateCase binds)
-doCorePass us binds lrb rb CoreDoFloatInwards = _scc_ "FloatInwards" noStats (floatInwards binds)
-doCorePass us binds lrb rb (CoreDoFloatOutwards f) = _scc_ "FloatOutwards" noStats (floatOutwards f us binds)
-doCorePass us binds lrb rb CoreDoStaticArgs = _scc_ "StaticArgs" noStats (doStaticArgs us binds)
-doCorePass us binds lrb rb CoreDoStrictness = _scc_ "Stranal" noStats (saBinds binds)
-doCorePass us binds lrb rb CoreDoWorkerWrapper = _scc_ "WorkWrap" noStats (wwTopBinds us binds)
-doCorePass us binds lrb rb CoreDoSpecialising = _scc_ "Specialise" noStats (specProgram us binds)
-doCorePass us binds lrb rb CoreDoCPResult = _scc_ "CPResult" noStats (cprAnalyse binds)
-doCorePass us binds lrb rb CoreDoPrintCore = _scc_ "PrintCore" noStats (printCore binds)
-doCorePass us binds lrb rb CoreDoUSPInf
- = _scc_ "CoreUsageSPInf"
- if opt_UsageSPOn then
- do
- (binds1, rules1) <- doUsageSPInf us binds lrb
- return (zeroSimplCount, binds1, rules1)
- else
- trace "WARNING: ignoring requested -fusagesp pass; requires -fusagesp-on" $
- return (zeroSimplCount, binds, Nothing)
-
-printCore binds = do dumpIfSet True "Print Core"
- (pprCoreBindings binds)
- return binds
-
--- most passes return no stats and don't change rules
-noStats thing = do { binds <- thing; return (zeroSimplCount, binds, Nothing) }
+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_deps = deps, 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)
+ home_pkg_rules = hptRules hsc_env (dep_mods deps)
+
+ (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 = extendRuleBaseList pkg_rule_base home_pkg_rules
+ 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 })
+ }
+
+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
+
+ update_bndrs (NonRec b r) = NonRec (update_bndr b) r
+ update_bndrs (Rec prs) = Rec [(update_bndr b, r) | (b,r) <- prs]
- sw_chkr any = SwBool False -- A bit bogus
+ update_bndr bndr = case lookupVarSet rule_ids bndr of
+ Nothing -> bndr
+ Just id -> bndr `setIdSpecialisation` idSpecialisation id
+\end{code}
- -- 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
+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.
-simplRule rule@(ProtoCoreRule is_local id (BuiltinRule _))
+\begin{code}
+simplRule env rule@(IdCoreRule id _ (BuiltinRule _ _))
= returnSmpl rule
-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'))
-
-simpl_arg e
--- I've seen rules in which a LHS like
+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}
%************************************************************************
\begin{code}
-simplifyPgm :: RuleBase
- -> (SimplifierSwitch -> SwitchResult)
+simplifyPgm :: SimplifierMode
+ -> [SimplifierSwitch]
+ -> HscEnv
-> UniqSupply
- -> [CoreBind] -- Input
- -> IO (SimplCount, [CoreBind], Maybe RuleBase) -- 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', Nothing)
+ return (counts_out, rule_base', guts')
}
where
- max_iterations = getSimplIntSwitch sw_chkr MaxSimplifierIterations
- black_list_fn = blackListed rule_lhs_fvs (intSwitchSet sw_chkr SimplInlinePhase)
+ 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)
+ }
- iteration us iteration_no counts binds
-- Try and force thunks off the binds; significantly reduces
-- space usage, especially with -O. JRS, 000620.
- | let sz = coreBindsSize binds in sz == sz
+ | 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
+ -- 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.
+
+ -- 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
-- t = initSmpl ...
-- counts' = snd t
-- in
- -- case t of {(_,counts') -> if counts'=0 then ...
+ -- case t of {(_,counts') -> if counts'=0 then ... }
-- So the conditional didn't force counts', because the
-- selection got duplicated. Sigh!
- case initSmpl sw_chkr us1 imported_rule_ids black_list_fn
- (simplTopBinds tagged_binds)
- of { (binds', counts') -> do {
- -- The imported_rule_ids are used by initSmpl to initialise
- -- the in-scope set. That way, the simplifier will change any
- -- occurrences of the imported id to the one in the imported_rule_ids
- -- set, which are decorated with their rules.
+ case initSmpl dflags us1 (_scc_ "SimplTopBinds" simplTopBinds simpl_env tagged_binds) of {
+ (binds', counts') -> do {
- let { all_counts = counts `plusSimplCount` counts' } ;
+ 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
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