%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1995
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[SimplCore]{Driver for simplifying @Core@ programs}
\begin{code}
-#include "HsVersions.h"
-
-module SimplCore (
- core2core,
-
- IdEnv(..),
- UnfoldingDetails,
- SpecialiseData(..),
- UniqFM, Unique, Bag
- ) where
-
-IMPORT_Trace
-import Outputable
-import Pretty
+module SimplCore ( core2core ) where
-import PlainCore
+#include "HsVersions.h"
-import AbsUniType ( getTyConDataCons, alpha_ty, alpha_tyvar, beta_ty, beta_tyvar )
---SAVE:import ArityAnal ( arityAnalProgram )
-import Bag
-import BinderInfo ( BinderInfo) -- instances only
-import CgCompInfo ( uNFOLDING_CREATION_THRESHOLD,
- uNFOLDING_USE_THRESHOLD,
- uNFOLDING_OVERRIDE_THRESHOLD,
- uNFOLDING_CON_DISCOUNT_WEIGHT
+import CmdLineOpts ( CoreToDo(..), SimplifierSwitch(..),
+ SwitchResult, switchIsOn,
+ opt_D_dump_occur_anal,
+ opt_D_dump_simpl_iterations,
+ opt_D_simplifier_stats,
+ opt_D_dump_simpl,
+ opt_D_verbose_core2core,
+ opt_D_dump_occur_anal
)
-import CmdLineOpts
-import CoreLint ( lintCoreBindings )
+import CoreLint ( beginPass, endPass )
+import CoreSyn
+import PprCore ( pprCoreBindings )
+import OccurAnal ( occurAnalyseBinds )
+import CoreUtils ( exprIsTrivial, coreExprType )
+import Simplify ( simplBind )
+import SimplUtils ( etaCoreExpr, findDefault )
+import SimplMonad
+import CoreUnfold
+import Const ( Con(..), Literal(..), literalType, mkMachInt )
+import ErrUtils ( dumpIfSet )
import FloatIn ( floatInwards )
import FloatOut ( floatOutwards )
-import Id ( getIdUnfolding,
- getIdUniType, toplevelishId,
- idWantsToBeINLINEd,
- unfoldingUnfriendlyId, isWrapperId,
- mkTemplateLocals
- IF_ATTACK_PRAGMAS(COMMA getIdStrictness)
+import Id ( Id, mkSysLocal, mkUserId, isBottomingId,
+ idType, setIdType, idName, idInfo, idDetails
+ )
+import IdInfo ( InlinePragInfo(..), specInfo, setSpecInfo,
+ inlinePragInfo, setInlinePragInfo,
+ setUnfoldingInfo
)
-import IdEnv
-import IdInfo
+import VarEnv
+import VarSet
+import Name ( mkLocalName, tidyOccName, tidyTopName, initTidyOccEnv, isExported,
+ Module, NamedThing(..), OccName
+ )
+import TyCon ( TyCon, isDataTyCon )
+import PrimOp ( PrimOp(..) )
+import PrelInfo ( unpackCStringId, unpackCString2Id,
+ integerZeroId, integerPlusOneId,
+ integerPlusTwoId, integerMinusOneId,
+ int2IntegerId, addr2IntegerId
+ )
+import Type ( Type, splitAlgTyConApp_maybe,
+ isUnLiftedType, mkTyVarTy,
+ tidyType, tidyTypes, tidyTopType, tidyTyVar, tidyTyVars,
+ Type
+ )
+import Class ( Class, classSelIds )
+import TysWiredIn ( isIntegerTy )
import LiberateCase ( liberateCase )
-import MainMonad
-import Maybes
import SAT ( doStaticArgs )
-import SCCauto
-import SimplEnv ( UnfoldingGuidance(..), SwitchChecker(..) ) -- instances
---ANDY:
---import SimplHaskell ( coreToHaskell )
-import SimplMonad ( zeroSimplCount, showSimplCount, TickType, SimplCount )
-import SimplPgm ( simplifyPgm )
-import SimplVar ( leastItCouldCost )
-import Specialise
-import SpecTyFuns ( pprSpecErrs )
+import Specialise ( specProgram)
+import SpecEnv ( specEnvToList, specEnvFromList )
import StrictAnal ( saWwTopBinds )
-#if ! OMIT_FOLDR_BUILD
-import FoldrBuildWW
-import AnalFBWW
-#endif
-#if ! OMIT_DEFORESTER
-import Deforest ( deforestProgram )
-import DefUtils ( deforestable )
-#endif
-import TyVarEnv ( nullTyVarEnv )
-import SplitUniq
-import Unique
-import Util
+import Var ( TyVar, mkId )
+import Unique ( Unique, Uniquable(..),
+ ratioTyConKey, mkUnique, incrUnique, initTidyUniques
+ )
+import UniqSupply ( UniqSupply, splitUniqSupply, uniqFromSupply )
+import Constants ( tARGET_MIN_INT, tARGET_MAX_INT )
+import Util ( mapAccumL )
+import Bag
+import Maybes
+import IO ( hPutStr, stderr )
+import Outputable
\end{code}
\begin{code}
-core2core :: [CoreToDo] -- spec of what core-to-core passes to do
- -> (GlobalSwitch->SwitchResult)-- "global" command-line info lookup fn
- -> FAST_STRING -- module name (profiling only)
- -> PprStyle -- printing style (for debugging only)
- -> SplitUniqSupply -- a name supply
- -> [TyCon] -- local data tycons and tycon specialisations
- -> FiniteMap TyCon [[Maybe UniType]]
- -> [PlainCoreBinding] -- input...
- -> MainIO
- ([PlainCoreBinding], -- results: program, plus...
- IdEnv UnfoldingDetails, -- unfoldings to be exported from here
- SpecialiseData) -- specialisation data
-
-core2core core_todos sw_chkr module_name ppr_style us local_tycons tycon_specs binds
- = BSCC("Core2Core")
- if null core_todos then -- very rare, I suspect...
- -- well, we still must do some renumbering
- returnMn (
- (snd (instCoreBindings (mkUniqueSupplyGrimily us) binds), nullIdEnv, init_specdata)
- )
- else
- (if do_verbose_core2core then
- writeMn stderr "VERBOSE CORE-TO-CORE:\n"
- else returnMn ()) `thenMn_`
-
- -- better do the main business
- foldl_mn do_core_pass
- (binds, us, nullIdEnv, init_specdata, zeroSimplCount)
- core_todos
- `thenMn` \ (processed_binds, _, inline_env, spec_data, simpl_stats) ->
-
- (if switch_is_on D_simplifier_stats
- then trace ("Simplifier Stats:\n" ++ showSimplCount simpl_stats) (returnMn ())
- else returnMn ()
- ) `thenMn_`
-
-{- LATER:
- (if do_dump_core_passes
- then trace (unlines (
- (nOfThem 78 '-'
- : "Core2Core"
- : "+------------------------------+"
- : reverse [ " " ++ take (30::Int) (what ++ repeat ' ') ++ "|"
- | what <- simpl_whats ])
- ++ ["+------------------------------+"]))
- else \x -> x) -- to the end
--}
- returnMn (processed_binds, inline_env, spec_data)
- ESCC
+core2core :: [CoreToDo] -- Spec of what core-to-core passes to do
+ -> Module -- Module name (profiling only)
+ -> [Class] -- Local classes
+ -> UniqSupply -- A name supply
+ -> [CoreBind] -- Input
+ -> IO [CoreBind] -- Result
+
+core2core core_todos module_name classes us binds
+ = do
+ let (us1, us2) = splitUniqSupply us
+
+ -- Do the main business
+ processed_binds <- doCorePasses us1 binds core_todos
+
+ -- Do the post-simplification business
+ post_simpl_binds <- doPostSimplification us2 processed_binds
+
+ -- Do the final tidy-up
+ final_binds <- tidyCorePgm module_name classes post_simpl_binds
+
+ -- Return results
+ return final_binds
+
+doCorePasses us binds []
+ = return binds
+
+doCorePasses us binds (to_do : to_dos)
+ = do
+ let (us1, us2) = splitUniqSupply us
+ binds1 <- doCorePass us1 binds to_do
+ doCorePasses us2 binds1 to_dos
+
+doCorePass us binds (CoreDoSimplify sw_chkr) = _scc_ "Simplify" simplifyPgm sw_chkr us binds
+doCorePass us binds CoreLiberateCase = _scc_ "LiberateCase" liberateCase binds
+doCorePass us binds CoreDoFloatInwards = _scc_ "FloatInwards" floatInwards binds
+doCorePass us binds CoreDoFullLaziness = _scc_ "CoreFloating" floatOutwards us binds
+doCorePass us binds CoreDoStaticArgs = _scc_ "CoreStaticArgs" doStaticArgs us binds
+doCorePass us binds CoreDoStrictness = _scc_ "CoreStranal" saWwTopBinds us binds
+doCorePass us binds CoreDoSpecialising = _scc_ "Specialise" specProgram us binds
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsection{The driver for the simplifier}
+%* *
+%************************************************************************
+
+\begin{code}
+simplifyPgm :: (SimplifierSwitch -> SwitchResult)
+ -> UniqSupply
+ -> [CoreBind] -- Input
+ -> IO [CoreBind] -- New bindings
+
+simplifyPgm sw_chkr us binds
+ = do {
+ beginPass "Simplify";
+
+ (termination_msg, it_count, counts, binds') <- iteration us 1 zeroSimplCount binds;
+
+ dumpIfSet opt_D_simplifier_stats "Simplifier statistics"
+ (vcat [text termination_msg <+> text "after" <+> ppr it_count <+> text "iterations",
+ text "",
+ pprSimplCount counts]);
+
+ endPass "Simplify"
+ (opt_D_verbose_core2core && not opt_D_dump_simpl_iterations)
+ binds'
+ }
where
- init_specdata = initSpecData local_tycons tycon_specs
-
- switch_is_on = switchIsOn sw_chkr
-
- do_dump_core_passes = switch_is_on D_dump_core_passes -- an Andy flag
- do_verbose_core2core = switch_is_on D_verbose_core2core
-
- lib_case_threshold -- ToDo: HACK HACK HACK : FIX ME FIX ME FIX ME
- -- Use 4x a known threshold
- = case (intSwitchSet sw_chkr UnfoldingOverrideThreshold) of
- Nothing -> 4 * uNFOLDING_USE_THRESHOLD
- Just xx -> 4 * xx
-
- -------------
- core_linter = if switch_is_on DoCoreLinting
- then lintCoreBindings ppr_style
- else ( \ whodunnit spec_done binds -> binds )
-
- --------------
- do_core_pass info@(binds, us, inline_env, spec_data, simpl_stats) to_do
- = let
- (us1, us2) = splitUniqSupply us
- in
- case to_do of
- CoreDoSimplify simpl_sw_chkr
- -> BSCC("CoreSimplify")
- case (simplifyPgm binds sw_chkr simpl_sw_chkr simpl_stats us1) of
- (p, it_cnt, simpl_stats2)
- -> end_pass us2 p inline_env spec_data simpl_stats2 ("Simplify (" ++ show it_cnt ++ ")")
- ESCC
-
- CoreDoFoldrBuildWorkerWrapper
-#if OMIT_FOLDR_BUILD
- -> error "ERROR: CoreDoFoldrBuildWorkerWrapper: not built into compiler\n"
-#else
- -> BSCC("CoreDoFoldrBuildWorkerWrapper")
- end_pass us2 (mkFoldrBuildWW switch_is_on us1 binds) inline_env spec_data simpl_stats "FBWW"
- ESCC
-#endif
-
- CoreDoFoldrBuildWWAnal
-#if OMIT_FOLDR_BUILD
- -> error "ERROR: CoreDoFoldrBuildWWAnal: not built into compiler\n"
-#else
- -> BSCC("CoreDoFoldrBuildWWAnal")
- end_pass us2 (analFBWW switch_is_on binds) inline_env spec_data simpl_stats "AnalFBWW"
- ESCC
-#endif
-
- CoreLiberateCase
- -> BSCC("LiberateCase")
- case (liberateCase lib_case_threshold binds) of { binds2 ->
- end_pass us2 binds2 inline_env spec_data simpl_stats "LiberateCase"
- }
- ESCC
-
- CoreDoCalcInlinings1 -- avoid inlinings w/ cost-centres
- -> BSCC("CoreInlinings1")
- case (calcInlinings False sw_chkr inline_env binds) of { inline_env2 ->
- end_pass us2 binds inline_env2 spec_data simpl_stats "Calc Inlinings"
- } ESCC
-
- CoreDoCalcInlinings2 -- allow inlinings w/ cost-centres
- -> BSCC("CoreInlinings2")
- case (calcInlinings True sw_chkr inline_env binds) of { inline_env2 ->
- end_pass us2 binds inline_env2 spec_data simpl_stats "Calc Inlinings"
- } ESCC
-
- CoreDoFloatInwards
- -> BSCC("FloatInwards")
- end_pass us2 (floatInwards binds) inline_env spec_data simpl_stats "FloatIn"
- ESCC
-
- CoreDoFullLaziness
- -> BSCC("CoreFloating")
- case (floatOutwards switch_is_on us1 binds) of { p ->
- end_pass us2 p inline_env spec_data simpl_stats "FloatOut"
- } ESCC
-
- CoreDoPrintCore ->
- let
- printed = ppShow 80 (ppr ppr_style binds)
- strict [] a = a
- strict (s:ss) a | ord s == 0 = error "0 in output string"
- | otherwise = strict ss a
- in
- end_pass us2 (strict printed (trace ("PrintCore:\n" ++ printed) binds)) inline_env spec_data simpl_stats "Print"
-
-{- ANDY:
- CoreDoHaskPrint ->
- let
- printed = coreToHaskell binds
- strict [] a = a
- strict (s:ss) a | ord s == 0 = error "0 in output string"
- | otherwise = strict ss a
- in
- strict printed (trace ("PrintCore:\n" ++ printed) binds), inline_env, spec_data, simpl_stats, "PrintHask"
--}
-
- CoreDoStaticArgs
- -> BSCC("CoreStaticArgs")
- end_pass us2 (doStaticArgs binds us1) inline_env spec_data simpl_stats "SAT"
- -- Binds really should be dependency-analysed for static-
- -- arg transformation... Not to worry, they probably are.
- -- (I don't think it *dies* if they aren't [WDP 94/04/15])
- ESCC
-
- CoreDoStrictness
- -> BSCC("CoreStranal")
- end_pass us2 (saWwTopBinds us1 switch_is_on binds) inline_env spec_data simpl_stats "StrAnal"
- ESCC
-
- CoreDoSpecialising
- -> BSCC("Specialise")
- case (specProgram switch_is_on us1 binds spec_data) of {
- (p, spec_data2@(SpecData _ spec_noerrs _ _ _
- spec_errs spec_warn spec_tyerrs)) ->
-
- -- if we got errors, we die straight away
- (if not spec_noerrs ||
- (switch_is_on ShowImportSpecs && not (isEmptyBag spec_warn)) then
- writeMn stderr (ppShow 1000 {-pprCols-}
- (pprSpecErrs PprForUser spec_errs spec_warn spec_tyerrs))
- `thenMn_` writeMn stderr "\n"
- else
- returnMn ()) `thenMn_`
-
- (if not spec_noerrs then -- Stop here if specialisation errors occured
- exitMn 1
- else
- returnMn ()) `thenMn_`
-
- end_pass us2 p inline_env spec_data2 simpl_stats "Specialise"
- }
- ESCC
-
- CoreDoDeforest
-#if OMIT_DEFORESTER
- -> error "ERROR: CoreDoDeforest: not built into compiler\n"
-#else
- -> BSCC("Deforestation")
- case (deforestProgram sw_chkr binds us1) of { binds ->
- end_pass us2 binds inline_env spec_data simpl_stats "Deforestation"
- }
- ESCC
-#endif
-
- CoreDoAutoCostCentres
- -> BSCC("AutoSCCs")
- end_pass us2 (addAutoCostCentres sw_chkr module_name binds) inline_env spec_data simpl_stats "AutoSCCs"
- ESCC
-
- -------------------------------------------------
-
- end_pass us2 binds2 inline_env2
- spec_data2@(SpecData spec_done _ _ _ _ _ _ _)
- simpl_stats2 what
- = -- report verbosely, if required
- (if do_verbose_core2core then
- writeMn stderr ("\n*** "++what++":\n")
- `thenMn_`
- writeMn stderr (ppShow 1000
- (ppAboves (map (pprPlainCoreBinding ppr_style) binds2)))
- `thenMn_`
- writeMn stderr "\n"
- else
- returnMn ()) `thenMn_`
- let
- linted_binds = core_linter what spec_done binds2
- in
- returnMn
- (linted_binds, -- processed binds, possibly run thru CoreLint
- us2, -- UniqueSupply for the next guy
- inline_env2, -- possibly-updated inline env
- spec_data2, -- possibly-updated specialisation info
- simpl_stats2 -- accumulated simplifier stats
- )
-
--- here so it can be inlined...
-foldl_mn f z [] = returnMn z
-foldl_mn f z (x:xs) = f z x `thenMn` \ zz ->
- foldl_mn f zz xs
+ max_iterations = getSimplIntSwitch sw_chkr MaxSimplifierIterations
+ simpl_switch_is_on = switchIsOn sw_chkr
+
+ core_iter_dump binds | opt_D_verbose_core2core = pprCoreBindings binds
+ | otherwise = empty
+
+ iteration us iteration_no counts binds
+ = do {
+ -- Occurrence analysis
+ let { tagged_binds = _scc_ "OccAnal" occurAnalyseBinds simpl_switch_is_on binds };
+ dumpIfSet opt_D_dump_occur_anal "Occurrence analysis"
+ (pprCoreBindings tagged_binds);
+
+ -- Simplify
+ let { (binds', counts') = initSmpl sw_chkr us1 (simplTopBinds tagged_binds);
+ all_counts = counts `plusSimplCount` counts'
+ } ;
+
+ -- Stop if nothing happened; don't dump output
+ if isZeroSimplCount counts' then
+ return ("Simplifier reached fixed point", iteration_no, all_counts, binds')
+ else do {
+
+ -- Dump the result of this iteration
+ dumpIfSet opt_D_dump_simpl_iterations
+ ("Simplifier iteration " ++ show iteration_no
+ ++ " out of " ++ show max_iterations)
+ (vcat[pprSimplCount counts',
+ text "",
+ core_iter_dump binds']) ;
+
+ -- Stop if we've run out of iterations
+ if iteration_no == max_iterations then
+ do {
+ if max_iterations > 1 then
+ hPutStr stderr ("NOTE: Simplifier still going after " ++
+ show max_iterations ++
+ " iterations; bailing out.\n")
+ else return ();
+
+ return ("Simplifier baled out", iteration_no, all_counts, binds')
+ }
+
+ -- Else loop
+ else iteration us2 (iteration_no + 1) all_counts binds'
+ } }
+ where
+ (us1, us2) = splitUniqSupply us
+
+
+simplTopBinds binds = go binds `thenSmpl` \ (binds', _) ->
+ returnSmpl binds'
+ where
+ go [] = returnSmpl ([], ())
+ go (bind1 : binds) = simplBind bind1 (go binds)
\end{code}
---- ToDo: maybe move elsewhere ---
-For top-level, exported binders that either (a)~have been INLINEd by
-the programmer or (b)~are sufficiently ``simple'' that they should be
-inlined, we want to record this info in a suitable IdEnv.
+%************************************************************************
+%* *
+\subsection{Tidying core}
+%* *
+%************************************************************************
+
+Several tasks are done by @tidyCorePgm@
+
+1. Make certain top-level bindings into Globals. The point is that
+ Global things get externally-visible labels at code generation
+ time
-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.
-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.
+2. 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.]
-We also need to check that everything in the RHS (values and types)
-will be visible on the other side of an interface, too.
\begin{code}
-calcInlinings :: Bool -- True => inlinings with _scc_s are OK
- -> (GlobalSwitch -> SwitchResult)
- -> IdEnv UnfoldingDetails
- -> [PlainCoreBinding]
- -> IdEnv UnfoldingDetails
+tidyCorePgm :: Module -> [Class] -> [CoreBind] -> IO [CoreBind]
+tidyCorePgm mod local_classes binds_in
+ = do
+ beginPass "Tidy Core"
+ let (_, binds_out) = mapAccumL (tidyBind (Just mod)) init_tidy_env binds_in
+ endPass "Tidy Core" (opt_D_dump_simpl || opt_D_verbose_core2core) binds_out
+ where
+ -- Make sure to avoid the names of class operations
+ -- They don't have top-level bindings, so we won't see them
+ -- in binds_in; so we must initialise the tidy_env appropriately
+ --
+ -- We also make sure to avoid any exported binders. Consider
+ -- f{-u1-} = 1 -- Local decl
+ -- ...
+ -- f{-u2-} = 2 -- Exported decl
+ --
+ -- The second exported decl must 'get' the name 'f', so we
+ -- have to put 'f' in the avoids list before we get to the first
+ -- decl. Name.tidyName then does a no-op on exported binders.
+ init_tidy_env = (initTidyOccEnv avoids, emptyVarEnv)
+ avoids = [getOccName sel_id | cls <- local_classes,
+ sel_id <- classSelIds cls]
+ ++
+ [getOccName bndr | bind <- binds_in,
+ bndr <- bindersOf bind,
+ isExported bndr]
+
+tidyBind :: Maybe Module -- (Just m) for top level, Nothing for nested
+ -> TidyEnv
+ -> CoreBind
+ -> (TidyEnv, CoreBind)
+tidyBind maybe_mod env (NonRec bndr rhs)
+ = let
+ (env', bndr') = tidyBndr maybe_mod env bndr
+ rhs' = tidyExpr env rhs
+ in
+ (env', NonRec bndr' rhs')
-calcInlinings scc_s_OK sw_chkr inline_env_so_far top_binds
+tidyBind maybe_mod env (Rec pairs)
= let
- result = foldl calci inline_env_so_far top_binds
+ -- We use env' when tidying the rhss
+ -- When tidying the binder itself we may tidy it's
+ -- specialisations; if any of these mention other binders
+ -- in the group we should really feed env' to them too;
+ -- but that seems (a) unlikely and (b) a bit tiresome.
+ -- So I left it out for now
+
+ (bndrs, rhss) = unzip pairs
+ (env', bndrs') = mapAccumL (tidyBndr maybe_mod) env bndrs
+ rhss' = map (tidyExpr env') rhss
+ in
+ (env', Rec (zip bndrs' rhss'))
+
+tidyExpr env (Type ty) = Type (tidyType env ty)
+tidyExpr env (Con con args) = Con con (map (tidyExpr env) args)
+tidyExpr env (App f a) = App (tidyExpr env f) (tidyExpr env a)
+tidyExpr env (Note n e) = Note (tidyNote env n) (tidyExpr env e)
+
+tidyExpr env (Let b e) = Let b' (tidyExpr env' e)
+ where
+ (env', b') = tidyBind Nothing env b
+
+tidyExpr env (Case e b alts) = Case (tidyExpr env e) b' (map (tidyAlt env') alts)
+ where
+ (env', b') = tidyNestedBndr env b
+
+tidyExpr env (Var v) = case lookupVarEnv var_env v of
+ Just v' -> Var v'
+ Nothing -> Var v
+ where
+ (_, var_env) = env
+
+tidyExpr env (Lam b e) = Lam b' (tidyExpr env' e)
+ where
+ (env', b') = tidyNestedBndr env b
+
+tidyAlt env (con, vs, rhs) = (con, vs', tidyExpr env' rhs)
+ where
+ (env', vs') = mapAccumL tidyNestedBndr env vs
+
+tidyNote env (Coerce t1 t2) = Coerce (tidyType env t1) (tidyType env t2)
+\end{code}
+
+\begin{code}
+tidyBndr (Just mod) env id = tidyTopBndr mod env id
+tidyBndr Nothing env var = tidyNestedBndr env var
+
+tidyNestedBndr env tyvar
+ | isTyVar tyvar
+ = tidyTyVar env tyvar
+
+tidyNestedBndr env@(tidy_env, var_env) id
+ = -- Non-top-level variables
+ let
+ -- Give the Id a fresh print-name, *and* rename its type
+ name' = mkLocalName (getUnique id) occ'
+ (tidy_env', occ') = tidyOccName tidy_env (getOccName id)
+ ty' = tidyType env (idType id)
+ id' = mkUserId name' ty'
+ -- NB: This throws away the IdInfo of the Id, which we
+ -- no longer need. That means we don't need to
+ -- run over it with env, nor renumber it.
+ var_env' = extendVarEnv var_env id id'
+ in
+ ((tidy_env', var_env'), id')
+
+tidyTopBndr mod env@(tidy_env, var_env) id
+ = -- Top level variables
+ let
+ (tidy_env', name') = tidyTopName mod tidy_env (idName id)
+ ty' = tidyTopType (idType id)
+ idinfo' = tidyIdInfo env (idInfo id)
+ id' = mkId name' ty' (idDetails id) idinfo'
+ var_env' = extendVarEnv var_env id id'
in
- --pprTrace "inline env:\n" (ppAboves (map pp_item (getIdEnvMapping result)))
- result
+ ((tidy_env', var_env'), id')
+
+-- tidyIdInfo does these things:
+-- a) tidy the specialisation info (if any)
+-- b) zap a complicated ICanSafelyBeINLINEd pragma,
+-- c) zap the unfolding
+-- The latter two are to avoid space leaks
+
+tidyIdInfo env info
+ = info3
where
- pp_item (binder, details)
- = ppCat [ppr PprDebug binder, ppStr "=>", pp_det details]
- where
- pp_det NoUnfoldingDetails = ppStr "_N_"
- pp_det (IWantToBeINLINEd _) = ppStr "INLINE"
- pp_det (GeneralForm _ _ expr guide)
- = ppAbove (ppr PprDebug guide) (ppr PprDebug expr)
- pp_det other = ppStr "???"
-
- ------------
- switch_is_on = switchIsOn sw_chkr
-
- my_trace = if (switch_is_on ReportWhyUnfoldingsDisallowed)
- then trace
- else \ msg stuff -> stuff
-
- (unfolding_creation_threshold, explicit_creation_threshold)
- = case (intSwitchSet sw_chkr UnfoldingCreationThreshold) of
- Nothing -> (uNFOLDING_CREATION_THRESHOLD, False)
- Just xx -> (xx, True)
-
- unfold_use_threshold
- = case (intSwitchSet sw_chkr UnfoldingUseThreshold) of
- Nothing -> uNFOLDING_USE_THRESHOLD
- Just xx -> xx
-
- unfold_override_threshold
- = case (intSwitchSet sw_chkr UnfoldingOverrideThreshold) of
- Nothing -> uNFOLDING_OVERRIDE_THRESHOLD
- Just xx -> xx
-
- con_discount_weight = uNFOLDING_CON_DISCOUNT_WEIGHT
-
- calci inline_env (CoRec pairs)
- = foldl (calc True{-recursive-}) inline_env pairs
-
- calci inline_env bind@(CoNonRec 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
- && (guidance_says_don't || guidance_size_just_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
- --pprTrace "giving up on size:" (ppCat [ppr PprDebug binder, ppr PprDebug [rhs_mentions_an_unmentionable, explicit_INLINE_requested, guidance_says_don't, guidance_size_just_too_big]]) (
- 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.
- = --pprTrace "giving up on isWrapperFor:" (ppr PprDebug binder)
- 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_to_me
- -- 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
+ spec_items = specEnvToList (specInfo info)
+ spec_env' = specEnvFromList (map tidy_item spec_items)
+ info1 | null spec_items = info
+ | otherwise = spec_env' `setSpecInfo` info
+
+ info2 = case inlinePragInfo info of
+ ICanSafelyBeINLINEd _ _ -> NoInlinePragInfo `setInlinePragInfo` info1
+ other -> info1
+
+ info3 = noUnfolding `setUnfoldingInfo` info2
+
+ tidy_item (tyvars, tys, rhs)
+ = (tyvars', tidyTypes env' tys, tidyExpr env rhs)
+ where
+ (env', tyvars') = tidyTyVars env tyvars
+\end{code}
- 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_says_don't = case guidance of { UnfoldNever -> True; _ -> False }
-
- guidance_size
- = case guidance of
- UnfoldAlways -> 0 -- *extremely* small
- EssentialUnfolding -> 0 -- ditto
- UnfoldIfGoodArgs _ _ _ size -> size
-
- guidance_size_just_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
- UnfoldNever -> False -- debugging only (ToDo:rm)
- 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_to_me then
- False -- probably a data value; we'd like the
- -- other guy to see the value, even if
- -- s/he doesn't unfold it.
- 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_arg_tys
- = let
- (_, val_binders, _) = digForLambdas rhs
- in
- map getIdUniType val_binders
-
- rhs_looks_like_a_data_val_to_me
- = let
- (_,val_binders,body) = digForLambdas rhs
- in
- case (val_binders, body) of
- ([], CoCon _ _ _) -> True
- other -> False
-
- (mentioned_ids, _, _, mentions_litlit)
- = mentionedInUnfolding (\x -> x) rhs
-
- rhs_mentions_an_unmentionable
- = --pprTrace "mentions:" (ppCat [ppr PprDebug binder, ppr PprDebug [(i,unfoldingUnfriendlyId i) | i <- mentioned_ids ]]) (
- any unfoldingUnfriendlyId mentioned_ids
- || mentions_litlit
- --)
- -- ToDo: probably need to chk tycons/classes...
-
- mentions_no_other_ids = null 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 = switch_is_on 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!
+
+
+%************************************************************************
+%* *
+\subsection{PostSimplification}
+%* *
+%************************************************************************
+
+Several tasks are performed by the post-simplification pass
+
+1. Make the representation of NoRep literals explicit, and
+ float their bindings to the top level. We only do the floating
+ part for NoRep lits inside a lambda (else no gain). We need to
+ take care with let x = "foo" in e
+ that we don't end up with a silly binding
+ let x = y in e
+ with a floated "foo". What a bore.
+
+2. *Mangle* cases involving par# in the discriminant. The unfolding
+ for par in PrelConc.lhs include case expressions with integer
+ results solely to fool the strictness analyzer, the simplifier,
+ and anyone else who might want to fool with the evaluation order.
+ At this point in the compiler our evaluation order is safe.
+ Therefore, we convert expressions of the form:
+
+ case par# e of
+ 0# -> rhs
+ _ -> parError#
+ ==>
+ case par# e of
+ _ -> rhs
+
+ fork# isn't handled like this - it's an explicit IO operation now.
+ The reason is that fork# returns a ThreadId#, which gets in the
+ way of the above scheme. And anyway, IO is the only guaranteed
+ way to enforce ordering --SDM.
+
+3. Mangle cases involving seq# in the discriminant. Up to this
+ point, seq# will appear like this:
+
+ case seq# e of
+ 0# -> seqError#
+ _ -> ...
+
+ where the 0# branch is purely to bamboozle the strictness analyser
+ (see case 4 above). This code comes from an unfolding for 'seq'
+ in Prelude.hs. We translate this into
+
+ case e of
+ _ -> ...
+
+ Now that the evaluation order is safe.
+
+4. 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. It does eta
+ on the RHSs of bindings but not the RHSs of case alternatives and
+ let bodies)
+
+
+------------------- NOT DONE ANY MORE ------------------------
+[March 98] Indirections are now elimianted by the occurrence analyser
+1. Eliminate indirections. The point here is to transform
+ x_local = E
+ x_exported = x_local
+ ==>
+ x_exported = E
+
+[Dec 98] [Not now done because there is no penalty in the code
+ generator for using the former form]
+2. Convert
+ case x of {...; x' -> ...x'...}
+ ==>
+ case x of {...; _ -> ...x... }
+ See notes in SimplCase.lhs, near simplDefault for the reasoning here.
+--------------------------------------------------------------
+
+Special case
+~~~~~~~~~~~~
+
+NOT ENABLED AT THE MOMENT (because the floated Ids are global-ish
+things, and we need local Ids for non-floated stuff):
+
+ Don't float stuff out of a binder that's marked as a bottoming Id.
+ Reason: it doesn't do any good, and creates more CAFs that increase
+ the size of SRTs.
+
+eg.
+
+ f = error "string"
+
+is translated to
+
+ f' = unpackCString# "string"
+ f = error f'
+
+hence f' and f become CAFs. Instead, the special case for
+tidyTopBinding below makes sure this comes out as
+
+ f = let f' = unpackCString# "string" in error f'
+
+and we can safely ignore f as a CAF, since it can only ever be entered once.
+
+
+
+\begin{code}
+doPostSimplification :: UniqSupply -> [CoreBind] -> IO [CoreBind]
+doPostSimplification us binds_in
+ = do
+ beginPass "Post-simplification pass"
+ let binds_out = initPM us (postSimplTopBinds binds_in)
+ endPass "Post-simplification pass" opt_D_verbose_core2core binds_out
+
+postSimplTopBinds :: [CoreBind] -> PostM [CoreBind]
+postSimplTopBinds binds
+ = mapPM postSimplTopBind binds `thenPM` \ binds' ->
+ returnPM (bagToList (unionManyBags binds'))
+
+postSimplTopBind :: CoreBind -> PostM (Bag CoreBind)
+postSimplTopBind (NonRec bndr rhs)
+ | isBottomingId bndr -- Don't lift out floats for bottoming Ids
+ -- See notes above
+ = getFloatsPM (postSimplExpr rhs) `thenPM` \ (rhs', floats) ->
+ returnPM (unitBag (NonRec bndr (foldrBag Let rhs' floats)))
+
+postSimplTopBind bind
+ = getFloatsPM (postSimplBind bind) `thenPM` \ (bind', floats) ->
+ returnPM (floats `snocBag` bind')
+
+postSimplBind (NonRec bndr rhs)
+ = postSimplExpr rhs `thenPM` \ rhs' ->
+ returnPM (NonRec bndr rhs')
+
+postSimplBind (Rec pairs)
+ = mapPM postSimplExpr rhss `thenPM` \ rhss' ->
+ returnPM (Rec (bndrs `zip` rhss'))
+ where
+ (bndrs, rhss) = unzip pairs
+\end{code}
+
+
+Expressions
+~~~~~~~~~~~
+\begin{code}
+postSimplExpr (Var v) = returnPM (Var v)
+postSimplExpr (Type ty) = returnPM (Type ty)
+
+postSimplExpr (App fun arg)
+ = postSimplExpr fun `thenPM` \ fun' ->
+ postSimplExpr arg `thenPM` \ arg' ->
+ returnPM (App fun' arg')
+
+postSimplExpr (Con (Literal lit) args)
+ = ASSERT( null args )
+ litToRep lit `thenPM` \ (lit_ty, lit_expr) ->
+ getInsideLambda `thenPM` \ in_lam ->
+ if in_lam && not (exprIsTrivial lit_expr) then
+ -- It must have been a no-rep literal with a
+ -- non-trivial representation; and we're inside a lambda;
+ -- so float it to the top
+ addTopFloat lit_ty lit_expr `thenPM` \ v ->
+ returnPM (Var v)
+ else
+ returnPM lit_expr
+
+postSimplExpr (Con con args)
+ = mapPM postSimplExpr args `thenPM` \ args' ->
+ returnPM (Con con args')
+
+postSimplExpr (Lam bndr body)
+ = insideLambda bndr $
+ postSimplExpr body `thenPM` \ body' ->
+ returnPM (Lam bndr body')
+
+postSimplExpr (Let bind body)
+ = postSimplBind bind `thenPM` \ bind' ->
+ postSimplExprEta body `thenPM` \ body' ->
+ returnPM (Let bind' body')
+
+postSimplExpr (Note note body)
+ = postSimplExprEta body `thenPM` \ body' ->
+ returnPM (Note note body')
+
+-- seq#: see notes above.
+-- NB: seq# :: forall a. a -> Int#
+postSimplExpr (Case scrut@(Con (PrimOp SeqOp) [Type ty, e]) bndr alts)
+ = postSimplExpr e `thenPM` \ e' ->
+ let
+ -- The old binder can't have been used, so we
+ -- can gaily re-use it (yuk!)
+ new_bndr = setIdType bndr ty
+ in
+ postSimplExprEta default_rhs `thenPM` \ rhs' ->
+ returnPM (Case e' new_bndr [(DEFAULT,[],rhs')])
+ where
+ (other_alts, maybe_default) = findDefault alts
+ Just default_rhs = maybe_default
+
+-- par#: see notes above.
+postSimplExpr (Case scrut@(Con (PrimOp op) args) bndr alts)
+ | funnyParallelOp op && maybeToBool maybe_default
+ = postSimplExpr scrut `thenPM` \ scrut' ->
+ postSimplExprEta default_rhs `thenPM` \ rhs' ->
+ returnPM (Case scrut' bndr [(DEFAULT,[],rhs')])
+ where
+ (other_alts, maybe_default) = findDefault alts
+ Just default_rhs = maybe_default
+
+postSimplExpr (Case scrut case_bndr alts)
+ = postSimplExpr scrut `thenPM` \ scrut' ->
+ mapPM ps_alt alts `thenPM` \ alts' ->
+ returnPM (Case scrut' case_bndr alts')
+ where
+ ps_alt (con,bndrs,rhs) = postSimplExprEta rhs `thenPM` \ rhs' ->
+ returnPM (con, bndrs, rhs')
+
+postSimplExprEta e = postSimplExpr e `thenPM` \ e' ->
+ returnPM (etaCoreExpr e')
+\end{code}
+
+\begin{code}
+funnyParallelOp ParOp = True
+funnyParallelOp _ = False
+\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 -> PostM (Type, CoreExpr)
+
+litToRep (NoRepStr s ty)
+ = returnPM (ty, rhs)
+ where
+ rhs = if (any is_NUL (_UNPK_ s))
+
+ then -- Must cater for NULs in literal string
+ mkApps (Var unpackCString2Id)
+ [mkLit (MachStr s),
+ mkLit (mkMachInt (toInteger (_LENGTH_ s)))]
+
+ else -- No NULs in the string
+ App (Var unpackCStringId) (mkLit (MachStr s))
+
+ is_NUL c = c == '\0'
\end{code}
-ANDY, on the hatred of the check above; why obliterate it? Consider
+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)
+ = returnPM (integer_ty, rhs)
+ where
+ rhs | i == 0 = Var integerZeroId -- Extremely convenient to look out for
+ | i == 1 = Var integerPlusOneId -- a few very common Integer literals!
+ | i == 2 = Var integerPlusTwoId
+ | i == (-1) = Var integerMinusOneId
+
+ | i > tARGET_MIN_INT && -- Small enough, so start from an Int
+ i < tARGET_MAX_INT
+ = App (Var int2IntegerId) (Con (Literal (mkMachInt i)) [])
+
+ | otherwise -- Big, so start from a string
+ = App (Var addr2IntegerId) (Con (Literal (MachStr (_PK_ (show i)))) [])
+
+
+litToRep (NoRepRational r rational_ty)
+ = postSimplExpr (mkLit (NoRepInteger (numerator r) integer_ty)) `thenPM` \ num_arg ->
+ postSimplExpr (mkLit (NoRepInteger (denominator r) integer_ty)) `thenPM` \ denom_arg ->
+ returnPM (rational_ty, mkConApp ratio_data_con [Type integer_ty, num_arg, denom_arg])
+ where
+ (ratio_data_con, integer_ty)
+ = case (splitAlgTyConApp_maybe rational_ty) of
+ Just (tycon, [i_ty], [con])
+ -> ASSERT(isIntegerTy i_ty && getUnique tycon == ratioTyConKey)
+ (con, i_ty)
+
+ _ -> (panic "ratio_data_con", panic "integer_ty")
+
+litToRep other_lit = returnPM (literalType other_lit, mkLit other_lit)
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsection{The monad}
+%* *
+%************************************************************************
+
+\begin{code}
+type PostM a = Bool -- True <=> inside a *value* lambda
+ -> (UniqSupply, Bag CoreBind) -- Unique supply and Floats in
+ -> (a, (UniqSupply, Bag CoreBind))
+
+initPM :: UniqSupply -> PostM a -> a
+initPM us m
+ = case m False {- not inside lambda -} (us, emptyBag) of
+ (result, _) -> result
+
+returnPM v in_lam usf = (v, usf)
+thenPM m k in_lam usf = case m in_lam usf of
+ (r, usf') -> k r in_lam usf'
+
+mapPM f [] = returnPM []
+mapPM f (x:xs) = f x `thenPM` \ r ->
+ mapPM f xs `thenPM` \ rs ->
+ returnPM (r:rs)
+
+insideLambda :: CoreBndr -> PostM a -> PostM a
+insideLambda bndr m in_lam usf | isId bndr = m True usf
+ | otherwise = m in_lam usf
+
+getInsideLambda :: PostM Bool
+getInsideLambda in_lam usf = (in_lam, usf)
+
+getFloatsPM :: PostM a -> PostM (a, Bag CoreBind)
+getFloatsPM m in_lam (us, floats)
+ = let
+ (a, (us', floats')) = m in_lam (us, emptyBag)
+ in
+ ((a, floats'), (us', floats))
+
+addTopFloat :: Type -> CoreExpr -> PostM Id
+addTopFloat lit_ty lit_rhs in_lam (us, floats)
+ = let
+ (us1, us2) = splitUniqSupply us
+ uniq = uniqFromSupply us1
+ lit_id = mkSysLocal SLIT("lf") uniq lit_ty
+ in
+ (lit_id, (us2, floats `snocBag` NonRec lit_id lit_rhs))
+\end{code}
- head xs = foldr (\ x _ -> x) (_|_) xs
-This then is exported via a pragma. However,
-*if* you include the extra code above, you will
-export the non-foldr/build version.
projects / ghc-hetmet.git / blobdiff