%
-% (c) The AQUA Project, Glasgow University, 1993-1995
+% (c) The AQUA Project, Glasgow University, 1993-1996
%
-\section[SimplPgm]{Interface to the ``new'' simplifier}
+\section[SimplPgm]{Interface to the simplifier}
\begin{code}
#include "HsVersions.h"
module SimplPgm ( simplifyPgm ) where
-import Type ( getTyVarMaybe )
-import CmdLineOpts ( switchIsOn, intSwitchSet,
- GlobalSwitch(..), SimplifierSwitch(..)
+IMP_Ubiq(){-uitous-}
+
+import CmdLineOpts ( opt_D_verbose_core2core,
+ switchIsOn, SimplifierSwitch(..)
+ )
+import CoreSyn
+import CoreUnfold ( SimpleUnfolding )
+import CoreUtils ( substCoreExpr )
+import Id ( mkIdEnv, lookupIdEnv, SYN_IE(IdEnv),
+ GenId{-instance Ord3-}
)
-import Id ( externallyVisibleId )
-import IdInfo
-import Maybes ( catMaybes, Maybe(..) )
-import Outputable
+import Maybes ( catMaybes )
+import OccurAnal ( occurAnalyseBinds )
+import Pretty ( ppAboves, ppBesides, ppInt, ppChar, ppStr )
import SimplEnv
import SimplMonad
import Simplify ( simplTopBinds )
-import OccurAnal -- occurAnalyseBinds
-import UniqSupply
-import Util
+import TyVar ( nullTyVarEnv, SYN_IE(TyVarEnv) )
+import UniqSupply ( thenUs, returnUs, mapUs, splitUniqSupply, SYN_IE(UniqSM) )
+import Util ( isIn, isn'tIn, removeDups, pprTrace )
\end{code}
\begin{code}
-simplifyPgm :: [CoreBinding] -- input
- -> (GlobalSwitch->SwitchResult) -- switch lookup fns (global
- -> (SimplifierSwitch->SwitchResult) -- and this-simplification-specific)
- -> SimplCount -- info about how many times
- -- each transformation has occurred
+simplifyPgm :: [CoreBinding] -- input
+ -> (SimplifierSwitch->SwitchResult)
+ -> SimplCount -- info about how many times
+ -- each transformation has occurred
-> UniqSupply
-> ([CoreBinding], -- output
- Int, -- info about how much happened
- SimplCount) -- accumulated simpl stats
+ Int, -- info about how much happened
+ SimplCount) -- accumulated simpl stats
-simplifyPgm binds g_sw_chkr s_sw_chkr simpl_stats us
+simplifyPgm binds s_sw_chkr simpl_stats us
= case (splitUniqSupply us) of { (s1, s2) ->
case (initSmpl s1 (simpl_pgm 0 1 binds)) of { ((pgm2, it_count, simpl_stats2), _) ->
- case (tidy_top pgm2 s2) of { pgm3 ->
- (pgm3, it_count, combineSimplCounts simpl_stats simpl_stats2) }}}
+ (pgm2, it_count, combineSimplCounts simpl_stats simpl_stats2) }}
where
- global_switch_is_on = switchIsOn g_sw_chkr
simpl_switch_is_on = switchIsOn s_sw_chkr
occur_anal = occurAnalyseBinds
- max_simpl_iterations
- = case (intSwitchSet s_sw_chkr MaxSimplifierIterations) of
- Nothing -> 1 -- default
- Just max -> max
+ max_simpl_iterations = getSimplIntSwitch s_sw_chkr MaxSimplifierIterations
simpl_pgm :: Int -> Int -> [CoreBinding] -> SmplM ([CoreBinding], Int, SimplCount)
simpl_pgm n iterations pgm
= -- find out what top-level binders are used,
-- and prepare to unfold all the "simple" bindings
- -- pprTrace ("\niteration "++show iterations++":\n") (ppr PprDebug pgm) (
let
- tagged_pgm = BSCC("OccurBinds")
- occur_anal pgm global_switch_is_on simpl_switch_is_on
- ESCC
+ tagged_pgm = occur_anal pgm simpl_switch_is_on
in
-- do the business
simplTopBinds (nullSimplEnv s_sw_chkr) tagged_pgm `thenSmpl` \ new_pgm ->
show_status = pprTrace "NewSimpl: " (ppAboves [
ppBesides [ppInt iterations, ppChar '/', ppInt max_simpl_iterations],
ppStr (showSimplCount dr)
---DEBUG: , ppAboves (map (pprPlainCoreBinding PprDebug) new_pgm)
+--DEBUG: , ppAboves (map (pprCoreBinding PprDebug) new_pgm)
])
in
- (if global_switch_is_on D_verbose_core2core
+ (if opt_D_verbose_core2core
|| simpl_switch_is_on ShowSimplifierProgress
then show_status
else id)
else
simpl_pgm r (iterations + 1) new_pgm
)
- -- )
\end{code}
-In @tidy_top@, we look for things at the top-level of the form...
-\begin{verbatim}
-x_local = ....
-
-x_exported = x_local -- or perhaps...
-
-x_exported = /\ tyvars -> x_local tyvars -- where this is eta-reducible
-\end{verbatim}
-In cases we find like this, we go {\em backwards} and replace
-\tr{x_local} with \tr{x_exported}. This save a gratuitous jump
-(from \tr{x_exported} to \tr{x_local}), and makes strictness
-information propagate better.
-
-If more than one exported thing is equal to a local thing (i.e., the
-local thing really is shared), then obviously we give up.
-
-Strategy: first collect the info; then make a \tr{Id -> Id} mapping.
-Then blast the whole program (LHSs as well as RHSs) with it.
-
-\begin{code}
-type BlastEnv = IdEnv Id -- domain is local Ids; range is exported Ids
-
-not_elem = isn'tIn "undup"
-
-tidy_top :: [CoreBinding] -> UniqSM [CoreBinding]
-
-tidy_top binds_in
- = if null blast_alist then
- returnUs binds_in -- no joy there
- else
- -- pprTrace "undup output length:" (ppInt (length blast_alist)) (
- mapUs blast binds_in `thenUs` \ binds_maybe ->
- returnUs (catMaybes binds_maybe)
- -- )
- where
- blast_alist = undup (foldl find_cand [] binds_in)
- blast_id_env = mkIdEnv blast_alist
- blast_val_env= mkIdEnv [ (l, Var e) | (l,e) <- blast_alist ]
- blast_all_exps = map snd blast_alist
-
- ---------
- find_cand blast_list (Rec _) = blast_list -- recursively paranoid, as usual
-
- find_cand blast_list (NonRec binder rhs)
- = if not (isExported binder) then
- blast_list
- else
- case rhs_equiv_to_local_var rhs of
- Nothing -> blast_list
- Just local -> (local, binder) : blast_list -- tag it on
-
- ------------------------------------------
- -- if an Id appears >1 time in the domain,
- -- *all* occurrences must be expunged.
- undup :: [(Id, Id)] -> [(Id, Id)]
-
- undup blast_list
- = -- pprTrace "undup input length:" (ppInt (length blast_list)) (
- let
- (singles, dups) = removeDups compare blast_list
- list_of_dups = concat dups
- in
- [ s | s <- singles, s `not_elem` list_of_dups ]
- -- )
- where
- compare (x,_) (y,_) = x `cmp` y
-
- ------------------------------------------
- rhs_equiv_to_local_var (Var x)
- = if externallyVisibleId x then Nothing else Just x
-
- rhs_equiv_to_local_var expr = Nothing
-
- ------------------------------------------
- -- "blast" does the substitution:
- -- returns Nothing if a binding goes away
- -- returns "Just b" to give back a fixed-up binding
-
- blast :: CoreBinding -> UniqSM (Maybe CoreBinding)
-
- blast (Rec pairs)
- = mapUs blast_pr pairs `thenUs` \ blasted_pairs ->
- returnUs (Just (Rec blasted_pairs))
- where
- blast_pr (binder, rhs)
- = subst_CoreExprUS blast_val_env nullTyVarEnv rhs `thenUs` \ blasted_rhs ->
- returnUs (
- case lookupIdEnv blast_id_env binder of
- Just exportee -> (exportee, blasted_rhs)
- Nothing -> (binder, blasted_rhs)
- )
-
- blast (NonRec binder rhs)
- = if binder `is_elem` blast_all_exps then
- returnUs Nothing -- this binding dies!
- else
- subst_CoreExprUS blast_val_env nullTyVarEnv rhs `thenUs` \ blasted_rhs ->
- returnUs (Just (
- case lookupIdEnv blast_id_env binder of
- Just exportee -> NonRec exportee blasted_rhs
- Nothing -> NonRec binder blasted_rhs
- ))
- where
- is_elem = isIn "blast"
-
-subst_CoreExprUS e1 e2 rhs us = snd (substCoreExprUS e1 e2 rhs (mkUniqueSupplyGrimily us))
-\end{code}
projects / ghc-hetmet.git / blobdiff