core expression with (hopefully) improved usage information.
\begin{code}
-{-# OPTIONS -w #-}
--- The above warning supression flag is a temporary kludge.
--- While working on this module you are encouraged to remove it and fix
--- any warnings in the module. See
--- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
--- for details
-
module OccurAnal (
occurAnalysePgm, occurAnalyseExpr
) where
+-- XXX This define is a bit of a hack, and should be done more nicely
+#define FAST_STRING_NOT_NEEDED 1
#include "HsVersions.h"
import CoreSyn
import CoreUtils ( exprIsTrivial, isDefaultAlt )
import Id
import IdInfo
-import BasicTypes ( OccInfo(..), isOneOcc, InterestingCxt )
+import BasicTypes
import VarSet
import VarEnv
import Digraph ( stronglyConnCompR, SCC(..) )
import PrelNames ( buildIdKey, foldrIdKey, runSTRepIdKey, augmentIdKey )
import Unique ( Unique )
-import UniqFM ( keysUFM, intersectsUFM, intersectUFM_C, foldUFM_Directly )
+import UniqFM ( keysUFM, intersectUFM_C, foldUFM_Directly )
import Util ( mapAndUnzip )
import Outputable
= snd (go initOccEnv binds)
where
go :: OccEnv -> [CoreBind] -> (UsageDetails, [CoreBind])
- go env []
+ go _ []
= (emptyDetails, [])
go env (bind:binds)
= (final_usage, bind' ++ binds')
| otherwise = Rec (concatMap reOrderRec (stronglyConnCompR loop_breaker_edges))
where -- See Note [Choosing loop breakers] for looop_breker_edges
loop_breaker_edges = map mk_node cycle
- mk_node (details@(bndr, rhs, rhs_fvs), k, _) = (details, k, new_ks)
+ mk_node (details@(_bndr, _rhs, rhs_fvs), k, _) = (details, k, new_ks)
where
new_ks = keysUFM (extendFvs rule_fv_env rhs_fvs rhs_fvs)
-- This loop looks for the bind with the lowest score
-- to pick as the loop breaker. The rest accumulate in
- choose_loop_breaker (details,_,_) loop_sc acc []
+ choose_loop_breaker (details,_,_) _loop_sc acc []
= (details, acc) -- Done
choose_loop_breaker loop_bind loop_sc acc (bind : binds)
| otherwise = 0
inlineCandidate :: Id -> CoreExpr -> Bool
- inlineCandidate id (Note InlineMe _) = True
- inlineCandidate id rhs = isOneOcc (idOccInfo id)
+ inlineCandidate _ (Note InlineMe _) = True
+ inlineCandidate id _ = isOneOcc (idOccInfo id)
-- Note [conapp]
--
-- Note [Closure conversion]
is_con_app (Var v) = isDataConWorkId v
is_con_app (App f _) = is_con_app f
- is_con_app (Lam b e) = is_con_app e
+ is_con_app (Lam _ e) = is_con_app e
is_con_app (Note _ e) = is_con_app e
- is_con_app other = False
+ is_con_app _ = False
makeLoopBreaker :: Bool -> Id -> Id
-- Set the loop-breaker flag
certainly_inline id = case idOccInfo id of
OneOcc in_lam one_br _ -> not in_lam && one_br
- other -> False
+ _ -> False
\end{code}
-> (UsageDetails, -- Gives info only about the "interesting" Ids
CoreExpr)
-occAnal env (Type t) = (emptyDetails, Type t)
+occAnal _ (Type t) = (emptyDetails, Type t)
occAnal env (Var v) = (mkOneOcc env v False, Var v)
-- At one stage, I gathered the idRuleVars for v here too,
-- which in a way is the right thing to do.
Constructors are rather like lambdas in this way.
\begin{code}
-occAnal env expr@(Lit lit) = (emptyDetails, expr)
+occAnal _ expr@(Lit _) = (emptyDetails, expr)
\end{code}
\begin{code}
(mapVarEnv markMany usage, Note InlineMe body')
}
-occAnal env (Note note@(SCC cc) body)
+occAnal env (Note note@(SCC _) body)
= case occAnal env body of { (usage, body') ->
(mapVarEnv markInsideSCC usage, Note note body')
}
\end{code}
\begin{code}
-occAnal env app@(App fun arg)
- = occAnalApp env (collectArgs app) False
+occAnal env app@(App _ _)
+ = occAnalApp env (collectArgs app)
-- Ignore type variables altogether
-- (a) occurrences inside type lambdas only not marked as InsideLam
-- (b) type variables not in environment
-occAnal env expr@(Lam x body) | isTyVar x
+occAnal env (Lam x body) | isTyVar x
= case occAnal env body of { (body_usage, body') ->
(body_usage, Lam x body')
}
occ_anal_scrut (Var v) (alt1 : other_alts)
| not (null other_alts) || not (isDefaultAlt alt1)
= (mkOneOcc env v True, Var v)
- occ_anal_scrut scrut alts = occAnal vanillaCtxt scrut
+ occ_anal_scrut scrut _alts = occAnal vanillaCtxt scrut
-- No need for rhsCtxt
occAnal env (Let bind body)
case occAnalBind env bind body_usage of { (final_usage, new_binds) ->
(final_usage, mkLets new_binds body') }}
-occAnalArgs env args
+occAnalArgs :: OccEnv -> [CoreExpr] -> (UsageDetails, [CoreExpr])
+occAnalArgs _env args
= case mapAndUnzip (occAnal arg_env) args of { (arg_uds_s, args') ->
(foldr (+++) emptyDetails arg_uds_s, args')}
where
the "build hack" to work.
\begin{code}
-occAnalApp env (Var fun, args) is_rhs
+occAnalApp :: OccEnv
+ -> (Expr CoreBndr, [Arg CoreBndr])
+ -> (UsageDetails, Expr CoreBndr)
+occAnalApp env (Var fun, args)
= case args_stuff of { (args_uds, args') ->
let
final_args_uds = markRhsUds env is_pap args_uds
| otherwise = occAnalArgs env args
-occAnalApp env (fun, args) is_rhs
+occAnalApp env (fun, args)
= case occAnal (addAppCtxt env args) fun of { (fun_uds, fun') ->
-- The addAppCtxt is a bit cunning. One iteration of the simplifier
-- often leaves behind beta redexs like
where
arg_env = vanillaCtxt
- go n [] = (emptyDetails, []) -- Too few args
+ go _ [] = (emptyDetails, []) -- Too few args
go 1 (arg:args) -- The magic arg
= case occAnal (setCtxt arg_env ctxt) arg of { (arg_uds, arg') ->
isDeadBinder in Simplify.mkDupableAlt
\begin{code}
-occAnalAlt env case_bndr (con, bndrs, rhs)
+occAnalAlt :: OccEnv
+ -> CoreBndr
+ -> CoreAlt
+ -> (UsageDetails, Alt IdWithOccInfo)
+occAnalAlt env _case_bndr (con, bndrs, rhs)
= case occAnal env rhs of { (rhs_usage, rhs') ->
let
(final_usage, tagged_bndrs) = tagBinders rhs_usage bndrs
initOccEnv :: OccEnv
initOccEnv = OccEnv OccRhs []
+vanillaCtxt :: OccEnv
vanillaCtxt = OccEnv OccVanilla []
+
+rhsCtxt :: OccEnv
rhsCtxt = OccEnv OccRhs []
+isRhsEnv :: OccEnv -> Bool
isRhsEnv (OccEnv OccRhs _) = True
isRhsEnv (OccEnv OccVanilla _) = False
-- linearity context knows that c,n are one-shot, and it records that fact in
-- the binder. This is useful to guide subsequent float-in/float-out tranformations
-oneShotGroup (OccEnv encl ctxt) bndrs
+oneShotGroup (OccEnv _encl ctxt) bndrs
= go ctxt bndrs []
where
- go ctxt [] rev_bndrs = reverse rev_bndrs
+ go _ [] rev_bndrs = reverse rev_bndrs
go (lin_ctxt:ctxt) (bndr:bndrs) rev_bndrs
| isId bndr = go ctxt bndrs (bndr':rev_bndrs)
go ctxt (bndr:bndrs) rev_bndrs = go ctxt bndrs (bndr:rev_bndrs)
+addAppCtxt :: OccEnv -> [Arg CoreBndr] -> OccEnv
addAppCtxt (OccEnv encl ctxt) args
= OccEnv encl (replicate (valArgCount args) True ++ ctxt)
\end{code}
= plusVarEnv_C addOccInfo usage (unitVarEnv id info)
-- ToDo: make this more efficient
+emptyDetails :: UsageDetails
emptyDetails = (emptyVarEnv :: UsageDetails)
usedIn :: Id -> UsageDetails -> Bool
| isTyVar bndr = bndr
| isExportedId bndr = case idOccInfo bndr of
NoOccInfo -> bndr
- other -> setIdOccInfo bndr NoOccInfo
+ _ -> setIdOccInfo bndr NoOccInfo
-- Don't use local usage info for visible-elsewhere things
-- BUT *do* erase any IAmALoopBreaker annotation, because we're
-- about to re-generate it and it shouldn't be "sticky"
\begin{code}
mkOneOcc :: OccEnv -> Id -> InterestingCxt -> UsageDetails
-mkOneOcc env id int_cxt
+mkOneOcc _env id int_cxt
| isLocalId id = unitVarEnv id (OneOcc False True int_cxt)
| otherwise = emptyDetails
markMany, markInsideLam, markInsideSCC :: OccInfo -> OccInfo
markMany IAmDead = IAmDead
-markMany other = NoOccInfo
+markMany _ = NoOccInfo
markInsideSCC occ = markMany occ
addOccInfo IAmDead info2 = info2
addOccInfo info1 IAmDead = info1
-addOccInfo info1 info2 = NoOccInfo
+addOccInfo _ _ = NoOccInfo
-- (orOccInfo orig new) is used
-- when combining occurrence info from branches of a case
orOccInfo IAmDead info2 = info2
orOccInfo info1 IAmDead = info1
-orOccInfo (OneOcc in_lam1 one_branch1 int_cxt1)
- (OneOcc in_lam2 one_branch2 int_cxt2)
+orOccInfo (OneOcc in_lam1 _ int_cxt1)
+ (OneOcc in_lam2 _ int_cxt2)
= OneOcc (in_lam1 || in_lam2)
False -- False, because it occurs in both branches
(int_cxt1 && int_cxt2)
-orOccInfo info1 info2 = NoOccInfo
+orOccInfo _ _ = NoOccInfo
\end{code}
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