%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
+% (c) The AQUA Project, Glasgow University, 1996-1998
%
-\section{Tidying up Core}
\begin{code}
module CoreTidy (
- tidyCorePgm, tidyExpr,
- tidyBndr, tidyBndrs
+ tidyExpr, tidyVarOcc, tidyRule, tidyRules
) where
#include "HsVersions.h"
-import CmdLineOpts ( DynFlags, DynFlag(..), opt_OmitInterfacePragmas, dopt )
import CoreSyn
-import CoreUnfold ( noUnfolding, mkTopUnfolding, okToUnfoldInHiFile )
-import CoreFVs ( ruleSomeFreeVars, exprSomeFreeVars )
-import CoreLint ( showPass, endPass )
+import CoreUtils ( exprArity )
+import Unify ( coreRefineTys )
+import DataCon ( DataCon, isVanillaDataCon )
+import Id ( Id, mkUserLocal, idInfo, setIdInfo, idUnique,
+ idType, setIdType )
+import IdInfo ( setArityInfo, vanillaIdInfo,
+ newStrictnessInfo, setAllStrictnessInfo,
+ newDemandInfo, setNewDemandInfo )
+import Type ( Type, tidyType, tidyTyVarBndr, substTy, mkOpenTvSubst )
+import Var ( Var, TyVar, varName )
import VarEnv
-import VarSet
-import Var ( Id, Var )
-import Id ( idType, idInfo, idName, isExportedId,
- mkVanillaId, mkId, isLocalId, omitIfaceSigForId,
- setIdStrictness, setIdDemandInfo,
- )
-import IdInfo ( mkIdInfo,
- IdFlavour(..), flavourInfo, ppFlavourInfo,
- specInfo, setSpecInfo,
- cprInfo, setCprInfo,
- inlinePragInfo, setInlinePragInfo, isNeverInlinePrag,
- strictnessInfo, setStrictnessInfo, isBottomingStrictness,
- unfoldingInfo, setUnfoldingInfo,
- demandInfo,
- occInfo, isLoopBreaker,
- workerInfo, setWorkerInfo, WorkerInfo(..)
- )
-import Name ( getOccName, nameOccName, globaliseName, setNameOcc,
- localiseName, mkLocalName, isGlobalName
- )
-import OccName ( TidyOccEnv, initTidyOccEnv, tidyOccName )
-import Type ( tidyTopType, tidyType, tidyTyVar )
-import Module ( Module, moduleName )
-import HscTypes ( PersistentCompilerState( pcs_PRS ), PersistentRenamerState( prsOrig ),
- OrigNameEnv( origNames ), OrigNameNameEnv
- )
-import Unique ( Uniquable(..) )
-import FiniteMap ( lookupFM, addToFM )
-import Maybes ( maybeToBool, orElse )
-import ErrUtils ( showPass )
+import UniqFM ( lookupUFM )
+import Name ( Name, getOccName )
+import OccName ( tidyOccName )
import SrcLoc ( noSrcLoc )
-import UniqFM ( mapUFM )
+import Maybes ( orElse )
import Outputable
-import List ( partition )
import Util ( mapAccumL )
\end{code}
-
-%************************************************************************
-%* *
-\subsection{What goes on}
-%* *
-%************************************************************************
-
-[SLPJ: 19 Nov 00]
-
-The plan is this.
-
-Step 1: Figure out external Ids
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-First we figure out which Ids are "external" Ids. An
-"external" Id is one that is visible from outside the compilation
-unit. These are
- a) the user exported ones
- b) ones mentioned in the unfoldings, workers,
- or rules of externally-visible ones
-This exercise takes a sweep of the bindings bottom to top. Actually,
-in Step 2 we're also going to need to know which Ids should be
-exported with their unfoldings, so we produce not an IdSet but an
-IdEnv Bool
-
-
-
-Step 2: Tidy the program
-~~~~~~~~~~~~~~~~~~~~~~~~
-Next we traverse the bindings top to bottom. For each top-level
-binder
-
- - Make all external Ids have Global names and vice versa
- This is used by the code generator to decide whether
- to make the label externally visible
-
- - Give external ids a "tidy" occurrence name. This means
- we can print them in interface files without confusing
- "x" (unique 5) with "x" (unique 10).
-
- - Give external Ids the same Unique as they had before
- if the name is in the renamer's name cache
-
- - Give the Id its final IdInfo; in ptic,
- * Its flavour becomes ConstantId, reflecting the fact that
- from now on we regard it as a constant, not local, Id
- * its unfolding, if it should have one
-
-Finally, substitute these new top-level binders consistently
-throughout, including in unfoldings. We also tidy binders in
-RHSs, so that they print nicely in interfaces.
-
-\begin{code}
-tidyCorePgm :: DynFlags -> Module
- -> PersistentCompilerState
- -> [CoreBind] -> [IdCoreRule]
- -> IO (PersistentCompilerState, [CoreBind], [IdCoreRule])
-tidyCorePgm dflags mod pcs binds_in orphans_in
- = do { showPass dflags "Tidy Core"
-
- ; let ext_ids = findExternalSet binds_in orphans_in
-
- ; let ((orig_env', occ_env, subst_env), binds_out)
- = mapAccumL (tidyTopBind mod ext_ids) init_tidy_env binds_in
-
- ; let orphans_out = tidyIdRules (occ_env,subst_env) orphans_in
-
- ; let pcs' = pcs { pcs_PRS = prs { prsOrig = orig { origNames = orig_env' }}}
-
- ; endPass dflags "Tidy Core" (dopt Opt_D_dump_simpl dflags ||
- dopt Opt_D_verbose_core2core dflags)
- binds_out
-
- ; return (pcs', binds_out, orphans_out)
- }
- where
- -- 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. tidyTopId then does a no-op on exported binders.
- prs = pcs_PRS pcs
- orig = prsOrig prs
- orig_env = origNames orig
-
- init_tidy_env = (orig_env, initTidyOccEnv avoids, emptyVarEnv)
- avoids = [getOccName bndr | bndr <- bindersOfBinds binds_in,
- isGlobalName (idName bndr)]
-\end{code}
-
-
-%************************************************************************
-%* *
-\subsection{Step 1: finding externals}
-%* *
-%************************************************************************
-
-\begin{code}
-findExternalSet :: [CoreBind] -> [IdCoreRule]
- -> IdEnv Bool -- True <=> show unfolding
- -- Step 1 from the notes above
-findExternalSet binds orphan_rules
- = foldr find init_needed binds
- where
- orphan_rule_ids :: IdSet
- orphan_rule_ids = unionVarSets [ ruleSomeFreeVars isIdAndLocal rule
- | (_, rule) <- orphan_rules]
- init_needed :: IdEnv Bool
- init_needed = mapUFM (\_ -> False) orphan_rule_ids
- -- The mapUFM is a bit cheesy. It is a cheap way
- -- to turn the set of orphan_rule_ids, which we use to initialise
- -- the sweep, into a mapping saying 'don't expose unfolding'
- -- (When we come to the binding site we may change our mind, of course.)
-
- find (NonRec id rhs) needed
- | need_id needed id = addExternal (id,rhs) needed
- | otherwise = needed
- find (Rec prs) needed = find_prs prs needed
-
- -- For a recursive group we have to look for a fixed point
- find_prs prs needed
- | null needed_prs = needed
- | otherwise = find_prs other_prs new_needed
- where
- (needed_prs, other_prs) = partition (need_pr needed) prs
- new_needed = foldr addExternal needed needed_prs
-
- -- The 'needed' set contains the Ids that are needed by earlier
- -- interface file emissions. If the Id isn't in this set, and isn't
- -- exported, there's no need to emit anything
- need_id needed_set id = id `elemVarEnv` needed_set || isExportedId id
- need_pr needed_set (id,rhs) = need_id needed_set id
-
-isIdAndLocal id = isId id && isLocalId id
-
-addExternal :: (Id,CoreExpr) -> IdEnv Bool -> IdEnv Bool
--- The Id is needed; extend the needed set
--- with it and its dependents (free vars etc)
-addExternal (id,rhs) needed
- = extendVarEnv (foldVarSet add_occ needed new_needed_ids)
- id show_unfold
- where
- add_occ id needed = extendVarEnv needed id False
- -- "False" because we don't know we need the Id's unfolding
- -- We'll override it later when we find the binding site
-
- new_needed_ids | opt_OmitInterfacePragmas = emptyVarSet
- | otherwise = worker_ids `unionVarSet`
- unfold_ids `unionVarSet`
- spec_ids
-
- idinfo = idInfo id
- dont_inline = isNeverInlinePrag (inlinePragInfo idinfo)
- loop_breaker = isLoopBreaker (occInfo idinfo)
- bottoming_fn = isBottomingStrictness (strictnessInfo idinfo)
- spec_ids = rulesRhsFreeVars (specInfo idinfo)
- worker_info = workerInfo idinfo
-
- -- Stuff to do with the Id's unfolding
- -- The simplifier has put an up-to-date unfolding
- -- in the IdInfo, but the RHS will do just as well
- unfolding = unfoldingInfo idinfo
- rhs_is_small = not (neverUnfold unfolding)
-
- -- We leave the unfolding there even if there is a worker
- -- In GHCI the unfolding is used by importers
- -- When writing an interface file, we omit the unfolding
- -- if there is a worker
- show_unfold = not bottoming_fn && -- Not necessary
- not dont_inline &&
- not loop_breaker &&
- rhs_is_small && -- Small enough
- okToUnfoldInHiFile rhs -- No casms etc
-
- unfold_ids | show_unfold = exprSomeFreeVars isIdAndLocal rhs
- | otherwise = emptyVarSet
-
- worker_ids = case worker_info of
- HasWorker work_id _ -> unitVarSet work_id
- otherwise -> emptyVarSet
-\end{code}
-
-
-%************************************************************************
-%* *
-\subsection{Step 2: top-level tidying}
-%* *
-%************************************************************************
-
-
-\begin{code}
-type TopTidyEnv = (OrigNameNameEnv, TidyOccEnv, VarEnv Var)
-
--- TopTidyEnv: when tidying we need to know
--- * orig_env: Any pre-ordained Names. These may have arisen because the
--- renamer read in an interface file mentioning M.$wf, say,
--- and assigned it unique r77. If, on this compilation, we've
--- invented an Id whose name is $wf (but with a different unique)
--- we want to rename it to have unique r77, so that we can do easy
--- comparisons with stuff from the interface file
-
--- * occ_env: The TidyOccEnv, which tells us which local occurrences are 'used'
-
--- * subst_env: A Var->Var mapping that substitutes the new Var for the old
-\end{code}
-
-
-\begin{code}
-tidyTopBind :: Module
- -> IdEnv Bool -- Domain = Ids that should be exernal
- -- True <=> their unfolding is external too
- -> TopTidyEnv -> CoreBind
- -> (TopTidyEnv, CoreBind)
-
-tidyTopBind mod ext_ids env (NonRec bndr rhs)
- = (env', NonRec bndr' rhs')
- where
- rhs' = tidyTopRhs env rhs
- (env', bndr') = tidyTopBinder mod ext_ids env rhs' env bndr
-
-tidyTopBind mod ext_ids env (Rec prs)
- = (final_env, Rec prs')
- where
- (final_env, prs') = mapAccumL do_one env prs
- do_one env (bndr,rhs) = (env', (bndr', rhs'))
- where
- rhs' = tidyTopRhs final_env rhs
- (env', bndr') = tidyTopBinder mod ext_ids final_env
- rhs env bndr
-
-tidyTopRhs :: TopTidyEnv -> CoreExpr -> CoreExpr
- -- Just an impedence matcher
-tidyTopRhs (_, occ_env, subst_env) rhs = tidyExpr (occ_env, subst_env) rhs
-
-tidyTopBinder :: Module -> IdEnv Bool
- -> TopTidyEnv -> CoreExpr
- -> TopTidyEnv -> Id -> (TopTidyEnv, Id)
-tidyTopBinder mod ext_ids env_idinfo rhs env@(orig_env, occ_env, subst_env) id
- | omitIfaceSigForId id -- Don't mess with constructors,
- = (env, id) -- record selectors, and the like
-
- | otherwise
- -- This function is the heart of Step 2
- -- The second env is the one to use for the IdInfo
- -- It's necessary because when we are dealing with a recursive
- -- group, a variable late in the group might be mentioned
- -- in the IdInfo of one early in the group
-
- -- The rhs is already tidied
-
- = ((orig_env', occ_env', subst_env'), id')
- where
- (orig_env', occ_env', name') = tidyTopName mod orig_env occ_env
- is_external
- (idName id)
- ty' = tidyTopType (idType id)
- idinfo' = tidyIdInfo env_idinfo is_external unfold_info id
- id' = mkId name' ty' idinfo'
- subst_env' = extendVarEnv subst_env id id'
-
- maybe_external = lookupVarEnv ext_ids id
- is_external = maybeToBool maybe_external
-
- -- Expose an unfolding if ext_ids tells us to
- show_unfold = maybe_external `orElse` False
- unfold_info | show_unfold = mkTopUnfolding rhs
- | otherwise = noUnfolding
-
-tidyIdInfo (_, occ_env, subst_env) is_external unfold_info id
- | opt_OmitInterfacePragmas || not is_external
- -- No IdInfo if the Id isn't external, or if we don't have -O
- = mkIdInfo new_flavour
- `setStrictnessInfo` strictnessInfo core_idinfo
- -- Keep strictness info; it's used by the code generator
-
- | otherwise
- = mkIdInfo new_flavour
- `setCprInfo` cprInfo core_idinfo
- `setStrictnessInfo` strictnessInfo core_idinfo
- `setInlinePragInfo` inlinePragInfo core_idinfo
- `setUnfoldingInfo` unfold_info
- `setWorkerInfo` tidyWorker tidy_env (workerInfo core_idinfo)
- `setSpecInfo` tidyRules tidy_env (specInfo core_idinfo)
- where
- tidy_env = (occ_env, subst_env)
- core_idinfo = idInfo id
-
- -- A DFunId must stay a DFunId, so that we can gather the
- -- DFunIds up later. Other local things become ConstantIds.
- new_flavour = case flavourInfo core_idinfo of
- VanillaId -> ConstantId
- ExportedId -> ConstantId
- DictFunId -> DictFunId
- flavour -> pprTrace "tidyIdInfo" (ppr id <+> ppFlavourInfo flavour)
- flavour
-
-tidyTopName mod orig_env occ_env external name
- | global && internal = (orig_env, occ_env, localiseName name)
- | local && internal = (orig_env, occ_env', setNameOcc name occ')
- | global && external = (orig_env, occ_env, name)
- | local && external = globalise
- where
- -- If we want to globalise a currently-local name, check
- -- whether we have already assigned a unique for it.
- -- If so, use it; if not, extend the table
- globalise = case lookupFM orig_env key of
- Just orig -> (orig_env, occ_env', orig)
- Nothing -> (addToFM orig_env key global_name, occ_env', global_name)
-
- (occ_env', occ') = tidyOccName occ_env (nameOccName name)
- key = (moduleName mod, occ')
- global_name = globaliseName (setNameOcc name occ') mod
- global = isGlobalName name
- local = not global
- internal = not external
-
-tidyIdRules :: TidyEnv -> [IdCoreRule] -> [IdCoreRule]
-tidyIdRules env rules
- = [ (tidyVarOcc env fn, tidyRule env rule) | (fn,rule) <- rules ]
-
-
-tidyWorker tidy_env (HasWorker work_id wrap_arity)
- = HasWorker (tidyVarOcc tidy_env work_id) wrap_arity
-tidyWorker tidy_env NoWorker
- = NoWorker
-
-tidyRules :: TidyEnv -> CoreRules -> CoreRules
-tidyRules env (Rules rules fvs)
- = Rules (map (tidyRule env) rules)
- (foldVarSet tidy_set_elem emptyVarSet fvs)
- where
- tidy_set_elem var new_set = extendVarSet new_set (tidyVarOcc env var)
-
-tidyRule :: TidyEnv -> CoreRule -> CoreRule
-tidyRule env rule@(BuiltinRule _) = rule
-tidyRule env (Rule name vars tpl_args rhs)
- = (Rule name vars' (map (tidyExpr env') tpl_args) (tidyExpr env' rhs))
- where
- (env', vars') = tidyBndrs env vars
-\end{code}
-
+This module contains "tidying" code for *nested* expressions, bindings, rules.
+The code for *top-level* bindings is in TidyPgm.
%************************************************************************
%* *
-\subsection{Step 2: inner tidying
+\subsection{Tidying expressions, rules}
%* *
%************************************************************************
\begin{code}
tidyBind :: TidyEnv
-> CoreBind
- -> (TidyEnv, CoreBind)
+ -> (TidyEnv, CoreBind)
+
tidyBind env (NonRec bndr rhs)
- = let
- (env', bndr') = tidyBndr env bndr
- rhs' = tidyExpr env' rhs
- -- We use env' when tidying the RHS even though it's not
- -- strictly necessary; it makes the tidied code pretty
- -- hard to read if we don't!
- in
- (env', NonRec bndr' rhs')
+ = tidyLetBndr env (bndr,rhs) =: \ (env', bndr') ->
+ (env', NonRec bndr' (tidyExpr env' rhs))
tidyBind env (Rec prs)
- = (final_env, Rec prs')
+ = mapAccumL tidyLetBndr env prs =: \ (env', bndrs') ->
+ map (tidyExpr env') (map snd prs) =: \ rhss' ->
+ (env', Rec (zip bndrs' rhss'))
+
+
+------------ Expressions --------------
+tidyExpr :: TidyEnv -> CoreExpr -> CoreExpr
+tidyExpr env (Var v) = Var (tidyVarOcc env v)
+tidyExpr env (Type ty) = Type (tidyType env ty)
+tidyExpr env (Lit lit) = Lit lit
+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)
+ = tidyBind env b =: \ (env', b') ->
+ Let b' (tidyExpr env' e)
+
+tidyExpr env (Case e b ty alts)
+ = tidyBndr env b =: \ (env', b) ->
+ Case (tidyExpr env e) b (tidyType env ty)
+ (map (tidyAlt b env') alts)
+
+tidyExpr env (Lam b e)
+ = tidyBndr env b =: \ (env', b) ->
+ Lam b (tidyExpr env' e)
+
+------------ Case alternatives --------------
+tidyAlt case_bndr env (DataAlt con, vs, rhs)
+ | not (isVanillaDataCon con) -- GADT case
+ = tidyBndrs env tvs =: \ (env1, tvs') ->
+ let
+ env2 = refineTidyEnv env con tvs' scrut_ty
+ in
+ tidyBndrs env2 ids =: \ (env3, ids') ->
+ (DataAlt con, tvs' ++ ids', tidyExpr env3 rhs)
+ where
+ (tvs, ids) = span isTyVar vs
+ scrut_ty = idType case_bndr
+
+tidyAlt case_bndr env (con, vs, rhs)
+ = tidyBndrs env vs =: \ (env', vs) ->
+ (con, vs, tidyExpr env' rhs)
+
+refineTidyEnv :: TidyEnv -> DataCon -> [TyVar] -> Type -> TidyEnv
+-- Refine the TidyEnv in the light of the type refinement from coreRefineTys
+refineTidyEnv tidy_env@(occ_env, var_env) con tvs scrut_ty
+ = case coreRefineTys con tvs scrut_ty of
+ Nothing -> tidy_env
+ Just (tv_subst, all_bound_here)
+ | all_bound_here -- Local type refinement only
+ -> tidy_env
+ | otherwise -- Apply the refining subst to the tidy env
+ -- This ensures that occurences have the most refined type
+ -- And that means that exprType will work right everywhere
+ -> (occ_env, mapVarEnv (refine subst) var_env)
+ where
+ subst = mkOpenTvSubst tv_subst
where
- (final_env, prs') = mapAccumL do_one env prs
- do_one env (bndr,rhs) = (env', (bndr', rhs'))
- where
- (env', bndr') = tidyBndr env bndr
- rhs' = tidyExpr final_env rhs
-
-tidyExpr env (Type ty) = Type (tidyType env ty)
-tidyExpr env (Lit lit) = Lit lit
-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 env b
-
-tidyExpr env (Case e b alts) = Case (tidyExpr env e) b' (map (tidyAlt env') alts)
- where
- (env', b') = tidyBndr env b
-
-tidyExpr env (Var v) = Var (tidyVarOcc env v)
-
-tidyExpr env (Lam b e) = Lam b' (tidyExpr env' e)
- where
- (env', b') = tidyBndr env b
-
-tidyAlt env (con, vs, rhs) = (con, vs', tidyExpr env' rhs)
- where
- (env', vs') = tidyBndrs env vs
+ refine subst var | isId var = setIdType var (substTy subst (idType var))
+ | otherwise = var
+------------ Notes --------------
tidyNote env (Coerce t1 t2) = Coerce (tidyType env t1) (tidyType env t2)
-
tidyNote env note = note
+
+------------ Rules --------------
+tidyRules :: TidyEnv -> [CoreRule] -> [CoreRule]
+tidyRules env [] = []
+tidyRules env (rule : rules)
+ = tidyRule env rule =: \ rule ->
+ tidyRules env rules =: \ rules ->
+ (rule : rules)
+
+tidyRule :: TidyEnv -> CoreRule -> CoreRule
+tidyRule env rule@(BuiltinRule {}) = rule
+tidyRule env rule@(Rule { ru_bndrs = bndrs, ru_args = args, ru_rhs = rhs,
+ ru_fn = fn, ru_rough = mb_ns })
+ = tidyBndrs env bndrs =: \ (env', bndrs) ->
+ map (tidyExpr env') args =: \ args ->
+ rule { ru_bndrs = bndrs, ru_args = args,
+ ru_rhs = tidyExpr env' rhs,
+ ru_fn = tidyNameOcc env fn,
+ ru_rough = map (fmap (tidyNameOcc env')) mb_ns }
\end{code}
%************************************************************************
%* *
-\subsection{Tidying up non-top-level binders}
+\subsection{Tidying non-top-level binders}
%* *
%************************************************************************
\begin{code}
-tidyVarOcc (_, var_env) v = case lookupVarEnv var_env v of
- Just v' -> v'
- Nothing -> v
+tidyNameOcc :: TidyEnv -> Name -> Name
+-- In rules and instances, we have Names, and we must tidy them too
+-- Fortunately, we can lookup in the VarEnv with a name
+tidyNameOcc (_, var_env) n = case lookupUFM var_env n of
+ Nothing -> n
+ Just v -> varName v
+tidyVarOcc :: TidyEnv -> Var -> Var
+tidyVarOcc (_, var_env) v = lookupVarEnv var_env v `orElse` v
+
+-- tidyBndr is used for lambda and case binders
tidyBndr :: TidyEnv -> Var -> (TidyEnv, Var)
-tidyBndr env var | isTyVar var = tidyTyVar env var
- | otherwise = tidyId env var
+tidyBndr env var
+ | isTyVar var = tidyTyVarBndr env var
+ | otherwise = tidyIdBndr env var
tidyBndrs :: TidyEnv -> [Var] -> (TidyEnv, [Var])
tidyBndrs env vars = mapAccumL tidyBndr env vars
-tidyId :: TidyEnv -> Id -> (TidyEnv, Id)
-tidyId env@(tidy_env, var_env) id
- = -- Non-top-level variables
+tidyLetBndr :: TidyEnv -> (Id, CoreExpr) -> (TidyEnv, Var)
+-- Used for local (non-top-level) let(rec)s
+tidyLetBndr env (id,rhs)
+ = ((tidy_env,new_var_env), final_id)
+ where
+ ((tidy_env,var_env), new_id) = tidyIdBndr env id
+
+ -- We need to keep around any interesting strictness and
+ -- demand info because later on we may need to use it when
+ -- converting to A-normal form.
+ -- eg.
+ -- f (g x), where f is strict in its argument, will be converted
+ -- into case (g x) of z -> f z by CorePrep, but only if f still
+ -- has its strictness info.
+ --
+ -- Similarly for the demand info - on a let binder, this tells
+ -- CorePrep to turn the let into a case.
+ --
+ -- Similarly arity info for eta expansion in CorePrep
+ --
+ final_id = new_id `setIdInfo` new_info
+ idinfo = idInfo id
+ new_info = vanillaIdInfo
+ `setArityInfo` exprArity rhs
+ `setAllStrictnessInfo` newStrictnessInfo idinfo
+ `setNewDemandInfo` newDemandInfo idinfo
+
+ -- Override the env we get back from tidyId with the new IdInfo
+ -- so it gets propagated to the usage sites.
+ new_var_env = extendVarEnv var_env id final_id
+
+-- Non-top-level variables
+tidyIdBndr :: TidyEnv -> Id -> (TidyEnv, Id)
+tidyIdBndr env@(tidy_env, var_env) id
+ = -- do this pattern match strictly, otherwise we end up holding on to
+ -- stuff in the OccName.
+ case tidyOccName tidy_env (getOccName id) of { (tidy_env', occ') ->
let
-- Give the Id a fresh print-name, *and* rename its type
- -- The SrcLoc isn't important now, though we could extract it from the Id
- name' = mkLocalName (getUnique id) occ' noSrcLoc
- (tidy_env', occ') = tidyOccName tidy_env (getOccName id)
+ -- The SrcLoc isn't important now,
+ -- though we could extract it from the Id
+ --
+ -- All nested Ids now have the same IdInfo, namely vanillaIdInfo,
+ -- which should save some space.
+ -- But note that tidyLetBndr puts some of it back.
ty' = tidyType env (idType id)
- idinfo = idInfo id
- id' = mkVanillaId name' ty'
- `setIdStrictness` strictnessInfo idinfo
- `setIdDemandInfo` demandInfo idinfo
- -- 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.
- --
- -- The exception is strictness and demand info, which
- -- is used to decide whether to use let or case for
- -- function arguments and let bindings
-
+ id' = mkUserLocal occ' (idUnique id) ty' noSrcLoc
+ `setIdInfo` vanillaIdInfo
var_env' = extendVarEnv var_env id id'
in
- ((tidy_env', var_env'), id')
+ ((tidy_env', var_env'), id')
+ }
+\end{code}
+
+\begin{code}
+m =: k = m `seq` k m
\end{code}
projects / ghc-hetmet.git / blobdiff