#include "HsVersions.h"
-import CmdLineOpts ( DynFlags, DynFlag(..), opt_UsageSPOn, dopt )
+import CmdLineOpts ( DynFlags, DynFlag(..), opt_OmitInterfacePragmas )
import CoreSyn
-import CoreUnfold ( noUnfolding )
+import CoreUnfold ( noUnfolding, mkTopUnfolding, okToUnfoldInHiFile )
+import CoreUtils ( exprArity )
+import CoreFVs ( ruleSomeFreeVars, exprSomeFreeVars )
import CoreLint ( showPass, endPass )
-import UsageSPInf ( doUsageSPInf )
import VarEnv
import VarSet
import Var ( Id, Var )
import Id ( idType, idInfo, idName, isExportedId,
- mkVanillaId, mkId,
- idStrictness, setIdStrictness,
- idDemandInfo, setIdDemandInfo,
+ idCafInfo, mkId, isLocalId, isImplicitId,
+ idFlavour, modifyIdInfo, idArity
)
-import IdInfo ( specInfo, setSpecInfo,
- setUnfoldingInfo, setDemandInfo,
- workerInfo, setWorkerInfo, WorkerInfo(..)
+import IdInfo {- loads of stuff -}
+import Name ( getOccName, nameOccName, globaliseName, setNameOcc,
+ localiseName, mkLocalName, isGlobalName, isDllName
)
-import Demand ( wwLazy )
-import Name ( getOccName, tidyTopName, mkLocalName, isGlobalName )
-import OccName ( initTidyOccEnv, tidyOccName )
+import OccName ( TidyOccEnv, initTidyOccEnv, tidyOccName )
import Type ( tidyTopType, tidyType, tidyTyVar )
-import Module ( Module )
-import UniqSupply ( mkSplitUniqSupply )
-import Unique ( Uniquable(..) )
+import Module ( Module, moduleName )
+import PrimOp ( PrimOp(..), setCCallUnique )
+import HscTypes ( PersistentCompilerState( pcs_PRS ),
+ PersistentRenamerState( prsOrig ),
+ NameSupply( nsNames ), OrigNameCache
+ )
+import UniqSupply
+import DataCon ( DataCon, dataConName )
+import Literal ( isLitLitLit )
+import FiniteMap ( lookupFM, addToFM )
+import Maybes ( maybeToBool, orElse )
import ErrUtils ( showPass )
+import PprCore ( pprIdCoreRule )
import SrcLoc ( noSrcLoc )
+import UniqFM ( mapUFM )
+import Outputable
+import FastTypes
+import List ( partition )
import Util ( mapAccumL )
\end{code}
%************************************************************************
-%* *
-\subsection{Tidying core}
-%* *
+%* *
+\subsection{What goes on}
+%* *
%************************************************************************
-Several tasks are done by @tidyCorePgm@
-
-1. If @opt_UsageSPOn@ then compute usage information (which is
- needed by Core2Stg). ** NOTE _scc_ HERE **
- Do this first, because it may introduce new binders.
-
-2. Make certain top-level bindings into Globals. The point is that
- Global things get externally-visible labels at code generation
- time
-
+[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
+
+ - Clone all local Ids. This means that Tidy Core has the property
+ that all Ids are unique, rather than the weaker guarantee of
+ no clashes which the simplifier provides.
+
+ - Give each dynamic CCall occurrence a fresh unique; this is
+ rather like the cloning step above.
+
+ - Give the Id its UTTERLY 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
+
+ * its arity, computed from the number of visible lambdas
+
+ * its CAF info, computed from what is free in its RHS
-3. 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.]
+
+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 ([CoreBind], [IdCoreRule])
-tidyCorePgm dflags module_name binds_in orphans_in
- = do
- us <- mkSplitUniqSupply 'u'
+ -> 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
+
+ ; us <- mkSplitUniqSupply 't' -- for "tidy"
- showPass dflags "Tidy Core"
+ ; let ((us1, orig_env', occ_env, subst_env), binds_out)
+ = mapAccumL (tidyTopBind mod ext_ids)
+ (init_tidy_env us) binds_in
- binds_in1 <- if opt_UsageSPOn
- then _scc_ "CoreUsageSPInf"
- doUsageSPInf dflags us binds_in
- else return binds_in
+ ; let (orphans_out, _)
+ = initUs us1 (tidyIdRules (occ_env,subst_env) orphans_in)
- let (tidy_env1, binds_out) = mapAccumL (tidyBind (Just module_name))
- init_tidy_env binds_in1
- orphans_out = tidyIdRules tidy_env1 orphans_in
+ ; let prs' = prs { prsOrig = orig { nsNames = orig_env' } }
+ pcs' = pcs { pcs_PRS = prs' }
- endPass dflags "Tidy Core" (dopt Opt_D_dump_simpl dflags ||
- dopt Opt_D_verbose_core2core dflags)
- binds_out
+ ; endPass dflags "Tidy Core" Opt_D_dump_simpl binds_out
- return (binds_out, orphans_out)
+ ; return (pcs', binds_out, orphans_out)
+ }
where
-- We also make sure to avoid any exported binders. Consider
-- f{-u1-} = 1 -- Local 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.
- init_tidy_env = (initTidyOccEnv avoids, emptyVarEnv)
- avoids = [getOccName bndr | bndr <- bindersOfBinds binds_in,
+ prs = pcs_PRS pcs
+ orig = prsOrig prs
+ orig_env = nsNames orig
+
+ init_tidy_env us = (us, orig_env, initTidyOccEnv avoids, emptyVarEnv)
+ avoids = [getOccName bndr | bndr <- bindersOfBinds binds_in,
isGlobalName (idName bndr)]
+\end{code}
-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') = tidy_bndr maybe_mod env' env bndr
- rhs' = tidyExpr env' rhs
- -- We use env' when tidying the RHS even though it's not
- -- strictly necessary; it makes the code pretty hard to read
- -- if we don't!
- in
- (env', NonRec bndr' rhs')
-
-tidyBind maybe_mod env (Rec pairs)
- = let
- -- 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 (tidy_bndr maybe_mod env') env bndrs
- rhss' = map (tidyExpr env') rhss
- in
- (env', Rec (zip bndrs' rhss'))
-
-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 Nothing 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
-tidyNote env (Coerce t1 t2) = Coerce (tidyType env t1) (tidyType env t2)
+%************************************************************************
+%* *
+\subsection{Step 1: finding externals}
+%* *
+%************************************************************************
-tidyNote env note = note
+\begin{code}
+findExternalSet :: [CoreBind] -> [IdCoreRule]
+ -> IdEnv Bool -- True <=> show unfolding
+ -- Step 1 from the notes above
+findExternalSet binds orphan_rules
+ = pprTrace "fes" (vcat (map pprIdCoreRule orphan_rules) $$ ppr (varSetElems orphan_rule_ids)) $
+ 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}
-tidyVarOcc (_, var_env) v = case lookupVarEnv var_env v of
- Just v' -> v'
- Nothing -> v
+
+%************************************************************************
+%* *
+\subsection{Step 2: top-level tidying}
+%* *
+%************************************************************************
+
+
+\begin{code}
+type TopTidyEnv = (UniqSupply, OrigNameCache, 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
+--
+-- * uniqsuppy: so we can clone any Ids with non-preordained names.
+--
\end{code}
+
\begin{code}
-tidy_bndr (Just mod) env_idinfo env var = tidyTopId mod env env_idinfo var
-tidy_bndr Nothing env_idinfo env var = tidyBndr env var
+tidyTopBind :: Module
+ -> IdEnv Bool -- Domain = Ids that should be external
+ -- True <=> their unfolding is external too
+ -> TopTidyEnv -> CoreBind
+ -> (TopTidyEnv, CoreBind)
+
+tidyTopBind mod ext_ids env (NonRec bndr rhs)
+ = ((us2,orig,occ,subst) , NonRec bndr' rhs')
+ where
+ ((us1,orig,occ,subst), bndr')
+ = tidyTopBinder mod ext_ids tidy_env rhs' caf_info env bndr
+ tidy_env = (occ,subst)
+ caf_info = hasCafRefs (const True) rhs'
+ (rhs',us2) = initUs us1 (tidyExpr tidy_env rhs)
+
+tidyTopBind mod ext_ids env (Rec prs)
+ = (final_env, Rec prs')
+ where
+ (final_env@(_,_,occ,subst), prs') = mapAccumL do_one env prs
+ final_tidy_env = (occ,subst)
+
+ do_one env (bndr,rhs)
+ = ((us',orig,occ,subst), (bndr',rhs'))
+ where
+ ((us,orig,occ,subst), bndr')
+ = tidyTopBinder mod ext_ids final_tidy_env rhs' caf_info env bndr
+ (rhs', us') = initUs us (tidyExpr final_tidy_env rhs)
+
+ -- the CafInfo for a recursive group says whether *any* rhs in
+ -- the group may refer indirectly to a CAF (because then, they all do).
+ (bndrs, rhss) = unzip prs'
+ caf_info = hasCafRefss pred rhss
+ pred v = v `notElem` bndrs
+
+
+tidyTopBinder :: Module -> IdEnv Bool
+ -> TidyEnv -> CoreExpr -> CafInfo
+ -- The TidyEnv is used to tidy the IdInfo
+ -- The expr is the already-tided RHS
+ -- Both are knot-tied: don't look at them!
+ -> TopTidyEnv -> Id -> (TopTidyEnv, Id)
+
+tidyTopBinder mod ext_ids tidy_env rhs caf_info
+ env@(us, orig_env2, occ_env2, subst_env2) id
+
+ | isImplicitId 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
+
+ = ((us_r, orig_env', occ_env', subst_env'), id')
+ where
+ (us_l, us_r) = splitUniqSupply us
+
+ (orig_env', occ_env', name') = tidyTopName mod orig_env2 occ_env2
+ is_external
+ (idName id)
+ ty' = tidyTopType (idType id)
+ idinfo' = tidyIdInfo us_l tidy_env
+ is_external unfold_info arity_info caf_info id
+
+ id' = mkId name' ty' idinfo'
+ subst_env' = extendVarEnv subst_env2 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
+
+ arity_info = exprArity rhs
+
+
+tidyIdInfo us tidy_env is_external unfold_info arity_info caf_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 caf_info
+ `setStrictnessInfo` strictnessInfo core_idinfo
+ `setArityInfo` ArityExactly arity_info
+ -- Keep strictness, arity and CAF info; it's used by the code generator
+
+ | otherwise
+ = let (rules', _) = initUs us (tidyRules tidy_env (specInfo core_idinfo))
+ in
+ mkIdInfo new_flavour caf_info
+ `setCprInfo` cprInfo core_idinfo
+ `setStrictnessInfo` strictnessInfo core_idinfo
+ `setInlinePragInfo` inlinePragInfo core_idinfo
+ `setUnfoldingInfo` unfold_info
+ `setWorkerInfo` tidyWorker tidy_env arity_info (workerInfo core_idinfo)
+ `setSpecInfo` rules'
+ `setArityInfo` ArityExactly arity_info
+ -- this is the final IdInfo, it must agree with the
+ -- code finally generated (i.e. NO more transformations
+ -- after this!).
+ where
+ 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
+ ConstantId -> ConstantId -- e.g. Default methods
+ DictFunId -> DictFunId
+ flavour -> pprTrace "tidyIdInfo" (ppr id <+> ppFlavourInfo flavour)
+ flavour
+
+
+-- This is where we set names to local/global based on whether they really are
+-- externally visible (see comment at the top of this module). If the name
+-- was previously local, we have to give it a unique occurrence name if
+-- we intend to globalise it.
+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')
+ -- Even local, internal names must get a unique occurrence, because
+ -- if we do -split-objs we globalise the name later, n the code generator
+
+ | global && external = (orig_env, occ_env, name)
+ -- Global names are assumed to have been allocated by the renamer,
+ -- so they already have the "right" unique
+
+ | local && external = case lookupFM orig_env key of
+ Just orig -> (orig_env, occ_env', orig)
+ Nothing -> (addToFM orig_env key global_name, occ_env', global_name)
+ -- 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
+
+ where
+ (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
+
+------------ Worker --------------
+-- We only treat a function as having a worker if
+-- the exported arity (which is now the number of visible lambdas)
+-- is the same as the arity at the moment of the w/w split
+-- If so, we can safely omit the unfolding inside the wrapper, and
+-- instead re-generate it from the type/arity/strictness info
+-- But if the arity has changed, we just take the simple path and
+-- put the unfolding into the interface file, forgetting the fact
+-- that it's a wrapper.
+--
+-- How can this happen? Sometimes we get
+-- f = coerce t (\x y -> $wf x y)
+-- at the moment of w/w split; but the eta reducer turns it into
+-- f = coerce t $wf
+-- which is perfectly fine except that the exposed arity so far as
+-- the code generator is concerned (zero) differs from the arity
+-- when we did the split (2).
+--
+-- All this arises because we use 'arity' to mean "exactly how many
+-- top level lambdas are there" in interface files; but during the
+-- compilation of this module it means "how many things can I apply
+-- this to".
+tidyWorker tidy_env real_arity (HasWorker work_id wrap_arity)
+ | real_arity == wrap_arity
+ = HasWorker (tidyVarOcc tidy_env work_id) wrap_arity
+tidyWorker tidy_env real_arity other
+ = NoWorker
+
+------------ Rules --------------
+tidyIdRules :: TidyEnv -> [IdCoreRule] -> UniqSM [IdCoreRule]
+tidyIdRules env [] = returnUs []
+tidyIdRules env ((fn,rule) : rules)
+ = tidyRule env rule `thenUs` \ rule ->
+ tidyIdRules env rules `thenUs` \ rules ->
+ returnUs ((tidyVarOcc env fn, rule) : rules)
+
+tidyRules :: TidyEnv -> CoreRules -> UniqSM CoreRules
+tidyRules env (Rules rules fvs)
+ = mapUs (tidyRule env) rules `thenUs` \ rules ->
+ returnUs (Rules rules (foldVarSet tidy_set_elem emptyVarSet fvs))
+ where
+ tidy_set_elem var new_set = extendVarSet new_set (tidyVarOcc env var)
+
+tidyRule :: TidyEnv -> CoreRule -> UniqSM CoreRule
+tidyRule env rule@(BuiltinRule _) = returnUs rule
+tidyRule env (Rule name vars tpl_args rhs)
+ = tidyBndrs env vars `thenUs` \ (env', vars) ->
+ mapUs (tidyExpr env') tpl_args `thenUs` \ tpl_args ->
+ tidyExpr env' rhs `thenUs` \ rhs ->
+ returnUs (Rule name vars tpl_args rhs)
\end{code}
+%************************************************************************
+%* *
+\subsection{Step 2: inner tidying
+%* *
+%************************************************************************
+
+\begin{code}
+tidyBind :: TidyEnv
+ -> CoreBind
+ -> UniqSM (TidyEnv, CoreBind)
+tidyBind env (NonRec bndr rhs)
+ = tidyBndrWithRhs env (bndr,rhs) `thenUs` \ (env', bndr') ->
+ tidyExpr env' rhs `thenUs` \ rhs' ->
+ returnUs (env', NonRec bndr' rhs')
+
+tidyBind env (Rec prs)
+ = mapAccumLUs tidyBndrWithRhs env prs `thenUs` \ (env', bndrs') ->
+ mapUs (tidyExpr env') (map snd prs) `thenUs` \ rhss' ->
+ returnUs (env', Rec (zip bndrs' rhss'))
+
+tidyExpr env (Var v)
+ = fiddleCCall v `thenUs` \ v ->
+ returnUs (Var (tidyVarOcc env v))
+
+tidyExpr env (Type ty) = returnUs (Type (tidyType env ty))
+tidyExpr env (Lit lit) = returnUs (Lit lit)
+
+tidyExpr env (App f a)
+ = tidyExpr env f `thenUs` \ f ->
+ tidyExpr env a `thenUs` \ a ->
+ returnUs (App f a)
+
+tidyExpr env (Note n e)
+ = tidyExpr env e `thenUs` \ e ->
+ returnUs (Note (tidyNote env n) e)
+
+tidyExpr env (Let b e)
+ = tidyBind env b `thenUs` \ (env', b') ->
+ tidyExpr env' e `thenUs` \ e ->
+ returnUs (Let b' e)
+
+tidyExpr env (Case e b alts)
+ = tidyExpr env e `thenUs` \ e ->
+ tidyBndr env b `thenUs` \ (env', b) ->
+ mapUs (tidyAlt env') alts `thenUs` \ alts ->
+ returnUs (Case e b alts)
+
+tidyExpr env (Lam b e)
+ = tidyBndr env b `thenUs` \ (env', b) ->
+ tidyExpr env' e `thenUs` \ e ->
+ returnUs (Lam b e)
+
+
+tidyAlt env (con, vs, rhs)
+ = tidyBndrs env vs `thenUs` \ (env', vs) ->
+ tidyExpr env' rhs `thenUs` \ rhs ->
+ returnUs (con, vs, rhs)
+
+tidyNote env (Coerce t1 t2) = Coerce (tidyType env t1) (tidyType env t2)
+tidyNote env note = note
+\end{code}
%************************************************************************
%* *
-\subsection{Tidying up a binder}
+\subsection{Tidying up non-top-level binders}
%* *
%************************************************************************
\begin{code}
-tidyBndr :: TidyEnv -> Var -> (TidyEnv, Var)
-tidyBndr env var | isTyVar var = tidyTyVar env var
- | otherwise = tidyId env var
+tidyVarOcc (_, var_env) v = case lookupVarEnv var_env v of
+ Just v' -> v'
+ Nothing -> v
-tidyBndrs :: TidyEnv -> [Var] -> (TidyEnv, [Var])
-tidyBndrs env vars = mapAccumL tidyBndr env vars
+-- tidyBndr is used for lambda and case binders
+tidyBndr :: TidyEnv -> Var -> UniqSM (TidyEnv, Var)
+tidyBndr env var
+ | isTyVar var = returnUs (tidyTyVar env var)
+ | otherwise = tidyId env var vanillaIdInfo
+
+tidyBndrs :: TidyEnv -> [Var] -> UniqSM (TidyEnv, [Var])
+tidyBndrs env vars = mapAccumLUs tidyBndr env vars
+
+-- tidyBndrWithRhs is used for let binders
+tidyBndrWithRhs :: TidyEnv -> (Var, CoreExpr) -> UniqSM (TidyEnv, Var)
+tidyBndrWithRhs env (id,rhs)
+ = tidyId env id idinfo
+ where
+ idinfo = vanillaIdInfo `setArityInfo` ArityExactly (exprArity rhs)
+ -- 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.
-tidyId :: TidyEnv -> Id -> (TidyEnv, Id)
-tidyId env@(tidy_env, var_env) id
+tidyId :: TidyEnv -> Id -> IdInfo -> UniqSM (TidyEnv, Id)
+tidyId env@(tidy_env, var_env) id idinfo
= -- Non-top-level variables
+ getUniqueUs `thenUs` \ uniq ->
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
+ -- The SrcLoc isn't important now,
+ -- though we could extract it from the Id
+ name' = mkLocalName uniq occ' noSrcLoc
(tidy_env', occ') = tidyOccName tidy_env (getOccName id)
- ty' = tidyType env (idType id)
- id' = mkVanillaId name' ty'
- `setIdStrictness` idStrictness id
- `setIdDemandInfo` idDemandInfo id
- -- 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
-
+ ty' = tidyType (tidy_env,var_env) (idType id)
+ id' = mkId name' ty' idinfo
var_env' = extendVarEnv var_env id id'
in
- ((tidy_env', var_env'), id')
-
-tidyTopId :: Module -> TidyEnv -> TidyEnv -> Id -> (TidyEnv, Id)
- -- 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
-tidyTopId mod env@(tidy_env, var_env) env_idinfo id
- = -- Top level variables
- let
- (tidy_env', name') = tidyTopName mod tidy_env (isExportedId id) (idName id)
- ty' = tidyTopType (idType id)
- idinfo' = tidyIdInfo env_idinfo (idInfo id)
- id' = mkId name' ty' idinfo'
- var_env' = extendVarEnv var_env id id'
- in
- ((tidy_env', var_env'), id')
+ returnUs ((tidy_env', var_env'), id')
+
+
+fiddleCCall id
+ = case idFlavour id of
+ PrimOpId (CCallOp ccall) ->
+ -- Make a guaranteed unique name for a dynamic ccall.
+ getUniqueUs `thenUs` \ uniq ->
+ returnUs (modifyIdInfo (`setFlavourInfo`
+ PrimOpId (CCallOp (setCCallUnique ccall uniq))) id)
+ other_flavour ->
+ returnUs id
\end{code}
-\begin{code}
--- tidyIdInfo does these things:
--- a) tidy the specialisation info and worker info (if any)
--- b) zap the unfolding and demand info
--- The latter two are to avoid space leaks
-
-tidyIdInfo env info
- = info5
- where
- rules = specInfo info
-
- info2 | isEmptyCoreRules rules = info
- | otherwise = info `setSpecInfo` tidyRules env rules
-
- info3 = info2 `setUnfoldingInfo` noUnfolding
- info4 = info3 `setDemandInfo` wwLazy
+%************************************************************************
+%* *
+\subsection{Figuring out CafInfo for an expression}
+%* *
+%************************************************************************
- info5 = case workerInfo info of
- NoWorker -> info4
- HasWorker w a -> info4 `setWorkerInfo` HasWorker (tidyVarOcc env w) a
+hasCafRefs decides whether a top-level closure can point into the dynamic heap.
+We mark such things as `MayHaveCafRefs' because this information is
+used to decide whether a particular closure needs to be referenced
+in an SRT or not.
-tidyIdRules :: TidyEnv -> [IdCoreRule] -> [IdCoreRule]
-tidyIdRules env rules
- = [ (tidyVarOcc env fn, tidyRule env rule) | (fn,rule) <- rules ]
+There are two reasons for setting MayHaveCafRefs:
+ a) The RHS is a CAF: a top-level updatable thunk.
+ b) The RHS refers to something that MayHaveCafRefs
-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)
+Possible improvement: In an effort to keep the number of CAFs (and
+hence the size of the SRTs) down, we could also look at the expression and
+decide whether it requires a small bounded amount of heap, so we can ignore
+it as a CAF. In these cases however, we would need to use an additional
+CAF list to keep track of non-collectable CAFs.
-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))
+\begin{code}
+hasCafRefs :: (Id -> Bool) -> CoreExpr -> CafInfo
+-- Only called for the RHS of top-level lets
+hasCafRefss :: (Id -> Bool) -> [CoreExpr] -> CafInfo
+ -- predicate returns True for a given Id if we look at this Id when
+ -- calculating the result. Used to *avoid* looking at the CafInfo
+ -- field for an Id that is part of the current recursive group.
+
+hasCafRefs p expr = if isCAF expr || isFastTrue (cafRefs p expr)
+ then MayHaveCafRefs
+ else NoCafRefs
+
+ -- used for recursive groups. The whole group is set to
+ -- "MayHaveCafRefs" if at least one of the group is a CAF or
+ -- refers to any CAFs.
+hasCafRefss p exprs = if any isCAF exprs || isFastTrue (cafRefss p exprs)
+ then MayHaveCafRefs
+ else NoCafRefs
+
+cafRefs p (Var id)
+ | p id
+ = case idCafInfo id of
+ NoCafRefs -> fastBool False
+ MayHaveCafRefs -> fastBool True
+ | otherwise
+ = fastBool False
+
+cafRefs p (Lit l) = fastBool False
+cafRefs p (App f a) = cafRefs p f `fastOr` cafRefs p a
+cafRefs p (Lam x e) = cafRefs p e
+cafRefs p (Let b e) = cafRefss p (rhssOfBind b) `fastOr` cafRefs p e
+cafRefs p (Case e bndr alts) = cafRefs p e `fastOr` cafRefss p (rhssOfAlts alts)
+cafRefs p (Note n e) = cafRefs p e
+cafRefs p (Type t) = fastBool False
+
+cafRefss p [] = fastBool False
+cafRefss p (e:es) = cafRefs p e `fastOr` cafRefss p es
+
+
+isCAF :: CoreExpr -> Bool
+-- Only called for the RHS of top-level lets
+isCAF e = not (rhsIsNonUpd e)
+ {- ToDo: check type for onceness, i.e. non-updatable thunks? -}
+
+rhsIsNonUpd :: CoreExpr -> Bool
+ -- True => Value-lambda, constructor, PAP
+ -- This is a bit like CoreUtils.exprIsValue, with the following differences:
+ -- a) scc "foo" (\x -> ...) is updatable (so we catch the right SCC)
+ --
+ -- b) (C x xs), where C is a contructors is updatable if the application is
+ -- dynamic: see isDynConApp
+ --
+ -- c) don't look through unfolding of f in (f x). I'm suspicious of this one
+
+rhsIsNonUpd (Lam b e) = isId b || rhsIsNonUpd e
+rhsIsNonUpd (Note (SCC _) e) = False
+rhsIsNonUpd (Note _ e) = rhsIsNonUpd e
+rhsIsNonUpd other_expr
+ = go other_expr 0 []
where
- (env', vars') = tidyBndrs env vars
+ go (Var f) n_args args = idAppIsNonUpd f n_args args
+
+ go (App f a) n_args args
+ | isTypeArg a = go f n_args args
+ | otherwise = go f (n_args + 1) (a:args)
+
+ go (Note (SCC _) f) n_args args = False
+ go (Note _ f) n_args args = go f n_args args
+
+ go other n_args args = False
+
+idAppIsNonUpd :: Id -> Int -> [CoreExpr] -> Bool
+idAppIsNonUpd id n_val_args args
+ = case idFlavour id of
+ DataConId con | not (isDynConApp con args) -> True
+ other -> n_val_args < idArity id
+
+isDynConApp :: DataCon -> [CoreExpr] -> Bool
+isDynConApp con args = isDllName (dataConName con) || any isDynArg args
+-- Top-level constructor applications can usually be allocated
+-- statically, but they can't if
+-- a) the constructor, or any of the arguments, come from another DLL
+-- b) any of the arguments are LitLits
+-- (because we can't refer to static labels in other DLLs).
+-- If this happens we simply make the RHS into an updatable thunk,
+-- and 'exectute' it rather than allocating it statically.
+-- All this should match the decision in (see CoreToStg.coreToStgRhs)
+
+
+isDynArg :: CoreExpr -> Bool
+isDynArg (Var v) = isDllName (idName v)
+isDynArg (Note _ e) = isDynArg e
+isDynArg (Lit lit) = isLitLitLit lit
+isDynArg (App e _) = isDynArg e -- must be a type app
+isDynArg (Lam _ e) = isDynArg e -- must be a type lam
\end{code}
projects / ghc-hetmet.git / blobdiff