\begin{code}
module CoreTidy (
- tidyCorePgm, tidyExpr, tidyCoreExpr,
+ tidyCorePgm, tidyExpr, tidyCoreExpr, tidyIdRules,
tidyBndr, tidyBndrs
) where
import CmdLineOpts ( DynFlags, DynFlag(..), opt_OmitInterfacePragmas )
import CoreSyn
import CoreUnfold ( noUnfolding, mkTopUnfolding, okToUnfoldInHiFile )
-import CoreUtils ( exprArity )
-import CoreFVs ( ruleSomeFreeVars, exprSomeFreeVars, ruleSomeLhsFreeVars )
+import CoreFVs ( ruleLhsFreeIds, ruleRhsFreeVars, exprSomeFreeVars )
+import PprCore ( pprIdRules )
import CoreLint ( showPass, endPass )
+import CoreUtils ( exprArity )
import VarEnv
import VarSet
-import Var ( Id, Var, varName, globalIdDetails, setGlobalIdDetails )
-import Id ( idType, idInfo, idName, isExportedId, idSpecialisation,
- idCafInfo, mkVanillaGlobal, isLocalId, isImplicitId,
- modifyIdInfo, idArity, hasNoBinding, mkLocalIdWithInfo
+import Var ( Id, Var )
+import Id ( idType, idInfo, idName, idCoreRules,
+ isExportedId, idUnique, mkVanillaGlobal, isLocalId,
+ isImplicitId, mkUserLocal, setIdInfo
)
import IdInfo {- loads of stuff -}
-import Name ( getOccName, nameOccName, globaliseName, setNameOcc,
- localiseName, mkLocalName, isGlobalName, isDllName, isLocalName
+import NewDemand ( isBottomingSig, topSig )
+import BasicTypes ( isNeverActive )
+import Name ( getOccName, nameOccName, mkInternalName, mkExternalName,
+ localiseName, isExternalName, nameSrcLoc
)
import NameEnv ( filterNameEnv )
import OccName ( TidyOccEnv, initTidyOccEnv, tidyOccName )
-import Type ( tidyTopType, tidyType, tidyTyVar )
+import Type ( tidyTopType, tidyType, tidyTyVarBndr )
import Module ( Module, moduleName )
-import PrimOp ( PrimOp(..), setCCallUnique )
import HscTypes ( PersistentCompilerState( pcs_PRS ),
PersistentRenamerState( prsOrig ),
- NameSupply( nsNames ), OrigNameCache,
- TypeEnv, extendTypeEnvList,
- DFunId, ModDetails(..), TyThing(..)
+ NameSupply( nsNames, nsUniqs ),
+ TypeEnv, extendTypeEnvList, typeEnvIds,
+ ModDetails(..), TyThing(..)
)
-import UniqSupply
-import DataCon ( DataCon, dataConName )
-import Literal ( isLitLitLit )
import FiniteMap ( lookupFM, addToFM )
-import Maybes ( maybeToBool, orElse )
-import ErrUtils ( showPass )
-import PprCore ( pprIdCoreRule )
+import Maybes ( orElse )
+import ErrUtils ( showPass, dumpIfSet_core )
import SrcLoc ( noSrcLoc )
import UniqFM ( mapUFM )
-import Outputable
-import FastTypes
+import UniqSupply ( splitUniqSupply, uniqFromSupply )
import List ( partition )
import Util ( mapAccumL )
+import Maybe ( isJust )
+import Outputable
\end{code}
Step 2: Tidy the program
~~~~~~~~~~~~~~~~~~~~~~~~
-Next we traverse the bindings top to bottom. For each top-level
+Next we traverse the bindings top to bottom. For each *top-level*
binder
- - Make all external Ids have Global names and vice versa
+ 1. Make it into a GlobalId
+
+ 2. Give it a system-wide Unique.
+ [Even non-exported things need system-wide Uniques because the
+ byte-code generator builds a single Name->BCO symbol table.]
+
+ We use the NameSupply kept in the PersistentRenamerState as the
+ source of such system-wide uniques.
+
+ For external Ids, use the original-name cache in the NameSupply
+ to ensure that the unique assigned is the same as the Id had
+ in any previous compilation run.
+
+ 3. If it's an external Id, make it have a global Name, otherwise
+ make it have a local Name.
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
+ 4. 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,
+ 5. Give it its UTTERLY FINAL IdInfo; in ptic,
* Its IdDetails becomes VanillaGlobal, reflecting the fact that
from now on we regard it as a global, not local, Id
\begin{code}
tidyCorePgm :: DynFlags -> Module
-> PersistentCompilerState
- -> TypeEnv -> [DFunId]
- -> [CoreBind] -> [IdCoreRule]
- -> IO (PersistentCompilerState, [CoreBind], ModDetails)
-
-tidyCorePgm dflags mod pcs env_tc insts_tc binds_in orphans_in
+ -> CgInfoEnv -- Information from the back end,
+ -- to be splatted into the IdInfo
+ -> ModDetails
+ -> IO (PersistentCompilerState, ModDetails)
+
+tidyCorePgm dflags mod pcs cg_info_env
+ (ModDetails { md_types = env_tc, md_insts = insts_tc,
+ md_binds = binds_in, md_rules = orphans_in })
= do { showPass dflags "Tidy Core"
- ; let ext_ids = findExternalSet binds_in orphans_in
-
- ; us <- mkSplitUniqSupply 't' -- for "tidy"
-
- ; let ((us1, orig_env', occ_env, subst_env), tidy_binds)
- = mapAccumL (tidyTopBind mod ext_ids)
- (init_tidy_env us) binds_in
+ ; let ext_ids = findExternalSet binds_in orphans_in
+ ; let ext_rules = findExternalRules binds_in orphans_in ext_ids
+ -- findExternalRules filters ext_rules to avoid binders that
+ -- aren't externally visible; but the externally-visible binders
+ -- are computed (by findExternalSet) assuming that all orphan
+ -- rules are exported. So in fact we may export more than we
+ -- need. (It's a sort of mutual recursion.)
- ; let (orphans_out, _)
- = initUs us1 (tidyIdRules (occ_env,subst_env) orphans_in)
-
- ; let prs' = prs { prsOrig = orig { nsNames = orig_env' } }
+ -- 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.
+ ; let prs = pcs_PRS pcs
+ orig_ns = prsOrig prs
+
+ init_tidy_env = (orig_ns, initTidyOccEnv avoids, emptyVarEnv)
+ avoids = [getOccName name | bndr <- typeEnvIds env_tc,
+ let name = idName bndr,
+ isExternalName name]
+ -- In computing our "avoids" list, we must include
+ -- all implicit Ids
+ -- all things with global names (assigned once and for
+ -- all by the renamer)
+ -- since their names are "taken".
+ -- The type environment is a convenient source of such things.
+
+ ; let ((orig_ns', occ_env, subst_env), tidy_binds)
+ = mapAccumL (tidyTopBind mod ext_ids cg_info_env)
+ init_tidy_env binds_in
+
+ ; let tidy_rules = tidyIdCoreRules (occ_env,subst_env) ext_rules
+
+ ; let prs' = prs { prsOrig = orig_ns' }
pcs' = pcs { pcs_PRS = prs' }
- ; let final_ids = [ id | bind <- tidy_binds
+ ; let final_ids = [ id
+ | bind <- tidy_binds
, id <- bindersOf bind
- , isGlobalName (idName id)]
+ , isExternalName (idName id)]
-- Dfuns are local Ids that might have
-- changed their unique during tidying
pprPanic "lookup_dfun_id" (ppr id)
- ; let final_rules = mkFinalRules orphans_out final_ids
- final_type_env = mkFinalTypeEnv env_tc final_ids
- final_dfun_ids = map lookup_dfun_id insts_tc
+ ; let tidy_type_env = mkFinalTypeEnv env_tc final_ids
+ tidy_dfun_ids = map lookup_dfun_id insts_tc
- ; let new_details = ModDetails { md_types = final_type_env,
- md_rules = final_rules,
- md_insts = final_dfun_ids }
+ ; let tidy_details = ModDetails { md_types = tidy_type_env,
+ md_rules = tidy_rules,
+ md_insts = tidy_dfun_ids,
+ md_binds = tidy_binds }
; endPass dflags "Tidy Core" Opt_D_dump_simpl tidy_binds
+ ; dumpIfSet_core dflags Opt_D_dump_simpl
+ "Tidy Core Rules"
+ (pprIdRules tidy_rules)
- ; return (pcs', tidy_binds, new_details)
+ ; return (pcs', tidy_details)
}
- 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 = nsNames orig
-
- init_tidy_env us = (us, orig_env, initTidyOccEnv avoids, emptyVarEnv)
- avoids = [getOccName bndr | bndr <- bindersOfBinds binds_in,
- isGlobalName (idName bndr)]
-
tidyCoreExpr :: CoreExpr -> IO CoreExpr
-tidyCoreExpr expr
- = do { us <- mkSplitUniqSupply 't' -- for "tidy"
- ; let (expr',_) = initUs us (tidyExpr emptyTidyEnv expr)
- ; return expr'
- }
+tidyCoreExpr expr = return (tidyExpr emptyTidyEnv expr)
\end{code}
-- in interface files, because they are needed by importing modules when
-- using the compilation manager
- -- We keep constructor workers, because they won't appear
+ -- We keep implicit Ids, because they won't appear
-- in the bindings from which final_ids are derived!
- keep_it (AnId id) = hasNoBinding id -- Remove all Ids except constructor workers
+ keep_it (AnId id) = isImplicitId id -- Remove all Ids except implicit ones
keep_it other = True -- Keep all TyCons and Classes
\end{code}
\begin{code}
-mkFinalRules :: [IdCoreRule] -- Orphan rules
- -> [Id] -- Ids that are exported, so we need their rules
- -> [IdCoreRule]
+findExternalRules :: [CoreBind]
+ -> [IdCoreRule] -- Orphan rules
+ -> IdEnv a -- Ids that are exported, so we need their rules
+ -> [IdCoreRule]
-- The complete rules are gotten by combining
-- a) the orphan rules
-- b) rules embedded in the top-level Ids
-mkFinalRules orphan_rules emitted
+findExternalRules binds orphan_rules ext_ids
| opt_OmitInterfacePragmas = []
| otherwise
- = orphan_rules ++ local_rules
+ = filter needed_rule (orphan_rules ++ local_rules)
where
- local_rules = [ (fn, rule)
- | fn <- emitted,
- rule <- rulesRules (idSpecialisation fn),
- not (isBuiltinRule rule),
- -- We can't print builtin rules in interface files
- -- Since they are built in, an importing module
- -- will have access to them anyway
-
- -- Sept 00: I've disabled this test. It doesn't stop many, if any, rules
- -- from coming out, and to make it work properly we need to add ????
- -- (put it back in for now)
- isEmptyVarSet (ruleSomeLhsFreeVars (isLocalName . varName) rule)
- -- Spit out a rule only if none of its LHS free vars are
- -- LocalName things i.e. things that aren't visible to importing modules
- -- This is a good reason not to do it when we emit the Id itself
+ local_rules = [ rule
+ | id <- bindersOfBinds binds,
+ id `elemVarEnv` ext_ids,
+ rule <- idCoreRules id
]
+ needed_rule (id, rule)
+ = not (isBuiltinRule rule)
+ -- We can't print builtin rules in interface files
+ -- Since they are built in, an importing module
+ -- will have access to them anyway
+
+ && not (any internal_id (varSetElems (ruleLhsFreeIds rule)))
+ -- Don't export a rule whose LHS mentions an Id that
+ -- is completely internal (i.e. not visible to an
+ -- importing module)
+
+ internal_id id = isLocalId id && not (id `elemVarEnv` ext_ids)
\end{code}
-
%************************************************************************
%* *
\subsection{Step 1: finding externals}
\begin{code}
findExternalSet :: [CoreBind] -> [IdCoreRule]
- -> IdEnv Bool -- True <=> show unfolding
+ -> IdEnv Bool -- In domain => external
+ -- Range = 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 isLocalId rule
+ orphan_rule_ids = unionVarSets [ ruleRhsFreeVars rule
| (_, rule) <- orphan_rules]
init_needed :: IdEnv Bool
init_needed = mapUFM (\_ -> False) orphan_rule_ids
spec_ids
idinfo = idInfo id
- dont_inline = isNeverInlinePrag (inlinePragInfo idinfo)
+ dont_inline = isNeverActive (inlinePragInfo idinfo)
loop_breaker = isLoopBreaker (occInfo idinfo)
- bottoming_fn = isBottomingStrictness (strictnessInfo idinfo)
+ bottoming_fn = isBottomingSig (newStrictnessInfo idinfo `orElse` topSig)
spec_ids = rulesRhsFreeVars (specInfo idinfo)
worker_info = workerInfo idinfo
\begin{code}
-type TopTidyEnv = (UniqSupply, OrigNameCache, TidyOccEnv, VarEnv Var)
+type TopTidyEnv = (NameSupply, TidyOccEnv, VarEnv Var)
-- TopTidyEnv: when tidying we need to know
--- * orig_env: Any pre-ordained Names. These may have arisen because the
+-- * ns: The NameSupply, containing a unique supply and 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)
-- 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}
tidyTopBind :: Module
-> IdEnv Bool -- Domain = Ids that should be external
-- True <=> their unfolding is external too
+ -> CgInfoEnv
-> TopTidyEnv -> CoreBind
-> (TopTidyEnv, CoreBind)
-tidyTopBind mod ext_ids env (NonRec bndr rhs)
- = ((us2,orig,occ,subst) , NonRec bndr' rhs')
+tidyTopBind mod ext_ids cg_info_env top_tidy_env (NonRec bndr rhs)
+ = ((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)
+ ((orig,occ,subst), bndr')
+ = tidyTopBinder mod ext_ids cg_info_env
+ rec_tidy_env rhs rhs' top_tidy_env bndr
+ rec_tidy_env = (occ,subst)
+ rhs' = tidyExpr rec_tidy_env rhs
-tidyTopBind mod ext_ids env (Rec prs)
+tidyTopBind mod ext_ids cg_info_env top_tidy_env (Rec prs)
= (final_env, Rec prs')
where
- (final_env@(_,_,occ,subst), prs') = mapAccumL do_one env prs
- final_tidy_env = (occ,subst)
+ (final_env@(_,occ,subst), prs') = mapAccumL do_one top_tidy_env prs
+ rec_tidy_env = (occ,subst)
- do_one env (bndr,rhs)
- = ((us',orig,occ,subst), (bndr',rhs'))
+ do_one top_tidy_env (bndr,rhs)
+ = ((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!
+ ((orig,occ,subst), bndr')
+ = tidyTopBinder mod ext_ids cg_info_env
+ rec_tidy_env rhs rhs' top_tidy_env bndr
+
+ rhs' = tidyExpr rec_tidy_env rhs
+
+tidyTopBinder :: Module -> IdEnv Bool -> CgInfoEnv
+ -> TidyEnv -- The TidyEnv is used to tidy the IdInfo
+ -> CoreExpr -- RHS *before* tidying
+ -> CoreExpr -- RHS *after* tidying
+ -- The TidyEnv and the after-tidying RHS are
+ -- both are knot-tied: don't look at them!
-> TopTidyEnv -> Id -> (TopTidyEnv, Id)
+ -- NB: tidyTopBinder doesn't affect the unique supply
-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
+tidyTopBinder mod ext_ids cg_info_env rec_tidy_env rhs tidy_rhs
+ env@(ns2, occ_env2, subst_env2) id
-- This function is the heart of Step 2
- -- The second env is the one to use for the IdInfo
+ -- The rec_tidy_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')
+ = ((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
+ (orig_env', occ_env', name') = tidyTopName mod ns2 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
+ ty' = tidyTopType (idType id)
+ idinfo = tidyTopIdInfo rec_tidy_env is_external
+ (idInfo id) unfold_info arity
+ (lookupCgInfo cg_info_env name')
+
+ id' = mkVanillaGlobal name' ty' idinfo
- id' = mkVanillaGlobal name' ty' idinfo'
subst_env' = extendVarEnv subst_env2 id id'
maybe_external = lookupVarEnv ext_ids id
- is_external = maybeToBool maybe_external
+ is_external = isJust maybe_external
-- Expose an unfolding if ext_ids tells us to
+ -- Remember that ext_ids maps an Id to a Bool:
+ -- True to show the unfolding, False to hide it
show_unfold = maybe_external `orElse` False
- unfold_info | show_unfold = mkTopUnfolding rhs
+ unfold_info | show_unfold = mkTopUnfolding tidy_rhs
| otherwise = noUnfolding
- arity_info = exprArity rhs
+ -- Usually the Id will have an accurate arity on it, because
+ -- the simplifier has just run, but not always.
+ -- One case I found was when the last thing the simplifier
+ -- did was to let-bind a non-atomic argument and then float
+ -- it to the top level. So it seems more robust just to
+ -- fix it here.
+ arity = 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
- = vanillaIdInfo
- `setCafInfo` 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
- vanillaIdInfo
- `setCafInfo` 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!).
+-- tidyTopIdInfo creates the final IdInfo for top-level
+-- binders. There are two delicate pieces:
+--
+-- * Arity. After CoreTidy, this arity must not change any more.
+-- Indeed, CorePrep must eta expand where necessary to make
+-- the manifest arity equal to the claimed arity.
+--
+-- * CAF info, which comes from the CoreToStg pass via a knot.
+-- The CAF info will not be looked at by the downstream stuff:
+-- it *generates* it, and knot-ties it back. It will only be
+-- looked at by (a) MkIface when generating an interface file
+-- (b) In GHCi, importing modules
+-- Nevertheless, we add the info here so that it propagates to all
+-- occurrences of the binders in RHSs, and hence to occurrences in
+-- unfoldings, which are inside Ids imported by GHCi. Ditto RULES.
+--
+-- An alterative would be to do a second pass over the unfoldings
+-- of Ids, and rules, right at the top, but that would be a pain.
+
+tidyTopIdInfo tidy_env is_external idinfo unfold_info arity cg_info
+ | opt_OmitInterfacePragmas || not is_external
+ -- Only basic info if the Id isn't external, or if we don't have -O
+ = basic_info
+
+ | otherwise -- Add extra optimisation info
+ = basic_info
+ `setInlinePragInfo` inlinePragInfo idinfo
+ `setUnfoldingInfo` unfold_info
+ `setWorkerInfo` tidyWorker tidy_env (workerInfo idinfo)
+ -- NB: we throw away the Rules
+ -- They have already been extracted by findExternalRules
+
where
- core_idinfo = idInfo id
+ -- baasic_info is attached to every top-level binder
+ basic_info = vanillaIdInfo
+ `setCgInfo` cg_info
+ `setArityInfo` arity
+ `setAllStrictnessInfo` newStrictnessInfo idinfo
-- 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)
+-- we intend to externalise it.
+tidyTopName mod ns occ_env external name
+ | global && internal = (ns, 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 && external = (ns, occ_env, name)
-- Global names are assumed to have been allocated by the renamer,
-- so they already have the "right" unique
+ -- And it's a system-wide unique too
+
+ | local && internal = (ns_w_local, occ_env', new_local_name)
+ -- Even local, internal names must get a unique occurrence, because
+ -- if we do -split-objs we externalise the name later, in the code generator
+ --
+ -- Similarly, we must make sure it has a system-wide Unique, because
+ -- the byte-code generator builds a system-wide Name->BCO symbol table
- | 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
+ | local && external = case lookupFM ns_names key of
+ Just orig -> (ns, occ_env', orig)
+ Nothing -> (ns_w_global, occ_env', new_external_name)
+ -- If we want to externalise a currently-local name, check
-- whether we have already assigned a unique for it.
- -- If so, use it; if not, extend the table
+ -- If so, use it; if not, extend the table (ns_w_global).
+ -- This is needed when *re*-compiling a module in GHCi; we want to
+ -- use the same name for externally-visible things as we did before.
where
- (occ_env', occ') = tidyOccName occ_env (nameOccName name)
- key = (moduleName mod, occ')
- global_name = globaliseName (setNameOcc name occ') mod
- global = isGlobalName name
+ global = isExternalName name
local = not global
internal = not external
+ (occ_env', occ') = tidyOccName occ_env (nameOccName name)
+ key = (moduleName mod, occ')
+ ns_names = nsNames ns
+ ns_uniqs = nsUniqs ns
+ (us1, us2) = splitUniqSupply ns_uniqs
+ uniq = uniqFromSupply us1
+ loc = nameSrcLoc name
+
+ new_local_name = mkInternalName uniq occ' loc
+ new_external_name = mkExternalName uniq mod occ' loc
+
+ ns_w_local = ns { nsUniqs = us2 }
+ ns_w_global = ns { nsUniqs = us2, nsNames = addToFM ns_names key new_external_name }
+
+
------------ 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
+tidyWorker tidy_env (HasWorker work_id wrap_arity)
= HasWorker (tidyVarOcc tidy_env work_id) wrap_arity
-tidyWorker tidy_env real_arity other
+tidyWorker tidy_env 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)
+tidyIdRules :: Id -> [IdCoreRule]
+tidyIdRules id = tidyIdCoreRules emptyTidyEnv (idCoreRules id)
+
+tidyIdCoreRules :: TidyEnv -> [IdCoreRule] -> [IdCoreRule]
+tidyIdCoreRules env [] = []
+tidyIdCoreRules env ((fn,rule) : rules)
+ = tidyRule env rule =: \ rule ->
+ tidyIdCoreRules env rules =: \ rules ->
+ ((tidyVarOcc env fn, rule) : rules)
+
+tidyRule :: TidyEnv -> CoreRule -> CoreRule
+tidyRule env rule@(BuiltinRule _ _) = rule
+tidyRule env (Rule name act vars tpl_args rhs)
+ = tidyBndrs env vars =: \ (env', vars) ->
+ map (tidyExpr env') tpl_args =: \ tpl_args ->
+ (Rule name act vars tpl_args (tidyExpr env' rhs))
\end{code}
%************************************************************************
\begin{code}
tidyBind :: TidyEnv
-> CoreBind
- -> UniqSM (TidyEnv, CoreBind)
+ -> (TidyEnv, CoreBind)
+
tidyBind env (NonRec bndr rhs)
- = tidyBndrWithRhs env (bndr,rhs) `thenUs` \ (env', bndr') ->
- tidyExpr env' rhs `thenUs` \ rhs' ->
- returnUs (env', NonRec bndr' rhs')
+ = tidyLetBndr env (bndr,rhs) =: \ (env', bndr') ->
+ (env', NonRec bndr' (tidyExpr env' 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))
+ = mapAccumL tidyLetBndr env prs =: \ (env', bndrs') ->
+ map (tidyExpr env') (map snd prs) =: \ rhss' ->
+ (env', Rec (zip bndrs' rhss'))
-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 (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 `thenUs` \ (env', b') ->
- tidyExpr env' e `thenUs` \ e ->
- returnUs (Let b' e)
+ = tidyBind env b =: \ (env', b') ->
+ Let b' (tidyExpr env' 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)
+ = tidyBndr env b =: \ (env', b) ->
+ Case (tidyExpr env e) b (map (tidyAlt env') alts)
tidyExpr env (Lam b e)
- = tidyBndr env b `thenUs` \ (env', b) ->
- tidyExpr env' e `thenUs` \ e ->
- returnUs (Lam b e)
+ = tidyBndr env b =: \ (env', b) ->
+ Lam b (tidyExpr env' e)
tidyAlt env (con, vs, rhs)
- = tidyBndrs env vs `thenUs` \ (env', vs) ->
- tidyExpr env' rhs `thenUs` \ rhs ->
- returnUs (con, vs, rhs)
+ = tidyBndrs env vs =: \ (env', vs) ->
+ (con, vs, tidyExpr env' rhs)
tidyNote env (Coerce t1 t2) = Coerce (tidyType env t1) (tidyType env t2)
tidyNote env note = note
Nothing -> v
-- tidyBndr is used for lambda and case binders
-tidyBndr :: TidyEnv -> Var -> UniqSM (TidyEnv, Var)
+tidyBndr :: TidyEnv -> Var -> (TidyEnv, Var)
tidyBndr env var
- | isTyVar var = returnUs (tidyTyVar env var)
- | otherwise = tidyId env var noCafIdInfo
-
-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 = noCafIdInfo `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 -> IdInfo -> UniqSM (TidyEnv, Id)
-tidyId env@(tidy_env, var_env) id idinfo
- = -- Non-top-level variables
- getUniqueUs `thenUs` \ uniq ->
+ | isTyVar var = tidyTyVarBndr env var
+ | otherwise = tidyIdBndr env var
+
+tidyBndrs :: TidyEnv -> [Var] -> (TidyEnv, [Var])
+tidyBndrs env vars = mapAccumL tidyBndr env vars
+
+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 uniq occ' noSrcLoc
- (tidy_env', occ') = tidyOccName tidy_env (getOccName id)
- ty' = tidyType (tidy_env,var_env) (idType id)
- id' = mkLocalIdWithInfo name' ty' idinfo
+ --
+ -- All nested Ids now have the same IdInfo, namely none,
+ -- which should save some space.
+ ty' = tidyType env (idType id)
+ id' = mkUserLocal occ' (idUnique id) ty' noSrcLoc
var_env' = extendVarEnv var_env id id'
in
- returnUs ((tidy_env', var_env'), id')
-
-
-fiddleCCall id
- = case globalIdDetails id of
- PrimOpId (CCallOp ccall) ->
- -- Make a guaranteed unique name for a dynamic ccall.
- getUniqueUs `thenUs` \ uniq ->
- returnUs (setGlobalIdDetails id
- (PrimOpId (CCallOp (setCCallUnique ccall uniq))))
- other -> returnUs id
+ ((tidy_env', var_env'), id')
+ }
\end{code}
-%************************************************************************
-%* *
-\subsection{Figuring out CafInfo for an expression}
-%* *
-%************************************************************************
-
-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.
-
-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
-
-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.
-
\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
- 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 globalIdDetails 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
+m =: k = m `seq` k m
\end{code}
projects / ghc-hetmet.git / blobdiff