#include "HsVersions.h"
import CoreSyn
-import CoreUtils
+import CoreUtils ( rhsIsStatic, manifestArity, exprType, findDefault )
import StgSyn
import Type
import TyCon ( isAlgTyCon )
-import Literal
import Id
-import Var ( Var, globalIdDetails )
+import Var ( Var, globalIdDetails, idType )
+import TyCon ( isUnboxedTupleTyCon, isPrimTyCon, isFunTyCon, isHiBootTyCon )
+#ifdef ILX
+import MkId ( unsafeCoerceId )
+#endif
import IdInfo
import DataCon
import CostCentre ( noCCS )
import VarSet
import VarEnv
-import DataCon ( dataConWrapId )
-import IdInfo ( OccInfo(..) )
-import TysPrim ( foreignObjPrimTyCon )
import Maybes ( maybeToBool )
-import Name ( getOccName, isExternallyVisibleName, isDllName )
-import OccName ( occNameUserString )
-import BasicTypes ( TopLevelFlag(..), isNotTopLevel, Arity )
-import CmdLineOpts ( DynFlags, opt_KeepStgTypes )
-import FastTypes hiding ( fastOr )
+import Name ( getOccName, isExternalName, nameOccName )
+import OccName ( occNameString, occNameFS )
+import BasicTypes ( Arity )
+import Packages ( HomeModules )
+import StaticFlags ( opt_RuntimeTypes )
import Outputable
-import List ( partition )
-
infixr 9 `thenLne`
\end{code}
one or more CAFs, or
- NoCafRefs if it definitely doesn't
-we collect the CafInfo first by analysing the original Core expression, and
-also place this information in the environment.
+The CafInfo has already been calculated during the CoreTidy pass.
During CoreToStg, we then pin onto each binding and case expression, a
list of Ids which represents the "live" CAFs at that point. The meaning
the actual nested SRTs, and replaces the lists of Ids with (offset,length)
pairs.
+
+Interaction of let-no-escape with SRTs [Sept 01]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Consider
+
+ let-no-escape x = ...caf1...caf2...
+ in
+ ...x...x...x...
+
+where caf1,caf2 are CAFs. Since x doesn't have a closure, we
+build SRTs just as if x's defn was inlined at each call site, and
+that means that x's CAF refs get duplicated in the overall SRT.
+
+This is unlike ordinary lets, in which the CAF refs are not duplicated.
+
+We could fix this loss of (static) sharing by making a sort of pseudo-closure
+for x, solely to put in the SRTs lower down.
+
+
%************************************************************************
%* *
\subsection[binds-StgVarInfo]{Setting variable info: top-level, binds, RHSs}
%************************************************************************
\begin{code}
-coreToStg :: DynFlags -> [CoreBind] -> IO [StgBinding]
-coreToStg dflags pgm
+coreToStg :: HomeModules -> [CoreBind] -> IO [StgBinding]
+coreToStg hmods pgm
= return pgm'
- where (_, _, pgm') = coreTopBindsToStg emptyVarEnv pgm
+ where (_, _, pgm') = coreTopBindsToStg hmods emptyVarEnv pgm
coreExprToStg :: CoreExpr -> StgExpr
coreExprToStg expr
coreTopBindsToStg
- :: IdEnv HowBound -- environment for the bindings
+ :: HomeModules
+ -> IdEnv HowBound -- environment for the bindings
-> [CoreBind]
-> (IdEnv HowBound, FreeVarsInfo, [StgBinding])
-coreTopBindsToStg env [] = (env, emptyFVInfo, [])
-coreTopBindsToStg env (b:bs)
+coreTopBindsToStg hmods env [] = (env, emptyFVInfo, [])
+coreTopBindsToStg hmods env (b:bs)
= (env2, fvs2, b':bs')
where
-- env accumulates down the list of binds, fvs accumulates upwards
- (env1, fvs2, b' ) = coreTopBindToStg env fvs1 b
- (env2, fvs1, bs') = coreTopBindsToStg env1 bs
+ (env1, fvs2, b' ) = coreTopBindToStg hmods env fvs1 b
+ (env2, fvs1, bs') = coreTopBindsToStg hmods env1 bs
coreTopBindToStg
- :: IdEnv HowBound
+ :: HomeModules
+ -> IdEnv HowBound
-> FreeVarsInfo -- Info about the body
-> CoreBind
-> (IdEnv HowBound, FreeVarsInfo, StgBinding)
-coreTopBindToStg env body_fvs (NonRec id rhs)
+coreTopBindToStg hmods env body_fvs (NonRec id rhs)
= let
- caf_info = hasCafRefs env rhs
-
- env' = extendVarEnv env id (LetBound how_bound emptyLVS (predictArity rhs))
-
- how_bound | mayHaveCafRefs caf_info = TopLevelHasCafs
- | otherwise = TopLevelNoCafs
+ env' = extendVarEnv env id how_bound
+ how_bound = LetBound TopLet $! manifestArity rhs
- (stg_rhs, fvs', cafs) =
+ (stg_rhs, fvs') =
initLne env (
- coreToStgRhs body_fvs TopLevel (id,rhs)
- `thenLne` \ (stg_rhs, fvs', _) ->
- freeVarsToLiveVars fvs' `thenLne` \ (_, cafs) ->
- returnLne (stg_rhs, fvs', cafs)
+ coreToTopStgRhs hmods body_fvs (id,rhs) `thenLne` \ (stg_rhs, fvs') ->
+ returnLne (stg_rhs, fvs')
)
- bind = StgNonRec (SRTEntries cafs) id stg_rhs
+ bind = StgNonRec id stg_rhs
in
- ASSERT2(predictArity rhs == stgRhsArity stg_rhs, ppr id)
- ASSERT2(consistent caf_info bind, ppr id)
+ ASSERT2(manifestArity rhs == stgRhsArity stg_rhs, ppr id)
+ ASSERT2(consistentCafInfo id bind, ppr id)
-- WARN(not (consistent caf_info bind), ppr id <+> ppr cafs <+> ppCafInfo caf_info)
(env', fvs' `unionFVInfo` body_fvs, bind)
-coreTopBindToStg env body_fvs (Rec pairs)
+coreTopBindToStg hmods env body_fvs (Rec pairs)
= let
(binders, rhss) = unzip pairs
- -- to calculate caf_info, we initially map all the binders to
- -- TopLevelNoCafs.
- env1 = extendVarEnvList env
- [ (b, LetBound TopLevelNoCafs emptyLVS (error "no arity"))
- | b <- binders ]
+ extra_env' = [ (b, LetBound TopLet $! manifestArity rhs)
+ | (b, rhs) <- pairs ]
+ env' = extendVarEnvList env extra_env'
- caf_info = hasCafRefss env1{-NB: not env'-} rhss
-
- env' = extendVarEnvList env
- [ (b, LetBound how_bound emptyLVS (predictArity rhs))
- | (b,rhs) <- pairs ]
-
- how_bound | mayHaveCafRefs caf_info = TopLevelHasCafs
- | otherwise = TopLevelNoCafs
-
- (stg_rhss, fvs', cafs)
+ (stg_rhss, fvs')
= initLne env' (
- mapAndUnzip3Lne (coreToStgRhs body_fvs TopLevel) pairs
- `thenLne` \ (stg_rhss, fvss', _) ->
+ mapAndUnzipLne (coreToTopStgRhs hmods body_fvs) pairs
+ `thenLne` \ (stg_rhss, fvss') ->
let fvs' = unionFVInfos fvss' in
- freeVarsToLiveVars fvs' `thenLne` \ (_, cafs) ->
- returnLne (stg_rhss, fvs', cafs)
+ returnLne (stg_rhss, fvs')
)
- bind = StgRec (SRTEntries cafs) (zip binders stg_rhss)
+ bind = StgRec (zip binders stg_rhss)
in
- ASSERT2(and [predictArity rhs == stgRhsArity stg_rhs | (rhs,stg_rhs) <- rhss `zip` stg_rhss], ppr binders)
- ASSERT2(consistent caf_info bind, ppr binders)
--- WARN(not (consistent caf_info bind), ppr binders <+> ppr cafs <+> ppCafInfo caf_info)
+ ASSERT2(and [manifestArity rhs == stgRhsArity stg_rhs | (rhs,stg_rhs) <- rhss `zip` stg_rhss], ppr binders)
+ ASSERT2(consistentCafInfo (head binders) bind, ppr binders)
(env', fvs' `unionFVInfo` body_fvs, bind)
--- assertion helper
-consistent caf_info bind = mayHaveCafRefs caf_info == stgBindHasCafRefs bind
+#ifdef DEBUG
+-- Assertion helper: this checks that the CafInfo on the Id matches
+-- what CoreToStg has figured out about the binding's SRT. The
+-- CafInfo will be exact in all cases except when CorePrep has
+-- floated out a binding, in which case it will be approximate.
+consistentCafInfo id bind
+ | occNameFS (nameOccName (idName id)) == FSLIT("sat")
+ = safe
+ | otherwise
+ = WARN (not exact, ppr id) safe
+ where
+ safe = id_marked_caffy || not binding_is_caffy
+ exact = id_marked_caffy == binding_is_caffy
+ id_marked_caffy = mayHaveCafRefs (idCafInfo id)
+ binding_is_caffy = stgBindHasCafRefs bind
+#endif
\end{code}
\begin{code}
-coreToStgRhs
- :: FreeVarsInfo -- Free var info for the scope of the binding
- -> TopLevelFlag
+coreToTopStgRhs
+ :: HomeModules
+ -> FreeVarsInfo -- Free var info for the scope of the binding
-> (Id,CoreExpr)
- -> LneM (StgRhs, FreeVarsInfo, EscVarsSet)
+ -> LneM (StgRhs, FreeVarsInfo)
-coreToStgRhs scope_fv_info top (binder, rhs)
- = coreToStgExpr rhs `thenLne` \ (new_rhs, rhs_fvs, rhs_escs) ->
- returnLne (mkStgRhs top rhs_fvs binder_info new_rhs,
- rhs_fvs, rhs_escs)
+coreToTopStgRhs hmods scope_fv_info (bndr, rhs)
+ = coreToStgExpr rhs `thenLne` \ (new_rhs, rhs_fvs, _) ->
+ freeVarsToLiveVars rhs_fvs `thenLne` \ lv_info ->
+ returnLne (mkTopStgRhs is_static rhs_fvs (mkSRT lv_info) bndr_info new_rhs, rhs_fvs)
where
- binder_info = lookupFVInfo scope_fv_info binder
+ bndr_info = lookupFVInfo scope_fv_info bndr
+ is_static = rhsIsStatic hmods rhs
-mkStgRhs :: TopLevelFlag -> FreeVarsInfo -> StgBinderInfo
- -> StgExpr -> StgRhs
+mkTopStgRhs :: Bool -> FreeVarsInfo -> SRT -> StgBinderInfo -> StgExpr
+ -> StgRhs
-mkStgRhs top rhs_fvs binder_info (StgLam _ bndrs body)
- = StgRhsClosure noCCS binder_info
+mkTopStgRhs is_static rhs_fvs srt binder_info (StgLam _ bndrs body)
+ = ASSERT( is_static )
+ StgRhsClosure noCCS binder_info
(getFVs rhs_fvs)
ReEntrant
+ srt
bndrs body
-mkStgRhs top rhs_fvs binder_info (StgConApp con args)
- | isNotTopLevel top || not (isDllConApp con args)
+mkTopStgRhs is_static rhs_fvs srt binder_info (StgConApp con args)
+ | is_static -- StgConApps can be updatable (see isCrossDllConApp)
= StgRhsCon noCCS con args
-mkStgRhs top rhs_fvs binder_info rhs
- = StgRhsClosure noCCS binder_info
+mkTopStgRhs is_static rhs_fvs srt binder_info rhs
+ = ASSERT2( not is_static, ppr rhs )
+ StgRhsClosure noCCS binder_info
(getFVs rhs_fvs)
- (updatable [] rhs)
+ Updatable
+ srt
[] rhs
- where
- updatable args body | null args && isPAP body = ReEntrant
- | otherwise = Updatable
-{- ToDo:
- upd = if isOnceDem dem
- then (if isNotTop toplev
- then SingleEntry -- HA! Paydirt for "dem"
- else
-#ifdef DEBUG
- trace "WARNING: SE CAFs unsupported, forcing UPD instead" $
-#endif
- Updatable)
- else Updatable
- -- For now we forbid SingleEntry CAFs; they tickle the
- -- ASSERT in rts/Storage.c line 215 at newCAF() re mut_link,
- -- and I don't understand why. There's only one SE_CAF (well,
- -- only one that tickled a great gaping bug in an earlier attempt
- -- at ClosureInfo.getEntryConvention) in the whole of nofib,
- -- specifically Main.lvl6 in spectral/cryptarithm2.
- -- So no great loss. KSW 2000-07.
--}
-\end{code}
-
-Detect thunks which will reduce immediately to PAPs, and make them
-non-updatable. This has several advantages:
-
- - the non-updatable thunk behaves exactly like the PAP,
-
- - the thunk is more efficient to enter, because it is
- specialised to the task.
-
- - we save one update frame, one stg_update_PAP, one update
- and lots of PAP_enters.
-
- - in the case where the thunk is top-level, we save building
- a black hole and futhermore the thunk isn't considered to
- be a CAF any more, so it doesn't appear in any SRTs.
-
-We do it here, because the arity information is accurate, and we need
-to do it before the SRT pass to save the SRT entries associated with
-any top-level PAPs.
-
-\begin{code}
-isPAP (StgApp f args) = idArity f > length args
-isPAP _ = False
\end{code}
(f, args) = myCollectArgs expr
coreToStgExpr expr@(Lam _ _)
- = let (args, body) = myCollectBinders expr
+ = let
+ (args, body) = myCollectBinders expr
args' = filterStgBinders args
in
extendVarEnvLne [ (a, LambdaBound) | a <- args' ] $
coreToStgExpr body `thenLne` \ (body, body_fvs, body_escs) ->
let
- set_of_args = mkVarSet args'
fvs = args' `minusFVBinders` body_fvs
- escs = body_escs `minusVarSet` set_of_args
+ escs = body_escs `delVarSetList` args'
result_expr | null args' = body
| otherwise = StgLam (exprType expr) args' body
in
= coreToStgExpr expr `thenLne` ( \ (expr2, fvs, escs) ->
returnLne (StgSCC cc expr2, fvs, escs) )
+#ifdef ILX
+-- For ILX, convert (__coerce__ to_ty from_ty e)
+-- into (coerce to_ty from_ty e)
+-- where coerce is real function
+coreToStgExpr (Note (Coerce to_ty from_ty) expr)
+ = coreToStgExpr (mkApps (Var unsafeCoerceId)
+ [Type from_ty, Type to_ty, expr])
+#endif
+
coreToStgExpr (Note other_note expr)
= coreToStgExpr expr
-
-- Cases require a little more real work.
-coreToStgExpr (Case scrut bndr alts)
- = extendVarEnvLne [(bndr, CaseBound)] $
- vars_alts (findDefault alts) `thenLne` \ (alts2, alts_fvs, alts_escs) ->
- freeVarsToLiveVars alts_fvs `thenLne` \ (alts_lvs, alts_caf_refs) ->
+coreToStgExpr (Case scrut bndr _ alts)
+ = extendVarEnvLne [(bndr, LambdaBound)] (
+ mapAndUnzip3Lne vars_alt alts `thenLne` \ (alts2, fvs_s, escs_s) ->
+ returnLne ( alts2,
+ unionFVInfos fvs_s,
+ unionVarSets escs_s )
+ ) `thenLne` \ (alts2, alts_fvs, alts_escs) ->
let
- -- determine whether the default binder is dead or not
+ -- Determine whether the default binder is dead or not
-- This helps the code generator to avoid generating an assignment
-- for the case binder (is extremely rare cases) ToDo: remove.
- bndr'= if (bndr `elementOfFVInfo` alts_fvs)
- then bndr
- else bndr `setIdOccInfo` IAmDead
+ bndr' | bndr `elementOfFVInfo` alts_fvs = bndr
+ | otherwise = bndr `setIdOccInfo` IAmDead
-- Don't consider the default binder as being 'live in alts',
-- since this is from the point of view of the case expr, where
-- the default binder is not free.
- live_in_alts = (alts_lvs `minusVarSet` unitVarSet bndr)
+ alts_fvs_wo_bndr = bndr `minusFVBinder` alts_fvs
+ alts_escs_wo_bndr = alts_escs `delVarSet` bndr
in
- -- we tell the scrutinee that everything live in the alts
- -- is live in it, too.
- setVarsLiveInCont (live_in_alts,alts_caf_refs) (
+
+ freeVarsToLiveVars alts_fvs_wo_bndr `thenLne` \ alts_lv_info ->
+
+ -- We tell the scrutinee that everything
+ -- live in the alts is live in it, too.
+ setVarsLiveInCont alts_lv_info (
coreToStgExpr scrut `thenLne` \ (scrut2, scrut_fvs, scrut_escs) ->
- freeVarsToLiveVars scrut_fvs `thenLne` \ (scrut_lvs, _) ->
- returnLne (scrut2, scrut_fvs, scrut_escs, scrut_lvs)
+ freeVarsToLiveVars scrut_fvs `thenLne` \ scrut_lv_info ->
+ returnLne (scrut2, scrut_fvs, scrut_escs, scrut_lv_info)
)
- `thenLne` \ (scrut2, scrut_fvs, scrut_escs, scrut_lvs) ->
+ `thenLne` \ (scrut2, scrut_fvs, scrut_escs, scrut_lv_info) ->
- let srt = SRTEntries alts_caf_refs
- in
returnLne (
- StgCase scrut2 scrut_lvs live_in_alts bndr' srt alts2,
- bndr `minusFVBinder` (scrut_fvs `unionFVInfo` alts_fvs),
- (alts_escs `minusVarSet` unitVarSet bndr) `unionVarSet` getFVSet scrut_fvs
+ StgCase scrut2 (getLiveVars scrut_lv_info)
+ (getLiveVars alts_lv_info)
+ bndr'
+ (mkSRT alts_lv_info)
+ (mkStgAltType (idType bndr) alts)
+ alts2,
+ scrut_fvs `unionFVInfo` alts_fvs_wo_bndr,
+ alts_escs_wo_bndr `unionVarSet` getFVSet scrut_fvs
-- You might think we should have scrut_escs, not
-- (getFVSet scrut_fvs), but actually we can't call, and
-- then return from, a let-no-escape thing.
)
where
- scrut_ty = idType bndr
- prim_case = isUnLiftedType scrut_ty && not (isUnboxedTupleType scrut_ty)
-
- vars_alts (alts,deflt)
- | prim_case
- = mapAndUnzip3Lne vars_prim_alt alts
- `thenLne` \ (alts2, alts_fvs_list, alts_escs_list) ->
- let
- alts_fvs = unionFVInfos alts_fvs_list
- alts_escs = unionVarSets alts_escs_list
- in
- vars_deflt deflt `thenLne` \ (deflt2, deflt_fvs, deflt_escs) ->
- returnLne (
- mkStgPrimAlts scrut_ty alts2 deflt2,
- alts_fvs `unionFVInfo` deflt_fvs,
- alts_escs `unionVarSet` deflt_escs
- )
-
- | otherwise
- = mapAndUnzip3Lne vars_alg_alt alts
- `thenLne` \ (alts2, alts_fvs_list, alts_escs_list) ->
- let
- alts_fvs = unionFVInfos alts_fvs_list
- alts_escs = unionVarSets alts_escs_list
- in
- vars_deflt deflt `thenLne` \ (deflt2, deflt_fvs, deflt_escs) ->
- returnLne (
- mkStgAlgAlts scrut_ty alts2 deflt2,
- alts_fvs `unionFVInfo` deflt_fvs,
- alts_escs `unionVarSet` deflt_escs
- )
-
- where
- vars_prim_alt (LitAlt lit, _, rhs)
- = coreToStgExpr rhs `thenLne` \ (rhs2, rhs_fvs, rhs_escs) ->
- returnLne ((lit, rhs2), rhs_fvs, rhs_escs)
-
- vars_alg_alt (DataAlt con, binders, rhs)
- = let
- -- remove type variables
- binders' = filterStgBinders binders
- in
- extendVarEnvLne [(b, CaseBound) | b <- binders'] $
- coreToStgExpr rhs `thenLne` \ (rhs2, rhs_fvs, rhs_escs) ->
- let
- good_use_mask = [ b `elementOfFVInfo` rhs_fvs | b <- binders' ]
- -- records whether each param is used in the RHS
- in
- returnLne (
- (con, binders', good_use_mask, rhs2),
- binders' `minusFVBinders` rhs_fvs,
- rhs_escs `minusVarSet` mkVarSet binders'
- -- ToDo: remove the minusVarSet;
- -- since escs won't include any of these binders
- )
- vars_alg_alt other = pprPanic "vars_alg_alt" (ppr other)
-
- vars_deflt Nothing
- = returnLne (StgNoDefault, emptyFVInfo, emptyVarSet)
-
- vars_deflt (Just rhs)
- = coreToStgExpr rhs `thenLne` \ (rhs2, rhs_fvs, rhs_escs) ->
- returnLne (StgBindDefault rhs2, rhs_fvs, rhs_escs)
+ vars_alt (con, binders, rhs)
+ = let -- Remove type variables
+ binders' = filterStgBinders binders
+ in
+ extendVarEnvLne [(b, LambdaBound) | b <- binders'] $
+ coreToStgExpr rhs `thenLne` \ (rhs2, rhs_fvs, rhs_escs) ->
+ let
+ -- Records whether each param is used in the RHS
+ good_use_mask = [ b `elementOfFVInfo` rhs_fvs | b <- binders' ]
+ in
+ returnLne ( (con, binders', good_use_mask, rhs2),
+ binders' `minusFVBinders` rhs_fvs,
+ rhs_escs `delVarSetList` binders' )
+ -- ToDo: remove the delVarSet;
+ -- since escs won't include any of these binders
\end{code}
Lets not only take quite a bit of work, but this is where we convert
returnLne (new_let, fvs, escs)
\end{code}
-If we've got a case containing a _ccall_GC_ primop, we need to
-ensure that the arguments are kept live for the duration of the
-call. This only an issue
-
\begin{code}
-isForeignObjArg :: Id -> Bool
-isForeignObjArg x = isId x && isForeignObjPrimTy (idType x)
+mkStgAltType scrut_ty alts
+ = case splitTyConApp_maybe (repType scrut_ty) of
+ Just (tc,_) | isUnboxedTupleTyCon tc -> UbxTupAlt tc
+ | isPrimTyCon tc -> PrimAlt tc
+ | isHiBootTyCon tc -> look_for_better_tycon
+ | isAlgTyCon tc -> AlgAlt tc
+ | isFunTyCon tc -> PolyAlt
+ | otherwise -> pprPanic "mkStgAlts" (ppr tc)
+ Nothing -> PolyAlt
-isForeignObjPrimTy ty
- = case splitTyConApp_maybe ty of
- Just (tycon, _) -> tycon == foreignObjPrimTyCon
- Nothing -> False
-\end{code}
-
-\begin{code}
-mkStgAlgAlts ty alts deflt
- = case alts of
- -- Get the tycon from the data con
- (dc, _, _, _) : _rest
- -> StgAlgAlts (Just (dataConTyCon dc)) alts deflt
-
- -- Otherwise just do your best
- [] -> case splitTyConApp_maybe (repType ty) of
- Just (tc,_) | isAlgTyCon tc
- -> StgAlgAlts (Just tc) alts deflt
- other
- -> StgAlgAlts Nothing alts deflt
-
-mkStgPrimAlts ty alts deflt
- = StgPrimAlts (tyConAppTyCon ty) alts deflt
+ where
+ -- Sometimes, the TyCon in the type of the scrutinee is an HiBootTyCon,
+ -- which may not have any constructors inside it. If so, then we
+ -- can get a better TyCon by grabbing the one from a constructor alternative
+ -- if one exists.
+ look_for_better_tycon
+ | ((DataAlt con, _, _) : _) <- data_alts =
+ AlgAlt (dataConTyCon con)
+ | otherwise =
+ ASSERT(null data_alts)
+ PolyAlt
+ where
+ (data_alts, _deflt) = findDefault alts
\end{code}
let
n_val_args = valArgCount args
not_letrec_bound = not (isLetBound how_bound)
- fun_fvs = singletonFVInfo f how_bound fun_occ
-
- f_arity = case how_bound of
- LetBound _ _ arity -> arity
- _ -> 0
+ fun_fvs
+ = let fvs = singletonFVInfo f how_bound fun_occ in
+ -- e.g. (f :: a -> int) (x :: a)
+ -- Here the free variables are "f", "x" AND the type variable "a"
+ -- coreToStgArgs will deal with the arguments recursively
+ if opt_RuntimeTypes then
+ fvs `unionFVInfo` tyvarFVInfo (tyVarsOfType (idType f))
+ else fvs
+
+ -- Mostly, the arity info of a function is in the fn's IdInfo
+ -- But new bindings introduced by CoreSat may not have no
+ -- arity info; it would do us no good anyway. For example:
+ -- let f = \ab -> e in f
+ -- No point in having correct arity info for f!
+ -- Hence the hasArity stuff below.
+ -- NB: f_arity is only consulted for LetBound things
+ f_arity = stgArity f how_bound
+ saturated = f_arity <= n_val_args
fun_occ
- | not_letrec_bound = noBinderInfo -- Uninteresting variable
- | f_arity > 0 && f_arity <= n_val_args = stgSatOcc -- Saturated or over-saturated function call
- | otherwise = stgUnsatOcc -- Unsaturated function or thunk
+ | not_letrec_bound = noBinderInfo -- Uninteresting variable
+ | f_arity > 0 && saturated = stgSatOcc -- Saturated or over-saturated function call
+ | otherwise = stgUnsatOcc -- Unsaturated function or thunk
fun_escs
| not_letrec_bound = emptyVarSet -- Only letrec-bound escapees are interesting
-- continuation, but it does no harm to just union the
-- two regardless.
+ res_ty = exprType (mkApps (Var f) args)
app = case globalIdDetails f of
- DataConId dc -> StgConApp dc args'
- PrimOpId op -> StgPrimApp op args' (exprType (mkApps (Var f) args))
- _other -> StgApp f args'
+ DataConWorkId dc | saturated -> StgConApp dc args'
+ PrimOpId op -> ASSERT( saturated )
+ StgOpApp (StgPrimOp op) args' res_ty
+ FCallId call -> ASSERT( saturated )
+ StgOpApp (StgFCallOp call (idUnique f)) args' res_ty
+ _other -> StgApp f args'
in
returnLne (
coreToStgArgs (Type ty : args) -- Type argument
= coreToStgArgs args `thenLne` \ (args', fvs) ->
- if opt_KeepStgTypes then
+ if opt_RuntimeTypes then
returnLne (StgTypeArg ty : args', fvs `unionFVInfo` tyvarFVInfo (tyVarsOfType ty))
else
returnLne (args', fvs)
fvs = args_fvs `unionFVInfo` arg_fvs
stg_arg = case arg' of
StgApp v [] -> StgVarArg v
- StgConApp con [] -> StgVarArg (dataConWrapId con)
+ StgConApp con [] -> StgVarArg (dataConWorkId con)
StgLit lit -> StgLitArg lit
_ -> pprPanic "coreToStgArgs" (ppr arg)
in
-- is among the escaping vars
coreToStgLet let_no_escape bind body
- = fixLne (\ ~(_, _, _, _, _, _, rec_body_fvs, _, _) ->
+ = fixLne (\ ~(_, _, _, _, _, rec_body_fvs, _, _) ->
-- Do the bindings, setting live_in_cont to empty if
-- we ain't in a let-no-escape world
getVarsLiveInCont `thenLne` \ live_in_cont ->
setVarsLiveInCont (if let_no_escape
then live_in_cont
- else emptyLVS)
+ else emptyLiveInfo)
(vars_bind rec_body_fvs bind)
- `thenLne` \ ( bind2, bind_fvs, bind_escs
- , bind_lvs, bind_cafs, env_ext) ->
+ `thenLne` \ ( bind2, bind_fvs, bind_escs, bind_lv_info, env_ext) ->
-- Do the body
extendVarEnvLne env_ext (
coreToStgExpr body `thenLne` \(body2, body_fvs, body_escs) ->
- freeVarsToLiveVars body_fvs `thenLne` \(body_lvs, _) ->
+ freeVarsToLiveVars body_fvs `thenLne` \ body_lv_info ->
- returnLne (bind2, bind_fvs, bind_escs, bind_lvs, bind_cafs,
- body2, body_fvs, body_escs, body_lvs)
+ returnLne (bind2, bind_fvs, bind_escs, getLiveVars bind_lv_info,
+ body2, body_fvs, body_escs, getLiveVars body_lv_info)
)
- ) `thenLne` (\ (bind2, bind_fvs, bind_escs, bind_lvs, bind_cafs,
+ ) `thenLne` (\ (bind2, bind_fvs, bind_escs, bind_lvs,
body2, body_fvs, body_escs, body_lvs) ->
= binders `minusFVBinders` (bind_fvs `unionFVInfo` body_fvs)
live_in_whole_let
- = bind_lvs `unionVarSet` (body_lvs `minusVarSet` set_of_binders)
+ = bind_lvs `unionVarSet` (body_lvs `delVarSetList` binders)
real_bind_escs = if let_no_escape then
bind_escs
getFVSet bind_fvs
-- Everything escapes which is free in the bindings
- let_escs = (real_bind_escs `unionVarSet` body_escs) `minusVarSet` set_of_binders
+ let_escs = (real_bind_escs `unionVarSet` body_escs) `delVarSetList` binders
all_escs = bind_escs `unionVarSet` body_escs -- Still includes binders of
-- this let(rec)
))
where
set_of_binders = mkVarSet binders
- binders = case bind of
- NonRec binder rhs -> [binder]
- Rec pairs -> map fst pairs
+ binders = bindersOf bind
- mk_binding bind_lvs bind_cafs binder rhs
- = (binder, LetBound NotTopLevelBound -- Not top level
- live_vars (predictArity rhs)
- )
+ mk_binding bind_lv_info binder rhs
+ = (binder, LetBound (NestedLet live_vars) (manifestArity rhs))
where
- live_vars = if let_no_escape then
- (extendVarSet bind_lvs binder, bind_cafs)
- else
- (unitVarSet binder, emptyVarSet)
+ live_vars | let_no_escape = addLiveVar bind_lv_info binder
+ | otherwise = unitLiveVar binder
+ -- c.f. the invariant on NestedLet
vars_bind :: FreeVarsInfo -- Free var info for body of binding
-> CoreBind
-> LneM (StgBinding,
FreeVarsInfo,
EscVarsSet, -- free vars; escapee vars
- StgLiveVars, -- vars live in binding
- IdSet, -- CAFs live in binding
+ LiveInfo, -- Vars and CAFs live in binding
[(Id, HowBound)]) -- extension to environment
vars_bind body_fvs (NonRec binder rhs)
- = coreToStgRhs body_fvs NotTopLevel (binder,rhs)
- `thenLne` \ (rhs2, bind_fvs, escs) ->
-
- freeVarsToLiveVars bind_fvs `thenLne` \ (bind_lvs, bind_cafs) ->
+ = coreToStgRhs body_fvs [] (binder,rhs)
+ `thenLne` \ (rhs2, bind_fvs, bind_lv_info, escs) ->
let
- env_ext_item = mk_binding bind_lvs bind_cafs binder rhs
+ env_ext_item = mk_binding bind_lv_info binder rhs
in
- returnLne (StgNonRec (SRTEntries bind_cafs) binder rhs2,
- bind_fvs, escs, bind_lvs, bind_cafs, [env_ext_item])
+ returnLne (StgNonRec binder rhs2,
+ bind_fvs, escs, bind_lv_info, [env_ext_item])
vars_bind body_fvs (Rec pairs)
- = fixLne (\ ~(_, rec_rhs_fvs, _, bind_lvs, bind_cafs, _) ->
+ = fixLne (\ ~(_, rec_rhs_fvs, _, bind_lv_info, _) ->
let
rec_scope_fvs = unionFVInfo body_fvs rec_rhs_fvs
binders = map fst pairs
- env_ext = [ mk_binding bind_lvs bind_cafs b rhs
+ env_ext = [ mk_binding bind_lv_info b rhs
| (b,rhs) <- pairs ]
in
extendVarEnvLne env_ext (
- mapAndUnzip3Lne (coreToStgRhs rec_scope_fvs NotTopLevel) pairs
- `thenLne` \ (rhss2, fvss, escss) ->
+ mapAndUnzip4Lne (coreToStgRhs rec_scope_fvs binders) pairs
+ `thenLne` \ (rhss2, fvss, lv_infos, escss) ->
let
bind_fvs = unionFVInfos fvss
+ bind_lv_info = foldr unionLiveInfo emptyLiveInfo lv_infos
escs = unionVarSets escss
in
- freeVarsToLiveVars (binders `minusFVBinders` bind_fvs)
- `thenLne` \ (bind_lvs, bind_cafs) ->
-
- returnLne (StgRec (SRTEntries bind_cafs) (binders `zip` rhss2),
- bind_fvs, escs, bind_lvs, bind_cafs, env_ext)
+ returnLne (StgRec (binders `zip` rhss2),
+ bind_fvs, escs, bind_lv_info, env_ext)
)
)
is_join_var :: Id -> Bool
-- A hack (used only for compiler debuggging) to tell if
-- a variable started life as a join point ($j)
-is_join_var j = occNameUserString (getOccName j) == "$j"
+is_join_var j = occNameString (getOccName j) == "$j"
\end{code}
-%************************************************************************
-%* *
-\subsection{Arity prediction}
-%* *
-%************************************************************************
+\begin{code}
+coreToStgRhs :: FreeVarsInfo -- Free var info for the scope of the binding
+ -> [Id]
+ -> (Id,CoreExpr)
+ -> LneM (StgRhs, FreeVarsInfo, LiveInfo, EscVarsSet)
+
+coreToStgRhs scope_fv_info binders (bndr, rhs)
+ = coreToStgExpr rhs `thenLne` \ (new_rhs, rhs_fvs, rhs_escs) ->
+ getEnvLne `thenLne` \ env ->
+ freeVarsToLiveVars (binders `minusFVBinders` rhs_fvs) `thenLne` \ lv_info ->
+ returnLne (mkStgRhs rhs_fvs (mkSRT lv_info) bndr_info new_rhs,
+ rhs_fvs, lv_info, rhs_escs)
+ where
+ bndr_info = lookupFVInfo scope_fv_info bndr
-To avoid yet another knot, we predict the arity of each function from
-its Core form, based on the number of visible top-level lambdas.
-It should be the same as the arity of the STG RHS!
+mkStgRhs :: FreeVarsInfo -> SRT -> StgBinderInfo -> StgExpr -> StgRhs
-\begin{code}
-predictArity :: CoreExpr -> Int
-predictArity (Lam x e)
- | isTyVar x = predictArity e
- | otherwise = 1 + predictArity e
-predictArity (Note _ e)
- -- Ignore coercions. Top level sccs are removed by the final
- -- profiling pass, so we ignore those too.
- = predictArity e
-predictArity _ = 0
+mkStgRhs rhs_fvs srt binder_info (StgConApp con args)
+ = StgRhsCon noCCS con args
+
+mkStgRhs rhs_fvs srt binder_info (StgLam _ bndrs body)
+ = StgRhsClosure noCCS binder_info
+ (getFVs rhs_fvs)
+ ReEntrant
+ srt bndrs body
+
+mkStgRhs rhs_fvs srt binder_info rhs
+ = StgRhsClosure noCCS binder_info
+ (getFVs rhs_fvs)
+ upd_flag srt [] rhs
+ where
+ upd_flag = Updatable
+ {-
+ SDM: disabled. Eval/Apply can't handle functions with arity zero very
+ well; and making these into simple non-updatable thunks breaks other
+ assumptions (namely that they will be entered only once).
+
+ upd_flag | isPAP env rhs = ReEntrant
+ | otherwise = Updatable
+ -}
+
+{- ToDo:
+ upd = if isOnceDem dem
+ then (if isNotTop toplev
+ then SingleEntry -- HA! Paydirt for "dem"
+ else
+#ifdef DEBUG
+ trace "WARNING: SE CAFs unsupported, forcing UPD instead" $
+#endif
+ Updatable)
+ else Updatable
+ -- For now we forbid SingleEntry CAFs; they tickle the
+ -- ASSERT in rts/Storage.c line 215 at newCAF() re mut_link,
+ -- and I don't understand why. There's only one SE_CAF (well,
+ -- only one that tickled a great gaping bug in an earlier attempt
+ -- at ClosureInfo.getEntryConvention) in the whole of nofib,
+ -- specifically Main.lvl6 in spectral/cryptarithm2.
+ -- So no great loss. KSW 2000-07.
+-}
\end{code}
+Detect thunks which will reduce immediately to PAPs, and make them
+non-updatable. This has several advantages:
+
+ - the non-updatable thunk behaves exactly like the PAP,
+
+ - the thunk is more efficient to enter, because it is
+ specialised to the task.
+
+ - we save one update frame, one stg_update_PAP, one update
+ and lots of PAP_enters.
+
+ - in the case where the thunk is top-level, we save building
+ a black hole and futhermore the thunk isn't considered to
+ be a CAF any more, so it doesn't appear in any SRTs.
+
+We do it here, because the arity information is accurate, and we need
+to do it before the SRT pass to save the SRT entries associated with
+any top-level PAPs.
+
+isPAP env (StgApp f args) = listLengthCmp args arity == LT -- idArity f > length args
+ where
+ arity = stgArity f (lookupBinding env f)
+isPAP env _ = False
+
%************************************************************************
%* *
\begin{code}
type LneM a = IdEnv HowBound
- -> (StgLiveVars, -- vars live in continuation
- IdSet) -- cafs live in continuation
+ -> LiveInfo -- Vars and CAFs live in continuation
-> a
+type LiveInfo = (StgLiveVars, -- Dynamic live variables;
+ -- i.e. ones with a nested (non-top-level) binding
+ CafSet) -- Static live variables;
+ -- i.e. top-level variables that are CAFs or refer to them
+
+type EscVarsSet = IdSet
+type CafSet = IdSet
+
data HowBound
- = ImportBound
- | CaseBound
- | LambdaBound
- | LetBound
- TopLevelCafInfo
- (StgLiveVars, IdSet) -- (Live vars, Live CAFs)... see notes below
- Arity -- its arity (local Ids don't have arity info at this point)
-
-isLetBound (LetBound _ _ _) = True
-isLetBound other = False
+ = ImportBound -- Used only as a response to lookupBinding; never
+ -- exists in the range of the (IdEnv HowBound)
+
+ | LetBound -- A let(rec) in this module
+ LetInfo -- Whether top level or nested
+ Arity -- Its arity (local Ids don't have arity info at this point)
+
+ | LambdaBound -- Used for both lambda and case
+
+data LetInfo
+ = TopLet -- top level things
+ | NestedLet LiveInfo -- For nested things, what is live if this
+ -- thing is live? Invariant: the binder
+ -- itself is always a member of
+ -- the dynamic set of its own LiveInfo
+
+isLetBound (LetBound _ _) = True
+isLetBound other = False
+
+topLevelBound ImportBound = True
+topLevelBound (LetBound TopLet _) = True
+topLevelBound other = False
\end{code}
-For a let(rec)-bound variable, x, we record StgLiveVars, the set of
-variables that are live if x is live. For "normal" variables that is
-just x alone. If x is a let-no-escaped variable then x is represented
-by a code pointer and a stack pointer (well, one for each stack). So
-all of the variables needed in the execution of x are live if x is,
-and are therefore recorded in the LetBound constructor; x itself
-*is* included.
+For a let(rec)-bound variable, x, we record LiveInfo, the set of
+variables that are live if x is live. This LiveInfo comprises
+ (a) dynamic live variables (ones with a non-top-level binding)
+ (b) static live variabes (CAFs or things that refer to CAFs)
+
+For "normal" variables (a) is just x alone. If x is a let-no-escaped
+variable then x is represented by a code pointer and a stack pointer
+(well, one for each stack). So all of the variables needed in the
+execution of x are live if x is, and are therefore recorded in the
+LetBound constructor; x itself *is* included.
-The set of live variables is guaranteed ot have no further let-no-escaped
+The set of dynamic live variables is guaranteed ot have no further let-no-escaped
variables in it.
+\begin{code}
+emptyLiveInfo :: LiveInfo
+emptyLiveInfo = (emptyVarSet,emptyVarSet)
+
+unitLiveVar :: Id -> LiveInfo
+unitLiveVar lv = (unitVarSet lv, emptyVarSet)
+
+unitLiveCaf :: Id -> LiveInfo
+unitLiveCaf caf = (emptyVarSet, unitVarSet caf)
+
+addLiveVar :: LiveInfo -> Id -> LiveInfo
+addLiveVar (lvs, cafs) id = (lvs `extendVarSet` id, cafs)
+
+unionLiveInfo :: LiveInfo -> LiveInfo -> LiveInfo
+unionLiveInfo (lv1,caf1) (lv2,caf2) = (lv1 `unionVarSet` lv2, caf1 `unionVarSet` caf2)
+
+mkSRT :: LiveInfo -> SRT
+mkSRT (_, cafs) = SRTEntries cafs
+
+getLiveVars :: LiveInfo -> StgLiveVars
+getLiveVars (lvs, _) = lvs
+\end{code}
+
+
The std monad functions:
\begin{code}
initLne :: IdEnv HowBound -> LneM a -> a
-initLne env m = m env emptyLVS
+initLne env m = m env emptyLiveInfo
+
-emptyLVS = (emptyVarSet,emptyVarSet)
{-# INLINE thenLne #-}
{-# INLINE returnLne #-}
thenLne m k env lvs_cont
= k (m env lvs_cont) env lvs_cont
-mapLne :: (a -> LneM b) -> [a] -> LneM [b]
-mapLne f [] = returnLne []
-mapLne f (x:xs)
- = f x `thenLne` \ r ->
- mapLne f xs `thenLne` \ rs ->
- returnLne (r:rs)
-
mapAndUnzipLne :: (a -> LneM (b,c)) -> [a] -> LneM ([b],[c])
-
mapAndUnzipLne f [] = returnLne ([],[])
mapAndUnzipLne f (x:xs)
= f x `thenLne` \ (r1, r2) ->
returnLne (r1:rs1, r2:rs2)
mapAndUnzip3Lne :: (a -> LneM (b,c,d)) -> [a] -> LneM ([b],[c],[d])
-
mapAndUnzip3Lne f [] = returnLne ([],[],[])
mapAndUnzip3Lne f (x:xs)
= f x `thenLne` \ (r1, r2, r3) ->
mapAndUnzip3Lne f xs `thenLne` \ (rs1, rs2, rs3) ->
returnLne (r1:rs1, r2:rs2, r3:rs3)
+mapAndUnzip4Lne :: (a -> LneM (b,c,d,e)) -> [a] -> LneM ([b],[c],[d],[e])
+mapAndUnzip4Lne f [] = returnLne ([],[],[],[])
+mapAndUnzip4Lne f (x:xs)
+ = f x `thenLne` \ (r1, r2, r3, r4) ->
+ mapAndUnzip4Lne f xs `thenLne` \ (rs1, rs2, rs3, rs4) ->
+ returnLne (r1:rs1, r2:rs2, r3:rs3, r4:rs4)
+
fixLne :: (a -> LneM a) -> LneM a
fixLne expr env lvs_cont
= result
Functions specific to this monad:
\begin{code}
-getVarsLiveInCont :: LneM (StgLiveVars, IdSet)
+getVarsLiveInCont :: LneM LiveInfo
getVarsLiveInCont env lvs_cont = lvs_cont
-setVarsLiveInCont :: (StgLiveVars,IdSet) -> LneM a -> LneM a
+setVarsLiveInCont :: LiveInfo -> LneM a -> LneM a
setVarsLiveInCont new_lvs_cont expr env lvs_cont
= expr env new_lvs_cont
= expr (extendVarEnvList env ids_w_howbound) lvs_cont
lookupVarLne :: Id -> LneM HowBound
-lookupVarLne v env lvs_cont
- = returnLne (
- case (lookupVarEnv env v) of
- Just xx -> xx
- Nothing -> ImportBound
- ) env lvs_cont
+lookupVarLne v env lvs_cont = returnLne (lookupBinding env v) env lvs_cont
+
+getEnvLne :: LneM (IdEnv HowBound)
+getEnvLne env lvs_cont = returnLne env env lvs_cont
+
+lookupBinding :: IdEnv HowBound -> Id -> HowBound
+lookupBinding env v = case lookupVarEnv env v of
+ Just xx -> xx
+ Nothing -> ASSERT2( isGlobalId v, ppr v ) ImportBound
+
-- The result of lookupLiveVarsForSet, a set of live variables, is
-- only ever tacked onto a decorated expression. It is never used as
-- the basis of a control decision, which might give a black hole.
-freeVarsToLiveVars :: FreeVarsInfo -> LneM (StgLiveVars, IdSet)
+freeVarsToLiveVars :: FreeVarsInfo -> LneM LiveInfo
freeVarsToLiveVars fvs env live_in_cont
- = returnLne (lvs, cafs) env live_in_cont
+ = returnLne live_info env live_in_cont
where
- (lvs_cont, cafs_cont) = live_in_cont -- not a strict pattern match!
- (local, global) = partition isLocalId (allFVs fvs)
-
- (lvs_from_fvs, caf_extras) = unzip (map do_one local)
-
- lvs = unionVarSets lvs_from_fvs
- `unionVarSet` lvs_cont
-
- cafs = mkVarSet (filter is_caf_one global)
- `unionVarSet` (unionVarSets caf_extras)
- `unionVarSet` cafs_cont
-
- do_one v
- = case (lookupVarEnv env v) of
- Just (LetBound _ (lvs,cafs) _) -> (extendVarSet lvs v, cafs)
- Just _ -> (unitVarSet v, emptyVarSet)
- Nothing -> pprPanic "lookupLiveVarsForSet/do_one:" (ppr v)
-
- is_caf_one v
- = case lookupVarEnv env v of
- Just (LetBound TopLevelHasCafs (lvs,_) _) ->
- ASSERT( isEmptyVarSet lvs ) True
- Just (LetBound _ _ _) -> False
- _otherwise -> mayHaveCafRefs (idCafInfo v)
+ live_info = foldr unionLiveInfo live_in_cont lvs_from_fvs
+ lvs_from_fvs = map do_one (allFreeIds fvs)
+
+ do_one (v, how_bound)
+ = case how_bound of
+ ImportBound -> unitLiveCaf v -- Only CAF imports are
+ -- recorded in fvs
+ LetBound TopLet _
+ | mayHaveCafRefs (idCafInfo v) -> unitLiveCaf v
+ | otherwise -> emptyLiveInfo
+
+ LetBound (NestedLet lvs) _ -> lvs -- lvs already contains v
+ -- (see the invariant on NestedLet)
+
+ _lambda_or_case_binding -> unitLiveVar v -- Bound by lambda or case
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-type FreeVarsInfo = VarEnv (Var, TopLevelCafInfo, StgBinderInfo)
+type FreeVarsInfo = VarEnv (Var, HowBound, StgBinderInfo)
+ -- The Var is so we can gather up the free variables
+ -- as a set.
+ --
+ -- The HowBound info just saves repeated lookups;
+ -- we look up just once when we encounter the occurrence.
+ -- INVARIANT: Any ImportBound Ids are HaveCafRef Ids
+ -- Imported Ids without CAF refs are simply
+ -- not put in the FreeVarsInfo for an expression.
+ -- See singletonFVInfo and freeVarsToLiveVars
+ --
+ -- StgBinderInfo records how it occurs; notably, we
+ -- are interested in whether it only occurs in saturated
+ -- applications, because then we don't need to build a
+ -- curried version.
-- If f is mapped to noBinderInfo, that means
-- that f *is* mentioned (else it wouldn't be in the
-- IdEnv at all), but perhaps in an unsaturated applications.
--
-- For ILX we track free var info for type variables too;
-- hence VarEnv not IdEnv
-
-data TopLevelCafInfo
- = NotTopLevelBound
- | TopLevelNoCafs
- | TopLevelHasCafs
- deriving Eq
-
-type EscVarsSet = IdSet
\end{code}
\begin{code}
emptyFVInfo = emptyVarEnv
singletonFVInfo :: Id -> HowBound -> StgBinderInfo -> FreeVarsInfo
+-- Don't record non-CAF imports at all, to keep free-var sets small
singletonFVInfo id ImportBound info
- | mayHaveCafRefs (idCafInfo id) = unitVarEnv id (id, TopLevelHasCafs, info)
+ | mayHaveCafRefs (idCafInfo id) = unitVarEnv id (id, ImportBound, info)
| otherwise = emptyVarEnv
-singletonFVInfo id (LetBound top_level _ _) info
- = unitVarEnv id (id, top_level, info)
-singletonFVInfo id other info
- = unitVarEnv id (id, NotTopLevelBound, info)
+singletonFVInfo id how_bound info = unitVarEnv id (id, how_bound, info)
tyvarFVInfo :: TyVarSet -> FreeVarsInfo
tyvarFVInfo tvs = foldVarSet add emptyFVInfo tvs
where
- add tv fvs = extendVarEnv fvs tv (tv, NotTopLevelBound, noBinderInfo)
+ add tv fvs = extendVarEnv fvs tv (tv, LambdaBound, noBinderInfo)
+ -- Type variables must be lambda-bound
unionFVInfo :: FreeVarsInfo -> FreeVarsInfo -> FreeVarsInfo
unionFVInfo fv1 fv2 = plusVarEnv_C plusFVInfo fv1 fv2
minusFVBinders vs fv = foldr minusFVBinder fv vs
minusFVBinder :: Id -> FreeVarsInfo -> FreeVarsInfo
-minusFVBinder v fv | isId v && opt_KeepStgTypes
+minusFVBinder v fv | isId v && opt_RuntimeTypes
= (fv `delVarEnv` v) `unionFVInfo`
tyvarFVInfo (tyVarsOfType (idType v))
| otherwise = fv `delVarEnv` v
-- Find how the given Id is used.
-- Externally visible things may be used any old how
lookupFVInfo fvs id
- | isExternallyVisibleName (idName id) = noBinderInfo
+ | isExternalName (idName id) = noBinderInfo
| otherwise = case lookupVarEnv fvs id of
Nothing -> noBinderInfo
Just (_,_,info) -> info
-allFVs :: FreeVarsInfo -> [Id] -- Non-top-level things only
-allFVs fvs = [id | (id,_,_) <- rngVarEnv fvs]
+allFreeIds :: FreeVarsInfo -> [(Id,HowBound)] -- Both top level and non-top-level Ids
+allFreeIds fvs = [(id,how_bound) | (id,how_bound,_) <- varEnvElts fvs, isId id]
-getFVs :: FreeVarsInfo -> [Id] -- Non-top-level things only
-getFVs fvs = [id | (id,NotTopLevelBound,_) <- rngVarEnv fvs]
+-- Non-top-level things only, both type variables and ids
+-- (type variables only if opt_RuntimeTypes)
+getFVs :: FreeVarsInfo -> [Var]
+getFVs fvs = [id | (id, how_bound, _) <- varEnvElts fvs,
+ not (topLevelBound how_bound) ]
-getFVSet :: FreeVarsInfo -> IdSet
+getFVSet :: FreeVarsInfo -> VarSet
getFVSet fvs = mkVarSet (getFVs fvs)
-plusFVInfo (id1,top1,info1) (id2,top2,info2)
- = ASSERT (id1 == id2 && top1 == top2)
- (id1, top1, combineStgBinderInfo info1 info2)
+plusFVInfo (id1,hb1,info1) (id2,hb2,info2)
+ = ASSERT (id1 == id2 && hb1 `check_eq_how_bound` hb2)
+ (id1, hb1, combineStgBinderInfo info1 info2)
+
+#ifdef DEBUG
+-- The HowBound info for a variable in the FVInfo should be consistent
+check_eq_how_bound ImportBound ImportBound = True
+check_eq_how_bound LambdaBound LambdaBound = True
+check_eq_how_bound (LetBound li1 ar1) (LetBound li2 ar2) = ar1 == ar2 && check_eq_li li1 li2
+check_eq_how_bound hb1 hb2 = False
+
+check_eq_li (NestedLet _) (NestedLet _) = True
+check_eq_li TopLet TopLet = True
+check_eq_li li1 li2 = False
+#endif
\end{code}
Misc.
\begin{code}
filterStgBinders :: [Var] -> [Var]
filterStgBinders bndrs
- | opt_KeepStgTypes = bndrs
+ | opt_RuntimeTypes = bndrs
| otherwise = filter isId bndrs
\end{code}
go _ as = pprPanic "CoreToStg.myCollectArgs" (ppr expr)
\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 :: IdEnv HowBound -> CoreExpr -> CafInfo
--- Only called for the RHS of top-level lets
-hasCafRefss :: IdEnv HowBound -> [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
- | isCAF expr || isFastTrue (cafRefs p expr) = MayHaveCafRefs
- | otherwise = 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
- | any isCAF exprs || isFastTrue (cafRefss p exprs) = MayHaveCafRefs
- | otherwise = NoCafRefs
-
--- cafRefs compiles to beautiful code :)
-
-cafRefs p (Var id)
- | isLocalId id = fastBool False
- | otherwise =
- case lookupVarEnv p id of
- Just (LetBound TopLevelHasCafs _ _) -> fastBool True
- Just (LetBound _ _ _) -> fastBool False
- Nothing -> fastBool (cgMayHaveCafRefs (idCgInfo id)) -- imported Ids
-
-cafRefs p (Lit l) = fastBool False
-cafRefs p (App f a) = fastOr (cafRefs p f) (cafRefs p) a
-cafRefs p (Lam x e) = cafRefs p e
-cafRefs p (Let b e) = fastOr (cafRefss p (rhssOfBind b)) (cafRefs p) e
-cafRefs p (Case e bndr alts) = fastOr (cafRefs p e)
- (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) = fastOr (cafRefs p e) (cafRefss p) es
-
--- hack for lazy-or over FastBool.
-fastOr a f x = fastBool (isFastTrue a || isFastTrue (f x))
-
-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
- | Just con <- isDataConId_maybe id = not (isDynConApp con args)
- | otherwise = 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
+stgArity :: Id -> HowBound -> Arity
+stgArity f (LetBound _ arity) = arity
+stgArity f ImportBound = idArity f
+stgArity f LambdaBound = 0
\end{code}
projects / ghc-hetmet.git / blobdiff