diff options
Diffstat (limited to 'compiler/GHC/CoreToIface.hs')
| -rw-r--r-- | compiler/GHC/CoreToIface.hs | 685 |
1 files changed, 685 insertions, 0 deletions
diff --git a/compiler/GHC/CoreToIface.hs b/compiler/GHC/CoreToIface.hs new file mode 100644 index 0000000000..65d0da34af --- /dev/null +++ b/compiler/GHC/CoreToIface.hs @@ -0,0 +1,685 @@ +{-# LANGUAGE CPP #-} +{-# LANGUAGE Strict #-} -- See Note [Avoiding space leaks in toIface*] + +-- | Functions for converting Core things to interface file things. +module GHC.CoreToIface + ( -- * Binders + toIfaceTvBndr + , toIfaceTvBndrs + , toIfaceIdBndr + , toIfaceBndr + , toIfaceForAllBndr + , toIfaceTyCoVarBinders + , toIfaceTyVar + -- * Types + , toIfaceType, toIfaceTypeX + , toIfaceKind + , toIfaceTcArgs + , toIfaceTyCon + , toIfaceTyCon_name + , toIfaceTyLit + -- * Tidying types + , tidyToIfaceType + , tidyToIfaceContext + , tidyToIfaceTcArgs + -- * Coercions + , toIfaceCoercion, toIfaceCoercionX + -- * Pattern synonyms + , patSynToIfaceDecl + -- * Expressions + , toIfaceExpr + , toIfaceBang + , toIfaceSrcBang + , toIfaceLetBndr + , toIfaceIdDetails + , toIfaceIdInfo + , toIfUnfolding + , toIfaceOneShot + , toIfaceTickish + , toIfaceBind + , toIfaceAlt + , toIfaceCon + , toIfaceApp + , toIfaceVar + ) where + +#include "HsVersions.h" + +import GhcPrelude + +import GHC.Iface.Syntax +import DataCon +import Id +import IdInfo +import CoreSyn +import TyCon hiding ( pprPromotionQuote ) +import CoAxiom +import TysPrim ( eqPrimTyCon, eqReprPrimTyCon ) +import TysWiredIn ( heqTyCon ) +import MkId ( noinlineIdName ) +import PrelNames +import Name +import BasicTypes +import Type +import PatSyn +import Outputable +import FastString +import Util +import Var +import VarEnv +import VarSet +import TyCoRep +import TyCoTidy ( tidyCo ) +import Demand ( isTopSig ) + +import Data.Maybe ( catMaybes ) + +{- Note [Avoiding space leaks in toIface*] + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Building a interface file depends on the output of the simplifier. +If we build these lazily this would mean keeping the Core AST alive +much longer than necessary causing a space "leak". + +This happens for example when we only write the interface file to disk +after code gen has run, in which case we might carry megabytes of core +AST in the heap which is no longer needed. + +We avoid this in two ways. +* First we use -XStrict in GHC.CoreToIface which avoids many thunks + to begin with. +* Second we define NFData instance for Iface syntax and use them to + force any remaining thunks. + +-XStrict is not sufficient as patterns of the form `f (g x)` would still +result in a thunk being allocated for `g x`. + +NFData is sufficient for the space leak, but using -XStrict reduces allocation +by ~0.1% when compiling with -O. (nofib/spectral/simple, T10370). +It's essentially free performance hence we use -XStrict on top of NFData. + +MR !1633 on gitlab, has more discussion on the topic. +-} + +---------------- +toIfaceTvBndr :: TyVar -> IfaceTvBndr +toIfaceTvBndr = toIfaceTvBndrX emptyVarSet + +toIfaceTvBndrX :: VarSet -> TyVar -> IfaceTvBndr +toIfaceTvBndrX fr tyvar = ( occNameFS (getOccName tyvar) + , toIfaceTypeX fr (tyVarKind tyvar) + ) + +toIfaceTvBndrs :: [TyVar] -> [IfaceTvBndr] +toIfaceTvBndrs = map toIfaceTvBndr + +toIfaceIdBndr :: Id -> IfaceIdBndr +toIfaceIdBndr = toIfaceIdBndrX emptyVarSet + +toIfaceIdBndrX :: VarSet -> CoVar -> IfaceIdBndr +toIfaceIdBndrX fr covar = ( occNameFS (getOccName covar) + , toIfaceTypeX fr (varType covar) + ) + +toIfaceBndr :: Var -> IfaceBndr +toIfaceBndr var + | isId var = IfaceIdBndr (toIfaceIdBndr var) + | otherwise = IfaceTvBndr (toIfaceTvBndr var) + +toIfaceBndrX :: VarSet -> Var -> IfaceBndr +toIfaceBndrX fr var + | isId var = IfaceIdBndr (toIfaceIdBndrX fr var) + | otherwise = IfaceTvBndr (toIfaceTvBndrX fr var) + +toIfaceTyCoVarBinder :: VarBndr Var vis -> VarBndr IfaceBndr vis +toIfaceTyCoVarBinder (Bndr tv vis) = Bndr (toIfaceBndr tv) vis + +toIfaceTyCoVarBinders :: [VarBndr Var vis] -> [VarBndr IfaceBndr vis] +toIfaceTyCoVarBinders = map toIfaceTyCoVarBinder + +{- +************************************************************************ +* * + Conversion from Type to IfaceType +* * +************************************************************************ +-} + +toIfaceKind :: Type -> IfaceType +toIfaceKind = toIfaceType + +--------------------- +toIfaceType :: Type -> IfaceType +toIfaceType = toIfaceTypeX emptyVarSet + +toIfaceTypeX :: VarSet -> Type -> IfaceType +-- (toIfaceTypeX free ty) +-- translates the tyvars in 'free' as IfaceFreeTyVars +-- +-- Synonyms are retained in the interface type +toIfaceTypeX fr (TyVarTy tv) -- See Note [TcTyVars in IfaceType] in GHC.Iface.Type + | tv `elemVarSet` fr = IfaceFreeTyVar tv + | otherwise = IfaceTyVar (toIfaceTyVar tv) +toIfaceTypeX fr ty@(AppTy {}) = + -- Flatten as many argument AppTys as possible, then turn them into an + -- IfaceAppArgs list. + -- See Note [Suppressing invisible arguments] in GHC.Iface.Type. + let (head, args) = splitAppTys ty + in IfaceAppTy (toIfaceTypeX fr head) (toIfaceAppTyArgsX fr head args) +toIfaceTypeX _ (LitTy n) = IfaceLitTy (toIfaceTyLit n) +toIfaceTypeX fr (ForAllTy b t) = IfaceForAllTy (toIfaceForAllBndrX fr b) + (toIfaceTypeX (fr `delVarSet` binderVar b) t) +toIfaceTypeX fr (FunTy { ft_arg = t1, ft_res = t2, ft_af = af }) + = IfaceFunTy af (toIfaceTypeX fr t1) (toIfaceTypeX fr t2) +toIfaceTypeX fr (CastTy ty co) = IfaceCastTy (toIfaceTypeX fr ty) (toIfaceCoercionX fr co) +toIfaceTypeX fr (CoercionTy co) = IfaceCoercionTy (toIfaceCoercionX fr co) + +toIfaceTypeX fr (TyConApp tc tys) + -- tuples + | Just sort <- tyConTuple_maybe tc + , n_tys == arity + = IfaceTupleTy sort NotPromoted (toIfaceTcArgsX fr tc tys) + + | Just dc <- isPromotedDataCon_maybe tc + , isTupleDataCon dc + , n_tys == 2*arity + = IfaceTupleTy BoxedTuple IsPromoted (toIfaceTcArgsX fr tc (drop arity tys)) + + | tc `elem` [ eqPrimTyCon, eqReprPrimTyCon, heqTyCon ] + , (k1:k2:_) <- tys + = let info = IfaceTyConInfo NotPromoted sort + sort | k1 `eqType` k2 = IfaceEqualityTyCon + | otherwise = IfaceNormalTyCon + in IfaceTyConApp (IfaceTyCon (tyConName tc) info) (toIfaceTcArgsX fr tc tys) + + -- other applications + | otherwise + = IfaceTyConApp (toIfaceTyCon tc) (toIfaceTcArgsX fr tc tys) + where + arity = tyConArity tc + n_tys = length tys + +toIfaceTyVar :: TyVar -> FastString +toIfaceTyVar = occNameFS . getOccName + +toIfaceCoVar :: CoVar -> FastString +toIfaceCoVar = occNameFS . getOccName + +toIfaceForAllBndr :: TyCoVarBinder -> IfaceForAllBndr +toIfaceForAllBndr = toIfaceForAllBndrX emptyVarSet + +toIfaceForAllBndrX :: VarSet -> TyCoVarBinder -> IfaceForAllBndr +toIfaceForAllBndrX fr (Bndr v vis) = Bndr (toIfaceBndrX fr v) vis + +---------------- +toIfaceTyCon :: TyCon -> IfaceTyCon +toIfaceTyCon tc + = IfaceTyCon tc_name info + where + tc_name = tyConName tc + info = IfaceTyConInfo promoted sort + promoted | isPromotedDataCon tc = IsPromoted + | otherwise = NotPromoted + + tupleSort :: TyCon -> Maybe IfaceTyConSort + tupleSort tc' = + case tyConTuple_maybe tc' of + Just UnboxedTuple -> let arity = tyConArity tc' `div` 2 + in Just $ IfaceTupleTyCon arity UnboxedTuple + Just sort -> let arity = tyConArity tc' + in Just $ IfaceTupleTyCon arity sort + Nothing -> Nothing + + sort + | Just tsort <- tupleSort tc = tsort + + | Just dcon <- isPromotedDataCon_maybe tc + , let tc' = dataConTyCon dcon + , Just tsort <- tupleSort tc' = tsort + + | isUnboxedSumTyCon tc + , Just cons <- isDataSumTyCon_maybe tc = IfaceSumTyCon (length cons) + + | otherwise = IfaceNormalTyCon + + +toIfaceTyCon_name :: Name -> IfaceTyCon +toIfaceTyCon_name n = IfaceTyCon n info + where info = IfaceTyConInfo NotPromoted IfaceNormalTyCon + -- Used for the "rough-match" tycon stuff, + -- where pretty-printing is not an issue + +toIfaceTyLit :: TyLit -> IfaceTyLit +toIfaceTyLit (NumTyLit x) = IfaceNumTyLit x +toIfaceTyLit (StrTyLit x) = IfaceStrTyLit x + +---------------- +toIfaceCoercion :: Coercion -> IfaceCoercion +toIfaceCoercion = toIfaceCoercionX emptyVarSet + +toIfaceCoercionX :: VarSet -> Coercion -> IfaceCoercion +-- (toIfaceCoercionX free ty) +-- translates the tyvars in 'free' as IfaceFreeTyVars +toIfaceCoercionX fr co + = go co + where + go_mco MRefl = IfaceMRefl + go_mco (MCo co) = IfaceMCo $ go co + + go (Refl ty) = IfaceReflCo (toIfaceTypeX fr ty) + go (GRefl r ty mco) = IfaceGReflCo r (toIfaceTypeX fr ty) (go_mco mco) + go (CoVarCo cv) + -- See [TcTyVars in IfaceType] in GHC.Iface.Type + | cv `elemVarSet` fr = IfaceFreeCoVar cv + | otherwise = IfaceCoVarCo (toIfaceCoVar cv) + go (HoleCo h) = IfaceHoleCo (coHoleCoVar h) + + go (AppCo co1 co2) = IfaceAppCo (go co1) (go co2) + go (SymCo co) = IfaceSymCo (go co) + go (TransCo co1 co2) = IfaceTransCo (go co1) (go co2) + go (NthCo _r d co) = IfaceNthCo d (go co) + go (LRCo lr co) = IfaceLRCo lr (go co) + go (InstCo co arg) = IfaceInstCo (go co) (go arg) + go (KindCo c) = IfaceKindCo (go c) + go (SubCo co) = IfaceSubCo (go co) + go (AxiomRuleCo co cs) = IfaceAxiomRuleCo (coaxrName co) (map go cs) + go (AxiomInstCo c i cs) = IfaceAxiomInstCo (coAxiomName c) i (map go cs) + go (UnivCo p r t1 t2) = IfaceUnivCo (go_prov p) r + (toIfaceTypeX fr t1) + (toIfaceTypeX fr t2) + go (TyConAppCo r tc cos) + | tc `hasKey` funTyConKey + , [_,_,_,_] <- cos = pprPanic "toIfaceCoercion" (ppr co) + | otherwise = IfaceTyConAppCo r (toIfaceTyCon tc) (map go cos) + go (FunCo r co1 co2) = IfaceFunCo r (go co1) (go co2) + + go (ForAllCo tv k co) = IfaceForAllCo (toIfaceBndr tv) + (toIfaceCoercionX fr' k) + (toIfaceCoercionX fr' co) + where + fr' = fr `delVarSet` tv + + go_prov :: UnivCoProvenance -> IfaceUnivCoProv + go_prov UnsafeCoerceProv = IfaceUnsafeCoerceProv + go_prov (PhantomProv co) = IfacePhantomProv (go co) + go_prov (ProofIrrelProv co) = IfaceProofIrrelProv (go co) + go_prov (PluginProv str) = IfacePluginProv str + +toIfaceTcArgs :: TyCon -> [Type] -> IfaceAppArgs +toIfaceTcArgs = toIfaceTcArgsX emptyVarSet + +toIfaceTcArgsX :: VarSet -> TyCon -> [Type] -> IfaceAppArgs +toIfaceTcArgsX fr tc ty_args = toIfaceAppArgsX fr (tyConKind tc) ty_args + +toIfaceAppTyArgsX :: VarSet -> Type -> [Type] -> IfaceAppArgs +toIfaceAppTyArgsX fr ty ty_args = toIfaceAppArgsX fr (typeKind ty) ty_args + +toIfaceAppArgsX :: VarSet -> Kind -> [Type] -> IfaceAppArgs +-- See Note [Suppressing invisible arguments] in GHC.Iface.Type +-- We produce a result list of args describing visibility +-- The awkward case is +-- T :: forall k. * -> k +-- And consider +-- T (forall j. blah) * blib +-- Is 'blib' visible? It depends on the visibility flag on j, +-- so we have to substitute for k. Annoying! +toIfaceAppArgsX fr kind ty_args + = go (mkEmptyTCvSubst in_scope) kind ty_args + where + in_scope = mkInScopeSet (tyCoVarsOfTypes ty_args) + + go _ _ [] = IA_Nil + go env ty ts + | Just ty' <- coreView ty + = go env ty' ts + go env (ForAllTy (Bndr tv vis) res) (t:ts) + = IA_Arg t' vis ts' + where + t' = toIfaceTypeX fr t + ts' = go (extendTCvSubst env tv t) res ts + + go env (FunTy { ft_af = af, ft_res = res }) (t:ts) + = IA_Arg (toIfaceTypeX fr t) argf (go env res ts) + where + argf = case af of + VisArg -> Required + InvisArg -> Inferred + -- It's rare for a kind to have a constraint argument, but + -- it can happen. See Note [AnonTCB InvisArg] in TyCon. + + go env ty ts@(t1:ts1) + | not (isEmptyTCvSubst env) + = go (zapTCvSubst env) (substTy env ty) ts + -- See Note [Care with kind instantiation] in Type.hs + + | otherwise + = -- There's a kind error in the type we are trying to print + -- e.g. kind = k, ty_args = [Int] + -- This is probably a compiler bug, so we print a trace and + -- carry on as if it were FunTy. Without the test for + -- isEmptyTCvSubst we'd get an infinite loop (#15473) + WARN( True, ppr kind $$ ppr ty_args ) + IA_Arg (toIfaceTypeX fr t1) Required (go env ty ts1) + +tidyToIfaceType :: TidyEnv -> Type -> IfaceType +tidyToIfaceType env ty = toIfaceType (tidyType env ty) + +tidyToIfaceTcArgs :: TidyEnv -> TyCon -> [Type] -> IfaceAppArgs +tidyToIfaceTcArgs env tc tys = toIfaceTcArgs tc (tidyTypes env tys) + +tidyToIfaceContext :: TidyEnv -> ThetaType -> IfaceContext +tidyToIfaceContext env theta = map (tidyToIfaceType env) theta + +{- +************************************************************************ +* * + Conversion of pattern synonyms +* * +************************************************************************ +-} + +patSynToIfaceDecl :: PatSyn -> IfaceDecl +patSynToIfaceDecl ps + = IfacePatSyn { ifName = getName $ ps + , ifPatMatcher = to_if_pr (patSynMatcher ps) + , ifPatBuilder = fmap to_if_pr (patSynBuilder ps) + , ifPatIsInfix = patSynIsInfix ps + , ifPatUnivBndrs = map toIfaceForAllBndr univ_bndrs' + , ifPatExBndrs = map toIfaceForAllBndr ex_bndrs' + , ifPatProvCtxt = tidyToIfaceContext env2 prov_theta + , ifPatReqCtxt = tidyToIfaceContext env2 req_theta + , ifPatArgs = map (tidyToIfaceType env2) args + , ifPatTy = tidyToIfaceType env2 rhs_ty + , ifFieldLabels = (patSynFieldLabels ps) + } + where + (_univ_tvs, req_theta, _ex_tvs, prov_theta, args, rhs_ty) = patSynSig ps + univ_bndrs = patSynUnivTyVarBinders ps + ex_bndrs = patSynExTyVarBinders ps + (env1, univ_bndrs') = tidyTyCoVarBinders emptyTidyEnv univ_bndrs + (env2, ex_bndrs') = tidyTyCoVarBinders env1 ex_bndrs + to_if_pr (id, needs_dummy) = (idName id, needs_dummy) + +{- +************************************************************************ +* * + Conversion of other things +* * +************************************************************************ +-} + +toIfaceBang :: TidyEnv -> HsImplBang -> IfaceBang +toIfaceBang _ HsLazy = IfNoBang +toIfaceBang _ (HsUnpack Nothing) = IfUnpack +toIfaceBang env (HsUnpack (Just co)) = IfUnpackCo (toIfaceCoercion (tidyCo env co)) +toIfaceBang _ HsStrict = IfStrict + +toIfaceSrcBang :: HsSrcBang -> IfaceSrcBang +toIfaceSrcBang (HsSrcBang _ unpk bang) = IfSrcBang unpk bang + +toIfaceLetBndr :: Id -> IfaceLetBndr +toIfaceLetBndr id = IfLetBndr (occNameFS (getOccName id)) + (toIfaceType (idType id)) + (toIfaceIdInfo (idInfo id)) + (toIfaceJoinInfo (isJoinId_maybe id)) + -- Put into the interface file any IdInfo that CoreTidy.tidyLetBndr + -- has left on the Id. See Note [IdInfo on nested let-bindings] in GHC.Iface.Syntax + +toIfaceIdDetails :: IdDetails -> IfaceIdDetails +toIfaceIdDetails VanillaId = IfVanillaId +toIfaceIdDetails (DFunId {}) = IfDFunId +toIfaceIdDetails (RecSelId { sel_naughty = n + , sel_tycon = tc }) = + let iface = case tc of + RecSelData ty_con -> Left (toIfaceTyCon ty_con) + RecSelPatSyn pat_syn -> Right (patSynToIfaceDecl pat_syn) + in IfRecSelId iface n + + -- The remaining cases are all "implicit Ids" which don't + -- appear in interface files at all +toIfaceIdDetails other = pprTrace "toIfaceIdDetails" (ppr other) + IfVanillaId -- Unexpected; the other + +toIfaceIdInfo :: IdInfo -> IfaceIdInfo +toIfaceIdInfo id_info + = case catMaybes [arity_hsinfo, caf_hsinfo, strict_hsinfo, + inline_hsinfo, unfold_hsinfo, levity_hsinfo] of + [] -> NoInfo + infos -> HasInfo infos + -- NB: strictness and arity must appear in the list before unfolding + -- See GHC.IfaceToCore.tcUnfolding + where + ------------ Arity -------------- + arity_info = arityInfo id_info + arity_hsinfo | arity_info == 0 = Nothing + | otherwise = Just (HsArity arity_info) + + ------------ Caf Info -------------- + caf_info = cafInfo id_info + caf_hsinfo = case caf_info of + NoCafRefs -> Just HsNoCafRefs + _other -> Nothing + + ------------ Strictness -------------- + -- No point in explicitly exporting TopSig + sig_info = strictnessInfo id_info + strict_hsinfo | not (isTopSig sig_info) = Just (HsStrictness sig_info) + | otherwise = Nothing + + ------------ Unfolding -------------- + unfold_hsinfo = toIfUnfolding loop_breaker (unfoldingInfo id_info) + loop_breaker = isStrongLoopBreaker (occInfo id_info) + + ------------ Inline prag -------------- + inline_prag = inlinePragInfo id_info + inline_hsinfo | isDefaultInlinePragma inline_prag = Nothing + | otherwise = Just (HsInline inline_prag) + + ------------ Levity polymorphism ---------- + levity_hsinfo | isNeverLevPolyIdInfo id_info = Just HsLevity + | otherwise = Nothing + +toIfaceJoinInfo :: Maybe JoinArity -> IfaceJoinInfo +toIfaceJoinInfo (Just ar) = IfaceJoinPoint ar +toIfaceJoinInfo Nothing = IfaceNotJoinPoint + +-------------------------- +toIfUnfolding :: Bool -> Unfolding -> Maybe IfaceInfoItem +toIfUnfolding lb (CoreUnfolding { uf_tmpl = rhs + , uf_src = src + , uf_guidance = guidance }) + = Just $ HsUnfold lb $ + case src of + InlineStable + -> case guidance of + UnfWhen {ug_arity = arity, ug_unsat_ok = unsat_ok, ug_boring_ok = boring_ok } + -> IfInlineRule arity unsat_ok boring_ok if_rhs + _other -> IfCoreUnfold True if_rhs + InlineCompulsory -> IfCompulsory if_rhs + InlineRhs -> IfCoreUnfold False if_rhs + -- Yes, even if guidance is UnfNever, expose the unfolding + -- If we didn't want to expose the unfolding, GHC.Iface.Tidy would + -- have stuck in NoUnfolding. For supercompilation we want + -- to see that unfolding! + where + if_rhs = toIfaceExpr rhs + +toIfUnfolding lb (DFunUnfolding { df_bndrs = bndrs, df_args = args }) + = Just (HsUnfold lb (IfDFunUnfold (map toIfaceBndr bndrs) (map toIfaceExpr args))) + -- No need to serialise the data constructor; + -- we can recover it from the type of the dfun + +toIfUnfolding _ (OtherCon {}) = Nothing + -- The binding site of an Id doesn't have OtherCon, except perhaps + -- where we have called zapUnfolding; and that evald'ness info is + -- not needed by importing modules + +toIfUnfolding _ BootUnfolding = Nothing + -- Can't happen; we only have BootUnfolding for imported binders + +toIfUnfolding _ NoUnfolding = Nothing + +{- +************************************************************************ +* * + Conversion of expressions +* * +************************************************************************ +-} + +toIfaceExpr :: CoreExpr -> IfaceExpr +toIfaceExpr (Var v) = toIfaceVar v +toIfaceExpr (Lit l) = IfaceLit l +toIfaceExpr (Type ty) = IfaceType (toIfaceType ty) +toIfaceExpr (Coercion co) = IfaceCo (toIfaceCoercion co) +toIfaceExpr (Lam x b) = IfaceLam (toIfaceBndr x, toIfaceOneShot x) (toIfaceExpr b) +toIfaceExpr (App f a) = toIfaceApp f [a] +toIfaceExpr (Case s x ty as) + | null as = IfaceECase (toIfaceExpr s) (toIfaceType ty) + | otherwise = IfaceCase (toIfaceExpr s) (getOccFS x) (map toIfaceAlt as) +toIfaceExpr (Let b e) = IfaceLet (toIfaceBind b) (toIfaceExpr e) +toIfaceExpr (Cast e co) = IfaceCast (toIfaceExpr e) (toIfaceCoercion co) +toIfaceExpr (Tick t e) + | Just t' <- toIfaceTickish t = IfaceTick t' (toIfaceExpr e) + | otherwise = toIfaceExpr e + +toIfaceOneShot :: Id -> IfaceOneShot +toIfaceOneShot id | isId id + , OneShotLam <- oneShotInfo (idInfo id) + = IfaceOneShot + | otherwise + = IfaceNoOneShot + +--------------------- +toIfaceTickish :: Tickish Id -> Maybe IfaceTickish +toIfaceTickish (ProfNote cc tick push) = Just (IfaceSCC cc tick push) +toIfaceTickish (HpcTick modl ix) = Just (IfaceHpcTick modl ix) +toIfaceTickish (SourceNote src names) = Just (IfaceSource src names) +toIfaceTickish (Breakpoint {}) = Nothing + -- Ignore breakpoints, since they are relevant only to GHCi, and + -- should not be serialised (#8333) + +--------------------- +toIfaceBind :: Bind Id -> IfaceBinding +toIfaceBind (NonRec b r) = IfaceNonRec (toIfaceLetBndr b) (toIfaceExpr r) +toIfaceBind (Rec prs) = IfaceRec [(toIfaceLetBndr b, toIfaceExpr r) | (b,r) <- prs] + +--------------------- +toIfaceAlt :: (AltCon, [Var], CoreExpr) + -> (IfaceConAlt, [FastString], IfaceExpr) +toIfaceAlt (c,bs,r) = (toIfaceCon c, map getOccFS bs, toIfaceExpr r) + +--------------------- +toIfaceCon :: AltCon -> IfaceConAlt +toIfaceCon (DataAlt dc) = IfaceDataAlt (getName dc) +toIfaceCon (LitAlt l) = IfaceLitAlt l +toIfaceCon DEFAULT = IfaceDefault + +--------------------- +toIfaceApp :: Expr CoreBndr -> [Arg CoreBndr] -> IfaceExpr +toIfaceApp (App f a) as = toIfaceApp f (a:as) +toIfaceApp (Var v) as + = case isDataConWorkId_maybe v of + -- We convert the *worker* for tuples into IfaceTuples + Just dc | saturated + , Just tup_sort <- tyConTuple_maybe tc + -> IfaceTuple tup_sort tup_args + where + val_args = dropWhile isTypeArg as + saturated = val_args `lengthIs` idArity v + tup_args = map toIfaceExpr val_args + tc = dataConTyCon dc + + _ -> mkIfaceApps (toIfaceVar v) as + +toIfaceApp e as = mkIfaceApps (toIfaceExpr e) as + +mkIfaceApps :: IfaceExpr -> [CoreExpr] -> IfaceExpr +mkIfaceApps f as = foldl' (\f a -> IfaceApp f (toIfaceExpr a)) f as + +--------------------- +toIfaceVar :: Id -> IfaceExpr +toIfaceVar v + | isBootUnfolding (idUnfolding v) + = -- See Note [Inlining and hs-boot files] + IfaceApp (IfaceApp (IfaceExt noinlineIdName) + (IfaceType (toIfaceType (idType v)))) + (IfaceExt name) -- don't use mkIfaceApps, or infinite loop + + | Just fcall <- isFCallId_maybe v = IfaceFCall fcall (toIfaceType (idType v)) + -- Foreign calls have special syntax + + | isExternalName name = IfaceExt name + | otherwise = IfaceLcl (getOccFS name) + where name = idName v + + +{- Note [Inlining and hs-boot files] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Consider this example (#10083, #12789): + + ---------- RSR.hs-boot ------------ + module RSR where + data RSR + eqRSR :: RSR -> RSR -> Bool + + ---------- SR.hs ------------ + module SR where + import {-# SOURCE #-} RSR + data SR = MkSR RSR + eqSR (MkSR r1) (MkSR r2) = eqRSR r1 r2 + + ---------- RSR.hs ------------ + module RSR where + import SR + data RSR = MkRSR SR -- deriving( Eq ) + eqRSR (MkRSR s1) (MkRSR s2) = (eqSR s1 s2) + foo x y = not (eqRSR x y) + +When compiling RSR we get this code + + RSR.eqRSR :: RSR -> RSR -> Bool + RSR.eqRSR = \ (ds1 :: RSR.RSR) (ds2 :: RSR.RSR) -> + case ds1 of _ { RSR.MkRSR s1 -> + case ds2 of _ { RSR.MkRSR s2 -> + SR.eqSR s1 s2 }} + + RSR.foo :: RSR -> RSR -> Bool + RSR.foo = \ (x :: RSR) (y :: RSR) -> not (RSR.eqRSR x y) + +Now, when optimising foo: + Inline eqRSR (small, non-rec) + Inline eqSR (small, non-rec) +but the result of inlining eqSR from SR is another call to eqRSR, so +everything repeats. Neither eqSR nor eqRSR are (apparently) loop +breakers. + +Solution: in the unfolding of eqSR in SR.hi, replace `eqRSR` in SR +with `noinline eqRSR`, so that eqRSR doesn't get inlined. This means +that when GHC inlines `eqSR`, it will not also inline `eqRSR`, exactly +as would have been the case if `foo` had been defined in SR.hs (and +marked as a loop-breaker). + +But how do we arrange for this to happen? There are two ingredients: + + 1. When we serialize out unfoldings to IfaceExprs (toIfaceVar), + for every variable reference we see if we are referring to an + 'Id' that came from an hs-boot file. If so, we add a `noinline` + to the reference. + + 2. But how do we know if a reference came from an hs-boot file + or not? We could record this directly in the 'IdInfo', but + actually we deduce this by looking at the unfolding: 'Id's + that come from boot files are given a special unfolding + (upon typechecking) 'BootUnfolding' which say that there is + no unfolding, and the reason is because the 'Id' came from + a boot file. + +Here is a solution that doesn't work: when compiling RSR, +add a NOINLINE pragma to every function exported by the boot-file +for RSR (if it exists). Doing so makes the bootstrapped GHC itself +slower by 8% overall (on #9872a-d, and T1969: the reason +is that these NOINLINE'd functions now can't be profitably inlined +outside of the hs-boot loop. + +-} |