X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FbasicTypes%2FMkId.lhs;h=84b3546e622f1b1f4421b6bc544caaca89a89b4a;hb=31751ccacc24ebe5d15a0af84b10dc612d455440;hp=761eef8248bde76d8ddd801bb9ae52df7159aa8e;hpb=729046306d0a028ebfc01d29006e3aa35e9d1bab;p=ghc-hetmet.git diff --git a/ghc/compiler/basicTypes/MkId.lhs b/ghc/compiler/basicTypes/MkId.lhs index 761eef8..84b3546 100644 --- a/ghc/compiler/basicTypes/MkId.lhs +++ b/ghc/compiler/basicTypes/MkId.lhs @@ -14,83 +14,84 @@ have a standard form, namely: \begin{code} module MkId ( mkDictFunId, mkDefaultMethodId, - mkDictSelId, + mkDictSelId, - mkDataConId, mkDataConWrapId, - mkRecordSelId, rebuildConArgs, + mkDataConIds, + mkRecordSelId, mkPrimOpId, mkFCallId, + mkReboxingAlt, mkNewTypeBody, + -- And some particular Ids; see below for why they are wired in - wiredInIds, - unsafeCoerceId, realWorldPrimId, - eRROR_ID, eRROR_CSTRING_ID, rEC_SEL_ERROR_ID, pAT_ERROR_ID, rEC_CON_ERROR_ID, - rEC_UPD_ERROR_ID, iRREFUT_PAT_ERROR_ID, nON_EXHAUSTIVE_GUARDS_ERROR_ID, - nO_METHOD_BINDING_ERROR_ID, aBSENT_ERROR_ID, pAR_ERROR_ID + wiredInIds, ghcPrimIds, + unsafeCoerceId, realWorldPrimId, voidArgId, nullAddrId, seqId, + lazyId, lazyIdUnfolding, lazyIdKey, + + mkRuntimeErrorApp, + rEC_CON_ERROR_ID, iRREFUT_PAT_ERROR_ID, rUNTIME_ERROR_ID, + nON_EXHAUSTIVE_GUARDS_ERROR_ID, nO_METHOD_BINDING_ERROR_ID, + pAT_ERROR_ID, eRROR_ID, + + unsafeCoerceName ) where #include "HsVersions.h" import BasicTypes ( Arity, StrictnessMark(..), isMarkedUnboxed, isMarkedStrict ) +import Rules ( mkSpecInfo ) import TysPrim ( openAlphaTyVars, alphaTyVar, alphaTy, - intPrimTy, realWorldStatePrimTy, addrPrimTy + realWorldStatePrimTy, addrPrimTy ) import TysWiredIn ( charTy, mkListTy ) -import PrelRules ( primOpRule ) -import Rules ( addRule ) -import TcType ( Type, ThetaType, mkDictTy, mkPredTys, mkTyConApp, - mkTyVarTys, mkClassPred, tcEqPred, +import PrelRules ( primOpRules ) +import Type ( TyThing(..), mkForAllTy, tyVarsOfTypes ) +import TcType ( Type, ThetaType, mkDictTy, mkPredTys, mkPredTy, + mkTyConApp, mkTyVarTys, mkClassPred, mkFunTys, mkFunTy, mkSigmaTy, tcSplitSigmaTy, isUnLiftedType, mkForAllTys, mkTyVarTy, tyVarsOfType, - tcSplitFunTys, tcSplitForAllTys, mkPredTy + tcSplitFunTys, tcSplitForAllTys, dataConsStupidTheta ) -import Module ( Module ) -import CoreUtils ( exprType, mkInlineMe ) -import CoreUnfold ( mkTopUnfolding, mkCompulsoryUnfolding, mkOtherCon ) -import Literal ( Literal(..) ) -import TyCon ( TyCon, isNewTyCon, tyConTyVars, tyConDataCons, - tyConTheta, isProductTyCon, isDataTyCon, isRecursiveTyCon ) -import Class ( Class, classTyCon, classTyVars, classSelIds ) -import Var ( Id, TyVar ) -import VarSet ( isEmptyVarSet ) -import Name ( mkWiredInName, mkFCallName, Name ) -import OccName ( mkVarOcc ) -import PrimOp ( PrimOp(DataToTagOp), primOpSig, mkPrimOpIdName ) +import CoreUtils ( exprType ) +import CoreUnfold ( mkTopUnfolding, mkCompulsoryUnfolding ) +import Literal ( nullAddrLit, mkStringLit ) +import TyCon ( TyCon, isNewTyCon, tyConDataCons, FieldLabel, + tyConStupidTheta, isProductTyCon, isDataTyCon, isRecursiveTyCon ) +import Class ( Class, classTyCon, classSelIds ) +import Var ( Id, TyVar, Var ) +import VarSet ( isEmptyVarSet, subVarSet, varSetElems ) +import Name ( mkFCallName, mkWiredInName, Name, BuiltInSyntax(..) ) +import OccName ( mkOccNameFS, varName ) +import PrimOp ( PrimOp, primOpSig, primOpOcc, primOpTag ) import ForeignCall ( ForeignCall ) -import DataCon ( DataCon, - dataConFieldLabels, dataConRepArity, dataConTyCon, - dataConArgTys, dataConRepType, dataConRepStrictness, - dataConInstOrigArgTys, - dataConName, dataConTheta, - dataConSig, dataConStrictMarks, dataConId, - splitProductType - ) -import Id ( idType, mkGlobalId, mkVanillaGlobal, mkSysLocal, - mkLocalIdWithInfo, setIdNoDiscard, - mkTemplateLocals, mkTemplateLocalsNum, - mkTemplateLocal, idNewStrictness, idName +import DataCon ( DataCon, DataConIds(..), dataConTyVars, + dataConFieldLabels, dataConRepArity, dataConResTys, + dataConRepArgTys, dataConRepType, + dataConSig, dataConStrictMarks, dataConExStricts, + splitProductType, isVanillaDataCon, dataConFieldType, + dataConInstOrigArgTys ) -import IdInfo ( IdInfo, noCafNoTyGenIdInfo, - exactArity, setUnfoldingInfo, setCprInfo, - setArityInfo, setSpecInfo, setCgInfo, - mkNewStrictnessInfo, setNewStrictnessInfo, - GlobalIdDetails(..), CafInfo(..), CprInfo(..), - CgInfo(..), setCgArity +import Id ( idType, mkGlobalId, mkVanillaGlobal, mkSysLocal, + mkTemplateLocals, mkTemplateLocalsNum, mkExportedLocalId, + mkTemplateLocal, idName ) -import NewDemand ( mkStrictSig, strictSigResInfo, DmdResult(..), - mkTopDmdType, topDmd, evalDmd ) -import FieldLabel ( mkFieldLabel, fieldLabelName, - firstFieldLabelTag, allFieldLabelTags, fieldLabelType +import IdInfo ( IdInfo, noCafIdInfo, setUnfoldingInfo, + setArityInfo, setSpecInfo, setCafInfo, + setAllStrictnessInfo, vanillaIdInfo, + GlobalIdDetails(..), CafInfo(..) ) +import NewDemand ( mkStrictSig, DmdResult(..), + mkTopDmdType, topDmd, evalDmd, lazyDmd, retCPR, + Demand(..), Demands(..) ) +import DmdAnal ( dmdAnalTopRhs ) import CoreSyn -import Unique ( mkBuiltinUnique ) +import Unique ( mkBuiltinUnique, mkPrimOpIdUnique ) import Maybes import PrelNames -import Maybe ( isJust ) +import Util ( dropList, isSingleton ) import Outputable -import ListSetOps ( assoc, assocMaybe ) -import UnicodeUtil ( stringToUtf8 ) -import Char ( ord ) +import FastString +import ListSetOps ( assoc ) \end{code} %************************************************************************ @@ -107,24 +108,33 @@ wiredInIds -- -- [The interface file format now carry such information, but there's -- no way yet of expressing at the definition site for these - -- error-reporting - -- functions that they have an 'open' result type. -- sof 1/99] - - aBSENT_ERROR_ID - , eRROR_ID - , eRROR_CSTRING_ID - , iRREFUT_PAT_ERROR_ID - , nON_EXHAUSTIVE_GUARDS_ERROR_ID - , nO_METHOD_BINDING_ERROR_ID - , pAR_ERROR_ID - , pAT_ERROR_ID - , rEC_CON_ERROR_ID - , rEC_UPD_ERROR_ID - - -- These three can't be defined in Haskell - , realWorldPrimId - , unsafeCoerceId - , getTagId + -- error-reporting functions that they have an 'open' + -- result type. -- sof 1/99] + + eRROR_ID, -- This one isn't used anywhere else in the compiler + -- But we still need it in wiredInIds so that when GHC + -- compiles a program that mentions 'error' we don't + -- import its type from the interface file; we just get + -- the Id defined here. Which has an 'open-tyvar' type. + + rUNTIME_ERROR_ID, + iRREFUT_PAT_ERROR_ID, + nON_EXHAUSTIVE_GUARDS_ERROR_ID, + nO_METHOD_BINDING_ERROR_ID, + pAT_ERROR_ID, + rEC_CON_ERROR_ID, + + lazyId + ] ++ ghcPrimIds + +-- These Ids are exported from GHC.Prim +ghcPrimIds + = [ -- These can't be defined in Haskell, but they have + -- perfectly reasonable unfoldings in Core + realWorldPrimId, + unsafeCoerceId, + nullAddrId, + seqId ] \end{code} @@ -134,43 +144,6 @@ wiredInIds %* * %************************************************************************ -\begin{code} -mkDataConId :: Name -> DataCon -> Id - -- Makes the *worker* for the data constructor; that is, the function - -- that takes the reprsentation arguments and builds the constructor. -mkDataConId work_name data_con - = id - where - id = mkGlobalId (DataConId data_con) work_name (dataConRepType data_con) info - info = noCafNoTyGenIdInfo - `setCgArity` arity - `setArityInfo` arity - `setNewStrictnessInfo` Just strict_sig - - arity = dataConRepArity data_con - strict_sig = mkStrictSig id arity (mkTopDmdType (dataConRepStrictness data_con) cpr_info) - - tycon = dataConTyCon data_con - cpr_info | isProductTyCon tycon && - isDataTyCon tycon && - arity > 0 && - arity <= mAX_CPR_SIZE = RetCPR - | otherwise = TopRes - -- RetCPR is only true for products that are real data types; - -- that is, not unboxed tuples or [non-recursive] newtypes - -mAX_CPR_SIZE :: Arity -mAX_CPR_SIZE = 10 --- We do not treat very big tuples as CPR-ish: --- a) for a start we get into trouble because there aren't --- "enough" unboxed tuple types (a tiresome restriction, --- but hard to fix), --- b) more importantly, big unboxed tuples get returned mainly --- on the stack, and are often then allocated in the heap --- by the caller. So doing CPR for them may in fact make --- things worse. -\end{code} - The wrapper for a constructor is an ordinary top-level binding that evaluates any strict args, unboxes any args that are going to be flattened, and calls the worker. @@ -208,87 +181,119 @@ Notice that Making an explicit case expression allows the simplifier to eliminate it in the (common) case where the constructor arg is already evaluated. + \begin{code} -mkDataConWrapId data_con - = wrap_id +mkDataConIds :: Name -> Name -> DataCon -> DataConIds + -- Makes the *worker* for the data constructor; that is, the function + -- that takes the reprsentation arguments and builds the constructor. +mkDataConIds wrap_name wkr_name data_con + | isNewTyCon tycon + = NewDC nt_wrap_id + + | any isMarkedStrict all_strict_marks -- Algebraic, needs wrapper + = AlgDC (Just alg_wrap_id) wrk_id + + | otherwise -- Algebraic, no wrapper + = AlgDC Nothing wrk_id where - wrap_id = mkGlobalId (DataConWrapId data_con) (dataConName data_con) wrap_ty info - work_id = dataConId data_con - - info = noCafNoTyGenIdInfo - `setUnfoldingInfo` mkTopUnfolding (mkInlineMe wrap_rhs) - `setCgArity` arity - -- The NoCaf-ness is set by noCafNoTyGenIdInfo - `setArityInfo` arity - -- It's important to specify the arity, so that partial - -- applications are treated as values - `setNewStrictnessInfo` Just wrap_sig - - wrap_ty = mkForAllTys all_tyvars $ - mkFunTys all_arg_tys - result_ty - - res_info = strictSigResInfo (idNewStrictness work_id) - wrap_sig = mkStrictSig wrap_id arity (mkTopDmdType (replicate arity topDmd) res_info) + (tyvars, theta, orig_arg_tys, tycon, res_tys) = dataConSig data_con + + dict_tys = mkPredTys theta + all_arg_tys = dict_tys ++ orig_arg_tys + result_ty = mkTyConApp tycon res_tys + + wrap_ty = mkForAllTys tyvars (mkFunTys all_arg_tys result_ty) + -- We used to include the stupid theta in the wrapper's args + -- but now we don't. Instead the type checker just injects these + -- extra constraints where necessary. + + ----------- Worker (algebraic data types only) -------------- + wrk_id = mkGlobalId (DataConWorkId data_con) wkr_name + (dataConRepType data_con) wkr_info + + wkr_arity = dataConRepArity data_con + wkr_info = noCafIdInfo + `setArityInfo` wkr_arity + `setAllStrictnessInfo` Just wkr_sig + `setUnfoldingInfo` evaldUnfolding -- Record that it's evaluated, + -- even if arity = 0 + + wkr_sig = mkStrictSig (mkTopDmdType (replicate wkr_arity topDmd) cpr_info) + -- Notice that we do *not* say the worker is strict + -- even if the data constructor is declared strict + -- e.g. data T = MkT !(Int,Int) + -- Why? Because the *wrapper* is strict (and its unfolding has case + -- expresssions that do the evals) but the *worker* itself is not. + -- If we pretend it is strict then when we see + -- case x of y -> $wMkT y + -- the simplifier thinks that y is "sure to be evaluated" (because + -- $wMkT is strict) and drops the case. No, $wMkT is not strict. + -- + -- When the simplifer sees a pattern + -- case e of MkT x -> ... + -- it uses the dataConRepStrictness of MkT to mark x as evaluated; + -- but that's fine... dataConRepStrictness comes from the data con + -- not from the worker Id. + + cpr_info | isProductTyCon tycon && + isDataTyCon tycon && + wkr_arity > 0 && + wkr_arity <= mAX_CPR_SIZE = retCPR + | otherwise = TopRes + -- RetCPR is only true for products that are real data types; + -- that is, not unboxed tuples or [non-recursive] newtypes + + ----------- Wrappers for newtypes -------------- + nt_wrap_id = mkGlobalId (DataConWrapId data_con) wrap_name wrap_ty nt_wrap_info + nt_wrap_info = noCafIdInfo -- The NoCaf-ness is set by noCafIdInfo + `setArityInfo` 1 -- Arity 1 + `setUnfoldingInfo` newtype_unf + newtype_unf = ASSERT( isVanillaDataCon data_con && + isSingleton orig_arg_tys ) + -- No existentials on a newtype, but it can have a context + -- e.g. newtype Eq a => T a = MkT (...) + mkTopUnfolding $ Note InlineMe $ + mkLams tyvars $ Lam id_arg1 $ + mkNewTypeBody tycon result_ty (Var id_arg1) + + id_arg1 = mkTemplateLocal 1 (head orig_arg_tys) + + ----------- Wrappers for algebraic data types -------------- + alg_wrap_id = mkGlobalId (DataConWrapId data_con) wrap_name wrap_ty alg_wrap_info + alg_wrap_info = noCafIdInfo -- The NoCaf-ness is set by noCafIdInfo + `setArityInfo` alg_arity + -- It's important to specify the arity, so that partial + -- applications are treated as values + `setUnfoldingInfo` alg_unf + `setAllStrictnessInfo` Just wrap_sig + + all_strict_marks = dataConExStricts data_con ++ dataConStrictMarks data_con + wrap_sig = mkStrictSig (mkTopDmdType arg_dmds cpr_info) + arg_dmds = map mk_dmd all_strict_marks + mk_dmd str | isMarkedStrict str = evalDmd + | otherwise = lazyDmd -- The Cpr info can be important inside INLINE rhss, where the - -- wrapper constructor isn't inlined - -- But we are sloppy about the argument demands, because we expect - -- to inline the constructor very vigorously. - - wrap_rhs | isNewTyCon tycon - = ASSERT( null ex_tyvars && null ex_dict_args && length orig_arg_tys == 1 ) - -- No existentials on a newtype, but it can have a context - -- e.g. newtype Eq a => T a = MkT (...) - mkLams tyvars $ mkLams dict_args $ Lam id_arg1 $ - mkNewTypeBody tycon result_ty id_arg1 - - | null dict_args && not (any isMarkedStrict strict_marks) - = Var work_id -- The common case. Not only is this efficient, - -- but it also ensures that the wrapper is replaced - -- by the worker even when there are no args. - -- f (:) x - -- becomes - -- f $w: x - -- This is really important in rule matching, - -- (We could match on the wrappers, - -- but that makes it less likely that rules will match - -- when we bring bits of unfoldings together.) - -- - -- NB: because of this special case, (map (:) ys) turns into - -- (map $w: ys), and thence into (map (\x xs. $w: x xs) ys) - -- in core-to-stg. The top-level defn for (:) is never used. - -- This is somewhat of a bore, but I'm currently leaving it - -- as is, so that there still is a top level curried (:) for - -- the interpreter to call. - - | otherwise - = mkLams all_tyvars $ mkLams dict_args $ - mkLams ex_dict_args $ mkLams id_args $ - foldr mk_case con_app - (zip (ex_dict_args++id_args) strict_marks) i3 [] - - con_app i rep_ids = mkApps (Var work_id) - (map varToCoreExpr (all_tyvars ++ reverse rep_ids)) - - (tyvars, theta, ex_tyvars, ex_theta, orig_arg_tys, tycon) = dataConSig data_con - all_tyvars = tyvars ++ ex_tyvars - - dict_tys = mkPredTys theta - ex_dict_tys = mkPredTys ex_theta - all_arg_tys = dict_tys ++ ex_dict_tys ++ orig_arg_tys - result_ty = mkTyConApp tycon (mkTyVarTys tyvars) - - mkLocals i tys = (zipWith mkTemplateLocal [i..i+n-1] tys, i+n) - where - n = length tys - - (dict_args, i1) = mkLocals 1 dict_tys - (ex_dict_args,i2) = mkLocals i1 ex_dict_tys - (id_args,i3) = mkLocals i2 orig_arg_tys - arity = i3-1 - (id_arg1:_) = id_args -- Used for newtype only - - strict_marks = dataConStrictMarks data_con + -- wrapper constructor isn't inlined. + -- And the argument strictness can be important too; we + -- may not inline a contructor when it is partially applied. + -- For example: + -- data W = C !Int !Int !Int + -- ...(let w = C x in ...(w p q)...)... + -- we want to see that w is strict in its two arguments + + alg_unf = mkTopUnfolding $ Note InlineMe $ + mkLams tyvars $ + mkLams dict_args $ mkLams id_args $ + foldr mk_case con_app + (zip (dict_args ++ id_args) all_strict_marks) + i3 [] + + con_app i rep_ids = mkApps (Var wrk_id) + (map varToCoreExpr (tyvars ++ reverse rep_ids)) + + (dict_args,i2) = mkLocals 1 dict_tys + (id_args,i3) = mkLocals i2 orig_arg_tys + alg_arity = i3-1 mk_case :: (Id, StrictnessMark) -- Arg, strictness @@ -302,15 +307,32 @@ mkDataConWrapId data_con MarkedStrict | isUnLiftedType (idType arg) -> body i (arg:rep_args) | otherwise -> - Case (Var arg) arg [(DEFAULT,[], body i (arg:rep_args))] + Case (Var arg) arg result_ty [(DEFAULT,[], body i (arg:rep_args))] MarkedUnboxed -> case splitProductType "do_unbox" (idType arg) of (tycon, tycon_args, con, tys) -> - Case (Var arg) arg [(DataAlt con, con_args, - body i' (reverse con_args ++ rep_args))] + Case (Var arg) arg result_ty + [(DataAlt con, + con_args, + body i' (reverse con_args ++ rep_args))] where (con_args, i') = mkLocals i tys + +mAX_CPR_SIZE :: Arity +mAX_CPR_SIZE = 10 +-- We do not treat very big tuples as CPR-ish: +-- a) for a start we get into trouble because there aren't +-- "enough" unboxed tuple types (a tiresome restriction, +-- but hard to fix), +-- b) more importantly, big unboxed tuples get returned mainly +-- on the stack, and are often then allocated in the heap +-- by the caller. So doing CPR for them may in fact make +-- things worse. + +mkLocals i tys = (zipWith mkTemplateLocal [i..i+n-1] tys, i+n) + where + n = length tys \end{code} @@ -351,39 +373,91 @@ Then we want (not f :: R -> forall a. a->a, which gives the type inference mechanism problems at call sites) -Similarly for newtypes +Similarly for (recursive) newtypes newtype N = MkN { unN :: forall a. a->a } - unN :: forall a. N -> a -> a - unN = /\a -> \n:N -> coerce (a->a) n + unN :: forall b. N -> b -> b + unN = /\b -> \n:N -> (coerce (forall a. a->a) n) + + +Note [Naughty record selectors] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +A "naughty" field is one for which we can't define a record +selector, because an existential type variable would escape. For example: + data T = forall a. MkT { x,y::a } +We obviously can't define + x (MkT v _) = v +Nevertheless we *do* put a RecordSelId into the type environment +so that if the user tries to use 'x' as a selector we can bleat +helpfully, rather than saying unhelpfully that 'x' is not in scope. +Hence the sel_naughty flag, to identify record selcectors that don't really exist. + +In general, a field is naughty if its type mentions a type variable that +isn't in the result type of the constructor. + +For GADTs, we require that all constructors with a common field 'f' have the same +result type (modulo alpha conversion). [Checked in TcTyClsDecls.checkValidTyCon] +E.g. + data T where + T1 { f :: a } :: T [a] + T2 { f :: a, y :: b } :: T [a] +and now the selector takes that type as its argument: + f :: forall a. T [a] -> a + f t = case t of + T1 { f = v } -> v + T2 { f = v } -> v +Note the forall'd tyvars of the selector are just the free tyvars +of the result type; there may be other tyvars in the constructor's +type (e.g. 'b' in T2). \begin{code} -mkRecordSelId tycon field_label unpack_id unpackUtf8_id + +-- XXX - autrijus - +-- Plan: 1. Determine naughtiness by comparing field type vs result type +-- 2. Install naughty ones with selector_ty of type _|_ and fill in mzero for info +-- 3. If it's not naughty, do the normal plan. + +mkRecordSelId :: TyCon -> FieldLabel -> Id +mkRecordSelId tycon field_label -- Assumes that all fields with the same field label have the same type - -- - -- Annoyingly, we have to pass in the unpackCString# Id, because - -- we can't conjure it up out of thin air - = sel_id + | is_naughty = naughty_id + | otherwise = sel_id where - sel_id = mkGlobalId (RecordSelId field_label) (fieldLabelName field_label) selector_ty info - field_ty = fieldLabelType field_label - data_cons = tyConDataCons tycon - tyvars = tyConTyVars tycon -- These scope over the types in - -- the FieldLabels of constructors of this type - data_ty = mkTyConApp tycon tyvar_tys - tyvar_tys = mkTyVarTys tyvars - - tycon_theta = tyConTheta tycon -- The context on the data decl - -- eg data (Eq a, Ord b) => T a b = ... - dict_tys = [mkPredTy pred | pred <- tycon_theta, - needed_dict pred] - needed_dict pred = or [ tcEqPred pred p - | (DataAlt dc, _, _) <- the_alts, p <- dataConTheta dc] - n_dict_tys = length dict_tys + is_naughty = not (tyVarsOfType field_ty `subVarSet` tyvar_set) + sel_id_details = RecordSelId tycon field_label is_naughty + + -- Escapist case here for naughty construcotrs + -- We give it no IdInfo, and a type of forall a.a (never looked at) + naughty_id = mkGlobalId sel_id_details field_label forall_a_a noCafIdInfo + forall_a_a = mkForAllTy alphaTyVar (mkTyVarTy alphaTyVar) + + -- Normal case starts here + sel_id = mkGlobalId sel_id_details field_label selector_ty info + data_cons = tyConDataCons tycon + data_cons_w_field = filter has_field data_cons -- Can't be empty! + has_field con = field_label `elem` dataConFieldLabels con + + con1 = head data_cons_w_field + res_tys = dataConResTys con1 + tyvar_set = tyVarsOfTypes res_tys + tyvars = varSetElems tyvar_set + data_ty = mkTyConApp tycon res_tys + field_ty = dataConFieldType con1 field_label + + -- *Very* tiresomely, the selectors are (unnecessarily!) overloaded over + -- just the dictionaries in the types of the constructors that contain + -- the relevant field. [The Report says that pattern matching on a + -- constructor gives the same constraints as applying it.] Urgh. + -- + -- However, not all data cons have all constraints (because of + -- BuildTyCl.mkDataConStupidTheta). So we need to find all the data cons + -- involved in the pattern match and take the union of their constraints. + stupid_dict_tys = mkPredTys (dataConsStupidTheta data_cons_w_field) + n_stupid_dicts = length stupid_dict_tys (field_tyvars,field_theta,field_tau) = tcSplitSigmaTy field_ty - field_dict_tys = map mkPredTy field_theta + field_dict_tys = mkPredTys field_theta n_field_dict_tys = length field_dict_tys -- If the field has a universally quantified type we have to -- be a bit careful. Suppose we have @@ -400,128 +474,146 @@ mkRecordSelId tycon field_label unpack_id unpackUtf8_id -- Note that this is exactly the type we'd infer from a user defn -- op (R op) = op - -- Very tiresomely, the selectors are (unnecessarily!) overloaded over - -- just the dictionaries in the types of the constructors that contain - -- the relevant field. Urgh. - -- NB: this code relies on the fact that DataCons are quantified over - -- the identical type variables as their parent TyCon - selector_ty :: Type selector_ty = mkForAllTys tyvars $ mkForAllTys field_tyvars $ - mkFunTys dict_tys $ mkFunTys field_dict_tys $ + mkFunTys stupid_dict_tys $ mkFunTys field_dict_tys $ mkFunTy data_ty field_tau - arity = 1 + n_dict_tys + n_field_dict_tys - info = noCafNoTyGenIdInfo - `setCgInfo` (CgInfo arity caf_info) - `setArityInfo` arity - `setUnfoldingInfo` unfolding - -- ToDo: consider adding further IdInfo + arity = 1 + n_stupid_dicts + n_field_dict_tys - unfolding = mkTopUnfolding sel_rhs + (strict_sig, rhs_w_str) = dmdAnalTopRhs sel_rhs + -- Use the demand analyser to work out strictness. + -- With all this unpackery it's not easy! + + info = noCafIdInfo + `setCafInfo` caf_info + `setArityInfo` arity + `setUnfoldingInfo` mkTopUnfolding rhs_w_str + `setAllStrictnessInfo` Just strict_sig -- Allocate Ids. We do it a funny way round because field_dict_tys is - -- almost always empty. Also note that we use length_tycon_theta + -- almost always empty. Also note that we use max_dict_tys -- rather than n_dict_tys, because the latter gives an infinite loop: -- n_dict tys depends on the_alts, which depens on arg_ids, which depends -- on arity, which depends on n_dict tys. Sigh! Mega sigh! - field_dict_base = length tycon_theta + 1 - dict_id_base = field_dict_base + n_field_dict_tys - field_base = dict_id_base + 1 - dict_ids = mkTemplateLocalsNum 1 dict_tys - field_dict_ids = mkTemplateLocalsNum field_dict_base field_dict_tys - data_id = mkTemplateLocal dict_id_base data_ty - - alts = map mk_maybe_alt data_cons - the_alts = catMaybes alts + stupid_dict_ids = mkTemplateLocalsNum 1 stupid_dict_tys + max_stupid_dicts = length (tyConStupidTheta tycon) + field_dict_base = max_stupid_dicts + 1 + field_dict_ids = mkTemplateLocalsNum field_dict_base field_dict_tys + dict_id_base = field_dict_base + n_field_dict_tys + data_id = mkTemplateLocal dict_id_base data_ty + arg_base = dict_id_base + 1 + + the_alts :: [CoreAlt] + the_alts = map mk_alt data_cons_w_field -- Already sorted by data-con + no_default = length data_cons == length data_cons_w_field -- No default needed - no_default = all isJust alts -- No default needed default_alt | no_default = [] | otherwise = [(DEFAULT, [], error_expr)] - -- the default branch may have CAF refs, because it calls recSelError etc. + -- The default branch may have CAF refs, because it calls recSelError etc. caf_info | no_default = NoCafRefs | otherwise = MayHaveCafRefs sel_rhs = mkLams tyvars $ mkLams field_tyvars $ - mkLams dict_ids $ mkLams field_dict_ids $ + mkLams stupid_dict_ids $ mkLams field_dict_ids $ Lam data_id $ sel_body - sel_body | isNewTyCon tycon = mkNewTypeBody tycon field_tau data_id - | otherwise = Case (Var data_id) data_id (default_alt ++ the_alts) - - mk_maybe_alt data_con - = case maybe_the_arg_id of - Nothing -> Nothing - Just the_arg_id -> Just (DataAlt data_con, real_args, mkLets binds body) - where - body = mkVarApps (mkVarApps (Var the_arg_id) field_tyvars) field_dict_ids - strict_marks = dataConStrictMarks data_con - (binds, real_args) = rebuildConArgs arg_ids strict_marks - (map mkBuiltinUnique [unpack_base..]) - where - arg_ids = mkTemplateLocalsNum field_base (dataConInstOrigArgTys data_con tyvar_tys) - - unpack_base = field_base + length arg_ids - - -- arity+1 avoids all shadowing - maybe_the_arg_id = assocMaybe (field_lbls `zip` arg_ids) field_label - field_lbls = dataConFieldLabels data_con - - error_expr = mkApps (Var rEC_SEL_ERROR_ID) [Type field_tau, err_string] - err_string - | all safeChar full_msg - = App (Var unpack_id) (Lit (MachStr (_PK_ full_msg))) - | otherwise - = App (Var unpackUtf8_id) (Lit (MachStr (_PK_ (stringToUtf8 (map ord full_msg))))) - where - safeChar c = c >= '\1' && c <= '\xFF' - -- TODO: Putting this Unicode stuff here is ugly. Find a better - -- generic place to make string literals. This logic is repeated - -- in DsUtils. - full_msg = showSDoc (sep [text "No match in record selector", ppr sel_id]) + sel_body | isNewTyCon tycon = mk_result (mkNewTypeBody tycon field_ty (Var data_id)) + | otherwise = Case (Var data_id) data_id field_tau (default_alt ++ the_alts) + mk_result poly_result = mkVarApps (mkVarApps poly_result field_tyvars) field_dict_ids + -- We pull the field lambdas to the top, so we need to + -- apply them in the body. For example: + -- data T = MkT { foo :: forall a. a->a } + -- + -- foo :: forall a. T -> a -> a + -- foo = /\a. \t:T. case t of { MkT f -> f a } + + mk_alt data_con + = -- In the non-vanilla case, the pattern must bind type variables and + -- the context stuff; hence the arg_prefix binding below + mkReboxingAlt uniqs data_con (arg_prefix ++ arg_ids) + (mk_result (Var the_arg_id)) + where + (arg_prefix, arg_ids) + | isVanillaDataCon data_con -- Instantiate from commmon base + = ([], mkTemplateLocalsNum arg_base (dataConInstOrigArgTys data_con res_tys)) + | otherwise -- The case pattern binds type variables, which are used + -- in the types of the arguments of the pattern + = (dc_tyvars ++ mkTemplateLocalsNum arg_base (mkPredTys dc_theta), + mkTemplateLocalsNum arg_base' dc_arg_tys) + + (dc_tyvars, dc_theta, dc_arg_tys, _, _) = dataConSig data_con + arg_base' = arg_base + length dc_theta + + unpack_base = arg_base' + length dc_arg_tys + uniqs = map mkBuiltinUnique [unpack_base..] + + the_arg_id = assoc "mkRecordSelId:mk_alt" (field_lbls `zip` arg_ids) field_label + field_lbls = dataConFieldLabels data_con + + error_expr = mkRuntimeErrorApp rEC_SEL_ERROR_ID field_tau full_msg + full_msg = showSDoc (sep [text "No match in record selector", ppr sel_id]) --- This rather ugly function converts the unpacked data con --- arguments back into their packed form. -rebuildConArgs - :: [Id] -- Source-level args - -> [StrictnessMark] -- Strictness annotations (per-arg) - -> [Unique] -- Uniques for the new Ids - -> ([CoreBind], [Id]) -- A binding for each source-level arg, plus - -- a list of the representation-level arguments --- e.g. data T = MkT Int !Int +-- (mkReboxingAlt us con xs rhs) basically constructs the case +-- alternative (con, xs, rhs) +-- but it does the reboxing necessary to construct the *source* +-- arguments, xs, from the representation arguments ys. +-- For example: +-- data T = MkT !(Int,Int) Bool +-- +-- mkReboxingAlt MkT [x,b] r +-- = (DataAlt MkT, [y::Int,z::Int,b], let x = (y,z) in r) -- --- rebuild [x::Int, y::Int] [Not, Unbox] --- = ([ y = I# t ], [x,t]) +-- mkDataAlt should really be in DataCon, but it can't because +-- it manipulates CoreSyn. -rebuildConArgs [] stricts us = ([], []) +mkReboxingAlt + :: [Unique] -- Uniques for the new Ids + -> DataCon + -> [Var] -- Source-level args, including existential dicts + -> CoreExpr -- RHS + -> CoreAlt --- Type variable case -rebuildConArgs (arg:args) stricts us - | isTyVar arg - = let (binds, args') = rebuildConArgs args stricts us - in (binds, arg:args') +mkReboxingAlt us con args rhs + | not (any isMarkedUnboxed stricts) + = (DataAlt con, args, rhs) --- Term variable case -rebuildConArgs (arg:args) (str:stricts) us - | isMarkedUnboxed str + | otherwise = let - arg_ty = idType arg - - (_, tycon_args, pack_con, con_arg_tys) - = splitProductType "rebuildConArgs" arg_ty - - unpacked_args = zipWith (mkSysLocal SLIT("rb")) us con_arg_tys - (binds, args') = rebuildConArgs args stricts (drop (length con_arg_tys) us) - con_app = mkConApp pack_con (map Type tycon_args ++ map Var unpacked_args) + (binds, args') = go args stricts us in - (NonRec arg con_app : binds, unpacked_args ++ args') + (DataAlt con, args', mkLets binds rhs) - | otherwise - = let (binds, args') = rebuildConArgs args stricts us - in (binds, arg:args') + where + stricts = dataConExStricts con ++ dataConStrictMarks con + + go [] stricts us = ([], []) + + -- Type variable case + go (arg:args) stricts us + | isTyVar arg + = let (binds, args') = go args stricts us + in (binds, arg:args') + + -- Term variable case + go (arg:args) (str:stricts) us + | isMarkedUnboxed str + = let + (_, tycon_args, pack_con, con_arg_tys) + = splitProductType "mkReboxingAlt" (idType arg) + + unpacked_args = zipWith (mkSysLocal FSLIT("rb")) us con_arg_tys + (binds, args') = go args stricts (dropList con_arg_tys us) + con_app = mkConApp pack_con (map Type tycon_args ++ map Var unpacked_args) + in + (NonRec arg con_app : binds, unpacked_args ++ args') + + | otherwise + = let (binds, args') = go args stricts us + in (binds, arg:args') \end{code} @@ -534,12 +626,25 @@ rebuildConArgs (arg:args) (str:stricts) us Selecting a field for a dictionary. If there is just one field, then there's nothing to do. -ToDo: unify with mkRecordSelId. +Dictionary selectors may get nested forall-types. Thus: + + class Foo a where + op :: forall b. Ord b => a -> b -> b + +Then the top-level type for op is + + op :: forall a. Foo a => + forall b. Ord b => + a -> b -> b + +This is unlike ordinary record selectors, which have all the for-alls +at the outside. When dealing with classes it's very convenient to +recover the original type signature from the class op selector. \begin{code} mkDictSelId :: Name -> Class -> Id mkDictSelId name clas - = mkGlobalId (RecordSelId field_lbl) name sel_ty info + = mkGlobalId (ClassOpId clas) name sel_ty info where sel_ty = mkForAllTys tyvars (mkFunTy (idType dict_id) (idType the_arg_id)) -- We can't just say (exprType rhs), because that would give a type @@ -548,41 +653,45 @@ mkDictSelId name clas -- But it's type must expose the representation of the dictionary -- to gat (say) C a -> (a -> a) - field_lbl = mkFieldLabel name tycon sel_ty tag - tag = assoc "MkId.mkDictSelId" (map idName (classSelIds clas) `zip` allFieldLabelTags) name + info = noCafIdInfo + `setArityInfo` 1 + `setUnfoldingInfo` mkTopUnfolding rhs + `setAllStrictnessInfo` Just strict_sig - info = noCafNoTyGenIdInfo - `setCgArity` 1 - `setArityInfo` 1 - `setUnfoldingInfo` unfolding - -- We no longer use 'must-inline' on record selectors. They'll -- inline like crazy if they scrutinise a constructor - unfolding = mkTopUnfolding rhs - - tyvars = classTyVars clas + -- The strictness signature is of the form U(AAAVAAAA) -> T + -- where the V depends on which item we are selecting + -- It's worth giving one, so that absence info etc is generated + -- even if the selector isn't inlined + strict_sig = mkStrictSig (mkTopDmdType [arg_dmd] TopRes) + arg_dmd | isNewTyCon tycon = evalDmd + | otherwise = Eval (Prod [ if the_arg_id == id then evalDmd else Abs + | id <- arg_ids ]) tycon = classTyCon clas [data_con] = tyConDataCons tycon - tyvar_tys = mkTyVarTys tyvars - arg_tys = dataConArgTys data_con tyvar_tys - the_arg_id = arg_ids !! (tag - firstFieldLabelTag) + tyvars = dataConTyVars data_con + arg_tys = dataConRepArgTys data_con + the_arg_id = assoc "MkId.mkDictSelId" (map idName (classSelIds clas) `zip` arg_ids) name - pred = mkClassPred clas tyvar_tys + pred = mkClassPred clas (mkTyVarTys tyvars) (dict_id:arg_ids) = mkTemplateLocals (mkPredTy pred : arg_tys) rhs | isNewTyCon tycon = mkLams tyvars $ Lam dict_id $ - mkNewTypeBody tycon (head arg_tys) dict_id + mkNewTypeBody tycon (head arg_tys) (Var dict_id) | otherwise = mkLams tyvars $ Lam dict_id $ - Case (Var dict_id) dict_id + Case (Var dict_id) dict_id (idType the_arg_id) [(DataAlt data_con, arg_ids, Var the_arg_id)] -mkNewTypeBody tycon result_ty result_id +mkNewTypeBody tycon result_ty result_expr + -- Adds a coerce where necessary + -- Used for both wrapping and unwrapping | isRecursiveTyCon tycon -- Recursive case; use a coerce - = Note (Coerce result_ty (idType result_id)) (Var result_id) + = Note (Coerce result_ty (exprType result_expr)) result_expr | otherwise -- Normal case - = Var result_id + = result_expr \end{code} @@ -597,21 +706,17 @@ mkPrimOpId :: PrimOp -> Id mkPrimOpId prim_op = id where - (tyvars,arg_tys,res_ty, arity, strict_info) = primOpSig prim_op + (tyvars,arg_tys,res_ty, arity, strict_sig) = primOpSig prim_op ty = mkForAllTys tyvars (mkFunTys arg_tys res_ty) - name = mkPrimOpIdName prim_op + name = mkWiredInName gHC_PRIM (primOpOcc prim_op) + (mkPrimOpIdUnique (primOpTag prim_op)) + Nothing (AnId id) UserSyntax id = mkGlobalId (PrimOpId prim_op) name ty info - info = noCafNoTyGenIdInfo - `setSpecInfo` rules - `setCgArity` arity - `setArityInfo` arity - `setNewStrictnessInfo` Just (mkNewStrictnessInfo id arity strict_info NoCPRInfo) - -- Until we modify the primop generation code - - rules = maybe emptyCoreRules (addRule emptyCoreRules id) - (primOpRule prim_op) - + info = noCafIdInfo + `setSpecInfo` mkSpecInfo (primOpRules prim_op name) + `setArityInfo` arity + `setAllStrictnessInfo` Just strict_sig -- For each ccall we manufacture a separate CCallOpId, giving it -- a fresh unique, a type that is correct for this particular ccall, @@ -627,24 +732,22 @@ mkFCallId uniq fcall ty = ASSERT( isEmptyVarSet (tyVarsOfType ty) ) -- A CCallOpId should have no free type variables; -- when doing substitutions won't substitute over it - id + mkGlobalId (FCallId fcall) name ty info where - id = mkGlobalId (FCallId fcall) name ty info - occ_str = showSDocIface (braces (ppr fcall <+> ppr ty)) + occ_str = showSDoc (braces (ppr fcall <+> ppr ty)) -- The "occurrence name" of a ccall is the full info about the -- ccall; it is encoded, but may have embedded spaces etc! name = mkFCallName uniq occ_str - info = noCafNoTyGenIdInfo - `setCgArity` arity + info = noCafIdInfo `setArityInfo` arity - `setNewStrictnessInfo` Just strict_sig + `setAllStrictnessInfo` Just strict_sig (_, tau) = tcSplitForAllTys ty (arg_tys, _) = tcSplitFunTys tau arity = length arg_tys - strict_sig = mkStrictSig id arity (mkTopDmdType (replicate arity evalDmd) TopRes) + strict_sig = mkStrictSig (mkTopDmdType (replicate arity evalDmd) TopRes) \end{code} @@ -654,31 +757,42 @@ mkFCallId uniq fcall ty %* * %************************************************************************ +Important notes about dict funs and default methods +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Dict funs and default methods are *not* ImplicitIds. Their definition +involves user-written code, so we can't figure out their strictness etc +based on fixed info, as we can for constructors and record selectors (say). + +We build them as LocalIds, but with External Names. This ensures that +they are taken to account by free-variable finding and dependency +analysis (e.g. CoreFVs.exprFreeVars). + +Why shouldn't they be bound as GlobalIds? Because, in particular, if +they are globals, the specialiser floats dict uses above their defns, +which prevents good simplifications happening. Also the strictness +analyser treats a occurrence of a GlobalId as imported and assumes it +contains strictness in its IdInfo, which isn't true if the thing is +bound in the same module as the occurrence. + +It's OK for dfuns to be LocalIds, because we form the instance-env to +pass on to the next module (md_insts) in CoreTidy, afer tidying +and globalising the top-level Ids. + +BUT make sure they are *exported* LocalIds (mkExportedLocalId) so +that they aren't discarded by the occurrence analyser. + \begin{code} -mkDefaultMethodId dm_name ty - = mkVanillaGlobal dm_name ty noCafNoTyGenIdInfo +mkDefaultMethodId dm_name ty = mkExportedLocalId dm_name ty mkDictFunId :: Name -- Name to use for the dict fun; - -> Class -> [TyVar] - -> [Type] -> ThetaType + -> Class + -> [Type] -> Id -mkDictFunId dfun_name clas inst_tyvars inst_tys dfun_theta - = setIdNoDiscard (mkLocalIdWithInfo dfun_name dfun_ty noCafNoTyGenIdInfo) - -- NB: It's important that dict funs are *local* Ids - -- This ensures that they are taken to account by free-variable finding - -- and dependency analysis (e.g. CoreFVs.exprFreeVars). - -- In particular, if they are globals, the - -- specialiser floats dict uses above their defns, which prevents - -- good simplifications happening. - -- - -- It's OK for them to be locals, because we form the instance-env to - -- pass on to the next module (md_insts) in CoreTidy, afer tdying - -- and globalising the top-level Ids. - -- - -- BUT Make sure it's an exported Id (setIdNoDiscard) so that it's not dropped! +mkDictFunId dfun_name inst_tyvars dfun_theta clas inst_tys + = mkExportedLocalId dfun_name dfun_ty where dfun_ty = mkSigmaTy inst_tyvars dfun_theta (mkDictTy clas inst_tys) @@ -688,7 +802,7 @@ mkDictFunId dfun_name clas inst_tyvars inst_tys dfun_theta (class_tyvars, sc_theta, _, _) = classBigSig clas not_const (clas, tys) = not (isEmptyVarSet (tyVarsOfTypes tys)) - sc_theta' = substClasses (mkTopTyVarSubst class_tyvars inst_tys) sc_theta + sc_theta' = substClasses (zipTopTvSubst class_tyvars inst_tys) sc_theta dfun_theta = case inst_decl_theta of [] -> [] -- If inst_decl_theta is empty, then we don't -- want to have any dict arguments, so that we can @@ -718,7 +832,12 @@ mkDictFunId dfun_name clas inst_tyvars inst_tys dfun_theta %* * %************************************************************************ -These two can't be defined in Haskell. +These Ids can't be defined in Haskell. They could be defined in +unfoldings in the wired-in GHC.Prim interface file, but we'd have to +ensure that they were definitely, definitely inlined, because there is +no curried identifier for them. That's what mkCompulsoryUnfolding +does. If we had a way to get a compulsory unfolding from an interface +file, we could do that, but we don't right now. unsafeCoerce# isn't so much a PrimOp as a phantom identifier, that just gets expanded into a type coercion wherever it occurs. Hence we @@ -729,10 +848,34 @@ they can unify with both unlifted and lifted types. Hence we provide another gun with which to shoot yourself in the foot. \begin{code} +mkWiredInIdName mod fs uniq id + = mkWiredInName mod (mkOccNameFS varName fs) uniq Nothing (AnId id) UserSyntax + +unsafeCoerceName = mkWiredInIdName gHC_PRIM FSLIT("unsafeCoerce#") unsafeCoerceIdKey unsafeCoerceId +nullAddrName = mkWiredInIdName gHC_PRIM FSLIT("nullAddr#") nullAddrIdKey nullAddrId +seqName = mkWiredInIdName gHC_PRIM FSLIT("seq") seqIdKey seqId +realWorldName = mkWiredInIdName gHC_PRIM FSLIT("realWorld#") realWorldPrimIdKey realWorldPrimId +lazyIdName = mkWiredInIdName pREL_BASE FSLIT("lazy") lazyIdKey lazyId + +errorName = mkWiredInIdName pREL_ERR FSLIT("error") errorIdKey eRROR_ID +recSelErrorName = mkWiredInIdName pREL_ERR FSLIT("recSelError") recSelErrorIdKey rEC_SEL_ERROR_ID +runtimeErrorName = mkWiredInIdName pREL_ERR FSLIT("runtimeError") runtimeErrorIdKey rUNTIME_ERROR_ID +irrefutPatErrorName = mkWiredInIdName pREL_ERR FSLIT("irrefutPatError") irrefutPatErrorIdKey iRREFUT_PAT_ERROR_ID +recConErrorName = mkWiredInIdName pREL_ERR FSLIT("recConError") recConErrorIdKey rEC_CON_ERROR_ID +patErrorName = mkWiredInIdName pREL_ERR FSLIT("patError") patErrorIdKey pAT_ERROR_ID +noMethodBindingErrorName = mkWiredInIdName pREL_ERR FSLIT("noMethodBindingError") + noMethodBindingErrorIdKey nO_METHOD_BINDING_ERROR_ID +nonExhaustiveGuardsErrorName + = mkWiredInIdName pREL_ERR FSLIT("nonExhaustiveGuardsError") + nonExhaustiveGuardsErrorIdKey nON_EXHAUSTIVE_GUARDS_ERROR_ID +\end{code} + +\begin{code} +-- unsafeCoerce# :: forall a b. a -> b unsafeCoerceId - = pcMiscPrelId unsafeCoerceIdKey pREL_GHC SLIT("unsafeCoerce#") ty info + = pcMiscPrelId unsafeCoerceName ty info where - info = noCafNoTyGenIdInfo `setUnfoldingInfo` mkCompulsoryUnfolding rhs + info = noCafIdInfo `setUnfoldingInfo` mkCompulsoryUnfolding rhs ty = mkForAllTys [openAlphaTyVar,openBetaTyVar] @@ -740,39 +883,67 @@ unsafeCoerceId [x] = mkTemplateLocals [openAlphaTy] rhs = mkLams [openAlphaTyVar,openBetaTyVar,x] $ Note (Coerce openBetaTy openAlphaTy) (Var x) -\end{code} +-- nullAddr# :: Addr# +-- The reason is is here is because we don't provide +-- a way to write this literal in Haskell. +nullAddrId + = pcMiscPrelId nullAddrName addrPrimTy info + where + info = noCafIdInfo `setUnfoldingInfo` + mkCompulsoryUnfolding (Lit nullAddrLit) -@getTag#@ is another function which can't be defined in Haskell. It needs to -evaluate its argument and call the dataToTag# primitive. - -\begin{code} -getTagId - = pcMiscPrelId getTagIdKey pREL_GHC SLIT("getTag#") ty info +seqId + = pcMiscPrelId seqName ty info where - info = noCafNoTyGenIdInfo `setUnfoldingInfo` mkCompulsoryUnfolding rhs - -- We don't provide a defn for this; you must inline it + info = noCafIdInfo `setUnfoldingInfo` mkCompulsoryUnfolding rhs + - ty = mkForAllTys [alphaTyVar] (mkFunTy alphaTy intPrimTy) - [x,y] = mkTemplateLocals [alphaTy,alphaTy] - rhs = mkLams [alphaTyVar,x] $ - Case (Var x) y [ (DEFAULT, [], mkApps (Var dataToTagId) [Type alphaTy, Var y]) ] + ty = mkForAllTys [alphaTyVar,openBetaTyVar] + (mkFunTy alphaTy (mkFunTy openBetaTy openBetaTy)) + [x,y] = mkTemplateLocals [alphaTy, openBetaTy] +-- gaw 2004 + rhs = mkLams [alphaTyVar,openBetaTyVar,x,y] (Case (Var x) x openBetaTy [(DEFAULT, [], Var y)]) + +-- lazy :: forall a?. a? -> a? (i.e. works for unboxed types too) +-- Used to lazify pseq: pseq a b = a `seq` lazy b +-- No unfolding: it gets "inlined" by the worker/wrapper pass +-- Also, no strictness: by being a built-in Id, it overrides all +-- the info in PrelBase.hi. This is important, because the strictness +-- analyser will spot it as strict! +lazyId + = pcMiscPrelId lazyIdName ty info + where + info = noCafIdInfo + ty = mkForAllTys [alphaTyVar] (mkFunTy alphaTy alphaTy) -dataToTagId = mkPrimOpId DataToTagOp +lazyIdUnfolding :: CoreExpr -- Used to expand LazyOp after strictness anal +lazyIdUnfolding = mkLams [openAlphaTyVar,x] (Var x) + where + [x] = mkTemplateLocals [openAlphaTy] \end{code} @realWorld#@ used to be a magic literal, \tr{void#}. If things get nasty as-is, change it back to a literal (@Literal@). +voidArgId is a Local Id used simply as an argument in functions +where we just want an arg to avoid having a thunk of unlifted type. +E.g. + x = \ void :: State# RealWorld -> (# p, q #) + +This comes up in strictness analysis + \begin{code} realWorldPrimId -- :: State# RealWorld - = pcMiscPrelId realWorldPrimIdKey pREL_GHC SLIT("realWorld#") - realWorldStatePrimTy - (noCafNoTyGenIdInfo `setUnfoldingInfo` mkOtherCon []) - -- The mkOtherCon makes it look that realWorld# is evaluated + = pcMiscPrelId realWorldName realWorldStatePrimTy + (noCafIdInfo `setUnfoldingInfo` evaldUnfolding) + -- The evaldUnfolding makes it look that realWorld# is evaluated -- which in turn makes Simplify.interestingArg return True, -- which in turn makes INLINE things applied to realWorld# likely -- to be inlined + +voidArgId -- :: State# RealWorld + = mkSysLocal FSLIT("void") voidArgIdKey realWorldStatePrimTy \end{code} @@ -798,33 +969,39 @@ not know to be a bottoming Id. It is used in the @_par_@ and @_seq_@ templates, but we don't ever expect to generate code for it. \begin{code} -eRROR_ID - = pc_bottoming_Id errorIdKey pREL_ERR SLIT("error") errorTy -eRROR_CSTRING_ID - = pc_bottoming_Id errorCStringIdKey pREL_ERR SLIT("errorCString") - (mkSigmaTy [openAlphaTyVar] [] (mkFunTy addrPrimTy openAlphaTy)) -pAT_ERROR_ID - = generic_ERROR_ID patErrorIdKey SLIT("patError") -rEC_SEL_ERROR_ID - = generic_ERROR_ID recSelErrIdKey SLIT("recSelError") -rEC_CON_ERROR_ID - = generic_ERROR_ID recConErrorIdKey SLIT("recConError") -rEC_UPD_ERROR_ID - = generic_ERROR_ID recUpdErrorIdKey SLIT("recUpdError") -iRREFUT_PAT_ERROR_ID - = generic_ERROR_ID irrefutPatErrorIdKey SLIT("irrefutPatError") -nON_EXHAUSTIVE_GUARDS_ERROR_ID - = generic_ERROR_ID nonExhaustiveGuardsErrorIdKey SLIT("nonExhaustiveGuardsError") -nO_METHOD_BINDING_ERROR_ID - = generic_ERROR_ID noMethodBindingErrorIdKey SLIT("noMethodBindingError") - -aBSENT_ERROR_ID - = pc_bottoming_Id absentErrorIdKey pREL_ERR SLIT("absentErr") - (mkSigmaTy [openAlphaTyVar] [] openAlphaTy) - -pAR_ERROR_ID - = pcMiscPrelId parErrorIdKey pREL_ERR SLIT("parError") - (mkSigmaTy [openAlphaTyVar] [] openAlphaTy) noCafNoTyGenIdInfo +mkRuntimeErrorApp + :: Id -- Should be of type (forall a. Addr# -> a) + -- where Addr# points to a UTF8 encoded string + -> Type -- The type to instantiate 'a' + -> String -- The string to print + -> CoreExpr + +mkRuntimeErrorApp err_id res_ty err_msg + = mkApps (Var err_id) [Type res_ty, err_string] + where + err_string = Lit (mkStringLit err_msg) + +rEC_SEL_ERROR_ID = mkRuntimeErrorId recSelErrorName +rUNTIME_ERROR_ID = mkRuntimeErrorId runtimeErrorName +iRREFUT_PAT_ERROR_ID = mkRuntimeErrorId irrefutPatErrorName +rEC_CON_ERROR_ID = mkRuntimeErrorId recConErrorName +pAT_ERROR_ID = mkRuntimeErrorId patErrorName +nO_METHOD_BINDING_ERROR_ID = mkRuntimeErrorId noMethodBindingErrorName +nON_EXHAUSTIVE_GUARDS_ERROR_ID = mkRuntimeErrorId nonExhaustiveGuardsErrorName + +-- The runtime error Ids take a UTF8-encoded string as argument +mkRuntimeErrorId name = pc_bottoming_Id name runtimeErrorTy +runtimeErrorTy = mkSigmaTy [openAlphaTyVar] [] (mkFunTy addrPrimTy openAlphaTy) +\end{code} + +\begin{code} +eRROR_ID = pc_bottoming_Id errorName errorTy + +errorTy :: Type +errorTy = mkSigmaTy [openAlphaTyVar] [] (mkFunTys [mkListTy charTy] openAlphaTy) + -- Notice the openAlphaTyVar. It says that "error" can be applied + -- to unboxed as well as boxed types. This is OK because it never + -- returns, so the return type is irrelevant. \end{code} @@ -835,39 +1012,33 @@ pAR_ERROR_ID %************************************************************************ \begin{code} -pcMiscPrelId :: Unique{-IdKey-} -> Module -> FAST_STRING -> Type -> IdInfo -> Id -pcMiscPrelId key mod str ty info - = let - name = mkWiredInName mod (mkVarOcc str) key - imp = mkVanillaGlobal name ty info -- the usual case... - in - imp +pcMiscPrelId :: Name -> Type -> IdInfo -> Id +pcMiscPrelId name ty info + = mkVanillaGlobal name ty info -- We lie and say the thing is imported; otherwise, we get into -- a mess with dependency analysis; e.g., core2stg may heave in -- random calls to GHCbase.unpackPS__. If GHCbase is the module -- being compiled, then it's just a matter of luck if the definition -- will be in "the right place" to be in scope. -pc_bottoming_Id key mod name ty - = id +pc_bottoming_Id name ty + = pcMiscPrelId name ty bottoming_info where - id = pcMiscPrelId key mod name ty bottoming_info - arity = 1 - strict_sig = mkStrictSig id arity (mkTopDmdType [evalDmd] BotRes) - bottoming_info = noCafNoTyGenIdInfo `setNewStrictnessInfo` Just strict_sig - -- these "bottom" out, no matter what their arguments - -generic_ERROR_ID u n = pc_bottoming_Id u pREL_ERR n errorTy + bottoming_info = vanillaIdInfo `setAllStrictnessInfo` Just strict_sig + -- Do *not* mark them as NoCafRefs, because they can indeed have + -- CAF refs. For example, pAT_ERROR_ID calls GHC.Err.untangle, + -- which has some CAFs + -- In due course we may arrange that these error-y things are + -- regarded by the GC as permanently live, in which case we + -- can give them NoCaf info. As it is, any function that calls + -- any pc_bottoming_Id will itself have CafRefs, which bloats + -- SRTs. + + strict_sig = mkStrictSig (mkTopDmdType [evalDmd] BotRes) + -- These "bottom" out, no matter what their arguments (openAlphaTyVar:openBetaTyVar:_) = openAlphaTyVars openAlphaTy = mkTyVarTy openAlphaTyVar openBetaTy = mkTyVarTy openBetaTyVar - -errorTy :: Type -errorTy = mkSigmaTy [openAlphaTyVar] [] (mkFunTys [mkListTy charTy] - openAlphaTy) - -- Notice the openAlphaTyVar. It says that "error" can be applied - -- to unboxed as well as boxed types. This is OK because it never - -- returns, so the return type is irrelevant. \end{code}