+++ /dev/null
-%
-% (c) The AQUA Project, Glasgow University, 1998
-%
-\section[StdIdInfo]{Standard unfoldings}
-
-This module contains definitions for the IdInfo for things that
-have a standard form, namely:
-
- * data constructors
- * record selectors
- * method and superclass selectors
- * primitive operations
-
-\begin{code}
-module MkId (
- mkDictFunId, mkDefaultMethodId,
- mkDictSelId,
-
- mkDataConIds,
- mkRecordSelId,
- mkPrimOpId, mkFCallId,
-
- mkReboxingAlt, mkNewTypeBody,
-
- -- And some particular Ids; see below for why they are wired in
- 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,
- realWorldStatePrimTy, addrPrimTy
- )
-import TysWiredIn ( charTy, mkListTy )
-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, dataConsStupidTheta
- )
-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, DataConIds(..), dataConTyVars,
- dataConFieldLabels, dataConRepArity, dataConResTys,
- dataConRepArgTys, dataConRepType,
- dataConSig, dataConStrictMarks, dataConExStricts,
- splitProductType, isVanillaDataCon, dataConFieldType,
- dataConInstOrigArgTys
- )
-import Id ( idType, mkGlobalId, mkVanillaGlobal, mkSysLocal,
- mkTemplateLocals, mkTemplateLocalsNum, mkExportedLocalId,
- mkTemplateLocal, idName
- )
-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, mkPrimOpIdUnique )
-import Maybes
-import PrelNames
-import Util ( dropList, isSingleton )
-import Outputable
-import FastString
-import ListSetOps ( assoc )
-\end{code}
-
-%************************************************************************
-%* *
-\subsection{Wired in Ids}
-%* *
-%************************************************************************
-
-\begin{code}
-wiredInIds
- = [ -- These error-y things are wired in because we don't yet have
- -- a way to express in an interface file that the result type variable
- -- is 'open'; that is can be unified with an unboxed type
- --
- -- [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]
-
- 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}
-
-%************************************************************************
-%* *
-\subsection{Data constructors}
-%* *
-%************************************************************************
-
-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.
-
-We're going to build a constructor that looks like:
-
- data (Data a, C b) => T a b = T1 !a !Int b
-
- T1 = /\ a b ->
- \d1::Data a, d2::C b ->
- \p q r -> case p of { p ->
- case q of { q ->
- Con T1 [a,b] [p,q,r]}}
-
-Notice that
-
-* d2 is thrown away --- a context in a data decl is used to make sure
- one *could* construct dictionaries at the site the constructor
- is used, but the dictionary isn't actually used.
-
-* We have to check that we can construct Data dictionaries for
- the types a and Int. Once we've done that we can throw d1 away too.
-
-* We use (case p of q -> ...) to evaluate p, rather than "seq" because
- all that matters is that the arguments are evaluated. "seq" is
- very careful to preserve evaluation order, which we don't need
- to be here.
-
- You might think that we could simply give constructors some strictness
- info, like PrimOps, and let CoreToStg do the let-to-case transformation.
- But we don't do that because in the case of primops and functions strictness
- is a *property* not a *requirement*. In the case of constructors we need to
- do something active to evaluate the argument.
-
- Making an explicit case expression allows the simplifier to eliminate
- it in the (common) case where the constructor arg is already evaluated.
-
-
-\begin{code}
-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
- (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.
- -- 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
- -> (Int -> [Id] -> CoreExpr) -- Body
- -> Int -- Next rep arg id
- -> [Id] -- Rep args so far, reversed
- -> CoreExpr
- mk_case (arg,strict) body i rep_args
- = case strict of
- NotMarkedStrict -> body i (arg:rep_args)
- MarkedStrict
- | isUnLiftedType (idType arg) -> body i (arg:rep_args)
- | otherwise ->
- 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 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}
-
-
-%************************************************************************
-%* *
-\subsection{Record selectors}
-%* *
-%************************************************************************
-
-We're going to build a record selector unfolding that looks like this:
-
- data T a b c = T1 { ..., op :: a, ...}
- | T2 { ..., op :: a, ...}
- | T3
-
- sel = /\ a b c -> \ d -> case d of
- T1 ... x ... -> x
- T2 ... x ... -> x
- other -> error "..."
-
-Similarly for newtypes
-
- newtype N a = MkN { unN :: a->a }
-
- unN :: N a -> a -> a
- unN n = coerce (a->a) n
-
-We need to take a little care if the field has a polymorphic type:
-
- data R = R { f :: forall a. a->a }
-
-Then we want
-
- f :: forall a. R -> a -> a
- f = /\ a \ r = case r of
- R f -> f a
-
-(not f :: R -> forall a. a->a, which gives the type inference mechanism
-problems at call sites)
-
-Similarly for (recursive) newtypes
-
- newtype N = MkN { unN :: forall a. a->a }
-
- 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}
-
--- 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
- | is_naughty = naughty_id
- | otherwise = sel_id
- where
- 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 = 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
- -- data R = R { op :: forall a. Foo a => a -> a }
- -- Then we can't give op the type
- -- op :: R -> forall a. Foo a => a -> a
- -- because the typechecker doesn't understand foralls to the
- -- right of an arrow. The "right" type to give it is
- -- op :: forall a. Foo a => R -> a -> a
- -- But then we must generate the right unfolding too:
- -- op = /\a -> \dfoo -> \ r ->
- -- case r of
- -- R op -> op a dfoo
- -- Note that this is exactly the type we'd infer from a user defn
- -- op (R op) = op
-
- selector_ty :: Type
- selector_ty = mkForAllTys tyvars $ mkForAllTys field_tyvars $
- mkFunTys stupid_dict_tys $ mkFunTys field_dict_tys $
- mkFunTy data_ty field_tau
-
- arity = 1 + n_stupid_dicts + n_field_dict_tys
-
- (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 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!
- 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
-
- default_alt | no_default = []
- | otherwise = [(DEFAULT, [], error_expr)]
-
- -- 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 stupid_dict_ids $ mkLams field_dict_ids $
- Lam data_id $ sel_body
-
- 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])
-
-
--- (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)
---
--- mkDataAlt should really be in DataCon, but it can't because
--- it manipulates CoreSyn.
-
-mkReboxingAlt
- :: [Unique] -- Uniques for the new Ids
- -> DataCon
- -> [Var] -- Source-level args, including existential dicts
- -> CoreExpr -- RHS
- -> CoreAlt
-
-mkReboxingAlt us con args rhs
- | not (any isMarkedUnboxed stricts)
- = (DataAlt con, args, rhs)
-
- | otherwise
- = let
- (binds, args') = go args stricts us
- in
- (DataAlt con, args', mkLets binds rhs)
-
- 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}
-
-
-%************************************************************************
-%* *
-\subsection{Dictionary selectors}
-%* *
-%************************************************************************
-
-Selecting a field for a dictionary. If there is just one field, then
-there's nothing to do.
-
-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 (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
- -- C a -> C a
- -- for a single-op class (after all, the selector is the identity)
- -- But it's type must expose the representation of the dictionary
- -- to gat (say) C a -> (a -> a)
-
- info = noCafIdInfo
- `setArityInfo` 1
- `setUnfoldingInfo` mkTopUnfolding rhs
- `setAllStrictnessInfo` Just strict_sig
-
- -- We no longer use 'must-inline' on record selectors. They'll
- -- inline like crazy if they scrutinise a constructor
-
- -- 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
- 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 (mkTyVarTys tyvars)
- (dict_id:arg_ids) = mkTemplateLocals (mkPredTy pred : arg_tys)
-
- rhs | isNewTyCon tycon = mkLams tyvars $ Lam dict_id $
- mkNewTypeBody tycon (head arg_tys) (Var dict_id)
- | otherwise = mkLams tyvars $ Lam 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_expr
- -- Adds a coerce where necessary
- -- Used for both wrapping and unwrapping
- | isRecursiveTyCon tycon -- Recursive case; use a coerce
- = Note (Coerce result_ty (exprType result_expr)) result_expr
- | otherwise -- Normal case
- = result_expr
-\end{code}
-
-
-%************************************************************************
-%* *
-\subsection{Primitive operations
-%* *
-%************************************************************************
-
-\begin{code}
-mkPrimOpId :: PrimOp -> Id
-mkPrimOpId prim_op
- = id
- where
- (tyvars,arg_tys,res_ty, arity, strict_sig) = primOpSig prim_op
- ty = mkForAllTys tyvars (mkFunTys arg_tys res_ty)
- name = mkWiredInName gHC_PRIM (primOpOcc prim_op)
- (mkPrimOpIdUnique (primOpTag prim_op))
- Nothing (AnId id) UserSyntax
- id = mkGlobalId (PrimOpId prim_op) name ty info
-
- 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,
--- and a CCall structure that gives the correct details about calling
--- convention etc.
---
--- The *name* of this Id is a local name whose OccName gives the full
--- details of the ccall, type and all. This means that the interface
--- file reader can reconstruct a suitable Id
-
-mkFCallId :: Unique -> ForeignCall -> Type -> Id
-mkFCallId uniq fcall ty
- = ASSERT( isEmptyVarSet (tyVarsOfType ty) )
- -- A CCallOpId should have no free type variables;
- -- when doing substitutions won't substitute over it
- mkGlobalId (FCallId fcall) name ty info
- where
- 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 = noCafIdInfo
- `setArityInfo` arity
- `setAllStrictnessInfo` Just strict_sig
-
- (_, tau) = tcSplitForAllTys ty
- (arg_tys, _) = tcSplitFunTys tau
- arity = length arg_tys
- strict_sig = mkStrictSig (mkTopDmdType (replicate arity evalDmd) TopRes)
-\end{code}
-
-
-%************************************************************************
-%* *
-\subsection{DictFuns and default methods}
-%* *
-%************************************************************************
-
-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 = mkExportedLocalId dm_name ty
-
-mkDictFunId :: Name -- Name to use for the dict fun;
- -> [TyVar]
- -> ThetaType
- -> Class
- -> [Type]
- -> Id
-
-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)
-
-{- 1 dec 99: disable the Mark Jones optimisation for the sake
- of compatibility with Hugs.
- See `types/InstEnv' for a discussion related to this.
-
- (class_tyvars, sc_theta, _, _) = classBigSig clas
- not_const (clas, tys) = not (isEmptyVarSet (tyVarsOfTypes tys))
- 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
- -- expose the constant methods.
-
- other -> nub (inst_decl_theta ++ filter not_const sc_theta')
- -- Otherwise we pass the superclass dictionaries to
- -- the dictionary function; the Mark Jones optimisation.
- --
- -- NOTE the "nub". I got caught by this one:
- -- class Monad m => MonadT t m where ...
- -- instance Monad m => MonadT (EnvT env) m where ...
- -- Here, the inst_decl_theta has (Monad m); but so
- -- does the sc_theta'!
- --
- -- NOTE the "not_const". I got caught by this one too:
- -- class Foo a => Baz a b where ...
- -- instance Wob b => Baz T b where..
- -- Now sc_theta' has Foo T
--}
-\end{code}
-
-
-%************************************************************************
-%* *
-\subsection{Un-definable}
-%* *
-%************************************************************************
-
-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
-add it as a built-in Id with an unfolding here.
-
-The type variables we use here are "open" type variables: this means
-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 unsafeCoerceName ty info
- where
- info = noCafIdInfo `setUnfoldingInfo` mkCompulsoryUnfolding rhs
-
-
- ty = mkForAllTys [openAlphaTyVar,openBetaTyVar]
- (mkFunTy openAlphaTy openBetaTy)
- [x] = mkTemplateLocals [openAlphaTy]
- rhs = mkLams [openAlphaTyVar,openBetaTyVar,x] $
- Note (Coerce openBetaTy openAlphaTy) (Var x)
-
--- 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)
-
-seqId
- = pcMiscPrelId seqName ty info
- where
- info = noCafIdInfo `setUnfoldingInfo` mkCompulsoryUnfolding rhs
-
-
- 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)
-
-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 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}
-
-
-%************************************************************************
-%* *
-\subsection[PrelVals-error-related]{@error@ and friends; @trace@}
-%* *
-%************************************************************************
-
-GHC randomly injects these into the code.
-
-@patError@ is just a version of @error@ for pattern-matching
-failures. It knows various ``codes'' which expand to longer
-strings---this saves space!
-
-@absentErr@ is a thing we put in for ``absent'' arguments. They jolly
-well shouldn't be yanked on, but if one is, then you will get a
-friendly message from @absentErr@ (rather than a totally random
-crash).
-
-@parError@ is a special version of @error@ which the compiler does
-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}
-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}
-
-
-%************************************************************************
-%* *
-\subsection{Utilities}
-%* *
-%************************************************************************
-
-\begin{code}
-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 name ty
- = pcMiscPrelId name ty bottoming_info
- where
- 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
-\end{code}
-
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