- primitive operations
\begin{code}
-{-# OPTIONS -fno-warn-missing-signatures #-}
--- The above warning supression flag is a temporary kludge.
--- While working on this module you are encouraged to remove it and fix
--- any warnings in the module. See
--- <http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings>
--- for details
-
module MkId (
- mkDictFunId, mkDefaultMethodId,
- mkDictSelId,
+ mkDictFunId, mkDictFunTy, mkDefaultMethodId, mkDictSelId,
mkDataConIds,
mkPrimOpId, mkFCallId, mkTickBoxOpId, mkBreakPointOpId,
-- And some particular Ids; see below for why they are wired in
wiredInIds, ghcPrimIds,
- unsafeCoerceId, realWorldPrimId, voidArgId, nullAddrId, seqId,
- lazyId, lazyIdKey,
-
- mkRuntimeErrorApp, mkImpossibleExpr,
- 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, rEC_SEL_ERROR_ID,
-
- unsafeCoerceName
+ unsafeCoerceName, unsafeCoerceId, realWorldPrimId,
+ voidArgId, nullAddrId, seqId, lazyId, lazyIdKey
) where
#include "HsVersions.h"
import Rules
import TysPrim
-import TysWiredIn
import PrelRules
import Type
import Coercion
import TcType
+import MkCore
import CoreUtils ( exprType, mkCoerce )
import CoreUnfold
import Literal
import Id
import Var ( Var, TyVar, mkCoVar, mkExportedLocalVar )
import IdInfo
-import NewDemand
+import Demand
import CoreSyn
import Unique
import PrelNames
\begin{code}
wiredInIds :: [Id]
wiredInIds
- = [
-
- 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,
- rEC_SEL_ERROR_ID,
-
- lazyId
- ] ++ ghcPrimIds
+ = [lazyId]
+ ++ errorIds -- Defined in MkCore
+ ++ ghcPrimIds
-- These Ids are exported from GHC.Prim
ghcPrimIds :: [Id]
data instance T [a] where
T1 :: forall b. b -> T [Maybe b]
-Hence
- Co7T a :: T [a] ~ :R7T a
-Now we want
+Hence we translate to
-- Wrapper
$WT1 :: forall b. b -> T [Maybe b]
-- Worker
T1 :: forall c b. (c ~ Maybe b) => b -> :R7T c
+ -- Coercion from family type to representation type
+ Co7T a :: T [a] ~ :R7T a
+
\begin{code}
mkDataConIds :: Name -> Name -> DataCon -> DataConIds
mkDataConIds wrap_name wkr_name data_con
| isNewTyCon tycon -- Newtype, only has a worker
= DCIds Nothing nt_work_id
- | any isMarkedStrict all_strict_marks -- Algebraic, needs wrapper
- || not (null eq_spec) -- NB: LoadIface.ifaceDeclSubBndrs
- || isFamInstTyCon tycon -- depends on this test
+ | any isBanged all_strict_marks -- Algebraic, needs wrapper
+ || not (null eq_spec) -- NB: LoadIface.ifaceDeclSubBndrs
+ || isFamInstTyCon tycon -- depends on this test
= DCIds (Just alg_wrap_id) wrk_id
| otherwise -- Algebraic, no wrapper
wkr_arity = dataConRepArity data_con
wkr_info = noCafIdInfo
`setArityInfo` wkr_arity
- `setAllStrictnessInfo` Just wkr_sig
+ `setStrictnessInfo` Just wkr_sig
`setUnfoldingInfo` evaldUnfolding -- Record that it's evaluated,
-- even if arity = 0
`setArityInfo` wrap_arity
-- It's important to specify the arity, so that partial
-- applications are treated as values
+ `setInlinePragInfo` alwaysInlinePragma
`setUnfoldingInfo` wrap_unf
- `setAllStrictnessInfo` Just wrap_sig
+ `setStrictnessInfo` 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
+ mk_dmd str | isBanged 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
-- ...(let w = C x in ...(w p q)...)...
-- we want to see that w is strict in its two arguments
- wrap_unf = mkInlineRule InlSat wrap_rhs (length dict_args + length id_args)
+ wrap_unf = mkInlineUnfolding (Just (length dict_args + length id_args)) wrap_rhs
wrap_rhs = mkLams wrap_tvs $
mkLams eq_args $
mkLams dict_args $ mkLams id_args $
mkCoVarLocals i [] = ([],i)
mkCoVarLocals i (x:xs) = let (ys,j) = mkCoVarLocals (i+1) xs
- y = mkCoVar (mkSysTvName (mkBuiltinUnique i) (fsLit "dc_co")) x
+ y = mkCoVar (mkSysTvName (mkBuiltinUnique i)
+ (fsLit "dc_co")) x
in (y:ys,j)
mk_case
- :: (Id, StrictnessMark) -- Arg, strictness
+ :: (Id, HsBang) -- 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 res_ty [(DEFAULT,[], body i (arg:rep_args))]
-
- MarkedUnboxed
- -> unboxProduct i (Var arg) (idType arg) the_body
+ HsNoBang -> body i (arg:rep_args)
+ HsUnpack -> unboxProduct i (Var arg) (idType arg) the_body
where
the_body i con_args = body i (reverse con_args ++ rep_args)
+ _other -- HsUnpackFailed and HsStrict
+ | isUnLiftedType (idType arg) -> body i (arg:rep_args)
+ | otherwise -> Case (Var arg) arg res_ty
+ [(DEFAULT,[], body i (arg:rep_args))]
mAX_CPR_SIZE :: Arity
mAX_CPR_SIZE = 10
-- by the caller. So doing CPR for them may in fact make
-- things worse.
+mkLocals :: Int -> [Type] -> ([Id], Int)
mkLocals i tys = (zipWith mkTemplateLocal [i..i+n-1] tys, i+n)
where
n = length tys
recover the original type signature from the class op selector.
\begin{code}
-mkDictSelId :: Bool -- True <=> don't include the unfolding
- -- Little point on imports without -O, because the
- -- dictionary itself won't be visible
- -> Name -> Class -> Id
+mkDictSelId :: Bool -- True <=> don't include the unfolding
+ -- Little point on imports without -O, because the
+ -- dictionary itself won't be visible
+ -> Name -- Name of one of the *value* selectors
+ -- (dictionary superclass or method)
+ -> Class -> Id
mkDictSelId no_unf name clas
= mkGlobalId (ClassOpId clas) name sel_ty info
where
-- But it's type must expose the representation of the dictionary
-- to get (say) C a -> (a -> a)
- info = noCafIdInfo
- `setArityInfo` 1
- `setAllStrictnessInfo` Just strict_sig
- `setSpecInfo` mkSpecInfo [rule]
- `setInlinePragInfo` neverInlinePragma
+ base_info = noCafIdInfo
+ `setArityInfo` 1
+ `setStrictnessInfo` Just strict_sig
`setUnfoldingInfo` (if no_unf then noUnfolding
- else mkImplicitUnfolding rhs)
- -- Experimental: NOINLINE, so that their rule matches
-
- -- We no longer use 'must-inline' on record selectors. They'll
- -- inline like crazy if they scrutinise a constructor
+ else mkImplicitUnfolding rhs)
+ -- In module where class op is defined, we must add
+ -- the unfolding, even though it'll never be inlined
+ -- becuase we use that to generate a top-level binding
+ -- for the ClassOp
+
+ info = base_info `setSpecInfo` mkSpecInfo [rule]
+ `setInlinePragInfo` neverInlinePragma
+ -- Add a magic BuiltinRule, and never inline it
+ -- so that the rule is always available to fire.
+ -- See Note [ClassOp/DFun selection] in TcInstDcls
n_ty_args = length tyvars
occNameFS (getOccName name)
, ru_fn = name
, ru_nargs = n_ty_args + 1
- , ru_try = dictSelRule index n_ty_args }
+ , ru_try = dictSelRule val_index n_ty_args n_eq_args }
-- 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 = dataConUnivTyVars data_con
- arg_tys = {- ASSERT( isVanillaDataCon data_con ) -} dataConRepArgTys data_con
- eq_theta = dataConEqTheta data_con
- index = assoc "MkId.mkDictSelId" (map idName (classSelIds clas) `zip` [0..]) name
- the_arg_id = arg_ids !! index
-
- pred = mkClassPred clas (mkTyVarTys tyvars)
- dict_id = mkTemplateLocal 1 $ mkPredTy pred
- (eq_ids,n) = mkCoVarLocals 2 $ mkPredTys eq_theta
- arg_ids = mkTemplateLocalsNum n arg_tys
-
- mkCoVarLocals i [] = ([],i)
- mkCoVarLocals i (x:xs) = let (ys,j) = mkCoVarLocals (i+1) xs
- y = mkCoVar (mkSysTvName (mkBuiltinUnique i) (fsLit "dc_co")) x
- in (y:ys,j)
+ arg_dmd | new_tycon = evalDmd
+ | otherwise = Eval (Prod [ if the_arg_id == id then evalDmd else Abs
+ | id <- arg_ids ])
+
+ tycon = classTyCon clas
+ new_tycon = isNewTyCon tycon
+ [data_con] = tyConDataCons tycon
+ tyvars = dataConUnivTyVars data_con
+ arg_tys = dataConRepArgTys data_con -- Includes the dictionary superclasses
+ eq_theta = dataConEqTheta data_con
+ n_eq_args = length eq_theta
+
+ -- 'index' is a 0-index into the *value* arguments of the dictionary
+ val_index = assoc "MkId.mkDictSelId" sel_index_prs name
+ sel_index_prs = map idName (classAllSelIds clas) `zip` [0..]
+
+ the_arg_id = arg_ids !! val_index
+ pred = mkClassPred clas (mkTyVarTys tyvars)
+ dict_id = mkTemplateLocal 1 $ mkPredTy pred
+ arg_ids = mkTemplateLocalsNum 2 arg_tys
+ eq_ids = map mkWildEvBinder eq_theta
rhs = mkLams tyvars (Lam dict_id rhs_body)
- rhs_body | isNewTyCon tycon = unwrapNewTypeBody tycon (map mkTyVarTy tyvars) (Var dict_id)
- | otherwise = Case (Var dict_id) dict_id (idType the_arg_id)
- [(DataAlt data_con, eq_ids ++ arg_ids, Var the_arg_id)]
-
-dictSelRule :: Int -> Arity -> [CoreExpr] -> Maybe CoreExpr
--- Oh, very clever
--- op_i t1..tk (df s1..sn d1..dm) = op_i_helper s1..sn d1..dm
--- op_i t1..tk (D t1..tk op1 ... opm) = opi
+ rhs_body | new_tycon = unwrapNewTypeBody tycon (map mkTyVarTy tyvars) (Var dict_id)
+ | otherwise = Case (Var dict_id) dict_id (idType the_arg_id)
+ [(DataAlt data_con, eq_ids ++ arg_ids, Var the_arg_id)]
+
+dictSelRule :: Int -> Arity -> Arity
+ -> IdUnfoldingFun -> [CoreExpr] -> Maybe CoreExpr
+-- Tries to persuade the argument to look like a constructor
+-- application, using exprIsConApp_maybe, and then selects
+-- from it
+-- sel_i t1..tk (D t1..tk op1 ... opm) = opi
--
--- NB: the data constructor has the same number of type args as the class op
-
-dictSelRule index n_ty_args args
+dictSelRule val_index n_ty_args n_eq_args id_unf args
| (dict_arg : _) <- drop n_ty_args args
- , Just (_, _, val_args) <- exprIsConApp_maybe dict_arg
- = Just (val_args !! index)
+ , Just (_, _, con_args) <- exprIsConApp_maybe id_unf dict_arg
+ , let val_args = drop n_eq_args con_args
+ = Just (val_args !! val_index)
| otherwise
= Nothing
\end{code}
-- Type variable case
go (arg:args) stricts us
- | isTyVar arg
+ | isTyCoVar arg
= let (binds, args') = go args stricts us
in (binds, arg:args')
info = noCafIdInfo
`setSpecInfo` mkSpecInfo (primOpRules prim_op name)
`setArityInfo` arity
- `setAllStrictnessInfo` Just strict_sig
+ `setStrictnessInfo` 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,
info = noCafIdInfo
`setArityInfo` arity
- `setAllStrictnessInfo` Just strict_sig
+ `setStrictnessInfo` Just strict_sig
(_, tau) = tcSplitForAllTys ty
(arg_tys, _) = tcSplitFunTys tau
mkBreakPointOpId uniq mod ix = mkTickBox' uniq mod ix ty
where ty = mkSigmaTy [openAlphaTyVar] [] openAlphaTy
+mkTickBox' :: Unique -> Module -> TickBoxId -> Type -> Id
mkTickBox' uniq mod ix ty = mkGlobalId (TickBoxOpId tickbox) name ty info
where
tickbox = TickBox mod ix
that they aren't discarded by the occurrence analyser.
\begin{code}
-mkDefaultMethodId dm_name ty = mkExportedLocalId dm_name ty
+mkDefaultMethodId :: Id -- Selector Id
+ -> Name -- Default method name
+ -> Id -- Default method Id
+mkDefaultMethodId sel_id dm_name = mkExportedLocalId dm_name (idType sel_id)
mkDictFunId :: Name -- Name to use for the dict fun;
-> [TyVar]
-> Class
-> [Type]
-> Id
+-- Implements the DFun Superclass Invariant (see TcInstDcls)
-mkDictFunId dfun_name inst_tyvars dfun_theta clas inst_tys
- = mkExportedLocalVar (DFunId is_nt) dfun_name dfun_ty vanillaIdInfo
+mkDictFunId dfun_name tvs theta clas tys
+ = mkExportedLocalVar (DFunId n_silent is_nt)
+ dfun_name
+ dfun_ty
+ vanillaIdInfo
where
is_nt = isNewTyCon (classTyCon clas)
- dfun_ty = mkSigmaTy inst_tyvars dfun_theta (mkDictTy clas inst_tys)
+ (n_silent, dfun_ty) = mkDictFunTy tvs theta clas tys
+
+mkDictFunTy :: [TyVar] -> ThetaType -> Class -> [Type] -> (Int, Type)
+mkDictFunTy tvs theta clas tys
+ = (length silent_theta, dfun_ty)
+ where
+ dfun_ty = mkSigmaTy tvs (silent_theta ++ theta) (mkDictTy clas tys)
+ silent_theta = filterOut discard $
+ substTheta (zipTopTvSubst (classTyVars clas) tys)
+ (classSCTheta clas)
+ -- See Note [Silent Superclass Arguments]
+ discard pred = isEmptyVarSet (tyVarsOfPred pred)
+ || any (`tcEqPred` pred) theta
+ -- See the DFun Superclass Invariant in TcInstDcls
\end{code}
another gun with which to shoot yourself in the foot.
\begin{code}
-mkWiredInIdName mod fs uniq id
- = mkWiredInName mod (mkOccNameFS varName fs) uniq (AnId id) UserSyntax
-
+lazyIdName, unsafeCoerceName, nullAddrName, seqName, realWorldName :: Name
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 gHC_BASE (fsLit "lazy") lazyIdKey lazyId
-
-errorName = mkWiredInIdName gHC_ERR (fsLit "error") errorIdKey eRROR_ID
-recSelErrorName = mkWiredInIdName cONTROL_EXCEPTION_BASE (fsLit "recSelError") recSelErrorIdKey rEC_SEL_ERROR_ID
-runtimeErrorName = mkWiredInIdName cONTROL_EXCEPTION_BASE (fsLit "runtimeError") runtimeErrorIdKey rUNTIME_ERROR_ID
-irrefutPatErrorName = mkWiredInIdName cONTROL_EXCEPTION_BASE (fsLit "irrefutPatError") irrefutPatErrorIdKey iRREFUT_PAT_ERROR_ID
-recConErrorName = mkWiredInIdName cONTROL_EXCEPTION_BASE (fsLit "recConError") recConErrorIdKey rEC_CON_ERROR_ID
-patErrorName = mkWiredInIdName cONTROL_EXCEPTION_BASE (fsLit "patError") patErrorIdKey pAT_ERROR_ID
-noMethodBindingErrorName = mkWiredInIdName cONTROL_EXCEPTION_BASE (fsLit "noMethodBindingError")
- noMethodBindingErrorIdKey nO_METHOD_BINDING_ERROR_ID
-nonExhaustiveGuardsErrorName
- = mkWiredInIdName cONTROL_EXCEPTION_BASE (fsLit "nonExhaustiveGuardsError")
- nonExhaustiveGuardsErrorIdKey nON_EXHAUSTIVE_GUARDS_ERROR_ID
\end{code}
\begin{code}
------------------------------------------------
-- unsafeCoerce# :: forall a b. a -> b
+unsafeCoerceId :: Id
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] $
- Cast (Var x) (mkUnsafeCoercion openAlphaTy openBetaTy)
+ ty = mkForAllTys [argAlphaTyVar,openBetaTyVar]
+ (mkFunTy argAlphaTy openBetaTy)
+ [x] = mkTemplateLocals [argAlphaTy]
+ rhs = mkLams [argAlphaTyVar,openBetaTyVar,x] $
+ Cast (Var x) (mkUnsafeCoercion argAlphaTy openBetaTy)
------------------------------------------------
nullAddrId :: Id
`setSpecInfo` mkSpecInfo [seq_cast_rule]
- ty = mkForAllTys [alphaTyVar,openBetaTyVar]
- (mkFunTy alphaTy (mkFunTy openBetaTy openBetaTy))
- [x,y] = mkTemplateLocals [alphaTy, openBetaTy]
- rhs = mkLams [alphaTyVar,openBetaTyVar,x,y] (Case (Var x) x openBetaTy [(DEFAULT, [], Var y)])
+ ty = mkForAllTys [alphaTyVar,argBetaTyVar]
+ (mkFunTy alphaTy (mkFunTy argBetaTy argBetaTy))
+ [x,y] = mkTemplateLocals [alphaTy, argBetaTy]
+ rhs = mkLams [alphaTyVar,argBetaTyVar,x,y] (Case (Var x) x argBetaTy [(DEFAULT, [], Var y)])
-- See Note [Built-in RULES for seq]
seq_cast_rule = BuiltinRule { ru_name = fsLit "seq of cast"
, ru_try = match_seq_of_cast
}
-match_seq_of_cast :: [CoreExpr] -> Maybe CoreExpr
+match_seq_of_cast :: IdUnfoldingFun -> [CoreExpr] -> Maybe CoreExpr
-- See Note [Built-in RULES for seq]
-match_seq_of_cast [Type _, Type res_ty, Cast scrut co, expr]
+match_seq_of_cast _ [Type _, Type res_ty, Cast scrut co, expr]
= Just (Var seqId `mkApps` [Type (fst (coercionKind co)), Type res_ty,
scrut, expr])
-match_seq_of_cast _ = Nothing
+match_seq_of_cast _ _ = Nothing
------------------------------------------------
lazyId :: Id -- See Note [lazyId magic]
Note [seqId magic]
~~~~~~~~~~~~~~~~~~
-'GHC.Prim.seq' is special in several ways.
+'GHC.Prim.seq' is special in several ways.
a) Its second arg can have an unboxed type
x `seq` (v +# w)
d) There is some special rule handing: Note [User-defined RULES for seq]
+e) See Note [Typing rule for seq] in TcExpr.
+
Note [User-defined RULES for seq]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Roman found situations where he had
This comes up in strictness analysis
\begin{code}
+realWorldPrimId :: Id
realWorldPrimId -- :: State# RealWorld
= pcMiscPrelId realWorldName realWorldStatePrimTy
(noCafIdInfo `setUnfoldingInfo` evaldUnfolding)
\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 (mkMachString err_msg)
-
-mkImpossibleExpr :: Type -> CoreExpr
-mkImpossibleExpr res_ty
- = mkRuntimeErrorApp rUNTIME_ERROR_ID res_ty "Impossible case alternative"
-
-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 -> Id
-mkRuntimeErrorId name = pc_bottoming_Id name runtimeErrorTy
-
-runtimeErrorTy :: Type
-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
-- 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 -> Type -> Id
--- Function of arity 1, which diverges after being given one argument
-pc_bottoming_Id name ty
- = pcMiscPrelId name ty bottoming_info
- where
- bottoming_info = vanillaIdInfo `setAllStrictnessInfo` Just strict_sig
- `setArityInfo` 1
- -- Make arity and strictness agree
-
- -- 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
\end{code}
-