X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FdeSugar%2FDsCCall.lhs;h=57bace20008452697a943c95baab6d7a2932c580;hb=423d477bfecd490de1449c59325c8776f91d7aac;hp=35722fae20d7407dfe710a2f2575addfdd970e9e;hpb=783e505e2d884f94d30ec8074e590507f2561c49;p=ghc-hetmet.git diff --git a/ghc/compiler/deSugar/DsCCall.lhs b/ghc/compiler/deSugar/DsCCall.lhs index 35722fa..57bace2 100644 --- a/ghc/compiler/deSugar/DsCCall.lhs +++ b/ghc/compiler/deSugar/DsCCall.lhs @@ -1,47 +1,73 @@ % % (c) The AQUA Project, Glasgow University, 1994-1998 % -\section[DsCCall]{Desugaring \tr{_ccall_}s and \tr{_casm_}s} +\section[DsCCall]{Desugaring C calls} \begin{code} module DsCCall ( dsCCall - , mkCCall + , mkFCall , unboxArg , boxResult - , wrapUnboxedValue - , can'tSeeDataConsPanic - + , resultWrapper ) where #include "HsVersions.h" + import CoreSyn import DsMonad -import DsUtils -import TcHsSyn ( maybeBoxedPrimType ) -import CoreUtils ( exprType ) +import CoreUtils ( exprType, mkCoerce2 ) import Id ( Id, mkWildId ) -import MkId ( mkCCallOpId ) +import MkId ( mkFCallId, realWorldPrimId, mkPrimOpId ) import Maybes ( maybeToBool ) -import PrelInfo ( packStringForCId ) -import PrimOp ( PrimOp(..), CCall(..), CCallTarget(..) ) -import DataCon ( DataCon, splitProductType_maybe ) -import CallConv -import Type ( isUnLiftedType, splitAlgTyConApp_maybe, mkFunTys, - splitTyConApp_maybe, tyVarsOfType, mkForAllTys, Type +import ForeignCall ( ForeignCall(..), CCallSpec(..), CCallTarget(..), Safety, + CCallConv(..), CLabelString ) +import DataCon ( splitProductType_maybe, dataConSourceArity, dataConWrapId ) +import ForeignCall ( ForeignCall, CCallTarget(..) ) + +import TcType ( tcSplitTyConApp_maybe ) +import Type ( Type, isUnLiftedType, mkFunTys, mkFunTy, + tyVarsOfType, mkForAllTys, mkTyConApp, + isPrimitiveType, splitTyConApp_maybe, + splitRecNewType_maybe, splitForAllTy_maybe, + isUnboxedTupleType + ) + +import PrimOp ( PrimOp(..) ) +import TysPrim ( realWorldStatePrimTy, intPrimTy, + byteArrayPrimTyCon, mutableByteArrayPrimTyCon, + addrPrimTy ) -import TysPrim ( byteArrayPrimTy, realWorldStatePrimTy, - byteArrayPrimTyCon, mutableByteArrayPrimTyCon ) -import TysWiredIn ( unitDataConId, stringTy, - unboxedPairDataCon, - mkUnboxedTupleTy, unboxedTupleCon +import TyCon ( TyCon, tyConDataCons, tyConName ) +import TysWiredIn ( unitDataConId, + unboxedSingletonDataCon, unboxedPairDataCon, + unboxedSingletonTyCon, unboxedPairTyCon, + trueDataCon, falseDataCon, + trueDataConId, falseDataConId, + listTyCon, charTyCon, + tupleTyCon, tupleCon + ) +import BasicTypes ( Boxity(..) ) +import Literal ( mkMachInt ) +import PrelNames ( Unique, hasKey, ioTyConKey, boolTyConKey, unitTyConKey, + int8TyConKey, int16TyConKey, int32TyConKey, + word8TyConKey, word16TyConKey, word32TyConKey + -- dotnet interop + , marshalStringName, unmarshalStringName + , marshalObjectName, unmarshalObjectName + , objectTyConName ) -import Unique ( Unique ) import VarSet ( varSetElems ) +import Constants ( wORD_SIZE) import Outputable + +#ifdef DEBUG +import TypeRep +#endif + \end{code} Desugaring of @ccall@s consists of adding some state manipulation, @@ -80,28 +106,24 @@ follows: \end{verbatim} \begin{code} -dsCCall :: FAST_STRING -- C routine to invoke +dsCCall :: CLabelString -- C routine to invoke -> [CoreExpr] -- Arguments (desugared) - -> Bool -- True <=> might cause Haskell GC - -> Bool -- True <=> really a "_casm_" - -> Type -- Type of the result (a boxed-prim IO type) + -> Safety -- Safety of the call + -> Type -- Type of the result: IO t -> DsM CoreExpr -dsCCall lbl args may_gc is_asm result_ty - = newSysLocalDs realWorldStatePrimTy `thenDs` \ old_s -> - - mapAndUnzipDs unboxArg args `thenDs` \ (unboxed_args, arg_wrappers) -> - boxResult result_ty `thenDs` \ (final_result_ty, res_wrapper) -> - getUniqueDs `thenDs` \ uniq -> +dsCCall lbl args may_gc result_ty + = mapAndUnzipDs unboxArg args `thenDs` \ (unboxed_args, arg_wrappers) -> + boxResult [] id Nothing result_ty `thenDs` \ (ccall_result_ty, res_wrapper) -> + newUnique `thenDs` \ uniq -> let - val_args = Var old_s : unboxed_args - the_ccall = CCall (StaticTarget lbl) is_asm may_gc cCallConv - the_prim_app = mkCCall uniq the_ccall val_args final_result_ty - the_body = foldr ($) (res_wrapper the_prim_app) arg_wrappers + target = StaticTarget lbl + the_fcall = CCall (CCallSpec target CCallConv may_gc) + the_prim_app = mkFCall uniq the_fcall unboxed_args ccall_result_ty in - returnDs (Lam old_s the_body) + returnDs (foldr ($) (res_wrapper the_prim_app) arg_wrappers) -mkCCall :: Unique -> CCall +mkFCall :: Unique -> ForeignCall -> [CoreExpr] -- Args -> Type -- Result type -> CoreExpr @@ -114,14 +136,14 @@ mkCCall :: Unique -> CCall -- Here we build a ccall thus -- (ccallid::(forall a b. StablePtr (a -> b) -> Addr -> Char -> IO Addr)) -- a b s x c -mkCCall uniq the_ccall val_args res_ty - = mkApps (mkVarApps (Var the_ccall_id) tyvars) val_args +mkFCall uniq the_fcall val_args res_ty + = mkApps (mkVarApps (Var the_fcall_id) tyvars) val_args where arg_tys = map exprType val_args body_ty = (mkFunTys arg_tys res_ty) tyvars = varSetElems (tyVarsOfType body_ty) ty = mkForAllTys tyvars body_ty - the_ccall_id = mkCCallOpId uniq the_ccall ty + the_fcall_id = mkFCallId uniq the_fcall ty \end{code} \begin{code} @@ -129,32 +151,47 @@ unboxArg :: CoreExpr -- The supplied argument -> DsM (CoreExpr, -- To pass as the actual argument CoreExpr -> CoreExpr -- Wrapper to unbox the arg ) -unboxArg arg +-- Example: if the arg is e::Int, unboxArg will return +-- (x#::Int#, \W. case x of I# x# -> W) +-- where W is a CoreExpr that probably mentions x# - -- Primitive types - -- ADR Question: can this ever be used? None of the PrimTypes are - -- instances of the CCallable class. - -- - -- SOF response: - -- Oh yes they are, I've just added them :-) Having _ccall_ and _casm_ - -- that accept unboxed arguments is a Good Thing if you have a stub generator - -- which generates the boiler-plate box-unbox code for you, i.e., it may help - -- us nuke this very module :-) - -- - | isUnLiftedType arg_ty +unboxArg arg + -- Primtive types: nothing to unbox + | isPrimitiveType arg_ty = returnDs (arg, \body -> body) - -- Strings - | arg_ty == stringTy - -- ToDo (ADR): - allow synonyms of Strings too? - = newSysLocalDs byteArrayPrimTy `thenDs` \ prim_arg -> + -- Recursive newtypes + | Just rep_ty <- splitRecNewType_maybe arg_ty + = unboxArg (mkCoerce2 rep_ty arg_ty arg) + + -- Booleans + | Just (tc,_) <- splitTyConApp_maybe arg_ty, + tc `hasKey` boolTyConKey + = newSysLocalDs intPrimTy `thenDs` \ prim_arg -> returnDs (Var prim_arg, - \body -> Case (App (Var packStringForCId) arg) - prim_arg [(DEFAULT,[],body)]) + \ body -> Case (Case arg (mkWildId arg_ty) + [(DataAlt falseDataCon,[],mkIntLit 0), + (DataAlt trueDataCon, [],mkIntLit 1)]) + prim_arg + [(DEFAULT,[],body)]) + + -- Data types with a single constructor, which has a single, primitive-typed arg + -- This deals with Int, Float etc; also Ptr, ForeignPtr + | is_product_type && data_con_arity == 1 + = ASSERT2(isUnLiftedType data_con_arg_ty1, pprType arg_ty) + -- Typechecker ensures this + newSysLocalDs arg_ty `thenDs` \ case_bndr -> + newSysLocalDs data_con_arg_ty1 `thenDs` \ prim_arg -> + returnDs (Var prim_arg, + \ body -> Case arg case_bndr [(DataAlt data_con,[prim_arg],body)] + ) -- Byte-arrays, both mutable and otherwise; hack warning + -- We're looking for values of type ByteArray, MutableByteArray + -- data ByteArray ix = ByteArray ix ix ByteArray# + -- data MutableByteArray s ix = MutableByteArray ix ix (MutableByteArray# s) | is_product_type && - length data_con_arg_tys == 3 && + data_con_arity == 3 && maybeToBool maybe_arg3_tycon && (arg3_tycon == byteArrayPrimTyCon || arg3_tycon == mutableByteArrayPrimTyCon) @@ -165,124 +202,252 @@ unboxArg arg \ body -> Case arg case_bndr [(DataAlt data_con,vars,body)] ) - -- Data types with a single constructor, which has a single, primitive-typed arg - | maybeToBool maybe_boxed_prim_arg_ty - = newSysLocalDs arg_ty `thenDs` \ case_bndr -> - newSysLocalDs the_prim_arg_ty `thenDs` \ prim_arg -> - returnDs (Var prim_arg, - \ body -> Case arg case_bndr [(DataAlt box_data_con,[prim_arg],body)] - ) + | Just (tc, [arg_ty]) <- splitTyConApp_maybe arg_ty, + tc == listTyCon, + Just (cc,[]) <- splitTyConApp_maybe arg_ty, + cc == charTyCon + -- String; dotnet only + = dsLookupGlobalId marshalStringName `thenDs` \ unpack_id -> + newSysLocalDs addrPrimTy `thenDs` \ prim_string -> + returnDs (Var prim_string, + \ body -> + let + io_ty = exprType body + (Just (_,[io_arg])) = tcSplitTyConApp_maybe io_ty + in + mkApps (Var unpack_id) + [ Type io_arg + , arg + , Lam prim_string body + ]) + | Just (tc, [arg_ty]) <- splitTyConApp_maybe arg_ty, + tyConName tc == objectTyConName + -- Object; dotnet only + = dsLookupGlobalId marshalObjectName `thenDs` \ unpack_id -> + newSysLocalDs addrPrimTy `thenDs` \ prim_obj -> + returnDs (Var prim_obj, + \ body -> + let + io_ty = exprType body + (Just (_,[io_arg])) = tcSplitTyConApp_maybe io_ty + in + mkApps (Var unpack_id) + [ Type io_arg + , arg + , Lam prim_obj body + ]) | otherwise - = getSrcLocDs `thenDs` \ l -> + = getSrcSpanDs `thenDs` \ l -> pprPanic "unboxArg: " (ppr l <+> ppr arg_ty) where - arg_ty = exprType arg - - maybe_boxed_prim_arg_ty = maybeBoxedPrimType arg_ty - (Just (box_data_con, the_prim_arg_ty)) = maybe_boxed_prim_arg_ty - - maybe_product_type = splitProductType_maybe arg_ty - is_product_type = maybeToBool maybe_product_type - Just (tycon, _, data_con, data_con_arg_tys) = maybe_product_type - (data_con_arg_ty1 : data_con_arg_ty2 : data_con_arg_ty3 :_) - = data_con_arg_tys - - maybe_arg3_tycon = splitTyConApp_maybe data_con_arg_ty3 - Just (arg3_tycon,_) = maybe_arg3_tycon - -can'tSeeDataConsPanic thing ty - = pprPanic - "ERROR: Can't see the data constructor(s) for _ccall_/_casm_/foreign declaration" - (hcat [ text thing, text "; type: ", ppr ty - , text "(try compiling with -fno-prune-tydecls ..)\n"]) + arg_ty = exprType arg + maybe_product_type = splitProductType_maybe arg_ty + is_product_type = maybeToBool maybe_product_type + Just (_, _, data_con, data_con_arg_tys) = maybe_product_type + data_con_arity = dataConSourceArity data_con + (data_con_arg_ty1 : _) = data_con_arg_tys + + (_ : _ : data_con_arg_ty3 : _) = data_con_arg_tys + maybe_arg3_tycon = splitTyConApp_maybe data_con_arg_ty3 + Just (arg3_tycon,_) = maybe_arg3_tycon \end{code} \begin{code} -boxResult :: Type -- Type of desired result - -> DsM (Type, -- Type of the result of the ccall itself - CoreExpr -> CoreExpr) -- Wrapper for the ccall - -- to box the result -boxResult result_ty - -- Data types with a single nullary constructor - | (maybeToBool maybe_product_type) && -- Data type - (null data_con_arg_tys) - = - newSysLocalDs realWorldStatePrimTy `thenDs` \ prim_state_id -> -{- - wrapUnboxedValue result_ty `thenDs` \ (state_and_prim_datacon, - state_and_prim_ty, prim_result_id, the_result) -> - mkConDs ioOkDataCon - [TyArg result_ty, VarArg (Var prim_state_id), VarArg the_result] - `thenDs` \ the_pair -> --} - let - the_pair = mkConApp unboxedPairDataCon - [Type realWorldStatePrimTy, Type result_ty, - Var prim_state_id, - Var unitDataConId] - the_alt = (DataAlt (unboxedTupleCon 1), [prim_state_id], the_pair) - scrut_ty = mkUnboxedTupleTy 1 [realWorldStatePrimTy] - in - returnDs (scrut_ty, \prim_app -> Case prim_app (mkWildId scrut_ty) [the_alt] - ) - - -- Data types with a single constructor, which has a single, primitive-typed arg - | (maybeToBool maybe_product_type) && -- Data type - not (null data_con_arg_tys) && null other_args_tys && -- Just one arg - isUnLiftedType the_prim_result_ty -- of primitive type - = - newSysLocalDs realWorldStatePrimTy `thenDs` \ prim_state_id -> - newSysLocalDs the_prim_result_ty `thenDs` \ prim_result_id -> - newSysLocalDs ccall_res_type `thenDs` \ case_bndr -> - - let - the_result = mkConApp data_con (map Type tycon_arg_tys ++ [Var prim_result_id]) - the_pair = mkConApp unboxedPairDataCon - [Type realWorldStatePrimTy, Type result_ty, - Var prim_state_id, the_result] - the_alt = (DataAlt unboxedPairDataCon, [prim_state_id, prim_result_id], the_pair) - in - returnDs (ccall_res_type, \prim_app -> Case prim_app case_bndr [the_alt] - ) - - | otherwise - = pprPanic "boxResult: " (ppr result_ty) +boxResult :: [Id] + -> ((Maybe Type, CoreExpr -> CoreExpr) -> (Maybe Type, CoreExpr -> CoreExpr)) + -> Maybe Id + -> Type + -> DsM (Type, CoreExpr -> CoreExpr) + +-- Takes the result of the user-level ccall: +-- either (IO t), +-- or maybe just t for an side-effect-free call +-- Returns a wrapper for the primitive ccall itself, along with the +-- type of the result of the primitive ccall. This result type +-- will be of the form +-- State# RealWorld -> (# State# RealWorld, t' #) +-- where t' is the unwrapped form of t. If t is simply (), then +-- the result type will be +-- State# RealWorld -> (# State# RealWorld #) + +boxResult arg_ids augment mbTopCon result_ty + = case tcSplitTyConApp_maybe result_ty of + -- This split absolutely has to be a tcSplit, because we must + -- see the IO type; and it's a newtype which is transparent to splitTyConApp. + + -- The result is IO t, so wrap the result in an IO constructor + Just (io_tycon, [io_res_ty]) | io_tycon `hasKey` ioTyConKey + -> resultWrapper io_res_ty `thenDs` \ res -> + let aug_res = augment res + extra_result_tys = + case aug_res of + (Just ty,_) + | isUnboxedTupleType ty -> + let (Just (_, ls)) = splitTyConApp_maybe ty in tail ls + _ -> [] + in + mk_alt (return_result extra_result_tys) aug_res + `thenDs` \ (ccall_res_ty, the_alt) -> + newSysLocalDs realWorldStatePrimTy `thenDs` \ state_id -> + let + io_data_con = head (tyConDataCons io_tycon) + toIOCon = + case mbTopCon of + Nothing -> dataConWrapId io_data_con + Just x -> x + wrap = \ the_call -> + mkApps (Var toIOCon) + [ Type io_res_ty, + Lam state_id $ + Case (App the_call (Var state_id)) + (mkWildId ccall_res_ty) + [the_alt] + ] + in + returnDs (realWorldStatePrimTy `mkFunTy` ccall_res_ty, wrap) + where + return_result ts state anss + = mkConApp (tupleCon Unboxed (2 + length ts)) + (Type realWorldStatePrimTy : Type io_res_ty : map Type ts ++ + state : anss) + -- It isn't, so do unsafePerformIO + -- It's not conveniently available, so we inline it + other -> resultWrapper result_ty `thenDs` \ res -> + mk_alt return_result (augment res) `thenDs` \ (ccall_res_ty, the_alt) -> + let + wrap = \ the_call -> Case (App the_call (Var realWorldPrimId)) + (mkWildId ccall_res_ty) + [the_alt] + in + returnDs (realWorldStatePrimTy `mkFunTy` ccall_res_ty, wrap) + where + return_result state [ans] = ans + return_result _ _ = panic "return_result: expected single result" where - maybe_product_type = splitProductType_maybe result_ty - Just (tycon, tycon_arg_tys, data_con, data_con_arg_tys) = maybe_product_type - (the_prim_result_ty : other_args_tys) = data_con_arg_tys - - ccall_res_type = mkUnboxedTupleTy 2 [realWorldStatePrimTy, the_prim_result_ty] - --- wrap up an unboxed value. -wrapUnboxedValue :: Type -> DsM (Type, Id, CoreExpr) -wrapUnboxedValue ty - | (maybeToBool maybe_product_type) && -- Data type - not (null data_con_arg_tys) && null other_args_tys && -- Just one arg - isUnLiftedType the_prim_result_ty -- of primitive type - = - newSysLocalDs the_prim_result_ty `thenDs` \ prim_result_id -> - let - the_result = mkConApp data_con (map Type tycon_arg_tys ++ [Var prim_result_id]) + mk_alt return_result (Nothing, wrap_result) + = -- The ccall returns () + newSysLocalDs realWorldStatePrimTy `thenDs` \ state_id -> + let + the_rhs = return_result (Var state_id) + [wrap_result (panic "boxResult")] + + ccall_res_ty = mkTyConApp unboxedSingletonTyCon [realWorldStatePrimTy] + the_alt = (DataAlt unboxedSingletonDataCon, [state_id], the_rhs) + in + returnDs (ccall_res_ty, the_alt) + + mk_alt return_result (Just prim_res_ty, wrap_result) + -- The ccall returns a non-() value + | isUnboxedTupleType prim_res_ty + = let + Just (_, ls) = splitTyConApp_maybe prim_res_ty + arity = 1 + length ls + in + mappM newSysLocalDs ls `thenDs` \ args_ids@(result_id:as) -> + newSysLocalDs realWorldStatePrimTy `thenDs` \ state_id -> + let + the_rhs = return_result (Var state_id) + (wrap_result (Var result_id) : map Var as) + ccall_res_ty = mkTyConApp (tupleTyCon Unboxed arity) + (realWorldStatePrimTy : ls) + the_alt = ( DataAlt (tupleCon Unboxed arity) + , (state_id : args_ids) + , the_rhs + ) + in + returnDs (ccall_res_ty, the_alt) + | otherwise + = newSysLocalDs prim_res_ty `thenDs` \ result_id -> + newSysLocalDs realWorldStatePrimTy `thenDs` \ state_id -> + let + the_rhs = return_result (Var state_id) + [wrap_result (Var result_id)] + + ccall_res_ty = mkTyConApp unboxedPairTyCon [realWorldStatePrimTy, prim_res_ty] + the_alt = (DataAlt unboxedPairDataCon, [state_id, result_id], the_rhs) + in + returnDs (ccall_res_ty, the_alt) + + +resultWrapper :: Type + -> DsM (Maybe Type, -- Type of the expected result, if any + CoreExpr -> CoreExpr) -- Wrapper for the result +resultWrapper result_ty + -- Base case 1: primitive types + | isPrimitiveType result_ty + = returnDs (Just result_ty, \e -> e) + + -- Base case 2: the unit type () + | Just (tc,_) <- maybe_tc_app, tc `hasKey` unitTyConKey + = returnDs (Nothing, \e -> Var unitDataConId) + + -- Base case 3: the boolean type + | Just (tc,_) <- maybe_tc_app, tc `hasKey` boolTyConKey + = returnDs + (Just intPrimTy, \e -> Case e (mkWildId intPrimTy) + [(DEFAULT ,[],Var trueDataConId ), + (LitAlt (mkMachInt 0),[],Var falseDataConId)]) + + -- Recursive newtypes + | Just rep_ty <- splitRecNewType_maybe result_ty + = resultWrapper rep_ty `thenDs` \ (maybe_ty, wrapper) -> + returnDs (maybe_ty, \e -> mkCoerce2 result_ty rep_ty (wrapper e)) + + -- The type might contain foralls (eg. for dummy type arguments, + -- referring to 'Ptr a' is legal). + | Just (tyvar, rest) <- splitForAllTy_maybe result_ty + = resultWrapper rest `thenDs` \ (maybe_ty, wrapper) -> + returnDs (maybe_ty, \e -> Lam tyvar (wrapper e)) + + -- Data types with a single constructor, which has a single arg + -- This includes types like Ptr and ForeignPtr + | Just (tycon, tycon_arg_tys, data_con, data_con_arg_tys) <- splitProductType_maybe result_ty, + dataConSourceArity data_con == 1 + = let + (unwrapped_res_ty : _) = data_con_arg_tys + narrow_wrapper = maybeNarrow tycon in - returnDs (ccall_res_type, prim_result_id, the_result) - - -- Data types with a single nullary constructor - | (maybeToBool maybe_product_type) && -- Data type - (null data_con_arg_tys) - = - let - scrut_ty = mkUnboxedTupleTy 1 [realWorldStatePrimTy] - in - returnDs (scrut_ty, unitDataConId, Var unitDataConId) + resultWrapper unwrapped_res_ty `thenDs` \ (maybe_ty, wrapper) -> + returnDs + (maybe_ty, \e -> mkApps (Var (dataConWrapId data_con)) + (map Type tycon_arg_tys ++ [wrapper (narrow_wrapper e)])) + + -- Strings; 'dotnet' only. + | Just (tc, [arg_ty]) <- maybe_tc_app, tc == listTyCon, + Just (cc,[]) <- splitTyConApp_maybe arg_ty, cc == charTyCon + = dsLookupGlobalId unmarshalStringName `thenDs` \ pack_id -> + returnDs (Just addrPrimTy, + \ e -> App (Var pack_id) e) + + -- Objects; 'dotnet' only. + | Just (tc, [arg_ty]) <- maybe_tc_app, + tyConName tc == objectTyConName + = dsLookupGlobalId unmarshalObjectName `thenDs` \ pack_id -> + returnDs (Just addrPrimTy, + \ e -> App (Var pack_id) e) | otherwise - = pprPanic "boxResult: " (ppr ty) - where - maybe_product_type = splitProductType_maybe ty - Just (tycon, tycon_arg_tys, data_con, data_con_arg_tys) = maybe_product_type - (the_prim_result_ty : other_args_tys) = data_con_arg_tys - ccall_res_type = mkUnboxedTupleTy 2 [realWorldStatePrimTy, the_prim_result_ty] + = pprPanic "resultWrapper" (ppr result_ty) + where + maybe_tc_app = splitTyConApp_maybe result_ty + +-- When the result of a foreign call is smaller than the word size, we +-- need to sign- or zero-extend the result up to the word size. The C +-- standard appears to say that this is the responsibility of the +-- caller, not the callee. + +maybeNarrow :: TyCon -> (CoreExpr -> CoreExpr) +maybeNarrow tycon + | tycon `hasKey` int8TyConKey = \e -> App (Var (mkPrimOpId Narrow8IntOp)) e + | tycon `hasKey` int16TyConKey = \e -> App (Var (mkPrimOpId Narrow16IntOp)) e + | tycon `hasKey` int32TyConKey + && wORD_SIZE > 4 = \e -> App (Var (mkPrimOpId Narrow32IntOp)) e + + | tycon `hasKey` word8TyConKey = \e -> App (Var (mkPrimOpId Narrow8WordOp)) e + | tycon `hasKey` word16TyConKey = \e -> App (Var (mkPrimOpId Narrow16WordOp)) e + | tycon `hasKey` word32TyConKey + && wORD_SIZE > 4 = \e -> App (Var (mkPrimOpId Narrow32WordOp)) e + | otherwise = id \end{code}