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Diffstat (limited to 'compiler/deSugar/DsCCall.lhs')
| -rw-r--r-- | compiler/deSugar/DsCCall.lhs | 456 |
1 files changed, 456 insertions, 0 deletions
diff --git a/compiler/deSugar/DsCCall.lhs b/compiler/deSugar/DsCCall.lhs new file mode 100644 index 0000000000..3554197fb8 --- /dev/null +++ b/compiler/deSugar/DsCCall.lhs @@ -0,0 +1,456 @@ +% +% (c) The AQUA Project, Glasgow University, 1994-1998 +% +\section[DsCCall]{Desugaring C calls} + +\begin{code} +module DsCCall + ( dsCCall + , mkFCall + , unboxArg + , boxResult + , resultWrapper + ) where + +#include "HsVersions.h" + + +import CoreSyn + +import DsMonad + +import CoreUtils ( exprType, coreAltType, mkCoerce2 ) +import Id ( Id, mkWildId ) +import MkId ( mkFCallId, realWorldPrimId, mkPrimOpId ) +import Maybes ( maybeToBool ) +import ForeignCall ( ForeignCall(..), CCallSpec(..), CCallTarget(..), Safety, + CCallConv(..), CLabelString ) +import DataCon ( splitProductType_maybe, dataConSourceArity, dataConWrapId ) + +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 TyCon ( TyCon, tyConDataCons, tyConName ) +import TysWiredIn ( unitDataConId, + unboxedSingletonDataCon, unboxedPairDataCon, + unboxedSingletonTyCon, unboxedPairTyCon, + trueDataCon, falseDataCon, + trueDataConId, falseDataConId, + listTyCon, charTyCon, boolTy, + 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 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, +unboxing any boxed primitive arguments and boxing the result if +desired. + +The state stuff just consists of adding in +@PrimIO (\ s -> case s of { S# s# -> ... })@ in an appropriate place. + +The unboxing is straightforward, as all information needed to unbox is +available from the type. For each boxed-primitive argument, we +transform: +\begin{verbatim} + _ccall_ foo [ r, t1, ... tm ] e1 ... em + | + | + V + case e1 of { T1# x1# -> + ... + case em of { Tm# xm# -> xm# + ccall# foo [ r, t1#, ... tm# ] x1# ... xm# + } ... } +\end{verbatim} + +The reboxing of a @_ccall_@ result is a bit tricker: the types don't +contain information about the state-pairing functions so we have to +keep a list of \tr{(type, s-p-function)} pairs. We transform as +follows: +\begin{verbatim} + ccall# foo [ r, t1#, ... tm# ] e1# ... em# + | + | + V + \ s# -> case (ccall# foo [ r, t1#, ... tm# ] s# e1# ... em#) of + (StateAnd<r># result# state#) -> (R# result#, realWorld#) +\end{verbatim} + +\begin{code} +dsCCall :: CLabelString -- C routine to invoke + -> [CoreExpr] -- Arguments (desugared) + -> Safety -- Safety of the call + -> Type -- Type of the result: IO t + -> DsM CoreExpr + +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 + 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 (foldr ($) (res_wrapper the_prim_app) arg_wrappers) + +mkFCall :: Unique -> ForeignCall + -> [CoreExpr] -- Args + -> Type -- Result type + -> CoreExpr +-- Construct the ccall. The only tricky bit is that the ccall Id should have +-- no free vars, so if any of the arg tys do we must give it a polymorphic type. +-- [I forget *why* it should have no free vars!] +-- For example: +-- mkCCall ... [s::StablePtr (a->b), x::Addr, c::Char] +-- +-- Here we build a ccall thus +-- (ccallid::(forall a b. StablePtr (a -> b) -> Addr -> Char -> IO Addr)) +-- a b s x c +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_fcall_id = mkFCallId uniq the_fcall ty +\end{code} + +\begin{code} +unboxArg :: CoreExpr -- The supplied argument + -> DsM (CoreExpr, -- To pass as the actual argument + CoreExpr -> CoreExpr -- Wrapper to unbox the 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# + +unboxArg arg + -- Primtive types: nothing to unbox + | isPrimitiveType arg_ty + = returnDs (arg, \body -> body) + + -- 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 (Case arg (mkWildId arg_ty) intPrimTy + [(DataAlt falseDataCon,[],mkIntLit 0), + (DataAlt trueDataCon, [],mkIntLit 1)]) + -- In increasing tag order! + prim_arg + (exprType body) + [(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 (exprType body) [(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 && + data_con_arity == 3 && + maybeToBool maybe_arg3_tycon && + (arg3_tycon == byteArrayPrimTyCon || + arg3_tycon == mutableByteArrayPrimTyCon) + = newSysLocalDs arg_ty `thenDs` \ case_bndr -> + newSysLocalsDs data_con_arg_tys `thenDs` \ vars@[l_var, r_var, arr_cts_var] -> + returnDs (Var arr_cts_var, + \ body -> Case arg case_bndr (exprType body) [(DataAlt data_con,vars,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 + = getSrcSpanDs `thenDs` \ l -> + pprPanic "unboxArg: " (ppr l <+> ppr arg_ty) + where + 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 :: ((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 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) + (coreAltType the_alt) + [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) + (coreAltType the_alt) + [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 + 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) + boolTy + [(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 + 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 "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} |