%
-% (c) The AQUA Project, Glasgow University, 1994-1996
+% (c) The AQUA Project, Glasgow University, 1994-1998
%
\section[DsCCall]{Desugaring \tr{_ccall_}s and \tr{_casm_}s}
\begin{code}
-module DsCCall ( dsCCall ) where
+module DsCCall
+ ( dsCCall
+ , mkCCall
+ , unboxArg
+ , boxResult
+ , wrapUnboxedValue
+ , can'tSeeDataConsPanic
+
+ ) where
#include "HsVersions.h"
import DsUtils
import TcHsSyn ( maybeBoxedPrimType )
-import CoreUtils ( coreExprType )
-import Id ( Id(..), dataConArgTys, idType )
+import CoreUtils ( exprType )
+import Id ( Id, mkWildId )
+import MkId ( mkCCallOpId )
import Maybes ( maybeToBool )
-import PrelVals ( packStringForCId )
-import PrimOp ( PrimOp(..) )
-import Type ( isUnpointedType, splitAlgTyConApp_maybe,
- splitTyConApp_maybe, splitFunTys, splitForAllTys,
- Type
+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 TyCon ( tyConDataCons )
import TysPrim ( byteArrayPrimTy, realWorldStatePrimTy,
byteArrayPrimTyCon, mutableByteArrayPrimTyCon )
-import TysWiredIn ( getStatePairingConInfo,
- unitDataCon, stringTy,
- realWorldStateTy, stateDataCon
+import TysWiredIn ( unitDataConId, stringTy,
+ unboxedPairDataCon,
+ mkUnboxedTupleTy, unboxedTupleCon
)
+import Unique ( Unique )
+import VarSet ( varSetElems )
import Outputable
\end{code}
-> Type -- Type of the result (a boxed-prim IO type)
-> DsM CoreExpr
-dsCCall label args may_gc is_asm io_result_ty
+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 ->
let
- final_args = Var old_s : unboxed_args
- (ioOkDataCon, result_ty) = getIoOkDataCon io_result_ty
+ 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 ($) (res_wrapper the_prim_app) arg_wrappers
in
-
- boxResult ioOkDataCon result_ty `thenDs` \ (final_result_ty, res_wrapper) ->
-
- let
- the_ccall_op = CCallOp label is_asm may_gc
- (map coreExprType final_args)
- final_result_ty
- in
- mkPrimDs the_ccall_op (map VarArg final_args) `thenDs` \ the_prim_app ->
- let
- the_body = foldr ($) (res_wrapper the_prim_app) arg_wrappers
- in
- returnDs (Lam (ValBinder old_s) the_body)
+ returnDs (Lam old_s the_body)
+
+mkCCall :: Unique -> CCall
+ -> [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
+mkCCall uniq the_ccall val_args res_ty
+ = mkApps (mkVarApps (Var the_ccall_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
\end{code}
\begin{code}
-- which generates the boiler-plate box-unbox code for you, i.e., it may help
-- us nuke this very module :-)
--
- | isUnpointedType arg_ty
+ | isUnLiftedType arg_ty
= returnDs (arg, \body -> body)
-- Strings
| arg_ty == stringTy
-- ToDo (ADR): - allow synonyms of Strings too?
= newSysLocalDs byteArrayPrimTy `thenDs` \ prim_arg ->
- mkAppDs (Var packStringForCId) [VarArg arg] `thenDs` \ pack_appn ->
returnDs (Var prim_arg,
- \body -> Case pack_appn (PrimAlts []
- (BindDefault prim_arg body))
- )
-
- | null data_cons
- -- oops: we can't see the data constructors!!!
- = can't_see_datacons_error "argument" arg_ty
+ \body -> Case (App (Var packStringForCId) arg)
+ prim_arg [(DEFAULT,[],body)])
-- Byte-arrays, both mutable and otherwise; hack warning
- | is_data_type &&
- length data_con_arg_tys == 2 &&
- maybeToBool maybe_arg2_tycon &&
- (arg2_tycon == byteArrayPrimTyCon ||
- arg2_tycon == mutableByteArrayPrimTyCon)
+ | is_product_type &&
+ length data_con_arg_tys == 3 &&
+ maybeToBool maybe_arg3_tycon &&
+ (arg3_tycon == byteArrayPrimTyCon ||
+ arg3_tycon == mutableByteArrayPrimTyCon)
-- and, of course, it is an instance of CCallable
- = newSysLocalsDs data_con_arg_tys `thenDs` \ vars@[ixs_var, arr_cts_var] ->
+ = 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 (AlgAlts [(the_data_con,vars,body)]
- NoDefault)
+ \ 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 the_prim_arg_ty `thenDs` \ prim_arg ->
+ = newSysLocalDs arg_ty `thenDs` \ case_bndr ->
+ newSysLocalDs the_prim_arg_ty `thenDs` \ prim_arg ->
returnDs (Var prim_arg,
- \ body -> Case arg (AlgAlts [(box_data_con,[prim_arg],body)]
- NoDefault)
+ \ body -> Case arg case_bndr [(DataAlt box_data_con,[prim_arg],body)]
)
| otherwise
= getSrcLocDs `thenDs` \ l ->
pprPanic "unboxArg: " (ppr l <+> ppr arg_ty)
where
- arg_ty = coreExprType arg
+ 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_data_type = splitAlgTyConApp_maybe arg_ty
- is_data_type = maybeToBool maybe_data_type
- (Just (tycon, tycon_arg_tys, data_cons)) = maybe_data_type
- (the_data_con : other_data_cons) = data_cons
+ 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
- data_con_arg_tys = dataConArgTys the_data_con tycon_arg_tys
- (data_con_arg_ty1 : data_con_arg_ty2 : _) = data_con_arg_tys
+ maybe_arg3_tycon = splitTyConApp_maybe data_con_arg_ty3
+ Just (arg3_tycon,_) = maybe_arg3_tycon
- maybe_arg2_tycon = splitTyConApp_maybe data_con_arg_ty2
- Just (arg2_tycon,_) = maybe_arg2_tycon
-
-can't_see_datacons_error thing ty
- = pprPanic "ERROR: Can't see the data constructor(s) for _ccall_/_casm_ "
- (hcat [text thing, text "; type: ", ppr ty, text "(try compiling with -fno-prune-tydecls ..)\n"])
+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"])
\end{code}
\begin{code}
-boxResult :: Id -- IOok constructor
- -> Type -- Type of desired result
+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 ioOkDataCon result_ty
- | null data_cons
- -- oops! can't see the data constructors
- = can't_see_datacons_error "result" result_ty
-
- -- Data types with a single constructor, which has a single, primitive-typed arg
- | (maybeToBool maybe_data_type) && -- Data type
- (null other_data_cons) && -- Just one constr
- not (null data_con_arg_tys) && null other_args_tys && -- Just one arg
- isUnpointedType the_prim_result_ty -- of primitive type
+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 ->
- newSysLocalDs the_prim_result_ty `thenDs` \ prim_result_id ->
-
- mkConDs the_data_con (map TyArg tycon_arg_tys ++ [VarArg (Var prim_result_id)]) `thenDs` \ the_result ->
-
+{-
+ 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_alt = (state_and_prim_datacon, [prim_state_id, prim_result_id], the_pair)
+ 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 (state_and_prim_ty,
- \prim_app -> Case prim_app (AlgAlts [the_alt] NoDefault)
+ returnDs (scrut_ty, \prim_app -> Case prim_app (mkWildId scrut_ty) [the_alt]
)
- -- Data types with a single nullary constructor
- | (maybeToBool maybe_data_type) && -- Data type
- (null other_data_cons) && -- Just one constr
- (null data_con_arg_tys)
+ -- 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 ->
-
- mkConDs ioOkDataCon
- [TyArg result_ty, VarArg (Var prim_state_id), VarArg (Var unitDataCon)]
- `thenDs` \ the_pair ->
+ newSysLocalDs the_prim_result_ty `thenDs` \ prim_result_id ->
+ newSysLocalDs ccall_res_type `thenDs` \ case_bndr ->
let
- the_alt = (stateDataCon, [prim_state_id], the_pair)
+ 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 (realWorldStateTy,
- \prim_app -> Case prim_app (AlgAlts [the_alt] NoDefault)
+ returnDs (ccall_res_type, \prim_app -> Case prim_app case_bndr [the_alt]
)
| otherwise
= pprPanic "boxResult: " (ppr result_ty)
-
where
- maybe_data_type = splitAlgTyConApp_maybe result_ty
- Just (tycon, tycon_arg_tys, data_cons) = maybe_data_type
- (the_data_con : other_data_cons) = data_cons
-
- data_con_arg_tys = dataConArgTys the_data_con tycon_arg_tys
- (the_prim_result_ty : other_args_tys) = data_con_arg_tys
+ 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
- (state_and_prim_datacon, state_and_prim_ty) = getStatePairingConInfo the_prim_result_ty
-\end{code}
+ ccall_res_type = mkUnboxedTupleTy 2 [realWorldStatePrimTy, the_prim_result_ty]
-This grimy bit of code is for digging out the IOok constructor from an
-application of the the IO type. The constructor is needed for
-wrapping the result of a _ccall_. The alternative is to wire-in IO,
-which brings a whole heap of junk with it.
-
-If the representation of IO changes, this will probably have to be
-brought in line with the new definition.
-
-newtype IO a = IO (State# RealWorld -> IOResult a)
-
-the constructor IO has type (State# RealWorld -> IOResult a) -> IO a
-
-\begin{code}
-getIoOkDataCon :: Type -- IO t
- -> (Id,Type) -- Returns (IOok, t)
-
-getIoOkDataCon io_ty
- = let
- Just (ioTyCon, [t]) = splitTyConApp_maybe io_ty
- [ioDataCon] = tyConDataCons ioTyCon
- ioDataConTy = idType ioDataCon
- (_, ioDataConTy') = splitForAllTys ioDataConTy
- ([arg_ty], _) = splitFunTys ioDataConTy'
- (_, io_result_ty) = splitFunTys arg_ty
- Just (io_result_tycon, _) = splitTyConApp_maybe io_result_ty
- [ioOkDataCon,ioFailDataCon] = tyConDataCons io_result_tycon
+-- 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])
in
- (ioOkDataCon, t)
-\end{code}
+ returnDs (ccall_res_type, prim_result_id, the_result)
-Another way to do it, more sensitive:
+ -- 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)
- case ioDataConTy of
- ForAll _ (FunTy (FunTy _ (AppTy (TyConTy ioResultTyCon _) _)) _) ->
- let [ioOkDataCon,ioFailDataCon] = tyConDataCons ioResultTyCon
- in
- (ioOkDataCon, result_ty)
- _ -> pprPanic "getIoOkDataCon: " (ppr PprDebug ioDataConTy)
+ | 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]
+\end{code}