%
-% (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
- , getIoOkDataCon
- , unboxArg
- , boxResult
+ ( dsCCall
+ , unboxArg
+ , boxResult
, wrapUnboxedValue
- , can'tSeeDataConsPanic
+ , can'tSeeDataConsPanic
+
) where
#include "HsVersions.h"
import TcHsSyn ( maybeBoxedPrimType )
import CoreUtils ( coreExprType )
-import Id ( Id, dataConArgTys, idType )
+import Id ( Id, mkWildId )
+import Const ( Con(..) )
import Maybes ( maybeToBool )
-import PrelVals ( packStringForCId )
+import PrelInfo ( packStringForCId )
import PrimOp ( PrimOp(..) )
+import DataCon ( DataCon, dataConId, dataConArgTys )
import CallConv
-import Type ( isUnpointedType, splitAlgTyConApp_maybe,
- splitTyConApp_maybe, splitFunTys, splitForAllTys,
- Type
+import Type ( isUnLiftedType, splitAlgTyConApp_maybe, mkFunTys,
+ splitTyConApp_maybe, Type
)
-import TyCon ( tyConDataCons )
import TysPrim ( byteArrayPrimTy, realWorldStatePrimTy,
byteArrayPrimTyCon, mutableByteArrayPrimTyCon )
-import TysWiredIn ( getStatePairingConInfo,
- unitDataCon, stringTy,
- realWorldStateTy, stateDataCon
+import TysWiredIn ( unitDataCon, stringTy,
+ mkUnboxedTupleTy, unboxedPairDataCon,
+ mkUnboxedTupleTy, unboxedTupleCon
)
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 label 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) ->
+
let
- final_args = Var old_s : unboxed_args
- (ioOkDataCon, _, result_ty) = getIoOkDataCon io_result_ty
- in
+ val_args = Var old_s : unboxed_args
+ final_args = Type inst_ty : val_args
- boxResult ioOkDataCon result_ty `thenDs` \ (final_result_ty, res_wrapper) ->
+ -- A CCallOp has type (forall a. a), so we must instantiate
+ -- it at the full type, including the state argument
+ inst_ty = mkFunTys (map coreExprType val_args) final_result_ty
- let
the_ccall_op = CCallOp (Left label) is_asm may_gc cCallConv
- (map coreExprType final_args)
- final_result_ty
- in
- mkPrimDs the_ccall_op (map VarArg final_args) `thenDs` \ the_prim_app ->
- let
+ the_prim_app = mkPrimApp the_ccall_op final_args
+
the_body = foldr ($) (res_wrapper the_prim_app) arg_wrappers
in
- returnDs (Lam (ValBinder old_s) the_body)
+ returnDs (Lam old_s the_body)
\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))
- )
+ \body -> Case (App (Var packStringForCId) arg)
+ prim_arg [(DEFAULT,[],body)])
| null data_cons
-- oops: we can't see the data constructors!!!
(arg2_tycon == byteArrayPrimTyCon ||
arg2_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@[ixs_var, arr_cts_var] ->
returnDs (Var arr_cts_var,
- \ body -> Case arg (AlgAlts [(the_data_con,vars,body)]
- NoDefault)
+ \ body -> Case arg case_bndr [(DataCon the_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 [(DataCon box_data_con,[prim_arg],body)]
)
| otherwise
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
+boxResult result_ty
| null data_cons
-- oops! can't see the data constructors
= can'tSeeDataConsPanic "result" result_ty
- -- Data types with a single constructor, which has a single, primitive-typed arg
+ -- Data types with a single nullary constructor
| (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
+ (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_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,
+ Con (DataCon unitDataCon) []]
+ the_alt = (DataCon (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
+ -- 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
- (null data_con_arg_tys)
+ 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 the_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 = (DataCon 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
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
+ ccall_res_type = mkUnboxedTupleTy 2
+ [realWorldStatePrimTy, the_prim_result_ty]
data_con_arg_tys = dataConArgTys the_data_con tycon_arg_tys
(the_prim_result_ty : other_args_tys) = data_con_arg_tys
--- (state_and_prim_datacon, state_and_prim_ty) = getStatePairingConInfo the_prim_result_ty
-
-- wrap up an unboxed value.
-wrapUnboxedValue :: Type -> DsM (Id, Type, Id, CoreExpr)
+wrapUnboxedValue :: Type -> DsM (Type, Id, CoreExpr)
wrapUnboxedValue ty
| null data_cons
-- oops! can't see the data constructors
| (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
+ isUnLiftedType the_prim_result_ty -- of primitive type
=
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 ->
- returnDs (state_and_prim_datacon, state_and_prim_ty, prim_result_id, the_result)
+ let
+ the_result = mkConApp the_data_con (map Type tycon_arg_tys ++ [Var prim_result_id])
+ in
+ returnDs (ccall_res_type, prim_result_id, the_result)
-- 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)
=
- let unit = unitDataCon in
- returnDs (stateDataCon, realWorldStateTy, unit, Var unit)
+ let unit = dataConId unitDataCon
+ scrut_ty = mkUnboxedTupleTy 1 [realWorldStatePrimTy]
+ in
+ returnDs (scrut_ty, unit, mkConApp unitDataCon [])
| otherwise
= pprPanic "boxResult: " (ppr ty)
where
maybe_data_type = splitAlgTyConApp_maybe ty
Just (tycon, tycon_arg_tys, data_cons) = maybe_data_type
(the_data_con : other_data_cons) = data_cons
+ ccall_res_type = mkUnboxedTupleTy 2
+ [realWorldStatePrimTy, the_prim_result_ty]
data_con_arg_tys = dataConArgTys the_data_con tycon_arg_tys
(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}
-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, Id, Type) -- Returns (IOok, IO, 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
- in
- (ioOkDataCon, ioDataCon, t)
\end{code}
-
-Another way to do it, more sensitive:
-
- case ioDataConTy of
- ForAll _ (FunTy (FunTy _ (AppTy (TyConTy ioResultTyCon _) _)) _) ->
- let [ioOkDataCon,ioFailDataCon] = tyConDataCons ioResultTyCon
- in
- (ioOkDataCon, result_ty)
- _ -> pprPanic "getIoOkDataCon: " (ppr PprDebug ioDataConTy)
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