%
-% (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}
-#include "HsVersions.h"
-
-module DsCCall ( dsCCall ) where
+module DsCCall
+ ( dsCCall
+ , mkFCall
+ , unboxArg
+ , boxResult
+ , resultWrapper
+ ) where
-IMP_Ubiq()
+#include "HsVersions.h"
import CoreSyn
import DsMonad
-import DsUtils
-import CoreUtils ( coreExprType )
-import Id ( dataConArgTys )
+import CoreUtils ( exprType, mkCoerce2 )
+import Id ( Id, mkWildId )
+import MkId ( mkFCallId, realWorldPrimId, mkPrimOpId )
import Maybes ( maybeToBool )
-import PprStyle ( PprStyle(..) )
-import PprType ( GenType{-instances-} )
-import Pretty
-import PrelVals ( packStringForCId )
+import ForeignCall ( ForeignCall(..), CCallSpec(..), CCallTarget(..), Safety, CCallConv(..) )
+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, splitNewType_maybe
+ )
+
import PrimOp ( PrimOp(..) )
-import Type ( isPrimType, maybeAppDataTyConExpandingDicts, maybeAppTyCon,
- eqTy, maybeBoxedPrimType )
-import TysPrim ( byteArrayPrimTy, realWorldTy, realWorldStatePrimTy,
- byteArrayPrimTyCon, mutableByteArrayPrimTyCon )
-import TysWiredIn ( getStatePairingConInfo,
- realWorldStateTy, stateDataCon, pairDataCon, unitDataCon,
- stringTy
+import TysPrim ( realWorldStatePrimTy, intPrimTy,
+ byteArrayPrimTyCon, mutableByteArrayPrimTyCon
+ )
+import TyCon ( TyCon, tyConDataCons )
+import TysWiredIn ( unitDataConId,
+ unboxedSingletonDataCon, unboxedPairDataCon,
+ unboxedSingletonTyCon, unboxedPairTyCon,
+ trueDataCon, falseDataCon,
+ trueDataConId, falseDataConId
)
-import Util ( pprPanic, pprError, panic )
+import Literal ( mkMachInt )
+import CStrings ( CLabelString )
+import PrelNames ( Unique, hasKey, ioTyConKey, boolTyConKey, unitTyConKey,
+ int8TyConKey, int16TyConKey, int32TyConKey,
+ word8TyConKey, word16TyConKey, word32TyConKey
+ )
+import VarSet ( varSetElems )
+import Constants ( wORD_SIZE)
+import Outputable
\end{code}
Desugaring of @ccall@s consists of adding some state manipulation,
\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
+ -> Safety -- Safety of the call
-> Bool -- True <=> really a "_casm_"
- -> Type -- Type of the result (a boxed-prim type)
+ -> Type -- Type of the result: IO t
-> DsM CoreExpr
-dsCCall label args may_gc is_asm result_ty
- = newSysLocalDs realWorldStateTy `thenDs` \ old_s ->
-
- mapAndUnzipDs unboxArg (Var old_s : args) `thenDs` \ (final_args, arg_wrappers) ->
-
- boxResult result_ty `thenDs` \ (final_result_ty, res_wrapper) ->
-
+dsCCall lbl args may_gc is_asm result_ty
+ = mapAndUnzipDs unboxArg args `thenDs` \ (unboxed_args, arg_wrappers) ->
+ boxResult [] result_ty `thenDs` \ (ccall_result_ty, res_wrapper) ->
+ getUniqueDs `thenDs` \ uniq ->
let
- the_ccall_op = CCallOp label is_asm may_gc
- (map coreExprType final_args)
- final_result_ty
+ target | is_asm = CasmTarget lbl
+ | otherwise = StaticTarget lbl
+ the_fcall = CCall (CCallSpec target CCallConv may_gc)
+ the_prim_app = mkFCall uniq the_fcall unboxed_args ccall_result_ty
in
- mkPrimDs the_ccall_op (map VarArg final_args) `thenDs` \ the_prim_app ->
- let
- the_body = foldr ($) (res_wrapper the_prim_app) arg_wrappers
- in
- returnDs (Lam (ValBinder old_s) the_body)
+ returnDs (foldr ($) (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}
-> 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 :-)
- --
- | isPrimType arg_ty
+unboxArg arg
+ -- Primtive types: nothing to unbox
+ | isPrimitiveType arg_ty
= returnDs (arg, \body -> body)
- -- Strings
- | arg_ty `eqTy` stringTy
- -- ToDo (ADR): - allow synonyms of Strings too?
- = newSysLocalDs byteArrayPrimTy `thenDs` \ prim_arg ->
- mkAppDs (Var packStringForCId) [VarArg arg] `thenDs` \ pack_appn ->
+ -- Recursive newtypes
+ | Just rep_ty <- splitNewType_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 pack_appn (PrimAlts []
- (BindDefault prim_arg body))
- )
+ \ body -> Case (Case arg (mkWildId arg_ty)
+ [(DataAlt falseDataCon,[],mkIntLit 0),
+ (DataAlt trueDataCon, [],mkIntLit 1)])
+ prim_arg
+ [(DEFAULT,[],body)])
- | null data_cons
- -- oops: we can't see the data constructors!!!
- = can't_see_datacons_error "argument" arg_ty
+ -- Data types with a single constructor, which has a single, primitive-typed arg
+ -- This deals with Int, Float etc
+ | is_product_type && data_con_arity == 1
+ = ASSERT(isUnLiftedType data_con_arg_ty1 ) -- 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
- | is_data_type &&
- length data_con_arg_tys == 2 &&
- maybeToBool maybe_arg2_tycon &&
- (arg2_tycon == byteArrayPrimTyCon ||
- arg2_tycon == mutableByteArrayPrimTyCon)
+ -- 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)
-- 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)
- )
-
- -- 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 ->
- returnDs (Var prim_arg,
- \ body -> Case arg (AlgAlts [(box_data_con,[prim_arg],body)]
- NoDefault)
+ \ body -> Case arg case_bndr [(DataAlt data_con,vars,body)]
)
| otherwise
- = pprPanic "unboxArg: " (ppr PprDebug arg_ty)
+ = getSrcLocDs `thenDs` \ l ->
+ pprPanic "unboxArg: " (ppr l <+> ppr arg_ty)
where
- arg_ty = coreExprType 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 = maybeAppDataTyConExpandingDicts 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
-
- data_con_arg_tys = dataConArgTys the_data_con tycon_arg_tys
- (data_con_arg_ty1 : data_con_arg_ty2 : _) = data_con_arg_tys
-
- maybe_arg2_tycon = maybeAppTyCon data_con_arg_ty2
- Just (arg2_tycon,_) = maybe_arg2_tycon
-
-can't_see_datacons_error thing ty
- = pprError "ERROR: Can't see the data constructor(s) for _ccall_/_casm_ "
- (ppBesides [ppStr thing, ppStr "; type: ", ppr PprForUser ty])
+ 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
- | 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
- isPrimType the_prim_result_ty -- of primitive type
- =
- newSysLocalDs realWorldStatePrimTy `thenDs` \ prim_state_id ->
- newSysLocalDs the_prim_result_ty `thenDs` \ prim_result_id ->
-
- mkConDs stateDataCon [TyArg realWorldTy, VarArg (Var prim_state_id)] `thenDs` \ new_state ->
- mkConDs the_data_con (map TyArg tycon_arg_tys ++ [VarArg (Var prim_result_id)]) `thenDs` \ the_result ->
-
- mkConDs pairDataCon
- [TyArg result_ty, TyArg realWorldStateTy, VarArg the_result, VarArg new_state]
- `thenDs` \ the_pair ->
- let
- the_alt = (state_and_prim_datacon, [prim_state_id, prim_result_id], the_pair)
+boxResult :: [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 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
+ -> mk_alt return_result
+ (resultWrapper io_res_ty) `thenDs` \ (ccall_res_ty, the_alt) ->
+ newSysLocalDs realWorldStatePrimTy `thenDs` \ state_id ->
+ let
+ io_data_con = head (tyConDataCons io_tycon)
+ wrap = \ the_call ->
+ mkApps (Var (dataConWrapId io_data_con))
+ [ 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 state ans = mkConApp unboxedPairDataCon
+ [Type realWorldStatePrimTy, Type io_res_ty,
+ state, ans]
+
+ -- It isn't, so do unsafePerformIO
+ -- It's not conveniently available, so we inline it
+ other -> mk_alt return_result
+ (resultWrapper result_ty) `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
+ 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
+ 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
+ -> (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
+ = (Just result_ty, \e -> e)
+
+ -- Base case 2: the unit type ()
+ | Just (tc,_) <- maybe_tc_app, tc `hasKey` unitTyConKey
+ = (Nothing, \e -> Var unitDataConId)
+
+ -- Base case 3: the boolean type
+ | Just (tc,_) <- maybe_tc_app, tc `hasKey` boolTyConKey
+ = (Just intPrimTy, \e -> Case e (mkWildId intPrimTy)
+ [(DEFAULT ,[],Var trueDataConId ),
+ (LitAlt (mkMachInt 0),[],Var falseDataConId)])
+
+ -- Recursive newtypes
+ | Just rep_ty <- splitNewType_maybe result_ty
+ = let
+ (maybe_ty, wrapper) = resultWrapper rep_ty
in
- returnDs (state_and_prim_ty,
- \prim_app -> Case prim_app (AlgAlts [the_alt] NoDefault)
- )
-
- -- 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)
- =
- newSysLocalDs realWorldStatePrimTy `thenDs` \ prim_state_id ->
-
- mkConDs stateDataCon [TyArg realWorldTy, VarArg (Var prim_state_id)]
- `thenDs` \ new_state ->
- mkConDs pairDataCon
- [TyArg result_ty, TyArg realWorldStateTy, VarArg (Var unitDataCon), VarArg new_state]
- `thenDs` \ the_pair ->
-
- let
- the_alt = (stateDataCon, [prim_state_id], the_pair)
+ (maybe_ty, \e -> mkCoerce2 result_ty rep_ty (wrapper e))
+
+ -- Data types with a single constructor, which has a single arg
+ | Just (tycon, tycon_arg_tys, data_con, data_con_arg_tys) <- splitProductType_maybe result_ty,
+ dataConSourceArity data_con == 1
+ = let
+ (maybe_ty, wrapper) = resultWrapper unwrapped_res_ty
+ (unwrapped_res_ty : _) = data_con_arg_tys
+ narrow_wrapper = maybeNarrow tycon
in
- returnDs (realWorldStateTy,
- \prim_app -> Case prim_app (AlgAlts [the_alt] NoDefault)
- )
+ (maybe_ty, \e -> mkApps (Var (dataConWrapId data_con))
+ (map Type tycon_arg_tys ++ [wrapper (narrow_wrapper e)]))
| otherwise
- = pprPanic "boxResult: " (ppr PprDebug result_ty)
-
+ = pprPanic "resultWrapper" (ppr result_ty)
where
- maybe_data_type = maybeAppDataTyConExpandingDicts 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
-
- (state_and_prim_datacon, state_and_prim_ty) = getStatePairingConInfo the_prim_result_ty
+ 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}
-
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