2 % (c) The AQUA Project, Glasgow University, 1994-1998
4 \section[DsCCall]{Desugaring \tr{_ccall_}s and \tr{_casm_}s}
15 #include "HsVersions.h"
21 import CoreUtils ( exprType, mkCoerce2 )
22 import Id ( Id, mkWildId )
23 import MkId ( mkFCallId, realWorldPrimId, mkPrimOpId )
24 import Maybes ( maybeToBool )
25 import ForeignCall ( ForeignCall(..), CCallSpec(..), CCallTarget(..), Safety, CCallConv(..) )
26 import DataCon ( splitProductType_maybe, dataConSourceArity, dataConWrapId )
27 import ForeignCall ( ForeignCall, CCallTarget(..) )
29 import TcType ( tcSplitTyConApp_maybe )
30 import Type ( Type, isUnLiftedType, mkFunTys, mkFunTy,
31 tyVarsOfType, mkForAllTys, mkTyConApp,
32 isPrimitiveType, splitTyConApp_maybe,
33 splitNewType_maybe, splitForAllTy_maybe,
37 import PrimOp ( PrimOp(..) )
38 import TysPrim ( realWorldStatePrimTy, intPrimTy,
39 byteArrayPrimTyCon, mutableByteArrayPrimTyCon,
42 import TyCon ( TyCon, tyConDataCons, tyConName )
43 import TysWiredIn ( unitDataConId,
44 unboxedSingletonDataCon, unboxedPairDataCon,
45 unboxedSingletonTyCon, unboxedPairTyCon,
46 trueDataCon, falseDataCon,
47 trueDataConId, falseDataConId,
51 import BasicTypes ( Boxity(..) )
52 import Literal ( mkMachInt )
53 import CStrings ( CLabelString )
54 import PrelNames ( Unique, hasKey, ioTyConKey, boolTyConKey, unitTyConKey,
55 int8TyConKey, int16TyConKey, int32TyConKey,
56 word8TyConKey, word16TyConKey, word32TyConKey
58 , marshalStringName, unmarshalStringName
59 , marshalObjectName, unmarshalObjectName
62 import VarSet ( varSetElems )
63 import Constants ( wORD_SIZE)
67 Desugaring of @ccall@s consists of adding some state manipulation,
68 unboxing any boxed primitive arguments and boxing the result if
71 The state stuff just consists of adding in
72 @PrimIO (\ s -> case s of { S# s# -> ... })@ in an appropriate place.
74 The unboxing is straightforward, as all information needed to unbox is
75 available from the type. For each boxed-primitive argument, we
78 _ccall_ foo [ r, t1, ... tm ] e1 ... em
82 case e1 of { T1# x1# ->
84 case em of { Tm# xm# -> xm#
85 ccall# foo [ r, t1#, ... tm# ] x1# ... xm#
89 The reboxing of a @_ccall_@ result is a bit tricker: the types don't
90 contain information about the state-pairing functions so we have to
91 keep a list of \tr{(type, s-p-function)} pairs. We transform as
94 ccall# foo [ r, t1#, ... tm# ] e1# ... em#
98 \ s# -> case (ccall# foo [ r, t1#, ... tm# ] s# e1# ... em#) of
99 (StateAnd<r># result# state#) -> (R# result#, realWorld#)
103 dsCCall :: CLabelString -- C routine to invoke
104 -> [CoreExpr] -- Arguments (desugared)
105 -> Safety -- Safety of the call
106 -> Bool -- True <=> really a "_casm_"
107 -> Type -- Type of the result: IO t
110 dsCCall lbl args may_gc is_asm result_ty
111 = mapAndUnzipDs unboxArg args `thenDs` \ (unboxed_args, arg_wrappers) ->
112 boxResult [] id Nothing result_ty `thenDs` \ (ccall_result_ty, res_wrapper) ->
113 getUniqueDs `thenDs` \ uniq ->
115 target | is_asm = CasmTarget lbl
116 | otherwise = StaticTarget lbl
117 the_fcall = CCall (CCallSpec target CCallConv may_gc)
118 the_prim_app = mkFCall uniq the_fcall unboxed_args ccall_result_ty
120 returnDs (foldr ($) (res_wrapper the_prim_app) arg_wrappers)
122 mkFCall :: Unique -> ForeignCall
123 -> [CoreExpr] -- Args
124 -> Type -- Result type
126 -- Construct the ccall. The only tricky bit is that the ccall Id should have
127 -- no free vars, so if any of the arg tys do we must give it a polymorphic type.
128 -- [I forget *why* it should have no free vars!]
130 -- mkCCall ... [s::StablePtr (a->b), x::Addr, c::Char]
132 -- Here we build a ccall thus
133 -- (ccallid::(forall a b. StablePtr (a -> b) -> Addr -> Char -> IO Addr))
135 mkFCall uniq the_fcall val_args res_ty
136 = mkApps (mkVarApps (Var the_fcall_id) tyvars) val_args
138 arg_tys = map exprType val_args
139 body_ty = (mkFunTys arg_tys res_ty)
140 tyvars = varSetElems (tyVarsOfType body_ty)
141 ty = mkForAllTys tyvars body_ty
142 the_fcall_id = mkFCallId uniq the_fcall ty
146 unboxArg :: CoreExpr -- The supplied argument
147 -> DsM (CoreExpr, -- To pass as the actual argument
148 CoreExpr -> CoreExpr -- Wrapper to unbox the arg
150 -- Example: if the arg is e::Int, unboxArg will return
151 -- (x#::Int#, \W. case x of I# x# -> W)
152 -- where W is a CoreExpr that probably mentions x#
155 -- Primtive types: nothing to unbox
156 | isPrimitiveType arg_ty
157 = returnDs (arg, \body -> body)
159 -- Recursive newtypes
160 | Just rep_ty <- splitNewType_maybe arg_ty
161 = unboxArg (mkCoerce2 rep_ty arg_ty arg)
164 | Just (tc,_) <- splitTyConApp_maybe arg_ty,
165 tc `hasKey` boolTyConKey
166 = newSysLocalDs intPrimTy `thenDs` \ prim_arg ->
167 returnDs (Var prim_arg,
168 \ body -> Case (Case arg (mkWildId arg_ty)
169 [(DataAlt falseDataCon,[],mkIntLit 0),
170 (DataAlt trueDataCon, [],mkIntLit 1)])
174 -- Data types with a single constructor, which has a single, primitive-typed arg
175 -- This deals with Int, Float etc; also Ptr, ForeignPtr
176 | is_product_type && data_con_arity == 1
177 = ASSERT(isUnLiftedType data_con_arg_ty1 ) -- Typechecker ensures this
178 newSysLocalDs arg_ty `thenDs` \ case_bndr ->
179 newSysLocalDs data_con_arg_ty1 `thenDs` \ prim_arg ->
180 returnDs (Var prim_arg,
181 \ body -> Case arg case_bndr [(DataAlt data_con,[prim_arg],body)]
184 -- Byte-arrays, both mutable and otherwise; hack warning
185 -- We're looking for values of type ByteArray, MutableByteArray
186 -- data ByteArray ix = ByteArray ix ix ByteArray#
187 -- data MutableByteArray s ix = MutableByteArray ix ix (MutableByteArray# s)
189 data_con_arity == 3 &&
190 maybeToBool maybe_arg3_tycon &&
191 (arg3_tycon == byteArrayPrimTyCon ||
192 arg3_tycon == mutableByteArrayPrimTyCon)
193 -- and, of course, it is an instance of CCallable
194 = newSysLocalDs arg_ty `thenDs` \ case_bndr ->
195 newSysLocalsDs data_con_arg_tys `thenDs` \ vars@[l_var, r_var, arr_cts_var] ->
196 returnDs (Var arr_cts_var,
197 \ body -> Case arg case_bndr [(DataAlt data_con,vars,body)]
200 | Just (tc, [arg_ty]) <- splitTyConApp_maybe arg_ty,
202 Just (cc,[]) <- splitTyConApp_maybe arg_ty,
204 -- String; dotnet only
205 = dsLookupGlobalId marshalStringName `thenDs` \ unpack_id ->
206 newSysLocalDs addrPrimTy `thenDs` \ prim_string ->
207 returnDs (Var prim_string,
210 io_ty = exprType body
211 (Just (_,[io_arg])) = tcSplitTyConApp_maybe io_ty
213 mkApps (Var unpack_id)
216 , Lam prim_string body
218 | Just (tc, [arg_ty]) <- splitTyConApp_maybe arg_ty,
219 tyConName tc == objectTyConName
220 -- Object; dotnet only
221 = dsLookupGlobalId marshalObjectName `thenDs` \ unpack_id ->
222 newSysLocalDs addrPrimTy `thenDs` \ prim_obj ->
223 returnDs (Var prim_obj,
226 io_ty = exprType body
227 (Just (_,[io_arg])) = tcSplitTyConApp_maybe io_ty
229 mkApps (Var unpack_id)
236 = getSrcLocDs `thenDs` \ l ->
237 pprPanic "unboxArg: " (ppr l <+> ppr arg_ty)
239 arg_ty = exprType arg
240 maybe_product_type = splitProductType_maybe arg_ty
241 is_product_type = maybeToBool maybe_product_type
242 Just (_, _, data_con, data_con_arg_tys) = maybe_product_type
243 data_con_arity = dataConSourceArity data_con
244 (data_con_arg_ty1 : _) = data_con_arg_tys
246 (_ : _ : data_con_arg_ty3 : _) = data_con_arg_tys
247 maybe_arg3_tycon = splitTyConApp_maybe data_con_arg_ty3
248 Just (arg3_tycon,_) = maybe_arg3_tycon
254 -> ((Maybe Type, CoreExpr -> CoreExpr) -> (Maybe Type, CoreExpr -> CoreExpr))
257 -> DsM (Type, CoreExpr -> CoreExpr)
259 -- Takes the result of the user-level ccall:
261 -- or maybe just t for an side-effect-free call
262 -- Returns a wrapper for the primitive ccall itself, along with the
263 -- type of the result of the primitive ccall. This result type
264 -- will be of the form
265 -- State# RealWorld -> (# State# RealWorld, t' #)
266 -- where t' is the unwrapped form of t. If t is simply (), then
267 -- the result type will be
268 -- State# RealWorld -> (# State# RealWorld #)
270 boxResult arg_ids augment mbTopCon result_ty
271 = case tcSplitTyConApp_maybe result_ty of
272 -- This split absolutely has to be a tcSplit, because we must
273 -- see the IO type; and it's a newtype which is transparent to splitTyConApp.
275 -- The result is IO t, so wrap the result in an IO constructor
276 Just (io_tycon, [io_res_ty]) | io_tycon `hasKey` ioTyConKey
277 -> resultWrapper io_res_ty `thenDs` \ res ->
278 let aug_res = augment res
282 | isUnboxedTupleType ty ->
283 let (Just (_, ls)) = splitTyConApp_maybe ty in tail ls
286 mk_alt (return_result extra_result_tys) aug_res
287 `thenDs` \ (ccall_res_ty, the_alt) ->
288 newSysLocalDs realWorldStatePrimTy `thenDs` \ state_id ->
290 io_data_con = head (tyConDataCons io_tycon)
293 Nothing -> dataConWrapId io_data_con
299 Case (App the_call (Var state_id))
300 (mkWildId ccall_res_ty)
304 returnDs (realWorldStatePrimTy `mkFunTy` ccall_res_ty, wrap)
306 return_result ts state anss
307 = mkConApp (tupleCon Unboxed (2 + length ts))
308 (Type realWorldStatePrimTy : Type io_res_ty : map Type ts ++
310 -- It isn't, so do unsafePerformIO
311 -- It's not conveniently available, so we inline it
312 other -> resultWrapper result_ty `thenDs` \ res ->
313 mk_alt return_result (augment res) `thenDs` \ (ccall_res_ty, the_alt) ->
315 wrap = \ the_call -> Case (App the_call (Var realWorldPrimId))
316 (mkWildId ccall_res_ty)
319 returnDs (realWorldStatePrimTy `mkFunTy` ccall_res_ty, wrap)
321 return_result state [ans] = ans
322 return_result _ _ = panic "return_result: expected single result"
324 mk_alt return_result (Nothing, wrap_result)
325 = -- The ccall returns ()
326 newSysLocalDs realWorldStatePrimTy `thenDs` \ state_id ->
328 the_rhs = return_result (Var state_id)
329 [wrap_result (panic "boxResult")]
331 ccall_res_ty = mkTyConApp unboxedSingletonTyCon [realWorldStatePrimTy]
332 the_alt = (DataAlt unboxedSingletonDataCon, [state_id], the_rhs)
334 returnDs (ccall_res_ty, the_alt)
336 mk_alt return_result (Just prim_res_ty, wrap_result)
337 -- The ccall returns a non-() value
338 | isUnboxedTupleType prim_res_ty
340 (Just (_, ls@(prim_res_ty1:extras))) = splitTyConApp_maybe prim_res_ty
341 arity = 1 + length ls
343 mapDs newSysLocalDs ls `thenDs` \ args_ids@(result_id:as) ->
344 newSysLocalDs realWorldStatePrimTy `thenDs` \ state_id ->
346 the_rhs = return_result (Var state_id)
347 (wrap_result (Var result_id) : map Var as)
348 ccall_res_ty = mkTyConApp (tupleTyCon Unboxed arity)
349 (realWorldStatePrimTy : ls)
350 the_alt = ( DataAlt (tupleCon Unboxed arity)
351 , (state_id : args_ids)
355 returnDs (ccall_res_ty, the_alt)
358 newSysLocalDs prim_res_ty `thenDs` \ result_id ->
359 newSysLocalDs realWorldStatePrimTy `thenDs` \ state_id ->
361 the_rhs = return_result (Var state_id)
362 [wrap_result (Var result_id)]
364 ccall_res_ty = mkTyConApp unboxedPairTyCon [realWorldStatePrimTy, prim_res_ty]
365 the_alt = (DataAlt unboxedPairDataCon, [state_id, result_id], the_rhs)
367 returnDs (ccall_res_ty, the_alt)
370 resultWrapper :: Type
371 -> DsM (Maybe Type, -- Type of the expected result, if any
372 CoreExpr -> CoreExpr) -- Wrapper for the result
373 resultWrapper result_ty
374 -- Base case 1: primitive types
375 | isPrimitiveType result_ty
376 = returnDs (Just result_ty, \e -> e)
378 -- Base case 2: the unit type ()
379 | Just (tc,_) <- maybe_tc_app, tc `hasKey` unitTyConKey
380 = returnDs (Nothing, \e -> Var unitDataConId)
382 -- Base case 3: the boolean type
383 | Just (tc,_) <- maybe_tc_app, tc `hasKey` boolTyConKey
385 (Just intPrimTy, \e -> Case e (mkWildId intPrimTy)
386 [(DEFAULT ,[],Var trueDataConId ),
387 (LitAlt (mkMachInt 0),[],Var falseDataConId)])
389 -- Recursive newtypes
390 | Just rep_ty <- splitNewType_maybe result_ty
391 = resultWrapper rep_ty `thenDs` \ (maybe_ty, wrapper) ->
392 returnDs (maybe_ty, \e -> mkCoerce2 result_ty rep_ty (wrapper e))
394 -- The type might contain foralls (eg. for dummy type arguments,
395 -- referring to 'Ptr a' is legal).
396 | Just (tyvar, rest) <- splitForAllTy_maybe result_ty
397 = resultWrapper rest `thenDs` \ (maybe_ty, wrapper) ->
398 returnDs (maybe_ty, \e -> Lam tyvar (wrapper e))
400 -- Data types with a single constructor, which has a single arg
401 -- This includes types like Ptr and ForeignPtr
402 | Just (tycon, tycon_arg_tys, data_con, data_con_arg_tys) <- splitProductType_maybe result_ty,
403 dataConSourceArity data_con == 1
405 (unwrapped_res_ty : _) = data_con_arg_tys
406 narrow_wrapper = maybeNarrow tycon
408 resultWrapper unwrapped_res_ty `thenDs` \ (maybe_ty, wrapper) ->
410 (maybe_ty, \e -> mkApps (Var (dataConWrapId data_con))
411 (map Type tycon_arg_tys ++ [wrapper (narrow_wrapper e)]))
413 -- Strings; 'dotnet' only.
414 | Just (tc, [arg_ty]) <- maybe_tc_app, tc == listTyCon,
415 Just (cc,[]) <- splitTyConApp_maybe arg_ty, cc == charTyCon
416 = dsLookupGlobalId unmarshalStringName `thenDs` \ pack_id ->
417 returnDs (Just addrPrimTy,
418 \ e -> App (Var pack_id) e)
420 -- Objects; 'dotnet' only.
421 | Just (tc, [arg_ty]) <- maybe_tc_app,
422 tyConName tc == objectTyConName
423 = dsLookupGlobalId unmarshalObjectName `thenDs` \ pack_id ->
424 returnDs (Just addrPrimTy,
425 \ e -> App (Var pack_id) e)
428 = pprPanic "resultWrapper" (ppr result_ty)
430 maybe_tc_app = splitTyConApp_maybe result_ty
432 -- When the result of a foreign call is smaller than the word size, we
433 -- need to sign- or zero-extend the result up to the word size. The C
434 -- standard appears to say that this is the responsibility of the
435 -- caller, not the callee.
437 maybeNarrow :: TyCon -> (CoreExpr -> CoreExpr)
439 | tycon `hasKey` int8TyConKey = \e -> App (Var (mkPrimOpId Narrow8IntOp)) e
440 | tycon `hasKey` int16TyConKey = \e -> App (Var (mkPrimOpId Narrow16IntOp)) e
441 | tycon `hasKey` int32TyConKey
442 && wORD_SIZE > 4 = \e -> App (Var (mkPrimOpId Narrow32IntOp)) e
444 | tycon `hasKey` word8TyConKey = \e -> App (Var (mkPrimOpId Narrow8WordOp)) e
445 | tycon `hasKey` word16TyConKey = \e -> App (Var (mkPrimOpId Narrow16WordOp)) e
446 | tycon `hasKey` word32TyConKey
447 && wORD_SIZE > 4 = \e -> App (Var (mkPrimOpId Narrow32WordOp)) e