2 % (c) The AQUA Project, Glasgow University, 1998
4 \section[TcForeign]{Typechecking \tr{foreign} declarations}
6 A foreign declaration is used to either give an externally
7 implemented function a Haskell type (and calling interface) or
8 give a Haskell function an external calling interface. Either way,
9 the range of argument and result types these functions can accommodate
10 is restricted to what the outside world understands (read C), and this
11 module checks to see if a foreign declaration has got a legal type.
20 #include "HsVersions.h"
22 import HsSyn ( HsDecl(..), ForeignDecl(..), HsExpr(..),
23 MonoBinds(..), ForeignImport(..), ForeignExport(..),
26 import RnHsSyn ( RenamedHsDecl, RenamedForeignDecl )
29 import TcEnv ( newLocalName )
30 import TcMonoType ( tcHsSigType, UserTypeCtxt(..) )
31 import TcHsSyn ( TcMonoBinds, TypecheckedForeignDecl, TcForeignExportDecl )
32 import TcExpr ( tcExpr )
33 import Inst ( emptyLIE, LIE, plusLIE )
35 import ErrUtils ( Message )
36 import Id ( Id, mkLocalId )
37 import PrimRep ( getPrimRepSize, isFloatingRep )
38 import Type ( typePrimRep )
39 import TcType ( Type, tcSplitFunTys, tcSplitTyConApp_maybe,
41 isFFIArgumentTy, isFFIImportResultTy,
42 isFFIExportResultTy, isFFILabelTy,
43 isFFIExternalTy, isFFIDynArgumentTy,
44 isFFIDynResultTy, isForeignPtrTy
46 import ForeignCall ( CCallSpec(..), CExportSpec(..), CCallTarget(..),
47 isDynamicTarget, isCasmTarget )
48 import CStrings ( CLabelString, isCLabelString )
49 import PrelNames ( hasKey, ioTyConKey )
50 import CmdLineOpts ( dopt_HscLang, HscLang(..) )
57 isForeignImport :: ForeignDecl name -> Bool
58 isForeignImport (ForeignImport _ _ _ _ _) = True
59 isForeignImport _ = False
62 isForeignExport :: ForeignDecl name -> Bool
63 isForeignExport (ForeignExport _ _ _ _ _) = True
64 isForeignExport _ = False
67 %************************************************************************
71 %************************************************************************
74 tcForeignImports :: [RenamedHsDecl] -> TcM ([Id], [TypecheckedForeignDecl])
75 tcForeignImports decls =
76 mapAndUnzipTc tcFImport
77 [ foreign_decl | ForD foreign_decl <- decls, isForeignImport foreign_decl]
79 tcFImport :: RenamedForeignDecl -> TcM (Id, TypecheckedForeignDecl)
80 tcFImport fo@(ForeignImport nm hs_ty imp_decl isDeprec src_loc)
81 = tcAddSrcLoc src_loc $
82 tcAddErrCtxt (foreignDeclCtxt fo) $
83 tcHsSigType (ForSigCtxt nm) hs_ty `thenTc` \ sig_ty ->
85 -- drop the foralls before inspecting the structure
86 -- of the foreign type.
87 (_, t_ty) = tcSplitForAllTys sig_ty
88 (arg_tys, res_ty) = tcSplitFunTys t_ty
89 id = mkLocalId nm sig_ty
91 tcCheckFIType sig_ty arg_tys res_ty imp_decl `thenNF_Tc_`
92 returnTc (id, ForeignImport id undefined imp_decl isDeprec src_loc)
96 ------------ Checking types for foreign import ----------------------
98 tcCheckFIType _ _ _ (DNImport _)
101 tcCheckFIType sig_ty arg_tys res_ty (CImport _ _ _ _ (CLabel _))
102 = checkCg checkCOrAsm `thenNF_Tc_`
103 check (isFFILabelTy sig_ty) (illegalForeignTyErr empty sig_ty)
105 tcCheckFIType sig_ty arg_tys res_ty (CImport _ _ _ _ CWrapper)
106 = -- Foreign wrapper (former f.e.d.)
107 -- The type must be of the form ft -> IO (FunPtr ft), where ft is a
108 -- valid foreign type. For legacy reasons ft -> IO (Ptr ft) as well
109 -- as ft -> IO Addr is accepted, too. The use of the latter two forms
110 -- is DEPRECATED, though.
111 checkCg checkCOrAsm `thenNF_Tc_`
113 [arg1_ty] -> checkForeignArgs isFFIExternalTy arg1_tys `thenNF_Tc_`
114 checkForeignRes nonIOok isFFIExportResultTy res1_ty `thenNF_Tc_`
115 checkForeignRes mustBeIO isFFIDynResultTy res_ty `thenNF_Tc_`
116 checkFEDArgs arg1_tys
118 (arg1_tys, res1_ty) = tcSplitFunTys arg1_ty
119 other -> addErrTc (illegalForeignTyErr empty sig_ty)
121 tcCheckFIType sig_ty arg_tys res_ty (CImport _ safety _ _ (CFunction target))
122 | isDynamicTarget target -- Foreign import dynamic
123 = checkCg checkCOrAsmOrInterp `thenNF_Tc_`
124 case arg_tys of -- The first arg must be Ptr, FunPtr, or Addr
125 [] -> check False (illegalForeignTyErr empty sig_ty)
126 (arg1_ty:arg_tys) -> getDOptsTc `thenNF_Tc` \ dflags ->
127 check (isFFIDynArgumentTy arg1_ty)
128 (illegalForeignTyErr argument arg1_ty) `thenNF_Tc_`
129 checkForeignArgs (isFFIArgumentTy dflags safety) arg_tys `thenNF_Tc_`
130 checkForeignRes nonIOok (isFFIImportResultTy dflags) res_ty
132 | otherwise -- Normal foreign import
133 = checkCg (if isCasmTarget target
134 then checkC else checkCOrAsmOrDotNetOrInterp) `thenNF_Tc_`
135 checkCTarget target `thenNF_Tc_`
136 getDOptsTc `thenNF_Tc` \ dflags ->
137 checkForeignArgs (isFFIArgumentTy dflags safety) arg_tys `thenNF_Tc_`
138 checkForeignRes nonIOok (isFFIImportResultTy dflags) res_ty
140 -- This makes a convenient place to check
141 -- that the C identifier is valid for C
142 checkCTarget (StaticTarget str)
143 = checkCg checkCOrAsmOrDotNetOrInterp `thenNF_Tc_`
144 check (isCLabelString str) (badCName str)
146 checkCTarget (CasmTarget _)
150 On a SPARC, with foreign export dynamic, due to a giant hack when building
151 adjustor thunks, we only allow 16 bytes of arguments!
153 So for example, args (Int,Double,Int) would be OK (1+2+1)
154 as would (Int,Int,Int,Int) (1+1+1+1) but not (Int,Double,Double) (1+2+2).
156 On an Alpha, due to a similar hack, we only allow 4 integer arguments with
157 foreign export dynamic (i.e., 32 bytes of arguments after padding each
158 argument to a quadword, excluding floating-point arguments).
160 The check is needed for both via-C and native-code routes
163 #include "nativeGen/NCG.h"
164 #if sparc_TARGET_ARCH
166 = check (words_of_args <= 4) err
168 words_of_args = sum (map (getPrimRepSize . typePrimRep) arg_tys)
169 err = ptext SLIT("On SPARC, I can only handle 4 words of arguments to foreign export dynamic")
171 #if alpha_TARGET_ARCH
173 = check (integral_args <= 4) err
175 integral_args = sum (map getPrimRepSize $
176 filter (not . isFloatingRep) $
177 map typePrimRep arg_tys)
178 err = ptext SLIT("On Alpha, I can only handle 4 non-floating-point arguments to foreign export dynamic")
180 checkFEDArgs arg_tys = returnNF_Tc ()
186 %************************************************************************
190 %************************************************************************
193 tcForeignExports :: [RenamedHsDecl] -> TcM (LIE, TcMonoBinds, [TcForeignExportDecl])
194 tcForeignExports decls =
195 foldlTc combine (emptyLIE, EmptyMonoBinds, [])
196 [foreign_decl | ForD foreign_decl <- decls, isForeignExport foreign_decl]
198 combine (lie, binds, fs) fe =
199 tcFExport fe `thenTc ` \ (a_lie, b, f) ->
200 returnTc (lie `plusLIE` a_lie, b `AndMonoBinds` binds, f:fs)
202 tcFExport :: RenamedForeignDecl -> TcM (LIE, TcMonoBinds, TcForeignExportDecl)
203 tcFExport fo@(ForeignExport nm hs_ty spec isDeprec src_loc) =
204 tcAddSrcLoc src_loc $
205 tcAddErrCtxt (foreignDeclCtxt fo) $
207 tcHsSigType (ForSigCtxt nm) hs_ty `thenTc` \ sig_ty ->
208 tcExpr (HsVar nm) sig_ty `thenTc` \ (rhs, lie) ->
210 tcCheckFEType sig_ty spec `thenTc_`
212 -- we're exporting a function, but at a type possibly more
213 -- constrained than its declared/inferred type. Hence the need
214 -- to create a local binding which will call the exported function
215 -- at a particular type (and, maybe, overloading).
216 newLocalName nm `thenNF_Tc` \ id_name ->
218 id = mkLocalId id_name sig_ty
219 bind = VarMonoBind id rhs
221 returnTc (lie, bind, ForeignExport id undefined spec isDeprec src_loc)
224 ------------ Checking argument types for foreign export ----------------------
227 tcCheckFEType sig_ty (CExport (CExportStatic str _))
228 = check (isCLabelString str) (badCName str) `thenNF_Tc_`
229 checkForeignArgs isFFIExternalTy arg_tys `thenNF_Tc_`
230 checkForeignRes nonIOok isFFIExportResultTy res_ty
232 -- Drop the foralls before inspecting n
233 -- the structure of the foreign type.
234 (_, t_ty) = tcSplitForAllTys sig_ty
235 (arg_tys, res_ty) = tcSplitFunTys t_ty
240 %************************************************************************
242 \subsection{Miscellaneous}
244 %************************************************************************
247 ------------ Checking argument types for foreign import ----------------------
248 checkForeignArgs :: (Type -> Bool) -> [Type] -> NF_TcM ()
249 checkForeignArgs pred tys
250 = mapNF_Tc go tys `thenNF_Tc_`
253 go ty = check (pred ty) (illegalForeignTyErr argument ty) `thenNF_Tc_`
254 warnTc (isForeignPtrTy ty) foreignPtrWarn
257 text "`ForeignPtr' as argument type in a foreign import is deprecated"
259 ------------ Checking result types for foreign calls ----------------------
260 -- Check that the type has the form
261 -- (IO t) or (t) , and that t satisfies the given predicate.
263 checkForeignRes :: Bool -> (Type -> Bool) -> Type -> NF_TcM ()
268 checkForeignRes non_io_result_ok pred_res_ty ty
269 = case tcSplitTyConApp_maybe ty of
271 | io `hasKey` ioTyConKey && pred_res_ty res_ty
274 -> check (non_io_result_ok && pred_res_ty ty)
275 (illegalForeignTyErr result ty)
279 checkDotNet HscILX = Nothing
280 checkDotNet other = Just (text "requires .NET code generation (-filx)")
282 checkC HscC = Nothing
283 checkC other = Just (text "requires C code generation (-fvia-C)")
285 checkCOrAsm HscC = Nothing
286 checkCOrAsm HscAsm = Nothing
288 = Just (text "requires via-C or native code generation (-fvia-C)")
290 checkCOrAsmOrInterp HscC = Nothing
291 checkCOrAsmOrInterp HscAsm = Nothing
292 checkCOrAsmOrInterp HscInterpreted = Nothing
293 checkCOrAsmOrInterp other
294 = Just (text "requires interpreted, C or native code generation")
296 checkCOrAsmOrDotNet HscC = Nothing
297 checkCOrAsmOrDotNet HscAsm = Nothing
298 checkCOrAsmOrDotNet HscILX = Nothing
299 checkCOrAsmOrDotNet other
300 = Just (text "requires C, native or .NET ILX code generation")
302 checkCOrAsmOrDotNetOrInterp HscC = Nothing
303 checkCOrAsmOrDotNetOrInterp HscAsm = Nothing
304 checkCOrAsmOrDotNetOrInterp HscILX = Nothing
305 checkCOrAsmOrDotNetOrInterp HscInterpreted = Nothing
306 checkCOrAsmOrDotNetOrInterp other
307 = Just (text "requires interpreted, C, native or .NET ILX code generation")
310 = getDOptsTc `thenNF_Tc` \ dflags ->
311 let hscLang = dopt_HscLang dflags in
313 HscNothing -> returnNF_Tc ()
315 case check hscLang of
316 Nothing -> returnNF_Tc ()
317 Just err -> addErrTc (text "Illegal foreign declaration:" <+> err)
323 check :: Bool -> Message -> NF_TcM ()
324 check True _ = returnTc ()
325 check _ the_err = addErrTc the_err
327 illegalForeignTyErr arg_or_res ty
328 = hang (hsep [ptext SLIT("Unacceptable"), arg_or_res,
329 ptext SLIT("type in foreign declaration:")])
332 -- Used for 'arg_or_res' argument to illegalForeignTyErr
333 argument = text "argument"
334 result = text "result"
336 badCName :: CLabelString -> Message
338 = sep [quotes (ppr target) <+> ptext SLIT("is not a valid C identifier")]
341 = hang (ptext SLIT("When checking declaration:"))