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Diffstat (limited to 'compiler/typecheck/TcForeign.lhs')
| -rw-r--r-- | compiler/typecheck/TcForeign.lhs | 367 |
1 files changed, 367 insertions, 0 deletions
diff --git a/compiler/typecheck/TcForeign.lhs b/compiler/typecheck/TcForeign.lhs new file mode 100644 index 0000000000..4be039bd93 --- /dev/null +++ b/compiler/typecheck/TcForeign.lhs @@ -0,0 +1,367 @@ +% +% (c) The AQUA Project, Glasgow University, 1998 +% +\section[TcForeign]{Typechecking \tr{foreign} declarations} + +A foreign declaration is used to either give an externally +implemented function a Haskell type (and calling interface) or +give a Haskell function an external calling interface. Either way, +the range of argument and result types these functions can accommodate +is restricted to what the outside world understands (read C), and this +module checks to see if a foreign declaration has got a legal type. + +\begin{code} +module TcForeign + ( + tcForeignImports + , tcForeignExports + ) where + +#include "HsVersions.h" + +import HsSyn + +import TcRnMonad +import TcHsType ( tcHsSigType, UserTypeCtxt(..) ) +import TcExpr ( tcPolyExpr ) + +import ForeignCall ( CCallConv(..) ) +import ErrUtils ( Message ) +import Id ( Id, mkLocalId, mkExportedLocalId ) +#if alpha_TARGET_ARCH +import Type ( typePrimRep ) +import SMRep ( argMachRep, primRepToCgRep, primRepHint ) +#endif +import OccName ( mkForeignExportOcc ) +import Name ( Name, NamedThing(..), mkExternalName ) +import TcType ( Type, tcSplitFunTys, tcSplitTyConApp_maybe, + tcSplitForAllTys, + isFFIArgumentTy, isFFIImportResultTy, + isFFIExportResultTy, isFFILabelTy, + isFFIExternalTy, isFFIDynArgumentTy, + isFFIDynResultTy, isFFIDotnetTy, isFFIDotnetObjTy, + toDNType + ) +import ForeignCall ( CExportSpec(..), CCallTarget(..), + CLabelString, isCLabelString, + isDynamicTarget, withDNTypes, DNKind(..), DNCallSpec(..) ) +import PrelNames ( hasKey, ioTyConKey ) +import DynFlags ( DynFlags(..), HscTarget(..) ) +import Outputable +import SrcLoc ( Located(..), srcSpanStart ) +import Bag ( consBag ) + +#if alpha_TARGET_ARCH +import MachOp ( machRepByteWidth, MachHint(FloatHint) ) +#endif +\end{code} + +\begin{code} +-- Defines a binding +isForeignImport :: LForeignDecl name -> Bool +isForeignImport (L _ (ForeignImport _ _ _ _)) = True +isForeignImport _ = False + +-- Exports a binding +isForeignExport :: LForeignDecl name -> Bool +isForeignExport (L _ (ForeignExport _ _ _ _)) = True +isForeignExport _ = False +\end{code} + +%************************************************************************ +%* * +\subsection{Imports} +%* * +%************************************************************************ + +\begin{code} +tcForeignImports :: [LForeignDecl Name] -> TcM ([Id], [LForeignDecl Id]) +tcForeignImports decls + = mapAndUnzipM (wrapLocSndM tcFImport) (filter isForeignImport decls) + +tcFImport :: ForeignDecl Name -> TcM (Id, ForeignDecl Id) +tcFImport fo@(ForeignImport (L loc nm) hs_ty imp_decl isDeprec) + = addErrCtxt (foreignDeclCtxt fo) $ + tcHsSigType (ForSigCtxt nm) hs_ty `thenM` \ sig_ty -> + let + -- drop the foralls before inspecting the structure + -- of the foreign type. + (_, t_ty) = tcSplitForAllTys sig_ty + (arg_tys, res_ty) = tcSplitFunTys t_ty + id = mkLocalId nm sig_ty + -- Use a LocalId to obey the invariant that locally-defined + -- things are LocalIds. However, it does not need zonking, + -- (so TcHsSyn.zonkForeignExports ignores it). + in + tcCheckFIType sig_ty arg_tys res_ty imp_decl `thenM` \ imp_decl' -> + -- can't use sig_ty here because it :: Type and we need HsType Id + -- hence the undefined + returnM (id, ForeignImport (L loc id) undefined imp_decl' isDeprec) +\end{code} + + +------------ Checking types for foreign import ---------------------- +\begin{code} +tcCheckFIType _ arg_tys res_ty (DNImport spec) + = checkCg checkDotnet `thenM_` + getDOpts `thenM` \ dflags -> + checkForeignArgs (isFFIDotnetTy dflags) arg_tys `thenM_` + checkForeignRes True{-non IO ok-} (isFFIDotnetTy dflags) res_ty `thenM_` + let (DNCallSpec isStatic kind _ _ _ _) = spec in + (case kind of + DNMethod | not isStatic -> + case arg_tys of + [] -> addErrTc illegalDNMethodSig + _ + | not (isFFIDotnetObjTy (last arg_tys)) -> addErrTc illegalDNMethodSig + | otherwise -> returnM () + _ -> returnM ()) `thenM_` + returnM (DNImport (withDNTypes spec (map toDNType arg_tys) (toDNType res_ty))) + +tcCheckFIType sig_ty arg_tys res_ty idecl@(CImport _ _ _ _ (CLabel _)) + = checkCg checkCOrAsm `thenM_` + check (isFFILabelTy sig_ty) (illegalForeignTyErr empty sig_ty) `thenM_` + return idecl + +tcCheckFIType sig_ty arg_tys res_ty idecl@(CImport cconv _ _ _ CWrapper) + = -- Foreign wrapper (former f.e.d.) + -- The type must be of the form ft -> IO (FunPtr ft), where ft is a + -- valid foreign type. For legacy reasons ft -> IO (Ptr ft) as well + -- as ft -> IO Addr is accepted, too. The use of the latter two forms + -- is DEPRECATED, though. + checkCg checkCOrAsmOrInterp `thenM_` + checkCConv cconv `thenM_` + (case arg_tys of + [arg1_ty] -> checkForeignArgs isFFIExternalTy arg1_tys `thenM_` + checkForeignRes nonIOok isFFIExportResultTy res1_ty `thenM_` + checkForeignRes mustBeIO isFFIDynResultTy res_ty `thenM_` + checkFEDArgs arg1_tys + where + (arg1_tys, res1_ty) = tcSplitFunTys arg1_ty + other -> addErrTc (illegalForeignTyErr empty sig_ty) ) `thenM_` + return idecl + +tcCheckFIType sig_ty arg_tys res_ty idecl@(CImport cconv safety _ _ (CFunction target)) + | isDynamicTarget target -- Foreign import dynamic + = checkCg checkCOrAsmOrInterp `thenM_` + checkCConv cconv `thenM_` + case arg_tys of -- The first arg must be Ptr, FunPtr, or Addr + [] -> + check False (illegalForeignTyErr empty sig_ty) `thenM_` + return idecl + (arg1_ty:arg_tys) -> + getDOpts `thenM` \ dflags -> + check (isFFIDynArgumentTy arg1_ty) + (illegalForeignTyErr argument arg1_ty) `thenM_` + checkForeignArgs (isFFIArgumentTy dflags safety) arg_tys `thenM_` + checkForeignRes nonIOok (isFFIImportResultTy dflags) res_ty `thenM_` + return idecl + | otherwise -- Normal foreign import + = checkCg (checkCOrAsmOrDotNetOrInterp) `thenM_` + checkCConv cconv `thenM_` + checkCTarget target `thenM_` + getDOpts `thenM` \ dflags -> + checkForeignArgs (isFFIArgumentTy dflags safety) arg_tys `thenM_` + checkForeignRes nonIOok (isFFIImportResultTy dflags) res_ty `thenM_` + return idecl + +-- This makes a convenient place to check +-- that the C identifier is valid for C +checkCTarget (StaticTarget str) + = checkCg checkCOrAsmOrDotNetOrInterp `thenM_` + check (isCLabelString str) (badCName str) +\end{code} + +On an Alpha, with foreign export dynamic, due to a giant hack when +building adjustor thunks, we only allow 4 integer arguments with +foreign export dynamic (i.e., 32 bytes of arguments after padding each +argument to a quadword, excluding floating-point arguments). + +The check is needed for both via-C and native-code routes + +\begin{code} +#include "nativeGen/NCG.h" +#if alpha_TARGET_ARCH +checkFEDArgs arg_tys + = check (integral_args <= 32) err + where + integral_args = sum [ (machRepByteWidth . argMachRep . primRepToCgRep) prim_rep + | prim_rep <- map typePrimRep arg_tys, + primRepHint prim_rep /= FloatHint ] + err = ptext SLIT("On Alpha, I can only handle 32 bytes of non-floating-point arguments to foreign export dynamic") +#else +checkFEDArgs arg_tys = returnM () +#endif +\end{code} + + +%************************************************************************ +%* * +\subsection{Exports} +%* * +%************************************************************************ + +\begin{code} +tcForeignExports :: [LForeignDecl Name] + -> TcM (LHsBinds TcId, [LForeignDecl TcId]) +tcForeignExports decls + = foldlM combine (emptyLHsBinds, []) (filter isForeignExport decls) + where + combine (binds, fs) fe = + wrapLocSndM tcFExport fe `thenM` \ (b, f) -> + returnM (b `consBag` binds, f:fs) + +tcFExport :: ForeignDecl Name -> TcM (LHsBind Id, ForeignDecl Id) +tcFExport fo@(ForeignExport (L loc nm) hs_ty spec isDeprec) = + addErrCtxt (foreignDeclCtxt fo) $ + + tcHsSigType (ForSigCtxt nm) hs_ty `thenM` \ sig_ty -> + tcPolyExpr (nlHsVar nm) sig_ty `thenM` \ rhs -> + + tcCheckFEType sig_ty spec `thenM_` + + -- we're exporting a function, but at a type possibly more + -- constrained than its declared/inferred type. Hence the need + -- to create a local binding which will call the exported function + -- at a particular type (and, maybe, overloading). + + newUnique `thenM` \ uniq -> + getModule `thenM` \ mod -> + let + gnm = mkExternalName uniq mod (mkForeignExportOcc (getOccName nm)) + Nothing (srcSpanStart loc) + id = mkExportedLocalId gnm sig_ty + bind = L loc (VarBind id rhs) + in + returnM (bind, ForeignExport (L loc id) undefined spec isDeprec) +\end{code} + +------------ Checking argument types for foreign export ---------------------- + +\begin{code} +tcCheckFEType sig_ty (CExport (CExportStatic str _)) + = check (isCLabelString str) (badCName str) `thenM_` + checkForeignArgs isFFIExternalTy arg_tys `thenM_` + checkForeignRes nonIOok isFFIExportResultTy res_ty + where + -- Drop the foralls before inspecting n + -- the structure of the foreign type. + (_, t_ty) = tcSplitForAllTys sig_ty + (arg_tys, res_ty) = tcSplitFunTys t_ty +\end{code} + + + +%************************************************************************ +%* * +\subsection{Miscellaneous} +%* * +%************************************************************************ + +\begin{code} +------------ Checking argument types for foreign import ---------------------- +checkForeignArgs :: (Type -> Bool) -> [Type] -> TcM () +checkForeignArgs pred tys + = mappM go tys `thenM_` + returnM () + where + go ty = check (pred ty) (illegalForeignTyErr argument ty) + +------------ Checking result types for foreign calls ---------------------- +-- Check that the type has the form +-- (IO t) or (t) , and that t satisfies the given predicate. +-- +checkForeignRes :: Bool -> (Type -> Bool) -> Type -> TcM () + +nonIOok = True +mustBeIO = False + +checkForeignRes non_io_result_ok pred_res_ty ty + = case tcSplitTyConApp_maybe ty of + Just (io, [res_ty]) + | io `hasKey` ioTyConKey && pred_res_ty res_ty + -> returnM () + _ + -> check (non_io_result_ok && pred_res_ty ty) + (illegalForeignTyErr result ty) +\end{code} + +\begin{code} +checkDotnet HscILX = Nothing +#if defined(mingw32_TARGET_OS) +checkDotnet HscC = Nothing +checkDotnet _ = Just (text "requires C code generation (-fvia-C)") +#else +checkDotnet other = Just (text "requires .NET support (-filx or win32)") +#endif + +checkCOrAsm HscC = Nothing +checkCOrAsm HscAsm = Nothing +checkCOrAsm other + = Just (text "requires via-C or native code generation (-fvia-C)") + +checkCOrAsmOrInterp HscC = Nothing +checkCOrAsmOrInterp HscAsm = Nothing +checkCOrAsmOrInterp HscInterpreted = Nothing +checkCOrAsmOrInterp other + = Just (text "requires interpreted, C or native code generation") + +checkCOrAsmOrDotNetOrInterp HscC = Nothing +checkCOrAsmOrDotNetOrInterp HscAsm = Nothing +checkCOrAsmOrDotNetOrInterp HscILX = Nothing +checkCOrAsmOrDotNetOrInterp HscInterpreted = Nothing +checkCOrAsmOrDotNetOrInterp other + = Just (text "requires interpreted, C, native or .NET ILX code generation") + +checkCg check + = getDOpts `thenM` \ dflags -> + let target = hscTarget dflags in + case target of + HscNothing -> returnM () + otherwise -> + case check target of + Nothing -> returnM () + Just err -> addErrTc (text "Illegal foreign declaration:" <+> err) +\end{code} + +Calling conventions + +\begin{code} +checkCConv :: CCallConv -> TcM () +checkCConv CCallConv = return () +#if i386_TARGET_ARCH +checkCConv StdCallConv = return () +#else +checkCConv StdCallConv = addErrTc (text "calling convention not supported on this architecture: stdcall") +#endif +\end{code} + +Warnings + +\begin{code} +check :: Bool -> Message -> TcM () +check True _ = returnM () +check _ the_err = addErrTc the_err + +illegalForeignTyErr arg_or_res ty + = hang (hsep [ptext SLIT("Unacceptable"), arg_or_res, + ptext SLIT("type in foreign declaration:")]) + 4 (hsep [ppr ty]) + +-- Used for 'arg_or_res' argument to illegalForeignTyErr +argument = text "argument" +result = text "result" + +badCName :: CLabelString -> Message +badCName target + = sep [quotes (ppr target) <+> ptext SLIT("is not a valid C identifier")] + +foreignDeclCtxt fo + = hang (ptext SLIT("When checking declaration:")) + 4 (ppr fo) + +illegalDNMethodSig + = ptext SLIT("'This pointer' expected as last argument") + +\end{code} + |