import CoreUtils ( coreExprType )
import Const ( Con(..), mkMachInt )
import DataCon ( DataCon, dataConId )
-import Id ( Id, idType, idName,
- mkIdVisible, mkWildId
- )
+import Id ( Id, idType, idName, mkWildId, mkVanillaId )
import Const ( Literal(..) )
-import Name ( getOccString, NamedThing(..) )
-import PrelVals ( realWorldPrimId )
-import PrelInfo ( deRefStablePtr_NAME, bindIO_NAME, makeStablePtr_NAME )
+import Module ( Module )
+import Name ( mkGlobalName, nameModule, nameOccName, getOccString,
+ mkForeignExportOcc, isLocalName,
+ NamedThing(..), Provenance(..), ExportFlag(..)
+ )
+import PrelInfo ( deRefStablePtr_NAME, bindIO_NAME, makeStablePtr_NAME, realWorldPrimId )
import Type ( splitAlgTyConApp_maybe,
splitTyConApp_maybe, splitFunTys, splitForAllTys,
Type, mkFunTys, mkForAllTys, mkTyConApp,
Desugaring of @foreign@ declarations is naturally split up into
parts, an @import@ and an @export@ part. A @foreign import@
-declaration
-
+declaration
+\begin{verbatim}
foreign import cc nm f :: prim_args -> IO prim_res
-
+\end{verbatim}
is the same as
-
+\begin{verbatim}
f :: prim_args -> IO prim_res
f a1 ... an = _ccall_ nm cc a1 ... an
-
+\end{verbatim}
so we reuse the desugaring code in @DsCCall@ to deal with these.
\begin{code}
-dsForeigns :: [TypecheckedForeignDecl]
+dsForeigns :: Module
+ -> [TypecheckedForeignDecl]
-> DsM ( [CoreBind] -- desugared foreign imports
, [CoreBind] -- helper functions for foreign exports
- , SDoc -- Header file prototypes for "foreign exported" functions.
- , SDoc -- C stubs to use when calling "foreign exported" funs.
+ , SDoc -- Header file prototypes for
+ -- "foreign exported" functions.
+ , SDoc -- C stubs to use when calling
+ -- "foreign exported" functions.
)
-dsForeigns fos = foldlDs combine ([],[],empty,empty) fos
+dsForeigns mod_name fos = foldlDs combine ([],[],empty,empty) fos
where
combine (acc_fi, acc_fe, acc_h, acc_c) fo@(ForeignDecl i imp_exp _ ext_nm cconv _)
| isForeignImport = -- foreign import (dynamic)?
dsFLabel i ext_nm `thenDs` \ b ->
returnDs (b:acc_fi, acc_fe, acc_h, acc_c)
| isDynamic ext_nm =
- dsFExportDynamic i (idType i) ext_nm cconv `thenDs` \ (fi,fe,h,c) ->
+ dsFExportDynamic i (idType i) mod_name ext_nm cconv `thenDs` \ (fi,fe,h,c) ->
returnDs (fi:acc_fi, fe:acc_fe, h $$ acc_h, c $$ acc_c)
| otherwise = -- foreign export
- dsFExport i (idType i) ext_nm cconv False `thenDs` \ (fe,h,c) ->
+ dsFExport i (idType i) mod_name ext_nm cconv False `thenDs` \ (fe,h,c) ->
returnDs (acc_fi, fe:acc_fe, h $$ acc_h, c $$ acc_c)
where
isForeignImport =
Desugaring foreign imports is just the matter of creating a binding
that on its RHS unboxes its arguments, performs the external call
-(using the CCallOp primop), before boxing the result up and returning it.
+(using the @CCallOp@ primop), before boxing the result up and returning it.
\begin{code}
dsFImport :: Id
[Type io_res_ty, Var ds]
fo_rhs = mkLams (tvs ++ args)
- (Let (NonRec ds (the_body::CoreExpr)) io_app)
+ (mkDsLet (NonRec ds (the_body::CoreExpr)) io_app)
in
returnDs (NonRec nm fo_rhs)
\end{code}
\end{code}
-The function that does most of the work for 'foreign export' declarations.
-(see below for the boilerplate code a 'foreign export' declaration expands
+The function that does most of the work for `@foreign export@' declarations.
+(see below for the boilerplate code a `@foreign export@' declaration expands
into.)
+For each `@foreign export foo@' in a module M we generate:
+\begin{itemize}
+\item a C function `@foo@', which calls
+\item a Haskell stub `@M.$ffoo@', which calls
+\end{itemize}
+the user-written Haskell function `@M.foo@'.
+
\begin{code}
dsFExport :: Id
-> Type -- Type of foreign export.
+ -> Module
-> ExtName
-> CallConv
-> Bool -- True => invoke IO action that's hanging off
, SDoc
, SDoc
)
-dsFExport i ty ext_name cconv isDyn =
- newSysLocalDs helper_ty `thenDs` \ f_helper ->
+dsFExport i ty mod_name ext_name cconv isDyn =
+ getUniqueDs `thenDs` \ uniq ->
+ getSrcLocDs `thenDs` \ src_loc ->
+ let
+ f_helper_glob = mkVanillaId helper_name helper_ty
+ where
+ name = idName i
+ mod
+ | isLocalName name = mod_name
+ | otherwise = nameModule name
+
+ occ = mkForeignExportOcc (nameOccName name)
+ prov = LocalDef src_loc Exported
+ helper_name = mkGlobalName uniq mod occ prov
+ in
newSysLocalsDs fe_arg_tys `thenDs` \ fe_args ->
(if isDyn then
newSysLocalDs stbl_ptr_ty `thenDs` \ stbl_ptr ->
returnDs (i,
\ body -> body,
panic "stbl_ptr" -- should never be touched.
- )) `thenDs` \ (i, getFun_wrapper, stbl_ptr) ->
+ )) `thenDs` \ (i, getFun_wrapper, stbl_ptr) ->
let
wrapper_args
| isDyn = stbl_ptr:fe_args
ExtName fs _ -> fs
Dynamic -> panic "dsFExport: Dynamic - shouldn't ever happen."
- f_helper_glob = mkIdVisible mod uniq f_helper
- (h_stub, c_stub) = fexportEntry c_nm f_helper_glob wrapper_arg_tys the_result_ty cconv
+ (h_stub, c_stub) = fexportEntry c_nm f_helper_glob
+ wrapper_arg_tys the_result_ty cconv isDyn
in
returnDs (NonRec f_helper_glob the_body, h_stub, c_stub)
\end{code}
-"foreign export dynamic" lets you dress up Haskell IO actions
+@foreign export dynamic@ lets you dress up Haskell IO actions
of some fixed type behind an externally callable interface (i.e.,
as a C function pointer). Useful for callbacks and stuff.
\begin{code}
dsFExportDynamic :: Id
-> Type -- Type of foreign export.
+ -> Module
-> ExtName
-> CallConv
-> DsM (CoreBind, CoreBind, SDoc, SDoc)
-dsFExportDynamic i ty ext_name cconv =
+dsFExportDynamic i ty mod_name ext_name cconv =
newSysLocalDs ty `thenDs` \ fe_id ->
let
-- hack: need to get at the name of the C stub we're about to generate.
fe_nm = toCName fe_id
fe_ext_name = ExtName (_PK_ fe_nm) Nothing
in
- dsFExport i export_ty fe_ext_name cconv True `thenDs` \ (fe@(NonRec fe_helper fe_expr), h_code, c_code) ->
- newSysLocalDs arg_ty `thenDs` \ cback ->
+ dsFExport i export_ty mod_name fe_ext_name cconv True
+ `thenDs` \ (fe@(NonRec fe_helper fe_expr), h_code, c_code) ->
+ newSysLocalDs arg_ty `thenDs` \ cback ->
dsLookupGlobalValue makeStablePtr_NAME `thenDs` \ makeStablePtrId ->
let
mk_stbl_ptr_app = mkApps (Var makeStablePtrId) [ Type arg_ty, Var cback ]
using the hugs/ghc rts invocation API.
\begin{code}
-fexportEntry :: FAST_STRING -> Id -> [Type] -> Maybe Type -> CallConv -> (SDoc, SDoc)
-fexportEntry c_nm helper args res cc = (header_bits, c_bits)
+fexportEntry :: FAST_STRING
+ -> Id
+ -> [Type]
+ -> Maybe Type
+ -> CallConv
+ -> Bool
+ -> (SDoc, SDoc)
+fexportEntry c_nm helper args res cc isDyn = (header_bits, c_bits)
where
-- name of the (Haskell) helper function generated by the desugarer.
h_nm = ppr helper <> text "_closure"
header_bits = ptext SLIT("extern") <+> fun_proto <> semi
fun_proto = cResType <+> pprCconv <+> ptext c_nm <>
- parens (hsep (punctuate comma (zipWith (<+>) cParamTypes c_args)))
+ parens (hsep (punctuate comma (zipWith (<+>) cParamTypes proto_args)))
c_bits =
externDecl $$
appArg acc (a,c_a) =
text "rts_apply" <> parens (acc <> comma <> mkHObj a <> parens c_a)
- cParamTypes = map showStgType args
+ cParamTypes = map showStgType real_args
cResType =
case res of
Nothing -> empty
Just t -> unpackHObj t <> parens (text "ret")
- c_args = zipWith (\ _ n -> text ('a':show n)) args [0..]
+ c_args = mkCArgNames 0 args
+
+ {-
+ If we're generating an entry point for a 'foreign export ccall dynamic',
+ then we receive the return address of the C function that wants to
+ invoke a Haskell function as any other C function, as second arg.
+ This arg is unused within the body of the generated C stub, but
+ needed by the Adjustor.c code to get the stack cleanup right.
+ -}
+ (proto_args, real_args)
+ | cc == cCallConv && isDyn = ( text "a0" : text "a_" : mkCArgNames 1 (tail args)
+ , head args : addrTy : tail args)
+ | otherwise = (mkCArgNames 0 args, args)
+
+mkCArgNames :: Int -> [a] -> [SDoc]
+mkCArgNames n as = zipWith (\ _ n -> text ('a':show n)) as [n..]
mkHObj :: Type -> SDoc
-mkHObj t = text "rts_mk" <> showFFIType t
+mkHObj t = text "rts_mk" <> text (showFFIType t)
unpackHObj :: Type -> SDoc
-unpackHObj t = text "rts_get" <> showFFIType t
+unpackHObj t = text "rts_get" <> text (showFFIType t)
showStgType :: Type -> SDoc
-showStgType t = text "Stg" <> showFFIType t
+showStgType t = text "Stg" <> text (showFFIType t)
-showFFIType :: Type -> SDoc
-showFFIType t = text (getOccString (getName tc))
+showFFIType :: Type -> String
+showFFIType t = getOccString (getName tc)
where
tc = case splitTyConApp_maybe t of
Just (tc,_) -> tc
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