import CoreSyn
-import DsCCall ( dsCCall, boxResult, unboxArg, wrapUnboxedValue )
+import DsCCall ( dsCCall, mkCCall, boxResult, unboxArg )
import DsMonad
import DsUtils
-import HsSyn ( ExtName(..), ForeignDecl(..), isDynamic, ForKind(..) )
+import HsSyn ( ExtName(..), ForeignDecl(..), isDynamicExtName, ForKind(..) )
+import HsDecls ( extNameStatic )
import CallConv
import TcHsSyn ( TypecheckedForeignDecl )
-import CoreUtils ( coreExprType )
-import Const ( Con(..), mkMachInt )
-import DataCon ( DataCon, dataConId )
-import Id ( Id, idType, idName,
- mkIdVisible, mkWildId
+import CoreUtils ( exprType, mkInlineMe, bindNonRec )
+import DataCon ( DataCon, dataConWrapId )
+import Id ( Id, idType, idName, mkWildId, mkVanillaId )
+import MkId ( mkWorkerId )
+import Literal ( Literal(..) )
+import Module ( Module, moduleUserString )
+import Name ( mkGlobalName, nameModule, nameOccName, getOccString,
+ mkForeignExportOcc, isLocalName,
+ NamedThing(..), Provenance(..), ExportFlag(..)
)
-import Const ( Literal(..) )
-import Name ( getOccString, NamedThing(..) )
-import PrelVals ( realWorldPrimId )
import PrelInfo ( deRefStablePtr_NAME, bindIO_NAME, makeStablePtr_NAME )
-import Type ( splitAlgTyConApp_maybe,
+import Type ( unUsgTy,
splitTyConApp_maybe, splitFunTys, splitForAllTys,
Type, mkFunTys, mkForAllTys, mkTyConApp,
mkTyVarTy, mkFunTy, splitAppTy
)
-import PrimOp ( PrimOp(..) )
+import PrimOp ( PrimOp(..), CCall(..), CCallTarget(..) )
import Var ( TyVar )
import TysPrim ( realWorldStatePrimTy, addrPrimTy )
import TysWiredIn ( unitTyCon, addrTy, stablePtrTyCon,
unboxedTupleCon, addrDataCon
)
import Unique
+import Maybes ( maybeToBool )
import Outputable
\end{code}
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)?
- dsFImport i (idType i) uns ext_nm cconv `thenDs` \ b ->
- returnDs (b:acc_fi, acc_fe, acc_h, acc_c)
+ dsFImport i (idType i) uns ext_nm cconv `thenDs` \ bs ->
+ returnDs (bs ++ acc_fi, acc_fe, acc_h, acc_c)
| isForeignLabel =
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) ->
+ | isDynamicExtName ext_nm =
+ 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.
+
+However, we create a worker/wrapper pair, thus:
+
+ foreign import f :: Int -> IO Int
+==>
+ f x = IO ( \s -> case x of { I# x# ->
+ case fw s x# of { (# s1, y# #) ->
+ (# s1, I# y# #)}})
+
+ fw s x# = ccall f s x#
+
+The strictness/CPR analyser won't do this automatically because it doesn't look
+inside returned tuples; but inlining this wrapper is a Really Good Idea
+because it exposes the boxing to the call site.
+
\begin{code}
dsFImport :: Id
-> Bool -- True <=> might cause Haskell GC
-> ExtName
-> CallConv
- -> DsM CoreBind
-dsFImport nm ty may_not_gc ext_name cconv =
- newSysLocalDs realWorldStatePrimTy `thenDs` \ old_s ->
- splitForeignTyDs ty `thenDs` \ (tvs, args, mbIoDataCon, io_res_ty) ->
- let
- the_state_arg
- | is_io_action = old_s
- | otherwise = realWorldPrimId
-
- arg_exprs = map (Var) args
-
- is_io_action =
- case mbIoDataCon of
- Nothing -> False
- _ -> True
+ -> DsM [CoreBind]
+dsFImport fn_id ty may_not_gc ext_name cconv
+ = let
+ (tvs, fun_ty) = splitForAllTys ty
+ (arg_tys, io_res_ty) = splitFunTys fun_ty
in
- mapAndUnzipDs unboxArg arg_exprs `thenDs` \ (unboxed_args, arg_wrappers) ->
- (if not is_io_action then
- newSysLocalDs realWorldStatePrimTy `thenDs` \ state_tok ->
- wrapUnboxedValue io_res_ty `thenDs` \ (ccall_result_ty, v, res_v) ->
- returnDs ( ccall_result_ty
- , \ prim_app -> Case prim_app (mkWildId ccall_result_ty)
- [(DataCon (unboxedTupleCon 2), [state_tok, v], res_v)])
- else
- boxResult io_res_ty) `thenDs` \ (final_result_ty, res_wrapper) ->
+ newSysLocalsDs arg_tys `thenDs` \ args ->
+ mapAndUnzipDs unboxArg (map Var args) `thenDs` \ (val_args, arg_wrappers) ->
+ boxResult io_res_ty `thenDs` \ (ccall_result_ty, res_wrapper) ->
+
(case ext_name of
Dynamic -> getUniqueDs `thenDs` \ u ->
- returnDs (Right u)
- ExtName fs _ -> returnDs (Left fs)) `thenDs` \ label ->
- let
- val_args = Var the_state_arg : unboxed_args
- final_args = Type inst_ty : val_args
-
- -- A CCallOp has type (forall a. a), so we must instantiate
- -- it at the full type, including the state argument
- inst_ty = mkFunTys (map coreExprType val_args) final_result_ty
-
- the_ccall_op = CCallOp label False (not may_not_gc) cconv
-
- the_prim_app = mkPrimApp the_ccall_op (final_args :: [CoreArg])
-
- body = foldr ($) (res_wrapper the_prim_app) arg_wrappers
+ returnDs (DynamicTarget u)
+ ExtName fs _ -> returnDs (StaticTarget fs)) `thenDs` \ lbl ->
- the_body
- | not is_io_action = body
- | otherwise = Lam old_s body
- in
- newSysLocalDs (coreExprType the_body) `thenDs` \ ds ->
+ getUniqueDs `thenDs` \ ccall_uniq ->
+ getUniqueDs `thenDs` \ work_uniq ->
let
- io_app =
- case mbIoDataCon of
- Nothing -> Var ds
- Just ioDataCon ->
- mkApps (Var (dataConId ioDataCon))
- [Type io_res_ty, Var ds]
-
- fo_rhs = mkLams (tvs ++ args)
- (Let (NonRec ds (the_body::CoreExpr)) io_app)
+ -- Build the worker
+ work_arg_ids = [v | Var v <- val_args] -- All guaranteed to be vars
+ worker_ty = mkForAllTys tvs (mkFunTys (map idType work_arg_ids) ccall_result_ty)
+ the_ccall = CCall lbl False (not may_not_gc) cconv
+ the_ccall_app = mkCCall ccall_uniq the_ccall val_args ccall_result_ty
+ work_rhs = mkLams tvs (mkLams work_arg_ids the_ccall_app)
+ work_id = mkWorkerId work_uniq fn_id worker_ty
+
+ -- Build the wrapper
+ work_app = mkApps (mkVarApps (Var work_id) tvs) val_args
+ wrapper_body = foldr ($) (res_wrapper work_app) arg_wrappers
+ wrap_rhs = mkInlineMe (mkLams (tvs ++ args) wrapper_body)
in
- returnDs (NonRec nm fo_rhs)
+ returnDs [NonRec fn_id wrap_rhs, NonRec work_id work_rhs]
\end{code}
-Given the type of a foreign import declaration, split it up into
-its constituent parts.
-
-\begin{code}
-splitForeignTyDs :: Type -> DsM ([TyVar], [Id], Maybe DataCon, Type)
-splitForeignTyDs ty =
- newSysLocalsDs arg_tys `thenDs` \ ds_args ->
- case splitAlgTyConApp_maybe res_ty of
- Just (_,(io_res_ty:_),(ioCon:_)) -> -- .... -> IO t
- returnDs (tvs, ds_args, Just ioCon, io_res_ty)
- _ -> -- .... -> t
- returnDs (tvs, ds_args, Nothing, res_ty)
- where
- (arg_tys, res_ty) = splitFunTys sans_foralls
- (tvs, sans_foralls) = splitForAllTys ty
-
-\end{code}
-
-foreign labels
+Foreign labels
\begin{code}
dsFLabel :: Id -> ExtName -> DsM CoreBind
dsFLabel nm ext_name = returnDs (NonRec nm fo_rhs)
where
fo_rhs = mkConApp addrDataCon [mkLit (MachLitLit enm addrPrimTy)]
- enm =
- case ext_name of
- ExtName f _ -> f
- Dynamic -> panic "dsFLabel: Dynamic - shouldn't ever happen."
-
+ enm = extNameStatic ext_name
\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 ->
the_deref_app = mkApps (Var deRefStablePtrId)
[ Type stbl_ptr_to_ty, Var stbl_ptr ]
in
- newSysLocalDs (coreExprType the_deref_app) `thenDs` \ x_deref_app ->
+ newSysLocalDs (exprType the_deref_app) `thenDs` \ x_deref_app ->
dsLookupGlobalValue bindIO_NAME `thenDs` \ bindIOId ->
newSysLocalDs (mkFunTy stbl_ptr_to_ty
(mkTyConApp ioTyCon [res_ty])) `thenDs` \ x_cont ->
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
getFun_wrapper $
mkApps (Var i) (map (Type . mkTyVarTy) tvs ++ map Var fe_args)
in
- getModuleAndGroupDs `thenDs` \ (mod,_) ->
+ getModuleDs `thenDs` \ mod ->
getUniqueDs `thenDs` \ uniq ->
let
the_body = mkLams (tvs ++ wrapper_args) the_app
+ c_nm = extNameStatic ext_name
- c_nm =
- case ext_name of
- 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 isDyn
+ (h_stub, c_stub) = fexportEntry (moduleUserString mod)
+ 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 ]
- mk_stbl_ptr_app_ty = coreExprType mk_stbl_ptr_app
+ mk_stbl_ptr_app_ty = exprType mk_stbl_ptr_app
in
newSysLocalDs mk_stbl_ptr_app_ty `thenDs` \ x_mk_stbl_ptr_app ->
dsLookupGlobalValue bindIO_NAME `thenDs` \ bindIOId ->
to be entered using an external calling convention
(stdcall, ccall).
-}
- adj_args = [ mkLit (mkMachInt (fromInt (callConvToInt cconv)))
+ adj_args = [ mkIntLitInt (callConvToInt cconv)
, Var stbl_value
, mkLit (MachLitLit (_PK_ fe_nm) addrPrimTy)
]
adjustor = SLIT("createAdjustor")
in
dsCCall adjustor adj_args False False addrTy `thenDs` \ ccall_adj ->
- let ccall_adj_ty = coreExprType ccall_adj
+ let ccall_adj_ty = exprType ccall_adj
in
newSysLocalDs ccall_adj_ty `thenDs` \ x_ccall_adj ->
let ccall_io_adj =
mkLams [stbl_value] $
bindNonRec x_ccall_adj ccall_adj $
- Note (Coerce (mkTyConApp ioTyCon [res_ty]) ccall_adj_ty)
+ Note (Coerce (mkTyConApp ioTyCon [res_ty]) (unUsgTy ccall_adj_ty))
(Var x_ccall_adj)
in
- newSysLocalDs (coreExprType ccall_io_adj) `thenDs` \ x_ccall_io_adj ->
+ newSysLocalDs (exprType ccall_io_adj) `thenDs` \ x_ccall_io_adj ->
let io_app = mkLams tvs $
mkLams [cback] $
stbl_app x_ccall_io_adj ccall_io_adj addrTy
using the hugs/ghc rts invocation API.
\begin{code}
-fexportEntry :: FAST_STRING
+fexportEntry :: String
+ -> FAST_STRING
-> Id
-> [Type]
-> Maybe Type
-> CallConv
-> Bool
-> (SDoc, SDoc)
-fexportEntry c_nm helper args res cc isDyn = (header_bits, c_bits)
+fexportEntry mod_nm 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"
returnResult =
text "rts_checkSchedStatus" <>
- parens (doubleQuotes (ptext c_nm) <> comma <> text "rc") <> semi $$
+ parens (doubleQuotes (text mod_nm <> char '.' <> ptext c_nm) <> comma <> text "rc") <> semi $$
(case res of
Nothing -> text "return"
Just _ -> text "return" <> parens (res_name)) <> semi
, head args : addrTy : tail args)
| otherwise = (mkCArgNames 0 args, args)
- mkCArgNames n as = zipWith (\ _ n -> text ('a':show n)) as [n..]
+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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