import CoreSyn
-import DsCCall ( dsCCall, boxResult, unboxArg, wrapUnboxedValue )
+import DsCCall ( dsCCall, mkFCall, boxResult, unboxArg, resultWrapper )
import DsMonad
-import DsUtils
-import HsSyn ( ExtName(..), ForeignDecl(..), isDynamic, ForKind(..) )
-import CallConv
+import HsSyn ( ForeignDecl(..), ForeignExport(..),
+ ForeignImport(..), CImportSpec(..) )
import TcHsSyn ( TypecheckedForeignDecl )
-import CoreUtils ( coreExprType )
-import Const ( Con(..), mkMachInt )
-import DataCon ( DataCon, dataConId )
-import Id ( Id, idType, idName, mkWildId, mkUserId )
-import Const ( Literal(..) )
+import CoreUtils ( exprType, mkInlineMe )
+import Id ( Id, idType, idName, mkVanillaGlobal, mkSysLocal,
+ setInlinePragma )
+import IdInfo ( vanillaIdInfo )
+import Literal ( Literal(..) )
+import Module ( Module, moduleUserString )
import Name ( mkGlobalName, nameModule, nameOccName, getOccString,
- mkForeignExportOcc,
- NamedThing(..), Provenance(..), ExportFlag(..)
+ mkForeignExportOcc, isLocalName,
+ NamedThing(..),
)
-import PrelVals ( realWorldPrimId )
-import PrelInfo ( deRefStablePtr_NAME, bindIO_NAME, makeStablePtr_NAME )
-import Type ( splitAlgTyConApp_maybe,
- splitTyConApp_maybe, splitFunTys, splitForAllTys,
- Type, mkFunTys, mkForAllTys, mkTyConApp,
- mkTyVarTy, mkFunTy, splitAppTy
+import Type ( repType, eqType )
+import TcType ( Type, mkFunTys, mkForAllTys, mkTyConApp,
+ mkFunTy, applyTy,
+ tcSplitForAllTys, tcSplitFunTys, tcTyConAppArgs,
+ tcSplitTyConApp_maybe, tcSplitAppTy,
+ tcFunResultTy
)
-import PrimOp ( PrimOp(..) )
-import Var ( TyVar )
-import TysPrim ( realWorldStatePrimTy, addrPrimTy )
-import TysWiredIn ( unitTyCon, addrTy, stablePtrTyCon,
- unboxedTupleCon, addrDataCon
+
+import ForeignCall ( ForeignCall(..), CCallSpec(..),
+ Safety(..), playSafe,
+ CExportSpec(..),
+ CCallConv(..), ccallConvToInt
+ )
+import CStrings ( CLabelString )
+import TysWiredIn ( addrTy, unitTy, stablePtrTyCon )
+import TysPrim ( addrPrimTy )
+import PrelNames ( hasKey, ioTyConKey, deRefStablePtrName, newStablePtrName,
+ bindIOName, returnIOName
)
-import Unique
+import BasicTypes ( Activation( NeverActive ) )
+import ErrUtils ( addShortWarnLocLine )
import Outputable
+import Maybe ( fromJust )
\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]
- -> 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.
+type Binding = (Id, CoreExpr) -- No rec/nonrec structure;
+ -- the occurrence analyser will sort it all out
+
+dsForeigns :: Module
+ -> [TypecheckedForeignDecl]
+ -> DsM ( [Id] -- Foreign-exported binders;
+ -- we have to generate code to register these
+ , [Binding]
+ , SDoc -- Header file prototypes for
+ -- "foreign exported" functions.
+ , SDoc -- C stubs to use when calling
+ -- "foreign exported" functions.
+ , [FAST_STRING] -- headers that need to be included
+ -- into C code generated for this module
)
-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)
- | 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) ->
- 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) ->
- returnDs (acc_fi, fe:acc_fe, h $$ acc_h, c $$ acc_c)
+ combine (acc_feb, acc_f, acc_h, acc_c, acc_header)
+ (ForeignImport id _ spec depr loc)
+ = dsFImport mod_name id spec `thenDs` \(bs, h, c, hd) ->
+ warnDepr depr loc `thenDs` \_ ->
+ returnDs (acc_feb, bs ++ acc_f, h $$ acc_h, c $$ acc_c, hd ++ acc_header)
+
+ combine (acc_feb, acc_f, acc_h, acc_c, acc_header)
+ (ForeignExport id _ (CExport (CExportStatic ext_nm cconv)) depr loc)
+ = dsFExport mod_name id (idType id)
+ ext_nm cconv False `thenDs` \(feb, b, h, c) ->
+ warnDepr depr loc `thenDs` \_ ->
+ returnDs (feb:acc_feb, b : acc_f, h $$ acc_h, c $$ acc_c, acc_header)
+
+ warnDepr False _ = returnDs ()
+ warnDepr True loc = dsWarn (addShortWarnLocLine loc msg)
where
- isForeignImport =
- case imp_exp of
- FoImport _ -> True
- _ -> False
+ msg = ptext SLIT("foreign declaration uses deprecated non-standard syntax")
+\end{code}
- isForeignLabel =
- case imp_exp of
- FoLabel -> True
- _ -> False
- (FoImport uns) = imp_exp
-
-\end{code}
+%************************************************************************
+%* *
+\subsection{Foreign import}
+%* *
+%************************************************************************
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 -- Type of foreign import.
- -> 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
+However, we create a worker/wrapper pair, thus:
- arg_exprs = map (Var) args
+ 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# #)}})
- is_io_action =
- case mbIoDataCon of
- Nothing -> False
- _ -> True
- 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) ->
- (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
+ fw s x# = ccall f s x#
- -- 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 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.
- the_ccall_op = CCallOp label False (not may_not_gc) cconv
+\begin{code}
+dsFImport :: Module
+ -> Id
+ -> ForeignImport
+ -> DsM ([Binding], SDoc, SDoc, [FAST_STRING])
+dsFImport modName id (CImport cconv safety header lib spec) =
+ dsCImport modName id spec cconv safety `thenDs` \(ids, h, c) ->
+ returnDs (ids, h, c, if _NULL_ header then [] else [header])
+ -- FIXME: the `lib' field is needed for .NET ILX generation when invoking
+ -- routines that are external to the .NET runtime, but GHC doesn't
+ -- support such calls yet; if `_NULL_ lib', the value was not given
+dsFImport modName id (DNImport spec) =
+ dsFCall modName id (DNCall spec) `thenDs` \(ids, h, c) ->
+ returnDs (ids, h, c, [])
+
+dsCImport :: Module
+ -> Id
+ -> CImportSpec
+ -> CCallConv
+ -> Safety
+ -> DsM ([Binding], SDoc, SDoc)
+dsCImport modName id (CLabel cid) _ _ =
+ ASSERT(fromJust res_ty `eqType` addrPrimTy) -- typechecker ensures this
+ returnDs ([(id, rhs)], empty, empty)
+ where
+ (resTy, foRhs) = resultWrapper (idType id)
+ rhs = foRhs (mkLit (MachLabel cid))
+dsCImport modName id (CFunction target) cconv safety =
+ dsFCall modName id (CCall (CCallSpec target cconv safety))
+dsCImport modName id CWrapper cconv _ =
+ dsFExportDynamic modName id cconv
+\end{code}
- the_prim_app = mkPrimApp the_ccall_op (final_args :: [CoreArg])
- body = foldr ($) (res_wrapper the_prim_app) arg_wrappers
+%************************************************************************
+%* *
+\subsection{Foreign calls}
+%* *
+%************************************************************************
- the_body
- | not is_io_action = body
- | otherwise = Lam old_s body
+\begin{code}
+dsFCall mod_Name fn_id fcall
+ = let
+ ty = idType fn_id
+ (tvs, fun_ty) = tcSplitForAllTys ty
+ (arg_tys, io_res_ty) = tcSplitFunTys fun_ty
+ -- Must use tcSplit* functions because we want to
+ -- see that (IO t) in the corner
in
- newSysLocalDs (coreExprType the_body) `thenDs` \ ds ->
+ newSysLocalsDs arg_tys `thenDs` \ args ->
+ mapAndUnzipDs unboxArg (map Var args) `thenDs` \ (val_args, arg_wrappers) ->
+
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)
- in
- returnDs (NonRec nm fo_rhs)
-\end{code}
+ work_arg_ids = [v | Var v <- val_args] -- All guaranteed to be vars
-Given the type of a foreign import declaration, split it up into
-its constituent parts.
+ -- These are the ids we pass to boxResult, which are used to decide
+ -- whether to touch# an argument after the call (used to keep
+ -- ForeignObj#s live across a 'safe' foreign import).
+ maybe_arg_ids | unsafe_call fcall = work_arg_ids
+ | otherwise = []
+ in
+ boxResult maybe_arg_ids io_res_ty `thenDs` \ (ccall_result_ty, res_wrapper) ->
-\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
+ getUniqueDs `thenDs` \ ccall_uniq ->
+ getUniqueDs `thenDs` \ work_uniq ->
+ let
+ -- Build the worker
+ worker_ty = mkForAllTys tvs (mkFunTys (map idType work_arg_ids) ccall_result_ty)
+ the_ccall_app = mkFCall ccall_uniq fcall val_args ccall_result_ty
+ work_rhs = mkLams tvs (mkLams work_arg_ids the_ccall_app)
+ work_id = mkSysLocal SLIT("$wccall") work_uniq worker_ty
+
+ -- Build the wrapper
+ work_app = mkApps (mkVarApps (Var work_id) tvs) val_args
+ wrapper_body = foldr ($) (res_wrapper work_app) arg_wrappers
+ wrap_rhs = mkInlineMe (mkLams (tvs ++ args) wrapper_body)
+ in
+ returnDs ([(work_id, work_rhs), (fn_id, wrap_rhs)], empty, empty)
+unsafe_call (CCall (CCallSpec _ _ safety)) = playSafe safety
+unsafe_call (DNCall _) = False
\end{code}
-foreign labels
-\begin{code}
-dsFLabel :: Id -> ExtName -> DsM CoreBind
-dsFLabel nm ext_name = returnDs (NonRec nm fo_rhs)
- where
- fo_rhs = mkConApp addrDataCon [mkLit (MachLitLit enm addrPrimTy)]
- enm =
- case ext_name of
- ExtName f _ -> f
- Dynamic -> panic "dsFLabel: Dynamic - shouldn't ever happen."
-
-\end{code}
+%************************************************************************
+%* *
+\subsection{Foreign export}
+%* *
+%************************************************************************
-The function that does most of the work for 'foreign export' declarations.
-(see below for the boilerplate code a 'foreign export' declaration expands
+The function that does most of the work for `@foreign export@' declarations.
+(see below for the boilerplate code a `@foreign export@' declaration expands
into.)
-For each 'foreign export foo' in a module M we generate:
-
-* a C function 'foo', which calls
-* a Haskell stub 'M.$ffoo', which calls
-
-the user-written Haskell function 'M.foo'.
+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.
- -> ExtName
- -> CallConv
- -> Bool -- True => invoke IO action that's hanging off
- -- the first argument's stable pointer
- -> DsM ( CoreBind
+dsFExport :: Module
+ -> Id -- Either the exported Id,
+ -- or the foreign-export-dynamic constructor
+ -> Type -- The type of the thing callable from C
+ -> CLabelString -- The name to export to C land
+ -> CCallConv
+ -> Bool -- True => foreign export dynamic
+ -- so invoke IO action that's hanging off
+ -- the first argument's stable pointer
+ -> DsM ( Id -- The foreign-exported Id
+ , Binding
, SDoc
, SDoc
)
-dsFExport i ty ext_name cconv isDyn =
- getUniqueDs `thenDs` \ uniq ->
- getSrcLocDs `thenDs` \ src_loc ->
- let
- f_helper_glob = mkUserId helper_name helper_ty
- where
- name = idName i
- mod = 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 ->
+dsFExport mod_name fn_id ty ext_name cconv isDyn
+ = -- BUILD THE returnIO WRAPPER, if necessary
+ -- Look at the result type of the exported function, orig_res_ty
+ -- If it's IO t, return (\x.x, IO t, t)
+ -- If it's plain t, return (\x.returnIO x, IO t, t)
+ (case tcSplitTyConApp_maybe orig_res_ty of
+ -- We must use tcSplit here so that we see the (IO t) in
+ -- the type. [IO t is transparent to plain splitTyConApp.]
+
+ Just (ioTyCon, [res_ty])
+ -> ASSERT( ioTyCon `hasKey` ioTyConKey )
+ -- The function already returns IO t
+ returnDs (\body -> body, orig_res_ty, res_ty)
+
+ other -> -- The function returns t, so wrap the call in returnIO
+ dsLookupGlobalValue returnIOName `thenDs` \ retIOId ->
+ returnDs (\body -> mkApps (Var retIOId) [Type orig_res_ty, body],
+ tcFunResultTy (applyTy (idType retIOId) orig_res_ty),
+ -- We don't have ioTyCon conveniently to hand
+ orig_res_ty)
+
+ ) `thenDs` \ (return_io_wrapper, -- Either identity or returnIO
+ io_res_ty, -- IO t
+ res_ty) -> -- t
+
+
+ -- BUILD THE deRefStablePtr WRAPPER, if necessary
(if isDyn then
newSysLocalDs stbl_ptr_ty `thenDs` \ stbl_ptr ->
newSysLocalDs stbl_ptr_to_ty `thenDs` \ stbl_value ->
- dsLookupGlobalValue deRefStablePtr_NAME `thenDs` \ deRefStablePtrId ->
+ dsLookupGlobalValue deRefStablePtrName `thenDs` \ deRefStablePtrId ->
+ dsLookupGlobalValue bindIOName `thenDs` \ bindIOId ->
let
the_deref_app = mkApps (Var deRefStablePtrId)
[ Type stbl_ptr_to_ty, Var stbl_ptr ]
- in
- newSysLocalDs (coreExprType 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 ->
- let
- stbl_app = \ cont ->
- bindNonRec x_cont (mkLams [stbl_value] cont) $
- bindNonRec x_deref_app the_deref_app
- (mkApps (Var bindIOId)
- [ Type stbl_ptr_to_ty
- , Type res_ty
- , Var x_deref_app
- , Var x_cont])
+
+ stbl_app cont = mkApps (Var bindIOId)
+ [ Type stbl_ptr_to_ty
+ , Type res_ty
+ , the_deref_app
+ , mkLams [stbl_value] cont]
in
returnDs (stbl_value, stbl_app, stbl_ptr)
else
- returnDs (i,
+ returnDs (fn_id,
\ body -> body,
panic "stbl_ptr" -- should never be touched.
- )) `thenDs` \ (i, getFun_wrapper, stbl_ptr) ->
- let
- wrapper_args
- | isDyn = stbl_ptr:fe_args
- | otherwise = fe_args
+ )) `thenDs` \ (i, getFun_wrapper, stbl_ptr) ->
- wrapper_arg_tys
- | isDyn = stbl_ptr_ty:helper_arg_tys
- | otherwise = helper_arg_tys
- the_app =
- getFun_wrapper $
- mkApps (Var i) (map (Type . mkTyVarTy) tvs ++ map Var fe_args)
- in
- getModuleAndGroupDs `thenDs` \ (mod,_) ->
+ -- BUILD THE HELPER
+ getModuleDs `thenDs` \ mod ->
getUniqueDs `thenDs` \ uniq ->
+ getSrcLocDs `thenDs` \ src_loc ->
+ newSysLocalsDs fe_arg_tys `thenDs` \ fe_args ->
let
- the_body = mkLams (tvs ++ wrapper_args) the_app
+ wrapper_args | isDyn = stbl_ptr:fe_args
+ | otherwise = fe_args
- c_nm =
- case ext_name of
- ExtName fs _ -> fs
- Dynamic -> panic "dsFExport: Dynamic - shouldn't ever happen."
+ wrapper_arg_tys | isDyn = stbl_ptr_ty:fe_arg_tys
+ | otherwise = fe_arg_tys
- (h_stub, c_stub) = fexportEntry c_nm f_helper_glob wrapper_arg_tys the_result_ty cconv isDyn
+ helper_ty = mkForAllTys tvs $
+ mkFunTys wrapper_arg_tys io_res_ty
+
+ f_helper_glob = mkVanillaGlobal helper_name helper_ty vanillaIdInfo
+ where
+ name = idName fn_id
+ mod
+ | isLocalName name = mod_name
+ | otherwise = nameModule name
+
+ occ = mkForeignExportOcc (nameOccName name)
+ helper_name = mkGlobalName uniq mod occ src_loc
+
+ the_app = getFun_wrapper (return_io_wrapper (mkVarApps (Var i) (tvs ++ fe_args)))
+ the_body = mkLams (tvs ++ wrapper_args) the_app
+
+ (h_stub, c_stub) = fexportEntry (moduleUserString mod)
+ ext_name f_helper_glob
+ wrapper_arg_tys res_ty cconv isDyn
in
- returnDs (NonRec f_helper_glob the_body, h_stub, c_stub)
+ returnDs (f_helper_glob, (f_helper_glob, the_body), h_stub, c_stub)
where
+ (tvs,sans_foralls) = tcSplitForAllTys ty
+ (fe_arg_tys', orig_res_ty) = tcSplitFunTys sans_foralls
+ -- We must use tcSplits here, because we want to see
+ -- the (IO t) in the corner of the type!
- (tvs,sans_foralls) = splitForAllTys ty
- (fe_arg_tys', io_res) = splitFunTys sans_foralls
-
-
- Just (ioTyCon, [res_ty]) = splitTyConApp_maybe io_res
-
- (_, stbl_ptr_ty') = splitForAllTys stbl_ptr_ty
- (_, stbl_ptr_to_ty) = splitAppTy stbl_ptr_ty'
-
- fe_arg_tys
- | isDyn = tail fe_arg_tys'
- | otherwise = fe_arg_tys'
-
- (stbl_ptr_ty, helper_arg_tys) =
- case fe_arg_tys' of
- (x:xs) | isDyn -> (x,xs)
- ls -> (error "stbl_ptr_ty", ls)
+ fe_arg_tys | isDyn = tail fe_arg_tys'
+ | otherwise = fe_arg_tys'
- helper_ty =
- mkForAllTys tvs $
- mkFunTys arg_tys io_res
- where
- arg_tys
- | isDyn = stbl_ptr_ty : helper_arg_tys
- | otherwise = helper_arg_tys
+ stbl_ptr_ty | isDyn = head fe_arg_tys'
+ | otherwise = error "stbl_ptr_ty"
- the_result_ty =
- case splitTyConApp_maybe io_res of
- Just (_,[res_ty]) ->
- case splitTyConApp_maybe res_ty of
- Just (tc,_) | getUnique tc /= getUnique unitTyCon -> Just res_ty
- _ -> Nothing
- _ -> Nothing
-
+ (_, stbl_ptr_ty') = tcSplitForAllTys stbl_ptr_ty
+ (_, stbl_ptr_to_ty) = tcSplitAppTy stbl_ptr_ty'
+ -- Again, stable pointers are just newtypes,
+ -- so we must see them! Hence tcSplit*
\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{verbatim}
-foreign export stdcall f :: (Addr -> Int -> IO Int) -> IO Addr
+foreign export dynamic f :: (Addr -> Int -> IO Int) -> IO Addr
--- Haskell-visible constructor, which is generated from the
--- above:
+-- Haskell-visible constructor, which is generated from the above:
+-- SUP: No check for NULL from createAdjustor anymore???
f :: (Addr -> Int -> IO Int) -> IO Addr
-f cback = IO ( \ s1# ->
- case makeStablePtr# cback s1# of { StateAndStablePtr# s2# sp# ->
- case _ccall_ "mkAdjustor" sp# ``f_helper'' s2# of
- StateAndAddr# s3# a# ->
- case addr2Int# a# of
- 0# -> IOfail s# err
- _ ->
- let
- a :: Addr
- a = A# a#
- in
- IOok s3# a)
+f cback =
+ bindIO (newStablePtr cback)
+ (\StablePtr sp# -> IO (\s1# ->
+ case _ccall_ createAdjustor cconv sp# ``f_helper'' s1# of
+ (# s2#, a# #) -> (# s2#, A# a# #)))
foreign export "f_helper" f_helper :: StablePtr (Addr -> Int -> IO Int) -> Addr -> Int -> IO Int
-- `special' foreign export that invokes the closure pointed to by the
\end{verbatim}
\begin{code}
-dsFExportDynamic :: Id
- -> Type -- Type of foreign export.
- -> ExtName
- -> CallConv
- -> DsM (CoreBind, CoreBind, SDoc, SDoc)
-dsFExportDynamic i ty ext_name cconv =
- newSysLocalDs ty `thenDs` \ fe_id ->
+dsFExportDynamic :: Module
+ -> Id
+ -> CCallConv
+ -> DsM ([Binding], SDoc, SDoc)
+dsFExportDynamic mod_name id 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
+ fe_nm = _PK_ (moduleUserString mod_name ++ "_" ++ toCName fe_id)
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 ->
- dsLookupGlobalValue makeStablePtr_NAME `thenDs` \ makeStablePtrId ->
+ dsFExport mod_name id export_ty fe_nm cconv True `thenDs` \ (feb, fe, h_code, c_code) ->
+ newSysLocalDs arg_ty `thenDs` \ cback ->
+ dsLookupGlobalValue newStablePtrName `thenDs` \ newStablePtrId ->
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 = mkApps (Var newStablePtrId) [ Type arg_ty, Var cback ]
in
- newSysLocalDs mk_stbl_ptr_app_ty `thenDs` \ x_mk_stbl_ptr_app ->
- dsLookupGlobalValue bindIO_NAME `thenDs` \ bindIOId ->
+ dsLookupGlobalValue bindIOName `thenDs` \ bindIOId ->
newSysLocalDs (mkTyConApp stablePtrTyCon [arg_ty]) `thenDs` \ stbl_value ->
let
- stbl_app = \ x_cont cont ret_ty ->
- bindNonRec x_cont cont $
- bindNonRec x_mk_stbl_ptr_app mk_stbl_ptr_app $
- (mkApps (Var bindIOId)
- [ Type (mkTyConApp stablePtrTyCon [arg_ty])
- , Type ret_ty
- , Var x_mk_stbl_ptr_app
- , Var x_cont
- ])
+ stbl_app cont ret_ty
+ = mkApps (Var bindIOId)
+ [ Type (mkTyConApp stablePtrTyCon [arg_ty])
+ , Type ret_ty
+ , mk_stbl_ptr_app
+ , cont
+ ]
{-
The arguments to the external function which will
to be entered using an external calling convention
(stdcall, ccall).
-}
- adj_args = [ mkLit (mkMachInt (fromInt (callConvToInt cconv)))
+ adj_args = [ mkIntLitInt (ccallConvToInt cconv)
, Var stbl_value
- , mkLit (MachLitLit (_PK_ fe_nm) addrPrimTy)
+ , mkLit (MachLabel fe_nm)
]
-- name of external entry point providing these services.
-- (probably in the RTS.)
adjustor = SLIT("createAdjustor")
in
- dsCCall adjustor adj_args False False addrTy `thenDs` \ ccall_adj ->
- let ccall_adj_ty = coreExprType 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)
- (Var x_ccall_adj)
- in
- newSysLocalDs (coreExprType ccall_io_adj) `thenDs` \ x_ccall_io_adj ->
- let io_app = mkLams tvs $
+ dsCCall adjustor adj_args PlayRisky False io_res_ty `thenDs` \ ccall_adj ->
+ -- PlayRisky: the adjustor doesn't allocate in the Haskell heap or do a callback
+ let ccall_adj_ty = exprType ccall_adj
+ ccall_io_adj = mkLams [stbl_value] $
+ Note (Coerce io_res_ty ccall_adj_ty)
+ ccall_adj
+ io_app = mkLams tvs $
mkLams [cback] $
- stbl_app x_ccall_io_adj ccall_io_adj addrTy
+ stbl_app ccall_io_adj res_ty
+ fed = (id `setInlinePragma` NeverActive, io_app)
+ -- Never inline the f.e.d. function, because the litlit
+ -- might not be in scope in other modules.
in
- returnDs (NonRec i io_app, fe, h_code, c_code)
+ returnDs ([fed, fe], h_code, c_code)
where
- (tvs,sans_foralls) = splitForAllTys ty
- ([arg_ty], io_res) = splitFunTys sans_foralls
-
- Just (ioTyCon, [res_ty]) = splitTyConApp_maybe io_res
-
- export_ty = mkFunTy (mkTyConApp stablePtrTyCon [arg_ty]) arg_ty
+ ty = idType id
+ (tvs,sans_foralls) = tcSplitForAllTys ty
+ ([arg_ty], io_res_ty) = tcSplitFunTys sans_foralls
+ [res_ty] = tcTyConAppArgs io_res_ty
+ -- Must use tcSplit* to see the (IO t), which is a newtype
+ export_ty = mkFunTy (mkTyConApp stablePtrTyCon [arg_ty]) arg_ty
toCName :: Id -> String
toCName i = showSDoc (pprCode CStyle (ppr (idName i)))
-
\end{code}
%*
using the hugs/ghc rts invocation API.
\begin{code}
-fexportEntry :: FAST_STRING
+fexportEntry :: String
+ -> FAST_STRING
-> Id
-> [Type]
- -> Maybe Type
- -> CallConv
+ -> Type
+ -> CCallConv
-> Bool
-> (SDoc, SDoc)
-fexportEntry c_nm helper args res cc isDyn = (header_bits, c_bits)
+fexportEntry mod_nm c_nm helper args res_ty cc isDyn = (header_bits, c_bits)
where
-- name of the (Haskell) helper function generated by the desugarer.
h_nm = ppr helper <> text "_closure"
-- create the application + perform it.
, text "rc=rts_evalIO" <>
parens (foldl appArg (text "(StgClosure*)&" <> h_nm) (zip args c_args) <> comma <> text "&ret") <> semi
- , returnResult
+ , text "rts_checkSchedStatus" <> parens (doubleQuotes (ptext c_nm)
+ <> comma <> text "rc") <> semi
+ , text "return" <> return_what <> semi
, rbrace
]
cParamTypes = map showStgType real_args
- cResType =
- case res of
- Nothing -> text "void"
- Just t -> showStgType t
+ res_ty_is_unit = res_ty `eqType` unitTy -- Look through any newtypes
+
+ cResType | res_ty_is_unit = text "void"
+ | otherwise = showStgType res_ty
- pprCconv
- | cc == cCallConv = empty
- | otherwise = pprCallConv cc
+ pprCconv = case cc of
+ CCallConv -> empty
+ StdCallConv -> ppr cc
declareResult = text "HaskellObj ret;"
mkExtern ty nm = text "extern" <+> ty <+> nm <> semi
- returnResult =
- text "rts_checkSchedStatus" <>
- parens (doubleQuotes (ptext c_nm) <> comma <> text "rc") <> semi $$
- (case res of
- Nothing -> text "return"
- Just _ -> text "return" <> parens (res_name)) <> semi
-
- res_name =
- case res of
- Nothing -> empty
- Just t -> unpackHObj t <> parens (text "ret")
+ return_what | res_ty_is_unit = empty
+ | otherwise = parens (unpackHObj res_ty <> parens (text "ret"))
c_args = mkCArgNames 0 args
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)
+ = case cc of
+ CCallConv | isDyn -> ( text "a0" : text "a_" : mkCArgNames 1 (tail args)
+ , head args : addrTy : tail args)
+ other -> (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 "Hs" <> 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
+ tc = case tcSplitTyConApp_maybe (repType t) of
Just (tc,_) -> tc
Nothing -> pprPanic "showFFIType" (ppr t)
\end{code}
projects / ghc-hetmet.git / blobdiff