From ce3cab1dc3f3d03d43cf1b8cfc848c1ccaa00a84 Mon Sep 17 00:00:00 2001
From: sof <unknown>
Date: Fri, 14 Aug 1998 12:09:40 +0000
Subject: [PATCH] [project @ 1998-08-14 12:09:33 by sof] Painfully desugaring
 foreign decls

---
 ghc/compiler/deSugar/Desugar.lhs   |  19 +-
 ghc/compiler/deSugar/DsCCall.lhs   |  29 +-
 ghc/compiler/deSugar/DsExpr.lhs    |  17 +-
 ghc/compiler/deSugar/DsForeign.lhs | 808 +++++++++++++++++++++++++++++
 ghc/compiler/deSugar/DsMonad.lhs   |  17 +-
 ghc/compiler/deSugar/MatchLit.lhs  |   4 +-
 6 files changed, 867 insertions(+), 27 deletions(-)
 create mode 100644 ghc/compiler/deSugar/DsForeign.lhs

diff --git a/ghc/compiler/deSugar/Desugar.lhs b/ghc/compiler/deSugar/Desugar.lhs
index 61ce1e657500..6e02ef831f7c 100644
--- a/ghc/compiler/deSugar/Desugar.lhs
+++ b/ghc/compiler/deSugar/Desugar.lhs
@@ -10,11 +10,13 @@ module Desugar ( deSugar, pprDsWarnings ) where
 
 import CmdLineOpts	( opt_D_dump_ds )
 import HsSyn		( MonoBinds )
-import TcHsSyn		( TypecheckedMonoBinds )
+import TcHsSyn		( TypecheckedMonoBinds, TypecheckedForeignDecl )
+
 import CoreSyn
 import PprCore		( pprCoreBindings )
 import DsMonad
 import DsBinds		( dsMonoBinds )
+import DsForeign	( dsForeigns )
 import DsUtils
 
 import Bag		( isEmptyBag )
@@ -35,11 +37,13 @@ start.
 deSugar :: UniqSupply		-- name supply
 	-> Module		-- module name
 	-> TypecheckedMonoBinds
-	-> IO [CoreBinding]	-- output
+	-> [TypecheckedForeignDecl]
+	-> IO ([CoreBinding], SDoc, SDoc, SDoc) -- output
 
-deSugar us mod_name all_binds
+deSugar us mod_name all_binds fo_decls
   = let
 	(us1, us2) = splitUniqSupply us
+	(us3, us4) = splitUniqSupply us2
 
         module_and_group = (mod_name, grp_name)
 	grp_name  = case opt_SccGroup of
@@ -49,7 +53,12 @@ deSugar us mod_name all_binds
 	(core_prs, ds_warns) = initDs us1 nullIdEnv module_and_group 
 			       (dsMonoBinds opt_SccProfilingOn all_binds [])
 
-	ds_binds = liftCoreBindings us2 [Rec core_prs]
+	((fi_binds, fe_binds, hc_code, h_code, c_code), ds_warns2) = 
+	           initDs us3 nullIdEnv module_and_group 
+			 (dsForeigns fo_decls)
+
+	ds_binds' = liftCoreBindings us4 [Rec (core_prs)]
+	ds_binds  = fi_binds ++ ds_binds' ++ fe_binds
     in
 
 	-- Display any warnings
@@ -63,5 +72,5 @@ deSugar us mod_name all_binds
     dumpIfSet opt_D_dump_ds "Desugared:"
 	(pprCoreBindings ds_binds)	>>
 
-    return ds_binds    
+    return (ds_binds, hc_code, h_code, c_code)
 \end{code}
diff --git a/ghc/compiler/deSugar/DsCCall.lhs b/ghc/compiler/deSugar/DsCCall.lhs
index 91f0101ed321..73630c661ce6 100644
--- a/ghc/compiler/deSugar/DsCCall.lhs
+++ b/ghc/compiler/deSugar/DsCCall.lhs
@@ -4,7 +4,14 @@
 \section[DsCCall]{Desugaring \tr{_ccall_}s and \tr{_casm_}s}
 
 \begin{code}
-module DsCCall ( dsCCall ) where
+module DsCCall 
+	( 
+	   dsCCall 
+	,  getIoOkDataCon
+	,  unboxArg
+	,  boxResult
+	,  can'tSeeDataConsPanic
+	) where
 
 #include "HsVersions.h"
 
@@ -19,6 +26,7 @@ import Id		( Id, dataConArgTys, idType )
 import Maybes		( maybeToBool )
 import PrelVals		( packStringForCId )
 import PrimOp		( PrimOp(..) )
+import CallConv
 import Type		( isUnpointedType, splitAlgTyConApp_maybe, 
 			  splitTyConApp_maybe, splitFunTys, splitForAllTys,
 			  Type
@@ -82,13 +90,13 @@ dsCCall label args may_gc is_asm io_result_ty
     mapAndUnzipDs unboxArg args	`thenDs` \ (unboxed_args, arg_wrappers) ->
     let
 	 final_args = Var old_s : unboxed_args
-	 (ioOkDataCon, result_ty) = getIoOkDataCon io_result_ty
+	 (ioOkDataCon, _, result_ty) = getIoOkDataCon io_result_ty
     in
 
     boxResult ioOkDataCon result_ty `thenDs` \ (final_result_ty, res_wrapper) ->
 
     let
-	the_ccall_op = CCallOp label is_asm may_gc
+	the_ccall_op = CCallOp (Just label) is_asm may_gc cCallConv
 			       (map coreExprType final_args)
 			       final_result_ty
     in
@@ -121,7 +129,6 @@ unboxArg arg
 
   -- Strings
   | arg_ty == stringTy
-  -- ToDo (ADR): - allow synonyms of Strings too?
   = newSysLocalDs byteArrayPrimTy		`thenDs` \ prim_arg ->
     mkAppDs (Var packStringForCId) [VarArg arg]	`thenDs` \ pack_appn ->
     returnDs (Var prim_arg,
@@ -131,7 +138,7 @@ unboxArg arg
 
   | null data_cons
     -- oops: we can't see the data constructors!!!
-  = can't_see_datacons_error "argument" arg_ty
+  = can'tSeeDataConsPanic "argument" arg_ty
 
   -- Byte-arrays, both mutable and otherwise; hack warning
   | is_data_type &&
@@ -174,8 +181,8 @@ unboxArg arg
     maybe_arg2_tycon = splitTyConApp_maybe data_con_arg_ty2
     Just (arg2_tycon,_) = maybe_arg2_tycon
 
-can't_see_datacons_error thing ty
-  = pprPanic "ERROR: Can't see the data constructor(s) for _ccall_/_casm_ "
+can'tSeeDataConsPanic thing ty
+  = pprPanic "ERROR: Can't see the data constructor(s) for _ccall_/_casm_/foreign declaration"
 	     (hcat [text thing, text "; type: ", ppr ty, text "(try compiling with -fno-prune-tydecls ..)\n"])
 \end{code}
 
@@ -189,7 +196,7 @@ boxResult :: Id				-- IOok constructor
 boxResult ioOkDataCon result_ty
   | null data_cons
   -- oops! can't see the data constructors
-  = can't_see_datacons_error "result" result_ty
+  = can'tSeeDataConsPanic "result" result_ty
 
   -- Data types with a single constructor, which has a single, primitive-typed arg
   | (maybeToBool maybe_data_type) &&				-- Data type
@@ -257,8 +264,8 @@ newtype IO a = IO (State# RealWorld -> IOResult a)
 the constructor IO has type (State# RealWorld -> IOResult a) -> IO a
 
 \begin{code}
-getIoOkDataCon :: Type 		-- IO t
-	       -> (Id,Type)	-- Returns (IOok, t)
+getIoOkDataCon :: Type 		 -- IO t
+	       -> (Id, Id, Type) -- Returns (IOok, IO, t)
 
 getIoOkDataCon io_ty
   = let 
@@ -271,7 +278,7 @@ getIoOkDataCon io_ty
 	Just (io_result_tycon, _)	= splitTyConApp_maybe io_result_ty
 	[ioOkDataCon,ioFailDataCon]     = tyConDataCons io_result_tycon
     in
-    (ioOkDataCon, t)
+    (ioOkDataCon, ioDataCon, t)
 \end{code}
 
 Another way to do it, more sensitive:
diff --git a/ghc/compiler/deSugar/DsExpr.lhs b/ghc/compiler/deSugar/DsExpr.lhs
index 1e374ce353ec..f44a90a29344 100644
--- a/ghc/compiler/deSugar/DsExpr.lhs
+++ b/ghc/compiler/deSugar/DsExpr.lhs
@@ -154,10 +154,10 @@ dsExpr (HsLitOut (HsFrac r) ty)
 -- others where we know what to do:
 
 dsExpr (HsLitOut (HsIntPrim i) _)
-  = if (i >= toInteger minInt && i <= toInteger maxInt) then
-    	returnDs (Lit (mkMachInt i))
-    else
-	error ("ERROR: Int constant " ++ show i ++ out_of_range_msg)
+  | i >= toInteger minInt && i <= toInteger maxInt 
+  = returnDs (Lit (mkMachInt (fromInteger i)))
+  | otherwise 
+  = error ("ERROR: Int constant " ++ show i ++ out_of_range_msg)
 
 dsExpr (HsLitOut (HsFloatPrim f) _)
   = returnDs (Lit (MachFloat f))
@@ -593,10 +593,13 @@ dsDo do_or_lc stmts return_id then_id zero_id result_ty
 		zero_expr  = TyApp (HsVar zero_id) [b_ty]
 		main_match = PatMatch pat (SimpleMatch (
 			     HsDoOut do_or_lc stmts return_id then_id zero_id result_ty locn))
+
 		the_matches
-		  = if failureFreePat pat
-		    then [main_match]
-		    else [main_match, PatMatch (WildPat a_ty) (SimpleMatch zero_expr)]
+		  | failureFreePat pat = [main_match]
+		  | otherwise	       = 
+			[ main_match
+		        , PatMatch (WildPat a_ty) (SimpleMatch zero_expr)
+			]
 	    in
 	    matchWrapper DoBindMatch the_matches match_msg
 				`thenDs` \ (binders, matching_code) ->
diff --git a/ghc/compiler/deSugar/DsForeign.lhs b/ghc/compiler/deSugar/DsForeign.lhs
new file mode 100644
index 000000000000..2a855aff37de
--- /dev/null
+++ b/ghc/compiler/deSugar/DsForeign.lhs
@@ -0,0 +1,808 @@
+%
+% (c) The AQUA Project, Glasgow University, 1998
+%
+\section[DsCCall]{Desugaring \tr{foreign} declarations}
+
+Expanding out @foreign import@ and @foreign export@ declarations.
+
+\begin{code}
+module DsForeign ( dsForeigns ) where
+
+
+#include "HsVersions.h"
+
+import CoreSyn
+
+import DsCCall		( getIoOkDataCon, boxResult, unboxArg,
+			  can'tSeeDataConsPanic
+			)
+import DsMonad
+import DsUtils
+
+import HsSyn		( ExtName(..), ForeignDecl(..), isDynamic )
+import CallConv
+import TcHsSyn		( maybeBoxedPrimType, TypecheckedForeignDecl )
+import CoreUtils	( coreExprType )
+import Id		( Id, dataConArgTys, idType, idName,
+			  mkVanillaId, dataConRawArgTys,
+			  dataConTyCon, mkIdVisible
+			)
+import IdInfo		( noIdInfo )
+import Literal		( Literal(..), mkMachInt )
+import Maybes		( maybeToBool )
+import Name		( nameString, occNameString, nameOccName, nameUnique )
+import PrelVals		( packStringForCId, eRROR_ID )
+import PrimOp		( PrimOp(..) )
+import Type		( isUnpointedType, splitAlgTyConApp_maybe, 
+			  splitTyConApp_maybe, splitFunTys, splitForAllTys,
+			  Type, mkFunTys, applyTy, mkForAllTys, mkTyConApp,
+			  typePrimRep, mkTyVarTy, mkFunTy, splitAppTy
+			)
+import PrimRep		( showPrimRepToUser, PrimRep(..) )
+import TyVar		( TyVar )
+import TyCon		( tyConDataCons )
+import TysPrim		( byteArrayPrimTy, realWorldStatePrimTy,
+			  byteArrayPrimTyCon, mutableByteArrayPrimTyCon,
+			  realWorldTy, addrPrimTy, mkStablePtrPrimTy,
+			  intPrimTy
+			)
+import TysWiredIn	( getStatePairingConInfo,
+			  unitDataCon, stringTy,
+			  realWorldStateTy, stateDataCon,
+			  isFFIArgumentTy, unitTy,
+			  addrTy, stablePtrTyCon,
+			  stateAndPtrPrimDataCon
+			)
+import Outputable
+\end{code}
+
+Desugaring of @foreign@ declarations is naturally split up into
+parts, an @import@ and an @export@  part. A @foreign import@ 
+declaration 
+
+  foreign import cc nm f :: prim_args -> IO prim_res
+
+is the same as
+
+  f :: prim_args -> IO prim_res
+  f a1 ... an = _ccall_ nm cc a1 ... an
+
+so we reuse the desugaring code in @DsCCall@ to deal with these.
+
+\begin{code}
+dsForeigns :: [TypecheckedForeignDecl] 
+	   -> DsM ( [CoreBinding]        -- desugared foreign imports
+                  , [CoreBinding]        -- helper functions for foreign exports
+		  , SDoc		 -- auxilliary code to emit into .hc file
+		  , SDoc		 -- Header file prototypes for "foreign exported" functions.
+		  , SDoc 		 -- C stubs to use when calling "foreign exported" funs.
+		  )
+dsForeigns fos = foldlDs combine ([],[],empty,empty,empty) fos
+ where
+  combine (acc_fi, acc_fe, acc_hc, acc_h, acc_c) fo@(ForeignDecl i imp_exp _ ext_nm cconv _) 
+    | isForeignImport = 
+        dsFImport i (idType i) uns ext_nm cconv  `thenDs` \ b -> 
+	returnDs (b:acc_fi, acc_fe, acc_hc, acc_h, acc_c)
+    | isDynamic ext_nm =
+        dsFExportDynamic i (idType i) ext_nm cconv  `thenDs` \ (fi,fe,hc,h,c) -> 
+	returnDs (fi:acc_fi, fe:acc_fe, hc $$ acc_hc, h $$ acc_h, c $$ acc_c)
+    | otherwise	       =
+        dsFExport i (idType i) ext_nm cconv False   `thenDs` \ (fe,hc,h,c) ->
+	returnDs (acc_fi, fe:acc_fe, hc $$ acc_hc, h $$ acc_h, c $$ acc_c)
+
+   where
+    isForeignImport = maybeToBool imp_exp
+    (Just uns)      = imp_exp
+
+\end{code}
+
+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.
+
+\begin{code}
+dsFImport :: Id
+	  -> Type		-- Type of foreign import.
+	  -> Bool		-- True <=> might cause Haskell GC
+	  -> ExtName
+	  -> CallConv
+	  -> DsM CoreBinding
+dsFImport nm ty may_not_gc ext_name cconv =
+    newSysLocalDs realWorldStatePrimTy	`thenDs` \ old_s ->
+    mkArgs ty				`thenDs` \ (tvs, args, io_res_ty)  ->
+    mapAndUnzipDs unboxArg args		`thenDs` \ (unboxed_args, arg_wrappers) ->
+    let
+	 final_args = Var old_s : unboxed_args
+	 (ioOkDataCon, ioDataCon, result_ty) = getIoOkDataCon io_res_ty
+    in
+    boxResult ioOkDataCon result_ty	`thenDs` \ (final_result_ty, res_wrapper) ->
+    let
+	label =
+	 case ext_name of
+	   Dynamic      -> Nothing
+	   ExtName fs _ -> Just fs
+
+	the_ccall_op = CCallOp label False (not may_not_gc) cconv
+			       (map coreExprType final_args)
+			       final_result_ty
+    in
+    mkPrimDs the_ccall_op (map VarArg final_args) `thenDs` \ the_prim_app ->
+    let
+	the_body = mkValLam [old_s]
+			    (foldr ($) (res_wrapper the_prim_app) arg_wrappers)
+    in
+    newSysLocalDs (coreExprType the_body) `thenDs` \ ds ->
+    let
+      io_app = mkValApp (mkTyApp (Var ioDataCon) [result_ty]) [VarArg ds]
+      fo_rhs = mkTyLam  tvs $
+	       mkValLam (map (\ (Var x) -> x) args)
+			(mkCoLetAny (NonRec ds the_body) io_app)
+    in
+    returnDs (NonRec nm fo_rhs)
+
+mkArgs :: Type -> DsM ([TyVar], [CoreExpr], Type)
+mkArgs ty = 
+  case splitFunTys sans_foralls of
+    (arg_tys, res_ty) -> 
+       newSysLocalsDs arg_tys  `thenDs` \ ds_args ->
+       returnDs (tvs, map Var ds_args, res_ty)
+  where
+   (tvs, sans_foralls) = splitForAllTys ty
+        
+\end{code}
+
+\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 (CoreBinding, SDoc, SDoc, SDoc)
+dsFExport i ty ext_name cconv isDyn =
+     newSysLocalDs  realWorldStatePrimTy	        `thenDs` \ s1 ->
+     newSysLocalDs  realWorldStatePrimTy	        `thenDs` \ s3 ->
+     newSysLocalDs  helper_ty			        `thenDs` \ f_helper ->
+     newSysLocalsDs helper_arg_tys		        `thenDs` \ helper_args ->
+     newSysLocalDs  res_ty			        `thenDs` \ v1 ->
+     unboxResult    the_prim_result_ty res_ty s3 v1     `thenDs` \ (state_and_prim_ty, unpack_result) ->
+     zipWithDs boxArg fe_arg_tys helper_args	        `thenDs` \ stuff ->
+     (if isDyn then 
+        newSysLocalDs realWorldStatePrimTy		`thenDs` \ s11 ->
+        newSysLocalDs stbl_ptr_ty			`thenDs` \ stbl_ptr ->
+	newSysLocalDs stbl_ptr_to_ty			`thenDs` \ f ->
+	mkPrimDs DeRefStablePtrOp
+	         [TyArg stbl_ptr_to_ty,
+		  VarArg (Var stbl_ptr),
+		  VarArg (Var s1)]			`thenDs` \ the_deref_app ->
+	let
+	 stbl_app = \ cont ->
+	    Case the_deref_app 
+		 (AlgAlts [(stateAndPtrPrimDataCon, [s11, f], cont)]
+			  NoDefault)
+        in
+	returnDs (f, stbl_app, s11, stbl_ptr)
+      else
+        returnDs (i, 
+	          \ body -> body,
+		  s1,
+		  panic "stbl_ptr"  -- should never be touched.
+		  ))					`thenDs` \ (i, getFun_wrapper, s2, stbl_ptr) ->
+     let
+      (boxed_args, arg_wrappers)  = unzip stuff
+
+      wrapper_args
+       | isDyn      = stbl_ptr:helper_args
+       | otherwise  = helper_args
+
+      wrapper_arg_tys
+       | isDyn      = stbl_ptr_ty:helper_arg_tys
+       | otherwise  = helper_arg_tys
+
+      fe_app   = mkGenApp (Var i) (map (TyArg . mkTyVarTy) tvs ++ map VarArg boxed_args)
+      the_app  = 
+        getFun_wrapper $
+        mkValApp (Note (Coerce io_result_ty io_res) fe_app)
+	         [VarArg s2]
+     in
+     newFailLocalDs  (coreExprType the_app)	`thenDs` \ wild ->
+     getModuleAndGroupDs			`thenDs` \ (mod,_) -> 
+     getUniqueDs				`thenDs` \ uniq ->
+     let
+
+      the_body = 
+	   mkTyLam  tvs		 $
+	   mkValLam wrapper_args $
+	   mkValLam [s1]	 $
+	   foldr ($) (perform_and_unpack) arg_wrappers
+
+      perform_and_unpack =
+         Case the_app (AlgAlts [(ioOkDataCon, [s3, v1], unpack_result)]
+		      (BindDefault wild err))
+
+      c_nm =
+        case ext_name of
+	  ExtName fs _ -> fs
+
+      full_msg = "Exception caught: " ++ _UNPK_ (nameString (idName i))
+      msg = NoRepStr (_PK_ full_msg)
+      err = mkApp (Var eRROR_ID) [state_and_prim_ty] [LitArg msg]
+
+      f_helper_glob = (mkIdVisible mod uniq f_helper)
+      (hc_stub, h_stub, c_stub) = fexportEntry c_nm f_helper_glob wrapper_arg_tys the_prim_result_ty cconv
+     in
+     returnDs (NonRec f_helper_glob the_body, hc_stub, h_stub, c_stub)
+  where
+   (tvs,sans_foralls)			  = splitForAllTys ty
+   (fe_arg_tys', io_res)	          = splitFunTys sans_foralls
+   (ioOkDataCon, ioDataCon, res_ty)       = getIoOkDataCon io_res
+
+   maybe_data_type 			  = splitAlgTyConApp_maybe res_ty
+   Just (tycon, tycon_arg_tys, data_cons) = maybe_data_type
+   (the_data_con : other_data_cons)       = data_cons
+
+   data_con_arg_tys		      = dataConArgTys the_data_con tycon_arg_tys
+   (prim_result_ty : other_args_tys)  = data_con_arg_tys
+
+   ioDataConTy				= idType ioDataCon
+   (io_tvs, ioDataConTy')               = splitForAllTys ioDataConTy
+   ([arg_ty], _) 		        = splitFunTys ioDataConTy'
+   io_result_ty				= applyTy (mkForAllTys io_tvs arg_ty) res_ty
+
+   (_, 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 (map unboxTy fe_arg_tys') of
+       (x:xs) | isDyn -> (x,xs)
+       ls	      -> (error "stbl_ptr_ty", ls)
+
+   helper_ty      =  
+	mkForAllTys tvs $
+	mkFunTys (arg_tys ++ [realWorldStatePrimTy])
+		 state_and_prim_ty
+        where
+	  arg_tys
+	   | isDyn	= stbl_ptr_ty : helper_arg_tys
+	   | otherwise  = helper_arg_tys
+
+   the_prim_result_ty
+     | null data_con_arg_tys   = Nothing
+     | otherwise	       = Just prim_result_ty
+
+   state_and_prim_ty
+     | (null other_data_cons) &&
+       (null data_con_arg_tys) = realWorldStateTy
+     | otherwise	       = snd (getStatePairingConInfo (unboxTy res_ty))
+\end{code}
+
+"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
+
+-- Haskell-visible constructor, which is generated from the
+-- above:
+
+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)
+
+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
+-- first argument.
+\end{verbatim}
+
+\begin{code}
+dsFExportDynamic :: Id
+		 -> Type		-- Type of foreign export.
+		 -> ExtName
+		 -> CallConv
+		 -> DsM (CoreBinding, CoreBinding, SDoc, SDoc, SDoc)
+dsFExportDynamic i ty 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), hc_code, h_code, c_code) ->
+     newSysLocalDs  realWorldStatePrimTy	         `thenDs` \ s1 ->
+     newSysLocalDs  realWorldStatePrimTy	         `thenDs` \ s2 ->
+     newSysLocalDs  realWorldStatePrimTy	         `thenDs` \ s3 ->
+     newSysLocalDs  arg_ty				 `thenDs` \ cback_arg ->
+     newSysLocalDs  arg_ty				 `thenDs` \ cback ->
+     newSysLocalDs  (mkStablePtrPrimTy arg_ty)		 `thenDs` \ stbl ->
+     newSysLocalDs  addrPrimTy				 `thenDs` \ addrPrim ->
+     newSysLocalDs  addrTy				 `thenDs` \ addr ->
+     mkPrimDs MakeStablePtrOp [TyArg arg_ty,
+			       VarArg (Var cback), 
+			       VarArg (Var s1)]	         `thenDs` \ mkStablePtr_app ->
+     mkPrimDs Addr2IntOp [VarArg (Var addrPrim)]         `thenDs` \ the_addr2Int_app ->
+     boxArg addrTy addrPrim				 `thenDs` \ (addr_result, addrPrim_wrapper) ->
+     let
+       (stateAndStablePtrPrimDataCon, _)	     = getStatePairingConInfo (mkStablePtrPrimTy arg_ty)
+       (stateAndAddrPrimDataCon, stateAndAddrPrimTy) = getStatePairingConInfo addrPrimTy
+
+       cc
+        | cconv == stdCallConv = 1
+	| otherwise	       = 0
+
+       ccall_args   = [Var s2, Lit (mkMachInt cc),
+		       Var stbl, 
+		       Lit (MachLitLit (_PK_ fe_nm) AddrRep)]
+
+       label	    = Just SLIT("createAdjustor")
+       the_ccall_op = CCallOp label False False{-won't GC-} cCallConv
+			      (map coreExprType ccall_args)
+			      stateAndAddrPrimTy
+     in
+     mkPrimDs the_ccall_op (map VarArg ccall_args)     `thenDs` \ the_ccall_app ->
+     mkConDs  ioOkDataCon  
+              [TyArg res_ty, VarArg (Var s3), VarArg (Var addr_result)]
+						       `thenDs` \ ioOkApp ->
+     newSysLocalDs intPrimTy			       `thenDs` \ default_val ->
+     let
+        the_mkStablePtr = \ cont ->
+          Case mkStablePtr_app
+	      (AlgAlts [(stateAndStablePtrPrimDataCon, [s2, stbl], cont)]
+		       NoDefault)
+
+        the_ccall = \ cont ->
+	  Case the_ccall_app 
+	       (AlgAlts [(stateAndAddrPrimDataCon, [s3, addrPrim], cont)]
+		        NoDefault)
+        the_addr2Int = \ cont ->
+	  Case the_addr2Int_app
+	       (PrimAlts [(mkMachInt 0, io_fail)]
+			 (BindDefault default_val cont))
+
+        io_fail	 = mkApp (Var eRROR_ID) [coreExprType wrap_res] [LitArg msg]
+        full_msg = "Exception caught: " ++ _UNPK_ (nameString (idName i))
+        msg	 = NoRepStr (_PK_ full_msg)
+
+        wrap_res = addrPrim_wrapper ioOkApp
+        the_body = 
+	  mkTyLam tvs          $
+	  mkValLam  [cback,s1] $
+	  the_mkStablePtr      $
+	  the_ccall            $
+          the_addr2Int  wrap_res
+          
+      in	       
+      newSysLocalDs (coreExprType the_body) `thenDs` \ ds ->
+      newSysLocalDs (mkFunTy realWorldStatePrimTy
+			     (coreExprType ioOkApp))  `thenDs` \ ap ->
+      let
+        io_app    = mkValApp (mkTyApp (Var ioDataCon) [res_ty]) [VarArg ap]
+	io_action = 
+	  mkTyLam tvs           $
+	  mkValLam  [cback_arg] $
+	  mkCoLetAny (NonRec ds the_body) $
+	  mkCoLetAny (NonRec ap (mkValApp (mkTyApp (Var ds) (map mkTyVarTy tvs)) [VarArg cback_arg])) $
+	  io_app
+      in
+      returnDs (NonRec i io_action, fe, hc_code, h_code, c_code)
+ where
+  (tvs,sans_foralls)		   = splitForAllTys ty
+  ([arg_ty], io_res)		   = splitFunTys sans_foralls
+  (ioOkDataCon, ioDataCon, res_ty) = getIoOkDataCon io_res
+
+  ioDataConTy			   = idType ioDataCon
+  (io_tvs, ioDataConTy')           = splitForAllTys ioDataConTy
+--  ([arg_ty], _) 		   = splitFunTys ioDataConTy'
+  io_result_ty			   = applyTy (mkForAllTys io_tvs arg_ty) res_ty
+
+  export_ty			   = mkFunTy (mkTyConApp stablePtrTyCon [arg_ty]) arg_ty
+
+toCName :: Id -> String
+toCName i = showSDoc (pprCode CStyle (ppr (idName i)))
+
+\end{code}
+
+%*
+%
+\subsection{Helper functions}
+%
+%*
+
+@boxArg@ boxes up an argument in preparation for calling
+a function that maybe expects a boxed version of it, i.e.,
+
+\begin{verbatim}
+boxArg Addr a# ==> let ds_foo :: Addr ; ds_foo = A# a# in f ...ds_foo..
+\end{verbatim}
+
+\begin{code}
+boxArg :: Type			     -- Expected type after possible boxing of arg.
+       -> Id			     -- The (unboxed) argument
+       -> DsM (Id,		     -- To pass as the actual, boxed argument
+	       CoreExpr -> CoreExpr  -- Wrapper to box the arg
+		)
+boxArg box_ty prim_arg
+  | isUnpointedType box_ty = returnDs (prim_arg, \body -> body)
+    -- Data types with a single constructor, 
+    -- which has a single, primitive-typed arg
+  | otherwise
+  = newSysLocalDs box_ty		`thenDs` \ box_arg ->
+    returnDs ( box_arg
+	     , Let (NonRec box_arg (mkCon box_data_con tys_applied [VarArg prim_arg]))
+	     )
+  where
+    maybe_boxed_prim_arg_ty  = maybeBoxedPrimType box_ty
+    (Just (_,tys_applied,_)) = splitAlgTyConApp_maybe box_ty
+    (Just (box_data_con, _)) = maybe_boxed_prim_arg_ty
+\end{code}
+
+@foreign export@ed functions may return a value back to the outside world.
+@unboxResult@ takes care of converting from the (boxed) value that the
+exported action returns to the (unboxed) value that is returned across
+the border.
+
+\begin{code}
+unboxResult :: Maybe Type	     -- the (unboxed) type we want to return (along with the state token)
+				     -- Nothing => no result, just the state token.
+	    -> Type		     -- the (boxed) type we have in our hand.
+            -> Id		     -- the state token
+            -> Id		     -- boxed arg
+	    -> DsM (Type,	     -- type of returned expression.
+		    CoreExpr)	     -- expr that unboxes result and returns state+unboxed result.
+
+unboxResult mb_res_uboxed_ty res_ty new_s v_boxed 
+ | not (maybeToBool mb_res_uboxed_ty) 
+ =   -- no result, just return state token
+    mkConDs stateDataCon [ TyArg realWorldTy
+			 , VarArg (Var new_s)] `thenDs` \ the_st ->
+    returnDs (realWorldStateTy, the_st)
+
+ | null data_cons
+  -- oops! can't see the data constructors
+ = can'tSeeDataConsPanic "result" res_ty
+
+ | (maybeToBool maybe_data_type) &&	    -- Data type
+   (null other_data_cons)	 &&	    --  - with one constructor,
+   isUnpointedType res_uboxed_ty  	    --  - and of primitive type.
+					    -- (Glasgow extension)
+ =
+   newSysLocalDs res_uboxed_ty	       `thenDs` \ v_unboxed ->
+   mkConDs state_and_prim_datacon 
+	   ((TyArg realWorldTy):map (TyArg ) tycon_arg_tys ++
+	    [ VarArg (Var new_s)
+	    , VarArg (Var v_unboxed)]) `thenDs` \ the_result ->
+   let
+    the_alt = (the_data_con, [v_unboxed], the_result)
+   in
+   returnDs (state_and_prim_ty,
+	     Case (Var v_boxed) (AlgAlts [the_alt] NoDefault))
+
+  | otherwise
+  = pprPanic "unboxResult: " (ppr res_ty)
+ where
+    (Just res_uboxed_ty)		   = mb_res_uboxed_ty
+
+    maybe_data_type 			   = splitAlgTyConApp_maybe res_ty
+    Just (tycon, tycon_arg_tys, data_cons) = maybe_data_type
+    (the_data_con : other_data_cons)       = data_cons
+
+    (state_and_prim_datacon, state_and_prim_ty) = getStatePairingConInfo res_uboxed_ty
+
+\end{code}
+
+Returned the unboxed type of a (primitive) type:
+
+\begin{code}
+unboxTy :: Type -> Type
+unboxTy ty
+ | isUnpointedType ty || (ty == unitTy) = ty
+ | otherwise	      = 
+     ASSERT( isFFIArgumentTy ty ) -- legal arg types subsume result types.
+     case splitTyConApp_maybe ty of
+        Just (tyc,ts) -> 
+		case (tyConDataCons tyc) of
+		  [dc] -> case (dataConArgTys dc ts) of
+			      [ubox]   -> ubox
+				-- HACK: for the array types, the prim type is
+				-- the second tycon arg.
+			      [_,ubox] -> ubox
+			      _	       -> pprPanic "unboxTy: " (ppr ty)
+		  _ ->  pprPanic "unboxTy: " (ppr ty)
+	_ ->  pprPanic "unboxTy: " (ppr ty)
+
+\end{code}
+
+%*
+%
+\subsection{Generating @foreign export@ stubs}
+%
+%*
+
+[Severe hack to get @foreign export@ off the ground:]
+
+For each @foreign export@ function, a C stub together with a @.hc@ stub
+is generated. The C stub enters the .hc stub, setting up the passing of
+parameters from C land to STG land through the use of global variables
+(don't worry, this just a temporary solution!). Ditto for the result.
+
+[
+The generation of .hc code will go once the transition is
+made over to the new rts. Hence the hack, instead of extending
+AbsCSyn to cope with the .hc code generated.
+]
+
+\begin{code}
+fexportEntry :: FAST_STRING -> Id -> [Type] -> Maybe Type -> CallConv -> (SDoc, SDoc, SDoc)
+fexportEntry c_nm helper args res cc =
+   ( paramArea $$ stopTemplate $$ startTemplate $$ vtblTemplate, h_code, c_code )
+ where
+  (h_code, c_code) = mkCStub c_nm h_stub_nm args res cc
+
+  paramArea = 
+    vcat (zipWith declVar ( res_ty : param_tys ) ( res_name : param_names ) )
+
+   -- name of the (Haskell) helper function generated by the desugarer.
+  h_nm	    = ppr helper
+  h_stub_nm = text foreign_export_prefix <> h_nm
+  closure   = h_nm <> text "_closure"
+
+  param_names = zipWith (\ i _ -> h_stub_nm <> text ('_':show i)) [1..] args
+  param_tys   = map (ppr.typePrimRep) args
+
+  (res_name, res_ty) = 
+    case res of
+      Nothing -> (empty, empty)
+      Just t  -> (h_stub_nm <> text "_res", ppr (typePrimRep t))
+
+  startTemplate =
+    vcat 
+      [ text "extern realWorldZh_closure;"
+      , ptext SLIT("STGFUN") <> parens (h_stub_nm)
+      , lbrace
+      ,  ptext SLIT("FUNBEGIN;")
+      ,  text  "RestoreAllStgRegs();"
+      ,  stackCheck param_names
+      ,  pushRetReg
+      ,  pushCont
+      ,  pushRealWorld
+      ,  vcat (map pushArg (reverse param_names))
+      ,  text "Node=" <> closure <> semi
+      ,  text "ENT_VIA_NODE();"   -- ticky count
+      ,  text "InfoPtr=(D_)(INFO_PTR(Node));"
+      ,  text "JMP_(ENTRY_CODE(InfoPtr));"
+      ,  text "FUNEND;"
+      , rbrace
+      ]
+
+  stopTemplate =
+    vcat
+      [ ptext SLIT("STGFUN") <> parens (text "stop" <> h_stub_nm <> text "DirectReturn")
+      , lbrace
+      ,  ptext SLIT("FUNBEGIN;")
+      ,  assignResult
+      ,  popRetReg
+      ,  text "#if defined(__STG_GCC_REGS__)"
+      ,  text "SaveAllStgRegs();"
+      ,  text "#else"
+      ,  text "SAVE_Hp = Hp;"
+      ,  text "SAVE_HpLim = HpLim;"
+      ,  text "#endif"
+      ,  text "JMP_(miniInterpretEnd);"
+      ,  text "FUNEND;"
+      , rbrace
+      ]
+
+  vtblTemplate =
+    vcat
+      [ text "const W_ vtbl_" <> h_stub_nm <> text "[] = {"
+      , vcat (punctuate comma (replicate 8 dir_ret))
+      , text "};"
+      ]
+   where
+    dir_ret = text "(W_)stop" <> h_stub_nm <> text "DirectReturn"
+
+  assignResult =
+    case res of
+      Nothing -> empty
+      Just _  -> res_name <> equals <> text "R3.i;" -- wrong
+
+  pushRetReg =
+    text "SpB -= BREL(1);" $$
+    text "*SpB = (W_)RetReg;"
+
+  popRetReg =
+    text "RetReg=(StgRetAddr)*SpB;" $$
+    text "SpB += BREL(1);"
+
+  pushCont =
+    text "RetReg=(StgRetAddr)UNVEC(stop" <> h_stub_nm <> 
+    text "DirectReturn,vtbl_" <> h_stub_nm <> text ");"
+
+  pushRealWorld =
+    text "SpB -= BREL(1);" $$
+    text "*SpB = (W_)realWorldZh_closure;"
+
+
+  pushArg nm = 
+     text "SpB -= BREL(1);" $$
+     text "*SpB = (W_)" <> nm <> semi
+
+  stackCheck args =
+     text "STK_CHK(LivenessReg,0," <> sz <> text ",0,0,0,0);"
+   where
+     sz = parens $
+          hsep $ punctuate (text " + ") (text "1":(map sizer args))
+
+     sizer x = text "BYTES_TO_STGWORDS" <> parens (text "sizeof" <> parens x)
+
+foreign_export_prefix :: String
+foreign_export_prefix = "__fexp_"
+
+mkCStub :: FAST_STRING -> SDoc -> [Type] -> Maybe Type -> CallConv -> (SDoc, SDoc)
+mkCStub c_nm h_stub_nm args res cc = 
+ ( hsep [ ptext SLIT("extern")
+	, cResType
+        , pprCconv
+	, ptext c_nm
+	, parens (hsep (punctuate comma (zipWith (<+>) stubParamTypes stubArgs)))
+	, semi
+	]
+ , vcat 
+     [ externDecls
+     , cResType
+     , pprCconv
+     , ptext c_nm <> parens (hsep (punctuate comma stubArgs))
+     , vcat (zipWith declVar stubParamTypes stubArgs)
+     , lbrace
+     ,  vcat (zipWith assignArgs param_names c_args)
+     ,  text "miniInterpret" <> parens (parens (text "StgFunPtr") <> h_stub_nm) <> semi
+     ,  returnResult
+     , rbrace
+     ]
+ )
+ where
+  -- tedious hack to let us deal with caller-cleans-up-stack
+  -- discipline that the C calling convention uses.
+  stubParamTypes
+     | cc == cCallConv = ptext SLIT("void*") : cParamTypes
+     | otherwise       = cParamTypes
+  stubArgs
+     | cc == cCallConv = ptext SLIT("_a0") : c_args
+     | otherwise       = c_args
+      
+  param_names = zipWith (\ i _ -> h_stub_nm <> text ('_':show i)) [1..] args
+  cParamTypes  = map (text.showPrimRepToUser.typePrimRep) args
+  (cResType, cResDecl) = 
+   case res of
+     Nothing -> (text "void", empty)
+     Just t  -> (text (showPrimRepToUser (typePrimRep t)),
+		 text "extern" <+> cResType <+> res_name <> semi)
+
+  pprCconv
+   | cc == cCallConv = empty
+   | otherwise	     = pprCallConv cc
+     
+  externDecls = 
+    vcat (zipWith mkExtern cParamTypes param_names) $$
+    cResDecl $$
+    text "extern void" <+> h_stub_nm <> text "();"
+
+  mkExtern ty nm = text "extern" <+> ty <+> nm <> semi
+
+  c_args = zipWith (\ _ n -> text ('a':show n)) args [0..] 
+
+  assignArgs p_nm c_arg = p_nm <+> equals <+> c_arg <> semi
+
+  returnResult = 
+    case res of
+      Nothing -> empty
+      Just _  -> text "return" <+> res_name <> semi
+
+  (res_name, res_ty) = 
+    case res of
+      Nothing -> (empty, empty)
+      Just t  -> (h_stub_nm <> text "_res", ppr (typePrimRep t))
+
+declVar :: SDoc -> SDoc -> SDoc
+declVar ty var = ty <+> var <> semi
+
+\end{code}
+
+When exporting
+
+   f :: Int -> Int -> Int -> IO Int
+
+we'll emit the following stuff into the .hc file 
+
+\begin{pseudocode}
+StgInt __f_param_1;
+StgInt __f_param_2;
+StgInt __f_param_3;
+StgInt __f_res;
+
+STGFUN(ds_f)
+{
+   FUNBEGIN;
+   RestoreAllStgRegs();
+   STK_CHK(LivenessReg,0/*A*/,(SIZE_IN_WORDS(StgInt) + 
+			       SIZE_IN_WORDS(StgInt) +
+			       SIZE_IN_WORDS(StgInt) + 1)/*B*/, 0, 0, 0/*prim*/, 0/*re-enter*/);
+   RetReg = (StgRetAddr) UNVEC(stopds_fDirectReturn,vtbl_stopds_f);
+   SpB  -= BREL(1);
+   *SpB  = (W_)__f_param_3;
+   SpB  -= BREL(1);
+   *SpB  = (W_)__f_param_2;
+   SpB  -= BREL(1);
+   *SpB  = (W_)__f_param_1;
+
+    SpB -= BREL(1);
+    *SpB = (W_) realWorldZh_closure;
+
+    Node = ds_f_helper_closure;
+    ENT_VIA_NODE();
+    InfoPtr=(D_)(INFO_PTR(Node));
+    JMP_(ENTRY_CODE(InfoPtr));
+    FUNEND;
+}
+
+STGFUN(stop_ds_fDirectReturn)
+{
+   FUNBEGIN;
+   __f_res=R1.i;   
+   SaveAllStgRegs();
+   RESUME(miniInterpretEnd);
+   FUNEND;
+}
+
+const W_ vtbl_stopds_f[] = {
+  (W_) stopds_fDirectReturn,
+  (W_) stopds_fDirectReturn,
+  (W_) stopds_fDirectReturn,
+  (W_) stopds_fDirectReturn,
+  (W_) stopds_fDirectReturn,
+  (W_) stopds_fDirectReturn,
+  (W_) stopds_fDirectReturn,
+  (W_) stopds_fDirectReturn
+};
+
+\end{pseudocode}
+
+and a C stub
+
+\begin{pseudocode}
+extern StgInt __f_param_1;
+extern StgInt __f_param_2;
+extern StgInt __f_param_3;
+extern StgInt __f_res;
+
+extern void ds_f();
+extern void miniInterpret(StgAddr);
+
+int
+f(a1,a2,a3)
+int a1;
+int a2;
+int a3;
+{
+ __f_param_1=a1;
+ __f_param_2=a2;
+ __f_param_3=a3;
+ miniInterpret((StgAddr)ds_f);
+ return (__f_res);
+}
+
+\end{pseudocode}
diff --git a/ghc/compiler/deSugar/DsMonad.lhs b/ghc/compiler/deSugar/DsMonad.lhs
index 19a4c33b40e6..bea0247f85be 100644
--- a/ghc/compiler/deSugar/DsMonad.lhs
+++ b/ghc/compiler/deSugar/DsMonad.lhs
@@ -7,13 +7,13 @@
 module DsMonad (
 	DsM,
 	initDs, returnDs, thenDs, andDs, mapDs, listDs,
-	mapAndUnzipDs, zipWithDs,
+	mapAndUnzipDs, zipWithDs, foldlDs,
 	uniqSMtoDsM,
 	newTyVarsDs, cloneTyVarsDs,
 	duplicateLocalDs, newSysLocalDs, newSysLocalsDs,
 	newFailLocalDs,
 	getSrcLocDs, putSrcLocDs,
-	getModuleAndGroupDs,
+	getModuleAndGroupDs, getUniqueDs,
 	extendEnvDs, lookupEnvDs, 
 	DsIdEnv,
 
@@ -39,6 +39,7 @@ import Type             ( Type )
 import TyVar		( cloneTyVar, TyVar )
 import UniqSupply	( splitUniqSupply, getUnique, getUniques,
 			  UniqSM, UniqSupply )
+import Unique		( Unique )			  
 import Util		( zipWithEqual, panic )
 
 infixr 9 `thenDs`
@@ -108,6 +109,13 @@ mapDs f (x:xs)
     mapDs f xs	`thenDs` \ rs ->
     returnDs (r:rs)
 
+foldlDs :: (a -> b -> DsM a) -> a -> [b] -> DsM a
+
+foldlDs k z []     = returnDs z
+foldlDs k z (x:xs) = k z x `thenDs` \ r ->
+		     foldlDs k r xs
+
+
 mapAndUnzipDs :: (a -> DsM (b, c)) -> [a] -> DsM ([b], [c])
 
 mapAndUnzipDs f []     = returnDs ([], [])
@@ -140,6 +148,11 @@ newSysLocalDs	    = newLocalDs SLIT("ds")
 newSysLocalsDs tys  = mapDs (newLocalDs SLIT("ds")) tys
 newFailLocalDs	    = newLocalDs SLIT("fail")
 
+getUniqueDs :: DsM Unique
+getUniqueDs us loc mod_and_grp env warns
+  = case (getUnique us) of { assigned_uniq ->
+    (assigned_uniq, warns) }
+
 duplicateLocalDs :: Id -> DsM Id
 duplicateLocalDs old_local us loc mod_and_grp env warns
   = case (getUnique us) of { assigned_uniq ->
diff --git a/ghc/compiler/deSugar/MatchLit.lhs b/ghc/compiler/deSugar/MatchLit.lhs
index a32f33e739f3..f9e39bb27f2d 100644
--- a/ghc/compiler/deSugar/MatchLit.lhs
+++ b/ghc/compiler/deSugar/MatchLit.lhs
@@ -20,7 +20,7 @@ import Id		( Id )
 import DsMonad
 import DsUtils
 
-import Literal		( mkMachInt, Literal(..) )
+import Literal		( mkMachInt_safe, Literal(..) )
 import PrimRep          ( PrimRep(IntRep) )
 import Maybes		( catMaybes )
 import Type		( Type, isUnpointedType )
@@ -68,7 +68,7 @@ matchLiterals all_vars@(var:vars) eqns_info@(EqnInfo n ctx (LitPat literal lit_t
       where
 	mk_core_lit :: Type -> HsLit -> Literal
 
-	mk_core_lit ty (HsIntPrim     i) = mkMachInt  i
+	mk_core_lit ty (HsIntPrim     i) = mkMachInt_safe i
 	mk_core_lit ty (HsCharPrim    c) = MachChar   c
 	mk_core_lit ty (HsStringPrim  s) = MachStr    s
 	mk_core_lit ty (HsFloatPrim   f) = MachFloat  f
-- 
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