Reorganisation of the source tree

Most of the other users of the fptools build system have migrated to
Cabal, and with the move to darcs we can now flatten the source tree
without losing history, so here goes.

The main change is that the ghc/ subdir is gone, and most of what it
contained is now at the top level.  The build system now makes no
pretense at being multi-project, it is just the GHC build system.

No doubt this will break many things, and there will be a period of
instability while we fix the dependencies.  A straightforward build
should work, but I haven't yet fixed binary/source distributions.
Changes to the Building Guide will follow, too.

1 files changed, 456 insertions, 0 deletions

diff --git a/compiler/deSugar/DsCCall.lhs b/compiler/deSugar/DsCCall.lhs
new file mode 100644
index 0000000000..3554197fb8
--- /dev/null
+++ b/compiler/deSugar/DsCCall.lhs
@@ -0,0 +1,456 @@
+%
+% (c) The AQUA Project, Glasgow University, 1994-1998
+%
+\section[DsCCall]{Desugaring C calls}
+
+\begin{code}
+module DsCCall 
+	( dsCCall
+	, mkFCall
+	, unboxArg
+	, boxResult
+	, resultWrapper
+	) where
+
+#include "HsVersions.h"
+
+
+import CoreSyn
+
+import DsMonad
+
+import CoreUtils	( exprType, coreAltType, mkCoerce2 )
+import Id		( Id, mkWildId )
+import MkId		( mkFCallId, realWorldPrimId, mkPrimOpId )
+import Maybes		( maybeToBool )
+import ForeignCall	( ForeignCall(..), CCallSpec(..), CCallTarget(..), Safety, 
+			  CCallConv(..), CLabelString )
+import DataCon		( splitProductType_maybe, dataConSourceArity, dataConWrapId )
+
+import TcType		( tcSplitTyConApp_maybe )
+import Type		( Type, isUnLiftedType, mkFunTys, mkFunTy,
+			  tyVarsOfType, mkForAllTys, mkTyConApp, 
+			  isPrimitiveType, splitTyConApp_maybe, 
+			  splitRecNewType_maybe, splitForAllTy_maybe,
+			  isUnboxedTupleType
+			)
+
+import PrimOp		( PrimOp(..) )
+import TysPrim		( realWorldStatePrimTy, intPrimTy,
+			  byteArrayPrimTyCon, mutableByteArrayPrimTyCon,
+			  addrPrimTy
+			)
+import TyCon		( TyCon, tyConDataCons, tyConName )
+import TysWiredIn	( unitDataConId,
+			  unboxedSingletonDataCon, unboxedPairDataCon,
+			  unboxedSingletonTyCon, unboxedPairTyCon,
+			  trueDataCon, falseDataCon, 
+			  trueDataConId, falseDataConId,
+			  listTyCon, charTyCon, boolTy, 
+			  tupleTyCon, tupleCon
+			)
+import BasicTypes       ( Boxity(..) )
+import Literal		( mkMachInt )
+import PrelNames	( Unique, hasKey, ioTyConKey, boolTyConKey, unitTyConKey,
+			  int8TyConKey, int16TyConKey, int32TyConKey,
+			  word8TyConKey, word16TyConKey, word32TyConKey
+			  -- dotnet interop
+			  , marshalStringName, unmarshalStringName
+			  , marshalObjectName, unmarshalObjectName
+			  , objectTyConName
+			)
+import VarSet		( varSetElems )
+import Constants	( wORD_SIZE)
+import Outputable
+
+#ifdef DEBUG
+import TypeRep
+#endif
+
+\end{code}
+
+Desugaring of @ccall@s consists of adding some state manipulation,
+unboxing any boxed primitive arguments and boxing the result if
+desired.
+
+The state stuff just consists of adding in
+@PrimIO (\ s -> case s of { S# s# -> ... })@ in an appropriate place.
+
+The unboxing is straightforward, as all information needed to unbox is
+available from the type.  For each boxed-primitive argument, we
+transform:
+\begin{verbatim}
+   _ccall_ foo [ r, t1, ... tm ] e1 ... em
+   |
+   |
+   V
+   case e1 of { T1# x1# ->
+   ...
+   case em of { Tm# xm# -> xm#
+   ccall# foo [ r, t1#, ... tm# ] x1# ... xm#
+   } ... }
+\end{verbatim}
+
+The reboxing of a @_ccall_@ result is a bit tricker: the types don't
+contain information about the state-pairing functions so we have to
+keep a list of \tr{(type, s-p-function)} pairs.  We transform as
+follows:
+\begin{verbatim}
+   ccall# foo [ r, t1#, ... tm# ] e1# ... em#
+   |
+   |
+   V
+   \ s# -> case (ccall# foo [ r, t1#, ... tm# ] s# e1# ... em#) of
+	  (StateAnd<r># result# state#) -> (R# result#, realWorld#)
+\end{verbatim}
+
+\begin{code}
+dsCCall :: CLabelString	-- C routine to invoke
+	-> [CoreExpr]	-- Arguments (desugared)
+	-> Safety	-- Safety of the call
+	-> Type		-- Type of the result: IO t
+	-> DsM CoreExpr
+
+dsCCall lbl args may_gc result_ty
+  = mapAndUnzipDs unboxArg args	       `thenDs` \ (unboxed_args, arg_wrappers) ->
+    boxResult id Nothing result_ty  `thenDs` \ (ccall_result_ty, res_wrapper) ->
+    newUnique			       `thenDs` \ uniq ->
+    let
+	target = StaticTarget lbl
+	the_fcall    = CCall (CCallSpec target CCallConv may_gc)
+ 	the_prim_app = mkFCall uniq the_fcall unboxed_args ccall_result_ty
+    in
+    returnDs (foldr ($) (res_wrapper the_prim_app) arg_wrappers)
+
+mkFCall :: Unique -> ForeignCall 
+	-> [CoreExpr] 	-- Args
+	-> Type 	-- Result type
+	-> CoreExpr
+-- Construct the ccall.  The only tricky bit is that the ccall Id should have
+-- no free vars, so if any of the arg tys do we must give it a polymorphic type.
+-- 	[I forget *why* it should have no free vars!]
+-- For example:
+--	mkCCall ... [s::StablePtr (a->b), x::Addr, c::Char]
+--
+-- Here we build a ccall thus
+--	(ccallid::(forall a b.  StablePtr (a -> b) -> Addr -> Char -> IO Addr))
+--			a b s x c
+mkFCall uniq the_fcall val_args res_ty
+  = mkApps (mkVarApps (Var the_fcall_id) tyvars) val_args
+  where
+    arg_tys = map exprType val_args
+    body_ty = (mkFunTys arg_tys res_ty)
+    tyvars  = varSetElems (tyVarsOfType body_ty)
+    ty 	    = mkForAllTys tyvars body_ty
+    the_fcall_id = mkFCallId uniq the_fcall ty
+\end{code}
+
+\begin{code}
+unboxArg :: CoreExpr			-- The supplied argument
+	 -> DsM (CoreExpr,		-- To pass as the actual argument
+		 CoreExpr -> CoreExpr	-- Wrapper to unbox the arg
+		)
+-- Example: if the arg is e::Int, unboxArg will return
+--	(x#::Int#, \W. case x of I# x# -> W)
+-- where W is a CoreExpr that probably mentions x#
+
+unboxArg arg
+  -- Primtive types: nothing to unbox
+  | isPrimitiveType arg_ty
+  = returnDs (arg, \body -> body)
+
+  -- Recursive newtypes
+  | Just rep_ty <- splitRecNewType_maybe arg_ty
+  = unboxArg (mkCoerce2 rep_ty arg_ty arg)
+      
+  -- Booleans
+  | Just (tc,_) <- splitTyConApp_maybe arg_ty, 
+    tc `hasKey` boolTyConKey
+  = newSysLocalDs intPrimTy		`thenDs` \ prim_arg ->
+    returnDs (Var prim_arg,
+	      \ body -> Case (Case arg (mkWildId arg_ty) intPrimTy
+  		                       [(DataAlt falseDataCon,[],mkIntLit 0),
+	                                (DataAlt trueDataCon, [],mkIntLit 1)])
+					-- In increasing tag order!
+                             prim_arg
+                             (exprType body) 
+			     [(DEFAULT,[],body)])
+
+  -- Data types with a single constructor, which has a single, primitive-typed arg
+  -- This deals with Int, Float etc; also Ptr, ForeignPtr
+  | is_product_type && data_con_arity == 1 
+  = ASSERT2(isUnLiftedType data_con_arg_ty1, pprType arg_ty)
+			-- Typechecker ensures this
+    newSysLocalDs arg_ty		`thenDs` \ case_bndr ->
+    newSysLocalDs data_con_arg_ty1	`thenDs` \ prim_arg ->
+    returnDs (Var prim_arg,
+	      \ body -> Case arg case_bndr (exprType body) [(DataAlt data_con,[prim_arg],body)]
+    )
+
+  -- Byte-arrays, both mutable and otherwise; hack warning
+  -- We're looking for values of type ByteArray, MutableByteArray
+  --	data ByteArray          ix = ByteArray        ix ix ByteArray#
+  --	data MutableByteArray s ix = MutableByteArray ix ix (MutableByteArray# s)
+  | is_product_type &&
+    data_con_arity == 3 &&
+    maybeToBool maybe_arg3_tycon &&
+    (arg3_tycon ==  byteArrayPrimTyCon ||
+     arg3_tycon ==  mutableByteArrayPrimTyCon)
+  = newSysLocalDs arg_ty		`thenDs` \ case_bndr ->
+    newSysLocalsDs data_con_arg_tys	`thenDs` \ vars@[l_var, r_var, arr_cts_var] ->
+    returnDs (Var arr_cts_var,
+	      \ body -> Case arg case_bndr (exprType body) [(DataAlt data_con,vars,body)]
+
+    )
+
+  | Just (tc, [arg_ty]) <- splitTyConApp_maybe arg_ty,
+    tc == listTyCon,
+    Just (cc,[]) <- splitTyConApp_maybe arg_ty,
+    cc == charTyCon
+    -- String; dotnet only
+  = dsLookupGlobalId marshalStringName `thenDs` \ unpack_id ->
+    newSysLocalDs addrPrimTy	       `thenDs` \ prim_string ->
+    returnDs (Var prim_string,
+    	      \ body ->
+	        let
+		 io_ty = exprType body
+		 (Just (_,[io_arg])) = tcSplitTyConApp_maybe io_ty
+		in
+	      	mkApps (Var unpack_id)
+		       [ Type io_arg
+		       , arg
+		       , Lam prim_string body
+		       ])
+  | Just (tc, [arg_ty]) <- splitTyConApp_maybe arg_ty,
+    tyConName tc == objectTyConName
+    -- Object; dotnet only
+  = dsLookupGlobalId marshalObjectName `thenDs` \ unpack_id ->
+    newSysLocalDs addrPrimTy	       `thenDs` \ prim_obj  ->
+    returnDs (Var prim_obj,
+    	      \ body ->
+	        let
+		 io_ty = exprType body
+		 (Just (_,[io_arg])) = tcSplitTyConApp_maybe io_ty
+		in
+	      	mkApps (Var unpack_id)
+		       [ Type io_arg
+		       , arg
+		       , Lam prim_obj body
+		       ])
+
+  | otherwise
+  = getSrcSpanDs `thenDs` \ l ->
+    pprPanic "unboxArg: " (ppr l <+> ppr arg_ty)
+  where
+    arg_ty					= exprType arg
+    maybe_product_type 			   	= splitProductType_maybe arg_ty
+    is_product_type			   	= maybeToBool maybe_product_type
+    Just (_, _, data_con, data_con_arg_tys)	= maybe_product_type
+    data_con_arity				= dataConSourceArity data_con
+    (data_con_arg_ty1 : _)			= data_con_arg_tys
+
+    (_ : _ : data_con_arg_ty3 : _) = data_con_arg_tys
+    maybe_arg3_tycon    	   = splitTyConApp_maybe data_con_arg_ty3
+    Just (arg3_tycon,_)		   = maybe_arg3_tycon
+\end{code}
+
+
+\begin{code}
+boxResult :: ((Maybe Type, CoreExpr -> CoreExpr) -> (Maybe Type, CoreExpr -> CoreExpr))
+	  -> Maybe Id
+	  -> Type
+	  -> DsM (Type, CoreExpr -> CoreExpr)
+
+-- Takes the result of the user-level ccall: 
+--	either (IO t), 
+--	or maybe just t for an side-effect-free call
+-- Returns a wrapper for the primitive ccall itself, along with the
+-- type of the result of the primitive ccall.  This result type
+-- will be of the form  
+--	State# RealWorld -> (# State# RealWorld, t' #)
+-- where t' is the unwrapped form of t.  If t is simply (), then
+-- the result type will be 
+--	State# RealWorld -> (# State# RealWorld #)
+
+boxResult augment mbTopCon result_ty
+  = case tcSplitTyConApp_maybe result_ty of
+	-- This split absolutely has to be a tcSplit, because we must
+	-- see the IO type; and it's a newtype which is transparent to splitTyConApp.
+
+	-- The result is IO t, so wrap the result in an IO constructor
+	Just (io_tycon, [io_res_ty]) | io_tycon `hasKey` ioTyConKey
+		-> resultWrapper io_res_ty             `thenDs` \ res ->
+		   let aug_res          = augment res
+		       extra_result_tys =
+		         case aug_res of
+			   (Just ty,_) 
+			     | isUnboxedTupleType ty ->
+			        let (Just (_, ls)) = splitTyConApp_maybe ty in tail ls
+			   _ -> []
+	           in
+		   mk_alt (return_result extra_result_tys) aug_res 
+		   					`thenDs` \ (ccall_res_ty, the_alt) ->
+		   newSysLocalDs  realWorldStatePrimTy  `thenDs` \ state_id ->
+		   let
+			io_data_con = head (tyConDataCons io_tycon)
+			toIOCon = 
+			  case mbTopCon of
+			    Nothing -> dataConWrapId io_data_con
+			    Just x  -> x
+			wrap = \ the_call -> 
+				 mkApps (Var toIOCon)
+					   [ Type io_res_ty, 
+					     Lam state_id $
+					      Case (App the_call (Var state_id))
+						   (mkWildId ccall_res_ty)
+                                                   (coreAltType the_alt) 
+						   [the_alt]
+					   ]
+		   in
+		   returnDs (realWorldStatePrimTy `mkFunTy` ccall_res_ty, wrap)
+		where
+		   return_result ts state anss 
+		     = mkConApp (tupleCon Unboxed (2 + length ts))
+			        (Type realWorldStatePrimTy : Type io_res_ty : map Type ts ++
+			         state : anss) 
+	-- It isn't, so do unsafePerformIO
+	-- It's not conveniently available, so we inline it
+	other -> resultWrapper result_ty            `thenDs` \ res ->
+	         mk_alt return_result (augment res) `thenDs` \ (ccall_res_ty, the_alt) ->
+		 let
+		    wrap = \ the_call -> Case (App the_call (Var realWorldPrimId)) 
+					      (mkWildId ccall_res_ty)
+                                              (coreAltType the_alt)
+					      [the_alt]
+		 in
+		 returnDs (realWorldStatePrimTy `mkFunTy` ccall_res_ty, wrap)
+	      where
+		 return_result state [ans] = ans
+		 return_result _ _ = panic "return_result: expected single result"
+  where
+    mk_alt return_result (Nothing, wrap_result)
+	= 	-- The ccall returns ()
+	  newSysLocalDs realWorldStatePrimTy	`thenDs` \ state_id ->
+	  let
+		the_rhs = return_result (Var state_id) 
+					[wrap_result (panic "boxResult")]
+
+		ccall_res_ty = mkTyConApp unboxedSingletonTyCon [realWorldStatePrimTy]
+		the_alt      = (DataAlt unboxedSingletonDataCon, [state_id], the_rhs)
+	  in
+	  returnDs (ccall_res_ty, the_alt)
+
+    mk_alt return_result (Just prim_res_ty, wrap_result)
+    		-- The ccall returns a non-() value
+        | isUnboxedTupleType prim_res_ty
+        = let
+		Just (_, ls) = splitTyConApp_maybe prim_res_ty
+		arity = 1 + length ls
+	  in
+	  mappM newSysLocalDs ls 		`thenDs` \ args_ids@(result_id:as) ->
+	  newSysLocalDs realWorldStatePrimTy	`thenDs` \ state_id ->
+	  let
+		the_rhs = return_result (Var state_id) 
+					(wrap_result (Var result_id) : map Var as)
+		ccall_res_ty = mkTyConApp (tupleTyCon Unboxed arity)
+					  (realWorldStatePrimTy : ls)
+		the_alt	     = ( DataAlt (tupleCon Unboxed arity)
+			       , (state_id : args_ids)
+			       , the_rhs
+			       )
+	  in
+	  returnDs (ccall_res_ty, the_alt)
+	| otherwise
+	= newSysLocalDs prim_res_ty 		`thenDs` \ result_id ->
+	  newSysLocalDs realWorldStatePrimTy	`thenDs` \ state_id ->
+	  let
+		the_rhs = return_result (Var state_id) 
+					[wrap_result (Var result_id)]
+
+		ccall_res_ty = mkTyConApp unboxedPairTyCon [realWorldStatePrimTy, prim_res_ty]
+		the_alt	     = (DataAlt unboxedPairDataCon, [state_id, result_id], the_rhs)
+	  in
+	  returnDs (ccall_res_ty, the_alt)
+
+
+resultWrapper :: Type
+   	      -> DsM (Maybe Type,		-- Type of the expected result, if any
+		      CoreExpr -> CoreExpr)	-- Wrapper for the result 
+resultWrapper result_ty
+  -- Base case 1: primitive types
+  | isPrimitiveType result_ty
+  = returnDs (Just result_ty, \e -> e)
+
+  -- Base case 2: the unit type ()
+  | Just (tc,_) <- maybe_tc_app, tc `hasKey` unitTyConKey
+  = returnDs (Nothing, \e -> Var unitDataConId)
+
+  -- Base case 3: the boolean type
+  | Just (tc,_) <- maybe_tc_app, tc `hasKey` boolTyConKey
+  = returnDs
+     (Just intPrimTy, \e -> Case e (mkWildId intPrimTy)
+                                   boolTy
+	                           [(DEFAULT             ,[],Var trueDataConId ),
+				    (LitAlt (mkMachInt 0),[],Var falseDataConId)])
+
+  -- Recursive newtypes
+  | Just rep_ty <- splitRecNewType_maybe result_ty
+  = resultWrapper rep_ty `thenDs` \ (maybe_ty, wrapper) ->
+    returnDs (maybe_ty, \e -> mkCoerce2 result_ty rep_ty (wrapper e))
+
+  -- The type might contain foralls (eg. for dummy type arguments,
+  -- referring to 'Ptr a' is legal).
+  | Just (tyvar, rest) <- splitForAllTy_maybe result_ty
+  = resultWrapper rest `thenDs` \ (maybe_ty, wrapper) ->
+    returnDs (maybe_ty, \e -> Lam tyvar (wrapper e))
+
+  -- Data types with a single constructor, which has a single arg
+  -- This includes types like Ptr and ForeignPtr
+  | Just (tycon, tycon_arg_tys, data_con, data_con_arg_tys) <- splitProductType_maybe result_ty,
+    dataConSourceArity data_con == 1
+  = let
+	(unwrapped_res_ty : _) = data_con_arg_tys
+	narrow_wrapper         = maybeNarrow tycon
+    in
+    resultWrapper unwrapped_res_ty `thenDs` \ (maybe_ty, wrapper) ->
+    returnDs
+      (maybe_ty, \e -> mkApps (Var (dataConWrapId data_con)) 
+			      (map Type tycon_arg_tys ++ [wrapper (narrow_wrapper e)]))
+
+    -- Strings; 'dotnet' only.
+  | Just (tc, [arg_ty]) <- maybe_tc_app,               tc == listTyCon,
+    Just (cc,[])        <- splitTyConApp_maybe arg_ty, cc == charTyCon
+  = dsLookupGlobalId unmarshalStringName	`thenDs` \ pack_id ->
+    returnDs (Just addrPrimTy,
+    	      \ e -> App (Var pack_id) e)
+
+    -- Objects; 'dotnet' only.
+  | Just (tc, [arg_ty]) <- maybe_tc_app, 
+    tyConName tc == objectTyConName
+  = dsLookupGlobalId unmarshalObjectName	`thenDs` \ pack_id ->
+    returnDs (Just addrPrimTy,
+    	      \ e -> App (Var pack_id) e)
+
+  | otherwise
+  = pprPanic "resultWrapper" (ppr result_ty)
+  where
+    maybe_tc_app = splitTyConApp_maybe result_ty
+
+-- When the result of a foreign call is smaller than the word size, we
+-- need to sign- or zero-extend the result up to the word size.  The C
+-- standard appears to say that this is the responsibility of the
+-- caller, not the callee.
+
+maybeNarrow :: TyCon -> (CoreExpr -> CoreExpr)
+maybeNarrow tycon
+  | tycon `hasKey` int8TyConKey   = \e -> App (Var (mkPrimOpId Narrow8IntOp)) e
+  | tycon `hasKey` int16TyConKey  = \e -> App (Var (mkPrimOpId Narrow16IntOp)) e
+  | tycon `hasKey` int32TyConKey
+	 && wORD_SIZE > 4         = \e -> App (Var (mkPrimOpId Narrow32IntOp)) e
+
+  | tycon `hasKey` word8TyConKey  = \e -> App (Var (mkPrimOpId Narrow8WordOp)) e
+  | tycon `hasKey` word16TyConKey = \e -> App (Var (mkPrimOpId Narrow16WordOp)) e
+  | tycon `hasKey` word32TyConKey
+	 && wORD_SIZE > 4         = \e -> App (Var (mkPrimOpId Narrow32WordOp)) e
+  | otherwise			  = id
+\end{code}