2 % (c) The GRASP/AQUA Project, Glasgow University, 1993-2000
4 \section{Generate Java}
6 Name mangling for Java.
9 Haskell has a number of namespaces. The Java translator uses
10 the standard Haskell mangles (see OccName.lhs), and some extra
13 All names are hidden inside packages.
16 - becomes a first level java package.
17 - can not clash with java, because haskell modules are upper case,
18 java default packages are lower case.
21 - these turn into classes
22 - java keywords (eg. private) have the suffix "zdk" ($k) added.
25 - These have a base class, so need to appear in the
26 same name space as other object. for example data Foo = Foo
27 - We add a postfix to types: "zdc" ($c)
28 - Types are upper case, so never clash with keywords
31 - There are tWO classes for each Constructor
32 (1) - Class with the payload extends the relevent datatype baseclass.
33 - This class has the prefix zdw ($w)
34 (2) - Constructor *wrapper* just use their own name.
35 - Constructors are upper case, so never clash with keywords
36 - So Foo would become 2 classes.
37 * Foo -- the constructor wrapper
38 * zdwFoo -- the worker, with the payload
42 $k for keyword nameclash avoidance.
45 module JavaGen( javaGen ) where
49 import Literal ( Literal(..) )
50 import Id ( Id, isDataConId_maybe, isId, idName, isDeadBinder, idPrimRep
52 import Name ( NamedThing(..), getOccString, isGlobalName, isLocalName
54 import PrimRep ( PrimRep(..) )
55 import DataCon ( DataCon, dataConRepArity, dataConRepArgTys, dataConId )
57 import qualified CoreSyn
58 import CoreSyn ( CoreBind, CoreExpr, CoreAlt, CoreBndr,
59 Bind(..), AltCon(..), collectBinders, isValArg
61 import TysWiredIn ( boolTy, trueDataCon, falseDataCon )
62 import qualified CoreUtils
63 import Module ( Module, moduleString )
64 import TyCon ( TyCon, isDataTyCon, tyConDataCons )
70 #include "HsVersions.h"
76 javaGen :: Module -> [Module] -> [TyCon] -> [CoreBind] -> CompilationUnit
78 javaGen mod import_mods tycons binds
79 = liftCompilationUnit package
81 decls = [Import "haskell.runtime.*"] ++
82 [Import (moduleString mod) | mod <- import_mods] ++
83 concat (map javaTyCon (filter isDataTyCon tycons)) ++
84 concat (map javaTopBind binds)
85 package = Package (moduleString mod) decls
89 %************************************************************************
91 \subsection{Type declarations}
93 %************************************************************************
96 javaTyCon :: TyCon -> [Decl]
97 -- public class List {}
99 -- public class $wCons extends List {
100 -- Object f1; Object f2
102 -- public class $wNil extends List {}
105 = tycon_jclass : concat (map constr_class constrs)
107 constrs = tyConDataCons tycon
108 tycon_jclass_jname = javaTyConTypeName tycon ++ "zdc"
109 tycon_jclass = Class [Public] (shortName tycon_jclass_jname) [] [] []
111 constr_class data_con
112 = [ Class [Public] constr_jname [tycon_jclass_jname] []
113 (field_decls ++ [cons_meth,debug_meth])
116 constr_jname = shortName (javaConstrWkrName data_con)
118 field_names = constrToFields data_con
119 field_decls = [ Field [Public] n Nothing
123 cons_meth = mkCons constr_jname field_names
125 debug_meth = Method [Public] (Name "toString" stringType)
128 ( [ Declaration (Field [] txt Nothing) ]
133 getOccString data_con ++
142 (Op (Var n) "+" litSp)
147 ++ [ Return (Op (Var txt)
155 txt = Name "__txt" stringType
158 -- This checks to see the type is reasonable to call new with.
159 -- primitives might use a static method later.
160 mkNew :: Type -> [Expr] -> Expr
161 mkNew t@(PrimType primType) _ = error "new primitive -- fix it???"
162 mkNew t@(Type _) es = New t es Nothing
163 mkNew _ _ = error "new with strange arguments"
165 constrToFields :: DataCon -> [Name]
166 constrToFields cons =
168 | (i,t) <- zip [1..] (map primRepToType
169 (map Type.typePrimRep
170 (dataConRepArgTys cons)
175 mkCons :: TypeName -> [Name] -> Decl
176 mkCons name args = Constructor [Public] name
177 [ Parameter [] n | n <- args ]
178 [ ExprStatement (Assign
184 mkStr :: String -> Expr
185 mkStr str = Literal (StringLit str)
188 %************************************************************************
190 \subsection{Bindings}
192 %************************************************************************
195 javaTopBind :: CoreBind -> [Decl]
196 javaTopBind (NonRec bndr rhs) = [java_top_bind bndr rhs]
197 javaTopBind (Rec prs) = [java_top_bind bndr rhs | (bndr,rhs) <- prs]
199 java_top_bind :: Id -> CoreExpr -> Decl
200 -- public class f implements Code {
201 -- public Object ENTER() { ...translation of rhs... }
203 java_top_bind bndr rhs
204 = Class [Public] (shortName (javaIdTypeName bndr))
205 [] [codeName] [enter_meth]
207 enter_meth = Method [Public]
211 (javaExpr vmRETURN rhs)
214 %************************************************************************
216 \subsection{Expressions}
218 %************************************************************************
221 javaVar :: Id -> Expr
222 javaVar v | isGlobalName (idName v) = mkNew (javaIdType v) []
223 | otherwise = Var (javaName v)
225 javaLit :: Literal.Literal -> Expr
226 javaLit (MachInt i) = Literal (IntLit (fromInteger i))
227 javaLit (MachChar c) = Literal (CharLit c)
228 javaLit (MachStr fs) = Literal (StringLit str)
230 str = concatMap renderString (_UNPK_ fs) ++ "\\000"
231 -- This should really handle all the chars 0..31.
232 renderString '\NUL' = "\\000"
233 renderString other = [other]
235 javaLit other = pprPanic "javaLit" (ppr other)
237 -- Pass in the 'shape' of the result.
238 javaExpr :: (Expr -> Statement) -> CoreExpr -> [Statement]
239 -- Generate code to apply the value of
240 -- the expression to the arguments aleady on the stack
241 javaExpr r (CoreSyn.Var v) = [r (javaVar v)]
242 javaExpr r (CoreSyn.Lit l) = [r (javaLit l)]
243 javaExpr r (CoreSyn.App f a) = javaApp r f [a]
244 javaExpr r e@(CoreSyn.Lam _ _) = javaLam r (collectBinders e)
245 javaExpr r (CoreSyn.Case e x alts) = javaCase r e x alts
246 javaExpr r (CoreSyn.Let bind body) = javaBind bind ++ javaExpr r body
247 javaExpr r (CoreSyn.Note _ e) = javaExpr r e
249 javaCase :: (Expr -> Statement) -> CoreExpr -> Id -> [CoreAlt] -> [Statement]
250 -- case e of x { Nil -> r1
253 -- final Object x = VM.WHNF(...code for e...)
254 -- else if x instance_of Nil {
255 -- ...translation of r1...
256 -- } else if x instance_of Cons {
257 -- final Object p = ((Cons) x).f1
258 -- final Object q = ((Cons) x).f2
259 -- ...translation of r2...
260 -- } else throw java.lang.Exception
262 -- This first special case happens a lot, typically
263 -- during dictionary deconstruction.
264 -- We need to access at least *one* field, to check to see
265 -- if we have correct constructor.
266 -- If we've got the wrong one, this is _|_, and the
267 -- casting will catch this with an exception.
269 javaCase r e x [(DataAlt d,bs,rhs)] | length bs > 0
270 = java_expr PushExpr e ++
271 [ var [Final] (javaName x)
272 (whnf primRep (vmPOP (primRepToType primRep))) ] ++
276 primRep = idPrimRep x
277 whnf PtrRep = vmWHNF -- needs evaluation
278 whnf _ = id -- anything else does notg
280 bind_args d bs = [var [Final] (javaName b)
281 (Access (Cast (javaConstrWkrType d) (javaVar x)
284 | (b,f) <- filter isId bs `zip` (constrToFields d)
285 , not (isDeadBinder b)
289 | isIfThenElse && isPrimCmp =
290 javaIfThenElse r (fromJust maybePrim) tExpr fExpr
292 java_expr PushExpr e ++
293 [ var [Final] (javaName x)
294 (whnf primRep (vmPOP (primRepToType primRep)))
295 , mkIfThenElse (map mk_alt alts)
298 isIfThenElse = CoreUtils.exprType e == boolTy
299 -- also need to check that x is not free in
300 -- any of the branches.
301 maybePrim = findCmpPrim e []
302 isPrimCmp = isJust maybePrim
303 tExpr = matches trueDataCon alts
304 fExpr = matches falseDataCon alts
306 matches con [] = error "no match for true or false branch of if/then/else"
307 matches con ((DataAlt d,[],rhs):rest) | con == d = rhs
308 matches con ((DEFAULT,[],rhs):_) = rhs
309 matches con (other:rest) = matches con rest
311 primRep = idPrimRep x
312 whnf PtrRep = vmWHNF -- needs evaluation
315 mk_alt (DEFAULT, [], rhs) = (true, Block (javaExpr r rhs))
316 mk_alt (DataAlt d, bs, rhs) = (instanceOf x d, Block (bind_args d bs ++ javaExpr r rhs))
317 mk_alt alt@(LitAlt lit, [], rhs)
318 = (eqLit lit , Block (javaExpr r rhs))
319 mk_alt alt@(LitAlt _, _, _) = pprPanic "mk_alt" (ppr alt)
322 eqLit (MachInt n) = Op (Literal (IntLit n))
326 eqLit (MachChar n) = Op (Literal (CharLit n))
329 eqLit other = pprPanic "eqLit" (ppr other)
331 bind_args d bs = [var [Final] (javaName b)
332 (Access (Cast (javaConstrWkrType d) (javaVar x)
335 | (b,f) <- filter isId bs `zip` (constrToFields d)
336 , not (isDeadBinder b)
340 mkIfThenElse [(Var (Name "true" _),code)] = code
341 mkIfThenElse other = IfThenElse other
343 (Raise excName [Literal (StringLit "case failure")])
347 javaIfThenElse r cmp tExpr fExpr
349 - Now what we need to do is generate code for the if/then/else.
350 - [all arguments are already check for simpleness (Var or Lit).]
352 - if (<prim> arg1 arg2 arg3 ...) {
358 = [IfThenElse [(cmp,j_tExpr)] (Just j_fExpr)]
360 j_tExpr, j_fExpr :: Statement
361 j_tExpr = Block (javaExpr r tExpr)
362 j_fExpr = Block (javaExpr r fExpr)
364 javaBind (NonRec x rhs)
368 final Object x = new Thunk( new Code() { ...code for rhs_x... } )
371 = java_expr (SetVar name) rhs
373 name = case coreTypeToType rhs of
374 ty@(PrimType _) -> javaName x `withType` ty
375 _ -> javaName x `withType` codeType
378 {- rec { x = ...rhs_x...; y = ...rhs_y... }
380 class x implements Code {
382 public Object ENTER() { ...code for rhs_x...}
386 final x x_inst = new x();
389 final Thunk x = new Thunk( x_inst );
396 = (map mk_class prs) ++ (map mk_inst prs) ++
397 (map mk_thunk prs) ++ concat (map mk_knot prs)
399 mk_class (b,r) = Declaration (Class [] class_name [] [codeName] stmts)
401 class_name = javaIdTypeName b
402 stmts = [Field [] (javaName b `withType` codeType) Nothing | (b,_) <- prs] ++
403 [Method [Public] enterName [vmArg] [excName] (javaExpr vmRETURN r)]
405 mk_inst (b,r) = var [Final] name (mkNew ty [])
407 name@(Name _ ty) = javaInstName b
409 mk_thunk (b,r) = var [Final] (javaName b `withType` codeType)
410 (mkNew thunkType [Var (javaInstName b)])
412 mk_knot (b,_) = [ ExprStatement (Assign lhs rhs)
414 let lhs = Access (Var (javaInstName b)) (javaName b'),
415 let rhs = Var (javaName b')
418 javaLam :: (Expr -> Statement) -> ([CoreBndr], CoreExpr) -> [Statement]
419 javaLam r (bndrs, body)
420 | null val_bndrs = javaExpr r body
422 = vmCOLLECT (length val_bndrs) this
423 ++ [var [Final] n (vmPOP t) | n@(Name _ t) <- val_bndrs]
426 val_bndrs = map javaName (filter isId bndrs)
428 javaApp :: (Expr -> Statement) -> CoreExpr -> [CoreExpr] -> [Statement]
429 javaApp r (CoreSyn.App f a) as
430 | isValArg a = javaApp r f (a:as)
431 | otherwise = javaApp r f as
432 javaApp r (CoreSyn.Var f) as
433 = case isDataConId_maybe f of {
434 Just dc | length as == dataConRepArity dc
435 -- NOTE: Saturated constructors never returning a primitive at this point
437 -- We push the arguments backwards, because we are using
438 -- the (ugly) semantics of the order of evaluation of arguments,
439 -- to avoid making up local names. Oh to have a namesupply...
441 -> javaArgs (reverse as) ++
442 [r (New (javaIdType f)
450 vmCOLLECT (dataConRepArity dc) this ++
453 [ vmPOP ty | (Name _ ty) <- constrToFields dc ]
457 in javaArgs (reverse as) ++ [r (newCode stmts)]
458 ; other -> java_apply r (CoreSyn.Var f) as
461 javaApp r f as = java_apply r f as
463 -- This means, given a expression an a list of arguments,
464 -- generate code for "pushing the arguments on the stack,
465 -- and the executing the expression."
467 java_apply :: (Expr -> Statement) -> CoreExpr -> [CoreExpr] -> [Statement]
468 java_apply r f as = javaArgs as ++ javaExpr r f
470 -- This generates statements that have the net effect
471 -- of pushing values (perhaps thunks) onto the stack.
473 javaArgs :: [CoreExpr] -> [Statement]
474 javaArgs args = concat [ java_expr PushExpr a | a <- args, isValArg a]
476 javaPops :: [CoreExpr] -> [Expr]
477 javaPops args = [ vmPOP (primRepToType (Type.typePrimRep (CoreUtils.exprType a)))
483 -- The result is a list of statments that have the effect of
484 -- pushing onto the stack (via one of the VM.PUSH* commands)
485 -- the argument, (or returning, or setting a variable)
488 {- This is mixing two things.
489 (1) Optimizations for things like primitives, whnf calls, etc.
490 (2) If something needs a thunk constructor round it.
491 - Seperate them at some point!
493 data ExprRetStyle = SetVar Name | PushExpr | ReturnExpr
495 java_expr :: ExprRetStyle -> CoreExpr -> [Statement]
496 java_expr _ (CoreSyn.Type t) = pprPanic "java_expr" (ppr t)
498 | isPrimCall = [push (fromJust maybePrim)]
499 -- This is a shortcut,
500 -- basic names and literals do not need a code block
501 -- to compute the value.
502 | isPrim primty && CoreUtils.exprIsTrivial e = javaExpr push e
504 let expr = javaExpr vmRETURN e
505 code = access (vmWHNF (newCode expr)) (primRepToType primty)
508 let expr = javaExpr vmRETURN e
510 code' = if CoreUtils.exprIsValue e
511 || CoreUtils.exprIsTrivial e
517 maybePrim = findFnPrim e []
518 isPrimCall = isJust maybePrim
521 SetVar name -> var [Final] name e
523 ReturnExpr -> vmRETURN e
524 corety = CoreUtils.exprType e
525 primty = Type.typePrimRep corety
526 isPrim PtrRep = False -- only this needs updated
529 coreTypeToType = primRepToType . Type.typePrimRep . CoreUtils.exprType
531 renameForKeywords :: (NamedThing name) => name -> String
532 renameForKeywords name
533 | str `elem` keywords = "zdk" ++ str
536 str = getOccString name
553 %************************************************************************
555 \subsection{Helper functions}
557 %************************************************************************
560 true, this,javaNull :: Expr
562 true = Var (Name "true" (PrimType PrimBoolean))
563 javaNull = Var (Name "null" objectType)
565 vmCOLLECT :: Int -> Expr -> [Statement]
567 vmCOLLECT n e = [ExprStatement
568 (Call varVM collectName
569 [ Literal (IntLit (toInteger n))
575 vmPOP :: Type -> Expr
576 vmPOP ty = Call varVM (Name ("POP" ++ suffix ty) ty) []
578 vmPUSH :: Expr -> Statement
579 vmPUSH e = ExprStatement
580 (Call varVM (Name ("PUSH" ++ suffix (exprType e)) void) [e])
582 vmRETURN :: Expr -> Statement
583 vmRETURN e = Return (
585 PrimType _ -> Call varVM (Name ("RETURN" ++ suffix ty)
592 var :: [Modifier] -> Name -> Expr -> Statement
593 var ms field_name@(Name _ ty) value
594 | exprType value == ty = Declaration (Field ms field_name (Just value))
595 | otherwise = var ms field_name (Cast ty value)
597 vmWHNF :: Expr -> Expr
598 vmWHNF e = Call varVM whnfName [e]
600 suffix :: Type -> String
601 suffix (PrimType t) = primName t
604 primName :: PrimType -> String
605 primName PrimInt = "int"
606 primName PrimChar = "char"
607 primName PrimByte = "byte"
608 primName PrimBoolean = "boolean"
609 primName _ = error "unsupported primitive"
614 instanceOf :: Id -> DataCon -> Expr
615 instanceOf x data_con
616 = InstanceOf (Var (javaName x)) (javaConstrWkrType data_con)
618 newCode :: [Statement] -> Expr
619 newCode [Return e] = e
620 newCode stmts = New codeType [] (Just [Method [Public] enterName [vmArg] [excName] stmts])
622 newThunk :: Expr -> Expr
623 newThunk e = New thunkType [e] Nothing
626 vmArg = Parameter [Final] vmName
628 -- This is called with boolean compares, checking
629 -- to see if we can do an obvious shortcut.
630 -- If there is, we return a (GOO) expression for doing this,
632 -- So if, we have case (#< x y) of { True -> e1; False -> e2 },
633 -- we will call findCmpFn with (#< x y), this return Just (Op x "<" y)
635 findCmpPrim :: CoreExpr -> [Expr] -> Maybe Expr
636 findCmpPrim (CoreSyn.App f a) as =
638 CoreSyn.Var v -> findCmpPrim f (javaVar v:as)
639 CoreSyn.Lit l -> findCmpPrim f (javaLit l:as)
641 findCmpPrim (CoreSyn.Var p) as =
642 case isPrimOpId_maybe p of
643 Just prim -> find_cmp_prim prim as
645 findCmpPrim _ as = Nothing
647 find_cmp_prim cmpPrim args@[a,b] =
657 fn op = Just (Op a op b)
658 find_cmp_prim _ _ = Nothing
660 findFnPrim :: CoreExpr -> [Expr] -> Maybe Expr
661 findFnPrim (CoreSyn.App f a) as =
663 CoreSyn.Var v -> findFnPrim f (javaVar v:as)
664 CoreSyn.Lit l -> findFnPrim f (javaLit l:as)
666 findFnPrim (CoreSyn.Var p) as =
667 case isPrimOpId_maybe p of
668 Just prim -> find_fn_prim prim as
670 findFnPrim _ as = Nothing
672 find_fn_prim cmpPrim args@[a,b] =
679 fn op = Just (Op a op b)
680 find_fn_prim _ _ = Nothing
683 %************************************************************************
685 \subsection{Haskell to Java Types}
687 %************************************************************************
690 exprType (Var (Name _ t)) = t
691 exprType (Literal lit) = litType lit
692 exprType (Cast t _) = t
693 exprType (New t _ _) = t
694 exprType (Call _ (Name _ t) _) = t
695 exprType (Access _ (Name _ t)) = t
696 exprType (Raise t _) = error "do not know the type of raise!"
697 exprType (Op _ op _) | op `elem` ["==","/=","<","<=","=>",">"]
698 = PrimType PrimBoolean
699 exprType (Op x op _) | op `elem` ["+","-","*"]
701 exprType expr = error ("can't figure out an expression type: " ++ show expr)
703 litType (IntLit i) = PrimType PrimInt
704 litType (CharLit i) = PrimType PrimChar
705 litType (StringLit i) = stringType -- later, might use char array?
708 %************************************************************************
710 \subsection{Name mangling}
712 %************************************************************************
715 codeName, excName, thunkName :: TypeName
716 codeName = "haskell.runtime.Code"
717 thunkName = "haskell.runtime.Thunk"
718 excName = "java.lang.Exception"
720 enterName, vmName,thisName,collectName, whnfName :: Name
721 enterName = Name "ENTER" objectType
722 vmName = Name "VM" vmType
723 thisName = Name "this" (Type "<this>")
724 collectName = Name "COLLECT" void
725 whnfName = Name "WHNF" objectType
727 fieldName :: Int -> Type -> Name -- Names for fields of a constructor
728 fieldName n ty = Name ("f" ++ show n) ty
730 withType :: Name -> Type -> Name
731 withType (Name n _) t = Name n t
733 -- This maps (local only) names Ids to Names,
734 -- using the same string as the Id.
735 javaName :: Id -> Name
737 | isGlobalName (idName n) = error "useing javaName on global"
738 | otherwise = Name (getOccString n)
739 (primRepToType (idPrimRep n))
741 -- TypeName's are almost always global. This would typically return something
742 -- like Test.foo or Test.Foozdc or PrelBase.foldr.
743 -- Local might use locally bound types, (which do not have '.' in them).
745 javaIdTypeName :: Id -> TypeName
747 | isLocalName n' = renameForKeywords n'
748 | otherwise = moduleString (nameModule n') ++ "." ++ renameForKeywords n'
752 -- There is no such thing as a local type constructor.
754 javaTyConTypeName :: TyCon -> TypeName
755 javaTyConTypeName n = (moduleString (nameModule n') ++ "." ++ renameForKeywords n')
759 -- this is used for getting the name of a class when defining it.
760 shortName :: TypeName -> TypeName
761 shortName = reverse . takeWhile (/= '.') . reverse
763 -- The function that makes the constructor name
764 -- The constructor "Foo ..." in module Test,
765 -- would return the name "Test.Foo".
767 javaConstrWkrName :: DataCon -> TypeName
768 javaConstrWkrName = javaIdTypeName . dataConId
770 -- Makes x_inst for Rec decls
771 -- They are *never* is primitive
772 -- and always have local (type) names.
773 javaInstName :: Id -> Name
774 javaInstName n = Name (renameForKeywords n ++ "zdi_inst")
775 (Type (renameForKeywords n))
778 %************************************************************************
780 \subsection{Types and type mangling}
782 %************************************************************************
786 codeType, thunkType, valueType :: Type
787 codeType = Type codeName
788 thunkType = Type thunkName
789 valueType = Type "haskell.runtime.Value"
790 vmType = Type "haskell.runtime.VMEngine"
793 objectType, stringType :: Type
794 objectType = Type "java.lang.Object"
795 stringType = Type "java.lang.String"
798 void = PrimType PrimVoid
801 inttype = PrimType PrimInt
804 chartype = PrimType PrimChar
807 bytetype = PrimType PrimByte
809 -- This lets you get inside a possible "Value" type,
810 -- to access the internal unboxed object.
811 access :: Expr -> Type -> Expr
812 access expr (PrimType prim) = accessPrim (Cast valueType expr) prim
813 access expr other = expr
815 accessPrim expr PrimInt = Call expr (Name "intValue" inttype) []
816 accessPrim expr PrimChar = Call expr (Name "charValue" chartype) []
817 accessPrim expr PrimByte = Call expr (Name "byteValue" bytetype) []
818 accessPrim expr other = pprPanic "accessPrim" (text (show other))
820 -- This is where we map from typename to types,
821 -- allowing to match possible primitive types.
822 mkType :: TypeName -> Type
823 mkType "PrelGHC.Intzh" = inttype
824 mkType "PrelGHC.Charzh" = chartype
825 mkType other = Type other
827 -- Turns a (global) Id into a Type (fully qualified name).
828 javaIdType :: Id -> Type
829 javaIdType = mkType . javaIdTypeName
831 javaLocalIdType :: Id -> Type
832 javaLocalIdType = primRepToType . idPrimRep
834 primRepToType ::PrimRep -> Type
835 primRepToType PtrRep = objectType
836 primRepToType IntRep = inttype
837 primRepToType CharRep = chartype
838 primRepToType Int8Rep = bytetype
839 primRepToType AddrRep = objectType
840 primRepToType other = pprPanic "primRepToType" (ppr other)
842 -- The function that makes the constructor name
843 javaConstrWkrType :: DataCon -> Type
844 javaConstrWkrType con = Type (javaConstrWkrName con)
847 %************************************************************************
849 \subsection{Class Lifting}
851 %************************************************************************
853 This is a very simple class lifter. It works by carrying inwards a
854 list of bound variables (things that might need to be passed to a
856 * Any variable references is check with this list, and if it is
857 bound, then it is not top level, external reference.
858 * This means that for the purposes of lifting, it might be free
859 inside a lifted inner class.
860 * We remember these "free inside the inner class" values, and
861 use this list (which is passed, via the monad, outwards)
868 combine :: [Name] -> [Name] -> [Name]
869 combine [] names = names
870 combine names [] = names
871 combine (name:names) (name':names')
872 | name < name' = name : combine names (name':names')
873 | name > name' = name' : combine (name:names) names'
874 | name == name = name : combine names names'
875 | otherwise = error "names are not a total order"
877 both :: [Name] -> [Name] -> [Name]
880 both (name:names) (name':names')
881 | name < name' = both names (name':names')
882 | name > name' = both (name:names) names'
883 | name == name = name : both names names'
884 | otherwise = error "names are not a total order"
886 combineEnv :: Env -> [Name] -> Env
887 combineEnv (Env bound env) new = Env (bound `combine` new) env
889 addTypeMapping :: TypeName -> TypeName -> [Name] -> Env -> Env
890 addTypeMapping origName newName frees (Env bound env)
891 = Env bound ((origName,(newName,frees)) : env)
893 -- This a list of bound vars (with types)
894 -- and a mapping from old class name
895 -- to inner class name (with a list of frees that need passed
896 -- to the inner class.)
898 data Env = Env Bound [(TypeName,(TypeName,[Name]))]
901 LifterM { unLifterM ::
902 TypeName -> -- this class name
903 Int -> -- uniq supply
906 , [Decl] -- lifted classes
911 instance Monad LifterM where
912 return a = LifterM (\ n s -> (a,[],[],s))
913 (LifterM m) >>= fn = LifterM (\ n s ->
916 -> case unLifterM (fn a) n s of
917 (a,frees2,lifted2,s) -> ( a
918 , combine frees frees2
923 liftAccess :: Env -> Name -> LifterM ()
924 liftAccess env@(Env bound _) name
925 | name `elem` bound = LifterM (\ n s -> ((),[name],[],s))
926 | otherwise = return ()
928 scopedName :: TypeName -> LifterM a -> LifterM a
929 scopedName name (LifterM m) =
932 (a,frees,lifted,_) -> (a,frees,lifted,s)
935 genAnonInnerClassName :: LifterM TypeName
936 genAnonInnerClassName = LifterM (\ n s ->
944 genInnerClassName :: TypeName -> LifterM TypeName
945 genInnerClassName name = LifterM (\ n s ->
953 getFrees :: LifterM a -> LifterM (a,Frees)
954 getFrees (LifterM m) = LifterM (\ n s ->
956 (a,frees,lifted,n) -> ((a,frees),frees,lifted,n)
959 rememberClass :: Decl -> LifterM ()
960 rememberClass decl = LifterM (\ n s -> ((),[],[decl],s))
963 liftCompilationUnit :: CompilationUnit -> CompilationUnit
964 liftCompilationUnit (Package name ds) =
965 Package name (concatMap liftCompilationUnit' ds)
967 liftCompilationUnit' :: Decl -> [Decl]
968 liftCompilationUnit' decl =
969 case unLifterM (liftDecls True (Env [] []) [decl]) [] 1 of
970 (ds,_,ds',_) -> ds ++ ds'
973 -- The bound vars for the current class have
974 -- already be captured before calling liftDecl,
975 -- because they are in scope everywhere inside the class.
977 liftDecl :: Bool -> Env -> Decl -> LifterM Decl
978 liftDecl = \ top env decl ->
980 { Import n -> return (Import n)
982 do { e <- liftMaybeExpr env e
983 ; return (Field mfs (liftName env n) e)
985 ; Constructor mfs n as ss ->
986 do { let newBound = getBoundAtParameters as
987 ; (ss,_) <- liftStatements (combineEnv env newBound) ss
988 ; return (Constructor mfs n (liftParameters env as) ss)
990 ; Method mfs n as ts ss ->
991 do { let newBound = getBoundAtParameters as
992 ; (ss,_) <- liftStatements (combineEnv env newBound) ss
993 ; return (Method mfs (liftName env n) (liftParameters env as) ts ss)
995 ; Comment s -> return (Comment s)
996 ; Interface mfs n is ms -> error "interfaces not supported"
997 ; Class mfs n x is ms ->
998 do { let newBound = getBoundAtDecls ms
1000 (liftDecls False (combineEnv env newBound) ms)
1001 ; return (Class mfs n x is ms)
1005 liftDecls :: Bool -> Env -> [Decl] -> LifterM [Decl]
1006 liftDecls top env = mapM (liftDecl top env)
1008 getBoundAtDecls :: [Decl] -> Bound
1009 getBoundAtDecls = foldr combine [] . map getBoundAtDecl
1011 getBoundAtDecl :: Decl -> Bound
1012 getBoundAtDecl (Field _ n _) = [n]
1013 getBoundAtDecl _ = []
1015 getBoundAtParameters :: [Parameter] -> Bound
1016 getBoundAtParameters = foldr combine [] . map getBoundAtParameter
1019 getBoundAtParameter :: Parameter -> Bound
1020 getBoundAtParameter (Parameter _ n) = [n]
1023 liftStatement :: Env -> Statement -> LifterM (Statement,Env)
1024 liftStatement = \ env stmt ->
1026 { Skip -> return (stmt,env)
1027 ; Return e -> do { e <- liftExpr env e
1028 ; return (Return e,env)
1030 ; Block ss -> do { (ss,env) <- liftStatements env ss
1031 ; return (Block ss,env)
1033 ; ExprStatement e -> do { e <- liftExpr env e
1034 ; return (ExprStatement e,env)
1036 ; Declaration decl@(Field mfs n e) ->
1037 do { e <- liftMaybeExpr env e
1038 ; return ( Declaration (Field mfs (liftName env n) e)
1039 , env `combineEnv` getBoundAtDecl decl
1042 ; Declaration decl@(Class mfs n x is ms) ->
1043 do { innerName <- genInnerClassName n
1044 ; frees <- liftClass env innerName ms x is
1045 ; return ( Declaration (Comment ["lifted " ++ n])
1046 , addTypeMapping n innerName frees env
1049 ; Declaration d -> error "general Decl not supported"
1050 ; IfThenElse ecs s -> ifthenelse env ecs s
1051 ; Switch e as d -> error "switch not supported"
1055 -> [(Expr,Statement)]
1056 -> (Maybe Statement)
1057 -> LifterM (Statement,Env)
1058 ifthenelse env pairs may_stmt =
1059 do { let (exprs,stmts) = unzip pairs
1060 ; exprs <- liftExprs env exprs
1061 ; (stmts,_) <- liftStatements env stmts
1062 ; may_stmt <- case may_stmt of
1063 Just stmt -> do { (stmt,_) <- liftStatement env stmt
1064 ; return (Just stmt)
1066 Nothing -> return Nothing
1067 ; return (IfThenElse (zip exprs stmts) may_stmt,env)
1070 liftStatements :: Env -> [Statement] -> LifterM ([Statement],Env)
1071 liftStatements env [] = return ([],env)
1072 liftStatements env (s:ss) =
1073 do { (s,env) <- liftStatement env s
1074 ; (ss,env) <- liftStatements env ss
1078 liftExpr :: Env -> Expr -> LifterM Expr
1079 liftExpr = \ env expr ->
1081 { Var n -> do { liftAccess env n
1082 ; return (Var (liftName env n))
1084 ; Literal l -> return expr
1085 ; Cast t e -> do { e <- liftExpr env e
1086 ; return (Cast (liftType env t) e)
1088 ; Access e n -> do { e <- liftExpr env e
1089 -- do not consider n as an access, because
1090 -- this is a indirection via a reference
1091 ; return (Access e n)
1093 ; Assign l r -> do { l <- liftExpr env l
1094 ; r <- liftExpr env r
1095 ; return (Assign l r)
1097 ; InstanceOf e t -> do { e <- liftExpr env e
1098 ; return (InstanceOf e (liftType env t))
1100 ; Raise n es -> do { es <- liftExprs env es
1101 ; return (Raise n es)
1103 ; Call e n es -> do { e <- liftExpr env e
1104 ; es <- mapM (liftExpr env) es
1105 ; return (Call e n es)
1107 ; Op e1 o e2 -> do { e1 <- liftExpr env e1
1108 ; e2 <- liftExpr env e2
1109 ; return (Op e1 o e2)
1111 ; New n es ds -> new env n es ds
1114 liftParameter env (Parameter ms n) = Parameter ms (liftName env n)
1115 liftParameters env = map (liftParameter env)
1117 liftName env (Name n t) = Name n (liftType env t)
1119 liftExprs :: Env -> [Expr] -> LifterM [Expr]
1120 liftExprs = mapM . liftExpr
1123 liftMaybeExpr :: Env -> (Maybe Expr) -> LifterM (Maybe Expr)
1124 liftMaybeExpr env Nothing = return Nothing
1125 liftMaybeExpr env (Just stmt) = do { stmt <- liftExpr env stmt
1126 ; return (Just stmt)
1131 new :: Env -> Type -> [Expr] -> Maybe [Decl] -> LifterM Expr
1132 new env@(Env _ pairs) typ args Nothing =
1133 do { args <- liftExprs env args
1134 ; return (liftNew env typ args)
1136 new env typ [] (Just inner) =
1137 -- anon. inner class
1138 do { innerName <- genAnonInnerClassName
1139 ; frees <- liftClass env innerName inner [] [unType typ]
1140 ; return (New (Type (innerName))
1144 where unType (Type name) = name
1145 unType _ = error "incorrect type style"
1146 new env typ _ (Just inner) = error "cant handle inner class with args"
1149 liftClass :: Env -> TypeName -> [Decl] -> [TypeName] -> [TypeName] -> LifterM [ Name ]
1150 liftClass env@(Env bound _) innerName inner xs is =
1151 do { let newBound = getBoundAtDecls inner
1153 getFrees (liftDecls False (env `combineEnv` newBound) inner)
1154 ; let trueFrees = filter (\ (Name xs _) -> xs /= "VM") (both frees bound)
1155 ; let freeDefs = [ Field [Final] n Nothing | n <- trueFrees ]
1156 ; let cons = mkCons innerName trueFrees
1157 ; let innerClass = Class [] innerName xs is (freeDefs ++ [cons] ++ inner)
1158 ; rememberClass innerClass
1162 liftType :: Env -> Type -> Type
1163 liftType (Env _ env) typ@(Type name)
1164 = case lookup name env of
1166 Just (nm,_) -> Type nm
1167 liftType _ typ = typ
1169 liftNew :: Env -> Type -> [Expr] -> Expr
1170 liftNew (Env _ env) typ@(Type name) exprs
1171 = case lookup name env of
1172 Nothing -> New typ exprs Nothing
1173 Just (nm,args) | null exprs
1174 -> New (Type nm) (map Var args) Nothing
1175 _ -> error "pre-lifted constructor with arguments"