X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FdeSugar%2FDsExpr.lhs;h=162ae247c756a0354bd91b4514f18d28a6646c71;hb=20d7560469e59d78c17992ce4be75360c91587bb;hp=6e2efa07885d70a15a91c22379a3e99e3910c602;hpb=1bba522f5ec82c43abd2ba4e84127b9c915dd020;p=ghc-hetmet.git diff --git a/ghc/compiler/deSugar/DsExpr.lhs b/ghc/compiler/deSugar/DsExpr.lhs index 6e2efa0..162ae24 100644 --- a/ghc/compiler/deSugar/DsExpr.lhs +++ b/ghc/compiler/deSugar/DsExpr.lhs @@ -11,12 +11,20 @@ module DsExpr ( dsExpr, dsLet ) where import HsSyn ( failureFreePat, HsExpr(..), OutPat(..), HsLit(..), ArithSeqInfo(..), - Stmt(..), StmtCtxt(..), Match(..), HsBinds(..), MonoBinds(..), - mkSimpleMatch - ) -import TcHsSyn ( TypecheckedHsExpr, TypecheckedHsBinds, - TypecheckedStmt + Stmt(..), HsMatchContext(..), HsDoContext(..), + Match(..), HsBinds(..), MonoBinds(..), + mkSimpleMatch ) +import TcHsSyn ( TypecheckedHsExpr, TypecheckedHsBinds, TypecheckedStmt, outPatType ) + +-- NB: The desugarer, which straddles the source and Core worlds, sometimes +-- needs to see source types (newtypes etc), and sometimes not +-- So WATCH OUT; check each use of split*Ty functions. +-- Sigh. This is a pain. + +import TcType ( tcSplitAppTy, tcSplitFunTys, tcSplitTyConApp_maybe, tcTyConAppArgs, + isIntegerTy, tcSplitTyConApp, isUnLiftedType, Type ) +import Type ( splitFunTys ) import CoreSyn import CoreUtils ( exprType, mkIfThenElse, bindNonRec ) @@ -25,26 +33,23 @@ import DsBinds ( dsMonoBinds, AutoScc(..) ) import DsGRHSs ( dsGuarded ) import DsCCall ( dsCCall, resultWrapper ) import DsListComp ( dsListComp ) -import DsUtils ( mkErrorAppDs, mkDsLets, mkStringLit, mkStringLitFS, +import DsUtils ( mkErrorAppDs, mkStringLit, mkStringLitFS, mkConsExpr, mkNilExpr, mkIntegerLit ) import Match ( matchWrapper, matchSimply ) +import FieldLabel ( FieldLabel, fieldLabelTyCon ) import CostCentre ( mkUserCC ) import Id ( Id, idType, recordSelectorFieldLabel ) import PrelInfo ( rEC_CON_ERROR_ID, iRREFUT_PAT_ERROR_ID ) -import DataCon ( DataCon, dataConWrapId, dataConArgTys, dataConFieldLabels ) +import DataCon ( DataCon, dataConWrapId, dataConFieldLabels, dataConInstOrigArgTys ) import DataCon ( isExistentialDataCon ) import Literal ( Literal(..) ) -import Type ( splitFunTys, - splitAlgTyConApp, splitAlgTyConApp_maybe, splitTyConApp_maybe, - isNotUsgTy, unUsgTy, - splitAppTy, isUnLiftedType, Type - ) -import TysWiredIn ( tupleCon, listTyCon, charDataCon, intDataCon, isIntegerTy ) -import BasicTypes ( RecFlag(..), Boxity(..) ) +import TyCon ( tyConDataCons ) +import TysWiredIn ( tupleCon, listTyCon, charDataCon, intDataCon ) +import BasicTypes ( RecFlag(..), Boxity(..), ipNameName ) import Maybes ( maybeToBool ) -import Unique ( hasKey, ratioTyConKey ) +import PrelNames ( hasKey, ratioTyConKey ) import Util ( zipEqual, zipWithEqual ) import Outputable @@ -80,31 +85,56 @@ dsLet (ThenBinds b1 b2) body dsLet b1 body' -- Special case for bindings which bind unlifted variables +-- We need to do a case right away, rather than building +-- a tuple and doing selections. -- Silently ignore INLINE pragmas... -dsLet (MonoBind (AbsBinds [] [] binder_triples inlines - (PatMonoBind pat grhss loc)) sigs is_rec) body - | or [isUnLiftedType (idType g) | (_, g, l) <- binder_triples] +dsLet bind@(MonoBind (AbsBinds [] [] exports inlines binds) sigs is_rec) body + | or [isUnLiftedType (idType g) | (_, g, l) <- exports] = ASSERT (case is_rec of {NonRecursive -> True; other -> False}) - putSrcLocDs loc $ - dsGuarded grhss `thenDs` \ rhs -> - let - body' = foldr bind body binder_triples - bind (tyvars, g, l) body = ASSERT( null tyvars ) - bindNonRec g (Var l) body - in - mkErrorAppDs iRREFUT_PAT_ERROR_ID result_ty (showSDoc (ppr pat)) - `thenDs` \ error_expr -> - matchSimply rhs PatBindMatch pat body' error_expr + -- Unlifted bindings are always non-recursive + -- and are always a Fun or Pat monobind + -- + -- ToDo: in some bizarre case it's conceivable that there + -- could be dict binds in the 'binds'. (See the notes + -- below. Then pattern-match would fail. Urk.) + case binds of + FunMonoBind fun _ matches loc + -> putSrcLocDs loc $ + matchWrapper (FunRhs fun) matches `thenDs` \ (args, rhs) -> + ASSERT( null args ) -- Functions aren't lifted + returnDs (bindNonRec fun rhs body_w_exports) + + PatMonoBind pat grhss loc + -> putSrcLocDs loc $ + dsGuarded grhss `thenDs` \ rhs -> + mk_error_app pat `thenDs` \ error_expr -> + matchSimply rhs PatBindRhs pat body_w_exports error_expr + + other -> pprPanic "dsLet: unlifted" (ppr bind $$ ppr body) where - result_ty = exprType body + body_w_exports = foldr bind_export body exports + bind_export (tvs, g, l) body = ASSERT( null tvs ) + bindNonRec g (Var l) body + + mk_error_app pat = mkErrorAppDs iRREFUT_PAT_ERROR_ID + (exprType body) + (showSDoc (ppr pat)) -- Ordinary case for bindings dsLet (MonoBind binds sigs is_rec) body = dsMonoBinds NoSccs binds [] `thenDs` \ prs -> - case is_rec of - Recursive -> returnDs (Let (Rec prs) body) - NonRecursive -> returnDs (mkDsLets [NonRec b r | (b,r) <- prs] body) -\end{code} + returnDs (Let (Rec prs) body) + -- Use a Rec regardless of is_rec. + -- Why? Because it allows the MonoBinds to be all + -- mixed up, which is what happens in one rare case + -- Namely, for an AbsBind with no tyvars and no dicts, + -- but which does have dictionary bindings. + -- See notes with TcSimplify.inferLoop [NO TYVARS] + -- It turned out that wrapping a Rec here was the easiest solution + -- + -- NB The previous case dealt with unlifted bindings, so we + -- only have to deal with lifted ones now; so Rec is ok +\end{code} %************************************************************************ %* * @@ -115,20 +145,19 @@ dsLet (MonoBind binds sigs is_rec) body \begin{code} dsExpr :: TypecheckedHsExpr -> DsM CoreExpr -dsExpr (HsVar var) = returnDs (Var var) -dsExpr (HsIPVar var) = returnDs (Var var) -dsExpr (HsLit lit) = dsLit lit +dsExpr (HsVar var) = returnDs (Var var) +dsExpr (HsIPVar ip) = returnDs (Var (ipNameName ip)) +dsExpr (HsLit lit) = dsLit lit -- HsOverLit has been gotten rid of by the type checker dsExpr expr@(HsLam a_Match) - = matchWrapper LambdaMatch [a_Match] "lambda" `thenDs` \ (binders, matching_code) -> + = matchWrapper LambdaExpr [a_Match] `thenDs` \ (binders, matching_code) -> returnDs (mkLams binders matching_code) dsExpr expr@(HsApp fun arg) = dsExpr fun `thenDs` \ core_fun -> dsExpr arg `thenDs` \ core_arg -> returnDs (core_fun `App` core_arg) - \end{code} Operator sections. At first it looks as if we can convert @@ -165,6 +194,8 @@ dsExpr (SectionL expr op) -- for the type of y, we need the type of op's 2nd argument let (x_ty:y_ty:_, _) = splitFunTys (exprType core_op) + -- Must look through an implicit-parameter type; + -- newtype impossible; hence Type.splitFunTys in dsExpr expr `thenDs` \ x_core -> newSysLocalDs x_ty `thenDs` \ x_id -> @@ -179,6 +210,7 @@ dsExpr (SectionR op expr) -- for the type of x, we need the type of op's 2nd argument let (x_ty:y_ty:_, _) = splitFunTys (exprType core_op) + -- See comment with SectionL in dsExpr expr `thenDs` \ y_core -> newSysLocalDs x_ty `thenDs` \ x_id -> @@ -202,20 +234,20 @@ dsExpr (HsSCC cc expr) dsExpr (HsCase discrim matches src_loc) | all ubx_tuple_match matches = putSrcLocDs src_loc $ - dsExpr discrim `thenDs` \ core_discrim -> - matchWrapper CaseMatch matches "case" `thenDs` \ ([discrim_var], matching_code) -> + dsExpr discrim `thenDs` \ core_discrim -> + matchWrapper CaseAlt matches `thenDs` \ ([discrim_var], matching_code) -> case matching_code of Case (Var x) bndr alts | x == discrim_var -> returnDs (Case core_discrim bndr alts) _ -> panic ("dsExpr: tuple pattern:\n" ++ showSDoc (ppr matching_code)) where - ubx_tuple_match (Match _ [TuplePat ps Unboxed] _ _) = True + ubx_tuple_match (Match [TuplePat ps Unboxed] _ _) = True ubx_tuple_match _ = False dsExpr (HsCase discrim matches src_loc) = putSrcLocDs src_loc $ - dsExpr discrim `thenDs` \ core_discrim -> - matchWrapper CaseMatch matches "case" `thenDs` \ ([discrim_var], matching_code) -> + dsExpr discrim `thenDs` \ core_discrim -> + matchWrapper CaseAlt matches `thenDs` \ ([discrim_var], matching_code) -> returnDs (bindNonRec discrim_var core_discrim matching_code) dsExpr (HsLet binds body) @@ -228,7 +260,7 @@ dsExpr (HsWith expr binds) where dsIPBind body (n, e) = dsExpr e `thenDs` \ e' -> - returnDs (Let (NonRec n e') body) + returnDs (Let (NonRec (ipNameName n) e') body) dsExpr (HsDoOut do_or_lc stmts return_id then_id fail_id result_ty src_loc) | maybeToBool maybe_list_comp @@ -241,14 +273,14 @@ dsExpr (HsDoOut do_or_lc stmts return_id then_id fail_id result_ty src_loc) dsDo do_or_lc stmts return_id then_id fail_id result_ty where maybe_list_comp - = case (do_or_lc, splitTyConApp_maybe result_ty) of + = case (do_or_lc, tcSplitTyConApp_maybe result_ty) of (ListComp, Just (tycon, [elt_ty])) | tycon == listTyCon -> Just elt_ty other -> Nothing -- We need the ListComp form to use deListComp (rather than the "do" form) - -- because the "return" in a do block is a call to "PrelBase.return", and - -- not a ReturnStmt. Only the ListComp form has ReturnStmts + -- because the interpretation of ExprStmt depends on what sort of thing + -- it is. Just elt_ty = maybe_list_comp @@ -279,20 +311,18 @@ dsExpr (TyApp expr tys) \underline{\bf Various data construction things} % ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ \begin{code} -dsExpr (ExplicitListOut ty xs) +dsExpr (ExplicitList ty xs) = go xs where go [] = returnDs (mkNilExpr ty) go (x:xs) = dsExpr x `thenDs` \ core_x -> go xs `thenDs` \ core_xs -> - ASSERT( isNotUsgTy ty ) returnDs (mkConsExpr ty core_x core_xs) dsExpr (ExplicitTuple expr_list boxity) = mapDs dsExpr expr_list `thenDs` \ core_exprs -> returnDs (mkConApp (tupleCon boxity (length expr_list)) - (map (Type . unUsgTy . exprType) core_exprs ++ core_exprs)) - -- the above unUsgTy is *required* -- KSW 1999-04-07 + (map (Type . exprType) core_exprs ++ core_exprs)) dsExpr (ArithSeqOut expr (From from)) = dsExpr expr `thenDs` \ expr2 -> @@ -344,7 +374,9 @@ constructor @C@, setting all of @C@'s fields to bottom. dsExpr (RecordConOut data_con con_expr rbinds) = dsExpr con_expr `thenDs` \ con_expr' -> let - (arg_tys, _) = splitFunTys (exprType con_expr') + (arg_tys, _) = tcSplitFunTys (exprType con_expr') + -- A newtype in the corner should be opaque; + -- hence TcType.tcSplitFunTys mk_arg (arg_ty, lbl) = case [rhs | (sel_id,rhs,_) <- rbinds, @@ -387,18 +419,19 @@ might do some argument-evaluation first; and may have to throw away some dictionaries. \begin{code} -dsExpr (RecordUpdOut record_expr record_out_ty dicts rbinds) - = getSrcLocDs `thenDs` \ src_loc -> +dsExpr (RecordUpdOut record_expr record_in_ty record_out_ty dicts []) + = dsExpr record_expr + +dsExpr (RecordUpdOut record_expr record_in_ty record_out_ty dicts rbinds) + = getSrcLocDs `thenDs` \ src_loc -> dsExpr record_expr `thenDs` \ record_expr' -> -- Desugar the rbinds, and generate let-bindings if -- necessary so that we don't lose sharing let - record_in_ty = exprType record_expr' - (_, in_inst_tys, cons) = splitAlgTyConApp record_in_ty - (_, out_inst_tys, _) = splitAlgTyConApp record_out_ty - cons_to_upd = filter has_all_fields cons + in_inst_tys = tcTyConAppArgs record_in_ty -- Newtype opaque + out_inst_tys = tcTyConAppArgs record_out_ty -- Newtype opaque mk_val_arg field old_arg_id = case [rhs | (sel_id, rhs, _) <- rbinds, @@ -407,7 +440,7 @@ dsExpr (RecordUpdOut record_expr record_out_ty dicts rbinds) [] -> HsVar old_arg_id mk_alt con - = newSysLocalsDs (dataConArgTys con in_inst_tys) `thenDs` \ arg_ids -> + = newSysLocalsDs (dataConInstOrigArgTys con in_inst_tys) `thenDs` \ arg_ids -> -- This call to dataConArgTys won't work for existentials let val_args = zipWithEqual "dsExpr:RecordUpd" mk_val_arg @@ -419,28 +452,38 @@ dsExpr (RecordUpdOut record_expr record_out_ty dicts rbinds) in returnDs (mkSimpleMatch [ConPat con record_in_ty [] [] (map VarPat arg_ids)] rhs - (Just record_out_ty) + record_out_ty src_loc) in -- Record stuff doesn't work for existentials - ASSERT( all (not . isExistentialDataCon) cons ) + ASSERT( all (not . isExistentialDataCon) data_cons ) -- It's important to generate the match with matchWrapper, -- and the right hand sides with applications of the wrapper Id -- so that everything works when we are doing fancy unboxing on the -- constructor aguments. - mapDs mk_alt cons_to_upd `thenDs` \ alts -> - matchWrapper RecUpdMatch alts "record update" `thenDs` \ ([discrim_var], matching_code) -> + mapDs mk_alt cons_to_upd `thenDs` \ alts -> + matchWrapper RecUpd alts `thenDs` \ ([discrim_var], matching_code) -> returnDs (bindNonRec discrim_var record_expr' matching_code) where + updated_fields :: [FieldLabel] + updated_fields = [recordSelectorFieldLabel sel_id | (sel_id,_,_) <- rbinds] + + -- Get the type constructor from the first field label, + -- so that we are sure it'll have all its DataCons + -- (In GHCI, it's possible that some TyCons may not have all + -- their constructors, in a module-loop situation.) + tycon = fieldLabelTyCon (head updated_fields) + data_cons = tyConDataCons tycon + cons_to_upd = filter has_all_fields data_cons + has_all_fields :: DataCon -> Bool has_all_fields con_id - = all ok rbinds + = all (`elem` con_fields) updated_fields where - con_fields = dataConFieldLabels con_id - ok (sel_id, _, _) = recordSelectorFieldLabel sel_id `elem` con_fields + con_fields = dataConFieldLabels con_id \end{code} @@ -467,7 +510,6 @@ dsExpr (DictApp expr dicts) -- becomes a curried application #ifdef DEBUG -- HsSyn constructs that just shouldn't be here: dsExpr (HsDo _ _ _) = panic "dsExpr:HsDo" -dsExpr (ExplicitList _) = panic "dsExpr:ExplicitList" dsExpr (ExprWithTySig _ _) = panic "dsExpr:ExprWithTySig" dsExpr (ArithSeqIn _) = panic "dsExpr:ArithSeqIn" #endif @@ -479,7 +521,7 @@ dsExpr (ArithSeqIn _) = panic "dsExpr:ArithSeqIn" Basically does the translation given in the Haskell~1.3 report: \begin{code} -dsDo :: StmtCtxt +dsDo :: HsDoContext -> [TypecheckedStmt] -> Id -- id for: return m -> Id -- id for: (>>=) m @@ -489,37 +531,38 @@ dsDo :: StmtCtxt dsDo do_or_lc stmts return_id then_id fail_id result_ty = let - (_, b_ty) = splitAppTy result_ty -- result_ty must be of the form (m b) + (_, b_ty) = tcSplitAppTy result_ty -- result_ty must be of the form (m b) + is_do = case do_or_lc of + DoExpr -> True + ListComp -> False - go [ReturnStmt expr] - = dsExpr expr `thenDs` \ expr2 -> - returnDs (mkApps (Var return_id) [Type b_ty, expr2]) - - go (GuardStmt expr locn : stmts) + -- For ExprStmt, see the comments near HsExpr.Stmt about + -- exactly what ExprStmts mean! + -- + -- In dsDo we can only see DoStmt and ListComp (no gaurds) + + go [ResultStmt expr locn] + | is_do = do_expr expr locn + | otherwise = do_expr expr locn `thenDs` \ expr2 -> + returnDs (mkApps (Var return_id) [Type b_ty, expr2]) + + go (ExprStmt expr a_ty locn : stmts) + | is_do -- Do expression + = do_expr expr locn `thenDs` \ expr2 -> + go stmts `thenDs` \ rest -> + newSysLocalDs a_ty `thenDs` \ ignored_result_id -> + returnDs (mkApps (Var then_id) [Type a_ty, Type b_ty, expr2, + Lam ignored_result_id rest]) + + | otherwise -- List comprehension = do_expr expr locn `thenDs` \ expr2 -> go stmts `thenDs` \ rest -> - let msg = ASSERT( isNotUsgTy b_ty ) - "Pattern match failure in do expression, " ++ showSDoc (ppr locn) - in - mkStringLit msg `thenDs` \ core_msg -> - returnDs (mkIfThenElse expr2 - rest - (App (App (Var fail_id) - (Type b_ty)) - core_msg)) - - go (ExprStmt expr locn : stmts) - = do_expr expr locn `thenDs` \ expr2 -> let - (_, a_ty) = splitAppTy (exprType expr2) -- Must be of form (m a) + msg = "Pattern match failure in do expression, " ++ showSDoc (ppr locn) in - if null stmts then - returnDs expr2 - else - go stmts `thenDs` \ rest -> - newSysLocalDs a_ty `thenDs` \ ignored_result_id -> - returnDs (mkApps (Var then_id) [Type a_ty, Type b_ty, expr2, - Lam ignored_result_id rest]) + mkStringLit msg `thenDs` \ core_msg -> + returnDs (mkIfThenElse expr2 rest + (App (App (Var fail_id) (Type b_ty)) core_msg)) go (LetStmt binds : stmts ) = go stmts `thenDs` \ rest -> @@ -529,25 +572,22 @@ dsDo do_or_lc stmts return_id then_id fail_id result_ty = putSrcLocDs locn $ dsExpr expr `thenDs` \ expr2 -> let - (_, a_ty) = splitAppTy (exprType expr2) -- Must be of form (m a) + a_ty = outPatType pat fail_expr = HsApp (TyApp (HsVar fail_id) [b_ty]) (HsLit (HsString (_PK_ msg))) - msg = ASSERT2( isNotUsgTy a_ty, ppr a_ty ) - ASSERT2( isNotUsgTy b_ty, ppr b_ty ) - "Pattern match failure in do expression, " ++ showSDoc (ppr locn) + msg = "Pattern match failure in do expression, " ++ showSDoc (ppr locn) main_match = mkSimpleMatch [pat] (HsDoOut do_or_lc stmts return_id then_id fail_id result_ty locn) - (Just result_ty) locn + result_ty locn the_matches | failureFreePat pat = [main_match] | otherwise = [ main_match - , mkSimpleMatch [WildPat a_ty] fail_expr (Just result_ty) locn + , mkSimpleMatch [WildPat a_ty] fail_expr result_ty locn ] in - matchWrapper DoBindMatch the_matches match_msg - `thenDs` \ (binders, matching_code) -> + matchWrapper (DoCtxt do_or_lc) the_matches `thenDs` \ (binders, matching_code) -> returnDs (mkApps (Var then_id) [Type a_ty, Type b_ty, expr2, mkLams binders matching_code]) in @@ -555,10 +595,6 @@ dsDo do_or_lc stmts return_id then_id fail_id result_ty where do_expr expr locn = putSrcLocDs locn (dsExpr expr) - - match_msg = case do_or_lc of - DoStmt -> "`do' statement" - ListComp -> "comprehension" \end{code} @@ -604,14 +640,8 @@ dsLit (HsRat r ty) mkIntegerLit (denominator r) `thenDs` \ denom -> returnDs (mkConApp ratio_data_con [Type integer_ty, num, denom]) where - (ratio_data_con, integer_ty) - = case (splitAlgTyConApp_maybe ty) of - Just (tycon, [i_ty], [con]) - -> ASSERT(isIntegerTy i_ty && tycon `hasKey` ratioTyConKey) - (con, i_ty) - - _ -> (panic "ratio_data_con", panic "integer_ty") + (ratio_data_con, integer_ty) + = case tcSplitTyConApp ty of + (tycon, [i_ty]) -> ASSERT(isIntegerTy i_ty && tycon `hasKey` ratioTyConKey) + (head (tyConDataCons tycon), i_ty) \end{code} - - -