mkCoLetsMatchResult, mkGuardedMatchResult,
mkCoPrimCaseMatchResult, mkCoAlgCaseMatchResult,
- mkErrorAppDs, mkNilExpr, mkConsExpr,
- mkStringLit, mkStringLitFS, mkIntegerLit,
+ mkErrorAppDs, mkNilExpr, mkConsExpr, mkListExpr,
+ mkIntExpr, mkCharExpr,
+ mkStringLit, mkStringLitFS, mkIntegerExpr,
- mkSelectorBinds, mkTupleExpr, mkTupleSelector,
+ mkSelectorBinds, mkTupleExpr, mkTupleSelector,
+ mkCoreTup, mkCoreSel, mkCoreTupTy,
selectMatchVar
) where
import {-# SOURCE #-} Match ( matchSimply )
import HsSyn
-import TcHsSyn ( TypecheckedPat, outPatType, collectTypedPatBinders )
+import TcHsSyn ( TypecheckedPat, hsPatType )
import CoreSyn
-
+import Constants ( mAX_TUPLE_SIZE )
import DsMonad
-import CoreUtils ( exprType, mkIfThenElse )
-import PrelInfo ( iRREFUT_PAT_ERROR_ID )
-import MkId ( rebuildConArgs )
-import Id ( idType, Id, mkWildId )
+import CoreUtils ( exprType, mkIfThenElse, mkCoerce )
+import MkId ( iRREFUT_PAT_ERROR_ID, mkReboxingAlt, mkNewTypeBody )
+import Id ( idType, Id, mkWildId, mkTemplateLocals )
import Literal ( Literal(..), inIntRange, tARGET_MAX_INT )
-import TyCon ( isNewTyCon, tyConDataCons, isRecursiveTyCon )
-import DataCon ( DataCon, dataConStrictMarks, dataConId )
-import Type ( mkFunTy, isUnLiftedType, Type )
+import TyCon ( isNewTyCon, tyConDataCons )
+import DataCon ( DataCon, dataConSourceArity )
+import Type ( mkFunTy, isUnLiftedType, Type, splitTyConApp )
import TcType ( tcTyConAppTyCon, isIntTy, isFloatTy, isDoubleTy )
-import TysPrim ( intPrimTy, charPrimTy, floatPrimTy, doublePrimTy )
+import TysPrim ( intPrimTy )
import TysWiredIn ( nilDataCon, consDataCon,
- tupleCon,
+ tupleCon, mkTupleTy,
unitDataConId, unitTy,
charTy, charDataCon,
- intDataCon, smallIntegerDataCon,
+ intTy, intDataCon, smallIntegerDataCon,
floatDataCon,
doubleDataCon,
- stringTy
- )
+ stringTy, isPArrFakeCon )
import BasicTypes ( Boxity(..) )
import UniqSet ( mkUniqSet, minusUniqSet, isEmptyUniqSet, UniqSet )
import PrelNames ( unpackCStringName, unpackCStringUtf8Name,
- plusIntegerName, timesIntegerName )
+ plusIntegerName, timesIntegerName,
+ lengthPName, indexPName )
import Outputable
-import UnicodeUtil ( stringToUtf8 )
-import Util ( isSingleton )
+import UnicodeUtil ( intsToUtf8, stringToUtf8 )
+import Util ( isSingleton, notNull, zipEqual )
+import FastString
\end{code}
\begin{code}
tidyLitPat :: HsLit -> TypecheckedPat -> TypecheckedPat
-tidyLitPat (HsChar c) pat = ConPat charDataCon charTy [] [] [LitPat (HsCharPrim c) charPrimTy]
+tidyLitPat (HsChar c) pat = mkCharLitPat c
tidyLitPat lit pat = pat
tidyNPat :: HsLit -> Type -> TypecheckedPat -> TypecheckedPat
tidyNPat (HsString s) _ pat
- | _LENGTH_ s <= 1 -- Short string literals only
- = foldr (\c pat -> ConPat consDataCon stringTy [] [] [mk_char_lit c,pat])
- (ConPat nilDataCon stringTy [] [] []) (_UNPK_INT_ s)
+ | lengthFS s <= 1 -- Short string literals only
+ = foldr (\c pat -> mkPrefixConPat consDataCon [mkCharLitPat c,pat] stringTy)
+ (mkNilPat stringTy) (unpackIntFS s)
-- The stringTy is the type of the whole pattern, not
-- the type to instantiate (:) or [] with!
where
- mk_char_lit c = ConPat charDataCon charTy [] [] [LitPat (HsCharPrim c) charPrimTy]
tidyNPat lit lit_ty default_pat
- | isIntTy lit_ty = ConPat intDataCon lit_ty [] [] [LitPat (mk_int lit) intPrimTy]
- | isFloatTy lit_ty = ConPat floatDataCon lit_ty [] [] [LitPat (mk_float lit) floatPrimTy]
- | isDoubleTy lit_ty = ConPat doubleDataCon lit_ty [] [] [LitPat (mk_double lit) doublePrimTy]
+ | isIntTy lit_ty = mkPrefixConPat intDataCon [LitPat (mk_int lit)] lit_ty
+ | isFloatTy lit_ty = mkPrefixConPat floatDataCon [LitPat (mk_float lit)] lit_ty
+ | isDoubleTy lit_ty = mkPrefixConPat doubleDataCon [LitPat (mk_double lit)] lit_ty
| otherwise = default_pat
where
selectMatchVar (VarPat var) = returnDs var
selectMatchVar (AsPat var pat) = returnDs var
selectMatchVar (LazyPat pat) = selectMatchVar pat
-selectMatchVar other_pat = newSysLocalDs (outPatType other_pat) -- OK, better make up one...
+selectMatchVar other_pat = newSysLocalDs (hsPatType other_pat) -- OK, better make up one...
\end{code}
= ASSERT( null (tail match_alts) && null (tail arg_ids) )
mkCoLetsMatchResult [NonRec arg_id newtype_rhs] match_result
+ | isPArrFakeAlts match_alts -- Sugared parallel array; use a literal case
+ = MatchResult CanFail mk_parrCase
+
| otherwise -- Datatype case; use a case
= MatchResult fail_flag mk_case
where
-- Stuff for newtype
(_, arg_ids, match_result) = head match_alts
arg_id = head arg_ids
-
- newtype_rhs | isRecursiveTyCon tycon -- Recursive case; need a case
- = Note (Coerce (idType arg_id) scrut_ty) (Var var)
- | otherwise -- Normal case (newtype is transparent)
- = Var var
+ newtype_rhs = mkNewTypeBody tycon (idType arg_id) (Var var)
-- Stuff for data types
- data_cons = tyConDataCons tycon
-
- match_results = [match_result | (_,_,match_result) <- match_alts]
+ data_cons = tyConDataCons tycon
+ match_results = [match_result | (_,_,match_result) <- match_alts]
fail_flag | exhaustive_case
= foldr1 orFail [can_it_fail | MatchResult can_it_fail _ <- match_results]
returnDs (Case (Var var) wild_var (mk_default fail ++ alts))
mk_alt fail (con, args, MatchResult _ body_fn)
- = body_fn fail `thenDs` \ body ->
- getUniquesDs `thenDs` \ us ->
- let
- (binds, real_args) = rebuildConArgs args (dataConStrictMarks con) us
- in
- returnDs (DataAlt con, real_args, mkDsLets binds body)
+ = body_fn fail `thenDs` \ body ->
+ getUniquesDs `thenDs` \ us ->
+ returnDs (mkReboxingAlt us con args body)
mk_default fail | exhaustive_case = []
| otherwise = [(DEFAULT, [], fail)]
un_mentioned_constructors
= mkUniqSet data_cons `minusUniqSet` mkUniqSet [ con | (con, _, _) <- match_alts]
exhaustive_case = isEmptyUniqSet un_mentioned_constructors
+
+ -- Stuff for parallel arrays
+ --
+ -- * the following is to desugar cases over fake constructors for
+ -- parallel arrays, which are introduced by `tidy1' in the `PArrPat'
+ -- case
+ --
+ -- Concerning `isPArrFakeAlts':
+ --
+ -- * it is *not* sufficient to just check the type of the type
+ -- constructor, as we have to be careful not to confuse the real
+ -- representation of parallel arrays with the fake constructors;
+ -- moreover, a list of alternatives must not mix fake and real
+ -- constructors (this is checked earlier on)
+ --
+ -- FIXME: We actually go through the whole list and make sure that
+ -- either all or none of the constructors are fake parallel
+ -- array constructors. This is to spot equations that mix fake
+ -- constructors with the real representation defined in
+ -- `PrelPArr'. It would be nicer to spot this situation
+ -- earlier and raise a proper error message, but it can really
+ -- only happen in `PrelPArr' anyway.
+ --
+ isPArrFakeAlts [(dcon, _, _)] = isPArrFakeCon dcon
+ isPArrFakeAlts ((dcon, _, _):alts) =
+ case (isPArrFakeCon dcon, isPArrFakeAlts alts) of
+ (True , True ) -> True
+ (False, False) -> False
+ _ ->
+ panic "DsUtils: You may not mix `[:...:]' with `PArr' patterns"
+ --
+ mk_parrCase fail =
+ dsLookupGlobalId lengthPName `thenDs` \lengthP ->
+ unboxAlt `thenDs` \alt ->
+ returnDs (Case (len lengthP) (mkWildId intTy) [alt])
+ where
+ elemTy = case splitTyConApp (idType var) of
+ (_, [elemTy]) -> elemTy
+ _ -> panic panicMsg
+ panicMsg = "DsUtils.mkCoAlgCaseMatchResult: not a parallel array?"
+ len lengthP = mkApps (Var lengthP) [Type elemTy, Var var]
+ --
+ unboxAlt =
+ newSysLocalDs intPrimTy `thenDs` \l ->
+ dsLookupGlobalId indexPName `thenDs` \indexP ->
+ mapDs (mkAlt indexP) match_alts `thenDs` \alts ->
+ returnDs (DataAlt intDataCon, [l], (Case (Var l) wild (dft : alts)))
+ where
+ wild = mkWildId intPrimTy
+ dft = (DEFAULT, [], fail)
+ --
+ -- each alternative matches one array length (corresponding to one
+ -- fake array constructor), so the match is on a literal; each
+ -- alternative's body is extended by a local binding for each
+ -- constructor argument, which are bound to array elements starting
+ -- with the first
+ --
+ mkAlt indexP (con, args, MatchResult _ bodyFun) =
+ bodyFun fail `thenDs` \body ->
+ returnDs (LitAlt lit, [], mkDsLets binds body)
+ where
+ lit = MachInt $ toInteger (dataConSourceArity con)
+ binds = [NonRec arg (indexExpr i) | (i, arg) <- zip [1..] args]
+ --
+ indexExpr i = mkApps (Var indexP) [Type elemTy, Var var, mkIntExpr i]
\end{code}
= getSrcLocDs `thenDs` \ src_loc ->
let
full_msg = showSDoc (hcat [ppr src_loc, text "|", text msg])
+ core_msg = Lit (MachStr (mkFastString (stringToUtf8 full_msg)))
in
- mkStringLit full_msg `thenDs` \ core_msg ->
returnDs (mkApps (Var err_id) [Type ty, core_msg])
\end{code}
%************************************************************************
\begin{code}
-mkIntegerLit :: Integer -> DsM CoreExpr
-mkIntegerLit i
+mkCharExpr :: Int -> CoreExpr -- Returns C# c :: Int
+mkIntExpr :: Integer -> CoreExpr -- Returns I# i :: Int
+mkIntegerExpr :: Integer -> DsM CoreExpr -- Result :: Integer
+mkStringLit :: String -> DsM CoreExpr -- Result :: String
+mkStringLitFS :: FastString -> DsM CoreExpr -- Result :: String
+
+mkIntExpr i = mkConApp intDataCon [mkIntLit i]
+mkCharExpr c = mkConApp charDataCon [mkLit (MachChar c)]
+
+mkIntegerExpr i
| inIntRange i -- Small enough, so start from an Int
= returnDs (mkSmallIntegerLit i)
-- integral literals. This improves constant folding.
| otherwise -- Big, so start from a string
- = dsLookupGlobalValue plusIntegerName `thenDs` \ plus_id ->
- dsLookupGlobalValue timesIntegerName `thenDs` \ times_id ->
+ = dsLookupGlobalId plusIntegerName `thenDs` \ plus_id ->
+ dsLookupGlobalId timesIntegerName `thenDs` \ times_id ->
let
plus a b = Var plus_id `App` a `App` b
times a b = Var times_id `App` a `App` b
mkSmallIntegerLit i = mkConApp smallIntegerDataCon [mkIntLit i]
-mkStringLit :: String -> DsM CoreExpr
-mkStringLit str = mkStringLitFS (_PK_ str)
+mkStringLit str = mkStringLitFS (mkFastString str)
-mkStringLitFS :: FAST_STRING -> DsM CoreExpr
mkStringLitFS str
- | _NULL_ str
+ | nullFastString str
= returnDs (mkNilExpr charTy)
- | _LENGTH_ str == 1
+ | lengthFS str == 1
= let
- the_char = mkConApp charDataCon [mkLit (MachChar (_HEAD_INT_ str))]
+ the_char = mkCharExpr (headIntFS str)
in
returnDs (mkConsExpr charTy the_char (mkNilExpr charTy))
- | all safeChar chars
- = dsLookupGlobalValue unpackCStringName `thenDs` \ unpack_id ->
+ | all safeChar int_chars
+ = dsLookupGlobalId unpackCStringName `thenDs` \ unpack_id ->
returnDs (App (Var unpack_id) (Lit (MachStr str)))
| otherwise
- = dsLookupGlobalValue unpackCStringUtf8Name `thenDs` \ unpack_id ->
- returnDs (App (Var unpack_id) (Lit (MachStr (_PK_ (stringToUtf8 chars)))))
+ = dsLookupGlobalId unpackCStringUtf8Name `thenDs` \ unpack_id ->
+ returnDs (App (Var unpack_id) (Lit (MachStr (mkFastString (intsToUtf8 int_chars)))))
where
- chars = _UNPK_INT_ str
+ int_chars = unpackIntFS str
safeChar c = c >= 1 && c <= 0xFF
\end{code}
mkSelectorBinds pat val_expr
| isSingleton binders || is_simple_pat pat
- = newSysLocalDs (exprType val_expr) `thenDs` \ val_var ->
-
- -- For the error message we don't use mkErrorAppDs to avoid
- -- duplicating the string literal each time
- newSysLocalDs stringTy `thenDs` \ msg_var ->
- getSrcLocDs `thenDs` \ src_loc ->
- let
- full_msg = showSDoc (hcat [ppr src_loc, text "|", ppr pat])
- in
- mkStringLit full_msg `thenDs` \ core_msg ->
- mapDs (mk_bind val_var msg_var) binders `thenDs` \ binds ->
+ = -- Given p = e, where p binds x,y
+ -- we are going to make
+ -- v = p (where v is fresh)
+ -- x = case v of p -> x
+ -- y = case v of p -> x
+
+ -- Make up 'v'
+ -- NB: give it the type of *pattern* p, not the type of the *rhs* e.
+ -- This does not matter after desugaring, but there's a subtle
+ -- issue with implicit parameters. Consider
+ -- (x,y) = ?i
+ -- Then, ?i is given type {?i :: Int}, a SourceType, which is opaque
+ -- to the desugarer. (Why opaque? Because newtypes have to be. Why
+ -- does it get that type? So that when we abstract over it we get the
+ -- right top-level type (?i::Int) => ...)
+ --
+ -- So to get the type of 'v', use the pattern not the rhs. Often more
+ -- efficient too.
+ newSysLocalDs (hsPatType pat) `thenDs` \ val_var ->
+
+ -- For the error message we make one error-app, to avoid duplication.
+ -- But we need it at different types... so we use coerce for that
+ mkErrorAppDs iRREFUT_PAT_ERROR_ID
+ unitTy (showSDoc (ppr pat)) `thenDs` \ err_expr ->
+ newSysLocalDs unitTy `thenDs` \ err_var ->
+ mapDs (mk_bind val_var err_var) binders `thenDs` \ binds ->
returnDs ( (val_var, val_expr) :
- (msg_var, core_msg) :
+ (err_var, err_expr) :
binds )
| otherwise
- = mkErrorAppDs iRREFUT_PAT_ERROR_ID tuple_ty (showSDoc (ppr pat))
- `thenDs` \ error_expr ->
- matchSimply val_expr PatBindRhs pat local_tuple error_expr
- `thenDs` \ tuple_expr ->
- newSysLocalDs tuple_ty
- `thenDs` \ tuple_var ->
+ = mkErrorAppDs iRREFUT_PAT_ERROR_ID
+ tuple_ty (showSDoc (ppr pat)) `thenDs` \ error_expr ->
+ matchSimply val_expr PatBindRhs pat local_tuple error_expr `thenDs` \ tuple_expr ->
+ newSysLocalDs tuple_ty `thenDs` \ tuple_var ->
let
- mk_tup_bind binder =
- (binder, mkTupleSelector binders binder tuple_var (Var tuple_var))
+ mk_tup_bind binder
+ = (binder, mkTupleSelector binders binder tuple_var (Var tuple_var))
in
returnDs ( (tuple_var, tuple_expr) : map mk_tup_bind binders )
where
- binders = collectTypedPatBinders pat
+ binders = collectPatBinders pat
local_tuple = mkTupleExpr binders
tuple_ty = exprType local_tuple
- mk_bind scrut_var msg_var bndr_var
- -- (mk_bind sv bv) generates
- -- bv = case sv of { pat -> bv; other -> error-msg }
+ mk_bind scrut_var err_var bndr_var
+ -- (mk_bind sv err_var) generates
+ -- bv = case sv of { pat -> bv; other -> coerce (type-of-bv) err_var }
-- Remember, pat binds bv
= matchSimply (Var scrut_var) PatBindRhs pat
(Var bndr_var) error_expr `thenDs` \ rhs_expr ->
returnDs (bndr_var, rhs_expr)
where
- binder_ty = idType bndr_var
- error_expr = mkApps (Var iRREFUT_PAT_ERROR_ID) [Type binder_ty, Var msg_var]
+ error_expr = mkCoerce (idType bndr_var) (Var err_var)
- is_simple_pat (TuplePat ps Boxed) = all is_triv_pat ps
- is_simple_pat (ConPat _ _ _ _ ps) = all is_triv_pat ps
- is_simple_pat (VarPat _) = True
- is_simple_pat (RecPat _ _ _ _ ps) = and [is_triv_pat p | (_,p,_) <- ps]
- is_simple_pat other = False
+ is_simple_pat (TuplePat ps Boxed) = all is_triv_pat ps
+ is_simple_pat (ConPatOut _ ps _ _ _) = all is_triv_pat (hsConArgs ps)
+ is_simple_pat (VarPat _) = True
+ is_simple_pat (ParPat p) = is_simple_pat p
+ is_simple_pat other = False
is_triv_pat (VarPat v) = True
is_triv_pat (WildPat _) = True
+ is_triv_pat (ParPat p) = is_triv_pat p
is_triv_pat other = False
\end{code}
-@mkTupleExpr@ builds a tuple; the inverse to @mkTupleSelector@. If it
-has only one element, it is the identity function.
+%************************************************************************
+%* *
+ Tuples
+%* *
+%************************************************************************
+
+@mkTupleExpr@ builds a tuple; the inverse to @mkTupleSelector@.
+
+* If it has only one element, it is the identity function.
+
+* If there are more elements than a big tuple can have, it nests
+ the tuples.
+
+Nesting policy. Better a 2-tuple of 10-tuples (3 objects) than
+a 10-tuple of 2-tuples (11 objects). So we want the leaves to be big.
\begin{code}
mkTupleExpr :: [Id] -> CoreExpr
-
-mkTupleExpr [] = Var unitDataConId
-mkTupleExpr [id] = Var id
-mkTupleExpr ids = mkConApp (tupleCon Boxed (length ids))
- (map (Type . idType) ids ++ [ Var i | i <- ids ])
+mkTupleExpr ids
+ = mk_tuple_expr (chunkify (map Var ids))
+ where
+ mk_tuple_expr :: [[CoreExpr]] -> CoreExpr
+ -- Each sub-list is short enough to fit in a tuple
+ mk_tuple_expr [exprs] = mkCoreTup exprs
+ mk_tuple_expr exprs_s = mk_tuple_expr (chunkify (map mkCoreTup exprs_s))
+
+
+chunkify :: [a] -> [[a]]
+-- The sub-lists of the result all have length <= mAX_TUPLE_SIZE
+-- But there may be more than mAX_TUPLE_SIZE sub-lists
+chunkify xs
+ | n_xs <= mAX_TUPLE_SIZE = {- pprTrace "Small" (ppr n_xs) -} [xs]
+ | otherwise = {- pprTrace "Big" (ppr n_xs) -} (split xs)
+ where
+ n_xs = length xs
+ split [] = []
+ split xs = take mAX_TUPLE_SIZE xs : split (drop mAX_TUPLE_SIZE xs)
\end{code}
If there is just one id in the ``tuple'', then the selector is
just the identity.
+If it's big, it does nesting
+ mkTupleSelector [a,b,c,d] b v e
+ = case e of v {
+ (p,q) -> case p of p {
+ (a,b) -> b }}
+We use 'tpl' vars for the p,q, since shadowing does not matter.
+
+In fact, it's more convenient to generate it innermost first, getting
+
+ case (case e of v
+ (p,q) -> p) of p
+ (a,b) -> b
+
\begin{code}
mkTupleSelector :: [Id] -- The tuple args
-> Id -- The selected one
-> CoreExpr -- Scrutinee
-> CoreExpr
-mkTupleSelector [var] should_be_the_same_var scrut_var scrut
- = ASSERT(var == should_be_the_same_var)
- scrut
-
mkTupleSelector vars the_var scrut_var scrut
- = ASSERT( not (null vars) )
- Case scrut scrut_var [(DataAlt (tupleCon Boxed (length vars)), vars, Var the_var)]
+ = mk_tup_sel (chunkify vars) the_var
+ where
+ mk_tup_sel [vars] the_var = mkCoreSel vars the_var scrut_var scrut
+ mk_tup_sel vars_s the_var = mkCoreSel group the_var tpl_v $
+ mk_tup_sel (chunkify tpl_vs) tpl_v
+ where
+ tpl_tys = [mkCoreTupTy (map idType gp) | gp <- vars_s]
+ tpl_vs = mkTemplateLocals tpl_tys
+ [(tpl_v, group)] = [(tpl,gp) | (tpl,gp) <- zipEqual "mkTupleSelector" tpl_vs vars_s,
+ the_var `elem` gp ]
\end{code}
\begin{code}
mkNilExpr :: Type -> CoreExpr
-mkNilExpr ty = App (Var (dataConId nilDataCon)) (Type ty)
+mkNilExpr ty = mkConApp nilDataCon [Type ty]
mkConsExpr :: Type -> CoreExpr -> CoreExpr -> CoreExpr
-mkConsExpr ty hd tl = mkApps (Var (dataConId consDataCon)) [Type ty, hd, tl]
+mkConsExpr ty hd tl = mkConApp consDataCon [Type ty, hd, tl]
+
+mkListExpr :: Type -> [CoreExpr] -> CoreExpr
+mkListExpr ty xs = foldr (mkConsExpr ty) (mkNilExpr ty) xs
+
+
+-- The next three functions make tuple types, constructors and selectors,
+-- with the rule that a 1-tuple is represented by the thing itselg
+mkCoreTupTy :: [Type] -> Type
+mkCoreTupTy [ty] = ty
+mkCoreTupTy tys = mkTupleTy Boxed (length tys) tys
+
+mkCoreTup :: [CoreExpr] -> CoreExpr
+-- Builds exactly the specified tuple.
+-- No fancy business for big tuples
+mkCoreTup [] = Var unitDataConId
+mkCoreTup [c] = c
+mkCoreTup cs = mkConApp (tupleCon Boxed (length cs))
+ (map (Type . exprType) cs ++ cs)
+
+mkCoreSel :: [Id] -- The tuple args
+ -> Id -- The selected one
+ -> Id -- A variable of the same type as the scrutinee
+ -> CoreExpr -- Scrutinee
+ -> CoreExpr
+-- mkCoreSel [x,y,z] x v e
+-- ===> case e of v { (x,y,z) -> x
+mkCoreSel [var] should_be_the_same_var scrut_var scrut
+ = ASSERT(var == should_be_the_same_var)
+ scrut
+
+mkCoreSel vars the_var scrut_var scrut
+ = ASSERT( notNull vars )
+ Case scrut scrut_var
+ [(DataAlt (tupleCon Boxed (length vars)), vars, Var the_var)]
\end{code}