CanItFail(..), EquationInfo(..), MatchResult(..),
EqnNo, EqnSet,
- tidyLitPat,
+ tidyLitPat, tidyNPat,
mkDsLet, mkDsLets,
mkCoLetsMatchResult, mkGuardedMatchResult,
mkCoPrimCaseMatchResult, mkCoAlgCaseMatchResult,
- mkErrorAppDs, mkNilExpr, mkConsExpr,
- mkStringLit, mkStringLitFS,
+ mkErrorAppDs, mkNilExpr, mkConsExpr, mkListExpr,
+ mkIntExpr, mkCharExpr,
+ mkStringLit, mkStringLitFS, mkIntegerExpr,
- mkSelectorBinds, mkTupleExpr, mkTupleSelector,
+ mkSelectorBinds, mkTupleExpr, mkTupleSelector,
+ mkCoreTup, mkCoreSel, mkCoreTupTy,
+
+ dsReboundNames, lookupReboundName,
selectMatchVar
) where
#include "HsVersions.h"
-import {-# SOURCE #-} Match ( matchSimply )
+import {-# SOURCE #-} Match ( matchSimply )
+import {-# SOURCE #-} DsExpr( dsExpr )
import HsSyn
-import TcHsSyn ( TypecheckedPat )
-import DsHsSyn ( 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 Id ( idType, Id, mkWildId )
-import Literal ( Literal(..) )
+import CoreUtils ( exprType, mkIfThenElse, mkCoerce )
+import MkId ( iRREFUT_PAT_ERROR_ID, mkReboxingAlt, mkNewTypeBody )
+import Id ( idType, Id, mkWildId, mkTemplateLocals )
+import Name ( Name )
+import Literal ( Literal(..), inIntRange, tARGET_MAX_INT )
import TyCon ( isNewTyCon, tyConDataCons )
-import DataCon ( DataCon, StrictnessMark, maybeMarkedUnboxed,
- dataConStrictMarks, dataConId, splitProductType_maybe
- )
-import Type ( mkFunTy, isUnLiftedType, splitAlgTyConApp, unUsgTy,
- Type
- )
-import TysPrim ( intPrimTy,
- charPrimTy,
- floatPrimTy,
- doublePrimTy,
- addrPrimTy,
- wordPrimTy
- )
+import DataCon ( DataCon, dataConSourceArity )
+import Type ( mkFunTy, isUnLiftedType, Type, splitTyConApp )
+import TcType ( tcTyConAppTyCon, isIntTy, isFloatTy, isDoubleTy )
+import TysPrim ( intPrimTy )
import TysWiredIn ( nilDataCon, consDataCon,
- tupleCon,
- stringTy,
+ tupleCon, mkTupleTy,
unitDataConId, unitTy,
charTy, charDataCon,
- intTy, intDataCon,
- floatTy, floatDataCon,
- doubleTy, doubleDataCon,
- addrTy, addrDataCon,
- wordTy, wordDataCon
- )
+ intTy, intDataCon, smallIntegerDataCon,
+ floatDataCon,
+ doubleDataCon,
+ stringTy, isPArrFakeCon )
import BasicTypes ( Boxity(..) )
import UniqSet ( mkUniqSet, minusUniqSet, isEmptyUniqSet, UniqSet )
-import Unique ( unpackCStringIdKey, unpackCString2IdKey )
+import PrelNames ( unpackCStringName, unpackCStringUtf8Name,
+ plusIntegerName, timesIntegerName,
+ lengthPName, indexPName )
import Outputable
+import UnicodeUtil ( intsToUtf8, stringToUtf8 )
+import Util ( isSingleton, notNull, zipEqual )
+import ListSetOps ( assocDefault )
+import FastString
\end{code}
%************************************************************************
%* *
-\subsection{Tidying lit pats}
+ Rebindable syntax
%* *
%************************************************************************
\begin{code}
-tidyLitPat lit lit_ty default_pat
- | lit_ty == charTy = ConPat charDataCon lit_ty [] [] [LitPat (mk_char lit) charPrimTy]
- | lit_ty == intTy = ConPat intDataCon lit_ty [] [] [LitPat (mk_int lit) intPrimTy]
- | lit_ty == wordTy = ConPat wordDataCon lit_ty [] [] [LitPat (mk_word lit) wordPrimTy]
- | lit_ty == addrTy = ConPat addrDataCon lit_ty [] [] [LitPat (mk_addr lit) addrPrimTy]
- | lit_ty == floatTy = ConPat floatDataCon lit_ty [] [] [LitPat (mk_float lit) floatPrimTy]
- | lit_ty == doubleTy = ConPat doubleDataCon lit_ty [] [] [LitPat (mk_double lit) doublePrimTy]
-
- -- Convert literal patterns like "foo" to 'f':'o':'o':[]
- | str_lit lit = mk_list lit
-
- | otherwise = default_pat
+dsReboundNames :: ReboundNames Id
+ -> DsM ([CoreBind], -- Auxiliary bindings
+ [(Name,Id)]) -- Maps the standard name to its value
+dsReboundNames rebound_ids
+ = mapAndUnzipDs mk_bind rebound_ids `thenDs` \ (binds_s, prs) ->
+ return (concat binds_s, prs)
where
- mk_int (HsInt i) = HsIntPrim i
- mk_int l@(HsLitLit s) = l
-
- mk_char (HsChar c) = HsCharPrim c
- mk_char l@(HsLitLit s) = l
-
- mk_word l@(HsLitLit s) = l
+ -- The cheapo special case can happen when we
+ -- make an intermediate HsDo when desugaring a RecStmt
+ mk_bind (std_name, HsVar id) = return ([], (std_name, id))
+ mk_bind (std_name, expr) = dsExpr expr `thenDs` \ rhs ->
+ newSysLocalDs (exprType rhs) `thenDs` \ id ->
+ return ([NonRec id rhs], (std_name, id))
+
+lookupReboundName :: [(Name,Id)] -> Name -> CoreExpr
+lookupReboundName prs std_name
+ = Var (assocDefault (mk_panic std_name) prs std_name)
+ where
+ mk_panic std_name = pprPanic "dsReboundNames" (ptext SLIT("Not found:") <+> ppr std_name)
+\end{code}
- mk_addr l@(HsLitLit s) = l
- mk_float (HsInt i) = HsFloatPrim (fromInteger i)
- mk_float (HsFrac f) = HsFloatPrim f
- mk_float l@(HsLitLit s) = l
+%************************************************************************
+%* *
+\subsection{Tidying lit pats}
+%* *
+%************************************************************************
- mk_double (HsInt i) = HsDoublePrim (fromInteger i)
- mk_double (HsFrac f) = HsDoublePrim f
- mk_double l@(HsLitLit s) = l
+\begin{code}
+tidyLitPat :: HsLit -> TypecheckedPat -> TypecheckedPat
+tidyLitPat (HsChar c) pat = mkCharLitPat c
+tidyLitPat lit pat = pat
+
+tidyNPat :: HsLit -> Type -> TypecheckedPat -> TypecheckedPat
+tidyNPat (HsString s) _ pat
+ | 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
- null_str_lit (HsString s) = _NULL_ s
- null_str_lit other_lit = False
+tidyNPat lit lit_ty default_pat
+ | 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
- str_lit (HsString s) = True
- str_lit _ = False
+ where
+ mk_int (HsInteger i) = HsIntPrim i
- mk_list (HsString s) = foldr
- (\c pat -> ConPat consDataCon lit_ty [] [] [mk_char_lit c,pat])
- (ConPat nilDataCon lit_ty [] [] []) (_UNPK_ s)
+ mk_float (HsInteger i) = HsFloatPrim (fromInteger i)
+ mk_float (HsRat f _) = HsFloatPrim f
- mk_char_lit c = ConPat charDataCon charTy [] [] [LitPat (HsCharPrim c) charPrimTy]
+ mk_double (HsInteger i) = HsDoublePrim (fromInteger i)
+ mk_double (HsRat f _) = HsDoublePrim f
\end{code}
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}
where
mk_case fail
= mapDs (mk_alt fail) match_alts `thenDs` \ alts ->
- returnDs (Case (Var var) var (alts ++ [(DEFAULT, [], fail)]))
+ returnDs (Case (Var var) var ((DEFAULT, [], fail) : alts))
mk_alt fail (lit, MatchResult _ body_fn) = body_fn fail `thenDs` \ body ->
returnDs (LitAlt lit, [], body)
mkCoAlgCaseMatchResult var match_alts
| isNewTyCon tycon -- Newtype case; use a let
- = ASSERT( newtype_sanity )
- mkCoLetsMatchResult [coercion_bind] match_result
+ = 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
-- Common stuff
scrut_ty = idType var
- (tycon, _, _) = splitAlgTyConApp scrut_ty
+ tycon = tcTyConAppTyCon scrut_ty -- Newtypes must be opaque here
-- Stuff for newtype
(_, arg_ids, match_result) = head match_alts
- arg_id = head arg_ids
- coercion_bind = NonRec arg_id (Note (Coerce (unUsgTy (idType arg_id))
- (unUsgTy scrut_ty))
- (Var var))
- newtype_sanity = null (tail match_alts) && null (tail arg_ids)
-
+ arg_id = head arg_ids
+ 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]
wild_var = mkWildId (idType var)
mk_case fail = mapDs (mk_alt fail) match_alts `thenDs` \ alts ->
- returnDs (Case (Var var) wild_var (alts ++ mk_default fail))
+ returnDs (Case (Var var) wild_var (mk_default fail ++ alts))
mk_alt fail (con, args, MatchResult _ body_fn)
- = body_fn fail `thenDs` \ body ->
- rebuildConArgs con args (dataConStrictMarks con) body
- `thenDs` \ (body', real_args) ->
- returnDs (DataAlt con, real_args, 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
-\end{code}
-%
-For each constructor we match on, we might need to re-pack some
-of the strict fields if they are unpacked in the constructor.
-%
-\begin{code}
-rebuildConArgs
- :: DataCon -- the con we're matching on
- -> [Id] -- the source-level args
- -> [StrictnessMark] -- the strictness annotations (per-arg)
- -> CoreExpr -- the body
- -> DsM (CoreExpr, [Id])
-
-rebuildConArgs con [] stricts body = returnDs (body, [])
-rebuildConArgs con (arg:args) stricts body | isTyVar arg
- = rebuildConArgs con args stricts body `thenDs` \ (body', args') ->
- returnDs (body',arg:args')
-rebuildConArgs con (arg:args) (str:stricts) body
- = rebuildConArgs con args stricts body `thenDs` \ (body', real_args) ->
- case maybeMarkedUnboxed str of
- Just (pack_con1, _) ->
- case splitProductType_maybe (idType arg) of
- Just (_, tycon_args, pack_con, con_arg_tys) ->
- ASSERT( pack_con == pack_con1 )
- newSysLocalsDs con_arg_tys `thenDs` \ unpacked_args ->
- returnDs (
- mkDsLet (NonRec arg (mkConApp pack_con
- (map Type tycon_args ++
- map Var unpacked_args))) body',
- unpacked_args ++ real_args
- )
-
- _ -> returnDs (body', arg:real_args)
+
+ -- 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}
+
%************************************************************************
%* *
\subsection{Desugarer's versions of some Core functions}
= getSrcLocDs `thenDs` \ src_loc ->
let
full_msg = showSDoc (hcat [ppr src_loc, text "|", text msg])
+ core_msg = Lit (MachStr (mkFastString (stringToUtf8 full_msg)))
+ in
+ returnDs (mkApps (Var err_id) [Type ty, core_msg])
+\end{code}
+
+
+*************************************************************
+%* *
+\subsection{Making literals}
+%* *
+%************************************************************************
+
+\begin{code}
+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)
+
+-- Special case for integral literals with a large magnitude:
+-- They are transformed into an expression involving only smaller
+-- integral literals. This improves constant folding.
+
+ | otherwise -- Big, so start from a string
+ = 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
+
+ -- Transform i into (x1 + (x2 + (x3 + (...) * b) * b) * b) with abs xi <= b
+ horner :: Integer -> Integer -> CoreExpr
+ horner b i | abs q <= 1 = if r == 0 || r == i
+ then mkSmallIntegerLit i
+ else mkSmallIntegerLit r `plus` mkSmallIntegerLit (i-r)
+ | r == 0 = horner b q `times` mkSmallIntegerLit b
+ | otherwise = mkSmallIntegerLit r `plus` (horner b q `times` mkSmallIntegerLit b)
+ where
+ (q,r) = i `quotRem` b
+
in
- mkStringLit full_msg `thenDs` \ core_msg ->
- returnDs (mkApps (Var err_id) [(Type . unUsgTy) ty, core_msg])
- -- unUsgTy *required* -- KSW 1999-04-07
+ returnDs (horner tARGET_MAX_INT i)
-mkStringLit :: String -> DsM CoreExpr
-mkStringLit str = mkStringLitFS (_PK_ str)
+mkSmallIntegerLit i = mkConApp smallIntegerDataCon [mkIntLit i]
+
+mkStringLit str = mkStringLitFS (mkFastString str)
-mkStringLitFS :: FAST_STRING -> DsM CoreExpr
mkStringLitFS str
- | any is_NUL (_UNPK_ str)
- = -- Must cater for NULs in literal string
- dsLookupGlobalValue unpackCString2IdKey `thenDs` \ unpack_id ->
- returnDs (mkApps (Var unpack_id)
- [Lit (MachStr str),
- mkIntLitInt (_LENGTH_ str)])
+ | nullFastString str
+ = returnDs (mkNilExpr charTy)
- | otherwise
- = -- No NULs in the string
- dsLookupGlobalValue unpackCStringIdKey `thenDs` \ unpack_id ->
+ | lengthFS str == 1
+ = let
+ the_char = mkCharExpr (headIntFS str)
+ in
+ returnDs (mkConsExpr charTy the_char (mkNilExpr charTy))
+
+ | all safeChar int_chars
+ = dsLookupGlobalId unpackCStringName `thenDs` \ unpack_id ->
returnDs (App (Var unpack_id) (Lit (MachStr str)))
+ | otherwise
+ = dsLookupGlobalId unpackCStringUtf8Name `thenDs` \ unpack_id ->
+ returnDs (App (Var unpack_id) (Lit (MachStr (mkFastString (intsToUtf8 int_chars)))))
+
where
- is_NUL c = c == '\0'
+ int_chars = unpackIntFS str
+ safeChar c = c >= 1 && c <= 0xFF
\end{code}
+
%************************************************************************
%* *
\subsection[mkSelectorBind]{Make a selector bind}
= returnDs [(v, val_expr)]
mkSelectorBinds pat val_expr
- | length binders == 1 || 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 ->
+ | isSingleton binders || is_simple_pat pat
+ = -- 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 LetMatch 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) LetMatch pat
+ = 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. Notice we must
-throw out any usage annotation on the outside of an Id.
+%************************************************************************
+%* *
+ 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 . unUsgTy . 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}
\end{code}
-
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