\begin{code}
module DsUtils (
- CanItFail(..), EquationInfo(..), MatchResult(..),
- EqnNo, EqnSet,
-
- tidyLitPat, tidyNPat,
+ EquationInfo(..),
+ firstPat, shiftEqns,
mkDsLet, mkDsLets,
- cantFailMatchResult, extractMatchResult,
- combineMatchResults,
- adjustMatchResult, adjustMatchResultDs,
- mkCoLetsMatchResult, mkGuardedMatchResult,
+ MatchResult(..), CanItFail(..),
+ cantFailMatchResult, alwaysFailMatchResult,
+ extractMatchResult, combineMatchResults,
+ adjustMatchResult, adjustMatchResultDs,
+ mkCoLetMatchResult,
+ mkGuardedMatchResult,
mkCoPrimCaseMatchResult, mkCoAlgCaseMatchResult,
+ wrapBind, wrapBinds,
- mkErrorAppDs, mkNilExpr, mkConsExpr,
- mkStringLit, mkStringLitFS, mkIntegerLit,
+ mkErrorAppDs, mkNilExpr, mkConsExpr, mkListExpr,
+ mkIntExpr, mkCharExpr,
+ mkStringExpr, mkStringExprFS, mkIntegerExpr,
- mkSelectorBinds, mkTupleExpr, mkTupleSelector,
+ mkSelectorBinds, mkTupleExpr, mkTupleSelector,
+ mkTupleType, mkTupleCase, mkBigCoreTup,
+ mkCoreTup, mkCoreTupTy,
+
+ dsReboundNames, lookupReboundName,
- selectMatchVar
+ selectSimpleMatchVarL, selectMatchVars
) 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 ( 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(..), inIntRange, tARGET_MAX_INT )
+import CoreUtils ( exprType, mkIfThenElse, mkCoerce, bindNonRec )
+import MkId ( iRREFUT_PAT_ERROR_ID, mkReboxingAlt, mkNewTypeBody )
+import Id ( idType, Id, mkWildId, mkTemplateLocals, mkSysLocal )
+import Var ( Var )
+import Name ( Name )
+import Literal ( Literal(..), mkStringLit, 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 )
+import DataCon ( DataCon, dataConSourceArity, dataConTyCon, dataConTag )
+import Type ( mkFunTy, isUnLiftedType, Type, splitTyConApp, mkTyVarTy )
+import TcType ( tcEqType )
+import TysPrim ( intPrimTy )
import TysWiredIn ( nilDataCon, consDataCon,
- tupleCon,
- stringTy,
+ tupleCon, mkTupleTy,
unitDataConId, unitTy,
charTy, charDataCon,
- intTy, intDataCon, smallIntegerDataCon,
- floatTy, floatDataCon,
- doubleTy, doubleDataCon,
- stringTy
- )
+ intTy, intDataCon,
+ isPArrFakeCon )
import BasicTypes ( Boxity(..) )
-import UniqSet ( mkUniqSet, minusUniqSet, isEmptyUniqSet, UniqSet )
-import Unique ( unpackCStringIdKey, unpackCStringUtf8IdKey,
- plusIntegerIdKey, timesIntegerIdKey )
+import UniqSet ( mkUniqSet, minusUniqSet, isEmptyUniqSet )
+import UniqSupply ( splitUniqSupply, uniqFromSupply, uniqsFromSupply )
+import PrelNames ( unpackCStringName, unpackCStringUtf8Name,
+ plusIntegerName, timesIntegerName, smallIntegerDataConName,
+ lengthPName, indexPName )
import Outputable
-import UnicodeUtil ( stringToUtf8 )
+import UnicodeUtil ( intsToUtf8 )
+import SrcLoc ( Located(..), unLoc )
+import Util ( isSingleton, notNull, zipEqual, sortWith )
+import ListSetOps ( assocDefault )
+import FastString
\end{code}
%************************************************************************
%* *
-\subsection{Tidying lit pats}
+ Rebindable syntax
%* *
%************************************************************************
\begin{code}
-tidyLitPat :: HsLit -> TypecheckedPat -> TypecheckedPat
-tidyLitPat (HsChar c) pat = ConPat charDataCon charTy [] [] [LitPat (HsCharPrim c) charPrimTy]
-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)
- -- 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
- | lit_ty == intTy = ConPat intDataCon lit_ty [] [] [LitPat (mk_int lit) intPrimTy]
- | lit_ty == floatTy = ConPat floatDataCon lit_ty [] [] [LitPat (mk_float lit) floatPrimTy]
- | lit_ty == doubleTy = ConPat doubleDataCon lit_ty [] [] [LitPat (mk_double lit) doublePrimTy]
- | 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 (HsInteger i) = HsIntPrim i
-
- mk_float (HsInteger i) = HsFloatPrim (fromInteger i)
- mk_float (HsRat f _) = HsFloatPrim f
-
- mk_double (HsInteger i) = HsDoublePrim (fromInteger i)
- mk_double (HsRat f _) = HsDoublePrim f
+ -- 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}
\begin{code}
mkDsLet :: CoreBind -> CoreExpr -> CoreExpr
mkDsLet (NonRec bndr rhs) body
- | isUnLiftedType (idType bndr) = Case rhs bndr [(DEFAULT,[],body)]
+ | isUnLiftedType (idType bndr)
+ = Case rhs bndr (exprType body) [(DEFAULT,[],body)]
mkDsLet bind body
= Let bind body
otherwise, make one up.
\begin{code}
-selectMatchVar :: TypecheckedPat -> DsM Id
-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...
+selectSimpleMatchVarL :: LPat Id -> DsM Id
+selectSimpleMatchVarL pat = selectMatchVar (unLoc pat) (hsPatType pat)
+
+-- (selectMatchVars ps tys) chooses variables of type tys
+-- to use for matching ps against. If the pattern is a variable,
+-- we try to use that, to save inventing lots of fresh variables.
+-- But even if it is a variable, its type might not match. Consider
+-- data T a where
+-- T1 :: Int -> T Int
+-- T2 :: a -> T a
+--
+-- f :: T a -> a -> Int
+-- f (T1 i) (x::Int) = x
+-- f (T2 i) (y::a) = 0
+-- Then we must not choose (x::Int) as the matching variable!
+
+selectMatchVars :: [Pat Id] -> [Type] -> DsM [Id]
+selectMatchVars [] [] = return []
+selectMatchVars (p:ps) (ty:tys) = do { v <- selectMatchVar p ty
+ ; vs <- selectMatchVars ps tys
+ ; return (v:vs) }
+
+selectMatchVar (LazyPat pat) pat_ty = selectMatchVar (unLoc pat) pat_ty
+selectMatchVar (VarPat var) pat_ty = try_for var pat_ty
+selectMatchVar (AsPat var pat) pat_ty = try_for (unLoc var) pat_ty
+selectMatchVar other_pat pat_ty = newSysLocalDs pat_ty -- OK, better make up one...
+
+try_for var pat_ty
+ | idType var `tcEqType` pat_ty = returnDs var
+ | otherwise = newSysLocalDs pat_ty
\end{code}
worthy of a type synonym and a few handy functions.
\begin{code}
+firstPat :: EquationInfo -> Pat Id
+firstPat eqn = head (eqn_pats eqn)
-type EqnNo = Int
-type EqnSet = UniqSet EqnNo
-
-data EquationInfo
- = EqnInfo
- EqnNo -- The number of the equation
-
- DsMatchContext -- The context info is used when producing warnings
- -- about shadowed patterns. It's the context
- -- of the *first* thing matched in this group.
- -- Should perhaps be a list of them all!
-
- [TypecheckedPat] -- The patterns for an eqn
-
- MatchResult -- Encapsulates the guards and bindings
-\end{code}
-
-\begin{code}
-data MatchResult
- = MatchResult
- CanItFail -- Tells whether the failure expression is used
- (CoreExpr -> DsM CoreExpr)
- -- Takes a expression to plug in at the
- -- failure point(s). The expression should
- -- be duplicatable!
-
-data CanItFail = CanFail | CantFail
-
-orFail CantFail CantFail = CantFail
-orFail _ _ = CanFail
+shiftEqns :: [EquationInfo] -> [EquationInfo]
+-- Drop the first pattern in each equation
+shiftEqns eqns = [ eqn { eqn_pats = tail (eqn_pats eqn) } | eqn <- eqns ]
\end{code}
Functions on MatchResults
\begin{code}
+alwaysFailMatchResult :: MatchResult
+alwaysFailMatchResult = MatchResult CanFail (\fail -> returnDs fail)
+
cantFailMatchResult :: CoreExpr -> MatchResult
cantFailMatchResult expr = MatchResult CantFail (\ ignore -> returnDs expr)
combineMatchResults match_result1@(MatchResult CantFail body_fn1) match_result2
= match_result1
-
adjustMatchResult :: (CoreExpr -> CoreExpr) -> MatchResult -> MatchResult
adjustMatchResult encl_fn (MatchResult can_it_fail body_fn)
= MatchResult can_it_fail (\fail -> body_fn fail `thenDs` \ body ->
= MatchResult can_it_fail (\fail -> body_fn fail `thenDs` \ body ->
encl_fn body)
+wrapBinds :: [(Var,Var)] -> CoreExpr -> CoreExpr
+wrapBinds [] e = e
+wrapBinds ((new,old):prs) e = wrapBind new old (wrapBinds prs e)
-mkCoLetsMatchResult :: [CoreBind] -> MatchResult -> MatchResult
-mkCoLetsMatchResult binds match_result
- = adjustMatchResult (mkDsLets binds) match_result
+wrapBind :: Var -> Var -> CoreExpr -> CoreExpr
+wrapBind new old body
+ | new==old = body
+ | isTyVar new = App (Lam new body) (Type (mkTyVarTy old))
+ | otherwise = Let (NonRec new (Var old)) body
+mkCoLetMatchResult :: CoreBind -> MatchResult -> MatchResult
+mkCoLetMatchResult bind match_result
+ = adjustMatchResult (mkDsLet bind) match_result
mkGuardedMatchResult :: CoreExpr -> MatchResult -> MatchResult
mkGuardedMatchResult pred_expr (MatchResult can_it_fail body_fn)
returnDs (mkIfThenElse pred_expr body fail))
mkCoPrimCaseMatchResult :: Id -- Scrutinee
+ -> Type -- Type of the case
-> [(Literal, MatchResult)] -- Alternatives
-> MatchResult
-mkCoPrimCaseMatchResult var match_alts
+mkCoPrimCaseMatchResult var ty match_alts
= MatchResult CanFail mk_case
where
mk_case fail
- = mapDs (mk_alt fail) match_alts `thenDs` \ alts ->
- returnDs (Case (Var var) var (alts ++ [(DEFAULT, [], fail)]))
+ = mappM (mk_alt fail) sorted_alts `thenDs` \ alts ->
+ returnDs (Case (Var var) var ty ((DEFAULT, [], fail) : alts))
+ sorted_alts = sortWith fst match_alts -- Right order for a Case
mk_alt fail (lit, MatchResult _ body_fn) = body_fn fail `thenDs` \ body ->
returnDs (LitAlt lit, [], body)
mkCoAlgCaseMatchResult :: Id -- Scrutinee
+ -> Type -- Type of exp
-> [(DataCon, [CoreBndr], MatchResult)] -- Alternatives
-> MatchResult
-
-mkCoAlgCaseMatchResult var match_alts
+mkCoAlgCaseMatchResult var ty 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_ids1) )
+ mkCoLetMatchResult (NonRec arg_id1 newtype_rhs) match_result1
+
+ | 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 = dataConTyCon con1
+ -- [Interesting: becuase of GADTs, we can't rely on the type of
+ -- the scrutinised Id to be sufficiently refined to have a TyCon in it]
-- 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)
-
+ (con1, arg_ids1, match_result1) = head match_alts
+ arg_id1 = head arg_ids1
+ newtype_rhs = mkNewTypeBody tycon (idType arg_id1) (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]
= CanFail
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))
+ sorted_alts = sortWith get_tag match_alts
+ get_tag (con, _, _) = dataConTag con
+ mk_case fail = mappM (mk_alt fail) sorted_alts `thenDs` \ alts ->
+ returnDs (Case (Var var) wild_var ty (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 ->
+ newUniqueSupply `thenDs` \ us ->
+ returnDs (mkReboxingAlt (uniqsFromSupply 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) ty [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 ->
+ mappM (mkAlt indexP) sorted_alts `thenDs` \alts ->
+ returnDs (DataAlt intDataCon, [l], (Case (Var l) wild ty (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}
-%
-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)
-\end{code}
+
%************************************************************************
%* *
-> DsM CoreExpr
mkErrorAppDs err_id ty msg
- = getSrcLocDs `thenDs` \ src_loc ->
+ = getSrcSpanDs `thenDs` \ src_loc ->
let
full_msg = showSDoc (hcat [ppr src_loc, text "|", text msg])
+ core_msg = Lit (mkStringLit full_msg)
in
- mkStringLit full_msg `thenDs` \ core_msg ->
- returnDs (mkApps (Var err_id) [(Type . unUsgTy) ty, core_msg])
- -- unUsgTy *required* -- KSW 1999-04-07
+ returnDs (mkApps (Var err_id) [Type ty, core_msg])
\end{code}
%************************************************************************
\begin{code}
-mkIntegerLit :: Integer -> DsM CoreExpr
-mkIntegerLit i
+mkCharExpr :: Char -> CoreExpr -- Returns C# c :: Int
+mkIntExpr :: Integer -> CoreExpr -- Returns I# i :: Int
+mkIntegerExpr :: Integer -> DsM CoreExpr -- Result :: Integer
+mkStringExpr :: String -> DsM CoreExpr -- Result :: String
+mkStringExprFS :: 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)
+ = dsLookupDataCon smallIntegerDataConName `thenDs` \ integer_dc ->
+ returnDs (mkSmallIntegerLit integer_dc 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
- = dsLookupGlobalValue plusIntegerIdKey `thenDs` \ plus_id ->
- dsLookupGlobalValue timesIntegerIdKey `thenDs` \ times_id ->
+ = dsLookupGlobalId plusIntegerName `thenDs` \ plus_id ->
+ dsLookupGlobalId timesIntegerName `thenDs` \ times_id ->
+ dsLookupDataCon smallIntegerDataConName `thenDs` \ integer_dc ->
let
+ lit i = mkSmallIntegerLit integer_dc i
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)
+ then lit i
+ else lit r `plus` lit (i-r)
+ | r == 0 = horner b q `times` lit b
+ | otherwise = lit r `plus` (horner b q `times` lit b)
where
(q,r) = i `quotRem` b
in
returnDs (horner tARGET_MAX_INT i)
-mkSmallIntegerLit i = mkConApp smallIntegerDataCon [mkIntLit i]
+mkSmallIntegerLit small_integer_data_con i = mkConApp small_integer_data_con [mkIntLit i]
-mkStringLit :: String -> DsM CoreExpr
-mkStringLit str = mkStringLitFS (_PK_ str)
+mkStringExpr str = mkStringExprFS (mkFastString str)
-mkStringLitFS :: FAST_STRING -> DsM CoreExpr
-mkStringLitFS str
- | _NULL_ str
+mkStringExprFS 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 (headFS str)
in
returnDs (mkConsExpr charTy the_char (mkNilExpr charTy))
- | all safeChar chars
- = dsLookupGlobalValue unpackCStringIdKey `thenDs` \ unpack_id ->
+ | all safeChar int_chars
+ = dsLookupGlobalId unpackCStringName `thenDs` \ unpack_id ->
returnDs (App (Var unpack_id) (Lit (MachStr str)))
| otherwise
- = dsLookupGlobalValue unpackCStringUtf8IdKey `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}
expressions.
\begin{code}
-mkSelectorBinds :: TypecheckedPat -- The pattern
- -> CoreExpr -- Expression to which the pattern is bound
+mkSelectorBinds :: LPat Id -- The pattern
+ -> CoreExpr -- Expression to which the pattern is bound
-> DsM [(Id,CoreExpr)]
-mkSelectorBinds (VarPat v) val_expr
+mkSelectorBinds (L _ (VarPat v)) val_expr
= 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_lpat 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 PredType, 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 ->
+ mappM (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_lpat p = is_simple_pat (unLoc p)
+
+ is_simple_pat (TuplePat ps Boxed) = all is_triv_lpat ps
+ is_simple_pat (ConPatOut _ _ _ _ ps _) = all is_triv_lpat (hsConArgs ps)
+ is_simple_pat (VarPat _) = True
+ is_simple_pat (ParPat p) = is_simple_lpat p
+ is_simple_pat other = False
- 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_triv_lpat p = is_triv_pat (unLoc p)
is_triv_pat (VarPat v) = True
is_triv_pat (WildPat _) = True
+ is_triv_pat (ParPat p) = is_triv_lpat 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 ids = mkBigCoreTup (map Var ids)
+
+-- corresponding type
+mkTupleType :: [Id] -> Type
+mkTupleType ids = mkBigTuple mkCoreTupTy (map idType ids)
-mkTupleExpr [] = Var unitDataConId
-mkTupleExpr [id] = Var id
-mkTupleExpr ids = mkConApp (tupleCon Boxed (length ids))
- (map (Type . unUsgTy . idType) ids ++ [ Var i | i <- ids ])
+mkBigCoreTup :: [CoreExpr] -> CoreExpr
+mkBigCoreTup = mkBigTuple mkCoreTup
+
+mkBigTuple :: ([a] -> a) -> [a] -> a
+mkBigTuple small_tuple as = mk_big_tuple (chunkify as)
+ where
+ -- Each sub-list is short enough to fit in a tuple
+ mk_big_tuple [as] = small_tuple as
+ mk_big_tuple as_s = mk_big_tuple (chunkify (map small_tuple as_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}
+
+A generalization of @mkTupleSelector@, allowing the body
+of the case to be an arbitrary expression.
+
+If the tuple is big, it is nested:
+
+ mkTupleCase uniqs [a,b,c,d] body v e
+ = case e of v { (p,q) ->
+ case p of p { (a,b) ->
+ case q of q { (c,d) ->
+ body }}}
+
+To avoid shadowing, we use uniqs to invent new variables p,q.
+
+ToDo: eliminate cases where none of the variables are needed.
+
+\begin{code}
+mkTupleCase
+ :: UniqSupply -- for inventing names of intermediate variables
+ -> [Id] -- the tuple args
+ -> CoreExpr -- body of the case
+ -> Id -- a variable of the same type as the scrutinee
+ -> CoreExpr -- scrutinee
+ -> CoreExpr
+
+mkTupleCase uniqs vars body scrut_var scrut
+ = mk_tuple_case uniqs (chunkify vars) body
+ where
+ mk_tuple_case us [vars] body
+ = mkSmallTupleCase vars body scrut_var scrut
+ mk_tuple_case us vars_s body
+ = let
+ (us', vars', body') = foldr one_tuple_case (us, [], body) vars_s
+ in
+ mk_tuple_case us' (chunkify vars') body'
+ one_tuple_case chunk_vars (us, vs, body)
+ = let
+ (us1, us2) = splitUniqSupply us
+ scrut_var = mkSysLocal FSLIT("ds") (uniqFromSupply us1)
+ (mkCoreTupTy (map idType chunk_vars))
+ body' = mkSmallTupleCase chunk_vars body scrut_var (Var scrut_var)
+ in (us2, scrut_var:vs, body')
\end{code}
+The same, but with a tuple small enough not to need nesting.
+
+\begin{code}
+mkSmallTupleCase
+ :: [Id] -- the tuple args
+ -> CoreExpr -- body of the case
+ -> Id -- a variable of the same type as the scrutinee
+ -> CoreExpr -- scrutinee
+ -> CoreExpr
+
+mkSmallTupleCase [var] body _scrut_var scrut
+ = bindNonRec var scrut body
+mkSmallTupleCase vars body scrut_var scrut
+-- One branch no refinement?
+ = Case scrut scrut_var (exprType body) [(DataAlt (tupleCon Boxed (length vars)), vars, body)]
+\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 (idType the_var)
+ [(DataAlt (tupleCon Boxed (length vars)), vars, Var the_var)]
\end{code}
\end{code}
-
projects / ghc-hetmet.git / blobdiff