X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FdeSugar%2FDsUtils.lhs;h=cf670cdf3790b29ad3792265e7568a53da5734da;hp=209a0949bfc236f6a8f1fbb0b8d8386eb10f5d99;hb=4c6a3f787abcaed009a574196d82237d9ae64fc8;hpb=7eb8be6b5fcd80c4d9dfde6990dcb9fec4062d6b diff --git a/compiler/deSugar/DsUtils.lhs b/compiler/deSugar/DsUtils.lhs index 209a094..cf670cd 100644 --- a/compiler/deSugar/DsUtils.lhs +++ b/compiler/deSugar/DsUtils.lhs @@ -8,17 +8,18 @@ Utilities for desugaring This module exports some utility functions of no great interest. \begin{code} + module DsUtils ( EquationInfo(..), firstPat, shiftEqns, - mkDsLet, mkDsLets, + mkDsLet, mkDsLets, mkDsApp, mkDsApps, MatchResult(..), CanItFail(..), cantFailMatchResult, alwaysFailMatchResult, extractMatchResult, combineMatchResults, adjustMatchResult, adjustMatchResultDs, - mkCoLetMatchResult, mkGuardedMatchResult, + mkCoLetMatchResult, mkViewMatchResult, mkGuardedMatchResult, matchCanFail, mkEvalMatchResult, mkCoPrimCaseMatchResult, mkCoAlgCaseMatchResult, wrapBind, wrapBinds, @@ -26,10 +27,21 @@ module DsUtils ( mkErrorAppDs, mkNilExpr, mkConsExpr, mkListExpr, mkIntExpr, mkCharExpr, mkStringExpr, mkStringExprFS, mkIntegerExpr, + mkBuildExpr, mkFoldrExpr, - mkSelectorBinds, mkTupleExpr, mkTupleSelector, - mkTupleType, mkTupleCase, mkBigCoreTup, - mkCoreTup, mkCoreTupTy, seqVar, + seqVar, + + -- Core tuples + mkCoreVarTup, mkCoreTup, mkCoreVarTupTy, mkCoreTupTy, + mkBigCoreVarTup, mkBigCoreTup, mkBigCoreVarTupTy, mkBigCoreTupTy, + + -- LHs tuples + mkLHsVarTup, mkLHsTup, mkLHsVarPatTup, mkLHsPatTup, + mkBigLHsVarTup, mkBigLHsTup, mkBigLHsVarPatTup, mkBigLHsPatTup, + + -- Tuple bindings + mkSelectorBinds, mkTupleSelector, + mkSmallTupleCase, mkTupleCase, dsSyntaxTable, lookupEvidence, @@ -69,12 +81,11 @@ import SrcLoc import Util import ListSetOps import FastString +import StaticFlags + import Data.Char -import DynFlags -#ifdef DEBUG -import Util -#endif +infixl 4 `mkDsApp`, `mkDsApps` \end{code} @@ -90,17 +101,17 @@ dsSyntaxTable :: SyntaxTable Id -> DsM ([CoreBind], -- Auxiliary bindings [(Name,Id)]) -- Maps the standard name to its value -dsSyntaxTable rebound_ids - = mapAndUnzipDs mk_bind rebound_ids `thenDs` \ (binds_s, prs) -> +dsSyntaxTable rebound_ids = do + (binds_s, prs) <- mapAndUnzipM mk_bind rebound_ids return (concat binds_s, prs) where - -- The cheapo special case can happen when we - -- make an intermediate HsDo when desugaring a RecStmt + -- 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)) + mk_bind (std_name, expr) = do + rhs <- dsExpr expr + id <- newSysLocalDs (exprType rhs) + return ([NonRec id rhs], (std_name, id)) lookupEvidence :: [(Name, Id)] -> Name -> Id lookupEvidence prs std_name @@ -121,16 +132,72 @@ back again. \begin{code} mkDsLet :: CoreBind -> CoreExpr -> CoreExpr -mkDsLet (NonRec bndr rhs) body - | isUnLiftedType (idType bndr) +mkDsLet (NonRec bndr rhs) body -- See Note [CoreSyn let/app invariant] + | isUnLiftedType (idType bndr) && not (exprOkForSpeculation rhs) = Case rhs bndr (exprType body) [(DEFAULT,[],body)] mkDsLet bind body = Let bind body mkDsLets :: [CoreBind] -> CoreExpr -> CoreExpr mkDsLets binds body = foldr mkDsLet body binds + +----------- +mkDsApp :: CoreExpr -> CoreExpr -> CoreExpr +-- Check the invariant that the arg of an App is ok-for-speculation if unlifted +-- See CoreSyn Note [CoreSyn let/app invariant] +mkDsApp fun (Type ty) = App fun (Type ty) +mkDsApp fun arg = mk_val_app fun arg arg_ty res_ty + where + (arg_ty, res_ty) = splitFunTy (exprType fun) + +----------- +mkDsApps :: CoreExpr -> [CoreExpr] -> CoreExpr +-- Slightly more efficient version of (foldl mkDsApp) +mkDsApps fun args + = go fun (exprType fun) args + where + go fun _ [] = fun + go fun fun_ty (Type ty : args) = go (App fun (Type ty)) (applyTy fun_ty ty) args + go fun fun_ty (arg : args) = go (mk_val_app fun arg arg_ty res_ty) res_ty args + where + (arg_ty, res_ty) = splitFunTy fun_ty +----------- +mk_val_app :: CoreExpr -> CoreExpr -> Type -> Type -> CoreExpr +mk_val_app fun arg arg_ty _ -- See Note [CoreSyn let/app invariant] + | not (isUnLiftedType arg_ty) || exprOkForSpeculation arg + = App fun arg -- The vastly common case + +mk_val_app (Var f `App` Type ty1 `App` Type _ `App` arg1) arg2 _ res_ty + | f == seqId -- Note [Desugaring seq] + = Case arg1 (mkWildId ty1) res_ty [(DEFAULT,[],arg2)] + +mk_val_app fun arg arg_ty res_ty + = Case arg (mkWildId arg_ty) res_ty [(DEFAULT,[],App fun (Var arg_id))] + where + arg_id = mkWildId arg_ty -- Lots of shadowing, but it doesn't matter, + -- because 'fun ' should not have a free wild-id \end{code} +Note [Desugaring seq] cf Trac #1031 +~~~~~~~~~~~~~~~~~~~~~ + f x y = x `seq` (y `seq` (# x,y #)) + +The [CoreSyn let/app invariant] means that, other things being equal, because +the argument to the outer 'seq' has an unlifted type, we'll use call-by-value thus: + + f x y = case (y `seq` (# x,y #)) of v -> x `seq` v + +But that is bad for two reasons: + (a) we now evaluate y before x, and + (b) we can't bind v to an unboxed pair + +Seq is very, very special! So we recognise it right here, and desugar to + case x of _ -> case y of _ -> (# x,y #) + +The special case would be valid for all calls to 'seq', but it's only *necessary* +for ones whose second argument has an unlifted type. So we only catch the latter +case here, to avoid unnecessary tests. + %************************************************************************ %* * @@ -166,11 +233,12 @@ selectSimpleMatchVarL pat = selectMatchVar (unLoc pat) selectMatchVars :: [Pat Id] -> DsM [Id] selectMatchVars ps = mapM selectMatchVar ps +selectMatchVar :: Pat Id -> DsM Id selectMatchVar (BangPat pat) = selectMatchVar (unLoc pat) selectMatchVar (LazyPat pat) = selectMatchVar (unLoc pat) selectMatchVar (ParPat pat) = selectMatchVar (unLoc pat) selectMatchVar (VarPat var) = return var -selectMatchVar (AsPat var pat) = return (unLoc var) +selectMatchVar (AsPat var _) = return (unLoc var) selectMatchVar other_pat = newSysLocalDs (hsPatType other_pat) -- OK, better make up one... \end{code} @@ -188,7 +256,7 @@ worthy of a type synonym and a few handy functions. \begin{code} firstPat :: EquationInfo -> Pat Id -firstPat eqn = head (eqn_pats eqn) +firstPat eqn = ASSERT( notNull (eqn_pats eqn) ) head (eqn_pats eqn) shiftEqns :: [EquationInfo] -> [EquationInfo] -- Drop the first pattern in each equation @@ -203,43 +271,41 @@ matchCanFail (MatchResult CanFail _) = True matchCanFail (MatchResult CantFail _) = False alwaysFailMatchResult :: MatchResult -alwaysFailMatchResult = MatchResult CanFail (\fail -> returnDs fail) +alwaysFailMatchResult = MatchResult CanFail (\fail -> return fail) cantFailMatchResult :: CoreExpr -> MatchResult -cantFailMatchResult expr = MatchResult CantFail (\ ignore -> returnDs expr) +cantFailMatchResult expr = MatchResult CantFail (\_ -> return expr) extractMatchResult :: MatchResult -> CoreExpr -> DsM CoreExpr -extractMatchResult (MatchResult CantFail match_fn) fail_expr +extractMatchResult (MatchResult CantFail match_fn) _ = match_fn (error "It can't fail!") -extractMatchResult (MatchResult CanFail match_fn) fail_expr - = mkFailurePair fail_expr `thenDs` \ (fail_bind, if_it_fails) -> - match_fn if_it_fails `thenDs` \ body -> - returnDs (mkDsLet fail_bind body) +extractMatchResult (MatchResult CanFail match_fn) fail_expr = do + (fail_bind, if_it_fails) <- mkFailurePair fail_expr + body <- match_fn if_it_fails + return (mkDsLet fail_bind body) combineMatchResults :: MatchResult -> MatchResult -> MatchResult combineMatchResults (MatchResult CanFail body_fn1) - (MatchResult can_it_fail2 body_fn2) + (MatchResult can_it_fail2 body_fn2) = MatchResult can_it_fail2 body_fn where - body_fn fail = body_fn2 fail `thenDs` \ body2 -> - mkFailurePair body2 `thenDs` \ (fail_bind, duplicatable_expr) -> - body_fn1 duplicatable_expr `thenDs` \ body1 -> - returnDs (Let fail_bind body1) + body_fn fail = do body2 <- body_fn2 fail + (fail_bind, duplicatable_expr) <- mkFailurePair body2 + body1 <- body_fn1 duplicatable_expr + return (Let fail_bind body1) -combineMatchResults match_result1@(MatchResult CantFail body_fn1) match_result2 +combineMatchResults match_result1@(MatchResult CantFail _) _ = match_result1 adjustMatchResult :: DsWrapper -> MatchResult -> MatchResult adjustMatchResult encl_fn (MatchResult can_it_fail body_fn) - = MatchResult can_it_fail (\fail -> body_fn fail `thenDs` \ body -> - returnDs (encl_fn body)) + = MatchResult can_it_fail (\fail -> encl_fn <$> body_fn fail) adjustMatchResultDs :: (CoreExpr -> DsM CoreExpr) -> MatchResult -> MatchResult adjustMatchResultDs encl_fn (MatchResult can_it_fail body_fn) - = MatchResult can_it_fail (\fail -> body_fn fail `thenDs` \ body -> - encl_fn body) + = MatchResult can_it_fail (\fail -> encl_fn =<< body_fn fail) wrapBinds :: [(Var,Var)] -> CoreExpr -> CoreExpr wrapBinds [] e = e @@ -258,14 +324,20 @@ seqVar var body = Case (Var var) var (exprType body) mkCoLetMatchResult :: CoreBind -> MatchResult -> MatchResult mkCoLetMatchResult bind = adjustMatchResult (mkDsLet bind) +-- (mkViewMatchResult var' viewExpr var mr) makes the expression +-- let var' = viewExpr var in mr +mkViewMatchResult :: Id -> CoreExpr -> Id -> MatchResult -> MatchResult +mkViewMatchResult var' viewExpr var = + adjustMatchResult (mkDsLet (NonRec var' (mkDsApp viewExpr (Var var)))) + mkEvalMatchResult :: Id -> Type -> MatchResult -> MatchResult mkEvalMatchResult var ty = adjustMatchResult (\e -> Case (Var var) var ty [(DEFAULT, [], e)]) mkGuardedMatchResult :: CoreExpr -> MatchResult -> MatchResult -mkGuardedMatchResult pred_expr (MatchResult can_it_fail body_fn) - = MatchResult CanFail (\fail -> body_fn fail `thenDs` \ body -> - returnDs (mkIfThenElse pred_expr body fail)) +mkGuardedMatchResult pred_expr (MatchResult _ body_fn) + = MatchResult CanFail (\fail -> do body <- body_fn fail + return (mkIfThenElse pred_expr body fail)) mkCoPrimCaseMatchResult :: Id -- Scrutinee -> Type -- Type of the case @@ -274,13 +346,13 @@ mkCoPrimCaseMatchResult :: Id -- Scrutinee mkCoPrimCaseMatchResult var ty match_alts = MatchResult CanFail mk_case where - mk_case fail - = mappM (mk_alt fail) sorted_alts `thenDs` \ alts -> - returnDs (Case (Var var) var ty ((DEFAULT, [], fail) : alts)) + mk_case fail = do + alts <- mapM (mk_alt fail) sorted_alts + return (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) + mk_alt fail (lit, MatchResult _ body_fn) = do body <- body_fn fail + return (LitAlt lit, [], body) mkCoAlgCaseMatchResult :: Id -- Scrutinee @@ -303,8 +375,8 @@ mkCoAlgCaseMatchResult var ty match_alts -- the scrutinised Id to be sufficiently refined to have a TyCon in it] -- Stuff for newtype - (con1, arg_ids1, match_result1) = head match_alts - arg_id1 = head arg_ids1 + (con1, arg_ids1, match_result1) = ASSERT( notNull match_alts ) head match_alts + arg_id1 = ASSERT( notNull arg_ids1 ) head arg_ids1 var_ty = idType var (tc, ty_args) = splitNewTyConApp var_ty newtype_rhs = unwrapNewTypeBody tc ty_args (Var var) @@ -321,13 +393,13 @@ mkCoAlgCaseMatchResult var ty match_alts wild_var = mkWildId (idType var) 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_case fail = do alts <- mapM (mk_alt fail) sorted_alts + return (Case (Var var) wild_var ty (mk_default fail ++ alts)) - mk_alt fail (con, args, MatchResult _ body_fn) - = body_fn fail `thenDs` \ body -> - newUniqueSupply `thenDs` \ us -> - returnDs (mkReboxingAlt (uniqsFromSupply us) con args body) + mk_alt fail (con, args, MatchResult _ body_fn) = do + body <- body_fn fail + us <- newUniqueSupply + return (mkReboxingAlt (uniqsFromSupply us) con args body) mk_default fail | exhaustive_case = [] | otherwise = [(DEFAULT, [], fail)] @@ -363,13 +435,13 @@ mkCoAlgCaseMatchResult var ty match_alts case (isPArrFakeCon dcon, isPArrFakeAlts alts) of (True , True ) -> True (False, False) -> False - _ -> - panic "DsUtils: You may not mix `[:...:]' with `PArr' patterns" + _ -> panic "DsUtils: you may not mix `[:...:]' with `PArr' patterns" + isPArrFakeAlts [] = panic "DsUtils: unexpectedly found an empty list of PArr fake alternatives" -- - mk_parrCase fail = - dsLookupGlobalId lengthPName `thenDs` \lengthP -> - unboxAlt `thenDs` \alt -> - returnDs (Case (len lengthP) (mkWildId intTy) ty [alt]) + mk_parrCase fail = do + lengthP <- dsLookupGlobalId lengthPName + alt <- unboxAlt + return (Case (len lengthP) (mkWildId intTy) ty [alt]) where elemTy = case splitTyConApp (idType var) of (_, [elemTy]) -> elemTy @@ -377,11 +449,11 @@ mkCoAlgCaseMatchResult var ty match_alts 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))) + unboxAlt = do + l <- newSysLocalDs intPrimTy + indexP <- dsLookupGlobalId indexPName + alts <- mapM (mkAlt indexP) sorted_alts + return (DataAlt intDataCon, [l], (Case (Var l) wild ty (dft : alts))) where wild = mkWildId intPrimTy dft = (DEFAULT, [], fail) @@ -392,9 +464,9 @@ mkCoAlgCaseMatchResult var ty match_alts -- 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) + mkAlt indexP (con, args, MatchResult _ bodyFun) = do + body <- bodyFun fail + return (LitAlt lit, [], mkDsLets binds body) where lit = MachInt $ toInteger (dataConSourceArity con) binds = [NonRec arg (indexExpr i) | (i, arg) <- zip [1..] args] @@ -415,14 +487,13 @@ mkErrorAppDs :: Id -- The error function -> String -- The error message string to pass -> DsM CoreExpr -mkErrorAppDs err_id ty msg - = getSrcSpanDs `thenDs` \ src_loc -> +mkErrorAppDs err_id ty msg = do + src_loc <- getSrcSpanDs let - full_msg = showSDoc (hcat [ppr src_loc, text "|", text msg]) - core_msg = Lit (mkStringLit full_msg) - -- mkStringLit returns a result of type String# - in - returnDs (mkApps (Var err_id) [Type ty, core_msg]) + full_msg = showSDoc (hcat [ppr src_loc, text "|", text msg]) + core_msg = Lit (mkStringLit full_msg) + -- mkStringLit returns a result of type String# + return (mkApps (Var err_id) [Type ty, core_msg]) \end{code} @@ -443,57 +514,55 @@ mkIntExpr i = mkConApp intDataCon [mkIntLit i] mkCharExpr c = mkConApp charDataCon [mkLit (MachChar c)] mkIntegerExpr i - | inIntRange i -- Small enough, so start from an Int - = dsLookupDataCon smallIntegerDataConName `thenDs` \ integer_dc -> - returnDs (mkSmallIntegerLit integer_dc i) + | inIntRange i -- Small enough, so start from an Int + = do integer_id <- dsLookupGlobalId smallIntegerName + return (mkSmallIntegerLit integer_id 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 -> - 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 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 small_integer_data_con i = mkConApp small_integer_data_con [mkIntLit i] + | otherwise = do -- Big, so start from a string + plus_id <- dsLookupGlobalId plusIntegerName + times_id <- dsLookupGlobalId timesIntegerName + integer_id <- dsLookupGlobalId smallIntegerName + let + lit i = mkSmallIntegerLit integer_id 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 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 + + return (horner tARGET_MAX_INT i) + +mkSmallIntegerLit :: Id -> Integer -> CoreExpr +mkSmallIntegerLit small_integer i = mkApps (Var small_integer) [mkIntLit i] mkStringExpr str = mkStringExprFS (mkFastString str) mkStringExprFS str | nullFS str - = returnDs (mkNilExpr charTy) + = return (mkNilExpr charTy) | lengthFS str == 1 - = let - the_char = mkCharExpr (headFS str) - in - returnDs (mkConsExpr charTy the_char (mkNilExpr charTy)) + = do let the_char = mkCharExpr (headFS str) + return (mkConsExpr charTy the_char (mkNilExpr charTy)) | all safeChar chars - = dsLookupGlobalId unpackCStringName `thenDs` \ unpack_id -> - returnDs (App (Var unpack_id) (Lit (MachStr str))) + = do unpack_id <- dsLookupGlobalId unpackCStringName + return (App (Var unpack_id) (Lit (MachStr str))) | otherwise - = dsLookupGlobalId unpackCStringUtf8Name `thenDs` \ unpack_id -> - returnDs (App (Var unpack_id) (Lit (MachStr str))) + = do unpack_id <- dsLookupGlobalId unpackCStringUtf8Name + return (App (Var unpack_id) (Lit (MachStr str))) where chars = unpackFS str @@ -529,63 +598,60 @@ mkSelectorBinds :: LPat Id -- The pattern -> DsM [(Id,CoreExpr)] mkSelectorBinds (L _ (VarPat v)) val_expr - = returnDs [(v, val_expr)] + = return [(v, val_expr)] mkSelectorBinds pat val_expr - | 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 (hsLPatType 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) : - (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 -> - let - mk_tup_bind binder - = (binder, mkTupleSelector binders binder tuple_var (Var tuple_var)) - in - returnDs ( (tuple_var, tuple_expr) : map mk_tup_bind binders ) + | isSingleton binders || is_simple_lpat pat = do + -- 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. + val_var <- newSysLocalDs (hsLPatType pat) + + -- 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 + err_expr <- mkErrorAppDs iRREFUT_PAT_ERROR_ID unitTy (showSDoc (ppr pat)) + err_var <- newSysLocalDs unitTy + binds <- mapM (mk_bind val_var err_var) binders + return ( (val_var, val_expr) : + (err_var, err_expr) : + binds ) + + + | otherwise = do + error_expr <- mkErrorAppDs iRREFUT_PAT_ERROR_ID tuple_ty (showSDoc (ppr pat)) + tuple_expr <- matchSimply val_expr PatBindRhs pat local_tuple error_expr + tuple_var <- newSysLocalDs tuple_ty + let + mk_tup_bind binder + = (binder, mkTupleSelector binders binder tuple_var (Var tuple_var)) + return ( (tuple_var, tuple_expr) : map mk_tup_bind binders ) where - binders = collectPatBinders pat - local_tuple = mkTupleExpr binders + binders = collectPatBinders pat + local_tuple = mkBigCoreVarTup binders tuple_ty = exprType local_tuple - mk_bind scrut_var err_var bndr_var + mk_bind scrut_var err_var bndr_var = do -- (mk_bind sv err_var) generates - -- bv = case sv of { pat -> bv; other -> coerce (type-of-bv) err_var } + -- 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) + rhs_expr <- matchSimply (Var scrut_var) PatBindRhs pat + (Var bndr_var) error_expr + return (bndr_var, rhs_expr) where error_expr = mkCoerce co (Var err_var) co = mkUnsafeCoercion (exprType (Var err_var)) (idType bndr_var) @@ -593,46 +659,30 @@ mkSelectorBinds pat val_expr is_simple_lpat p = is_simple_pat (unLoc p) is_simple_pat (TuplePat ps Boxed _) = all is_triv_lpat ps - is_simple_pat (ConPatOut{ pat_args = 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 (ConPatOut{ pat_args = ps }) = all is_triv_lpat (hsConPatArgs ps) + is_simple_pat (VarPat _) = True + is_simple_pat (ParPat p) = is_simple_lpat p + is_simple_pat _ = False is_triv_lpat p = is_triv_pat (unLoc p) - is_triv_pat (VarPat v) = True + is_triv_pat (VarPat _) = True is_triv_pat (WildPat _) = True is_triv_pat (ParPat p) = is_triv_lpat p - is_triv_pat other = False + is_triv_pat _ = False \end{code} %************************************************************************ %* * - Tuples + Big 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) - -mkBigCoreTup :: [CoreExpr] -> CoreExpr -mkBigCoreTup = mkBigTuple mkCoreTup mkBigTuple :: ([a] -> a) -> [a] -> a mkBigTuple small_tuple as = mk_big_tuple (chunkify as) @@ -646,11 +696,99 @@ chunkify :: [a] -> [[a]] -- 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) + | 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} + +Creating tuples and their types for Core expressions + +@mkBigCoreVarTup@ 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. + +\begin{code} + +-- Small tuples: build exactly the specified tuple +mkCoreVarTup :: [Id] -> CoreExpr +mkCoreVarTup ids = mkCoreTup (map Var ids) + +mkCoreVarTupTy :: [Id] -> Type +mkCoreVarTupTy ids = mkCoreTupTy (map idType ids) + + +mkCoreTup :: [CoreExpr] -> CoreExpr +mkCoreTup [] = Var unitDataConId +mkCoreTup [c] = c +mkCoreTup cs = mkConApp (tupleCon Boxed (length cs)) + (map (Type . exprType) cs ++ cs) + +mkCoreTupTy :: [Type] -> Type +mkCoreTupTy [ty] = ty +mkCoreTupTy tys = mkTupleTy Boxed (length tys) tys + + + +-- Big tuples +mkBigCoreVarTup :: [Id] -> CoreExpr +mkBigCoreVarTup ids = mkBigCoreTup (map Var ids) + +mkBigCoreVarTupTy :: [Id] -> Type +mkBigCoreVarTupTy ids = mkBigCoreTupTy (map idType ids) + + +mkBigCoreTup :: [CoreExpr] -> CoreExpr +mkBigCoreTup = mkBigTuple mkCoreTup + +mkBigCoreTupTy :: [Type] -> Type +mkBigCoreTupTy = mkBigTuple mkCoreTupTy + +\end{code} + +Creating tuples and their types for full Haskell expressions + +\begin{code} + +-- Smart constructors for source tuple expressions +mkLHsVarTup :: [Id] -> LHsExpr Id +mkLHsVarTup ids = mkLHsTup (map nlHsVar ids) + +mkLHsTup :: [LHsExpr Id] -> LHsExpr Id +mkLHsTup [] = nlHsVar unitDataConId +mkLHsTup [lexp] = lexp +mkLHsTup lexps = noLoc $ ExplicitTuple lexps Boxed + + +-- Smart constructors for source tuple patterns +mkLHsVarPatTup :: [Id] -> LPat Id +mkLHsVarPatTup bs = mkLHsPatTup (map nlVarPat bs) + +mkLHsPatTup :: [LPat Id] -> LPat Id +mkLHsPatTup [lpat] = lpat +mkLHsPatTup lpats = noLoc $ mkVanillaTuplePat lpats Boxed -- Handles the case where lpats = [] gracefully + + +-- The Big equivalents for the source tuple expressions +mkBigLHsVarTup :: [Id] -> LHsExpr Id +mkBigLHsVarTup ids = mkBigLHsTup (map nlHsVar ids) + +mkBigLHsTup :: [LHsExpr Id] -> LHsExpr Id +mkBigLHsTup = mkBigTuple mkLHsTup + + +-- The Big equivalents for the source tuple patterns +mkBigLHsVarPatTup :: [Id] -> LPat Id +mkBigLHsVarPatTup bs = mkBigLHsPatTup (map nlVarPat bs) + +mkBigLHsPatTup :: [LPat Id] -> LPat Id +mkBigLHsPatTup = mkBigTuple mkLHsPatTup + \end{code} @@ -723,20 +861,21 @@ mkTupleCase mkTupleCase uniqs vars body scrut_var scrut = mk_tuple_case uniqs (chunkify vars) body where - mk_tuple_case us [vars] body + -- This is the case where don't need any nesting + mk_tuple_case _ [vars] body = mkSmallTupleCase vars body scrut_var scrut + + -- This is the case where we must make nest tuples at least once 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' + = 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') + = 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. @@ -774,40 +913,48 @@ 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) +mkFoldrExpr :: PostTcType -> PostTcType -> CoreExpr -> CoreExpr -> CoreExpr -> DsM CoreExpr +mkFoldrExpr elt_ty result_ty c n list = do + foldr_id <- dsLookupGlobalId foldrName + return (Var foldr_id `App` Type elt_ty + `App` Type result_ty + `App` c + `App` n + `App` list) + +mkBuildExpr :: Type -> ((Id, Type) -> (Id, Type) -> DsM CoreExpr) -> DsM CoreExpr +mkBuildExpr elt_ty mk_build_inside = do + [n_tyvar] <- newTyVarsDs [alphaTyVar] + let n_ty = mkTyVarTy n_tyvar + c_ty = mkFunTys [elt_ty, n_ty] n_ty + [c, n] <- newSysLocalsDs [c_ty, n_ty] + + build_inside <- mk_build_inside (c, c_ty) (n, n_ty) + + build_id <- dsLookupGlobalId buildName + return $ Var build_id `App` Type elt_ty `App` mkLams [n_tyvar, c, n] build_inside mkCoreSel :: [Id] -- The tuple args - -> Id -- The selected one - -> Id -- A variable of the same type as the scrutinee + -> 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 + +-- mkCoreSel [x] x v e +-- ===> e +mkCoreSel [var] should_be_the_same_var _ scrut = ASSERT(var == should_be_the_same_var) scrut +-- mkCoreSel [x,y,z] x v e +-- ===> case e of v { (x,y,z) -> x 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} - %************************************************************************ %* * \subsection[mkFailurePair]{Code for pattern-matching and other failures} @@ -869,50 +1016,54 @@ mkFailurePair :: CoreExpr -- Result type of the whole case expression CoreExpr) -- Either the fail variable, or fail variable -- applied to unit tuple mkFailurePair expr - | isUnLiftedType ty - = newFailLocalDs (unitTy `mkFunTy` ty) `thenDs` \ fail_fun_var -> - newSysLocalDs unitTy `thenDs` \ fail_fun_arg -> - returnDs (NonRec fail_fun_var (Lam fail_fun_arg expr), - App (Var fail_fun_var) (Var unitDataConId)) - - | otherwise - = newFailLocalDs ty `thenDs` \ fail_var -> - returnDs (NonRec fail_var expr, Var fail_var) + | isUnLiftedType ty = do + fail_fun_var <- newFailLocalDs (unitTy `mkFunTy` ty) + fail_fun_arg <- newSysLocalDs unitTy + return (NonRec fail_fun_var (Lam fail_fun_arg expr), + App (Var fail_fun_var) (Var unitDataConId)) + + | otherwise = do + fail_var <- newFailLocalDs ty + return (NonRec fail_var expr, Var fail_var) where ty = exprType expr \end{code} \begin{code} -mkOptTickBox :: Maybe Int -> CoreExpr -> DsM CoreExpr +mkOptTickBox :: Maybe (Int,[Id]) -> CoreExpr -> DsM CoreExpr mkOptTickBox Nothing e = return e -mkOptTickBox (Just ix) e = mkTickBox ix e +mkOptTickBox (Just (ix,ids)) e = mkTickBox ix ids e -mkTickBox :: Int -> CoreExpr -> DsM CoreExpr -mkTickBox ix e = do +mkTickBox :: Int -> [Id] -> CoreExpr -> DsM CoreExpr +mkTickBox ix vars e = do uq <- newUnique mod <- getModuleDs - let tick = mkTickBoxOpId uq mod ix + let tick | opt_Hpc = mkTickBoxOpId uq mod ix + | otherwise = mkBreakPointOpId uq mod ix uq2 <- newUnique let occName = mkVarOcc "tick" - let name = mkInternalName uq2 occName noSrcLoc -- use mkSysLocal? + let name = mkInternalName uq2 occName noSrcSpan -- use mkSysLocal? let var = Id.mkLocalId name realWorldStatePrimTy - return $ Case (Var tick) - var - ty - [(DEFAULT,[],e)] + scrut <- + if opt_Hpc + then return (Var tick) + else do + let tickVar = Var tick + let tickType = mkFunTys (map idType vars) realWorldStatePrimTy + let scrutApTy = App tickVar (Type tickType) + return (mkApps scrutApTy (map Var vars) :: Expr Id) + return $ Case scrut var ty [(DEFAULT,[],e)] where ty = exprType e mkBinaryTickBox :: Int -> Int -> CoreExpr -> DsM CoreExpr mkBinaryTickBox ixT ixF e = do - mod <- getModuleDs uq <- newUnique - mod <- getModuleDs let bndr1 = mkSysLocal FSLIT("t1") uq boolTy - falseBox <- mkTickBox ixF $ Var falseDataConId - trueBox <- mkTickBox ixT $ Var trueDataConId + falseBox <- mkTickBox ixF [] $ Var falseDataConId + trueBox <- mkTickBox ixT [] $ Var trueDataConId return $ Case e bndr1 boolTy [ (DataAlt falseDataCon, [], falseBox) , (DataAlt trueDataCon, [], trueBox) ] -\end{code} \ No newline at end of file +\end{code}