X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FsimplCore%2FSetLevels.lhs;h=21dca615c3a1d230bfde2c8ff1b0c9e2534f94d6;hp=ebfc27ea6ebad0ad5d5b47ab3f00adaa810f7778;hb=c8c2f6bb7d79a2a6aeaa3233363fdf0bbbfad205;hpb=a66541af84d102f32b73fb7f89f48008c01092a6 diff --git a/compiler/simplCore/SetLevels.lhs b/compiler/simplCore/SetLevels.lhs index ebfc27e..21dca61 100644 --- a/compiler/simplCore/SetLevels.lhs +++ b/compiler/simplCore/SetLevels.lhs @@ -71,7 +71,7 @@ import OccName ( occNameString ) import Type ( isUnLiftedType, Type ) import BasicTypes ( TopLevelFlag(..), Arity ) import UniqSupply -import Util ( sortLe, isSingleton, count ) +import Util import Outputable import FastString \end{code} @@ -243,6 +243,7 @@ If there were another lambda in @r@'s rhs, it would get level-2 as well. \begin{code} lvlExpr _ _ ( _, AnnType ty) = return (Type ty) +lvlExpr _ _ ( _, AnnCoercion co) = return (Coercion co) lvlExpr _ env (_, AnnVar v) = return (lookupVar env v) lvlExpr _ _ (_, AnnLit lit) = return (Lit lit) @@ -287,7 +288,7 @@ lvlExpr ctxt_lvl env (_, AnnNote note expr) = do expr' <- lvlExpr ctxt_lvl env expr return (Note note expr') -lvlExpr ctxt_lvl env (_, AnnCast expr co) = do +lvlExpr ctxt_lvl env (_, AnnCast expr (_, co)) = do expr' <- lvlExpr ctxt_lvl env expr return (Cast expr' co) @@ -414,7 +415,7 @@ lvlMFE strict_ctxt ctxt_lvl env (_, AnnNote n e) = do { e' <- lvlMFE strict_ctxt ctxt_lvl env e ; return (Note n e') } -lvlMFE strict_ctxt ctxt_lvl env (_, AnnCast e co) +lvlMFE strict_ctxt ctxt_lvl env (_, AnnCast e (_, co)) = do { e' <- lvlMFE strict_ctxt ctxt_lvl env e ; return (Cast e' co) } @@ -423,7 +424,9 @@ lvlMFE True ctxt_lvl env e@(_, AnnCase {}) = lvlExpr ctxt_lvl env e -- Don't share cases lvlMFE strict_ctxt ctxt_lvl env ann_expr@(fvs, _) - | isUnLiftedType ty -- Can't let-bind it; see Note [Unlifted MFEs] + | isUnLiftedType ty -- Can't let-bind it; see Note [Unlifted MFEs] + -- This includes coercions, which we don't + -- want to float anyway || notWorthFloating ann_expr abs_vars || not good_destination = -- Don't float it out @@ -491,6 +494,7 @@ notWorthFloating e abs_vars go (_, AnnCast e _) n = go e n go (_, AnnApp e arg) n | (_, AnnType {}) <- arg = go e n + | (_, AnnCoercion {}) <- arg = go e n | n==0 = False | is_triv arg = go e (n-1) | otherwise = False @@ -500,6 +504,7 @@ notWorthFloating e abs_vars is_triv (_, AnnVar {}) = True -- (ie not worth floating) is_triv (_, AnnCast e _) = is_triv e is_triv (_, AnnApp e (_, AnnType {})) = is_triv e + is_triv (_, AnnApp e (_, AnnCoercion {})) = is_triv e is_triv _ = False \end{code} @@ -563,7 +568,7 @@ lvlBind :: TopLevelFlag -- Used solely to decide whether to clone -> LvlM (LevelledBind, LevelEnv) lvlBind top_lvl ctxt_lvl env (AnnNonRec bndr rhs@(rhs_fvs,_)) - | isTyCoVar bndr -- Don't do anything for TyVar binders + | isTyVar bndr -- Don't do anything for TyVar binders -- (simplifier gets rid of them pronto) = do rhs' <- lvlExpr ctxt_lvl env rhs return (NonRec (TB bndr ctxt_lvl) rhs', env) @@ -591,11 +596,13 @@ lvlBind top_lvl ctxt_lvl env (AnnNonRec bndr rhs@(rhs_fvs,_)) \begin{code} lvlBind top_lvl ctxt_lvl env (AnnRec pairs) - | null abs_vars + | null abs_vars = do (new_env, new_bndrs) <- cloneRecVars top_lvl env bndrs ctxt_lvl dest_lvl new_rhss <- mapM (lvlExpr ctxt_lvl new_env) rhss return (Rec ([TB b dest_lvl | b <- new_bndrs] `zip` new_rhss), new_env) +-- ToDo: when enabling the floatLambda stuff, +-- I think we want to stop doing this | isSingleton pairs && count isId abs_vars > 1 = do -- Special case for self recursion where there are -- several variables carried around: build a local loop: @@ -671,26 +678,15 @@ lvlLamBndrs lvl [] = (lvl, []) lvlLamBndrs lvl bndrs - = go (incMinorLvl lvl) - False -- Havn't bumped major level in this group - [] bndrs + = (new_lvl, [TB bndr new_lvl | bndr <- bndrs]) + -- All the new binders get the same level, because + -- any floating binding is either going to float past + -- all or none. We never separate binders where - go old_lvl bumped_major rev_lvld_bndrs (bndr:bndrs) - | isId bndr && -- Go to the next major level if this is a value binder, - not bumped_major && -- and we havn't already gone to the next level (one jump per group) - not (isOneShotLambda bndr) -- and it isn't a one-shot lambda - = go new_lvl True (TB bndr new_lvl : rev_lvld_bndrs) bndrs - - | otherwise - = go old_lvl bumped_major (TB bndr old_lvl : rev_lvld_bndrs) bndrs + new_lvl | any is_major bndrs = incMajorLvl lvl + | otherwise = incMinorLvl lvl - where - new_lvl = incMajorLvl old_lvl - - go old_lvl _ rev_lvld_bndrs [] - = (old_lvl, reverse rev_lvld_bndrs) - -- a lambda like this (\x -> coerce t (\s -> ...)) - -- This happens quite a bit in state-transformer programs + is_major bndr = isId bndr && not (isOneShotLambda bndr) \end{code} \begin{code} @@ -700,8 +696,11 @@ destLevel :: LevelEnv -> VarSet -> Bool -> Maybe (Arity, StrictSig) -> Level destLevel env fvs is_function mb_bot | Just {} <- mb_bot = tOP_LEVEL -- Send bottoming bindings to the top -- regardless; see Note [Bottoming floats] - | floatLams env - && is_function = tOP_LEVEL -- Send functions to top level; see + | Just n_args <- floatLams env + , n_args > 0 -- n=0 case handled uniformly by the 'otherwise' case + , is_function + , countFreeIds fvs <= n_args + = tOP_LEVEL -- Send functions to top level; see -- the comments with isFunction | otherwise = maxIdLevel env fvs @@ -724,6 +723,13 @@ isFunction (_, AnnLam b e) | isId b = True | otherwise = isFunction e isFunction (_, AnnNote _ e) = isFunction e isFunction _ = False + +countFreeIds :: VarSet -> Int +countFreeIds = foldVarSet add 0 + where + add :: Var -> Int -> Int + add v n | isId v = n+1 + | otherwise = n \end{code} @@ -734,51 +740,55 @@ isFunction _ = False %************************************************************************ \begin{code} -type LevelEnv = (FloatOutSwitches, - VarEnv Level, -- Domain is *post-cloned* TyVars and Ids - Subst, -- Domain is pre-cloned Ids; tracks the in-scope set - -- so that subtitution is capture-avoiding - IdEnv ([Var], LevelledExpr)) -- Domain is pre-cloned Ids +data LevelEnv + = LE { le_switches :: FloatOutSwitches + , le_lvl_env :: VarEnv Level -- Domain is *post-cloned* TyVars and Ids + , le_subst :: Subst -- Domain is pre-cloned Ids; tracks the in-scope set + -- so that subtitution is capture-avoiding + , le_env :: IdEnv ([Var], LevelledExpr) -- Domain is pre-cloned Ids + } -- We clone let-bound variables so that they are still - -- distinct when floated out; hence the SubstEnv/IdEnv. + -- distinct when floated out; hence the le_subst/le_env. -- (see point 3 of the module overview comment). -- We also use these envs when making a variable polymorphic -- because we want to float it out past a big lambda. -- - -- The Subst and IdEnv always implement the same mapping, but the - -- Subst maps to CoreExpr and the IdEnv to LevelledExpr + -- The le_subst and le_env always implement the same mapping, but the + -- le_subst maps to CoreExpr and the le_env to LevelledExpr -- Since the range is always a variable or type application, -- there is never any difference between the two, but sadly - -- the types differ. The SubstEnv is used when substituting in - -- a variable's IdInfo; the IdEnv when we find a Var. + -- the types differ. The le_subst is used when substituting in + -- a variable's IdInfo; the le_env when we find a Var. -- - -- In addition the IdEnv records a list of tyvars free in the + -- In addition the le_env records a list of tyvars free in the -- type application, just so we don't have to call freeVars on -- the type application repeatedly. -- -- The domain of the both envs is *pre-cloned* Ids, though -- - -- The domain of the VarEnv Level is the *post-cloned* Ids + -- The domain of the le_lvl_env is the *post-cloned* Ids initialEnv :: FloatOutSwitches -> LevelEnv -initialEnv float_lams = (float_lams, emptyVarEnv, emptySubst, emptyVarEnv) +initialEnv float_lams + = LE { le_switches = float_lams, le_lvl_env = emptyVarEnv + , le_subst = emptySubst, le_env = emptyVarEnv } -floatLams :: LevelEnv -> Bool -floatLams (fos, _, _, _) = floatOutLambdas fos +floatLams :: LevelEnv -> Maybe Int +floatLams le = floatOutLambdas (le_switches le) floatConsts :: LevelEnv -> Bool -floatConsts (fos, _, _, _) = floatOutConstants fos +floatConsts le = floatOutConstants (le_switches le) floatPAPs :: LevelEnv -> Bool -floatPAPs (fos, _, _, _) = floatOutPartialApplications fos +floatPAPs le = floatOutPartialApplications (le_switches le) extendLvlEnv :: LevelEnv -> [TaggedBndr Level] -> LevelEnv -- Used when *not* cloning -extendLvlEnv (float_lams, lvl_env, subst, id_env) prs - = (float_lams, - foldl add_lvl lvl_env prs, - foldl del_subst subst prs, - foldl del_id id_env prs) +extendLvlEnv le@(LE { le_lvl_env = lvl_env, le_subst = subst, le_env = id_env }) + prs + = le { le_lvl_env = foldl add_lvl lvl_env prs + , le_subst = foldl del_subst subst prs + , le_env = foldl del_id id_env prs } where add_lvl env (TB v l) = extendVarEnv env v l del_subst env (TB v _) = extendInScope env v @@ -798,48 +808,50 @@ extendLvlEnv (float_lams, lvl_env, subst, id_env) prs -- KSW 2000-07. extendInScopeEnv :: LevelEnv -> Var -> LevelEnv -extendInScopeEnv (fl, le, subst, ids) v = (fl, le, extendInScope subst v, ids) +extendInScopeEnv le@(LE { le_subst = subst }) v + = le { le_subst = extendInScope subst v } extendInScopeEnvList :: LevelEnv -> [Var] -> LevelEnv -extendInScopeEnvList (fl, le, subst, ids) vs = (fl, le, extendInScopeList subst vs, ids) +extendInScopeEnvList le@(LE { le_subst = subst }) vs + = le { le_subst = extendInScopeList subst vs } -- extendCaseBndrLvlEnv adds the mapping case-bndr->scrut-var if it can -- (see point 4 of the module overview comment) extendCaseBndrLvlEnv :: LevelEnv -> Expr (TaggedBndr Level) -> Var -> Level -> LevelEnv -extendCaseBndrLvlEnv (float_lams, lvl_env, subst, id_env) (Var scrut_var) case_bndr lvl - = (float_lams, - extendVarEnv lvl_env case_bndr lvl, - extendIdSubst subst case_bndr (Var scrut_var), - extendVarEnv id_env case_bndr ([scrut_var], Var scrut_var)) +extendCaseBndrLvlEnv le@(LE { le_lvl_env = lvl_env, le_subst = subst, le_env = id_env }) + (Var scrut_var) case_bndr lvl + = le { le_lvl_env = extendVarEnv lvl_env case_bndr lvl + , le_subst = extendIdSubst subst case_bndr (Var scrut_var) + , le_env = extendVarEnv id_env case_bndr ([scrut_var], Var scrut_var) } extendCaseBndrLvlEnv env _scrut case_bndr lvl - = extendLvlEnv env [TB case_bndr lvl] + = extendLvlEnv env [TB case_bndr lvl] extendPolyLvlEnv :: Level -> LevelEnv -> [Var] -> [(Var, Var)] -> LevelEnv -extendPolyLvlEnv dest_lvl (float_lams, lvl_env, subst, id_env) abs_vars bndr_pairs - = (float_lams, - foldl add_lvl lvl_env bndr_pairs, - foldl add_subst subst bndr_pairs, - foldl add_id id_env bndr_pairs) +extendPolyLvlEnv dest_lvl + le@(LE { le_lvl_env = lvl_env, le_subst = subst, le_env = id_env }) + abs_vars bndr_pairs + = le { le_lvl_env = foldl add_lvl lvl_env bndr_pairs + , le_subst = foldl add_subst subst bndr_pairs + , le_env = foldl add_id id_env bndr_pairs } where add_lvl env (_, v') = extendVarEnv env v' dest_lvl add_subst env (v, v') = extendIdSubst env v (mkVarApps (Var v') abs_vars) add_id env (v, v') = extendVarEnv env v ((v':abs_vars), mkVarApps (Var v') abs_vars) extendCloneLvlEnv :: Level -> LevelEnv -> Subst -> [(Var, Var)] -> LevelEnv -extendCloneLvlEnv lvl (float_lams, lvl_env, _, id_env) new_subst bndr_pairs - = (float_lams, - foldl add_lvl lvl_env bndr_pairs, - new_subst, - foldl add_id id_env bndr_pairs) +extendCloneLvlEnv lvl le@(LE { le_lvl_env = lvl_env, le_env = id_env }) + new_subst bndr_pairs + = le { le_lvl_env = foldl add_lvl lvl_env bndr_pairs + , le_subst = new_subst + , le_env = foldl add_id id_env bndr_pairs } where add_lvl env (_, v') = extendVarEnv env v' lvl add_id env (v, v') = extendVarEnv env v ([v'], Var v') - maxIdLevel :: LevelEnv -> VarSet -> Level -maxIdLevel (_, lvl_env,_,id_env) var_set +maxIdLevel (LE { le_lvl_env = lvl_env, le_env = id_env }) var_set = foldVarSet max_in tOP_LEVEL var_set where max_in in_var lvl = foldr max_out lvl (case lookupVarEnv id_env in_var of @@ -853,15 +865,15 @@ maxIdLevel (_, lvl_env,_,id_env) var_set | otherwise = lvl -- Ignore tyvars in *maxIdLevel* lookupVar :: LevelEnv -> Id -> LevelledExpr -lookupVar (_, _, _, id_env) v = case lookupVarEnv id_env v of - Just (_, expr) -> expr - _ -> Var v +lookupVar le v = case lookupVarEnv (le_env le) v of + Just (_, expr) -> expr + _ -> Var v abstractVars :: Level -> LevelEnv -> VarSet -> [Var] -- Find the variables in fvs, free vars of the target expresion, -- whose level is greater than the destination level -- These are the ones we are going to abstract out -abstractVars dest_lvl (_, lvl_env, _, id_env) fvs +abstractVars dest_lvl (LE { le_lvl_env = lvl_env, le_env = id_env }) fvs = map zap $ uniq $ sortLe le [var | fv <- varSetElems fvs , var <- absVarsOf id_env fv @@ -876,7 +888,7 @@ abstractVars dest_lvl (_, lvl_env, _, id_env) fvs (False, True) -> False _ -> v1 <= v2 -- Same family - is_tv v = isTyCoVar v && not (isCoVar v) + is_tv v = isTyVar v uniq :: [Var] -> [Var] -- Remove adjacent duplicates; the sort will have brought them together @@ -907,9 +919,7 @@ absVarsOf :: IdEnv ([Var], LevelledExpr) -> Var -> [Var] absVarsOf id_env v | isId v = [av2 | av1 <- lookup_avs v , av2 <- add_tyvars av1] - | isCoVar v = add_tyvars v - | otherwise = [v] - + | otherwise = ASSERT( isTyVar v ) [v] where lookup_avs v = case lookupVarEnv id_env v of Just (abs_vars, _) -> abs_vars @@ -962,11 +972,11 @@ cloneVar TopLevel env v _ _ = return (extendInScopeEnv env v, v) -- Don't clone top level things -- But do extend the in-scope env, to satisfy the in-scope invariant -cloneVar NotTopLevel env@(_,_,subst,_) v ctxt_lvl dest_lvl +cloneVar NotTopLevel env v ctxt_lvl dest_lvl = ASSERT( isId v ) do us <- getUniqueSupplyM let - (subst', v1) = cloneIdBndr subst us v + (subst', v1) = cloneIdBndr (le_subst env) us v v2 = zap_demand ctxt_lvl dest_lvl v1 env' = extendCloneLvlEnv dest_lvl env subst' [(v,v2)] return (env', v2) @@ -974,11 +984,11 @@ cloneVar NotTopLevel env@(_,_,subst,_) v ctxt_lvl dest_lvl cloneRecVars :: TopLevelFlag -> LevelEnv -> [Id] -> Level -> Level -> LvlM (LevelEnv, [Id]) cloneRecVars TopLevel env vs _ _ = return (extendInScopeEnvList env vs, vs) -- Don't clone top level things -cloneRecVars NotTopLevel env@(_,_,subst,_) vs ctxt_lvl dest_lvl +cloneRecVars NotTopLevel env vs ctxt_lvl dest_lvl = ASSERT( all isId vs ) do us <- getUniqueSupplyM let - (subst', vs1) = cloneRecIdBndrs subst us vs + (subst', vs1) = cloneRecIdBndrs (le_subst env) us vs vs2 = map (zap_demand ctxt_lvl dest_lvl) vs1 env' = extendCloneLvlEnv dest_lvl env subst' (vs `zip` vs2) return (env', vs2)