X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Fspecialise%2FRules.lhs;h=4f538599202d1cfac7f6261b5efd8de3a4d15477;hb=59c796f8e77325d35f29ddd3e724bfa780466d40;hp=1f5e74e607302967308669f1268c763a33ebe3de;hpb=243dedb8741d13162fe944ebf2adace921e0108d;p=ghc-hetmet.git diff --git a/ghc/compiler/specialise/Rules.lhs b/ghc/compiler/specialise/Rules.lhs index 1f5e74e..4f53859 100644 --- a/ghc/compiler/specialise/Rules.lhs +++ b/ghc/compiler/specialise/Rules.lhs @@ -6,9 +6,8 @@ \begin{code} module Rules ( RuleBase, emptyRuleBase, - extendRuleBase, extendRuleBaseList, addRuleBaseFVs, - ruleBaseIds, ruleBaseFVs, - pprRuleBase, + extendRuleBaseList, + ruleBaseIds, pprRuleBase, ruleCheckProgram, lookupRule, addRule, addIdSpecialisations ) where @@ -17,26 +16,28 @@ module Rules ( import CoreSyn -- All of it import OccurAnal ( occurAnalyseRule ) -import CoreFVs ( exprFreeVars, ruleRhsFreeVars, ruleSomeLhsFreeVars ) +import CoreFVs ( exprFreeVars, ruleRhsFreeVars ) import CoreUnfold ( isCheapUnfolding, unfoldingTemplate ) import CoreUtils ( eqExpr ) -import PprCore ( pprCoreRule ) +import CoreTidy ( pprTidyIdRules ) import Subst ( Subst, InScopeSet, mkInScopeSet, lookupSubst, extendSubst, - substEnv, setSubstEnv, emptySubst, isInScope, + substEnv, setSubstEnv, emptySubst, isInScope, emptyInScopeSet, bindSubstList, unBindSubstList, substInScope, uniqAway ) -import Id ( Id, idUnfolding, zapLamIdInfo, - idSpecialisation, setIdSpecialisation - ) -import Var ( isTyVar, isId ) +import Id ( Id, idUnfolding, idSpecialisation, setIdSpecialisation ) +import Var ( isId ) import VarSet import VarEnv -import Type ( mkTyVarTy ) -import qualified Unify ( match ) +import TcType ( mkTyVarTy ) +import qualified TcType ( match ) +import BasicTypes ( Activation, CompilerPhase, isActive ) import Outputable -import Maybes ( maybeToBool ) -import Util ( sortLt ) +import FastString +import Maybe ( isJust, isNothing, fromMaybe ) +import Util ( sortLe ) +import Bag +import List ( isPrefixOf ) \end{code} @@ -82,16 +83,20 @@ where pi' :: Lift Int# is the specialised version of pi. %************************************************************************ \begin{code} -matchRules :: InScopeSet -> [CoreRule] -> [CoreExpr] -> Maybe (RuleName, CoreExpr) +matchRules :: (Activation -> Bool) -> InScopeSet + -> [CoreRule] -> [CoreExpr] -> Maybe (RuleName, CoreExpr) -- See comments on matchRule -matchRules in_scope [] args = Nothing -matchRules in_scope (rule:rules) args - = case matchRule in_scope rule args of +matchRules is_active in_scope [] args = Nothing +matchRules is_active in_scope (rule:rules) args + = case matchRule is_active in_scope rule args of Just result -> Just result - Nothing -> matchRules in_scope rules args + Nothing -> matchRules is_active in_scope rules args +noBlackList :: Activation -> Bool +noBlackList act = False -- Nothing is black listed -matchRule :: InScopeSet -> CoreRule -> [CoreExpr] -> Maybe (RuleName, CoreExpr) +matchRule :: (Activation -> Bool) -> InScopeSet + -> CoreRule -> [CoreExpr] -> Maybe (RuleName, CoreExpr) -- If (matchRule rule args) returns Just (name,rhs) -- then (f args) matches the rule, and the corresponding @@ -136,9 +141,15 @@ matchRule :: InScopeSet -> CoreRule -> [CoreExpr] -> Maybe (RuleName, CoreExpr) -- (\x->E) matches (\x->F x) -matchRule in_scope rule@(BuiltinRule match_fn) args = match_fn args +matchRule is_active in_scope rule@(BuiltinRule name match_fn) args + = case match_fn args of + Just expr -> Just (name,expr) + Nothing -> Nothing -matchRule in_scope rule@(Rule rn tpl_vars tpl_args rhs) args +matchRule is_active in_scope rule@(Rule rn act tpl_vars tpl_args rhs) args + | not (is_active act) + = Nothing + | otherwise = go tpl_args args emptySubst -- We used to use the in_scope set, but I don't think that's necessary -- After all, the result is going to be simplified again with that in_scope set @@ -182,7 +193,7 @@ matchRule in_scope rule@(Rule rn tpl_vars tpl_args rhs) args mk_result_args subst done) Nothing -> Nothing -- Failure where - (done, leftovers) = partition (\v -> maybeToBool (lookupSubstEnv subst_env v)) + (done, leftovers) = partition (\v -> isJust (lookupSubstEnv subst_env v)) (map zapOccInfo tpl_vars) -- Zap the occ info subst_env = substEnv subst @@ -239,10 +250,10 @@ match (Var v1) e2 tpl_vars kont subst kont (extendSubst subst v1 (DoneEx e2)) - | eqExpr (Var v1) e2 -> kont subst + | eqExpr (Var v1) e2 -> kont subst -- v1 is not a template variable, so it must be a global constant - Just (DoneEx e2') | eqExpr e2' e2 -> kont subst + Just (DoneEx e2') | eqExpr e2' e2 -> kont subst other -> match_fail @@ -281,7 +292,7 @@ match e1 (Lam x2 e2) tpl_vars kont subst match (Case e1 x1 alts1) (Case e2 x2 alts2) tpl_vars kont subst = match e1 e2 tpl_vars case_kont subst where - case_kont subst = bind [x1] [x2] (match_alts alts1 (sortLt lt_alt alts2)) + case_kont subst = bind [x1] [x2] (match_alts alts1 (sortLe le_alt alts2)) tpl_vars kont subst match (Type ty1) (Type ty2) tpl_vars kont subst @@ -336,7 +347,7 @@ match_alts ((c1,vs1,r1):alts1) ((c2,vs2,r2):alts2) tpl_vars kont subst subst match_alts alts1 alts2 tpl_vars kont subst = match_fail -lt_alt (con1, _, _) (con2, _, _) = con1 < con2 +le_alt (con1, _, _) (con2, _, _) = con1 <= con2 ---------------------------------------- bind :: [CoreBndr] -- Template binders @@ -357,29 +368,31 @@ bind vs1 vs2 matcher tpl_vars kont subst subst' = bindSubstList subst vs1 vs2 -- The unBindSubst relies on no shadowing in the template - not_in_subst v = not (maybeToBool (lookupSubst subst v)) + not_in_subst v = isNothing (lookupSubst subst v) bug_msg = sep [ppr vs1, ppr vs2] ---------------------------------------- -match_ty ty1 ty2 tpl_vars kont subst - = case Unify.match ty1 ty2 tpl_vars Just (substEnv subst) of - Nothing -> match_fail - Just senv' -> kont (setSubstEnv subst senv') - ----------------------------------------- -matches [] [] tpl_vars kont subst - = kont subst -matches (e:es) (e':es') tpl_vars kont subst - = match e e' tpl_vars (matches es es' tpl_vars kont) subst -matches es es' tpl_vars kont subst - = match_fail - ----------------------------------------- mkVarArg :: CoreBndr -> CoreArg mkVarArg v | isId v = Var v | otherwise = Type (mkTyVarTy v) \end{code} +Matching Core types: use the matcher in TcType. +Notice that we treat newtypes as opaque. For example, suppose +we have a specialised version of a function at a newtype, say + newtype T = MkT Int +We only want to replace (f T) with f', not (f Int). + +\begin{code} +---------------------------------------- +match_ty ty1 ty2 tpl_vars kont subst + = TcType.match ty1 ty2 tpl_vars kont' (substEnv subst) + where + kont' senv = kont (setSubstEnv subst senv) +\end{code} + + + %************************************************************************ %* * \subsection{Adding a new rule} @@ -387,7 +400,11 @@ mkVarArg v | isId v = Var v %************************************************************************ \begin{code} -addRule :: CoreRules -> Id -> CoreRule -> CoreRules +addRule :: Id -> CoreRules -> CoreRule -> CoreRules + +-- Add a new rule to an existing bunch of rules. +-- The rules are for the given Id; the Id argument is needed only +-- so that we can exclude the Id from its own RHS free-var set -- Insert the new rule just before a rule that is *less specific* -- than the new one; or at the end if there isn't such a one. @@ -397,11 +414,11 @@ addRule :: CoreRules -> Id -> CoreRule -> CoreRules -- We make no check for rules that unify without one dominating -- the other. Arguably this would be a bug. -addRule (Rules rules rhs_fvs) id rule@(BuiltinRule _) +addRule id (Rules rules rhs_fvs) rule@(BuiltinRule _ _) = Rules (rule:rules) rhs_fvs -- Put it at the start for lack of anything better -addRule (Rules rules rhs_fvs) id rule +addRule id (Rules rules rhs_fvs) rule = Rules (insertRule rules new_rule) (rhs_fvs `unionVarSet` new_rhs_fvs) where new_rule = occurAnalyseRule rule @@ -412,7 +429,7 @@ addRule (Rules rules rhs_fvs) id rule -- that shoudn't be. E.g. -- RULE: f (f x y) z ==> f x (f y z) -insertRule rules new_rule@(Rule _ tpl_vars tpl_args _) +insertRule rules new_rule@(Rule _ _ tpl_vars tpl_args _) = go rules where tpl_var_set = mkInScopeSet (mkVarSet tpl_vars) @@ -423,29 +440,137 @@ insertRule rules new_rule@(Rule _ tpl_vars tpl_args _) go (rule:rules) | new_is_more_specific rule = (new_rule:rule:rules) | otherwise = rule : go rules - new_is_more_specific rule = maybeToBool (matchRule tpl_var_set rule tpl_args) + new_is_more_specific rule = isJust (matchRule noBlackList tpl_var_set rule tpl_args) -addIdSpecialisations :: Id -> [([CoreBndr], [CoreExpr], CoreExpr)] -> Id -addIdSpecialisations id spec_stuff - = setIdSpecialisation id new_rules +addIdSpecialisations :: Id -> [CoreRule] -> Id +addIdSpecialisations id rules + = setIdSpecialisation id new_specs where - rule_name = _PK_ ("SPEC " ++ showSDoc (ppr id)) - new_rules = foldr add (idSpecialisation id) spec_stuff - add (vars, args, rhs) rules = addRule rules id (Rule rule_name vars args rhs) + new_specs = foldl (addRule id) (idSpecialisation id) rules \end{code} %************************************************************************ %* * -\subsection{Preparing the rule base +\subsection{Looking up a rule} %* * %************************************************************************ \begin{code} -lookupRule :: InScopeSet -> Id -> [CoreExpr] -> Maybe (RuleName, CoreExpr) -lookupRule in_scope fn args +lookupRule :: (Activation -> Bool) -> InScopeSet + -> Id -> [CoreExpr] -> Maybe (RuleName, CoreExpr) +lookupRule is_active in_scope fn args = case idSpecialisation fn of - Rules rules _ -> matchRules in_scope rules args + Rules rules _ -> matchRules is_active in_scope rules args +\end{code} + + +%************************************************************************ +%* * +\subsection{Checking a program for failing rule applications} +%* * +%************************************************************************ + +----------------------------------------------------- + Game plan +----------------------------------------------------- + +We want to know what sites have rules that could have fired but didn't. +This pass runs over the tree (without changing it) and reports such. + +NB: we assume that this follows a run of the simplifier, so every Id +occurrence (including occurrences of imported Ids) is decorated with +all its (active) rules. No need to construct a rule base or anything +like that. + +\begin{code} +ruleCheckProgram :: CompilerPhase -> String -> [CoreBind] -> SDoc +-- Report partial matches for rules beginning +-- with the specified string +ruleCheckProgram phase rule_pat binds + | isEmptyBag results + = text "Rule check results: no rule application sites" + | otherwise + = vcat [text "Rule check results:", + line, + vcat [ p $$ line | p <- bagToList results ] + ] + where + results = unionManyBags (map (ruleCheckBind (phase, rule_pat)) binds) + line = text (replicate 20 '-') + +type RuleCheckEnv = (CompilerPhase, String) -- Phase and Pattern + +ruleCheckBind :: RuleCheckEnv -> CoreBind -> Bag SDoc + -- The Bag returned has one SDoc for each call site found +ruleCheckBind env (NonRec b r) = ruleCheck env r +ruleCheckBind env (Rec prs) = unionManyBags [ruleCheck env r | (b,r) <- prs] + +ruleCheck :: RuleCheckEnv -> CoreExpr -> Bag SDoc +ruleCheck env (Var v) = emptyBag +ruleCheck env (Lit l) = emptyBag +ruleCheck env (Type ty) = emptyBag +ruleCheck env (App f a) = ruleCheckApp env (App f a) [] +ruleCheck env (Note n e) = ruleCheck env e +ruleCheck env (Let bd e) = ruleCheckBind env bd `unionBags` ruleCheck env e +ruleCheck env (Lam b e) = ruleCheck env e +ruleCheck env (Case e _ as) = ruleCheck env e `unionBags` + unionManyBags [ruleCheck env r | (_,_,r) <- as] + +ruleCheckApp env (App f a) as = ruleCheck env a `unionBags` ruleCheckApp env f (a:as) +ruleCheckApp env (Var f) as = ruleCheckFun env f as +ruleCheckApp env other as = ruleCheck env other +\end{code} + +\begin{code} +ruleCheckFun :: RuleCheckEnv -> Id -> [CoreExpr] -> Bag SDoc +-- Produce a report for all rules matching the predicate +-- saying why it doesn't match the specified application + +ruleCheckFun (phase, pat) fn args + | null name_match_rules = emptyBag + | otherwise = unitBag (ruleAppCheck_help phase fn args name_match_rules) + where + name_match_rules = case idSpecialisation fn of + Rules rules _ -> filter match rules + match rule = pat `isPrefixOf` unpackFS (ruleName rule) + +ruleAppCheck_help :: CompilerPhase -> Id -> [CoreExpr] -> [CoreRule] -> SDoc +ruleAppCheck_help phase fn args rules + = -- The rules match the pattern, so we want to print something + vcat [text "Expression:" <+> ppr (mkApps (Var fn) args), + vcat (map check_rule rules)] + where + n_args = length args + i_args = args `zip` [1::Int ..] + + check_rule rule = rule_herald rule <> colon <+> rule_info rule + + rule_herald (BuiltinRule name _) = + ptext SLIT("Builtin rule") <+> doubleQuotes (ftext name) + rule_herald (Rule name _ _ _ _) = + ptext SLIT("Rule") <+> doubleQuotes (ftext name) + + rule_info rule + | Just (name,_) <- matchRule noBlackList emptyInScopeSet rule args + = text "matches (which is very peculiar!)" + + rule_info (BuiltinRule name fn) = text "does not match" + + rule_info (Rule name act rule_bndrs rule_args _) + | not (isActive phase act) = text "active only in later phase" + | n_args < n_rule_args = text "too few arguments" + | n_mismatches == n_rule_args = text "no arguments match" + | n_mismatches == 0 = text "all arguments match (considered individually), but the rule as a whole does not" + | otherwise = text "arguments" <+> ppr mismatches <+> text "do not match (1-indexing)" + where + n_rule_args = length rule_args + n_mismatches = length mismatches + mismatches = [i | (rule_arg, (arg,i)) <- rule_args `zip` i_args, + not (isJust (match_fn rule_arg arg))] + + bndr_set = mkVarSet rule_bndrs + match_fn rule_arg arg = match rule_arg arg bndr_set (\s -> Just ()) emptySubst \end{code} @@ -460,42 +585,27 @@ data RuleBase = RuleBase IdSet -- Ids with their rules in their specialisations -- Held as a set, so that it can simply be the initial -- in-scope set in the simplifier - - IdSet -- Ids (whether local or imported) mentioned on - -- LHS of some rule; these should be black listed - -- This representation is a bit cute, and I wonder if we should -- change it to use (IdEnv CoreRule) which seems a bit more natural -ruleBaseIds (RuleBase ids _) = ids -ruleBaseFVs (RuleBase _ fvs) = fvs - -emptyRuleBase = RuleBase emptyVarSet emptyVarSet - -addRuleBaseFVs :: RuleBase -> IdSet -> RuleBase -addRuleBaseFVs (RuleBase rules fvs) extra_fvs - = RuleBase rules (fvs `unionVarSet` extra_fvs) +ruleBaseIds (RuleBase ids) = ids +emptyRuleBase = RuleBase emptyVarSet extendRuleBaseList :: RuleBase -> [(Id,CoreRule)] -> RuleBase extendRuleBaseList rule_base new_guys = foldl extendRuleBase rule_base new_guys extendRuleBase :: RuleBase -> (Id,CoreRule) -> RuleBase -extendRuleBase (RuleBase rule_ids rule_fvs) (id, rule) +extendRuleBase (RuleBase rule_ids) (id, rule) = RuleBase (extendVarSet rule_ids new_id) - (rule_fvs `unionVarSet` extendVarSet lhs_fvs id) where - new_id = setIdSpecialisation id (addRule old_rules id rule) - old_rules = case lookupVarSet rule_ids id of - Nothing -> emptyCoreRules - Just id' -> idSpecialisation id' - - lhs_fvs = ruleSomeLhsFreeVars isId rule - -- Find *all* the free Ids of the LHS, not just - -- locally defined ones!! + new_id = setIdSpecialisation id (addRule id old_rules rule) + old_rules = idSpecialisation (fromMaybe id (lookupVarSet rule_ids id)) + -- Get the old rules from rule_ids if the Id is already there, but + -- if not, use the Id from the incoming rule. If may be a PrimOpId, + -- in which case it may have rules in its belly already. Seems + -- dreadfully hackoid. pprRuleBase :: RuleBase -> SDoc -pprRuleBase (RuleBase rules _) = vcat [ pprCoreRule (ppr id) rs - | id <- varSetElems rules, - rs <- rulesRules $ idSpecialisation id ] +pprRuleBase (RuleBase rules) = vcat [ pprTidyIdRules id | id <- varSetElems rules ] \end{code}