X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Fmain%2FTidyPgm.lhs;h=6a9f0ddfceff4d28cc73b33394d00f1d25624d39;hp=d198a3fe51db055db799b0b989de10938ffbfeaf;hb=c86161c5cf11de77e911fcb9e1e2bd1f8bd80b42;hpb=38b739b7fce555768cf8f0208a081f62eea479cc diff --git a/compiler/main/TidyPgm.lhs b/compiler/main/TidyPgm.lhs index d198a3f..6a9f0dd 100644 --- a/compiler/main/TidyPgm.lhs +++ b/compiler/main/TidyPgm.lhs @@ -16,10 +16,9 @@ import CoreSyn import CoreUnfold import CoreFVs import CoreTidy -import PprCore -import CoreLint +import CoreMonad import CoreUtils -import CoreArity ( exprArity ) +import CoreArity ( exprArity, exprBotStrictness_maybe ) import Class ( classSelIds ) import VarEnv import VarSet @@ -27,9 +26,9 @@ import Var import Id import IdInfo import InstEnv -import NewDemand +import Demand import BasicTypes -import Name +import Name hiding (varName) import NameSet import IfaceEnv import NameEnv @@ -50,8 +49,9 @@ import Data.IORef ( IORef, readIORef, writeIORef ) \end{code} -Constructing the TypeEnv, Instances, Rules from which the ModIface is -constructed, and which goes on to subsequent modules in --make mode. +Constructing the TypeEnv, Instances, Rules, VectInfo from which the +ModIface is constructed, and which goes on to subsequent modules in +--make mode. Most of the interface file is obtained simply by serialising the TypeEnv. One important consequence is that if the *interface file* @@ -296,26 +296,21 @@ tidyProgram hsc_env (ModGuts { mg_module = mod, mg_exports = exports, mg_hpc_info = hpc_info, mg_modBreaks = modBreaks }) - = do { let dflags = hsc_dflags hsc_env - ; showPass dflags "Tidy Core" - - ; let { omit_prags = dopt Opt_OmitInterfacePragmas dflags + = do { let { dflags = hsc_dflags hsc_env + ; omit_prags = dopt Opt_OmitInterfacePragmas dflags + ; expose_all = dopt Opt_ExposeAllUnfoldings dflags ; th = dopt Opt_TemplateHaskell dflags } + ; showPass dflags "Tidy Core" + + ; let { implicit_binds = getImplicitBinds type_env } ; (unfold_env, tidy_occ_env) - <- chooseExternalIds hsc_env mod omit_prags binds - - ; let { ext_rules - | omit_prags = [] - | otherwise = findExternalRules binds imp_rules unfold_env - -- findExternalRules filters imp_rules to avoid binders that - -- aren't externally visible; but the externally-visible binders - -- are computed (by findExternalIds) assuming that all orphan - -- rules are exported (they get their Exported flag set in the desugarer) - -- So in fact we may export more than we need. - -- (It's a sort of mutual recursion.) - } + <- chooseExternalIds hsc_env mod omit_prags expose_all + binds implicit_binds imp_rules + + ; let { ext_rules = findExternalRules omit_prags binds imp_rules unfold_env } + -- See Note [Which rules to expose] ; let { (tidy_env, tidy_binds) = tidyTopBinds hsc_env unfold_env tidy_occ_env binds } @@ -337,18 +332,15 @@ tidyProgram hsc_env (ModGuts { mg_module = mod, mg_exports = exports, -- and indeed it does, but if omit_prags is on, ext_rules is -- empty + ; tidy_vect_info = tidyVectInfo tidy_env vect_info + -- See Note [Injecting implicit bindings] - ; implicit_binds = getImplicitBinds type_env ; all_tidy_binds = implicit_binds ++ tidy_binds ; alg_tycons = filter isAlgTyCon (typeEnvTyCons type_env) } - ; endPass dflags "Tidy Core" Opt_D_dump_simpl all_tidy_binds - ; dumpIfSet_core dflags Opt_D_dump_simpl - "Tidy Core Rules" - (pprRules tidy_rules) - + ; endPass dflags "Tidy Core" Opt_D_dump_simpl all_tidy_binds tidy_rules ; let dir_imp_mods = moduleEnvKeys dir_imps ; return (CgGuts { cg_module = mod, @@ -363,10 +355,10 @@ tidyProgram hsc_env (ModGuts { mg_module = mod, mg_exports = exports, ModDetails { md_types = tidy_type_env, md_rules = tidy_rules, md_insts = tidy_insts, - md_fam_insts = fam_insts, + md_vect_info = tidy_vect_info, + md_fam_insts = fam_insts, md_exports = exports, - md_anns = anns, -- are already tidy - md_vect_info = vect_info -- + md_anns = anns -- are already tidy }) } @@ -475,6 +467,29 @@ tidyInstances tidy_dfun ispecs tidy_dfun (instanceDFunId ispec) \end{code} +\begin{code} +tidyVectInfo :: TidyEnv -> VectInfo -> VectInfo +tidyVectInfo (_, var_env) info@(VectInfo { vectInfoVar = vars + , vectInfoPADFun = pas + , vectInfoIso = isos }) + = info { vectInfoVar = tidy_vars + , vectInfoPADFun = tidy_pas + , vectInfoIso = tidy_isos } + where + tidy_vars = mkVarEnv + $ map tidy_var_mapping + $ varEnvElts vars + + tidy_pas = mapNameEnv tidy_snd_var pas + tidy_isos = mapNameEnv tidy_snd_var isos + + tidy_var_mapping (from, to) = (from', (from', lookup_var to)) + where from' = lookup_var from + tidy_snd_var (x, var) = (x, lookup_var var) + + lookup_var var = lookupWithDefaultVarEnv var_env var var +\end{code} + %************************************************************************ %* * @@ -495,6 +510,11 @@ why CoreUnfold.mkImplicitUnfolding uses simleExprOpt to do a bit of optimisation first. (Only matters when the selector is used curried; eg map x ys.) See Trac #2070. +[Oct 09: in fact, record selectors are no longer implicit Ids at all, +because we really do want to optimise them properly. They are treated +much like any other Id. But doing "light" optimisation on an implicit +Id still makes sense.] + At one time I tried injecting the implicit bindings *early*, at the beginning of SimplCore. But that gave rise to real difficulty, becuase GlobalIds are supposed to have *fixed* IdInfo, but the @@ -505,18 +525,23 @@ importing modules were expecting it to have arity 1 (Trac #2844). It's much safer just to inject them right at the end, after tidying. Oh: two other reasons for injecting them late: + - If implicit Ids are already in the bindings when we start TidyPgm, we'd have to be careful not to treat them as external Ids (in the sense of findExternalIds); else the Ids mentioned in *their* RHSs will be treated as external and you get an interface file saying a18 = but nothing refererring to a18 (because the implicit Id is the - one that does). + one that does, and implicit Ids don't appear in interface files). - More seriously, the tidied type-envt will include the implicit Id replete with a18 in its unfolding; but we won't take account of a18 when computing a fingerprint for the class; result chaos. +There is one sort of implicit binding that is injected still later, +namely those for data constructor workers. Reason (I think): it's +really just a code generation trick.... binding itself makes no sense. +See CorePrep Note [Data constructor workers]. \begin{code} getImplicitBinds :: TypeEnv -> [CoreBind] @@ -528,7 +553,7 @@ getImplicitBinds type_env implicit_ids _ = [] get_defn :: Id -> CoreBind - get_defn id = NonRec id (unfoldingTemplate (idUnfolding id)) + get_defn id = NonRec id (unfoldingTemplate (realIdUnfolding id)) \end{code} @@ -542,45 +567,51 @@ Sete Note [choosing external names]. \begin{code} type UnfoldEnv = IdEnv (Name{-new name-}, Bool {-show unfolding-}) - -- maps each top-level Id to its new Name (the Id is tidied in step 2) - -- The Unique is unchanged. If the new Id is external, it will be + -- Maps each top-level Id to its new Name (the Id is tidied in step 2) + -- The Unique is unchanged. If the new Name is external, it will be -- visible in the interface file. -- -- Bool => expose unfolding or not. chooseExternalIds :: HscEnv -> Module - -> Bool + -> Bool -> Bool -> [CoreBind] + -> [CoreBind] + -> [CoreRule] -> IO (UnfoldEnv, TidyOccEnv) -- Step 1 from the notes above -chooseExternalIds hsc_env mod omit_prags binds - = do - (unfold_env1,occ_env1) - <- search (zip sorted_exports sorted_exports) emptyVarEnv init_occ_env - let internal_ids = filter (not . (`elemVarEnv` unfold_env1)) binders - tidy_internal internal_ids unfold_env1 occ_env1 +chooseExternalIds hsc_env mod omit_prags expose_all binds implicit_binds imp_id_rules + = do { (unfold_env1,occ_env1) <- search init_work_list emptyVarEnv init_occ_env + ; let internal_ids = filter (not . (`elemVarEnv` unfold_env1)) binders + ; tidy_internal internal_ids unfold_env1 occ_env1 } where nc_var = hsc_NC hsc_env - -- the exports, sorted by OccName. This is a deterministic list of - -- Ids (i.e. it's the same list every time this module is compiled), - -- in contrast to the bindings, which are ordered - -- non-deterministically. - -- - -- This list will serve as a starting point for finding a + -- init_ext_ids is the intial list of Ids that should be + -- externalised. It serves as the starting point for finding a -- deterministic, tidy, renaming for all external Ids in this -- module. - sorted_exports = sortBy (compare `on` getOccName) $ - filter isExportedId binders - - binders = bindersOfBinds binds - - bind_env :: IdEnv CoreExpr - bind_env = mkVarEnv (flattenBinds binds) - - avoids = [getOccName name | bndr <- binders, + -- + -- It is sorted, so that it has adeterministic order (i.e. it's the + -- same list every time this module is compiled), in contrast to the + -- bindings, which are ordered non-deterministically. + init_work_list = zip init_ext_ids init_ext_ids + init_ext_ids = sortBy (compare `on` getOccName) $ + filter is_external binders + + -- An Id should be external if either (a) it is exported or + -- (b) it appears in the RHS of a local rule for an imported Id. + -- See Note [Which rules to expose] + is_external id = isExportedId id || id `elemVarSet` rule_rhs_vars + rule_rhs_vars = foldr (unionVarSet . ruleRhsFreeVars) emptyVarSet imp_id_rules + + binders = bindersOfBinds binds + implicit_binders = bindersOfBinds implicit_binds + binder_set = mkVarSet binders + + avoids = [getOccName name | bndr <- binders ++ implicit_binders, let name = idName bndr, isExternalName name ] -- In computing our "avoids" list, we must include @@ -589,6 +620,8 @@ chooseExternalIds hsc_env mod omit_prags binds -- all by the renamer) -- since their names are "taken". -- The type environment is a convenient source of such things. + -- In particular, the set of binders doesn't include + -- implicit Ids at this stage. -- We also make sure to avoid any exported binders. Consider -- f{-u1-} = 1 -- Local decl @@ -601,25 +634,36 @@ chooseExternalIds hsc_env mod omit_prags binds init_occ_env = initTidyOccEnv avoids - search :: [(Id,Id)] -- (external id, referrring id) + search :: [(Id,Id)] -- The work-list: (external id, referrring id) + -- Make a tidy, external Name for the external id, + -- add it to the UnfoldEnv, and do the same for the + -- transitive closure of Ids it refers to + -- The referring id is used to generate a tidy + --- name for the external id -> UnfoldEnv -- id -> (new Name, show_unfold) -> TidyOccEnv -- occ env for choosing new Names -> IO (UnfoldEnv, TidyOccEnv) search [] unfold_env occ_env = return (unfold_env, occ_env) - search ((id,referrer) : rest) unfold_env occ_env - | id `elemVarEnv` unfold_env = search rest unfold_env occ_env + search ((idocc,referrer) : rest) unfold_env occ_env + | idocc `elemVarEnv` unfold_env = search rest unfold_env occ_env | otherwise = do - (occ_env', name') <- tidyTopName mod nc_var (Just referrer) occ_env id + (occ_env', name') <- tidyTopName mod nc_var (Just referrer) occ_env idocc let - rhs = expectJust (showSDoc (text "chooseExternalIds: " <> ppr id)) $ lookupVarEnv bind_env id (new_ids, show_unfold) | omit_prags = ([], False) - | otherwise = addExternal id rhs - unfold_env' = extendVarEnv unfold_env id (name',show_unfold) - referrer' | isExportedId id = id - | otherwise = referrer + | otherwise = addExternal expose_all refined_id + + -- 'idocc' is an *occurrence*, but we need to see the + -- unfolding in the *definition*; so look up in binder_set + refined_id = case lookupVarSet binder_set idocc of + Just id -> id + Nothing -> WARN( True, ppr idocc ) idocc + + unfold_env' = extendVarEnv unfold_env idocc (name',show_unfold) + referrer' | isExportedId refined_id = refined_id + | otherwise = referrer -- search (zip new_ids (repeat referrer') ++ rest) unfold_env' occ_env' @@ -631,45 +675,38 @@ chooseExternalIds hsc_env mod omit_prags binds let unfold_env' = extendVarEnv unfold_env id (name',False) tidy_internal ids unfold_env' occ_env' -addExternal :: Id -> CoreExpr -> ([Id],Bool) -addExternal id rhs = (new_needed_ids, show_unfold) +addExternal :: Bool -> Id -> ([Id],Bool) +addExternal expose_all id = (new_needed_ids, show_unfold) where new_needed_ids = unfold_ids ++ filter (\id -> isLocalId id && not (id `elemVarSet` unfold_set)) - (varSetElems worker_ids ++ - varSetElems spec_ids) -- XXX non-det ordering + (varSetElems spec_ids) -- XXX non-det ordering idinfo = idInfo id dont_inline = isNeverActive (inlinePragmaActivation (inlinePragInfo idinfo)) loop_breaker = isNonRuleLoopBreaker (occInfo idinfo) - bottoming_fn = isBottomingSig (newStrictnessInfo idinfo `orElse` topSig) + bottoming_fn = isBottomingSig (strictnessInfo idinfo `orElse` topSig) spec_ids = specInfoFreeVars (specInfo idinfo) - worker_info = workerInfo idinfo -- Stuff to do with the Id's unfolding - -- The simplifier has put an up-to-date unfolding - -- in the IdInfo, but the RHS will do just as well - unfolding = unfoldingInfo idinfo - rhs_is_small = not (neverUnfold unfolding) - -- We leave the unfolding there even if there is a worker -- In GHCI the unfolding is used by importers - -- When writing an interface file, we omit the unfolding - -- if there is a worker - show_unfold = not bottoming_fn && -- Not necessary - not dont_inline && - not loop_breaker && - rhs_is_small -- Small enough - - (unfold_set, unfold_ids) - | show_unfold = freeVarsInDepthFirstOrder rhs - | otherwise = (emptyVarSet, []) - - worker_ids = case worker_info of - HasWorker work_id _ -> unitVarSet work_id - _otherwise -> emptyVarSet - + show_unfold = isJust mb_unfold_ids + (unfold_set, unfold_ids) = mb_unfold_ids `orElse` (emptyVarSet, []) + + mb_unfold_ids :: Maybe (IdSet, [Id]) -- Nothing => don't unfold + mb_unfold_ids = case unfoldingInfo idinfo of + CoreUnfolding { uf_tmpl = unf_rhs, uf_guidance = guide } + | expose_all || -- expose_all says to expose all + -- unfoldings willy-nilly + not (bottoming_fn -- No need to inline bottom functions + || dont_inline -- Or ones that say not to + || loop_breaker -- Or that are loop breakers + || neverUnfoldGuidance guide) + -> Just (exprFvsInOrder unf_rhs) + DFunUnfolding _ ops -> Just (exprsFvsInOrder ops) + _ -> Nothing -- We want a deterministic free-variable list. exprFreeVars gives us -- a VarSet, which is in a non-deterministic order when converted to a @@ -678,11 +715,15 @@ addExternal id rhs = (new_needed_ids, show_unfold) -- -- Note [choosing external names] -freeVarsInDepthFirstOrder :: CoreExpr -> (VarSet, [Id]) -freeVarsInDepthFirstOrder e = - case dffvExpr e of - DFFV m -> case m emptyVarSet [] of - (set,ids,_) -> (set,ids) +exprFvsInOrder :: CoreExpr -> (VarSet, [Id]) +exprFvsInOrder e = run (dffvExpr e) + +exprsFvsInOrder :: [CoreExpr] -> (VarSet, [Id]) +exprsFvsInOrder es = run (mapM_ dffvExpr es) + +run :: DFFV () -> (VarSet, [Id]) +run (DFFV m) = case m emptyVarSet [] of + (set,ids,_) -> (set,ids) newtype DFFV a = DFFV (VarSet -> [Var] -> (VarSet,[Var],a)) @@ -802,15 +843,17 @@ tidyTopName mod nc_var maybe_ref occ_env id \end{code} \begin{code} -findExternalRules :: [CoreBind] - -> [CoreRule] -- Non-local rules (i.e. ones for imported fns) +findExternalRules :: Bool -- Omit pragmas + -> [CoreBind] + -> [CoreRule] -- Local rules for imported fns -> UnfoldEnv -- Ids that are exported, so we need their rules -> [CoreRule] -- The complete rules are gotten by combining - -- a) the non-local rules + -- a) local rules for imported Ids -- b) rules embedded in the top-level Ids -findExternalRules binds non_local_rules unfold_env - = filter (not . internal_rule) (non_local_rules ++ local_rules) +findExternalRules omit_prags binds imp_id_rules unfold_env + | omit_prags = [] + | otherwise = filterOut internal_rule (imp_id_rules ++ local_rules) where local_rules = [ rule | id <- bindersOfBinds binds, @@ -829,7 +872,14 @@ findExternalRules binds non_local_rules unfold_env | otherwise = False \end{code} - +Note [Which rules to expose] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +findExternalRules filters imp_rules to avoid binders that +aren't externally visible; but the externally-visible binders +are computed (by findExternalIds) assuming that all orphan +rules are externalised (see init_ext_ids in function +'search'). So in fact we may export more than we need. +(It's a sort of mutual recursion.) %************************************************************************ %* * @@ -924,20 +974,42 @@ tidyTopPair :: Bool -- show unfolding -- in the IdInfo of one early in the group tidyTopPair show_unfold rhs_tidy_env caf_info name' (bndr, rhs) - = (bndr', rhs') + = WARN( not _bottom_exposed, ppr bndr1 ) + (bndr1, rhs1) where - bndr' = mkGlobalId details name' ty' idinfo' + -- If the cheap-and-cheerful bottom analyser can see that + -- the RHS is bottom, it should jolly well be exposed + _bottom_exposed = case exprBotStrictness_maybe rhs of + Nothing -> True + Just (arity, _) -> appIsBottom str arity + where + str = strictnessInfo idinfo `orElse` topSig + + bndr1 = mkGlobalId details name' ty' idinfo' details = idDetails bndr -- Preserve the IdDetails ty' = tidyTopType (idType bndr) - rhs' = tidyExpr rhs_tidy_env rhs + rhs1 = tidyExpr rhs_tidy_env rhs idinfo = idInfo bndr idinfo' = tidyTopIdInfo (isExternalName name') - idinfo unfold_info worker_info - arity caf_info + idinfo unfold_info + arity caf_info + (occInfo idinfo) - unfold_info | show_unfold = mkTopUnfolding rhs' + unfold_info | show_unfold = tidyUnfolding rhs_tidy_env rhs1 (unfoldingInfo idinfo) | otherwise = noUnfolding - worker_info = tidyWorker rhs_tidy_env show_unfold (workerInfo idinfo) + -- NB: do *not* expose the worker if show_unfold is off, + -- because that means this thing is a loop breaker or + -- marked NOINLINE or something like that + -- This is important: if you expose the worker for a loop-breaker + -- then you can make the simplifier go into an infinite loop, because + -- in effect the unfolding is exposed. See Trac #1709 + -- + -- You might think that if show_unfold is False, then the thing should + -- not be w/w'd in the first place. But a legitimate reason is this: + -- the function returns bottom + -- In this case, show_unfold will be false (we don't expose unfoldings + -- for bottoming functions), but we might still have a worker/wrapper + -- split (see Note [Worker-wrapper for bottoming functions] in WorkWrap.lhs -- Usually the Id will have an accurate arity on it, because -- the simplifier has just run, but not always. @@ -961,50 +1033,50 @@ tidyTopPair show_unfold rhs_tidy_env caf_info name' (bndr, rhs) -- unfoldings, which are inside Ids imported by GHCi. Ditto RULES. -- CoreToStg makes use of this when constructing SRTs. tidyTopIdInfo :: Bool -> IdInfo -> Unfolding - -> WorkerInfo -> ArityInfo -> CafInfo + -> ArityInfo -> CafInfo -> OccInfo -> IdInfo -tidyTopIdInfo is_external idinfo unfold_info worker_info arity caf_info +tidyTopIdInfo is_external idinfo unfold_info arity caf_info occ_info | not is_external -- For internal Ids (not externally visible) = vanillaIdInfo -- we only need enough info for code generation -- Arity and strictness info are enough; -- c.f. CoreTidy.tidyLetBndr + `setOccInfo` robust_occ_info `setCafInfo` caf_info `setArityInfo` arity - `setAllStrictnessInfo` newStrictnessInfo idinfo + `setStrictnessInfo` strictnessInfo idinfo | otherwise -- Externally-visible Ids get the whole lot = vanillaIdInfo + `setOccInfo` robust_occ_info `setCafInfo` caf_info `setArityInfo` arity - `setAllStrictnessInfo` newStrictnessInfo idinfo + `setStrictnessInfo` strictnessInfo idinfo `setInlinePragInfo` inlinePragInfo idinfo `setUnfoldingInfo` unfold_info - `setWorkerInfo` worker_info -- NB: we throw away the Rules -- They have already been extracted by findExternalRules - - - ------------- Worker -------------- -tidyWorker :: TidyEnv -> Bool -> WorkerInfo -> WorkerInfo -tidyWorker _tidy_env _show_unfold NoWorker - = NoWorker -tidyWorker tidy_env show_unfold (HasWorker work_id wrap_arity) - | show_unfold = HasWorker (tidyVarOcc tidy_env work_id) wrap_arity - | otherwise = NoWorker - -- NB: do *not* expose the worker if show_unfold is off, - -- because that means this thing is a loop breaker or - -- marked NOINLINE or something like that - -- This is important: if you expose the worker for a loop-breaker - -- then you can make the simplifier go into an infinite loop, because - -- in effect the unfolding is exposed. See Trac #1709 - -- - -- You might think that if show_unfold is False, then the thing should - -- not be w/w'd in the first place. But a legitimate reason is this: - -- the function returns bottom - -- In this case, show_unfold will be false (we don't expose unfoldings - -- for bottoming functions), but we might still have a worker/wrapper - -- split (see Note [Worker-wrapper for bottoming functions] in WorkWrap.lhs + where + robust_occ_info = zapFragileOcc occ_info + -- It's important to keep loop-breaker information + -- when we are doing -fexpose-all-unfoldings + + + +------------ Unfolding -------------- +tidyUnfolding :: TidyEnv -> CoreExpr -> Unfolding -> Unfolding +tidyUnfolding tidy_env _ (DFunUnfolding con ids) + = DFunUnfolding con (map (tidyExpr tidy_env) ids) +tidyUnfolding tidy_env tidy_rhs unf@(CoreUnfolding { uf_tmpl = unf_rhs, uf_src = src }) + | isInlineRuleSource src + = unf { uf_tmpl = tidyExpr tidy_env unf_rhs, -- Preserves OccInfo + uf_src = tidyInl tidy_env src } + | otherwise + = mkTopUnfolding tidy_rhs +tidyUnfolding _ _ unf = unf + +tidyInl :: TidyEnv -> UnfoldingSource -> UnfoldingSource +tidyInl tidy_env (InlineWrapper w) = InlineWrapper (tidyVarOcc tidy_env w) +tidyInl _ inl_info = inl_info \end{code} %************************************************************************