X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FdeSugar%2FDsBinds.lhs;h=4db8dbf1a046a2f647bca0f4293762ad6d7ecf0e;hb=438596897ebbe25a07e1c82085cfbc5bdb00f09e;hp=0331a379832a4646311ec41a99218cdaeaf33bc6;hpb=f7ecf7234c224489be8a5e63fced903b655d92ee;p=ghc-hetmet.git diff --git a/ghc/compiler/deSugar/DsBinds.lhs b/ghc/compiler/deSugar/DsBinds.lhs index 0331a37..4db8dbf 100644 --- a/ghc/compiler/deSugar/DsBinds.lhs +++ b/ghc/compiler/deSugar/DsBinds.lhs @@ -1,5 +1,5 @@ % -% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996 +% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 % \section[DsBinds]{Pattern-matching bindings (HsBinds and MonoBinds)} @@ -8,580 +8,172 @@ in that the @Rec@/@NonRec@/etc structure is thrown away (whereas at lower levels it is preserved with @let@/@letrec@s). \begin{code} +module DsBinds ( dsMonoBinds ) where + #include "HsVersions.h" -module DsBinds ( dsBinds, dsInstBinds ) where -IMP_Ubiq() -IMPORT_DELOOPER(DsLoop) -- break dsExpr-ish loop +import {-# SOURCE #-} DsExpr( dsExpr ) import HsSyn -- lots of things - hiding ( collectBinders{-also in CoreSyn-} ) import CoreSyn -- lots of things -import TcHsSyn ( SYN_IE(TypecheckedHsBinds), SYN_IE(TypecheckedHsExpr), - SYN_IE(TypecheckedBind), SYN_IE(TypecheckedMonoBinds), - SYN_IE(TypecheckedPat) - ) -import DsHsSyn ( collectTypedBinders, collectTypedPatBinders ) - +import CoreUtils ( coreExprType ) +import TcHsSyn ( TypecheckedMonoBinds ) import DsMonad import DsGRHSs ( dsGuarded ) import DsUtils import Match ( matchWrapper ) -import CmdLineOpts ( opt_SccProfilingOn, opt_AutoSccsOnAllToplevs, opt_CompilingGhcInternals ) -import CostCentre ( mkAutoCC, IsCafCC(..), mkAllDictsCC, preludeDictsCostCentre ) -import Id ( idType, SYN_IE(DictVar), GenId ) -import ListSetOps ( minusList, intersectLists ) +import BasicTypes ( Module, RecFlag(..) ) +import CmdLineOpts ( opt_SccProfilingOn, opt_AutoSccsOnAllToplevs, + opt_AutoSccsOnExportedToplevs + ) +import CostCentre ( mkAutoCC, IsCafCC(..), mkAllDictsCC ) +import Id ( idType, Id ) +import VarEnv import Name ( isExported ) -import PprType ( GenType ) -import PprStyle ( PprStyle(..) ) -import Pretty ( ppShow ) -import Type ( mkTyVarTys, mkForAllTys, splitSigmaTy, - tyVarsOfType, tyVarsOfTypes, isDictTy +import Type ( mkTyVarTy, isDictTy, substTy ) -import TyVar ( tyVarSetToList, GenTyVar{-instance Eq-} ) -import Util ( isIn, panic{-, pprTrace ToDo:rm-} ) ---import PprCore--ToDo:rm ---import PprType ( GenTyVar ) --ToDo:rm ---import Usage--ToDo:rm ---import Unique--ToDo:rm +import TysWiredIn ( voidTy ) +import Outputable \end{code} %************************************************************************ %* * -\subsection[toplevel-and-regular-DsBinds]{Regular and top-level @dsBinds@} +\subsection[dsMonoBinds]{Desugaring a @MonoBinds@} %* * %************************************************************************ -Like @dsBinds@, @dsBind@ returns a @[CoreBinding]@, but it may be -that some of the binders are of unboxed type. This is sorted out when -the caller wraps the bindings round an expression. - -\begin{code} -dsBinds :: Bool -> TypecheckedHsBinds -> DsM [CoreBinding] -\end{code} - -All ``real'' bindings are expressed in terms of the -@AbsBinds@ construct, which is a massively-complicated ``shorthand'', -and its desugaring is the subject of section~9.1 in the static -semantics paper. - -(ToDo) For: -\begin{verbatim} -AbsBinds [a1, ... ,aj] -- type variables - [d1, ... ,dk] -- dict variables - [(l1,g1), ..., (lm,gm)] -- overloaded equivs [Id pairs] (later...) - [db1=..., ..., dbn=...] -- dict binds - [vb1=..., ..., vbm=...] -- val binds; note: vb_i = l_i -\end{verbatim} -we want to make, in the general case (non-Fozzie translation): -\begin{verbatim} - -- tupler-upper: - tup a1...aj d1...dk = - let in - let(rec) in (vb1,...,vbm) -- NB: == ... in (l1,...,lm) - - -- a bunch of selectors: - g1 a1...aj d1...dk = case (_tup a1...aj d1...dk) of (x1,x2,...,xm) -> x1 - ... - gm a1...aj d1...dk = case (_tup a1...aj d1...dk) of (x1,x2,...,xm) -> xm -\end{verbatim} -But there are lots of special cases. - - -%============================================== -\subsubsection{Structure cases} -%============================================== - \begin{code} -dsBinds auto_scc (BindWith _ _) = panic "dsBinds:BindWith" -dsBinds auto_scc EmptyBinds = returnDs [] -dsBinds auto_scc (SingleBind bind) = dsBind auto_scc [] [] id [] bind - -dsBinds auto_scc (ThenBinds binds_1 binds_2) - = andDs (++) (dsBinds auto_scc binds_1) (dsBinds auto_scc binds_2) -\end{code} - - -%============================================== -\subsubsection{AbsBind case: no overloading} -%============================================== - -Special case: no overloading. -\begin{verbatim} - x1 = e1 - x2 = e2 -\end{verbatim} -We abstract each wrt the type variables, giving -\begin{verbatim} - x1' = /\tyvars -> e1[x1' tyvars/x1, x2' tyvars/x2] - x2' = /\tyvars -> e2[x1' tyvars/x1, x2' tyvars/x2] -\end{verbatim} -There are some complications. - -(i) The @val_binds@ might mention variable not in @local_global_prs@. -In this case we need to make up new polymorphic versions of them. - -(ii) Exactly the same applies to any @inst_binds@ which may be -present. However, here we expect that mostly they will be simple constant -definitions, which don't mention the type variables at all, so making them -polymorphic is really overkill. @dsInstBinds@ deals with this case. - -\begin{code} -dsBinds auto_scc (AbsBinds tyvars [] local_global_prs inst_binds val_binds) - = mapDs mk_poly_private_binder private_binders - `thenDs` \ poly_private_binders -> - let - full_local_global_prs = (private_binders `zip` poly_private_binders) - ++ local_global_prs - in - listDs [ mkSatTyApp global tyvar_tys `thenDs` \ app -> - returnDs (local, app) - | (local,global) <- full_local_global_prs - ] `thenDs` \ env -> - --- pprTrace "AbsBinds1:" (ppr PprDebug env) $ - - extendEnvDs env ( - - dsInstBinds tyvars inst_binds `thenDs` \ (inst_bind_pairs, inst_env) -> - extendEnvDs inst_env ( - - dsBind auto_scc tyvars [] (lookupId full_local_global_prs) inst_bind_pairs val_binds - )) - where - -- "private_binders" is the list of binders in val_binds - -- which don't appear in the local_global_prs list - -- These only really show up in stuff produced from compiling - -- class and instance declarations. - -- We need to add suitable polymorphic versions of them to the - -- local_global_prs. - private_binders = binders `minusList` [local | (local,_) <- local_global_prs] - binders = collectTypedBinders val_binds - mk_poly_private_binder id = newSysLocalDs (mkForAllTys tyvars (idType id)) - - tyvar_tys = mkTyVarTys tyvars -\end{code} - - -%============================================== -\subsubsection{AbsBind case: overloading} -%============================================== - -If there is overloading we go for the general case. - -We want the global identifiers to be abstracted wrt all types and -dictionaries; and the local identifiers wrt the non-overloaded types. -That is, we try to avoid global scoping of type abstraction. Example - - f :: Eq a => a -> [(a,b)] -> b - f = ...f... - -Here, f is fully polymorphic in b. So we generate - - f ab d = let ...dict defns... - in - letrec f' b = ...(f' b)... - in f' b - -*Notice* that we don't clone type variables, and *do* make use of -shadowing. It is possible to do cloning, but it makes the code quite -a bit more complicated, and the simplifier will clone it all anyway. - -Why bother with this gloss? Because it makes it more likely that -the defn of f' can get floated out, notably if f gets specialised -to a particular type for a. - -\begin{code} -dsBinds auto_scc (AbsBinds all_tyvars dicts local_global_prs dict_binds val_binds) - = -- If there is any non-overloaded polymorphism, make new locals with - -- appropriate polymorphism - (if null non_overloaded_tyvars - then - -- No non-overloaded polymorphism, so stay with current envt - returnDs (id, [], []) - else - -- Some local, non-overloaded polymorphism - cloneTyVarsDs non_overloaded_tyvars `thenDs` \ local_tyvars -> - - mapDs mk_binder binders `thenDs` \ new_binders -> - let - old_new_pairs = binders `zip` new_binders - in - - listDs [ mkSatTyApp new non_ov_tyvar_tys `thenDs` \ app -> - returnDs (old, app) - | (old,new) <- old_new_pairs - ] `thenDs` \ extra_env -> - let - local_binds = [NonRec old app | (old,app) <- extra_env, old `is_elem` locals] - is_elem = isIn "dsBinds" - in - returnDs (lookupId old_new_pairs, extra_env, local_binds) - ) - `thenDs` \ (binder_subst_fn, local_env, local_binds) -> - --- pprTrace "AbsBinds:all:" (ppAbove (ppr PprDebug local_binds) (ppr PprDebug local_env)) $ - - extendEnvDs local_env ( - - dsInstBinds non_overloaded_tyvars dict_binds `thenDs` \ (inst_bind_pairs, inst_env) -> - - extendEnvDs inst_env ( - - dsBind auto_scc non_overloaded_tyvars [] binder_subst_fn inst_bind_pairs val_binds - )) `thenDs` \ core_binds -> +dsMonoBinds :: Bool -- False => don't (auto-)annotate scc on toplevs. + -> TypecheckedMonoBinds + -> [(Id,CoreExpr)] -- Put this on the end (avoid quadratic append) + -> DsM [(Id,CoreExpr)] -- Result - let - tuple_rhs = mkCoLetsAny core_binds ( - mkCoLetsAny local_binds ( - mkTupleExpr locals )) - in - mkTupleBind all_tyvars dicts local_global_prs tuple_rhs `thenDs` \ core_bind_prs -> +dsMonoBinds _ EmptyMonoBinds rest = returnDs rest - returnDs [ NonRec binder rhs | (binder,rhs) <- core_bind_prs ] - where - locals = [local | (local,global) <- local_global_prs] - non_ov_tyvar_tys = mkTyVarTys non_overloaded_tyvars +dsMonoBinds auto_scc (AndMonoBinds binds_1 binds_2) rest + = dsMonoBinds auto_scc binds_2 rest `thenDs` \ rest' -> + dsMonoBinds auto_scc binds_1 rest' - overloaded_tyvars = tyVarsOfTypes (map idType dicts) - non_overloaded_tyvars = all_tyvars `minusList` (tyVarSetToList{-????-} overloaded_tyvars) +dsMonoBinds _ (CoreMonoBind var core_expr) rest + = returnDs ((var, core_expr) : rest) - binders = collectTypedBinders val_binds - mk_binder id = newSysLocalDs (mkForAllTys non_overloaded_tyvars (idType id)) -\end{code} - -@mkSatTyApp id tys@ constructs an expression whose value is (id tys). -However, sometimes id takes more type args than are in tys, and the -specialiser hates that, so we have to eta expand, to -@(/\ a b -> id tys a b)@. +dsMonoBinds _ (VarMonoBind var expr) rest + = dsExpr expr `thenDs` \ core_expr -> -\begin{code} -mkSatTyApp :: Id -- Id to apply to the types - -> [Type] -- Types to apply it to - -> DsM CoreExpr + -- Dictionary bindings are always VarMonoBinds, so + -- we only need do this here + addDictScc var core_expr `thenDs` \ core_expr' -> -mkSatTyApp id [] = returnDs (Var id) + returnDs ((var, core_expr') : rest) -mkSatTyApp id tys - | null tvs - = returnDs ty_app -- Common case - | otherwise - = newTyVarsDs (drop (length tys) tvs) `thenDs` \ tyvars -> - returnDs (mkTyLam tyvars (mkTyApp ty_app (mkTyVarTys tyvars))) +dsMonoBinds auto_scc (FunMonoBind fun _ matches locn) rest + = putSrcLocDs locn $ + matchWrapper (FunMatch fun) matches error_string `thenDs` \ (args, body) -> + addAutoScc auto_scc (fun, mkLams args body) `thenDs` \ pair -> + returnDs (pair : rest) where - (tvs, theta, tau_ty) = splitSigmaTy (idType id) - ty_app = mkTyApp (Var id) tys -\end{code} - -There are several places where we encounter ``inst binds,'' -@(Id, TypecheckedHsExpr)@ pairs. Many of these are ``trivial'' binds -(a var to a var or literal), which we want to substitute away; so we -return both some desugared bindings {\em and} a substitution -environment for the subbed-away ones. - -These dictionary bindings are non-recursive, and ordered, so that -later ones may mention earlier ones, but not vice versa. + error_string = "function " ++ showSDoc (ppr fun) -\begin{code} -dsInstBinds :: [TyVar] -- Abstract wrt these - -> [(Id, TypecheckedHsExpr)] -- From AbsBinds - -> DsM ([(Id,CoreExpr)], -- Non-trivial bindings - [(Id,CoreExpr)]) -- Trivial ones to be substituted away - -do_nothing = ([], []) -- out here to avoid dsInstBinds CAF (sigh) -prel_dicts_cc = preludeDictsCostCentre False{-not dupd-} -- ditto - -dsInstBinds tyvars [] = returnDs do_nothing - -dsInstBinds tyvars ((inst, expr@(HsVar _)) : bs) - = dsExpr expr `thenDs` \ rhs -> - let -- Need to apply dsExpr to the variable in case it - -- has a substitution in the current environment - subst_item = (inst, rhs) +dsMonoBinds _ (PatMonoBind pat grhss_and_binds locn) rest + = putSrcLocDs locn $ + dsGuarded grhss_and_binds `thenDs` \ body_expr -> + mkSelectorBinds pat body_expr `thenDs` \ sel_binds -> + returnDs (sel_binds ++ rest) + + -- Common special case: no type or dictionary abstraction +dsMonoBinds auto_scc (AbsBinds [] [] exports binds) rest + = mapDs (addAutoScc auto_scc) [(global, Var local) | (_, global, local) <- exports] `thenDs` \ exports' -> + dsMonoBinds False binds (exports' ++ rest) + + -- Another common case: one exported variable + -- All non-recursive bindings come through this way +dsMonoBinds auto_scc (AbsBinds all_tyvars dicts [(tyvars, global, local)] binds) rest + = ASSERT( all (`elem` tyvars) all_tyvars ) + dsMonoBinds False binds [] `thenDs` \ core_prs -> + let + -- Always treat the binds as recursive, because the typechecker + -- makes rather mixed-up dictionary bindings + core_binds = [Rec core_prs] in - extendEnvDs [subst_item] ( - dsInstBinds tyvars bs - ) `thenDs` \ (binds, subst_env) -> - returnDs (binds, subst_item : subst_env) - -dsInstBinds tyvars ((inst, expr@(HsLit _)) : bs) - = dsExpr expr `thenDs` \ core_lit -> - let - subst_item = (inst, core_lit) + addAutoScc auto_scc (global, mkLams tyvars $ mkLams dicts $ + mkLets core_binds (Var local)) `thenDs` \ global' -> + returnDs (global' : rest) + +dsMonoBinds auto_scc (AbsBinds all_tyvars dicts exports binds) rest + = dsMonoBinds False binds [] `thenDs` \ core_prs -> + let + core_binds = [Rec core_prs] + + tup_expr = mkTupleExpr locals + tup_ty = coreExprType tup_expr + poly_tup_expr = mkLams all_tyvars $ mkLams dicts $ + mkLets core_binds tup_expr + locals = [local | (_, _, local) <- exports] + local_tys = map idType locals in - extendEnvDs [subst_item] ( - dsInstBinds tyvars bs - ) `thenDs` \ (binds, subst_env) -> - returnDs (binds, subst_item : subst_env) - -dsInstBinds tyvars ((inst, expr) : bs) - | null abs_tyvars - = dsExpr expr `thenDs` \ core_expr -> - ds_dict_cc core_expr `thenDs` \ dict_expr -> - dsInstBinds tyvars bs `thenDs` \ (core_rest, subst_env) -> - returnDs ((inst, dict_expr) : core_rest, subst_env) - - | otherwise - = -- Obscure case. - -- The inst mentions the type vars wrt which we are abstracting, - -- so we have to invent a new polymorphic version, and substitute - -- appropriately. - -- This can occur in, for example: - -- leftPoll :: [FeedBack a] -> FeedBack a - -- leftPoll xs = take poll xs - -- Here there is an instance of take at the type of elts of xs, - -- as well as the type of poll. - - dsExpr expr `thenDs` \ core_expr -> - ds_dict_cc core_expr `thenDs` \ dict_expr -> - newSysLocalDs poly_inst_ty `thenDs` \ poly_inst_id -> + newSysLocalDs (coreExprType poly_tup_expr) `thenDs` \ poly_tup_id -> let - subst_item = (inst, mkTyApp (Var poly_inst_id) abs_tys) + dict_args = map Var dicts + + mk_bind (tyvars, global, local) n -- locals !! n == local + = -- Need to make fresh locals to bind in the selector, because + -- some of the tyvars will be bound to voidTy + newSysLocalsDs (map (substTy env) local_tys) `thenDs` \ locals' -> + newSysLocalDs (substTy env tup_ty) `thenDs` \ tup_id -> + addAutoScc auto_scc + (global, mkLams tyvars $ mkLams dicts $ + mkTupleSelector locals' (locals' !! n) tup_id $ + mkApps (mkTyApps (Var poly_tup_id) ty_args) dict_args) + where + mk_ty_arg all_tyvar | all_tyvar `elem` tyvars = mkTyVarTy all_tyvar + | otherwise = voidTy + ty_args = map mk_ty_arg all_tyvars + env = all_tyvars `zipVarEnv` ty_args in - extendEnvDs [subst_item] ( - dsInstBinds tyvars bs - ) `thenDs` \ (core_rest, subst_env) -> - returnDs ((poly_inst_id, mkTyLam abs_tyvars dict_expr) : core_rest, - subst_item : subst_env) - where - inst_ty = idType inst - abs_tyvars = tyVarSetToList{-???sigh-} (tyVarsOfType inst_ty) `intersectLists` tyvars - abs_tys = mkTyVarTys abs_tyvars - poly_inst_ty = mkForAllTys abs_tyvars inst_ty - - ------------------------ - -- Wrap a desugared expression in `_scc_ "DICT" ' if - -- appropriate. Uses "inst"'s type. - - -- if profiling, wrap the dict in "_scc_ DICT ": - ds_dict_cc expr - | not ( opt_SccProfilingOn || opt_AutoSccsOnAllToplevs) - -- the latter is so that -unprof-auto-scc-all adds dict sccs - || not (isDictTy inst_ty) - = returnDs expr -- that's easy: do nothing - - | opt_CompilingGhcInternals - = returnDs (SCC prel_dicts_cc expr) - - | otherwise - = getModuleAndGroupDs `thenDs` \ (mod, grp) -> - - -- ToDo: do -dicts-all flag (mark dict things with individual CCs) - - returnDs (SCC (mkAllDictsCC mod grp False) expr) -\end{code} - -%************************************************************************ -%* * -\subsection[dsBind]{Desugaring a @Bind@} -%* * -%************************************************************************ - -Like @dsBinds@, @dsBind@ returns a @[CoreBinding]@, but it may be that -some of the binders are of unboxed type. - -For an explanation of the first three args, see @dsMonoBinds@. - -\begin{code} -dsBind :: Bool -- Add auto sccs to binds - -> [TyVar] -> [DictVar] -- Abstract wrt these - -> (Id -> Id) -- Binder substitution - -> [(Id,CoreExpr)] -- Inst bindings already dealt with - -> TypecheckedBind - -> DsM [CoreBinding] - -dsBind auto_scc tyvars dicts binder_subst inst_bind_pairs EmptyBind - = returnDs [NonRec binder rhs | (binder,rhs) <- inst_bind_pairs] - -dsBind auto_scc tyvars dicts binder_subst inst_bind_pairs (NonRecBind monobinds) - = dsMonoBinds auto_scc False tyvars dicts binder_subst monobinds `thenDs` \ val_bind_pairs -> - returnDs [NonRec binder rhs | (binder,rhs) <- inst_bind_pairs ++ val_bind_pairs] - -dsBind auto_scc tyvars dicts binder_subst inst_bind_pairs (RecBind monobinds) - = dsMonoBinds auto_scc True tyvars dicts binder_subst monobinds `thenDs` \ val_bind_pairs -> - returnDs [Rec (inst_bind_pairs ++ val_bind_pairs)] + zipWithDs mk_bind exports [0..] `thenDs` \ export_binds -> + -- don't scc (auto-)annotate the tuple itself. + returnDs ((poly_tup_id, poly_tup_expr) : (export_binds ++ rest)) \end{code} %************************************************************************ %* * -\subsection[dsMonoBinds]{Desugaring a @MonoBinds@} +\subsection[addAutoScc]{Adding automatic sccs} %* * %************************************************************************ -@dsMonoBinds@ transforms @TypecheckedMonoBinds@ into @CoreBinds@. -In addition to desugaring pattern matching, @dsMonoBinds@ takes -a list of type variables and dicts, and adds abstractions for these -to the front of every binding. That requires that the -binders be altered too (their type has changed, -so @dsMonoBinds@ also takes a function which maps binders into binders. -This mapping gives the binder the correct new type. - -Remember, there's also a substitution in the monad which maps occurrences -of these binders into applications of the new binder to suitable type variables -and dictionaries. - -\begin{code} -dsMonoBinds :: Bool -- True <=> add auto sccs - -> Bool -- True <=> recursive binding group - -> [TyVar] -> [DictVar] -- Abstract wrt these - -> (Id -> Id) -- Binder substitution - -> TypecheckedMonoBinds - -> DsM [(Id,CoreExpr)] -\end{code} - - - -%============================================== -\subsubsection{Structure cases} -%============================================== - -\begin{code} -dsMonoBinds auto_scc is_rec tyvars dicts binder_subst EmptyMonoBinds = returnDs [] - -dsMonoBinds auto_scc is_rec tyvars dicts binder_subst (AndMonoBinds binds_1 binds_2) - = andDs (++) (dsMonoBinds auto_scc is_rec tyvars dicts binder_subst binds_1) - (dsMonoBinds auto_scc is_rec tyvars dicts binder_subst binds_2) -\end{code} - - -%============================================== -\subsubsection{Simple base cases: function and variable bindings} -%============================================== - -\begin{code} -dsMonoBinds auto_scc is_rec tyvars dicts binder_subst (VarMonoBind var expr) - = dsExpr expr `thenDs` \ core_expr -> - doSccAuto auto_scc [var] core_expr `thenDs` \ sccd_core_expr -> - returnDs [(binder_subst var, mkLam tyvars dicts sccd_core_expr)] - -dsMonoBinds auto_scc is_rec tyvars dicts binder_subst (FunMonoBind fun _ matches locn) - = putSrcLocDs locn $ - let - new_fun = binder_subst fun - error_string = "function " ++ showForErr fun - in - matchWrapper (FunMatch fun) matches error_string `thenDs` \ (args, body) -> - doSccAuto auto_scc [fun] body `thenDs` \ sccd_body -> - returnDs [(new_fun, - mkLam tyvars (dicts ++ args) sccd_body)] - -dsMonoBinds auto_scc is_rec tyvars dicts binder_subst (PatMonoBind (VarPat v) grhss_and_binds locn) - = putSrcLocDs locn $ - dsGuarded grhss_and_binds `thenDs` \ body_expr -> - doSccAuto auto_scc [v] body_expr `thenDs` \ sccd_body_expr -> - returnDs [(binder_subst v, mkLam tyvars dicts sccd_body_expr)] -\end{code} - -%============================================== -\subsubsection{The general base case} -%============================================== - -Now the general case of a pattern binding. The monomorphism restriction -should ensure that if there is a non-simple pattern binding in the -group, then there is no overloading involved, so the dictionaries should -be empty. (Simple pattern bindings were handled above.) -First, the paranoia check. - \begin{code} -dsMonoBinds auto_scc is_rec tyvars (_:_) binder_subst (PatMonoBind pat grhss_and_binds locn) - = panic "Non-empty dict list in for pattern binding" -\end{code} - -We handle three cases for the binding - pat = rhs - -\begin{description} -\item[pat has no binders.] -Then all this is dead code and we return an empty binding. - -\item[pat has exactly one binder, v.] -Then we can transform to: -\begin{verbatim} - v' = /\ tyvars -> case rhs of { pat -> v } -\end{verbatim} -where \tr{v'} is gotten by looking up \tr{v} in the \tr{binder_subst}. - -\item[pat has more than one binder.] -Then we transform to: -\begin{verbatim} - t = /\ tyvars -> case rhs of { pat -> (v1, ..., vn) } - - vi = /\ tyvars -> case (t tyvars) of { (v1, ..., vn) -> vi } -\end{verbatim} -\end{description} - -\begin{code} -dsMonoBinds auto_scc is_rec tyvars [] binder_subst (PatMonoBind pat grhss_and_binds locn) - = putSrcLocDs locn $ - - dsGuarded grhss_and_binds `thenDs` \ body_expr -> - doSccAuto auto_scc pat_binders body_expr `thenDs` \ sccd_body_expr -> - -{- KILLED by Sansom. 95/05 - -- make *sure* there are no primitive types in the pattern - if any_con_w_prim_arg pat then - error ( "ERROR: Pattern-bindings cannot involve unboxed/primitive types!\n\t" - ++ (ppShow 80 (ppr PprForUser pat)) ++ "\n" - ++ "(We apologise for not reporting this more `cleanly')\n" ) - - -- Check whether the pattern already is a simple tuple; if so, - -- we can just use the rhs directly - else --} --- pprTrace "dsMonoBinds:PatMonoBind:" (ppr PprDebug sccd_body_expr) $ - - mkSelectorBinds tyvars pat - [(binder, binder_subst binder) | binder <- pat_binders] - sccd_body_expr - where - pat_binders = collectTypedPatBinders pat - -- NB For a simple tuple pattern, these binders - -- will appear in the right order! +addAutoScc :: Bool -- if needs be, decorate toplevs? + -> (Id, CoreExpr) + -> DsM (Id, CoreExpr) + +addAutoScc auto_scc_candidate pair@(bndr, core_expr) + | auto_scc_candidate && worthSCC core_expr && + (opt_AutoSccsOnAllToplevs || (isExported bndr && opt_AutoSccsOnExportedToplevs)) + = getModuleAndGroupDs `thenDs` \ (mod,grp) -> + returnDs (bndr, Note (SCC (mkAutoCC bndr mod grp IsNotCafCC)) core_expr) + | otherwise + = returnDs pair + +worthSCC (Note (SCC _) _) = False +worthSCC (Con _ _) = False +worthSCC core_expr = True \end{code} -Wild-card patterns could be made acceptable here, but it involves some -extra work to benefit only rather unusual constructs like -\begin{verbatim} - let (_,a,b) = ... in ... -\end{verbatim} -Better to extend the whole thing for any irrefutable constructor, at least. - -%************************************************************************ -%* * -\subsection[doSccAuto]{Adding automatic sccs} -%* * -%************************************************************************ +If profiling and dealing with a dict binding, wrap the dict in "_scc_ DICT ": \begin{code} -doSccAuto :: Bool -> [Id] -> CoreExpr -> DsM CoreExpr - -doSccAuto False binders core_expr - = returnDs core_expr - -doSccAuto True [] core_expr -- no binders - = returnDs core_expr - -doSccAuto True _ core_expr@(SCC _ _) -- already sccd - = returnDs core_expr - -doSccAuto True _ core_expr@(Con _ _) -- dont bother for simple Con - = returnDs core_expr - -doSccAuto True binders core_expr - = let - scc_all = opt_AutoSccsOnAllToplevs - scc_export = not (null export_binders) +addDictScc var rhs + | not ( opt_SccProfilingOn || opt_AutoSccsOnAllToplevs) + -- the latter is so that -unprof-auto-scc-all adds dict sccs + || not (isDictTy (idType var)) + = returnDs rhs -- That's easy: do nothing - export_binders = filter isExported binders + | otherwise + = getModuleAndGroupDs `thenDs` \ (mod, grp) -> - scc_binder = head (if scc_all then binders else export_binders) - in - if scc_all || scc_export then - getModuleAndGroupDs `thenDs` \ (mod,grp) -> - returnDs (SCC (mkAutoCC scc_binder mod grp IsNotCafCC) core_expr) - else - returnDs core_expr + -- ToDo: do -dicts-all flag (mark dict things with individual CCs) + returnDs (Note (SCC (mkAllDictsCC mod grp False)) rhs) \end{code}