InstDecl(..), HsType(..), hsTyVarNames, getBangType
)
import HsImpExp ( ImportDecl(..) )
-import RdrHsSyn ( RdrNameHsDecl, RdrNameTyClDecl, RdrNameInstDecl )
-import RnHsSyn ( RenamedHsDecl, extractHsTyNames, extractHsCtxtTyNames, tyClDeclFVs )
+import RdrHsSyn ( RdrNameTyClDecl, RdrNameInstDecl, RdrNameRuleDecl )
+import RnHsSyn ( RenamedHsDecl, RenamedTyClDecl,
+ extractHsTyNames, extractHsCtxtTyNames,
+ tyClDeclFVs, ruleDeclFVs, instDeclFVs
+ )
import RnHiFiles ( tryLoadInterface, loadHomeInterface, loadInterface,
loadOrphanModules
)
-import RnSource ( rnTyClDecl, rnDecl )
+import RnSource ( rnTyClDecl, rnInstDecl, rnIfaceRuleDecl )
import RnEnv
import RnMonad
import Id ( idType )
-import DataCon ( classDataCon, dataConId )
import Type ( namesOfType )
import TyCon ( isSynTyCon, getSynTyConDefn )
import Name ( Name {-instance NamedThing-}, nameOccName,
nameModule, isLocalName, nameUnique,
- NamedThing(..),
+ NamedThing(..)
)
-import Name ( elemNameEnv )
+import Name ( elemNameEnv, delFromNameEnv )
import Module ( Module, ModuleEnv,
moduleName, isModuleInThisPackage,
ModuleName, WhereFrom(..),
slurpSourceRefs source_binders source_fvs `thenRn` \ (decls, needed) ->
-- Then get everything else
- closeDecls decls needed `thenRn` \ decls1 ->
-
- -- Finally, get any deferred data type decls
- slurpDeferredDecls decls1 `thenRn` \ final_decls ->
-
- returnRn final_decls
+ closeDecls decls needed
-------------------------------------------------------
-- and the instance decls
-- The outer loop is needed because consider
- -- instance Foo a => Baz (Maybe a) where ...
- -- It may be that @Baz@ and @Maybe@ are used in the source module,
- -- but not @Foo@; so we need to chase @Foo@ too.
- --
- -- We also need to follow superclass refs. In particular, 'chasing @Foo@' must
- -- include actually getting in Foo's class decl
- -- class Wib a => Foo a where ..
- -- so that its superclasses are discovered. The point is that Wib is a gate too.
- -- We do this for tycons too, so that we look through type synonyms.
go_outer decls fvs all_gates []
= returnRn (decls, fvs)
go_outer decls fvs all_gates refs -- refs are not necessarily slurped yet
= traceRn (text "go_outer" <+> ppr refs) `thenRn_`
+ getImportedInstDecls all_gates `thenRn` \ inst_decls ->
foldlRn go_inner (decls, fvs, emptyFVs) refs `thenRn` \ (decls1, fvs1, gates1) ->
- getImportedInstDecls (all_gates `plusFV` gates1) `thenRn` \ inst_decls ->
- rnInstDecls decls1 fvs1 gates1 inst_decls `thenRn` \ (decls2, fvs2, gates2) ->
+ rnIfaceInstDecls decls1 fvs1 gates1 inst_decls `thenRn` \ (decls2, fvs2, gates2) ->
go_outer decls2 fvs2 (all_gates `plusFV` gates2)
(nameSetToList (gates2 `minusNameSet` all_gates))
-- Knock out the all_gates because even if we don't slurp any new
case import_result of
AlreadySlurped -> returnRn (decls, fvs, gates)
InTypeEnv ty_thing -> returnRn (decls, fvs, gates `plusFV` getWiredInGates ty_thing)
- Deferred -> returnRn (decls, fvs, gates `addOneFV` wanted_name) -- It's a type constructor
HereItIs decl -> rnIfaceTyClDecl decl `thenRn` \ (new_decl, fvs1) ->
returnRn (TyClD new_decl : decls,
fvs1 `plusFV` fvs,
gates `plusFV` getGates source_fvs new_decl)
-
-rnInstDecls decls fvs gates []
- = returnRn (decls, fvs, gates)
-rnInstDecls decls fvs gates (d:ds)
- = rnIfaceDecl d `thenRn` \ (new_decl, fvs1) ->
- rnInstDecls (new_decl:decls)
- (fvs1 `plusFV` fvs)
- (gates `plusFV` getInstDeclGates new_decl)
- ds
\end{code}
= getImportedRules `thenRn` \ rule_decls ->
case rule_decls of
[] -> returnRn decls -- No new rules, so we are done
- other -> rnIfaceDecls decls emptyFVs rule_decls `thenRn` \ (decls1, needed1) ->
- closeDecls decls1 needed1
+ other -> rnIfaceDecls rnIfaceRuleDecl rule_decls `thenRn` \ rule_decls' ->
+ closeDecls (map RuleD rule_decls' ++ decls)
+ (plusFVs (map ruleDeclFVs rule_decls'))
-------------------------------------------------------
-------------------------------------------------------
-rnIfaceDecls :: [RenamedHsDecl] -> FreeVars
- -> [(Module, RdrNameHsDecl)]
- -> RnM d ([RenamedHsDecl], FreeVars)
-rnIfaceDecls decls fvs [] = returnRn (decls, fvs)
-rnIfaceDecls decls fvs (d:ds) = rnIfaceDecl d `thenRn` \ (new_decl, fvs1) ->
- rnIfaceDecls (new_decl:decls) (fvs1 `plusFV` fvs) ds
-
-rnIfaceDecl (mod, decl) = initIfaceRnMS mod (rnDecl decl)
+rnIfaceDecls rn decls = mapRn (rnIfaceDecl rn) decls
+rnIfaceDecl rn (mod, decl) = initIfaceRnMS mod (rn decl)
+
+rnIfaceInstDecls decls fvs gates inst_decls
+ = rnIfaceDecls rnInstDecl inst_decls `thenRn` \ inst_decls' ->
+ returnRn (map InstD inst_decls' ++ decls,
+ fvs `plusFV` plusFVs (map instDeclFVs inst_decls'),
+ gates `plusFV` plusFVs (map getInstDeclGates inst_decls'))
+
rnIfaceTyClDecl (mod, decl) = initIfaceRnMS mod (rnTyClDecl decl) `thenRn` \ decl' ->
returnRn (decl', tyClDeclFVs decl')
\end{code}
= getIfacesRn `thenRn` \ ifaces ->
returnRn (iSlurp ifaces)
-recordSlurp ifaces@(Ifaces { iSlurp = slurped_names, iVSlurp = (imp_mods, imp_names) })
+recordSlurp ifaces@(Ifaces { iDecls = (decls_map, n_slurped),
+ iSlurp = slurped_names,
+ iVSlurp = (imp_mods, imp_names) })
avail
= ASSERT2( not (isLocalName (availName avail)), ppr avail )
- ifaces { iSlurp = new_slurped_names, iVSlurp = new_vslurp }
+ ifaces { iDecls = (decls_map', n_slurped+1),
+ iSlurp = new_slurped_names,
+ iVSlurp = new_vslurp }
where
- main_name = availName avail
- mod = nameModule main_name
+ decls_map' = foldl delFromNameEnv decls_map (availNames avail)
+ main_name = availName avail
+ mod = nameModule main_name
new_slurped_names = addAvailToNameSet slurped_names avail
new_vslurp | isModuleInThisPackage mod = (imp_mods, addOneToNameSet imp_names main_name)
| otherwise = (extendModuleSet imp_mods mod, imp_names)
%*********************************************************
%* *
-\subsection{Deferred declarations}
-%* *
-%*********************************************************
-
-The idea of deferred declarations is this. Suppose we have a function
- f :: T -> Int
- data T = T1 A | T2 B
- data A = A1 X | A2 Y
- data B = B1 P | B2 Q
-Then we don't want to load T and all its constructors, and all
-the types those constructors refer to, and all the types *those*
-constructors refer to, and so on. That might mean loading many more
-interface files than is really necessary. So we 'defer' loading T.
-
-But f might be strict, and the calling convention for evaluating
-values of type T depends on how many constructors T has, so
-we do need to load T, but not the full details of the type T.
-So we load the full decl for T, but only skeleton decls for A and B:
- f :: T -> Int
- data T = {- 2 constructors -}
-
-Whether all this is worth it is moot.
-
-\begin{code}
-slurpDeferredDecls :: [RenamedHsDecl] -> RnMG [RenamedHsDecl]
-slurpDeferredDecls decls = returnRn decls
-
-{- OMIT FOR NOW
-slurpDeferredDecls :: [RenamedHsDecl] -> RnMG [RenamedHsDecl]
-slurpDeferredDecls decls
- = getDeferredDecls `thenRn` \ def_decls ->
- rnIfaceDecls decls emptyFVs (map stripDecl def_decls) `thenRn` \ (decls1, fvs) ->
- ASSERT( isEmptyFVs fvs )
- returnRn decls1
-
-stripDecl (mod, TyClD (TyData dt _ tc tvs _ nconstrs _ loc name1 name2))
- = (mod, TyClD (TyData dt [] tc tvs [] nconstrs Nothing loc
- name1 name2))
- -- Nuke the context and constructors
- -- But retain the *number* of constructors!
- -- Also the tvs will have kinds on them.
--}
-\end{code}
-
-
-%*********************************************************
-%* *
\subsection{Extracting the `gates'}
%* *
%*********************************************************
instance (..) => C (T1 a) (T2 b) where ...
-is only useful if C, T1 and T2 are all available. So we keep
+is only useful if C, T1 and T2 are all "available". So we keep
instance decls that have been parsed from .hi files, but not yet
slurped in, in a pool called the 'gated instance pool'.
Each has its set of 'gates': {C, T1, T2} in the above example.
-THE GATING INVARIANT
+More precisely, the gates of a module are the types and classes
+that are mentioned in:
+
+ a) the source code
+ b) the type of an Id that's mentioned in the source code
+ [includes constructors and selectors]
+ c) the RHS of a type synonym that is a gate
+ d) the superclasses of a class that is a gate
+ e) the context of an instance decl that is slurped in
+
+We slurp in an instance decl from the gated instance pool iff
+
+ all its gates are either in the gates of the module,
+ or are a previously-loaded class.
- *All* the instances whose gates are entirely in the stuff that's
- already been through the type checker (i.e. are already in the
- Persistent Type Environment or Home Symbol Table) have already been
- slurped in, and are no longer in the gated instance pool.
+The latter constraint is because there might have been an instance
+decl slurped in during an earlier compilation, like this:
-Hence, when we read a new module, we see what new gates we have,
-and let in any instance decls whose gates are
- either in the new gates,
- or in the HST/PTE
+ instance Foo a => Baz (Maybe a) where ...
-An earlier optimisation: now infeasible
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+In the module being compiled we might need (Baz (Maybe T)), where T
+is defined in this module, and hence we need (Foo T). So @Foo@ becomes
+a gate. But there's no way to 'see' that, so we simply treat all
+previously-loaded classes as gates.
+
+Consructors and class operations
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
When we import a declaration like
-\begin{verbatim}
+
data T = T1 Wibble | T2 Wobble
-\end{verbatim}
+
we don't want to treat @Wibble@ and @Wobble@ as gates {\em unless}
-@T1@, @T2@ respectively are mentioned by the user program. If only
+@T1@, @T2@ respectively are mentioned by the user program. If only
@T@ is mentioned we want only @T@ to be a gate; that way we don't suck
in useless instance decls for (say) @Eq Wibble@, when they can't
possibly be useful.
-BUT, I can't see how to do this and still maintain the GATING INVARIANT.
-So I've simply ditched the optimisation to get things working.
-
-
-
+And that's just what (b) says: we only treat T1's type as a gate if
+T1 is mentioned. getGates, which deals with decls we are slurping in,
+has to be a bit careful, because a mention of T1 will slurp in T's whole
+declaration.
+-----------------------------
@getGates@ takes a newly imported (and renamed) decl, and the free
vars of the source program, and extracts from the decl the gate names.
\begin{code}
getGates :: FreeVars -- Things mentioned in the source program
- -> RenamedHsDecl
+ -> RenamedTyClDecl
-> FreeVars
-get_gates source_fvs decl = get_gates (\n -> True) decl
- -- We'd use (\n -> n `elemNameSet` source_fvs)
- -- if we were using the 'earlier optimisation above
+getGates source_fvs decl
+ = get_gates (\n -> n `elemNameSet` source_fvs) decl
get_gates is_used (IfaceSig _ ty _ _)
= extractHsTyNames ty
get_bang bty = extractHsTyNames (getBangType bty)
\end{code}
-@getWiredInGates@ is just like @getGates@, but it sees a wired-in @Name@
-rather than a declaration.
+@getWiredInGates@ is just like @getGates@, but it sees a previously-loaded
+thing rather than a declaration.
\begin{code}
getWiredInGates :: TyThing -> FreeVars
-- The TyThing is one that we already have in our type environment, either
-- a) because the TyCon or Id is wired in, or
-- b) from a previous compile
--- Either way, we might have instance decls in the (persistend) collection
+-- Either way, we might have instance decls in the (persistent) collection
-- of parsed-but-not-slurped instance decls that should be slurped in.
-- This might be the first module that mentions both the type and the class
-- for that instance decl, even though both the type and the class were
-- mentioned in other modules, and hence are in the type environment
-getWiredInGates (AnId the_id) = getWiredInGates_s (namesOfType (idType the_id))
-getWiredInGates (AClass cl) = namesOfType (idType (dataConId (classDataCon cl))) -- Cunning
+getWiredInGates (AnId the_id) = namesOfType (idType the_id)
+getWiredInGates (AClass cl) = emptyFVs -- The superclasses must also be previously
+ -- loaded, and hence are automatically gates
getWiredInGates (ATyCon tc)
- | isSynTyCon tc = getWiredInGates_s (delListFromNameSet (namesOfType ty) (map getName tyvars))
+ | isSynTyCon tc = delListFromNameSet (namesOfType ty) (map getName tyvars)
| otherwise = unitFV (getName tc)
where
(tyvars,ty) = getSynTyConDefn tc
-getWiredInGates_s names = foldr (plusFV . getWiredInGates) emptyFVs (nameSetToList names)
+getInstDeclGates (InstDecl inst_ty _ _ _ _) = extractHsTyNames inst_ty
\end{code}
\begin{code}
-getInstDeclGates (InstD (InstDecl inst_ty _ _ _ _)) = extractHsTyNames inst_ty
-getInstDeclGates other = emptyFVs
-\end{code}
-
-\begin{code}
-getImportedInstDecls :: NameSet -> RnMG [(Module,RdrNameHsDecl)]
+getImportedInstDecls :: NameSet -> RnMG [(Module,RdrNameInstDecl)]
getImportedInstDecls gates
= -- First, load any orphan-instance modules that aren't aready loaded
-- Orphan-instance modules are recorded in the module dependecnies
where
gate_list = nameSetToList gates
-ppr_brief_inst_decl (mod, InstD (InstDecl inst_ty _ _ _ _))
+ppr_brief_inst_decl (mod, InstDecl inst_ty _ _ _ _)
= case inst_ty of
HsForAllTy _ _ tau -> ppr tau
other -> ppr inst_ty
-getImportedRules :: RnMG [(Module,RdrNameHsDecl)]
+getImportedRules :: RnMG [(Module,RdrNameRuleDecl)]
getImportedRules
| opt_IgnoreIfacePragmas = returnRn []
| otherwise
text "Slurped" <+> int (length decls) <+> text "rules"]) `thenRn_`
returnRn decls
-selectGated gates lookup decl_bag
+selectGated gates lookup (decl_bag, n_slurped)
-- Select only those decls whose gates are *all* in 'gates'
- -- or are in the range of lookup
+ -- or are a class in 'lookup'
#ifdef DEBUG
| opt_NoPruneDecls -- Just to try the effect of not gating at all
- = (foldrBag (\ (_,d) ds -> d:ds) [] decl_bag, emptyBag) -- Grab them all
+ = let
+ decls = foldrBag (\ (_,d) ds -> d:ds) [] decl_bag -- Grab them all
+ in
+ (decls, (emptyBag, n_slurped + length decls))
| otherwise
#endif
- = foldrBag select ([], emptyBag) decl_bag
+ = case foldrBag select ([], emptyBag) decl_bag of
+ (decls, new_bag) -> (decls, (new_bag, n_slurped + length decls))
where
- available n = n `elemNameSet` gates || maybeToBool (lookup n)
+ available n = n `elemNameSet` gates
+ || case lookup n of { Just (AClass c) -> True; other -> False }
+
select (reqd, decl) (yes, no)
| all available reqd = (decl:yes, no)
| otherwise = (yes, (reqd,decl) `consBag` no)
data ImportDeclResult
= AlreadySlurped
| InTypeEnv TyThing
- | Deferred
| HereItIs (Module, RdrNameTyClDecl)
importDecl name
-> -- When we find a wired-in name we must load its home
-- module so that we find any instance decls lurking therein
loadHomeInterface wi_doc name `thenRn_`
- returnRn (InTypeEnv (getWiredInGates ty_thing))
+ returnRn (InTypeEnv ty_thing)
| otherwise
- -> returnRn (InTypeEnv ty_thing) ;
+ -> returnRn (InTypeEnv ty_thing) ;
Nothing ->
getIfacesRn `thenRn` \ ifaces ->
-- STEP 5: Get the declaration out
- case lookupNameEnv (iDecls ifaces) name of
+ let
+ (decls_map, _) = iDecls ifaces
+ in
+ case lookupNameEnv decls_map name of
Just (avail,_,decl)
-> setIfacesRn (recordSlurp ifaces avail) `thenRn_`
returnRn (HereItIs decl)
wi_doc = ptext SLIT("need home module for wired in thing") <+> ppr name
nd_doc = ptext SLIT("need decl for") <+> ppr name
-
-{- OMIT DEFERRED STUFF FOR NOW, TILL GHCI WORKS
- Just (version, avail, is_tycon_name, decl@(_, TyClD (TyData DataType _ _ _ _ ncons _ _ _ _)))
- -- This case deals with deferred import of algebraic data types
-
- | not opt_NoPruneTyDecls
-
- && (opt_IgnoreIfacePragmas || ncons > 1)
- -- We only defer if imported interface pragmas are ingored
- -- or if it's not a product type.
- -- Sole reason: The wrapper for a strict function may need to look
- -- inside its arg, and hence need to see its arg type's constructors.
-
- && not (getUnique tycon_name `elem` cCallishTyKeys)
- -- Never defer ccall types; we have to unbox them,
- -- and importing them does no harm
-
-
- -> -- OK, so we're importing a deferrable data type
- if needed_name == tycon_name
- -- The needed_name is the TyCon of a data type decl
- -- Record that it's slurped, put it in the deferred set
- -- and don't return a declaration at all
- setIfacesRn (recordSlurp (ifaces {iDeferred = iDeferred ifaces
- `addOneToNameSet` tycon_name})
- version (AvailTC needed_name [needed_name])) `thenRn_`
- returnRn Deferred
-
- else
- -- The needed name is a constructor of a data type decl,
- -- getting a constructor, so remove the TyCon from the deferred set
- -- (if it's there) and return the full declaration
- setIfacesRn (recordSlurp (ifaces {iDeferred = iDeferred ifaces
- `delFromNameSet` tycon_name})
- version avail) `thenRn_`
- returnRn (HereItIs decl)
- where
- tycon_name = availName avail
--}
-
-{- OMIT FOR NOW
-getDeferredDecls :: RnMG [(Module, RdrNameHsDecl)]
-getDeferredDecls
- = getIfacesRn `thenRn` \ ifaces ->
- let
- decls_map = iDecls ifaces
- deferred_names = nameSetToList (iDeferred ifaces)
- get_abstract_decl n = case lookupNameEnv decls_map n of
- Just (_, _, _, decl) -> decl
- in
- traceRn (sep [text "getDeferredDecls", nest 4 (fsep (map ppr deferred_names))]) `thenRn_`
- returnRn (map get_abstract_decl deferred_names)
--}
\end{code}
-@getWiredInDecl@ maps a wired-in @Name@ to what it makes available.
-It behaves exactly as if the wired in decl were actually in an interface file.
-Specifically,
-\begin{itemize}
-\item if the wired-in name is a data type constructor or a data constructor,
- it brings in the type constructor and all the data constructors; and
- marks as ``occurrences'' any free vars of the data con.
-
-\item similarly for synonum type constructor
-
-\item if the wired-in name is another wired-in Id, it marks as ``occurrences''
- the free vars of the Id's type.
-
-\item it loads the interface file for the wired-in thing for the
- sole purpose of making sure that its instance declarations are available
-\end{itemize}
-All this is necessary so that we know all types that are ``in play'', so
-that we know just what instances to bring into scope.
-
%********************************************************
%* *
projects / ghc-hetmet.git / blobdiff