%
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
-%
-\section[RnIfaces]{Cacheing and Renaming of Interfaces}
+section
+\%[RnIfaces]{Cacheing and Renaming of Interfaces}
\begin{code}
-module RnIfaces (
- getInterfaceExports,
- getImportedInstDecls, getImportedRules,
- lookupFixity, loadHomeInterface,
- importDecl, recordSlurp,
- getImportVersions, getSlurped,
-
- checkUpToDate,
-
- getDeclBinders, getDeclSysBinders,
- removeContext -- removeContext probably belongs somewhere else
- ) where
+module RnIfaces
+ ( slurpImpDecls, importSupportingDecls,
+ RecompileRequired, outOfDate, upToDate, checkVersions
+ )
+where
#include "HsVersions.h"
-import CmdLineOpts ( opt_NoPruneDecls, opt_IgnoreIfacePragmas )
-import HsSyn ( HsDecl(..), TyClDecl(..), InstDecl(..), IfaceSig(..),
- HsType(..), ConDecl(..), IE(..), ConDetails(..), Sig(..),
- ForeignDecl(..), ForKind(..), isDynamicExtName,
- FixitySig(..), RuleDecl(..),
- isClassOpSig, Deprecation(..)
+import CmdLineOpts ( opt_IgnoreIfacePragmas, opt_NoPruneDecls )
+import HscTypes
+import HsSyn ( HsDecl(..), Sig(..), TyClDecl(..), ConDecl(..), HsConDetails(..),
+ InstDecl(..), HsType(..), hsTyVarNames, getBangType
)
-import BasicTypes ( Version, NewOrData(..), defaultFixity )
-import RdrHsSyn ( RdrNameHsDecl, RdrNameInstDecl, RdrNameTyClDecl, RdrNameRuleDecl,
- extractHsTyRdrNames, RdrNameDeprecation
- )
-import RnEnv ( mkImportedGlobalName, newImportedBinder, mkImportedGlobalFromRdrName,
- lookupOccRn, lookupImplicitOccRn,
- pprAvail,
- availName, availNames, addAvailToNameSet,
- FreeVars, emptyFVs
- )
-import RnMonad
-import RnHsSyn ( RenamedHsDecl, RenamedDeprecation )
-import ParseIface ( parseIface, IfaceStuff(..) )
-
-import FiniteMap ( FiniteMap, sizeFM, emptyFM, delFromFM, listToFM,
- lookupFM, addToFM, addToFM_C, addListToFM,
- fmToList, elemFM, foldFM
+import RdrHsSyn ( RdrNameTyClDecl, RdrNameInstDecl, RdrNameRuleDecl )
+import RnHsSyn ( RenamedHsDecl, RenamedTyClDecl,
+ extractHsTyNames, extractHsCtxtTyNames,
+ tyClDeclFVs, ruleDeclFVs, impDeclFVs
)
-import Name ( Name {-instance NamedThing-},
- nameModule, isLocallyDefined,
- isWiredInName, nameUnique, NamedThing(..)
- )
-import Module ( Module, moduleString, pprModule,
- mkVanillaModule, pprModuleName,
- moduleUserString, moduleName, isLibModule,
- ModuleName, WhereFrom(..),
- )
-import RdrName ( RdrName, rdrNameOcc )
+import RnHiFiles ( loadInterface, loadHomeInterface, loadOrphanModules )
+import RnNames ( mkModDeps )
+import RnSource ( rnTyClDecl, rnInstDecl, rnIfaceRuleDecl )
+import TcEnv ( getInGlobalScope, tcLookupGlobal_maybe )
+import TcRnMonad
+import Id ( idType, idName, globalIdDetails )
+import IdInfo ( GlobalIdDetails(..) )
+import TcType ( tyClsNamesOfType, classNamesOfTheta )
+import FieldLabel ( fieldLabelTyCon )
+import DataCon ( dataConTyCon, dataConWrapId )
+import TyCon ( visibleDataCons, isSynTyCon, getSynTyConDefn, tyConClass_maybe, tyConName )
+import Class ( className, classSCTheta )
+import Name ( Name {-instance NamedThing-}, isWiredInName, nameIsLocalOrFrom,
+ nameModule, NamedThing(..) )
+import NameEnv ( delFromNameEnv, lookupNameEnv )
import NameSet
-import Var ( Id )
-import SrcLoc ( mkSrcLoc, SrcLoc )
-import PrelMods ( pREL_GHC )
-import PrelInfo ( cCallishTyKeys )
-import Bag
-import Maybes ( MaybeErr(..), maybeToBool, orElse )
-import ListSetOps ( unionLists )
-import Outputable
-import Unique ( Unique )
-import StringBuffer ( StringBuffer, hGetStringBuffer )
-import FastString ( mkFastString )
-import ErrUtils ( Message )
-import Lex
+import Module ( Module, isHomeModule )
+import PrelNames ( hasKey, fractionalClassKey, numClassKey,
+ integerTyConName, doubleTyConName )
import Outputable
-
-import IO ( isDoesNotExistError )
-import List ( nub )
+import Bag
+import Maybe( fromJust )
\end{code}
%*********************************************************
-%* *
-\subsection{Loading a new interface file}
-%* *
+%* *
+\subsection{Slurping declarations}
+%* *
%*********************************************************
\begin{code}
-loadHomeInterface :: SDoc -> Name -> RnM d Ifaces
-loadHomeInterface doc_str name
- = loadInterface doc_str (moduleName (nameModule name)) ImportBySystem `thenRn` \ (_, ifaces) ->
- returnRn ifaces
-
-loadOrphanModules :: [ModuleName] -> RnM d ()
-loadOrphanModules mods
- | null mods = returnRn ()
- | otherwise = traceRn (text "Loading orphan modules:" <+> fsep (map pprModuleName mods)) `thenRn_`
- mapRn_ load mods `thenRn_`
- returnRn ()
- where
- load mod = loadInterface (pprModuleName mod <+> ptext SLIT("is a orphan-instance module")) mod ImportBySystem
-
-loadInterface :: SDoc -> ModuleName -> WhereFrom -> RnM d (Module, Ifaces)
-loadInterface doc_str mod_name from
- = getIfacesRn `thenRn` \ ifaces ->
- let
- mod_map = iImpModInfo ifaces
- mod_info = lookupFM mod_map mod_name
- below_me = case mod_info of
- Nothing -> False
- Just (_, _, is_boot, _) -> not is_boot
- in
-
- -- Issue a warning for a redundant {- SOURCE -} import
- -- It's redundant if the moduld is in the iImpModInfo at all,
- -- because we arrange to read all the ordinary imports before
- -- any of the {- SOURCE -} imports
- warnCheckRn (not (below_me && case from of {ImportByUserSource -> True; other -> False}))
- (warnRedundantSourceImport mod_name) `thenRn_`
-
- -- CHECK WHETHER WE HAVE IT ALREADY
- case mod_info of {
- Just (_, _, _, Just (load_mod, _))
- -> -- We're read it already so don't re-read it
- returnRn (load_mod, ifaces) ;
-
- mod_map_result ->
-
- -- READ THE MODULE IN
- findAndReadIface doc_str mod_name from below_me
- `thenRn` \ (hi_boot_read, read_result) ->
- case read_result of {
- Nothing -> -- Not found, so add an empty export env to the Ifaces map
- -- so that we don't look again
- let
- mod = mkVanillaModule mod_name
- new_mod_map = addToFM mod_map mod_name (0, False, False, Just (mod, []))
- new_ifaces = ifaces { iImpModInfo = new_mod_map }
- in
- setIfacesRn new_ifaces `thenRn_`
- failWithRn (mod, new_ifaces) (noIfaceErr mod hi_boot_read) ;
-
- -- Found and parsed!
- Just (mod, iface) ->
-
- -- LOAD IT INTO Ifaces
-
- -- NB: *first* we do loadDecl, so that the provenance of all the locally-defined
- --- names is done correctly (notably, whether this is an .hi file or .hi-boot file).
- -- If we do loadExport first the wrong info gets into the cache (unless we
- -- explicitly tag each export which seems a bit of a bore)
-
- getModuleRn `thenRn` \ this_mod_nm ->
- let
- rd_decls = pi_decls iface
- in
- foldlRn (loadDecl mod) (iDecls ifaces) rd_decls `thenRn` \ new_decls ->
- foldlRn (loadInstDecl mod) (iInsts ifaces) (pi_insts iface) `thenRn` \ new_insts ->
- (if opt_IgnoreIfacePragmas
- then returnRn emptyBag
- else foldlRn (loadRule mod) (iRules ifaces) (pi_rules iface)) `thenRn` \ new_rules ->
- (if opt_IgnoreIfacePragmas
- then returnRn emptyNameEnv
- else foldlRn (loadDeprec mod) (iDeprecs ifaces) (pi_deprecs iface)) `thenRn` \ new_deprecs ->
- foldlRn (loadFixDecl mod_name) (iFixes ifaces) rd_decls `thenRn` \ new_fixities ->
- mapRn (loadExport this_mod_nm) (pi_exports iface) `thenRn` \ avails_s ->
+-------------------------------------------------------
+slurpImpDecls :: FreeVars -> TcRn m [RenamedHsDecl]
+slurpImpDecls source_fvs
+ = traceRn (text "slurpImp" <+> fsep (map ppr (nameSetToList source_fvs))) `thenM_`
+
+ -- Slurp in things which might be 'gates' for instance
+ -- declarations, plus the instance declarations themselves
+ slurpSourceRefs source_fvs `thenM` \ (gate_decls, bndrs) ->
+
+ -- Then get everything else
let
- -- For an explicit user import, add to mod_map info about
- -- the things the imported module depends on, extracted
- -- from its usage info.
- mod_map1 = case from of
- ImportByUser -> addModDeps mod mod_map (pi_usages iface)
- other -> mod_map
-
- -- Now add info about this module
- mod_map2 = addToFM mod_map1 mod_name mod_details
- mod_details = (pi_mod iface, pi_orphan iface, hi_boot_read, Just (mod, concat avails_s))
-
- new_ifaces = ifaces { iImpModInfo = mod_map2,
- iDecls = new_decls,
- iFixes = new_fixities,
- iInsts = new_insts,
- iRules = new_rules,
- iDeprecs = new_deprecs }
- in
- setIfacesRn new_ifaces `thenRn_`
- returnRn (mod, new_ifaces)
- }}
-
-addModDeps :: Module -> ImportedModuleInfo
- -> [ImportVersion a] -> ImportedModuleInfo
-addModDeps mod mod_deps new_deps
- = foldr add mod_deps new_deps
+ needed = foldr (plusFV . impDeclFVs) emptyFVs gate_decls
+ in
+ import_supporting_decls (gate_decls, bndrs) needed
+
+
+-------------------------------------------------------
+slurpSourceRefs :: FreeVars -- Variables referenced in source
+ -> TcRn m ([RenamedHsDecl], -- Needed declarations
+ NameSet) -- Names bound by those declarations
+-- Slurp imported declarations needed directly by the source code;
+-- and some of the ones they need. The goal is to find all the 'gates'
+-- for instance declarations.
+
+slurpSourceRefs source_fvs
+ = go_outer [] emptyFVs -- Accumulating decls
+ (nameSetToList source_fvs) -- Things whose defn hasn't been loaded yet
where
- is_lib = isLibModule mod -- Don't record dependencies when importing a library module
- add (imp_mod, version, has_orphans, is_boot, _) deps
- | is_lib && not has_orphans = deps
- | otherwise = addToFM_C combine deps imp_mod (version, has_orphans, is_boot, Nothing)
- -- Record dependencies for modules that are
- -- either are dependent via a non-library module
- -- or contain orphan rules or instance decls
-
- -- Don't ditch a module that's already loaded
- -- If it isn't loaded, and together the is_boot-ness
- combine old@(_, _, _, Just _) new = old
- combine old@(_, _, old_is_boot, Nothing)
- new@(version, has_orphans, new_is_boot, _)
- = (version, has_orphans, old_is_boot && new_is_boot, Nothing)
-
-loadExport :: ModuleName -> ExportItem -> RnM d [AvailInfo]
-loadExport this_mod (mod, entities)
- | mod == this_mod = returnRn []
- -- If the module exports anything defined in this module, just ignore it.
- -- Reason: otherwise it looks as if there are two local definition sites
- -- for the thing, and an error gets reported. Easiest thing is just to
- -- filter them out up front. This situation only arises if a module
- -- imports itself, or another module that imported it. (Necessarily,
- -- this invoves a loop.) Consequence: if you say
- -- module A where
- -- import B( AType )
- -- type AType = ...
- --
- -- module B( AType ) where
- -- import {-# SOURCE #-} A( AType )
+ -- The outer loop repeatedly slurps the decls for the current gates
+ -- 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.
--
- -- then you'll get a 'B does not export AType' message. A bit bogus
- -- but it's a bogus thing to do!
+ -- 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 bndrs [] = returnM (decls, bndrs)
+
+ go_outer decls bndrs refs -- 'refs' are not necessarily slurped yet
+ = traceRn (text "go_outer" <+> ppr refs) `thenM_`
+ foldlM go_inner (decls, bndrs, emptyFVs) refs `thenM` \ (decls1, bndrs1, gates1) ->
+ getImportedInstDecls gates1 `thenM` \ (inst_decls, new_gates) ->
+ rnIfaceDecls rnInstDecl inst_decls `thenM` \ inst_decls' ->
+ go_outer (map InstD inst_decls' ++ decls1)
+ bndrs1
+ (nameSetToList (new_gates `plusFV` plusFVs (map getInstDeclGates inst_decls')))
+ -- NB: we go round again to fetch the decls for any gates of any decls
+ -- we have loaded. For example, if we mention
+ -- print :: Show a => a -> String
+ -- then we must load the decl for Show before stopping, to ensure
+ -- that instances from its home module are available
+
+ go_inner (decls, bndrs, gates) wanted_name
+ = importDecl bndrs wanted_name `thenM` \ import_result ->
+ case import_result of
+ AlreadySlurped -> returnM (decls, bndrs, gates)
+
+ InTypeEnv ty_thing
+ -> returnM (decls,
+ bndrs `addOneFV` wanted_name, -- Avoid repeated calls to getWiredInGates
+ gates `plusFV` getWiredInGates ty_thing)
+
+ HereItIs decl new_bndrs
+ -> rnIfaceDecl rnTyClDecl decl `thenM` \ new_decl ->
+ returnM (TyClD new_decl : decls,
+ bndrs `plusFV` new_bndrs,
+ gates `plusFV` getGates source_fvs new_decl)
+\end{code}
- | otherwise
- = mapRn (load_entity mod) entities
+\begin{code}
+-------------------------------------------------------
+-- import_supporting_decls keeps going until the free-var set is empty
+importSupportingDecls needed
+ = import_supporting_decls ([], emptyNameSet) needed
+
+import_supporting_decls
+ :: ([RenamedHsDecl], NameSet) -- Some imported decls, with their binders
+ -> FreeVars -- Remaining un-slurped names
+ -> TcRn m [RenamedHsDecl]
+import_supporting_decls decls needed
+ = slurpIfaceDecls decls needed `thenM` \ (decls1, bndrs1) ->
+ getImportedRules bndrs1 `thenM` \ rule_decls ->
+ case rule_decls of
+ [] -> returnM decls1 -- No new rules, so we are done
+ other -> rnIfaceDecls rnIfaceRuleDecl rule_decls `thenM` \ rule_decls' ->
+ let
+ rule_fvs = plusFVs (map ruleDeclFVs rule_decls')
+ decls2 = decls1 ++ map RuleD rule_decls'
+ in
+ traceRn (text "closeRules" <+> ppr rule_decls' $$
+ fsep (map ppr (nameSetToList rule_fvs))) `thenM_`
+ import_supporting_decls (decls2, bndrs1) rule_fvs
+
+
+-------------------------------------------------------
+-- Augment decls with any decls needed by needed,
+-- and so on transitively
+slurpIfaceDecls :: ([RenamedHsDecl], NameSet) -- Already slurped
+ -> FreeVars -- Still needed
+ -> TcRn m ([RenamedHsDecl], NameSet)
+slurpIfaceDecls (decls, bndrs) needed
+ = slurp decls bndrs (nameSetToList needed)
where
- new_name mod occ = mkImportedGlobalName mod occ
-
- load_entity mod (Avail occ)
- = new_name mod occ `thenRn` \ name ->
- returnRn (Avail name)
- load_entity mod (AvailTC occ occs)
- = new_name mod occ `thenRn` \ name ->
- mapRn (new_name mod) occs `thenRn` \ names ->
- returnRn (AvailTC name names)
-
-
-loadFixDecl :: ModuleName -> FixityEnv
- -> (Version, RdrNameHsDecl)
- -> RnM d FixityEnv
-loadFixDecl mod_name fixity_env (version, FixD sig@(FixitySig rdr_name fixity loc))
- = -- Ignore the version; when the fixity changes the version of
- -- its 'host' entity changes, so we don't need a separate version
- -- number for fixities
- mkImportedGlobalName mod_name (rdrNameOcc rdr_name) `thenRn` \ name ->
- let
- new_fixity_env = addToNameEnv fixity_env name (FixitySig name fixity loc)
- in
- returnRn new_fixity_env
-
- -- Ignore the other sorts of decl
-loadFixDecl mod_name fixity_env other_decl = returnRn fixity_env
-
-loadDecl :: Module
- -> DeclsMap
- -> (Version, RdrNameHsDecl)
- -> RnM d DeclsMap
+ slurp decls bndrs [] = returnM (decls, bndrs)
+ slurp decls bndrs (n:ns)
+ = importDecl bndrs n `thenM` \ import_result ->
+ case import_result of
+ HereItIs decl new_bndrs -- Found a declaration... rename it
+ -> rnIfaceDecl rnTyClDecl decl `thenM` \ new_decl ->
+ slurp (TyClD new_decl : decls)
+ (bndrs `plusFV` new_bndrs)
+ (nameSetToList (tyClDeclFVs new_decl) ++ ns)
+
+
+ other -> -- No declaration... (wired in thing, or deferred,
+ -- or already slurped)
+ slurp decls (bndrs `addOneFV` n) ns
+
+-------------------------------------------------------
+rnIfaceDecls rn decls = mappM (rnIfaceDecl rn) decls
+rnIfaceDecl rn (mod, decl) = initRn (InterfaceMode mod) (rn decl)
+\end{code}
-loadDecl mod decls_map (version, decl)
- = getDeclBinders new_name decl `thenRn` \ maybe_avail ->
- case maybe_avail of {
- Nothing -> returnRn decls_map; -- No bindings
- Just avail ->
- getDeclSysBinders new_name decl `thenRn` \ sys_bndrs ->
- let
- main_name = availName avail
- new_decls_map = foldl add_decl decls_map
- [ (name, (version, avail, name==main_name, (mod, decl')))
- | name <- sys_bndrs ++ availNames avail]
- add_decl decls_map (name, stuff)
- = WARN( name `elemNameEnv` decls_map, ppr name )
- addToNameEnv decls_map name stuff
- in
- returnRn new_decls_map
- }
+\begin{code}
+ -- Tiresomely, we must get the "main" name for the
+ -- thing, because that's what VSlurp contains, and what
+ -- is recorded in the usage information
+get_main_name (AClass cl) = className cl
+get_main_name (ADataCon dc) = tyConName (dataConTyCon dc)
+get_main_name (ATyCon tc)
+ | Just clas <- tyConClass_maybe tc = get_main_name (AClass clas)
+ | otherwise = tyConName tc
+get_main_name (AnId id)
+ = case globalIdDetails id of
+ DataConWorkId dc -> get_main_name (ATyCon (dataConTyCon dc))
+ DataConWrapId dc -> get_main_name (ATyCon (dataConTyCon dc))
+ RecordSelId lbl -> get_main_name (ATyCon (fieldLabelTyCon lbl))
+ GenericOpId tc -> get_main_name (ATyCon tc)
+ ClassOpId cl -> className cl
+ other -> idName id
+
+
+recordUsage :: Name -> TcRn m ()
+-- Record that the Name has been used, for
+-- later generation of usage info in the interface file
+recordUsage name = updUsages (upd_usg name)
+
+upd_usg name usages
+ | isHomeModule mod = addOneToNameSet usages name
+ | otherwise = usages
where
- -- newImportedBinder puts into the cache the binder with the
- -- module information set correctly. When the decl is later renamed,
- -- the binding site will thereby get the correct module.
- new_name rdr_name loc = newImportedBinder mod rdr_name
-
- {-
- If a signature decl is being loaded, and optIgnoreIfacePragmas is on,
- we toss away unfolding information.
-
- Also, if the signature is loaded from a module we're importing from source,
- we do the same. This is to avoid situations when compiling a pair of mutually
- recursive modules, peering at unfolding info in the interface file of the other,
- e.g., you compile A, it looks at B's interface file and may as a result change
- its interface file. Hence, B is recompiled, maybe changing its interface file,
- which will the unfolding info used in A to become invalid. Simple way out is to
- just ignore unfolding info.
-
- [Jan 99: I junked the second test above. If we're importing from an hi-boot
- file there isn't going to *be* any pragma info. Maybe the above comment
- dates from a time where we picked up a .hi file first if it existed?]
- -}
- decl' = case decl of
- SigD (IfaceSig name tp ls loc) | opt_IgnoreIfacePragmas
- -> SigD (IfaceSig name tp [] loc)
- other -> decl
-
-loadInstDecl :: Module
- -> Bag GatedDecl
- -> RdrNameInstDecl
- -> RnM d (Bag GatedDecl)
-loadInstDecl mod insts decl@(InstDecl inst_ty binds uprags dfun_name src_loc)
- =
- -- Find out what type constructors and classes are "gates" for the
- -- instance declaration. If all these "gates" are slurped in then
- -- we should slurp the instance decl too.
- --
- -- We *don't* want to count names in the context part as gates, though.
- -- For example:
- -- instance Foo a => Baz (T a) where ...
- --
- -- Here the gates are Baz and T, but *not* Foo.
- let
- munged_inst_ty = removeContext inst_ty
- free_names = extractHsTyRdrNames munged_inst_ty
- in
- setModuleRn (moduleName mod) $
- mapRn mkImportedGlobalFromRdrName free_names `thenRn` \ gate_names ->
- returnRn ((mkNameSet gate_names, (mod, InstD decl)) `consBag` insts)
-
-
--- In interface files, the instance decls now look like
--- forall a. Foo a -> Baz (T a)
--- so we have to strip off function argument types as well
--- as the bit before the '=>' (which is always empty in interface files)
-removeContext (HsForAllTy tvs cxt ty) = HsForAllTy tvs [] (removeFuns ty)
-removeContext ty = removeFuns ty
-
-removeFuns (MonoFunTy _ ty) = removeFuns ty
-removeFuns ty = ty
-
-
-loadRule :: Module -> Bag GatedDecl
- -> RdrNameRuleDecl -> RnM d (Bag GatedDecl)
--- "Gate" the rule simply by whether the rule variable is
--- needed. We can refine this later.
-loadRule mod rules decl@(IfaceRuleDecl var body src_loc)
- = setModuleRn (moduleName mod) $
- mkImportedGlobalFromRdrName var `thenRn` \ var_name ->
- returnRn ((unitNameSet var_name, (mod, RuleD decl)) `consBag` rules)
-
--- SUP: TEMPORARY HACK, ignoring module deprecations for now
-loadDeprec :: Module -> DeprecationEnv -> RdrNameDeprecation -> RnM d DeprecationEnv
-loadDeprec mod deprec_env (Deprecation (IEModuleContents _) txt)
- = traceRn (text "module deprecation not yet implemented:" <+> ppr mod <> colon <+> ppr txt) `thenRn_`
- returnRn deprec_env
-loadDeprec mod deprec_env (Deprecation ie txt)
- = setModuleRn (moduleName mod) $
- mapRn mkImportedGlobalFromRdrName (namesFromIE ie) `thenRn` \ names ->
- traceRn (text "loaded deprecation(s) for" <+> hcat (punctuate comma (map ppr names)) <> colon <+> ppr txt) `thenRn_`
- returnRn (extendNameEnv deprec_env (zip names (repeat txt)))
-
-namesFromIE :: IE a -> [a]
-namesFromIE (IEVar n ) = [n]
-namesFromIE (IEThingAbs n ) = [n]
-namesFromIE (IEThingAll n ) = [n]
-namesFromIE (IEThingWith n ns) = n:ns
-namesFromIE (IEModuleContents _ ) = []
+ mod = nameModule name
\end{code}
-%********************************************************
+%*********************************************************
%* *
-\subsection{Loading usage information}
+\subsection{Getting in a declaration}
%* *
-%********************************************************
+%*********************************************************
\begin{code}
-checkUpToDate :: ModuleName -> RnMG Bool -- True <=> no need to recompile
-checkUpToDate mod_name
- = getIfacesRn `thenRn` \ ifaces ->
- findAndReadIface doc_str mod_name
- ImportByUser
- (error "checkUpToDate") `thenRn` \ (_, read_result) ->
-
- -- CHECK WHETHER WE HAVE IT ALREADY
- case read_result of
- Nothing -> -- Old interface file not found, so we'd better bail out
- traceRn (sep [ptext SLIT("Didnt find old iface"),
- pprModuleName mod_name]) `thenRn_`
- returnRn False
-
- Just (_, iface)
- -> -- Found it, so now check it
- checkModUsage (pi_usages iface)
- where
- -- Only look in current directory, with suffix .hi
- doc_str = sep [ptext SLIT("need usage info from"), pprModuleName mod_name]
-
-checkModUsage [] = returnRn True -- Yes! Everything is up to date!
-
-checkModUsage ((mod_name, old_mod_vers, _, _, Specifically []) : rest)
- -- If CurrentModule.hi contains
- -- import Foo :: ;
- -- then that simply records that Foo lies below CurrentModule in the
- -- hierarchy, but CurrentModule doesn't depend in any way on Foo.
- -- In this case we don't even want to open Foo's interface.
- = traceRn (ptext SLIT("Nothing used from:") <+> ppr mod_name) `thenRn_`
- checkModUsage rest -- This one's ok, so check the rest
-
-checkModUsage ((mod_name, old_mod_vers, _, _, whats_imported) : rest)
- = loadInterface doc_str mod_name ImportBySystem `thenRn` \ (mod, ifaces) ->
- let
- maybe_mod_vers = case lookupFM (iImpModInfo ifaces) mod_name of
- Just (version, _, _, Just (_, _)) -> Just version
- other -> Nothing
- in
- case maybe_mod_vers of {
- Nothing -> -- If we can't find a version number for the old module then
- -- bail out saying things aren't up to date
- traceRn (sep [ptext SLIT("Can't find version number for module"),
- pprModuleName mod_name])
- `thenRn_` returnRn False ;
-
- Just new_mod_vers ->
-
- -- If the module version hasn't changed, just move on
- if new_mod_vers == old_mod_vers then
- traceRn (sep [ptext SLIT("Module version unchanged:"), pprModuleName mod_name])
- `thenRn_` checkModUsage rest
+importDecl :: NameSet -> Name -> TcRn m ImportDeclResult
+
+data ImportDeclResult
+ = AlreadySlurped
+ | InTypeEnv TyThing
+ | HereItIs (Module, RdrNameTyClDecl) NameSet
+ -- The NameSet is the bunch of names bound by this decl
+
+importDecl already_slurped name
+ = -- STEP 0: Check if it's from this module
+ -- Doing this catches a common case quickly
+ getModule `thenM` \ this_mod ->
+ if nameIsLocalOrFrom this_mod name then
+ -- Variables defined on the GHCi command line (e.g. let x = 3)
+ -- are Internal names (which don't have a Module)
+ returnM AlreadySlurped
else
- traceRn (sep [ptext SLIT("Module version has changed:"), pprModuleName mod_name])
- `thenRn_`
- -- Module version changed, so check entities inside
-
- -- If the usage info wants to say "I imported everything from this module"
- -- it does so by making whats_imported equal to Everything
- -- In that case, we must recompile
- case whats_imported of {
- Everything -> traceRn (ptext SLIT("...and I needed the whole module")) `thenRn_`
- returnRn False; -- Bale out
-
- Specifically old_local_vers ->
-
- -- Non-empty usage list, so check item by item
- checkEntityUsage mod_name (iDecls ifaces) old_local_vers `thenRn` \ up_to_date ->
- if up_to_date then
- traceRn (ptext SLIT("...but the bits I use haven't.")) `thenRn_`
- checkModUsage rest -- This one's ok, so check the rest
+
+ -- STEP 1: Check if we've slurped it in while compiling this module
+ if name `elemNameSet` already_slurped then
+ returnM AlreadySlurped
else
- returnRn False -- This one failed, so just bail out now
- }}
- where
- doc_str = sep [ptext SLIT("need version info for"), pprModuleName mod_name]
+ -- STEP 2: Check if it's already in the type environment
+ tcLookupGlobal_maybe name `thenM` \ maybe_thing ->
+ case maybe_thing of {
-checkEntityUsage mod decls []
- = returnRn True -- Yes! All up to date!
+ Just ty_thing
+ | isWiredInName 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 `thenM_`
+ returnM (InTypeEnv ty_thing)
-checkEntityUsage mod decls ((occ_name,old_vers) : rest)
- = mkImportedGlobalName mod occ_name `thenRn` \ name ->
- case lookupNameEnv decls name of
+ | otherwise
+ -> -- We have slurp something that's already in the type environment,
+ -- that was not slurped in an earlier compilation.
+ -- Must still record it in the Usages info, because that's used to
+ -- generate usage information
+
+ traceRn (text "not wired in" <+> ppr name) `thenM_`
+ recordUsage (get_main_name ty_thing) `thenM_`
+ returnM (InTypeEnv ty_thing) ;
+
+ Nothing ->
+
+ -- STEP 4: OK, we have to slurp it in from an interface file
+ -- First load the interface file
+ traceRn nd_doc `thenM_`
+ loadHomeInterface nd_doc name `thenM_`
+
+ -- STEP 4: Get the declaration out
+ getEps `thenM` \ eps ->
+ let
+ (decls_map, n_slurped) = eps_decls eps
+ in
+ case lookupNameEnv decls_map name of
+ Just (avail,_,decl) -> setEps eps' `thenM_`
+ recordUsage (availName avail) `thenM_`
+ returnM (HereItIs decl (mkFVs avail_names))
+ where
+ avail_names = availNames avail
+ new_decls_map = foldl delFromNameEnv decls_map avail_names
+ eps' = eps { eps_decls = (new_decls_map, n_slurped+1) }
+
+ Nothing -> addErr (getDeclErr name) `thenM_`
+ returnM AlreadySlurped
+ }
+ where
+ wi_doc = ptext SLIT("need home module for wired in thing") <+> ppr name
+ nd_doc = ptext SLIT("need decl for") <+> ppr name
- Nothing -> -- We used it before, but it ain't there now
- traceRn (sep [ptext SLIT("No longer exported:"), ppr name])
- `thenRn_` returnRn False
-
- Just (new_vers,_,_,_) -- It's there, but is it up to date?
- | new_vers == old_vers
- -- Up to date, so check the rest
- -> checkEntityUsage mod decls rest
-
- | otherwise
- -- Out of date, so bale out
- -> traceRn (sep [ptext SLIT("Out of date:"), ppr name]) `thenRn_`
- returnRn False
\end{code}
%*********************************************************
-%* *
-\subsection{Getting in a declaration}
-%* *
+%* *
+\subsection{Extracting the `gates'}
+%* *
%*********************************************************
-\begin{code}
-importDecl :: Name -> RnMG (Maybe (Module, RdrNameHsDecl))
- -- Returns Nothing for
- -- (a) wired in name
- -- (b) local decl
- -- (c) already slurped
-
-importDecl name
- | isWiredInName name
- = returnRn Nothing
- | otherwise
- = getSlurped `thenRn` \ already_slurped ->
- if name `elemNameSet` already_slurped then
- returnRn Nothing -- Already dealt with
- else
- if isLocallyDefined name then -- Don't bring in decls from
- -- the renamed module's own interface file
- addWarnRn (importDeclWarn name) `thenRn_`
- returnRn Nothing
- else
- getNonWiredInDecl name
-\end{code}
+The gating story
+~~~~~~~~~~~~~~~~~
+We want to avoid sucking in too many instance declarations.
+An instance decl is only useful if the types and classes mentioned in
+its 'head' are all available in the program being compiled. E.g.
+
+ instance (..) => C (T1 a) (T2 b) where ...
+
+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.
+
+More precisely, the gates of a module are the types and classes
+that are mentioned in:
+
+ a) the source code [Note: in fact these don't seem
+ to be treated as gates, perhaps
+ because no imported instance decl
+ can mention them; mutter mutter
+ recursive modules.]
+ 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 the gates of a previously-loaded module
-\begin{code}
-getNonWiredInDecl :: Name -> RnMG (Maybe (Module, RdrNameHsDecl))
-getNonWiredInDecl needed_name
- = traceRn doc_str `thenRn_`
- loadHomeInterface doc_str needed_name `thenRn` \ ifaces ->
- case lookupNameEnv (iDecls ifaces) needed_name of
-
- Just (version,avail,_,decl)
- -> recordSlurp (Just version) avail `thenRn_`
- returnRn (Just decl)
-
- Nothing -- Can happen legitimately for "Optional" occurrences
- -> addErrRn (getDeclErr needed_name) `thenRn_`
- returnRn Nothing
- where
- doc_str = ptext SLIT("need decl for") <+> ppr needed_name
-\end{code}
+The latter constraint is because there might have been an instance
+decl slurped in during an earlier compilation, like this:
-@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.
+ instance Foo a => Baz (Maybe a) where ...
-\item similarly for synonum type constructor
+In the module being compiled we might need (Baz (Maybe T)), where T is
+defined in this module, and hence we need the instance for (Foo T).
+So @Foo@ becomes a gate. But there's no way to 'see' that. More
+generally, types might be involved as well:
-\item if the wired-in name is another wired-in Id, it marks as ``occurrences''
- the free vars of the Id's type.
+ instance Foo2 S a => Baz2 a where ...
-\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.
-
+Now we must treat S as a gate too, as well as Foo2. So the solution
+we adopt is:
+ we simply treat the gates of all previously-loaded
+ modules as gates of this one
-
-%*********************************************************
-%* *
-\subsection{Getting what a module exports}
-%* *
-%*********************************************************
+So the gates are remembered across invocations of the renamer in the
+PersistentRenamerState. This gloss mainly affects ghc --make and ghc
+--interactive.
+
+(We used to use the persistent type environment for this purpose,
+but it has too much. For a start, it contains all tuple types,
+because they are in the wired-in type env!)
+
+
+Consructors and class operations
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+When we import a declaration like
+
+ data T = T1 Wibble | T2 Wobble
-@getInterfaceExports@ is called only for directly-imported modules.
+we don't want to treat @Wibble@ and @Wobble@ as gates {\em unless}
+@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.
+
+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}
-getInterfaceExports :: ModuleName -> WhereFrom -> RnMG (Module, Avails)
-getInterfaceExports mod_name from
- = loadInterface doc_str mod_name from `thenRn` \ (mod, ifaces) ->
- case lookupFM (iImpModInfo ifaces) mod_name of
- Nothing -> -- Not there; it must be that the interface file wasn't found;
- -- the error will have been reported already.
- -- (Actually loadInterface should put the empty export env in there
- -- anyway, but this does no harm.)
- returnRn (mod, [])
-
- Just (_, _, _, Just (mod, avails)) -> returnRn (mod, avails)
+getGates :: FreeVars -- Things mentioned in the source program
+ -- Used for the cunning "constructors and
+ -- class ops" story described 10 lines above.
+ -> RenamedTyClDecl
+ -> FreeVars
+
+getGates source_fvs decl
+ = get_gates (\n -> n `elemNameSet` source_fvs) decl
+
+get_gates is_used (ForeignType {tcdName = tycon}) = unitNameSet tycon
+get_gates is_used (IfaceSig {tcdType = ty}) = extractHsTyNames ty
+
+get_gates is_used (ClassDecl { tcdCtxt = ctxt, tcdName = cls, tcdTyVars = tvs, tcdSigs = sigs})
+ = (super_cls_and_sigs `addOneToNameSet` cls) `unionNameSets`
+ implicitClassGates cls
where
- doc_str = sep [pprModuleName mod_name, ptext SLIT("is directly imported")]
+ super_cls_and_sigs = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) sigs)
+ (hsTyVarNames tvs)
+ get (ClassOpSig n _ ty _)
+ | is_used n = extractHsTyNames ty
+ | otherwise = emptyFVs
+
+get_gates is_used (TySynonym {tcdTyVars = tvs, tcdSynRhs = ty})
+ = delListFromNameSet (extractHsTyNames ty) (hsTyVarNames tvs)
+ -- A type synonym type constructor isn't a "gate" for instance decls
+
+get_gates is_used (TyData {tcdCtxt = ctxt, tcdName = tycon, tcdTyVars = tvs, tcdCons = cons})
+ = delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt)
+ (visibleDataCons cons))
+ (hsTyVarNames tvs)
+ `addOneToNameSet` tycon
+ where
+ get (ConDecl n tvs ctxt details _)
+ | is_used n
+ -- If the constructor is method, get fvs from all its fields
+ = delListFromNameSet (get_details details `plusFV`
+ extractHsCtxtTyNames ctxt)
+ (hsTyVarNames tvs)
+ get (ConDecl n tvs ctxt (RecCon fields) _)
+ -- Even if the constructor isn't mentioned, the fields
+ -- might be, as selectors. They can't mention existentially
+ -- bound tyvars (typechecker checks for that) so no need for
+ -- the deleteListFromNameSet part
+ = foldr (plusFV . get_field) emptyFVs fields
+
+ get other_con = emptyFVs
+
+ get_details (PrefixCon tys) = plusFVs (map get_bang tys)
+ get_details (InfixCon t1 t2) = get_bang t1 `plusFV` get_bang t2
+ get_details (RecCon fields) = plusFVs [get_bang t | (_, t) <- fields]
+
+ get_field (f,t) | is_used f = get_bang t
+ | otherwise = emptyFVs
+
+ get_bang bty = extractHsTyNames (getBangType bty)
+
+implicitClassGates :: Name -> FreeVars
+implicitClassGates cls
+ -- If we load class Num, add Integer to the free gates
+ -- This takes account of the fact that Integer might be needed for
+ -- defaulting, but we don't want to load Integer (and all its baggage)
+ -- if there's no numeric stuff needed.
+ -- Similarly for class Fractional and Double
+ --
+ -- NB: adding T to the gates will force T to be loaded
+ --
+ -- NB: If we load (say) Floating, we'll end up loading Fractional too,
+ -- since Fractional is a superclass of Floating
+ | cls `hasKey` numClassKey = unitFV integerTyConName
+ | cls `hasKey` fractionalClassKey = unitFV doubleTyConName
+ | otherwise = emptyFVs
\end{code}
+@getWiredInGates@ is just like @getGates@, but it sees a previously-loaded
+thing rather than a declaration.
-%*********************************************************
-%* *
-\subsection{Instance declarations are handled specially}
-%* *
-%*********************************************************
+\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 (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 (AClass cl)
+ = unitFV (getName cl) `plusFV` mkFVs super_classes
+ where
+ super_classes = classNamesOfTheta (classSCTheta cl)
+
+getWiredInGates (AnId the_id) = tyClsNamesOfType (idType the_id)
+getWiredInGates (ADataCon dc) = tyClsNamesOfType (idType (dataConWrapId dc))
+getWiredInGates (ATyCon tc)
+ | isSynTyCon tc = tyClsNamesOfType ty
+ | otherwise = unitFV (getName tc)
+ where
+ (_,ty) = getSynTyConDefn tc
+
+getInstDeclGates (InstDecl inst_ty _ _ _ _) = extractHsTyNames inst_ty
+\end{code}
\begin{code}
-getImportedInstDecls :: NameSet -> RnMG [(Module,RdrNameHsDecl)]
+getImportedInstDecls :: NameSet -> TcRn m ([(Module,RdrNameInstDecl)], NameSet)
+ -- Returns the gates that are new since last time
getImportedInstDecls gates
= -- First, load any orphan-instance modules that aren't aready loaded
-- Orphan-instance modules are recorded in the module dependecnies
- getIfacesRn `thenRn` \ ifaces ->
+ getImports `thenM` \ imports ->
+ getEps `thenM` \ eps ->
let
- orphan_mods =
- [mod | (mod, (_, True, _, Nothing)) <- fmToList (iImpModInfo ifaces)]
+ old_gates = eps_inst_gates eps
+ new_gates = gates `minusNameSet` old_gates
+ all_gates = new_gates `unionNameSets` old_gates
+ orphan_mods = imp_orphs imports
in
- loadOrphanModules orphan_mods `thenRn_`
+ loadOrphanModules orphan_mods `thenM_`
-- Now we're ready to grab the instance declarations
-- Find the un-gated ones and return them,
- -- removing them from the bag kept in Ifaces
- getIfacesRn `thenRn` \ ifaces ->
+ -- removing them from the bag kept in EPS
+ -- Don't foget to get the EPS a second time...
+ -- loadOrphanModules may have side-effected it!
+ getEps `thenM` \ eps ->
let
- (decls, new_insts) = selectGated gates (iInsts ifaces)
+ available n = n `elemNameSet` all_gates
+ (decls, new_insts) = selectGated available (eps_insts eps)
in
- setIfacesRn (ifaces { iInsts = new_insts }) `thenRn_`
+ setEps (eps { eps_insts = new_insts,
+ eps_inst_gates = all_gates }) `thenM_`
traceRn (sep [text "getImportedInstDecls:",
- nest 4 (fsep (map ppr gate_list)),
+ nest 4 (fsep (map ppr (nameSetToList gates))),
+ nest 4 (fsep (map ppr (nameSetToList all_gates))),
+ nest 4 (fsep (map ppr (nameSetToList new_gates))),
text "Slurped" <+> int (length decls) <+> text "instance declarations",
- nest 4 (vcat (map ppr_brief_inst_decl decls))]) `thenRn_`
- returnRn decls
- where
- gate_list = nameSetToList gates
+ nest 4 (vcat (map ppr_brief_inst_decl decls))]) `thenM_`
+ returnM (decls, new_gates)
- load_home gate | isLocallyDefined gate
- = returnRn ()
- | otherwise
- = loadHomeInterface (ppr gate <+> text "is an instance gate") gate `thenRn_`
- returnRn ()
-
-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
- | opt_IgnoreIfacePragmas = returnRn []
+getImportedRules :: NameSet -- Slurped already
+ -> TcRn m [(Module,RdrNameRuleDecl)]
+getImportedRules slurped
+ | opt_IgnoreIfacePragmas = returnM []
| otherwise
- = getIfacesRn `thenRn` \ ifaces ->
- let
- gates = iSlurp ifaces -- Anything at all that's been slurped
- (decls, new_rules) = selectGated gates (iRules ifaces)
+ = getEps `thenM` \ eps ->
+ getInGlobalScope `thenM` \ in_type_env ->
+ let -- Slurp rules for anything that is slurped,
+ -- either now, or previously
+ available n = n `elemNameSet` slurped || in_type_env n
+ (decls, new_rules) = selectGated available (eps_rules eps)
in
- setIfacesRn (ifaces { iRules = new_rules }) `thenRn_`
+ if null decls then
+ returnM []
+ else
+ setEps (eps { eps_rules = new_rules }) `thenM_`
traceRn (sep [text "getImportedRules:",
- text "Slurped" <+> int (length decls) <+> text "rules"]) `thenRn_`
- returnRn decls
+ text "Slurped" <+> int (length decls) <+> text "rules"]) `thenM_`
+ returnM decls
-selectGated gates decl_bag
- -- Select only those decls whose gates are *all* in 'gates'
+selectGated :: (Name->Bool) -> GatedDecls d
+ -> ([(Module,d)], GatedDecls d)
+selectGated available (decl_bag, n_slurped)
+ -- Select only those decls whose gates are *all* available
#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
- where
- select (reqd, decl) (yes, no)
- | isEmptyNameSet (reqd `minusNameSet` gates) = (decl:yes, no)
- | otherwise = (yes, (reqd,decl) `consBag` no)
-
-lookupFixity :: Name -> RnMS Fixity
-lookupFixity name
- | isLocallyDefined name
- = getFixityEnv `thenRn` \ local_fix_env ->
- case lookupNameEnv local_fix_env name of
- Just (FixitySig _ fix _) -> returnRn fix
- Nothing -> returnRn defaultFixity
-
- | otherwise -- Imported
- -- For imported names, we have to get their fixities by doing a loadHomeInterface,
- -- and consulting the Ifaces that comes back from that, because the interface
- -- file for the Name might not have been loaded yet. Why not? Suppose you import module A,
- -- which exports a function 'f', which is defined in module B. Then B isn't loaded
- -- right away (after all, it's possible that nothing from B will be used).
- -- When we come across a use of 'f', we need to know its fixity, and it's then,
- -- and only then, that we load B.hi. That is what's happening here.
- = loadHomeInterface doc name `thenRn` \ ifaces ->
- case lookupNameEnv (iFixes ifaces) name of
- Just (FixitySig _ fix _) -> returnRn fix
- Nothing -> returnRn defaultFixity
+ = case foldrBag select ([], emptyBag) decl_bag of
+ (decls, new_bag) -> (decls, (new_bag, n_slurped + length decls))
where
- doc = ptext SLIT("Checking fixity for") <+> ppr name
+ select (gate_fn, decl) (yes, no)
+ | gate_fn available = (decl:yes, no)
+ | otherwise = (yes, (gate_fn,decl) `consBag` no)
\end{code}
-%*********************************************************
+%********************************************************
%* *
-\subsection{Keeping track of what we've slurped, and version numbers}
+\subsection{Checking usage information}
%* *
-%*********************************************************
+%********************************************************
-getImportVersions figures out what the ``usage information'' for this
-moudule is; that is, what it must record in its interface file as the
-things it uses. It records:
-
-\begin{itemize}
-\item (a) anything reachable from its body code
-\item (b) any module exported with a @module Foo@
-\item (c) anything reachable from an exported item
-\end{itemize}
-
-Why (b)? Because if @Foo@ changes then this module's export list
-will change, so we must recompile this module at least as far as
-making a new interface file --- but in practice that means complete
-recompilation.
-
-Why (c)? Consider this:
-\begin{verbatim}
- module A( f, g ) where | module B( f ) where
- import B( f ) | f = h 3
- g = ... | h = ...
-\end{verbatim}
-
-Here, @B.f@ isn't used in A. Should we nevertheless record @B.f@ in
-@A@'s usages? Our idea is that we aren't going to touch A.hi if it is
-*identical* to what it was before. If anything about @B.f@ changes
-than anyone who imports @A@ should be recompiled in case they use
-@B.f@ (they'll get an early exit if they don't). So, if anything
-about @B.f@ changes we'd better make sure that something in A.hi
-changes, and the convenient way to do that is to record the version
-number @B.f@ in A.hi in the usage list. If B.f changes that'll force a
-complete recompiation of A, which is overkill but it's the only way to
-write a new, slightly different, A.hi.
-
-But the example is tricker. Even if @B.f@ doesn't change at all,
-@B.h@ may do so, and this change may not be reflected in @f@'s version
-number. But with -O, a module that imports A must be recompiled if
-@B.h@ changes! So A must record a dependency on @B.h@. So we treat
-the occurrence of @B.f@ in the export list *just as if* it were in the
-code of A, and thereby haul in all the stuff reachable from it.
-
-[NB: If B was compiled with -O, but A isn't, we should really *still*
-haul in all the unfoldings for B, in case the module that imports A *is*
-compiled with -O. I think this is the case.]
-
-Even if B is used at all we get a usage line for B
- import B <n> :: ... ;
-in A.hi, to record the fact that A does import B. This is used to decide
-to look to look for B.hi rather than B.hi-boot when compiling a module that
-imports A. This line says that A imports B, but uses nothing in it.
-So we'll get an early bale-out when compiling A if B's version changes.
+@recompileRequired@ is called from the HscMain. It checks whether
+a recompilation is required. It needs access to the persistent state,
+finder, etc, because it may have to load lots of interface files to
+check their versions.
\begin{code}
-getImportVersions :: ModuleName -- Name of this module
- -> ExportEnv -- Info about exports
- -> RnMG (VersionInfo Name) -- Version info for these names
-
-getImportVersions this_mod (ExportEnv _ _ export_all_mods)
- = getIfacesRn `thenRn` \ ifaces ->
- let
- mod_map = iImpModInfo ifaces
- imp_names = iVSlurp ifaces
-
- -- mv_map groups together all the things imported from a particular module.
- mv_map :: FiniteMap ModuleName [(Name,Version)]
- mv_map = foldr add_mv emptyFM imp_names
-
- -- Build the result list by adding info for each module.
- -- For (a) a library module, we don't record it at all unless it contains orphans
- -- (We must never lose track of orphans.)
- --
- -- (b) a source-imported module, don't record the dependency at all
- --
- -- (b) may seem a bit strange. The idea is that the usages in a .hi file records
- -- *all* the module's dependencies other than the loop-breakers. We use
- -- this info in findAndReadInterface to decide whether to look for a .hi file or
- -- a .hi-boot file.
- --
- -- This means we won't track version changes, or orphans, from .hi-boot files.
- -- The former is potentially rather bad news. It could be fixed by recording
- -- whether something is a boot file along with the usage info for it, but
- -- I can't be bothered just now.
-
- mk_version_info mod_name (version, has_orphans, is_boot, contents) so_far
- = let
- go_for_it exports = (mod_name, version, has_orphans, is_boot, exports)
- : so_far
- in
- case contents of
- Nothing -> -- We didn't even open the interface
- -- This happens when a module, Foo, that we explicitly imported has
- -- 'import Baz' in its interface file, recording that Baz is below
- -- Foo in the module dependency hierarchy. We want to propagate this
- -- information. The Nothing says that we didn't even open the interface
- -- file but we must still propagate the dependeny info.
- go_for_it (Specifically [])
-
- Just (mod, _) -- We did open the interface
- | is_lib_module && not has_orphans
- -> so_far
-
- | is_lib_module -- Record the module but not detailed
- || mod_name `elem` export_all_mods -- version information for the imports
- -> go_for_it Everything
-
- | otherwise
- -> case lookupFM mv_map mod_name of
- Just whats_imported -> go_for_it (Specifically whats_imported)
- Nothing -> go_for_it (Specifically [])
- -- This happens if you have
- -- import Foo
- -- but don't actually *use* anything from Foo
- -- In which case record an empty dependency list
- where
- is_lib_module = isLibModule mod
-
- in
- -- A module shouldn't load its own interface
- -- This seems like a convenient place to check
- WARN( maybeToBool (lookupFM mod_map this_mod),
- ptext SLIT("Wierd:") <+> ppr this_mod <+> ptext SLIT("loads its own interface") )
+type RecompileRequired = Bool
+upToDate = False -- Recompile not required
+outOfDate = True -- Recompile required
+
+checkVersions :: Bool -- True <=> source unchanged
+ -> ModIface -- Old interface
+ -> TcRn m RecompileRequired
+checkVersions source_unchanged iface
+ | not source_unchanged
+ = returnM outOfDate
+ | otherwise
+ = traceHiDiffs (text "Considering whether compilation is required for" <+>
+ ppr (mi_module iface) <> colon) `thenM_`
+
+ -- Source code unchanged and no errors yet... carry on
+ -- First put the dependent-module info in the envt, just temporarily,
+ -- so that when we look for interfaces we look for the right one (.hi or .hi-boot)
+ -- It's just temporary because either the usage check will succeed
+ -- (in which case we are done with this module) or it'll fail (in which
+ -- case we'll compile the module from scratch anyhow).
+ updGblEnv (\ gbl -> gbl { tcg_imports = mod_deps }) (
+ checkList [checkModUsage u | u <- mi_usages iface]
+ )
- returnRn (foldFM mk_version_info [] mod_map)
where
- add_mv v@(name, version) mv_map
- = addToFM_C add_item mv_map mod [v]
- where
- mod = moduleName (nameModule name)
- add_item vs _ = (v:vs)
+ -- This is a bit of a hack really
+ mod_deps = emptyImportAvails { imp_dep_mods = mkModDeps (dep_mods (mi_deps iface)) }
+
+checkList :: [TcRn m RecompileRequired] -> TcRn m RecompileRequired
+checkList [] = returnM upToDate
+checkList (check:checks) = check `thenM` \ recompile ->
+ if recompile then
+ returnM outOfDate
+ else
+ checkList checks
\end{code}
-
+
\begin{code}
-getSlurped
- = getIfacesRn `thenRn` \ ifaces ->
- returnRn (iSlurp ifaces)
-
-recordSlurp maybe_version avail
--- Nothing for locally defined names
--- Just version for imported names
- = getIfacesRn `thenRn` \ ifaces@(Ifaces { iSlurp = slurped_names,
- iVSlurp = imp_names }) ->
+checkModUsage :: Usage Name -> TcRn m RecompileRequired
+-- Given the usage information extracted from the old
+-- M.hi file for the module being compiled, figure out
+-- whether M needs to be recompiled.
+
+checkModUsage (Usage { usg_name = mod_name, usg_mod = old_mod_vers,
+ usg_rules = old_rule_vers,
+ usg_exports = maybe_old_export_vers,
+ usg_entities = old_decl_vers })
+ = -- Load the imported interface is possible
let
- new_slurped_names = addAvailToNameSet slurped_names avail
-
- new_imp_names = case maybe_version of
- Just version -> (availName avail, version) : imp_names
- Nothing -> imp_names
+ doc_str = sep [ptext SLIT("need version info for"), ppr mod_name]
in
- setIfacesRn (ifaces { iSlurp = new_slurped_names,
- iVSlurp = new_imp_names })
-\end{code}
+ traceHiDiffs (text "Checking usages for module" <+> ppr mod_name) `thenM_`
+ tryM (loadInterface doc_str mod_name ImportBySystem) `thenM` \ mb_iface ->
-%*********************************************************
-%* *
-\subsection{Getting binders out of a declaration}
-%* *
-%*********************************************************
-
-@getDeclBinders@ returns the names for a @RdrNameHsDecl@.
-It's used for both source code (from @availsFromDecl@) and interface files
-(from @loadDecl@).
+ case mb_iface of {
+ Left exn -> (out_of_date (sep [ptext SLIT("Can't find version number for module"),
+ ppr mod_name]));
+ -- Couldn't find or parse a module mentioned in the
+ -- old interface file. Don't complain -- it might just be that
+ -- the current module doesn't need that import and it's been deleted
-It doesn't deal with source-code specific things: @ValD@, @DefD@. They
-are handled by the sourc-code specific stuff in @RnNames@.
-
-\begin{code}
-getDeclBinders :: (RdrName -> SrcLoc -> RnM d Name) -- New-name function
- -> RdrNameHsDecl
- -> RnM d (Maybe AvailInfo)
-
-getDeclBinders new_name (TyClD (TyData _ _ tycon _ condecls _ _ src_loc))
- = new_name tycon src_loc `thenRn` \ tycon_name ->
- getConFieldNames new_name condecls `thenRn` \ sub_names ->
- returnRn (Just (AvailTC tycon_name (tycon_name : nub sub_names)))
- -- The "nub" is because getConFieldNames can legitimately return duplicates,
- -- when a record declaration has the same field in multiple constructors
-
-getDeclBinders new_name (TyClD (TySynonym tycon _ _ src_loc))
- = new_name tycon src_loc `thenRn` \ tycon_name ->
- returnRn (Just (AvailTC tycon_name [tycon_name]))
-
-getDeclBinders new_name (TyClD (ClassDecl _ cname _ _ sigs _ _ _ _ _ _ src_loc))
- = new_name cname src_loc `thenRn` \ class_name ->
-
- -- Record the names for the class ops
+ Right iface ->
let
- -- just want class-op sigs
- op_sigs = filter isClassOpSig sigs
+ new_vers = mi_version iface
+ new_mod_vers = vers_module new_vers
+ new_decl_vers = vers_decls new_vers
+ new_export_vers = vers_exports new_vers
+ new_rule_vers = vers_rules new_vers
in
- mapRn (getClassOpNames new_name) op_sigs `thenRn` \ sub_names ->
-
- returnRn (Just (AvailTC class_name (class_name : sub_names)))
-
-getDeclBinders new_name (SigD (IfaceSig var ty prags src_loc))
- = new_name var src_loc `thenRn` \ var_name ->
- returnRn (Just (Avail var_name))
-
-getDeclBinders new_name (FixD _) = returnRn Nothing
-
- -- foreign declarations
-getDeclBinders new_name (ForD (ForeignDecl nm kind _ dyn _ loc))
- | binds_haskell_name kind dyn
- = new_name nm loc `thenRn` \ name ->
- returnRn (Just (Avail name))
-
- | otherwise -- a foreign export
- = lookupImplicitOccRn nm `thenRn_`
- returnRn Nothing
-
-getDeclBinders new_name (DefD _) = returnRn Nothing
-getDeclBinders new_name (InstD _) = returnRn Nothing
-getDeclBinders new_name (RuleD _) = returnRn Nothing
-
-binds_haskell_name (FoImport _) _ = True
-binds_haskell_name FoLabel _ = True
-binds_haskell_name FoExport ext_nm = isDynamicExtName ext_nm
-
-----------------
-getConFieldNames new_name (ConDecl con _ _ _ (RecCon fielddecls) src_loc : rest)
- = mapRn (\n -> new_name n src_loc) (con:fields) `thenRn` \ cfs ->
- getConFieldNames new_name rest `thenRn` \ ns ->
- returnRn (cfs ++ ns)
- where
- fields = concat (map fst fielddecls)
-
-getConFieldNames new_name (ConDecl con _ _ _ condecl src_loc : rest)
- = new_name con src_loc `thenRn` \ n ->
- (case condecl of
- NewCon _ (Just f) ->
- new_name f src_loc `thenRn` \ new_f ->
- returnRn [n,new_f]
- _ -> returnRn [n]) `thenRn` \ nn ->
- getConFieldNames new_name rest `thenRn` \ ns ->
- returnRn (nn ++ ns)
-
-getConFieldNames new_name [] = returnRn []
+ -- CHECK MODULE
+ checkModuleVersion old_mod_vers new_mod_vers `thenM` \ recompile ->
+ if not recompile then
+ returnM upToDate
+ else
+
+ -- CHECK EXPORT LIST
+ if checkExportList maybe_old_export_vers new_export_vers then
+ out_of_date_vers (ptext SLIT(" Export list changed"))
+ (fromJust maybe_old_export_vers)
+ new_export_vers
+ else
-getClassOpNames new_name (ClassOpSig op _ _ _ src_loc) = new_name op src_loc
-\end{code}
+ -- CHECK RULES
+ if old_rule_vers /= new_rule_vers then
+ out_of_date_vers (ptext SLIT(" Rules changed"))
+ old_rule_vers new_rule_vers
+ else
-@getDeclSysBinders@ gets the implicit binders introduced by a decl.
-A the moment that's just the tycon and datacon that come with a class decl.
-They aren't returned by @getDeclBinders@ because they aren't in scope;
-but they {\em should} be put into the @DeclsMap@ of this module.
+ -- CHECK ITEMS ONE BY ONE
+ checkList [checkEntityUsage new_decl_vers u | u <- old_decl_vers] `thenM` \ recompile ->
+ if recompile then
+ returnM outOfDate -- This one failed, so just bail out now
+ else
+ up_to_date (ptext SLIT(" Great! The bits I use are up to date"))
-Note that this excludes the default-method names of a class decl,
-and the dict fun of an instance decl, because both of these have
-bindings of their own elsewhere.
+ }
-\begin{code}
-getDeclSysBinders new_name (TyClD (ClassDecl _ cname _ _ sigs _ _ tname dname dwname snames src_loc))
- = sequenceRn [new_name n src_loc | n <- (tname : dname : dwname : snames)]
+------------------------
+checkModuleVersion old_mod_vers new_mod_vers
+ | new_mod_vers == old_mod_vers
+ = up_to_date (ptext SLIT("Module version unchanged"))
-getDeclSysBinders new_name (TyClD (TyData _ _ _ _ cons _ _ _))
- = sequenceRn [new_name wkr_name src_loc | ConDecl _ wkr_name _ _ _ src_loc <- cons]
+ | otherwise
+ = out_of_date_vers (ptext SLIT(" Module version has changed"))
+ old_mod_vers new_mod_vers
-getDeclSysBinders new_name other_decl
- = returnRn []
-\end{code}
+------------------------
+checkExportList Nothing new_vers = upToDate
+checkExportList (Just v) new_vers = v /= new_vers
-%*********************************************************
-%* *
-\subsection{Reading an interface file}
-%* *
-%*********************************************************
+------------------------
+checkEntityUsage new_vers (name,old_vers)
+ = case lookupNameEnv new_vers name of
-\begin{code}
-findAndReadIface :: SDoc -> ModuleName -> WhereFrom
- -> Bool -- Only relevant for SystemImport
- -- True <=> Look for a .hi file
- -- False <=> Look for .hi-boot file unless there's
- -- a library .hi file
- -> RnM d (Bool, Maybe (Module, ParsedIface))
- -- Bool is True if the interface actually read was a .hi-boot one
- -- Nothing <=> file not found, or unreadable, or illegible
- -- Just x <=> successfully found and parsed
-
-findAndReadIface doc_str mod_name from hi_file
- = traceRn trace_msg `thenRn_`
- -- we keep two maps for interface files,
- -- one for 'normal' ones, the other for .hi-boot files,
- -- hence the need to signal which kind we're interested.
-
- getHiMaps `thenRn` \ hi_maps ->
-
- case find_path from hi_maps of
- -- Found the file
- (hi_boot, Just (fpath, mod)) -> traceRn (ptext SLIT("...reading from") <+> text fpath)
- `thenRn_`
- readIface mod fpath `thenRn` \ result ->
- returnRn (hi_boot, result)
- (hi_boot, Nothing) -> traceRn (ptext SLIT("...not found")) `thenRn_`
- returnRn (hi_boot, Nothing)
- where
- find_path ImportByUser (hi_map, _) = (False, lookupFM hi_map mod_name)
- find_path ImportByUserSource (_, hiboot_map) = (True, lookupFM hiboot_map mod_name)
-
- find_path ImportBySystem (hi_map, hiboot_map)
- | hi_file
- = -- If the module we seek is in our dependent set,
- -- Look for a .hi file
- (False, lookupFM hi_map mod_name)
-
- | otherwise
- -- Check if there's a library module of that name
- -- If not, look for an hi-boot file
- = case lookupFM hi_map mod_name of
- stuff@(Just (_, mod)) | isLibModule mod -> (False, stuff)
- other -> (True, lookupFM hiboot_map mod_name)
-
- trace_msg = sep [hsep [ptext SLIT("Reading"),
- ppr from,
- ptext SLIT("interface for"),
- pprModuleName mod_name <> semi],
- nest 4 (ptext SLIT("reason:") <+> doc_str)]
+ Nothing -> -- We used it before, but it ain't there now
+ out_of_date (sep [ptext SLIT("No longer exported:"), ppr name])
+
+ Just new_vers -- It's there, but is it up to date?
+ | new_vers == old_vers -> traceHiDiffs (text " Up to date" <+> ppr name <+> parens (ppr new_vers)) `thenM_`
+ returnM upToDate
+ | otherwise -> out_of_date_vers (ptext SLIT(" Out of date:") <+> ppr name)
+ old_vers new_vers
+
+up_to_date msg = traceHiDiffs msg `thenM_` returnM upToDate
+out_of_date msg = traceHiDiffs msg `thenM_` returnM outOfDate
+out_of_date_vers msg old_vers new_vers
+ = out_of_date (hsep [msg, ppr old_vers, ptext SLIT("->"), ppr new_vers])
\end{code}
-@readIface@ tries just the one file.
-
-\begin{code}
-readIface :: Module -> String -> RnM d (Maybe (Module, ParsedIface))
- -- Nothing <=> file not found, or unreadable, or illegible
- -- Just x <=> successfully found and parsed
-readIface the_mod file_path
- = ioToRnM (hGetStringBuffer False file_path) `thenRn` \ read_result ->
- case read_result of
- Right contents ->
- case parseIface contents
- PState{ bol = 0#, atbol = 1#,
- context = [],
- glasgow_exts = 1#,
- loc = mkSrcLoc (mkFastString file_path) 1 } of
- POk _ (PIface mod_nm iface) ->
- warnCheckRn (mod_nm == moduleName the_mod)
- (hiModuleNameMismatchWarn the_mod mod_nm) `thenRn_`
- returnRn (Just (the_mod, iface))
-
- PFailed err -> failWithRn Nothing err
- other -> failWithRn Nothing (ptext SLIT("Unrecognisable interface file"))
- -- This last case can happen if the interface file is (say) empty
- -- in which case the parser thinks it looks like an IdInfo or
- -- something like that. Just an artefact of the fact that the
- -- parser is used for several purposes at once.
-
- Left err
- | isDoesNotExistError err -> returnRn Nothing
- | otherwise -> failWithRn Nothing (cannaeReadFile file_path err)
-\end{code}
%*********************************************************
%* *
%*********************************************************
\begin{code}
-noIfaceErr filename boot_file
- = hsep [ptext SLIT("Could not find valid"), boot,
- ptext SLIT("interface file"), quotes (pprModule filename)]
- where
- boot | boot_file = ptext SLIT("[boot]")
- | otherwise = empty
-
-cannaeReadFile file err
- = hcat [ptext SLIT("Failed in reading file: "),
- text file,
- ptext SLIT("; error="),
- text (show err)]
-
getDeclErr name
- = ptext SLIT("Failed to find interface decl for") <+> quotes (ppr name)
-
-getDeclWarn name loc
- = sep [ptext SLIT("Failed to find (optional) interface decl for") <+> quotes (ppr name),
- ptext SLIT("desired at") <+> ppr loc]
-
-importDeclWarn name
- = sep [ptext SLIT(
- "Compiler tried to import decl from interface file with same name as module."),
- ptext SLIT(
- "(possible cause: module name clashes with interface file already in scope.)")
- ] $$
- hsep [ptext SLIT("name:"), quotes (ppr name)]
-
-warnRedundantSourceImport mod_name
- = ptext SLIT("Unnecessary {- SOURCE -} in the import of module")
- <+> quotes (pprModuleName mod_name)
-
-hiModuleNameMismatchWarn :: Module -> ModuleName -> Message
-hiModuleNameMismatchWarn requested_mod mod_nm =
- hsep [ ptext SLIT("Something is amiss; requested module name")
- , pprModule requested_mod
- , ptext SLIT("differs from name found in the interface file ")
- , pprModuleName mod_nm
- ]
-
+ = vcat [ptext SLIT("Failed to find interface decl for") <+> quotes (ppr name),
+ ptext SLIT("from module") <+> quotes (ppr (nameModule name))
+ ]
\end{code}