-%********************************************************
-%* *
-\subsection{Checking usage information}
-%* *
-%********************************************************
-
-\begin{code}
-upToDate = True
-outOfDate = False
-
-checkModUsage :: [ImportVersion OccName] -> RnMG Bool
--- 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 [] = returnRn upToDate -- Yes! Everything is up to date!
-
-checkModUsage ((mod_name, _, _, NothingAtAll) : 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, _, _, whats_imported) : rest)
- = tryLoadInterface doc_str mod_name ImportBySystem `thenRn` \ (ifaces, maybe_err) ->
- case maybe_err of {
- Just err -> 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
-
- Nothing ->
- let
- (_, new_mod_vers, new_fix_vers, new_rule_vers, _, _)
- = case lookupFM (iImpModInfo ifaces) mod_name of
- Just (_, _, Just stuff) -> stuff
-
- old_mod_vers = case whats_imported of
- Everything v -> v
- Specifically v _ _ _ -> v
- -- NothingAtAll case dealt with by previous eqn for checkModUsage
- in
- -- 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:"), ppr mod_name])
- `thenRn_` checkModUsage rest
- else
- traceRn (sep [ptext SLIT("Module version has changed:"), ppr 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 { -- NothingAtAll dealt with earlier
-
- Everything _
- -> out_of_date (ptext SLIT("...and I needed the whole module")) ;
-
- Specifically _ old_fix_vers old_rule_vers old_local_vers ->
-
- if old_fix_vers /= new_fix_vers then
- out_of_date (ptext SLIT("Fixities changed"))
- else if old_rule_vers /= new_rule_vers then
- out_of_date (ptext SLIT("Rules changed"))
- else
- -- 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
- else
- returnRn outOfDate -- This one failed, so just bail out now
- }}
- where
- doc_str = sep [ptext SLIT("need version info for"), ppr mod_name]
-
-
-checkEntityUsage mod decls []
- = returnRn upToDate -- Yes! All up to date!
-
-checkEntityUsage mod decls ((occ_name,old_vers) : rest)
- = newGlobalName mod occ_name `thenRn` \ name ->
- case lookupNameEnv decls name of
-
- 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
- -- Up to date, so check the rest
- -> checkEntityUsage mod decls rest
-
- | otherwise
- -- Out of date, so bale out
- -> out_of_date (sep [ptext SLIT("Out of date:"), ppr name])
-
-out_of_date msg = traceRn msg `thenRn_` returnRn outOfDate
-\end{code}
-
-