\section[CompManager]{The Compilation Manager}
\begin{code}
-module CompManager ( cmInit, cmLoadModule,
+module CompManager ( cmInit, cmLoadModule, cmUnload,
+#ifdef GHCI
cmGetExpr, cmRunExpr,
+#endif
CmState, emptyCmState -- abstract
)
where
#include "HsVersions.h"
-import List ( nub )
-import Maybe ( catMaybes, maybeToList, fromMaybe )
-import Maybes ( maybeToBool )
-import Outputable
-import UniqFM ( emptyUFM, lookupUFM, addToUFM, delListFromUFM )
-import Digraph ( SCC(..), stronglyConnComp, flattenSCC, flattenSCCs )
-import Panic ( panic )
-
-import CmLink ( PersistentLinkerState, emptyPLS, Linkable(..),
- link, LinkResult(..),
- filterModuleLinkables, modname_of_linkable,
- is_package_linkable )
-import Interpreter ( HValue )
-import CmSummarise ( summarise, ModSummary(..),
- name_of_summary, deps_of_summary,
- mimp_name, ms_get_imports, is_source_import )
-import Module ( ModuleName, moduleName, packageOfModule,
- isModuleInThisPackage, PackageName, moduleEnvElts )
-import CmStaticInfo ( Package(..), PackageConfigInfo )
-import DriverPipeline ( compile, preprocess, doLink, CompResult(..) )
+import CmLink
+import CmTypes
+import HscTypes
+import Module ( Module, ModuleName, moduleName, isHomeModule,
+ mkModuleName, moduleNameUserString )
+import CmStaticInfo ( GhciMode(..) )
+import DriverPipeline
+import GetImports
import HscTypes ( HomeSymbolTable, HomeIfaceTable,
PersistentCompilerState, ModDetails(..) )
-import Name ( lookupNameEnv )
-import PrelNames ( mainName )
import HscMain ( initPersistentCompilerState )
-import Finder ( findModule, emptyHomeDirCache )
-import BasicTypes ( GhciMode(..) )
-import DriverUtil ( BarfKind(..) )
+import Finder
+import UniqFM ( emptyUFM, lookupUFM, addToUFM, delListFromUFM,
+ UniqFM, listToUFM )
+import Unique ( Uniquable )
+import Digraph ( SCC(..), stronglyConnComp, flattenSCC )
+import DriverFlags ( getDynFlags )
+import DriverPhases
+import DriverUtil ( splitFilename3 )
+import ErrUtils ( showPass )
+import Util
+import DriverUtil
+import TmpFiles
+import Outputable
+import Panic
+import CmdLineOpts ( DynFlags(..) )
+import IOExts
+
+#ifdef GHCI
+import Interpreter ( HValue )
+import HscMain ( hscExpr )
+import Type ( Type )
+import PrelGHC ( unsafeCoerce# )
+#endif
+
+-- lang
import Exception ( throwDyn )
-\end{code}
+-- std
+import Time ( ClockTime )
+import Directory ( getModificationTime, doesFileExist )
+import IO
+import Monad
+import List ( nub )
+import Maybe ( catMaybes, fromMaybe, isJust, fromJust )
+\end{code}
\begin{code}
-cmInit :: PackageConfigInfo -> IO CmState
-cmInit raw_package_info
- = emptyCmState raw_package_info
+cmInit :: GhciMode -> IO CmState
+cmInit gmode
+ = emptyCmState gmode
+#ifdef GHCI
cmGetExpr :: CmState
- -> ModuleName
+ -> DynFlags
+ -> Bool -- True <=> wrap in 'print' to get an IO-typed result
+ -> Module
-> String
- -> IO (CmState, Either [SDoc] HValue)
-cmGetExpr cmstate modhdl expr
- = return (panic "cmGetExpr:unimp")
-
+ -> IO (CmState, Maybe (HValue, PrintUnqualified, Type))
+cmGetExpr cmstate dflags wrap_io mod expr
+ = do (new_pcs, maybe_stuff) <-
+ hscExpr dflags wrap_io hst hit pcs mod expr
+ case maybe_stuff of
+ Nothing -> return (cmstate{ pcs=new_pcs }, Nothing)
+ Just (bcos, print_unqual, ty) -> do
+ hValue <- linkExpr pls bcos
+ return (cmstate{ pcs=new_pcs },
+ Just (hValue, print_unqual, ty))
+
+ -- ToDo: check that the module we passed in is sane/exists?
+ where
+ CmState{ hst=hst, hit=hit, pcs=pcs, pls=pls } = cmstate
+
+-- The HValue should represent a value of type IO () (Perhaps IO a?)
cmRunExpr :: HValue -> IO ()
cmRunExpr hval
- = return (panic "cmRunExpr:unimp")
-
-
--- Persistent state just for CM, excluding link & compile subsystems
-data PersistentCMState
- = PersistentCMState {
- hst :: HomeSymbolTable, -- home symbol table
- hit :: HomeIfaceTable, -- home interface table
- ui :: UnlinkedImage, -- the unlinked images
- mg :: ModuleGraph, -- the module graph
- pci :: PackageConfigInfo -- NEVER CHANGES
- }
-
-emptyPCMS :: PackageConfigInfo -> PersistentCMState
-emptyPCMS pci
- = PersistentCMState { hst = emptyHST, hit = emptyHIT,
- ui = emptyUI, mg = emptyMG, pci = pci }
+ = do unsafeCoerce# hval :: IO ()
+ -- putStrLn "done."
+#endif
emptyHIT :: HomeIfaceTable
emptyHIT = emptyUFM
emptyHST :: HomeSymbolTable
emptyHST = emptyUFM
-
-
-- Persistent state for the entire system
data CmState
= CmState {
- pcms :: PersistentCMState, -- CM's persistent state
+ hst :: HomeSymbolTable, -- home symbol table
+ hit :: HomeIfaceTable, -- home interface table
+ ui :: UnlinkedImage, -- the unlinked images
+ mg :: ModuleGraph, -- the module graph
+ gmode :: GhciMode, -- NEVER CHANGES
+
pcs :: PersistentCompilerState, -- compile's persistent state
pls :: PersistentLinkerState -- link's persistent state
}
-emptyCmState :: PackageConfigInfo -> IO CmState
-emptyCmState pci
- = do let pcms = emptyPCMS pci
- pcs <- initPersistentCompilerState
+emptyCmState :: GhciMode -> IO CmState
+emptyCmState gmode
+ = do pcs <- initPersistentCompilerState
pls <- emptyPLS
- return (CmState { pcms = pcms,
+ return (CmState { hst = emptyHST,
+ hit = emptyHIT,
+ ui = emptyUI,
+ mg = emptyMG,
+ gmode = gmode,
pcs = pcs,
pls = pls })
emptyUI :: UnlinkedImage
emptyUI = []
-type ModuleGraph = [SCC ModSummary] -- the module graph, topologically sorted
+type ModuleGraph = [ModSummary] -- the module graph, topologically sorted
emptyMG :: ModuleGraph
emptyMG = []
\end{code}
+Unload the compilation manager's state: everything it knows about the
+current collection of modules in the Home package.
+
+\begin{code}
+cmUnload :: CmState -> IO CmState
+cmUnload state
+ = do -- Throw away the old home dir cache
+ emptyHomeDirCache
+ -- Throw away the HIT and the HST
+ return state{ hst=new_hst, hit=new_hit, ui=emptyUI }
+ where
+ CmState{ hst=hst, hit=hit } = state
+ (new_hst, new_hit) = retainInTopLevelEnvs [] (hst,hit)
+\end{code}
+
The real business of the compilation manager: given a system state and
a module name, try and bring the module up to date, probably changing
the system state at the same time.
\begin{code}
cmLoadModule :: CmState
- -> ModuleName
- -> IO (CmState, Maybe ModuleName)
+ -> FilePath
+ -> IO (CmState, -- new state
+ Bool, -- was successful
+ [Module]) -- list of modules loaded
-cmLoadModule cmstate1 modname
+cmLoadModule cmstate1 rootname
= do -- version 1's are the original, before downsweep
- let pcms1 = pcms cmstate1
- let pls1 = pls cmstate1
- let pcs1 = pcs cmstate1
- let mg1 = mg pcms1
- let hst1 = hst pcms1
- let hit1 = hit pcms1
- let ui1 = ui pcms1
-
- let pcii = pci pcms1 -- this never changes
-
- -- do the downsweep to reestablish the module graph
- -- then generate version 2's by removing from HIT,HST,UI any
- -- modules in the old MG which are not in the new one.
-
- -- Throw away the old home dir cache
- emptyHomeDirCache
+ let pls1 = pls cmstate1
+ let pcs1 = pcs cmstate1
+ let hst1 = hst cmstate1
+ let hit1 = hit cmstate1
+ -- similarly, ui1 is the (complete) set of linkables from
+ -- the previous pass, if any.
+ let ui1 = ui cmstate1
+ let mg1 = mg cmstate1
+
+ let ghci_mode = gmode cmstate1 -- this never changes
+
+ -- Do the downsweep to reestablish the module graph
+ -- then generate version 2's by retaining in HIT,HST,UI a
+ -- stable set S of modules, as defined below.
+
+ dflags <- getDynFlags
+ let verb = verbosity dflags
+
+ showPass dflags "Chasing dependencies"
+ when (verb >= 1 && ghci_mode == Batch) $
+ hPutStrLn stderr (progName ++ ": chasing modules from: " ++ rootname)
+
+ (mg2unsorted, a_root_is_Main) <- downsweep [rootname] mg1
+ let mg2unsorted_names = map name_of_summary mg2unsorted
+
+ -- reachable_from follows source as well as normal imports
+ let reachable_from :: ModuleName -> [ModuleName]
+ reachable_from = downwards_closure_of_module mg2unsorted
+
+ -- should be cycle free; ignores 'import source's
+ let mg2 = topological_sort False mg2unsorted
+ -- ... whereas this takes them into account. Used for
+ -- backing out partially complete cycles following a failed
+ -- upsweep, and for removing from hst/hit all the modules
+ -- not in strict downwards closure, during calls to compile.
+ let mg2_with_srcimps = topological_sort True mg2unsorted
+
+ -- Sort out which linkables we wish to keep in the unlinked image.
+ -- See getValidLinkables below for details.
+ valid_linkables <- getValidLinkables ui1 mg2unsorted_names
+ mg2_with_srcimps
+
+ -- Figure out a stable set of modules which can be retained
+ -- the top level envs, to avoid upsweeping them. Goes to a
+ -- bit of trouble to avoid upsweeping module cycles.
+ --
+ -- Construct a set S of stable modules like this:
+ -- Travel upwards, over the sccified graph. For each scc
+ -- of modules ms, add ms to S only if:
+ -- 1. All home imports of ms are either in ms or S
+ -- 2. A valid linkable exists for each module in ms
+
+ stable_mods
+ <- preUpsweep valid_linkables ui1 mg2unsorted_names
+ [] mg2_with_srcimps
+
+ let stable_summaries
+ = concatMap (findInSummaries mg2unsorted) stable_mods
+
+ stable_linkables
+ = filter (\m -> linkableModName m `elem` stable_mods)
+ valid_linkables
+
+ when (verb >= 2) $
+ putStrLn (showSDoc (text "STABLE MODULES:"
+ <+> sep (map (text.moduleNameUserString) stable_mods)))
+
+ -- unload any modules which aren't going to be re-linked this
+ -- time around.
+ pls2 <- unload ghci_mode dflags stable_linkables pls1
+
+ -- We could at this point detect cycles which aren't broken by
+ -- a source-import, and complain immediately, but it seems better
+ -- to let upsweep_mods do this, so at least some useful work gets
+ -- done before the upsweep is abandoned.
+ let upsweep_these
+ = filter (\scc -> any (`notElem` stable_mods)
+ (map name_of_summary (flattenSCC scc)))
+ mg2
+
+ --hPutStrLn stderr "after tsort:\n"
+ --hPutStrLn stderr (showSDoc (vcat (map ppr mg2)))
+
+ -- Because we don't take into account source imports when doing
+ -- the topological sort, there shouldn't be any cycles in mg2.
+ -- If there is, we complain and give up -- the user needs to
+ -- break the cycle using a boot file.
- putStr "cmLoadModule: downsweep begins\n"
- mg2unsorted <- downsweep modname
-
- let modnames1 = map name_of_summary (flattenSCCs mg1)
- let modnames2 = map name_of_summary mg2unsorted
- let mods_to_zap = filter (`notElem` modnames2) modnames1
-
- let (hst2, hit2, ui2)
- = removeFromTopLevelEnvs mods_to_zap (hst1, hit1, ui1)
+ -- Now do the upsweep, calling compile for each module in
+ -- turn. Final result is version 3 of everything.
- let mg2 = topological_sort mg2unsorted
+ let threaded2 = CmThreaded pcs1 hst1 hit1
- putStrLn "after tsort:\n"
- putStrLn (showSDoc (vcat (map ppr ({-flattenSCCs-} mg2))))
+ (upsweep_complete_success, threaded3, modsUpswept, newLis)
+ <- upsweep_mods ghci_mode dflags valid_linkables reachable_from
+ threaded2 upsweep_these
- -- Now do the upsweep, calling compile for each module in
- -- turn. Final result is version 3 of everything.
+ let ui3 = add_to_ui valid_linkables newLis
+ let (CmThreaded pcs3 hst3 hit3) = threaded3
- let threaded2 = ModThreaded pcs1 hst2 hit2
+ -- At this point, modsUpswept and newLis should have the same
+ -- length, so there is one new (or old) linkable for each
+ -- mod which was processed (passed to compile).
- (upsweepOK, threaded3, sccOKs, newLis)
- <- upsweep_sccs threaded2 [] [] mg2
+ -- Make modsDone be the summaries for each home module now
+ -- available; this should equal the domains of hst3 and hit3.
+ -- (NOT STRICTLY TRUE if an interactive session was started
+ -- with some object on disk ???)
+ -- Get in in a roughly top .. bottom order (hence reverse).
- let ui3 = add_to_ui ui2 newLis
- let (ModThreaded pcs3 hst3 hit3) = threaded3
+ let modsDone = reverse modsUpswept ++ stable_summaries
-- Try and do linking in some form, depending on whether the
-- upsweep was completely or only partially successful.
- let ghci_mode = Batch -- ToDo: fix!
- if upsweepOK
+ if upsweep_complete_success
then
- do putStrLn "UPSWEEP COMPLETELY SUCCESSFUL"
- let someone_exports_main = any exports_main (moduleEnvElts hst3)
- let mods_to_relink = upwards_closure mg2
- (map modname_of_linkable newLis)
- pkg_linkables <- find_pkg_linkables_for pcii
- mg2 mods_to_relink
- putStrLn ("needed package modules =\n"
- ++ showSDoc (vcat (map ppr pkg_linkables)))
- let sccs_to_relink = group_uis ui3 mg2 mods_to_relink
- let all_to_relink = map AcyclicSCC pkg_linkables
- ++ sccs_to_relink
- linkresult <- link doLink ghci_mode someone_exports_main
- pcii all_to_relink pls1
+ -- Easy; just relink it all.
+ do when (verb >= 2) $
+ hPutStrLn stderr "Upsweep completely successful."
+
+ -- clean up after ourselves
+ cleanTempFilesExcept verb (ppFilesFromSummaries modsDone)
+
+ linkresult
+ <- link ghci_mode dflags a_root_is_Main ui3 pls2
case linkresult of
LinkErrs _ _
-> panic "cmLoadModule: link failed (1)"
LinkOK pls3
- -> do let pcms3 = PersistentCMState { hst=hst3, hit=hit3,
- ui=ui3, mg=mg2, pci=pcii }
- let cmstate3
- = CmState { pcms=pcms3, pcs=pcs3, pls=pls3 }
- return (cmstate3, Just modname)
+ -> do let cmstate3
+ = CmState { hst=hst3, hit=hit3,
+ ui=ui3, mg=modsDone,
+ gmode=ghci_mode,
+ pcs=pcs3, pls=pls3 }
+ return (cmstate3, True,
+ map ms_mod modsDone)
else
- do putStrLn "UPSWEEP PARTIALLY SUCCESSFUL"
- let mods_to_relink = downwards_closure mg2
- (map name_of_summary (flattenSCCs sccOKs))
- pkg_linkables <- find_pkg_linkables_for pcii
- mg2 mods_to_relink
- let sccs_to_relink = group_uis ui3 mg2 mods_to_relink
- let all_to_relink = map AcyclicSCC pkg_linkables
- ++ sccs_to_relink
- linkresult <- link doLink ghci_mode False pcii all_to_relink pls1
+ -- Tricky. We need to back out the effects of compiling any
+ -- half-done cycles, both so as to clean up the top level envs
+ -- and to avoid telling the interactive linker to link them.
+ do when (verb >= 2) $
+ hPutStrLn stderr "Upsweep partially successful."
+
+ let modsDone_names
+ = map name_of_summary modsDone
+ let mods_to_zap_names
+ = findPartiallyCompletedCycles modsDone_names mg2_with_srcimps
let (hst4, hit4, ui4)
- = removeFromTopLevelEnvs mods_to_relink (hst3,hit3,ui3)
+ = removeFromTopLevelEnvs mods_to_zap_names (hst3,hit3,ui3)
+ let mods_to_keep
+ = filter ((`notElem` mods_to_zap_names).name_of_summary) modsDone
+ let mods_to_keep_names
+ = map name_of_summary mods_to_keep
+ -- we could get the relevant linkables by filtering newLis, but
+ -- it seems easier to drag them out of the updated, cleaned-up UI
+ let linkables_to_link
+ = map (unJust "linkables_to_link" . findModuleLinkable_maybe ui4)
+ mods_to_keep_names
+
+ -- clean up after ourselves
+ cleanTempFilesExcept verb (ppFilesFromSummaries mods_to_keep)
+
+ linkresult <- link ghci_mode dflags False linkables_to_link pls2
case linkresult of
LinkErrs _ _
-> panic "cmLoadModule: link failed (2)"
- LinkOK pls4
- -> do let pcms4 = PersistentCMState { hst=hst4, hit=hit4,
- ui=ui4, mg=mg2, pci=pcii }
- let cmstate4
- = CmState { pcms=pcms4, pcs=pcs3, pls=pls4 }
- return (cmstate4, Just modname)
-
-exports_main :: ModDetails -> Bool
-exports_main md
- = maybeToBool (lookupNameEnv (md_types md) mainName)
-
--- Given a (home) module graph and a bunch of names of (home) modules
--- within that graph, return the names of any packages needed by the
--- named modules. Do this by looking at their imports. Assumes, and
--- checks, that all of "mods" are mentioned in "mg".
---
--- Then, having found the packages directly needed by "mods",
--- (1) round up, by looking in "pci", all packages they directly or
--- indirectly depend on, and (2) put these packages in topological
--- order, since that's important for some linkers. Since cycles in
--- the package dependency graph aren't allowed, we can just return
--- the list of (package) linkables, rather than a list of SCCs.
-find_pkg_linkables_for :: PackageConfigInfo -> [SCC ModSummary] -> [ModuleName]
- -> IO [Linkable]
-find_pkg_linkables_for pcii mg mods
- = let mg_summaries = flattenSCCs mg
- mg_names = map name_of_summary mg_summaries
- in
- -- Assert that the modules for which we seek the required packages
- -- are all in the module graph, i.e. are all home modules.
- if not (all (`elem` mg_names) mods)
- then panic "find_pkg_linkables_for"
- else
- do let all_imports
- = concat
- [deps_of_summary summ
- | summ <- mg_summaries, name_of_summary summ `elem` mods]
- let imports_not_in_home -- imports which must be from packages
- = nub (filter (`notElem` mg_names) all_imports)
-
- -- Figure out the packages directly imported by the home modules
- maybe_locs_n_mods <- mapM findModule imports_not_in_home
- let home_pkgs_needed
- = nub (concatMap get_pkg maybe_locs_n_mods)
- where get_pkg Nothing = []
- get_pkg (Just (mod, loc))
- = case packageOfModule mod of
- Just p -> [p]; _ -> []
-
- -- Discover the package dependency graph, and use it to find the
- -- transitive closure of all the needed packages
- let pkg_depend_graph :: [(PackageName,[PackageName])]
- pkg_depend_graph = map (\pkg -> (_PK_ (name pkg), map _PK_ (package_deps pkg))) pcii
-
- let all_pkgs_needed = simple_transitive_closure
- pkg_depend_graph home_pkgs_needed
-
- -- Make a graph, in the style which Digraph.stronglyConnComp expects,
- -- containing entries only for the needed packages.
- let needed_graph
- = concat
- [if srcP `elem` all_pkgs_needed
- then [(srcP, srcP, dstsP)]
- else []
- | (srcP, dstsP) <- pkg_depend_graph]
- tsorted = flattenSCCs (stronglyConnComp needed_graph)
-
- return (map LP tsorted)
-
-
-simple_transitive_closure :: Eq a => [(a,[a])] -> [a] -> [a]
-simple_transitive_closure graph set
- = let set2 = nub (concatMap dsts set ++ set)
- dsts node = fromMaybe [] (lookup node graph)
- in
- if length set == length set2
- then set
- else simple_transitive_closure graph set2
-
-
--- For each module in mods_to_group, extract the relevant linkable
--- out of "ui", and arrange these linkables in SCCs as defined by modGraph.
--- All this is so that we can pass SCCified Linkable groups to the
--- linker. A constraint that should be recorded somewhere is that
--- all sccs should either be all-interpreted or all-object, not a mixture.
-group_uis :: UnlinkedImage -> [SCC ModSummary] -> [ModuleName] -> [SCC Linkable]
-group_uis ui modGraph mods_to_group
- = map extract (cleanup (fishOut modGraph mods_to_group))
+ LinkOK pls3
+ -> do let cmstate4
+ = CmState { hst=hst4, hit=hit4,
+ ui=ui4, mg=mods_to_keep,
+ gmode=ghci_mode, pcs=pcs3, pls=pls3 }
+ return (cmstate4, False,
+ map ms_mod mods_to_keep)
+
+
+ppFilesFromSummaries summaries
+ = [ fn | Just fn <- map (ml_hspp_file . ms_location) summaries ]
+
+-----------------------------------------------------------------------------
+-- getValidLinkables
+
+-- For each module (or SCC of modules), we take:
+--
+-- - the old in-core linkable, if available
+-- - an on-disk linkable, if available
+--
+-- and we take the youngest of these, provided it is younger than the
+-- source file. We ignore the on-disk linkables unless all of the
+-- dependents of this SCC also have on-disk linkables.
+--
+-- If a module has a valid linkable, then it may be STABLE (see below),
+-- and it is classified as SOURCE UNCHANGED for the purposes of calling
+-- compile.
+--
+-- ToDo: this pass could be merged with the preUpsweep.
+
+getValidLinkables
+ :: [Linkable] -- old linkables
+ -> [ModuleName] -- all home modules
+ -> [SCC ModSummary] -- all modules in the program, dependency order
+ -> IO [Linkable] -- still-valid linkables
+
+getValidLinkables old_linkables all_home_mods module_graph
+ = foldM (getValidLinkablesSCC old_linkables all_home_mods) [] module_graph
+
+getValidLinkablesSCC old_linkables all_home_mods new_linkables scc0
+ = let
+ scc = flattenSCC scc0
+ scc_names = map name_of_summary scc
+ home_module m = m `elem` all_home_mods && m `notElem` scc_names
+ scc_allhomeimps = nub (filter home_module (concatMap ms_allimps scc))
+
+ has_object m = case findModuleLinkable_maybe new_linkables m of
+ Nothing -> False
+ Just l -> isObjectLinkable l
+
+ objects_allowed = all has_object scc_allhomeimps
+ in do
+
+ these_linkables
+ <- foldM (getValidLinkable old_linkables objects_allowed) [] scc
+
+ -- since an scc can contain only all objects or no objects at all,
+ -- we have to check whether we got all objects or not, and re-do
+ -- the linkable check if not.
+ adjusted_linkables
+ <- if objects_allowed && not (all isObjectLinkable these_linkables)
+ then foldM (getValidLinkable old_linkables False) [] scc
+ else return these_linkables
+
+ return (adjusted_linkables ++ new_linkables)
+
+
+getValidLinkable :: [Linkable] -> Bool -> [Linkable] -> ModSummary
+ -> IO [Linkable]
+getValidLinkable old_linkables objects_allowed new_linkables summary
+ = do
+ let mod_name = name_of_summary summary
+
+ maybe_disk_linkable
+ <- if (not objects_allowed)
+ then return Nothing
+ else case ml_obj_file (ms_location summary) of
+ Just obj_fn -> maybe_getFileLinkable mod_name obj_fn
+ Nothing -> return Nothing
+
+ -- find an old in-core linkable if we have one. (forget about
+ -- on-disk linkables for now, we'll check again whether there's
+ -- one here below, just in case a new one has popped up recently).
+ let old_linkable = findModuleLinkable_maybe old_linkables mod_name
+ maybe_old_linkable =
+ case old_linkable of
+ Just (LM _ _ ls) | all isInterpretable ls -> old_linkable
+ _ -> Nothing
+
+ -- The most recent of the old UI linkable or whatever we could
+ -- find on disk is returned as the linkable if compile
+ -- doesn't think we need to recompile.
+ let linkable_list
+ = case (maybe_old_linkable, maybe_disk_linkable) of
+ (Nothing, Nothing) -> []
+ (Nothing, Just di) -> [di]
+ (Just ui, Nothing) -> [ui]
+ (Just ui, Just di)
+ | linkableTime ui >= linkableTime di -> [ui]
+ | otherwise -> [di]
+
+ -- only linkables newer than the source code are valid
+ let maybe_src_date = ms_hs_date summary
+
+ valid_linkable_list
+ = case maybe_src_date of
+ Nothing -> panic "valid_linkable_list"
+ Just src_date
+ -> filter (\li -> linkableTime li > src_date) linkable_list
+
+ return (valid_linkable_list ++ new_linkables)
+
+
+maybe_getFileLinkable :: ModuleName -> FilePath -> IO (Maybe Linkable)
+maybe_getFileLinkable mod_name obj_fn
+ = do obj_exist <- doesFileExist obj_fn
+ if not obj_exist
+ then return Nothing
+ else
+ do let stub_fn = case splitFilename3 obj_fn of
+ (dir, base, ext) -> dir ++ "/" ++ base ++ ".stub_o"
+ stub_exist <- doesFileExist stub_fn
+ obj_time <- getModificationTime obj_fn
+ if stub_exist
+ then return (Just (LM obj_time mod_name [DotO obj_fn, DotO stub_fn]))
+ else return (Just (LM obj_time mod_name [DotO obj_fn]))
+
+
+-----------------------------------------------------------------------------
+-- Do a pre-upsweep without use of "compile", to establish a
+-- (downward-closed) set of stable modules for which we won't call compile.
+
+preUpsweep :: [Linkable] -- new valid linkables
+ -> [Linkable] -- old linkables
+ -> [ModuleName] -- names of all mods encountered in downsweep
+ -> [ModuleName] -- accumulating stable modules
+ -> [SCC ModSummary] -- scc-ified mod graph, including src imps
+ -> IO [ModuleName] -- stable modules
+
+preUpsweep valid_lis old_lis all_home_mods stable []
+ = return stable
+preUpsweep valid_lis old_lis all_home_mods stable (scc0:sccs)
+ = do let scc = flattenSCC scc0
+ scc_allhomeimps :: [ModuleName]
+ scc_allhomeimps
+ = nub (filter (`elem` all_home_mods) (concatMap ms_allimps scc))
+ all_imports_in_scc_or_stable
+ = all in_stable_or_scc scc_allhomeimps
+ scc_names
+ = map name_of_summary scc
+ in_stable_or_scc m
+ = m `elem` scc_names || m `elem` stable
+
+ -- now we check for valid linkables: each module in the SCC must
+ -- have a valid linkable (see getValidLinkables above), and the
+ -- newest linkable must be the same as the previous linkable for
+ -- this module (if one exists).
+ has_valid_linkable new_summary
+ = case findModuleLinkable_maybe valid_lis modname of
+ Nothing -> False
+ Just l -> case findModuleLinkable_maybe old_lis modname of
+ Nothing -> True
+ Just m -> linkableTime l == linkableTime m
+ where modname = name_of_summary new_summary
+
+ scc_is_stable = all_imports_in_scc_or_stable
+ && all has_valid_linkable scc
+
+ if scc_is_stable
+ then preUpsweep valid_lis old_lis all_home_mods
+ (scc_names++stable) sccs
+ else preUpsweep valid_lis old_lis all_home_mods
+ stable sccs
+
+ where
+
+
+-- Helper for preUpsweep. Assuming that new_summary's imports are all
+-- stable (in the sense of preUpsweep), determine if new_summary is itself
+-- stable, and, if so, in batch mode, return its linkable.
+findInSummaries :: [ModSummary] -> ModuleName -> [ModSummary]
+findInSummaries old_summaries mod_name
+ = [s | s <- old_summaries, name_of_summary s == mod_name]
+
+findModInSummaries :: [ModSummary] -> Module -> Maybe ModSummary
+findModInSummaries old_summaries mod
+ = case [s | s <- old_summaries, ms_mod s == mod] of
+ [] -> Nothing
+ (s:_) -> Just s
+
+-- Return (names of) all those in modsDone who are part of a cycle
+-- as defined by theGraph.
+findPartiallyCompletedCycles :: [ModuleName] -> [SCC ModSummary] -> [ModuleName]
+findPartiallyCompletedCycles modsDone theGraph
+ = chew theGraph
where
- fishOut :: [SCC ModSummary] -> [ModuleName] -> [(Bool,[ModuleName])]
- fishOut [] unused
- | null unused = []
- | otherwise = panic "group_uis: modnames not in modgraph"
- fishOut ((AcyclicSCC ms):sccs) unused
- = case split (== (name_of_summary ms)) unused of
- (eq, not_eq) -> (False, eq) : fishOut sccs not_eq
- fishOut ((CyclicSCC mss):sccs) unused
- = case split (`elem` (map name_of_summary mss)) unused of
- (eq, not_eq) -> (True, eq) : fishOut sccs not_eq
-
- cleanup :: [(Bool,[ModuleName])] -> [SCC ModuleName]
- cleanup [] = []
- cleanup ((isRec,names):rest)
- | null names = cleanup rest
- | isRec = CyclicSCC names : cleanup rest
- | not isRec = case names of [name] -> AcyclicSCC name : cleanup rest
- other -> panic "group_uis(cleanup)"
-
- extract :: SCC ModuleName -> SCC Linkable
- extract (AcyclicSCC nm) = AcyclicSCC (getLi nm)
- extract (CyclicSCC nms) = CyclicSCC (map getLi nms)
-
- getLi nm = case [li | li <- ui, not (is_package_linkable li),
- nm == modname_of_linkable li] of
- [li] -> li
- other -> panic "group_uis:getLi"
-
- split f xs = (filter f xs, filter (not.f) xs)
+ chew [] = []
+ chew ((AcyclicSCC v):rest) = chew rest -- acyclic? not interesting.
+ chew ((CyclicSCC vs):rest)
+ = let names_in_this_cycle = nub (map name_of_summary vs)
+ mods_in_this_cycle
+ = nub ([done | done <- modsDone,
+ done `elem` names_in_this_cycle])
+ chewed_rest = chew rest
+ in
+ if not (null mods_in_this_cycle)
+ && length mods_in_this_cycle < length names_in_this_cycle
+ then mods_in_this_cycle ++ chewed_rest
+ else chewed_rest
-- Add the given (LM-form) Linkables to the UI, overwriting previous
-- versions if they exist.
add_to_ui :: UnlinkedImage -> [Linkable] -> UnlinkedImage
add_to_ui ui lis
- = foldr add1 ui lis
+ = filter (not_in lis) ui ++ lis
where
- add1 :: Linkable -> UnlinkedImage -> UnlinkedImage
- add1 li ui
- = li : filter (\li2 -> not (for_same_module li li2)) ui
-
- for_same_module :: Linkable -> Linkable -> Bool
- for_same_module li1 li2
- = not (is_package_linkable li1)
- && not (is_package_linkable li2)
- && modname_of_linkable li1 == modname_of_linkable li2
+ not_in :: [Linkable] -> Linkable -> Bool
+ not_in lis li
+ = all (\l -> linkableModName l /= mod) lis
+ where mod = linkableModName li
--- Compute upwards and downwards closures in the (home-) module graph.
-downwards_closure,
- upwards_closure :: [SCC ModSummary] -> [ModuleName] -> [ModuleName]
-
-upwards_closure = up_down_closure True
-downwards_closure = up_down_closure False
-
-up_down_closure :: Bool -> [SCC ModSummary] -> [ModuleName] -> [ModuleName]
-up_down_closure up modGraph roots
- = let mgFlat = flattenSCCs modGraph
- nodes = map name_of_summary mgFlat
-
- fwdEdges, backEdges :: [(ModuleName, [ModuleName])]
- -- have an entry for each mod in mgFlat, and do not
- -- mention edges leading out of the home package
- fwdEdges
- = map mkEdge mgFlat
- backEdges -- Only calculated if needed, which is just as well!
- = [(n, [m | (m, m_imports) <- fwdEdges, n `elem` m_imports])
- | (n, n_imports) <- fwdEdges]
-
- mkEdge summ
- = (name_of_summary summ,
- -- ignore imports not from the home package
- filter (`elem` nodes) (deps_of_summary summ))
- in
- simple_transitive_closure
- (if up then backEdges else fwdEdges) (nub roots)
-
-
+data CmThreaded -- stuff threaded through individual module compilations
+ = CmThreaded PersistentCompilerState HomeSymbolTable HomeIfaceTable
-data ModThreaded -- stuff threaded through individual module compilations
- = ModThreaded PersistentCompilerState HomeSymbolTable HomeIfaceTable
--- Compile multiple SCCs, stopping as soon as an error appears
-upsweep_sccs :: ModThreaded -- PCS & HST & HIT
- -> [SCC ModSummary] -- accum: SCCs which succeeded
- -> [Linkable] -- accum: new Linkables
- -> [SCC ModSummary] -- SCCs to do (the worklist)
+-- Compile multiple modules, stopping as soon as an error appears.
+-- There better had not be any cyclic groups here -- we check for them.
+upsweep_mods :: GhciMode
+ -> DynFlags
+ -> UnlinkedImage -- valid linkables
+ -> (ModuleName -> [ModuleName]) -- to construct downward closures
+ -> CmThreaded -- PCS & HST & HIT
+ -> [SCC ModSummary] -- mods to do (the worklist)
-- ...... RETURNING ......
- -> IO (Bool{-success?-},
- ModThreaded,
- [SCC ModSummary], -- SCCs which succeeded
+ -> IO (Bool{-complete success?-},
+ CmThreaded,
+ [ModSummary], -- mods which succeeded
[Linkable]) -- new linkables
-upsweep_sccs threaded sccOKs newLis []
- = -- No more SCCs to do.
- return (True, threaded, sccOKs, newLis)
-
-upsweep_sccs threaded sccOKs newLis (scc:sccs)
- = -- Start work on a new SCC.
- do (sccOK, threaded2, lisSCC)
- <- upsweep_scc threaded (flattenSCC scc)
- if sccOK
- then -- all the modules in the scc were ok
- -- move on to the next SCC
- upsweep_sccs threaded2
- (scc:sccOKs) (lisSCC++newLis) sccs
- else -- we got a compilation error; give up now
- return
- (False, threaded2, sccOKs, lisSCC++newLis)
-
-
--- Compile multiple modules (one SCC), stopping as soon as an error appears
-upsweep_scc :: ModThreaded
- -> [ModSummary]
- -> IO (Bool{-success?-}, ModThreaded, [Linkable])
-upsweep_scc threaded []
- = return (True, threaded, [])
-upsweep_scc threaded (mod:mods)
- = do (moduleOK, threaded1, maybe_linkable)
- <- upsweep_mod threaded mod
- if moduleOK
- then -- No errors; get contribs from the rest
- do (restOK, threaded2, linkables)
- <- upsweep_scc threaded1 mods
- return
- (restOK, threaded2, maybeToList maybe_linkable ++ linkables)
- else -- Errors; give up _now_
- return (False, threaded1, [])
-
--- Compile a single module.
-upsweep_mod :: ModThreaded
+upsweep_mods ghci_mode dflags oldUI reachable_from threaded
+ []
+ = return (True, threaded, [], [])
+
+upsweep_mods ghci_mode dflags oldUI reachable_from threaded
+ ((CyclicSCC ms):_)
+ = do hPutStrLn stderr ("Module imports form a cycle for modules:\n\t" ++
+ unwords (map (moduleNameUserString.name_of_summary) ms))
+ return (False, threaded, [], [])
+
+upsweep_mods ghci_mode dflags oldUI reachable_from threaded
+ ((AcyclicSCC mod):mods)
+ = do --case threaded of
+ -- CmThreaded pcsz hstz hitz
+ -- -> putStrLn ("UPSWEEP_MOD: hit = " ++ show (map (moduleNameUserString.moduleName.mi_module) (eltsUFM hitz)))
+
+ (threaded1, maybe_linkable)
+ <- upsweep_mod ghci_mode dflags oldUI threaded mod
+ (reachable_from (name_of_summary mod))
+ case maybe_linkable of
+ Just linkable
+ -> -- No errors; do the rest
+ do (restOK, threaded2, modOKs, linkables)
+ <- upsweep_mods ghci_mode dflags oldUI reachable_from
+ threaded1 mods
+ return (restOK, threaded2, mod:modOKs, linkable:linkables)
+ Nothing -- we got a compilation error; give up now
+ -> return (False, threaded1, [], [])
+
+
+-- Compile a single module. Always produce a Linkable for it if
+-- successful. If no compilation happened, return the old Linkable.
+upsweep_mod :: GhciMode
+ -> DynFlags
+ -> UnlinkedImage
+ -> CmThreaded
-> ModSummary
- -> IO (Bool{-success?-}, ModThreaded, Maybe Linkable)
+ -> [ModuleName]
+ -> IO (CmThreaded, Maybe Linkable)
+
+upsweep_mod ghci_mode dflags oldUI threaded1 summary1 reachable_from_here
+ = do
+ let mod_name = name_of_summary summary1
+ let verb = verbosity dflags
+
+ when (verb == 1) $
+ if (ghci_mode == Batch)
+ then hPutStr stderr (progName ++ ": module "
+ ++ moduleNameUserString mod_name
+ ++ ": ")
+ else hPutStr stderr ("Compiling "
+ ++ moduleNameUserString mod_name
+ ++ " ... ")
+
+ let (CmThreaded pcs1 hst1 hit1) = threaded1
+ let old_iface = lookupUFM hit1 mod_name
+
+ let maybe_old_linkable = findModuleLinkable_maybe oldUI mod_name
+
+ source_unchanged = isJust maybe_old_linkable
+
+ (hst1_strictDC, hit1_strictDC)
+ = retainInTopLevelEnvs
+ (filter (/= (name_of_summary summary1)) reachable_from_here)
+ (hst1,hit1)
+
+ old_linkable
+ = unJust "upsweep_mod:old_linkable" maybe_old_linkable
-upsweep_mod threaded1 summary1
- = do let mod_name = name_of_summary summary1
- let (ModThreaded pcs1 hst1 hit1) = threaded1
- let old_iface = lookupUFM hit1 (name_of_summary summary1)
- compresult <- compile summary1 old_iface hst1 hit1 pcs1
+ compresult <- compile ghci_mode summary1 source_unchanged
+ old_iface hst1_strictDC hit1_strictDC pcs1
case compresult of
- -- Compilation "succeeded", but didn't return a new iface or
+ -- Compilation "succeeded", but didn't return a new
-- linkable, meaning that compilation wasn't needed, and the
-- new details were manufactured from the old iface.
- CompOK details Nothing pcs2
- -> let hst2 = addToUFM hst1 mod_name details
- hit2 = hit1
- threaded2 = ModThreaded pcs2 hst2 hit2
- in return (True, threaded2, Nothing)
+ CompOK pcs2 new_details new_iface Nothing
+ -> do let hst2 = addToUFM hst1 mod_name new_details
+ hit2 = addToUFM hit1 mod_name new_iface
+ threaded2 = CmThreaded pcs2 hst2 hit2
+
+ if ghci_mode == Interactive && verb >= 1 then
+ -- if we're using an object file, tell the user
+ case old_linkable of
+ (LM _ _ objs@(DotO _:_))
+ -> do hPutStrLn stderr (showSDoc (space <>
+ parens (hsep (text "using":
+ punctuate comma
+ [ text o | DotO o <- objs ]))))
+ _ -> return ()
+ else
+ return ()
+
+ return (threaded2, Just old_linkable)
-- Compilation really did happen, and succeeded. A new
-- details, iface and linkable are returned.
- CompOK details (Just (new_iface, new_linkable)) pcs2
- -> let hst2 = addToUFM hst1 mod_name details
- hit2 = addToUFM hit1 mod_name new_iface
- threaded2 = ModThreaded pcs2 hst2 hit2
- in return (True, threaded2, Just new_linkable)
+ CompOK pcs2 new_details new_iface (Just new_linkable)
+ -> do let hst2 = addToUFM hst1 mod_name new_details
+ hit2 = addToUFM hit1 mod_name new_iface
+ threaded2 = CmThreaded pcs2 hst2 hit2
+
+ return (threaded2, Just new_linkable)
-- Compilation failed. compile may still have updated
-- the PCS, tho.
CompErrs pcs2
- -> let threaded2 = ModThreaded pcs2 hst1 hit1
- in return (False, threaded2, Nothing)
-
+ -> do let threaded2 = CmThreaded pcs2 hst1 hit1
+ return (threaded2, Nothing)
+-- Remove unwanted modules from the top level envs (HST, HIT, UI).
removeFromTopLevelEnvs :: [ModuleName]
-> (HomeSymbolTable, HomeIfaceTable, UnlinkedImage)
-> (HomeSymbolTable, HomeIfaceTable, UnlinkedImage)
filterModuleLinkables (`notElem` zap_these) ui
)
-topological_sort :: [ModSummary] -> [SCC ModSummary]
-topological_sort summaries
+retainInTopLevelEnvs :: [ModuleName]
+ -> (HomeSymbolTable, HomeIfaceTable)
+ -> (HomeSymbolTable, HomeIfaceTable)
+retainInTopLevelEnvs keep_these (hst, hit)
+ = (retainInUFM hst keep_these,
+ retainInUFM hit keep_these
+ )
+ where
+ retainInUFM :: Uniquable key => UniqFM elt -> [key] -> UniqFM elt
+ retainInUFM ufm keys_to_keep
+ = listToUFM (concatMap (maybeLookupUFM ufm) keys_to_keep)
+ maybeLookupUFM ufm u
+ = case lookupUFM ufm u of Nothing -> []; Just val -> [(u, val)]
+
+-- Needed to clean up HIT and HST so that we don't get duplicates in inst env
+downwards_closure_of_module :: [ModSummary] -> ModuleName -> [ModuleName]
+downwards_closure_of_module summaries root
+ = let toEdge :: ModSummary -> (ModuleName,[ModuleName])
+ toEdge summ = (name_of_summary summ, ms_allimps summ)
+ res = simple_transitive_closure (map toEdge summaries) [root]
+ in
+ --trace (showSDoc (text "DC of mod" <+> ppr root
+ -- <+> text "=" <+> ppr res)) (
+ res
+ --)
+
+-- Calculate transitive closures from a set of roots given an adjacency list
+simple_transitive_closure :: Eq a => [(a,[a])] -> [a] -> [a]
+simple_transitive_closure graph set
+ = let set2 = nub (concatMap dsts set ++ set)
+ dsts node = fromMaybe [] (lookup node graph)
+ in
+ if length set == length set2
+ then set
+ else simple_transitive_closure graph set2
+
+
+-- Calculate SCCs of the module graph, with or without taking into
+-- account source imports.
+topological_sort :: Bool -> [ModSummary] -> [SCC ModSummary]
+topological_sort include_source_imports summaries
= let
toEdge :: ModSummary -> (ModSummary,ModuleName,[ModuleName])
toEdge summ
- = (summ, name_of_summary summ, deps_of_summary summ)
-
+ = (summ, name_of_summary summ,
+ (if include_source_imports
+ then ms_srcimps summ else []) ++ ms_imps summ)
+
mash_edge :: (ModSummary,ModuleName,[ModuleName]) -> (ModSummary,Int,[Int])
mash_edge (summ, m, m_imports)
= case lookup m key_map of
in
sccs
--- NB: ignores import-sources for the time being
-downsweep :: ModuleName -- module to chase from
- -> IO [ModSummary]
-downsweep rootNm
- = do rootLoc <- getSummary rootNm
- loop [rootLoc]
+
+-- Chase downwards from the specified root set, returning summaries
+-- for all home modules encountered. Only follow source-import
+-- links. Also returns a Bool to indicate whether any of the roots
+-- are module Main.
+downsweep :: [FilePath] -> [ModSummary] -> IO ([ModSummary], Bool)
+downsweep rootNm old_summaries
+ = do rootSummaries <- mapM getRootSummary rootNm
+ let a_root_is_Main
+ = any ((=="Main").moduleNameUserString.name_of_summary)
+ rootSummaries
+ all_summaries
+ <- loop (concat (map ms_imps rootSummaries))
+ (filter (isHomeModule.ms_mod) rootSummaries)
+ return (all_summaries, a_root_is_Main)
where
+ getRootSummary :: FilePath -> IO ModSummary
+ getRootSummary file
+ | haskellish_file file
+ = do exists <- doesFileExist file
+ if exists then summariseFile file else do
+ throwDyn (OtherError ("can't find file `" ++ file ++ "'"))
+ | otherwise
+ = do exists <- doesFileExist hs_file
+ if exists then summariseFile hs_file else do
+ exists <- doesFileExist lhs_file
+ if exists then summariseFile lhs_file else do
+ getSummary (mkModuleName file)
+ where
+ hs_file = file ++ ".hs"
+ lhs_file = file ++ ".lhs"
+
getSummary :: ModuleName -> IO ModSummary
getSummary nm
- | trace ("getSummary: "++ showSDoc (ppr nm)) True
= do found <- findModule nm
case found of
- Just (mod, location) -> summarise preprocess mod location
+ Just (mod, location) -> do
+ let old_summary = findModInSummaries old_summaries mod
+ new_summary <- summarise mod location old_summary
+ case new_summary of
+ Nothing -> return (fromJust old_summary)
+ Just s -> return s
+
Nothing -> throwDyn (OtherError
- ("no signs of life for module `"
+ ("can't find module `"
++ showSDoc (ppr nm) ++ "'"))
-
- -- loop invariant: homeSummaries doesn't contain package modules
- loop :: [ModSummary] -> IO [ModSummary]
- loop homeSummaries
- = do let allImps :: [ModuleName]
- allImps -- all imports
- = (nub . map mimp_name
- . concat . map ms_get_imports)
- homeSummaries
- let allHome -- all modules currently in homeSummaries
- = map (moduleName.ms_mod) homeSummaries
- let neededImps
- = filter (`notElem` allHome) allImps
- neededSummaries
- <- mapM getSummary neededImps
- let newHomeSummaries
- = filter (isModuleInThisPackage.ms_mod) neededSummaries
- if null newHomeSummaries
- then return homeSummaries
- else loop (newHomeSummaries ++ homeSummaries)
+ -- loop invariant: home_summaries doesn't contain package modules
+ loop :: [ModuleName] -> [ModSummary] -> IO [ModSummary]
+ loop [] home_summaries = return home_summaries
+ loop imps home_summaries
+ = do -- all modules currently in homeSummaries
+ let all_home = map (moduleName.ms_mod) home_summaries
+
+ -- imports for modules we don't already have
+ let needed_imps = nub (filter (`notElem` all_home) imps)
+
+ -- summarise them
+ needed_summaries <- mapM getSummary needed_imps
+
+ -- get just the "home" modules
+ let new_home_summaries
+ = filter (isHomeModule.ms_mod) needed_summaries
+
+ -- loop, checking the new imports
+ let new_imps = concat (map ms_imps new_home_summaries)
+ loop new_imps (new_home_summaries ++ home_summaries)
+
+-----------------------------------------------------------------------------
+-- Summarising modules
+
+-- We have two types of summarisation:
+--
+-- * Summarise a file. This is used for the root module passed to
+-- cmLoadModule. The file is read, and used to determine the root
+-- module name. The module name may differ from the filename.
+--
+-- * Summarise a module. We are given a module name, and must provide
+-- a summary. The finder is used to locate the file in which the module
+-- resides.
+
+summariseFile :: FilePath -> IO ModSummary
+summariseFile file
+ = do hspp_fn <- preprocess file
+ modsrc <- readFile hspp_fn
+
+ let (srcimps,imps,mod_name) = getImports modsrc
+ (path, basename, ext) = splitFilename3 file
+
+ Just (mod, location)
+ <- mkHomeModuleLocn mod_name (path ++ '/':basename) file
+
+ maybe_src_timestamp
+ <- case ml_hs_file location of
+ Nothing -> return Nothing
+ Just src_fn -> maybe_getModificationTime src_fn
+
+ return (ModSummary mod
+ location{ml_hspp_file=Just hspp_fn}
+ srcimps imps
+ maybe_src_timestamp)
+
+-- Summarise a module, and pick up source and timestamp.
+summarise :: Module -> ModuleLocation -> Maybe ModSummary
+ -> IO (Maybe ModSummary)
+summarise mod location old_summary
+ | isHomeModule mod
+ = do let hs_fn = unJust "summarise" (ml_hs_file location)
+
+ maybe_src_timestamp
+ <- case ml_hs_file location of
+ Nothing -> return Nothing
+ Just src_fn -> maybe_getModificationTime src_fn
+
+ -- return the cached summary if the source didn't change
+ case old_summary of {
+ Just s | ms_hs_date s == maybe_src_timestamp -> return Nothing;
+ _ -> do
+
+ hspp_fn <- preprocess hs_fn
+ modsrc <- readFile hspp_fn
+ let (srcimps,imps,mod_name) = getImports modsrc
+
+ maybe_src_timestamp
+ <- case ml_hs_file location of
+ Nothing -> return Nothing
+ Just src_fn -> maybe_getModificationTime src_fn
+
+ when (mod_name /= moduleName mod) $
+ throwDyn (OtherError
+ (showSDoc (text "file name does not match module name: "
+ <+> ppr (moduleName mod) <+> text "vs"
+ <+> ppr mod_name)))
+
+ return (Just (ModSummary mod location{ml_hspp_file=Just hspp_fn}
+ srcimps imps
+ maybe_src_timestamp))
+ }
+
+ | otherwise
+ = return (Just (ModSummary mod location [] [] Nothing))
+
+maybe_getModificationTime :: FilePath -> IO (Maybe ClockTime)
+maybe_getModificationTime fn
+ = (do time <- getModificationTime fn
+ return (Just time))
+ `catch`
+ (\err -> return Nothing)
\end{code}