[project @ 2002-03-27 16:48:47 by simonmar]

Sigh, recompilation checking in --make mdoe has been badly broken for
well, probably ever.

The problem is that in GHCi mode there's a restriction on the use of
object files, namely that an object file may only depend on other
up-to-date object files in order to be up-to-date itself, because we
don't have support for linking object code to interpreted code.
Unfortunately we were applying this restriction to --make compilations
too, with the result that far too much recompilation was happening.

MERGE TO STABLE

diff --git a/ghc/compiler/compMan/CompManager.lhs b/ghc/compiler/compMan/CompManager.lhs
index dea4136..1e5fdd6 100644 (file)
--- a/ghc/compiler/compMan/CompManager.lhs
+++ b/ghc/compiler/compMan/CompManager.lhs
@@ -541,7 +541,8 @@ cmLoadModules cmstate1 dflags mg2unsorted
        -- Sort out which linkables we wish to keep in the unlinked image.
        -- See getValidLinkables below for details.
        (valid_old_linkables, new_linkables)
-           <- getValidLinkables ui1 mg2unsorted_names mg2_with_srcimps
+           <- getValidLinkables ghci_mode ui1 
+                 mg2unsorted_names mg2_with_srcimps
 
        -- putStrLn (showSDoc (vcat [ppr valid_old_linkables, ppr new_linkables]))
 
@@ -717,7 +718,7 @@ ppFilesFromSummaries summaries
 
 
 -----------------------------------------------------------------------------
--- getValidLin
+-- getValidLinkables
 
 -- For each module (or SCC of modules), we take:
 --
@@ -726,9 +727,11 @@ ppFilesFromSummaries summaries
 --
 --     - the old linkable, otherwise (and if one is available).
 --
--- and we throw away the linkable if it is older than the source
--- file.  We ignore the on-disk linkables unless all of the dependents
--- of this SCC also have on-disk linkables.
+-- and we throw away the linkable if it is older than the source file.
+-- In interactive mode, we also ignore the on-disk linkables unless
+-- all of the dependents of this SCC also have on-disk linkables (we
+-- can't have dynamically loaded objects that depend on interpreted
+-- modules in GHCi).
 --
 -- 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
@@ -737,15 +740,16 @@ ppFilesFromSummaries summaries
 -- ToDo: this pass could be merged with the preUpsweep.
 
 getValidLinkables
-       :: [Linkable]           -- old linkables
+       :: GhciMode
+       -> [Linkable]           -- old linkables
        -> [ModuleName]         -- all home modules
        -> [SCC ModSummary]     -- all modules in the program, dependency order
        -> IO ( [Linkable],     -- still-valid linkables 
                [Linkable]      -- new linkables we just found
              )
 
-getValidLinkables old_linkables all_home_mods module_graph = do
-  ls <- foldM (getValidLinkablesSCC old_linkables all_home_mods) 
+getValidLinkables mode old_linkables all_home_mods module_graph = do
+  ls <- foldM (getValidLinkablesSCC mode old_linkables all_home_mods) 
                [] module_graph
   return (partition_it ls [] [])
  where
@@ -755,7 +759,7 @@ getValidLinkables old_linkables all_home_mods module_graph = do
        | otherwise = partition_it ls (l:valid) new
 
 
-getValidLinkablesSCC old_linkables all_home_mods new_linkables scc0
+getValidLinkablesSCC mode old_linkables all_home_mods new_linkables scc0
    = let 
          scc             = flattenSCC scc0
           scc_names       = map modSummaryName scc
@@ -770,7 +774,7 @@ getValidLinkablesSCC old_linkables all_home_mods new_linkables scc0
                    Nothing -> False
                    Just l  -> isObjectLinkable l
 
-          objects_allowed = all has_object scc_allhomeimps
+          objects_allowed = mode == Batch || all has_object scc_allhomeimps
      in do
 
      new_linkables'