Commit 16ba7571 authored by Simon Marlow's avatar Simon Marlow Committed by ian@well-typed.com

Invalidate the ModSummary cache in setSessionDynFlags (#7478)

parent 723570da
......@@ -498,6 +498,7 @@ setSessionDynFlags dflags = do
(dflags', preload) <- liftIO $ initPackages dflags
modifySession $ \h -> h{ hsc_dflags = dflags'
, hsc_IC = (hsc_IC h){ ic_dflags = dflags' } }
invalidateModSummaryCache
return preload
-- | Sets the program 'DynFlags'.
......@@ -505,8 +506,34 @@ setProgramDynFlags :: GhcMonad m => DynFlags -> m [PackageId]
setProgramDynFlags dflags = do
(dflags', preload) <- liftIO $ initPackages dflags
modifySession $ \h -> h{ hsc_dflags = dflags' }
invalidateModSummaryCache
return preload
-- When changing the DynFlags, we want the changes to apply to future
-- loads, but without completely discarding the program. But the
-- DynFlags are cached in each ModSummary in the hsc_mod_graph, so
-- after a change to DynFlags, the changes would apply to new modules
-- but not existing modules; this seems undesirable.
--
-- Furthermore, the GHC API client might expect that changing
-- log_action would affect future compilation messages, but for those
-- modules we have cached ModSummaries for, we'll continue to use the
-- old log_action. This is definitely wrong (#7478).
--
-- Hence, we invalidate the ModSummary cache after changing the
-- DynFlags. We do this by tweaking the date on each ModSummary, so
-- that the next downsweep will think that all the files have changed
-- and preprocess them again. This won't necessarily cause everything
-- to be recompiled, because by the time we check whether we need to
-- recopmile a module, we'll have re-summarised the module and have a
-- correct ModSummary.
--
invalidateModSummaryCache :: GhcMonad m => m ()
invalidateModSummaryCache =
modifySession $ \h -> h { hsc_mod_graph = map inval (hsc_mod_graph h) }
where
inval ms = ms { ms_hs_date = addUTCTime (-1) (ms_hs_date ms) }
-- | Returns the program 'DynFlags'.
getProgramDynFlags :: GhcMonad m => m DynFlags
getProgramDynFlags = getSessionDynFlags
......
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