FinderCache: Also cache file hashing in interface file checkswip/hash-file-cache

Now that we hash object files to decide when to recompile due to TH,
this can make a big difference as each interface file in a project will
contain reference to the object files of all package dependencies.
Especially when these are statically linked, hashing them can add up.

The cache is invalidated when `depanalPartial` is called, like the
normal finder cache.

1 files changed, 6 insertions, 1 deletions

diff --git a/compiler/GHC/Unit/Finder/Types.hs b/compiler/GHC/Unit/Finder/Types.hs
index 06f4ea8aae..c48b7d9789 100644
--- a/compiler/GHC/Unit/Finder/Types.hs
+++ b/compiler/GHC/Unit/Finder/Types.hs
@@ -9,6 +9,8 @@ where
 import GHC.Prelude
 import GHC.Unit
 import GHC.Unit.State
+import qualified Data.Map as M
+import GHC.Fingerprint
 
 import Data.IORef
 
@@ -18,7 +20,10 @@ import Data.IORef
 -- contents of this cache.
 --
 type FinderCacheState = InstalledModuleEnv InstalledFindResult
-newtype FinderCache = FinderCache (IORef FinderCacheState)
+type FileCacheState   = M.Map FilePath Fingerprint
+data FinderCache = FinderCache { fcModuleCache :: (IORef FinderCacheState)
+                               , fcFileCache   :: (IORef FileCacheState)
+                               }
 
 data InstalledFindResult
   = InstalledFound ModLocation InstalledModule