driver: Cleanups related to ModLocation

ModLocation is the data type which tells you the locations of all the
build products which can affect recompilation. It is now computed in one
place and not modified through the pipeline. Important locations will
now just consult ModLocation rather than construct the dynamic object
path incorrectly.

* Add paths for dynamic object and dynamic interface files to
  ModLocation.
* Always use the paths from mod location when looking for where to find
  any interface or object file.
* Always use the paths in a ModLocation when deciding where to write an
  interface and object file.
* Remove `dynamicOutputFile` and `dynamicOutputHi` functions which
  *calculated* (incorrectly) the location of `dyn_o` and `dyn_hi` files.
* Don't set `outputFile_` and so-on in `enableCodeGenWhen`, `-o` and
  hence `outputFile_` should not affect the location of object files in
  `--make` mode. It is now sufficient to just update the ModLocation with
  the temporary paths.
* In `hscGenBackendPipeline` don't recompute the `ModLocation` to
  account for `-dynamic-too`, the paths are now accurate from the start
  of the run.
* Rename `getLocation` to `mkOneShotModLocation`, as that's the only
  place it's used. Increase the locality of the definition by moving it
  close to the use-site.
* Load the dynamic interface from ml_dyn_hi_file rather than attempting
  to reconstruct it in load_dynamic_too.
* Add a variety of tests to check how -o -dyno etc interact with each
  other.

Some other clean-ups

* DeIOify mkHomeModLocation and friends, they are all pure functions.
* Move FinderOpts into GHC.Driver.Config.Finder, next to initFinderOpts.
* Be more precise about whether we mean outputFile or outputFile_: there
  were many places where outputFile was used but the result shouldn't have
  been affected by `-dyno` (for example the filename of the resulting
  executable). In these places dynamicNow would never be set but it's
  still more precise to not allow for this possibility.
* Typo fixes suffices -> suffixes in the appropiate places.

1 files changed, 10 insertions, 10 deletions

diff --git a/compiler/GHC/Iface/Load.hs b/compiler/GHC/Iface/Load.hs
index 2b31074896..64df715755 100644
--- a/compiler/GHC/Iface/Load.hs
+++ b/compiler/GHC/Iface/Load.hs
@@ -912,10 +912,10 @@ findAndReadIface logger name_cache fc hooks unit_state home_unit dflags doc_str
                         case r of
                           Failed _
                             -> return ()
-                          Succeeded (iface,fp)
+                          Succeeded (iface,_fp)
                             -> load_dynamic_too_maybe logger name_cache unit_state
                                                       dflags wanted_mod
-                                                      hi_boot_file iface fp
+                                                      hi_boot_file iface loc
                         return r
               err -> do
                   trace_if logger (text "...not found")
@@ -928,20 +928,20 @@ findAndReadIface logger name_cache fc hooks unit_state home_unit dflags doc_str
                                       err
 
 -- | Check if we need to try the dynamic interface for -dynamic-too
-load_dynamic_too_maybe :: Logger -> NameCache -> UnitState -> DynFlags -> Module -> IsBootInterface -> ModIface -> FilePath -> IO ()
-load_dynamic_too_maybe logger name_cache unit_state dflags wanted_mod is_boot iface file_path
+load_dynamic_too_maybe :: Logger -> NameCache -> UnitState -> DynFlags -> Module -> IsBootInterface -> ModIface -> ModLocation -> IO ()
+load_dynamic_too_maybe logger name_cache unit_state dflags wanted_mod is_boot iface loc
   -- Indefinite interfaces are ALWAYS non-dynamic.
   | not (moduleIsDefinite (mi_module iface)) = return ()
   | otherwise = dynamicTooState dflags  >>= \case
       DT_Dont   -> return ()
       DT_Failed -> return ()
-      DT_Dyn    -> load_dynamic_too logger name_cache unit_state dflags wanted_mod is_boot iface file_path
-      DT_OK     -> load_dynamic_too logger name_cache unit_state (setDynamicNow dflags) wanted_mod is_boot iface file_path
+      DT_Dyn    -> load_dynamic_too logger name_cache unit_state dflags wanted_mod iface file_path
+      DT_OK     -> load_dynamic_too logger name_cache unit_state (setDynamicNow dflags) wanted_mod iface file_path
+  where
+    file_path = addBootSuffix_maybe is_boot (ml_dyn_hi_file loc)
 
-load_dynamic_too :: Logger -> NameCache -> UnitState -> DynFlags -> Module -> IsBootInterface -> ModIface -> FilePath -> IO ()
-load_dynamic_too logger name_cache unit_state dflags wanted_mod is_boot iface file_path = do
-  let dynFilePath = addBootSuffix_maybe is_boot
-                  $ replaceExtension file_path (hiSuf dflags)
+load_dynamic_too :: Logger -> NameCache -> UnitState -> DynFlags -> Module -> ModIface -> FilePath -> IO ()
+load_dynamic_too logger name_cache unit_state dflags wanted_mod iface dynFilePath = do
   read_file logger name_cache unit_state dflags wanted_mod dynFilePath >>= \case
     Succeeded (dynIface, _)
      | mi_mod_hash (mi_final_exts iface) == mi_mod_hash (mi_final_exts dynIface)