1 files changed, 61 insertions, 0 deletions
diff --git a/compiler/GHC/Unit/Env.hs b/compiler/GHC/Unit/Env.hs
new file mode 100644
index 0000000000..d7de796434
--- /dev/null
+++ b/compiler/GHC/Unit/Env.hs
@@ -0,0 +1,61 @@
+module GHC.Unit.Env
+    ( UnitEnv (..)
+    , preloadUnitsInfo
+    , preloadUnitsInfo'
+    )
+where
+
+import GHC.Prelude
+
+import GHC.Unit.State
+import GHC.Unit.Home
+import GHC.Unit.Types
+
+import GHC.Platform
+import GHC.Settings
+import GHC.Data.Maybe
+
+data UnitEnv = UnitEnv
+    { ue_units     :: !UnitState      -- ^ Units
+    , ue_home_unit :: !HomeUnit       -- ^ Home unit
+    , ue_platform  :: !Platform       -- ^ Platform
+    , ue_namever   :: !GhcNameVersion -- ^ GHC name/version (used for dynamic library suffix)
+    }
+
+-- -----------------------------------------------------------------------------
+-- Extracting information from the packages in scope
+
+-- Many of these functions take a list of packages: in those cases,
+-- the list is expected to contain the "dependent packages",
+-- i.e. those packages that were found to be depended on by the
+-- current module/program.  These can be auto or non-auto packages, it
+-- doesn't really matter.  The list is always combined with the list
+-- of preload (command-line) packages to determine which packages to
+-- use.
+
+-- | Lookup 'UnitInfo' for every preload unit from the UnitState, for every unit
+-- used to instantiate the home unit, and for every unit explicitly passed in
+-- the given list of UnitId.
+preloadUnitsInfo' :: UnitEnv -> [UnitId] -> MaybeErr UnitErr [UnitInfo]
+preloadUnitsInfo' unit_env ids0 = all_infos
+  where
+    home_unit  = ue_home_unit unit_env
+    unit_state = ue_units     unit_env
+    ids      = ids0 ++ inst_ids
+    inst_ids
+       -- An indefinite package will have insts to HOLE,
+       -- which is not a real package. Don't look it up.
+       -- Fixes #14525
+       | isHomeUnitIndefinite home_unit = []
+       | otherwise = map (toUnitId . moduleUnit . snd) (homeUnitInstantiations home_unit)
+    pkg_map = unitInfoMap unit_state
+    preload = preloadUnits unit_state
+
+    all_pkgs  = closeUnitDeps' pkg_map preload (ids `zip` repeat Nothing)
+    all_infos = map (unsafeLookupUnitId unit_state) <$> all_pkgs
+
+
+-- | Lookup 'UnitInfo' for every preload unit from the UnitState and for every
+-- unit used to instantiate the home unit.
+preloadUnitsInfo :: UnitEnv -> MaybeErr UnitErr [UnitInfo]
+preloadUnitsInfo unit_env = preloadUnitsInfo' unit_env []