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Diffstat (limited to 'compiler/GHC/Unit/State.hs')
| -rw-r--r-- | compiler/GHC/Unit/State.hs | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/compiler/GHC/Unit/State.hs b/compiler/GHC/Unit/State.hs index 55855da61f..e178bafea6 100644 --- a/compiler/GHC/Unit/State.hs +++ b/compiler/GHC/Unit/State.hs @@ -31,6 +31,7 @@ module GHC.Unit.State ( unsafeLookupUnitId, lookupPackageName, + resolvePackageImport, improveUnit, searchPackageId, listVisibleModuleNames, @@ -534,6 +535,8 @@ unsafeLookupUnitId state uid = case lookupUnitId state uid of -- | Find the unit we know about with the given package name (e.g. @foo@), if any -- (NB: there might be a locally defined unit name which overrides this) +-- This function is unsafe to use in general because it doesn't respect package +-- visibility. lookupPackageName :: UnitState -> PackageName -> Maybe UnitId lookupPackageName pkgstate n = lookupUFM (packageNameMap pkgstate) n @@ -542,6 +545,21 @@ searchPackageId :: UnitState -> PackageId -> [UnitInfo] searchPackageId pkgstate pid = filter ((pid ==) . unitPackageId) (listUnitInfo pkgstate) +-- | Find the UnitId which an import qualified by a package import comes from. +-- Compared to 'lookupPackageName', this function correctly accounts for visibility, +-- renaming and thinning. +resolvePackageImport :: UnitState -> ModuleName -> PackageName -> Maybe UnitId +resolvePackageImport unit_st mn pn = do + -- 1. Find all modules providing the ModuleName (this accounts for visibility/thinning etc) + providers <- Map.lookup mn (moduleNameProvidersMap unit_st) + -- 2. Get the UnitIds of the candidates + let candidates_uid = map (toUnitId . moduleUnit) $ Map.keys providers + -- 3. Get the package names of the candidates + let candidates_units = map (\ui -> ((unitPackageName ui), unitId ui)) + $ mapMaybe (\uid -> Map.lookup uid (unitInfoMap unit_st)) candidates_uid + -- 4. Check to see if the PackageName helps us disambiguate any candidates. + lookup pn candidates_units + -- | Create a Map UnitId UnitInfo -- -- For each instantiated unit, we add two map keys: |