[Git][ghc/ghc][master] hi: Deterministic ImportedMods in Usages

Marge Bot (@marge-bot) gitlab at gitlab.haskell.org
Tue Aug 6 01:03:29 UTC 2024



Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC


Commits:
a1e42e7a by Rodrigo Mesquita at 2024-08-05T21:03:04-04:00
hi: Deterministic ImportedMods in Usages

The `mi_usages` field of the interface files must use a deterministic
list of `Usage`s to guarantee a deterministic interface. However, this
list was, in its origins, constructed from a `ModuleEnv` which uses a
non-deterministic ordering that was leaking into the interface.

Specifically, ImportedMods = ModuleEnv ... would get converted to a list and
then passed to `mkUsageInfo` to construct the Usages.

The solution is simple. Back `ImportedMods` with a deterministic map.
`Map Module ...` is enough, since the Ord instance for `Module` already
uses a stable, deterministic, comparison.

Fixes #25131

- - - - -


11 changed files:

- compiler/GHC/Driver/Main.hs
- compiler/GHC/HsToCore/Docs.hs
- compiler/GHC/HsToCore/Usage.hs
- compiler/GHC/Rename/Names.hs
- compiler/GHC/Rename/Unbound.hs
- compiler/GHC/Tc/Gen/Export.hs
- compiler/GHC/Tc/Gen/Splice.hs
- compiler/GHC/Tc/Module.hs
- compiler/GHC/Tc/Types.hs
- compiler/GHC/Unit/Module/Imported.hs
- compiler/GHC/Unit/Module/ModIface.hs


Changes:

=====================================
compiler/GHC/Driver/Main.hs
=====================================
@@ -1489,7 +1489,7 @@ checkSafeImports tcg_env
   where
     impInfo  = tcg_imports tcg_env     -- ImportAvails
     imports  = imp_mods impInfo        -- ImportedMods
-    imports1 = moduleEnvToList imports -- (Module, [ImportedBy])
+    imports1 = M.toList imports -- (Module, [ImportedBy])
     imports' = map (fmap importedByUser) imports1 -- (Module, [ImportedModsVal])
     pkgReqs  = imp_trust_pkgs impInfo  -- [Unit]
 


=====================================
compiler/GHC/HsToCore/Docs.hs
=====================================
@@ -34,7 +34,6 @@ import GHC.IORef (readIORef)
 import GHC.Unit.Types
 import GHC.Hs
 import GHC.Types.Avail
-import GHC.Unit.Module
 import qualified Data.List.NonEmpty as NonEmpty
 import Data.List.NonEmpty (NonEmpty ((:|)))
 import GHC.Unit.Module.Imported
@@ -183,13 +182,12 @@ mkDocStructureFromExportList mdl import_avails export_list =
     aliasMap =
         M.fromListWith (<>) $
           (this_mdl_name, this_mdl_name :| [])
-          : (flip concatMap (moduleEnvToList imported) $ \(mdl, imvs) ->
+          : (flip concatMap (M.toList imported) $ \(mdl, imvs) ->
               [(imv_name imv, moduleName mdl :| []) | imv <- imvs])
       where
         this_mdl_name = moduleName mdl
 
-    imported :: ModuleEnv [ImportedModsVal]
-    imported = mapModuleEnv importedByUser (imp_mods import_avails)
+    imported = M.map importedByUser (imp_mods import_avails)
 
 -- | Figure out the documentation structure by correlating
 -- the module exports with the located declarations.


=====================================
compiler/GHC/HsToCore/Usage.hs
=====================================
@@ -208,7 +208,7 @@ mk_mod_usage_info uc home_unit home_unit_ids this_mod direct_imports used_names
     safe_implicit_imps_req = uc_safe_implicit_imps_req uc
 
     used_mods    = moduleEnvKeys ent_map
-    dir_imp_mods = moduleEnvKeys direct_imports
+    dir_imp_mods = Map.keys direct_imports
     all_mods     = used_mods ++ filter (`notElem` used_mods) dir_imp_mods
     usage_mods   = sortBy stableModuleCmp all_mods
                         -- canonical order is imported, to avoid interface-file
@@ -289,7 +289,7 @@ mk_mod_usage_info uc home_unit home_unit_ids this_mod direct_imports used_names
         by_is_safe (ImportedByUser imv) = imv_is_safe imv
         by_is_safe _ = False
         (is_direct_import, imp_safe)
-            = case lookupModuleEnv direct_imports mod of
+            = case Map.lookup mod direct_imports of
                 -- ezyang: I'm not sure if any is the correct
                 -- metric here. If safety was guaranteed to be uniform
                 -- across all imports, why did the old code only look


=====================================
compiler/GHC/Rename/Names.hs
=====================================
@@ -573,7 +573,7 @@ calculateAvails home_unit other_home_units iface mod_safe' want_boot imported_by
 
 
   in ImportAvails {
-          imp_mods       = unitModuleEnv (mi_module iface) [imported_by],
+          imp_mods       = Map.singleton (mi_module iface) [imported_by],
           imp_orphs      = orphans,
           imp_finsts     = finsts,
           imp_sig_mods   = sig_mods,


=====================================
compiler/GHC/Rename/Unbound.hs
=====================================
@@ -66,6 +66,7 @@ import Data.List (sortBy, partition, nub)
 import Data.List.NonEmpty ( pattern (:|), NonEmpty )
 import Data.Function ( on )
 import qualified Data.Semigroup as S
+import qualified Data.Map as M
 
 {-
 ************************************************************************
@@ -339,7 +340,7 @@ importSuggestions looking_for global_env hpt currMod imports rdr_name
   -- What import statements provide "Mod" at all
   -- or, if this is an unqualified name, are not qualified imports
   interesting_imports = [ (mod, imp)
-    | (mod, mod_imports) <- moduleEnvToList (imp_mods imports)
+    | (mod, mod_imports) <- M.toList (imp_mods imports)
     , Just imp <- return $ pick (importedByUser mod_imports)
     ]
 


=====================================
compiler/GHC/Tc/Gen/Export.hs
=====================================
@@ -52,6 +52,7 @@ import Control.Monad ( when )
 import qualified Data.List.NonEmpty as NE
 import Data.Traversable   ( for )
 import Data.List ( sortBy )
+import qualified Data.Map as Map
 
 {-
 ************************************************************************
@@ -307,7 +308,7 @@ exports_from_avail (Just (L _ rdr_items)) rdr_env imports this_mod
       = [gre]
 
     imported_modules = [ imv_name imv
-                       | xs <- moduleEnvElts $ imp_mods imports
+                       | xs <- Map.elems $ imp_mods imports
                        , imv <- importedByUser xs ]
 
     exports_from_item :: ExportAccum -> LIE GhcPs


=====================================
compiler/GHC/Tc/Gen/Splice.hs
=====================================
@@ -2886,7 +2886,7 @@ reifyModule (TH.Module (TH.PkgName pkgString) (TH.ModName mString)) = do
   if (reifMod == this_mod) then reifyThisModule else reifyFromIface reifMod
     where
       reifyThisModule = do
-        usages <- fmap (map modToTHMod . moduleEnvKeys . imp_mods) getImports
+        usages <- fmap (map modToTHMod . Map.keys . imp_mods) getImports
         return $ TH.ModuleInfo usages
 
       reifyFromIface reifMod = do


=====================================
compiler/GHC/Tc/Module.hs
=====================================
@@ -178,6 +178,7 @@ import Data.List.NonEmpty ( NonEmpty (..) )
 import qualified Data.List.NonEmpty as NE
 import Data.Ord
 import qualified Data.Set as S
+import qualified Data.Map as M
 import Data.Foldable ( for_ )
 import Data.Traversable ( for )
 
@@ -432,7 +433,7 @@ tcRnImports hsc_env import_decls
                 -- Check type-family consistency between imports.
                 -- See Note [The type family instance consistency story]
         ; traceRn "rn1: checking family instance consistency {" empty
-        ; let { dir_imp_mods = moduleEnvKeys
+        ; let { dir_imp_mods = M.keys
                              . imp_mods
                              $ imports }
         ; checkFamInstConsistency dir_imp_mods


=====================================
compiler/GHC/Tc/Types.hs
=====================================
@@ -176,6 +176,7 @@ import GHCi.RemoteTypes
 
 import Data.Set      ( Set )
 import qualified Data.Set as S
+import qualified Data.Map as M
 import Data.Dynamic  ( Dynamic )
 import Data.Map ( Map )
 import Data.Typeable ( TypeRep )
@@ -916,7 +917,7 @@ plusModDeps = plusInstalledModuleEnv plus_mod_dep
       -- perf/compiler/MultiLayerModules
 
 emptyImportAvails :: ImportAvails
-emptyImportAvails = ImportAvails { imp_mods          = emptyModuleEnv,
+emptyImportAvails = ImportAvails { imp_mods          = M.empty,
                                    imp_direct_dep_mods = emptyInstalledModuleEnv,
                                    imp_dep_direct_pkgs = S.empty,
                                    imp_sig_mods      = [],
@@ -947,7 +948,7 @@ plusImportAvails
                   imp_sig_mods = sig_mods2,
                   imp_trust_pkgs = tpkgs2, imp_trust_own_pkg = tself2,
                   imp_orphs = orphs2, imp_finsts = finsts2 })
-  = ImportAvails { imp_mods          = plusModuleEnv_C (++) mods1 mods2,
+  = ImportAvails { imp_mods          = M.unionWith (++) mods1 mods2,
                    imp_direct_dep_mods = ddmods1 `plusModDeps` ddmods2,
                    imp_dep_direct_pkgs      = ddpkgs1 `S.union` ddpkgs2,
                    imp_trust_pkgs    = tpkgs1 `S.union` tpkgs2,


=====================================
compiler/GHC/Unit/Module/Imported.hs
=====================================
@@ -13,10 +13,13 @@ import GHC.Unit.Module
 import GHC.Types.Name.Reader
 import GHC.Types.SafeHaskell
 import GHC.Types.SrcLoc
+import Data.Map (Map)
 
 -- | Records the modules directly imported by a module for extracting e.g.
 -- usage information, and also to give better error message
-type ImportedMods = ModuleEnv [ImportedBy]
+type ImportedMods = Map Module [ImportedBy]
+  -- We don't want to use a `ModuleEnv` since it would leak a non-deterministic
+  -- order to the interface files when passed as a list to `mkUsageInfo`.
 
 -- | If a module was "imported" by the user, we associate it with
 -- more detailed usage information 'ImportedModsVal'; a module


=====================================
compiler/GHC/Unit/Module/ModIface.hs
=====================================
@@ -245,6 +245,9 @@ data ModIface_ (phase :: ModIfacePhase)
                 -- doesn't affect the hash of this module)
                 -- NOT STRICT!  we read this field lazily from the interface file
                 -- It is *only* consulted by the recompilation checker
+                --
+                -- The elements must be *deterministically* sorted to guarantee
+                -- deterministic interface files
 
         mi_exports_  :: ![IfaceExport],
                 -- ^ Exports



View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/a1e42e7ac6121404afb2a42e11d0c778ce0fe483

-- 
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/a1e42e7ac6121404afb2a42e11d0c778ce0fe483
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