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Sven Tennie pushed to branch wip/supersven/libDir-setting at Glasgow Haskell Compiler / GHC

Commits:

97b43f2e

by Sven Tennie at 2026-04-15T07:42:39+02:00

Add config setting for LibDir (#19174)

Previously, the libDir was derived from topDir. This won't work for
inplace stage2 cross-compilers where binaries and libraries are in
different stage dirs (`_build/stage1/` for executables and
`_build/stage2` for libraries).

7 changed files:

+ changelog.d/libdir-setting
compiler/GHC/Driver/Config/Interpreter.hs
compiler/GHC/Driver/DynFlags.hs
compiler/GHC/Driver/Session.hs
compiler/GHC/Settings.hs
compiler/GHC/Settings/IO.hs
hadrian/src/Rules/Generate.hs

Changes:

changelog.d/libdir-setting

 +section: packaging
 +synopsis: Added a new configuration setting for ``LibDir`` to support inplace
 +  stage2 cross-compilers where binaries and libraries are in different stage
 +  directories.
 +issues: #19174
 +mrs: !15716
++
 +description: {
 +  Previously, the `libDir` was always derived from `topDir`, which won't work
 +  for inplace stage2 cross-compilers where executables are in `_build/stage1/`
 +  and libraries are in `_build/stage2/`. Now, `LibDir` can be set, but is by
 +  default derived from `topDir`. This facilitates the mentioned behaviour
 +  while leaving the binary distribution code untouched. This is a refactoring
 +  step that does not change actual behaviour.
 +}

compiler/GHC/Driver/Config/Interpreter.hs

@@ -17,8 +17,8 @@ import System.Directory
  initInterpOpts :: DynFlags -> IO InterpOpts
  initInterpOpts dflags = do
 -  wasm_dyld <- makeAbsolute $ topDir dflags </> "dyld.mjs"
 -  js_interp <- makeAbsolute $ topDir dflags </> "ghc-interp.js"
 +  wasm_dyld <- makeAbsolute $ libDir dflags </> "dyld.mjs"
 +  js_interp <- makeAbsolute $ libDir dflags </> "ghc-interp.js"
    pure $ InterpOpts
      { interpExternal = gopt Opt_ExternalInterpreter dflags
      , interpProg = pgm_i dflags

compiler/GHC/Driver/DynFlags.hs

@@ -60,7 +60,7 @@ module GHC.Driver.DynFlags (
          -- ** System tool settings and locations
          programName, projectVersion,
 -        ghcUsagePath, ghciUsagePath, topDir, toolDir,
 +        ghcUsagePath, ghciUsagePath, topDir, libDir, toolDir,
          versionedAppDir, versionedFilePath,
          extraGccViaCFlags, globalPackageDatabasePath,
@@ -1508,6 +1508,8 @@ ghciUsagePath         :: DynFlags -> FilePath
  ghciUsagePath dflags = fileSettings_ghciUsagePath $ fileSettings dflags
  topDir                :: DynFlags -> FilePath
  topDir dflags = fileSettings_topDir $ fileSettings dflags
 +libDir                :: DynFlags -> FilePath
 +libDir dflags = fileSettings_libDir $ fileSettings dflags
  toolDir               :: DynFlags -> Maybe FilePath
  toolDir dflags = fileSettings_toolDir $ fileSettings dflags
  extraGccViaCFlags     :: DynFlags -> [String]

compiler/GHC/Driver/Session.hs

@@ -3548,9 +3548,9 @@ compilerInfo dflags
        ("Project name",                 cProjectName)
        -- Next come the settings, so anything else can be overridden
        -- in the settings file (as "lookup" uses the first match for the
 -      -- key)
 +      -- key). We filter out LibDir from rawSettings to avoid duplication.
       : map (fmap expandDirectories)
 -           (rawSettings dflags)
 +           (filter ((/= "LibDir") . fst) (rawSettings dflags))
       ++
        [("C compiler command", queryCmd $ ccProgram . tgtCCompiler),
         ("C compiler flags", queryFlags $ ccProgram . tgtCCompiler),
@@ -3651,7 +3651,7 @@ compilerInfo dflags
         -- Whether or not GHC was compiled using -prof
         ("GHC Profiled",                showBool hostIsProfiled),
         ("Debug on",                    showBool debugIsOn),
 -       ("LibDir",                      topDir dflags),
 +       ("LibDir",                      libDir dflags),
         -- This is always an absolute path, unlike "Relative Global Package DB" which is
         -- in the settings file.
         ("Global Package DB",           globalPackageDatabasePath dflags)

compiler/GHC/Settings.hs

@@ -184,6 +184,7 @@ data FileSettings = FileSettings
    , fileSettings_toolDir               :: Maybe FilePath -- ditto
    , fileSettings_topDir                :: FilePath       -- ditto
    , fileSettings_globalPackageDatabase :: FilePath
 +  , fileSettings_libDir                :: FilePath
+   }

compiler/GHC/Settings/IO.hs

@@ -28,6 +28,7 @@ import GHC.Toolchain.Program
  import GHC.Toolchain
  import GHC.Data.Maybe
  import Data.Bifunctor (Bifunctor(second))
 +import Data.Either (fromRight)
  data SettingsError
    = SettingsError_MissingData String
@@ -148,6 +149,13 @@ initSettings top_dir = do
    baseUnitId <- getSetting_raw "base unit-id"
 +  -- LibDir is optional. If not set, derive it from topDir. This allows
 +  -- bindists to work without explicitly setting LibDir, but gives us the
 +  -- option to override it for inplace test compilers (the "stage2
 +  -- cross-compiler" scenario).
 +  let lib_dir = fromRight top_dir $
 +                  getRawFilePathSetting top_dir settingsFile mySettings "LibDir"
++
    return $ Settings
      { sGhcNameVersion = GhcNameVersion
        { ghcNameVersion_programName = "ghc"
@@ -159,6 +167,7 @@ initSettings top_dir = do
        , fileSettings_ghciUsagePath  = ghci_usage_msg_path
        , fileSettings_toolDir        = mtool_dir
        , fileSettings_topDir         = top_dir
 +      , fileSettings_libDir         = lib_dir
        , fileSettings_globalPackageDatabase = globalpkgdb_path
+       }

hadrian/src/Rules/Generate.hs

@@ -25,6 +25,7 @@ import Utilities
  import GHC.Toolchain as Toolchain hiding (HsCpp(HsCpp))
  import GHC.Platform.ArchOS
  import Settings.Program (ghcWithInterpreter)
 +import Hadrian.Oracles.Path
  -- | Track this file to rebuild generated files whenever it changes.
  trackGenerateHs :: Expr ()
@@ -481,6 +482,16 @@ generateSettings settingsFile = do
          Stage3 -> pkgUnitId Stage2 base
      let rel_pkg_db = makeRelativeNoSysLink (dropFileName settingsFile) package_db_path
 +        make_absolute rel_path = do
 +          abs_path <- liftIO (makeAbsolute rel_path)
 +          fixAbsolutePathOnWindows abs_path
++
 +        -- E.g. the Stage2 compiler lives in _build/stage1
 +        -- So, we need to decrement the stage to get the correct directory
 +        stage_dir_stage = predStage stage
++
 +    rel_lib_topDir :: FilePath <- expr $ stageLibPath stage_dir_stage
 +    lib_topDir :: FilePath <- expr $ make_absolute rel_lib_topDir
      settings <- traverse sequence $
          [ ("unlit command", ("$topdir/../bin/" <>) <$> expr (programName (ctx { Context.package = unlit })))
@@ -488,6 +499,7 @@ generateSettings settingsFile = do
          , ("RTS ways", escapeArgs . map show . Set.toList <$> getRtsWays)
          , ("Relative Global Package DB", pure rel_pkg_db)
          , ("base unit-id", pure base_unit_id)
 +        , ("LibDir", pure lib_topDir)
+         ]
      let showTuple (k, v) = "(" ++ show k ++ ", " ++ show v ++ ")"
      pure $ case settings of