Sven Tennie pushed to branch wip/supersven/libDir-setting at Glasgow Haskell Compiler / GHC Commits: a80ad47e by Sven Tennie at 2026-05-10T10:50:37+02:00 Make global package DB path relative to libDir/LibDir (#19174) The global package db is part of the `lib/` folder. If we want to point for inplace cross-compilers to the succeeding stage's folder, this is done by setting LibDir. Thus, the global package db must be found relative to libDir (which may default to topDir) or LibDir if it's set. - - - - - 86b50b9d by Sven Tennie at 2026-05-10T10:50:37+02:00 Add Haddock to FileSettings Helping to understand the fields' meanings without deeper analyses. - - - - - 34ab680e by Sven Tennie at 2026-05-10T10:50:37+02:00 Test LibDir setting The complexity of settings becomes scary. Add a test to ensure LibDir works as expected. - - - - - 8 changed files: - compiler/GHC/Settings.hs - compiler/GHC/Settings/IO.hs - hadrian/src/Rules/BinaryDist.hs - hadrian/src/Rules/Generate.hs - libraries/ghc-boot/GHC/Settings/Utils.hs - + testsuite/tests/ghc-api/settings/LibDir.hs - + testsuite/tests/ghc-api/settings/LibDir.stdout - + testsuite/tests/ghc-api/settings/all.T Changes: ===================================== compiler/GHC/Settings.hs ===================================== @@ -179,12 +179,24 @@ data ToolSettings = ToolSettings -- | Paths to various files and directories used by GHC, including those that -- provide more settings. data FileSettings = FileSettings - { fileSettings_ghcUsagePath :: FilePath -- ditto - , fileSettings_ghciUsagePath :: FilePath -- ditto - , fileSettings_toolDir :: Maybe FilePath -- ditto - , fileSettings_topDir :: FilePath -- ditto + { fileSettings_ghcUsagePath :: FilePath + -- ^ Path to @ghc-usage.txt@, displayed by @ghc --help@ + , fileSettings_ghciUsagePath :: FilePath + -- ^ Path to @ghci-usage.txt@, displayed by @ghci --help@ + , fileSettings_toolDir :: Maybe FilePath + -- ^ Directory containing the mingw toolchain (Windows only); + -- see Note [tooldir: How GHC finds mingw on Windows] in `GHC.SysTools.BaseDir` + , fileSettings_topDir :: FilePath + -- ^ GHC's top directory: the root from which GHC locates its support files + -- (e.g. settings). + -- See Note [topdir: How GHC finds its files] in `GHC.SysTools.BaseDir` , fileSettings_globalPackageDatabase :: FilePath + -- ^ Path to the global package database , fileSettings_libDir :: FilePath + -- ^ Directory containing GHC's library packages and the global package + -- database. Defaults to 'fileSettings_topDir' but can differ in inplace + -- builds used for cross-compilation testing (the "stage2 cross-compiler" + -- scenario). } ===================================== compiler/GHC/Settings/IO.hs ===================================== @@ -118,12 +118,6 @@ initSettings top_dir = do then ["-fwrapv", "-fno-builtin"] else [] - -- The package database is either a relative path to the location of the settings file - -- OR an absolute path. - -- In case the path is absolute then top_dir </> abs_path == abs_path - -- the path is relative then top_dir </> rel_path == top_dir </> rel_path - globalpkgdb_path <- installed <$> getSetting "Relative Global Package DB" - let ghc_usage_msg_path = installed "ghc-usage.txt" ghci_usage_msg_path = installed "ghci-usage.txt" @@ -157,6 +151,11 @@ initSettings top_dir = do let lib_dir = installed $ fromRight "." $ getRawFilePathSetting top_dir settingsFile mySettings "LibDir" + -- The package database is either a relative path to lib_dir OR an absolute path. + -- In case the path is absolute then lib_dir </> abs_path == abs_path + -- the path is relative then lib_dir </> rel_path == lib_dir </> rel_path + globalpkgdb_path <- (lib_dir </>) <$> getSetting "Relative Global Package DB" + return $ Settings { sGhcNameVersion = GhcNameVersion { ghcNameVersion_programName = "ghc" ===================================== hadrian/src/Rules/BinaryDist.hs ===================================== @@ -222,11 +222,12 @@ bindistRules = do -- Regenerate settings file without LibDir. For bindists, LibDir should -- be derived from topdir at runtime such that the GHC binary is - -- relocatable. + -- relocatable. The package DB is always at "package.conf.d" relative to + -- the lib dir, matching the known bindist layout. let bindistSettings = bindistFilesDir -/- "lib" -/- "settings" bindistContext = vanillaContext Stage1 compiler bindistSettingsContent <- interpretInContext bindistContext $ - generateSettings bindistSettings False (bindistFilesDir -/- "lib" -/- "package.conf.d") + generateSettings bindistSettings False "package.conf.d" writeFile' bindistSettings bindistSettingsContent copyDirectory (rtsIncludeDir) bindistFilesDir ===================================== hadrian/src/Rules/Generate.hs ===================================== @@ -266,7 +266,11 @@ generateRules = do Stage1 -> get_pkg_db Stage1 Stage2 -> get_pkg_db Stage1 Stage3 -> get_pkg_db Stage2 - go (generateSettings out True pkgDb) out + -- addTrailingPathSeparator needed: makeRelativeNoSysLink uses + -- splitPath where "lib" and "lib/" are distinct components. + let lib_topDir = addTrailingPathSeparator prefix + relPkgDb = makeRelativeNoSysLink lib_topDir pkgDb + go (generateSettings out True relPkgDb) out (prefix -/- "targets" -/- "default.target") %> \out -> go (show <$> expr getTargetTarget) out where @@ -470,11 +474,12 @@ ghcWrapper stage = do -- | Generate settings file, optionally including @LibDir@. -- --- @pkgDb@: absolute path to the package DB for the @"Relative Global Package --- DB"@ setting. Callers determine the correct path (in-tree or bindist). For +-- @rel_pkg_db@: package DB path relative to the lib dir (e.g. +-- "package.conf.d"). Callers supply the correct relative path. For bindists +-- the layout is known statically; for in-tree builds callers compute it. For -- bindists, we omit @LibDir@ so it defaults to @topDir@ at runtime. generateSettings :: FilePath -> Bool -> FilePath -> Expr String -generateSettings settingsFile includeLibDir package_db_path = do +generateSettings settingsFile includeLibDir rel_pkg_db = do ctx <- getContext stage <- getStage @@ -486,12 +491,13 @@ generateSettings settingsFile includeLibDir package_db_path = do Stage2 -> pkgUnitId Stage1 base Stage3 -> pkgUnitId Stage2 base - let rel_pkg_db = makeRelativeNoSysLink (dropFileName settingsFile) package_db_path - -- E.g. the Stage2 compiler lives in _build/stage1 + let -- 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 - lib_topDir :: FilePath <- expr $ stageLibPath stage_dir_stage + -- addTrailingPathSeparator is needed because makeRelativeNoSysLink uses + -- splitPath internally, where "lib" and "lib/" are distinct components. + lib_topDir :: FilePath <- expr $ addTrailingPathSeparator <$> stageLibPath stage_dir_stage let rel_lib_topDir = makeRelativeNoSysLink (dropFileName settingsFile) lib_topDir settings <- traverse sequence $ ===================================== libraries/ghc-boot/GHC/Settings/Utils.hs ===================================== @@ -3,6 +3,7 @@ module GHC.Settings.Utils where import Prelude -- See Note [Why do we import Prelude here?] import Data.Char (isSpace) +import Data.Either (fromRight) import Data.Map (Map) import qualified Data.Map as Map @@ -45,7 +46,10 @@ getTargetArchOS target = tgtArchOs target getGlobalPackageDb :: FilePath -> RawSettings -> Either String FilePath getGlobalPackageDb settingsFile settings = do rel_db <- getRawSetting settingsFile settings "Relative Global Package DB" - return (dropFileName settingsFile </> rel_db) + let top_dir = dropFileName settingsFile + lib_dir = (top_dir </>) $ fromRight "." $ + getRawFilePathSetting top_dir settingsFile settings "LibDir" + return (lib_dir </> rel_db) -------------------------------------------------------------------------------- -- lib/settings ===================================== testsuite/tests/ghc-api/settings/LibDir.hs ===================================== @@ -0,0 +1,130 @@ +module Main where + +import Control.Monad (when) +import Control.Monad.IO.Class (liftIO) +import Data.List (intercalate) +import GHC +import GHC.Driver.DynFlags +import GHC.Driver.Env (hsc_dflags) +import GHC.Settings +import System.Directory +import System.Environment +import System.Exit (ExitCode (ExitFailure), exitWith) +import System.FilePath +import System.IO (hPutStrLn, stderr) +import System.Process (readProcess) +import Unsafe.Coerce (unsafeCoerce) + +-- Verify that a LibDir setting in the settings file is respected: +-- 1. fileSettings_libDir and fileSettings_globalPackageDatabase reflect the +-- configured LibDir path (not topDir) +-- 2. GHC can still compile with a LibDir that differs from topDir +-- 3. --print-libdir and --print-global-package-db output the correct paths +-- +-- We create a symlink to the real lib dir so that the package DB remains +-- findable, but use a separate topDir so that topDir ≠ libDir, proving +-- the LibDir setting is actually used. +-- +-- Tested for both relative and absolute LibDir values. +main :: IO () +main = do + libdir : ghcBin : _ <- getArgs + + (rawSettingOpts, rawTargetOpts, realLibDir) <- runGhc (Just libdir) $ do + dflags <- hsc_dflags <$> getSession + pure (rawSettings dflags, rawTarget dflags, fileSettings_libDir (fileSettings dflags)) + + tmpDir <- getTemporaryDirectory + let topDir = tmpDir </> "T19174_top" + symlinkLib = tmpDir </> "T19174_lib" + -- Remove stale dirs from prior runs; createDirectoryLink fails if path exists. + removePathForcibly topDir + removePathForcibly symlinkLib + createDirectoryIfMissing True (topDir </> "targets") + createDirectoryLink realLibDir symlinkLib + + let testWithLibDir libDirValue = do + writeTopDirFiles topDir rawSettingOpts rawTargetOpts libDirValue + runGhc (Just topDir) $ do + assertSettings topDir symlinkLib + compileAndRunTestExpr + assertGhcFlags ghcBin topDir symlinkLib + + testWithLibDir (".." </> takeFileName symlinkLib) + testWithLibDir symlinkLib + + putStrLn "OK" + +writeTopDirFiles :: + (Show a) => + FilePath -> + [(String, String)] -> + a -> + String -> + IO () +writeTopDirFiles topDir rawSettingOpts rawTargetOpts libDirValue = do + let settings = filter ((/= "LibDir") . fst) rawSettingOpts ++ [("LibDir", libDirValue)] + writeFile (topDir </> "settings") $ + "[" ++ intercalate "\n," (map show settings) ++ "]" + writeFile (topDir </> "targets" </> "default.target") $ + show rawTargetOpts + +assertSettings :: FilePath -> FilePath -> Ghc () +assertSettings topDir expectedLib = do + dflags <- hsc_dflags <$> getSession + let fs = fileSettings dflags + actualLib = fileSettings_libDir fs + actualPkgDb = fileSettings_globalPackageDatabase fs + normActualLib <- liftIO $ canonicalizePath actualLib + normExpected <- liftIO $ canonicalizePath expectedLib + normTopDir <- liftIO $ canonicalizePath topDir + normActualPkgDb <- liftIO $ canonicalizePath actualPkgDb + normExpectedPkgDb <- liftIO $ canonicalizePath (expectedLib </> "package.conf.d") + liftIO $ do + when (normActualLib /= normExpected) $ + die + [ "FAIL: libDir should be " ++ normExpected, + " got " ++ normActualLib + ] + when (normActualLib == normTopDir) $ + die ["FAIL: libDir equals topDir — LibDir setting was ignored"] + when (normActualPkgDb /= normExpectedPkgDb) $ + die + [ "FAIL: globalPackageDB should be " ++ normExpectedPkgDb, + " got " ++ normActualPkgDb + ] + +assertGhcFlags :: FilePath -> FilePath -> FilePath -> IO () +assertGhcFlags ghcBin topDir expectedLib = do + normExpectedLib <- canonicalizePath expectedLib + normExpectedPkgDb <- canonicalizePath (expectedLib </> "package.conf.d") + + printedLibDir <- trim <$> readProcess ghcBin ["-B" ++ topDir, "--print-libdir"] "" + normPrintedLib <- canonicalizePath printedLibDir + when (normPrintedLib /= normExpectedLib) $ + die + [ "FAIL: --print-libdir should be " ++ normExpectedLib, + " got " ++ normPrintedLib + ] + + printedPkgDb <- trim <$> readProcess ghcBin ["-B" ++ topDir, "--print-global-package-db"] "" + normPrintedPkgDb <- canonicalizePath printedPkgDb + when (normPrintedPkgDb /= normExpectedPkgDb) $ + die + [ "FAIL: --print-global-package-db should be " ++ normExpectedPkgDb, + " got " ++ normPrintedPkgDb + ] + +compileAndRunTestExpr :: Ghc () +compileAndRunTestExpr = do + dflags <- getSessionDynFlags + _ <- setSessionDynFlags dflags + setContext [IIDecl (simpleImportDecl (mkModuleName "Prelude"))] + result <- compileExpr "length [1,2,3 :: Int]" + liftIO $ print (unsafeCoerce result :: Int) + +trim :: String -> String +trim = reverse . dropWhile (== '\n') . reverse + +die :: [String] -> IO () +die msgs = mapM_ (hPutStrLn stderr) msgs >> exitWith (ExitFailure 1) ===================================== testsuite/tests/ghc-api/settings/LibDir.stdout ===================================== @@ -0,0 +1,3 @@ +3 +3 +OK ===================================== testsuite/tests/ghc-api/settings/all.T ===================================== @@ -0,0 +1,10 @@ +test('LibDir', + [ extra_run_opts('"' + config.libdir + '" "' + config.compiler + '"') + , req_interp + # createDirectoryLink uses CreateSymbolicLink on Windows (requires developer + # mode or admin); also GHC searches for mingw relative to topDir, which our + # artificial topDir doesn't provide. + , when(opsys('mingw32'), skip) + ] + , compile_and_run + , ['-package ghc -package directory -package filepath']) View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/83f6a23fa4621b59fb04dec317aa5c8... -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/83f6a23fa4621b59fb04dec317aa5c8... 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