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David Eichmann pushed to branch wip/dcoutts/windows-rts-dll at Glasgow Haskell Compiler / GHC

Commits:

813ce36c

by Duncan Coutts at 2026-05-06T11:31:56+01:00

Add minimal dlltool support into ./configure

Find dlltool, and hopefully support finding it within the bundled llvm
toolchain on windows.

4cfe78cd

by Duncan Coutts at 2026-05-06T11:31:56+01:00

Update the default host and target files for dlltool support

82880197

by Duncan Coutts at 2026-05-06T11:31:56+01:00

Add dlltool as a hadrian builder

Optional except on windows.

b6bdebf9

by Duncan Coutts at 2026-05-06T11:31:56+01:00

Update and generate libHSghc-internal.def from .def.in file

The only symbol that the rts imports from the ghc-internal package now
is init_ghc_hs_iface. So the rts only needs an import lib that defines
that one symbol.

Also, remove the libHSghc-prim.def because it is redundant. The rts no
longer imports anything from ghc-prim.

Keep libHSffi.def for now. We may yet need it once it is clear how
libffi is going to be built/used for ghc.

a71ea50e

by Duncan Coutts at 2026-05-06T11:31:56+01:00

Add rule to build libHSghc-internal.dll.a and link into the rts

On windows only, with dynamic linking.

This is needed because on windows, all symbols in dlls must be resolved.
No dangling symbols allowed. References to external symbols must be
explicit. We resolve this with an import library. We create an import
library for ghc-internal, a .dll.a file. This is a static archive
containing .o files that define the symbols we need, and crucially have
".idata" sections that specifies the symbols the dll imports and from
where.

Note that we do not install this libHSghc-internal.dll.a, and it does
not need to list all the symbols exported by that package. We create a
special purpose import lib and only use it when linking the rts dll, so
it only has to list the symbols that the rts uses from ghc-internal
(which is exactly one symbol: init_ghc_hs_iface).

Changes:

configure.ac

@@ -314,13 +314,16 @@ else
      AC_CHECK_TOOL([RANLIB],[ranlib])
      AC_CHECK_TOOL([OBJDUMP],[objdump])
      AC_CHECK_TOOL([WindresCmd],[windres])
 +    AC_CHECK_TOOL([DlltoolCmd],[llvm-dlltool])
      AC_CHECK_TOOL([Genlib],[genlib])
      if test "$HostOS" = "mingw32"; then
          AC_CHECK_TARGET_TOOL([WindresCmd],[windres])
 +        AC_CHECK_TARGET_TOOL([DlltoolCmd],[llvm-dlltool])
          AC_CHECK_TARGET_TOOL([OBJDUMP],[objdump])
          WindresCmd="$(cygpath -m $WindresCmd)"
 +        DlltoolCmd="$(cygpath -m $DlltoolCmd)"
          if test "$Genlib" != ""; then
              GenlibCmd="$(cygpath -m $Genlib)"
@@ -1080,9 +1083,10 @@ echo "\
        libdw   : $UseLibdw
     Using LLVM tools
 -      llc   : $LlcCmd
 -      opt   : $OptCmd
 -      llvm-as : $LlvmAsCmd"
 +      llc          : $LlcCmd
 +      opt          : $OptCmd
 +      llvm-as      : $LlvmAsCmd
 +      llvm-dlltool : $DlltoolCmd"
  if test "$HSCOLOUR" = ""; then
  echo "

distrib/configure.ac.in

@@ -229,6 +229,12 @@ FIND_LLVM_PROG([LLVMAS], [clang], [$LlvmMinVersion], [$LlvmMaxVersion])
  LlvmAsCmd="$LLVMAS"
  AC_SUBST([LlvmAsCmd])
 +dnl ** Which LLVM llvm-dlltool to use?
 +dnl --------------------------------------------------------------
 +AC_ARG_VAR(DlltoolCmd,[Use as the path to LLVM's llvm-dlltool [default=autodetect]])
 +FIND_LLVM_PROG([DlltoolCmd], [llvm-dlltool], [$LlvmMinVersion], [$LlvmMaxVersion])
 +AC_SUBST([DlltoolCmd])
++
  dnl We know that `clang` supports `--target` and it is necessary to pass it
  dnl lest we see #25793.
  if test -z "$LlvmAsFlags" && ! test -z "$LlvmTarget"; then

hadrian/cfg/default.host.target.in

@@ -45,6 +45,7 @@ Target
  , tgtOpt = Nothing
  , tgtLlvmAs = Nothing
  , tgtWindres = Nothing
 +, tgtDlltool = Nothing
  , tgtOtool = Nothing
  , tgtInstallNameTool = Nothing
+ }

hadrian/cfg/default.target.in

@@ -45,6 +45,7 @@ Target
  , tgtOpt = @OptCmdMaybeProg@
  , tgtLlvmAs = @LlvmAsCmdMaybeProg@
  , tgtWindres = @WindresCmdMaybeProg@
 +, tgtDlltool = @DlltoolCmdMaybeProg@
  , tgtOtool = @OtoolCmdMaybeProg@
  , tgtInstallNameTool = @InstallNameToolCmdMaybeProg@
+ }

hadrian/src/Builder.hs

@@ -17,7 +17,7 @@ import Development.Shake.Classes
  import Development.Shake.Command
  import Development.Shake.FilePath
  import GHC.Generics
 -import GHC.Platform.ArchOS (ArchOS(..), Arch(..))
 +import GHC.Platform.ArchOS (ArchOS(..), Arch(..), OS(..))
  import qualified Hadrian.Builder as H
  import Hadrian.Builder hiding (Builder)
  import Hadrian.Builder.Ar
@@ -180,6 +180,7 @@ data Builder = Alex
               | Objdump
               | Python
               | Ranlib
 +             | Dlltool
               | Testsuite TestMode
               | Sphinx SphinxMode
               | Tar TarMode
@@ -418,6 +419,7 @@ isOptional target = \case
      Alex     -> True
      -- Most ar implemententions no longer need ranlib, but some still do
      Ranlib   -> not $ Toolchain.arNeedsRanlib (tgtAr target)
 +    Dlltool  -> archOS_OS (tgtArchOs target) /= OSMinGW32
      JsCpp    -> not $ (archOS_arch . tgtArchOs) target == ArchJavaScript -- ArchWasm32 too?
      _        -> False
@@ -442,6 +444,7 @@ systemBuilderPath builder = case builder of
      Objdump         -> fromKey "objdump"
      Python          -> fromKey "python"
      Ranlib          -> fromTargetTC "ranlib" (maybeProg Toolchain.ranlibProgram . tgtRanlib)
 +    Dlltool         -> fromTargetTC "dlltool" (maybeProg id . tgtDlltool)
      Testsuite _     -> fromKey "python"
      Sphinx _        -> fromKey "sphinx-build"
      Tar _           -> fromKey "tar"

hadrian/src/Rules/Generate.hs

@@ -377,6 +377,7 @@ templateRules = do
      , interpolateSetting "ProjectPatchLevel1" ProjectPatchLevel1
      , interpolateSetting "ProjectPatchLevel2" ProjectPatchLevel2
+     ]
 +  templateRule "rts/win32/libHSghc-internal.def" projectVersion
    templateRule "docs/index.html" $ packageUnitIds Stage1
    templateRule "docs/users_guide/ghc_config.py" $ mconcat
      [ projectVersion

hadrian/src/Rules/Library.hs

@@ -4,6 +4,8 @@ import Hadrian.BuildPath
  import Hadrian.Haskell.Cabal
  import Hadrian.Haskell.Cabal.Type
  import qualified Text.Parsec      as Parsec
 +import GHC.Platform.ArchOS (ArchOS(archOS_OS), OS(..))
 +import GHC.Toolchain.Target (Target(tgtArchOs))
  import Base
  import Context
@@ -185,9 +187,13 @@ jsObjects context = do
    srcs <- interpretInContext context (getContextData jsSrcs)
    mapM (objectPath context) srcs
 --- | Return extra object files needed to build the given library context. The
 --- resulting list is currently non-empty only when the package from the
 --- 'Context' is @ghc-internal@ built with in-tree GMP backend.
 +-- | Return extra object files needed to build the given library context.
 +--
 +-- This is non-empty for:
 +--
 +-- * @ghc-internal@ when built with in-tree GMP backend
 +-- * @rts@ on Windows when linking dynamically
 +--
  extraObjects :: Context -> Action [FilePath]
  extraObjects context
      | package context == ghcInternal = do
@@ -195,6 +201,13 @@ extraObjects context
              "gmp" -> gmpObjects (stage context)
              _     -> return []
 +    | package context == rts = do
 +          target   <- interpretInContext context getStagedTarget
 +          builddir <- buildPath context
 +          return [ builddir -/- "libHSghc-internal.dll.a"
 +                 | archOS_OS (tgtArchOs target) == OSMinGW32
 +                 , Dynamic `wayUnit` way context ]
++
      | otherwise = return []
  -- | Return all the object files to be put into the library we're building for

hadrian/src/Rules/Rts.hs

@@ -24,6 +24,20 @@ rtsRules = priority 3 $ do
              (addRtsDummyVersion $ takeFileName rtsLibFilePath')
              rtsLibFilePath'
 +    -- Solve the recursive dependency between the rts and ghc-internal
 +    -- on Windows by creating an import lib for the ghc-internal dll,
 +    -- to be linked into the rts dll.
 +    forM_ [Stage1, Stage2, Stage3 ] $ \ stage -> do
 +        let buildPath = root -/- buildDir (rtsContext stage)
 +        buildPath -/- "libHSghc-internal.dll.a" %> buildGhcInternalImportLib
++
 +buildGhcInternalImportLib :: FilePath -> Action ()
 +buildGhcInternalImportLib target = do
 +    let input  = "rts/win32/libHSghc-internal.def"
 +        output = target -- the .dll.a import lib
 +    need [input]
 +    runBuilder Dlltool ["-d", input, "-l", output] [input] [output]
++
  -- Need symlinks generated by rtsRules.
  needRtsSymLinks :: Stage -> Set.Set Way -> Action ()
  needRtsSymLinks stage rtsWays

m4/fp_setup_windows_toolchain.m4

@@ -131,8 +131,8 @@ AC_DEFUN([FP_SETUP_WINDOWS_TOOLCHAIN],[
      AR="${mingwbin}llvm-ar.exe"
      RANLIB="${mingwbin}llvm-ranlib.exe"
      OBJDUMP="${mingwbin}llvm-objdump.exe"
 -    DLLTOOL="${mingwbin}llvm-dlltool.exe"
      WindresCmd="${mingwbin}llvm-windres.exe"
 +    DlltoolCmd="${mingwbin}llvm-dlltool.exe"
      LLC="${mingwbin}llc.exe"
      OPT="${mingwbin}opt.exe"
      LLVMAS="${mingwbin}clang.exe"

m4/ghc_toolchain.m4

@@ -95,6 +95,7 @@ AC_DEFUN([FIND_GHC_TOOLCHAIN],
      echo "--merge-objs=$MergeObjsCmd" >> acargs
      echo "--readelf=$READELF" >> acargs
      echo "--windres=$WindresCmd" >> acargs
 +    echo "--dlltool=$DlltoolCmd" >> acargs
      echo "--llc=$LlcCmd" >> acargs
      echo "--opt=$OptCmd" >> acargs
      echo "--llvm-as=$LlvmAsCmd" >> acargs

m4/prep_target_file.m4

@@ -191,6 +191,7 @@ AC_DEFUN([PREP_TARGET_FILE],[
      PREP_MAYBE_SIMPLE_PROGRAM([OptCmd])
      PREP_MAYBE_PROGRAM([LlvmAsCmd], [LlvmAsFlags])
      PREP_MAYBE_SIMPLE_PROGRAM([WindresCmd])
 +    PREP_MAYBE_SIMPLE_PROGRAM([DlltoolCmd])
      PREP_MAYBE_SIMPLE_PROGRAM([OtoolCmd])
      PREP_MAYBE_SIMPLE_PROGRAM([InstallNameToolCmd])
      PREP_MAYBE_STRING([TargetVendor_CPP])

rts/.gitignore

@@ -20,3 +20,4 @@
  /ghcautoconf.h.autoconf.in
  /ghcautoconf.h.autoconf
  /include/ghcautoconf.h
 +/win32/libHSghc-internal.def

rts/win32/libHSghc-internal.def.in

 +LIBRARY libHSghc-internal-@ProjectVersionForLib@.0-ghc@ProjectVersion@.dll
++
 +EXPORTS
 +    init_ghc_hs_iface

utils/ghc-toolchain/exe/Main.hs

@@ -486,7 +486,7 @@ mkTarget opts = do
      -- for windows, also used for cross compiling
      windres <- optional $ findProgram "windres" (optWindres opts) ["windres"]
 -    dlltool <- optional $ findProgram "dlltool" (optDlltool opts) ["dlltool", "llvm-dlltool"]
 +    dlltool <- optional $ findProgram "dlltool" (optDlltool opts) ["llvm-dlltool"]
      -- Darwin-specific utilities
      (otool, installNameTool) <-