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

Commits:

• a4ef4465
  by Duncan Coutts at 2026-05-01T11:47:11+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.
  

• c542c4c0
  by Duncan Coutts at 2026-05-01T11:47:11+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).
  

5 changed files:

• hadrian/src/Rules/Generate.hs
• hadrian/src/Rules/Library.hs
• hadrian/src/Rules/Rts.hs
• rts/.gitignore
• + rts/win32/libHSghc-internal.def.in

Changes:

     , 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

 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

   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

             "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

             (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

 /ghcautoconf.h.autoconf.in

 /ghcautoconf.h.autoconf

 /include/ghcautoconf.h

+/win32/libHSghc-internal.def

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

+

+EXPORTS

+    init_ghc_hs_iface