GitLab

Magnus pushed to branch wip/mangoiv/aarch64-longjump at Glasgow Haskell Compiler / GHC

Commits:

49b7019d

by mangoiv at 2026-05-11T14:20:33+02:00

driver: enable -finter-module-far-jumps by default

this fixes a compatibility bug with certain binutils/gcc versions where
we were seeing jump offset overflow errors.
This commit can probably reverted if we stop supporting the problematic
binutils/gcc verions (2.44 and 14.2, respectively)

Reolves #26994

2 changed files:

+ changelog.d/inter-module-far-jumps-aarch64-default
compiler/GHC/Driver/DynFlags.hs

Changes:

changelog.d/inter-module-far-jumps-aarch64-default

 +section: driver
 +synopsis: enable -finter-module-far-jumps by default on aarch64
 +issues: #26994
 +description: Some binutils and gcc versions lead to jump offset erros on aarch64 profiled/dynamic ways. To mitigate this bug, we enable inter-module-far-jumps by default on this platform.

compiler/GHC/Driver/DynFlags.hs

@@ -1233,6 +1233,11 @@ defaultFlags settings
        Opt_SpecialiseIncoherents,
        Opt_WriteSelfRecompInfo
+     ]
 +    {- note(mangoiv):
 +     - on aarch64 profiled-dynamic, we are seeing jump offset overflow
 +     - errors on certain binutils versions. This can probably be deactivated
 +     - if we stop supporting binutils 2.44 / GCC 14.2 -}
 +    ++ [ Opt_InterModuleFarJumps | platformArch platform == ArchAArch64 ]
      ++ [f | (ns,f) <- optLevelFlags, 0 `elem` ns]
               -- The default -O0 options
@@ -1245,6 +1250,7 @@ defaultFlags settings
      ++ validHoleFitDefaults
      where platform = sTargetPlatform settings
 +          defaultWays = ways $ defaultDynFlags settings
  -- | These are the default settings for the display and sorting of valid hole
  --  fits in typed-hole error messages. See Note [Valid hole fits include ...]