Revert "codeGen: Remove binutils<2.17 hack, fixes T11758"

This reverts commit e3e2e49a8f6952e1c8a19321c729c17b294d8c92.

I'm reverting because it makes ghc-stage2 seg-fault on
64-bit Windows machines.  Even ghc-stage2 --version seg-faults.

1 files changed, 14 insertions, 1 deletions

diff --git a/compiler/nativeGen/X86/CodeGen.hs b/compiler/nativeGen/X86/CodeGen.hs
index 2bfcd9a0c8..cd45d92418 100644
--- a/compiler/nativeGen/X86/CodeGen.hs
+++ b/compiler/nativeGen/X86/CodeGen.hs
@@ -2624,10 +2624,23 @@ genSwitch dflags expr targets
         let op = OpAddr (AddrBaseIndex (EABaseReg tableReg)
                                        (EAIndex reg (wORD_SIZE dflags)) (ImmInt 0))
 
-        return $ e_code `appOL` t_code `appOL` toOL [
+        return $ if is32bit || os == OSDarwin
+                 then e_code `appOL` t_code `appOL` toOL [
                                 ADD (intFormat (wordWidth dflags)) op (OpReg tableReg),
                                 JMP_TBL (OpReg tableReg) ids rosection lbl
                        ]
+                 else -- HACK: On x86_64 binutils<2.17 is only able to generate
+                      -- PC32 relocations, hence we only get 32-bit offsets in
+                      -- the jump table. As these offsets are always negative
+                      -- we need to properly sign extend them to 64-bit. This
+                      -- hack should be removed in conjunction with the hack in
+                      -- PprMach.hs/pprDataItem once binutils 2.17 is standard.
+                      e_code `appOL` t_code `appOL` toOL [
+                               MOVSxL II32 op (OpReg reg),
+                               ADD (intFormat (wordWidth dflags)) (OpReg reg)
+                                   (OpReg tableReg),
+                               JMP_TBL (OpReg tableReg) ids rosection lbl
+                       ]
   | otherwise
   = do
         (reg,e_code) <- getSomeReg (cmmOffset dflags expr offset)