Allow FDE references outside the +/-2GB range supported by PC relative

offsets for code models other than small/medium. For JIT application,
memory layout is less controlled and can result in truncations
otherwise. 

Patch from Akos Kiss.

Differential Revision: http://reviews.llvm.org/D6079


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222538 91177308-0d34-0410-b5e6-96231b3b80d8

lib/MC/MCObjectFileInfo.cpp

@@ -273,6 +273,17 @@ void MCObjectFileInfo::InitELFMCObjectFileInfo(Triple T) {
   case Triple::mips64el:
     FDECFIEncoding = dwarf::DW_EH_PE_sdata8;
     break;
+  case Triple::x86_64:
+    if (RelocM == Reloc::PIC_) {
+      FDECFIEncoding = dwarf::DW_EH_PE_pcrel |
+        ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
+         ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
+    } else {
+      FDECFIEncoding =
+        (CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
+        ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
+    }
+    break;
   default:
     FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
     break;