[PowerPC] Support .reloc *, R_PPC{,64}_NONE, *

This can be used to create references among sections. When --gc-sections
is used, the referenced section will be retained if the origin section
is retained.

llvm-svn: 360990
diff --git a/llvm/lib/Target/PowerPC/MCTargetDesc/PPCELFObjectWriter.cpp b/llvm/lib/Target/PowerPC/MCTargetDesc/PPCELFObjectWriter.cpp
index aa7b05b..042ddf4 100644
--- a/llvm/lib/Target/PowerPC/MCTargetDesc/PPCELFObjectWriter.cpp
+++ b/llvm/lib/Target/PowerPC/MCTargetDesc/PPCELFObjectWriter.cpp
@@ -133,6 +133,9 @@
   } else {
     switch ((unsigned)Fixup.getKind()) {
       default: llvm_unreachable("invalid fixup kind!");
+    case FK_NONE:
+      Type = ELF::R_PPC_NONE;
+      break;
     case PPC::fixup_ppc_br24abs:
       Type = ELF::R_PPC_ADDR24;
       break;