[PPC] Fix PR24686 by failing assembly for an invalid relocation

PR24686 identifies a problem where a relocation expression is invalid
when not all of the symbols in the expression can be locally
resolved.  This causes the compiler to request a PC-relative half16ds
relocation, which is nonsensical for PowerPC.  This patch recognizes
this situation and ensures we fail the assembly cleanly.

Test case provided by Anton Blanchard.

llvm-svn: 251027

1 files changed, 7 insertions, 0 deletions

diff --git a/llvm/lib/Target/PowerPC/MCTargetDesc/PPCELFObjectWriter.cpp b/llvm/lib/Target/PowerPC/MCTargetDesc/PPCELFObjectWriter.cpp
index ebcea9af279..75ba12b5a83 100644
--- a/llvm/lib/Target/PowerPC/MCTargetDesc/PPCELFObjectWriter.cpp
+++ b/llvm/lib/Target/PowerPC/MCTargetDesc/PPCELFObjectWriter.cpp
@@ -113,6 +113,13 @@ unsigned PPCELFObjectWriter::GetRelocType(const MCValue &Target,
         break;
       }
       break;
+    case PPC::fixup_ppc_half16ds: {
+      raw_ostream &OS = *(new raw_fd_ostream(2, false));
+      Target.print(OS);
+      OS << "\n";
+      report_fatal_error("Invalid PC-relative half16ds relocation");
+      break;
+    }
     case FK_Data_4:
     case FK_PCRel_4:
       Type = ELF::R_PPC_REL32;