Index: lib/Target/AArch64/MCTargetDesc/AArch64ELFObjectWriter.cpp
===================================================================
--- lib/Target/AArch64/MCTargetDesc/AArch64ELFObjectWriter.cpp
+++ lib/Target/AArch64/MCTargetDesc/AArch64ELFObjectWriter.cpp
@@ -61,6 +61,8 @@
 
   if (IsPCRel) {
     switch ((unsigned)Fixup.getKind()) {
+    case FK_Data_1:
+      report_fatal_error("unsupported relocation type: FK_Data_1");
     case FK_Data_2:
       return ELF::R_AARCH64_PREL16;
     case FK_Data_4:
@@ -97,6 +99,8 @@
     }
   } else {
     switch ((unsigned)Fixup.getKind()) {
+    case FK_Data_1:
+      report_fatal_error("unsupported relocation type: FK_Data_1");
     case FK_Data_2:
       return ELF::R_AARCH64_ABS16;
     case FK_Data_4:
Index: test/MC/AArch64/invalid-relocation.s
===================================================================
--- /dev/null
+++ test/MC/AArch64/invalid-relocation.s
@@ -0,0 +1,6 @@
+# RUN: not llvm-mc -triple aarch64-elf -filetype obj -o /dev/null 2>&1 %s \
+# RUN:     | FileCheck %s
+
+.byte("a")
+
+# CHECK: LLVM ERROR: unsupported relocation type: FK_Data_1