Produce a R_X86_64_PLT32 when needed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115541 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/ELFObjectWriter.cpp b/lib/MC/ELFObjectWriter.cpp
index c7b862f..7d956a9 100644
--- a/lib/MC/ELFObjectWriter.cpp
+++ b/lib/MC/ELFObjectWriter.cpp
@@ -581,7 +581,16 @@
   unsigned Type;
   if (Is64Bit) {
     if (IsPCRel) {
-      Type = ELF::R_X86_64_PC32;
+      switch (Modifier) {
+      case MCSymbolRefExpr::VK_None:
+        Type = ELF::R_X86_64_PC32;
+        break;
+      case MCSymbolRefExpr::VK_PLT:
+        Type = ELF::R_X86_64_PLT32;
+        break;
+      default:
+        llvm_unreachable("Unimplemented");
+      }
     } else {
       switch ((unsigned)Fixup.getKind()) {
       default: llvm_unreachable("invalid fixup kind!");
diff --git a/test/MC/ELF/plt.s b/test/MC/ELF/plt.s
new file mode 100644
index 0000000..2cbcf5a
--- /dev/null
+++ b/test/MC/ELF/plt.s
@@ -0,0 +1,14 @@
+// RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | elf-dump  | FileCheck %s
+
+// Test that this produces a R_X86_64_PLT32.
+
+	jmp	foo@PLT
+
+// CHECK:      ('_relocations', [
+// CHECK-NEXT:   # Relocation 0
+// CHECK-NEXT:    (('r_offset',
+// CHECK-NEXT:     ('r_sym',
+// CHECK-NEXT:     ('r_type', 4)
+// CHECK-NEXT:     ('r_addend',
+// CHECK-NEXT:    ),
+// CHECK-NEXT:   ])