From 1d5969d839ddc4d0af93fd035aa13131e5c6fa82 Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Fri, 9 Dec 2011 03:03:58 +0000
Subject: [PATCH] Handle the case of the magical _GLOBAL_OFFSET_TABLE_ showing
 up in a symbol difference. This matches gas behavior and fixes PR11513.

We still don't handle _GLOBAL_OFFSET_TABLE_ in data sections.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146238 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/MC/ELFObjectWriter.cpp   | 25 ++++++++++++++++++-------
 test/MC/ELF/relocation-386.s |  6 ++++++
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/lib/MC/ELFObjectWriter.cpp b/lib/MC/ELFObjectWriter.cpp
index 935ef4209d4..14ca509d75f 100644
--- a/lib/MC/ELFObjectWriter.cpp
+++ b/lib/MC/ELFObjectWriter.cpp
@@ -1742,14 +1742,25 @@ unsigned X86ELFObjectWriter::GetRelocType(const MCValue &Target,
     }
   } else {
     if (IsPCRel) {
-      switch (Modifier) {
-      default:
-        llvm_unreachable("Unimplemented");
-      case MCSymbolRefExpr::VK_None:
-        Type = ELF::R_386_PC32;
+      switch ((unsigned)Fixup.getKind()) {
+      default: llvm_unreachable("invalid fixup kind!");
+
+      case X86::reloc_global_offset_table:
+        Type = ELF::R_386_GOTPC;
         break;
-      case MCSymbolRefExpr::VK_PLT:
-        Type = ELF::R_386_PLT32;
+
+      case FK_PCRel_4:
+      case FK_Data_4:
+        switch (Modifier) {
+        default:
+          llvm_unreachable("Unimplemented");
+        case MCSymbolRefExpr::VK_None:
+          Type = ELF::R_386_PC32;
+          break;
+        case MCSymbolRefExpr::VK_PLT:
+          Type = ELF::R_386_PLT32;
+          break;
+        }
         break;
       }
     } else {
diff --git a/test/MC/ELF/relocation-386.s b/test/MC/ELF/relocation-386.s
index 442176307fa..7604f9e1516 100644
--- a/test/MC/ELF/relocation-386.s
+++ b/test/MC/ELF/relocation-386.s
@@ -160,6 +160,11 @@
 // CHECK-NEXT:  ('r_sym', 0x00000d)
 // CHECK-NEXT:  ('r_type', 0x21)
 // CHECK-NEXT: ),
+// Relocation 25 (_GLOBAL_OFFSET_TABLE_-bar2) is of type R_386_GOTPC.
+// CHECK-NEXT: Relocation 25
+// CHECK-NEXT: (('r_offset', 0x00000094)
+// CHECK-NEXT:  ('r_sym', 0x00000b)
+// CHECK-NEXT:  ('r_type', 0x0a)
 
 // Section 4 is bss
 // CHECK:      # Section 4
@@ -225,6 +230,7 @@ bar2:
         movl zed@DTPOFF(%eax), %eax
         pushl $bar
         addl foo@GOTTPOFF(%edx), %eax
+        subl    _GLOBAL_OFFSET_TABLE_-bar2, %ebx
 
         .section        zedsec,"awT",@progbits
 zed: