From bf052ac5d1c8f21075bc675f629709c20791c5f7 Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Wed, 27 Oct 2010 16:04:30 +0000
Subject: [PATCH] Symbols defined as the difference of other two end up in the
 ABS section.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117451 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/MC/ELFObjectWriter.cpp |  7 ++-----
 test/MC/ELF/abs.s          | 16 ++++++++++++++++
 2 files changed, 18 insertions(+), 5 deletions(-)
 create mode 100644 test/MC/ELF/abs.s

diff --git a/lib/MC/ELFObjectWriter.cpp b/lib/MC/ELFObjectWriter.cpp
index 5e11a1553f8..54d8123da02 100644
--- a/lib/MC/ELFObjectWriter.cpp
+++ b/lib/MC/ELFObjectWriter.cpp
@@ -863,7 +863,7 @@ void ELFObjectWriterImpl::ComputeSymbolTable(MCAssembler &Asm) {
     if (it->isCommon()) {
       assert(!Local);
       MSD.SectionIndex = ELF::SHN_COMMON;
-    } else if (Symbol.isAbsolute()) {
+    } else if (Symbol.isAbsolute() || RefSymbol.isVariable()) {
       MSD.SectionIndex = ELF::SHN_ABS;
     } else if (RefSymbol.isUndefined()) {
       MSD.SectionIndex = ELF::SHN_UNDEF;
@@ -871,11 +871,8 @@ void ELFObjectWriterImpl::ComputeSymbolTable(MCAssembler &Asm) {
       // are able to set it.
       if (GetBinding(*it) == ELF::STB_LOCAL)
         SetBinding(*it, ELF::STB_GLOBAL);
-    } else if (Symbol.isVariable()) {
-      MSD.SectionIndex = SectionIndexMap.lookup(&RefSymbol.getSection());
-      assert(MSD.SectionIndex && "Invalid section index!");
     } else {
-      MSD.SectionIndex = SectionIndexMap.lookup(&Symbol.getSection());
+      MSD.SectionIndex = SectionIndexMap.lookup(&RefSymbol.getSection());
       assert(MSD.SectionIndex && "Invalid section index!");
     }
 
diff --git a/test/MC/ELF/abs.s b/test/MC/ELF/abs.s
new file mode 100644
index 00000000000..d7fa0c03882
--- /dev/null
+++ b/test/MC/ELF/abs.s
@@ -0,0 +1,16 @@
+// RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | elf-dump  | FileCheck %s
+
+// Test that zed will be an ABS symbol
+
+.Lfoo:
+.Lbar:
+        zed = .Lfoo - .Lbar
+
+// CHECK:      # Symbol 0x00000001
+// CHECK-NEXT: (('st_name', 0x00000001) # 'zed'
+// CHECK-NEXT:  ('st_bind', 0x00000000)
+// CHECK-NEXT:  ('st_type', 0x00000000)
+// CHECK-NEXT:  ('st_other', 0x00000000)
+// CHECK-NEXT:  ('st_shndx', 0x0000fff1)
+// CHECK-NEXT:  ('st_value', 0x00000000)
+// CHECK-NEXT:  ('st_size', 0x00000000)