From d179886f0595eb3564a9edfdfff79def130d89cc Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Fri, 29 Oct 2010 23:09:31 +0000
Subject: [PATCH] Be more strict on when we produce an undefined reference. In
 gas a file with just

.type   foo,@object

will produce an undefined reference to foo. On the other hand, a file with
just

.weakref bar, foo

will not. It is somewhat hard to support both in MC since both statements
should create the symbols. It should be possible if we really need to by
adding to the flags, but hopefully that is not necessary.

With this patch we do not produce a undefined reference in any of those cases.
The assembly file needs an actual use for the undefined reference to be
present.

This is in preparation for a patch implementing .weakref.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117735 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/MC/ELFObjectWriter.cpp | 5 ++++-
 test/MC/ELF/alias.s        | 1 +
 test/MC/ELF/size.s         | 3 ++-
 test/MC/ELF/undef.s        | 1 +
 4 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/lib/MC/ELFObjectWriter.cpp b/lib/MC/ELFObjectWriter.cpp
index dbe0dd870f6..2fca31104a8 100644
--- a/lib/MC/ELFObjectWriter.cpp
+++ b/lib/MC/ELFObjectWriter.cpp
@@ -868,8 +868,11 @@ static bool isInSymtab(const MCAssembler &Asm, const MCSymbolData &Data,
 
   const MCSymbol &Symbol = Data.getSymbol();
 
+  if (Symbol.getName() == "_GLOBAL_OFFSET_TABLE_")
+    return true;
+
   const MCSymbol &A = AliasedSymbol(Symbol);
-  if (&A != &Symbol && A.isUndefined())
+  if (!A.isVariable() && A.isUndefined() && !Data.isCommon())
     return false;
 
   if (!Asm.isSymbolLinkerVisible(Symbol) && !Symbol.isUndefined())
diff --git a/test/MC/ELF/alias.s b/test/MC/ELF/alias.s
index 84b558822da..98ef50b50f5 100644
--- a/test/MC/ELF/alias.s
+++ b/test/MC/ELF/alias.s
@@ -15,6 +15,7 @@ bar3 = foo3
 foo4:
 bar4 = foo4
 
+        .long foo2
 // CHECK:       # Symbol 0x00000001
 // CHECK-NEXT:  (('st_name', 0x00000005) # 'bar'
 // CHECK-NEXT:   ('st_bind', 0x00000000)
diff --git a/test/MC/ELF/size.s b/test/MC/ELF/size.s
index 7ad13361b7e..ceb9486c302 100644
--- a/test/MC/ELF/size.s
+++ b/test/MC/ELF/size.s
@@ -6,4 +6,5 @@
 // CHECK-NEXT:    (('st_name', 0x00000001) # 'foo'
 // CHECK-NEXT:     ('st_bind', 0x00000001)
 
-	.size	foo, .Lbar-foo
+	.size foo, .Lbar-foo
+        .long foo
diff --git a/test/MC/ELF/undef.s b/test/MC/ELF/undef.s
index 01aeac664d6..cdef5e47393 100644
--- a/test/MC/ELF/undef.s
+++ b/test/MC/ELF/undef.s
@@ -10,6 +10,7 @@
 
 	.type	.Lsym5,@object
         .type   sym6,@object
+        .long sym6
 
 	.section	.rodata.str1.1,"aMS",@progbits,1
 .Lsym7:
-- 
2.34.1