Don't error if __tls_get_addr is defined.

Turns out some systems do define it. Not producing an error in this
case matches gold and bfd.

llvm-svn: 287125

lld/ELF/SymbolTable.cpp

@@ -137,7 +137,8 @@ DefinedRegular<ELFT> *SymbolTable<ELFT>::addAbsolute(StringRef Name,
 template <class ELFT>
 DefinedRegular<ELFT> *SymbolTable<ELFT>::addIgnored(StringRef Name,
                                                     uint8_t Visibility) {
-  if (!find(Name))
+  SymbolBody *S = find(Name);
+  if (!S || !S->isUndefined())
     return nullptr;
   return addAbsolute(Name, Visibility);
 }

lld/test/ELF/defined-tls_get_addr.s

@@ -0,0 +1,10 @@
+// RUN: llvm-mc %s -o %t.o -triple x86_64-pc-linux -filetype=obj
+// RUN: ld.lld %t.o -o %t
+
+// Don't error if __tls_get_addr is defined.
+
+.global _start
+.global __tls_get_addr
+_start:
+__tls_get_addr:
+nop