Only warn about undefined symbols if the symbol has been used in a regular object file

binutils-2.20/gold/symtab.cc

 // symtab.cc -- the gold symbol table
 
 // Copyright 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
 // Written by Ian Lance Taylor <iant@google.com>.
 
 // This file is part of gold.
 
 // This program is free software; you can redistribute it and/or modify
 // it under the terms of the GNU General Public License as published by
 // the Free Software Foundation; either version 3 of the License, or
@@ skipping 2709 matching lines @@
     const std::set<std::string> &exceptions) const
 {
   const char* const real_prefix = "__real_";
   int undef_count = 0;
   for (Symbol_table_type::const_iterator p = this->table_.begin();
        p != this->table_.end();
        ++p)
     {
       Symbol *sym = p->second;
       if (sym->is_undefined() &&
+          sym->in_reg() &&
           sym->binding() != elfcpp::STB_WEAK &&
           exceptions.count(sym->name()) == 0 &&
           // @TODO(pdox): If --wrap is to be a supported user-visible feature,
           // then it should be implemented properly in the LLVM plugin.
           // For now, since we need to use --wrap for the self-build, just
           // ignore the undefined symbols that result from --wrap.
           strncmp(sym->name(), real_prefix, strlen(real_prefix)) != 0)
         {
           gold_undefined_symbol(sym);
           undef_count++;
@@ skipping 826 matching lines @@
 
 #ifdef HAVE_TARGET_64_BIG
 template
 void
 Warnings::issue_warning<64, true>(const Symbol* sym,
                                   const Relocate_info<64, true>* relinfo,
                                   size_t relnum, off_t reloffset) const;
 #endif
 
 } // End namespace gold.