test/CodeGenCXX/PR6677.cpp

// RUN: %clang_cc1 %s -triple=x86_64-apple-darwin10 -emit-llvm -o - | FileCheck %s

// CHECK-NOT: @_ZTVN5test118stdio_sync_filebufIwEE = constant
// CHECK: @_ZTVN5test018stdio_sync_filebufIwEE = constant

namespace test0 {
  struct  basic_streambuf   {
    virtual       ~basic_streambuf();
  };
  template<typename _CharT >
  struct stdio_sync_filebuf : public basic_streambuf {
    virtual void      xsgetn();
  };

  // This specialization should cause the vtable to be emitted, even with
  // the following extern template declaration.
  template<> void stdio_sync_filebuf<wchar_t>::xsgetn()  {
  }
  extern template class stdio_sync_filebuf<wchar_t>;
}

namespace test1 {
  struct  basic_streambuf   {
    virtual       ~basic_streambuf();
  };
  template<typename _CharT >
  struct stdio_sync_filebuf : public basic_streambuf {
    virtual void      xsgetn();
  };

  // Just a declaration should not force the vtable to be emitted.
  template<> void stdio_sync_filebuf<wchar_t>::xsgetn();
}