[Bug libstdc++/56557] New: Link error about `std::fstream' or `std::stringstream' with `-flto' and `-rdynamic' options

[ai.azuma at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56557

             Bug #: 56557
           Summary: Link error about `std::fstream' or `std::stringstream'
                    with `-flto' and `-rdynamic' options
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: ai.azuma@gmail.com


Created attachment 29605
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=29605
Output of -v option

The following code results in a link error when compiling on GCC 4.8.0 20130303
with `-flto' and `-rdynamic' options;

//================
#include <fstream>

int main()
{
  std::fstream x;
}
//================

The link error is;

cryolite@ubuntu:~/work/gcc-bugs/20130306$ ~/local/gcc-4.8-20130303/bin/g++
-flto -rdynamic main.cpp
/usr/bin/ld: a.out: hidden symbol
`_ZTCSt13basic_fstreamIcSt11char_traitsIcEE0_Sd' isn't defined
/usr/bin/ld: final link failed: Bad value
collect2: error: ld returned 1 exit status

Other specializations of `std::basic_fstream' or `std::basic_stringstream' have
the similar issue.

As far as I can confirm, this problem is not reproduced with 4.6.4 20130301 or
4.7.3 20130302. Thus, this seems a regression.