[Bug c++/62192] New: Segmentation fault when linking with Qt libraries

["lakjdsfiudslkfj at mailinator dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62192

            Bug ID: 62192
           Summary: Segmentation fault when linking with Qt libraries
           Product: gcc
           Version: 4.7.4
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: lakjdsfiudslkfj at mailinator dot com

Created attachment 33363
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33363&action=edit
gdb backtrace

Hi,

I'm currently having some difficulties linking to my library when my main
executable is linked with some Qt libraries. I'm running FreeBSD 10 and gcc47
but the latest 410 package for FreeBSD exhibits the same behavior.

My main.cc looks like this:

---
#include "foo.h"

int main() {
  foo();
}
---

My library libfoo consists of a file foo.cc:

---
#include <string>
#include <iostream>

void foo() {
  std::string lol = "test";
  std::cout << lol << std::endl;;
}
---

foo.h for completeness:
--
void foo();
--

and is compiled via
g++ -g -c -fPIC foo.cc -o libfoo.o
g++ -shared -fPIC libfoo.o -o libfoo.so

After this my main.cc is compiled/linked:

g++ -g -O0 -I/tmp/delme2 -DQT_SHARED -I/usr/local/include/qt4
-I/usr/local/include/qt4/QtCore -L/usr/local/lib/qt4 -lQtCore -L/tmp/delme2
-lfoo main.cc

running a.out yields "segmentation fault (core dumped)  ./a.out"

with clang++ -g -O0 -I/tmp/delme2 -DQT_SHARED -I/usr/local/include/qt4
-I/usr/local/include/qt4/QtCore -L/usr/local/lib/qt4 -lQtCore -L/tmp/delme2
-lfoo main.cc

the output is "test" as expected.

It also works when I remove the Qt libraries, i.e.
g++ -g -O0 -I/usr/local/include -I/tmp/delme2 -L/tmp/delme2 -lfoo main.cc

Am I doing something wrong here? Is it a Qt problem rather than gcc? But why
does it work with clang then? I attached a GDB backtrace just in case.