[Bug c++/55918] New: Stack partially unwound when noexcept causes call to std::terminate

[tobias at ringis dot se]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55918



             Bug #: 55918

           Summary: Stack partially unwound when noexcept causes call to

                    std::terminate

    Classification: Unclassified

           Product: gcc

           Version: 4.7.2

            Status: UNCONFIRMED

          Severity: normal

          Priority: P3

         Component: c++

        AssignedTo: unassig...@gcc.gnu.org

        ReportedBy: tob...@ringis.se





Created attachment 29123

  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=29123

Test program to illustrate the problem



When a noexcept function is "violated", std::terminate is called.  While the

standard allows for the stack to be fully unwound, partially unwound, or not

unwound at all, it is impossible to find the location where the exception was

thrown, unless the stack is left unwound.



GCC currently leaves the stack unwound in most cases, but in a very common

case, which is illustrated by the attached example program, the stack is

partially unwound.



If the noexcept is removed to allow the exception to propagate all the way past

main, std::terminate is called with the stack fully unwound, so it seems that

GCC is able to do what I want. It would be highly desirable for the noexcept

case to work in the same way as the unhandled exception case.



# g++ -std=c++0x -g tmp3.cpp

# gdb a.out

[...]

(gdb) bt

#0  0x000000318f036285 in raise () from /lib64/libc.so.6

#1  0x000000318f037b9b in abort () from /lib64/libc.so.6

#2  0x00000031964bbc5d in __gnu_cxx::__verbose_terminate_handler() ()

   from /usr/lib64/libstdc++.so.6

#3  0x00000031964b9e16 in ?? () from /usr/lib64/libstdc++.so.6

#4  0x00000031964b8e49 in ?? () from /usr/lib64/libstdc++.so.6

#5  0x00000031964b973d in __gxx_personality_v0 ()

   from /usr/lib64/libstdc++.so.6

#6  0x000000319000f6fb in ?? () from /lib64/libgcc_s.so.1

#7  0x000000319000fb58 in _Unwind_Resume () from /lib64/libgcc_s.so.1

#8  0x0000000000400911 in level2 () at tmp3.cpp:16

#9  0x000000000040091a in level1 () at tmp3.cpp:20

#10 0x0000000000400925 in main () at tmp3.cpp:24



As you can see, bad_guy is not in the backtrace.



There are two simple modifications that makes the backtrace complete. The first

is to remove the noexcept from level1, and the second is to remove the Foo

declaration in level2 (or delete Foo's destructor).