[Bug libstdc++/50529] New: std::vector::erase invokes undefined behavior with empty range

[Bug libstdc++/50529] New: std::vector::erase invokes undefined behavior with empty range

[delong.j at fb dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50529

             Bug #: 50529
           Summary: std::vector::erase invokes undefined behavior with
                    empty range
    Classification: Unclassified
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: libstdc++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: delong.j@fb.com


If you call vector erase() with an empty range, it invokes std::move() with an
output iterator inside of the source range.  (I.e. it tries to move all the
elements onto themselves.)  This causes problems if some of the elements don't
support self move-assignment (e.g. if they are other std::vectors).

[Bug libstdc++/50529] [C++0x] std::vector::erase invokes undefined behavior with empty range

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50529

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2011-09-27
         AssignedTo|unassigned at gcc dot       |paolo.carlini at oracle dot
                   |gnu.org                     |com
            Summary|std::vector::erase invokes  |[C++0x] std::vector::erase
                   |undefined behavior with     |invokes undefined behavior
                   |empty range                 |with empty range
     Ever Confirmed|0                           |1

--- Comment #1 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-09-27 00:38:24 UTC ---
Ok, thanks, it's also an optimization.

[Bug libstdc++/50529] [C++0x] std::vector::erase invokes undefined behavior with empty range

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50529

--- Comment #2 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-09-27 00:45:12 UTC ---
deque too

[Bug libstdc++/50529] [C++0x] std::vector::erase invokes undefined behavior with empty range

[paolo at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50529

--- Comment #3 from paolo at gcc dot gnu.org <paolo at gcc dot gnu.org> 2011-09-27 02:39:42 UTC ---
Author: paolo
Date: Tue Sep 27 02:39:34 2011
New Revision: 179234

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=179234
Log:
2011-09-26  Paolo Carlini  <paolo.carlini@oracle.com>

    PR libstdc++/50529
    * include/bits/vector.tcc (vector<>::erase(iterator, iterator)):
    Fix to do nothing if the range is empty.
    * include/bits/stl_bvector.h: Likewise.
    * include/bits/deque.tcc: Likewise.
    * include/debug/vector: Adjust.
    * include/debug/deque: Likewise.
    * testsuite/23_containers/vector/modifiers/erase/50529.cc: New.
    * testsuite/23_containers/deque/modifiers/erase/50529.cc: Likewise.
    * testsuite/23_containers/deque/modifiers/erase/3.cc: Adjust.

Added:
    trunk/libstdc++-v3/testsuite/23_containers/deque/modifiers/erase/50529.cc
    trunk/libstdc++-v3/testsuite/23_containers/vector/modifiers/erase/50529.cc
Modified:
    trunk/libstdc++-v3/ChangeLog
    trunk/libstdc++-v3/include/bits/deque.tcc
    trunk/libstdc++-v3/include/bits/stl_bvector.h
    trunk/libstdc++-v3/include/bits/vector.tcc
    trunk/libstdc++-v3/include/debug/deque
    trunk/libstdc++-v3/include/debug/vector
    trunk/libstdc++-v3/testsuite/23_containers/deque/modifiers/erase/3.cc

[Bug libstdc++/50529] [C++0x] std::vector::erase invokes undefined behavior with empty range

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50529

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.7.0
           Severity|major                       |normal

--- Comment #4 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-09-27 02:40:53 UTC ---
Done.

[Bug libstdc++/50529] [C++0x] std::vector::erase invokes undefined behavior with empty range

[delong.j at fb dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50529

--- Comment #5 from Jordan DeLong <delong.j at fb dot com> 2011-09-27 02:56:14 UTC ---
Nice.  Thanks!

[Bug libstdc++/50529] [C++0x] std::vector::erase invokes undefined behavior with empty range

[paolo at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50529

--- Comment #6 from paolo at gcc dot gnu.org <paolo at gcc dot gnu.org> 2011-09-30 20:47:17 UTC ---
Author: paolo
Date: Fri Sep 30 20:47:12 2011
New Revision: 179403

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=179403
Log:
2011-09-30  François Dumont  <fdumont@gcc.gnu.org>

    * include/debug/vector (vector<>::erase(iterator, iterator)): Check
    iterators equality using normal iterators.
    * include/debug/deque (deque<>::erase(iterator, iterator)): Likewise.

2011-09-30  Paolo Carlini  <paolo.carlini@oracle.com>

    PR libstdc++/50529
    * include/bits/vector.tcc (vector<>::erase(iterator, iterator)):
    Fix to do nothing if the range is empty.
    * include/bits/stl_bvector.h: Likewise.
    * include/bits/deque.tcc: Likewise.
    * include/debug/vector: Adjust.
    * include/debug/deque: Likewise.
    * testsuite/23_containers/vector/modifiers/erase/50529.cc: New.
    * testsuite/23_containers/deque/modifiers/erase/50529.cc: Likewise.
    * testsuite/23_containers/deque/modifiers/erase/3.cc: Adjust.

Added:
   
branches/gcc-4_6-branch/libstdc++-v3/testsuite/23_containers/deque/modifiers/erase/50529.cc
   
branches/gcc-4_6-branch/libstdc++-v3/testsuite/23_containers/vector/modifiers/erase/50529.cc
Modified:
    branches/gcc-4_6-branch/libstdc++-v3/ChangeLog
    branches/gcc-4_6-branch/libstdc++-v3/include/bits/deque.tcc
    branches/gcc-4_6-branch/libstdc++-v3/include/bits/stl_bvector.h
    branches/gcc-4_6-branch/libstdc++-v3/include/bits/vector.tcc
    branches/gcc-4_6-branch/libstdc++-v3/include/debug/deque
    branches/gcc-4_6-branch/libstdc++-v3/include/debug/vector
   
branches/gcc-4_6-branch/libstdc++-v3/testsuite/23_containers/deque/modifiers/erase/3.cc

[Bug libstdc++/50529] [C++0x] std::vector::erase invokes undefined behavior with empty range

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50529

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.7.0                       |4.6.2

--- Comment #7 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-09-30 20:48:32 UTC ---
Fixed in 4.6.2 too.