[Bug c++/14065] New: Crash when loading symbols from C++11 / gcc 4.7 binary

[Bug c++/14065] New: Crash when loading symbols from C++11 / gcc 4.7 binary

[temporal at gmail dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14065

             Bug #: 14065
           Summary: Crash when loading symbols from C++11 / gcc 4.7 binary
           Product: gdb
           Version: 7.4
            Status: NEW
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned@sourceware.org
        ReportedBy: temporal@gmail.com
    Classification: Unclassified


Created attachment 6394
  --> http://sourceware.org/bugzilla/attachment.cgi?id=6394
Binary which causes gdb to crash on load (linux/x86_64)

I have a binary which makes fairly heavy use of C++11 features including
variadic templates, decltype, etc.  GDB segfaults on startup when "reading
symbols" from this binary.

I tried to narrow the problem down by progressively commenting out code until
the problem went away, but although commenting out enough code fixed the
problem, it didn't seem to correlate with any one piece of code.  My guess is
that GDB is running out of space in some fixed-size table.  My code perhaps
triggers the problem because I am using lots of deeply-nested templates leading
to very long symbol names.

So, I am just attaching the whole binary.  You don't have to run the binary,
just try to load it in gdb.  (The code can be found at
kentons-code.googlecode.com, but it's complicated to build, undocumented, and
generally incomprehensible.)

The problem occurs in Ubuntu's gdb 4.7 as well as built-from-source gdb 4.7.1.

Happy to provide more info if you can tell me what would be useful.  :)


$ uname -a
Linux megaman 3.2.0-24-generic #37-Ubuntu SMP Wed Apr 25 08:43:22 UTC 2012
x86_64 x86_64 x86_64 GNU/Linux

$ gcc-4.7 --version
gcc-4.7 (Ubuntu/Linaro 4.7.0-7ubuntu3) 4.7.0
Copyright (C) 2012 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ gdb --version
GNU gdb (Ubuntu/Linaro 7.4-2012.02-0ubuntu2) 7.4-2012.02
Copyright (C) 2012 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
For bug reporting instructions, please see:
<http://bugs.launchpad.net/gdb-linaro/>.

$ gdb crashgdb
GNU gdb (Ubuntu/Linaro 7.4-2012.02-0ubuntu2) 7.4-2012.02
Copyright (C) 2012 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
For bug reporting instructions, please see:
<http://bugs.launchpad.net/gdb-linaro/>...
Reading symbols from /home/kenton/code/crashgdb...Segmentation fault (core
dumped)

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[Bug c++/14065] Crash when loading symbols from C++11 / gcc 4.7 binary

[temporal at gmail dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14065

--- Comment #1 from Kenton Varda <temporal at gmail dot com> 2012-05-06 19:08:56 UTC ---
Ugh, when I said gdb 4.7/4.7.1 I of course meant gdb 7.4/7.4.1...

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[Bug c++/14065] Crash when loading symbols from C++11 / gcc 4.7 binary

[temporal at gmail dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14065

Kenton Varda <temporal at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |temporal at gmail dot com

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[Bug c++/14065] Crash when loading symbols from C++11 / gcc 4.7 binary

[tromey at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14065

Tom Tromey <tromey at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |tromey at redhat dot com

--- Comment #2 from Tom Tromey <tromey at redhat dot com> 2012-05-21 20:23:18 UTC ---
It's a bug in the demangler.  Valgrind shows:

barimba. echo
_ZN4modc6parser8sequenceINS_9astParser13LocatedParserINS0_9ParserRefINS2_UlRNS2_16TokenParserInputEE_EEEEEINS0_14OptionalParserINS2_18ListParserTemplateILNS_6tokens5Token4TypeE4EXadL_ZNSD_Ut_13parenthesizedEEEE6ParserINS4_INS0_6ParserIS5_NS_3ast10ExpressionEEEEEEEEENSA_INS4_INS2_22OneOfKeywordsToTParserINSJ_5StyleEEEEEEENS0_14SequenceParserIS5_INS0_18ExactElementParserIS5_EENSA_ISM_EEEEENS0_14RepeatedParserINS4_INS0_15TransformParserINSU_IS5_INS4_INSP_INSJ_10Annotation12RelationshipEEEEESX_EEENS2_UlNS2_3LocES12_ONS_5MaybeISK_EEE19_EEEEELb0EEEEEENSU_INS0_17ExtractParserTypeIT_E9InputTypeEINS0_8MaybeRefIS1F_E4TypeEDpNS1I_IT0_E4TypeEEEEOS1F_DpOS1L_
| valgrind --num-callers=50 ~/gnu/archer/build/libiberty/demangle 
==2911== Memcheck, a memory error detector
==2911== Copyright (C) 2002-2010, and GNU GPL'd, by Julian Seward et al.
==2911== Using Valgrind-3.6.1 and LibVEX; rerun with -h for copyright info
==2911== Command: /home/tromey/gnu/archer/build/libiberty/demangle
==2911== 
==2911== Conditional jump or move depends on uninitialised value(s)
==2911==    at 0x405925: d_find_pack (cp-demangle.c:3697)
==2911==    by 0x405A25: d_find_pack (cp-demangle.c:3731)
==2911==    by 0x405A25: d_find_pack (cp-demangle.c:3731)
==2911==    by 0x4059FD: d_find_pack (cp-demangle.c:3728)
==2911==    by 0x405A25: d_find_pack (cp-demangle.c:3731)
==2911==    by 0x4059FD: d_find_pack (cp-demangle.c:3728)
==2911==    by 0x405A25: d_find_pack (cp-demangle.c:3731)
==2911==    by 0x405A25: d_find_pack (cp-demangle.c:3731)
==2911==    by 0x4059FD: d_find_pack (cp-demangle.c:3728)
==2911==    by 0x4059FD: d_find_pack (cp-demangle.c:3728)
==2911==    by 0x4059FD: d_find_pack (cp-demangle.c:3728)
==2911==    by 0x405A25: d_find_pack (cp-demangle.c:3731)
==2911==    by 0x4059FD: d_find_pack (cp-demangle.c:3728)
==2911==    by 0x405A25: d_find_pack (cp-demangle.c:3731)
==2911==    by 0x4059FD: d_find_pack (cp-demangle.c:3728)
==2911==    by 0x4059FD: d_find_pack (cp-demangle.c:3728)
==2911==    by 0x405A25: d_find_pack (cp-demangle.c:3731)
==2911==    by 0x4059FD: d_find_pack (cp-demangle.c:3728)
==2911==    by 0x405A25: d_find_pack (cp-demangle.c:3731)
==2911==    by 0x4059FD: d_find_pack (cp-demangle.c:3728)
==2911==    by 0x405A25: d_find_pack (cp-demangle.c:3731)
==2911==    by 0x4059FD: d_find_pack (cp-demangle.c:3728)
==2911==    by 0x4059FD: d_find_pack (cp-demangle.c:3728)
==2911==    by 0x407D49: d_print_comp (cp-demangle.c:4659)
==2911==    by 0x406F53: d_print_comp (cp-demangle.c:4336)
==2911==    by 0x406FEC: d_print_comp (cp-demangle.c:4348)
==2911==    by 0x406F53: d_print_comp (cp-demangle.c:4336)
==2911==    by 0x406FEC: d_print_comp (cp-demangle.c:4348)
==2911==    by 0x406171: d_print_comp (cp-demangle.c:3947)
==2911==    by 0x406B0B: d_print_comp (cp-demangle.c:4206)
==2911==    by 0x405F8E: d_print_comp (cp-demangle.c:3894)
==2911==    by 0x4057A0: cplus_demangle_print_callback (cp-demangle.c:3611)
==2911==    by 0x408FE6: d_demangle_callback (cp-demangle.c:5240)
==2911==    by 0x40903B: d_demangle (cp-demangle.c:5261)
==2911==    by 0x4090A5: cplus_demangle_v3 (cp-demangle.c:5418)
==2911==    by 0x409601: main (cp-demangle.c:5667)
==2911==

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[Bug c++/14065] Crash when loading symbols from C++11 / gcc 4.7 binary

[tromey at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14065

Tom Tromey <tromey at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at sourceware    |tromey at redhat dot com
                   |dot org                     |

--- Comment #3 from Tom Tromey <tromey at redhat dot com> 2012-05-21 20:46:49 UTC ---
Submitted a patch.

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[Bug c++/14065] Crash when loading symbols from C++11 / gcc 4.7 binary

[tromey at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14065

Tom Tromey <tromey at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |7.5

--- Comment #4 from Tom Tromey <tromey at redhat dot com> 2012-05-22 13:57:17 UTC ---
Fixed.
But note if you are checking out from the gdb cvs repository,
you will have to wait until the file is sync'd from gcc svn.
The change you want is this one, from libiberty:

2012-05-22  Tom Tromey  <tromey@redhat.com>

        http://sourceware.org/bugzilla/show_bug.cgi?id=14065
        * testsuite/demangle-expected: Add regression test.
        * cp-demangle.c (d_find_pack): Return NULL for
        DEMANGLE_COMPONENT_UNNAMED_TYPE.

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[Bug c++/14065] Crash when loading symbols from C++11 / gcc 4.7 binary

[temporal at gmail dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14065

--- Comment #5 from Kenton Varda <temporal at gmail dot com> 2012-05-22 19:38:02 UTC ---
Thanks for the fix!

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