[Bug libstdc++/53630] New: C+11 regex compiler produces SIGSEGV

[Bug libstdc++/53630] New: C+11 regex compiler produces SIGSEGV

[bisqwit at iki dot fi]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53630

             Bug #: 53630
           Summary: C+11 regex compiler produces SIGSEGV
    Classification: Unclassified
           Product: gcc
           Version: 4.7.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: bisqwit@iki.fi


This simple code produces a segmentation fault. Tested in GCC 4.7.0, GCC 4.6.3,
and Clang 3.1 (where the latter uses libstdc++ from GCC 4.7).

#include <regex>

int main()
{
    std::regex r("(go |)((n(orth|))|(s(outh|))|(w(est|))|(e(ast|)))",
std::regex::extended);
    return 0;
}

Omitting the std::regex::extended option does not make a difference.

Replacing all of the "|)" with ")" makes it compile, but obviously with a
completely different expression. As of now, libstdc++ does not yet support the
'?' operator, so the expression cannot be rewritten as "(go
)?((n(orth)?)|(s(outh)?)|(w(est)?)|(e(ast)?))". There is also no non-capturing
grouping operator, so writing e.g. (n(?:orth|)) is not an option.

A minimal regexp that duplicates the crash is: "((a(b|))|x)". Simple
reorderings such as "((a(|b))|x)" or "(x|(a(|b)))" do not make a difference.

GDB backtrace below:

(gdb) bt
#0  0x00007ffff732cdbd in malloc_consolidate (av=0x7ffff7639e60) at
malloc.c:5169
#1  0x00007ffff732f2a4 in _int_malloc (av=0x7ffff7639e60, bytes=1280) at
malloc.c:4373
#2  0x00007ffff7331960 in *__GI___libc_malloc (bytes=1280) at malloc.c:3660
#3  0x00007ffff7b39e6d in operator new(unsigned long) () from
/usr/lib/x86_64-linux-gnu/libstdc++.so.6
#4  0x0000000000404ce4 in
__gnu_cxx::new_allocator<std::__regex::_State>::allocate (this=0x7fffffffe980,
__n=16)
    at
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.7/../../../../include/c++/4.7/ext/new_allocator.h:94
#5  0x00000000004046b0 in std::_Vector_base<std::__regex::_State,
std::allocator<std::__regex::_State> >::_M_allocate (this=0x7fffffffe980,
__n=16)
    at
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.7/../../../../include/c++/4.7/bits/stl_vector.h:169
#6  0x0000000000404338 in
_ZNSt6vectorINSt7__regex6_StateESaIS1_EE19_M_emplace_back_auxIJS1_EEEvDpOT_
(this=0x7fffffffe980, __args=0x7fffffffe010)
    at
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.7/../../../../include/c++/4.7/bits/vector.tcc:402
#7  0x0000000000404270 in
_ZNSt6vectorINSt7__regex6_StateESaIS1_EE12emplace_backIJS1_EEEvDpOT_
(this=0x7fffffffe980, __args=0x7fffffffe010)
    at
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.7/../../../../include/c++/4.7/bits/vector.tcc:102
#8  0x0000000000403690 in std::vector<std::__regex::_State,
std::allocator<std::__regex::_State> >::push_back(std::__regex::_State&&) (
    this=0x7fffffffe980, __x=0x7fffffffe010) at
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.7/../../../../include/c++/4.7/bits/stl_vector.h:900
#9  0x0000000000403052 in
std::__regex::_Nfa::_M_insert_subexpr_begin(std::function<void
(std::__regex::_PatternCursor const&, std::__regex::_Results&)> const&)
(this=0x7fffffffe978, __t=...) at
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.7/../../../../include/c++/4.7/bits/regex_nfa.h:312
#10 0x000000000040848f in std::__regex::_Compiler<char const*,
std::regex_traits<char> >::_M_atom (this=0x7fffffffe928)
    at
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.7/../../../../include/c++/4.7/bits/regex_compiler.h:943
#11 0x0000000000407b98 in std::__regex::_Compiler<char const*,
std::regex_traits<char> >::_M_term (this=0x7fffffffe928)
    at
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.7/../../../../include/c++/4.7/bits/regex_compiler.h:793
#12 0x0000000000405be9 in std::__regex::_Compiler<char const*,
std::regex_traits<char> >::_M_alternative (this=0x7fffffffe928)
    at
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.7/../../../../include/c++/4.7/bits/regex_compiler.h:771
#13 0x0000000000403119 in std::__regex::_Compiler<char const*,
std::regex_traits<char> >::_M_disjunction (this=0x7fffffffe928)
    at
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.7/../../../../include/c++/4.7/bits/regex_compiler.h:756
#14 0x00000000004084d5 in std::__regex::_Compiler<char const*,
std::regex_traits<char> >::_M_atom (this=0x7fffffffe928)
    at
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.7/../../../../include/c++/4.7/bits/regex_compiler.h:945
#15 0x0000000000407b98 in std::__regex::_Compiler<char const*,
std::regex_traits<char> >::_M_term (this=0x7fffffffe928)
    at
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.7/../../../../include/c++/4.7/bits/regex_compiler.h:793
#16 0x0000000000405be9 in std::__regex::_Compiler<char const*,
std::regex_traits<char> >::_M_alternative (this=0x7fffffffe928)
    at
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.7/../../../../include/c++/4.7/bits/regex_compiler.h:771
#17 0x0000000000405c2f in std::__regex::_Compiler<char const*,
std::regex_traits<char> >::_M_alternative (this=0x7fffffffe928)
    at
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.7/../../../../include/c++/4.7/bits/regex_compiler.h:774
#18 0x0000000000403119 in std::__regex::_Compiler<char const*,
std::regex_traits<char> >::_M_disjunction (this=0x7fffffffe928)
    at
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.7/../../../../include/c++/4.7/bits/regex_compiler.h:756
#19 0x0000000000402cae in std::__regex::_Compiler<char const*,
std::regex_traits<char> >::_Compiler (this=0x7fffffffe928, 
    __b=@0x7fffffffea70: 0x40cb10 "(go
|)((n(orth|))|(s(outh|))|(w(est|))|(e(ast|)))", __e=@0x7fffffffea50: 0x40cb41
"", __traits=..., __flags=64)
    at
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.7/../../../../include/c++/4.7/bits/regex_compiler.h:727
#20 0x0000000000401f25 in std::__regex::_Compiler<char const*,
std::regex_traits<char> >::_Compiler (this=0x7fffffffe928, 
    __b=@0x7fffffffea70: 0x40cb10 "(go
|)((n(orth|))|(s(outh|))|(w(est|))|(e(ast|)))", __e=@0x7fffffffea50: 0x40cb41
"", __traits=..., __flags=64)
    at
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.7/../../../../include/c++/4.7/bits/regex_compiler.h:735
#21 0x0000000000401d80 in std::__regex::__compile<char const*,
std::regex_traits<char> > (
    __b=@0x7fffffffea70: 0x40cb10 "(go
|)((n(orth|))|(s(outh|))|(w(est|))|(e(ast|)))", __e=@0x7fffffffea50: 0x40cb41
"", __t=..., __f=64)
    at
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.7/../../../../include/c++/4.7/bits/regex_compiler.h:1102
#22 0x0000000000401cc1 in std::basic_regex<char, std::regex_traits<char>
>::basic_regex (this=0x7fffffffeac8, 
    __p=0x40cb10 "(go |)((n(orth|))|(s(outh|))|(w(est|))|(e(ast|)))", __f=64)
    at
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.7/../../../../include/c++/4.7/bits/regex.h:405
#23 0x0000000000401a23 in std::basic_regex<char, std::regex_traits<char>
>::basic_regex (this=0x7fffffffeac8, 
    __p=0x40cb10 "(go |)((n(orth|))|(s(outh|))|(w(est|))|(e(ast|)))", __f=64)
    at
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.7/../../../../include/c++/4.7/bits/regex.h:407
#24 0x0000000000401915 in main () at test.cc:5


I also tested this on boost::regex, but boost::regex does not crash. This bug
may be related to PR52719.

[Bug libstdc++/53630] C+11 regex compiler produces SIGSEGV

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53630

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-06-11 08:29:50 UTC ---
Documented as missing in
http://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html#status.iso.2011

The whole of Clause 28 is partially supported or not supported at all.

i.e. <regex> DOESN'T WORK!

There's really no point reporting bugs against unimplemented functionality.

[Bug libstdc++/53630] C+11 regex compiler produces SIGSEGV

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53630

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |DUPLICATE

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-06-11 08:36:29 UTC ---
.

*** This bug has been marked as a duplicate of bug 53631 ***