This is the mail archive of the gdb-patches@sourceware.org mailing list for the GDB project.
Index Nav: | [Date Index] [Subject Index] [Author Index] [Thread Index] | |
---|---|---|
Message Nav: | [Date Prev] [Date Next] | [Thread Prev] [Thread Next] |
Other format: | [Raw text] |
Thoughts ? Sami
Hello,
since one of this year's C++ namespace search related changes, GDB will go into an endless recursion and crash due to stack overflow when looking up symbols in the presence of a cycle in the "using" directive graph.
For example, with the following test:
namespace A { namespace B { using namespace ::A; } using namespace B; }
using namespace A;
class test { }; test x;
int main() { }
I'm seeing:
(gdb) start Temporary breakpoint 1 at 0x80000626: file xxx.cc, line 16. Starting program: /home7/uweigand/fsf/gdb-head-build/gdb/a.out
Temporary breakpoint 1, main () at xxx.cc:16 16 int main() { } (gdb) print x[0] Segmentation fault (core dumped)
(The lookup that happens here is for operator[] -- which doesn't exist, but in trying to find it we run into the endless loop.)
This is particularly annyoing as the SLES10 system library on s390 and ppc contains exactly this construct in the header /usr/include/c++/4.1.2/bits/localefwd.h:
namespace std { namespace __gnu_cxx_ldbl128 { using namespace ::std; } using namespace __gnu_cxx_ldbl128 __attribute__((__strong__));
which means it is present in just about every C++ executable.
(This seems specific to the SLES backport of the long-double compatibility support. The upstream implementation does not have this cycle ... But still, the general construct looks to be valid C++ as far as I can tell.)
Any thoughts how to fix this?
Bye, Ulrich
Attachment:
namespace-loop.patch
Description: Text document
Index Nav: | [Date Index] [Subject Index] [Author Index] [Thread Index] | |
---|---|---|
Message Nav: | [Date Prev] [Date Next] | [Thread Prev] [Thread Next] |