gdb @7.7.1 completely useless

[trac-1948@…]

Hi, running MacPorts 2.3.2 (clean install) on Yosemite (clean install) with current Xcode (6.1).

I just compiled something with MacPorts' GCC 4.8 that worked fine on Mavericks, but now produces a segfault.

In order to debug the issue with MacPorts' gdb I did another build of the application in question with -O0 -g.

Then I tried to use gdb to obtain a stack backtrace of the crash in the application, however there is no usable output:

Program received signal SIGSEGV, Segmentation fault.
0x00007fff8fc64432 in ?? ()
(gdb) bt
#0  0x00007fff8fc64432 in ?? ()
#1  0x0000000100204bd9 in ?? ()
#2  0x00000001000a2690 in ?? ()
#3  0x00000000000060f1 in ?? ()
#4  0x000000010004cf78 in ?? ()
#5  0x00007fff5fbff328 in ?? ()
#6  0x0000000000000070 in ?? ()
#7  0x000000010004d15d in ?? ()
#8  0x00000001000a69c0 in ?? ()
#9  0x00000001000c9088 in ?? ()
#10 0x0000000000000000 in ?? ()

On Linux, this works, i.e. it gives me a backtrace, on Mac OS X with MacPorts' gdb this has never worked, I can't remember when I had a decent backtrace on OS X when developing with gcc and gdb on the command line. I'm not doing anything strange, so I can't quite understand what's going on...