gdb symbol problem

gistfile1.txt

➜  php-src git:(PHP-5.4) ✗ gdb sapi/cli/php
GNU gdb 6.3.50-20050815 (Apple version gdb-1705) (Fri Jul  1 10:50:06 UTC 2011)
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This GDB was configured as "x86_64-apple-darwin"...Reading symbols for shared libraries ....... done

(gdb) b gc_zval_possible_root
Breakpoint 1 at 0x10062ddc0: file zend_gc.c, line 132.
(gdb) r -r '<?php $a=0; $a=null; gc_collect_cycles(); ?>';
Starting program: /Users/reeze/Opensource/php-src/sapi/cli/php -r '<?php $a=0; $a=null; gc_collect_cycles(); ?>';
Reading symbols for shared libraries ++++++.......................... done

Breakpoint 1, gc_zval_possible_root (zv=0x100f96b58, tsrm_ls=0x1010009b0) at zend_gc.c:132
132		if (UNEXPECTED(GC_G(free_list) != NULL &&
(gdb) printzv zv
No symbol "zend_executor_globals" in current context.
(gdb) bt
#0  gc_zval_possible_root (zv=0x100f96b58, tsrm_ls=0x1010009b0) at zend_gc.c:132
#1  0x00000001005cf355 in _zval_ptr_dtor (zval_ptr=0x7fff5fbfe820, __zend_filename=0x100bf30f8 "/Users/reeze/Opensource/php-src/main/php_variables.c", __zend_lineno=530) at zend_gc.h:183
#2  0x000000010052d69b in php_build_argv (s=0x0, track_vars_array=0x0, tsrm_ls=0x1010009b0) at php_variables.c:530
#3  0x000000010052dee6 in php_hash_environment (tsrm_ls=0x1010009b0) at php_variables.c:644
#4  0x000000010050d206 in php_request_startup (tsrm_ls=0x1010009b0) at main.c:1568
#5  0x00000001007fd5df in do_cli (argc=3, argv=0x7fff5fbff5a0, tsrm_ls=0x1010009b0) at php_cli.c:959
#6  0x00000001007ff8ae in main (argc=3, argv=0x7fff5fbff5a0) at php_cli.c:1361
(gdb) printzv zv
[0x100f96b58] (refcount=1) array(1): {
    0 => [0x100f96c80] (refcount=1) string(1): "-"
  }
(gdb)