$ /usr/local/lib/php5/bin/php -v
PHP 5.3.0alpha3-dev (cli) (built: Dec  3 2008 11:35:21)
Copyright (c) 1997-2008 The PHP Group
Zend Engine v2.3.0, Copyright (c) 1998-2008 Zend Technologies
    with Xdebug v2.1.0-dev, Copyright (c) 2002-2008, by Derick Rethans

(gdb) run -a
Starting program: /usr/local/lib/php5/bin/php -a
[Thread debugging using libthread_db enabled]
[New Thread 0xb724c6d0 (LWP 5997)]
Interactive shell

php > require_once('foo.php');

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0xb724c6d0 (LWP 5997)]
0xb7043743 in add_stack_frame (zdata=0x89b1aa0, op_array=0x8982804, type=2) at /root/xdebug-2.1/xdebug.c:1120
1120    /root/xdebug-2.1/xdebug.c: No such file or directory.
        in /root/xdebug-2.1/xdebug.c
(gdb) bt
#0  0xb7043743 in add_stack_frame (zdata=0x89b1aa0, op_array=0x8982804, type=2) at /root/xdebug-2.1/xdebug.c:1120
#1  0xb7044d05 in xdebug_execute (op_array=0x8982804) at /root/xdebug-2.1/xdebug.c:1560
#2  0x083289e6 in execute_new_code () at /root/php-5.3/Zend/zend_execute_API.c:1253
#3  0x08308919 in zendparse () at /root/php-5.3/Zend/zend_language_parser.y:159
#4  0x0830987d in compile_file (file_handle=0xbfc05040, type=8) at Zend/zend_language_scanner.l:345
#5  0x081c9275 in phar_compile_file (file_handle=0xbfc05040, type=8) at /root/php-5.3/ext/phar/phar.c:3349
#6  0xb7047932 in xdebug_compile_file (file_handle=0xbfc05040, type=8) at /root/xdebug-2.1/xdebug.c:2535
#7  0x08358993 in ZEND_INCLUDE_OR_EVAL_SPEC_CONST_HANDLER (execute_data=0x89b1aa0) at /root/php-5.3/Zend/zend_vm_execute.h:1861
#8  0x08355de9 in execute (op_array=0x89822f8) at /root/php-5.3/Zend/zend_vm_execute.h:104
#9  0xb7044eca in xdebug_execute (op_array=0x89822f8) at /root/xdebug-2.1/xdebug.c:1606
#10 0x083289e6 in execute_new_code () at /root/php-5.3/Zend/zend_execute_API.c:1253
#11 0x08308919 in zendparse () at /root/php-5.3/Zend/zend_language_parser.y:159
#12 0x0830987d in compile_file (file_handle=0xbfc066f0, type=8) at Zend/zend_language_scanner.l:345
#13 0x081c9275 in phar_compile_file (file_handle=0xbfc066f0, type=8) at /root/php-5.3/ext/phar/phar.c:3349
#14 0xb7047932 in xdebug_compile_file (file_handle=0xbfc066f0, type=8) at /root/xdebug-2.1/xdebug.c:2535
#15 0x08358993 in ZEND_INCLUDE_OR_EVAL_SPEC_CONST_HANDLER (execute_data=0x89b1a40) at /root/php-5.3/Zend/zend_vm_execute.h:1861
#16 0x08355de9 in execute (op_array=0x8981d78) at /root/php-5.3/Zend/zend_vm_execute.h:104
#17 0xb7044eca in xdebug_execute (op_array=0x8981d78) at /root/xdebug-2.1/xdebug.c:1606
#18 0x08329cef in zend_eval_string (str=0x8980d70 "require_once('foo.php');\n", retval_ptr=0x0, string_name=0x87d408d "php shell code")
    at /root/php-5.3/Zend/zend_execute_API.c:1150
#19 0x083bf642 in main (argc=2, argv=0xbfc06be4) at /root/php-5.3/sapi/cli/php_cli.c:1106
(gdb)