Re: [ZEND-ENGINE-CVS] cvs: ZendEngine2(PHP_5_3) / zend.c zend_execute_API.c zend_vm_def.h zend_vm_execute.h php-src NEWS

On Fri, 11 Apr 2008, Dmitry Stogov wrote:

> dmitry		Fri Apr 11 09:43:31 2008 UTC
> 
>   Modified files:              (Branch: PHP_5_3)
>     /php-src	NEWS 
>     /ZendEngine2	zend.c zend_execute_API.c zend_vm_def.h 
>                 	zend_vm_execute.h 
>   Log:
>   Optimized ZEND_RETURN opcode to not allocate and copy return value if it is not
>   used.

Hmm, I'm not too happy with this, as it breaks some functionality in 
Xdebug. Xdebug allows you to create a function trace, including all 
return values. For example the following script:

<?php
function foo() { return 42; }
foo();
echo foo();
?>

Gave a function trace like
(with php -d xdebug.auto_trace=1 -dxdebug.collect_return=1 test-ft.php):

TRACE START [2008-04-11 10:29:49]
    0.0002     650528   -> {main}() /tmp/test-ft.php:0
    0.0003     650840     -> foo() /tmp/test-ft.php:8
                           >=> 42
    0.0004     650840     -> foo() /tmp/test-ft.php:9
                           >=> 42
                         >=> 1
    0.0013      54536
TRACE END   [2008-04-11 10:29:49]

However, with this change, I only get:

TRACE START [2008-04-11 10:32:11]
    0.2148     652336   -> {main}() /tmp/test-ft.php:0
    0.2907     652648     -> foo() /tmp/test-ft.php:8
    0.3178     652648     -> foo() /tmp/test-ft.php:9
                           >=> 42
    0.4802      56344
TRACE END   [2008-04-11 10:32:12]


Is it still possible to get the return values of the functions that are 
*not* used? I currently check if EG(return_value_ptr_ptr) and 
*EG(return_value_ptr_ptr) are not NULL to see if there is a return 
value, and now (of course) they are empty (null pointer).

regards,
Derick

-- 
Derick Rethans
http://derickrethans.nl | http://ezcomponents.org | http://xdebug.org