phpdbg8.1 -vrr does not print opcodes anymore

[tifeit]

Description

The following code:

<?php
echo 'hello world';

Resulted in this output:

$ phpdbg8.1 -vrr test.php
[Welcome to phpdbg, the interactive PHP debugger, v8.1.13]
To get help using phpdbg type "help" and press enter
[Please report bugs to <http://bugs.php.net/report.php>]
hello world

But I expected this output instead:

$ phpdbg8.0 -vrr test.php
[Welcome to phpdbg, the interactive PHP debugger, v8.0.26]
To get help using phpdbg type "help" and press enter
[Please report bugs to <http://bugs.php.net/report.php>]
[L3       0x7fe350a7c080 EXT_STMT                                                                               /home/mf/test.php]
[L3       0x7fe350a7c0a0 ECHO                    "hello world"                                                  /home/mf/test.php]
hello world
[L4       0x7fe350a7c0c0 RETURN<-1>              1                                                              /home/mf/test.php]

PHP Version

PHP 8.1.13

Operating System

Ubuntu 18.04

[nielsdos]

Looks like the condition for printing used to be

	if (ignore_flags ||
		(!(PHPDBG_G(flags) & PHPDBG_IS_QUIET) ||
		(PHPDBG_G(flags) & PHPDBG_IS_STEPPING) ||
		(PHPDBG_G(oplog)))) {

and now it is

if (ignore_flags || (!(PHPDBG_G(flags) & PHPDBG_IS_QUIET) && (PHPDBG_G(flags) & PHPDBG_IS_STEPPING))) {

It was changed in this PR: #7227

From the PR:

It also changes the default behaviour of printing oplines while stepping; we'll now only print instructions if quietness is off (quietness is by default on).

I'm not sure how to interpret this. This talks about printing oplines while stepping, not about printing oplines without stepping.

[nielsdos]

I think he meant that he didn't want to print oplines while stepping if quietness is on. However, then it sounds like it shouldn't have been changed for the case where we aren't stepping.
In abstract terms the condition right now is:
ignore_flags || (!quit && stepping)
To keep the old non-stepping behaviour, while respecting the stepping behaviour he described in the PR, we should change it to:

ignore_flags || (!quiet && stepping) || (!quiet && !stepping)

which simplifies to:

ignore_flags || !quiet

But I'm not sure whether that's desired.

[tifeit]

To highlight the rationale behind my request:

I use opcode dumping to compare what has changed between php versions. I dump the opcodes of the real execution context of complex code in the old version and then opcodes in the new version and inspect the diff.

This helps debug what has changed, for example, I'm now struggling to find the reason for 7% performance loss between php 8.1.12 and php 8.1.16 on our code.

So unfortunately running step debugging won't help me much in this case :( And if I understood correctly, this step debugging is the only option to get opcodes right now.

[nielsdos]

I understand that, thanks for explaining your rationale.
I'm not sure who to ask about the behaviour change. I'll look at this again tomorrow.

[nielsdos]

cc @devnexen @Girgias Could I please ask your opinion about the behavioural change (as explained in my previous messages)? I tagged you both because you handled some of my phpdbg PRs in the past. (Please let me know if it's not okay to tag you, then I won't do it in the future).

[Girgias]

I don't really use PHPDBG nor really understand how it works, @bwoebi is probably a better person to ask.

But that behavioural change looks kinda fishy I do agree, not sure how to interpret it either.