Core dumped with specific jit config

[YuanchengJiang]

Description

The following code:

<?php
//any php file

Resulted in this output:

/php-src/ext/opcache/jit/zend_jit.c:3199: int zend_jit_script(zend_script *): Assertion `0' failed.
Aborted (core dumped)

To reproduce:

-d "extension_dir=/php-src/modules/" -d "zend_extension=/php-src/modules/opcache.so" -d "opcache.enable=1" -d "opcache.enable_cli=1" -d "opcache.jit=1245"

PHP Version

PHP 8.4.0-dev

Operating System

ubuntu 22.04

[YuanchengJiang]

when -d "opcache.jit=1044":

/php-src/ext/opcache/jit/zend_jit.c:3119: int zend_jit_op_array(zend_op_array *, zend_script *): Assertion `0' failed.
Aborted (core dumped)

[cmb69]

Given the relatively high amount of bug reports regarding advanced JIT configuration (besides this ticket also #15821, #15662, #15657, and maybe more), I wonder whether we should explicitly document these advanced JIT settings as being experimental?

By the way, the documentation on Trigger 4 says it would be "currently unused", but is documented in zend_jit.h says compile functions with "@jit" tag in doc-comments. Maybe we should update the documentation, telling what it is supposed to do, but that this is not yet implemented. I wonder though, whether T=4 is treated as T=0 or what actually happens.

[YuanchengJiang]

@cmb69 good point, I am also conservative when reporting such bugs, let me know if it is a global document problem or it is expected or if we don't care about such weird JIT errors

[cmb69]

Maybe @dstogov and/or @iluuu1994 can comment about the usage of advanced JIT configuration (i.e. opcache.jit anything other than on, off, function or tracing).

[iluuu1994]

By the way, the documentation on Trigger 4 says it would be "currently unused", but is documented in zend_jit.h says compile functions with "@jit" tag in doc-comments.

I think this was never implemented. I'm not sure if there are any plans to do that, and if there would even be a benefit to it.

Regarding config, IMO it would make sense to simplify the JIT settings. It's doubtful many people are qualified to pick sensible settings, as they are quite cryptic for non-JIT specialists. Fewer special settings should reduce bugs and simplify the code.