Fix circumvented added hooks in JIT

[iluuu1994]

The following code poses a problem in the JIT:

class A {
    public $prop = 1;
}

class B extends A {
    public $prop = 1 {
        get => parent::$prop::get() * 2;
    }
}

function test(A $a) {
    var_dump($a->prop);
}

test(new B);

The JIT would assume A::$prop in test() could be accessed directly through OBJ_PROP_NUM(). However, since child classes can add new hooks to existing properties, this assumption no longer holds.

To avoid introducing more JIT checks, a hooked property that overrides a unhooked property now results in a separate zval slot that is used instead of the parent slot. This causes the JIT to pick the slow path due to an IS_UNDEF value in the parent slot.

zend_class_entry.properties_info_table poses a problem in that zend_get_property_info_for_slot() and friends will be called using the child slot, which does not store its property info, since the parent slot already does. In this case, zend_get_property_info_for_slot() now provides a fallback that will iterate all property infos to find the correct one.

This also uncovered a bug (see Zend/tests/property_hooks/dump.phpt) where the default value of a parent property would accidentally be inherited by the child property.

Fixes GH-17376

[iluuu1994]

I have no clue what this Windows failure is about. 😞 I can't reproduce on Linux with asan/msan/valgrind, w/wo opcache, nts/zts, etc. @cmb69 Can you help? I don't have a VM...

[cmb69]

It's a JIT issue. Running ext\random\tests\02_engine\all_serialize_user.phpt under ASan/tracing JIT:

Random\Engine\Test\TestCountingEngine32
=================================================================
==13488==ERROR: AddressSanitizer: access-violation on unknown address 0x000000000014 (pc 0x7ffce98a8fa2 bp 0x0089ff7fc6b0 sp 0x0089ff7fadb0 T0)
==13488==The signal is caused by a READ memory access.
==13488==Hint: address points to the zero page.
    #0 0x7ffce98a8fa1 in verify_readonly_and_avis C:\php-sdk\phpdev\vs17\x64\php-src\ext\opcache\jit\zend_jit_helpers.c:2716
    #1 0x7ffce989b658 in zend_jit_post_inc_typed_prop C:\php-sdk\phpdev\vs17\x64\php-src\ext\opcache\jit\zend_jit_helpers.c:2976
    #2 0x200008000e61  (<unknown module>)
    #3 0x000000007f12  (<unknown module>)
    #4 0x000000000000  (<unknown module>)
    #5 0x000000007f13  (<unknown module>)
    #6 0x1205678a1cd7  (<unknown module>)
    #7 0x1205678a1c7f  (<unknown module>)
    #8 0x11f9678c0877  (<unknown module>)
    #9 0x11f9678c073f  (<unknown module>)
    #10 0x11f9678c0877  (<unknown module>)
    #11 0x002700000027  (<unknown module>)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: access-violation C:\php-sdk\phpdev\vs17\x64\php-src\ext\opcache\jit\zend_jit_helpers.c:2716 in verify_readonly_and_avis
==13488==ABORTING

Does that help?

[iluuu1994]

Thank you very much! It might, I'll have a look very soon.

[cmb69]

Looks good. :)

[iluuu1994]

@cmb69 Indeed, it did help 😊 Thanks again!