Add ZEND_VM_KIND constant

[derickr]

Per request/suggestion from @sebastianbergmann

[arnaud-lb]

I think it would be fine to just expose ZEND_VM_KIND as a string (HYBRID|TAILCALL|CALL), and to remove the ZEND_VM_KIND_ constants.

[kallesommernielsen]

I think it would be fine to just expose ZEND_VM_KIND as a string (HYBRID|TAILCALL|CALL), and to remove the ZEND_VM_KIND_ constants.

While I tend to agree with this because it's a bit of a niche use case. The current proposal does make for a nicer API for the end user given we didn't go as far as to make it an enumeration.

TL;DR I think the current PR is just fine for what we are looking to achieve

[TimWolla]

The current proposal does make for a nicer API for the end user given we didn't go as far as to make it an enumeration.

I disagree. The other constants are not really properly discoverable either and with the "random integer value" they are just fancy strings. So we might as well use a string directly.

[edorian]

No RM objections for this to go into 8.5 if desired.

No technical review performed.

[derickr]

I am happy to expose it as a string, but then we can't use the stub like this, as the strings aren't part of PHP yet. Will have a look at this again then.

[arnaud-lb]

Unfortunately this breaks zend_vm_gen.php as the script defines ZEND_VM_KIND too. I suggest renaming ZEND_VM_KIND to ZEND_VM_MAIN_KIND or ZEND_VM_GEN_KIND in that script.

Looks good to me otherwise!