This is a new transparent technology that eliminates overhead of PHP class inheritance.
PHP classes are compiled and cached (by opcahce) separately, however their "linking" was done at run-time - on each request. The process of "linking" may involve a number of compatibility checks and borrowing methods/properties/constants form parent and traits. This takes significant time, but the result is the same on each request.
Inheritance Cache performs "linking" for unique set of all the depending classes (parent, interfaces, traits, property types, method types involved into compatibility checks) once and stores result in opcache shared memory. As a part of the this patch, I removed limitations for immutable classes (unresolved constants, typed properties and covariant type checks). So now all classes stored in opcache are "immutable". They may be lazily loaded into process memory, if necessary, but this usually occurs just once (on first linking).
The patch shows 8% improvement on Symphony "Hello World" app.
We should also set retval_ref when de-indirecting. Otherwise the
retval_ref != retval_ptr comparison below may incorrect assume
that we're returning a reference.
I don't have a reliable reproducer for this issue, but it sometimes
appears in certain configurations in arrow_functions/007.phpt in
conjunction with other changes.
We're starting to see a mix between uses of zend_bool and bool.
Replace all usages with the standard bool type everywhere.
Of course, zend_bool is retained as an alias.
This restricts allowed usage of $GLOBALS, with the effect that
plain PHP arrays can no longer contain INDIRECT elements.
RFC: https://wiki.php.net/rfc/restrict_globals_usage
Closes GH-6487.
If we have an undefined variable and null is not accepted by the
return type, we want to throw just the undef var error.
In this case this lead to an infinite loop, because we overwrite
the exception opline in SAVE_OPLINE and it does not get reset
when chaining into a previous exception. Add an assertiong to
catch this case earlier.
ZEND_HANDLE_EXCEPTION might call zend_observer_fcall_end() even if exception is cought by function. The fix moved zend_observer_fcall_end() into a right place and remove OBSERVER sepecialization for ZEND_HANDLE_EXCEPTION handler.
Voidification of Zend API which always succeeded
Use bool argument types instead of int for boolean arguments
Use bool return type for functions which return true/false (1/0)
Use zend_result return type for functions which return SUCCESS/FAILURE as they don't follow normal boolean semantics
Closes GH-6002
