Don't use separate static variables in inherited methods

RFC: https://wiki.php.net/rfc/static_variable_inheritance

Closes GH-6719.

Fix static variable behavior with inheritance

When a method is inherited, the static variables will now always
use the initial values, rather than the values at the time of
inheritan

Fix static variable behavior with inheritance

When a method is inherited, the static variables will now always
use the initial values, rather than the values at the time of
inheritance. As such, behavior no longer depends on whether
inheritance happens before or after a method has been called.

This is implemented by always keeping static_variables as the
original values, and static_variables_ptr as the modified copy.

Closes GH-6705.

show more ...

Added Inheritance Cache.

This is a new transparent technology that eliminates overhead of PHP class inheritance.

PHP classes are compiled and cached (by opcahce) separately, howeve

Added Inheritance Cache.

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.

show more ...