[WIP] accessor optimization

[c9s]

Implement property getter optimization to make getter methods 2 times faster

Optimization Targets

Simple getters

class Foo {
    protected $value;
    public function getValue() {
        return $this->value;
    }
}

Const accessor

class Foo {
    public function getTemplate() {
        return "base.html";
    }
}

Simple setters

class Foo {
    protected $template;
    public function setTemplate($template) {
        $this->template = $template;
    }
}

Changes

• Added accessor struct to op_array struct for saving accessor
  information.
• Added accessor checking in pass_two() for getter functions.
• Added quick property getter in INIT_METHOD_CALL op handler

Benchmark Result

Getter Method Only

https://gist.github.com/8cd230a5601cbe38439661adf3caca0d

Without getter optimization (3 runs):
151.0169506073ms

With getter optimization (3 runs)
39.201021194458ms

Affect

Other Microbench result: https://gist.github.com/c9s/0273ac21631562724cabf86c42e86e32

[staabm]

Would be great to see numbers in a real app, e.g. Wordpress

[dstogov]

It's not great to extend all op_arrays with rarely used fields for getters only.

[c9s]

I am not quiet sure if the code below makes sense, however it fixes the tests:

                        if (nextop->result_type == IS_VAR) {
                            ZVAL_DEREF(retval);
                            ZVAL_COPY(EX_VAR(nextop->result.var), retval);
                            assigned_result = 1;
                        }

[c9s]

I thought copying value should be done by the code below?

ZVAL_COPY_VALUE(EX_VAR(nextop->result.var), retval);
if (UNEXPECTED(Z_OPT_COPYABLE_P(EX_VAR(nextop->result.var)))) {
    zval_copy_ctor_func(EX_VAR(nextop->result.var));
}

[c9s]

Tests are passing now. I will clean up and refine them tomorrow.

[c9s]

will send this PR later when func info is ready is the core.