Improve the optimizer's check if a function is a prototype or not

Currently, a function is considered a prototype if the function is not
marked as final. However, a class marked as final or an anonymous class
also make it impossible for a function to be overridden. Therefore, we
know in these 2 cases too that the function is not a prototype.
This allows the type inference algorithm to determine some types more
precisely, and can allow for more optimizations of the instructions.
Additionally, place some computation of the flags in their respective
blocks as a micro-optimization.

Author: nielsdos

Zend/Optimizer/zend_optimizer.c

@@ -891,16 +891,23 @@ zend_function *zend_optimizer_get_called_func(
 					&op_array->scope->function_table, method_name);
 				if (fbc) {
 					bool is_private = (fbc->common.fn_flags & ZEND_ACC_PRIVATE) != 0;
-					bool is_final = (fbc->common.fn_flags & ZEND_ACC_FINAL) != 0;
-					bool same_scope = fbc->common.scope == op_array->scope;
 					if (is_private) {
 						/* Only use private method if in the same scope. We can't even use it
 						 * as a prototype, as it may be overridden with changed signature. */
+						bool same_scope = fbc->common.scope == op_array->scope;
 						return same_scope ? fbc : NULL;
 					}
 					/* If the method is non-final, it may be overridden,
 					 * but only with a compatible method signature. */
-					*is_prototype = !is_final;
+					/* We know it isn't a prototype if it can be overridden.
+					 * A method cannot be overridden if the class or method is final, or
+					 * if it's an anonymous class. */
+					bool can_be_overridden = (fbc->common.fn_flags & ZEND_ACC_FINAL) == 0 &&
+											 (fbc->common.scope->ce_flags & ZEND_ACC_FINAL) == 0 &&
+											 (fbc->common.scope->ce_flags & ZEND_ACC_ANON_CLASS) == 0;
+					if (can_be_overridden) {
+						*is_prototype = true;
+					}
 					return fbc;
 				}
 			}

ext/opcache/tests/opt/type_inference_final_or_anonymous_class.phpt

@@ -0,0 +1,70 @@
+--TEST--
+Type inference test with final or anonymous class
+--INI--
+opcache.enable=1
+opcache.enable_cli=1
+opcache.optimization_level=-1
+opcache.opt_debug_level=0x20000
+opcache.preload=
+--EXTENSIONS--
+opcache
+--FILE--
+<?php
+
+final class Test {
+    public function getInt(): int {
+        return 42;
+    }
+    public function getInt2(): int {
+        return $this->getInt();
+    }
+}
+
+$anon = new class {
+    public function getInt(): int {
+        return 42;
+    }
+    public function getInt2(): int {
+        return $this->getInt();
+    }
+};
+
+?>
+--EXPECTF--
+$_main:
+     ; (lines=5, args=0, vars=1, tmps=2)
+     ; (after optimizer)
+     ; %s
+0000 V2 = DECLARE_ANON_CLASS string("class@anonymous")
+0001 V1 = NEW 0 V2
+0002 DO_FCALL
+0003 ASSIGN CV0($anon) V1
+0004 RETURN int(1)
+LIVE RANGES:
+     1: 0002 - 0003 (new)
+
+Test::getInt:
+     ; (lines=1, args=0, vars=0, tmps=0)
+     ; (after optimizer)
+     ; %s
+0000 RETURN int(42)
+
+Test::getInt2:
+     ; (lines=2, args=0, vars=0, tmps=1)
+     ; (after optimizer)
+     ; %s
+0000 V0 = QM_ASSIGN int(42)
+0001 RETURN V0
+
+class@anonymous::getInt:
+     ; (lines=1, args=0, vars=0, tmps=0)
+     ; (after optimizer)
+     ; %s
+0000 RETURN int(42)
+
+class@anonymous::getInt2:
+     ; (lines=2, args=0, vars=0, tmps=1)
+     ; (after optimizer)
+     ; %s
+0000 V0 = QM_ASSIGN int(42)
+0001 RETURN V0