From: Nikita Popov <nikita.ppv@gmail.com>
Date: Thu, 4 Jul 2019 10:19:15 +0000 (+0200)
Subject: Preloading: Relax known type restrictions
X-Git-Tag: php-7.4.0alpha3~46
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=b250f89b92541e7c60310152cda6a50f0fa30225;p=php

Preloading: Relax known type restrictions

Check whether there is a parent/interface/trait method with the same
name and only then require the type to be known. This reduces the
number of cases where this triggers in practice a lot.
---

diff --git a/ext/opcache/ZendAccelerator.c b/ext/opcache/ZendAccelerator.c
index 41ea02b2c0..78260b9fe0 100644
--- a/ext/opcache/ZendAccelerator.c
+++ b/ext/opcache/ZendAccelerator.c
@@ -3350,7 +3350,7 @@ static void get_unresolved_initializer(zend_class_entry *ce, const char **kind,
 	} ZEND_HASH_FOREACH_END();
 }
 
-static zend_bool preload_all_types_known(zend_class_entry *ce);
+static zend_bool preload_needed_types_known(zend_class_entry *ce);
 static void get_unlinked_dependency(zend_class_entry *ce, const char **kind, const char **name) {
 	zend_class_entry *p;
 	*kind = "Unknown reason";
@@ -3401,7 +3401,7 @@ static void get_unlinked_dependency(zend_class_entry *ce, const char **kind, con
 		}
 	}
 
-	if (!preload_all_types_known(ce)) {
+	if (!preload_needed_types_known(ce)) {
 		*kind = "Unknown type dependencies";
 		return;
 	}
@@ -3529,17 +3529,58 @@ static zend_bool preload_is_type_known(zend_class_entry *ce, zend_type type) {
 	return known;
 }
 
-static zend_bool preload_all_types_known(zend_class_entry *ce) {
+static zend_bool preload_is_method_maybe_override(zend_class_entry *ce, zend_string *lcname) {
+	zend_class_entry *p;
+	if (ce->trait_aliases || ce->trait_precedences) {
+		return 1;
+	}
+
+	if (ce->parent_name) {
+		zend_string *key = zend_string_tolower(ce->parent_name);
+		p = zend_hash_find_ptr(EG(class_table), key);
+		zend_string_release(key);
+		if (zend_hash_exists(&p->function_table, lcname)) {
+			return 1;
+		}
+	}
+
+	if (ce->num_interfaces) {
+		uint32_t i;
+		for (i = 0; i < ce->num_interfaces; i++) {
+			zend_class_entry *p = zend_hash_find_ptr(EG(class_table), ce->interface_names[i].lc_name);
+			if (zend_hash_exists(&p->function_table, lcname)) {
+				return 1;
+			}
+		}
+	}
+
+	if (ce->num_traits) {
+		uint32_t i;
+		for (i = 0; i < ce->num_traits; i++) {
+			zend_class_entry *p = zend_hash_find_ptr(EG(class_table), ce->trait_names[i].lc_name);
+			if (zend_hash_exists(&p->function_table, lcname)) {
+				return 1;
+			}
+		}
+	}
+
+	return 0;
+}
+
+static zend_bool preload_needed_types_known(zend_class_entry *ce) {
 	zend_function *fptr;
-	ZEND_HASH_FOREACH_PTR(&ce->function_table, fptr) {
+	zend_string *lcname;
+	ZEND_HASH_FOREACH_STR_KEY_PTR(&ce->function_table, lcname, fptr) {
 		uint32_t i;
 		if (fptr->common.fn_flags & ZEND_ACC_HAS_RETURN_TYPE) {
-			if (!preload_is_type_known(ce, fptr->common.arg_info[-1].type)) {
+			if (!preload_is_type_known(ce, fptr->common.arg_info[-1].type) &&
+				preload_is_method_maybe_override(ce, lcname)) {
 				return 0;
 			}
 		}
 		for (i = 0; i < fptr->common.num_args; i++) {
-			if (!preload_is_type_known(ce, fptr->common.arg_info[i].type)) {
+			if (!preload_is_type_known(ce, fptr->common.arg_info[i].type) &&
+				preload_is_method_maybe_override(ce, lcname)) {
 				return 0;
 			}
 		}
@@ -3645,7 +3686,7 @@ static void preload_link(void)
 				 * know the types for covariant checks, but don't need them if we can ensure
 				 * compatibility through a simple string comparison. We could improve this using
 				 * a more general version of zend_can_early_bind(). */
-				if (!preload_all_types_known(ce)) {
+				if (!preload_needed_types_known(ce)) {
 					continue;
 				}
 
diff --git a/ext/opcache/tests/preload_variance.inc b/ext/opcache/tests/preload_variance.inc
index 09f057442c..7b2dd7b8ff 100644
--- a/ext/opcache/tests/preload_variance.inc
+++ b/ext/opcache/tests/preload_variance.inc
@@ -38,4 +38,6 @@ class H extends G {
 }
 
 // Early-binding preventer.
-class Z {}
+class Z {
+    public function method(X $a) {}
+}