From: Nikita Popov <nikic@php.net>
Date: Sat, 30 Apr 2016 10:27:36 +0000 (+0200)
Subject: Mark all $php_errormsg as refs to inhibit optimization
X-Git-Tag: php-7.1.0alpha1~231
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=0615c59a4fef83e0d90384c5f5664e72874c680c;p=php

Mark all $php_errormsg as refs to inhibit optimization
---

diff --git a/Zend/tests/php_errormsg_misoptimization.phpt b/Zend/tests/php_errormsg_misoptimization.phpt
new file mode 100644
index 0000000000..c121c1021a
--- /dev/null
+++ b/Zend/tests/php_errormsg_misoptimization.phpt
@@ -0,0 +1,20 @@
+--TEST--
+The variable $php_errormsg shouldn't be optimized as it may be unpredictably modified
+--INI--
+track_errors=1
+--FILE--
+<?php
+
+function test() {
+    $php_errormsg = 1;
+    echo $undef;
+    var_dump($php_errormsg + 1);
+}
+test();
+
+?>
+--EXPECTF--
+Notice: Undefined variable: undef in %s on line %d
+
+Warning: A non-numeric value encountered in %s on line %d
+int(1)
diff --git a/ext/opcache/Optimizer/zend_inference.c b/ext/opcache/Optimizer/zend_inference.c
index 0b2d7f47dd..b853a2e55c 100644
--- a/ext/opcache/Optimizer/zend_inference.c
+++ b/ext/opcache/Optimizer/zend_inference.c
@@ -4152,6 +4152,19 @@ static int zend_infer_types(const zend_op_array *op_array, const zend_script *sc
 	/* Narrowing integer initialization to doubles */
 	zend_type_narrowing(op_array, script, ssa);
 
+	for (j = 0; j < op_array->last_var; j++) {
+		if (zend_string_equals_literal(op_array->vars[j], "php_errormsg")) {
+			/* Mark all SSA vars for $php_errormsg as references,
+			 * to make sure we don't optimize it. */
+			int i;
+			for (i = 0; i < ssa_vars_count; i++) {
+				if (ssa->vars[i].var == j) {
+					ssa_var_info[i].type |= MAY_BE_REF | MAY_BE_ANY | MAY_BE_ARRAY_KEY_ANY | MAY_BE_ARRAY_OF_ANY | MAY_BE_ARRAY_OF_REF;
+				}
+			}
+		}
+	}
+
 	if (ZEND_FUNC_INFO(op_array)) {
 		zend_func_return_info(op_array, script, 1, 0, &ZEND_FUNC_INFO(op_array)->return_info);
 	}