From: Nikita Popov <nikita.ppv@gmail.com>
Date: Fri, 28 Aug 2020 15:24:21 +0000 (+0200)
Subject: Avoid ubsan warning with dummy cache slot addr
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=86364013f996b4b99ae9d218350a3effdfd6587a;p=php

Avoid ubsan warning with dummy cache slot addr
---

diff --git a/Zend/zend_compile.c b/Zend/zend_compile.c
index b54b435ae9..18c149de54 100644
--- a/Zend/zend_compile.c
+++ b/Zend/zend_compile.c
@@ -62,7 +62,10 @@ typedef struct _zend_loop_var {
 
 static inline uint32_t zend_alloc_cache_slots(unsigned count) {
 	if (count == 0) {
-		return (uint32_t) -1;
+		/* Even if no cache slots are desired, the VM handler may still want to acquire
+		 * CACHE_ADDR() unconditionally. Returning zero makes sure that the address
+		 * calculation is still legal and ubsan does not complain. */
+		return 0;
 	}
 
 	zend_op_array *op_array = CG(active_op_array);