From 558c6f56e27ffd5a332108243f0be14808082952 Mon Sep 17 00:00:00 2001
From: John Scott <jscott@posteo.net>
Date: Fri, 16 Oct 2020 21:20:33 -0400
Subject: [PATCH] tcc_mallocz: clear with memset only if nonzero size

Even if non-NULL, dereferencing the pointer from malloc(0)
or passing it to memset() may invoke undefined behavior.
---
 libtcc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libtcc.c b/libtcc.c
index ffd0f376..36986328 100644
--- a/libtcc.c
+++ b/libtcc.c
@@ -245,7 +245,8 @@ PUB_FUNC void *tcc_mallocz(unsigned long size)
 {
     void *ptr;
     ptr = tcc_malloc(size);
-    memset(ptr, 0, size);
+    if (size)
+        memset(ptr, 0, size);
     return ptr;
 }