From: Paul Eggert <eggert@cs.ucla.edu>
Date: Mon, 22 Apr 2019 03:36:56 +0000 (-0700)
Subject: Port dump_bitset_clear to -fsanitize=undefined
X-Git-Tag: emacs-27.0.90~3154
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=4a5ed6b05a71593cda33af4da44f30eb84b51f30;p=emacs.git

Port dump_bitset_clear to -fsanitize=undefined

* src/pdumper.c (dump_bitset_clear):
Pacify -fsanitize=undefined by avoiding memset (NULL, x, 0),
which strictly speaking has undefined behavior although it
works on all production platforms I know.
---

diff --git a/src/pdumper.c b/src/pdumper.c
index 3facd523e4a..6ab82769ec9 100644
--- a/src/pdumper.c
+++ b/src/pdumper.c
@@ -4923,7 +4923,8 @@ static void
 dump_bitset_clear (struct dump_bitset *bitset)
 {
   int xword_size = sizeof (bitset->bits[0]);
-  memset (bitset->bits, 0, bitset->number_words * xword_size);
+  if (bitset->number_words)
+    memset (bitset->bits, 0, bitset->number_words * xword_size);
 }
 
 struct pdumper_loaded_dump_private