svn commit: r355969 - head/sys/sys

[Ryan Libby]

Author: rlibby
Date: Sat Dec 21 02:43:20 2019
New Revision: 355969
URL: https://svnweb.freebsd.org/changeset/base/355969

Log:
  gcc: quiet Wattribute for no_sanitize("address")
  
  This is an unfortunate instance where the __has_attribute check does
  not function usefully.  Gcc does have the attribute, but for gcc it only
  applies to functions, not variables, and trying to apply it to a
  variable generates Wattribute.  So far we only apply the attribute to
  variables.  Only enable the attribute for clang, for now.
  
  Reviewed by:	Anton Rang <rang at acm.org>
  Sponsored by:	Dell EMC Isilon
  Differential Revision:	https://reviews.freebsd.org/D22875

Modified:
  head/sys/sys/cdefs.h

Modified: head/sys/sys/cdefs.h
==============================================================================
--- head/sys/sys/cdefs.h	Sat Dec 21 02:40:40 2019	(r355968)
+++ head/sys/sys/cdefs.h	Sat Dec 21 02:43:20 2019	(r355969)
@@ -873,8 +873,12 @@
 /* Function should not be analyzed. */
 #define	__no_lock_analysis	__lock_annotate(no_thread_safety_analysis)
 
-/* Function or variable should not be sanitized, ie. by AddressSanitizer */
-#if __has_attribute(no_sanitize)
+/*
+ * Function or variable should not be sanitized, i.e. by AddressSanitizer.
+ * GCC has the nosanitize attribute, but as a function attribute only, and
+ * warns on use as a variable attribute.
+ */
+#if __has_attribute(no_sanitize) && defined(__clang__)
 #define __nosanitizeaddress	__attribute__((no_sanitize("address")))
 #else
 #define __nosanitizeaddress