From: John Marino <draco@marino.st>
Date: Sun, 5 Feb 2012 16:14:25 +0000 (+0100)
Subject: cdefs: Rework and augment visibility attributes
X-Git-Tag: v3.4.0rc~1283
X-Git-Url: https://gitweb.dragonflybsd.org/dragonfly.git/commitdiff_plain/25fffb38ee50e7671cd4c12b5eca431a391ff8d5

cdefs: Rework and augment visibility attributes

One macro based on GCC visibility functions was already defined,
__exported.  However, it was marked as available for all GCC versions
when it fact it was introduced with gcc 4.0.

There was no macro for hidden visibility attributes, so the macros
__dso_hidden and __dso_public were borrowed from NetBSD.  __dso_public
is an alias for __exported.  The definition for all three macros were
made on the condition that the gcc version used is 4.0 or later.
---

diff --git a/sys/sys/cdefs.h b/sys/sys/cdefs.h
index 5b761008d5..a737c18887 100644
--- a/sys/sys/cdefs.h
+++ b/sys/sys/cdefs.h
@@ -41,12 +41,6 @@
 #ifndef	_SYS_CDEFS_H_
 #define	_SYS_CDEFS_H_
 
-#if defined(__GNUC__)
-#define __exported __attribute__((__visibility__("default")))
-#else
-#define __exported
-#endif
-
 #if defined(__cplusplus)
 #define	__BEGIN_DECLS	extern "C" {
 #define	__END_DECLS	}
@@ -299,6 +293,16 @@
 #define __ARRAY_ZERO
 #endif
 
+#if __GNUC_PREREQ__(4, 0)
+#define __exported	__attribute__((__visibility__("default")))
+#define __dso_public	__attribute__((__visibility__("default")))
+#define __dso_hidden	__attribute__((__visibility__("hidden")))
+#else
+#define __exported
+#define __dso_public
+#define __dso_hidden
+#endif
+
 /*
  * A convenient constructor macro, GCC 4.3.0 added priority support to
  * constructors, provide a compatible interface for both.