[src/trunk]: src/sys/sys Add macro to mark a symbol as weak. Use it to mark t...

[joerg <joerg%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/8c0bef856822
branches:  trunk
changeset: 334828:8c0bef856822
user:      joerg <joerg%NetBSD.org@localhost>
date:      Mon Dec 08 20:50:11 2014 +0000

description:
Add macro to mark a symbol as weak. Use it to mark the end of a linker
set as empty linker set otherwise violate the aliasing rules of C by
presenting zero sized objects.

diffstat:

 sys/sys/cdefs_elf.h |  10 ++++++++--
 1 files changed, 8 insertions(+), 2 deletions(-)

diffs (31 lines):

diff -r 01088d876361 -r 8c0bef856822 sys/sys/cdefs_elf.h
--- a/sys/sys/cdefs_elf.h       Mon Dec 08 20:44:59 2014 +0000
+++ b/sys/sys/cdefs_elf.h       Mon Dec 08 20:50:11 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: cdefs_elf.h,v 1.46 2014/08/26 09:03:17 christos Exp $  */
+/*     $NetBSD: cdefs_elf.h,v 1.47 2014/12/08 20:50:11 joerg Exp $     */
 
 /*
  * Copyright (c) 1995, 1996 Carnegie-Mellon University.
@@ -65,6 +65,12 @@
     __asm(".weak " _C_LABEL_STRING(#sym));
 
 #if __GNUC_PREREQ__(4, 0)
+#define        __weak  __attribute__((__weak__))
+#else
+#define        __weak
+#endif
+
+#if __GNUC_PREREQ__(4, 0)
 #define        __weak_reference(sym)   __attribute__((__weakref__(#sym)))
 #else
 #define        __weak_reference(sym)   ; __asm(".weak " _C_LABEL_STRING(#sym))
@@ -169,7 +175,7 @@
 
 #define        __link_set_decl(set, ptype)                                     \
        extern ptype * const __link_set_start(set)[] __dso_hidden;      \
-       extern ptype * const __link_set_end(set)[] __dso_hidden
+       extern ptype * const __link_set_end(set)[] __weak __dso_hidden
 
 #define        __link_set_count(set)                                           \
        (__link_set_end(set) - __link_set_start(set))