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__hidden_ver1() macro handles USER_LABEL_PREFIX incorrectly ?
- From: Mike Frysinger <vapier at gentoo dot org>
- To: libc-alpha at sources dot redhat dot com
- Date: Sun, 15 Jan 2006 17:23:08 -0500
- Subject: __hidden_ver1() macro handles USER_LABEL_PREFIX incorrectly ?
i'm playing with the blackfin target which defines USER_LABEL_PREFIX to "_"
and i seem to be ending up with symbols with too many _ prefixes ... i traced
it back to the libc_hidden_def() macro in libc-symbols.h
for example, this bit of code:
int __libc_close(int fd) { return fd; }
strong_alias(__libc_close,close)
libc_hidden_proto(close)
libc_hidden_def(close)
on a target where USER_LABEL_PREFIX is defined to "", we'd correctly end up
with global symbols __libc_close and close, and an internal hidden __GI_close
however, on an a target where USER_LABEL_PREFIX is defined to "_", we'd end up
with global symbols ___libc_close and _close, an internal hidden ___GI_close,
and an undefined reference to ____GI_close
i'm thinking it's because __hidden_ver1() is incorrectly using
__hidden_asmname() when defining the __EI_##name alias ... the alias name is
processed by gcc itself which will insert USER_LABEL_PREFIX, so calling
__hidden_asmname() which also inserts USER_LABEL_PREFIX for us generates an
alias to a double prefixed asmname
if i change __hidden_ver1() to call __hidden_asmname1() with an empty prefix
for the alias, my final object ends up with the correct prefixes ... sample
file along with patch are attached, tested against x86_64 and bfin elf
targets
current cvs:
$ gcc -c hidden-test.c && readelf -s hidden-test.o | grep close
8: 0000000000000000 12 FUNC GLOBAL DEFAULT 1 __libc_close
9: 0000000000000000 12 FUNC GLOBAL DEFAULT 1 close
10: 0000000000000000 12 FUNC GLOBAL HIDDEN 1 __GI_close
$ bfin-elf-gcc -c hidden-test.c && readelf -s hidden-test.o | grep close
6: 00000000 14 FUNC GLOBAL DEFAULT 1 ___libc_close
7: 00000000 14 FUNC GLOBAL HIDDEN 1 ___GI_close
8: 00000000 0 NOTYPE GLOBAL DEFAULT UND ____GI_close
with my simple patch:
$ gcc -DFIX -c hidden-test.c && readelf -s hidden-test.o | grep close
8: 0000000000000000 12 FUNC GLOBAL DEFAULT 1 __libc_close
9: 0000000000000000 12 FUNC GLOBAL DEFAULT 1 close
10: 0000000000000000 12 FUNC GLOBAL HIDDEN 1 __GI_close
$ bfin-elf-gcc -DFIX -c hidden-test.c && readelf -s hidden-test.o | grep close
6: 00000000 14 FUNC GLOBAL DEFAULT 1 ___libc_close
7: 00000000 14 FUNC GLOBAL DEFAULT 1 _close
8: 00000000 14 FUNC GLOBAL HIDDEN 1 ___GI_close
-mike
# define strong_alias(name, aliasname) _strong_alias(name, aliasname)
# define _strong_alias(name, aliasname) \
extern __typeof (name) aliasname __attribute__ ((alias (#name)));
#define __hidden_proto_hiddenattr(attrs...) \
__attribute__ ((visibility ("hidden"), ##attrs))
#define __hidden_asmname(name) \
__hidden_asmname1 (__USER_LABEL_PREFIX__, name)
#define __hidden_asmname1(prefix, name) __hidden_asmname2(prefix, name)
#define __hidden_asmname2(prefix, name) #prefix name
#ifndef FIX
#define __hidden_ver1(local, internal, name) \
extern __typeof (name) __EI_##name __asm__(__hidden_asmname (#internal)); \
extern __typeof (name) __EI_##name \
__attribute__((alias (__hidden_asmname (#local))))
#else
#define __hidden_ver1(local, internal, name) \
extern __typeof (name) __EI_##name __asm__(__hidden_asmname (#internal)); \
extern __typeof (name) __EI_##name \
__attribute__((alias (__hidden_asmname1 (,#local))))
#endif
#define hidden_proto(name, attrs...) \
__hidden_proto (name, __GI_##name, ##attrs)
#define __hidden_proto(name, internal, attrs...) \
extern __typeof (name) name __asm__ (__hidden_asmname (#internal)) \
__hidden_proto_hiddenattr (attrs);
#define libc_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
#define hidden_def(name) __hidden_ver1(__GI_##name, name, name);
#define libc_hidden_def(name) hidden_def (name)
int __libc_close(int fd) { return fd; }
strong_alias(__libc_close,close)
libc_hidden_proto(close)
libc_hidden_def(close)
2006-01-15 Mike Frysinger <vapier@gentoo.org>
* include/libc-symbols.h (__hidden_ver1): Use __hidden_asmname1() for
__EI_ aliase names.
--- include/libc-symbols.h 6 Nov 2005 02:05:18 -0000 1.73
+++ include/libc-symbols.h 15 Jan 2006 22:14:30 -0000
@@ -570,7 +570,7 @@ for linking")
# define __hidden_ver1(local, internal, name) \
extern __typeof (name) __EI_##name __asm__(__hidden_asmname (#internal)); \
extern __typeof (name) __EI_##name \
- __attribute__((alias (__hidden_asmname (#local))))
+ __attribute__((alias (__hidden_asmname1 (,#local))))
# define hidden_ver(local, name) __hidden_ver1(local, __GI_##name, name);
# define hidden_data_ver(local, name) hidden_ver(local, name)
# define hidden_def(name) __hidden_ver1(__GI_##name, name, name);