__hidden_ver1() macro handles USER_LABEL_PREFIX incorrectly ?
Mike Frysinger
vapier@gentoo.org
Sun Jan 15 22:21:00 GMT 2006
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
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