http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54933
Joey Ye <joey.ye at arm dot com> changed:
What |Removed |Added
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CC| |joey.ye at arm dot com
--- Comment #1 from Joey Ye <joey.ye at arm dot com> 2013-01-18 06:33:20 UTC ---
This issue especially impacts "retarget", where library functions are
"retargeted" to user implementations. Retarget is a common practice in
bare-metal development but runs into "defined in discarded section" with LTO
enabled.
Here is the retarget case:
# gcc version 4.8.0 20130115 (experimental) [trunk revision 195189] (GCC)
# GNU ld (GNU Binutils) 2.23.51.20130111
$ cat main.c
int main()
{
return puts("Hello");
}
// it works if following line is enabled
// __attribute__ ((used))
int _write(int c)
{
/* Do something */
return c;
}
$ cat lib-a.c
int puts(const char * str)
{
return _write(*str);
}
$ gcc -flto -c -o lib-a.o lib-a.c
$ ar rv liba.a lib-a.o
r - lib-a.o
$ gcc main.c liba.a -flto --entry=main -nostdlib -o l
`_write' referenced in section `.text' of liba.a(lib-a.o): defined in discarded
section `.text' of /tmp/ccwUUKiA.o (symbol from plugin)
collect2: error: ld returned 1 exit status
