Graham Stott wrote:
>It is possible to eliminated unused functions on many but not all
targets
>supported by GCC.
>Use -ffunction-sections when compling and and --gc-sections when
linking.
I apologise then. I tried to simulate this on SunOS 5.8.
Wonder if someone can help me with an ld warning I encountered which
seems to be the reason for my corrupted executable.
Three C source files:
$> cat hello.c
int main(void) {
printf("\nHello world!\n");
func1();
exit(0);
}
$>
$> cat fun1.c
void func1(void) {
printf("\nIn function func1()\n");
}
void func2(void) {
func3();
}
$>
$> cat fun2.c
void func3(void) {
printf("\nIn function func3()\n");
}
$>
Compiled with gcc <gcc version 3.3>
$>
$>gcc -ffunction-sections -pedantic-errors -c *.c
$>
Linked with ld <GNU ld version 2.11.2 (with BFD 2.11.2)>
$> ld --gc-sections *.o
/bin/ld: warning: cannot find entry symbol _start; not setting start
address
$>
And my a.out is corrupted:
$> file a.out
can't read ELF header
a.out:
$>
And dumps core:
$> ./a.out
Segmentation fault (core dumped)
$>
Why/how do I have to speficiy the start address?
I did see
http://www.gnu.org/software/binutils/manual/ld-2.9.1/html_node/ld_24.htm
l#SEC24 - am none the wiser.
Help!
Cheers,
Srikanth Madani
