* RE: ld warning (was Optimization, remove unused code from Image)
@ 2005-01-11 13:59 Eljay Love-Jensen
0 siblings, 0 replies; 3+ messages in thread
From: Eljay Love-Jensen @ 2005-01-11 13:59 UTC (permalink / raw)
To: Madani, Srikanth, VF-DE, gcc-help
Hi Srikanth,
> ld --gc-sections *.o
Don't do that.
Try this instead:
gcc -Wl,--gc-sections *.o
Also note: --gc-sections doesn't work in some environments. (Hmmm, I was
under the vague impression that the gc facility was disabled entirely. But
don't quote me on that.)
HTH,
--Eljay
^ permalink raw reply [flat|nested] 3+ messages in thread
* RE: ld warning (was Optimization, remove unused code from Image)
@ 2005-01-11 15:14 Madani, Srikanth, VF-DE
0 siblings, 0 replies; 3+ messages in thread
From: Madani, Srikanth, VF-DE @ 2005-01-11 15:14 UTC (permalink / raw)
To: Eljay Love-Jensen, gcc-help
Eljay Love-Jensen wrote:
> Try this instead:
>gcc -Wl,--gc-sections *.o
>Also note: --gc-sections doesn't work in some environments. (Hmmm, I
was
>under the vague impression that the gc facility was disabled entirely.
But
>don't quote me on that.)
Thanks, the warning was suppressed. (I also had to link crt* objects)
But my a.out (which runs fine) still has a definition for func3() - the
function which is not referenced by main().
Too bad that the ld man page doesn't specify the hosts on which garbage
collection (--gc-sections) does not work.
Will retry on a Linux machine where everything is GNU, and see if I have
better results there.
Cheers,
Srikanth Madani
^ permalink raw reply [flat|nested] 3+ messages in thread
* RE: ld warning (was Optimization, remove unused code from Image)
@ 2005-01-11 13:48 Madani, Srikanth, VF-DE
0 siblings, 0 replies; 3+ messages in thread
From: Madani, Srikanth, VF-DE @ 2005-01-11 13:48 UTC (permalink / raw)
To: Graham Stott, Sriharsha, gcc-help, Labermeier Norbert
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
^ permalink raw reply [flat|nested] 3+ messages in thread
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