Detecting wrong linkage on mips PIC code

[Atsushi Nemoto <anemo at mba dot ocn dot ne dot jp>]

This simple queer program does not work on mips-linux if compiled with
-O2 option.  It works if compiled with -O.  I'm using gcc 3.4.4 and
binutils 2.16.1.

int main(int argc, char **argv)
{
	static long int random(void);
	random();
	return 0;
}

Declaring random() as a static function is definitely wrong, but I
wonder why none of gcc, as, or ld give me any error or warning.

With -O2, gcc outputs:

	.set	noreorder
	...
	lw	$25,%got(random)($28)
	nop
	addiu	$25,$25,%lo(random)
	jalr	$25
	nop

This does not work.

With -O, gcc outputs:

	.set	reorder
	...
	la	$25,random
	jal	$25

This works.

If I correctly declared random() as extern function, gcc -O2 outputs:

	.set	noreorder
	...
	lw	$25,%call16(random)($28)
	nop
	jalr	$25

This works (of course).

In first case, final output is:

  4008c8:	8f998058 	lw	t9,-32680(gp)
  4008cc:	00000000 	nop
  4008d0:	27390000 	addiu	t9,t9,0
  4008d4:	0320f809 	jalr	t9
  4008d8:	00000000 	nop

where value in GOT (-32680(gp)) is 00000000.


Is it possible to detect this sort of error when compiling or linking?

---
Atsushi Nemoto
I'm not on this ML.  Please CC to me.  Thank you.