On Wed, Aug 15, 2001 at 09:53:20AM +1000, Simon Gee wrote:
> >
> > .set noreorder
> > .set noat
> > move $1,$31 # save current return address
> > jal _mcount
> > subu $sp,$sp,8 # _mcount pops 2 words from stack
> > .set reorder
> > .set at
> >
>
> Given this assembler sequence, which is produced by:
>
> /* Output assembler code to FILE to increment profiler label # LABELNO
> for profiling a function entry. */
>
> #define FUNCTION_PROFILER(FILE, LABELNO) \
> { \
> if (TARGET_MIPS16) \
> sorry ("mips16 function profiling"); \
> fprintf (FILE, "\t.set\tnoreorder\n"); \
> fprintf (FILE, "\t.set\tnoat\n"); \
> fprintf (FILE, "\tmove\t%s,%s\t\t# save current return address\n", \
> reg_names[GP_REG_FIRST + 1], reg_names[GP_REG_FIRST + 31]); \
> fprintf (FILE, "\tjal\t_mcount\n"); \
> fprintf (FILE, \
> "\t%s\t%s,%s,%d\t\t# _mcount pops 2 words from stack\n", \
> TARGET_64BIT ? "dsubu" : "subu", \
> reg_names[STACK_POINTER_REGNUM], \
> reg_names[STACK_POINTER_REGNUM], \
> Pmode == DImode ? 16 : 8); \
> fprintf (FILE, "\t.set\treorder\n"); \
> fprintf (FILE, "\t.set\tat\n"); \
> }
>
> in mips.h, wouldn't the positioning of "subu $sp,$sp,8" imply that it was
> intended to be within "jal"'s delay slot (the expansion of jal is really
> annoying!) ? This being the case, the stack adjustment may have had to have
> been made before the call to _mcount is made.
*sigh* Yes, I think the adjustment was meant to be made before the
call. Perhaps binutils should warn about things in the "delay slot" of a
macro?
Doing the adjustment before the call would fix the problem that I'm
seeing.
--
Daniel Jacobowitz Carnegie Mellon University
MontaVista Software Debian GNU/Linux Developer
