On Wed, Aug 19, 2015 at 5:51 AM, Segher Boessenkool <seg...@kernel.crashing.org> wrote: > On Wed, Aug 19, 2015 at 05:23:41AM -0700, H.J. Lu wrote: >> >>> >> > You might have a reason why you want the entry stack address >> >>> >> > instead of the >> >>> >> > frame address, but you didn't really explain I think? Or I missed >> >>> >> > it. >> >> >> >> What would a C program do with this, that it cannot do with the frame >> >> address, that would be useful and cannot be much better done in straight >> >> assembler? Do you actually want to expose the argument pointer, maybe? >> > >> > Yes, we want to use the argument pointer as shown in testcases >> > included in my patch. >> >> Where do we stand on this? We need the hard stack address at >> function entry for x86 without using frame pointer. I added >> __builtin_stack_top since __builtin_frame_address can't give >> us what we want. Should __builtin_stack_top be added to >> middle-end or x86 backend? > > Sorry for not following up; I thought my suggestion was obvious. > > Can you do a __builtin_argument_pointer instead? That should work > for all targets, afaics?
To me, stack top is easier to understand and argument pointer isn't very clear. Does argument pointer exist when there is no argument? But I can live with it. I will update my patch. Thanks. -- H.J.
