On Wed, Aug 19, 2015 at 10:08:01AM -0700, H.J. Lu wrote:
> > Maybe something like (heavily cut'n'pasted):
> >
> >
> > @deftypefn {Built-in Function} {void *} __builtin_argument_address (void)
> > This function is similar to @code{__builtin_frame_address} with an
> > argument of 0, but it returns the address of the incoming arguments to
> > the current function rather than the address of its frame.
>
> This doesn't make senses when there is no argument or arguments
> are passed in registers.
Sure, but see the weasel-words below ("The exact...")
> To me, argument pointer is a virtual concept
> and an implementation detail internal to GCC. I am not sure if another
> compiler can implement it based on this description.
The same is true for frame_address, on many machines.
> > The exact definition of this address depends upon the processor and the
> > calling convention. Usually some arguments are passed in registers and
> > the rest on the stack, and this builtin returns the address of the first
> > argument that is on the stack.
Segher
