[PATCH] Add a "probe-stack" attribute

[John Kåre Alsaker]

I have a patch to add __probestack to compiler-rt. No other such
function have a configurable name, so I don't see why __probestack
should be different.

I'm not sure how to test for #3 as I don't think any calling
convention has RAX as live-in.

I don't know if #4 even handles the edge case(s), which is why I added
an assertion, so I don't know how to test for those. I can add a test
for the non-edge case though.

The stack-probe-size attribute interacts as expected (it just controls
the stack allocation size for which probes are required).

On Fri, Jan 16, 2015 at 10:30 PM, Reid Kleckner <rnk at google.com> wrote:
> On Fri, Jan 16, 2015 at 12:43 PM, David Majnemer <david.majnemer at gmail.com>
> wrote:
>>
>> Reid, I'm not so sure.
>>
>> We already have a probe-stack-size attribute, how does this attribute
>> interact with that one?  Which targets have a __probestack that can be
>> called?
>
>
> There aren't any targets that use __probestack. It's new this patch. Maybe
> the attribute should take the symbol name as a value so it's user
> controlled?