> On 10 Dec 2024, at 01:02, Jason Merrill <ja...@redhat.com> wrote: > > On 12/9/24 2:39 PM, Iain Sandoe wrote: >>> On 9 Dec 2024, at 19:34, Jason Merrill <ja...@redhat.com> wrote: >>> >>> On 12/9/24 2:00 PM, Iain Sandoe wrote: >>>>> On 9 Dec 2024, at 18:56, Jason Merrill <ja...@redhat.com> wrote: >>>>> >>>>> On 11/29/24 8:47 AM, Iain Sandoe wrote: >>>>>> Tested on x86_64-darwin, x86_64-linux, >>>>>> OK for trunk? >>>>>> thanks >>>>>> Iain >>>>>> --- 8< --- >>>>>> At present, we only update the suspend index when we actually are >>>>>> at the stage that the coroutine is considered suspended. This is >>>>>> on the basis that it is UB to resume or destroy a coroutines that >>>>>> is not suspended (and therefore we never need to access this value >>>>>> otherwise). However, it is possible that someone could set a debug >>>>>> breakpoint on the resume which can be reached without suspending >>>>>> if await_ready() returns true. >>>>> >>>>> Hmm, https://eel.is/c++draft/expr#await-5 reads to me like there's only a >>>>> suspend point if await_ready() returns false? >>>> yes, exactly. >>>> which would mean that we only updated the suspend index in that case >>>> (which is fine if the only observer of the index is the coroutines code). >>>> This change is entirely to cater for the fact that a debugger can observe >>>> the coroutine in states other than those that can be reached from >>>> resume() or destroy(). >>> >>> I guess I'm getting confused by the comment referring to a suspend point, >>> where actually we're dealing with the resume index, which is independent of >>> the suspend point? >> Yes - although the coroutines code only ever inspects it after a suspension >> - a debugger could inspect it at any time and, logically, it should icrement >> as we pass each “if (awaiter.await_ready())” independent of whether that >> results in a suspension. > > So can we change the comment and variable name to refer to resume index > instead of suspend? OK with that adjustment.
Yes, that makes more sense, pushed as attached. thanks Iain
0001-c-coroutines-Make-the-resume-index-consistent-for-de.patch
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