在 2020/1/20 下午6:07, Iain Sandoe 写道:
Hi JunMa,
JunMa <ju...@linux.alibaba.com> wrote:
Hi
Accroding to N4835: When a coroutine is invoked, a copy is created
for each coroutine parameter. While in current implementation, we
only collect used parameters. This may lost behavior inside constructor
and destructor of unused parameters.
This patch change the implementation to collect all parameter.
thanks for the patch.
I am not convinced this is the right way to fix this, we do not want
to increase
the size of the coroutine frame unnecessarily. I would like to check
the lifetime
requirements; such copies might only need to be made local to the ramp
function.
Iain
For type with trivial destructor, There is no need to copy parameter if
it is
never referenced after a reachable suspend
point(return-to-caller/resume) in the
coroutine. Since we are in front end, that should be inital_suspend
point. so we
can create field for type with non-trivial destructor first, and skip
unused parameters
in register_param_uses. I'll update the patch
Regards
JunMa
Bootstrap and test on X86_64, is it OK?
Regards
JunMa
gcc/cp
2020-01-20 Jun Ma <ju...@linux.alibaba.com>
* coroutines.cc (build_actor_fn): Skip rewrite when there is no
param references.
(register_param_uses): Only collect param references here.
(morph_fn_to_coro): Create coroutine frame field for each
function params.
gcc/testsuite
2020-01-20 Jun Ma <ju...@linux.alibaba.com>
* g++.dg/coroutines/torture/func-params-07.C: New test.
<0001-Fix-issue-when-copy-function-parameters-into-corouti.patch>
