[Bug go/60406] recover.go: test13reflect2 test failure

[vogt at linux dot vnet.ibm.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60406

--- Comment #29 from Dominik Vogt <vogt at linux dot vnet.ibm.com> ---
Thanks!

> It's necessary to handle all cases correctly.  But there is nothing wrong
> with using an efficient mechanism when it works, as long as we can correctly
> fall back to a more expensive mechanism when it fails.  I believe that my
> patch does that.

I'm fine with that.  But couldn't this also happen when copying multiple
arguments to the stack?  E.g. if you have an array A and call the function with
something like

  defer(foo(A[0], A[1], ... A[N])

gcc could turn that into a loop for a sufficiently large N?  This may be also
an unlikely case, but a test for this wouldn't hurt either.

> If you like, we can incorporate your patch too, as long as it is only an
> addition to the existing code.  Before calling runtime_callers, we can call
> _Unwind_FindEnclosingFunction.  Then we need only go on to the
> runtime_callers code if _Unwind_FindEnclosingFunction returns NULL, or in the
> cases where d->__makefunc_can_recover is true.

Given that my patch fails to work with indirect function pointers (Power) that
does not seem to be very helpful.