[RFC] Make "run" work on macOS 10.13

[Pedro Alves]

On 06/29/2018 09:55 PM, Tom Tromey wrote:
> I would like some feedback on this patch.
> 
> On macOS 10.13.5, "run" does not work in gdb.  There are two cases:
> 
> 1. If I forget to "set startup-with-shell off", then gdb will fail due
>    to the system integrity protection feature.  I believe this happens
>    because gdb is not allowed to debug the shell.
> 
>    You can find many sites advocating "set startup-with-shell off",
>    but it seems to me that it is friendlier for gdb to simply do it by
>    default.

Judging from stackoverflow, input redirection is a common-ish thing
for users to do.  Maybe we could reuse Eli's input redirection
emulation for Windows here:

 https://sourceware.org/ml/gdb-patches/2016-10/msg00832.html

Doesn't have to be you or in this patch of course.  Just a suggestion.

> 
>    One option here might be to do this conditionally based on the
>    version of the OS.
> 
> 2. I found that gdb was setting the solib breakpoint incorrectly,
>    causing a failure.  Adding the load address to the notifier address
>    makes this work for me.  I suspect this would regress earlier
>    versions of macOS, but I have no way to test that; one idea might
>    be to only do this when gdb_dyld_all_image_infos::version == 15.

14 vs 15 behaving differently does sound consistent with:

  https://sourceware.org/ml/gdb-patches/2018-06/msg00167.html

Thanks,
Pedro Alves