Re: [RFC/PATCH] Testsuite: set sysroot when using gdbserver

[Pedro Alves <palves@redhat.com>]

On 03/28/2019 12:50 PM, Alan Hayward wrote:
> 

>>
>> IMO we could also look at this from the perspective that the slowness is
>> something that we should tackle, improve in gdb somehow.  For example, we
>> could improve caching a lot.  We have a readahead cache for vFile:pread, but
>> we could also have a persistent cache layer, so that we wouldn't be
>> downloading the same shared library files over and over again.
> 
> Will caching only effect extended gdbserver (which AIUI, gdbserver stays alive
> between tests)? It’s not an area I’ve (yet) looked at.

It'd work for plain target remote too.  What I meant by persistent is that it
would persist across gdb invocations, saved in a cache directory, similarly
to where we put the new index cache.  We could e.g., key that on build id.

> 
>>
>>>
>>> I don’t know much about how the board files work, but, looks like I can
>>> just add a flag via “set_board_info” in the relevant board files.
>>>
>>> I can then check for it at the end of gdbserver_start. Or instead check
>>> at the same place “target remote” is run (although I couldn’t find where
>>> that was yesterday!).
>>
>> Probably just adding
>>
>> set GDBFLAGS "${GDBFLAGS} -ex \"set sysroot /\""
>>
>> to testsuite/boards/local-board.exp is all you'd need.
> 
> 
> That fixes it! And logically makes sense too.
> Works fine on the buildbot slave.
> 
>>
>> I think it'd be good to have a testcase in gdb.server/ that explicitly
>> tests debugging a bit with "set sysroot target:" enabled, so that we
>> don't lose coverage of that.
> 
> Agreed. Happy to raise that as a new patch next week - trying to avoid
> writing anything new as I’m not really here today.

That'd be great, thanks.

> 
> Is the following patch ok for pushing?
> 
> Given you told me the line to add, I wasn’t sure if I should be adding you
> to the changelog line too :)
> 

Fine with me either way.

Patch is OK.

Thanks,
Pedro Alves