Re: [PATCH v2] Enable gdb.cp/ambiguous.exp with GCC and clang

[Pedro Alves <pedro@palves.net>]

On 8/27/20 5:18 PM, Gary Benson wrote:
> Pedro Alves wrote:
>> On 8/27/20 4:07 PM, Gary Benson wrote:
>>> Pedro Alves wrote:
>>>> On 8/27/20 11:39 AM, Gary Benson wrote:
>>>>> Luis Machado wrote:
>>>>>> I get the following, under Ubuntu 18.04 (GCC 7.x) with this commit...
>>>>>>
>>>>>> FAIL: gdb.cp/ambiguous.exp: print x.x
>>>>>> FAIL: gdb.cp/ambiguous.exp: print n.x
>>>>>> FAIL: gdb.cp/ambiguous.exp: print j.x
>>>>>> FAIL: gdb.cp/ambiguous.exp: print jva1.x
>>>>>> FAIL: gdb.cp/ambiguous.exp: print jva2.x
>>>>>> FAIL: gdb.cp/ambiguous.exp: print (A1)j
>>>>>> FAIL: gdb.cp/ambiguous.exp: print (A1)jva1
>>>>>>
>>>>>> Is the test really supposed to run with older GCC's?
>>>>>
>>>>> Maybe not.  Though, I don't know what version of GCC it ought to
>>>>> start working on, so it's hard to know what to do.  I could leave
>>>>> the "-w" in for GCC < 10, and add an extra check to make it bail
>>>>> out for GCC <= your version, Luis?  With a suitable comment to
>>>>> mention that that's not set in stone?
>>>>
>>>> I'm seeing it fail with GCC 9 and clang 10 as well.
>>>>
>>>> Actually, the testcase can't be working _anywhere_.  It's testing a
>>>> feature that is gone from GDB.
>>> [snip]
>>>> ...search_struct_field does not handle the ambiguous field
>>>> case nowadays.  Somehow it got lost over the years.
>>>> That seems like a regression.  I wrote up a patch that adds
>>>> it back (though different), but it exposed other latent
>>>> bugs...  Sigh.  I'll post it soon.
>>>
>>> So the test would start passing if that patch was added?
>>> Should we leave the test alone, or XFAIL the cases that
>>> fail, or...?
>>
>> I'm adjusting / fixing the testcase at the same time as I'm
>> patching GDB.  So for now, do nothing.
> 
> Awesome, thank you.

I've sent it now, here:

 [PATCH] Reject ambiguous C++ field accesses
 https://sourceware.org/pipermail/gdb-patches/2020-August/171526.html