Re: [PATCH] Make gdb.arch/i386-biarch-core.exp more robust

[Luis Machado <lgustavo@codesourcery.com>]

On 02/06/2017 11:28 AM, Pedro Alves wrote:
> On 01/31/2017 01:55 PM, Luis Machado wrote:
>> This test attempts to load a x86 core file no matter what the target
>> architecture is. If the architecture is not x86, GDB will not recognize
>> the core file and therefore won't have any memory to inspect. All we will
>> have is a memory read error, resulting in a FAIL.
>>
>> The following patch addresses this by checking if we successfully loaded
>> the core file. If not, just return. Otherwise it keeps testing.
>>
>> gdb/testsuite/ChangeLog:
>>
>> 2017-01-31  Luis Machado  <lgustavo@codesourcery.com>
>>
>> 	* gdb.arch/i386-biarch-core.exp: Return if core file was not
>> 	recognized.
>
> This seems to contradict a bit the point of the test, which says:
>
>> # Test if at least the core file segments memory has been loaded.
>
> when:
>
>> # Wrongly built GDB complains by:
>> # "..." is not a core dump: File format not recognized

You're right. The same message would've come out in a broken gdb trying 
to load the test core file.

>
> I.e., would we be potentially losing coverage?  Assurance
> that we're not I think should be part of the rationale for
> this change.
>
> Does the test pass for you if your non --target=x86 build
> ends up including x86 support, with e.g., --enable-targets=all?
>

It should, because then gdb will recognize it.

> If it does, then maybe we should check whether the GDB
> build supports x86, by e.g., doing:
>
>   gdb_test_multiple "complete set architecture i386" ...
>

Yes, indeed. This test should never try to force a gdb that doesn't 
understand i386/x86-64 core files to load one.

> and seeing if something comes out.
>
> then only do "unsupported" if x86 is not supported, otherwise,
> the memory read failure is really a fail.

Right. In this case it was a fail because gdb didn't even load the core 
file. As opposed to failing to read from a core file memory segment.

I'll adjust this.