Re: [PATCH] disas: Remove libvixl disassembler

[Claudio Fontana]

On 6/9/22 10:57, Daniel P. Berrangé wrote:
> On Thu, Jun 09, 2022 at 10:47:24AM +0200, Thomas Huth wrote:
>> On 08/06/2022 17.51, Paolo Bonzini wrote:
>>> On 6/3/22 19:35, Thomas Huth wrote:
>>>> On 03/06/2022 19.26, Claudio Fontana wrote:
>>>>> On 6/3/22 18:42, Thomas Huth wrote:
>>>>>> The disassembly via capstone should be superiour to our old vixl
>>>>>> sources nowadays, so let's finally cut this old disassembler out
>>>>>> of the QEMU source tree.
>>>>>>
>>>>>> Signed-off-by: Thomas Huth <thuth@redhat.com>
>>>>>
>>>>> agreed, one thought: at the time I added this thing, I had to
>>>>> add C++ compilation support,
>>>>> maybe something we can now drop if there are no more C++ users?
>>>>
>>>> I thought about that, too, but we still have disas/nanomips.cpp left
>>>> and the Windows-related files in qga/vss-win32/* .
>>>
>>> That is pure C++ so it does not need the extra complication of "detect
>>> whether the C and C++ compiler are ABI-compatible" (typically due to
>>> different libasan/libtsan implementation between gcc and clang).  So
>>> it's really just nanoMIPS that's left.
>>
>> Ok, so the next theoretical question is: If we get rid of the nanomips.cpp
>> file or convert it to plain C, would we then simplify the code in configure
>> again (and forbid C++ for the main QEMU code), or would we rather keep the
>> current settings in case we want to re-introduce more C++ code again in the
>> future?
> 
> It doesn't feel very compelling to have just 1 source file that's
> C++ in QEMU. I'm curious how we ended up with this nanomips.cpp
> file - perhaps it originated from another project that was C++
> based ?
> 
> The code itself doesn't look like it especially needs to be using
> C++. There's just 1 class there and every method is associated
> with that class, and external entry point from the rest of QEMU
> is just one boring method. Feels like it could easily have been
> done in C.
> 
> Personally I'd prefer it to be converted to C, and if we want to
> add any C++ in future it should be justified & debated on its
> merits, rather than as an artifact of any historical artifacts
> such as the code in configure happening to still exist.
> 
> With regards,
> Daniel

I'll take a look at it, maybe I can turn it to C fairly quickly.

Ciao,

Claudio