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Re: [PATCH v2 5/9] x86: improve handling of insns with ambiguous operand sizes
On 11.11.2019 19:27, H.J. Lu wrote:
> On Mon, Nov 11, 2019 at 1:29 AM Jan Beulich <jbeulich@suse.com> wrote:
>>
>> On 08.11.2019 16:54, H.J. Lu wrote:
>>> On Fri, Nov 8, 2019 at 12:09 AM Jan Beulich <jbeulich@suse.com> wrote:
>>>> On 07.11.2019 18:47, H.J. Lu wrote:
>>>>> I don't think DefaultSize matters for them either in AT&T syntax.
>>>>> and I don't think we should add DefaultSize to more instructions.
>>>>
>>>> Then _again_ - what is your alternative suggestion?
>>>
>>> Don't add DefaultSize to more instructions.
>>
>> So I think I've recalled meanwhile: The issue is with us not wanting
>> to issue diagnostics on e.g. LGDT despite it allowing multiple
>> operand sizes. Instead, just like for PUSH/POP etc we want to silently
>> default to the most appropriate operand size for the mode. Hence
>> adding DefaultSize seems very applicable to me here.
>>
>
> This is a problem only for Intel syntax and DefaultSize affects both
> Intel syntax and AT&T syntax.
Are you talking about before or after this patch? Recall that the
changes here bring AT&T syntax handling more in line with Intel
one, just that for AT&T talk is about absent suffixes while for
Intel talk is about absent operand size modifiers.
> Since we can't have both DefaultSize
> and IgnoreSize at the same time, can they be merged and leave it
> for Intel syntax to deal with it?
I don't think they can be merged. See the draft patch you've sent
the other day actually splitting DefaultSize into two bits.
Jan