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From: Richard Henderson <rth@twiddle.net>
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Date: Fri, 7 Jul 2017 05:18:30 -1000
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Subject: Re: [Qemu-devel] [PATCH v11 10/29] target/i386: [tcg] Refactor
 translate_insn
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To: "Emilio G. Cota" <cota@braap.org>, Eduardo Habkost <ehabkost@redhat.com>, Peter Crosthwaite <crosthwaite.peter@gmail.com>, qemu-devel@nongnu.org, Paolo Bonzini <pbonzini@redhat.com>, =?UTF-8?Q?Alex_Benn=c3=a9e?= <alex.bennee@linaro.org>

On 07/06/2017 11:25 PM, Lluís Vilanova wrote:
>>> /* convert one instruction. s->base.is_jmp is set if the translation must
>>> be stopped. Return the next pc value */
>>> -static target_ulong disas_insn(CPUX86State *env, DisasContext *s,
>>> -                               target_ulong pc_start)
>>> +static target_ulong disas_insn(DisasContextBase *dcbase, CPUState *cpu)
>>> {
>>> +    DisasContext *s = container_of(dcbase, DisasContext, base);
>>> +    CPUX86State *env = cpu->env_ptr;
> 
>> Minor nit: you can pass dc (*s) here directly, no need for container_of
> [...]
> 
> I prefer not to so that the code will work in the future (i.e., not assuming the
> location of base inside disascontext).

There's clearly a misunderstanding here.

Emilio is saying that disas_insn is not a hook and private to the front-end. 
Therefore the argument to the function should be "DisasContet *s" and not 
"DisasContextBase *dcbase".

And I agree.  Passing DisasContext should be preferred where possible.


r~