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From: Richard Henderson <rth@twiddle.net>
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Date: Tue, 4 Jul 2017 12:31:51 -1000
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Subject: Re: [Qemu-devel] [PATCH v11 04/29] target: [tcg] Add generic
 translation framework
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To: Peter Maydell <peter.maydell@linaro.org>, QEMU Developers <qemu-devel@nongnu.org>, Paolo Bonzini <pbonzini@redhat.com>, Peter Crosthwaite <crosthwaite.peter@gmail.com>, "Emilio G. Cota" <cota@braap.org>, =?UTF-8?Q?Alex_Benn=c3=a9e?= <alex.bennee@linaro.org>

On 07/04/2017 09:14 AM, Peter Maydell wrote:
> On 4 July 2017 at 19:59, Lluís Vilanova <vilanova@ac.upc.edu> wrote:
>> Richard Henderson writes:
>>> Any reason not to stuff the cpu pointer into the DisasContextBase instead of
>>> passing it around separately?
>>
>> None, really. I'll move it from DisasContext (in targets where it's present)
>> into DisasContextBase, and use that one everywhere.
> 
> I kind of like not having CPUState* in DisasContext, because
> it enforces the rule that you can't read from fields of
> it inside the target translate.c code without jumping through
> a hoop (ie copying the info from CPUState->foo to
> DisasContext->foo). That then acts as a useful flag in code
> review (or when writing the code) to confirm that foo really
> is constant for the life of the simulation (or to recommend
> using a TB flag instead).

I don't see how the spelling "cpu" vs "dc->cpu" really affects that.

More practically, I don't see that "cpu" will actually be used by most of those 
hooks.  But because of things like cpu->some_target_feature, it's kind of hard 
to predict.


r~