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From: Peter Maydell <peter.maydell@linaro.org>
Date: Tue, 4 Jul 2017 23:34:48 +0100
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Subject: Re: [Qemu-devel] [PATCH v11 04/29] target: [tcg] Add generic
 translation framework
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To: Richard Henderson <rth@twiddle.net>
Cc: 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?B?QWxleCBCZW5uw6ll?= <alex.bennee@linaro.org>

On 4 July 2017 at 23:31, Richard Henderson <rth@twiddle.net> wrote:
> On 07/04/2017 09:14 AM, Peter Maydell wrote:
>> 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.

If you put it in dc->cpu then everywhere that gets the dc gets
the cpu, unavoidably (which is why I'm suggesting it would
be nicer not to do that). If you don't put it in dc then you
can structure your translate code so that pretty much all of
it gets the dc but not the cpu. target/arm/translate-a64.c
does this, for instance.

thanks
-- PMM