linux-kernel - Re: Re: [PATCH 2/4] x86: Move instruction decoder data into header

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Date:	Tue, 15 Apr 2014 12:10:51 +0900
From:	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
To:	Sasha Levin <sasha.levin@...cle.com>
Cc:	vegard.nossum@...cle.com, penberg@...nel.org,
	jamie.iles@...cle.com, hpa@...or.com, mingo@...hat.com,
	tglx@...utronix.de, x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: Re: [PATCH 2/4] x86: Move instruction decoder data into header

(2014/04/15 11:28), Sasha Levin wrote:
> On 04/14/2014 09:41 PM, Masami Hiramatsu wrote:
>> (2014/04/15 2:44), Sasha Levin wrote:
>>>> Right now we generate data for the instruction decoder and place it
>>>> as a code file which gets #included directly (yuck).
>>>>
>>>> Instead, make it a header which will also be usable by other code
>>>> that wants to use the data in there.
>> Hmm, making the generated data into a header file may clone
>> the data table instances for each object file. Since the inat
>> table is not so small, I think we'd better just export the tables.
> 
> The tables are defined as static, so the compiler drops them
> once it detects they are not used.

No, I meant that if the table is used in the different object files,
will the copies of the tables be compiled in several different
instances?

And I can't see the part which makes the tables static in this patch...

> I feel it would be easier to let the compiler do it's job rather
> than do optimizations we don't need to do and which will complicate
> the code quite a bit.

I haven't tend to optimize it, but just encapsulate it, to hide from other parts.

Thank you,


-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@...achi.com


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