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Subject: Re: variables optimized out
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References: <CAA99N-OKyxzVaJ4ayXRUGAoovNtHFXTpOXPkwhdw9k3LEMnOtw@mail.gmail.com>
From: "Kristian A. Hiorth" <kah@kahnews.net>
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Date: Sun, 3 Jan 2016 15:30:56 +0100
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On 01/03/2016 02:38 PM, robbinson defau wrote:
> Hi all,
>
> Im debugging some issues in the kernel and as the kernel is compiled by
> default with -O2, a lot of variables are optimized out. So i made changes
> to make.conf (CFLAGS and COPTFLAGS).\
>
> All builds fine, but I get the weirdest of panics that most certainly not
> happen with -O2. So it's likely i'm doing something wrong. What would be
> the correct way to be able to debug the kernel and have it build such that
> locals and function arguments are not optimized out?
>
> Thanks in advance,
>
> /DF

Hi,

sounds like stack overflows, did you try increasing kernel stack size? 
Stuff like WITNESS causes a lot of stack growth when the optimizer 
inlines fewer calls.

I've run an -O0 kernel with
options 	KSTACK_PAGES=6

without too many problems.

Hope this helps,
Kristian