Re: What do frame pointers do?

[Bradley Chapman]

Mr. Dunlap,

--- "Randy.Dunlap" <rddunlap@xxxxxxxx> wrote:
> On Sun, 2 Nov 2003 09:00:29 -0800 (PST) Bradley Chapman <kakadu_croc@xxxxxxxxx>
> wrote:
> 
> | What exactly is the purpose of a frame pointer? As far back as I can remember,
> 2.4
> | and 2.6 kernels have supported something called a frame pointer, which slows
> down
> | the kernel slightly but supposedly outputs 'very useful debugging information.'
> | Unfortunately, it doesn't really explain what they are, and for the past few
> months,
> | I haven't seen any hacker gods asking for CONFIG_FRAME_POINTER=y, except for
> Russell
> | King, who wants them compiled for ARM processors for some reason (I grepped the
> | kernel source looking for answers and found a comment which implied this).
> | 
> | Does anyone know where I can find a good explanation of what they are and what
> they
> | do?
> 
> Frame pointers enable more deterministic back tracing of the stack,
> which can be helpful for tracking down bugs.  I build with
> CONFIG_FRAME_POINTER enabled all of the time.
> 
> Note, however, that current 2.6.x Makefile does not allow frame pointers
> to be used with gcc 2.96 since it has some known problems with code generation
> when using frame pointers.
> 
> There is a little discussion of frame pointers in the Intel
> IA-32 Intel® Architecture Software Developer;s Manual Volume 1:
> Basic Architecture
> and
> IA-32 Intel® Architecture Software Developer's Manual Volume 2:
> Instruction Set Reference,
> which are downloadable as .pdf files from developer.intel.com.

OK, thanks for explaining it to me.

> 
> --
> ~Randy

Brad


=====
Brad Chapman

Permanent e-mail: kakadu_croc@xxxxxxxxx

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