Re: Ping 5! [PATCH, revised]: Track uninitialized variables

[Mark Mitchell <mark@codesourcery.com>]

Caroline Tice wrote:

>>>> I think that giving a link to the original mail in the archives will
>>>> increase the chances of getting a reviewer. And as a rule of thumb,
>>>> anything that makes easier the life of a reviewer will increase the
>>>> chances of getting a patch reviewed.

I've looked at this patch a few times.  To be honest, the reasons I've
never tried to review it is that (a) it's big, and (b) I'm not sure
*why* we want it, (c), the archives and (c) I was secretly hoping Ian
would review it since he'd had some comments before.

Would you please address (b)?  What does having this information in the
debugger allow you to do?  Is it that it helps you debug because you can
tell "uninitialized" from "random weird value"?

Also, what's the memory impact of this patch, given that it makes
VAR_LOCATION bigger?

Why is this target specific?  Do non-GNU debuggers do something bad if
they see DW_OP_GNU_uninit?  If so, do we have to worry about older
versions of GDB?

Does the new dataflow machinery give us any way to get the information
more easily?  Like, can we just ask it about a REG from
one_reg_loc_descriptor, rather than having to pass information around
through multiple functions?

-- 
Mark Mitchell
CodeSourcery
mark@codesourcery.com
(650) 331-3385 x713