This is the mail archive of the
gcc-help@gcc.gnu.org
mailing list for the GCC project.
Re: var-track-assignment.
- From: Ian Lance Taylor <iant at google dot com>
- To: vijay nag <vijunag at gmail dot com>
- Cc: "gcc-help at gcc dot gnu dot org" <gcc-help at gcc dot gnu dot org>
- Date: Mon, 25 Nov 2013 09:50:13 -0800
- Subject: Re: var-track-assignment.
- Authentication-results: sourceware.org; auth=none
- References: <CAKhyrx_XwnuOD6zdH+A3g9NrvP+8rwn2Em0YApM82+w8e6Leog at mail dot gmail dot com>
On Sun, Nov 24, 2013 at 9:31 PM, vijay nag <vijunag@gmail.com> wrote:
>
> Compilation of production build(-O2 optimization turned on) of my
> project is taking a very long time and on further analysis I found
> that most of the compile time is eaten up by "var-tracking assignment"
> gcc pass. I see significant improvements in build time If I use
> "-fno-var-tracking" and also I don't intend to debug production build.
> However it is important that we be able to do post-mortem analysis of
> core file on production build. I tried loading a sample core-file in
> gdb and could see gdb complaining "optimized out" for couple of stack
> variables. So the question is, does "-fno-var-tracking" have any
> impact on post-mortem analysis of core file or does it just disable
> run time debugging capabilities ?
Using -fno-var-tracking will mean that in some cases when using a core
file you will not be able to use gdb to see the values of local
variables. It won't affect using gdb with the core file to see
backtraces or global variables. You can of course disassemble the
code and examine the registers to find the local variable values in
the core file, to the extent that they exist at all. You'll have to
decide what is more important to you.
Ian