[Dwarf-Discuss] Does gcc optimization impacts retrieving Dwarf information?

[Richard Guenther]

On Thu, Nov 19, 2009 at 2:55 PM, Mark Wielaard <mjw@redhat.com> wrote:
> On Thu, 2009-11-19 at 19:15 +0530, M. Mohan Kumar wrote:
>> On 11/19/2009 04:30 PM, Mark Wielaard wrote:
>> > On Wed, 2009-11-18 at 18:19 +0530, M. Mohan Kumar wrote:
>> >> Are VTA patches part of mainline gcc now? If not, where could we get the
>> >> VTA patches?
>> >
>> > The VTA implementation is in mainline gcc now. There are also some
>> > backports to gcc 4.4, like the gcc that Fedora 12 ships with.
>>
>> Thank you very much for the info. Is there any option needs to be passed
>> to gcc to enable this VTA feature?

It is enabled by default when -g is specified.

Richard.

> See the following options from:
> http://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html#Debugging-Options
>
> -fvar-tracking
>        Run variable tracking pass. It computes where variables are
>        stored at each position in code. Better debugging information is
>        then generated (if the debugging information format supports
>        this information).
>
>        It is enabled by default when compiling with optimization (-Os,
>        -O, -O2, ...), debugging information (-g) and the debug info
>        format supports it.
>
>
> -fvar-tracking-assignments
>        Annotate assignments to user variables early in the compilation
>        and attempt to carry the annotations over throughout the
>        compilation all the way to the end, in an attempt to improve
>        debug information while optimizing. Use of -gdwarf-4 is
>        recommended along with it.
>
>        It can be enabled even if var-tracking is disabled, in which
>        case annotations will be created and maintained, but discarded
>        at the end.
>
>
>