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Re: [Dwarf-Discuss] Does gcc optimization impacts retrieving Dwarf information?
- From: Richard Guenther <richard dot guenther at gmail dot com>
- To: Mark Wielaard <mjw at redhat dot com>
- Cc: "M. Mohan Kumar" <mohan at in dot ibm dot com>, dwarf-discuss at lists dot dwarfstd dot org, gcc at gcc dot gnu dot org, SHARYATHI NAGESH <sharyathi at in dot ibm dot com>
- Date: Thu, 19 Nov 2009 15:01:24 +0100
- Subject: Re: [Dwarf-Discuss] Does gcc optimization impacts retrieving Dwarf information?
- References: <20090528085225.GA4492@in.ibm.com> <4A1E5FF4.7080608@eagercon.com> <20090528144027.GB19495@elastic.org> <4A1EB3F3.7090203@eagercon.com> <20090529085812.GA31047@in.ibm.com> <1243590102.4800.48.camel@hermans.wildebeest.org> <4B03ED3D.6010708@in.ibm.com> <1258628425.5693.7.camel@springer.wildebeest.org> <4B054BF3.1030802@in.ibm.com> <1258638926.5693.23.camel@springer.wildebeest.org>
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.
>
>
>