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Re: Designs for better debug info in GCC
On Dec 18, 2007, Robert Dewar <dewar@adacore.com> wrote:
> Alexandre Oliva wrote:
>> Yep. Sometimes code just is optimized away. Can't stop that without
>> harming optimizations.
> OK, so you are agreeing that good debuggability is impossible
> with all the optimizations in place, so once again, let's have
> an optimziation level that optimizes as far as possible without
> harming debuggability.
I don't oppose such an optimization level, even though I don't know
that we agree on what "good debuggability" stands for.
It's just that changing optimizations is precisely *against* the goals
of my current project. So, don't expect significant efforts to this
end from me at this time.
>> If dwarf line number programs were smarter, we could perhaps encode
>> multiple lines for the same instruction, along with conditions to tell
>> when the instruction applies to such or such lines, and even more
>> fancy stuff like that. But line number programs don't let us express
>> this in Dwarf3.
> So, that's not an option.
Yup. Best we can do right now is to emit the condition line number.
--
Alexandre Oliva http://www.lsd.ic.unicamp.br/~oliva/
FSF Latin America Board Member http://www.fsfla.org/
Red Hat Compiler Engineer aoliva@{redhat.com, gcc.gnu.org}
Free Software Evangelist oliva@{lsd.ic.unicamp.br, gnu.org}