[Lldb-commits] [PATCH] D40283: lldb: Use the DWARF linkage name when importing C++ methods

Nelson Elhage via lldb-commits lldb-commits at lists.llvm.org
Thu Jan 11 09:53:35 PST 2018

I can try to take some time to benchmark, hopefully this weekend or so.

I do want to reiterate that this without this change debugging binaries
linked against libstdc++ is badly degraded, since recent libstdc++  uses
ABI tags on ~any methods that touch a std::string.

- Nelson

On Thu, Jan 11, 2018 at 7:18 AM Davide Italiano <dccitaliano at gmail.com>

> On Thu, Jan 11, 2018 at 2:01 AM, Pavel Labath via lldb-commits
> <lldb-commits at lists.llvm.org> wrote:
> > On 10 January 2018 at 22:51, Greg Clayton <clayborg at gmail.com> wrote:
> >> The right solution seems to be adding some sort of custom GNU ABI tag
> to the DWARF. I know that won't help with existing binaries, but it sounds
> too expensive to set the ASM name for everything.
> >>
> >
> > What makes you think it will be expensive? I don't know much about
> > clang internals, but I think something has to provide a mangled name
> > in any case. So, if we don't specify a mangled name, clang will have
> > to do the mangling itself. For all I know, setting the asm attribute
> > may actually speed things up, as clang could avoid doing some extra
> > work.
> >
> > I think it would be interesting to try to measure the
> > performance/memory footprint impact of just setting the asm attribute
> > everywhere.
> >
> Indeed. If somebody has the time to put into this I think it's
> something worth benchmarking before declaring victory (or defeat).
> Thanks,
> --
> Davide
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