Re: [PATCH] New C++ abstraction patch

[Michael Snyder <msnyder at cygnus dot com>]

Daniel Berlin wrote:
> 
> Michael Elizabeth Chastain <chastain@cygnus.com> writes:
> 
> > Hi Daniel,
> >
> > > I plan on using [^0-9]D[1-3]Ev$
> >
> > I am suspicious of the [^0-9] part.  I just made a class named "B1",
> > and its destructor name is "_ZN2B1D2Ev".  Indeed, I can't figure out
> > what problem the [^0-9] is trying to solve anyways.
> 
> Make sure it's not the beginning of a name accidently.
> Of course, it's pointless, but I added it before I added the "ends in
> Ev" rule.
> 
> I think the right thing is to do "^_Z.*[1-9][a-zA-Z_][a-zA-Z0-9_]+D[0-2]Ev$", since the class
> name always comes right before the destructor.
> This also makes sure we don't accidently get the classname, even if
> it's D[0-2].
> 
> I generated this regex from staring at the demangler for a while.
> :)
> 
> It's really (to break it down in case you see a part i've gotten wrong)
> _Z.*<mangled classname regex><mangled destructor name regex>Ev$
> 
> 1-9 because you can't have a class name of length 0.
> 
> I think i have a few valid identifier characters missing, i'll double
> check it if you think this regex would work if i added them.
> 
> Otherwise, i'll look at cleaning up the ternary search tree stuff for
> demangled names and submitting it.
> 
> Temporarily, of course, i'm more than happy to just take the speed hit
> in the name of correctness, and getting v3 abi supported properly.

When you speak of a speed hit, are you speaking of symbol-file-load time,
or expression evaluation time?  I think expression evaluation is far 
less important to optimize for speed than symbol loading.  Lots of people
complain about the time gdb takes to start up on a new symbol file, while
very few (that I'm aware of) complain about the performance during 
expression evaluation.