On 2015.08.12 at 13:03 -0600, Jeff Law wrote: > On 08/12/2015 12:57 PM, Richard Sandiford wrote: > > Jeff Law <l...@redhat.com> writes: > >> On 08/10/2015 06:05 AM, tbsaunde+...@tbsaunde.org wrote: > >>> From: Trevor Saunders <tbsaunde+...@tbsaunde.org> > >>> > >>> Hi, > >>> > >>> In many places gcc puts classes in the anon namespace so the compiler can > >>> tell > >>> they do not get inheritted from to enable better devirtualization. > >>> However > >>> debugging code in the anon namespace can be a pain, and the same thing > >>> can be > >>> accomplished more directly by marking the classes as final. When > >>> bootstrapping > >>> stage 3 should always be built in C++14 mode now, and of course will > >>> always be > >>> newer than gcc 4.7, so these classes will always be marked as final there. > >>> AIUI cross compilers are supposed to be built with recent gcc, which I > >>> would > >>> tend to think implies newer than 4.7, so they should also be built with > >>> these > >>> classes marked as final. I believe that means in all important cases > >>> this works just as well as the anon namespace. > >>> > >>> bootstrapped + regtested on x86_64-linux-gnu, ok? > >>> > >>> Trev > >>> > >>> > >>> gcc/ChangeLog: > >>> > >>> 2015-08-10 Trevor Saunders <tbsau...@tbsaunde.org> > >>> > >>> * compare-elim.c, dce.c, dse.c, gimple-ssa-isolate-paths.c, > >>> gimple-ssa-strength-reduction.c, graphite.c, init-regs.c, > >>> ipa-pure-const.c, ipa-visibility.c, ipa.c, mode-switching.c, > >>> omp-low.c, reorg.c, sanopt.c, trans-mem.c, tree-eh.c, > >>> tree-if-conv.c, tree-ssa-copyrename.c, tree-ssa-dce.c, > >>> tree-ssa-dom.c, tree-ssa-dse.c, tree-ssa-forwprop.c, > >>> tree-ssa-sink.c, tree-ssanames.c, tree-stdarg.c, tree-tailcall.c, > >>> tree-vect-generic.c, tree.c, ubsan.c, var-tracking.c, > >>> vtable-verify.c, web.c: Use GCC_FINAL instead of the anonymous > >>> namespace. > >> OK. > > > > I was hoping someone else was going to speak up since I seem > > to have been posting a few negative messages recently, but I think > > this is really a step in the wrong direction. I think the code > > was using anonymous namespaces in exactly the way they were > > intended to be used. > No need to worry about seeming to be negative. > > > The problem is you can't get to stuff in the anonymous namespace easily > in the debugger. There was talk of fixing that, but I don't think it > ever went forward on the gdb side. > > If gdb were to get fixed so that debugging this stuff was easier, then > I'd fully support putting things back into the anonymous namespace.
For the record here the gdb bug in question: https://sourceware.org/bugzilla/show_bug.cgi?id=16874 It even has a patch attached, that improves the issue. -- Markus
