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...for emitting the full symtab. I checked the overhead with a huge internal C++ source. The overhead of symtab + str table compared with byte code with debug is about 3%. More importantly, there is plan to use the symtab also for thinLTO indexing purpose, which makes the space usage completely 'unwasted'. That gets into the details which will follow when the patches are in (with design docs). thanks, David -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20150515/9837a62c/attachment.html>

...r emitting the full symtab. I checked the overhead with a huge internal C++ source. The overhead of symtab + str table compared with byte code with debug is about 3%. More importantly, it is also possible to use the symtab also for index/summary purpose, which makes the space usage completely 'unwasted'. That gets into the details which will follow when patches are in. David On Fri, May 15, 2015 at 5:11 AM, Dave Bozier <seifsta at gmail.com> wrote: > > Are you sure about the additional I/O? With native symtab, existing > tools just need to read those, while plugin based appr...

...%. It's still sizable and could be noticeable if thinLTO can deliver compile times that closer to what resembles builds without LTO as your results suggest. > More importantly, it is also possible to use the symtab also for index/summary purpose, which makes the space usage completely 'unwasted'. That gets into the details which will follow when patches are in. There is symbol information in both the native object symbol table and the bitcode file? isn't that waste? I understand the reasons for using the native object wrapper (compatibility with other tools) and happy with that....

On Thu, May 14, 2015 at 2:09 PM, Eric Christopher <echristo at gmail.com> wrote: > > > On Thu, May 14, 2015 at 1:35 PM Teresa Johnson <tejohnson at google.com> > wrote: > >> On Thu, May 14, 2015 at 1:18 PM, Eric Christopher <echristo at gmail.com> >> wrote: >> > >> > >> > On Thu, May 14, 2015 at 1:11 PM David Blaikie