[cfe-dev] [libc++] much longer build time of my project using libc++ 5.0 vs 3.5.2

Dimitry Andric via cfe-dev cfe-dev at lists.llvm.org
Sat Nov 18 05:15:34 PST 2017

Do you have some sort of test case?  For example, a standalone .cpp file which includes a bunch of libc++ headers, and which now takes much more time to compile?

It would be interesting to see where this regressed, if it did.


> On 17 Nov 2017, at 21:04, chen hsu via cfe-dev <cfe-dev at lists.llvm.org> wrote:
> Hi, my project has been using libc++/c++abi 3.5.2 for two years, and recently I am upgrading it to libc++/c++abi 5.0, only to find that the build time for our project increased dramatically, from 100 minutes to 160 minutes on a 6-core intel-CPU, same situation for both debug and release build. The compiler is clang 5.0. The comparison is pretty fair - same machine and compiler, same codebase, the only difference is the C++ headers. Is there a way to improve? It's kind of blocker for our adoption of libc++/c++abi 5.0, as it takes too long for our developers to build.
> Thanks a lot.
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