[llvm-dev] Using C++14 code in LLVM

[David Chisnall via llvm-dev]

On 4 Oct 2016, at 16:36, Zachary Turner via llvm-dev <llvm-dev at lists.llvm.org> wrote:
> 
> I'm talking about for the purposes of giving them access to a toolchain that can build llvm. Not one they can use in their product immediately. They can use the release to build llvm with any set of options they want 

That doesn’t really help.  Moving to a new c++ standard typically means moving to a new C++ standard library.  For me, two years ago, this involved having to build gcc and libstd++ from scratch to get a working toolchain.  Once this is done, I needed to futz with LD_LIBRARY_PATH to make sure that the code run by my students found the correct libstdc++ (note: a new libc++ would hit the same problems, though occasionally a new libstdc++ depends on a new glibc, which causes vastly more pain).

It also means that any students wanting to work on their own machines, rather than on the lab ones, typically have to reproduce the setup, which is decidedly nontrivial.

The bump in cmake requirements was only slightly painful.  A bump in lib[std]c++ requirements is a lot worse.  Please don’t do it unless there is a *really* compelling reason to do so.

David