[LLVMdev] [cfe-dev] RFC: A proposal to move toward using C++11 features in LLVM & Clang / bounding support for old host compilers
"C. Bergström"
cbergstrom at pathscale.com
Mon Oct 28 16:47:35 PDT 2013
For those driving c++11 in clang/llvm - Would it generally be acceptable
to have a "sunrise" period where the preliminary evaluation has been
done (buildbots, compiler evaluate.. etc) and the 1st actual c++11
commit hits the repo. (30-60 days?)
-------------
My concern/thoughts - When we swap out STDCXX for libc++ - We aren't
able to self host clang. This could be entirely *our* fault, but it
hasn't been investigated extensively. (We also see Perennial C++
testsuite regressions which appear to come from libc++, but also not
investiaged/confirmed) Having a sunrise period would allow us to
investigate this as well as report any potentially blocking problems.
Having a gnu-free self hosting[1] policy attached to this would also be
great - that makes a potentially easier backup solution to anyone on
[linux] with older gnu compilers
[1] My simple explanation of self hosting
Stage 1 - g++ builds clang - bootstrapped clang builds it's own runtime
libs -> clang-stage1
Stage 2 - clang-stage1 builds -> clang-stage2
Stage 3 - clang-stage2 builds -> clang-stage3
Typically in such a large c++ codebase like clang - any bad code
generation issues would make stage3 fail. (Not guaranteed, but it's a
pretty good sanity check and way to "dogfood" your own compiler)
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