[llvm-dev] [RFC] Strategies for Bootstrapping Compiler-RT builtins

[Anton Korobeynikov via llvm-dev]

> Today building this toolchain with CMake is impossible because you cannot configure the cross-compiled builtins. The failure is a result of CMake’s try_compile function always testing a full compile then link operation. When bootstrapping a cross-compiler this will always fail because linking even the simplest applications fails when you don’t have libclang_rt prebuilt.
The situation is much worse, because it requires not only compiler-rt,
but also all the runtime libraries (libc, libc++, libc++abi) to be
available.

> This is the most complicated approach, but I also think it is the best approach.
This won't work due to dependencies on libc / libc++ / libc++abi.

I think either (1) should be implemented. Or (4) - make the libraries
just to be "shimmed" on fly - proving empty libs for the configure
time just to pacify cmake.

-- 
With best regards, Anton Korobeynikov
Faculty of Mathematics and Mechanics, Saint Petersburg State University