[PATCH] D10524: Clang/driver: emulated TLS mode.

[Reid Kleckner]

rnk added a comment.

I don't think it's necessary to warn on the local_exec, etc models. Those flags still provide information about how visible the TLS is, we just don't use it.

It sounds like we should have a -f flag, like -femulated-tls, that controls what we do. The default for Android and MinGW would be to enable it, and that could change over time.

Chandler thinks that this emulation should be done in Clang IRGen, but Nick and I disagree that this should happen late in LLVM. I suggested it could be an IR codegen preparation pass, but David Majnemer disagreed because then it's harder to CSE the call to compute the address of the TLS. Then again, the IR lowering you already have doesn't support CSE, and I think that's fine.


http://reviews.llvm.org/D10524