Summary:
Teach clang to mark thread wrappers for thread_local variables with
hidden visibility when the original variable is marked with hidden
visibility. This is necessary on Darwin which exposes the thread wrapper
instead of the thread variable. The thread wrapper would previously
always be created with default visibility unless it had
linkonce*/weak_odr linkage.
Reviewers: rjmccall
Reviewed By: rjmccall
Differential Revision: https://reviews.llvm.org/D56818
llvm-svn: 351457
Vlad Tsyrklevich