Thread safety: added basic handling for pt_guarded_by/var and guarded_by/var annotations. We identify situations where we are accessing (reading or writing) guarded variables, and report an error if the appropriate locks are not held.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@138774 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed