[tsan] Add support for GCD IO channels on Darwin

This patch adds interceptors for dispatch_io_*, dispatch_read and dispatch_write functions. This avoids false positives when using GCD IO. Adding several test cases.

Differential Revision: http://reviews.llvm.org/D21889



git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@275071 91177308-0d34-0410-b5e6-96231b3b80d8
7 files changed