/usr/include/llvm-3.6/llvm/ExecutionEngine/ is in llvm-3.6-dev 1:3.6-2ubuntu1~trusty2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/llvm-3.6/llvm/ExecutionEngine/ExecutionEngine.h
/usr/include/llvm-3.6/llvm/ExecutionEngine/GenericValue.h
/usr/include/llvm-3.6/llvm/ExecutionEngine/Interpreter.h
/usr/include/llvm-3.6/llvm/ExecutionEngine/JITEventListener.h
/usr/include/llvm-3.6/llvm/ExecutionEngine/MCJIT.h
/usr/include/llvm-3.6/llvm/ExecutionEngine/OProfileWrapper.h
/usr/include/llvm-3.6/llvm/ExecutionEngine/ObjectCache.h
/usr/include/llvm-3.6/llvm/ExecutionEngine/RTDyldMemoryManager.h
/usr/include/llvm-3.6/llvm/ExecutionEngine/RuntimeDyld.h
/usr/include/llvm-3.6/llvm/ExecutionEngine/RuntimeDyldChecker.h
/usr/include/llvm-3.6/llvm/ExecutionEngine/SectionMemoryManager.h