Merge New LLVM Pass to Source Tree

For example, we have the following folders:

--- SourceRoot
    --- CMakeLists.txt
    --- MyPass
        --- MyPass.cpp
        --- CMakeLists.txt 

Step 1: change CMakeLists.txt

We need to change the following lines in CMakeLists.txt (inside MyPass folder):

add_library(LLVMmypass MODULE
	MyPass.cpp
)

to

add_llvm_loadable_module(LLVMmypass MODULE
	MyPass.cpp
)

Step 2: put code into source tree

1. Move MyPass folder to llvm/lib/Transforms (LLVM source folder).
2. Add to llvm/lib/Transforms/CMakeLists.txt a line add_subdirectory(MyPass).

Notes:

With this we could use opt -load lib/LLVMmypass.so to run the pass, not necessarily with absolute path for *.so.