How to generate "llvm/datatypes.h"?

I build LLVM myself, but there is still no “llvm/support/datatypes.h”, so I cannot include it in other source files. There are DataTypes.h.cmake and in the same folder which seems to be the template, how to generate the specific datatypes.h?

You can see include/llvm/Support/DataTypes.h in your $(BUILD) directory.
You should specify -I $(BUILD)/include and $(SRC)/include to your
project, as long as you use built-binaries.

Then you should do "make install". Don't to forget to specify
"configure --prefix" or CMAKE_INSTALL_PREFIX.