and using the latter in DIBuilder::createArtificialType and
DIBuilder::createObjectPointerType methods as well as introducing
mirroring DISubprogram::cloneWithFlags and
DIBuilder::createArtificialSubprogram methods.
The primary goal here is to add createArtificialSubprogram to support
a pass downstream while keeping the method consistent with the
existing ones and making sure we don't encourage changing already
created DI-nodes.
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D47615
llvm-svn: 333806