Introduce DIBuilder. It is intended to be a front-end friendly interface to...

Introduce DIBuilder. It is intended to be a front-end friendly interface to emit debuggging information entries in LLVM IR.

To create debugging information for a pointer, using DIBUilder front-end just needs
	DBuilder.CreatePointerType(Ty, Size);
instead of
	DebugFactory.CreateDerivedType(llvm::dwarf::DW_TAG_pointer_type,
                                       TheCU, "", getOrCreateMainFile(),
                                       0, Size, 0, 0, 0, OCTy);

llvm-svn: 118248