public void init(DebugInfoEntry rootDIE) throws IOException {
		diea = DIEAggregate.createSingle(rootDIE);
		line = getProgram().getLine(diea, DW_AT_stmt_list);
	}
Initializes this compunit with the root DIE (first DIE) of the compunit.  This comp unit
isn't usable until this has happened.

@param rootDIE {@link DebugInfoEntry}
@throws IOException if error reading data from the DIE
Ghidra/Features/Base/src/main/java/ghidra/app/util/bin/format/dwarf/DWARFCompilationUnit.java