The simplest type of annotation is a flat annotation. The data in
a flat annotation is a pointer to a list of immed values.
See section Immediate Values. By default, annotations read from an input file are flat
annotations. That is, if a SUIF input file contains an annotation with
a name that has not yet been registered, the SUIF library will
automatically register it as a flat annotation.
When creating new flat annotations, you may specify both the annotation
name and a pointer to an immed list. In many cases, however, it
is more convenient to only provide the annotation name and let the
annotation constructor automatically fill the data field with a pointer
to a new list.
For flat annotations, the immeds method merely provides a
shortcut for accessing the data by casting it to an immed_list
pointer. Similarly, the set_immeds method is functionally
equivalent to set_data in this case.