Abstract: Techniques and tools relating to state-based source code annotation are described. For example, described techniques include flexible techniques for describing object states with annotations. In one aspect, properties of data structures in source code are described using state-defining code annotations. For example, specification structs can be used to describe an arbitrary set of states of objects, thereby improving the capabilities of the annotation language in terms of richness of program description. Specification structs also help to avoid annotating large numbers of individual fields in data structures by allowing several individual fields to be described by a single specification struct. Other aspects of a source code annotation language also are described.

Abstract: Techniques and tools for implementing a source code annotation language are described. In one aspect, keywords are added to a function interface to define a contract for the function independent of function call context. In another aspect, annotations are inserted at global variables, formal parameters, return values, or user-defined types. The annotations include, for example, properties and qualifiers. A property can indicate, for example, a characteristic of a buffer. In another aspect, an annotation indicates that a value has usability properties sufficient to allow a function to rely on the value, where the usability properties depend on value type.