CS447 Lecture Notes - Lecture 1: Integration Testing, Local Variable, Source Code
Document Summary
Last time, we saw how to construct graphs which summarized a control- ow graph"s structure. Let"s enrich our cfgs with de nitions and uses to enable the use of our data ow criteria. } : implicit de nition for x at the start of a method; The book lists a number of cases of uses, but it boils down to x occurs in an expression that the program evaluates. examples: rhs of an assignment, or as part of a method parameter, or in a conditional. One answer is to be conservative and note that we"ve said that a de nition d reaches a use u if it is possible that the address de ned at d refers to the same address used at u. Our de nition says that both de nitions reach the use. In a compiler, we use intermediate representations to simplify expressions, x.
