A new book providing a detailed and current presentation of the program analysses and transformations that extract the flow of data in computer memory systems. The emphasis is on a framework for the optimization of code for imperative programs and greater computer systems efficiency. Professionals and researchers in software engineering, computer engineering, program design analysis, and compiler design will benefit from its presentation of data-flow methods and memory optimization of compilers.
Overview The motivation of this text lies in what we believe is the inadequacy of current frameworks to reason about the ?ow of data in imperative programs. This inadequacy clearly shows up when dealing with the individual side effects of loop iterations. - deed, we face a paradoxical situation where, on the one hand, a typical program spends most of its execution time iterating or recursing on a few lines of codes, and, on the other hand, current optimization frameworks are clumsy when trying to capture the effects of each incarnation of these few lines¿frameworks we inherited from designs made decades ago. The reasons are manyfold, but one of them stands out: The same concepts have been used, on the one hand, to represent and manipulate programs internally in compilers and, on the other hand, to allow us humans to reason about optimizations. Unfortunately, these two uses have different aims and constraints. An example of such a situation is given by control-?ow graphs of basic blocks, which have been - tremely useful in practice as an internal representation of programs, but which are not always adequate or convenient to formally think about programs and specify their transformations. In some cases, de?nitions based on control-?ow graphs can be overly restrictive. Dominance, studied in Chapter 4, is a good example.
The book focuses on analyses that extract the flow of data, which imperative
programming hides through its use and reuse of memory in computer systems
and compilers. It details some program transformations that conserve this
data flow and introduces a family of analyses, called reaching definition
analyses, to do this task. In addition, it shows that correctness of program
transformations is guaranteed by the conservation of data flow. Professionals
and researchers in software engineering, computer engineering, program
design analysis, and compiler design will benefit from its presentation
of data-flow methods and memory optimization of compilers.
