Software engineers are faced with a dilemma. They want to write general and wellstructured programs that are flexible and easy to maintain. On the other hand, generality has a price: efficiency. A specialized program solving a particular problem is often significantly faster than a general program. However, the development of specialized software is time-consuming, and is likely to exceed the production of today’s programmers. New techniques are required to solve this so-called software crisis. Partial evaluation is a program specialization technique that reconciles the benefits of generality with efficiency. This thesis presents an automatic partial evaluator for the Ansi C programming language. The content of this thesis is analysis and transformation of C programs. We develop several analyses that support the transformation of a program into its generating extension. A generating extension is a program that produces specialized programs when executed on parts of the input. The thesis contains the following main results.

Partial evaluation provides a unifying paradigm for a broad spectrum of work in

ing with credit is permitted. To copy otherwise, to republish, to post on servers, or to redistribute to lists, requires prior specific permission and/or a fee. Request permissions from Publications Dept, ACM Inc., fax + 1 (212) 869-0481, or <permissions@acm.org>. 1 Specializing Shaders Brian Guenter, Todd B. Knoblock, Erik Ruf * Microsoft Research Abstract We have developed a system for interactive manipulation of shading parameters for three dimensional rendering. The system takes as input user-defined shaders, written in a subset of C, which are then specialized for interactive use. Since users typically experiment with different values of a single shader parameter while leaving the others constant, we can benefit by automatically generating a specialized shader that performs only those computations depending on the parameter being varied; all other values needed by the shader can be precomputed and cached. The specialized shaders are as much as 95 times faster than the origi...

Designing and implementing generic software components is encouraged by languages such as object-oriented ones and commonly advocated in most application areas. Generic software components have many advantages among which the most important is reusability. However, it comes at a price: genericity often incurs a loss of efficiency. This paper presents an approach aimed at reconciling genericity and efficiency. To do so, we introduce declarations to the Java language to enable a programmer to specify how generic programs should be specialized for a particular usage pattern. Our approach has been implemented as a compiler from our extended language into standard Java. 1 Introduction The object-oriented paradigm has well-recognized advantages for application design, and more specifically for program structure. It makes it possible to decompose an application in terms of well-defined, generic components, closely corresponding to the structure of the modeled problem. This structuring leads...

Automatic program specialization can derive e#cient implementations from generic components, thus reconciling the often opposing goals of genericity and e#ciency. This technique has proved useful within the domains of imperative, functional, and logical languages, but so far has not been explored within the domain of object-oriented languages.

Since a binding-time analysis determines how an off-line partial evaluator will specialize a program, the accuracy of the binding-time information directly determines the degree of specialization. We have designed and implemented a binding-time analysis for an imperative language, and integrated it into our partial evaluator for C, called Tempo [11]. This binding-time analysis includes a number of new features, not available in any existing partial evaluator for an imperative language, which are critical when specializing existing programs such as operating system components [27,28]. ffl Flow sensitivity. A different binding-time description is computed for each program point, allowing the same variable to be considered static at one program point and dynamic at another. ffl Context sensitivity. Each function call is analyzed with the context of the call site, generating multiple binding-time annotated instances of the same function definition. ffl Return sensitivity. A different bi...

The object-oriented style of programming facilitates program adaptation and enhances program genericness, but at the expense of efficiency. We demonstrate experimentally that state-of-the-art Java compilation technology fails to compensate for the use of object-oriented abstractions to implement generic programs, and that program specialization can be used to eliminate these overheads. We present an automatic program specializer for Java, and demonstrate experimentally that significant speedups in program execution time can be obtained through automatic specialization. Although automatic program specialization could be seen as overlapping with existing optimizing compiler technology, we show that specialization and compiler optimization are in fact complementary. 1 Introduction Object-oriented languages encourage a style of programming that facilitates program adaptation. Encapsulation enhances code resilience to program modifications and increases the possibilities for di...

Introduction: What is partial evaluation? Partial evaluation is a technique to partially execute a program, when only some of its input data are available. Consider a program p requiring two inputs, x 1 and x 2 . When specific values d 1 and d 2 are given for the two inputs, we can run the program, producing a result. When only one input value d 1 is given, we cannot run p, but can partially evaluate it, producing a version p d1 of p specialized for the case where x 1 = d 1 . Partial evaluation is an instance of program specialization, and the specialized version p d1 of p is called a residual program. For an example, consider the following C function p

Design patterns offer many advantages for software development, but can introduce inefficiency into the final program. Program specialization can eliminate such overheads, but is most effective when targeted by the user to specific bottlenecks. Consequently, we propose that these concepts are complementary. Program specialization can optimize programs written using design patterns, and design patterns provide information about the program structure that can guide specialization. Concretely, we propose specialization patterns, which describe how to apply program specialization to optimize uses of design patterns.

In order to exploit specialization opportunities that exist in programs written by researchers outside of the programming language community, a partial evaluator needs to effectively treat existing realistic applications. Our empirical studies have demonstrated real-sized applications extensively use non-liftable values such as pointers and data structures. Therefore, it is essential that the binding-time analysis accurately treats nonliftable values. To achieve this accuracy, we introduce the notion of use sensitivity, and present a use-sensitive binding-time analysis for C programs which is obtained by a forward analysis followed by a backward analysis. This analysis has been implemented and integrated into our partial evaluator for C, called Tempo. To validate the effectiveness of our analysis and demonstrate that use sensitivity is critical to obtain highly-specialized programs, we have conducted experimental studies on various components of existing operating systems code. Our res...