Program transformation

About: Program transformation is a research topic. Over the lifetime, 2468 publications have been published within this topic receiving 73415 citations.

The Cetus Source-to-Source Compiler Infrastructure: Overview and Evaluation

Abstract: This paper provides an overview and an evaluation of the Cetus source-to-source compiler infrastructure. The original goal of the Cetus project was to create an easy-to-use compiler for research in automatic parallelization of C programs. In meantime, Cetus has been used for many additional program transformation tasks. It serves as a compiler infrastructure for many projects in the US and internationally. Recently, Cetus has been supported by the National Science Foundation to build a community resource. The compiler has gone through several iterations of benchmark studies and implementations of those techniques that could improve the parallel performance of these programs. These efforts have resulted in a system that favorably compares with state-of-the-art parallelizers, such as Intel's ICC. A key limitation of advanced optimizing compilers is their lack of runtime information, such as the program input data. We will discuss and evaluate several techniques that support dynamic optimization decisions. Finally, as there is an extensive body of proposed compiler analyses and transformations for parallelization, the question of the importance of the techniques arises. This paper evaluates the impact of the individual Cetus techniques on overall program performance.

Methods and apparatus for optimizing programs in the presence of exceptions

Abstract: A method and several variants are provided for analyzing and transforming a computer program such that instructions may be reordered even across instructions that may throw an exception, while strictly preserving the precise exception semantics of the original program. The method uses program analysis to identify the subset of program state that needs to be preserved if an exception is thrown. Furthermore, the method performs a program transformation that allows dependence constraints among potentially excepting instructions to be completely ignored while applying program optimizations. This transformation does not require any special hardware support, and requires a compensation code to be executed only if an exception is thrown, i.e., no additional instructions need to be executed if an exception is not thrown. Variants of the method show how one or several of the features of the method may be performed.

Search-based failure discovery using testability transformations to generate pseudo-oracles

Abstract: Testability transformations are source-to-source program transformations that are designed to improve the testability of a program. This paper introduces a novel approach in which transformations are used to improve testability of a program by generating a pseudo-oracle. A pseudo-oracle is an alternative version of a program under test whose output can be compared with the original. Differences in output between the two programs may indicate a fault in the original program. Two transformations are presented. The first can highlight numerical inaccuracies in programs and cumulative roundoff errors, whilst the second may detect the presence of race conditions in multi-threaded code. Once a pseudo-oracle is generated, techniques are applied from the field of search-based testing to automatically find differences in output between the two versions of the program. The results of an experimental study presented in the paper show that both random testing and genetic algorithms are capable of utilizing the pseudo-oracles to automatically find program failures. Using genetic algorithms it is possible to explicitly maximize the discrepancies between the original programs and their pseudo-oracles. This allows for the production of test cases where the observable failure is highly pronounced, enabling the tester to establish the seriousness of the underlying fault.

On the correctness of unfold/fold transformation of normal and extended logic programs

Abstract: We show that the framework for unfold/fold transformation of logic programs, first proposed by Tamaki and Sato and later extended by various researchers, preserves various nonmonotonic semantics of normal logic programs, especially preferred extension, partial stable models, regular model, and stable theory semantics. The primary aim of this research is to adopt a uniform approach for every semantics of normal programs, and that is elegantly achieved through the notion of semantic kernel. Later, we show that this framework can also be applied to extended logic programs, preserving the answer set semantics.