Program transformation

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

A case for source-level transformations in MATLAB

Abstract: In this paper, we discuss various performance overheads in MATLAB codes and propose different program transformation strategies to overcome them. In particular, we demonstrate that high-level source-to-source transformations of MATLAB programs are effective in obtaining substantial performance gains regardless of whether programs are interpreted or later compiled into C or FORTRAN. We argue that automating such transformations provides a promising area of future research.

Tracing Lazy Functional Computations Using Redex Trails

Abstract: We describe the design and implementation of a system for tracing computations in a lazy functional language The basis of our tracing method is a program transformation carried out by the compiler: transformed programs compute the same values as the original, but embedded in functional data structures that also include redex trails showing how the values were obtained A special-purpose display program enables detailed but selective exploration of the redex trails, with cross-links to the source program

Refactoring for reentrancy

Abstract: A program is reentrant if distinct executions of that program on distinct inputs cannot affect each other. Reentrant programs have the desirable property that they can be deployed on parallel machines without additional concurrency control. Many existing Java programs are not reentrant because they rely on mutable global state. We present a mostly-automated refactoring that makes such programs reentrant by replacing global state with thread-local state and performing each execution in a fresh thread. The approach has the key advantage of yielding a program that is obviously safe for parallel execution; the program can then be optimized selectively for better performance. We implemented this refactoring in Reentrancer, a practical Eclipse-based tool. Reentrancer successfully eliminated observed reentrancy problems in five single-threaded Java benchmarks. For three of the benchmarks, Reentrancer enabled speedups on a multicore machine without any further code modification.

Using program transformations to derive line-drawing algorithms

Abstract: : A wide variety of line-drawing algorithms can be derived by applying program transformations to a simple, obviously correct algorithm. The transformations increase the algorithm's performance and eliminate the need for floating-point computations. Two familiar algorithms are derived in this way: Bresenham's algorithm and the digital differential analyzer (DDA). The transformations are then used to derive several highly parallel variants of Bresenham's algorithm, designed for use on displays that can generate more than one pixel at a time. The treatment shows a complete, extended example of the practical use of program transformations. Moreover, the transformations derive Bresenham's algorithm without recourse to complex geometric arguments.

Fix Me Up: Repairing Access-Control Bugs in Web Applications

Abstract: Access-control policies in Web applications ensure that only authorized users can perform security-sensitive operations. These policies usually check user credentials before executing actions such as writing to the database or navigating to privileged pages. Typically, every Web application uses its own, hand-crafted program logic to enforce access control. Within a single application, this logic can vary between different user roles, e.g., administrator or regular user. Unfortunately, developers forget to include proper access-control checks, a lot. This paper presents the design and implementation of FIXMEUP, a static analysis and transformation tool that finds access-control errors of omission and produces candidate repairs. FIXMEUP starts with a high-level specification that indicates the conditional statement of a correct access-control check and automatically computes an interprocedural access-control template (ACT), which includes all program statements involved in this instance of accesscontrol logic. The ACT serves as both a low-level policy specification and a program transformation template. FIXMEUP uses the ACT to find faulty access-control logic that misses some or all of these statements, inserts only the missing statements, and ensures that unintended dependences did not change the meaning of the access-control policy. FIXMEUP then presents the transformed program to the developer, who decides whether to accept the proposed repair. Our evaluation on ten real-world PHP applications shows that FIXMEUP is capable of finding subtle accesscontrol bugs and performing semantically correct repairs.