49,599 research outputs found
Novel Techniques For Model-Code Synchronization
The orientation of the current software development practice requires efficient model-based iterative solutions. The high costs of maintenance and evolution during the life cycle of the software can be reduced by using tool-aided iterative development. This paper presents how model-based iterative software development can be supported through efficient model-code change propagation. The presented approach facilitates bi-directional synchronization between the modified source code and the refined initial models. The backgrounds of the synchronization technique are three-way abstract syntax tree (AST) differencing and merging. The AST-based solution enables syntactically correct merge operations. OMG's Model-Driven Architecture describes a proposal for platform-specific model creation and source code generation. We extend this vision with the synchronization feature to assist the iterative development. Furthermore, a case study is also provided
Precise Descriptions of VLC Synchronization with CSP Semantic Models
Variable length codes (VLC) have found widespread applications due to their inherent coding efficiency. However, encoder-decoder synchronization becomes critically important for VLC to operate properly. Traditional treebased techniques lack the scalability to analyse the synchronization behaviours of VLC, and simulation techniques are typically used instead for large code sets. Building on an initial paper in which we first described an application of CSP to this domain, we present further advances in this paper. The contributions of this paper are twofold. First, we describe a novel application of the CSP stable failure model to completely describe the VLC synchronization mechanisms. Consequently, we concisely characterize bit patterns that can bring about rapid synchronization. The overall goal is to advance our understanding in this important area of research through an established formal description technique originally developed and used within the computing research community
Tiramisu: A Polyhedral Compiler for Expressing Fast and Portable Code
This paper introduces Tiramisu, a polyhedral framework designed to generate
high performance code for multiple platforms including multicores, GPUs, and
distributed machines. Tiramisu introduces a scheduling language with novel
extensions to explicitly manage the complexities that arise when targeting
these systems. The framework is designed for the areas of image processing,
stencils, linear algebra and deep learning. Tiramisu has two main features: it
relies on a flexible representation based on the polyhedral model and it has a
rich scheduling language allowing fine-grained control of optimizations.
Tiramisu uses a four-level intermediate representation that allows full
separation between the algorithms, loop transformations, data layouts, and
communication. This separation simplifies targeting multiple hardware
architectures with the same algorithm. We evaluate Tiramisu by writing a set of
image processing, deep learning, and linear algebra benchmarks and compare them
with state-of-the-art compilers and hand-tuned libraries. We show that Tiramisu
matches or outperforms existing compilers and libraries on different hardware
architectures, including multicore CPUs, GPUs, and distributed machines.Comment: arXiv admin note: substantial text overlap with arXiv:1803.0041
Dead code elimination based pointer analysis for multithreaded programs
This paper presents a new approach for optimizing multitheaded programs with
pointer constructs. The approach has applications in the area of certified code
(proof-carrying code) where a justification or a proof for the correctness of
each optimization is required. The optimization meant here is that of dead code
elimination.
Towards optimizing multithreaded programs the paper presents a new
operational semantics for parallel constructs like join-fork constructs,
parallel loops, and conditionally spawned threads. The paper also presents a
novel type system for flow-sensitive pointer analysis of multithreaded
programs. This type system is extended to obtain a new type system for
live-variables analysis of multithreaded programs. The live-variables type
system is extended to build the third novel type system, proposed in this
paper, which carries the optimization of dead code elimination. The
justification mentioned above takes the form of type derivation in our
approach.Comment: 19 page
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