Code generation for a systolic computer

An experiment of a mechanical code generation for a programmable systolic computer is reported. Two-dimensional systolic arrays are automatically reduced to one dimension, and code is generated for the one-dimensional processor array Warp. The technique is demonstrated with two examples: matrix multiplication and LU decomposition.     

Code generation for Event-B

International Journal on Software Tools for Technology Transfer - Event-B is a modelling language and a formal methods approach for correct construction of software. This paper presents our work on...     

Code generation with a recursive optimizer

This paper describes a general purpose optimizer used to construct a new code generator for an existing Coral 66 compiler. The optimizer is recursive and gives the one pass code generator some of the advantages of a multiple pass scheme by ‘pipelining’ short sequences of linear intermediate code at each activation level.     

Formal requirements modelling with executable use cases and coloured Petri nets

This paper presents executable use cases (EUCs), which constitute a model-based approach to requirements engineering. EUCs may be used as a supplement to model-driven development (MDD) and can describe and link user-level requirements and more technical software specifications. In MDD, user-level requirements are not always explicitly described, since usually it is sufficient that one provides a specification, or platform-independent model, of the software that is to be developed. Therefore, a combination of EUCs and MDD may have potential to cover the path from user-level requirements via specifications to implementations of computer-based systems.     

面向RISC-DSP处理器的代码生成和优化

随着嵌入式系统应用的发展，高效和小型化是其主要特点，这对目标代码质量的要求也越来越高。针对自行设计的32位具有RISC DSP结构的媒体处理器MD 32特有的体系结构特点，提出C编译器支持的，在汇编代码级通过指令调度和转换指令操作数及其类型的代码优化方法，实现输出高效的并行指令。统计数据表明：代码执行效率平均可以提高15％，而代码密度平均提高12％。     

RSF: a formalism for executable requirement specifications

RSF is a formalism for specifying and prototyping systems with time constraints. Specifications are given via a set of transition rules. The application of a transition rule is dependent upon certain events. The occurrence times of the events and the data associated with them must satisfy given properties. As a consequence of the application of a rule, some events are generated and others are scheduled to occur in the future, after given intervals of time. Specifications can be queried, and the computation of answers to queries provides a generalized form of rapid prototyping. Executability is obtained by mapping the RSF rules into logic programming. The rationale, a definition of the formalism, the execution techniques which support the general notion of rapid prototyping and a few examples of its use are presented     

数据流控制流相叠加的可执行测试序列生成研究

提出了一种可执行的测试序列的自动生成策略。先从UML模型中提取出协议模型的EFSM信息,然后利用变迁可执行性分析自动生成可执行的测试序列。该生成策略同时结合了数据流测试和控制流测试的优点,既具有比较高的错误覆盖率,又对通信协议中的数据部分进行了充分的测试,从而提高了一致性测试的效率。     

An executable formal semantics for UML-RT

We propose a formal semantics for UML-RT, a UML profile for real-time and embedded systems. The formal semantics is given by mapping UML-RT models into a language called kiltera, a real-time extension of the \(\pi \)-calculus. Previous attempts to formalize the semantics of UML-RT have fallen short by considering only a very small subset of the language and providing fundamentally incomplete semantics based on incorrect assumptions, such as a one-to-one correspondence between “capsules” and threads. Our semantics is novel in several ways: (1) it deals with both state machine diagrams and capsule diagrams; (2) it deals with aspects of UML-RT that have not been formalized before, such as thread allocation, service provision points, and service access points; (3) it supports an action language; and (4) the translation has been implemented in the form of a transformation from UML-RT models created with IBM’s RSA-RTE tool, into kiltera code. To our knowledge, this is the most comprehensive formal semantics for UML-RT to date.     

Design notations for secure software: a systematic literature review

In the past 10 years, the research community has produced a significant number of design notations to represent security properties and concepts in a design artifact. These notations are aimed at documenting and analyzing security in a software design model. The fragmentation of the research space, however, has resulted in a complex tangle of different techniques. Hence, practitioners are confronted with the challenging task of scouting the right approach from a multitude of proposals. Similarly, it is hard for researchers to keep track of the synergies among the existing notations, in order to identify the existing opportunities for original contributions. This paper presents a systematic literature review that inventorizes the existing notations and provides an in-depth, comparative analysis for each.     

Data-bound variables for WS-BPEL executable processes

Standard BPEL (Business Process Execution Language) variables, if used to store the data from a data store, cannot be automatically synchronized with the data source in case other applications change the data during the BPEL process execution, which is a common occurrence particularly for long-running BPEL processes. BPEL also does not provide a mechanism for active monitoring of changes of data that would support automated detection and handling of such changes. This paper proposes a new type of BPEL variables, called data-bound variables. Data-bound variables are automatically synchronized with the data source and thus eliminate the need to implement data synchronization manually. To provide support for data-bound variables, we propose specific extensions to BPEL and the use of appropriate Data Access Services (DAS) that act as data providers. We introduce new BPEL activities to load, create and delete remote data. We also introduce observed properties, observed property groups and a variable handler. Using this mechanism, the BPEL process is able to automatically adapt to changes to data, made inside or outside the process scope, by following the Event, Condition, Action (ECA) paradigm. As a proof-of-concept, we have developed a prototype implementation of our proposed BPEL extensions and tested it by implementing three pilot projects. We have confirmed that our proposed solution decreases BPEL process size and complexity, increases readability and reduces semantic gap between BPMN process model and BPEL.     

High-Level Timed Petri Nets as a kernel for executable specifications

One of the goals of the IPTES environment is to provide a highly usable and formally based specification support environment for real-time applications. Therefore the environment is built upon a formal language that provides a sound, and mathematically well-defined kernel for IPTES. The language provides a means for formulating unambiguous specifications that can be formally verified at any stage of the project. The ability of verifying the specifications from the early stages of the project is very important for revealing errors when their correction can be done at a much lower cost compared with the cost of removing the same errors in later phases.The formal kernel of IPTES is a class of high-level Petri nets, called HLTPNs (High-Level Timed Petri Nets), that allow specifications to be executed, simulated, tested and formally proved.HLTPNs come in two forms: the internal form (HLTPN _i ) and the abstract form (HLTPN _a ).HLTPN _i may be viewed as the machine language of the abstract machine underlying the IPTES environment.HLTPN _a provides a higher-level intermediate notation that allows to deal explicitly with aspects related to scheduling of the modeled system.This material is based upon work supported by the esprit project IPTES and by CNR—Progetto Finalizzato Sistemi Informatici e Calcolo Parallelo.     

Automatic generation of finite element network for groundwater modelling

Bi-dimensional and quasi-three-dimensional FE networks for geological applications are generated starting from digitalised network generation maps. Information contained in the digitalised network generation maps comprises both grid density and selected geological contours that must be matched by sequences of generated network element sides. No limitation is imposed on the grid density distribution. Automatic network grading among areas of different grid density is provided without any additional information. All the generated elements have a good shape which warrants the stability of the calculation. Automatic attribution of geological parameters to the elements and nodes of the grid is done by means of an algorithm to decode digitalised parameter maps.     

Code generation using an orthogonal model

This paper describes a new systematic approach to code generation. The approach is based on an orthogonal model, in which implementation of language-level operators (‘operators’) and addressing operators (‘operands’) is achieved by two independent subtasks. Each of these phases is specified using a set of decision trees that encode the set of possible implementation templates for each language feature and the set of constraints under which each can be applied. Code selection in each phase is achieved by interpreting these trees using a single comprehensive selection algorithm. The method easily extends to machine independence across a large class of target computers by abstracting the implementation templates into machine-independent implementation strategies. The selection algorithm is then modified to select between implementation strategies based on a machine capability ‘menu’ that describes each target machine in terms of the subset of implementation strategies for which it has corresponding instruction sequences. The method has been used to implement a prototype machine-independent code generator for the Concurrent Euclid programming language whose generated code density is consistently within four per cent of production machine-dependent code generators across its entire target class of five modern computers.     

AADL模型代码自动生成技术研究*

随着嵌入式系统在安全关键领域的广泛应用,必须采用现代软件工程的技术进一步提高其可信性,以保证人们的生命安全。基于模型驱动方法,对AADL（体系结构分析设计语言）模型的框架代码自动生成技术进行了研究,提出了从AADL模型元素到C和Ada的语法元素的映射规则,由此实现了自动代码生成器generator并集成在开源工具OSATE中。最后通过一个实例,说明将AADL模型自动转换为框架代码后与模块代码结合的有效性。     

可执行程序缺陷函数的静态检测方法

可执行程序的缺陷函数检测是软件漏洞发现的重要技术手段之一。从二进制代码指令流的角度出发,研究了缺陷函数的签名机制,提出了一种基于可执行程序静态分析的缺陷函数检测方法。该方法通过静态分析应用程序的可执行代码,建立进程运行过程中可能的函数调用序列集合。以该集合为基础,通过对比分析缺陷函数签名,可以准确检测该程序调用的缺陷函数集合,以及分析可能导致的脆弱性。通过实验分析,验证了该方法对于缺陷函数检测的有效性。