Implementation of CSP-S for description of distributed algorithms

The implementation of CSP-S (a subset of CSP)—a high level language for distributed programming—is presented in this paper. The language CSP-S features a parallel command, communication by message passing and the use of guarded command. The implementation consists of a compiler translating the CSP-S constructs into intermediate language. The execution is carried out by a scheduler which creates an illusion of concurrency. Using the CSP-S language constructs, distributed algorithms are written, executed and tested with the compiler designed.     

Adam: An Ada-based language for multiprocessing

Adam is a high-level language for parallel processing. It is intended for programming resource scheduling applications, in particular supervisory packages for run-time scheduling of multiprocessing systems. An important design goal was to provide support for implementation of Ada and its run-time environment. Adam has been used to implement Ada task supervision and also as a high-level target language for compilation of Ada tasking. Adam provides facilities corresponding to the Ada sequential constructs (including subprograms, packages, exceptions, generics). In addition, it provides specialized module constructs for implementation of packages that may be shared between parallel processes, and new predefined types for scheduling. The parallel processing constructs of Adam are more primitive than Ada tasking. Strong restrictions are enforced on the ways in which parallel processes can interact. A compiler for Adam has been implemented in MacLisp on DEC PDP-10 computers. Runtime support packages in Adam for scheduling (on a single CPU) and I/O are also provided. The compiler contains a library manipulation facility for separate compilation. The Adam compiler has been used to build an Ada compiler for most of the July 1980 Ada, including task types and rendezvous constructs. This was achieved by implementing the translation of Ada tasking into Adam parallel processing as a preprocessor to the Adam compiler. This present Ada compiler, which has been operational since December 1980, uses a procedure call implementation of tasking. It can be easily modified to other implementations. Compilation of Ada tasking into a high-level target language such as Adam facilitates studying questions of correctness and efficiency of various compilation algorithms, and code optimizations specific to tasking, e.g. elimination of unnecessary threads of control. This paper gives an overview of Adam and examples of its use. Emphasis is placed on the differences from Ada. Experience using Adam to build the experimental Ada system is evaluated. Design of a run-time supervisor in Adam is discussed in detail.     

Optimizing compiler for the procedural subset of the algebraic programming language of the APS system

Conclusion An L2B-L2C optimizing compiler has been developed for compiling the procedural subset of the interpreted untyped language APLAN of the algebraic programming system APS into C. Controlled automatic compiling of procedures is regarded as a technological step toward efficient solution of problems in an algebraic programming environment. A distinctive feature of the compiler is that optimization is initiated by the user and relies on hierarchical algebraic specifications. If no specifications are present, the system guarantees compilation consistent with common APLAN semantics. The compiler is formally described on two levels. On the architectural level, we describe the general structure of the compiling process. The main data structures used for optimization are dictionaires of algebraic program components and expression type arrays. The semantic level of multialternative compiling of language constructs is represented in the language of relationships with selection of an appropriate translation alternative. The implementation of the proposed compiler requires a flexible support environment, which allows nonhomogeneous processing of an extended source language, in particular construction of static and dynamic information environments, compilation of the procedural part, and also analysis of the compiling environment, definition of the set of translations of procedural constructs, and selection of the best translation alternative for each particular case. An implementation of the proposed compiler is described in [13]. Translated from Kibernetika i Sistemnyi Analiz, No. 6, pp. 3–16, November–December, 1995.     

Normal form approach to compiler design

This paper demonstrates how reduction to normal form can help in the design of a correct compiler for Dijkstra's guarded command language. The compilation strategy is to transform a source program, by a series of algebraic manipulations, into a normal form that describes the behaviour of a stored-program computer. Each transformation eliminates high-level language constructs in favour of lower-level constructs. The correctness of the compiler follows from the correctness of each of the algebraic transformations.     

ILX: Extending the .NET Common IL for Functional Language Interoperability

This paper describes several extensions to the .NET Common Intermediary Language (CIL), each of which is designed to enable easier implementation of typed high-level programming languages on the .NET platform, and to promote closer integration and interoperability between these languages. In particular we aim for easier interoperability between components whose interfaces are expressed using function types, discriminated unions and parametric polymorphism, regardless of the languages in which these components are implemented. We show that it is possible to add these constructs to an existing, “real world” intermediary language and that this allows corresponding subsets of constructs to be compiled uniformly, which in turn will allow programmers to use these constructs seamlessly between different languages. In this paper we discuss the motivations for our extensions, which are together called Extended IL (ILX), and describe them via examples. In this setting, many of the traditional responsibilities of the backend of a compiler must be moved to ILX and the execution environment, in particular those related to representation choices and low-level optimizations. We have modified a Haskell compiler to generate this language, and have implemented an assembler that translates the extensions to regular or polymorphic CIL code.I am very grateful to Nick Benton, Cedric Fournet, Andrew Kennedy, Andy Gordon, Simon Peyton Jones, Claudio Russo, Reuben Thomas, Andrew Tolmach and the anonymous referees for their help and advice with this work.     

AspectLISA: An Aspect-oriented Compiler Construction System Based on Attribute Grammars

The use of object-oriented techniques and concepts, like encapsulation and inheritance, greatly improves language specifications towards better modularity, reusability and extensibility. Additional improvements can be achieved with aspect-oriented techniques since semantic aspects also crosscut many language constructs. Indeed, aspect-oriented constructs have been already added to some language specifications. The LISA compiler construction system follows an object-oriented approach and has already implemented mechanisms for inheritance, modularity and extensibility. Adding aspects to LISA will lead to more reusable language specifications. In the paper, aspect-oriented attribute grammars are introduced, and the underlying ideas are incorporated into AspectLISA, an aspect-oriented compiler generator based on attribute grammars.     

A statistical analysis of syntax errors

A study of errors made by Pascal programmers is described. The results of this study are discussed in relation to compiler syntax error recovery procedures. It is found that syntax errors made in practice are quite simple and occur relatively infrequently (generally at most one per sentence of the language). Also a few types of errors account for most occurrences. These and other findings from the study are helpful in evaluating compiler error handling procedures. A discussion of the relation between these errors and language constructs is presented. Other uses of the information obtained from the study are briefly described.     

Compiler Verification and Compiler Architecture

We study issues in verifying compilers for modern imperative and object-oriented languages. We take the view that it is not the compiler but the code generated by it which must be correct. It is this subtle difference that allows for reusing standard compiler architecture, construction methods and tools also in a verifying compiler.Program checking is the main technique for avoiding the cumbersome task of verifying most parts of a compiler and the tools by which they are generated. Program checking remaps the result of a compiler phase to its origin, the input of this phase, in a provably correct manner. We then only have to compare the actual input to its regenerated form, a basically syntactic process. The correctness proof of the generation of the result is replaced by the correctness proof of the remapping process. The latter turns out to be far easier than proving the generating process correct.The only part of a compiler where program checking does not seem to work is the transformation step which replaces source language constructs and their semantics, given, e.g., by an attributed syntax tree, by an intermediate representation, e.g., in SSA-form, which is expressing the same program but in terms of the target machine. This transformation phase must be directly proven using Hoare logic and/or theorem-provers. However, we can show that given the features of today's programming languages and hardware architectures this transformation is to a large extent universal: it can be reused for any pair of source and target language. To achieve this goal we investigate annotating the syntax tree as well as the intermediate representation with constraints for exhibiting specific properties of the source language. Such annotations are necessary during code optimization anyway.     

The Fork95 parallel programming language: Design, implementation, application

Fork95 is an imperative parallel programming language intended to express algorithms for synchronous shared memory machines (PRAMs). It is based on ANSI C and offers additional constructs to hierarchically divide processor groups into subgroups and manage shared and private address subspaces. Fork95 makes the assembly-level synchronicity of the underlying hardware available to the programmer at the language level. Nevertheless, it supports locally asynchronous computation where desired by the programmer. We present a one pass compiler, fcc, which compiles Fork95 and C programs to the SB-PRAM machine. The SB-PRAM is a lock-step synchronous, massively parallel multiprocessor currently being built at Saarbrücken University, with a physically shared memory and uniform memory access time. We examine three important types of parallel computation frequently used for the parallel solution of real-world problems. While farming and parallel divide-and-conquer are directly supported by Fork95 language constructs, pipelining can be easily expressed using existing language features; an additional language construct for pipelining is not required.     

Survey of compiler testing methods

Compilers are used for creating executable modules for programs written in high-level languages; therefore, the presence of errors in a compiler is a serious danger for the quality of the software developed with the use of this compiler. As in the case of any other software, testing is one of the most important methods of quality control and error detection in compilers. The survey is devoted to methods for generating, running, and checking the quality of compiler test suites, which are based on formal specifications of the programming language syntax and semantics.Translated from Programmirovanie, Vol. 31, No. 1, 2005.Original Russian Text Copyright © 2005 by Kossatchev, Posypkin.     

Stress testing of compilers for modula-2

During standardization discussions on Modula-2 the question was raised whether the future standard should need a clause stating a set of minimal requirements for conforming implementations regarding the ‘structuredness’ of lexical, syntactical and run-time constructs in programs written in this language. It was decided to test a number of compilers to find their actual limits on the structuredness of some of these constructs. The test results do not only show these limits, but the inability of some compilers to handle large and complex inputs is shown as well.     

嵌入式C02语言编译器的设计与实现*

介绍了一种用于嵌入式处理器Si02的高级语言编译器的设计与实现方法。提出了处理器Si02特有的寄存器分配方法——循环栈机制,并给出了编译器关键技术中的一些算法,简化了嵌入式编译器的实现过程。     

The Design and Implementation of a Domain-Specific Language for Network Performance Testing

CONCEPTUAL is a toolset designed specifically to help measure the performance of high-speed interconnection networks such as those used in workstation clusters and parallel computers. It centers around a high-level domain-specific language, which makes it easy for a programmer to express, measure, and report the performance of complex communication patterns. The primary challenge in implementing a compiler for such a language is that the generated code must be extremely efficient so as not to misattribute overhead costs to the messaging library. At the same time, the language itself must not sacrifice expressiveness for compiler efficiency, or there would be little point in using a high-level language for performance testing. This paper describes the CONCEPTUAL language and the CONCEPTUAL compiler's novel code-generation framework. The language provides primitives for a wide variety of idioms needed for performance testing and emphasizes a readable syntax. The core code-generation technique, based on unrolling CONCEPTUAL programs into sequences of communication events, is simple yet enables the efficient implementation of a variety of high-level constructs. The paper further explains how CONCEPTUAL implements time-bounded loops - even those that comprise blocking communication - in the absence of a time-out mechanism as this is a somewhat unique language/implementation feature.     

An algol-like assembly language for a small computer

In a classic paper¹ Wirth describes a language which combines the readability of ALGOL 60 with the flexibility and degree of control of a conventional assembly language. This paper gives an outline of a similar language for a small 16-bit computer—the Honeywell DDP-516. Implementing the compiler in its own language by recoding an ALGOL version of the compiler has shown that the language is suitable for large systems. With the compiler written in a high-level language, many enhancements have been possible even though these were not envisaged in the original coding This use of the language clearly demonstrated that a high-level assembly language can be a very effective tool for a small machine as well as for computers like the 360 series.     

P3 L: A structured high-level parallel language,and its structured support

The paper presents a parallel programming methodology that ensures easy programming, efficiency and portability of programs to different machines belonging to the class of the general-purpose, distributed-memory, MIMD architectures. The methodology is based on the definition of a new, high-level, explicitly parallel language, called P³ L, and of a set of static tools that automatically adapt the program features for each target architecture. P³ L does not require programmers to specify process activations, the actual parallelism degree, scheduling, or interprocess communications, i.e. all those features that need to be adjusted to harness each specific target machine. Parallelism is, on the other hand, expressed in a structured and qualitative way, by hierarchical composition of a restricted set of language constructs, corresponding to those forms of parallelism that are frequently encountered in parallel applications, and that can be efficiently implemented. The efficient portability of P³ L applications is guaranteed by the compiler along with the novel structure of the support. The compiler automatically adapts the program features for each specific architecture, using the costs (in terms of performance) of the low-level mechanisms exported by the architecture itself. In our methodology, these costs, along with other features of the architecture, are viewed through an abstract machine, whose interface is used by the compiler to produce the final object code.     

数据流语言简化并行编程

由于当前硬件的开发逐日增加,为了充分发挥这些硬件的功能,通过介绍数据流编程语言的应用方式,一同介绍了数据流语言所充分利用的类似流程图的用法.利用智能编译器进行检测程序过程,陈述了与硬件地址相结合的编程方法.这种方法极大地简化了开发人员编写多线程程序的难处,同时能够充分发挥多棱CPU的效率.     

A Data-Parallel FP Compiler

In data-parallel programming, operations are performed simultaneously on all elements of large data structures. Backus′s FP functional language promotes this view. FP provides a large set of data rearrangement primitives, and a useful set of functional combining forms that are applied to entire data structures. We describe an FP compiler that generates programs capable of exploiting data-parallelism. The FP compiler deduces the type and shape of objects through type inference, and generates efficient parallel implementations of combining forms. In addition, the compiler determines the effects of data rearrangement functions at compile-time, thereby avoiding creation of large intermediate data structures, and reducing interprocessor communication overhead. FP and its compiler are formally specified, reducing ambiguity concerning constructs of the language and results of the compiler. Performance and speed-ups achieved from our compilation and optimization techniques are demonstrated with timings from a prototype implementation on the Connection Machine CM-2.     

A demonstrably correct compiler

As critical applications grow in size and complexity, high level languages, rather than better-trusted assembly languages, will be used in their development. This adds potential for extra errors to creep in, especially in the now necessary compiler. To avoid these new errors, it is necessary to have a formal specification of the high level language, and a formal development of its compiler. We outline what we believe is a practical route for achieving a demonstrably correct compiler, and describe a prototype compiler we have built by this route for a small, but non-trivial, language.