Standard ML is a major revision of earlier dialects of the functional language ML. We describe the first compiler written for Standard ML in Standard ML. The compiler incorporates a number of novel features and techniques, and is probably the largest system written to date in Standard ML. Great attention was paid to modularity in the construction of the compiler, leading to a successful large-scale test of the modular capabilities of Standard ML. The front end is useful for purposes other than compilation, and the back end is easily retargetable (we have code generators for the VAX and MC68020). The module facilities of Standard ML were taken into account early in the design of the compiler, and they particularly influenced the environment management component of the front end. For example, the symbol table structure is designed for fast access to opened structures. The front end of the compiler is a single phase that integrates parsing, environment management, and type checking. The m...

Programmable processors offer a high degree of flexibility and are therefore increasingly being used in embedded systems. We introduce the formalism nML which is especially suited to describe such processors in terms of their instruction set, an nML description is directly related to the standard description as found in the usual programmer's manuals. The nML formalism is based on a mixed structural and behavioural model facilitating exact yet concise descriptions. The philosophy of nML is already applied in two approaches to retargetable code generation and instruction set simulation. 1 Introduction In consumer electronics and telecommunications high product volumes are increasingly combined with short life-times and high system complexity. The pressure on development times together with the demand to react on late specification changes make mask or field programmability a desired feature. The thereby obtained flexibility not only helps to shorten the design cycle, but also allows fo...

Ordered, labeled trees are trees in which each node has a label and the left-to-right order of its children (if it has any) is fixed. Such trees have many applications in vision, pattern recognition, molecular biology, programming compilation and natural language processing. Many of the applications involve comparing trees or retrieving/extracting information from a repository of trees. Examples include classification of unknown patterns, analysis of newly sequenced RNA structures, semantic taxonomy for dictionary definitions, generation of interpreters for nonprocedural programming languages, and automatic error recovery and correction for programming languages. Previous systems use exact matching (or generalized regular expression matching) for tree comparison. This paper presents a system, called Approximate-Tree-By-Example (ATBE), which allows inexact matching of trees. The ATBE system interacts with the user through a simple, but powerful query language; graphical devices a...

Relational database systems and most objectoriented database systems provide support for queries. Usually these queries represent retrievals over sets or multisets. Many new applications for databases, such as multimedia systems and digital libraries, need support for queries on complex bulk types such as lists and trees. In this paper we describe an object-oriented query algebra for lists and trees. The operators in the algebra preserve the ordering between the elements of a list or tree, even when the result list or tree contains an arbitrary set of nodes from the original tree. We also present predicate languages for lists and trees which allow order-sensitive queries because they use pattern matching to examine groups of list or tree nodes rather than individual nodes. The ability to decompose predicate patterns enables optimizations that make use of indices.

When developing software for embedded systems, the set of essential tools includes a compiler and an instruction set simulator. Since software and hardware are often designed in parallel, the tools must be easily adaptable to the changing target architecture. For the compiler, its back-end (the code generator) must be retargetable. Abstraction from the target machine is the key to an automated approach. Additionally, abstraction from tool-internal strategies permits the utilization of a unified machine description for all tools. In this chapter, the machine description formalism nML is presented along with the retargetable code generator Cbc and the instruction set simulation environment Sigh/Sim. 1 INTRODUCTION For the realization of retargetable software development tools such as a code generator and an instruction set simulator, several aspects of the potential target machines must be modeled in an abstract manner. These machine models are necessary to formalize the tool's methods...

In many modern designs, timing is either a key optimization goal and/or a mandatory constraint. We propose the first intellectual property protection technique using watermarking that guarantees preservation of timing constraints by judiciously selecting parts of the design specification on which watermarking constraints can be imposed. The technique is applied during the mapping of logical elements to instances of realization elements in a physical library. The generic technique is applied to two steps in the design process: combinational logic mapping in logic synthesis and template matching in behavioral synthesis. The technique is fully transparent to the synthesis process, and can be used in conjunction with arbitrary synthesis tools. Several optimization problems associated with the application of the technique have been solved. The effectiveness of the technique is demonstrated on a number of designs at both logic synthesis and behavioral synthesis. 1.

The Sethi-Ullman algorithm for register allocation finds an optimal ordering of a computation tree. Two simple generalizations of the algorithm increase its applicability without significantly increasing its cost.

Dynamic programming allows locally optimal instruction selection for expression trees. More importantly, the algorithm allows concise and elegant specification of code generators. Aho, Ganapathi, and Tjiang have built the Twig code-generator-generator, which produces dynamic-programming code-generators from grammar-like specifications. Encoding a complex architecture as a grammar for a dynamic-programming codegenerator -generator shows the expressive power of the technique. Each instruction, addressing mode, register and class can be expressed individually in the grammar. The grammar can be factored much more readily than with the Graham-Glanville LR(1) algorithm, so it can be much more concise. Twig specifications for the VAX and MC68020 are described, and the corresponding code generators select very good (and under the right assumptions, optimal) instruction sequences. Limitations and possible improvements to the specification language are discussed. 1. Introduction One of the last...

Code generation influences the efficiency of not only the compiled program but also the compilation process. The appearence of the many new processors has created the need of automating the code generation phase. The instruction selection is a important component to be poduced automatically in the code generation phase. The tools for automating the instruction selection usually use the tree-structure to represent the intermediate representation. The algorithms to manipulate the tree structure are simple. And the powerful tree rewriting tools can be automatically generated for transforming trees to target machine code. Among many technologies for the aumatic generation, BURS technology produces the fastest code generators. But, BURS technology often require long time and much space to process a complex machine description. Much efforts has gone to make BURS technology more attractive: efficient in points of time and space. In this proposal, we closely inspect BURS technology and propose...