Georg Winterstein

An attribute grammar for Ada

We describe the development of a formal specification of the static semantics of Ada in form of an attribute grammar. This specification is complete, and was tested extensively with automatically generated equivalent Pascal programs. From this specification we systematically developed the semantic analysis part of our Ada Compiler Front End. We outline the general proceeding when specifying semantic analysis with attribute grammars and then discuss to some extent examples about declaration elaboration and overloading resolution. CR Categories and Subject Descriptors: D.3.1 [Programming Languages]: Formal definitions and Theory - semantics; D.3.4 [Programming Languages]: Processors - Translator writing systems and compiler generators; F.3.2 [Logics and Meanings of Programs]: Semantics of Programming Languages - algebraic approaches to semantics.

Overloading in preliminary Ada

Ada permits the overloading of enumeration literals, aggregates, subprograms and operators, i.e. the declaration of the same designator with different meanings in the same scope. This leads to difficulties during the semantic analysis of expressions and subprogram calls. For selecting the meaning not only the designator but also the types of its operands or parameters and the type of its result must be used. We show that the identification of expressions is possible in two passes, the first bottom-up, the second top-down.

An LALR (1) grammar for (revised) Ada

In transforming the initial grammar given in [R-ADA] first all obvious ambiguities have been removed. Most of them arise from the use of the nonterminal type mark which is equivalent to name. The more severe LALR([) conflicts are the identifier list in declarations, indexed names and similiar constructs, the sequencing in declarative parts [Cro], subprogram bodies and instantiations, and entry names in accept statements.

A Separate Compilation System for Ada

The programming language Ada provides a concept for the separate compilation of program units where checks have to be done across the unit bounds at compile time. Here we describe the Separate Compilation System which was developed for the Ada Compiler Project at the University of Karlsruhe. The realization of the separate compilation facility of Ada is mainly based on the use of a library which contains information about previously compiled units. The separate compilation system maintains the library and provides the functions to support the compiler and other programming tools.

Towards a compiler front-end for Ada

This paper discusses the current development of a compiler front-end for Ada at the University of Karlsruhe. The front-end is independent of the target-machine and will compile Ada into an intermediate language AIDA, essentially an attributed structure tree. The front-end is written in its own language using Ada-0 and LIS as preliminary compilers for the bootstrap. The compiler in its present form relies heavily on the formal definition of Ada which is under development at CII and IRIA.

Problems in Compiling Ada

Ada is a new system programming language designed by Jean D. Ichbiah et al. on behalf of the American DoD. We outline the structure of a compiler for Ada, subdivided into a (machine-independent) front-end and machine-dependent back-ends. Then we discuss the methods which we applied to solve the problems arising in the design of the front-end. Finally we give a short overview over the intermediate language DIANA which has been specifically designed to represent Ada programs in intermediate form.

LIS as Object Code for an ADA-O-Compiler

In this paper we examine the translation of a subset of ADA into LIS. The subset provides enough facilities to write an ADA compiler in it. Comparing ADA and LIS the subset is specified by those language elements both languages have in common.

A Method for Describing Concurrent Problems Based on Logic

In this talk we investigate the usefulness of logic programming for the description of concurrent problems. A logic program consists of an axiomatization of the problem domain together with the specification of a certain control. To describe the axiomatization only a restricted form of predicate logic is used which is known as Horn clauses. For this class a “procedural interpretation” can be given. The control specification determines in which way procedure invocations should be executed. Synchronization of processes can be obtained with the help of a data structure the processes have in common.