FRONT END OF A COMPILER FOR A SUBSET OF PASCAL

Abstract

The front end of a compiler for a subset of Pascal has been constructed using the language development tools - Lex, Yacc and Make, available on the UNIX system. It generates. intermediate code using indirect triple notation. This work is divided into four modules. 1. Lexical analyser 2. Parser 3. Error handler and intermediate code generator 4. Optimizer Lexical analyser is generated by giving a set of regular expressions as input to Lex. Each regular expression is associated with an action routine for installing lexemes in symbol and literal tables. The grammar for the Pascal subset is written and given as input to Yacc, which in turn generates a Parser. -Error handler and intermediate code are implemented by incorporating appropriate action program segments in the grammar rules using Syntax Directed Translation. A comprehensive set of local and global optimizations is performed on the intermediate code to enable an efficient code generation.