Types of Three-Address Code Statements & Expressions

Lecture 38 of CS606 Compiler Construction catalogs the universal instruction set comprising Three-Address Code. To represent the full expressive semantics of modern programming languages, 3AC defines standardized statement types: Binary Assignments (x = y op z), Unary Assignments (x = op y), Copy Instructions (x = y), Unconditional Jumps (goto L), Conditional Branches (if x relop y goto L), Procedure Calls and Parameter Passing (param x followed by call p, n), Return Statements (return y), Indexed Assignments (x = y[i] and x[i] = y), and Pointer Indirection Operations (x = &y, x = *y, and *x = y). Students practice generating complete 3AC instruction sequences for complex mathematical calculations, array element lookups involving base addresses and row-major displacement formulas, and function invocation protocols with stack activation records. Intermediate representation taxonomy categorizes structural formats into graphical ASTs, linear tuples, and hybrid tree-address models. The strategic role of peephole optimization is evaluated as a final localized pass to eliminate redundant loads, stores, and jumps. In this lecture, students examine formal language translation principles and architectural compiler pipelines to understand automated code generation. Through detailed theoretical derivations and algorithmic walkthroughs, the lesson explores lexical tokenization, grammatical parse trees, and syntax trees. Special emphasis is placed on formal grammar transformations, eliminating left recursion, and establishing unambiguous predictive parsing tables. Mastering these foundational language translation frameworks empowers computer science scholars to design robust parsers, interpreters, and domain-specific languages. Analytical exercises, state transition diagrams, and solved numerical problems help students prepare thoroughly for Virtual University midterm and final term examinations. The curriculum systematically bridges abstract automata theory with concrete systems programming techniques and modern compiler construction tools. Reviewing the accompanying lecture handouts and structural diagrams reinforces understanding of symbol tables, semantic type checking, and runtime memory layouts. Consistent evaluation of grammatical derivations, item closure sets, and shift-reduce actions ensures robust preparation for academic assessments. Students investigate the role of intermediate representations in decoupling front-end language syntax from target machine instruction architectures.