[ Source Code ] │ ▼ ┌─────────────────────────┐ │ Lexical Analyzer │ <───> [ Symbol Table ] └─────────────────────────┘ │ Tokens ▼ ┌─────────────────────────┐ │ Syntax Analyzer │ <───> [ Symbol Table ] └─────────────────────────┘ │ Parse Tree ▼ ┌─────────────────────────┐ │ Semantic Analyzer │ <───> [ Symbol Table ] └─────────────────────────┘ │ Decorated Tree ▼ ┌─────────────────────────┐ │ Intermediate Code Gen. │ <───> [ Symbol Table ] └─────────────────────────┘ │ Intermediate Code ▼ ┌─────────────────────────┐ │ Code Optimizer │ └─────────────────────────┘ │ Optimized Code ▼ ┌─────────────────────────┐ │ Code Generator │ <───> [ Symbol Table ] └─────────────────────────┘ │ ▼ [ Target Machine Code ] Auxiliary Components
By understanding the core phases and mechanics of a compiler, you can easily secure 100% accuracy in this section. This comprehensive guide breaks down the essential concepts, phase-by-phase workflows, and critical problem-solving shortcuts used by GATE top performers. 1. Introduction to Compiler Design
Tokenization, Regular Expressions, Finite Automata. compiler design gate smashers
Loop optimization (Loop Unrolling, Loop Motion), Machine-independent optimization (Constant Folding, Dead Code Elimination, Common Subexpression Elimination). 6. Code Generation
Remember that an ambiguous grammar can never be parsed by any deterministic parser (neither LL(1) nor any member of the LR family). If a grammar is ambiguous, immediately rule out these options. Unlike an interpreter
Focus on LL(1) grammars. Master the algorithmic calculation of FIRST and FOLLOW sets. Understand the conditions for a grammar to be LL(1) (no left recursion, no left factoring).
Unlike an interpreter, which translates and executes code line-by-line, a compiler analyzes the entire program first. It generates an executable file, making the final execution much faster, though the initial compilation takes time. Structure of a Compiler: The Phases which translates and executes code line-by-line
Shift (push token to stack), Reduce (replace substring with a non-terminal), Accept , and Error .
Minimizes optimization overhead by using separate pointer arrays to reference an underlying Triples table, allowing code reordering without renaming indices. 7. Code Optimization Techniques
To generate code for a = b + c (assuming ADD instruction):