Compiler Design Gate Smashers ◆ < TRUSTED >

Tokens, Lexemes, Patterns, Regular Expressions. Gate Smashers Focus: How does the compiler break int a = b + 5 into tokens?

A grammar is ambiguous if it can produce more than one parse tree (or more than one LMD/RMD) for a single input string. Ambiguous grammars cannot be used for parsing unless disambiguation rules (like operator precedence) are added. Classification of Parsers Parsers are divided into Top-Down and Bottom-Up approaches:

Use only synthesized attributes (evaluated from children to parent). They are evaluated during bottom-up parsing (LR parsers).

This paper is for educational purposes, modeled after the teaching style of Gate Smashers. All credit to original educators. compiler design gate smashers

Compiler design is a foundational subject in Computer Science, and Gate Smashers

Analyzes and improves the code (e.g., liveness analysis) to make it faster or more resource-efficient. Runtime Environment:

Detects, reports, and recovers from errors encountered during any phase. High-Weightage GATE Topics in Compiler Design Tokens, Lexemes, Patterns, Regular Expressions

SDT attaches semantic rules to the syntax productions to evaluate values or generate code.

Converting expressions into Three-Address Code (TAC), Quadruples, Triples, and Indirect Triples. Syntax trees and Directed Acyclic Graphs (DAG) are highly tested here for minimizing subexpressions. 5. Code Optimization

Pro Tip: Understand the relationship between these. For example, every SLR(1) grammar is also LALR(1) and CLR(1), but not vice versa. Syntax Directed Translation (SDT) Ambiguous grammars cannot be used for parsing unless

Loop optimization, constant folding, common subexpression elimination. 6. Target Code Generator

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Calculating the FIRST() and FOLLOW() sets of non-terminals is mandatory to construct the LL(1) parsing table. 2. Bottom-Up Parsers