is the second phase of a compiler. A syntax analyzer or parser takes the input from a lexical analyzer in the form of token streams. The parser analyzes the source code (token stream) against the production rules to detect any errors in the code. Parsing is one of the most critical parts of compiler design. You need to learn the differences between LL(1), LR(0), SLR, LALR, and CLR parsers . Practice building parse trees and identifying the grammars they support, as these topics frequently appear in GATE questions.
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)
Maps the optimized intermediate code to the actual target machine language or assembly code. It handles register allocation and assignment. compiler design gate smashers
What is stored in the activation record for a recursive function? – Control link, access link, locals, temps.
Canonical LR. Incorporates explicit lookahead symbols inside the LR items. Highly powerful but creates massive parsing tables. is the second phase of a compiler
Manages memory dynamically using an Activation Record (Stack Frame) pushed onto a runtime stack whenever a function is called, and popped when it returns. This framework naturally supports recursion.
Resource allocation, register assignment, and instruction scheduling. 7. Symbol Table & Error Handler Parsing is one of the most critical parts of compiler design
┌──────── Parsing ────────┐ │ │ ▼ ▼ ┌── Top-Down Parsers ──┐ ┌── Bottom-Up Parsers ──┐ │ │ │ │ Backtracking Non-Backtracking Shift-Reduce LR Parsers (Brute Force) LL(1) │ ┌───────────────────────┼──────────┐ ▼ ▼ ▼ LR(0) / SLR(1) LALR(1) CLR(1) High-Yield Parsing Matrix Parser Type Parsing Table Relations Conflict Triggers Capability / Power Match Terminal / Non-Terminal Left Recursion, Left Factoring Weakest Top-Down LR(0) Uses LR(0) State Items Shift-Reduce (S-R), Reduce-Reduce (R-R) Weakest Bottom-Up SLR(1) Uses Follow() Set for Reductions S-R, R-R based on Follow set Moderate Power LALR(1) Merges Identical Core LR(1) States Can introduce R-R conflicts Most Practical (YACC/Bison) CLR(1) Uses Explicit Lookaheads None (Handles all deterministic CFGs) Most Powerful / Largest Table 🏷️ Phase 3: Semantic Analysis (Type Checking)
In this post, we will explore how compiler design works to "smash" these gates, transforming branching logic into straight-line, blazing-fast machine code.
Invoked whenever a phase encounters an anomaly, ensuring the compiler provides clear debugging feedback to the programmer. 2. Lexical Analysis: Tokens and Regular Expressions
Understand how semantic rules are evaluated using attributes: