From Source Code to Machine Silicon: ASTs, SSA & LLVM Optimization
Compilers are among the most sophisticated software systems ever engineered. They translate human-readable source code into machine code through distinct compilation phases.
1. Lexical Analysis & Abstract Syntax Trees (AST)
- Lexer (Scanner): Converts raw character streams into a token stream (
IDENTIFIER,ASSIGN,NUMBER,SEMICOLON). - Parser: Validates grammar against Context-Free Grammars (CFG) and builds an Abstract Syntax Tree (AST).
2. Static Single Assignment (SSA) Form
Modern optimizing compilers convert ASTs into Static Single Assignment (SSA) intermediate representation (IR), where every variable is assigned exactly once.
SSA unlocks compiler optimizations including:
- Dead Code Elimination (DCE)
- Common Subexpression Elimination (CSE)
- Loop-Invariant Code Motion (LICM)
Learn compiler parsing and tree structures in our AST & Syntax Analysis Target!