C++ Compilation Overview

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The Compilation Pipeline

Every C++ program goes through multiple transformation stages before becoming executable machine code. This overview shows the complete pipeline:

C++ Compilation Pipeline

Source Code

main.cpp

Preprocessing

main.i

Parsing

AST

Semantic Analysis

Annotated AST

IR Generation

IR

Optimization

Optimized IR

Code Generation

main.s

Assembly

main.o

Typical File Sizes

.cpp

~1KB

.i

~50KB

AST

~20KB

IR

~15KB

.s

~5KB

.o

~2KB

Compilation Stages

Each stage transforms your code closer to machine language:

1. Preprocessing

Macro expansion
Include processing
Conditional compilation
Output: Expanded source (.i file)

2. Parsing & AST

Lexical analysis (tokenization)
Syntax analysis (parsing)
Build Abstract Syntax Tree
Output: AST representation

3. Semantic Analysis

Type checking
Name resolution
Template instantiation
Output: Annotated AST

4. Optimization

Code improvements
Performance enhancements
Size reductions
Output: Optimized IR

5. Code Generation

Target-specific assembly
Register allocation
Instruction selection
Output: Assembly (.s file)

6. Assembly

Convert to machine code
Create object file
Output: Object file (.o)

Quick Commands

# Complete compilation
g++ main.cpp -o program

# Stop after preprocessing
g++ -E main.cpp -o main.i

# Generate assembly
g++ -S main.cpp -o main.s

# Create object file only
g++ -c main.cpp -o main.o

# With optimization
g++ -O2 main.cpp -o program

Compilation Deep Dives

Explore each stage in detail:

📝 Preprocessor Directives - Macros and includes
🌳 AST & Parsing - Code structure analysis
⚡ Optimization Techniques - Performance improvements
📦 Object Files - Binary format and symbols

What's Next?

After compilation, your object files need to be:

Linked together to resolve symbols
Loaded into memory for execution

Table of Contents

C++ Compilation Pipeline

Typical File Sizes