Basic blocks and flow graphs in Compiler Design - Mini Project: Build & Apply

Understanding Basic Blocks and Flow Graphs

📖 Scenario: You are learning how compilers organize code into basic blocks and represent program flow using flow graphs. This helps in understanding how programs execute step-by-step.

🎯 Goal: Build a simple representation of basic blocks and create a flow graph showing how these blocks connect.

📋 What You'll Learn

Create a list of basic blocks with exact given instructions

Define a dictionary representing edges between blocks

Use a loop to display connections between blocks

Add a final summary line describing the flow graph

💡 Why This Matters

🌍 Real World

Compilers use basic blocks and flow graphs to analyze and optimize code execution paths.

💼 Career

Understanding these concepts is essential for compiler developers, software engineers working on performance optimization, and anyone interested in how programs run internally.

1

Create Basic Blocks List

Create a list called basic_blocks with these exact strings as elements in order: 'Block1: start', 'Block2: condition check', 'Block3: true branch', 'Block4: false branch', 'Block5: end'.

Compiler Design

# Create the list basic_blocks with the specified block names
# Your code here

Need a hint?

Use square brackets to create a list and include all block names as strings separated by commas.

2

Define Flow Graph Edges

Create a dictionary called flow_graph where keys are block names from basic_blocks and values are lists of blocks they connect to. Use these exact connections: 'Block1: start' connects to 'Block2: condition check', 'Block2: condition check' connects to 'Block3: true branch' and 'Block4: false branch', 'Block3: true branch' and 'Block4: false branch' both connect to 'Block5: end', and 'Block5: end' connects to an empty list.

Compiler Design

basic_blocks = ['Block1: start', 'Block2: condition check', 'Block3: true branch', 'Block4: false branch', 'Block5: end']
# Create the flow_graph dictionary with the specified connections
# Your code here

Need a hint?

Use curly braces to create a dictionary. Each key is a block name string, and each value is a list of connected block names.

3

Display Flow Graph Connections

Use a for loop with variables block and connections to iterate over flow_graph.items(). Inside the loop, create a string called connection_str that joins connections with ' -> '. Then create a string called output_line that shows the format: "{block} connects to: {connection_str}". Assign output_line inside the loop.

Compiler Design

basic_blocks = ['Block1: start', 'Block2: condition check', 'Block3: true branch', 'Block4: false branch', 'Block5: end']
flow_graph = {
    'Block1: start': ['Block2: condition check'],
    'Block2: condition check': ['Block3: true branch', 'Block4: false branch'],
    'Block3: true branch': ['Block5: end'],
    'Block4: false branch': ['Block5: end'],
    'Block5: end': []
}

# Use a for loop to create output_line strings showing connections
# Your code here

Need a hint?

Use for block, connections in flow_graph.items(): to loop. Use ' -> '.join(connections) to join connected blocks.

4

Add Flow Graph Summary

Create a string variable called summary and assign it the exact text: 'This flow graph shows how basic blocks connect in a program.'.

Compiler Design

basic_blocks = ['Block1: start', 'Block2: condition check', 'Block3: true branch', 'Block4: false branch', 'Block5: end']
flow_graph = {
    'Block1: start': ['Block2: condition check'],
    'Block2: condition check': ['Block3: true branch', 'Block4: false branch'],
    'Block3: true branch': ['Block5: end'],
    'Block4: false branch': ['Block5: end'],
    'Block5: end': []
}

for block, connections in flow_graph.items():
    connection_str = ' -> '.join(connections)
    output_line = f"{block} connects to: {connection_str}"

# Add the summary string below
# Your code here

Need a hint?

Assign the exact text to a variable named summary.