EVM Tracer

Advanced transaction debugger and gas optimizer using Geth as a library.

Features

• Custom EVM Tracer: Implements vm.EVMLogger to track opcode execution
• Gas Optimization Detection: Identifies redundant operations and expensive patterns
• Deep Analysis: Storage access, memory operations, external calls, per-opcode gas usage
• CLI Interface: Color-coded output with severity levels and JSON export

Installation

git clone https://github.com/devlongs/evm-tracer
cd evm-tracer
go build -o evm-tracer .

Or use the Makefile:

make build

Usage

# Basic usage
./evm-tracer trace 0xTRANSACTION_HASH

# With custom RPC
./evm-tracer trace 0xTX_HASH --rpc https://mainnet.infura.io/v3/YOUR_KEY

# Verbose output with gas breakdown
./evm-tracer trace 0xTX_HASH --verbose

# JSON export
./evm-tracer trace 0xTX_HASH --json > report.json

Example Output

═══════════════════════════════════════════════════════════════
           EVM TRACER - GAS OPTIMIZATION REPORT
═══════════════════════════════════════════════════════════════

📊 Total Gas Used: 125.43K
🔍 Optimizations Found: 4

🚨 HIGH PRIORITY OPTIMIZATIONS

1. redundant_sload
   Description: Multiple SLOAD operations for the same storage slot
   💰 Potential Savings: 300 gas
   Details:
     • read_count: 4
     • storage_key: 0xabcd...

💰 Total Potential Savings: 2.10K (~1.67%)

Architecture

cmd/              CLI commands (root, trace)
internal/
  tracer/         Custom EVM tracer implementation
  analyzer/       Transaction replay and Geth integration
  formatter/      Output formatting (console, JSON)

How It Works

1. Tracer implements vm.EVMLogger interface to hook into EVM execution
2. Analyzer fetches transaction data and replays it with the custom tracer
3. Formatter presents findings with color-coded severity levels

Detected Optimizations

High Priority

• Redundant SLOAD operations (~100 gas/read)
• Repeated storage writes to same slot (~2,900+ gas)

Medium Priority

• Expensive opcodes (CREATE, KECCAK256, LOG)
• Multiple external calls (batch for ~2,100 gas savings)
• Memory expansion (quadratic cost)

Low Priority

• Inefficient gas forwarding patterns

Testing

# Run tests
go test ./internal/tracer/ -v

# Test with local node
npx hardhat node  # Terminal 1
./evm-tracer trace 0xTX_HASH  # Terminal 2

# Test with mainnet
./evm-tracer trace 0xTX_HASH --rpc https://mainnet.infura.io/v3/YOUR_KEY

Requirements

• Go 1.21+
• Ethereum RPC node (local or remote)

License

MIT - see LICENSE