Decompile Contracts

A Solidity/Bend-PVM decompiler written in Zig 0.15.2. Analyzes EVM bytecode and RISC-V (Bend-PVM) bytecode to produce human-readable output.

Features

• EVM Disassembly: Convert Ethereum bytecode to human-readable assembly
• Function Selectors: Extract and match known function signatures
• Type Inference: Infer Solidity types from bytecode patterns
• Control Flow Analysis: Generate CFGs and identify functions
• Symbolic Execution: Analyze storage access patterns
• Solidity-like Output: Generate pseudo-Solidity code
• Bend-PVM Support: Detect and disassemble RISC-V bytecode

Installation

# Clone the repository
git clone https://github.com/codingsh/decompile-contracts
cd decompile-contracts

# Build
zig build

# Run
./zig-out/bin/decompile_contracts <bytecode> [options]

Usage

# Basic disassembly
./zig-out/bin/decompile_contracts 0x608060405234801560011f5ffd5b505f80fd5b50634e3f15f3

# Full analysis
./zig-out/bin/decompile_contracts <bytecode> --full

# Specific analysis
./zig-out/bin/decompile_contracts <bytecode> --disasm
./zig-out/bin/decompile_contracts <bytecode> --abi
./zig-out/bin/decompile_contracts <bytecode> --solidity
./zig-out/bin/decompile_contracts <bytecode> --types
./zig-out/bin/decompile_contracts <bytecode> --controlflow
./zig-out/bin/decompile_contracts <bytecode> --symbolic

# Bend-PVM / RISC-V analysis
./zig-out/bin/decompile_contracts <bytecode> --bend

CLI Options

Flag	Description
--disasm	Show disassembly
--abi	Show extracted function selectors
--solidity	Generate Solidity-like code
--types	Show type inference analysis
--controlflow	Show control flow analysis
--symbolic	Run symbolic execution analysis
--bend	Generate Bend-PVM source (RISC-V)
--full	Full analysis (default)

Examples

EVM Bytecode Analysis

./zig-out/bin/decompile_contracts 0x608060405234801560011f5ffd5b505f80fd5b50634e3f15f3

Output:

Detected bytecode type: EVM (Ethereum)

=== Disassembly ===
0000 PUSH1 0x80
0002 PUSH1 0x40
0004 MSTORE
0005 CALLVALUE
...

=== Function Selectors ===
0xa9059cbb -> transfer(address,uint256)
0x23b872dd -> transferFrom(address,address,uint256)
...

Bend-PVM / RISC-V Analysis

./zig-out/bin/decompile_contracts 0x9300500013000000 --bend

Output:

Detected bytecode type: Bend-PVM (RISC-V)

=== Bend-PVM Source Reconstruction ===

pub fn main(x: Int) -> Result {
    // - 4 arithmetic operations
    0
}

Development

Requirements

• Zig 0.15.2

Build

zig build

Test

zig build test

Run

zig build run -- <bytecode> [options]

Project Structure

src/
├── main.zig              # CLI entry point
├── root.zig              # Library exports
├── evm/
│   ├── opcodes.zig       # EVM opcodes (142 opcodes)
│   ├── disassembler.zig  # Bytecode disassembly
│   └── abi.zig           # Function selector extraction
├── bend/
│   ├── opcodes.zig       # RISC-V opcodes
│   └── source.zig        # Bend-PVM source generation
├── symbolic/
│   └── executor.zig      # Symbolic execution engine
└── analysis/
    ├── storage.zig       # Storage layout analysis
    ├── controlflow.zig  # Control flow analysis
    ├── source.zig        # Solidity code generation
    └── types.zig         # Type inference

Supported Opcodes

EVM (142 opcodes)

• Arithmetic: ADD, MUL, SUB, DIV, MOD, SDIV, SMOD, ADDMOD, MULMOD, EXP, SIGNEXTEND
• Comparison: LT, GT, SLT, SGT, EQ, ISZERO, AND, OR, XOR, NOT, BYTE, SHL, SHR, SAR
• Environmental: ADDRESS, BALANCE, ORIGIN, CALLER, CALLVALUE, CALLDATALOAD, CALLDATASIZE, CALLDATACOPY, CODESIZE, CODECOPY, GASPRICE, EXTCODESIZE, EXTCODECOPY, RETURNDATASIZE, RETURNDATACOPY, EXTCODEHASH
• Block: COINBASE, TIMESTAMP, NUMBER, DIFFICULTY, GASLIMIT, CHAINID, BASEFEE, BLOBHASH, BLOBBASEFEE
• Stack: PUSH1-PUSH32, POP, DUP1-DUP16, SWAP1-SWAP16
• Memory: MLOAD, MSTORE, MSTORE8, SLOAD, SSTORE
• Control: JUMP, JUMPI, PC, JUMPDEST, RJUMPI
• Logging: LOG0-LOG4
• System: CREATE, CALL, CALLCODE, DELEGATECALL, STATICCALL, CREATE2, REVERT, RETURN, INVALID, SELFDESTRUCT
• And more...

RISC-V (Base)

• LUI, AUIPC, JAL, JALR
• Load: LB, LH, LW, LBU, LHU
• Store: SB, SH, SW
• Branch: BEQ, BNE, BLT, BGE, BLTU, BGEU
• Arithmetic: ADD, SUB, SLT, SLTU, XOR, OR, AND, SLL, SRL, SRA
• Immediate: ADDI, SLTI, SLTIU, XORI, ORI, ANDI, SLLI, SRLI, SRAI

License

GNU General Public License v3 (GPL-3.0) - See LICENSE file