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eosio.evm

Benchmarks

Action CPU Cost
ERC20 Transfer 504µs (TX)
ERC20 Deploy 764µs (TX)
EVM Transfer 325µs (TX)
EVM New Address 553µs (TX)

Achievements

  • Full Javascript SDK for deploying, executing and querying contracts
  • 100% Success on Ethereum Transaction Tests
  • 100% Success on Ethereum RLP Tests
  • REVERT support (challenging on EOS as it requires no use of eosio::check after nonce increment)
  • Istanbul support
  • Full gas cost calculations (not billed to sender)
  • Web3-similar call support (query view functions with no state modifications)
  • Total size less than 200KB (~2MB on-chain)

Usage instructions

Recommended: eos-evm-js guide

Basic usage: cleos guide

Build/Manual Deployment instructions

Requires latest eosio.cdt with latest eosio 2 with EOSVM

Change the token symbol in eosio.evm/include/eosio.evm/constants.hpp to reflect your chain

cmake .
make -j4

No special instructions needed for manual deployment, simply deploy the WASM and ABI from eosio.evm/eosio.evm/ directory

Directory structure

  • eosio.evm: contains all contract code
    • src: all sourcefiles
    • include/eosio.evm: all headerfiles
    • external: external code for ecc, intx (bigint), keccak256 and rlp
  • eos-evm-js: Full JS SDK for deploying both EVM and Ethereum accounts, contracts, fetching state, etc.
  • js-tests: scripts for encoding/decoding transactions for testing
  • tests: full Ethereum/EOS tests
  • truffle: ERC20 and ERC721 contracts

Contract Public Actions

ACTION raw ( const std::vector<int8_t>& tx,
             const std::optional<eosio::checksum160>& sender);
  • tx will take a raw Ethereum transaction RLP hex encoded without the '0x' prefix
  • sender is an optional parameter used when the tx is not signed  
ACTION create ( const eosio::name& account,
                const std::string& data);
  • account is the EOSIO account creating the new Ethereum account
  • data is an arbitrary string used as a salt to create the new Ethereum account  
ACTION withdraw ( const eosio::name& to,
                  const eosio::asset& quantity);
  • account is the EOSIO account associated with an Ethereum account with a balance
  • quantity is an EOSIO asset like "4.0000 SYS" for the amount to withdraw  
[[eosio::on_notify("eosio.token::transfer")]]
void transfer( const eosio::name& from,
                const eosio::name& to,
                const eosio::asset& quantity,
                const std::string& memo );
  • Standard transfer function used to deposit balance into associated Ethereum account. If the depositor does not have an EVM account associated, the transaction will fail to execute.  
ACTION call( const std::vector<int8_t>& tx,
             const std::optional<eosio::checksum160>& sender );
  • Function to mock execute and view result (no state modifications are persisted), similiar to Web3 call()  

Contract Tables

struct Account {
  uint64_t index;
  eosio::checksum160 address;
  eosio::name account;
  eosio::asset balance;
  uint64_t nonce;
  std::vector<uint8_t> code;
}
  • index - auto-incremented counter for accounts, also used as scope index for AccountStates
  • address - Ethereum 160 bit address
  • account - EOSIO account associated with Ethereum account
  • balance - EOSIO asset balance associated with Ethereum account
  • nonce - Current nonce of the account
  • code - Contract code for Ethereum account if present
struct AccountState {
  uint64_t index;
  eosio::checksum256 key;
  bigint::checksum256 value;
}
  • index - auto-incremented counter for account states, only used as primary key
  • key - big-endian encoded key for storage
  • value - big-endian encoded value for storage

EVM Notes

  • We assume that maximum "value" of a transaction is within the limits of a int64_t. Any transaction with a "value" greater than 2^62 - 1 will be considered invalid.
  • Account States are scoped by the index of the account. The index of an account never changes, thus this is guaranteed to be unique.
  • NUMBER opcode returns tapos_block_num, as that is the only EOSIO block number available to contracts
  • The RLP encoding in "create" uses RLP (uint64_t eos_account, uint64_t nonce)
  • No patricia merkle tree is used
  • A value of 1 represents 0.0001 SYS
  • Precompiled contracts are not currently supported, many like ec_mul and ec_add are due to be added to EOSIO soon

Special Mentions

Disclosure

Note that this repository is still in a highly iterative state, if you find any bugs, please open an issue or a pull request.