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+// Copyright 2014 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package vm
+
+import (
+ "math/big"
+ "sync/atomic"
+ "time"
+
+ "github.com/ava-labs/coreth/params"
+ "github.com/ava-labs/go-ethereum/common"
+ "github.com/ava-labs/go-ethereum/crypto"
+)
+
+// emptyCodeHash is used by create to ensure deployment is disallowed to already
+// deployed contract addresses (relevant after the account abstraction).
+var emptyCodeHash = crypto.Keccak256Hash(nil)
+
+type (
+ // CanTransferFunc is the signature of a transfer guard function
+ CanTransferFunc func(StateDB, common.Address, *big.Int) bool
+ CanTransferMCFunc func(StateDB, common.Address, common.Address, *common.Hash, *big.Int) int
+ // TransferFunc is the signature of a transfer function
+ TransferFunc func(StateDB, common.Address, common.Address, *big.Int)
+ TransferMCFunc func(StateDB, common.Address, common.Address, *common.Hash, *big.Int)
+ // GetHashFunc returns the n'th block hash in the blockchain
+ // and is used by the BLOCKHASH EVM op code.
+ GetHashFunc func(uint64) common.Hash
+)
+
+// run runs the given contract and takes care of running precompiles with a fallback to the byte code interpreter.
+func run(evm *EVM, contract *Contract, input []byte, readOnly bool) ([]byte, error) {
+ if contract.CodeAddr != nil {
+ precompiles := PrecompiledContractsHomestead
+ if evm.chainRules.IsByzantium {
+ precompiles = PrecompiledContractsByzantium
+ }
+ if evm.chainRules.IsIstanbul {
+ precompiles = PrecompiledContractsIstanbul
+ }
+ if p := precompiles[*contract.CodeAddr]; p != nil {
+ return RunPrecompiledContract(p, input, contract)
+ }
+ }
+ for _, interpreter := range evm.interpreters {
+ if interpreter.CanRun(contract.Code) {
+ if evm.interpreter != interpreter {
+ // Ensure that the interpreter pointer is set back
+ // to its current value upon return.
+ defer func(i Interpreter) {
+ evm.interpreter = i
+ }(evm.interpreter)
+ evm.interpreter = interpreter
+ }
+ return interpreter.Run(contract, input, readOnly)
+ }
+ }
+ return nil, ErrNoCompatibleInterpreter
+}
+
+// Context provides the EVM with auxiliary information. Once provided
+// it shouldn't be modified.
+type Context struct {
+ // CanTransfer returns whether the account contains
+ // sufficient ether to transfer the value
+ CanTransfer CanTransferFunc
+ CanTransferMC CanTransferMCFunc
+ // Transfer transfers ether from one account to the other
+ Transfer TransferFunc
+ TransferMultiCoin TransferMCFunc
+ // GetHash returns the hash corresponding to n
+ GetHash GetHashFunc
+
+ // Message information
+ Origin common.Address // Provides information for ORIGIN
+ GasPrice *big.Int // Provides information for GASPRICE
+
+ // Block information
+ Coinbase common.Address // Provides information for COINBASE
+ GasLimit uint64 // Provides information for GASLIMIT
+ BlockNumber *big.Int // Provides information for NUMBER
+ Time *big.Int // Provides information for TIME
+ Difficulty *big.Int // Provides information for DIFFICULTY
+}
+
+// EVM is the Ethereum Virtual Machine base object and provides
+// the necessary tools to run a contract on the given state with
+// the provided context. It should be noted that any error
+// generated through any of the calls should be considered a
+// revert-state-and-consume-all-gas operation, no checks on
+// specific errors should ever be performed. The interpreter makes
+// sure that any errors generated are to be considered faulty code.
+//
+// The EVM should never be reused and is not thread safe.
+type EVM struct {
+ // Context provides auxiliary blockchain related information
+ Context
+ // StateDB gives access to the underlying state
+ StateDB StateDB
+ // Depth is the current call stack
+ depth int
+
+ // chainConfig contains information about the current chain
+ chainConfig *params.ChainConfig
+ // chain rules contains the chain rules for the current epoch
+ chainRules params.Rules
+ // virtual machine configuration options used to initialise the
+ // evm.
+ vmConfig Config
+ // global (to this context) ethereum virtual machine
+ // used throughout the execution of the tx.
+ interpreters []Interpreter
+ interpreter Interpreter
+ // abort is used to abort the EVM calling operations
+ // NOTE: must be set atomically
+ abort int32
+ // callGasTemp holds the gas available for the current call. This is needed because the
+ // available gas is calculated in gasCall* according to the 63/64 rule and later
+ // applied in opCall*.
+ callGasTemp uint64
+}
+
+// NewEVM returns a new EVM. The returned EVM is not thread safe and should
+// only ever be used *once*.
+func NewEVM(ctx Context, statedb StateDB, chainConfig *params.ChainConfig, vmConfig Config) *EVM {
+ evm := &EVM{
+ Context: ctx,
+ StateDB: statedb,
+ vmConfig: vmConfig,
+ chainConfig: chainConfig,
+ chainRules: chainConfig.Rules(ctx.BlockNumber),
+ interpreters: make([]Interpreter, 0, 1),
+ }
+
+ if chainConfig.IsEWASM(ctx.BlockNumber) {
+ // to be implemented by EVM-C and Wagon PRs.
+ // if vmConfig.EWASMInterpreter != "" {
+ // extIntOpts := strings.Split(vmConfig.EWASMInterpreter, ":")
+ // path := extIntOpts[0]
+ // options := []string{}
+ // if len(extIntOpts) > 1 {
+ // options = extIntOpts[1..]
+ // }
+ // evm.interpreters = append(evm.interpreters, NewEVMVCInterpreter(evm, vmConfig, options))
+ // } else {
+ // evm.interpreters = append(evm.interpreters, NewEWASMInterpreter(evm, vmConfig))
+ // }
+ panic("No supported ewasm interpreter yet.")
+ }
+
+ // vmConfig.EVMInterpreter will be used by EVM-C, it won't be checked here
+ // as we always want to have the built-in EVM as the failover option.
+ evm.interpreters = append(evm.interpreters, NewEVMInterpreter(evm, vmConfig))
+ evm.interpreter = evm.interpreters[0]
+
+ return evm
+}
+
+// Cancel cancels any running EVM operation. This may be called concurrently and
+// it's safe to be called multiple times.
+func (evm *EVM) Cancel() {
+ atomic.StoreInt32(&evm.abort, 1)
+}
+
+// Cancelled returns true if Cancel has been called
+func (evm *EVM) Cancelled() bool {
+ return atomic.LoadInt32(&evm.abort) == 1
+}
+
+// Interpreter returns the current interpreter
+func (evm *EVM) Interpreter() Interpreter {
+ return evm.interpreter
+}
+
+// Call executes the contract associated with the addr with the given input as
+// parameters. It also handles any necessary value transfer required and takes
+// the necessary steps to create accounts and reverses the state in case of an
+// execution error or failed value transfer.
+func (evm *EVM) Call(caller ContractRef, addr common.Address, input []byte, gas uint64, value *big.Int) (ret []byte, leftOverGas uint64, err error) {
+ if evm.vmConfig.NoRecursion && evm.depth > 0 {
+ return nil, gas, nil
+ }
+
+ // Fail if we're trying to execute above the call depth limit
+ if evm.depth > int(params.CallCreateDepth) {
+ return nil, gas, ErrDepth
+ }
+ // Fail if we're trying to transfer more than the available balance
+ if !evm.Context.CanTransfer(evm.StateDB, caller.Address(), value) {
+ return nil, gas, ErrInsufficientBalance
+ }
+
+ var (
+ to = AccountRef(addr)
+ snapshot = evm.StateDB.Snapshot()
+ )
+ if !evm.StateDB.Exist(addr) {
+ precompiles := PrecompiledContractsHomestead
+ if evm.chainRules.IsByzantium {
+ precompiles = PrecompiledContractsByzantium
+ }
+ if evm.chainRules.IsIstanbul {
+ precompiles = PrecompiledContractsIstanbul
+ }
+ if precompiles[addr] == nil && evm.chainRules.IsEIP158 && value.Sign() == 0 {
+ // Calling a non existing account, don't do anything, but ping the tracer
+ if evm.vmConfig.Debug && evm.depth == 0 {
+ evm.vmConfig.Tracer.CaptureStart(caller.Address(), addr, false, input, gas, value)
+ evm.vmConfig.Tracer.CaptureEnd(ret, 0, 0, nil)
+ }
+ return nil, gas, nil
+ }
+ evm.StateDB.CreateAccount(addr)
+ }
+ evm.Transfer(evm.StateDB, caller.Address(), to.Address(), value)
+ // Initialise a new contract and set the code that is to be used by the EVM.
+ // The contract is a scoped environment for this execution context only.
+ contract := NewContract(caller, to, value, gas)
+ contract.SetCallCode(&addr, evm.StateDB.GetCodeHash(addr), evm.StateDB.GetCode(addr))
+
+ // Even if the account has no code, we need to continue because it might be a precompile
+ start := time.Now()
+
+ // Capture the tracer start/end events in debug mode
+ if evm.vmConfig.Debug && evm.depth == 0 {
+ evm.vmConfig.Tracer.CaptureStart(caller.Address(), addr, false, input, gas, value)
+
+ defer func() { // Lazy evaluation of the parameters
+ evm.vmConfig.Tracer.CaptureEnd(ret, gas-contract.Gas, time.Since(start), err)
+ }()
+ }
+ ret, err = run(evm, contract, input, false)
+
+ // When an error was returned by the EVM or when setting the creation code
+ // above we revert to the snapshot and consume any gas remaining. Additionally
+ // when we're in homestead this also counts for code storage gas errors.
+ if err != nil {
+ evm.StateDB.RevertToSnapshot(snapshot)
+ if err != errExecutionReverted {
+ contract.UseGas(contract.Gas)
+ }
+ }
+ return ret, contract.Gas, err
+}
+
+// This allows the user transfer balance of a specified coinId in addition to a normal Call().
+func (evm *EVM) CallExpert(caller ContractRef, addr common.Address, input []byte, gas uint64, value *big.Int, coinID *common.Hash, value2 *big.Int) (ret []byte, leftOverGas uint64, err error) {
+ if evm.vmConfig.NoRecursion && evm.depth > 0 {
+ return nil, gas, nil
+ }
+
+ // Fail if we're trying to execute above the call depth limit
+ if evm.depth > int(params.CallCreateDepth) {
+ return nil, gas, ErrDepth
+ }
+ // Fail if we're trying to transfer more than the available balance
+ if !evm.Context.CanTransfer(evm.StateDB, caller.Address(), value) {
+ return nil, gas, ErrInsufficientBalance
+ }
+
+ var to = AccountRef(addr)
+ mcerr := evm.Context.CanTransferMC(evm.StateDB, caller.Address(), to.Address(), coinID, value2)
+ if mcerr == 1 {
+ return nil, gas, ErrInsufficientBalance
+ } else if mcerr != 0 {
+ return nil, gas, ErrIncompatibleAccount
+ }
+
+ var snapshot = evm.StateDB.Snapshot()
+
+ if !evm.StateDB.Exist(addr) {
+ precompiles := PrecompiledContractsHomestead
+ if evm.chainRules.IsByzantium {
+ precompiles = PrecompiledContractsByzantium
+ }
+ if evm.chainRules.IsIstanbul {
+ precompiles = PrecompiledContractsIstanbul
+ }
+ if precompiles[addr] == nil && evm.chainRules.IsEIP158 && value.Sign() == 0 {
+ // Calling a non existing account, don't do anything, but ping the tracer
+ if evm.vmConfig.Debug && evm.depth == 0 {
+ evm.vmConfig.Tracer.CaptureStart(caller.Address(), addr, false, input, gas, value)
+ evm.vmConfig.Tracer.CaptureEnd(ret, 0, 0, nil)
+ }
+ return nil, gas, nil
+ }
+ evm.StateDB.CreateAccount(addr)
+ }
+ evm.Transfer(evm.StateDB, caller.Address(), to.Address(), value)
+ evm.TransferMultiCoin(evm.StateDB, caller.Address(), to.Address(), coinID, value2)
+ // Initialise a new contract and set the code that is to be used by the EVM.
+ // The contract is a scoped environment for this execution context only.
+ contract := NewContract(caller, to, value, gas)
+ contract.SetCallCode(&addr, evm.StateDB.GetCodeHash(addr), evm.StateDB.GetCode(addr))
+
+ // Even if the account has no code, we need to continue because it might be a precompile
+ start := time.Now()
+
+ // Capture the tracer start/end events in debug mode
+ if evm.vmConfig.Debug && evm.depth == 0 {
+ evm.vmConfig.Tracer.CaptureStart(caller.Address(), addr, false, input, gas, value)
+
+ defer func() { // Lazy evaluation of the parameters
+ evm.vmConfig.Tracer.CaptureEnd(ret, gas-contract.Gas, time.Since(start), err)
+ }()
+ }
+ ret, err = run(evm, contract, input, false)
+
+ // When an error was returned by the EVM or when setting the creation code
+ // above we revert to the snapshot and consume any gas remaining. Additionally
+ // when we're in homestead this also counts for code storage gas errors.
+ if err != nil {
+ evm.StateDB.RevertToSnapshot(snapshot)
+ if err != errExecutionReverted {
+ contract.UseGas(contract.Gas)
+ }
+ }
+ return ret, contract.Gas, err
+}
+
+// CallCode executes the contract associated with the addr with the given input
+// as parameters. It also handles any necessary value transfer required and takes
+// the necessary steps to create accounts and reverses the state in case of an
+// execution error or failed value transfer.
+//
+// CallCode differs from Call in the sense that it executes the given address'
+// code with the caller as context.
+func (evm *EVM) CallCode(caller ContractRef, addr common.Address, input []byte, gas uint64, value *big.Int) (ret []byte, leftOverGas uint64, err error) {
+ if evm.vmConfig.NoRecursion && evm.depth > 0 {
+ return nil, gas, nil
+ }
+
+ // Fail if we're trying to execute above the call depth limit
+ if evm.depth > int(params.CallCreateDepth) {
+ return nil, gas, ErrDepth
+ }
+ // Fail if we're trying to transfer more than the available balance
+ if !evm.CanTransfer(evm.StateDB, caller.Address(), value) {
+ return nil, gas, ErrInsufficientBalance
+ }
+
+ var (
+ snapshot = evm.StateDB.Snapshot()
+ to = AccountRef(caller.Address())
+ )
+ // Initialise a new contract and set the code that is to be used by the EVM.
+ // The contract is a scoped environment for this execution context only.
+ contract := NewContract(caller, to, value, gas)
+ contract.SetCallCode(&addr, evm.StateDB.GetCodeHash(addr), evm.StateDB.GetCode(addr))
+
+ ret, err = run(evm, contract, input, false)
+ if err != nil {
+ evm.StateDB.RevertToSnapshot(snapshot)
+ if err != errExecutionReverted {
+ contract.UseGas(contract.Gas)
+ }
+ }
+ return ret, contract.Gas, err
+}
+
+// DelegateCall executes the contract associated with the addr with the given input
+// as parameters. It reverses the state in case of an execution error.
+//
+// DelegateCall differs from CallCode in the sense that it executes the given address'
+// code with the caller as context and the caller is set to the caller of the caller.
+func (evm *EVM) DelegateCall(caller ContractRef, addr common.Address, input []byte, gas uint64) (ret []byte, leftOverGas uint64, err error) {
+ if evm.vmConfig.NoRecursion && evm.depth > 0 {
+ return nil, gas, nil
+ }
+ // Fail if we're trying to execute above the call depth limit
+ if evm.depth > int(params.CallCreateDepth) {
+ return nil, gas, ErrDepth
+ }
+
+ var (
+ snapshot = evm.StateDB.Snapshot()
+ to = AccountRef(caller.Address())
+ )
+
+ // Initialise a new contract and make initialise the delegate values
+ contract := NewContract(caller, to, nil, gas).AsDelegate()
+ contract.SetCallCode(&addr, evm.StateDB.GetCodeHash(addr), evm.StateDB.GetCode(addr))
+
+ ret, err = run(evm, contract, input, false)
+ if err != nil {
+ evm.StateDB.RevertToSnapshot(snapshot)
+ if err != errExecutionReverted {
+ contract.UseGas(contract.Gas)
+ }
+ }
+ return ret, contract.Gas, err
+}
+
+// StaticCall executes the contract associated with the addr with the given input
+// as parameters while disallowing any modifications to the state during the call.
+// Opcodes that attempt to perform such modifications will result in exceptions
+// instead of performing the modifications.
+func (evm *EVM) StaticCall(caller ContractRef, addr common.Address, input []byte, gas uint64) (ret []byte, leftOverGas uint64, err error) {
+ if evm.vmConfig.NoRecursion && evm.depth > 0 {
+ return nil, gas, nil
+ }
+ // Fail if we're trying to execute above the call depth limit
+ if evm.depth > int(params.CallCreateDepth) {
+ return nil, gas, ErrDepth
+ }
+
+ var (
+ to = AccountRef(addr)
+ snapshot = evm.StateDB.Snapshot()
+ )
+ // Initialise a new contract and set the code that is to be used by the EVM.
+ // The contract is a scoped environment for this execution context only.
+ contract := NewContract(caller, to, new(big.Int), gas)
+ contract.SetCallCode(&addr, evm.StateDB.GetCodeHash(addr), evm.StateDB.GetCode(addr))
+
+ // We do an AddBalance of zero here, just in order to trigger a touch.
+ // This doesn't matter on Mainnet, where all empties are gone at the time of Byzantium,
+ // but is the correct thing to do and matters on other networks, in tests, and potential
+ // future scenarios
+ evm.StateDB.AddBalance(addr, bigZero)
+
+ // When an error was returned by the EVM or when setting the creation code
+ // above we revert to the snapshot and consume any gas remaining. Additionally
+ // when we're in Homestead this also counts for code storage gas errors.
+ ret, err = run(evm, contract, input, true)
+ if err != nil {
+ evm.StateDB.RevertToSnapshot(snapshot)
+ if err != errExecutionReverted {
+ contract.UseGas(contract.Gas)
+ }
+ }
+ return ret, contract.Gas, err
+}
+
+type codeAndHash struct {
+ code []byte
+ hash common.Hash
+}
+
+func (c *codeAndHash) Hash() common.Hash {
+ if c.hash == (common.Hash{}) {
+ c.hash = crypto.Keccak256Hash(c.code)
+ }
+ return c.hash
+}
+
+// create creates a new contract using code as deployment code.
+func (evm *EVM) create(caller ContractRef, codeAndHash *codeAndHash, gas uint64, value *big.Int, address common.Address) ([]byte, common.Address, uint64, error) {
+ // Depth check execution. Fail if we're trying to execute above the
+ // limit.
+ if evm.depth > int(params.CallCreateDepth) {
+ return nil, common.Address{}, gas, ErrDepth
+ }
+ if !evm.CanTransfer(evm.StateDB, caller.Address(), value) {
+ return nil, common.Address{}, gas, ErrInsufficientBalance
+ }
+ nonce := evm.StateDB.GetNonce(caller.Address())
+ evm.StateDB.SetNonce(caller.Address(), nonce+1)
+
+ // Ensure there's no existing contract already at the designated address
+ contractHash := evm.StateDB.GetCodeHash(address)
+ if evm.StateDB.GetNonce(address) != 0 || (contractHash != (common.Hash{}) && contractHash != emptyCodeHash) {
+ return nil, common.Address{}, 0, ErrContractAddressCollision
+ }
+ // Create a new account on the state
+ snapshot := evm.StateDB.Snapshot()
+ evm.StateDB.CreateAccount(address)
+ if evm.chainRules.IsEIP158 {
+ evm.StateDB.SetNonce(address, 1)
+ }
+ evm.Transfer(evm.StateDB, caller.Address(), address, value)
+
+ // Initialise a new contract and set the code that is to be used by the EVM.
+ // The contract is a scoped environment for this execution context only.
+ contract := NewContract(caller, AccountRef(address), value, gas)
+ contract.SetCodeOptionalHash(&address, codeAndHash)
+
+ if evm.vmConfig.NoRecursion && evm.depth > 0 {
+ return nil, address, gas, nil
+ }
+
+ if evm.vmConfig.Debug && evm.depth == 0 {
+ evm.vmConfig.Tracer.CaptureStart(caller.Address(), address, true, codeAndHash.code, gas, value)
+ }
+ start := time.Now()
+
+ ret, err := run(evm, contract, nil, false)
+
+ // check whether the max code size has been exceeded
+ maxCodeSizeExceeded := evm.chainRules.IsEIP158 && len(ret) > params.MaxCodeSize
+ // if the contract creation ran successfully and no errors were returned
+ // calculate the gas required to store the code. If the code could not
+ // be stored due to not enough gas set an error and let it be handled
+ // by the error checking condition below.
+ if err == nil && !maxCodeSizeExceeded {
+ createDataGas := uint64(len(ret)) * params.CreateDataGas
+ if contract.UseGas(createDataGas) {
+ evm.StateDB.SetCode(address, ret)
+ } else {
+ err = ErrCodeStoreOutOfGas
+ }
+ }
+
+ // When an error was returned by the EVM or when setting the creation code
+ // above we revert to the snapshot and consume any gas remaining. Additionally
+ // when we're in homestead this also counts for code storage gas errors.
+ if maxCodeSizeExceeded || (err != nil && (evm.chainRules.IsHomestead || err != ErrCodeStoreOutOfGas)) {
+ evm.StateDB.RevertToSnapshot(snapshot)
+ if err != errExecutionReverted {
+ contract.UseGas(contract.Gas)
+ }
+ }
+ // Assign err if contract code size exceeds the max while the err is still empty.
+ if maxCodeSizeExceeded && err == nil {
+ err = errMaxCodeSizeExceeded
+ }
+ if evm.vmConfig.Debug && evm.depth == 0 {
+ evm.vmConfig.Tracer.CaptureEnd(ret, gas-contract.Gas, time.Since(start), err)
+ }
+ return ret, address, contract.Gas, err
+
+}
+
+// Create creates a new contract using code as deployment code.
+func (evm *EVM) Create(caller ContractRef, code []byte, gas uint64, value *big.Int) (ret []byte, contractAddr common.Address, leftOverGas uint64, err error) {
+ contractAddr = crypto.CreateAddress(caller.Address(), evm.StateDB.GetNonce(caller.Address()))
+ return evm.create(caller, &codeAndHash{code: code}, gas, value, contractAddr)
+}
+
+// Create2 creates a new contract using code as deployment code.
+//
+// The different between Create2 with Create is Create2 uses sha3(0xff ++ msg.sender ++ salt ++ sha3(init_code))[12:]
+// instead of the usual sender-and-nonce-hash as the address where the contract is initialized at.
+func (evm *EVM) Create2(caller ContractRef, code []byte, gas uint64, endowment *big.Int, salt *big.Int) (ret []byte, contractAddr common.Address, leftOverGas uint64, err error) {
+ codeAndHash := &codeAndHash{code: code}
+ contractAddr = crypto.CreateAddress2(caller.Address(), common.BigToHash(salt), codeAndHash.Hash().Bytes())
+ return evm.create(caller, codeAndHash, gas, endowment, contractAddr)
+}
+
+// ChainConfig returns the environment's chain configuration
+func (evm *EVM) ChainConfig() *params.ChainConfig { return evm.chainConfig }
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