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