vm

package
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 Go to latest Published: Oct 16, 2020 License: GPL-3.0 Imports: 18 Imported by: 0

Documentation

Overview

Package vm implements the Ethereum Virtual Machine.

The vm package implements one EVM, a byte code VM. The BC (Byte Code) VM loops over a set of bytes and executes them according to the set of rules defined in the Ethereum yellow paper.

Index

Constants

View Source 
const (
	GasQuickStep   uint64 = 2
	GasFastestStep uint64 = 3
	GasFastStep    uint64 = 5
	GasMidStep     uint64 = 8
	GasSlowStep    uint64 = 10
	GasExtStep     uint64 = 20

	GasReturn       uint64 = 0
	GasStop         uint64 = 0
	GasContractByte uint64 = 200
)

Gas costs

Variables

View Source 
var (
	ErrOutOfGas                 = errors.New("out of gas")
	ErrCodeStoreOutOfGas        = errors.New("contract creation code storage out of gas")
	ErrDepth                    = errors.New("max call depth exceeded")
	ErrTraceLimitReached        = errors.New("the number of logs reached the specified limit")
	ErrInsufficientBalance      = errors.New("insufficient balance for transfer")
	ErrContractAddressCollision = errors.New("contract address collision")
	ErrNoCompatibleInterpreter  = errors.New("no compatible interpreter")
)

List execution errors

View Source 
var PrecompiledContractsByzantium = map[common.Address]PrecompiledContract{
	common.BytesToAddress([]byte{1}): &ecrecover{},
	common.BytesToAddress([]byte{2}): &sha256hash{},
	common.BytesToAddress([]byte{3}): &ripemd160hash{},
	common.BytesToAddress([]byte{4}): &dataCopy{},
	common.BytesToAddress([]byte{5}): &bigModExp{},
	common.BytesToAddress([]byte{6}): &bn256Add{},
	common.BytesToAddress([]byte{7}): &bn256ScalarMul{},
	common.BytesToAddress([]byte{8}): &bn256Pairing{},
}

PrecompiledContractsByzantium contains the default set of pre-compiled Ethereum contracts used in the Byzantium release.

View Source 
var PrecompiledContractsHomestead = map[common.Address]PrecompiledContract{
	common.BytesToAddress([]byte{1}): &ecrecover{},
	common.BytesToAddress([]byte{2}): &sha256hash{},
	common.BytesToAddress([]byte{3}): &ripemd160hash{},
	common.BytesToAddress([]byte{4}): &dataCopy{},
}

PrecompiledContractsHomestead contains the default set of pre-compiled Ethereum contracts used in the Frontier and Homestead releases.

Functions

func RunPrecompiledContract 

func RunPrecompiledContract(p PrecompiledContract, input []byte, contract *Contract) (ret []byte, err error)

RunPrecompiledContract runs and evaluates the output of a precompiled contract.

func WriteLogs 

func WriteLogs(writer io.Writer, logs []*types.Log)

WriteLogs writes vm logs in a readable format to the given writer

func WriteTrace 

func WriteTrace(writer io.Writer, logs []StructLog)

WriteTrace writes a formatted trace to the given writer

Types

type AccountRef 

type AccountRef common.Address

AccountRef implements ContractRef.

Account references are used during EVM initialisation and it's primary use is to fetch addresses. Removing this object proves difficult because of the cached jump destinations which are fetched from the parent contract (i.e. the caller), which is a ContractRef.

func (AccountRef) Address 

func (ar AccountRef) Address() common.Address

Address casts AccountRef to a Address

type CallContext 

type CallContext interface {
	// Call another contract
	Call(env *EVM, me ContractRef, addr common.Address, data []byte, gas, value *big.Int) ([]byte, error)
	// Take another's contract code and execute within our own context
	CallCode(env *EVM, me ContractRef, addr common.Address, data []byte, gas, value *big.Int) ([]byte, error)
	// Same as CallCode except sender and value is propagated from parent to child scope
	DelegateCall(env *EVM, me ContractRef, addr common.Address, data []byte, gas *big.Int) ([]byte, error)
	// Create a new contract
	Create(env *EVM, me ContractRef, data []byte, gas, value *big.Int) ([]byte, common.Address, error)
}

CallContext provides a basic interface for the EVM calling conventions. The EVM depends on this context being implemented for doing subcalls and initialising new EVM contracts.

type CanTransferFunc 

type CanTransferFunc func(StateDB, common.Address, *big.Int) bool

CanTransferFunc is the signature of a transfer guard function

type Config 

type Config struct {
	// Debug enabled debugging Interpreter options
	Debug bool
	// Tracer is the op code logger
	Tracer Tracer
	// NoRecursion disabled Interpreter call, callcode,
	// delegate call and create.
	NoRecursion bool
	// Enable recording of SHA3/keccak preimages
	EnablePreimageRecording bool
	// JumpTable contains the EVM instruction table. This
	// may be left uninitialised and will be set to the default
	// table.
	JumpTable [256]operation

	// Type of the EWASM interpreter
	EWASMInterpreter string
	// Type of the EVM interpreter
	EVMInterpreter string
}

Config are the configuration options for the Interpreter

type Context 

type Context struct {
	// CanTransfer returns whether the account contains
	// sufficient ether to transfer the value
	CanTransfer CanTransferFunc
	// Transfer transfers ether from one account to the other
	Transfer TransferFunc
	// 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
}

Context provides the EVM with auxiliary information. Once provided it shouldn't be modified.

type Contract 

type Contract struct {
	// CallerAddress is the result of the caller which initialised this
	// contract. However when the "call method" is delegated this value
	// needs to be initialised to that of the caller's caller.
	CallerAddress common.Address

	Code     []byte
	CodeHash common.Hash
	CodeAddr *common.Address
	Input    []byte

	Gas uint64

	Args []byte

	DelegateCall bool
	// contains filtered or unexported fields
}

Contract represents an ethereum contract in the state database. It contains the contract code, calling arguments. Contract implements ContractRef

func NewContract 

func NewContract(caller ContractRef, object ContractRef, value *big.Int, gas uint64) *Contract

NewContract returns a new contract environment for the execution of EVM.

func (*Contract) Address 

func (c *Contract) Address() common.Address

Address returns the contracts address

func (*Contract) AsDelegate 

func (c *Contract) AsDelegate() *Contract

AsDelegate sets the contract to be a delegate call and returns the current contract (for chaining calls)

func (*Contract) Caller 

func (c *Contract) Caller() common.Address

Caller returns the caller of the contract.

Caller will recursively call caller when the contract is a delegate call, including that of caller's caller.

func (*Contract) GetByte 

func (c *Contract) GetByte(n uint64) byte

GetByte returns the n'th byte in the contract's byte array

func (*Contract) GetOp 

func (c *Contract) GetOp(n uint64) OpCode

GetOp returns the n'th element in the contract's byte array

func (*Contract) SetCallCode 

func (c *Contract) SetCallCode(addr *common.Address, hash common.Hash, code []byte)

SetCallCode sets the code of the contract and address of the backing data object

func (*Contract) SetCode 

func (c *Contract) SetCode(hash common.Hash, code []byte)

SetCode sets the code to the contract

func (*Contract) UseGas 

func (c *Contract) UseGas(gas uint64) (ok bool)

UseGas attempts the use gas and subtracts it and returns true on success

func (*Contract) Value 

func (c *Contract) Value() *big.Int

Value returns the contracts value (sent to it from it's caller)

type ContractRef 

type ContractRef interface {
	Address() common.Address
}

ContractRef is a reference to the contract's backing object

type EVM 

type EVM struct {
	// Context provides auxiliary blockchain related information
	Context
	// StateDB gives access to the underlying state
	StateDB StateDB
	// contains filtered or unexported fields
}

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.

func NewEVM 

func NewEVM(ctx Context, statedb StateDB, chainConfig *params.ChainConfig, vmConfig Config) *EVM

NewEVM returns a new EVM. The returned EVM is not thread safe and should only ever be used *once*.

func (*EVM) Call 

func (evm *EVM) Call(caller ContractRef, addr common.Address, input []byte, gas uint64, value *big.Int) (ret []byte, leftOverGas uint64, err error)

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) CallCode 

func (evm *EVM) CallCode(caller ContractRef, addr common.Address, input []byte, gas uint64, value *big.Int) (ret []byte, leftOverGas uint64, err error)

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) Cancel 

func (evm *EVM) Cancel()

Cancel cancels any running EVM operation. This may be called concurrently and it's safe to be called multiple times.

func (*EVM) ChainConfig 

func (evm *EVM) ChainConfig() *params.ChainConfig

ChainConfig returns the environment's chain configuration

func (*EVM) Create 

func (evm *EVM) Create(caller ContractRef, code []byte, gas uint64, value *big.Int) (ret []byte, contractAddr common.Address, leftOverGas uint64, err error)

Create creates a new contract using code as deployment code.

func (*EVM) Create2 

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)

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) Create3 

func (evm *EVM) Create3(contract common.Address, caller ContractRef, code []byte, gas uint64, value *big.Int) (ret []byte, contractAddr common.Address, leftOverGas uint64, err error)

Create creates a new contract using code as deployment code.

func (*EVM) DelegateCall 

func (evm *EVM) DelegateCall(caller ContractRef, addr common.Address, input []byte, gas uint64) (ret []byte, leftOverGas uint64, err error)

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) Interpreter 

func (evm *EVM) Interpreter() Interpreter

Interpreter returns the current interpreter

func (*EVM) StaticCall 

func (evm *EVM) StaticCall(caller ContractRef, addr common.Address, input []byte, gas uint64) (ret []byte, leftOverGas uint64, err error)

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.

type EVMInterpreter 

type EVMInterpreter struct {
	// contains filtered or unexported fields
}

EVMInterpreter represents an EVM interpreter

func NewEVMInterpreter 

func NewEVMInterpreter(evm *EVM, cfg Config) *EVMInterpreter

NewEVMInterpreter returns a new instance of the Interpreter.

func (*EVMInterpreter) CanRun 

func (in *EVMInterpreter) CanRun(code []byte) bool

CanRun tells if the contract, passed as an argument, can be run by the current interpreter.

func (*EVMInterpreter) Run 

func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (ret []byte, err error)

Run loops and evaluates the contract's code with the given input data and returns the return byte-slice and an error if one occurred.

It's important to note that any errors returned by the interpreter should be considered a revert-and-consume-all-gas operation except for errExecutionReverted which means revert-and-keep-gas-left.

type GetHashFunc 

type GetHashFunc func(uint64) common.Hash

GetHashFunc returns the nth block hash in the blockchain and is used by the BLOCKHASH EVM op code.

type Interpreter 

type Interpreter interface {
	// Run loops and evaluates the contract's code with the given input data and returns
	// the return byte-slice and an error if one occurred.
	Run(contract *Contract, input []byte, static bool) ([]byte, error)
	// CanRun tells if the contract, passed as an argument, can be
	// run by the current interpreter. This is meant so that the
	// caller can do something like:
	//
	// “`golang
	// for _, interpreter := range interpreters {
	//   if interpreter.CanRun(contract.code) {
	//     interpreter.Run(contract.code, input)
	//   }
	// }
	// “`
	CanRun([]byte) bool
}

Interpreter is used to run Ethereum based contracts and will utilise the passed environment to query external sources for state information. The Interpreter will run the byte code VM based on the passed configuration.

type LogConfig 

type LogConfig struct {
	DisableMemory  bool // disable memory capture
	DisableStack   bool // disable stack capture
	DisableStorage bool // disable storage capture
	Debug          bool // print output during capture end
	Limit          int  // maximum length of output, but zero means unlimited
}

LogConfig are the configuration options for structured logger the EVM

type Memory 

type Memory struct {
	// contains filtered or unexported fields
}

Memory implements a simple memory model for the ethereum virtual machine.

func NewMemory 

func NewMemory() *Memory

NewMemory returns a new memory memory model.

func (*Memory) Data 

func (m *Memory) Data() []byte

Data returns the backing slice

func (*Memory) Get 

func (m *Memory) Get(offset, size int64) (cpy []byte)

Get returns offset + size as a new slice

func (*Memory) GetPtr 

func (m *Memory) GetPtr(offset, size int64) []byte

GetPtr returns the offset + size

func (*Memory) Len 

func (m *Memory) Len() int

Len returns the length of the backing slice

func (*Memory) Print 

func (m *Memory) Print()

Print dumps the content of the memory.

func (*Memory) Resize 

func (m *Memory) Resize(size uint64)

Resize resizes the memory to size

func (*Memory) Set 

func (m *Memory) Set(offset, size uint64, value []byte)

Set sets offset + size to value

func (*Memory) Set32 

func (m *Memory) Set32(offset uint64, val *big.Int)

Set32 sets the 32 bytes starting at offset to the value of val, left-padded with zeroes to 32 bytes.

type OpCode 

type OpCode byte

OpCode is an EVM opcode 

const (
	STOP OpCode = iota
	ADD
	MUL
	SUB
	DIV
	SDIV
	MOD
	SMOD
	ADDMOD
	MULMOD
	EXP
	SIGNEXTEND
)

0x0 range - arithmetic ops. 

const (
	LT OpCode = iota + 0x10
	GT
	SLT
	SGT
	EQ
	ISZERO
	AND
	OR
	XOR
	NOT
	BYTE
	SHL
	SHR
	SAR

	SHA3 = 0x20
)

0x10 range - comparison ops. 

const (
	ADDRESS OpCode = 0x30 + iota
	BALANCE
	ORIGIN
	CALLER
	CALLVALUE
	CALLDATALOAD
	CALLDATASIZE
	CALLDATACOPY
	CODESIZE
	CODECOPY
	GASPRICE
	EXTCODESIZE
	EXTCODECOPY
	RETURNDATASIZE
	RETURNDATACOPY
	EXTCODEHASH
)

0x30 range - closure state. 

const (
	BLOCKHASH OpCode = 0x40 + iota
	COINBASE
	TIMESTAMP
	NUMBER
	DIFFICULTY
	GASLIMIT
)

0x40 range - block operations. 

const (
	POP OpCode = 0x50 + iota
	MLOAD
	MSTORE
	MSTORE8
	SLOAD
	SSTORE
	JUMP
	JUMPI
	PC
	MSIZE
	GAS
	JUMPDEST
)

0x50 range - 'storage' and execution. 

const (
	PUSH1 OpCode = 0x60 + iota
	PUSH2
	PUSH3
	PUSH4
	PUSH5
	PUSH6
	PUSH7
	PUSH8
	PUSH9
	PUSH10
	PUSH11
	PUSH12
	PUSH13
	PUSH14
	PUSH15
	PUSH16
	PUSH17
	PUSH18
	PUSH19
	PUSH20
	PUSH21
	PUSH22
	PUSH23
	PUSH24
	PUSH25
	PUSH26
	PUSH27
	PUSH28
	PUSH29
	PUSH30
	PUSH31
	PUSH32
	DUP1
	DUP2
	DUP3
	DUP4
	DUP5
	DUP6
	DUP7
	DUP8
	DUP9
	DUP10
	DUP11
	DUP12
	DUP13
	DUP14
	DUP15
	DUP16
	SWAP1
	SWAP2
	SWAP3
	SWAP4
	SWAP5
	SWAP6
	SWAP7
	SWAP8
	SWAP9
	SWAP10
	SWAP11
	SWAP12
	SWAP13
	SWAP14
	SWAP15
	SWAP16
)

0x60 range. 

const (
	LOG0 OpCode = 0xa0 + iota
	LOG1
	LOG2
	LOG3
	LOG4
)

0xa0 range - logging ops. 

const (
	PUSH OpCode = 0xb0 + iota
	DUP
	SWAP
)

unofficial opcodes used for parsing. 

const (
	CREATE OpCode = 0xf0 + iota
	CALL
	CALLCODE
	RETURN
	DELEGATECALL
	CREATE2
	STATICCALL = 0xfa

	REVERT       = 0xfd
	SELFDESTRUCT = 0xff
)

0xf0 range - closures.

func StringToOp 

func StringToOp(str string) OpCode

StringToOp finds the opcode whose name is stored in `str`.

func (OpCode) IsPush 

func (op OpCode) IsPush() bool

IsPush specifies if an opcode is a PUSH opcode.

func (OpCode) IsStaticJump 

func (op OpCode) IsStaticJump() bool

IsStaticJump specifies if an opcode is JUMP.

func (OpCode) String 

func (op OpCode) String() string

type PrecompiledContract 

type PrecompiledContract interface {
	RequiredGas(input []byte) uint64  // RequiredPrice calculates the contract gas use
	Run(input []byte) ([]byte, error) // Run runs the precompiled contract
}

PrecompiledContract is the basic interface for native Go contracts. The implementation requires a deterministic gas count based on the input size of the Run method of the contract.

type Stack 

type Stack struct {
	// contains filtered or unexported fields
}

Stack is an object for basic stack operations. Items popped to the stack are expected to be changed and modified. stack does not take care of adding newly initialised objects.

func (*Stack) Back 

func (st *Stack) Back(n int) *big.Int

Back returns the n'th item in stack

func (*Stack) Data 

func (st *Stack) Data() []*big.Int

Data returns the underlying big.Int array.

func (*Stack) Print 

func (st *Stack) Print()

Print dumps the content of the stack

type StateDB 

type StateDB interface {
	CreateAccount(common.Address)

	SubBalance(common.Address, *big.Int)
	AddBalance(common.Address, *big.Int)
	GetBalance(common.Address) *big.Int

	GetNonce(common.Address) uint64
	SetNonce(common.Address, uint64)

	GetCodeHash(common.Address) common.Hash
	GetCode(common.Address) []byte
	SetCode(common.Address, []byte)
	GetCodeSize(common.Address) int

	AddRefund(uint64)
	SubRefund(uint64)
	GetRefund() uint64

	GetCommittedState(common.Address, common.Hash) common.Hash
	GetState(common.Address, common.Hash) common.Hash
	SetState(common.Address, common.Hash, common.Hash)

	Suicide(common.Address) bool
	HasSuicided(common.Address) bool

	// Exist reports whether the given account exists in state.
	// Notably this should also return true for suicided accounts.
	Exist(common.Address) bool
	// Empty returns whether the given account is empty. Empty
	// is defined according to EIP161 (balance = nonce = code = 0).
	Empty(common.Address) bool

	RevertToSnapshot(int)
	Snapshot() int

	AddLog(*types.Log)
	AddPreimage(common.Hash, []byte)

	ForEachStorage(common.Address, func(common.Hash, common.Hash) bool)
}

StateDB is an EVM database for full state querying.

type Storage 

type Storage map[common.Hash]common.Hash

Storage represents a contract's storage.

func (Storage) Copy 

func (s Storage) Copy() Storage

Copy duplicates the current storage.

type StructLog 

type StructLog struct {
	Pc         uint64                      `json:"pc"`
	Op         OpCode                      `json:"op"`
	Gas        uint64                      `json:"gas"`
	GasCost    uint64                      `json:"gasCost"`
	Memory     []byte                      `json:"memory"`
	MemorySize int                         `json:"memSize"`
	Stack      []*big.Int                  `json:"stack"`
	Storage    map[common.Hash]common.Hash `json:"-"`
	Depth      int                         `json:"depth"`
	Err        error                       `json:"-"`
}

StructLog is emitted to the EVM each cycle and lists information about the current internal state prior to the execution of the statement.

func (*StructLog) ErrorString 

func (s *StructLog) ErrorString() string

ErrorString formats the log's error as a string.

func (StructLog) MarshalJSON 

func (s StructLog) MarshalJSON() ([]byte, error)

func (*StructLog) OpName 

func (s *StructLog) OpName() string

OpName formats the operand name in a human-readable format.

func (*StructLog) UnmarshalJSON 

func (s *StructLog) UnmarshalJSON(input []byte) error

type StructLogger 

type StructLogger struct {
	// contains filtered or unexported fields
}

StructLogger is an EVM state logger and implements Tracer.

StructLogger can capture state based on the given Log configuration and also keeps a track record of modified storage which is used in reporting snapshots of the contract their storage.

func NewStructLogger 

func NewStructLogger(cfg *LogConfig) *StructLogger

NewStructLogger returns a new logger

func (*StructLogger) CaptureEnd 

func (l *StructLogger) CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error) error

CaptureEnd is called after the call finishes to finalize the tracing.

func (*StructLogger) CaptureFault 

func (l *StructLogger) CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, contract *Contract, depth int, err error) error

CaptureFault implements the Tracer interface to trace an execution fault while running an opcode.

func (*StructLogger) CaptureStart 

func (l *StructLogger) CaptureStart(from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) error

CaptureStart implements the Tracer interface to initialize the tracing operation.

func (*StructLogger) CaptureState 

func (l *StructLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, contract *Contract, depth int, err error) error

CaptureState logs a new structured log message and pushes it out to the environment

CaptureState also tracks SSTORE ops to track dirty values.

func (*StructLogger) Error 

func (l *StructLogger) Error() error

Error returns the VM error captured by the trace.

func (*StructLogger) Output 

func (l *StructLogger) Output() []byte

Output returns the VM return value captured by the trace.

func (*StructLogger) StructLogs 

func (l *StructLogger) StructLogs() []StructLog

StructLogs returns the captured log entries.

type Tracer 

type Tracer interface {
	CaptureStart(from common.Address, to common.Address, call bool, input []byte, gas uint64, value *big.Int) error
	CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, contract *Contract, depth int, err error) error
	CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, contract *Contract, depth int, err error) error
	CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error) error
}

Tracer is used to collect execution traces from an EVM transaction execution. CaptureState is called for each step of the VM with the current VM state. Note that reference types are actual VM data structures; make copies if you need to retain them beyond the current call.

type TransferFunc 

type TransferFunc func(StateDB, common.Address, common.Address, *big.Int)

TransferFunc is the signature of a transfer function

Source Files

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Directories

Path Synopsis
Package runtime provides a basic execution model for executing EVM code.
 Package runtime provides a basic execution model for executing EVM code.

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