vm

package
v1.3.1 Latest Latest
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 Go to latest Published: Oct 31, 2015 License: GPL-3.0 Imports: 16 Imported by: 8

Documentation

Overview

Package vm implements the Ethereum Virtual Machine.

The vm package implements two EVMs, a byte code VM and a JIT 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. When the BC VM is invoked it invokes the JIT VM in a seperate goroutine and compiles the byte code in JIT instructions.

The JIT VM, when invoked, loops around a set of pre-defined instructions until it either runs of gas, causes an internal error, returns or stops.

The JIT optimiser attempts to pre-compile instructions in to chunks or segments such as multiple PUSH operations and static JUMPs. It does this by analysing the opcodes and attempts to match certain regions to known sets. Whenever the optimiser finds said segments it creates a new instruction and replaces the first occurrence in the sequence.

Index

Constants

This section is empty.

Variables

View Source 
var (
	Pow256 = common.BigPow(2, 256) // Pow256 is 2**256

	U256 = common.U256 // Shortcut to common.U256
	S256 = common.S256 // Shortcut to common.S256

	Zero = common.Big0 // Shortcut to common.Big0
	One  = common.Big1 // Shortcut to common.Big1

)
View Source 
var (
	GasQuickStep   = big.NewInt(2)
	GasFastestStep = big.NewInt(3)
	GasFastStep    = big.NewInt(5)
	GasMidStep     = big.NewInt(8)
	GasSlowStep    = big.NewInt(10)
	GasExtStep     = big.NewInt(20)

	GasReturn = big.NewInt(0)
	GasStop   = big.NewInt(0)

	GasContractByte = big.NewInt(200)
)
View Source 
var (
	EnableJit   bool // Enables the JIT VM
	ForceJit    bool // Force the JIT, skip byte VM
	MaxProgSize int  // Max cache size for JIT Programs
)
View Source 
var Debug bool

Global Debug flag indicating Debug VM (full logging)

View Source 
var DepthError = fmt.Errorf("Max call depth exceeded (%d)", params.CallCreateDepth)
View Source 
var OutOfGasError = errors.New("Out of gas")
View Source 
var Precompiled = PrecompiledContracts()

Precompiled contains the default set of ethereum contracts

Functions

func CompileProgram added in v1.1.0 

func CompileProgram(program *Program) (err error)

CompileProgram compiles the given program and return an error when it fails

func Disasm 

func Disasm(code []byte) []string

func Disassemble 

func Disassemble(script []byte) (asm []string)

Dissassemble dissassembles the byte code and returns the string representation (human readable opcodes).

func GetProgramStatus added in v1.1.0 

func GetProgramStatus(id common.Hash) progStatus

GenProgramStatus returns the status of the given program id

func MatchFn added in v1.3.1 

func MatchFn(input, match []OpCode, matcherFn func(int) bool)

MatchFn searcher for match in the given input and calls matcheFn if it finds an appropriate match. matcherFn yields the starting position in the input. MatchFn will continue to search for a match until it reacher the end of the buffer or if matcherFn return false.

func PrecompiledContracts 

func PrecompiledContracts() map[string]*PrecompiledAccount

PrecompiledContracts returns the default set of precompiled ethereum contracts defined by the ethereum yellow paper.

func RunProgram added in v1.1.0 

func RunProgram(program *Program, env Environment, contract *Contract, input []byte) ([]byte, error)

RunProgram runs the program given the enviroment and contract and returns an error if the execution failed (non-consensus)

func SetJITCacheSize added in v1.1.0 

func SetJITCacheSize(size int)

SetJITCacheSize recreates the program cache with the max given size. Setting a new cache is **not** thread safe. Use with caution.

func StdErrFormat 

func StdErrFormat(logs []StructLog)

StdErrFormat formats a slice of StructLogs to human readable format

Types

type Account 

type Account interface {
	SubBalance(amount *big.Int)
	AddBalance(amount *big.Int)
	SetBalance(*big.Int)
	SetNonce(uint64)
	Balance() *big.Int
	Address() common.Address
	ReturnGas(*big.Int, *big.Int)
	SetCode([]byte)
}

type Contract added in v1.3.1 

type Contract struct {
	Code     []byte
	Input    []byte
	CodeAddr *common.Address

	Gas, UsedGas, Price *big.Int

	Args []byte
	// contains filtered or unexported fields
}

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

func NewContract added in v1.3.1 

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

Create a new context for the given data items.

func (*Contract) Address added in v1.3.1 

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

Address returns the contracts address

func (*Contract) GetByte added in v1.3.1 

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

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

func (*Contract) GetOp added in v1.3.1 

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

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

func (*Contract) Return added in v1.3.1 

func (c *Contract) Return(ret []byte) []byte

Return returns the given ret argument and returns any remaining gas to the caller

func (*Contract) ReturnGas added in v1.3.1 

func (c *Contract) ReturnGas(gas, price *big.Int)

ReturnGas adds the given gas back to itself.

func (*Contract) SetCallCode added in v1.3.1 

func (self *Contract) SetCallCode(addr *common.Address, code []byte)

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

func (*Contract) SetCode added in v1.3.1 

func (self *Contract) SetCode(code []byte)

SetCode sets the code to the contract

func (*Contract) UseGas added in v1.3.1 

func (c *Contract) UseGas(gas *big.Int) (ok bool)

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

type ContractRef added in v1.3.1 

type ContractRef interface {
	ReturnGas(*big.Int, *big.Int)
	Address() common.Address
	SetCode([]byte)
}

ContractRef is a reference to the contract's backing object

type Database added in v1.3.1 

type Database interface {
	GetAccount(common.Address) Account
	CreateAccount(common.Address) Account

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

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

	GetCode(common.Address) []byte
	SetCode(common.Address, []byte)

	AddRefund(*big.Int)
	GetRefund() *big.Int

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

	Delete(common.Address) bool
	Exist(common.Address) bool
	IsDeleted(common.Address) bool
}

Database is a EVM database for full state querying

type Environment 

type Environment interface {
	// The state database
	Db() Database
	// Creates a restorable snapshot
	MakeSnapshot() Database
	// Set database to previous snapshot
	SetSnapshot(Database)
	// Address of the original invoker (first occurance of the VM invoker)
	Origin() common.Address
	// The block number this VM is invoken on
	BlockNumber() *big.Int
	// The n'th hash ago from this block number
	GetHash(uint64) common.Hash
	// The handler's address
	Coinbase() common.Address
	// The current time (block time)
	Time() *big.Int
	// Difficulty set on the current block
	Difficulty() *big.Int
	// The gas limit of the block
	GasLimit() *big.Int
	// Determines whether it's possible to transact
	CanTransfer(from common.Address, balance *big.Int) bool
	// Transfers amount from one account to the other
	Transfer(from, to Account, amount *big.Int)
	// Adds a LOG to the state
	AddLog(*Log)
	// Adds a structured log to the env
	AddStructLog(StructLog)
	// Returns all coalesced structured logs
	StructLogs() []StructLog

	// Type of the VM
	VmType() Type

	// Current calling depth
	Depth() int
	SetDepth(i int)

	// Call another contract
	Call(me ContractRef, addr common.Address, data []byte, gas, price, value *big.Int) ([]byte, error)
	// Take another's contract code and execute within our own context
	CallCode(me ContractRef, addr common.Address, data []byte, gas, price, value *big.Int) ([]byte, error)
	// Create a new contract
	Create(me ContractRef, data []byte, gas, price, value *big.Int) ([]byte, common.Address, error)
}

Environment is an EVM requirement and helper which allows access to outside information such as states.

type Log added in v1.3.1 

type Log struct {
	// Consensus fields
	Address common.Address
	Topics  []common.Hash
	Data    []byte

	// Derived fields (don't reorder!)
	BlockNumber uint64
	TxHash      common.Hash
	TxIndex     uint
	BlockHash   common.Hash
	Index       uint
}

func NewLog added in v1.3.1 

func NewLog(address common.Address, topics []common.Hash, data []byte, number uint64) *Log

func (*Log) DecodeRLP added in v1.3.1 

func (l *Log) DecodeRLP(s *rlp.Stream) error

func (*Log) EncodeRLP added in v1.3.1 

func (l *Log) EncodeRLP(w io.Writer) error

func (*Log) String added in v1.3.1 

func (l *Log) String() string

type LogForStorage added in v1.3.1 

type LogForStorage Log

LogForStorage is a wrapper around a Log that flattens and parses the entire content of a log, as opposed to only the consensus fields originally (by hiding the rlp interface methods).

type Logs added in v1.3.1 

type Logs []*Log

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

func (*Memory) Data 

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

Data returns the backing slice

func (*Memory) Get 

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

Get returns offset + size as a new slice

func (*Memory) GetPtr 

func (self *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()

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

type OpCode 

type OpCode byte

OpCode is an EVM opcode 

const (
	// 0x0 range - arithmetic ops
	STOP OpCode = iota
	ADD
	MUL
	SUB
	DIV
	SDIV
	MOD
	SMOD
	ADDMOD
	MULMOD
	EXP
	SIGNEXTEND
)
const (
	LT OpCode = iota + 0x10
	GT
	SLT
	SGT
	EQ
	ISZERO
	AND
	OR
	XOR
	NOT
	BYTE

	SHA3 = 0x20
)
const (
	// 0x30 range - closure state
	ADDRESS OpCode = 0x30 + iota
	BALANCE
	ORIGIN
	CALLER
	CALLVALUE
	CALLDATALOAD
	CALLDATASIZE
	CALLDATACOPY
	CODESIZE
	CODECOPY
	GASPRICE
	EXTCODESIZE
	EXTCODECOPY
)
const (

	// 0x40 range - block operations
	BLOCKHASH OpCode = 0x40 + iota
	COINBASE
	TIMESTAMP
	NUMBER
	DIFFICULTY
	GASLIMIT
)
const (
	// 0x50 range - 'storage' and execution
	POP OpCode = 0x50 + iota
	MLOAD
	MSTORE
	MSTORE8
	SLOAD
	SSTORE
	JUMP
	JUMPI
	PC
	MSIZE
	GAS
	JUMPDEST
)
const (
	// 0x60 range
	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
)
const (
	LOG0 OpCode = 0xa0 + iota
	LOG1
	LOG2
	LOG3
	LOG4
)
const (
	PUSH OpCode = 0xb0 + iota
	DUP
	SWAP
)

unofficial opcodes used for parsing 

const (
	// 0xf0 range - closures
	CREATE OpCode = 0xf0 + iota
	CALL
	CALLCODE
	RETURN

	SUICIDE = 0xff
)

func Parse added in v1.3.1 

func Parse(code []byte) (opcodes []OpCode)

Parse parses all opcodes from the given code byte slice. This function performs no error checking and may return non-existing opcodes.

func StringToOp 

func StringToOp(str string) OpCode

func (OpCode) IsPush added in v1.3.1 

func (op OpCode) IsPush() bool

func (OpCode) IsStaticJump added in v1.3.1 

func (op OpCode) IsStaticJump() bool

func (OpCode) String 

func (o OpCode) String() string

type PrecompiledAccount 

type PrecompiledAccount struct {
	Gas func(l int) *big.Int
	// contains filtered or unexported fields
}

PrecompiledAccount represents a native ethereum contract

func (PrecompiledAccount) Call 

func (self PrecompiledAccount) Call(in []byte) []byte

Call calls the native function

type Program added in v1.1.0 

type Program struct {
	Id common.Hash // Id of the program
	// contains filtered or unexported fields
}

Program is a compiled program for the JIT VM and holds all required for running a compiled JIT program.

func GetProgram added in v1.1.0 

func GetProgram(id common.Hash) *Program

GetProgram returns the program by id or nil when non-existent

func NewProgram added in v1.1.0 

func NewProgram(code []byte) *Program

NewProgram returns a new JIT program

type StructLog 

type StructLog struct {
	Pc      uint64
	Op      OpCode
	Gas     *big.Int
	GasCost *big.Int
	Memory  []byte
	Stack   []*big.Int
	Storage map[common.Hash][]byte
	Err     error
}

StructLog is emited to the Environment each cycle and lists information about the curent internal state prior to the execution of the statement.

type Type 

type Type byte

Type is the VM type accepted by **NewVm** 

const (
	StdVmTy Type = iota // Default standard VM
	JitVmTy             // LLVM JIT VM
	MaxVmTy
)

type VirtualMachine 

type VirtualMachine interface {
	Env() Environment
	Run(*Contract, []byte) ([]byte, error)
}

VirtualMachine is an EVM interface

func NewJitVm 

func NewJitVm(env Environment) VirtualMachine

func NewVm 

func NewVm(env Environment) VirtualMachine

NewVm returns a new VM based on the Environment

type Vm 

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

Vm is an EVM and implements VirtualMachine

func New 

func New(env Environment) *Vm

New returns a new Vm

func (*Vm) Env 

func (self *Vm) Env() Environment

Environment returns the current workable state of the VM

func (*Vm) Run 

func (self *Vm) Run(contract *Contract, input []byte) (ret []byte, err error)

Run loops and evaluates the contract's code with the given input data

func (*Vm) RunPrecompiled 

func (self *Vm) RunPrecompiled(p *PrecompiledAccount, input []byte, contract *Contract) (ret []byte, err error)

RunPrecompile runs and evaluate the output of a precompiled contract defined in contracts.go

Source Files

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