plugeth/core/vm/vm.go
Jeffrey Wilcke 3fc7c97827 core, core/vm: implemented a generic environment (#3348)
Environment is now a struct (not an interface). This
reduces a lot of tech-debt throughout the codebase where a virtual
machine environment had to be implemented in order to test or run it.

The new environment is suitable to be used en the json tests, core
consensus and light client.
2016-12-06 02:16:03 +01:00

468 lines
14 KiB
Go

// 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 (
"fmt"
"math/big"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
"github.com/ethereum/go-ethereum/params"
)
// Config are the configuration options for the EVM
type Config struct {
// Debug enabled debugging EVM options
Debug bool
// EnableJit enabled the JIT VM
EnableJit bool
// ForceJit forces the JIT VM
ForceJit bool
// Tracer is the op code logger
Tracer Tracer
// NoRecursion disabled EVM call, callcode,
// delegate call and create.
NoRecursion bool
}
// EVM is used to run Ethereum based contracts and will utilise the
// passed environment to query external sources for state information.
// The EVM will run the byte code VM or JIT VM based on the passed
// configuration.
type EVM struct {
env *Environment
jumpTable vmJumpTable
cfg Config
gasTable params.GasTable
}
// New returns a new instance of the EVM.
func New(env *Environment, cfg Config) *EVM {
return &EVM{
env: env,
jumpTable: newJumpTable(env.ChainConfig(), env.BlockNumber),
cfg: cfg,
gasTable: env.ChainConfig().GasTable(env.BlockNumber),
}
}
// Run loops and evaluates the contract's code with the given input data
func (evm *EVM) Run(contract *Contract, input []byte) (ret []byte, err error) {
evm.env.Depth++
defer func() { evm.env.Depth-- }()
if contract.CodeAddr != nil {
if p := Precompiled[contract.CodeAddr.Str()]; p != nil {
return evm.RunPrecompiled(p, input, contract)
}
}
// Don't bother with the execution if there's no code.
if len(contract.Code) == 0 {
return nil, nil
}
codehash := contract.CodeHash // codehash is used when doing jump dest caching
if codehash == (common.Hash{}) {
codehash = crypto.Keccak256Hash(contract.Code)
}
var program *Program
if false {
// JIT disabled due to JIT not being Homestead gas reprice ready.
// If the JIT is enabled check the status of the JIT program,
// if it doesn't exist compile a new program in a separate
// goroutine or wait for compilation to finish if the JIT is
// forced.
switch GetProgramStatus(codehash) {
case progReady:
return RunProgram(GetProgram(codehash), evm.env, contract, input)
case progUnknown:
if evm.cfg.ForceJit {
// Create and compile program
program = NewProgram(contract.Code)
perr := CompileProgram(program)
if perr == nil {
return RunProgram(program, evm.env, contract, input)
}
glog.V(logger.Info).Infoln("error compiling program", err)
} else {
// create and compile the program. Compilation
// is done in a separate goroutine
program = NewProgram(contract.Code)
go func() {
err := CompileProgram(program)
if err != nil {
glog.V(logger.Info).Infoln("error compiling program", err)
return
}
}()
}
}
}
var (
caller = contract.caller
code = contract.Code
instrCount = 0
op OpCode // current opcode
mem = NewMemory() // bound memory
stack = newstack() // local stack
// For optimisation reason we're using uint64 as the program counter.
// It's theoretically possible to go above 2^64. The YP defines the PC to be uint256. Practically much less so feasible.
pc = uint64(0) // program counter
// jump evaluates and checks whether the given jump destination is a valid one
// if valid move the `pc` otherwise return an error.
jump = func(from uint64, to *big.Int) error {
if !contract.jumpdests.has(codehash, code, to) {
nop := contract.GetOp(to.Uint64())
return fmt.Errorf("invalid jump destination (%v) %v", nop, to)
}
pc = to.Uint64()
return nil
}
newMemSize *big.Int
cost *big.Int
)
contract.Input = input
// User defer pattern to check for an error and, based on the error being nil or not, use all gas and return.
defer func() {
if err != nil && evm.cfg.Debug {
evm.cfg.Tracer.CaptureState(evm.env, pc, op, contract.Gas, cost, mem, stack, contract, evm.env.Depth, err)
}
}()
if glog.V(logger.Debug) {
glog.Infof("running byte VM %x\n", codehash[:4])
tstart := time.Now()
defer func() {
glog.Infof("byte VM %x done. time: %v instrc: %v\n", codehash[:4], time.Since(tstart), instrCount)
}()
}
for ; ; instrCount++ {
/*
if EnableJit && it%100 == 0 {
if program != nil && progStatus(atomic.LoadInt32(&program.status)) == progReady {
// move execution
fmt.Println("moved", it)
glog.V(logger.Info).Infoln("Moved execution to JIT")
return runProgram(program, pc, mem, stack, evm.env, contract, input)
}
}
*/
// Get the memory location of pc
op = contract.GetOp(pc)
//fmt.Printf("OP %d %v\n", op, op)
// calculate the new memory size and gas price for the current executing opcode
newMemSize, cost, err = calculateGasAndSize(evm.gasTable, evm.env, contract, caller, op, mem, stack)
if err != nil {
return nil, err
}
// Use the calculated gas. When insufficient gas is present, use all gas and return an
// Out Of Gas error
if !contract.UseGas(cost) {
return nil, OutOfGasError
}
// Resize the memory calculated previously
mem.Resize(newMemSize.Uint64())
// Add a log message
if evm.cfg.Debug {
err = evm.cfg.Tracer.CaptureState(evm.env, pc, op, contract.Gas, cost, mem, stack, contract, evm.env.Depth, nil)
if err != nil {
return nil, err
}
}
if opPtr := evm.jumpTable[op]; opPtr.valid {
if opPtr.fn != nil {
opPtr.fn(instruction{}, &pc, evm.env, contract, mem, stack)
} else {
switch op {
case PC:
opPc(instruction{data: new(big.Int).SetUint64(pc)}, &pc, evm.env, contract, mem, stack)
case JUMP:
if err := jump(pc, stack.pop()); err != nil {
return nil, err
}
continue
case JUMPI:
pos, cond := stack.pop(), stack.pop()
if cond.Cmp(common.BigTrue) >= 0 {
if err := jump(pc, pos); err != nil {
return nil, err
}
continue
}
case RETURN:
offset, size := stack.pop(), stack.pop()
ret := mem.GetPtr(offset.Int64(), size.Int64())
return ret, nil
case SUICIDE:
opSuicide(instruction{}, nil, evm.env, contract, mem, stack)
fallthrough
case STOP: // Stop the contract
return nil, nil
}
}
} else {
return nil, fmt.Errorf("Invalid opcode %x", op)
}
pc++
}
}
// calculateGasAndSize calculates the required given the opcode and stack items calculates the new memorysize for
// the operation. This does not reduce gas or resizes the memory.
func calculateGasAndSize(gasTable params.GasTable, env *Environment, contract *Contract, caller ContractRef, op OpCode, mem *Memory, stack *Stack) (*big.Int, *big.Int, error) {
var (
gas = new(big.Int)
newMemSize *big.Int = new(big.Int)
)
err := baseCheck(op, stack, gas)
if err != nil {
return nil, nil, err
}
// stack Check, memory resize & gas phase
switch op {
case SUICIDE:
// EIP150 homestead gas reprice fork:
if gasTable.CreateBySuicide != nil {
gas.Set(gasTable.Suicide)
var (
address = common.BigToAddress(stack.data[len(stack.data)-1])
eip158 = env.ChainConfig().IsEIP158(env.BlockNumber)
)
if eip158 {
// if empty and transfers value
if env.StateDB.Empty(address) && env.StateDB.GetBalance(contract.Address()).BitLen() > 0 {
gas.Add(gas, gasTable.CreateBySuicide)
}
} else if !env.StateDB.Exist(address) {
gas.Add(gas, gasTable.CreateBySuicide)
}
}
if !env.StateDB.HasSuicided(contract.Address()) {
env.StateDB.AddRefund(params.SuicideRefundGas)
}
case EXTCODESIZE:
gas.Set(gasTable.ExtcodeSize)
case BALANCE:
gas.Set(gasTable.Balance)
case SLOAD:
gas.Set(gasTable.SLoad)
case SWAP1, SWAP2, SWAP3, SWAP4, SWAP5, SWAP6, SWAP7, SWAP8, SWAP9, SWAP10, SWAP11, SWAP12, SWAP13, SWAP14, SWAP15, SWAP16:
n := int(op - SWAP1 + 2)
err := stack.require(n)
if err != nil {
return nil, nil, err
}
gas.Set(GasFastestStep)
case DUP1, DUP2, DUP3, DUP4, DUP5, DUP6, DUP7, DUP8, DUP9, DUP10, DUP11, DUP12, DUP13, DUP14, DUP15, DUP16:
n := int(op - DUP1 + 1)
err := stack.require(n)
if err != nil {
return nil, nil, err
}
gas.Set(GasFastestStep)
case LOG0, LOG1, LOG2, LOG3, LOG4:
n := int(op - LOG0)
err := stack.require(n + 2)
if err != nil {
return nil, nil, err
}
mSize, mStart := stack.data[stack.len()-2], stack.data[stack.len()-1]
gas.Add(gas, params.LogGas)
gas.Add(gas, new(big.Int).Mul(big.NewInt(int64(n)), params.LogTopicGas))
gas.Add(gas, new(big.Int).Mul(mSize, params.LogDataGas))
newMemSize = calcMemSize(mStart, mSize)
quadMemGas(mem, newMemSize, gas)
case EXP:
expByteLen := int64((stack.data[stack.len()-2].BitLen() + 7) / 8)
gas.Add(gas, new(big.Int).Mul(big.NewInt(expByteLen), gasTable.ExpByte))
case SSTORE:
err := stack.require(2)
if err != nil {
return nil, nil, err
}
var g *big.Int
y, x := stack.data[stack.len()-2], stack.data[stack.len()-1]
val := env.StateDB.GetState(contract.Address(), common.BigToHash(x))
// This checks for 3 scenario's and calculates gas accordingly
// 1. From a zero-value address to a non-zero value (NEW VALUE)
// 2. From a non-zero value address to a zero-value address (DELETE)
// 3. From a non-zero to a non-zero (CHANGE)
if common.EmptyHash(val) && !common.EmptyHash(common.BigToHash(y)) {
// 0 => non 0
g = params.SstoreSetGas
} else if !common.EmptyHash(val) && common.EmptyHash(common.BigToHash(y)) {
env.StateDB.AddRefund(params.SstoreRefundGas)
g = params.SstoreClearGas
} else {
// non 0 => non 0 (or 0 => 0)
g = params.SstoreResetGas
}
gas.Set(g)
case MLOAD:
newMemSize = calcMemSize(stack.peek(), u256(32))
quadMemGas(mem, newMemSize, gas)
case MSTORE8:
newMemSize = calcMemSize(stack.peek(), u256(1))
quadMemGas(mem, newMemSize, gas)
case MSTORE:
newMemSize = calcMemSize(stack.peek(), u256(32))
quadMemGas(mem, newMemSize, gas)
case RETURN:
newMemSize = calcMemSize(stack.peek(), stack.data[stack.len()-2])
quadMemGas(mem, newMemSize, gas)
case SHA3:
newMemSize = calcMemSize(stack.peek(), stack.data[stack.len()-2])
words := toWordSize(stack.data[stack.len()-2])
gas.Add(gas, words.Mul(words, params.Sha3WordGas))
quadMemGas(mem, newMemSize, gas)
case CALLDATACOPY:
newMemSize = calcMemSize(stack.peek(), stack.data[stack.len()-3])
words := toWordSize(stack.data[stack.len()-3])
gas.Add(gas, words.Mul(words, params.CopyGas))
quadMemGas(mem, newMemSize, gas)
case CODECOPY:
newMemSize = calcMemSize(stack.peek(), stack.data[stack.len()-3])
words := toWordSize(stack.data[stack.len()-3])
gas.Add(gas, words.Mul(words, params.CopyGas))
quadMemGas(mem, newMemSize, gas)
case EXTCODECOPY:
gas.Set(gasTable.ExtcodeCopy)
newMemSize = calcMemSize(stack.data[stack.len()-2], stack.data[stack.len()-4])
words := toWordSize(stack.data[stack.len()-4])
gas.Add(gas, words.Mul(words, params.CopyGas))
quadMemGas(mem, newMemSize, gas)
case CREATE:
newMemSize = calcMemSize(stack.data[stack.len()-2], stack.data[stack.len()-3])
quadMemGas(mem, newMemSize, gas)
case CALL, CALLCODE:
gas.Set(gasTable.Calls)
transfersValue := stack.data[len(stack.data)-3].BitLen() > 0
if op == CALL {
var (
address = common.BigToAddress(stack.data[len(stack.data)-2])
eip158 = env.ChainConfig().IsEIP158(env.BlockNumber)
)
if eip158 {
if env.StateDB.Empty(address) && transfersValue {
gas.Add(gas, params.CallNewAccountGas)
}
} else if !env.StateDB.Exist(address) {
gas.Add(gas, params.CallNewAccountGas)
}
}
if transfersValue {
gas.Add(gas, params.CallValueTransferGas)
}
x := calcMemSize(stack.data[stack.len()-6], stack.data[stack.len()-7])
y := calcMemSize(stack.data[stack.len()-4], stack.data[stack.len()-5])
newMemSize = common.BigMax(x, y)
quadMemGas(mem, newMemSize, gas)
cg := callGas(gasTable, contract.Gas, gas, stack.data[stack.len()-1])
// Replace the stack item with the new gas calculation. This means that
// either the original item is left on the stack or the item is replaced by:
// (availableGas - gas) * 63 / 64
// We replace the stack item so that it's available when the opCall instruction is
// called. This information is otherwise lost due to the dependency on *current*
// available gas.
stack.data[stack.len()-1] = cg
gas.Add(gas, cg)
case DELEGATECALL:
gas.Set(gasTable.Calls)
x := calcMemSize(stack.data[stack.len()-5], stack.data[stack.len()-6])
y := calcMemSize(stack.data[stack.len()-3], stack.data[stack.len()-4])
newMemSize = common.BigMax(x, y)
quadMemGas(mem, newMemSize, gas)
cg := callGas(gasTable, contract.Gas, gas, stack.data[stack.len()-1])
// Replace the stack item with the new gas calculation. This means that
// either the original item is left on the stack or the item is replaced by:
// (availableGas - gas) * 63 / 64
// We replace the stack item so that it's available when the opCall instruction is
// called.
stack.data[stack.len()-1] = cg
gas.Add(gas, cg)
}
return newMemSize, gas, nil
}
// RunPrecompile runs and evaluate the output of a precompiled contract defined in contracts.go
func (evm *EVM) RunPrecompiled(p *PrecompiledAccount, input []byte, contract *Contract) (ret []byte, err error) {
gas := p.Gas(len(input))
if contract.UseGas(gas) {
ret = p.Call(input)
return ret, nil
} else {
return nil, OutOfGasError
}
}