package vm
import (
"fmt"
"math/big"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/state"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/logger/glog"
"github.com/ethereum/go-ethereum/params"
)
type Vm struct {
env Environment
logTy byte
logStr string
err error
// For logging
debug bool
BreakPoints []int64
Stepping bool
Fn string
Recoverable bool
// Will be called before the vm returns
After func(*Context, error)
}
func New(env Environment) *Vm {
lt := LogTyPretty
return &Vm{debug: Debug, env: env, logTy: lt, Recoverable: true}
}
func (self *Vm) Run(context *Context, callData []byte) (ret []byte, err error) {
self.env.SetDepth(self.env.Depth() + 1)
defer self.env.SetDepth(self.env.Depth() - 1)
var (
caller = context.caller
code = context.Code
value = context.value
price = context.Price
)
self.Printf("(%d) (%x) %x (code=%d) gas: %v (d) %x", self.env.Depth(), caller.Address().Bytes()[:4], context.Address(), len(code), context.Gas, callData).Endl()
// 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 self.After != nil {
self.After(context, err)
}
if err != nil {
self.Printf(" %v", err).Endl()
// In case of a VM exception (known exceptions) all gas consumed (panics NOT included).
context.UseGas(context.Gas)
ret = context.Return(nil)
}
}()
if context.CodeAddr != nil {
if p := Precompiled[context.CodeAddr.Str()]; p != nil {
return self.RunPrecompiled(p, callData, context)
}
}
var (
op OpCode
destinations = analyseJumpDests(context.Code)
mem = NewMemory()
stack = newStack()
pc = new(big.Int)
statedb = self.env.State()
jump = func(from *big.Int, to *big.Int) error {
nop := context.GetOp(to)
if !destinations.Has(to) {
return fmt.Errorf("invalid jump destination (%v) %v", nop, to)
}
self.Printf(" ~> %v", to)
pc = to
self.Endl()
return nil
}
)
// Don't bother with the execution if there's no code.
if len(code) == 0 {
return context.Return(nil), nil
}
for {
// The base for all big integer arithmetic
base := new(big.Int)
// Get the memory location of pc
op = context.GetOp(pc)
self.Printf("(pc) %-3d -o- %-14s (m) %-4d (s) %-4d ", pc, op.String(), mem.Len(), stack.len())
newMemSize, gas, err := self.calculateGasAndSize(context, caller, op, statedb, mem, stack)
if err != nil {
return nil, err
}
self.Printf("(g) %-3v (%v)", gas, context.Gas)
if !context.UseGas(gas) {
self.Endl()
tmp := new(big.Int).Set(context.Gas)
context.UseGas(context.Gas)
return context.Return(nil), OOG(gas, tmp)
}
mem.Resize(newMemSize.Uint64())
switch op {
case ADD:
x, y := stack.pop(), stack.pop()
self.Printf(" %v + %v", y, x)
base.Add(x, y)
U256(base)
self.Printf(" = %v", base)
// pop result back on the stack
stack.push(base)
case SUB:
x, y := stack.pop(), stack.pop()
self.Printf(" %v - %v", x, y)
base.Sub(x, y)
U256(base)
self.Printf(" = %v", base)
// pop result back on the stack
stack.push(base)
case MUL:
x, y := stack.pop(), stack.pop()
self.Printf(" %v * %v", y, x)
base.Mul(x, y)
U256(base)
self.Printf(" = %v", base)
// pop result back on the stack
stack.push(base)
case DIV:
x, y := stack.pop(), stack.pop()
self.Printf(" %v / %v", x, y)
if y.Cmp(common.Big0) != 0 {
base.Div(x, y)
}
U256(base)
self.Printf(" = %v", base)
// pop result back on the stack
stack.push(base)
case SDIV:
x, y := S256(stack.pop()), S256(stack.pop())
self.Printf(" %v / %v", x, y)
if y.Cmp(common.Big0) == 0 {
base.Set(common.Big0)
} else {
n := new(big.Int)
if new(big.Int).Mul(x, y).Cmp(common.Big0) < 0 {
n.SetInt64(-1)
} else {
n.SetInt64(1)
}
base.Div(x.Abs(x), y.Abs(y)).Mul(base, n)
U256(base)
}
self.Printf(" = %v", base)
stack.push(base)
case MOD:
x, y := stack.pop(), stack.pop()
self.Printf(" %v %% %v", x, y)
if y.Cmp(common.Big0) == 0 {
base.Set(common.Big0)
} else {
base.Mod(x, y)
}
U256(base)
self.Printf(" = %v", base)
stack.push(base)
case SMOD:
x, y := S256(stack.pop()), S256(stack.pop())
self.Printf(" %v %% %v", x, y)
if y.Cmp(common.Big0) == 0 {
base.Set(common.Big0)
} else {
n := new(big.Int)
if x.Cmp(common.Big0) < 0 {
n.SetInt64(-1)
} else {
n.SetInt64(1)
}
base.Mod(x.Abs(x), y.Abs(y)).Mul(base, n)
U256(base)
}
self.Printf(" = %v", base)
stack.push(base)
case EXP:
x, y := stack.pop(), stack.pop()
self.Printf(" %v ** %v", x, y)
base.Exp(x, y, Pow256)
U256(base)
self.Printf(" = %v", base)
stack.push(base)
case SIGNEXTEND:
back := stack.pop()
if back.Cmp(big.NewInt(31)) < 0 {
bit := uint(back.Uint64()*8 + 7)
num := stack.pop()
mask := new(big.Int).Lsh(common.Big1, bit)
mask.Sub(mask, common.Big1)
if common.BitTest(num, int(bit)) {
num.Or(num, mask.Not(mask))
} else {
num.And(num, mask)
}
num = U256(num)
self.Printf(" = %v", num)
stack.push(num)
}
case NOT:
stack.push(U256(new(big.Int).Not(stack.pop())))
case LT:
x, y := stack.pop(), stack.pop()
self.Printf(" %v < %v", x, y)
// x < y
if x.Cmp(y) < 0 {
stack.push(common.BigTrue)
} else {
stack.push(common.BigFalse)
}
case GT:
x, y := stack.pop(), stack.pop()
self.Printf(" %v > %v", x, y)
// x > y
if x.Cmp(y) > 0 {
stack.push(common.BigTrue)
} else {
stack.push(common.BigFalse)
}
case SLT:
x, y := S256(stack.pop()), S256(stack.pop())
self.Printf(" %v < %v", x, y)
// x < y
if x.Cmp(S256(y)) < 0 {
stack.push(common.BigTrue)
} else {
stack.push(common.BigFalse)
}
case SGT:
x, y := S256(stack.pop()), S256(stack.pop())
self.Printf(" %v > %v", x, y)
// x > y
if x.Cmp(y) > 0 {
stack.push(common.BigTrue)
} else {
stack.push(common.BigFalse)
}
case EQ:
x, y := stack.pop(), stack.pop()
self.Printf(" %v == %v", y, x)
// x == y
if x.Cmp(y) == 0 {
stack.push(common.BigTrue)
} else {
stack.push(common.BigFalse)
}
case ISZERO:
x := stack.pop()
if x.Cmp(common.BigFalse) > 0 {
stack.push(common.BigFalse)
} else {
stack.push(common.BigTrue)
}
case AND:
x, y := stack.pop(), stack.pop()
self.Printf(" %v & %v", y, x)
stack.push(base.And(x, y))
case OR:
x, y := stack.pop(), stack.pop()
self.Printf(" %v | %v", x, y)
stack.push(base.Or(x, y))
case XOR:
x, y := stack.pop(), stack.pop()
self.Printf(" %v ^ %v", x, y)
stack.push(base.Xor(x, y))
case BYTE:
th, val := stack.pop(), stack.pop()
if th.Cmp(big.NewInt(32)) < 0 {
byt := big.NewInt(int64(common.LeftPadBytes(val.Bytes(), 32)[th.Int64()]))
base.Set(byt)
} else {
base.Set(common.BigFalse)
}
self.Printf(" => 0x%x", base.Bytes())
stack.push(base)
case ADDMOD:
x := stack.pop()
y := stack.pop()
z := stack.pop()
if z.Cmp(Zero) > 0 {
add := new(big.Int).Add(x, y)
base.Mod(add, z)
base = U256(base)
}
self.Printf(" %v + %v %% %v = %v", x, y, z, base)
stack.push(base)
case MULMOD:
x := stack.pop()
y := stack.pop()
z := stack.pop()
if z.Cmp(Zero) > 0 {
mul := new(big.Int).Mul(x, y)
base.Mod(mul, z)
U256(base)
}
self.Printf(" %v + %v %% %v = %v", x, y, z, base)
stack.push(base)
case SHA3:
offset, size := stack.pop(), stack.pop()
data := crypto.Sha3(mem.Get(offset.Int64(), size.Int64()))
stack.push(common.BigD(data))
self.Printf(" => (%v) %x", size, data)
case ADDRESS:
stack.push(common.Bytes2Big(context.Address().Bytes()))
self.Printf(" => %x", context.Address())
case BALANCE:
addr := common.BigToAddress(stack.pop())
balance := statedb.GetBalance(addr)
stack.push(balance)
self.Printf(" => %v (%x)", balance, addr)
case ORIGIN:
origin := self.env.Origin()
stack.push(origin.Big())
self.Printf(" => %x", origin)
case CALLER:
caller := context.caller.Address()
stack.push(common.Bytes2Big(caller.Bytes()))
self.Printf(" => %x", caller)
case CALLVALUE:
stack.push(value)
self.Printf(" => %v", value)
case CALLDATALOAD:
data := getData(callData, stack.pop(), common.Big32)
self.Printf(" => 0x%x", data)
stack.push(common.Bytes2Big(data))
case CALLDATASIZE:
l := int64(len(callData))
stack.push(big.NewInt(l))
self.Printf(" => %d", l)
case CALLDATACOPY:
var (
mOff = stack.pop()
cOff = stack.pop()
l = stack.pop()
)
data := getData(callData, cOff, l)
mem.Set(mOff.Uint64(), l.Uint64(), data)
self.Printf(" => [%v, %v, %v]", mOff, cOff, l)
case CODESIZE, EXTCODESIZE:
var code []byte
if op == EXTCODESIZE {
addr := common.BigToAddress(stack.pop())
code = statedb.GetCode(addr)
} else {
code = context.Code
}
l := big.NewInt(int64(len(code)))
stack.push(l)
self.Printf(" => %d", l)
case CODECOPY, EXTCODECOPY:
var code []byte
if op == EXTCODECOPY {
addr := common.BigToAddress(stack.pop())
code = statedb.GetCode(addr)
} else {
code = context.Code
}
var (
mOff = stack.pop()
cOff = stack.pop()
l = stack.pop()
)
codeCopy := getData(code, cOff, l)
mem.Set(mOff.Uint64(), l.Uint64(), codeCopy)
self.Printf(" => [%v, %v, %v] %x", mOff, cOff, l, codeCopy)
case GASPRICE:
stack.push(context.Price)
self.Printf(" => %x", context.Price)
case BLOCKHASH:
num := stack.pop()
n := new(big.Int).Sub(self.env.BlockNumber(), common.Big257)
if num.Cmp(n) > 0 && num.Cmp(self.env.BlockNumber()) < 0 {
stack.push(self.env.GetHash(num.Uint64()).Big())
} else {
stack.push(common.Big0)
}
self.Printf(" => 0x%x", stack.peek().Bytes())
case COINBASE:
coinbase := self.env.Coinbase()
stack.push(coinbase.Big())
self.Printf(" => 0x%x", coinbase)
case TIMESTAMP:
time := self.env.Time()
stack.push(big.NewInt(time))
self.Printf(" => 0x%x", time)
case NUMBER:
number := self.env.BlockNumber()
stack.push(U256(number))
self.Printf(" => 0x%x", number.Bytes())
case DIFFICULTY:
difficulty := self.env.Difficulty()
stack.push(difficulty)
self.Printf(" => 0x%x", difficulty.Bytes())
case GASLIMIT:
self.Printf(" => %v", self.env.GasLimit())
stack.push(self.env.GasLimit())
case PUSH1, 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:
a := big.NewInt(int64(op - PUSH1 + 1))
byts := getData(code, new(big.Int).Add(pc, big.NewInt(1)), a)
// push value to stack
stack.push(common.Bytes2Big(byts))
pc.Add(pc, a)
self.Printf(" => 0x%x", byts)
case POP:
stack.pop()
case DUP1, DUP2, DUP3, DUP4, DUP5, DUP6, DUP7, DUP8, DUP9, DUP10, DUP11, DUP12, DUP13, DUP14, DUP15, DUP16:
n := int(op - DUP1 + 1)
stack.dup(n)
self.Printf(" => [%d] 0x%x", n, stack.peek().Bytes())
case SWAP1, SWAP2, SWAP3, SWAP4, SWAP5, SWAP6, SWAP7, SWAP8, SWAP9, SWAP10, SWAP11, SWAP12, SWAP13, SWAP14, SWAP15, SWAP16:
n := int(op - SWAP1 + 2)
stack.swap(n)
self.Printf(" => [%d]", n)
case LOG0, LOG1, LOG2, LOG3, LOG4:
n := int(op - LOG0)
topics := make([]common.Hash, n)
mStart, mSize := stack.pop(), stack.pop()
for i := 0; i < n; i++ {
topics[i] = common.BigToHash(stack.pop())
}
data := mem.Get(mStart.Int64(), mSize.Int64())
log := state.NewLog(context.Address(), topics, data, self.env.BlockNumber().Uint64())
self.env.AddLog(log)
self.Printf(" => %v", log)
case MLOAD:
offset := stack.pop()
val := common.BigD(mem.Get(offset.Int64(), 32))
stack.push(val)
self.Printf(" => 0x%x", val.Bytes())
case MSTORE:
// pop value of the stack
mStart, val := stack.pop(), stack.pop()
mem.Set(mStart.Uint64(), 32, common.BigToBytes(val, 256))
self.Printf(" => 0x%x", val)
case MSTORE8:
off, val := stack.pop().Int64(), stack.pop().Int64()
mem.store[off] = byte(val & 0xff)
self.Printf(" => [%v] 0x%x", off, mem.store[off])
case SLOAD:
loc := common.BigToHash(stack.pop())
val := common.Bytes2Big(statedb.GetState(context.Address(), loc))
stack.push(val)
self.Printf(" {0x%x : 0x%x}", loc, val.Bytes())
case SSTORE:
loc := common.BigToHash(stack.pop())
val := stack.pop()
statedb.SetState(context.Address(), loc, val)
self.Printf(" {0x%x : 0x%x}", loc, val.Bytes())
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
}
self.Printf(" ~> false")
case JUMPDEST:
case PC:
stack.push(pc)
case MSIZE:
stack.push(big.NewInt(int64(mem.Len())))
case GAS:
stack.push(context.Gas)
self.Printf(" => %x", context.Gas)
case CREATE:
var (
value = stack.pop()
offset, size = stack.pop(), stack.pop()
input = mem.Get(offset.Int64(), size.Int64())
gas = new(big.Int).Set(context.Gas)
addr common.Address
)
self.Endl()
context.UseGas(context.Gas)
ret, suberr, ref := self.env.Create(context, input, gas, price, value)
if suberr != nil {
stack.push(common.BigFalse)
self.Printf(" (*) 0x0 %v", suberr)
} else {
// gas < len(ret) * CreateDataGas == NO_CODE
dataGas := big.NewInt(int64(len(ret)))
dataGas.Mul(dataGas, params.CreateDataGas)
if context.UseGas(dataGas) {
ref.SetCode(ret)
}
addr = ref.Address()
stack.push(addr.Big())
}
case CALL, CALLCODE:
gas := stack.pop()
// pop gas and value of the stack.
addr, value := stack.pop(), stack.pop()
value = U256(value)
// pop input size and offset
inOffset, inSize := stack.pop(), stack.pop()
// pop return size and offset
retOffset, retSize := stack.pop(), stack.pop()
address := common.BigToAddress(addr)
self.Printf(" => %x", address).Endl()
// Get the arguments from the memory
args := mem.Get(inOffset.Int64(), inSize.Int64())
if len(value.Bytes()) > 0 {
gas.Add(gas, params.CallStipend)
}
var (
ret []byte
err error
)
if op == CALLCODE {
ret, err = self.env.CallCode(context, address, args, gas, price, value)
} else {
ret, err = self.env.Call(context, address, args, gas, price, value)
}
if err != nil {
stack.push(common.BigFalse)
self.Printf("%v").Endl()
} else {
stack.push(common.BigTrue)
mem.Set(retOffset.Uint64(), retSize.Uint64(), ret)
}
self.Printf("resume %x (%v)", context.Address(), context.Gas)
case RETURN:
offset, size := stack.pop(), stack.pop()
ret := mem.GetPtr(offset.Int64(), size.Int64())
self.Printf(" => [%v, %v] (%d) 0x%x", offset, size, len(ret), ret).Endl()
return context.Return(ret), nil
case SUICIDE:
receiver := statedb.GetOrNewStateObject(common.BigToAddress(stack.pop()))
balance := statedb.GetBalance(context.Address())
self.Printf(" => (%x) %v", receiver.Address().Bytes()[:4], balance)
receiver.AddBalance(balance)
statedb.Delete(context.Address())
fallthrough
case STOP: // Stop the context
self.Endl()
return context.Return(nil), nil
default:
self.Printf("(pc) %-3v Invalid opcode %x\n", pc, op).Endl()
return nil, fmt.Errorf("Invalid opcode %x", op)
}
pc.Add(pc, One)
self.Endl()
}
}
func (self *Vm) calculateGasAndSize(context *Context, caller ContextRef, op OpCode, statedb *state.StateDB, 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 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)
case EXP:
gas.Add(gas, new(big.Int).Mul(big.NewInt(int64(len(stack.data[stack.len()-2].Bytes()))), params.ExpByteGas))
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 := statedb.GetState(context.Address(), common.BigToHash(x))
if len(val) == 0 && len(y.Bytes()) > 0 {
// 0 => non 0
g = params.SstoreSetGas
} else if len(val) > 0 && len(y.Bytes()) == 0 {
statedb.Refund(self.env.Origin(), params.SstoreRefundGas)
g = params.SstoreClearGas
} else {
// non 0 => non 0 (or 0 => 0)
g = params.SstoreClearGas
}
gas.Set(g)
case SUICIDE:
if !statedb.IsDeleted(context.Address()) {
statedb.Refund(self.env.Origin(), params.SuicideRefundGas)
}
case MLOAD:
newMemSize = calcMemSize(stack.peek(), u256(32))
case MSTORE8:
newMemSize = calcMemSize(stack.peek(), u256(1))
case MSTORE:
newMemSize = calcMemSize(stack.peek(), u256(32))
case RETURN:
newMemSize = calcMemSize(stack.peek(), stack.data[stack.len()-2])
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))
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))
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))
case 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))
case CREATE:
newMemSize = calcMemSize(stack.data[stack.len()-2], stack.data[stack.len()-3])
case CALL, CALLCODE:
gas.Add(gas, stack.data[stack.len()-1])
if op == CALL {
if self.env.State().GetStateObject(common.BigToAddress(stack.data[stack.len()-2])) == nil {
gas.Add(gas, params.CallNewAccountGas)
}
}
if len(stack.data[stack.len()-3].Bytes()) > 0 {
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)
}
if newMemSize.Cmp(common.Big0) > 0 {
newMemSizeWords := toWordSize(newMemSize)
newMemSize.Mul(newMemSizeWords, u256(32))
if newMemSize.Cmp(u256(int64(mem.Len()))) > 0 {
oldSize := toWordSize(big.NewInt(int64(mem.Len())))
pow := new(big.Int).Exp(oldSize, common.Big2, Zero)
linCoef := new(big.Int).Mul(oldSize, params.MemoryGas)
quadCoef := new(big.Int).Div(pow, params.QuadCoeffDiv)
oldTotalFee := new(big.Int).Add(linCoef, quadCoef)
pow.Exp(newMemSizeWords, common.Big2, Zero)
linCoef = new(big.Int).Mul(newMemSizeWords, params.MemoryGas)
quadCoef = new(big.Int).Div(pow, params.QuadCoeffDiv)
newTotalFee := new(big.Int).Add(linCoef, quadCoef)
fee := new(big.Int).Sub(newTotalFee, oldTotalFee)
gas.Add(gas, fee)
}
}
return newMemSize, gas, nil
}
func (self *Vm) RunPrecompiled(p *PrecompiledAccount, callData []byte, context *Context) (ret []byte, err error) {
gas := p.Gas(len(callData))
if context.UseGas(gas) {
ret = p.Call(callData)
self.Printf("NATIVE_FUNC => %x", ret)
self.Endl()
return context.Return(ret), nil
} else {
self.Printf("NATIVE_FUNC => failed").Endl()
tmp := new(big.Int).Set(context.Gas)
return nil, OOG(gas, tmp)
}
}
func (self *Vm) Printf(format string, v ...interface{}) VirtualMachine {
if self.debug {
self.logStr += fmt.Sprintf(format, v...)
}
return self
}
func (self *Vm) Endl() VirtualMachine {
if self.debug {
glog.V(0).Infoln(self.logStr)
self.logStr = ""
}
return self
}
func (self *Vm) Env() Environment {
return self.env
}