plugeth/core/vm/interpreter.go
Jeffrey Wilcke c12f4df910 params: core, core/vm, miner: 64bit gas instructions
Reworked the EVM gas instructions to use 64bit integers rather than
arbitrary size big ints. All gas operations, be it additions,
multiplications or divisions, are checked and guarded against 64 bit
integer overflows.

In additon, most of the protocol paramaters in the params package have
been converted to uint64 and are now constants rather than variables.

* common/math: added overflow check ops
* core: vmenv, env renamed to evm
* eth, internal/ethapi, les: unmetered eth_call and cancel methods
* core/vm: implemented big.Int pool for evm instructions
* core/vm: unexported intPool methods & verification methods
* core/vm: added memoryGasCost overflow check and test
2017-02-13 21:44:25 +01:00

209 lines
6.6 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"
"sync/atomic"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/math"
"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 Interpreter
type Config struct {
// Debug enabled debugging Interpreter 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 Interpreter call, callcode,
// delegate call and create.
NoRecursion bool
// Disable gas metering
DisableGasMetering bool
// Enable recording of SHA3/keccak preimages
EnablePreimageRecording bool
// JumpTable contains the EVM instruction table. This
// may me left uninitialised and will be set the default
// table.
JumpTable [256]operation
}
// 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 or JIT VM based on the passed
// configuration.
type Interpreter struct {
env *EVM
cfg Config
gasTable params.GasTable
intPool *intPool
}
// NewInterpreter returns a new instance of the Interpreter.
func NewInterpreter(env *EVM, cfg Config) *Interpreter {
// We use the STOP instruction whether to see
// the jump table was initialised. If it was not
// we'll set the default jump table.
if !cfg.JumpTable[STOP].valid {
cfg.JumpTable = defaultJumpTable
}
return &Interpreter{
env: env,
cfg: cfg,
gasTable: env.ChainConfig().GasTable(env.BlockNumber),
intPool: newIntPool(),
}
}
// Run loops and evaluates the contract's code with the given input data
func (evm *Interpreter) Run(contract *Contract, input []byte) (ret []byte, err error) {
evm.env.depth++
defer func() { evm.env.depth-- }()
if contract.CodeAddr != nil {
if p := PrecompiledContracts[*contract.CodeAddr]; p != nil {
return RunPrecompiledContract(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 (
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
cost uint64
)
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 {
// XXX For debugging
//fmt.Printf("%04d: %8v cost = %-8d stack = %-8d ERR = %v\n", pc, op, cost, stack.len(), err)
// TODO update the tracer
g, c := new(big.Int).SetUint64(contract.Gas), new(big.Int).SetUint64(cost)
evm.cfg.Tracer.CaptureState(evm.env, pc, op, g, c, mem, stack, contract, evm.env.depth, err)
}
}()
if glog.V(logger.Debug) {
glog.Infof("evm running: %x\n", codehash[:4])
tstart := time.Now()
defer func() {
glog.Infof("evm done: %x. time: %v\n", codehash[:4], time.Since(tstart))
}()
}
// The Interpreter main run loop (contextual). This loop runs until either an
// explicit STOP, RETURN or SELFDESTRUCT is executed, an error occurred during
// the execution of one of the operations or until the evm.done is set by
// the parent context.Context.
for atomic.LoadInt32(&evm.env.abort) == 0 {
// Get the memory location of pc
op = contract.GetOp(pc)
// get the operation from the jump table matching the opcode
operation := evm.cfg.JumpTable[op]
// if the op is invalid abort the process and return an error
if !operation.valid {
return nil, fmt.Errorf("invalid opcode %x", op)
}
// validate the stack and make sure there enough stack items available
// to perform the operation
if err := operation.validateStack(stack); err != nil {
return nil, err
}
var memorySize uint64
// calculate the new memory size and expand the memory to fit
// the operation
if operation.memorySize != nil {
memSize, overflow := bigUint64(operation.memorySize(stack))
if overflow {
return nil, errGasUintOverflow
}
// memory is expanded in words of 32 bytes. Gas
// is also calculated in words.
if memorySize, overflow = math.SafeMul(toWordSize(memSize), 32); overflow {
return nil, errGasUintOverflow
}
}
if !evm.cfg.DisableGasMetering {
// consume the gas and return an error if not enough gas is available.
// cost is explicitly set so that the capture state defer method cas get the proper cost
cost, err = operation.gasCost(evm.gasTable, evm.env, contract, stack, mem, memorySize)
if err != nil || !contract.UseGas(cost) {
return nil, ErrOutOfGas
}
}
if memorySize > 0 {
mem.Resize(memorySize)
}
if evm.cfg.Debug {
g, c := new(big.Int).SetUint64(contract.Gas), new(big.Int).SetUint64(cost)
evm.cfg.Tracer.CaptureState(evm.env, pc, op, g, c, mem, stack, contract, evm.env.depth, err)
}
// XXX For debugging
//fmt.Printf("%04d: %8v cost = %-8d stack = %-8d\n", pc, op, cost, stack.len())
// execute the operation
res, err := operation.execute(&pc, evm.env, contract, mem, stack)
// verifyPool is a build flag. Pool verification makes sure the integrity
// of the integer pool by comparing values to a default value.
if verifyPool {
verifyIntegerPool(evm.intPool)
}
switch {
case err != nil:
return nil, err
case operation.halts:
return res, nil
case !operation.jumps:
pc++
}
}
return nil, nil
}