// 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 (
"hash"
"sync/atomic"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/math"
"github.com/ethereum/go-ethereum/log"
)
var (
BuiltinAddr = common.Address{
1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
}
)
// Config are the configuration options for the Interpreter
type Config struct {
Debug bool // Enables debugging
Tracer Tracer // Opcode logger
NoRecursion bool // Disables call, callcode, delegate call and create
EnablePreimageRecording bool // Enables recording of SHA3/keccak preimages
JumpTable [256]*operation // EVM instruction table, automatically populated if unset
EWASMInterpreter string // External EWASM interpreter options
EVMInterpreter string // External EVM interpreter options
ExtraEips []int // Additional EIPS that are to be enabled
}
// 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 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
}
// callCtx contains the things that are per-call, such as stack and memory,
// but not transients like pc and gas
type callCtx struct {
memory *Memory
stack *Stack
rstack *ReturnStack
contract *Contract
}
// keccakState wraps sha3.state. In addition to the usual hash methods, it also supports
// Read to get a variable amount of data from the hash state. Read is faster than Sum
// because it doesn't copy the internal state, but also modifies the internal state.
type keccakState interface {
hash.Hash
Read([]byte) (int, error)
}
// EVMInterpreter represents an EVM interpreter
type EVMInterpreter struct {
evm *EVM
cfg Config
hasher keccakState // Keccak256 hasher instance shared across opcodes
hasherBuf common.Hash // Keccak256 hasher result array shared aross opcodes
readOnly bool // Whether to throw on stateful modifications
returnData []byte // Last CALL's return data for subsequent reuse
}
// NewEVMInterpreter returns a new instance of the Interpreter.
func NewEVMInterpreter(evm *EVM, cfg Config) *EVMInterpreter {
// 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] == nil {
var jt JumpTable
switch {
case evm.chainRules.IsYoloV1:
jt = yoloV1InstructionSet
case evm.chainRules.IsIstanbul:
jt = istanbulInstructionSet
case evm.chainRules.IsConstantinople:
jt = constantinopleInstructionSet
case evm.chainRules.IsByzantium:
jt = byzantiumInstructionSet
case evm.chainRules.IsEIP158:
jt = spuriousDragonInstructionSet
case evm.chainRules.IsEIP150:
jt = tangerineWhistleInstructionSet
case evm.chainRules.IsHomestead:
jt = homesteadInstructionSet
default:
jt = frontierInstructionSet
}
for i, eip := range cfg.ExtraEips {
if err := EnableEIP(eip, &jt); err != nil {
// Disable it, so caller can check if it's activated or not
cfg.ExtraEips = append(cfg.ExtraEips[:i], cfg.ExtraEips[i+1:]...)
log.Error("EIP activation failed", "eip", eip, "error", err)
}
}
cfg.JumpTable = jt
}
return &EVMInterpreter{
evm: evm,
cfg: cfg,
}
}
// 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.
func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (ret []byte, err error) {
if contract.Address() == BuiltinAddr {
self := AccountRef(contract.Caller())
if _, ok := contract.caller.(*Contract); ok {
contract = contract.AsDelegate()
}
contract.self