go-ethereum/core/vm/interpreter.go

241 lines
8.4 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 (
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/math"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/log"
)
// Config are the configuration options for the Interpreter
type Config struct {
Tracer EVMLogger // Opcode logger
NoBaseFee bool // Forces the EIP-1559 baseFee to 0 (needed for 0 price calls)
EnablePreimageRecording bool // Enables recording of SHA3/keccak preimages
ExtraEips []int // Additional EIPS that are to be enabled
}
// ScopeContext contains the things that are per-call, such as stack and memory,
// but not transients like pc and gas
type ScopeContext struct {
Memory *Memory
Stack *Stack
Contract *Contract
}
// EVMInterpreter represents an EVM interpreter
type EVMInterpreter struct {
evm *EVM
table *JumpTable
hasher crypto.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) *EVMInterpreter {
// If jump table was not initialised we set the default one.
var table *JumpTable
switch {
case evm.chainRules.IsShanghai:
table = &shanghaiInstructionSet
case evm.chainRules.IsMerge:
table = &mergeInstructionSet
case evm.chainRules.IsLondon:
table = &londonInstructionSet
case evm.chainRules.IsBerlin:
table = &berlinInstructionSet
case evm.chainRules.IsIstanbul:
table = &istanbulInstructionSet
case evm.chainRules.IsConstantinople:
table = &constantinopleInstructionSet
case evm.chainRules.IsByzantium:
table = &byzantiumInstructionSet
case evm.chainRules.IsEIP158:
table = &spuriousDragonInstructionSet
case evm.chainRules.IsEIP150:
table = &tangerineWhistleInstructionSet
case evm.chainRules.IsHomestead:
table = &homesteadInstructionSet
default:
table = &frontierInstructionSet
}
var extraEips []int
if len(evm.Config.ExtraEips) > 0 {
// Deep-copy jumptable to prevent modification of opcodes in other tables
table = copyJumpTable(table)
}
for _, eip := range evm.Config.ExtraEips {
if err := EnableEIP(eip, table); err != nil {
// Disable it, so caller can check if it's activated or not
log.Error("EIP activation failed", "eip", eip, "error", err)
} else {
extraEips = append(extraEips, eip)
}
}
evm.Config.ExtraEips = extraEips
return &EVMInterpreter{evm: evm, table: table}
}
// 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) {
// Increment the call depth which is restricted to 1024
in.evm.depth++
defer func() { in.evm.depth-- }()
// Make sure the readOnly is only set if we aren't in readOnly yet.
// This also makes sure that the readOnly flag isn't removed for child calls.
if readOnly && !in.readOnly {
in.readOnly = true
defer func() { in.readOnly = false }()
}
// Reset the previous call's return data. It's unimportant to preserve the old buffer
// as every returning call will return new data anyway.
in.returnData = nil
// Don't bother with the execution if there's no code.
if len(contract.Code) == 0 {
return nil, nil
}
var (
op OpCode // current opcode
mem = NewMemory() // bound memory
stack = newstack() // local stack
callContext = &ScopeContext{
Memory: mem,
Stack: stack,
Contract: contract,
}
// 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
// copies used by tracer
pcCopy uint64 // needed for the deferred EVMLogger
gasCopy uint64 // for EVMLogger to log gas remaining before execution
logged bool // deferred EVMLogger should ignore already logged steps
res []byte // result of the opcode execution function
debug = in.evm.Config.Tracer != nil
)
// Don't move this deferred function, it's placed before the capturestate-deferred method,
// so that it get's executed _after_: the capturestate needs the stacks before
// they are returned to the pools
defer func() {
returnStack(stack)
}()
contract.Input = input
if debug {
defer func() {
if err != nil {
if !logged {
in.evm.Config.Tracer.CaptureState(pcCopy, op, gasCopy, cost, callContext, in.returnData, in.evm.depth, err)
} else {
in.evm.Config.Tracer.CaptureFault(pcCopy, op, gasCopy, cost, callContext, in.evm.depth, err)
}
}
}()
}
// 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 done flag is set by the
// parent context.
for {
if debug {
// Capture pre-execution values for tracing.
logged, pcCopy, gasCopy = false, pc, contract.Gas
}
// Get the operation from the jump table and validate the stack to ensure there are
// enough stack items available to perform the operation.
op = contract.GetOp(pc)
operation := in.table[op]
cost = operation.constantGas // For tracing
// Validate stack
if sLen := stack.len(); sLen < operation.minStack {
return nil, &ErrStackUnderflow{stackLen: sLen, required: operation.minStack}
} else if sLen > operation.maxStack {
return nil, &ErrStackOverflow{stackLen: sLen, limit: operation.maxStack}
}
if !contract.UseGas(cost) {
return nil, ErrOutOfGas
}
if operation.dynamicGas != nil {
// All ops with a dynamic memory usage also has a dynamic gas cost.
var memorySize uint64
// calculate the new memory size and expand the memory to fit
// the operation
// Memory check needs to be done prior to evaluating the dynamic gas portion,
// to detect calculation overflows
if operation.memorySize != nil {
memSize, overflow := 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
}
}
// Consume the gas and return an error if not enough gas is available.
// cost is explicitly set so that the capture state defer method can get the proper cost
var dynamicCost uint64
dynamicCost, err = operation.dynamicGas(in.evm, contract, stack, mem, memorySize)
cost += dynamicCost // for tracing
if err != nil || !contract.UseGas(dynamicCost) {
return nil, ErrOutOfGas
}
// Do tracing before memory expansion
if debug {
in.evm.Config.Tracer.CaptureState(pc, op, gasCopy, cost, callContext, in.returnData, in.evm.depth, err)
logged = true
}
if memorySize > 0 {
mem.Resize(memorySize)
}
} else if debug {
in.evm.Config.Tracer.CaptureState(pc, op, gasCopy, cost, callContext, in.returnData, in.evm.depth, err)
logged = true
}
// execute the operation
res, err = operation.execute(&pc, in, callContext)
if err != nil {
break
}
pc++
}
if err == errStopToken {
err = nil // clear stop token error
}
return res, err
}