core/vm: Add EVMC support

Author: chfast

core/vm/evm.go

@@ -140,24 +140,21 @@ func NewEVM(ctx Context, statedb StateDB, chainConfig *params.ChainConfig, vmCon
 	}
 
 	if chainConfig.IsEWASM(ctx.BlockNumber) {
-		// to be implemented by EVM-C and Wagon PRs.
-		// if vmConfig.EWASMInterpreter != "" {
-		//  extIntOpts := strings.Split(vmConfig.EWASMInterpreter, ":")
-		//  path := extIntOpts[0]
-		//  options := []string{}
-		//  if len(extIntOpts) > 1 {
-		//    options = extIntOpts[1..]
-		//  }
-		//  evm.interpreters = append(evm.interpreters, NewEVMVCInterpreter(evm, vmConfig, options))
-		// } else {
-		// 	evm.interpreters = append(evm.interpreters, NewEWASMInterpreter(evm, vmConfig))
-		// }
-		panic("No supported ewasm interpreter yet.")
-	}
-
-	// vmConfig.EVMInterpreter will be used by EVM-C, it won't be checked here
-	// as we always want to have the built-in EVM as the failover option.
+		if vmConfig.EWASMInterpreter != "" {
+			evm.interpreters = append(evm.interpreters, NewEVMC(vmConfig.EWASMInterpreter, evm))
+		} else {
+			panic("The default ewasm interpreter not supported yet.")
+		}
+	}
+
+	if vmConfig.EVMInterpreter != "" {
+		// Create custom EVM.
+		evm.interpreters = append(evm.interpreters, NewEVMC(vmConfig.EVMInterpreter, evm))
+	}
+
+	// Keep the built-in EVM as the failover option.
 	evm.interpreters = append(evm.interpreters, NewEVMInterpreter(evm, vmConfig))
+
 	evm.interpreter = evm.interpreters[0]
 
 	return evm

core/vm/evmc.go

@@ -0,0 +1,325 @@
+// Copyright 2018 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 (
+	"bytes"
+	"fmt"
+	"math/big"
+	"strings"
+	"sync"
+
+	"github.com/ethereum/evmc/bindings/go/evmc"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/params"
+)
+
+type EVMC struct {
+	instance *evmc.Instance
+	env      *EVM
+	readOnly bool // TODO: The readOnly flag should not be here.
+}
+
+var (
+	createMu     sync.Mutex
+	evmcConfig   string // The configuration the instance was created with.
+	evmcInstance *evmc.Instance
+)
+
+func createVM(config string) *evmc.Instance {
+	createMu.Lock()
+	defer createMu.Unlock()
+
+	if evmcInstance == nil {
+		options := strings.Split(config, ",")
+		path := options[0]
+
+		if path == "" {
+			panic("EVMC VM path not provided, set --vm.(evm|ewasm)=/path/to/vm")
+		}
+
+		var err error
+		evmcInstance, err = evmc.Load(path)
+		if err != nil {
+			panic(err.Error())
+		}
+		log.Info("EVMC VM loaded", "name", evmcInstance.Name(), "version", evmcInstance.Version(), "path", path)
+
+		for _, option := range options[1:] {
+			if idx := strings.Index(option, "="); idx >= 0 {
+				name := option[:idx]
+				value := option[idx+1:]
+				err := evmcInstance.SetOption(name, value)
+				if err == nil {
+					log.Info("EVMC VM option set", "name", name, "value", value)
+				} else {
+					log.Warn("EVMC VM option setting failed", "name", name, "error", err)
+				}
+			}
+		}
+
+		evm1Cap := evmcInstance.HasCapability(evmc.CapabilityEVM1)
+		ewasmCap := evmcInstance.HasCapability(evmc.CapabilityEWASM)
+		log.Info("EVMC VM capabilities", "evm1", evm1Cap, "ewasm", ewasmCap)
+
+		evmcConfig = config // Remember the config.
+	} else if evmcConfig != config {
+		log.Error("New EVMC VM requested", "newconfig", config, "oldconfig", evmcConfig)
+	}
+	return evmcInstance
+}
+
+func NewEVMC(options string, env *EVM) *EVMC {
+	return &EVMC{createVM(options), env, false}
+}
+
+// Implements evmc.HostContext interface.
+type HostContext struct {
+	env      *EVM
+	contract *Contract
+}
+
+func (host *HostContext) AccountExists(addr common.Address) bool {
+	env := host.env
+	eip158 := env.ChainConfig().IsEIP158(env.BlockNumber)
+	if eip158 {
+		if !env.StateDB.Empty(addr) {
+			return true
+		}
+	} else if env.StateDB.Exist(addr) {
+		return true
+	}
+	return false
+}
+
+func (host *HostContext) GetStorage(addr common.Address, key common.Hash) common.Hash {
+	env := host.env
+	return env.StateDB.GetState(addr, key)
+}
+
+func (host *HostContext) SetStorage(addr common.Address, key common.Hash, value common.Hash) (status evmc.StorageStatus) {
+	env := host.env
+
+	oldValue := env.StateDB.GetState(addr, key)
+	if oldValue == value {
+		return evmc.StorageUnchanged
+	}
+
+	env.StateDB.SetState(addr, key, value)
+
+	zero := common.Hash{}
+	status = evmc.StorageModified
+	if oldValue == zero {
+		return evmc.StorageAdded
+	} else if value == zero {
+		env.StateDB.AddRefund(params.SstoreRefundGas)
+		return evmc.StorageDeleted
+	}
+	return evmc.StorageModified
+}
+
+func (host *HostContext) GetBalance(addr common.Address) common.Hash {
+	env := host.env
+	balance := env.StateDB.GetBalance(addr)
+	return common.BigToHash(balance)
+}
+
+func (host *HostContext) GetCodeSize(addr common.Address) int {
+	env := host.env
+	return env.StateDB.GetCodeSize(addr)
+}
+
+func (host *HostContext) GetCodeHash(addr common.Address) common.Hash {
+	env := host.env
+	return env.StateDB.GetCodeHash(addr)
+}
+
+func (host *HostContext) GetCode(addr common.Address) []byte {
+	env := host.env
+	return env.StateDB.GetCode(addr)
+}
+
+func (host *HostContext) Selfdestruct(addr common.Address, beneficiary common.Address) {
+	env := host.env
+	db := env.StateDB
+	if !db.HasSuicided(addr) {
+		db.AddRefund(params.SuicideRefundGas)
+	}
+	balance := db.GetBalance(addr)
+	db.AddBalance(beneficiary, balance)
+	db.Suicide(addr)
+}
+
+func (host *HostContext) GetTxContext() (gasPrice common.Hash, origin common.Address, coinbase common.Address,
+	number int64, timestamp int64, gasLimit int64, difficulty common.Hash) {
+
+	env := host.env
+	gasPrice = common.BigToHash(env.GasPrice)
+	origin = env.Origin
+	coinbase = env.Coinbase
+	number = env.BlockNumber.Int64()
+	timestamp = env.Time.Int64()
+	gasLimit = int64(env.GasLimit)
+	difficulty = common.BigToHash(env.Difficulty)
+
+	return gasPrice, origin, coinbase, number, timestamp, gasLimit, difficulty
+}
+
+func (host *HostContext) GetBlockHash(number int64) common.Hash {
+	env := host.env
+	b := env.BlockNumber.Int64()
+	if number >= (b-256) && number < b {
+		return env.GetHash(uint64(number))
+	}
+	return common.Hash{}
+}
+
+func (host *HostContext) EmitLog(addr common.Address, topics []common.Hash, data []byte) {
+	env := host.env
+	env.StateDB.AddLog(&types.Log{
+		Address:     addr,
+		Topics:      topics,
+		Data:        data,
+		BlockNumber: env.BlockNumber.Uint64(),
+	})
+}
+
+func (host *HostContext) Call(kind evmc.CallKind,
+	destination common.Address, sender common.Address, value *big.Int, input []byte, gas int64, depth int,
+	static bool) (output []byte, gasLeft int64, createAddr common.Address, err error) {
+
+	env := host.env
+
+	gasU := uint64(gas)
+	var gasLeftU uint64
+
+	switch kind {
+	case evmc.Call:
+		if static {
+			output, gasLeftU, err = env.StaticCall(host.contract, destination, input, gasU)
+		} else {
+			output, gasLeftU, err = env.Call(host.contract, destination, input, gasU, value)
+		}
+	case evmc.DelegateCall:
+		output, gasLeftU, err = env.DelegateCall(host.contract, destination, input, gasU)
+	case evmc.CallCode:
+		output, gasLeftU, err = env.CallCode(host.contract, destination, input, gasU, value)
+	case evmc.Create:
+		var createOutput []byte
+		createOutput, createAddr, gasLeftU, err = env.Create(host.contract, input, gasU, value)
+		isHomestead := env.ChainConfig().IsHomestead(env.BlockNumber)
+		if !isHomestead && err == ErrCodeStoreOutOfGas {
+			err = nil
+		}
+		if err == errExecutionReverted {
+			// Assign return buffer from REVERT.
+			// TODO: Bad API design: return data buffer and the code is returned in the same place. In worst case
+			//       the code is returned also when there is not enough funds to deploy the code.
+			output = createOutput
+		}
+	}
+
+	// Map errors.
+	if err == errExecutionReverted {
+		err = evmc.Revert
+	} else if err != nil {
+		err = evmc.Failure
+	}
+
+	gasLeft = int64(gasLeftU)
+	return output, gasLeft, createAddr, err
+}
+
+func getRevision(env *EVM) evmc.Revision {
+	n := env.BlockNumber
+	conf := env.ChainConfig()
+	if conf.IsConstantinople(n) {
+		return evmc.Constantinople
+	}
+	if conf.IsByzantium(n) {
+		return evmc.Byzantium
+	}
+	if conf.IsEIP158(n) {
+		return evmc.SpuriousDragon
+	}
+	if conf.IsEIP150(n) {
+		return evmc.TangerineWhistle
+	}
+	if conf.IsHomestead(n) {
+		return evmc.Homestead
+	}
+	return evmc.Frontier
+}
+
+func (evm *EVMC) Run(contract *Contract, input []byte, readOnly bool) (ret []byte, err error) {
+	evm.env.depth++
+	defer func() { evm.env.depth-- }()
+
+	// Don't bother with the execution if there's no code.
+	if len(contract.Code) == 0 {
+		return nil, nil
+	}
+
+	kind := evmc.Call
+	if evm.env.StateDB.GetCodeSize(contract.Address()) == 0 {
+		// Guess if this is a CREATE.
+		kind = evmc.Create
+	}
+
+	// Make sure the readOnly is only set if we aren't in readOnly yet.
+	// This makes also sure that the readOnly flag isn't removed for child calls.
+	if readOnly && !evm.readOnly {
+		evm.readOnly = true
+		defer func() { evm.readOnly = false }()
+	}
+
+	output, gasLeft, err := evm.instance.Execute(
+		&HostContext{evm.env, contract},
+		getRevision(evm.env),
+		kind,
+		evm.readOnly,
+		evm.env.depth-1,
+		int64(contract.Gas),
+		contract.Address(),
+		contract.Caller(),
+		input,
+		common.BigToHash(contract.value),
+		contract.Code,
+		common.Hash{})
+
+	contract.Gas = uint64(gasLeft)
+
+	if err == evmc.Revert {
+		err = errExecutionReverted
+	} else if evmcError, ok := err.(evmc.Error); ok && evmcError.IsInternalError() {
+		panic(fmt.Sprintf("EVMC VM internal error: %s", evmcError.Error()))
+	}
+
+	return output, err
+}
+
+func (evm *EVMC) CanRun(code []byte) bool {
+	cap := evmc.CapabilityEVM1
+	wasmPreamble := []byte("\x00asm\x01\x00\x00\x00")
+	if bytes.HasPrefix(code, wasmPreamble) {
+		cap = evmc.CapabilityEWASM
+	}
+	// FIXME: Optimize. Access capabilities once.
+	return evm.instance.HasCapability(cap)
+}