core/vm: add switches to select evm+ewasm interpreters (ethereum#17687)

Interpreter initialization is left to the PRs implementing them.
Options for external interpreters are passed after a colon in the
`--vm.ewasm` and `--vm.evm` switches.

cmd/geth/main.go

@@ -130,6 +130,8 @@ var (
 		utils.NoCompactionFlag,
 		utils.GpoBlocksFlag,
 		utils.GpoPercentileFlag,
+		utils.EWASMInterpreterFlag,
+		utils.EVMInterpreterFlag,
 		configFileFlag,
 	}
 

cmd/geth/usage.go

@@ -207,6 +207,8 @@ var AppHelpFlagGroups = []flagGroup{
 		Name: "VIRTUAL MACHINE",
 		Flags: []cli.Flag{
 			utils.VMEnableDebugFlag,
+			utils.EVMInterpreterFlag,
+			utils.EWASMInterpreterFlag,
 		},
 	},
 	{

cmd/utils/flags.go

@@ -610,6 +610,17 @@ var (
 		Usage: "InfluxDB `host` tag attached to all measurements",
 		Value: "localhost",
 	}
+
+	EWASMInterpreterFlag = cli.StringFlag{
+		Name:  "vm.ewasm",
+		Usage: "External ewasm configuration (default = built-in interpreter)",
+		Value: "",
+	}
+	EVMInterpreterFlag = cli.StringFlag{
+		Name:  "vm.evm",
+		Usage: "External EVM configuration (default = built-in interpreter)",
+		Value: "",
+	}
 )
 
 // MakeDataDir retrieves the currently requested data directory, terminating
@@ -1184,6 +1195,14 @@ func SetEthConfig(ctx *cli.Context, stack *node.Node, cfg *eth.Config) {
 		cfg.EnablePreimageRecording = ctx.GlobalBool(VMEnableDebugFlag.Name)
 	}
 
+	if ctx.GlobalIsSet(EWASMInterpreterFlag.Name) {
+		cfg.EWASMInterpreter = ctx.GlobalString(EWASMInterpreterFlag.Name)
+	}
+
+	if ctx.GlobalIsSet(EVMInterpreterFlag.Name) {
+		cfg.EVMInterpreter = ctx.GlobalString(EVMInterpreterFlag.Name)
+	}
+
 	// Override any default configs for hard coded networks.
 	switch {
 	case ctx.GlobalBool(TestnetFlag.Name):

core/vm/evm.go

@@ -136,10 +136,28 @@ func NewEVM(ctx Context, statedb StateDB, chainConfig *params.ChainConfig, vmCon
 		vmConfig:     vmConfig,
 		chainConfig:  chainConfig,
 		chainRules:   chainConfig.Rules(ctx.BlockNumber),
-		interpreters: make([]Interpreter, 1),
+		interpreters: make([]Interpreter, 0, 1),
 	}
 
-	evm.interpreters[0] = NewEVMInterpreter(evm, vmConfig)
+	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.
+	evm.interpreters = append(evm.interpreters, NewEVMInterpreter(evm, vmConfig))
 	evm.interpreter = evm.interpreters[0]
 
 	return evm

core/vm/interpreter.go

@@ -39,6 +39,11 @@ type Config struct {
 	// may be left uninitialised and will be set to the default
 	// table.
 	JumpTable [256]operation
+
+	// Type of the EWASM interpreter
+	EWASMInterpreter string
+	// Type of the EVM interpreter
+	EVMInterpreter string
 }
 
 // Interpreter is used to run Ethereum based contracts and will utilise the

eth/backend.go

@@ -149,7 +149,11 @@ func New(ctx *node.ServiceContext, config *Config) (*Ethereum, error) {
 		rawdb.WriteDatabaseVersion(chainDb, core.BlockChainVersion)
 	}
 	var (
-		vmConfig    = vm.Config{EnablePreimageRecording: config.EnablePreimageRecording}
+		vmConfig = vm.Config{
+			EnablePreimageRecording: config.EnablePreimageRecording,
+			EWASMInterpreter:        config.EWASMInterpreter,
+			EVMInterpreter:          config.EVMInterpreter,
+		}
 		cacheConfig = &core.CacheConfig{Disabled: config.NoPruning, TrieNodeLimit: config.TrieCache, TrieTimeLimit: config.TrieTimeout}
 	)
 	eth.blockchain, err = core.NewBlockChain(chainDb, cacheConfig, eth.chainConfig, eth.engine, vmConfig)

eth/config.go

@@ -121,6 +121,11 @@ type Config struct {
 
 	// Miscellaneous options
 	DocRoot string `toml:"-"`
+
+	// Type of the EWASM interpreter ("" for detault)
+	EWASMInterpreter string
+	// Type of the EVM interpreter ("" for default)
+	EVMInterpreter string
 }
 
 type configMarshaling struct {

params/config.go

@@ -84,16 +84,16 @@ var (
 	//
 	// This configuration is intentionally not using keyed fields to force anyone
 	// adding flags to the config to also have to set these fields.
-	AllEthashProtocolChanges = &ChainConfig{big.NewInt(1337), big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), nil, new(EthashConfig), nil}
+	AllEthashProtocolChanges = &ChainConfig{big.NewInt(1337), big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), nil, nil, new(EthashConfig), nil}
 
 	// AllCliqueProtocolChanges contains every protocol change (EIPs) introduced
 	// and accepted by the Ethereum core developers into the Clique consensus.
 	//
 	// This configuration is intentionally not using keyed fields to force anyone
 	// adding flags to the config to also have to set these fields.
-	AllCliqueProtocolChanges = &ChainConfig{big.NewInt(1337), big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), nil, nil, &CliqueConfig{Period: 0, Epoch: 30000}}
+	AllCliqueProtocolChanges = &ChainConfig{big.NewInt(1337), big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), nil, nil, nil, &CliqueConfig{Period: 0, Epoch: 30000}}
 
-	TestChainConfig = &ChainConfig{big.NewInt(1), big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), nil, new(EthashConfig), nil}
+	TestChainConfig = &ChainConfig{big.NewInt(1), big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), nil, nil, new(EthashConfig), nil}
 	TestRules       = TestChainConfig.Rules(new(big.Int))
 )
 
@@ -119,6 +119,7 @@ type ChainConfig struct {
 
 	ByzantiumBlock      *big.Int `json:"byzantiumBlock,omitempty"`      // Byzantium switch block (nil = no fork, 0 = already on byzantium)
 	ConstantinopleBlock *big.Int `json:"constantinopleBlock,omitempty"` // Constantinople switch block (nil = no fork, 0 = already activated)
+	EWASMBlock          *big.Int `json:"ewasmBlock,omitempty"`          // EWASM switch block (nil = no fork, 0 = already activated)
 
 	// Various consensus engines
 	Ethash *EthashConfig `json:"ethash,omitempty"`
@@ -204,6 +205,11 @@ func (c *ChainConfig) IsConstantinople(num *big.Int) bool {
 	return isForked(c.ConstantinopleBlock, num)
 }
 
+// IsEWASM returns whether num represents a block number after the EWASM fork
+func (c *ChainConfig) IsEWASM(num *big.Int) bool {
+	return isForked(c.EWASMBlock, num)
+}
+
 // GasTable returns the gas table corresponding to the current phase (homestead or homestead reprice).
 //
 // The returned GasTable's fields shouldn't, under any circumstances, be changed.
@@ -269,6 +275,9 @@ func (c *ChainConfig) checkCompatible(newcfg *ChainConfig, head *big.Int) *Confi
 	if isForkIncompatible(c.ConstantinopleBlock, newcfg.ConstantinopleBlock, head) {
 		return newCompatError("Constantinople fork block", c.ConstantinopleBlock, newcfg.ConstantinopleBlock)
 	}
+	if isForkIncompatible(c.EWASMBlock, newcfg.EWASMBlock, head) {
+		return newCompatError("ewasm fork block", c.EWASMBlock, newcfg.EWASMBlock)
+	}
 	return nil
 }