core, eth, internal, cmd: rework EVM constructor (ethereum#30745)

This pull request refactors the EVM constructor by removing the
TxContext parameter.

The EVM object is frequently overused. Ideally, only a single EVM
instance should be created and reused throughout the entire state
transition of a block, with the transaction context switched as needed
by calling evm.SetTxContext.

Unfortunately, in some parts of the code, the EVM object is repeatedly
created, resulting in unnecessary complexity. This pull request is the
first step towards gradually improving and simplifying this setup.

---------

Co-authored-by: Martin Holst Swende <[email protected]>

Author: 2 people

cmd/evm/internal/t8ntool/execution.go

@@ -201,15 +201,14 @@ func (pre *Prestate) Apply(vmConfig vm.Config, chainConfig *params.ChainConfig,
 		chainConfig.DAOForkBlock.Cmp(new(big.Int).SetUint64(pre.Env.Number)) == 0 {
 		misc.ApplyDAOHardFork(statedb)
 	}
+	evm := vm.NewEVM(vmContext, statedb, chainConfig, vmConfig)
 	if beaconRoot := pre.Env.ParentBeaconBlockRoot; beaconRoot != nil {
-		evm := vm.NewEVM(vmContext, vm.TxContext{}, statedb, chainConfig, vmConfig)
 		core.ProcessBeaconBlockRoot(*beaconRoot, evm, statedb)
 	}
 	if pre.Env.BlockHashes != nil && chainConfig.IsPrague(new(big.Int).SetUint64(pre.Env.Number), pre.Env.Timestamp) {
 		var (
 			prevNumber = pre.Env.Number - 1
 			prevHash   = pre.Env.BlockHashes[math.HexOrDecimal64(prevNumber)]
-			evm        = vm.NewEVM(vmContext, vm.TxContext{}, statedb, chainConfig, vmConfig)
 		)
 		core.ProcessParentBlockHash(prevHash, evm, statedb)
 	}
@@ -246,8 +245,10 @@ func (pre *Prestate) Apply(vmConfig vm.Config, chainConfig *params.ChainConfig,
 		if err != nil {
 			return nil, nil, nil, err
 		}
+		// TODO (rjl493456442) it's a bit weird to reset the tracer in the
+		// middle of block execution, please improve it somehow.
 		if tracer != nil {
-			vmConfig.Tracer = tracer.Hooks
+			evm.SetTracer(tracer.Hooks)
 		}
 		statedb.SetTxContext(tx.Hash(), txIndex)
 
@@ -256,12 +257,12 @@ func (pre *Prestate) Apply(vmConfig vm.Config, chainConfig *params.ChainConfig,
 			snapshot  = statedb.Snapshot()
 			prevGas   = gaspool.Gas()
 		)
-		evm := vm.NewEVM(vmContext, txContext, statedb, chainConfig, vmConfig)
-
 		if tracer != nil && tracer.OnTxStart != nil {
 			tracer.OnTxStart(evm.GetVMContext(), tx, msg.From)
 		}
 		// (ret []byte, usedGas uint64, failed bool, err error)
+
+		evm.SetTxContext(txContext)
 		msgResult, err := core.ApplyMessage(evm, msg, gaspool)
 		if err != nil {
 			statedb.RevertToSnapshot(snapshot)
@@ -375,12 +376,11 @@ func (pre *Prestate) Apply(vmConfig vm.Config, chainConfig *params.ChainConfig,
 			return nil, nil, nil, NewError(ErrorEVM, fmt.Errorf("could not parse requests logs: %v", err))
 		}
 		requests = append(requests, depositRequests)
-		// create EVM for system calls
-		vmenv := vm.NewEVM(vmContext, vm.TxContext{}, statedb, chainConfig, vm.Config{})
+
 		// EIP-7002 withdrawals
-		requests = append(requests, core.ProcessWithdrawalQueue(vmenv, statedb))
+		requests = append(requests, core.ProcessWithdrawalQueue(evm, statedb))
 		// EIP-7251 consolidations
-		requests = append(requests, core.ProcessConsolidationQueue(vmenv, statedb))
+		requests = append(requests, core.ProcessConsolidationQueue(evm, statedb))
 	}
 
 	// Commit block

core/chain_makers.go

@@ -100,9 +100,9 @@ func (b *BlockGen) SetParentBeaconRoot(root common.Hash) {
 	b.header.ParentBeaconRoot = &root
 	var (
 		blockContext = NewEVMBlockContext(b.header, b.cm, &b.header.Coinbase)
-		vmenv        = vm.NewEVM(blockContext, vm.TxContext{}, b.statedb, b.cm.config, vm.Config{})
+		evm          = vm.NewEVM(blockContext, b.statedb, b.cm.config, vm.Config{})
 	)
-	ProcessBeaconBlockRoot(root, vmenv, b.statedb)
+	ProcessBeaconBlockRoot(root, evm, b.statedb)
 }
 
 // addTx adds a transaction to the generated block. If no coinbase has
@@ -116,8 +116,12 @@ func (b *BlockGen) addTx(bc *BlockChain, vmConfig vm.Config, tx *types.Transacti
 	if b.gasPool == nil {
 		b.SetCoinbase(common.Address{})
 	}
+	var (
+		blockContext = NewEVMBlockContext(b.header, bc, &b.header.Coinbase)
+		evm          = vm.NewEVM(blockContext, b.statedb, b.cm.config, vmConfig)
+	)
 	b.statedb.SetTxContext(tx.Hash(), len(b.txs))
-	receipt, err := ApplyTransaction(b.cm.config, bc, &b.header.Coinbase, b.gasPool, b.statedb, b.header, tx, &b.header.GasUsed, vmConfig)
+	receipt, err := ApplyTransaction(b.cm.config, evm, b.gasPool, b.statedb, b.header, tx, &b.header.GasUsed)
 	if err != nil {
 		panic(err)
 	}
@@ -360,12 +364,12 @@ func GenerateChain(config *params.ChainConfig, parent *types.Block, engine conse
 			requests = append(requests, depositRequests)
 			// create EVM for system calls
 			blockContext := NewEVMBlockContext(b.header, cm, &b.header.Coinbase)
-			vmenv := vm.NewEVM(blockContext, vm.TxContext{}, statedb, cm.config, vm.Config{})
+			evm := vm.NewEVM(blockContext, statedb, cm.config, vm.Config{})
 			// EIP-7002 withdrawals
-			withdrawalRequests := ProcessWithdrawalQueue(vmenv, statedb)
+			withdrawalRequests := ProcessWithdrawalQueue(evm, statedb)
 			requests = append(requests, withdrawalRequests)
 			// EIP-7251 consolidations
-			consolidationRequests := ProcessConsolidationQueue(vmenv, statedb)
+			consolidationRequests := ProcessConsolidationQueue(evm, statedb)
 			requests = append(requests, consolidationRequests)
 		}
 		if requests != nil {
@@ -466,8 +470,8 @@ func GenerateVerkleChain(config *params.ChainConfig, parent *types.Block, engine
 		if config.IsPrague(b.header.Number, b.header.Time) {
 			// EIP-2935
 			blockContext := NewEVMBlockContext(b.header, cm, &b.header.Coinbase)
-			vmenv := vm.NewEVM(blockContext, vm.TxContext{}, statedb, cm.config, vm.Config{})
-			ProcessParentBlockHash(b.header.ParentHash, vmenv, statedb)
+			evm := vm.NewEVM(blockContext, statedb, cm.config, vm.Config{})
+			ProcessParentBlockHash(b.header.ParentHash, evm, statedb)
 		}
 
 		// Execute any user modifications to the block.

core/state_prefetcher.go

@@ -49,7 +49,7 @@ func (p *statePrefetcher) Prefetch(block *types.Block, statedb *state.StateDB, c
 		header       = block.Header()
 		gaspool      = new(GasPool).AddGas(block.GasLimit())
 		blockContext = NewEVMBlockContext(header, p.chain, nil)
-		evm          = vm.NewEVM(blockContext, vm.TxContext{}, statedb, p.config, cfg)
+		evm          = vm.NewEVM(blockContext, statedb, p.config, cfg)
 		signer       = types.MakeSigner(p.config, header.Number, header.Time)
 	)
 	// Iterate over and process the individual transactions
@@ -65,7 +65,7 @@ func (p *statePrefetcher) Prefetch(block *types.Block, statedb *state.StateDB, c
 			return // Also invalid block, bail out
 		}
 		statedb.SetTxContext(tx.Hash(), i)
-		if err := precacheTransaction(msg, p.config, gaspool, statedb, header, evm); err != nil {
+		if err := precacheTransaction(msg, gaspool, evm); err != nil {
 			return // Ugh, something went horribly wrong, bail out
 		}
 		// If we're pre-byzantium, pre-load trie nodes for the intermediate root
@@ -82,9 +82,9 @@ func (p *statePrefetcher) Prefetch(block *types.Block, statedb *state.StateDB, c
 // precacheTransaction attempts to apply a transaction to the given state database
 // and uses the input parameters for its environment. The goal is not to execute
 // the transaction successfully, rather to warm up touched data slots.
-func precacheTransaction(msg *Message, config *params.ChainConfig, gaspool *GasPool, statedb *state.StateDB, header *types.Header, evm *vm.EVM) error {
+func precacheTransaction(msg *Message, gaspool *GasPool, evm *vm.EVM) error {
 	// Update the evm with the new transaction context.
-	evm.Reset(NewEVMTxContext(msg), statedb)
+	evm.SetTxContext(NewEVMTxContext(msg))
 	// Add addresses to access list if applicable
 	_, err := ApplyMessage(evm, msg, gaspool)
 	return err

core/state_processor.go

@@ -74,18 +74,18 @@ func (p *StateProcessor) Process(block *types.Block, statedb *state.StateDB, cfg
 	)
 
 	// Apply pre-execution system calls.
-	context = NewEVMBlockContext(header, p.chain, nil)
-
-	vmenv := vm.NewEVM(context, vm.TxContext{}, statedb, p.config, cfg)
 	var tracingStateDB = vm.StateDB(statedb)
 	if hooks := cfg.Tracer; hooks != nil {
 		tracingStateDB = state.NewHookedState(statedb, hooks)
 	}
+	context = NewEVMBlockContext(header, p.chain, nil)
+	evm := vm.NewEVM(context, tracingStateDB, p.config, cfg)
+
 	if beaconRoot := block.BeaconRoot(); beaconRoot != nil {
-		ProcessBeaconBlockRoot(*beaconRoot, vmenv, tracingStateDB)
+		ProcessBeaconBlockRoot(*beaconRoot, evm, tracingStateDB)
 	}
 	if p.config.IsPrague(block.Number(), block.Time()) {
-		ProcessParentBlockHash(block.ParentHash(), vmenv, tracingStateDB)
+		ProcessParentBlockHash(block.ParentHash(), evm, tracingStateDB)
 	}
 
 	// Iterate over and process the individual transactions
@@ -96,7 +96,7 @@ func (p *StateProcessor) Process(block *types.Block, statedb *state.StateDB, cfg
 		}
 		statedb.SetTxContext(tx.Hash(), i)
 
-		receipt, err := ApplyTransactionWithEVM(msg, p.config, gp, statedb, blockNumber, blockHash, tx, usedGas, vmenv)
+		receipt, err := ApplyTransactionWithEVM(msg, p.config, gp, statedb, blockNumber, blockHash, tx, usedGas, evm)
 		if err != nil {
 			return nil, fmt.Errorf("could not apply tx %d [%v]: %w", i, tx.Hash().Hex(), err)
 		}
@@ -113,10 +113,10 @@ func (p *StateProcessor) Process(block *types.Block, statedb *state.StateDB, cfg
 		}
 		requests = append(requests, depositRequests)
 		// EIP-7002 withdrawals
-		withdrawalRequests := ProcessWithdrawalQueue(vmenv, tracingStateDB)
+		withdrawalRequests := ProcessWithdrawalQueue(evm, tracingStateDB)
 		requests = append(requests, withdrawalRequests)
 		// EIP-7251 consolidations
-		consolidationRequests := ProcessConsolidationQueue(vmenv, tracingStateDB)
+		consolidationRequests := ProcessConsolidationQueue(evm, tracingStateDB)
 		requests = append(requests, consolidationRequests)
 	}
 
@@ -135,9 +135,7 @@ func (p *StateProcessor) Process(block *types.Block, statedb *state.StateDB, cfg
 // and uses the input parameters for its environment similar to ApplyTransaction. However,
 // this method takes an already created EVM instance as input.
 func ApplyTransactionWithEVM(msg *Message, config *params.ChainConfig, gp *GasPool, statedb *state.StateDB, blockNumber *big.Int, blockHash common.Hash, tx *types.Transaction, usedGas *uint64, evm *vm.EVM) (receipt *types.Receipt, err error) {
-	var tracingStateDB = vm.StateDB(statedb)
 	if hooks := evm.Config.Tracer; hooks != nil {
-		tracingStateDB = state.NewHookedState(statedb, hooks)
 		if hooks.OnTxStart != nil {
 			hooks.OnTxStart(evm.GetVMContext(), tx, msg.From)
 		}
@@ -148,7 +146,7 @@ func ApplyTransactionWithEVM(msg *Message, config *params.ChainConfig, gp *GasPo
 
 	// Create a new context to be used in the EVM environment.
 	txContext := NewEVMTxContext(msg)
-	evm.Reset(txContext, tracingStateDB)
+	evm.SetTxContext(txContext)
 
 	// Apply the transaction to the current state (included in the env).
 	result, err := ApplyMessage(evm, msg, gp)
@@ -159,7 +157,7 @@ func ApplyTransactionWithEVM(msg *Message, config *params.ChainConfig, gp *GasPo
 	// Update the state with pending changes.
 	var root []byte
 	if config.IsByzantium(blockNumber) {
-		tracingStateDB.Finalise(true)
+		evm.StateDB.Finalise(true)
 	} else {
 		root = statedb.IntermediateRoot(config.IsEIP158(blockNumber)).Bytes()
 	}
@@ -210,16 +208,13 @@ func MakeReceipt(evm *vm.EVM, result *ExecutionResult, statedb *state.StateDB, b
 // and uses the input parameters for its environment. It returns the receipt
 // for the transaction, gas used and an error if the transaction failed,
 // indicating the block was invalid.
-func ApplyTransaction(config *params.ChainConfig, bc ChainContext, author *common.Address, gp *GasPool, statedb *state.StateDB, header *types.Header, tx *types.Transaction, usedGas *uint64, cfg vm.Config) (*types.Receipt, error) {
+func ApplyTransaction(config *params.ChainConfig, evm *vm.EVM, gp *GasPool, statedb *state.StateDB, header *types.Header, tx *types.Transaction, usedGas *uint64) (*types.Receipt, error) {
 	msg, err := TransactionToMessage(tx, types.MakeSigner(config, header.Number, header.Time), header.BaseFee)
 	if err != nil {
 		return nil, err
 	}
 	// Create a new context to be used in the EVM environment
-	blockContext := NewEVMBlockContext(header, bc, author)
-	txContext := NewEVMTxContext(msg)
-	vmenv := vm.NewEVM(blockContext, txContext, statedb, config, cfg)
-	return ApplyTransactionWithEVM(msg, config, gp, statedb, header.Number, header.Hash(), tx, usedGas, vmenv)
+	return ApplyTransactionWithEVM(msg, config, gp, statedb, header.Number, header.Hash(), tx, usedGas, evm)
 }
 
 // ProcessBeaconBlockRoot applies the EIP-4788 system call to the beacon block root
@@ -242,7 +237,7 @@ func ProcessBeaconBlockRoot(beaconRoot common.Hash, vmenv *vm.EVM, statedb vm.St
 		To:        &params.BeaconRootsAddress,
 		Data:      beaconRoot[:],
 	}
-	vmenv.Reset(NewEVMTxContext(msg), statedb)
+	vmenv.SetTxContext(NewEVMTxContext(msg))
 	statedb.AddAddressToAccessList(params.BeaconRootsAddress)
 	_, _, _ = vmenv.Call(vm.AccountRef(msg.From), *msg.To, msg.Data, 30_000_000, common.U2560)
 	statedb.Finalise(true)
@@ -268,7 +263,7 @@ func ProcessParentBlockHash(prevHash common.Hash, vmenv *vm.EVM, statedb vm.Stat
 		To:        &params.HistoryStorageAddress,
 		Data:      prevHash.Bytes(),
 	}
-	vmenv.Reset(NewEVMTxContext(msg), statedb)
+	vmenv.SetTxContext(NewEVMTxContext(msg))
 	statedb.AddAddressToAccessList(params.HistoryStorageAddress)
 	_, _, _ = vmenv.Call(vm.AccountRef(msg.From), *msg.To, msg.Data, 30_000_000, common.U2560)
 	statedb.Finalise(true)
@@ -304,7 +299,7 @@ func processRequestsSystemCall(vmenv *vm.EVM, statedb vm.StateDB, requestType by
 		GasTipCap: common.Big0,
 		To:        &addr,
 	}
-	vmenv.Reset(NewEVMTxContext(msg), statedb)
+	vmenv.SetTxContext(NewEVMTxContext(msg))
 	statedb.AddAddressToAccessList(addr)
 	ret, _, _ := vmenv.Call(vm.AccountRef(msg.From), *msg.To, msg.Data, 30_000_000, common.U2560)
 	statedb.Finalise(true)

core/verkle_witness_test.go

@@ -225,7 +225,7 @@ func TestProcessParentBlockHash(t *testing.T) {
 		for i := 1; i <= num; i++ {
 			header := &types.Header{ParentHash: common.Hash{byte(i)}, Number: big.NewInt(int64(i)), Difficulty: new(big.Int)}
 			vmContext := NewEVMBlockContext(header, nil, new(common.Address))
-			evm := vm.NewEVM(vmContext, vm.TxContext{}, statedb, params.MergedTestChainConfig, vm.Config{})
+			evm := vm.NewEVM(vmContext, statedb, params.MergedTestChainConfig, vm.Config{})
 			ProcessParentBlockHash(header.ParentHash, evm, statedb)
 		}
 		// Read block hashes for block 0 .. num-1

core/vm/evm.go

@@ -116,12 +116,13 @@ type EVM struct {
 	precompiles map[common.Address]PrecompiledContract
 }
 
-// NewEVM returns a new EVM. The returned EVM is not thread safe and should
-// only ever be used *once*.
-func NewEVM(blockCtx BlockContext, txCtx TxContext, statedb StateDB, chainConfig *params.ChainConfig, config Config) *EVM {
+// NewEVM constructs an EVM instance with the supplied block context, state
+// database and several configs. It meant to be used throughout the entire
+// state transition of a block, with the transaction context switched as
+// needed by calling evm.SetTxContext.
+func NewEVM(blockCtx BlockContext, statedb StateDB, chainConfig *params.ChainConfig, config Config) *EVM {
 	evm := &EVM{
 		Context:     blockCtx,
-		TxContext:   txCtx,
 		StateDB:     statedb,
 		Config:      config,
 		chainConfig: chainConfig,
@@ -132,21 +133,25 @@ func NewEVM(blockCtx BlockContext, txCtx TxContext, statedb StateDB, chainConfig
 	return evm
 }
 
+// SetTracer sets the tracer for following state transition.
+func (evm *EVM) SetTracer(tracer *tracing.Hooks) {
+	evm.Config.Tracer = tracer
+}
+
 // SetPrecompiles sets the precompiled contracts for the EVM.
 // This method is only used through RPC calls.
 // It is not thread-safe.
 func (evm *EVM) SetPrecompiles(precompiles PrecompiledContracts) {
 	evm.precompiles = precompiles
 }
 
-// Reset resets the EVM with a new transaction context.Reset
+// SetTxContext resets the EVM with a new transaction context.
 // This is not threadsafe and should only be done very cautiously.
-func (evm *EVM) Reset(txCtx TxContext, statedb StateDB) {
+func (evm *EVM) SetTxContext(txCtx TxContext) {
 	if evm.chainRules.IsEIP4762 {
-		txCtx.AccessEvents = state.NewAccessEvents(statedb.PointCache())
+		txCtx.AccessEvents = state.NewAccessEvents(evm.StateDB.PointCache())
 	}
 	evm.TxContext = txCtx
-	evm.StateDB = statedb
 }
 
 // Cancel cancels any running EVM operation. This may be called concurrently and

core/vm/gas_table_test.go

@@ -95,16 +95,16 @@ func TestEIP2200(t *testing.T) {
 			CanTransfer: func(StateDB, common.Address, *uint256.Int) bool { return true },
 			Transfer:    func(StateDB, common.Address, common.Address, *uint256.Int) {},
 		}
-		vmenv := NewEVM(vmctx, TxContext{}, statedb, params.AllEthashProtocolChanges, Config{ExtraEips: []int{2200}})
+		evm := NewEVM(vmctx, statedb, params.AllEthashProtocolChanges, Config{ExtraEips: []int{2200}})
 
-		_, gas, err := vmenv.Call(AccountRef(common.Address{}), address, nil, tt.gaspool, new(uint256.Int))
+		_, gas, err := evm.Call(AccountRef(common.Address{}), address, nil, tt.gaspool, new(uint256.Int))
 		if !errors.Is(err, tt.failure) {
 			t.Errorf("test %d: failure mismatch: have %v, want %v", i, err, tt.failure)
 		}
 		if used := tt.gaspool - gas; used != tt.used {
 			t.Errorf("test %d: gas used mismatch: have %v, want %v", i, used, tt.used)
 		}
-		if refund := vmenv.StateDB.GetRefund(); refund != tt.refund {
+		if refund := evm.StateDB.GetRefund(); refund != tt.refund {
 			t.Errorf("test %d: gas refund mismatch: have %v, want %v", i, refund, tt.refund)
 		}
 	}
@@ -151,9 +151,9 @@ func TestCreateGas(t *testing.T) {
 				config.ExtraEips = []int{3860}
 			}
 
-			vmenv := NewEVM(vmctx, TxContext{}, statedb, params.AllEthashProtocolChanges, config)
+			evm := NewEVM(vmctx, statedb, params.AllEthashProtocolChanges, config)
 			var startGas = uint64(testGas)
-			ret, gas, err := vmenv.Call(AccountRef(common.Address{}), address, nil, startGas, new(uint256.Int))
+			ret, gas, err := evm.Call(AccountRef(common.Address{}), address, nil, startGas, new(uint256.Int))
 			if err != nil {
 				return false
 			}