eth/tracers: add multiplexing tracer (#26086)

* eth/tracers: add native multiplexing tracer

* minor improv callTracer

* mv evm cancellation to api

eth/tracers/api.go

@@ -911,6 +911,8 @@ func (api *API) traceTx(ctx context.Context, message core.Message, txctx *Contex
 			return nil, err
 		}
 	}
+	vmenv := vm.NewEVM(vmctx, txContext, statedb, api.backend.ChainConfig(), vm.Config{Debug: true, Tracer: tracer, NoBaseFee: true})
+
 	// Define a meaningful timeout of a single transaction trace
 	if config.Timeout != nil {
 		if timeout, err = time.ParseDuration(*config.Timeout); err != nil {
@@ -922,12 +924,12 @@ func (api *API) traceTx(ctx context.Context, message core.Message, txctx *Contex
 		<-deadlineCtx.Done()
 		if errors.Is(deadlineCtx.Err(), context.DeadlineExceeded) {
 			tracer.Stop(errors.New("execution timeout"))
+			// Stop evm execution. Note cancellation is not necessarily immediate.
+			vmenv.Cancel()
 		}
 	}()
 	defer cancel()
 
-	// Run the transaction with tracing enabled.
-	vmenv := vm.NewEVM(vmctx, txContext, statedb, api.backend.ChainConfig(), vm.Config{Debug: true, Tracer: tracer, NoBaseFee: true})
 	// Call Prepare to clear out the statedb access list
 	statedb.Prepare(txctx.TxHash, txctx.TxIndex)
 	if _, err = core.ApplyMessage(vmenv, message, new(core.GasPool).AddGas(message.Gas())); err != nil {

eth/tracers/logger/logger.go

@@ -151,7 +151,6 @@ func (l *StructLogger) CaptureStart(env *vm.EVM, from common.Address, to common.
 func (l *StructLogger) CaptureState(pc uint64, op vm.OpCode, gas, cost uint64, scope *vm.ScopeContext, rData []byte, depth int, err error) {
 	// If tracing was interrupted, set the error and stop
 	if atomic.LoadUint32(&l.interrupt) > 0 {
-		l.env.Cancel()
 		return
 	}
 	// check if already accumulated the specified number of logs

eth/tracers/native/4byte.go

@@ -47,7 +47,6 @@ func init() {
 //	  0xc281d19e-0: 1
 //	}
 type fourByteTracer struct {
-	env               *vm.EVM
 	ids               map[string]int   // ids aggregates the 4byte ids found
 	interrupt         uint32           // Atomic flag to signal execution interruption
 	reason            error            // Textual reason for the interruption
@@ -81,8 +80,6 @@ func (t *fourByteTracer) store(id []byte, size int) {
 
 // CaptureStart implements the EVMLogger interface to initialize the tracing operation.
 func (t *fourByteTracer) CaptureStart(env *vm.EVM, from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) {
-	t.env = env
-
 	// Update list of precompiles based on current block
 	rules := env.ChainConfig().Rules(env.Context.BlockNumber, env.Context.Random != nil)
 	t.activePrecompiles = vm.ActivePrecompiles(rules)
@@ -101,7 +98,6 @@ func (t *fourByteTracer) CaptureState(pc uint64, op vm.OpCode, gas, cost uint64,
 func (t *fourByteTracer) CaptureEnter(op vm.OpCode, from common.Address, to common.Address, input []byte, gas uint64, value *big.Int) {
 	// Skip if tracing was interrupted
 	if atomic.LoadUint32(&t.interrupt) > 0 {
-		t.env.Cancel()
 		return
 	}
 	if len(input) < 4 {

eth/tracers/native/call.go

@@ -67,7 +67,7 @@ func (f callFrame) failed() bool {
 	return len(f.Error) > 0
 }
 
-func (f *callFrame) capture(output []byte, err error) {
+func (f *callFrame) processOutput(output []byte, err error) {
 	output = common.CopyBytes(output)
 	if err == nil {
 		f.Output = output
@@ -99,7 +99,6 @@ type callFrameMarshaling struct {
 }
 
 type callTracer struct {
-	env       *vm.EVM
 	callstack []callFrame
 	config    callTracerConfig
 	gasLimit  uint64
@@ -128,7 +127,6 @@ func newCallTracer(ctx *tracers.Context, cfg json.RawMessage) (tracers.Tracer, e
 
 // CaptureStart implements the EVMLogger interface to initialize the tracing operation.
 func (t *callTracer) CaptureStart(env *vm.EVM, from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) {
-	t.env = env
 	t.callstack[0] = callFrame{
 		Type:  vm.CALL,
 		From:  from,
@@ -144,7 +142,7 @@ func (t *callTracer) CaptureStart(env *vm.EVM, from common.Address, to common.Ad
 
 // CaptureEnd is called after the call finishes to finalize the tracing.
 func (t *callTracer) CaptureEnd(output []byte, gasUsed uint64, _ time.Duration, err error) {
-	t.callstack[0].capture(output, err)
+	t.callstack[0].processOutput(output, err)
 }
 
 // CaptureState implements the EVMLogger interface to trace a single step of VM execution.
@@ -157,6 +155,10 @@ func (t *callTracer) CaptureState(pc uint64, op vm.OpCode, gas, cost uint64, sco
 	if t.config.OnlyTopCall && depth > 0 {
 		return
 	}
+	// Skip if tracing was interrupted
+	if atomic.LoadUint32(&t.interrupt) > 0 {
+		return
+	}
 	switch op {
 	case vm.LOG0, vm.LOG1, vm.LOG2, vm.LOG3, vm.LOG4:
 		size := int(op - vm.LOG0)
@@ -190,7 +192,6 @@ func (t *callTracer) CaptureEnter(typ vm.OpCode, from common.Address, to common.
 	}
 	// Skip if tracing was interrupted
 	if atomic.LoadUint32(&t.interrupt) > 0 {
-		t.env.Cancel()
 		return
 	}
 
@@ -221,7 +222,7 @@ func (t *callTracer) CaptureExit(output []byte, gasUsed uint64, err error) {
 	size -= 1
 
 	call.GasUsed = gasUsed
-	call.capture(output, err)
+	call.processOutput(output, err)
 	t.callstack[size-1].Calls = append(t.callstack[size-1].Calls, call)
 }
 

eth/tracers/native/mux.go

@@ -0,0 +1,139 @@
+// Copyright 2022 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 native
+
+import (
+	"encoding/json"
+	"math/big"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/vm"
+	"github.com/ethereum/go-ethereum/eth/tracers"
+)
+
+func init() {
+	register("muxTracer", newMuxTracer)
+}
+
+// muxTracer is a go implementation of the Tracer interface which
+// runs multiple tracers in one go.
+type muxTracer struct {
+	names   []string
+	tracers []tracers.Tracer
+}
+
+// newMuxTracer returns a new mux tracer.
+func newMuxTracer(ctx *tracers.Context, cfg json.RawMessage) (tracers.Tracer, error) {
+	var config map[string]json.RawMessage
+	if cfg != nil {
+		if err := json.Unmarshal(cfg, &config); err != nil {
+			return nil, err
+		}
+	}
+	objects := make([]tracers.Tracer, 0, len(config))
+	names := make([]string, 0, len(config))
+	for k, v := range config {
+		t, err := tracers.New(k, ctx, v)
+		if err != nil {
+			return nil, err
+		}
+		objects = append(objects, t)
+		names = append(names, k)
+	}
+
+	return &muxTracer{names: names, tracers: objects}, nil
+}
+
+// CaptureStart implements the EVMLogger interface to initialize the tracing operation.
+func (t *muxTracer) CaptureStart(env *vm.EVM, from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) {
+	for _, t := range t.tracers {
+		t.CaptureStart(env, from, to, create, input, gas, value)
+	}
+}
+
+// CaptureEnd is called after the call finishes to finalize the tracing.
+func (t *muxTracer) CaptureEnd(output []byte, gasUsed uint64, elapsed time.Duration, err error) {
+	for _, t := range t.tracers {
+		t.CaptureEnd(output, gasUsed, elapsed, err)
+	}
+}
+
+// CaptureState implements the EVMLogger interface to trace a single step of VM execution.
+func (t *muxTracer) CaptureState(pc uint64, op vm.OpCode, gas, cost uint64, scope *vm.ScopeContext, rData []byte, depth int, err error) {
+	for _, t := range t.tracers {
+		t.CaptureState(pc, op, gas, cost, scope, rData, depth, err)
+	}
+}
+
+// CaptureFault implements the EVMLogger interface to trace an execution fault.
+func (t *muxTracer) CaptureFault(pc uint64, op vm.OpCode, gas, cost uint64, scope *vm.ScopeContext, depth int, err error) {
+	for _, t := range t.tracers {
+		t.CaptureFault(pc, op, gas, cost, scope, depth, err)
+	}
+}
+
+// CaptureEnter is called when EVM enters a new scope (via call, create or selfdestruct).
+func (t *muxTracer) CaptureEnter(typ vm.OpCode, from common.Address, to common.Address, input []byte, gas uint64, value *big.Int) {
+	for _, t := range t.tracers {
+		t.CaptureEnter(typ, from, to, input, gas, value)
+	}
+}
+
+// CaptureExit is called when EVM exits a scope, even if the scope didn't
+// execute any code.
+func (t *muxTracer) CaptureExit(output []byte, gasUsed uint64, err error) {
+	for _, t := range t.tracers {
+		t.CaptureExit(output, gasUsed, err)
+	}
+}
+
+func (t *muxTracer) CaptureTxStart(gasLimit uint64) {
+	for _, t := range t.tracers {
+		t.CaptureTxStart(gasLimit)
+	}
+}
+
+func (t *muxTracer) CaptureTxEnd(restGas uint64) {
+	for _, t := range t.tracers {
+		t.CaptureTxEnd(restGas)
+	}
+}
+
+// GetResult returns an empty json object.
+func (t *muxTracer) GetResult() (json.RawMessage, error) {
+	resObject := make(map[string]json.RawMessage)
+	for i, tt := range t.tracers {
+		r, err := tt.GetResult()
+		if err != nil {
+			return nil, err
+		}
+		resObject[t.names[i]] = r
+	}
+	res, err := json.Marshal(resObject)
+	if err != nil {
+		return nil, err
+	}
+	return res, nil
+}
+
+// Stop terminates execution of the tracer at the first opportune moment.
+func (t *muxTracer) Stop(err error) {
+	for _, t := range t.tracers {
+		t.Stop(err)
+	}
+}