eth/tracers: support for golang tracers + add golang callTracer

cmd/evm/internal/t8ntool/execution.go

@@ -96,7 +96,7 @@ type rejectedTx struct {
 // Apply applies a set of transactions to a pre-state
 func (pre *Prestate) Apply(vmConfig vm.Config, chainConfig *params.ChainConfig,
 	txs types.Transactions, miningReward int64,
-	getTracerFn func(txIndex int, txHash common.Hash) (tracer vm.Tracer, err error)) (*state.StateDB, *ExecutionResult, error) {
+	getTracerFn func(txIndex int, txHash common.Hash) (tracer vm.EVMLogger, err error)) (*state.StateDB, *ExecutionResult, error) {
 
 	// Capture errors for BLOCKHASH operation, if we haven't been supplied the
 	// required blockhashes

cmd/evm/internal/t8ntool/transition.go

@@ -89,10 +89,10 @@ func Transition(ctx *cli.Context) error {
 
 	var (
 		err     error
-		tracer  vm.Tracer
+		tracer  vm.EVMLogger
 		baseDir = ""
 	)
-	var getTracer func(txIndex int, txHash common.Hash) (vm.Tracer, error)
+	var getTracer func(txIndex int, txHash common.Hash) (vm.EVMLogger, error)
 
 	// If user specified a basedir, make sure it exists
 	if ctx.IsSet(OutputBasedir.Name) {
@@ -119,7 +119,7 @@ func Transition(ctx *cli.Context) error {
 				prevFile.Close()
 			}
 		}()
-		getTracer = func(txIndex int, txHash common.Hash) (vm.Tracer, error) {
+		getTracer = func(txIndex int, txHash common.Hash) (vm.EVMLogger, error) {
 			if prevFile != nil {
 				prevFile.Close()
 			}
@@ -131,7 +131,7 @@ func Transition(ctx *cli.Context) error {
 			return vm.NewJSONLogger(logConfig, traceFile), nil
 		}
 	} else {
-		getTracer = func(txIndex int, txHash common.Hash) (tracer vm.Tracer, err error) {
+		getTracer = func(txIndex int, txHash common.Hash) (tracer vm.EVMLogger, err error) {
 			return nil, nil
 		}
 	}

cmd/evm/runner.go

@@ -116,7 +116,7 @@ func runCmd(ctx *cli.Context) error {
 	}
 
 	var (
-		tracer        vm.Tracer
+		tracer        vm.EVMLogger
 		debugLogger   *vm.StructLogger
 		statedb       *state.StateDB
 		chainConfig   *params.ChainConfig

cmd/evm/staterunner.go

@@ -65,7 +65,7 @@ func stateTestCmd(ctx *cli.Context) error {
 		EnableReturnData: !ctx.GlobalBool(DisableReturnDataFlag.Name),
 	}
 	var (
-		tracer   vm.Tracer
+		tracer   vm.EVMLogger
 		debugger *vm.StructLogger
 	)
 	switch {

cmd/geth/main.go

@@ -39,6 +39,10 @@ import (
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/metrics"
 	"github.com/ethereum/go-ethereum/node"
+
+	// Force-load the native, to trigger registration
+	_ "github.com/ethereum/go-ethereum/eth/tracers/native"
+
 	"gopkg.in/urfave/cli.v1"
 )
 

core/vm/interpreter.go

@@ -27,11 +27,11 @@ import (
 
 // Config are the configuration options for the Interpreter
 type Config struct {
-	Debug                   bool   // Enables debugging
-	Tracer                  Tracer // Opcode logger
-	NoRecursion             bool   // Disables call, callcode, delegate call and create
-	NoBaseFee               bool   // Forces the EIP-1559 baseFee to 0 (needed for 0 price calls)
-	EnablePreimageRecording bool   // Enables recording of SHA3/keccak preimages
+	Debug                   bool      // Enables debugging
+	Tracer                  EVMLogger // Opcode logger
+	NoRecursion             bool      // Disables call, callcode, delegate call and create
+	NoBaseFee               bool      // Forces the EIP-1559 baseFee to 0 (needed for 0 price calls)
+	EnablePreimageRecording bool      // Enables recording of SHA3/keccak preimages
 
 	JumpTable [256]*operation // EVM instruction table, automatically populated if unset
 
@@ -152,9 +152,9 @@ func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (
 		pc   = uint64(0) // program counter
 		cost uint64
 		// copies used by tracer
-		pcCopy  uint64 // needed for the deferred Tracer
-		gasCopy uint64 // for Tracer to log gas remaining before execution
-		logged  bool   // deferred Tracer should ignore already logged steps
+		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
 	)
 	// Don't move this deferrred function, it's placed before the capturestate-deferred method,

core/vm/logger.go

@@ -98,12 +98,12 @@ func (s *StructLog) ErrorString() string {
 	return ""
 }
 
-// Tracer is used to collect execution traces from an EVM transaction
+// EVMLogger is used to collect execution traces from an EVM transaction
 // execution. CaptureState is called for each step of the VM with the
 // current VM state.
 // Note that reference types are actual VM data structures; make copies
 // if you need to retain them beyond the current call.
-type Tracer interface {
+type EVMLogger interface {
 	CaptureStart(env *EVM, from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int)
 	CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, rData []byte, depth int, err error)
 	CaptureEnter(typ OpCode, from common.Address, to common.Address, input []byte, gas uint64, value *big.Int)
@@ -112,7 +112,7 @@ type Tracer interface {
 	CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error)
 }
 
-// StructLogger is an EVM state logger and implements Tracer.
+// StructLogger is an EVM state logger and implements EVMLogger.
 //
 // StructLogger can capture state based on the given Log configuration and also keeps
 // a track record of modified storage which is used in reporting snapshots of the
@@ -145,7 +145,7 @@ func (l *StructLogger) Reset() {
 	l.err = nil
 }
 
-// CaptureStart implements the Tracer interface to initialize the tracing operation.
+// CaptureStart implements the EVMLogger interface to initialize the tracing operation.
 func (l *StructLogger) CaptureStart(env *EVM, from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) {
 }
 
@@ -210,7 +210,7 @@ func (l *StructLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost ui
 	l.logs = append(l.logs, log)
 }
 
-// CaptureFault implements the Tracer interface to trace an execution fault
+// CaptureFault implements the EVMLogger interface to trace an execution fault
 // while running an opcode.
 func (l *StructLogger) CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, depth int, err error) {
 }

eth/tracers/api.go

@@ -845,36 +845,34 @@ func (api *API) TraceCall(ctx context.Context, args ethapi.TransactionArgs, bloc
 func (api *API) traceTx(ctx context.Context, message core.Message, txctx *Context, vmctx vm.BlockContext, statedb *state.StateDB, config *TraceConfig) (interface{}, error) {
 	// Assemble the structured logger or the JavaScript tracer
 	var (
-		tracer    vm.Tracer
+		tracer    vm.EVMLogger
 		err       error
 		txContext = core.NewEVMTxContext(message)
 	)
 	switch {
-	case config != nil && config.Tracer != nil:
+	case config == nil:
+		tracer = vm.NewStructLogger(nil)
+	case config.Tracer != nil:
 		// Define a meaningful timeout of a single transaction trace
 		timeout := defaultTraceTimeout
 		if config.Timeout != nil {
 			if timeout, err = time.ParseDuration(*config.Timeout); err != nil {
 				return nil, err
 			}
 		}
-		// Constuct the JavaScript tracer to execute with
-		if tracer, err = New(*config.Tracer, txctx); err != nil {
+		if t, err := New(*config.Tracer, txctx); err != nil {
 			return nil, err
+		} else {
+			deadlineCtx, cancel := context.WithTimeout(ctx, timeout)
+			go func() {
+				<-deadlineCtx.Done()
+				if errors.Is(deadlineCtx.Err(), context.DeadlineExceeded) {
+					t.Stop(errors.New("execution timeout"))
+				}
+			}()
+			defer cancel()
+			tracer = t
 		}
-		// Handle timeouts and RPC cancellations
-		deadlineCtx, cancel := context.WithTimeout(ctx, timeout)
-		go func() {
-			<-deadlineCtx.Done()
-			if deadlineCtx.Err() == context.DeadlineExceeded {
-				tracer.(*Tracer).Stop(errors.New("execution timeout"))
-			}
-		}()
-		defer cancel()
-
-	case config == nil:
-		tracer = vm.NewStructLogger(nil)
-
 	default:
 		tracer = vm.NewStructLogger(config.LogConfig)
 	}
@@ -904,7 +902,7 @@ func (api *API) traceTx(ctx context.Context, message core.Message, txctx *Contex
 			StructLogs:  ethapi.FormatLogs(tracer.StructLogs()),
 		}, nil
 
-	case *Tracer:
+	case Tracer:
 		return tracer.GetResult()
 
 	default:

eth/tracers/native/call.go

@@ -0,0 +1,166 @@
+// Copyright 2021 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"
+	"errors"
+	"math/big"
+	"strconv"
+	"strings"
+	"sync/atomic"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/vm"
+	"github.com/ethereum/go-ethereum/eth/tracers"
+)
+
+func init() {
+	tracers.RegisterNativeTracer("callTracerNative", NewCallTracer)
+}
+
+type callFrame struct {
+	Type    string      `json:"type"`
+	From    string      `json:"from"`
+	To      string      `json:"to,omitempty"`
+	Value   string      `json:"value,omitempty"`
+	Gas     string      `json:"gas"`
+	GasUsed string      `json:"gasUsed"`
+	Input   string      `json:"input"`
+	Output  string      `json:"output,omitempty"`
+	Error   string      `json:"error,omitempty"`
+	Calls   []callFrame `json:"calls,omitempty"`
+}
+
+type callTracer struct {
+	callstack []callFrame
+	interrupt uint32 // Atomic flag to signal execution interruption
+	reason    error  // Textual reason for the interruption
+}
+
+// NewCallTracer returns a native go tracer which tracks
+// call frames of a tx, and implements vm.EVMLogger.
+func NewCallTracer() tracers.Tracer {
+	// First callframe contains tx context info
+	// and is populated on start and end.
+	t := &callTracer{callstack: make([]callFrame, 1)}
+	return t
+}
+
+func (t *callTracer) CaptureStart(env *vm.EVM, from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) {
+	t.callstack[0] = callFrame{
+		Type:  "CALL",
+		From:  addrToHex(from),
+		To:    addrToHex(to),
+		Input: bytesToHex(input),
+		Gas:   uintToHex(gas),
+		Value: bigToHex(value),
+	}
+	if create {
+		t.callstack[0].Type = "CREATE"
+	}
+}
+
+func (t *callTracer) CaptureEnd(output []byte, gasUsed uint64, _ time.Duration, err error) {
+	t.callstack[0].Output = bytesToHex(output)
+	t.callstack[0].GasUsed = uintToHex(gasUsed)
+	if err != nil {
+		t.callstack[0].Error = err.Error()
+	}
+}
+
+func (t *callTracer) CaptureState(env *vm.EVM, pc uint64, op vm.OpCode, gas, cost uint64, scope *vm.ScopeContext, rData []byte, depth int, err error) {
+}
+
+func (t *callTracer) CaptureFault(env *vm.EVM, pc uint64, op vm.OpCode, gas, cost uint64, _ *vm.ScopeContext, depth int, err error) {
+}
+
+func (t *callTracer) CaptureEnter(typ 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 {
+		// TODO: env.Cancel()
+		return
+	}
+
+	call := callFrame{
+		Type:  typ.String(),
+		From:  addrToHex(from),
+		To:    addrToHex(to),
+		Input: bytesToHex(input),
+		Gas:   uintToHex(gas),
+		Value: bigToHex(value),
+	}
+	t.callstack = append(t.callstack, call)
+}
+
+func (t *callTracer) CaptureExit(output []byte, gasUsed uint64, err error) {
+	size := len(t.callstack)
+	if size <= 1 {
+		return
+	}
+	// pop call
+	call := t.callstack[size-1]
+	t.callstack = t.callstack[:size-1]
+	size -= 1
+
+	call.GasUsed = uintToHex(gasUsed)
+	if err == nil {
+		call.Output = bytesToHex(output)
+	} else {
+		call.Error = err.Error()
+		if call.Type == "CREATE" || call.Type == "CREATE2" {
+			call.To = ""
+		}
+	}
+	t.callstack[size-1].Calls = append(t.callstack[size-1].Calls, call)
+}
+
+func (t *callTracer) GetResult() (json.RawMessage, error) {
+	if len(t.callstack) != 1 {
+		return nil, errors.New("incorrect number of top-level calls")
+	}
+	res, err := json.Marshal(t.callstack[0])
+	if err != nil {
+		return nil, err
+	}
+	return json.RawMessage(res), t.reason
+}
+
+func (t *callTracer) Stop(err error) {
+	t.reason = err
+	atomic.StoreUint32(&t.interrupt, 1)
+}
+
+func bytesToHex(s []byte) string {
+	return "0x" + common.Bytes2Hex(s)
+}
+
+func bigToHex(n *big.Int) string {
+	if n == nil {
+		return ""
+	}
+	return "0x" + n.Text(16)
+}
+
+func uintToHex(n uint64) string {
+	return "0x" + strconv.FormatUint(n, 16)
+}
+
+func addrToHex(a common.Address) string {
+	return strings.ToLower(a.Hex())
+}