Port call tracer with log to bsc

Port ethereum/go-ethereum#25991 to bsc,
which adds `withLog` parameter to output event logs

Author: cannium

eth/tracers/native/call.go

@@ -25,38 +25,93 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/ethereum/go-ethereum/accounts/abi"
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/eth/tracers"
 )
 
+//go:generate go run github.com/fjl/gencodec -type callFrame -field-override callFrameMarshaling -out gen_callframe_json.go
+
 func init() {
 	register("callTracer", newCallTracer)
 }
 
+type callLog struct {
+	Address common.Address `json:"address"`
+	Topics  []common.Hash  `json:"topics"`
+	Data    hexutil.Bytes  `json:"data"`
+}
+
 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     vm.OpCode      `json:"-"`
+	From     common.Address `json:"from"`
+	Gas      uint64         `json:"gas"`
+	GasUsed  uint64         `json:"gasUsed"`
+	To       common.Address `json:"to,omitempty" rlp:"optional"`
+	Input    []byte         `json:"input" rlp:"optional"`
+	Output   []byte         `json:"output,omitempty" rlp:"optional"`
+	Error    string         `json:"error,omitempty" rlp:"optional"`
+	Revertal string         `json:"revertReason,omitempty"`
+	Calls    []callFrame    `json:"calls,omitempty" rlp:"optional"`
+	Logs     []callLog      `json:"logs,omitempty" rlp:"optional"`
+	// Placed at end on purpose. The RLP will be decoded to 0 instead of
+	// nil if there are non-empty elements after in the struct.
+	Value *big.Int `json:"value,omitempty" rlp:"optional"`
+}
+
+func (f callFrame) TypeString() string {
+	return f.Type.String()
+}
+
+func (f callFrame) failed() bool {
+	return len(f.Error) > 0
+}
+
+func (f *callFrame) processOutput(output []byte, err error) {
+	output = common.CopyBytes(output)
+	if err == nil {
+		f.Output = output
+		return
+	}
+	f.Error = err.Error()
+	if f.Type == vm.CREATE || f.Type == vm.CREATE2 {
+		f.To = common.Address{}
+	}
+	if !errors.Is(err, vm.ErrExecutionReverted) || len(output) == 0 {
+		return
+	}
+	f.Output = output
+	if len(output) < 4 {
+		return
+	}
+	if unpacked, err := abi.UnpackRevert(output); err == nil {
+		f.Revertal = unpacked
+	}
+}
+
+type callFrameMarshaling struct {
+	TypeString string `json:"type"`
+	Gas        hexutil.Uint64
+	GasUsed    hexutil.Uint64
+	Value      *hexutil.Big
+	Input      hexutil.Bytes
+	Output     hexutil.Bytes
 }
 
 type callTracer struct {
-	env       *vm.EVM
+	noopTracer
 	callstack []callFrame
 	config    callTracerConfig
+	gasLimit  uint64
 	interrupt uint32 // Atomic flag to signal execution interruption
 	reason    error  // Textual reason for the interruption
 }
 
 type callTracerConfig struct {
 	OnlyTopCall bool `json:"onlyTopCall"` // If true, call tracer won't collect any subcalls
+	WithLog     bool `json:"withLog"`     // If true, call tracer will collect event logs
 }
 
 // newCallTracer returns a native go tracer which tracks
@@ -75,39 +130,58 @@ 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:  "CALL",
-		From:  addrToHex(from),
-		To:    addrToHex(to),
-		Input: bytesToHex(input),
-		Gas:   uintToHex(gas),
-		Value: bigToHex(value),
+		Type:  vm.CALL,
+		From:  from,
+		To:    to,
+		Input: common.CopyBytes(input),
+		Gas:   gas,
+		Value: value,
 	}
 	if create {
-		t.callstack[0].Type = "CREATE"
+		t.callstack[0].Type = vm.CREATE
 	}
 }
 
 // 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].GasUsed = uintToHex(gasUsed)
-	if err != nil {
-		t.callstack[0].Error = err.Error()
-		if err.Error() == "execution reverted" && len(output) > 0 {
-			t.callstack[0].Output = bytesToHex(output)
-		}
-	} else {
-		t.callstack[0].Output = bytesToHex(output)
-	}
+func (t *callTracer) CaptureEnd(output []byte, gasUsed uint64, d time.Duration, err error) {
+	t.callstack[0].processOutput(output, err)
 }
 
 // CaptureState implements the EVMLogger interface to trace a single step of VM execution.
 func (t *callTracer) CaptureState(pc uint64, op vm.OpCode, gas, cost uint64, scope *vm.ScopeContext, rData []byte, depth int, err error) {
-}
+	// Only logs need to be captured via opcode processing
+	if !t.config.WithLog {
+		return
+	}
+	// Avoid processing nested calls when only caring about top call
+	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)
+
+		stack := scope.Stack
+		stackData := stack.Data()
+
+		// Don't modify the stack
+		mStart := stackData[len(stackData)-1]
+		mSize := stackData[len(stackData)-2]
+		topics := make([]common.Hash, size)
+		for i := 0; i < size; i++ {
+			topic := stackData[len(stackData)-2-(i+1)]
+			topics[i] = common.Hash(topic.Bytes32())
+		}
 
-// CaptureFault implements the EVMLogger interface to trace an execution fault.
-func (t *callTracer) CaptureFault(pc uint64, op vm.OpCode, gas, cost uint64, _ *vm.ScopeContext, depth int, err error) {
+		data := scope.Memory.GetCopy(int64(mStart.Uint64()), int64(mSize.Uint64()))
+		log := callLog{Address: scope.Contract.Address(), Topics: topics, Data: hexutil.Bytes(data)}
+		t.callstack[len(t.callstack)-1].Logs = append(t.callstack[len(t.callstack)-1].Logs, log)
+	}
 }
 
 // CaptureEnter is called when EVM enters a new scope (via call, create or selfdestruct).
@@ -117,17 +191,16 @@ 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
 	}
 
 	call := callFrame{
-		Type:  typ.String(),
-		From:  addrToHex(from),
-		To:    addrToHex(to),
-		Input: bytesToHex(input),
-		Gas:   uintToHex(gas),
-		Value: bigToHex(value),
+		Type:  typ,
+		From:  from,
+		To:    to,
+		Input: common.CopyBytes(input),
+		Gas:   gas,
+		Value: value,
 	}
 	t.callstack = append(t.callstack, call)
 }
@@ -147,21 +220,22 @@ func (t *callTracer) CaptureExit(output []byte, gasUsed uint64, err error) {
 	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 = ""
-		}
-	}
+	call.GasUsed = gasUsed
+	call.processOutput(output, err)
 	t.callstack[size-1].Calls = append(t.callstack[size-1].Calls, call)
 }
 
-func (*callTracer) CaptureTxStart(gasLimit uint64) {}
+func (t *callTracer) CaptureTxStart(gasLimit uint64) {
+	t.gasLimit = gasLimit
+}
 
-func (*callTracer) CaptureTxEnd(restGas uint64) {}
+func (t *callTracer) CaptureTxEnd(restGas uint64) {
+	t.callstack[0].GasUsed = t.gasLimit - restGas
+	if t.config.WithLog {
+		// Logs are not emitted when the call fails
+		clearFailedLogs(&t.callstack[0], false)
+	}
+}
 
 // GetResult returns the json-encoded nested list of call traces, and any
 // error arising from the encoding or forceful termination (via `Stop`).
@@ -182,6 +256,19 @@ func (t *callTracer) Stop(err error) {
 	atomic.StoreUint32(&t.interrupt, 1)
 }
 
+// clearFailedLogs clears the logs of a callframe and all its children
+// in case of execution failure.
+func clearFailedLogs(cf *callFrame, parentFailed bool) {
+	failed := cf.failed() || parentFailed
+	// Clear own logs
+	if failed {
+		cf.Logs = nil
+	}
+	for i := range cf.Calls {
+		clearFailedLogs(&cf.Calls[i], failed)
+	}
+}
+
 func bytesToHex(s []byte) string {
 	return "0x" + common.Bytes2Hex(s)
 }