refactor: reduce number of heap allocations in tracing (#952)

Author: omerfirmak

core/types/l2trace.go

@@ -70,7 +70,7 @@ type ExecutionResult struct {
 	// currently they are just `from` and `to` account
 	AccountsAfter []*AccountWrapper `json:"accountAfter"`
 
-	StructLogs []*StructLogRes `json:"structLogs"`
+	StructLogs []StructLogRes  `json:"structLogs"`
 	CallTrace  json.RawMessage `json:"callTrace"`
 }
 
@@ -91,8 +91,8 @@ type StructLogRes struct {
 
 // NewStructLogResBasic Basic StructLogRes skeleton, Stack&Memory&Storage&ExtraData are separated from it for GC optimization;
 // still need to fill in with Stack&Memory&Storage&ExtraData
-func NewStructLogResBasic(pc uint64, op string, gas, gasCost uint64, depth int, refundCounter uint64, err error) *StructLogRes {
-	logRes := &StructLogRes{
+func NewStructLogResBasic(pc uint64, op string, gas, gasCost uint64, depth int, refundCounter uint64, err error) StructLogRes {
+	logRes := StructLogRes{
 		Pc:            pc,
 		Op:            op,
 		Gas:           gas,

core/vm/logger.go

@@ -79,8 +79,8 @@ type StructLog struct {
 	Err           error                       `json:"-"`
 }
 
-func NewStructlog(pc uint64, op OpCode, gas, cost uint64, depth int, err error) *StructLog {
-	return &StructLog{
+func NewStructlog(pc uint64, op OpCode, gas, cost uint64, depth int, err error) StructLog {
+	return StructLog{
 		Pc:      pc,
 		Op:      op,
 		Gas:     gas,
@@ -90,14 +90,6 @@ func NewStructlog(pc uint64, op OpCode, gas, cost uint64, depth int, err error)
 	}
 }
 
-func (s *StructLog) clean() {
-	s.Memory.Reset()
-	s.Stack = s.Stack[:0]
-	s.ReturnData.Reset()
-	s.Storage = nil
-	s.Err = nil
-}
-
 // overrides for gencodec
 type structLogMarshaling struct {
 	Gas         math.HexOrDecimal64
@@ -159,7 +151,7 @@ type StructLogger struct {
 	createdAccount *types.AccountWrapper
 
 	callStackLogInd []int
-	logs            []*StructLog
+	logs            []StructLog
 	output          []byte
 	err             error
 }
@@ -359,7 +351,7 @@ func (l *StructLogger) TracedBytecodes() map[common.Hash]CodeInfo {
 func (l *StructLogger) CreatedAccount() *types.AccountWrapper { return l.createdAccount }
 
 // StructLogs returns the captured log entries.
-func (l *StructLogger) StructLogs() []*StructLog { return l.logs }
+func (l *StructLogger) StructLogs() []StructLog { return l.logs }
 
 // Error returns the VM error captured by the trace.
 func (l *StructLogger) Error() error { return l.err }
@@ -368,7 +360,7 @@ func (l *StructLogger) Error() error { return l.err }
 func (l *StructLogger) Output() []byte { return l.output }
 
 // WriteTrace writes a formatted trace to the given writer
-func WriteTrace(writer io.Writer, logs []*StructLog) {
+func WriteTrace(writer io.Writer, logs []StructLog) {
 	for _, log := range logs {
 		fmt.Fprintf(writer, "%-16spc=%08d gas=%v cost=%v", log.Op, log.Pc, log.Gas, log.GasCost)
 		if log.Err != nil {
@@ -488,8 +480,8 @@ func (t *mdLogger) CaptureEnter(typ OpCode, from common.Address, to common.Addre
 func (t *mdLogger) CaptureExit(output []byte, gasUsed uint64, err error) {}
 
 // FormatLogs formats EVM returned structured logs for json output
-func FormatLogs(logs []*StructLog) []*types.StructLogRes {
-	formatted := make([]*types.StructLogRes, 0, len(logs))
+func FormatLogs(logs []StructLog) []types.StructLogRes {
+	formatted := make([]types.StructLogRes, 0, len(logs))
 
 	for _, trace := range logs {
 		logRes := types.NewStructLogResBasic(trace.Pc, trace.Op.String(), trace.Gas, trace.GasCost, trace.Depth, trace.RefundCounter, trace.Err)

eth/tracers/api_test.go

@@ -227,7 +227,7 @@ func TestTraceCall(t *testing.T) {
 				Gas:         params.TxGas,
 				Failed:      false,
 				ReturnValue: "",
-				StructLogs:  []*types.StructLogRes{},
+				StructLogs:  []types.StructLogRes{},
 			},
 		},
 		// Standard JSON trace upon the head, plain transfer.
@@ -245,7 +245,7 @@ func TestTraceCall(t *testing.T) {
 				Gas:         params.TxGas,
 				Failed:      false,
 				ReturnValue: "",
-				StructLogs:  []*types.StructLogRes{},
+				StructLogs:  []types.StructLogRes{},
 			},
 		},
 		// Standard JSON trace upon the non-existent block, error expects
@@ -275,7 +275,7 @@ func TestTraceCall(t *testing.T) {
 				Gas:         params.TxGas,
 				Failed:      false,
 				ReturnValue: "",
-				StructLogs:  []*types.StructLogRes{},
+				StructLogs:  []types.StructLogRes{},
 			},
 		},
 		// Standard JSON trace upon the pending block
@@ -293,7 +293,7 @@ func TestTraceCall(t *testing.T) {
 				Gas:         params.TxGas,
 				Failed:      false,
 				ReturnValue: "",
-				StructLogs:  []*types.StructLogRes{},
+				StructLogs:  []types.StructLogRes{},
 			},
 		},
 	}
@@ -347,7 +347,7 @@ func TestTraceTransaction(t *testing.T) {
 		Gas:         params.TxGas,
 		Failed:      false,
 		ReturnValue: "",
-		StructLogs:  []*types.StructLogRes{},
+		StructLogs:  []types.StructLogRes{},
 	}) {
 		t.Error("Transaction tracing result is different")
 	}

params/version.go

@@ -24,7 +24,7 @@ import (
 const (
 	VersionMajor = 5         // Major version component of the current release
 	VersionMinor = 5         // Minor version component of the current release
-	VersionPatch = 19        // Patch version component of the current release
+	VersionPatch = 20        // Patch version component of the current release
 	VersionMeta  = "mainnet" // Version metadata to append to the version string
 )