all: pre-allocate memory for slices and maps, close XFN-148 (#1714)

accounts/abi/abigen/bindv2.go

@@ -276,7 +276,7 @@ func parseLibraryDeps(unlinkedCode string) (res []string) {
 // onItem on each. If the callback returns an error, iteration is halted and
 // the error is returned from iterSorted.
 func iterSorted[V any](inp map[string]V, onItem func(string, V) error) error {
-	var sortedKeys []string
+	sortedKeys := make([]string, 0, len(inp))
 	for key := range inp {
 		sortedKeys = append(sortedKeys, key)
 	}

accounts/abi/argument.go

@@ -62,7 +62,7 @@ func (argument *Argument) UnmarshalJSON(data []byte) error {
 
 // NonIndexed returns the arguments with indexed arguments filtered out.
 func (arguments Arguments) NonIndexed() Arguments {
-	var ret []Argument
+	ret := make([]Argument, 0, len(arguments))
 	for _, arg := range arguments {
 		if !arg.Indexed {
 			ret = append(ret, arg)

accounts/abi/bind/v2/generate_test.go

@@ -41,7 +41,7 @@ import (
 // mutations to the binding code.
 func TestBindingGeneration(t *testing.T) {
 	matches, _ := filepath.Glob("internal/contracts/*")
-	var dirs []string
+	dirs := make([]string, 0, len(matches))
 	for _, match := range matches {
 		f, _ := os.Stat(match)
 		if f.IsDir() {
@@ -50,12 +50,6 @@ func TestBindingGeneration(t *testing.T) {
 	}
 
 	for _, dir := range dirs {
-		var (
-			abis  []string
-			bins  []string
-			types []string
-			libs  = make(map[string]string)
-		)
 		basePath := filepath.Join("internal/contracts", dir)
 		combinedJsonPath := filepath.Join(basePath, "combined-abi.json")
 		abiBytes, err := os.ReadFile(combinedJsonPath)
@@ -67,6 +61,10 @@ func TestBindingGeneration(t *testing.T) {
 			t.Fatalf("Failed to read contract information from json output: %v", err)
 		}
 
+		abis := make([]string, 0, len(contracts))
+		bins := make([]string, 0, len(contracts))
+		types := make([]string, 0, len(contracts))
+		libs := make(map[string]string, len(contracts))
 		for name, contract := range contracts {
 			// fully qualified name is of the form <solFilePath>:<type>
 			nameParts := strings.Split(name, ":")

accounts/abi/pack_test.go

@@ -45,9 +45,7 @@ func TestPack(t *testing.T) {
 			if err != nil {
 				t.Fatalf("invalid ABI definition %s, %v", inDef, err)
 			}
-			var packed []byte
-			packed, err = inAbi.Pack("method", test.unpacked)
-
+			packed, err := inAbi.Pack("method", test.unpacked)
 			if err != nil {
 				t.Fatalf("test %d (%v) failed: %v", i, test.def, err)
 			}

accounts/manager.go

@@ -65,7 +65,7 @@ type Manager struct {
 // supported backends.
 func NewManager(config *Config, backends ...Backend) *Manager {
 	// Retrieve the initial list of wallets from the backends and sort by URL
-	var wallets []Wallet
+	wallets := make([]Wallet, 0, len(backends))
 	for _, backend := range backends {
 		wallets = merge(wallets, backend.Wallets()...)
 	}

bmt/bmt.go

@@ -218,7 +218,7 @@ func (t *Tree) Draw(hash []byte, d int) string {
 	hashes = append(hashes, []string{"", fmt.Sprintf("%v", hashstr(hash)), ""})
 	total := 60
 	del := "                             "
-	var rows []string
+	rows := make([]string, 0, len(hashes)+2)
 	for i := len(hashes) - 1; i >= 0; i-- {
 		var textlen int
 		hash := hashes[i]

cmd/XDC/config.go

@@ -229,7 +229,7 @@ func makeFullNode(ctx *cli.Context) (*node.Node, ethapi.Backend, XDCConfig) {
 
 	// Create gauge with geth system and build information
 	if eth != nil { // The 'eth' backend may be nil in light mode
-		var protos []string
+		protos := make([]string, 0, len(eth.Protocols()))
 		for _, p := range eth.Protocols() {
 			protos = append(protos, fmt.Sprintf("%v/%d", p.Name, p.Version))
 		}

consensus/XDPoS/XDPoS.go

@@ -218,8 +218,8 @@ func (x *XDPoS) VerifyHeaders(chain consensus.ChainReader, headers []*types.Head
 	// Split the headers list into v1 and v2 buckets
 	var v1headers []*types.Header
 	var v2headers []*types.Header
-	var v1fullVerifies []bool
-	var v2fullVerifies []bool
+	v1fullVerifies := make([]bool, 0, len(headers))
+	v2fullVerifies := make([]bool, 0, len(headers))
 
 	for i, header := range headers {
 		switch x.config.BlockConsensusVersion(header.Number) {

consensus/XDPoS/engines/engine_v2/forensics.go

@@ -274,7 +274,7 @@ func (f *Forensics) findQCsInSameRound(quorumCerts1 []types.QuorumCert, quorumCe
 
 // Find the signer list from QC signatures
 func (f *Forensics) getQcSignerAddresses(quorumCert types.QuorumCert) []string {
-	var signerList []string
+	signerList := make([]string, 0, len(quorumCert.Signatures))
 
 	// The QC signatures are signed by votes special struct VoteForSign
 	quorumCertSignedHash := types.VoteSigHash(&types.VoteForSign{

consensus/XDPoS/utils/pool.go

@@ -74,7 +74,7 @@ func (p *Pool) PoolObjKeysList() []string {
 	p.lock.RLock()
 	defer p.lock.RUnlock()
 
-	var keyList []string
+	keyList := make([]string, 0, len(p.objList))
 	for key := range p.objList {
 		keyList = append(keyList, key)
 	}

consensus/XDPoS/utils/utils.go

@@ -38,8 +38,8 @@ func ExtractValidatorsFromBytes(byteValidators []byte) ([]int64, error) {
 		return []int64{}, fmt.Errorf("invalid byte array length %d for validators", len(byteValidators))
 	}
 	lenValidator := len(byteValidators) / M2ByteLength
-	var validators []int64
-	for i := 0; i < lenValidator; i++ {
+	validators := make([]int64, 0, lenValidator)
+	for i := range lenValidator {
 		trimByte := bytes.Trim(byteValidators[i*M2ByteLength:(i+1)*M2ByteLength], "\x00")
 		intNumber, err := strconv.ParseInt(string(trimByte), 10, 64)
 		if err != nil {

console/console.go

@@ -261,7 +261,7 @@ func (c *Console) clearHistory() {
 // consoleOutput is an override for the console.log and console.error methods to
 // stream the output into the configured output stream instead of stdout.
 func (c *Console) consoleOutput(call goja.FunctionCall) goja.Value {
-	var output []string
+	output := make([]string, 0, len(call.Arguments))
 	for _, argument := range call.Arguments {
 		output = append(output, fmt.Sprintf("%v", argument))
 	}

contracts/utils.go

@@ -275,7 +275,7 @@ func GenM2FromRandomize(randomizes []int64, lenSigners int64) ([]int64, error) {
 
 // Get validators from m2 array integer.
 func BuildValidatorFromM2(listM2 []int64) []byte {
-	var validatorBytes []byte
+	validatorBytes := make([]byte, 0, len(listM2)*utils.M2ByteLength)
 	for _, numberM2 := range listM2 {
 		// Convert number to byte.
 		m2Byte := common.LeftPadBytes(fmt.Appendf(nil, "%d", numberM2), utils.M2ByteLength)

contracts/utils_test.go

@@ -166,7 +166,7 @@ func isArrayEqual(a [][]int64, b [][]int64) bool {
 
 // Unit test for
 func TestGenM2FromRandomize(t *testing.T) {
-	var a []int64
+	a := make([]int64, 0, 11)
 	for i := 0; i <= 10; i++ {
 		a = append(a, int64(rand.Intn(9999)))
 	}

core/asm/lex_test.go

@@ -24,7 +24,7 @@ import (
 func lexAll(src string) []token {
 	ch := Lex("test.asm", []byte(src), false)
 
-	var tokens []token
+	tokens := make([]token, 0, len(ch))
 	for i := range ch {
 		tokens = append(tokens, i)
 	}

core/rawdb/database.go

@@ -39,7 +39,7 @@ type freezerdb struct {
 // Close implements io.Closer, closing both the fast key-value store as well as
 // the slow ancient tables.
 func (frdb *freezerdb) Close() error {
-	var errs []error
+	errs := make([]error, 0, 2)
 	if err := frdb.AncientStore.Close(); err != nil {
 		errs = append(errs, err)
 	}

core/state/statedb_test.go

@@ -356,7 +356,7 @@ func newTestAction(addr common.Address, r *rand.Rand) testAction {
 		},
 	}
 	action := actions[r.Intn(len(actions))]
-	var nameargs []string
+	nameargs := make([]string, 0, 1+len(action.args))
 	if !action.noAddr {
 		nameargs = append(nameargs, addr.Hex())
 	}

core/state_processor.go

@@ -68,7 +68,7 @@ func NewStateProcessor(config *params.ChainConfig, bc *BlockChain, engine consen
 // transactions failed to execute due to insufficient gas it will return an error.
 func (p *StateProcessor) Process(block *types.Block, statedb *state.StateDB, tradingState *tradingstate.TradingStateDB, cfg vm.Config, tokensFee map[common.Address]*big.Int) (types.Receipts, []*types.Log, uint64, error) {
 	var (
-		receipts    types.Receipts
+		receipts    = make([]*types.Receipt, 0, len(block.Transactions()))
 		usedGas     = new(uint64)
 		header      = block.Header()
 		blockHash   = block.Hash()

core/types/hashing.go

@@ -92,7 +92,7 @@ func DeriveSha(list DerivableList, hasher TrieHasher) common.Hash {
 	// StackTrie requires values to be inserted in increasing hash order, which is not the
 	// order that `list` provides hashes in. This insertion sequence ensures that the
 	// order is correct.
-	var indexBuf []byte
+	indexBuf := make([]byte, 0, list.Len())
 	for i := 1; i < list.Len() && i <= 0x7f; i++ {
 		indexBuf = rlp.AppendUint64(indexBuf[:0], uint64(i))
 		value := encodeForDerive(list, i, valueBuf)

core/types/transaction.go

@@ -608,7 +608,7 @@ func (s Transactions) EncodeIndex(i int, w *bytes.Buffer) {
 func TxDifference(a, b Transactions) (keep Transactions) {
 	keep = make(Transactions, 0, len(a))
 
-	remove := make(map[common.Hash]struct{})
+	remove := make(map[common.Hash]struct{}, len(b))
 	for _, tx := range b {
 		remove[tx.Hash()] = struct{}{}
 	}
@@ -626,7 +626,7 @@ func TxDifference(a, b Transactions) (keep Transactions) {
 func HashDifference(a, b []common.Hash) []common.Hash {
 	keep := make([]common.Hash, 0, len(a))
 
-	remove := make(map[common.Hash]struct{})
+	remove := make(map[common.Hash]struct{}, len(b))
 	for _, hash := range b {
 		remove[hash] = struct{}{}
 	}

core/vm/interpreter.go

@@ -127,11 +127,11 @@ func NewEVMInterpreter(evm *EVM) *EVMInterpreter {
 	default:
 		table = &frontierInstructionSet
 	}
-	var extraEips []int
 	if len(evm.Config.ExtraEips) > 0 {
 		// Deep-copy jumptable to prevent modification of opcodes in other tables
 		table = copyJumpTable(table)
 	}
+	extraEips := make([]int, 0, len(evm.Config.ExtraEips))
 	for _, eip := range evm.Config.ExtraEips {
 		if err := EnableEIP(eip, table); err != nil {
 			// Disable it, so caller can check if it's activated or not

internal/build/file.go

@@ -85,7 +85,7 @@ func HashFolder(folder string, exlude []string) (map[string][32]byte, error) {
 
 // DiffHashes compares two maps of file hashes and returns the changed files.
 func DiffHashes(a map[string][32]byte, b map[string][32]byte) []string {
-	var updates []string
+	updates := make([]string, 0, len(a)+len(b))
 
 	for file := range a {
 		if _, ok := b[file]; !ok || a[file] != b[file] {

metrics/prometheus/collector.go

@@ -140,7 +140,7 @@ func (c *collector) writeGaugeInfo(name string, value metrics.GaugeInfoValue) {
 	c.buff.WriteString(fmt.Sprintf(typeGaugeTpl, name))
 	c.buff.WriteString(name)
 	c.buff.WriteString(" ")
-	var kvs []string
+	kvs := make([]string, 0, len(value))
 	for k, v := range value {
 		kvs = append(kvs, fmt.Sprintf("%v=%q", k, v))
 	}

metrics/registry.go

@@ -49,8 +49,8 @@ type orderedRegistry struct {
 
 // Each call the given function for each registered metric.
 func (r *orderedRegistry) Each(f func(string, interface{})) {
-	var names []string
 	reg := r.registered()
+	names := make([]string, 0, len(reg))
 	for name := range reg {
 		names = append(names, name)
 	}

node/rpcstack.go

@@ -179,7 +179,7 @@ func (h *httpServer) start() error {
 	)
 
 	// Log all handlers mounted on server.
-	var paths []string
+	paths := make([]string, 0, len(h.handlerNames))
 	for path := range h.handlerNames {
 		paths = append(paths, path)
 	}

trie/sync_test.go

@@ -384,7 +384,7 @@ func TestDuplicateAvoidanceSync(t *testing.T) {
 	// The code requests are ignored here since there is no code
 	// at the testing trie.
 	paths, nodes, _ := sched.Missing(0)
-	var elements []trieElement
+	elements := make([]trieElement, 0, len(paths))
 	for i := 0; i < len(paths); i++ {
 		elements = append(elements, trieElement{
 			path:     paths[i],