capacity at append in for, where it van precalculated

core/blockchain.go

@@ -1352,7 +1352,7 @@ const (
 // will be directly stored in the ancient, getting rid of the chain migration.
 func (bc *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain []rlp.RawValue, ancientLimit uint64) (int, error) {
 	// Verify the supplied headers before insertion without lock
-	var headers []*types.Header
+	headers := make([]*types.Header, 0, len(blockChain))
 	for _, block := range blockChain {
 		headers = append(headers, block.Header())
 		// Here we also validate that blob transactions in the block do not
@@ -2210,7 +2210,7 @@ func (bc *BlockChain) insertSideChain(block *types.Block, it *insertIterator, ma
 	}
 	// Import all the pruned blocks to make the state available
 	var (
-		blocks []*types.Block
+		blocks = make([]*types.Block, 0, len(hashes))
 		memory uint64
 	)
 	for i := len(hashes) - 1; i >= 0; i-- {

core/rawdb/ancient_utils.go

@@ -53,6 +53,7 @@ func (info *freezerInfo) size() common.StorageSize {
 
 func inspect(name string, order map[string]freezerTableConfig, reader ethdb.AncientReader) (freezerInfo, error) {
 	info := freezerInfo{name: name}
+	info.sizes = make([]tableSize, 0, len(order))
 	for t := range order {
 		size, err := reader.AncientSize(t)
 		if err != nil {
@@ -78,7 +79,7 @@ func inspect(name string, order map[string]freezerTableConfig, reader ethdb.Anci
 
 // inspectFreezers inspects all freezers registered in the system.
 func inspectFreezers(db ethdb.Database) ([]freezerInfo, error) {
-	var infos []freezerInfo
+	var infos []freezerInfo = make([]freezerInfo, 0, len(freezers))
 	for _, freezer := range freezers {
 		switch freezer {
 		case ChainFreezerName:

core/rawdb/chain_iterator.go

@@ -148,7 +148,7 @@ func iterateTransactions(db ethdb.Database, from uint64, to uint64, reverse bool
 				log.Warn("Failed to decode block body", "block", data.number, "error", err)
 				return
 			}
-			var hashes []common.Hash
+			var hashes []common.Hash = make([]common.Hash, 0, len(body.Transactions))
 			for _, tx := range body.Transactions {
 				hashes = append(hashes, tx.Hash())
 			}

core/rawdb/freezer_table.go

@@ -936,7 +936,7 @@ func (t *freezerTable) getIndices(from, count uint64) ([]*indexEntry, error) {
 		return nil, err
 	}
 	var (
-		indices []*indexEntry
+		indices = make([]*indexEntry, 0, count+1)
 		offset  int
 	)
 	for i := from; i <= from+count; i++ {

core/txpool/blobpool/blobpool.go

@@ -521,7 +521,7 @@ func (p *BlobPool) parseTransaction(id uint64, size uint32, blob []byte) error {
 }
 
 // recheck verifies the pool's content for a specific account and drops anything
-// that does not fit anymore (dangling or filled nonce, overdraft).
+// that does not fit anymore (dangling or filled nonce, overdraft).  // TODO split long method in smaller parts
 func (p *BlobPool) recheck(addr common.Address, inclusions map[common.Hash]uint64) {
 	// Sort the transactions belonging to the account so reinjects can be simpler
 	txs := p.index[addr]
@@ -541,8 +541,8 @@ func (p *BlobPool) recheck(addr common.Address, inclusions map[common.Hash]uint6
 	)
 	if gapped || filled {
 		var (
-			ids    []uint64
+			ids    []uint64 = make([]uint64, 0, len(txs))
-			nonces []uint64
+			nonces []uint64 = make([]uint64, 0, len(txs))
 		)
 		for i := 0; i < len(txs); i++ {
 			ids = append(ids, txs[i].id)
@@ -659,8 +659,8 @@ func (p *BlobPool) recheck(addr common.Address, inclusions map[common.Hash]uint6
 		}
 		// Otherwise if there's a nonce gap evict all later transactions
 		var (
-			ids    []uint64
+			ids    []uint64 = make([]uint64, 0, len(txs))
-			nonces []uint64
+			nonces []uint64 = make([]uint64, 0, len(txs))
 		)
 		for j := i; j < len(txs); j++ {
 			ids = append(ids, txs[j].id)

core/vm/contracts.go

@@ -645,9 +645,10 @@ func runBn256Pairing(input []byte) ([]byte, error) {
 		return nil, errBadPairingInput
 	}
 	// Convert the input into a set of coordinates
+	howMuch := len(input) / 192
 	var (
-		cs []*bn256.G1
+		cs []*bn256.G1 = make([]*bn256.G1, 0, howMuch)
-		ts []*bn256.G2
+		ts []*bn256.G2 = make([]*bn256.G2, 0, howMuch)
 	)
 	for i := 0; i < len(input); i += 192 {
 		c, err := newCurvePoint(input[i : i+64])
@@ -976,8 +977,8 @@ func (c *bls12381Pairing) Run(input []byte) ([]byte, error) {
 	}
 
 	var (
-		p []bls12381.G1Affine
+		p []bls12381.G1Affine = make([]bls12381.G1Affine, 0, k)
-		q []bls12381.G2Affine
+		q []bls12381.G2Affine = make([]bls12381.G2Affine, 0, k)
 	)
 
 	// Decode pairs

core/vm/eips.go

@@ -60,7 +60,7 @@ func ValidEip(eipNum int) bool {
 	return ok
 }
 func ActivateableEips() []string {
-	var nums []string
+	nums := make([]string, 0, len(activators))
 	for k := range activators {
 		nums = append(nums, fmt.Sprintf("%d", k))
 	}

core/vm/interpreter.go

@@ -136,11 +136,12 @@ func NewEVMInterpreter(evm *EVM) *EVMInterpreter {
 	default:
 		table = &frontierInstructionSet
 	}
-	var extraEips []int
+	extraEips := make([]int, 0, len(evm.Config.ExtraEips))
 	if len(evm.Config.ExtraEips) > 0 {
 		// Deep-copy jumptable to prevent modification of opcodes in other tables
 		table = copyJumpTable(table)
 	}
+
 	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