core/vm: clear linter warnings (#17057)

* core/vm: clear linter warnings

* core/vm: review input

* core/vm.go: revert lint in noop as per request

9 files changed, 51 insertions, 30 deletions

diff --git a/core/vm/errors.go b/core/vm/errors.go
index b19366be0..ea33f13f3 100644
--- a/core/vm/errors.go
+++ b/core/vm/errors.go
@@ -18,6 +18,7 @@ package vm
 
 import "errors"
 
+// List execution errors
 var (
 	ErrOutOfGas                 = errors.New("out of gas")
 	ErrCodeStoreOutOfGas        = errors.New("contract creation code storage out of gas")
diff --git a/core/vm/evm.go b/core/vm/evm.go
index ea4620974..69c8ec478 100644
--- a/core/vm/evm.go
+++ b/core/vm/evm.go
@@ -31,8 +31,10 @@ import (
 var emptyCodeHash = crypto.Keccak256Hash(nil)
 
 type (
+	// CanTransferFunc is the signature of a transfer guard function
 	CanTransferFunc func(StateDB, common.Address, *big.Int) bool
-	TransferFunc    func(StateDB, common.Address, common.Address, *big.Int)
+	// TransferFunc is the signature of a transfer function
+	TransferFunc func(StateDB, common.Address, common.Address, *big.Int)
 	// GetHashFunc returns the nth block hash in the blockchain
 	// and is used by the BLOCKHASH EVM op code.
 	GetHashFunc func(uint64) common.Hash
diff --git a/core/vm/gas.go b/core/vm/gas.go
index dd64d5f17..bba7058c7 100644
--- a/core/vm/gas.go
+++ b/core/vm/gas.go
@@ -22,6 +22,7 @@ import (
 	"github.com/ethereum/go-ethereum/params"
 )
 
+// Gas costs
 const (
 	GasQuickStep   uint64 = 2
 	GasFastestStep uint64 = 3
diff --git a/core/vm/instructions.go b/core/vm/instructions.go
index 9475322cd..1ec13ba35 100644
--- a/core/vm/instructions.go
+++ b/core/vm/instructions.go
@@ -861,7 +861,7 @@ func makeDup(size int64) executionFunc {
 // make swap instruction function
 func makeSwap(size int64) executionFunc {
 	// switch n + 1 otherwise n would be swapped with n
-	size += 1
+	size++
 	return func(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
 		stack.swap(int(size))
 		return nil, nil
diff --git a/core/vm/jump_table.go b/core/vm/jump_table.go
index 49a94d964..111a9b798 100644
--- a/core/vm/jump_table.go
+++ b/core/vm/jump_table.go
@@ -51,17 +51,17 @@ type operation struct {
 }
 
 var (
-	frontierInstructionSet       = NewFrontierInstructionSet()
-	homesteadInstructionSet      = NewHomesteadInstructionSet()
-	byzantiumInstructionSet      = NewByzantiumInstructionSet()
-	constantinopleInstructionSet = NewConstantinopleInstructionSet()
+	frontierInstructionSet       = newFrontierInstructionSet()
+	homesteadInstructionSet      = newHomesteadInstructionSet()
+	byzantiumInstructionSet      = newByzantiumInstructionSet()
+	constantinopleInstructionSet = newConstantinopleInstructionSet()
 )
 
 // NewConstantinopleInstructionSet returns the frontier, homestead
 // byzantium and contantinople instructions.
-func NewConstantinopleInstructionSet() [256]operation {
+func newConstantinopleInstructionSet() [256]operation {
 	// instructions that can be executed during the byzantium phase.
-	instructionSet := NewByzantiumInstructionSet()
+	instructionSet := newByzantiumInstructionSet()
 	instructionSet[SHL] = operation{
 		execute:       opSHL,
 		gasCost:       constGasFunc(GasFastestStep),
@@ -85,9 +85,9 @@ func NewConstantinopleInstructionSet() [256]operation {
 
 // NewByzantiumInstructionSet returns the frontier, homestead and
 // byzantium instructions.
-func NewByzantiumInstructionSet() [256]operation {
+func newByzantiumInstructionSet() [256]operation {
 	// instructions that can be executed during the homestead phase.
-	instructionSet := NewHomesteadInstructionSet()
+	instructionSet := newHomesteadInstructionSet()
 	instructionSet[STATICCALL] = operation{
 		execute:       opStaticCall,
 		gasCost:       gasStaticCall,
@@ -123,8 +123,8 @@ func NewByzantiumInstructionSet() [256]operation {
 
 // NewHomesteadInstructionSet returns the frontier and homestead
 // instructions that can be executed during the homestead phase.
-func NewHomesteadInstructionSet() [256]operation {
-	instructionSet := NewFrontierInstructionSet()
+func newHomesteadInstructionSet() [256]operation {
+	instructionSet := newFrontierInstructionSet()
 	instructionSet[DELEGATECALL] = operation{
 		execute:       opDelegateCall,
 		gasCost:       gasDelegateCall,
@@ -138,7 +138,7 @@ func NewHomesteadInstructionSet() [256]operation {
 
 // NewFrontierInstructionSet returns the frontier instructions
 // that can be executed during the frontier phase.
-func NewFrontierInstructionSet() [256]operation {
+func newFrontierInstructionSet() [256]operation {
 	return [256]operation{
 		STOP: {
 			execute:       opStop,
diff --git a/core/vm/logger.go b/core/vm/logger.go
index c32a7b404..85acb8d6d 100644
--- a/core/vm/logger.go
+++ b/core/vm/logger.go
@@ -29,8 +29,10 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 )
 
+// Storage represents a contract's storage.
 type Storage map[common.Hash]common.Hash
 
+// Copy duplicates the current storage.
 func (s Storage) Copy() Storage {
 	cpy := make(Storage)
 	for key, value := range s {
@@ -76,10 +78,12 @@ type structLogMarshaling struct {
 	ErrorString string `json:"error"`  // adds call to ErrorString() in MarshalJSON
 }
 
+// OpName formats the operand name in a human-readable format.
 func (s *StructLog) OpName() string {
 	return s.Op.String()
 }
 
+// ErrorString formats the log's error as a string.
 func (s *StructLog) ErrorString() string {
 	if s.Err != nil {
 		return s.Err.Error()
@@ -124,6 +128,7 @@ func NewStructLogger(cfg *LogConfig) *StructLogger {
 	return logger
 }
 
+// CaptureStart implements the Tracer interface to initialize the tracing operation.
 func (l *StructLogger) CaptureStart(from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) error {
 	return nil
 }
@@ -178,10 +183,13 @@ func (l *StructLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost ui
 	return nil
 }
 
+// CaptureFault implements the Tracer interface to trace an execution fault
+// while running an opcode.
 func (l *StructLogger) CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, contract *Contract, depth int, err error) error {
 	return nil
 }
 
+// CaptureEnd is called after the call finishes to finalize the tracing.
 func (l *StructLogger) CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error) error {
 	l.output = output
 	l.err = err
diff --git a/core/vm/memory.go b/core/vm/memory.go
index 43f6ff5bf..722862b1d 100644
--- a/core/vm/memory.go
+++ b/core/vm/memory.go
@@ -29,6 +29,7 @@ type Memory struct {
 	lastGasCost uint64
 }
 
+// NewMemory returns a new memory memory model.
 func NewMemory() *Memory {
 	return &Memory{}
 }
@@ -107,6 +108,7 @@ func (m *Memory) Data() []byte {
 	return m.store
 }
 
+// Print dumps the content of the memory.
 func (m *Memory) Print() {
 	fmt.Printf("### mem %d bytes ###\n", len(m.store))
 	if len(m.store) > 0 {
diff --git a/core/vm/opcodes.go b/core/vm/opcodes.go
index e3568eb00..6c12c50e5 100644
--- a/core/vm/opcodes.go
+++ b/core/vm/opcodes.go
@@ -23,6 +23,7 @@ import (
 // OpCode is an EVM opcode
 type OpCode byte
 
+// IsPush specifies if an opcode is a PUSH opcode.
 func (op OpCode) IsPush() bool {
 	switch op {
 	case PUSH1, PUSH2, PUSH3, PUSH4, PUSH5, PUSH6, PUSH7, PUSH8, PUSH9, PUSH10, PUSH11, PUSH12, PUSH13, PUSH14, PUSH15, PUSH16, PUSH17, PUSH18, PUSH19, PUSH20, PUSH21, PUSH22, PUSH23, PUSH24, PUSH25, PUSH26, PUSH27, PUSH28, PUSH29, PUSH30, PUSH31, PUSH32:
@@ -31,12 +32,13 @@ func (op OpCode) IsPush() bool {
 	return false
 }
 
+// IsStaticJump specifies if an opcode is JUMP.
 func (op OpCode) IsStaticJump() bool {
 	return op == JUMP
 }
 
+// 0x0 range - arithmetic ops.
 const (
-	// 0x0 range - arithmetic ops
 	STOP OpCode = iota
 	ADD
 	MUL
@@ -51,6 +53,7 @@ const (
 	SIGNEXTEND
 )
 
+// 0x10 range - comparison ops.
 const (
 	LT OpCode = iota + 0x10
 	GT
@@ -70,8 +73,8 @@ const (
 	SHA3 = 0x20
 )
 
+// 0x30 range - closure state.
 const (
-	// 0x30 range - closure state
 	ADDRESS OpCode = 0x30 + iota
 	BALANCE
 	ORIGIN
@@ -89,8 +92,8 @@ const (
 	RETURNDATACOPY
 )
 
+// 0x40 range - block operations.
 const (
-	// 0x40 range - block operations
 	BLOCKHASH OpCode = 0x40 + iota
 	COINBASE
 	TIMESTAMP
@@ -99,8 +102,8 @@ const (
 	GASLIMIT
 )
 
+// 0x50 range - 'storage' and execution.
 const (
-	// 0x50 range - 'storage' and execution
 	POP OpCode = 0x50 + iota
 	MLOAD
 	MSTORE
@@ -115,8 +118,8 @@ const (
 	JUMPDEST
 )
 
+// 0x60 range.
 const (
-	// 0x60 range
 	PUSH1 OpCode = 0x60 + iota
 	PUSH2
 	PUSH3
@@ -183,6 +186,7 @@ const (
 	SWAP16
 )
 
+// 0xa0 range - logging ops.
 const (
 	LOG0 OpCode = 0xa0 + iota
 	LOG1
@@ -191,15 +195,15 @@ const (
 	LOG4
 )
 
-// unofficial opcodes used for parsing
+// unofficial opcodes used for parsing.
 const (
 	PUSH OpCode = 0xb0 + iota
 	DUP
 	SWAP
 )
 
+// 0xf0 range - closures.
 const (
-	// 0xf0 range - closures
 	CREATE OpCode = 0xf0 + iota
 	CALL
 	CALLCODE
@@ -211,9 +215,9 @@ const (
 	SELFDESTRUCT = 0xff
 )
 
-// Since the opcodes aren't all in order we can't use a regular slice
+// Since the opcodes aren't all in order we can't use a regular slice.
 var opCodeToString = map[OpCode]string{
-	// 0x0 range - arithmetic ops
+	// 0x0 range - arithmetic ops.
 	STOP:       "STOP",
 	ADD:        "ADD",
 	MUL:        "MUL",
@@ -232,7 +236,7 @@ var opCodeToString = map[OpCode]string{
 	ISZERO:     "ISZERO",
 	SIGNEXTEND: "SIGNEXTEND",
 
-	// 0x10 range - bit ops
+	// 0x10 range - bit ops.
 	AND:    "AND",
 	OR:     "OR",
 	XOR:    "XOR",
@@ -243,10 +247,10 @@ var opCodeToString = map[OpCode]string{
 	ADDMOD: "ADDMOD",
 	MULMOD: "MULMOD",
 
-	// 0x20 range - crypto
+	// 0x20 range - crypto.
 	SHA3: "SHA3",
 
-	// 0x30 range - closure state
+	// 0x30 range - closure state.
 	ADDRESS:        "ADDRESS",
 	BALANCE:        "BALANCE",
 	ORIGIN:         "ORIGIN",
@@ -263,7 +267,7 @@ var opCodeToString = map[OpCode]string{
 	RETURNDATASIZE: "RETURNDATASIZE",
 	RETURNDATACOPY: "RETURNDATACOPY",
 
-	// 0x40 range - block operations
+	// 0x40 range - block operations.
 	BLOCKHASH:  "BLOCKHASH",
 	COINBASE:   "COINBASE",
 	TIMESTAMP:  "TIMESTAMP",
@@ -271,7 +275,7 @@ var opCodeToString = map[OpCode]string{
 	DIFFICULTY: "DIFFICULTY",
 	GASLIMIT:   "GASLIMIT",
 
-	// 0x50 range - 'storage' and execution
+	// 0x50 range - 'storage' and execution.
 	POP: "POP",
 	//DUP:     "DUP",
 	//SWAP:    "SWAP",
@@ -287,7 +291,7 @@ var opCodeToString = map[OpCode]string{
 	GAS:      "GAS",
 	JUMPDEST: "JUMPDEST",
 
-	// 0x60 range - push
+	// 0x60 range - push.
 	PUSH1:  "PUSH1",
 	PUSH2:  "PUSH2",
 	PUSH3:  "PUSH3",
@@ -360,7 +364,7 @@ var opCodeToString = map[OpCode]string{
 	LOG3:   "LOG3",
 	LOG4:   "LOG4",
 
-	// 0xf0 range
+	// 0xf0 range.
 	CREATE:       "CREATE",
 	CALL:         "CALL",
 	RETURN:       "RETURN",
@@ -524,6 +528,7 @@ var stringToOp = map[string]OpCode{
 	"SELFDESTRUCT":   SELFDESTRUCT,
 }
 
+// StringToOp finds the opcode whose name is stored in `str`.
 func StringToOp(str string) OpCode {
 	return stringToOp[str]
 }
diff --git a/core/vm/stack.go b/core/vm/stack.go
index 9c10d50ad..4c1b9e803 100644
--- a/core/vm/stack.go
+++ b/core/vm/stack.go
@@ -21,7 +21,7 @@ import (
 	"math/big"
 )
 
-// stack is an object for basic stack operations. Items popped to the stack are
+// Stack is an object for basic stack operations. Items popped to the stack are
 // expected to be changed and modified. stack does not take care of adding newly
 // initialised objects.
 type Stack struct {
@@ -32,6 +32,7 @@ func newstack() *Stack {
 	return &Stack{data: make([]*big.Int, 0, 1024)}
 }
 
+// Data returns the underlying big.Int array.
 func (st *Stack) Data() []*big.Int {
 	return st.data
 }
@@ -80,6 +81,7 @@ func (st *Stack) require(n int) error {
 	return nil
 }
 
+// Print dumps the content of the stack
 func (st *Stack) Print() {
 	fmt.Println("### stack ###")
 	if len(st.data) > 0 {