core/vm: clear linter warnings

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")

core/vm/evm.go

@@ -31,7 +31,9 @@ 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 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.

core/vm/gas.go

@@ -22,6 +22,7 @@ import (
 	"github.com/ethereum/go-ethereum/params"
 )
 
+// Gas costs
 const (
 	GasQuickStep   uint64 = 2
 	GasFastestStep uint64 = 3

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

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,

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
 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 logs the start of a contract
 func (l *StructLogger) CaptureStart(from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) error {
 	return nil
 }
@@ -178,10 +183,12 @@ func (l *StructLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost ui
 	return nil
 }
 
+// CaptureFault logs a fault in the execution
 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 logs the end of a contract
 func (l *StructLogger) CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error) error {
 	l.output = output
 	l.err = err

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 shows the content of the memory
 func (m *Memory) Print() {
 	fmt.Printf("### mem %d bytes ###\n", len(m.store))
 	if len(m.store) > 0 {

core/vm/noop.go

@@ -23,48 +23,105 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 )
 
+// NoopCanTransfer dummy function
 func NoopCanTransfer(db StateDB, from common.Address, balance *big.Int) bool {
 	return true
 }
+
+// NoopTransfer dummy function
 func NoopTransfer(db StateDB, from, to common.Address, amount *big.Int) {}
 
+// NoopEVMCallContext represents the EVM's call context
 type NoopEVMCallContext struct{}
 
+// Call dummy function
 func (NoopEVMCallContext) Call(caller ContractRef, addr common.Address, data []byte, gas, value *big.Int) ([]byte, error) {
 	return nil, nil
 }
+
+// CallCode dummy function
 func (NoopEVMCallContext) CallCode(caller ContractRef, addr common.Address, data []byte, gas, value *big.Int) ([]byte, error) {
 	return nil, nil
 }
+
+// Create dummy function
 func (NoopEVMCallContext) Create(caller ContractRef, data []byte, gas, value *big.Int) ([]byte, common.Address, error) {
 	return nil, common.Address{}, nil
 }
+
+// DelegateCall dummy function
 func (NoopEVMCallContext) DelegateCall(me ContractRef, addr common.Address, data []byte, gas *big.Int) ([]byte, error) {
 	return nil, nil
 }
 
+// NoopStateDB is an dummy state database
 type NoopStateDB struct{}
 
+// CreateAccount dummy method
 func (NoopStateDB) CreateAccount(common.Address) {}
+
+// SubBalance dummy method
 func (NoopStateDB) SubBalance(common.Address, *big.Int) {}
+
+// AddBalance dummy method
 func (NoopStateDB) AddBalance(common.Address, *big.Int) {}
+
+// GetBalance dummy method
 func (NoopStateDB) GetBalance(common.Address) *big.Int { return nil }
+
+// GetNonce dummy method
 func (NoopStateDB) GetNonce(common.Address) uint64 { return 0 }
+
+// SetNonce dummy method
 func (NoopStateDB) SetNonce(common.Address, uint64) {}
+
+// GetCodeHash dummy method
 func (NoopStateDB) GetCodeHash(common.Address) common.Hash { return common.Hash{} }
+
+// GetCode dummy method
 func (NoopStateDB) GetCode(common.Address) []byte { return nil }
+
+// SetCode dummy method
 func (NoopStateDB) SetCode(common.Address, []byte) {}
+
+// GetCodeSize dummy method
 func (NoopStateDB) GetCodeSize(common.Address) int { return 0 }
+
+// AddRefund dummy method
 func (NoopStateDB) AddRefund(uint64) {}
+
+// GetRefund dummy method
 func (NoopStateDB) GetRefund() uint64 { return 0 }
+
+// GetState dummy method
 func (NoopStateDB) GetState(common.Address, common.Hash) common.Hash { return common.Hash{} }
+
+// SetState dummy method
 func (NoopStateDB) SetState(common.Address, common.Hash, common.Hash) {}
+
+// Suicide dummy method
 func (NoopStateDB) Suicide(common.Address) bool { return false }
+
+// HasSuicided dummy method
 func (NoopStateDB) HasSuicided(common.Address) bool { return false }
+
+// Exist dummy method
 func (NoopStateDB) Exist(common.Address) bool { return false }
+
+// Empty dummy method
 func (NoopStateDB) Empty(common.Address) bool { return false }
+
+// RevertToSnapshot dummy method
 func (NoopStateDB) RevertToSnapshot(int) {}
+
+// Snapshot dummy method
 func (NoopStateDB) Snapshot() int { return 0 }
+
+// AddLog dummy method
 func (NoopStateDB) AddLog(*types.Log) {}
+
+// AddPreimage dummy method
 func (NoopStateDB) AddPreimage(common.Hash, []byte) {}
+
+// ForEachStorage dummy method
 func (NoopStateDB) ForEachStorage(common.Address, func(common.Hash, common.Hash) bool) {}

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
@@ -198,8 +202,8 @@ const (
 	SWAP
 )
 
+// 0xf0 range - closures
 const (
-	// 0xf0 range - closures
 	CREATE OpCode = 0xf0 + iota
 	CALL
 	CALLCODE
@@ -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]
 }

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 displays the content of the stack
 func (st *Stack) Print() {
 	fmt.Println("### stack ###")
 	if len(st.data) > 0 {