Merge pull request #14981 from karalabe/metropolis-returndata

core/vm: implement RETURNDATA metropolis opcodes

core/vm/evm.go

@@ -261,9 +261,9 @@ func (evm *EVM) StaticCall(caller ContractRef, addr common.Address, input []byte
 	// Make sure the readonly is only set if we aren't in readonly yet
 	// this makes also sure that the readonly flag isn't removed for
 	// child calls.
-	if !evm.interpreter.readonly {
+	if !evm.interpreter.readOnly {
-		evm.interpreter.readonly = true
+		evm.interpreter.readOnly = true
-		defer func() { evm.interpreter.readonly = false }()
+		defer func() { evm.interpreter.readOnly = false }()
 	}
 
 	var (

core/vm/gas_table.go

@@ -65,7 +65,33 @@ func constGasFunc(gas uint64) gasFunc {
 	}
 }
 
-func gasCalldataCopy(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
+func gasCallDataCopy(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
+	gas, err := memoryGasCost(mem, memorySize)
+	if err != nil {
+		return 0, err
+	}
+
+	var overflow bool
+	if gas, overflow = math.SafeAdd(gas, GasFastestStep); overflow {
+		return 0, errGasUintOverflow
+	}
+
+	words, overflow := bigUint64(stack.Back(2))
+	if overflow {
+		return 0, errGasUintOverflow
+	}
+
+	if words, overflow = math.SafeMul(toWordSize(words), params.CopyGas); overflow {
+		return 0, errGasUintOverflow
+	}
+
+	if gas, overflow = math.SafeAdd(gas, words); overflow {
+		return 0, errGasUintOverflow
+	}
+	return gas, nil
+}
+
+func gasReturnDataCopy(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
 	gas, err := memoryGasCost(mem, memorySize)
 	if err != nil {
 		return 0, err

core/vm/instructions.go

@@ -31,6 +31,7 @@ import (
 var (
 	bigZero                  = new(big.Int)
 	errWriteProtection       = errors.New("evm: write protection")
+	errReturnDataOutOfBounds = errors.New("evm: return data out of bounds")
 )
 
 func opAdd(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
@@ -242,6 +243,7 @@ func opAnd(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stac
 	evm.interpreter.intPool.put(y)
 	return nil, nil
 }
+
 func opOr(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
 	x, y := stack.pop(), stack.pop()
 	stack.push(x.Or(x, y))
@@ -249,6 +251,7 @@ func opOr(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack
 	evm.interpreter.intPool.put(y)
 	return nil, nil
 }
+
 func opXor(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
 	x, y := stack.pop(), stack.pop()
 	stack.push(x.Xor(x, y))
@@ -268,6 +271,7 @@ func opByte(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Sta
 	evm.interpreter.intPool.put(th)
 	return nil, nil
 }
+
 func opAddmod(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
 	x, y, z := stack.pop(), stack.pop(), stack.pop()
 	if z.Cmp(bigZero) > 0 {
@@ -281,6 +285,7 @@ func opAddmod(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *S
 	evm.interpreter.intPool.put(y, z)
 	return nil, nil
 }
+
 func opMulmod(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
 	x, y, z := stack.pop(), stack.pop(), stack.pop()
 	if z.Cmp(bigZero) > 0 {
@@ -338,25 +343,47 @@ func opCallValue(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack
 	return nil, nil
 }
 
-func opCalldataLoad(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+func opCallDataLoad(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
 	stack.push(new(big.Int).SetBytes(getDataBig(contract.Input, stack.pop(), big32)))
 	return nil, nil
 }
 
-func opCalldataSize(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+func opCallDataSize(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
 	stack.push(evm.interpreter.intPool.get().SetInt64(int64(len(contract.Input))))
 	return nil, nil
 }
 
-func opCalldataCopy(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+func opCallDataCopy(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
 	var (
-		mOff = stack.pop()
+		memOffset  = stack.pop()
-		cOff = stack.pop()
+		dataOffset = stack.pop()
-		l    = stack.pop()
+		length     = stack.pop()
 	)
-	memory.Set(mOff.Uint64(), l.Uint64(), getDataBig(contract.Input, cOff, l))
+	memory.Set(memOffset.Uint64(), length.Uint64(), getDataBig(contract.Input, dataOffset, length))
+
+	evm.interpreter.intPool.put(memOffset, dataOffset, length)
+	return nil, nil
+}
+
+func opReturnDataSize(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+	stack.push(evm.interpreter.intPool.get().SetUint64(uint64(len(evm.interpreter.returnData))))
+	return nil, nil
+}
+
+func opReturnDataCopy(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+	var (
+		memOffset  = stack.pop()
+		dataOffset = stack.pop()
+		length     = stack.pop()
+	)
+	defer evm.interpreter.intPool.put(memOffset, dataOffset, length)
+
+	end := new(big.Int).Add(dataOffset, length)
+	if end.BitLen() > 64 || uint64(len(evm.interpreter.returnData)) < end.Uint64() {
+		return nil, errReturnDataOutOfBounds
+	}
+	memory.Set(memOffset.Uint64(), length.Uint64(), evm.interpreter.returnData[dataOffset.Uint64():end.Uint64()])
 
-	evm.interpreter.intPool.put(mOff, cOff, l)
 	return nil, nil
 }
 
@@ -378,31 +405,28 @@ func opCodeSize(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack
 
 func opCodeCopy(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
 	var (
-		mOff = stack.pop()
+		memOffset  = stack.pop()
-		cOff = stack.pop()
+		codeOffset = stack.pop()
-		l    = stack.pop()
+		length     = stack.pop()
 	)
-	codeCopy := getDataBig(contract.Code, cOff, l)
+	codeCopy := getDataBig(contract.Code, codeOffset, length)
+	memory.Set(memOffset.Uint64(), length.Uint64(), codeCopy)
 
-	memory.Set(mOff.Uint64(), l.Uint64(), codeCopy)
+	evm.interpreter.intPool.put(memOffset, codeOffset, length)
-
-	evm.interpreter.intPool.put(mOff, cOff, l)
 	return nil, nil
 }
 
 func opExtCodeCopy(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
 	var (
 		addr       = common.BigToAddress(stack.pop())
-		mOff = stack.pop()
+		memOffset  = stack.pop()
-		cOff = stack.pop()
+		codeOffset = stack.pop()
-		l    = stack.pop()
+		length     = stack.pop()
 	)
-	codeCopy := getDataBig(evm.StateDB.GetCode(addr), cOff, l)
+	codeCopy := getDataBig(evm.StateDB.GetCode(addr), codeOffset, length)
-
+	memory.Set(memOffset.Uint64(), length.Uint64(), codeCopy)
-	memory.Set(mOff.Uint64(), l.Uint64(), codeCopy)
-
-	evm.interpreter.intPool.put(mOff, cOff, l)
 
+	evm.interpreter.intPool.put(memOffset, codeOffset, length)
 	return nil, nil
 }
 
@@ -507,6 +531,7 @@ func opJump(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Sta
 	evm.interpreter.intPool.put(pos)
 	return nil, nil
 }
+
 func opJumpi(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
 	pos, cond := stack.pop(), stack.pop()
 	if cond.Sign() != 0 {
@@ -522,6 +547,7 @@ func opJumpi(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *St
 	evm.interpreter.intPool.put(pos, cond)
 	return nil, nil
 }
+
 func opJumpdest(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
 	return nil, nil
 }

core/vm/interpreter.go

@@ -59,7 +59,8 @@ type Interpreter struct {
 	gasTable params.GasTable
 	intPool  *intPool
 
-	readonly bool
+	readOnly   bool   // Whether to throw on stateful modifications
+	returnData []byte // Last CALL's return data for subsequent reuse
 }
 
 // NewInterpreter returns a new instance of the Interpreter.
@@ -88,7 +89,7 @@ func NewInterpreter(evm *EVM, cfg Config) *Interpreter {
 
 func (in *Interpreter) enforceRestrictions(op OpCode, operation operation, stack *Stack) error {
 	if in.evm.chainRules.IsMetropolis {
-		if in.readonly {
+		if in.readOnly {
 			// If the interpreter is operating in readonly mode, make sure no
 			// state-modifying operation is performed. The 3rd stack item
 			// for a call operation is the value. Transfering value from one
@@ -113,6 +114,10 @@ func (in *Interpreter) Run(snapshot int, contract *Contract, input []byte) (ret
 	in.evm.depth++
 	defer func() { in.evm.depth-- }()
 
+	// Reset the previous call's return data. It's unimportant to preserve the old buffer
+	// as every returning call will return new data anyway.
+	in.returnData = nil
+
 	// Don't bother with the execution if there's no code.
 	if len(contract.Code) == 0 {
 		return nil, nil
@@ -213,10 +218,10 @@ func (in *Interpreter) Run(snapshot int, contract *Contract, input []byte) (ret
 		case !operation.jumps:
 			pc++
 		}
-		// if the operation returned a value make sure that is also set
+		// if the operation clears the return data (e.g. it has returning data)
-		// the last return data.
+		// set the last return to the result of the operation.
-		if res != nil {
+		if operation.returns {
-			mem.lastReturn = ret
+			in.returnData = res
 		}
 	}
 	return nil, nil

core/vm/jump_table.go

@@ -53,6 +53,8 @@ type operation struct {
 	valid bool
 	// reverts determined whether the operation reverts state
 	reverts bool
+	// returns determines whether the opertions sets the return data
+	returns bool
 }
 
 var (
@@ -72,6 +74,20 @@ func NewMetropolisInstructionSet() [256]operation {
 		validateStack: makeStackFunc(6, 1),
 		memorySize:    memoryStaticCall,
 		valid:         true,
+		returns:       true,
+	}
+	instructionSet[RETURNDATASIZE] = operation{
+		execute:       opReturnDataSize,
+		gasCost:       constGasFunc(GasQuickStep),
+		validateStack: makeStackFunc(0, 1),
+		valid:         true,
+	}
+	instructionSet[RETURNDATACOPY] = operation{
+		execute:       opReturnDataCopy,
+		gasCost:       gasReturnDataCopy,
+		validateStack: makeStackFunc(3, 0),
+		memorySize:    memoryReturnDataCopy,
+		valid:         true,
 	}
 	return instructionSet
 }
@@ -86,6 +102,7 @@ func NewHomesteadInstructionSet() [256]operation {
 		validateStack: makeStackFunc(6, 1),
 		memorySize:    memoryDelegateCall,
 		valid:         true,
+		returns:       true,
 	}
 	return instructionSet
 }
@@ -271,22 +288,22 @@ func NewFrontierInstructionSet() [256]operation {
 			valid:         true,
 		},
 		CALLDATALOAD: {
-			execute:       opCalldataLoad,
+			execute:       opCallDataLoad,
 			gasCost:       constGasFunc(GasFastestStep),
 			validateStack: makeStackFunc(1, 1),
 			valid:         true,
 		},
 		CALLDATASIZE: {
-			execute:       opCalldataSize,
+			execute:       opCallDataSize,
 			gasCost:       constGasFunc(GasQuickStep),
 			validateStack: makeStackFunc(0, 1),
 			valid:         true,
 		},
 		CALLDATACOPY: {
-			execute:       opCalldataCopy,
+			execute:       opCallDataCopy,
-			gasCost:       gasCalldataCopy,
+			gasCost:       gasCallDataCopy,
 			validateStack: makeStackFunc(3, 0),
-			memorySize:    memoryCalldataCopy,
+			memorySize:    memoryCallDataCopy,
 			valid:         true,
 		},
 		CODESIZE: {
@@ -867,6 +884,7 @@ func NewFrontierInstructionSet() [256]operation {
 			memorySize:    memoryCreate,
 			valid:         true,
 			writes:        true,
+			returns:       true,
 		},
 		CALL: {
 			execute:       opCall,
@@ -874,6 +892,7 @@ func NewFrontierInstructionSet() [256]operation {
 			validateStack: makeStackFunc(7, 1),
 			memorySize:    memoryCall,
 			valid:         true,
+			returns:       true,
 		},
 		CALLCODE: {
 			execute:       opCallCode,
@@ -881,6 +900,7 @@ func NewFrontierInstructionSet() [256]operation {
 			validateStack: makeStackFunc(7, 1),
 			memorySize:    memoryCall,
 			valid:         true,
+			returns:       true,
 		},
 		RETURN: {
 			execute:       opReturn,

core/vm/memory.go

@@ -22,7 +22,6 @@ import "fmt"
 type Memory struct {
 	store       []byte
 	lastGasCost uint64
-	lastReturn  []byte
 }
 
 func NewMemory() *Memory {

core/vm/memory_table.go

@@ -26,7 +26,11 @@ func memorySha3(stack *Stack) *big.Int {
 	return calcMemSize(stack.Back(0), stack.Back(1))
 }
 
-func memoryCalldataCopy(stack *Stack) *big.Int {
+func memoryCallDataCopy(stack *Stack) *big.Int {
+	return calcMemSize(stack.Back(0), stack.Back(2))
+}
+
+func memoryReturnDataCopy(stack *Stack) *big.Int {
 	return calcMemSize(stack.Back(0), stack.Back(2))
 }
 

core/vm/opcodes.go

@@ -82,10 +82,11 @@ const (
 	GASPRICE
 	EXTCODESIZE
 	EXTCODECOPY
+	RETURNDATASIZE
+	RETURNDATACOPY
 )
 
 const (
-
 	// 0x40 range - block operations
 	BLOCKHASH OpCode = 0x40 + iota
 	COINBASE
@@ -250,6 +251,10 @@ var opCodeToString = map[OpCode]string{
 	CODESIZE:       "CODESIZE",
 	CODECOPY:       "CODECOPY",
 	GASPRICE:       "GASPRICE",
+	EXTCODESIZE:    "EXTCODESIZE",
+	EXTCODECOPY:    "EXTCODECOPY",
+	RETURNDATASIZE: "RETURNDATASIZE",
+	RETURNDATACOPY: "RETURNDATACOPY",
 
 	// 0x40 range - block operations
 	BLOCKHASH:  "BLOCKHASH",
@@ -258,8 +263,6 @@ var opCodeToString = map[OpCode]string{
 	NUMBER:     "NUMBER",
 	DIFFICULTY: "DIFFICULTY",
 	GASLIMIT:   "GASLIMIT",
-	EXTCODESIZE: "EXTCODESIZE",
-	EXTCODECOPY: "EXTCODECOPY",
 
 	// 0x50 range - 'storage' and execution
 	POP: "POP",
@@ -411,14 +414,16 @@ var stringToOp = map[string]OpCode{
 	"CODESIZE":       CODESIZE,
 	"CODECOPY":       CODECOPY,
 	"GASPRICE":       GASPRICE,
+	"EXTCODESIZE":    EXTCODESIZE,
+	"EXTCODECOPY":    EXTCODECOPY,
+	"RETURNDATASIZE": RETURNDATASIZE,
+	"RETURNDATACOPY": RETURNDATACOPY,
 	"BLOCKHASH":      BLOCKHASH,
 	"COINBASE":       COINBASE,
 	"TIMESTAMP":      TIMESTAMP,
 	"NUMBER":         NUMBER,
 	"DIFFICULTY":     DIFFICULTY,
 	"GASLIMIT":       GASLIMIT,
-	"EXTCODESIZE":  EXTCODESIZE,
-	"EXTCODECOPY":  EXTCODECOPY,
 	"POP":            POP,
 	"MLOAD":          MLOAD,
 	"MSTORE":         MSTORE,

tests/testdata

@@ -1 +1 @@
-Subproject commit 815151e4cea4e73328f8586b4e61c3d7e1e9e543
+Subproject commit 85f6d7cc01b6bd04e071f5ba579fc675cfd2043b