eth/tracers, core: use scopecontext in tracers, provide statedb in capturestart (#22333)

Fixes the CaptureStart api to include the EVM, thus being able to set the statedb early on. This pr also exposes the struct we used internally in the interpreter to encapsulate the contract, mem, stack, rstack, so we pass it as a single struct to the tracer, and removes the error returns on the capture methods.

core/vm/eips.go

@@ -76,9 +76,9 @@ func enable1884(jt *JumpTable) {
 	}
 }
 
-func opSelfBalance(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	balance, _ := uint256.FromBig(interpreter.evm.StateDB.GetBalance(callContext.contract.Address()))
-	callContext.stack.push(balance)
+func opSelfBalance(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	balance, _ := uint256.FromBig(interpreter.evm.StateDB.GetBalance(scope.Contract.Address()))
+	scope.Stack.push(balance)
 	return nil, nil
 }
 
@@ -95,9 +95,9 @@ func enable1344(jt *JumpTable) {
 }
 
 // opChainID implements CHAINID opcode
-func opChainID(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+func opChainID(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
 	chainId, _ := uint256.FromBig(interpreter.evm.chainConfig.ChainID)
-	callContext.stack.push(chainId)
+	scope.Stack.push(chainId)
 	return nil, nil
 }
 

core/vm/evm.go

@@ -239,7 +239,7 @@ func (evm *EVM) Call(caller ContractRef, addr common.Address, input []byte, gas
 		if !isPrecompile && evm.chainRules.IsEIP158 && value.Sign() == 0 {
 			// Calling a non existing account, don't do anything, but ping the tracer
 			if evm.vmConfig.Debug && evm.depth == 0 {
-				evm.vmConfig.Tracer.CaptureStart(caller.Address(), addr, false, input, gas, value)
+				evm.vmConfig.Tracer.CaptureStart(evm, caller.Address(), addr, false, input, gas, value)
 				evm.vmConfig.Tracer.CaptureEnd(ret, 0, 0, nil)
 			}
 			return nil, gas, nil
@@ -250,7 +250,7 @@ func (evm *EVM) Call(caller ContractRef, addr common.Address, input []byte, gas
 
 	// Capture the tracer start/end events in debug mode
 	if evm.vmConfig.Debug && evm.depth == 0 {
-		evm.vmConfig.Tracer.CaptureStart(caller.Address(), addr, false, input, gas, value)
+		evm.vmConfig.Tracer.CaptureStart(evm, caller.Address(), addr, false, input, gas, value)
 		defer func(startGas uint64, startTime time.Time) { // Lazy evaluation of the parameters
 			evm.vmConfig.Tracer.CaptureEnd(ret, startGas-gas, time.Since(startTime), err)
 		}(gas, time.Now())
@@ -472,7 +472,7 @@ func (evm *EVM) create(caller ContractRef, codeAndHash *codeAndHash, gas uint64,
 	}
 
 	if evm.vmConfig.Debug && evm.depth == 0 {
-		evm.vmConfig.Tracer.CaptureStart(caller.Address(), address, true, codeAndHash.code, gas, value)
+		evm.vmConfig.Tracer.CaptureStart(evm, caller.Address(), address, true, codeAndHash.code, gas, value)
 	}
 	start := time.Now()
 

core/vm/instructions.go

@@ -24,68 +24,68 @@ import (
 	"golang.org/x/crypto/sha3"
 )
 
-func opAdd(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	x, y := callContext.stack.pop(), callContext.stack.peek()
+func opAdd(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	x, y := scope.Stack.pop(), scope.Stack.peek()
 	y.Add(&x, y)
 	return nil, nil
 }
 
-func opSub(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	x, y := callContext.stack.pop(), callContext.stack.peek()
+func opSub(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	x, y := scope.Stack.pop(), scope.Stack.peek()
 	y.Sub(&x, y)
 	return nil, nil
 }
 
-func opMul(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	x, y := callContext.stack.pop(), callContext.stack.peek()
+func opMul(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	x, y := scope.Stack.pop(), scope.Stack.peek()
 	y.Mul(&x, y)
 	return nil, nil
 }
 
-func opDiv(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	x, y := callContext.stack.pop(), callContext.stack.peek()
+func opDiv(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	x, y := scope.Stack.pop(), scope.Stack.peek()
 	y.Div(&x, y)
 	return nil, nil
 }
 
-func opSdiv(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	x, y := callContext.stack.pop(), callContext.stack.peek()
+func opSdiv(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	x, y := scope.Stack.pop(), scope.Stack.peek()
 	y.SDiv(&x, y)
 	return nil, nil
 }
 
-func opMod(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	x, y := callContext.stack.pop(), callContext.stack.peek()
+func opMod(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	x, y := scope.Stack.pop(), scope.Stack.peek()
 	y.Mod(&x, y)
 	return nil, nil
 }
 
-func opSmod(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	x, y := callContext.stack.pop(), callContext.stack.peek()
+func opSmod(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	x, y := scope.Stack.pop(), scope.Stack.peek()
 	y.SMod(&x, y)
 	return nil, nil
 }
 
-func opExp(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	base, exponent := callContext.stack.pop(), callContext.stack.peek()
+func opExp(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	base, exponent := scope.Stack.pop(), scope.Stack.peek()
 	exponent.Exp(&base, exponent)
 	return nil, nil
 }
 
-func opSignExtend(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	back, num := callContext.stack.pop(), callContext.stack.peek()
+func opSignExtend(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	back, num := scope.Stack.pop(), scope.Stack.peek()
 	num.ExtendSign(num, &back)
 	return nil, nil
 }
 
-func opNot(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	x := callContext.stack.peek()
+func opNot(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	x := scope.Stack.peek()
 	x.Not(x)
 	return nil, nil
 }
 
-func opLt(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	x, y := callContext.stack.pop(), callContext.stack.peek()
+func opLt(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	x, y := scope.Stack.pop(), scope.Stack.peek()
 	if x.Lt(y) {
 		y.SetOne()
 	} else {
@@ -94,8 +94,8 @@ func opLt(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte
 	return nil, nil
 }
 
-func opGt(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	x, y := callContext.stack.pop(), callContext.stack.peek()
+func opGt(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	x, y := scope.Stack.pop(), scope.Stack.peek()
 	if x.Gt(y) {
 		y.SetOne()
 	} else {
@@ -104,8 +104,8 @@ func opGt(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte
 	return nil, nil
 }
 
-func opSlt(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	x, y := callContext.stack.pop(), callContext.stack.peek()
+func opSlt(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	x, y := scope.Stack.pop(), scope.Stack.peek()
 	if x.Slt(y) {
 		y.SetOne()
 	} else {
@@ -114,8 +114,8 @@ func opSlt(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byt
 	return nil, nil
 }
 
-func opSgt(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	x, y := callContext.stack.pop(), callContext.stack.peek()
+func opSgt(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	x, y := scope.Stack.pop(), scope.Stack.peek()
 	if x.Sgt(y) {
 		y.SetOne()
 	} else {
@@ -124,8 +124,8 @@ func opSgt(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byt
 	return nil, nil
 }
 
-func opEq(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	x, y := callContext.stack.pop(), callContext.stack.peek()
+func opEq(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	x, y := scope.Stack.pop(), scope.Stack.peek()
 	if x.Eq(y) {
 		y.SetOne()
 	} else {
@@ -134,8 +134,8 @@ func opEq(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte
 	return nil, nil
 }
 
-func opIszero(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	x := callContext.stack.peek()
+func opIszero(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	x := scope.Stack.peek()
 	if x.IsZero() {
 		x.SetOne()
 	} else {
@@ -144,32 +144,32 @@ func opIszero(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]
 	return nil, nil
 }
 
-func opAnd(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	x, y := callContext.stack.pop(), callContext.stack.peek()
+func opAnd(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	x, y := scope.Stack.pop(), scope.Stack.peek()
 	y.And(&x, y)
 	return nil, nil
 }
 
-func opOr(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	x, y := callContext.stack.pop(), callContext.stack.peek()
+func opOr(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	x, y := scope.Stack.pop(), scope.Stack.peek()
 	y.Or(&x, y)
 	return nil, nil
 }
 
-func opXor(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	x, y := callContext.stack.pop(), callContext.stack.peek()
+func opXor(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	x, y := scope.Stack.pop(), scope.Stack.peek()
 	y.Xor(&x, y)
 	return nil, nil
 }
 
-func opByte(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	th, val := callContext.stack.pop(), callContext.stack.peek()
+func opByte(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	th, val := scope.Stack.pop(), scope.Stack.peek()
 	val.Byte(&th)
 	return nil, nil
 }
 
-func opAddmod(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	x, y, z := callContext.stack.pop(), callContext.stack.pop(), callContext.stack.peek()
+func opAddmod(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	x, y, z := scope.Stack.pop(), scope.Stack.pop(), scope.Stack.peek()
 	if z.IsZero() {
 		z.Clear()
 	} else {
@@ -178,8 +178,8 @@ func opAddmod(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]
 	return nil, nil
 }
 
-func opMulmod(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	x, y, z := callContext.stack.pop(), callContext.stack.pop(), callContext.stack.peek()
+func opMulmod(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	x, y, z := scope.Stack.pop(), scope.Stack.pop(), scope.Stack.peek()
 	z.MulMod(&x, &y, z)
 	return nil, nil
 }
@@ -187,9 +187,9 @@ func opMulmod(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]
 // opSHL implements Shift Left
 // The SHL instruction (shift left) pops 2 values from the stack, first arg1 and then arg2,
 // and pushes on the stack arg2 shifted to the left by arg1 number of bits.
-func opSHL(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+func opSHL(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
 	// Note, second operand is left in the stack; accumulate result into it, and no need to push it afterwards
-	shift, value := callContext.stack.pop(), callContext.stack.peek()
+	shift, value := scope.Stack.pop(), scope.Stack.peek()
 	if shift.LtUint64(256) {
 		value.Lsh(value, uint(shift.Uint64()))
 	} else {
@@ -201,9 +201,9 @@ func opSHL(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byt
 // opSHR implements Logical Shift Right
 // The SHR instruction (logical shift right) pops 2 values from the stack, first arg1 and then arg2,
 // and pushes on the stack arg2 shifted to the right by arg1 number of bits with zero fill.
-func opSHR(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+func opSHR(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
 	// Note, second operand is left in the stack; accumulate result into it, and no need to push it afterwards
-	shift, value := callContext.stack.pop(), callContext.stack.peek()
+	shift, value := scope.Stack.pop(), scope.Stack.peek()
 	if shift.LtUint64(256) {
 		value.Rsh(value, uint(shift.Uint64()))
 	} else {
@@ -215,8 +215,8 @@ func opSHR(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byt
 // opSAR implements Arithmetic Shift Right
 // The SAR instruction (arithmetic shift right) pops 2 values from the stack, first arg1 and then arg2,
 // and pushes on the stack arg2 shifted to the right by arg1 number of bits with sign extension.
-func opSAR(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	shift, value := callContext.stack.pop(), callContext.stack.peek()
+func opSAR(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	shift, value := scope.Stack.pop(), scope.Stack.peek()
 	if shift.GtUint64(256) {
 		if value.Sign() >= 0 {
 			value.Clear()
@@ -231,9 +231,9 @@ func opSAR(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byt
 	return nil, nil
 }
 
-func opSha3(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	offset, size := callContext.stack.pop(), callContext.stack.peek()
-	data := callContext.memory.GetPtr(int64(offset.Uint64()), int64(size.Uint64()))
+func opSha3(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	offset, size := scope.Stack.pop(), scope.Stack.peek()
+	data := scope.Memory.GetPtr(int64(offset.Uint64()), int64(size.Uint64()))
 
 	if interpreter.hasher == nil {
 		interpreter.hasher = sha3.NewLegacyKeccak256().(keccakState)
@@ -251,37 +251,37 @@ func opSha3(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]by
 	size.SetBytes(interpreter.hasherBuf[:])
 	return nil, nil
 }
-func opAddress(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	callContext.stack.push(new(uint256.Int).SetBytes(callContext.contract.Address().Bytes()))
+func opAddress(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	scope.Stack.push(new(uint256.Int).SetBytes(scope.Contract.Address().Bytes()))
 	return nil, nil
 }
 
-func opBalance(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	slot := callContext.stack.peek()
+func opBalance(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	slot := scope.Stack.peek()
 	address := common.Address(slot.Bytes20())
 	slot.SetFromBig(interpreter.evm.StateDB.GetBalance(address))
 	return nil, nil
 }
 
-func opOrigin(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	callContext.stack.push(new(uint256.Int).SetBytes(interpreter.evm.Origin.Bytes()))
+func opOrigin(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	scope.Stack.push(new(uint256.Int).SetBytes(interpreter.evm.Origin.Bytes()))
 	return nil, nil
 }
-func opCaller(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	callContext.stack.push(new(uint256.Int).SetBytes(callContext.contract.Caller().Bytes()))
+func opCaller(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	scope.Stack.push(new(uint256.Int).SetBytes(scope.Contract.Caller().Bytes()))
 	return nil, nil
 }
 
-func opCallValue(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	v, _ := uint256.FromBig(callContext.contract.value)
-	callContext.stack.push(v)
+func opCallValue(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	v, _ := uint256.FromBig(scope.Contract.value)
+	scope.Stack.push(v)
 	return nil, nil
 }
 
-func opCallDataLoad(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	x := callContext.stack.peek()
+func opCallDataLoad(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	x := scope.Stack.peek()
 	if offset, overflow := x.Uint64WithOverflow(); !overflow {
-		data := getData(callContext.contract.Input, offset, 32)
+		data := getData(scope.Contract.Input, offset, 32)
 		x.SetBytes(data)
 	} else {
 		x.Clear()
@@ -289,16 +289,16 @@ func opCallDataLoad(pc *uint64, interpreter *EVMInterpreter, callContext *callCt
 	return nil, nil
 }
 
-func opCallDataSize(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	callContext.stack.push(new(uint256.Int).SetUint64(uint64(len(callContext.contract.Input))))
+func opCallDataSize(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	scope.Stack.push(new(uint256.Int).SetUint64(uint64(len(scope.Contract.Input))))
 	return nil, nil
 }
 
-func opCallDataCopy(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+func opCallDataCopy(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
 	var (
-		memOffset  = callContext.stack.pop()
-		dataOffset = callContext.stack.pop()
-		length     = callContext.stack.pop()
+		memOffset  = scope.Stack.pop()
+		dataOffset = scope.Stack.pop()
+		length     = scope.Stack.pop()
 	)
 	dataOffset64, overflow := dataOffset.Uint64WithOverflow()
 	if overflow {
@@ -307,21 +307,21 @@ func opCallDataCopy(pc *uint64, interpreter *EVMInterpreter, callContext *callCt
 	// These values are checked for overflow during gas cost calculation
 	memOffset64 := memOffset.Uint64()
 	length64 := length.Uint64()
-	callContext.memory.Set(memOffset64, length64, getData(callContext.contract.Input, dataOffset64, length64))
+	scope.Memory.Set(memOffset64, length64, getData(scope.Contract.Input, dataOffset64, length64))
 
 	return nil, nil
 }
 
-func opReturnDataSize(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	callContext.stack.push(new(uint256.Int).SetUint64(uint64(len(interpreter.returnData))))
+func opReturnDataSize(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	scope.Stack.push(new(uint256.Int).SetUint64(uint64(len(interpreter.returnData))))
 	return nil, nil
 }
 
-func opReturnDataCopy(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+func opReturnDataCopy(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
 	var (
-		memOffset  = callContext.stack.pop()
-		dataOffset = callContext.stack.pop()
-		length     = callContext.stack.pop()
+		memOffset  = scope.Stack.pop()
+		dataOffset = scope.Stack.pop()
+		length     = scope.Stack.pop()
 	)
 
 	offset64, overflow := dataOffset.Uint64WithOverflow()
@@ -335,42 +335,42 @@ func opReturnDataCopy(pc *uint64, interpreter *EVMInterpreter, callContext *call
 	if overflow || uint64(len(interpreter.returnData)) < end64 {
 		return nil, ErrReturnDataOutOfBounds
 	}
-	callContext.memory.Set(memOffset.Uint64(), length.Uint64(), interpreter.returnData[offset64:end64])
+	scope.Memory.Set(memOffset.Uint64(), length.Uint64(), interpreter.returnData[offset64:end64])
 	return nil, nil
 }
 
-func opExtCodeSize(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	slot := callContext.stack.peek()
+func opExtCodeSize(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	slot := scope.Stack.peek()
 	slot.SetUint64(uint64(interpreter.evm.StateDB.GetCodeSize(slot.Bytes20())))
 	return nil, nil
 }
 
-func opCodeSize(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+func opCodeSize(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
 	l := new(uint256.Int)
-	l.SetUint64(uint64(len(callContext.contract.Code)))
-	callContext.stack.push(l)
+	l.SetUint64(uint64(len(scope.Contract.Code)))
+	scope.Stack.push(l)
 	return nil, nil
 }
 
-func opCodeCopy(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+func opCodeCopy(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
 	var (
-		memOffset  = callContext.stack.pop()
-		codeOffset = callContext.stack.pop()
-		length     = callContext.stack.pop()
+		memOffset  = scope.Stack.pop()
+		codeOffset = scope.Stack.pop()
+		length     = scope.Stack.pop()
 	)
 	uint64CodeOffset, overflow := codeOffset.Uint64WithOverflow()
 	if overflow {
 		uint64CodeOffset = 0xffffffffffffffff
 	}
-	codeCopy := getData(callContext.contract.Code, uint64CodeOffset, length.Uint64())
-	callContext.memory.Set(memOffset.Uint64(), length.Uint64(), codeCopy)
+	codeCopy := getData(scope.Contract.Code, uint64CodeOffset, length.Uint64())
+	scope.Memory.Set(memOffset.Uint64(), length.Uint64(), codeCopy)
 
 	return nil, nil
 }
 
-func opExtCodeCopy(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+func opExtCodeCopy(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
 	var (
-		stack      = callContext.stack
+		stack      = scope.Stack
 		a          = stack.pop()
 		memOffset  = stack.pop()
 		codeOffset = stack.pop()
@@ -382,7 +382,7 @@ func opExtCodeCopy(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx
 	}
 	addr := common.Address(a.Bytes20())
 	codeCopy := getData(interpreter.evm.StateDB.GetCode(addr), uint64CodeOffset, length.Uint64())
-	callContext.memory.Set(memOffset.Uint64(), length.Uint64(), codeCopy)
+	scope.Memory.Set(memOffset.Uint64(), length.Uint64(), codeCopy)
 
 	return nil, nil
 }
@@ -413,8 +413,8 @@ func opExtCodeCopy(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx
 //
 //   (6) Caller tries to get the code hash for an account which is marked as deleted,
 // this account should be regarded as a non-existent account and zero should be returned.
-func opExtCodeHash(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	slot := callContext.stack.peek()
+func opExtCodeHash(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	slot := scope.Stack.peek()
 	address := common.Address(slot.Bytes20())
 	if interpreter.evm.StateDB.Empty(address) {
 		slot.Clear()
@@ -424,14 +424,14 @@ func opExtCodeHash(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx
 	return nil, nil
 }
 
-func opGasprice(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+func opGasprice(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
 	v, _ := uint256.FromBig(interpreter.evm.GasPrice)
-	callContext.stack.push(v)
+	scope.Stack.push(v)
 	return nil, nil
 }
 
-func opBlockhash(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	num := callContext.stack.peek()
+func opBlockhash(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	num := scope.Stack.peek()
 	num64, overflow := num.Uint64WithOverflow()
 	if overflow {
 		num.Clear()
@@ -452,88 +452,88 @@ func opBlockhash(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx)
 	return nil, nil
 }
 
-func opCoinbase(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	callContext.stack.push(new(uint256.Int).SetBytes(interpreter.evm.Context.Coinbase.Bytes()))
+func opCoinbase(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	scope.Stack.push(new(uint256.Int).SetBytes(interpreter.evm.Context.Coinbase.Bytes()))
 	return nil, nil
 }
 
-func opTimestamp(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+func opTimestamp(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
 	v, _ := uint256.FromBig(interpreter.evm.Context.Time)
-	callContext.stack.push(v)
+	scope.Stack.push(v)
 	return nil, nil
 }
 
-func opNumber(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+func opNumber(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
 	v, _ := uint256.FromBig(interpreter.evm.Context.BlockNumber)
-	callContext.stack.push(v)
+	scope.Stack.push(v)
 	return nil, nil
 }
 
-func opDifficulty(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+func opDifficulty(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
 	v, _ := uint256.FromBig(interpreter.evm.Context.Difficulty)
-	callContext.stack.push(v)
+	scope.Stack.push(v)
 	return nil, nil
 }
 
-func opGasLimit(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	callContext.stack.push(new(uint256.Int).SetUint64(interpreter.evm.Context.GasLimit))
+func opGasLimit(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	scope.Stack.push(new(uint256.Int).SetUint64(interpreter.evm.Context.GasLimit))
 	return nil, nil
 }
 
-func opPop(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	callContext.stack.pop()
+func opPop(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	scope.Stack.pop()
 	return nil, nil
 }
 
-func opMload(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	v := callContext.stack.peek()
+func opMload(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	v := scope.Stack.peek()
 	offset := int64(v.Uint64())
-	v.SetBytes(callContext.memory.GetPtr(offset, 32))
+	v.SetBytes(scope.Memory.GetPtr(offset, 32))
 	return nil, nil
 }
 
-func opMstore(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+func opMstore(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
 	// pop value of the stack
-	mStart, val := callContext.stack.pop(), callContext.stack.pop()
-	callContext.memory.Set32(mStart.Uint64(), &val)
+	mStart, val := scope.Stack.pop(), scope.Stack.pop()
+	scope.Memory.Set32(mStart.Uint64(), &val)
 	return nil, nil
 }
 
-func opMstore8(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	off, val := callContext.stack.pop(), callContext.stack.pop()
-	callContext.memory.store[off.Uint64()] = byte(val.Uint64())
+func opMstore8(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	off, val := scope.Stack.pop(), scope.Stack.pop()
+	scope.Memory.store[off.Uint64()] = byte(val.Uint64())
 	return nil, nil
 }
 
-func opSload(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	loc := callContext.stack.peek()
+func opSload(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	loc := scope.Stack.peek()
 	hash := common.Hash(loc.Bytes32())
-	val := interpreter.evm.StateDB.GetState(callContext.contract.Address(), hash)
+	val := interpreter.evm.StateDB.GetState(scope.Contract.Address(), hash)
 	loc.SetBytes(val.Bytes())
 	return nil, nil
 }
 
-func opSstore(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	loc := callContext.stack.pop()
-	val := callContext.stack.pop()
-	interpreter.evm.StateDB.SetState(callContext.contract.Address(),
+func opSstore(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	loc := scope.Stack.pop()
+	val := scope.Stack.pop()
+	interpreter.evm.StateDB.SetState(scope.Contract.Address(),
 		loc.Bytes32(), val.Bytes32())
 	return nil, nil
 }
 
-func opJump(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	pos := callContext.stack.pop()
-	if !callContext.contract.validJumpdest(&pos) {
+func opJump(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	pos := scope.Stack.pop()
+	if !scope.Contract.validJumpdest(&pos) {
 		return nil, ErrInvalidJump
 	}
 	*pc = pos.Uint64()
 	return nil, nil
 }
 
-func opJumpi(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	pos, cond := callContext.stack.pop(), callContext.stack.pop()
+func opJumpi(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	pos, cond := scope.Stack.pop(), scope.Stack.pop()
 	if !cond.IsZero() {
-		if !callContext.contract.validJumpdest(&pos) {
+		if !scope.Contract.validJumpdest(&pos) {
 			return nil, ErrInvalidJump
 		}
 		*pc = pos.Uint64()
@@ -543,31 +543,31 @@ func opJumpi(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]b
 	return nil, nil
 }
 
-func opJumpdest(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+func opJumpdest(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
 	return nil, nil
 }
 
-func opPc(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	callContext.stack.push(new(uint256.Int).SetUint64(*pc))
+func opPc(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	scope.Stack.push(new(uint256.Int).SetUint64(*pc))
 	return nil, nil
 }
 
-func opMsize(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	callContext.stack.push(new(uint256.Int).SetUint64(uint64(callContext.memory.Len())))
+func opMsize(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	scope.Stack.push(new(uint256.Int).SetUint64(uint64(scope.Memory.Len())))
 	return nil, nil
 }
 
-func opGas(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	callContext.stack.push(new(uint256.Int).SetUint64(callContext.contract.Gas))
+func opGas(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	scope.Stack.push(new(uint256.Int).SetUint64(scope.Contract.Gas))
 	return nil, nil
 }
 
-func opCreate(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+func opCreate(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
 	var (
-		value        = callContext.stack.pop()
-		offset, size = callContext.stack.pop(), callContext.stack.pop()
-		input        = callContext.memory.GetCopy(int64(offset.Uint64()), int64(size.Uint64()))
-		gas          = callContext.contract.Gas
+		value        = scope.Stack.pop()
+		offset, size = scope.Stack.pop(), scope.Stack.pop()
+		input        = scope.Memory.GetCopy(int64(offset.Uint64()), int64(size.Uint64()))
+		gas          = scope.Contract.Gas
 	)
 	if interpreter.evm.chainRules.IsEIP150 {
 		gas -= gas / 64
@@ -575,14 +575,14 @@ func opCreate(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]
 	// reuse size int for stackvalue
 	stackvalue := size
 
-	callContext.contract.UseGas(gas)
+	scope.Contract.UseGas(gas)
 	//TODO: use uint256.Int instead of converting with toBig()
 	var bigVal = big0
 	if !value.IsZero() {
 		bigVal = value.ToBig()
 	}
 
-	res, addr, returnGas, suberr := interpreter.evm.Create(callContext.contract, input, gas, bigVal)
+	res, addr, returnGas, suberr := interpreter.evm.Create(scope.Contract, input, gas, bigVal)
 	// Push item on the stack based on the returned error. If the ruleset is
 	// homestead we must check for CodeStoreOutOfGasError (homestead only
 	// rule) and treat as an error, if the ruleset is frontier we must
@@ -594,8 +594,8 @@ func opCreate(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]
 	} else {
 		stackvalue.SetBytes(addr.Bytes())
 	}
-	callContext.stack.push(&stackvalue)
-	callContext.contract.Gas += returnGas
+	scope.Stack.push(&stackvalue)
+	scope.Contract.Gas += returnGas
 
 	if suberr == ErrExecutionReverted {
 		return res, nil
@@ -603,18 +603,18 @@ func opCreate(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]
 	return nil, nil
 }
 
-func opCreate2(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+func opCreate2(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
 	var (
-		endowment    = callContext.stack.pop()
-		offset, size = callContext.stack.pop(), callContext.stack.pop()
-		salt         = callContext.stack.pop()
-		input        = callContext.memory.GetCopy(int64(offset.Uint64()), int64(size.Uint64()))
-		gas          = callContext.contract.Gas
+		endowment    = scope.Stack.pop()
+		offset, size = scope.Stack.pop(), scope.Stack.pop()
+		salt         = scope.Stack.pop()
+		input        = scope.Memory.GetCopy(int64(offset.Uint64()), int64(size.Uint64()))
+		gas          = scope.Contract.Gas
 	)
 
 	// Apply EIP150
 	gas -= gas / 64
-	callContext.contract.UseGas(gas)
+	scope.Contract.UseGas(gas)
 	// reuse size int for stackvalue
 	stackvalue := size
 	//TODO: use uint256.Int instead of converting with toBig()
@@ -622,7 +622,7 @@ func opCreate2(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([
 	if !endowment.IsZero() {
 		bigEndowment = endowment.ToBig()
 	}
-	res, addr, returnGas, suberr := interpreter.evm.Create2(callContext.contract, input, gas,
+	res, addr, returnGas, suberr := interpreter.evm.Create2(scope.Contract, input, gas,
 		bigEndowment, &salt)
 	// Push item on the stack based on the returned error.
 	if suberr != nil {
@@ -630,8 +630,8 @@ func opCreate2(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([
 	} else {
 		stackvalue.SetBytes(addr.Bytes())
 	}
-	callContext.stack.push(&stackvalue)
-	callContext.contract.Gas += returnGas
+	scope.Stack.push(&stackvalue)
+	scope.Contract.Gas += returnGas
 
 	if suberr == ErrExecutionReverted {
 		return res, nil
@@ -639,8 +639,8 @@ func opCreate2(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([
 	return nil, nil
 }
 
-func opCall(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	stack := callContext.stack
+func opCall(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	stack := scope.Stack
 	// Pop gas. The actual gas in interpreter.evm.callGasTemp.
 	// We can use this as a temporary value
 	temp := stack.pop()
@@ -649,7 +649,7 @@ func opCall(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]by
 	addr, value, inOffset, inSize, retOffset, retSize := stack.pop(), stack.pop(), stack.pop(), stack.pop(), stack.pop(), stack.pop()
 	toAddr := common.Address(addr.Bytes20())
 	// Get the arguments from the memory.
-	args := callContext.memory.GetPtr(int64(inOffset.Uint64()), int64(inSize.Uint64()))
+	args := scope.Memory.GetPtr(int64(inOffset.Uint64()), int64(inSize.Uint64()))
 
 	var bigVal = big0
 	//TODO: use uint256.Int instead of converting with toBig()
@@ -660,7 +660,7 @@ func opCall(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]by
 		bigVal = value.ToBig()
 	}
 
-	ret, returnGas, err := interpreter.evm.Call(callContext.contract, toAddr, args, gas, bigVal)
+	ret, returnGas, err := interpreter.evm.Call(scope.Contract, toAddr, args, gas, bigVal)
 
 	if err != nil {
 		temp.Clear()
@@ -669,16 +669,16 @@ func opCall(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]by
 	}
 	stack.push(&temp)
 	if err == nil || err == ErrExecutionReverted {
-		callContext.memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
+		scope.Memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
 	}
-	callContext.contract.Gas += returnGas
+	scope.Contract.Gas += returnGas
 
 	return ret, nil
 }
 
-func opCallCode(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+func opCallCode(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
 	// Pop gas. The actual gas is in interpreter.evm.callGasTemp.
-	stack := callContext.stack
+	stack := scope.Stack
 	// We use it as a temporary value
 	temp := stack.pop()
 	gas := interpreter.evm.callGasTemp
@@ -686,7 +686,7 @@ func opCallCode(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) (
 	addr, value, inOffset, inSize, retOffset, retSize := stack.pop(), stack.pop(), stack.pop(), stack.pop(), stack.pop(), stack.pop()
 	toAddr := common.Address(addr.Bytes20())
 	// Get arguments from the memory.
-	args := callContext.memory.GetPtr(int64(inOffset.Uint64()), int64(inSize.Uint64()))
+	args := scope.Memory.GetPtr(int64(inOffset.Uint64()), int64(inSize.Uint64()))
 
 	//TODO: use uint256.Int instead of converting with toBig()
 	var bigVal = big0
@@ -695,7 +695,7 @@ func opCallCode(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) (
 		bigVal = value.ToBig()
 	}
 
-	ret, returnGas, err := interpreter.evm.CallCode(callContext.contract, toAddr, args, gas, bigVal)
+	ret, returnGas, err := interpreter.evm.CallCode(scope.Contract, toAddr, args, gas, bigVal)
 	if err != nil {
 		temp.Clear()
 	} else {
@@ -703,15 +703,15 @@ func opCallCode(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) (
 	}
 	stack.push(&temp)
 	if err == nil || err == ErrExecutionReverted {
-		callContext.memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
+		scope.Memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
 	}
-	callContext.contract.Gas += returnGas
+	scope.Contract.Gas += returnGas
 
 	return ret, nil
 }
 
-func opDelegateCall(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	stack := callContext.stack
+func opDelegateCall(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	stack := scope.Stack
 	// Pop gas. The actual gas is in interpreter.evm.callGasTemp.
 	// We use it as a temporary value
 	temp := stack.pop()
@@ -720,9 +720,9 @@ func opDelegateCall(pc *uint64, interpreter *EVMInterpreter, callContext *callCt
 	addr, inOffset, inSize, retOffset, retSize := stack.pop(), stack.pop(), stack.pop(), stack.pop(), stack.pop()
 	toAddr := common.Address(addr.Bytes20())
 	// Get arguments from the memory.
-	args := callContext.memory.GetPtr(int64(inOffset.Uint64()), int64(inSize.Uint64()))
+	args := scope.Memory.GetPtr(int64(inOffset.Uint64()), int64(inSize.Uint64()))
 
-	ret, returnGas, err := interpreter.evm.DelegateCall(callContext.contract, toAddr, args, gas)
+	ret, returnGas, err := interpreter.evm.DelegateCall(scope.Contract, toAddr, args, gas)
 	if err != nil {
 		temp.Clear()
 	} else {
@@ -730,16 +730,16 @@ func opDelegateCall(pc *uint64, interpreter *EVMInterpreter, callContext *callCt
 	}
 	stack.push(&temp)
 	if err == nil || err == ErrExecutionReverted {
-		callContext.memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
+		scope.Memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
 	}
-	callContext.contract.Gas += returnGas
+	scope.Contract.Gas += returnGas
 
 	return ret, nil
 }
 
-func opStaticCall(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+func opStaticCall(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
 	// Pop gas. The actual gas is in interpreter.evm.callGasTemp.
-	stack := callContext.stack
+	stack := scope.Stack
 	// We use it as a temporary value
 	temp := stack.pop()
 	gas := interpreter.evm.callGasTemp
@@ -747,9 +747,9 @@ func opStaticCall(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx)
 	addr, inOffset, inSize, retOffset, retSize := stack.pop(), stack.pop(), stack.pop(), stack.pop(), stack.pop()
 	toAddr := common.Address(addr.Bytes20())
 	// Get arguments from the memory.
-	args := callContext.memory.GetPtr(int64(inOffset.Uint64()), int64(inSize.Uint64()))
+	args := scope.Memory.GetPtr(int64(inOffset.Uint64()), int64(inSize.Uint64()))
 
-	ret, returnGas, err := interpreter.evm.StaticCall(callContext.contract, toAddr, args, gas)
+	ret, returnGas, err := interpreter.evm.StaticCall(scope.Contract, toAddr, args, gas)
 	if err != nil {
 		temp.Clear()
 	} else {
@@ -757,36 +757,36 @@ func opStaticCall(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx)
 	}
 	stack.push(&temp)
 	if err == nil || err == ErrExecutionReverted {
-		callContext.memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
+		scope.Memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
 	}
-	callContext.contract.Gas += returnGas
+	scope.Contract.Gas += returnGas
 
 	return ret, nil
 }
 
-func opReturn(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	offset, size := callContext.stack.pop(), callContext.stack.pop()
-	ret := callContext.memory.GetPtr(int64(offset.Uint64()), int64(size.Uint64()))
+func opReturn(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	offset, size := scope.Stack.pop(), scope.Stack.pop()
+	ret := scope.Memory.GetPtr(int64(offset.Uint64()), int64(size.Uint64()))
 
 	return ret, nil
 }
 
-func opRevert(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	offset, size := callContext.stack.pop(), callContext.stack.pop()
-	ret := callContext.memory.GetPtr(int64(offset.Uint64()), int64(size.Uint64()))
+func opRevert(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	offset, size := scope.Stack.pop(), scope.Stack.pop()
+	ret := scope.Memory.GetPtr(int64(offset.Uint64()), int64(size.Uint64()))
 
 	return ret, nil
 }
 
-func opStop(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+func opStop(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
 	return nil, nil
 }
 
-func opSuicide(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-	beneficiary := callContext.stack.pop()
-	balance := interpreter.evm.StateDB.GetBalance(callContext.contract.Address())
+func opSuicide(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	beneficiary := scope.Stack.pop()
+	balance := interpreter.evm.StateDB.GetBalance(scope.Contract.Address())
 	interpreter.evm.StateDB.AddBalance(beneficiary.Bytes20(), balance)
-	interpreter.evm.StateDB.Suicide(callContext.contract.Address())
+	interpreter.evm.StateDB.Suicide(scope.Contract.Address())
 	return nil, nil
 }
 
@@ -794,18 +794,18 @@ func opSuicide(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([
 
 // make log instruction function
 func makeLog(size int) executionFunc {
-	return func(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	return func(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
 		topics := make([]common.Hash, size)
-		stack := callContext.stack
+		stack := scope.Stack
 		mStart, mSize := stack.pop(), stack.pop()
 		for i := 0; i < size; i++ {
 			addr := stack.pop()
 			topics[i] = addr.Bytes32()
 		}
 
-		d := callContext.memory.GetCopy(int64(mStart.Uint64()), int64(mSize.Uint64()))
+		d := scope.Memory.GetCopy(int64(mStart.Uint64()), int64(mSize.Uint64()))
 		interpreter.evm.StateDB.AddLog(&types.Log{
-			Address: callContext.contract.Address(),
+			Address: scope.Contract.Address(),
 			Topics:  topics,
 			Data:    d,
 			// This is a non-consensus field, but assigned here because
@@ -818,24 +818,24 @@ func makeLog(size int) executionFunc {
 }
 
 // opPush1 is a specialized version of pushN
-func opPush1(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+func opPush1(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
 	var (
-		codeLen = uint64(len(callContext.contract.Code))
+		codeLen = uint64(len(scope.Contract.Code))
 		integer = new(uint256.Int)
 	)
 	*pc += 1
 	if *pc < codeLen {
-		callContext.stack.push(integer.SetUint64(uint64(callContext.contract.Code[*pc])))
+		scope.Stack.push(integer.SetUint64(uint64(scope.Contract.Code[*pc])))
 	} else {
-		callContext.stack.push(integer.Clear())
+		scope.Stack.push(integer.Clear())
 	}
 	return nil, nil
 }
 
 // make push instruction function
 func makePush(size uint64, pushByteSize int) executionFunc {
-	return func(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-		codeLen := len(callContext.contract.Code)
+	return func(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+		codeLen := len(scope.Contract.Code)
 
 		startMin := codeLen
 		if int(*pc+1) < startMin {
@@ -848,8 +848,8 @@ func makePush(size uint64, pushByteSize int) executionFunc {
 		}
 
 		integer := new(uint256.Int)
-		callContext.stack.push(integer.SetBytes(common.RightPadBytes(
-			callContext.contract.Code[startMin:endMin], pushByteSize)))
+		scope.Stack.push(integer.SetBytes(common.RightPadBytes(
+			scope.Contract.Code[startMin:endMin], pushByteSize)))
 
 		*pc += size
 		return nil, nil
@@ -858,8 +858,8 @@ func makePush(size uint64, pushByteSize int) executionFunc {
 
 // make dup instruction function
 func makeDup(size int64) executionFunc {
-	return func(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-		callContext.stack.dup(int(size))
+	return func(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+		scope.Stack.dup(int(size))
 		return nil, nil
 	}
 }
@@ -868,8 +868,8 @@ func makeDup(size int64) executionFunc {
 func makeSwap(size int64) executionFunc {
 	// switch n + 1 otherwise n would be swapped with n
 	size++
-	return func(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
-		callContext.stack.swap(int(size))
+	return func(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+		scope.Stack.swap(int(size))
 		return nil, nil
 	}
 }

core/vm/instructions_test.go

@@ -104,7 +104,7 @@ func testTwoOperandOp(t *testing.T, tests []TwoOperandTestcase, opFn executionFu
 		expected := new(uint256.Int).SetBytes(common.Hex2Bytes(test.Expected))
 		stack.push(x)
 		stack.push(y)
-		opFn(&pc, evmInterpreter, &callCtx{nil, stack, nil})
+		opFn(&pc, evmInterpreter, &ScopeContext{nil, stack, nil})
 		if len(stack.data) != 1 {
 			t.Errorf("Expected one item on stack after %v, got %d: ", name, len(stack.data))
 		}
@@ -219,7 +219,7 @@ func TestAddMod(t *testing.T) {
 		stack.push(z)
 		stack.push(y)
 		stack.push(x)
-		opAddmod(&pc, evmInterpreter, &callCtx{nil, stack, nil})
+		opAddmod(&pc, evmInterpreter, &ScopeContext{nil, stack, nil})
 		actual := stack.pop()
 		if actual.Cmp(expected) != 0 {
 			t.Errorf("Testcase %d, expected  %x, got %x", i, expected, actual)
@@ -241,7 +241,7 @@ func getResult(args []*twoOperandParams, opFn executionFunc) []TwoOperandTestcas
 		y := new(uint256.Int).SetBytes(common.Hex2Bytes(param.y))
 		stack.push(x)
 		stack.push(y)
-		opFn(&pc, interpreter, &callCtx{nil, stack, nil})
+		opFn(&pc, interpreter, &ScopeContext{nil, stack, nil})
 		actual := stack.pop()
 		result[i] = TwoOperandTestcase{param.x, param.y, fmt.Sprintf("%064x", actual)}
 	}
@@ -299,7 +299,7 @@ func opBenchmark(bench *testing.B, op executionFunc, args ...string) {
 			a.SetBytes(arg)
 			stack.push(a)
 		}
-		op(&pc, evmInterpreter, &callCtx{nil, stack, nil})
+		op(&pc, evmInterpreter, &ScopeContext{nil, stack, nil})
 		stack.pop()
 	}
 }
@@ -525,12 +525,12 @@ func TestOpMstore(t *testing.T) {
 	pc := uint64(0)
 	v := "abcdef00000000000000abba000000000deaf000000c0de00100000000133700"
 	stack.pushN(*new(uint256.Int).SetBytes(common.Hex2Bytes(v)), *new(uint256.Int))
-	opMstore(&pc, evmInterpreter, &callCtx{mem, stack, nil})
+	opMstore(&pc, evmInterpreter, &ScopeContext{mem, stack, nil})
 	if got := common.Bytes2Hex(mem.GetCopy(0, 32)); got != v {
 		t.Fatalf("Mstore fail, got %v, expected %v", got, v)
 	}
 	stack.pushN(*new(uint256.Int).SetUint64(0x1), *new(uint256.Int))
-	opMstore(&pc, evmInterpreter, &callCtx{mem, stack, nil})
+	opMstore(&pc, evmInterpreter, &ScopeContext{mem, stack, nil})
 	if common.Bytes2Hex(mem.GetCopy(0, 32)) != "0000000000000000000000000000000000000000000000000000000000000001" {
 		t.Fatalf("Mstore failed to overwrite previous value")
 	}
@@ -553,7 +553,7 @@ func BenchmarkOpMstore(bench *testing.B) {
 	bench.ResetTimer()
 	for i := 0; i < bench.N; i++ {
 		stack.pushN(*value, *memStart)
-		opMstore(&pc, evmInterpreter, &callCtx{mem, stack, nil})
+		opMstore(&pc, evmInterpreter, &ScopeContext{mem, stack, nil})
 	}
 }
 
@@ -572,7 +572,7 @@ func BenchmarkOpSHA3(bench *testing.B) {
 	bench.ResetTimer()
 	for i := 0; i < bench.N; i++ {
 		stack.pushN(*uint256.NewInt().SetUint64(32), *start)
-		opSha3(&pc, evmInterpreter, &callCtx{mem, stack, nil})
+		opSha3(&pc, evmInterpreter, &ScopeContext{mem, stack, nil})
 	}
 }
 

core/vm/interpreter.go

@@ -62,12 +62,12 @@ type Interpreter interface {
 	CanRun([]byte) bool
 }
 
-// callCtx contains the things that are per-call, such as stack and memory,
+// ScopeContext contains the things that are per-call, such as stack and memory,
 // but not transients like pc and gas
-type callCtx struct {
-	memory   *Memory
-	stack    *Stack
-	contract *Contract
+type ScopeContext struct {
+	Memory   *Memory
+	Stack    *Stack
+	Contract *Contract
 }
 
 // keccakState wraps sha3.state. In addition to the usual hash methods, it also supports
@@ -163,10 +163,10 @@ func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (
 		op          OpCode        // current opcode
 		mem         = NewMemory() // bound memory
 		stack       = newstack()  // local stack
-		callContext = &callCtx{
-			memory:   mem,
-			stack:    stack,
-			contract: contract,
+		callContext = &ScopeContext{
+			Memory:   mem,
+			Stack:    stack,
+			Contract: contract,
 		}
 		// For optimisation reason we're using uint64 as the program counter.
 		// It's theoretically possible to go above 2^64. The YP defines the PC
@@ -191,9 +191,9 @@ func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (
 		defer func() {
 			if err != nil {
 				if !logged {
-					in.cfg.Tracer.CaptureState(in.evm, pcCopy, op, gasCopy, cost, mem, stack, in.returnData, contract, in.evm.depth, err)
+					in.cfg.Tracer.CaptureState(in.evm, pcCopy, op, gasCopy, cost, callContext, in.returnData, in.evm.depth, err)
 				} else {
-					in.cfg.Tracer.CaptureFault(in.evm, pcCopy, op, gasCopy, cost, mem, stack, contract, in.evm.depth, err)
+					in.cfg.Tracer.CaptureFault(in.evm, pcCopy, op, gasCopy, cost, callContext, in.evm.depth, err)
 				}
 			}
 		}()
@@ -275,7 +275,7 @@ func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (
 		}
 
 		if in.cfg.Debug {
-			in.cfg.Tracer.CaptureState(in.evm, pc, op, gasCopy, cost, mem, stack, in.returnData, contract, in.evm.depth, err)
+			in.cfg.Tracer.CaptureState(in.evm, pc, op, gasCopy, cost, callContext, in.returnData, in.evm.depth, err)
 			logged = true
 		}
 

core/vm/jump_table.go

@@ -21,7 +21,7 @@ import (
 )
 
 type (
-	executionFunc func(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error)
+	executionFunc func(pc *uint64, interpreter *EVMInterpreter, callContext *ScopeContext) ([]byte, error)
 	gasFunc       func(*EVM, *Contract, *Stack, *Memory, uint64) (uint64, error) // last parameter is the requested memory size as a uint64
 	// memorySizeFunc returns the required size, and whether the operation overflowed a uint64
 	memorySizeFunc func(*Stack) (size uint64, overflow bool)

core/vm/logger.go

@@ -18,7 +18,6 @@ package vm
 
 import (
 	"encoding/hex"
-	"errors"
 	"fmt"
 	"io"
 	"math/big"
@@ -32,8 +31,6 @@ import (
 	"github.com/ethereum/go-ethereum/params"
 )
 
-var errTraceLimitReached = errors.New("the number of logs reached the specified limit")
-
 // Storage represents a contract's storage.
 type Storage map[common.Hash]common.Hash
 
@@ -107,10 +104,10 @@ func (s *StructLog) ErrorString() string {
 // Note that reference types are actual VM data structures; make copies
 // if you need to retain them beyond the current call.
 type Tracer interface {
-	CaptureStart(from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) error
-	CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, rData []byte, contract *Contract, depth int, err error) error
-	CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, contract *Contract, depth int, err error) error
-	CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error) error
+	CaptureStart(env *EVM, from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int)
+	CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, rData []byte, depth int, err error)
+	CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, depth int, err error)
+	CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error)
 }
 
 // StructLogger is an EVM state logger and implements Tracer.
@@ -139,17 +136,19 @@ func NewStructLogger(cfg *LogConfig) *StructLogger {
 }
 
 // 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
+func (l *StructLogger) CaptureStart(env *EVM, from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) {
 }
 
 // CaptureState logs a new structured log message and pushes it out to the environment
 //
 // CaptureState also tracks SLOAD/SSTORE ops to track storage change.
-func (l *StructLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, rData []byte, contract *Contract, depth int, err error) error {
+func (l *StructLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, rData []byte, depth int, err error) {
+	memory := scope.Memory
+	stack := scope.Stack
+	contract := scope.Contract
 	// check if already accumulated the specified number of logs
 	if l.cfg.Limit != 0 && l.cfg.Limit <= len(l.logs) {
-		return errTraceLimitReached
+		return
 	}
 	// Copy a snapshot of the current memory state to a new buffer
 	var mem []byte
@@ -199,17 +198,15 @@ func (l *StructLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost ui
 	// create a new snapshot of the EVM.
 	log := StructLog{pc, op, gas, cost, mem, memory.Len(), stck, rdata, storage, depth, env.StateDB.GetRefund(), err}
 	l.logs = append(l.logs, log)
-	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
+func (l *StructLogger) CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, depth int, err error) {
 }
 
 // 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 {
+func (l *StructLogger) CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error) {
 	l.output = output
 	l.err = err
 	if l.cfg.Debug {
@@ -218,7 +215,6 @@ func (l *StructLogger) CaptureEnd(output []byte, gasUsed uint64, t time.Duration
 			fmt.Printf(" error: %v\n", err)
 		}
 	}
-	return nil
 }
 
 // StructLogs returns the captured log entries.
@@ -292,7 +288,7 @@ func NewMarkdownLogger(cfg *LogConfig, writer io.Writer) *mdLogger {
 	return l
 }
 
-func (t *mdLogger) CaptureStart(from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) error {
+func (t *mdLogger) CaptureStart(env *EVM, from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) {
 	if !create {
 		fmt.Fprintf(t.out, "From: `%v`\nTo: `%v`\nData: `0x%x`\nGas: `%d`\nValue `%v` wei\n",
 			from.String(), to.String(),
@@ -307,10 +303,11 @@ func (t *mdLogger) CaptureStart(from common.Address, to common.Address, create b
 |  Pc   |      Op     | Cost |   Stack   |   RStack  |  Refund |
 |-------|-------------|------|-----------|-----------|---------|
 `)
-	return nil
 }
 
-func (t *mdLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, rData []byte, contract *Contract, depth int, err error) error {
+// CaptureState also tracks SLOAD/SSTORE ops to track storage change.
+func (t *mdLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, rData []byte, depth int, err error) {
+	stack := scope.Stack
 	fmt.Fprintf(t.out, "| %4d  | %10v  |  %3d |", pc, op, cost)
 
 	if !t.cfg.DisableStack {
@@ -327,18 +324,13 @@ func (t *mdLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64
 	if err != nil {
 		fmt.Fprintf(t.out, "Error: %v\n", err)
 	}
-	return nil
 }
 
-func (t *mdLogger) CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, contract *Contract, depth int, err error) error {
-
+func (t *mdLogger) CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, depth int, err error) {
 	fmt.Fprintf(t.out, "\nError: at pc=%d, op=%v: %v\n", pc, op, err)
-
-	return nil
 }
 
-func (t *mdLogger) CaptureEnd(output []byte, gasUsed uint64, tm time.Duration, err error) error {
+func (t *mdLogger) CaptureEnd(output []byte, gasUsed uint64, tm time.Duration, err error) {
 	fmt.Fprintf(t.out, "\nOutput: `0x%x`\nConsumed gas: `%d`\nError: `%v`\n",
 		output, gasUsed, err)
-	return nil
 }

core/vm/logger_json.go

@@ -41,12 +41,16 @@ func NewJSONLogger(cfg *LogConfig, writer io.Writer) *JSONLogger {
 	return l
 }
 
-func (l *JSONLogger) CaptureStart(from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) error {
-	return nil
+func (l *JSONLogger) CaptureStart(env *EVM, from, to common.Address, create bool, input []byte, gas uint64, value *big.Int) {
 }
 
+func (l *JSONLogger) CaptureFault(*EVM, uint64, OpCode, uint64, uint64, *ScopeContext, int, error) {}
+
 // CaptureState outputs state information on the logger.
-func (l *JSONLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, rData []byte, contract *Contract, depth int, err error) error {
+func (l *JSONLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, rData []byte, depth int, err error) {
+	memory := scope.Memory
+	stack := scope.Stack
+
 	log := StructLog{
 		Pc:            pc,
 		Op:            op,
@@ -72,16 +76,11 @@ func (l *JSONLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint
 	if !l.cfg.DisableReturnData {
 		log.ReturnData = rData
 	}
-	return l.encoder.Encode(log)
-}
-
-// CaptureFault outputs state information on the logger.
-func (l *JSONLogger) CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, contract *Contract, depth int, err error) error {
-	return nil
+	l.encoder.Encode(log)
 }
 
 // CaptureEnd is triggered at end of execution.
-func (l *JSONLogger) CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error) error {
+func (l *JSONLogger) CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error) {
 	type endLog struct {
 		Output  string              `json:"output"`
 		GasUsed math.HexOrDecimal64 `json:"gasUsed"`
@@ -89,7 +88,7 @@ func (l *JSONLogger) CaptureEnd(output []byte, gasUsed uint64, t time.Duration,
 		Err     string              `json:"error,omitempty"`
 	}
 	if err != nil {
-		return l.encoder.Encode(endLog{common.Bytes2Hex(output), math.HexOrDecimal64(gasUsed), t, err.Error()})
+		l.encoder.Encode(endLog{common.Bytes2Hex(output), math.HexOrDecimal64(gasUsed), t, err.Error()})
 	}
-	return l.encoder.Encode(endLog{common.Bytes2Hex(output), math.HexOrDecimal64(gasUsed), t, ""})
+	l.encoder.Encode(endLog{common.Bytes2Hex(output), math.HexOrDecimal64(gasUsed), t, ""})
 }

core/vm/logger_test.go

@@ -53,16 +53,20 @@ func TestStoreCapture(t *testing.T) {
 	var (
 		env      = NewEVM(BlockContext{}, TxContext{}, &dummyStatedb{}, params.TestChainConfig, Config{})
 		logger   = NewStructLogger(nil)
-		mem      = NewMemory()
-		stack    = newstack()
 		contract = NewContract(&dummyContractRef{}, &dummyContractRef{}, new(big.Int), 0)
+		scope    = &ScopeContext{
+			Memory:   NewMemory(),
+			Stack:    newstack(),
+			Contract: contract,
+		}
 	)
-	stack.push(uint256.NewInt().SetUint64(1))
-	stack.push(uint256.NewInt())
+	scope.Stack.push(uint256.NewInt().SetUint64(1))
+	scope.Stack.push(uint256.NewInt())
 	var index common.Hash
-	logger.CaptureState(env, 0, SSTORE, 0, 0, mem, stack, nil, contract, 0, nil)
+	logger.CaptureState(env, 0, SSTORE, 0, 0, scope, nil, 0, nil)
 	if len(logger.storage[contract.Address()]) == 0 {
-		t.Fatalf("expected exactly 1 changed value on address %x, got %d", contract.Address(), len(logger.storage[contract.Address()]))
+		t.Fatalf("expected exactly 1 changed value on address %x, got %d", contract.Address(),
+			len(logger.storage[contract.Address()]))
 	}
 	exp := common.BigToHash(big.NewInt(1))
 	if logger.storage[contract.Address()][index] != exp {

core/vm/runtime/runtime_test.go

@@ -326,23 +326,18 @@ type stepCounter struct {
 	steps int
 }
 
-func (s *stepCounter) CaptureStart(from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) error {
-	return nil
+func (s *stepCounter) CaptureStart(env *vm.EVM, from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) {
 }
 
-func (s *stepCounter) CaptureState(env *vm.EVM, pc uint64, op vm.OpCode, gas, cost uint64, memory *vm.Memory, stack *vm.Stack, rData []byte, contract *vm.Contract, depth int, err error) error {
-	s.steps++
-	// Enable this for more output
-	//s.inner.CaptureState(env, pc, op, gas, cost, memory, stack, rStack, contract, depth, err)
-	return nil
+func (s *stepCounter) CaptureFault(env *vm.EVM, pc uint64, op vm.OpCode, gas, cost uint64, scope *vm.ScopeContext, depth int, err error) {
 }
 
-func (s *stepCounter) CaptureFault(env *vm.EVM, pc uint64, op vm.OpCode, gas, cost uint64, memory *vm.Memory, stack *vm.Stack, contract *vm.Contract, depth int, err error) error {
-	return nil
-}
+func (s *stepCounter) CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error) {}
 
-func (s *stepCounter) CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error) error {
-	return nil
+func (s *stepCounter) CaptureState(env *vm.EVM, pc uint64, op vm.OpCode, gas, cost uint64, scope *vm.ScopeContext, rData []byte, depth int, err error) {
+	s.steps++
+	// Enable this for more output
+	//s.inner.CaptureState(env, pc, op, gas, cost, memory, stack, rStack, contract, depth, err)
 }
 
 // benchmarkNonModifyingCode benchmarks code, but if the code modifies the

eth/tracers/tracer.go

@@ -287,8 +287,6 @@ func (cw *contractWrapper) pushObject(vm *duktape.Context) {
 // Tracer provides an implementation of Tracer that evaluates a Javascript
 // function for each VM execution step.
 type Tracer struct {
-	inited bool // Flag whether the context was already inited from the EVM
-
 	vm *duktape.Context // Javascript VM instance
 
 	tracerObject int // Stack index of the tracer JavaScript object
@@ -529,7 +527,7 @@ func wrapError(context string, err error) error {
 }
 
 // CaptureStart implements the Tracer interface to initialize the tracing operation.
-func (jst *Tracer) CaptureStart(from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) error {
+func (jst *Tracer) CaptureStart(env *vm.EVM, from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) {
 	jst.ctx["type"] = "CALL"
 	if create {
 		jst.ctx["type"] = "CREATE"
@@ -540,77 +538,67 @@ func (jst *Tracer) CaptureStart(from common.Address, to common.Address, create b
 	jst.ctx["gas"] = gas
 	jst.ctx["value"] = value
 
-	return nil
+	// Initialize the context
+	jst.ctx["block"] = env.Context.BlockNumber.Uint64()
+	jst.dbWrapper.db = env.StateDB
+	// Compute intrinsic gas
+	isHomestead := env.ChainConfig().IsHomestead(env.Context.BlockNumber)
+	isIstanbul := env.ChainConfig().IsIstanbul(env.Context.BlockNumber)
+	intrinsicGas, err := core.IntrinsicGas(input, nil, jst.ctx["type"] == "CREATE", isHomestead, isIstanbul)
+	if err != nil {
+		return
+	}
+	jst.ctx["intrinsicGas"] = intrinsicGas
 }
 
 // CaptureState implements the Tracer interface to trace a single step of VM execution.
-func (jst *Tracer) CaptureState(env *vm.EVM, pc uint64, op vm.OpCode, gas, cost uint64, memory *vm.Memory, stack *vm.Stack, rdata []byte, contract *vm.Contract, depth int, err error) error {
-	if jst.err == nil {
-		// Initialize the context if it wasn't done yet
-		if !jst.inited {
-			jst.ctx["block"] = env.Context.BlockNumber.Uint64()
-			// Compute intrinsic gas
-			isHomestead := env.ChainConfig().IsHomestead(env.Context.BlockNumber)
-			isIstanbul := env.ChainConfig().IsIstanbul(env.Context.BlockNumber)
-			var input []byte
-			if data, ok := jst.ctx["input"].([]byte); ok {
-				input = data
-			}
-			intrinsicGas, err := core.IntrinsicGas(input, nil, jst.ctx["type"] == "CREATE", isHomestead, isIstanbul)
-			if err != nil {
-				return err
-			}
-			jst.ctx["intrinsicGas"] = intrinsicGas
-			jst.inited = true
-		}
-		// If tracing was interrupted, set the error and stop
-		if atomic.LoadUint32(&jst.interrupt) > 0 {
-			jst.err = jst.reason
-			return nil
-		}
-		jst.opWrapper.op = op
-		jst.stackWrapper.stack = stack
-		jst.memoryWrapper.memory = memory
-		jst.contractWrapper.contract = contract
-		jst.dbWrapper.db = env.StateDB
-
-		*jst.pcValue = uint(pc)
-		*jst.gasValue = uint(gas)
-		*jst.costValue = uint(cost)
-		*jst.depthValue = uint(depth)
-		*jst.refundValue = uint(env.StateDB.GetRefund())
-
-		jst.errorValue = nil
-		if err != nil {
-			jst.errorValue = new(string)
-			*jst.errorValue = err.Error()
-		}
-		_, err := jst.call("step", "log", "db")
-		if err != nil {
-			jst.err = wrapError("step", err)
-		}
+func (jst *Tracer) CaptureState(env *vm.EVM, pc uint64, op vm.OpCode, gas, cost uint64, scope *vm.ScopeContext, rData []byte, depth int, err error) {
+	if jst.err != nil {
+		return
+	}
+	// If tracing was interrupted, set the error and stop
+	if atomic.LoadUint32(&jst.interrupt) > 0 {
+		jst.err = jst.reason
+		return
+	}
+	jst.opWrapper.op = op
+	jst.stackWrapper.stack = scope.Stack
+	jst.memoryWrapper.memory = scope.Memory
+	jst.contractWrapper.contract = scope.Contract
+
+	*jst.pcValue = uint(pc)
+	*jst.gasValue = uint(gas)
+	*jst.costValue = uint(cost)
+	*jst.depthValue = uint(depth)
+	*jst.refundValue = uint(env.StateDB.GetRefund())
+
+	jst.errorValue = nil
+	if err != nil {
+		jst.errorValue = new(string)
+		*jst.errorValue = err.Error()
+	}
+
+	if _, err := jst.call("step", "log", "db"); err != nil {
+		jst.err = wrapError("step", err)
 	}
-	return nil
 }
 
 // CaptureFault implements the Tracer interface to trace an execution fault
-// while running an opcode.
-func (jst *Tracer) CaptureFault(env *vm.EVM, pc uint64, op vm.OpCode, gas, cost uint64, memory *vm.Memory, stack *vm.Stack, contract *vm.Contract, depth int, err error) error {
-	if jst.err == nil {
-		// Apart from the error, everything matches the previous invocation
-		jst.errorValue = new(string)
-		*jst.errorValue = err.Error()
+func (jst *Tracer) CaptureFault(env *vm.EVM, pc uint64, op vm.OpCode, gas, cost uint64, scope *vm.ScopeContext, depth int, err error) {
+	if jst.err != nil {
+		return
+	}
+	// Apart from the error, everything matches the previous invocation
+	jst.errorValue = new(string)
+	*jst.errorValue = err.Error()
 
-		_, err := jst.call("fault", "log", "db")
-		if err != nil {
-			jst.err = wrapError("fault", err)
-		}
+	if _, err := jst.call("fault", "log", "db"); err != nil {
+		jst.err = wrapError("fault", err)
 	}
-	return nil
 }
 
 // CaptureEnd is called after the call finishes to finalize the tracing.
-func (jst *Tracer) CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error) error {
+func (jst *Tracer) CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error) {
 	jst.ctx["output"] = output
 	jst.ctx["time"] = t.String()
 	jst.ctx["gasUsed"] = gasUsed
@@ -618,7 +606,6 @@ func (jst *Tracer) CaptureEnd(output []byte, gasUsed uint64, t time.Duration, er
 	if err != nil {
 		jst.ctx["error"] = err.Error()
 	}
-	return nil
 }
 
 // GetResult calls the Javascript 'result' function and returns its value, or any accumulated error

eth/tracers/tracer_test.go

@@ -47,7 +47,8 @@ type dummyStatedb struct {
 	state.StateDB
 }
 
-func (*dummyStatedb) GetRefund() uint64 { return 1337 }
+func (*dummyStatedb) GetRefund() uint64                       { return 1337 }
+func (*dummyStatedb) GetBalance(addr common.Address) *big.Int { return new(big.Int) }
 
 type vmContext struct {
 	blockCtx vm.BlockContext
@@ -67,7 +68,7 @@ func runTrace(tracer *Tracer, vmctx *vmContext) (json.RawMessage, error) {
 	contract := vm.NewContract(account{}, account{}, value, startGas)
 	contract.Code = []byte{byte(vm.PUSH1), 0x1, byte(vm.PUSH1), 0x1, 0x0}
 
-	tracer.CaptureStart(contract.Caller(), contract.Address(), false, []byte{}, startGas, value)
+	tracer.CaptureStart(env, contract.Caller(), contract.Address(), false, []byte{}, startGas, value)
 	ret, err := env.Interpreter().Run(contract, []byte{}, false)
 	tracer.CaptureEnd(ret, startGas-contract.Gas, 1, err)
 	if err != nil {
@@ -150,14 +151,55 @@ func TestHaltBetweenSteps(t *testing.T) {
 		t.Fatal(err)
 	}
 	env := vm.NewEVM(vm.BlockContext{BlockNumber: big.NewInt(1)}, vm.TxContext{}, &dummyStatedb{}, params.TestChainConfig, vm.Config{Debug: true, Tracer: tracer})
-	contract := vm.NewContract(&account{}, &account{}, big.NewInt(0), 0)
+	scope := &vm.ScopeContext{
+		Contract: vm.NewContract(&account{}, &account{}, big.NewInt(0), 0),
+	}
 
-	tracer.CaptureState(env, 0, 0, 0, 0, nil, nil, nil, contract, 0, nil)
+	tracer.CaptureState(env, 0, 0, 0, 0, scope, nil, 0, nil)
 	timeout := errors.New("stahp")
 	tracer.Stop(timeout)
-	tracer.CaptureState(env, 0, 0, 0, 0, nil, nil, nil, contract, 0, nil)
+	tracer.CaptureState(env, 0, 0, 0, 0, scope, nil, 0, nil)
 
 	if _, err := tracer.GetResult(); err.Error() != timeout.Error() {
 		t.Errorf("Expected timeout error, got %v", err)
 	}
 }
+
+// TestNoStepExec tests a regular value transfer (no exec), and accessing the statedb
+// in 'result'
+func TestNoStepExec(t *testing.T) {
+	runEmptyTrace := func(tracer *Tracer, vmctx *vmContext) (json.RawMessage, error) {
+		env := vm.NewEVM(vmctx.blockCtx, vmctx.txCtx, &dummyStatedb{}, params.TestChainConfig, vm.Config{Debug: true, Tracer: tracer})
+		startGas := uint64(10000)
+		contract := vm.NewContract(account{}, account{}, big.NewInt(0), startGas)
+		tracer.CaptureStart(env, contract.Caller(), contract.Address(), false, []byte{}, startGas, big.NewInt(0))
+		tracer.CaptureEnd(nil, startGas-contract.Gas, 1, nil)
+		return tracer.GetResult()
+	}
+	execTracer := func(code string) []byte {
+		t.Helper()
+		ctx := &vmContext{blockCtx: vm.BlockContext{BlockNumber: big.NewInt(1)}, txCtx: vm.TxContext{GasPrice: big.NewInt(100000)}}
+		tracer, err := New(code, ctx.txCtx)
+		if err != nil {
+			t.Fatal(err)
+		}
+		ret, err := runEmptyTrace(tracer, ctx)
+		if err != nil {
+			t.Fatal(err)
+		}
+		return ret
+	}
+	for i, tt := range []struct {
+		code string
+		want string
+	}{
+		{ // tests that we don't panic on accessing the db methods
+			code: "{depths: [], step: function() {}, fault: function() {},  result: function(ctx, db){ return db.getBalance(ctx.to)} }",
+			want: `"0"`,
+		},
+	} {
+		if have := execTracer(tt.code); tt.want != string(have) {
+			t.Errorf("testcase %d: expected return value to be %s got %s\n\tcode: %v", i, tt.want, string(have), tt.code)
+		}
+	}
+}