Simplify error handling in interpreter loop

blockchain/vm/errors.go

@@ -45,4 +45,8 @@ var (
 	ErrMaxCodeSizeExceeded   = errors.New("evm: max code size exceeded")
 	ErrInvalidJump           = errors.New("evm: invalid jump destination")
 	ErrInvalidCode           = errors.New("invalid code: must not begin with 0xef")
+
+	// errStopToken is an internal token indicating interpreter loop termination,
+	// never returned to outside callers.
+	errStopToken = errors.New("stop token")
 )

blockchain/vm/instructions.go

@@ -653,7 +653,7 @@ func opJump(pc *uint64, evm *EVM, scope *ScopeContext) ([]byte, error) {
 	if !scope.Contract.validJumpdest(pos) {
 		return nil, ErrInvalidJump
 	}
-	*pc = pos.Uint64()
+	*pc = pos.Uint64() - 1 // pc will be increased by the interpreter loop
 
 	evm.interpreter.intPool.put(pos)
 	return nil, nil
@@ -665,9 +665,7 @@ func opJumpi(pc *uint64, evm *EVM, scope *ScopeContext) ([]byte, error) {
 		if !scope.Contract.validJumpdest(pos) {
 			return nil, ErrInvalidJump
 		}
-		*pc = pos.Uint64()
-	} else {
-		*pc++
+		*pc = pos.Uint64() - 1 // pc will be increased by the interpreter loop
 	}
 
 	evm.interpreter.intPool.put(pos, cond)
@@ -719,8 +717,10 @@ func opCreate(pc *uint64, evm *EVM, scope *ScopeContext) ([]byte, error) {
 	evm.interpreter.intPool.put(value, offset, size)
 
 	if suberr == ErrExecutionReverted {
+		evm.interpreter.returnData = res // set REVERT data to return data buffer
 		return res, nil
 	}
+	evm.interpreter.returnData = nil // clear dirty return data buffer
 	return nil, nil
 }
 
@@ -747,8 +747,10 @@ func opCreate2(pc *uint64, evm *EVM, scope *ScopeContext) ([]byte, error) {
 	evm.interpreter.intPool.put(endowment, offset, size, salt)
 
 	if suberr == ErrExecutionReverted {
+		evm.interpreter.returnData = res // set REVERT data to return data buffer
 		return res, nil
 	}
+	evm.interpreter.returnData = nil // clear dirty return data buffer
 	return nil, nil
 }
 
@@ -779,6 +781,7 @@ func opCall(pc *uint64, evm *EVM, scope *ScopeContext) ([]byte, error) {
 	scope.Contract.Gas += returnGas
 
 	evm.interpreter.intPool.put(addr, value, inOffset, inSize, retOffset, retSize)
+	evm.interpreter.returnData = ret
 	return ret, nil
 }
 
@@ -809,6 +812,7 @@ func opCallCode(pc *uint64, evm *EVM, scope *ScopeContext) ([]byte, error) {
 	scope.Contract.Gas += returnGas
 
 	evm.interpreter.intPool.put(addr, value, inOffset, inSize, retOffset, retSize)
+	evm.interpreter.returnData = ret
 	return ret, nil
 }
 
@@ -835,6 +839,7 @@ func opDelegateCall(pc *uint64, evm *EVM, scope *ScopeContext) ([]byte, error) {
 	scope.Contract.Gas += returnGas
 
 	evm.interpreter.intPool.put(addr, inOffset, inSize, retOffset, retSize)
+	evm.interpreter.returnData = ret
 	return ret, nil
 }
 
@@ -861,6 +866,7 @@ func opStaticCall(pc *uint64, evm *EVM, scope *ScopeContext) ([]byte, error) {
 	scope.Contract.Gas += returnGas
 
 	evm.interpreter.intPool.put(addr, inOffset, inSize, retOffset, retSize)
+	evm.interpreter.returnData = ret
 	return ret, nil
 }
 
@@ -869,19 +875,20 @@ func opReturn(pc *uint64, evm *EVM, scope *ScopeContext) ([]byte, error) {
 	ret := scope.Memory.GetPtr(offset.Int64(), size.Int64())
 
 	evm.interpreter.intPool.put(offset, size)
-	return ret, nil
+	return ret, errStopToken
 }
 
 func opRevert(pc *uint64, evm *EVM, scope *ScopeContext) ([]byte, error) {
 	offset, size := scope.Stack.pop(), scope.Stack.pop()
 	ret := scope.Memory.GetPtr(offset.Int64(), size.Int64())
 
 	evm.interpreter.intPool.put(offset, size)
-	return ret, nil
+	evm.interpreter.returnData = ret
+	return ret, ErrExecutionReverted
 }
 
 func opStop(pc *uint64, evm *EVM, scope *ScopeContext) ([]byte, error) {
-	return nil, nil
+	return nil, errStopToken
 }
 
 func opSelfdestruct(pc *uint64, evm *EVM, scope *ScopeContext) ([]byte, error) {
@@ -896,7 +903,7 @@ func opSelfdestruct(pc *uint64, evm *EVM, scope *ScopeContext) ([]byte, error) {
 	// 	evm.interpreter.cfg.Tracer.CaptureExit([]byte{}, 0, nil)
 	// }
 
-	return nil, nil
+	return nil, errStopToken
 }
 
 // opPush1 is a specialized version of pushN
@@ -930,7 +937,7 @@ func opSelfdestruct6780(pc *uint64, evm *EVM, scope *ScopeContext) ([]byte, erro
 	// 	tracer.CaptureExit([]byte{}, 0, nil)
 	// }
 
-	return nil, nil
+	return nil, errStopToken
 }
 
 // following functions are used by the instruction jump  table

blockchain/vm/interpreter.go

@@ -343,27 +343,20 @@ func (in *EVMInterpreter) Run(contract *Contract, input []byte) (ret []byte, err
 		if verifyPool {
 			verifyIntegerPool(in.intPool)
 		}
-		// if the operation clears the return data (e.g. it has returning data)
-		// set the last return to the result of the operation.
-		if operation.returns {
-			in.returnData = res
-		}
 
-		switch {
-		case err != nil:
-			return nil, err // TODO-Klaytn-Issue615
-		case operation.reverts:
-			return res, ErrExecutionReverted // TODO-Klaytn-Issue615
-		case operation.halts:
-			return res, nil
-		case !operation.jumps:
-			pc++
+		if err != nil {
+			break
 		}
+		pc++
 	}
 
 	abort := atomic.LoadInt32(&in.evm.abort)
 	if (abort & CancelByTotalTimeLimit) != 0 {
 		return nil, ErrTotalTimeLimitReached // TODO-Klaytn-Issue615
 	}
-	return nil, nil
+	if err == errStopToken {
+		err = nil // clear stop token error
+	}
+
+	return res, err
 }

blockchain/vm/jump_table.go

@@ -53,11 +53,7 @@ type operation struct {
 	// This value will be used to limit the execution time of a transaction on EVM.
 	computationCost uint64
 
-	halts   bool // indicates whether the operation should halt further execution
-	jumps   bool // indicates whether the program counter should not increment
 	writes  bool // determines whether this a state modifying operation
-	reverts bool // determines whether the operation reverts state (implicitly halts)
-	returns bool // determines whether the operations sets the return data content
 }
 
 var (
@@ -153,7 +149,6 @@ func newConstantinopleInstructionSet() JumpTable {
 		maxStack:        maxStack(4, 1),
 		memorySize:      memoryCreate2,
 		writes:          true,
-		returns:         true,
 		computationCost: params.Create2ComputationCost,
 	}
 	return instructionSet
@@ -171,7 +166,6 @@ func newByzantiumInstructionSet() JumpTable {
 		minStack:        minStack(6, 1),
 		maxStack:        maxStack(6, 1),
 		memorySize:      memoryStaticCall,
-		returns:         true,
 		computationCost: params.StaticCallComputationCost,
 	}
 	instructionSet[RETURNDATASIZE] = &operation{
@@ -196,8 +190,6 @@ func newByzantiumInstructionSet() JumpTable {
 		minStack:        minStack(2, 0),
 		maxStack:        maxStack(2, 0),
 		memorySize:      memoryRevert,
-		reverts:         true,
-		returns:         true,
 		computationCost: params.RevertComputationCost,
 	}
 	return instructionSet
@@ -214,7 +206,6 @@ func newHomesteadInstructionSet() JumpTable {
 		minStack:        minStack(6, 1),
 		maxStack:        maxStack(6, 1),
 		memorySize:      memoryDelegateCall,
-		returns:         true,
 		computationCost: params.DelegateCallComputationCost,
 	}
 	return instructionSet
@@ -229,7 +220,6 @@ func newFrontierInstructionSet() JumpTable {
 			constantGas:     0,
 			minStack:        minStack(0, 0),
 			maxStack:        maxStack(0, 0),
-			halts:           true,
 			computationCost: params.StopComputationCost,
 		},
 		ADD: {
@@ -588,15 +578,13 @@ func newFrontierInstructionSet() JumpTable {
 			constantGas:     GasMidStep,
 			minStack:        minStack(1, 0),
 			maxStack:        maxStack(1, 0),
-			jumps:           true,
 			computationCost: params.JumpComputationCost,
 		},
 		JUMPI: {
 			execute:         opJumpi,
 			constantGas:     GasSlowStep,
 			minStack:        minStack(2, 0),
 			maxStack:        maxStack(2, 0),
-			jumps:           true,
 			computationCost: params.JumpiComputationCost,
 		},
 		PC: {
@@ -1128,7 +1116,6 @@ func newFrontierInstructionSet() JumpTable {
 			maxStack:        maxStack(3, 1),
 			memorySize:      memoryCreate,
 			writes:          true,
-			returns:         true,
 			computationCost: params.CreateComputationCost,
 		},
 		CALL: {
@@ -1138,7 +1125,6 @@ func newFrontierInstructionSet() JumpTable {
 			minStack:        minStack(7, 1),
 			maxStack:        maxStack(7, 1),
 			memorySize:      memoryCall,
-			returns:         true,
 			computationCost: params.CallComputationCost,
 		},
 		CALLCODE: {
@@ -1148,7 +1134,6 @@ func newFrontierInstructionSet() JumpTable {
 			minStack:        minStack(7, 1),
 			maxStack:        maxStack(7, 1),
 			memorySize:      memoryCall,
-			returns:         true,
 			computationCost: params.CallCodeComputationCost,
 		},
 		RETURN: {
@@ -1157,15 +1142,13 @@ func newFrontierInstructionSet() JumpTable {
 			minStack:        minStack(2, 0),
 			maxStack:        maxStack(2, 0),
 			memorySize:      memoryReturn,
-			halts:           true,
 			computationCost: params.ReturnComputationCost,
 		},
 		SELFDESTRUCT: {
 			execute:         opSelfdestruct,
 			dynamicGas:      gasSelfdestruct,
 			minStack:        minStack(1, 0),
 			maxStack:        maxStack(1, 0),
-			halts:           true,
 			writes:          true,
 			computationCost: params.SelfDestructComputationCost,
 		},