Resumable EVM and heap-allocated callstack (#9360)

* Add new Vm trappable interface

* Exec/Resume interface

* Basic implementation of CallCreateExecutive

* Implement resume_call and resume_create for executive

* Move convertion to call/create result to separate function

* Implement consume that converts resumable to non-resumable

* Use consume for Executive::call/create

* Resumable EVM

* Implement tracing mode without needing subtracers

* Implement vmtracer so it doesn't require extra structs for subtracing

* Use the new tracing mode in executive

* Fix most of the linting errors for cargo build

* Add the concept of stack_depth

* Add back crossbeam

* Fix some test compile

* Fix prefix address test

* Fix evm crate tests

* Fix wasm crate test compile

* Fix wasm runner compile

* Fix jsontests compile

* Fix evmbin compile

* Fix an issue with create nonce and better vm tracing interface

* Fix linting

* Fix evmbin compile

* Fix unconfirmed_substate and static_flag

* Fix an issue in create address logic

* Fix top-level tracing

* Handle builtin tracing

* Fix suicide and reward tracing index stack

* Fix an issue where trap conflicts with tracing

* Fix an issue in parent step vm tracing

* Fix revert tracing

* Fix evmbin tests

* Remove params clone

* Fix TODO proofs

* Fix jsontests compile

* Fix evmbin merge issue

* Fix wasm merge issue

* Fix wasm test

* Fix ethcore merge warnings

* Fix evmbin compile

* Better expect messages and add some trace::skip_one asserts

ethcore/evm/src/evm.rs

@@ -62,7 +62,7 @@ impl Finalize for Error {
 }
 
 /// Cost calculation type. For low-gas usage we calculate costs using usize instead of U256
-pub trait CostType: Sized + From<usize> + Copy
+pub trait CostType: Sized + From<usize> + Copy + Send
 	+ ops::Mul<Output=Self> + ops::Div<Output=Self> + ops::Add<Output=Self> +ops::Sub<Output=Self>
 	+ ops::Shr<usize, Output=Self> + ops::Shl<usize, Output=Self>
 	+ cmp::Ord + fmt::Debug {

ethcore/evm/src/factory.rs

@@ -17,7 +17,7 @@
 //! Evm factory.
 //!
 use std::sync::Arc;
-use vm::{Vm, Schedule};
+use vm::{Exec, Schedule};
 use ethereum_types::U256;
 use super::vm::ActionParams;
 use super::interpreter::SharedCache;
@@ -33,7 +33,7 @@ pub struct Factory {
 impl Factory {
 	/// Create fresh instance of VM
 	/// Might choose implementation depending on supplied gas.
-	pub fn create(&self, params: ActionParams, schedule: &Schedule, depth: usize) -> Box<Vm> {
+	pub fn create(&self, params: ActionParams, schedule: &Schedule, depth: usize) -> Box<Exec> {
 		match self.evm {
 			VMType::Interpreter => if Self::can_fit_in_usize(&params.gas) {
 				Box::new(super::interpreter::Interpreter::<usize>::new(params, self.evm_cache.clone(), schedule, depth))

ethcore/evm/src/interpreter/mod.rs

@@ -32,7 +32,8 @@ use ethereum_types::{U256, U512, H256, Address};
 
 use vm::{
 	self, ActionParams, ParamsType, ActionValue, CallType, MessageCallResult,
-	ContractCreateResult, CreateContractAddress, ReturnData, GasLeft, Schedule
+	ContractCreateResult, CreateContractAddress, ReturnData, GasLeft, Schedule,
+	TrapKind, TrapError
 };
 
 use evm::CostType;
@@ -103,6 +104,7 @@ enum InstructionResult<Gas> {
 		apply: bool,
 	},
 	StopExecution,
+	Trap(TrapKind),
 }
 
 enum Never {}
@@ -161,6 +163,7 @@ pub enum InterpreterResult {
 	Done(vm::Result<GasLeft>),
 	/// The VM can continue to run.
 	Continue,
+	Trap(TrapKind),
 }
 
 impl From<vm::Error> for InterpreterResult {
@@ -182,22 +185,89 @@ pub struct Interpreter<Cost: CostType> {
 	valid_jump_destinations: Option<Arc<BitSet>>,
 	gasometer: Option<Gasometer<Cost>>,
 	stack: VecStack<U256>,
+	resume_output_range: Option<(U256, U256)>,
+	resume_result: Option<InstructionResult<Cost>>,
+	last_stack_ret_len: usize,
 	_type: PhantomData<Cost>,
 }
 
-impl<Cost: CostType> vm::Vm for Interpreter<Cost> {
-	fn exec(&mut self, ext: &mut vm::Ext) -> vm::Result<GasLeft> {
+impl<Cost: 'static + CostType> vm::Exec for Interpreter<Cost> {
+	fn exec(mut self: Box<Self>, ext: &mut vm::Ext) -> vm::ExecTrapResult<GasLeft> {
 		loop {
 			let result = self.step(ext);
 			match result {
 				InterpreterResult::Continue => {},
-				InterpreterResult::Done(value) => return value,
+				InterpreterResult::Done(value) => return Ok(value),
+				InterpreterResult::Trap(trap) => match trap {
+					TrapKind::Call(params) => {
+						return Err(TrapError::Call(params, self));
+					},
+					TrapKind::Create(params, address) => {
+						return Err(TrapError::Create(params, address, self));
+					},
+				},
 				InterpreterResult::Stopped => panic!("Attempted to execute an already stopped VM.")
 			}
 		}
 	}
 }
 
+impl<Cost: 'static + CostType> vm::ResumeCall for Interpreter<Cost> {
+	fn resume_call(mut self: Box<Self>, result: MessageCallResult) -> Box<vm::Exec> {
+		{
+			let this = &mut *self;
+			let (out_off, out_size) = this.resume_output_range.take().expect("Box<ResumeCall> is obtained from a call opcode; resume_output_range is always set after those opcodes are executed; qed");
+
+			match result {
+				MessageCallResult::Success(gas_left, data) => {
+					let output = this.mem.writeable_slice(out_off, out_size);
+					let len = cmp::min(output.len(), data.len());
+					(&mut output[..len]).copy_from_slice(&data[..len]);
+
+					this.return_data = data;
+					this.stack.push(U256::one());
+					this.resume_result = Some(InstructionResult::UnusedGas(Cost::from_u256(gas_left).expect("Gas left cannot be greater than current one")));
+				},
+				MessageCallResult::Reverted(gas_left, data) => {
+					let output = this.mem.writeable_slice(out_off, out_size);
+					let len = cmp::min(output.len(), data.len());
+					(&mut output[..len]).copy_from_slice(&data[..len]);
+
+					this.return_data = data;
+					this.stack.push(U256::zero());
+					this.resume_result = Some(InstructionResult::UnusedGas(Cost::from_u256(gas_left).expect("Gas left cannot be greater than current one")));
+				},
+				MessageCallResult::Failed => {
+					this.stack.push(U256::zero());
+					this.resume_result = Some(InstructionResult::Ok);
+				},
+			}
+		}
+		self
+	}
+}
+
+impl<Cost: 'static + CostType> vm::ResumeCreate for Interpreter<Cost> {
+	fn resume_create(mut self: Box<Self>, result: ContractCreateResult) -> Box<vm::Exec> {
+		match result {
+			ContractCreateResult::Created(address, gas_left) => {
+				self.stack.push(address_to_u256(address));
+				self.resume_result = Some(InstructionResult::UnusedGas(Cost::from_u256(gas_left).expect("Gas left cannot be greater.")));
+			},
+			ContractCreateResult::Reverted(gas_left, return_data) => {
+				self.stack.push(U256::zero());
+				self.return_data = return_data;
+				self.resume_result = Some(InstructionResult::UnusedGas(Cost::from_u256(gas_left).expect("Gas left cannot be greater.")));
+			},
+			ContractCreateResult::Failed => {
+				self.stack.push(U256::zero());
+				self.resume_result = Some(InstructionResult::Ok);
+			},
+		}
+		self
+	}
+}
+
 impl<Cost: CostType> Interpreter<Cost> {
 	/// Create a new `Interpreter` instance with shared cache.
 	pub fn new(mut params: ActionParams, cache: Arc<SharedCache>, schedule: &Schedule, depth: usize) -> Interpreter<Cost> {
@@ -215,6 +285,9 @@ impl<Cost: CostType> Interpreter<Cost> {
 			do_trace: true,
 			mem: Vec::new(),
 			return_data: ReturnData::empty(),
+			last_stack_ret_len: 0,
+			resume_output_range: None,
+			resume_result: None,
 			_type: PhantomData,
 		}
 	}
@@ -244,51 +317,58 @@ impl<Cost: CostType> Interpreter<Cost> {
 	/// Inner helper function for step.
 	#[inline(always)]
 	fn step_inner(&mut self, ext: &mut vm::Ext) -> Result<Never, InterpreterResult> {
-		let opcode = self.reader.code[self.reader.position];
-		let instruction = Instruction::from_u8(opcode);
-		self.reader.position += 1;
+		let result = match self.resume_result.take() {
+			Some(result) => result,
+			None => {
+				let opcode = self.reader.code[self.reader.position];
+				let instruction = Instruction::from_u8(opcode);
+				self.reader.position += 1;
 
-		// TODO: make compile-time removable if too much of a performance hit.
-		self.do_trace = self.do_trace && ext.trace_next_instruction(
-			self.reader.position - 1, opcode, self.gasometer.as_mut().expect(GASOMETER_PROOF).current_gas.as_u256(),
-		);
+				// TODO: make compile-time removable if too much of a performance hit.
+				self.do_trace = self.do_trace && ext.trace_next_instruction(
+					self.reader.position - 1, opcode, self.gasometer.as_mut().expect(GASOMETER_PROOF).current_gas.as_u256(),
+				);
 
-		let instruction = match instruction {
-			Some(i) => i,
-			None => return Err(InterpreterResult::Done(Err(vm::Error::BadInstruction {
-				instruction: opcode
-			}))),
+				let instruction = match instruction {
+					Some(i) => i,
+					None => return Err(InterpreterResult::Done(Err(vm::Error::BadInstruction {
+						instruction: opcode
+					}))),
+				};
+
+				let info = instruction.info();
+				self.last_stack_ret_len = info.ret;
+				self.verify_instruction(ext, instruction, info)?;
+
+				// Calculate gas cost
+				let requirements = self.gasometer.as_mut().expect(GASOMETER_PROOF).requirements(ext, instruction, info, &self.stack, self.mem.size())?;
+				if self.do_trace {
+					ext.trace_prepare_execute(self.reader.position - 1, opcode, requirements.gas_cost.as_u256(), Self::mem_written(instruction, &self.stack), Self::store_written(instruction, &self.stack));
+				}
+
+				self.gasometer.as_mut().expect(GASOMETER_PROOF).verify_gas(&requirements.gas_cost)?;
+				self.mem.expand(requirements.memory_required_size);
+				self.gasometer.as_mut().expect(GASOMETER_PROOF).current_mem_gas = requirements.memory_total_gas;
+				self.gasometer.as_mut().expect(GASOMETER_PROOF).current_gas = self.gasometer.as_mut().expect(GASOMETER_PROOF).current_gas - requirements.gas_cost;
+
+				evm_debug!({ self.informant.before_instruction(self.reader.position, instruction, info, &self.gasometer.as_mut().expect(GASOMETER_PROOF).current_gas, &self.stack) });
+
+				// Execute instruction
+				let current_gas = self.gasometer.as_mut().expect(GASOMETER_PROOF).current_gas;
+				let result = self.exec_instruction(
+					current_gas, ext, instruction, requirements.provide_gas
+				)?;
+
+				evm_debug!({ self.informant.after_instruction(instruction) });
+
+				result
+			},
 		};
 
-		let info = instruction.info();
-		self.verify_instruction(ext, instruction, info)?;
-
-		// Calculate gas cost
-		let requirements = self.gasometer.as_mut().expect(GASOMETER_PROOF).requirements(ext, instruction, info, &self.stack, self.mem.size())?;
-		if self.do_trace {
-			ext.trace_prepare_execute(self.reader.position - 1, opcode, requirements.gas_cost.as_u256());
+		if let InstructionResult::Trap(trap) = result {
+			return Err(InterpreterResult::Trap(trap));
 		}
 
-		self.gasometer.as_mut().expect(GASOMETER_PROOF).verify_gas(&requirements.gas_cost)?;
-		self.mem.expand(requirements.memory_required_size);
-		self.gasometer.as_mut().expect(GASOMETER_PROOF).current_mem_gas = requirements.memory_total_gas;
-		self.gasometer.as_mut().expect(GASOMETER_PROOF).current_gas = self.gasometer.as_mut().expect(GASOMETER_PROOF).current_gas - requirements.gas_cost;
-
-		evm_debug!({ self.informant.before_instruction(self.reader.position, instruction, info, &self.gasometer.as_mut().expect(GASOMETER_PROOF).current_gas, &self.stack) });
-
-		let (mem_written, store_written) = match self.do_trace {
-			true => (Self::mem_written(instruction, &self.stack), Self::store_written(instruction, &self.stack)),
-			false => (None, None),
-		};
-
-		// Execute instruction
-		let current_gas = self.gasometer.as_mut().expect(GASOMETER_PROOF).current_gas;
-		let result = self.exec_instruction(
-			current_gas, ext, instruction, requirements.provide_gas
-		)?;
-
-		evm_debug!({ self.informant.after_instruction(instruction) });
-
 		if let InstructionResult::UnusedGas(ref gas) = result {
 			self.gasometer.as_mut().expect(GASOMETER_PROOF).current_gas = self.gasometer.as_mut().expect(GASOMETER_PROOF).current_gas + *gas;
 		}
@@ -296,9 +376,8 @@ impl<Cost: CostType> Interpreter<Cost> {
 		if self.do_trace {
 			ext.trace_executed(
 				self.gasometer.as_mut().expect(GASOMETER_PROOF).current_gas.as_u256(),
-				self.stack.peek_top(info.ret),
-				mem_written.map(|(o, s)| (o, &(self.mem[o..o+s]))),
-				store_written,
+				self.stack.peek_top(self.last_stack_ret_len),
+				&self.mem,
 			);
 		}
 
@@ -451,21 +530,24 @@ impl<Cost: CostType> Interpreter<Cost> {
 
 				let contract_code = self.mem.read_slice(init_off, init_size);
 
-				let create_result = ext.create(&create_gas.as_u256(), &endowment, contract_code, address_scheme);
+				let create_result = ext.create(&create_gas.as_u256(), &endowment, contract_code, address_scheme, true);
 				return match create_result {
-					ContractCreateResult::Created(address, gas_left) => {
+					Ok(ContractCreateResult::Created(address, gas_left)) => {
 						self.stack.push(address_to_u256(address));
 						Ok(InstructionResult::UnusedGas(Cost::from_u256(gas_left).expect("Gas left cannot be greater.")))
 					},
-					ContractCreateResult::Reverted(gas_left, return_data) => {
+					Ok(ContractCreateResult::Reverted(gas_left, return_data)) => {
 						self.stack.push(U256::zero());
 						self.return_data = return_data;
 						Ok(InstructionResult::UnusedGas(Cost::from_u256(gas_left).expect("Gas left cannot be greater.")))
 					},
-					ContractCreateResult::Failed => {
+					Ok(ContractCreateResult::Failed) => {
 						self.stack.push(U256::zero());
 						Ok(InstructionResult::Ok)
 					},
+					Err(trap) => {
+						Ok(InstructionResult::Trap(trap))
+					},
 				};
 			},
 			instructions::CALL | instructions::CALLCODE | instructions::DELEGATECALL | instructions::STATICCALL => {
@@ -524,13 +606,14 @@ impl<Cost: CostType> Interpreter<Cost> {
 
 				let call_result = {
 					let input = self.mem.read_slice(in_off, in_size);
-					ext.call(&call_gas.as_u256(), sender_address, receive_address, value, input, &code_address, call_type)
+					ext.call(&call_gas.as_u256(), sender_address, receive_address, value, input, &code_address, call_type, true)
 				};
 
-				let output = self.mem.writeable_slice(out_off, out_size);
+				self.resume_output_range = Some((out_off, out_size));
 
 				return match call_result {
-					MessageCallResult::Success(gas_left, data) => {
+					Ok(MessageCallResult::Success(gas_left, data)) => {
+						let output = self.mem.writeable_slice(out_off, out_size);
 						let len = cmp::min(output.len(), data.len());
 						(&mut output[..len]).copy_from_slice(&data[..len]);
 
@@ -538,7 +621,8 @@ impl<Cost: CostType> Interpreter<Cost> {
 						self.return_data = data;
 						Ok(InstructionResult::UnusedGas(Cost::from_u256(gas_left).expect("Gas left cannot be greater than current one")))
 					},
-					MessageCallResult::Reverted(gas_left, data) => {
+					Ok(MessageCallResult::Reverted(gas_left, data)) => {
+						let output = self.mem.writeable_slice(out_off, out_size);
 						let len = cmp::min(output.len(), data.len());
 						(&mut output[..len]).copy_from_slice(&data[..len]);
 
@@ -546,10 +630,13 @@ impl<Cost: CostType> Interpreter<Cost> {
 						self.return_data = data;
 						Ok(InstructionResult::UnusedGas(Cost::from_u256(gas_left).expect("Gas left cannot be greater than current one")))
 					},
-					MessageCallResult::Failed  => {
+					Ok(MessageCallResult::Failed) => {
 						self.stack.push(U256::zero());
 						Ok(InstructionResult::Ok)
 					},
+					Err(trap) => {
+						Ok(InstructionResult::Trap(trap))
+					},
 				};
 			},
 			instructions::RETURN => {
@@ -1095,10 +1182,10 @@ mod tests {
 	use rustc_hex::FromHex;
 	use vmtype::VMType;
 	use factory::Factory;
-	use vm::{self, Vm, ActionParams, ActionValue};
+	use vm::{self, Exec, ActionParams, ActionValue};
 	use vm::tests::{FakeExt, test_finalize};
 
-	fn interpreter(params: ActionParams, ext: &vm::Ext) -> Box<Vm> {
+	fn interpreter(params: ActionParams, ext: &vm::Ext) -> Box<Exec> {
 		Factory::new(VMType::Interpreter, 1).create(params, ext.schedule(), ext.depth())
 	}
 
@@ -1118,7 +1205,7 @@ mod tests {
 
 		let gas_left = {
 			let mut vm = interpreter(params, &ext);
-			test_finalize(vm.exec(&mut ext)).unwrap()
+			test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 		};
 
 		assert_eq!(ext.calls.len(), 1);
@@ -1140,7 +1227,7 @@ mod tests {
 
 		let err = {
 			let mut vm = interpreter(params, &ext);
-			test_finalize(vm.exec(&mut ext)).err().unwrap()
+			test_finalize(vm.exec(&mut ext).ok().unwrap()).err().unwrap()
 		};
 
 		assert_eq!(err, ::vm::Error::OutOfBounds);

ethcore/evm/src/tests.rs

@@ -39,7 +39,7 @@ fn test_add(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_eq!(gas_left, U256::from(79_988));
@@ -59,7 +59,7 @@ fn test_sha3(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_eq!(gas_left, U256::from(79_961));
@@ -79,7 +79,7 @@ fn test_address(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_eq!(gas_left, U256::from(79_995));
@@ -101,7 +101,7 @@ fn test_origin(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_eq!(gas_left, U256::from(79_995));
@@ -123,7 +123,7 @@ fn test_sender(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_eq!(gas_left, U256::from(79_995));
@@ -158,7 +158,7 @@ fn test_extcodecopy(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_eq!(gas_left, U256::from(79_935));
@@ -178,7 +178,7 @@ fn test_log_empty(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_eq!(gas_left, U256::from(99_619));
@@ -210,7 +210,7 @@ fn test_log_sender(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_eq!(gas_left, U256::from(98_974));
@@ -235,7 +235,7 @@ fn test_blockhash(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_eq!(gas_left, U256::from(79_974));
@@ -257,7 +257,7 @@ fn test_calldataload(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_eq!(gas_left, U256::from(79_991));
@@ -278,7 +278,7 @@ fn test_author(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_eq!(gas_left, U256::from(79_995));
@@ -298,7 +298,7 @@ fn test_timestamp(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_eq!(gas_left, U256::from(79_995));
@@ -318,7 +318,7 @@ fn test_number(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_eq!(gas_left, U256::from(79_995));
@@ -338,7 +338,7 @@ fn test_difficulty(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_eq!(gas_left, U256::from(79_995));
@@ -358,7 +358,7 @@ fn test_gas_limit(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_eq!(gas_left, U256::from(79_995));
@@ -376,7 +376,7 @@ fn test_mul(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_store(&ext, 0, "000000000000000000000000000000000000000000000000734349397b853383");
@@ -394,7 +394,7 @@ fn test_sub(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_store(&ext, 0, "0000000000000000000000000000000000000000000000000000012364ad0302");
@@ -412,7 +412,7 @@ fn test_div(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_store(&ext, 0, "000000000000000000000000000000000000000000000000000000000002e0ac");
@@ -430,7 +430,7 @@ fn test_div_zero(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_store(&ext, 0, "0000000000000000000000000000000000000000000000000000000000000000");
@@ -448,7 +448,7 @@ fn test_mod(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_store(&ext, 0, "0000000000000000000000000000000000000000000000000000000000076b4b");
@@ -467,7 +467,7 @@ fn test_smod(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_store(&ext, 0, "0000000000000000000000000000000000000000000000000000000000076b4b");
@@ -486,7 +486,7 @@ fn test_sdiv(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_store(&ext, 0, "000000000000000000000000000000000000000000000000000000000002e0ac");
@@ -505,7 +505,7 @@ fn test_exp(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_store(&ext, 0, "90fd23767b60204c3d6fc8aec9e70a42a3f127140879c133a20129a597ed0c59");
@@ -525,7 +525,7 @@ fn test_comparison(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_store(&ext, 0, "0000000000000000000000000000000000000000000000000000000000000000");
@@ -546,7 +546,7 @@ fn test_signed_comparison(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_store(&ext, 0, "0000000000000000000000000000000000000000000000000000000000000000");
@@ -567,7 +567,7 @@ fn test_bitops(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_store(&ext, 0, "00000000000000000000000000000000000000000000000000000000000000f0");
@@ -590,7 +590,7 @@ fn test_addmod_mulmod(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_store(&ext, 0, "0000000000000000000000000000000000000000000000000000000000000001");
@@ -611,7 +611,7 @@ fn test_byte(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_store(&ext, 0, "0000000000000000000000000000000000000000000000000000000000000000");
@@ -630,7 +630,7 @@ fn test_signextend(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_store(&ext, 0, "0000000000000000000000000000000000000000000000000000000000000fff");
@@ -650,7 +650,7 @@ fn test_badinstruction_int() {
 
 	let err = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap_err()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap_err()
 	};
 
 	match err {
@@ -670,7 +670,7 @@ fn test_pop(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_store(&ext, 0, "00000000000000000000000000000000000000000000000000000000000000f0");
@@ -690,7 +690,7 @@ fn test_extops(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_store(&ext, 0, "0000000000000000000000000000000000000000000000000000000000000004"); // PC / CALLDATASIZE
@@ -713,7 +713,7 @@ fn test_jumps(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_eq!(ext.sstore_clears, U256::from(ext.schedule().sstore_refund_gas));
@@ -741,7 +741,7 @@ fn test_calls(factory: super::Factory) {
 
 	let gas_left = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_set_contains(&ext.calls, &FakeCall {
@@ -782,7 +782,7 @@ fn test_create_in_staticcall(factory: super::Factory) {
 
 	let err = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap_err()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap_err()
 	};
 
 	assert_eq!(err, vm::Error::MutableCallInStaticContext);
@@ -1050,7 +1050,7 @@ fn push_two_pop_one_constantinople_test(factory: &super::Factory, opcode: u8, pu
 
 	let _ = {
 		let mut vm = factory.create(params, ext.schedule(), ext.depth());
-		test_finalize(vm.exec(&mut ext)).unwrap()
+		test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_store(&ext, 0, result);

ethcore/src/externalities.rs

@@ -25,9 +25,8 @@ use executive::*;
 use vm::{
 	self, ActionParams, ActionValue, EnvInfo, CallType, Schedule,
 	Ext, ContractCreateResult, MessageCallResult, CreateContractAddress,
-	ReturnData
+	ReturnData, TrapKind
 };
-use evm::FinalizationResult;
 use transaction::UNSIGNED_SENDER;
 use trace::{Tracer, VMTracer};
 
@@ -67,7 +66,8 @@ pub struct Externalities<'a, T: 'a, V: 'a, B: 'a> {
 	state: &'a mut State<B>,
 	env_info: &'a EnvInfo,
 	depth: usize,
-	origin_info: OriginInfo,
+	stack_depth: usize,
+	origin_info: &'a OriginInfo,
 	substate: &'a mut Substate,
 	machine: &'a Machine,
 	schedule: &'a Schedule,
@@ -87,7 +87,8 @@ impl<'a, T: 'a, V: 'a, B: 'a> Externalities<'a, T, V, B>
 		machine: &'a Machine,
 		schedule: &'a Schedule,
 		depth: usize,
-		origin_info: OriginInfo,
+		stack_depth: usize,
+		origin_info: &'a OriginInfo,
 		substate: &'a mut Substate,
 		output: OutputPolicy,
 		tracer: &'a mut T,
@@ -98,6 +99,7 @@ impl<'a, T: 'a, V: 'a, B: 'a> Externalities<'a, T, V, B>
 			state: state,
 			env_info: env_info,
 			depth: depth,
+			stack_depth: stack_depth,
 			origin_info: origin_info,
 			substate: substate,
 			machine: machine,
@@ -176,7 +178,7 @@ impl<'a, T: 'a, V: 'a, B: 'a> Ext for Externalities<'a, T, V, B>
 			};
 
 			let mut ex = Executive::new(self.state, self.env_info, self.machine, self.schedule);
-			let r = ex.call(params, self.substate, self.tracer, self.vm_tracer);
+			let r = ex.call_with_crossbeam(params, self.substate, self.stack_depth + 1, self.tracer, self.vm_tracer);
 			let output = match &r {
 				Ok(ref r) => H256::from(&r.return_data[..32]),
 				_ => H256::new(),
@@ -206,14 +208,15 @@ impl<'a, T: 'a, V: 'a, B: 'a> Ext for Externalities<'a, T, V, B>
 		gas: &U256,
 		value: &U256,
 		code: &[u8],
-		address_scheme: CreateContractAddress
-	) -> ContractCreateResult {
+		address_scheme: CreateContractAddress,
+		trap: bool,
+	) -> ::std::result::Result<ContractCreateResult, TrapKind> {
 		// create new contract address
 		let (address, code_hash) = match self.state.nonce(&self.origin_info.address) {
 			Ok(nonce) => contract_address(address_scheme, &self.origin_info.address, &nonce, &code),
 			Err(e) => {
 				debug!(target: "ext", "Database corruption encountered: {:?}", e);
-				return ContractCreateResult::Failed
+				return Ok(ContractCreateResult::Failed)
 			}
 		};
 
@@ -237,23 +240,19 @@ impl<'a, T: 'a, V: 'a, B: 'a> Ext for Externalities<'a, T, V, B>
 			if !self.schedule.keep_unsigned_nonce || params.sender != UNSIGNED_SENDER {
 				if let Err(e) = self.state.inc_nonce(&self.origin_info.address) {
 					debug!(target: "ext", "Database corruption encountered: {:?}", e);
-					return ContractCreateResult::Failed
+					return Ok(ContractCreateResult::Failed)
 				}
 			}
 		}
-		let mut ex = Executive::from_parent(self.state, self.env_info, self.machine, self.schedule, self.depth, self.static_flag);
+
+		if trap {
+			return Err(TrapKind::Create(params, address));
+		}
 
 		// TODO: handle internal error separately
-		match ex.create(params, self.substate, self.tracer, self.vm_tracer) {
-			Ok(FinalizationResult{ gas_left, apply_state: true, .. }) => {
-				self.substate.contracts_created.push(address.clone());
-				ContractCreateResult::Created(address, gas_left)
-			},
-			Ok(FinalizationResult{ gas_left, apply_state: false, return_data }) => {
-				ContractCreateResult::Reverted(gas_left, return_data)
-			},
-			_ => ContractCreateResult::Failed,
-		}
+		let mut ex = Executive::from_parent(self.state, self.env_info, self.machine, self.schedule, self.depth, self.static_flag);
+		let out = ex.create_with_crossbeam(params, self.substate, self.stack_depth + 1, self.tracer, self.vm_tracer);
+		Ok(into_contract_create_result(out, &address, self.substate))
 	}
 
 	fn call(
@@ -264,8 +263,9 @@ impl<'a, T: 'a, V: 'a, B: 'a> Ext for Externalities<'a, T, V, B>
 		value: Option<U256>,
 		data: &[u8],
 		code_address: &Address,
-		call_type: CallType
-	) -> MessageCallResult {
+		call_type: CallType,
+		trap: bool,
+	) -> ::std::result::Result<MessageCallResult, TrapKind> {
 		trace!(target: "externalities", "call");
 
 		let code_res = self.state.code(code_address)
@@ -273,7 +273,7 @@ impl<'a, T: 'a, V: 'a, B: 'a> Ext for Externalities<'a, T, V, B>
 
 		let (code, code_hash) = match code_res {
 			Ok((code, hash)) => (code, hash),
-			Err(_) => return MessageCallResult::Failed,
+			Err(_) => return Ok(MessageCallResult::Failed),
 		};
 
 		let mut params = ActionParams {
@@ -295,13 +295,13 @@ impl<'a, T: 'a, V: 'a, B: 'a> Ext for Externalities<'a, T, V, B>
 			params.value = ActionValue::Transfer(value);
 		}
 
-		let mut ex = Executive::from_parent(self.state, self.env_info, self.machine, self.schedule, self.depth, self.static_flag);
-
-		match ex.call(params, self.substate, self.tracer, self.vm_tracer) {
-			Ok(FinalizationResult{ gas_left, return_data, apply_state: true }) => MessageCallResult::Success(gas_left, return_data),
-			Ok(FinalizationResult{ gas_left, return_data, apply_state: false }) => MessageCallResult::Reverted(gas_left, return_data),
-			_ => MessageCallResult::Failed
+		if trap {
+			return Err(TrapKind::Call(params));
 		}
+
+		let mut ex = Executive::from_parent(self.state, self.env_info, self.machine, self.schedule, self.depth, self.static_flag);
+		let out = ex.call_with_crossbeam(params, self.substate, self.stack_depth + 1, self.tracer, self.vm_tracer);
+		Ok(into_message_call_result(out))
 	}
 
 	fn extcode(&self, address: &Address) -> vm::Result<Option<Arc<Bytes>>> {
@@ -406,12 +406,12 @@ impl<'a, T: 'a, V: 'a, B: 'a> Ext for Externalities<'a, T, V, B>
 		self.vm_tracer.trace_next_instruction(pc, instruction, current_gas)
 	}
 
-	fn trace_prepare_execute(&mut self, pc: usize, instruction: u8, gas_cost: U256) {
-		self.vm_tracer.trace_prepare_execute(pc, instruction, gas_cost)
+	fn trace_prepare_execute(&mut self, pc: usize, instruction: u8, gas_cost: U256, mem_written: Option<(usize, usize)>, store_written: Option<(U256, U256)>) {
+		self.vm_tracer.trace_prepare_execute(pc, instruction, gas_cost, mem_written, store_written)
 	}
 
-	fn trace_executed(&mut self, gas_used: U256, stack_push: &[U256], mem_diff: Option<(usize, &[u8])>, store_diff: Option<(U256, U256)>) {
-		self.vm_tracer.trace_executed(gas_used, stack_push, mem_diff, store_diff)
+	fn trace_executed(&mut self, gas_used: U256, stack_push: &[U256], mem: &[u8]) {
+		self.vm_tracer.trace_executed(gas_used, stack_push, mem)
 	}
 }
 
@@ -480,8 +480,9 @@ mod tests {
 		let state = &mut setup.state;
 		let mut tracer = NoopTracer;
 		let mut vm_tracer = NoopVMTracer;
+		let origin_info = get_test_origin();
 
-		let ext = Externalities::new(state, &setup.env_info, &setup.machine, &setup.schedule, 0, get_test_origin(), &mut setup.sub_state, OutputPolicy::InitContract, &mut tracer, &mut vm_tracer, false);
+		let ext = Externalities::new(state, &setup.env_info, &setup.machine, &setup.schedule, 0, 0, &origin_info, &mut setup.sub_state, OutputPolicy::InitContract, &mut tracer, &mut vm_tracer, false);
 
 		assert_eq!(ext.env_info().number, 100);
 	}
@@ -492,8 +493,9 @@ mod tests {
 		let state = &mut setup.state;
 		let mut tracer = NoopTracer;
 		let mut vm_tracer = NoopVMTracer;
+		let origin_info = get_test_origin();
 
-		let mut ext = Externalities::new(state, &setup.env_info, &setup.machine, &setup.schedule, 0, get_test_origin(), &mut setup.sub_state, OutputPolicy::InitContract, &mut tracer, &mut vm_tracer, false);
+		let mut ext = Externalities::new(state, &setup.env_info, &setup.machine, &setup.schedule, 0, 0, &origin_info, &mut setup.sub_state, OutputPolicy::InitContract, &mut tracer, &mut vm_tracer, false);
 
 		let hash = ext.blockhash(&"0000000000000000000000000000000000000000000000000000000000120000".parse::<U256>().unwrap());
 
@@ -516,8 +518,9 @@ mod tests {
 		let state = &mut setup.state;
 		let mut tracer = NoopTracer;
 		let mut vm_tracer = NoopVMTracer;
+		let origin_info = get_test_origin();
 
-		let mut ext = Externalities::new(state, &setup.env_info, &setup.machine, &setup.schedule, 0, get_test_origin(), &mut setup.sub_state, OutputPolicy::InitContract, &mut tracer, &mut vm_tracer, false);
+		let mut ext = Externalities::new(state, &setup.env_info, &setup.machine, &setup.schedule, 0, 0, &origin_info, &mut setup.sub_state, OutputPolicy::InitContract, &mut tracer, &mut vm_tracer, false);
 
 		let hash = ext.blockhash(&"0000000000000000000000000000000000000000000000000000000000120000".parse::<U256>().unwrap());
 
@@ -531,8 +534,9 @@ mod tests {
 		let state = &mut setup.state;
 		let mut tracer = NoopTracer;
 		let mut vm_tracer = NoopVMTracer;
+		let origin_info = get_test_origin();
 
-		let mut ext = Externalities::new(state, &setup.env_info, &setup.machine, &setup.schedule, 0, get_test_origin(), &mut setup.sub_state, OutputPolicy::InitContract, &mut tracer, &mut vm_tracer, false);
+		let mut ext = Externalities::new(state, &setup.env_info, &setup.machine, &setup.schedule, 0, 0, &origin_info, &mut setup.sub_state, OutputPolicy::InitContract, &mut tracer, &mut vm_tracer, false);
 
 		// this should panic because we have no balance on any account
 		ext.call(
@@ -542,8 +546,9 @@ mod tests {
 			Some("0000000000000000000000000000000000000000000000000000000000150000".parse::<U256>().unwrap()),
 			&[],
 			&Address::new(),
-			CallType::Call
-		);
+			CallType::Call,
+			false,
+		).ok().unwrap();
 	}
 
 	#[test]
@@ -555,9 +560,10 @@ mod tests {
 		let state = &mut setup.state;
 		let mut tracer = NoopTracer;
 		let mut vm_tracer = NoopVMTracer;
+		let origin_info = get_test_origin();
 
 		{
-			let mut ext = Externalities::new(state, &setup.env_info, &setup.machine, &setup.schedule, 0, get_test_origin(), &mut setup.sub_state, OutputPolicy::InitContract, &mut tracer, &mut vm_tracer, false);
+			let mut ext = Externalities::new(state, &setup.env_info, &setup.machine, &setup.schedule, 0, 0, &origin_info, &mut setup.sub_state, OutputPolicy::InitContract, &mut tracer, &mut vm_tracer, false);
 			ext.log(log_topics, &log_data).unwrap();
 		}
 
@@ -572,9 +578,10 @@ mod tests {
 		let state = &mut setup.state;
 		let mut tracer = NoopTracer;
 		let mut vm_tracer = NoopVMTracer;
+		let origin_info = get_test_origin();
 
 		{
-			let mut ext = Externalities::new(state, &setup.env_info, &setup.machine, &setup.schedule, 0, get_test_origin(), &mut setup.sub_state, OutputPolicy::InitContract, &mut tracer, &mut vm_tracer, false);
+			let mut ext = Externalities::new(state, &setup.env_info, &setup.machine, &setup.schedule, 0, 0, &origin_info, &mut setup.sub_state, OutputPolicy::InitContract, &mut tracer, &mut vm_tracer, false);
 			ext.suicide(refund_account).unwrap();
 		}
 
@@ -589,11 +596,12 @@ mod tests {
 		let state = &mut setup.state;
 		let mut tracer = NoopTracer;
 		let mut vm_tracer = NoopVMTracer;
+		let origin_info = get_test_origin();
 
 		let address = {
-			let mut ext = Externalities::new(state, &setup.env_info, &setup.machine, &setup.schedule, 0, get_test_origin(), &mut setup.sub_state, OutputPolicy::InitContract, &mut tracer, &mut vm_tracer, false);
-			match ext.create(&U256::max_value(), &U256::zero(), &[], CreateContractAddress::FromSenderAndNonce) {
-				ContractCreateResult::Created(address, _) => address,
+			let mut ext = Externalities::new(state, &setup.env_info, &setup.machine, &setup.schedule, 0, 0, &origin_info, &mut setup.sub_state, OutputPolicy::InitContract, &mut tracer, &mut vm_tracer, false);
+			match ext.create(&U256::max_value(), &U256::zero(), &[], CreateContractAddress::FromSenderAndNonce, false) {
+				Ok(ContractCreateResult::Created(address, _)) => address,
 				_ => panic!("Test create failed; expected Created, got Failed/Reverted."),
 			}
 		};
@@ -609,12 +617,13 @@ mod tests {
 		let state = &mut setup.state;
 		let mut tracer = NoopTracer;
 		let mut vm_tracer = NoopVMTracer;
+		let origin_info = get_test_origin();
 
 		let address = {
-			let mut ext = Externalities::new(state, &setup.env_info, &setup.machine, &setup.schedule, 0, get_test_origin(), &mut setup.sub_state, OutputPolicy::InitContract, &mut tracer, &mut vm_tracer, false);
+			let mut ext = Externalities::new(state, &setup.env_info, &setup.machine, &setup.schedule, 0, 0, &origin_info, &mut setup.sub_state, OutputPolicy::InitContract, &mut tracer, &mut vm_tracer, false);
 
-			match ext.create(&U256::max_value(), &U256::zero(), &[], CreateContractAddress::FromSenderSaltAndCodeHash(H256::default())) {
-				ContractCreateResult::Created(address, _) => address,
+			match ext.create(&U256::max_value(), &U256::zero(), &[], CreateContractAddress::FromSenderSaltAndCodeHash(H256::default()), false) {
+				Ok(ContractCreateResult::Created(address, _)) => address,
 				_ => panic!("Test create failed; expected Created, got Failed/Reverted."),
 			}
 		};

ethcore/src/factory.rs

@@ -18,7 +18,7 @@ use trie::TrieFactory;
 use ethtrie::RlpCodec;
 use account_db::Factory as AccountFactory;
 use evm::{Factory as EvmFactory, VMType};
-use vm::{Vm, ActionParams, Schedule};
+use vm::{Exec, ActionParams, Schedule};
 use wasm::WasmInterpreter;
 use keccak_hasher::KeccakHasher;
 
@@ -31,7 +31,7 @@ pub struct VmFactory {
 }
 
 impl VmFactory {
-	pub fn create(&self, params: ActionParams, schedule: &Schedule, depth: usize) -> Box<Vm> {
+	pub fn create(&self, params: ActionParams, schedule: &Schedule, depth: usize) -> Box<Exec> {
 		if schedule.wasm.is_some() && params.code.as_ref().map_or(false, |code| code.len() > 4 && &code[0..4] == WASM_MAGIC_NUMBER) {
 			Box::new(WasmInterpreter::new(params))
 		} else {

ethcore/src/json_tests/executive.rs

@@ -88,7 +88,7 @@ impl<'a, T: 'a, V: 'a, B: 'a> TestExt<'a, T, V, B>
 		machine: &'a Machine,
 		schedule: &'a Schedule,
 		depth: usize,
-		origin_info: OriginInfo,
+		origin_info: &'a OriginInfo,
 		substate: &'a mut Substate,
 		output: OutputPolicy,
 		address: Address,
@@ -98,7 +98,7 @@ impl<'a, T: 'a, V: 'a, B: 'a> TestExt<'a, T, V, B>
 		let static_call = false;
 		Ok(TestExt {
 			nonce: state.nonce(&address)?,
-			ext: Externalities::new(state, info, machine, schedule, depth, origin_info, substate, output, tracer, vm_tracer, static_call),
+			ext: Externalities::new(state, info, machine, schedule, depth, 0, origin_info, substate, output, tracer, vm_tracer, static_call),
 			callcreates: vec![],
 			sender: address,
 		})
@@ -140,7 +140,14 @@ impl<'a, T: 'a, V: 'a, B: 'a> Ext for TestExt<'a, T, V, B>
 		self.ext.blockhash(number)
 	}
 
-	fn create(&mut self, gas: &U256, value: &U256, code: &[u8], address: CreateContractAddress) -> ContractCreateResult {
+	fn create(
+		&mut self,
+		gas: &U256,
+		value: &U256,
+		code: &[u8],
+		address: CreateContractAddress,
+		_trap: bool
+	) -> Result<ContractCreateResult, vm::TrapKind> {
 		self.callcreates.push(CallCreate {
 			data: code.to_vec(),
 			destination: None,
@@ -148,25 +155,27 @@ impl<'a, T: 'a, V: 'a, B: 'a> Ext for TestExt<'a, T, V, B>
 			value: *value
 		});
 		let contract_address = contract_address(address, &self.sender, &self.nonce, &code).0;
-		ContractCreateResult::Created(contract_address, *gas)
+		Ok(ContractCreateResult::Created(contract_address, *gas))
 	}
 
-	fn call(&mut self,
+	fn call(
+		&mut self,
 		gas: &U256,
 		_sender_address: &Address,
 		receive_address: &Address,
 		value: Option<U256>,
 		data: &[u8],
 		_code_address: &Address,
-		_call_type: CallType
-	) -> MessageCallResult {
+		_call_type: CallType,
+		_trap: bool
+	) -> Result<MessageCallResult, vm::TrapKind> {
 		self.callcreates.push(CallCreate {
 			data: data.to_vec(),
 			destination: Some(receive_address.clone()),
 			gas_limit: *gas,
 			value: value.unwrap()
 		});
-		MessageCallResult::Success(*gas, ReturnData::empty())
+		Ok(MessageCallResult::Success(*gas, ReturnData::empty()))
 	}
 
 	fn extcode(&self, address: &Address) -> vm::Result<Option<Arc<Bytes>>>  {
@@ -270,6 +279,7 @@ fn do_json_test_for<H: FnMut(&str, HookType)>(vm_type: &VMType, json_data: &[u8]
 		let mut tracer = NoopTracer;
 		let mut vm_tracer = NoopVMTracer;
 		let vm_factory = state.vm_factory();
+		let origin_info = OriginInfo::from(&params);
 
 		// execute
 		let (res, callcreates) = {
@@ -280,7 +290,7 @@ fn do_json_test_for<H: FnMut(&str, HookType)>(vm_type: &VMType, json_data: &[u8]
 				&machine,
 				&schedule,
 				0,
-				OriginInfo::from(&params),
+				&origin_info,
 				&mut substate,
 				OutputPolicy::Return,
 				params.address.clone(),
@@ -288,7 +298,7 @@ fn do_json_test_for<H: FnMut(&str, HookType)>(vm_type: &VMType, json_data: &[u8]
 				&mut vm_tracer,
 			));
 			let mut evm = vm_factory.create(params, &schedule, 0);
-			let res = evm.exec(&mut ex);
+			let res = evm.exec(&mut ex).ok().expect("TestExt never trap; resume error never happens; qed");
 			// a return in finalize will not alter callcreates
 			let callcreates = ex.callcreates.clone();
 			(res.finalize(ex), callcreates)

ethcore/src/trace/db.rs

@@ -15,7 +15,7 @@
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
 //! Trace database.
-use std::collections::{HashMap, VecDeque};
+use std::collections::HashMap;
 use std::sync::Arc;
 use blockchain::{BlockChainDB};
 use heapsize::HeapSizeOf;
@@ -227,13 +227,12 @@ impl<T> TraceDatabase for TraceDB<T> where T: DatabaseExtras {
 	}
 
 	fn trace(&self, block_number: BlockNumber, tx_position: usize, trace_position: Vec<usize>) -> Option<LocalizedTrace> {
-		let trace_position_deq = VecDeque::from(trace_position);
 		self.extras.block_hash(block_number)
 			.and_then(|block_hash| self.transactions_traces(&block_hash)
 				.and_then(|traces| traces.into_iter().nth(tx_position))
 				.map(Into::<Vec<FlatTrace>>::into)
 				// this may and should be optimized
-				.and_then(|traces| traces.into_iter().find(|trace| trace.trace_address == trace_position_deq))
+				.and_then(|traces| traces.into_iter().find(|trace| trace.trace_address == trace_position))
 				.map(|trace| {
 					let tx_hash = self.extras.transaction_hash(block_number, tx_position)
 						.expect("Expected to find transaction hash. Database is probably corrupted");

ethcore/src/trace/executive_tracer.rs

@@ -17,159 +17,175 @@
 //! Simple executive tracer.
 
 use ethereum_types::{U256, Address};
-use vm::ActionParams;
+use vm::{Error as VmError, ActionParams};
 use trace::trace::{Call, Create, Action, Res, CreateResult, CallResult, VMTrace, VMOperation, VMExecutedOperation, MemoryDiff, StorageDiff, Suicide, Reward, RewardType};
-use trace::{Tracer, VMTracer, FlatTrace, TraceError};
+use trace::{Tracer, VMTracer, FlatTrace};
 
 /// Simple executive tracer. Traces all calls and creates. Ignores delegatecalls.
 #[derive(Default)]
 pub struct ExecutiveTracer {
 	traces: Vec<FlatTrace>,
-}
-
-fn top_level_subtraces(traces: &[FlatTrace]) -> usize {
-	traces.iter().filter(|t| t.trace_address.is_empty()).count()
-}
-
-fn prefix_subtrace_addresses(mut traces: Vec<FlatTrace>) -> Vec<FlatTrace> {
-	// input traces are expected to be ordered like
-	// []
-	// [0]
-	// [0, 0]
-	// [0, 1]
-	// []
-	// [0]
-	//
-	// so they can be transformed to
-	//
-	// [0]
-	// [0, 0]
-	// [0, 0, 0]
-	// [0, 0, 1]
-	// [1]
-	// [1, 0]
-	let mut current_subtrace_index = 0;
-	let mut first = true;
-	for trace in &mut traces {
-		match (first, trace.trace_address.is_empty()) {
-			(true, _) => first = false,
-			(_, true) => current_subtrace_index += 1,
-			_ => {}
-		}
-		trace.trace_address.push_front(current_subtrace_index);
-	}
-	traces
-}
-
-#[test]
-fn should_prefix_address_properly() {
-	use super::trace::{Action, Res, Suicide};
-
-	let f = |v: Vec<usize>| FlatTrace {
-		action: Action::Suicide(Suicide {
-			address: Default::default(),
-			balance: Default::default(),
-			refund_address: Default::default(),
-		}),
-		result: Res::None,
-		subtraces: 0,
-		trace_address: v.into_iter().collect(),
-	};
-	let t = vec![vec![], vec![0], vec![0, 0], vec![0], vec![], vec![], vec![0], vec![]].into_iter().map(&f).collect();
-	let t = prefix_subtrace_addresses(t);
-	assert_eq!(t, vec![vec![0], vec![0, 0], vec![0, 0, 0], vec![0, 0], vec![1], vec![2], vec![2, 0], vec![3]].into_iter().map(&f).collect::<Vec<_>>());
+	index_stack: Vec<usize>,
+	vecindex_stack: Vec<usize>,
+	sublen_stack: Vec<usize>,
+	skip_one: bool,
 }
 
 impl Tracer for ExecutiveTracer {
 	type Output = FlatTrace;
 
-	fn prepare_trace_call(&self, params: &ActionParams) -> Option<Call> {
-		Some(Call::from(params.clone()))
-	}
+	fn prepare_trace_call(&mut self, params: &ActionParams, depth: usize, is_builtin: bool) {
+		assert!(!self.skip_one, "skip_one is used only for builtin contracts that do not have subsequent calls; in prepare_trace_call it cannot be true; qed");
 
-	fn prepare_trace_create(&self, params: &ActionParams) -> Option<Create> {
-		Some(Create::from(params.clone()))
-	}
+		if depth != 0 && is_builtin && params.value.value() == U256::zero() {
+			self.skip_one = true;
+			return;
+		}
+
+		if let Some(parentlen) = self.sublen_stack.last_mut() {
+			*parentlen += 1;
+		}
 
-	fn trace_call(&mut self, call: Option<Call>, gas_used: U256, output: &[u8], subs: Vec<FlatTrace>) {
 		let trace = FlatTrace {
-			trace_address: Default::default(),
-			subtraces: top_level_subtraces(&subs),
-			action: Action::Call(call.expect("self.prepare_trace_call().is_some(): so we must be tracing: qed")),
+			trace_address: self.index_stack.clone(),
+			subtraces: self.sublen_stack.last().cloned().unwrap_or(0),
+			action: Action::Call(Call::from(params.clone())),
 			result: Res::Call(CallResult {
-				gas_used: gas_used,
-				output: output.into()
+				gas_used: U256::zero(),
+				output: Vec::new()
 			}),
 		};
-		debug!(target: "trace", "Traced call {:?}", trace);
+		self.vecindex_stack.push(self.traces.len());
 		self.traces.push(trace);
-		self.traces.extend(prefix_subtrace_addresses(subs));
+		self.index_stack.push(0);
+		self.sublen_stack.push(0);
 	}
 
-	fn trace_create(&mut self, create: Option<Create>, gas_used: U256, code: &[u8], address: Address, subs: Vec<FlatTrace>) {
+	fn prepare_trace_create(&mut self, params: &ActionParams) {
+		assert!(!self.skip_one, "skip_one is used only for builtin contracts that do not have subsequent calls; in prepare_trace_create it cannot be true; qed");
+
+		if let Some(parentlen) = self.sublen_stack.last_mut() {
+			*parentlen += 1;
+		}
+
 		let trace = FlatTrace {
-			subtraces: top_level_subtraces(&subs),
-			action: Action::Create(create.expect("self.prepare_trace_create().is_some(): so we must be tracing: qed")),
+			trace_address: self.index_stack.clone(),
+			subtraces: self.sublen_stack.last().cloned().unwrap_or(0),
+			action: Action::Create(Create::from(params.clone())),
 			result: Res::Create(CreateResult {
-				gas_used: gas_used,
-				code: code.into(),
-				address: address
+				gas_used: U256::zero(),
+				code: Vec::new(),
+				address: Address::default(),
 			}),
-			trace_address: Default::default(),
 		};
-		debug!(target: "trace", "Traced create {:?}", trace);
+		self.vecindex_stack.push(self.traces.len());
 		self.traces.push(trace);
-		self.traces.extend(prefix_subtrace_addresses(subs));
+		self.index_stack.push(0);
+		self.sublen_stack.push(0);
 	}
 
-	fn trace_failed_call(&mut self, call: Option<Call>, subs: Vec<FlatTrace>, error: TraceError) {
-		let trace = FlatTrace {
-			trace_address: Default::default(),
-			subtraces: top_level_subtraces(&subs),
-			action: Action::Call(call.expect("self.prepare_trace_call().is_some(): so we must be tracing: qed")),
-			result: Res::FailedCall(error),
-		};
-		debug!(target: "trace", "Traced failed call {:?}", trace);
-		self.traces.push(trace);
-		self.traces.extend(prefix_subtrace_addresses(subs));
+	fn done_trace_call(&mut self, gas_used: U256, output: &[u8]) {
+		if self.skip_one {
+			self.skip_one = false;
+			return;
+		}
+
+		let vecindex = self.vecindex_stack.pop().expect("Executive invoked prepare_trace_call before this function; vecindex_stack is never empty; qed");
+		let sublen = self.sublen_stack.pop().expect("Executive invoked prepare_trace_call before this function; sublen_stack is never empty; qed");
+		self.index_stack.pop();
+
+		self.traces[vecindex].result = Res::Call(CallResult {
+			gas_used,
+			output: output.into(),
+		});
+		self.traces[vecindex].subtraces = sublen;
+
+		if let Some(index) = self.index_stack.last_mut() {
+			*index += 1;
+		}
 	}
 
-	fn trace_failed_create(&mut self, create: Option<Create>, subs: Vec<FlatTrace>, error: TraceError) {
-		let trace = FlatTrace {
-			subtraces: top_level_subtraces(&subs),
-			action: Action::Create(create.expect("self.prepare_trace_create().is_some(): so we must be tracing: qed")),
-			result: Res::FailedCreate(error),
-			trace_address: Default::default(),
+	fn done_trace_create(&mut self, gas_used: U256, code: &[u8], address: Address) {
+		assert!(!self.skip_one, "skip_one is only set with prepare_trace_call for builtin contracts with no subsequent calls; skip_one cannot be true after the same level prepare_trace_create; qed");
+
+		let vecindex = self.vecindex_stack.pop().expect("Executive invoked prepare_trace_create before this function; vecindex_stack is never empty; qed");
+		let sublen = self.sublen_stack.pop().expect("Executive invoked prepare_trace_create before this function; sublen_stack is never empty; qed");
+		self.index_stack.pop();
+
+		self.traces[vecindex].result = Res::Create(CreateResult {
+			gas_used, address,
+			code: code.into(),
+		});
+		self.traces[vecindex].subtraces = sublen;
+
+		if let Some(index) = self.index_stack.last_mut() {
+			*index += 1;
+		}
+	}
+
+	fn done_trace_failed(&mut self, error: &VmError) {
+		if self.skip_one {
+			self.skip_one = false;
+			return;
+		}
+
+		let vecindex = self.vecindex_stack.pop().expect("Executive invoked prepare_trace_create/call before this function; vecindex_stack is never empty; qed");
+		let sublen = self.sublen_stack.pop().expect("Executive invoked prepare_trace_create/call before this function; vecindex_stack is never empty; qed");
+		self.index_stack.pop();
+
+		let is_create = match self.traces[vecindex].action {
+			Action::Create(_) => true,
+			_ => false,
 		};
-		debug!(target: "trace", "Traced failed create {:?}", trace);
-		self.traces.push(trace);
-		self.traces.extend(prefix_subtrace_addresses(subs));
+
+		if is_create {
+			self.traces[vecindex].result = Res::FailedCreate(error.into());
+		} else {
+			self.traces[vecindex].result = Res::FailedCall(error.into());
+		}
+		self.traces[vecindex].subtraces = sublen;
+
+		if let Some(index) = self.index_stack.last_mut() {
+			*index += 1;
+		}
 	}
 
 	fn trace_suicide(&mut self, address: Address, balance: U256, refund_address: Address) {
+		if let Some(parentlen) = self.sublen_stack.last_mut() {
+			*parentlen += 1;
+		}
+
 		let trace = FlatTrace {
 			subtraces: 0,
 			action: Action::Suicide(Suicide { address, refund_address, balance } ),
 			result: Res::None,
-			trace_address: Default::default(),
+			trace_address: self.index_stack.clone(),
 		};
 		debug!(target: "trace", "Traced suicide {:?}", trace);
 		self.traces.push(trace);
+
+		if let Some(index) = self.index_stack.last_mut() {
+			*index += 1;
+		}
 	}
 
 	fn trace_reward(&mut self, author: Address, value: U256, reward_type: RewardType) {
+		if let Some(parentlen) = self.sublen_stack.last_mut() {
+			*parentlen += 1;
+		}
+
 		let trace = FlatTrace {
 			subtraces: 0,
 			action: Action::Reward(Reward { author, value, reward_type } ),
 			result: Res::None,
-			trace_address: Default::default(),
+			trace_address: self.index_stack.clone(),
 		};
 		debug!(target: "trace", "Traced reward {:?}", trace);
 		self.traces.push(trace);
-	}
 
-	fn subtracer(&self) -> Self {
-		ExecutiveTracer::default()
+		if let Some(index) = self.index_stack.last_mut() {
+			*index += 1;
+		}
 	}
 
 	fn drain(self) -> Vec<FlatTrace> {
@@ -180,6 +196,9 @@ impl Tracer for ExecutiveTracer {
 /// Simple VM tracer. Traces all operations.
 pub struct ExecutiveVMTracer {
 	data: VMTrace,
+	depth: usize,
+	last_mem_written: Option<(usize, usize)>,
+	last_store_written: Option<(U256, U256)>,
 }
 
 impl ExecutiveVMTracer {
@@ -191,7 +210,18 @@ impl ExecutiveVMTracer {
 				code: vec![],
 				operations: vec![Default::default()],	// prefill with a single entry so that prepare_subtrace can get the parent_step
 				subs: vec![],
-			}
+			},
+			depth: 0,
+			last_mem_written: None,
+			last_store_written: None,
+		}
+	}
+
+	fn with_trace_in_depth<F: Fn(&mut VMTrace)>(trace: &mut VMTrace, depth: usize, f: F) {
+		if depth == 0 {
+			f(trace);
+		} else {
+			Self::with_trace_in_depth(trace.subs.last_mut().expect("self.depth is incremented with prepare_subtrace; a subtrace is always pushed; self.depth cannot be greater than subtrace stack; qed"), depth - 1, f);
 		}
 	}
 }
@@ -201,37 +231,77 @@ impl VMTracer for ExecutiveVMTracer {
 
 	fn trace_next_instruction(&mut self, _pc: usize, _instruction: u8, _current_gas: U256) -> bool { true }
 
-	fn trace_prepare_execute(&mut self, pc: usize, instruction: u8, gas_cost: U256) {
-		self.data.operations.push(VMOperation {
-			pc: pc,
-			instruction: instruction,
-			gas_cost: gas_cost,
-			executed: None,
+	fn trace_prepare_execute(&mut self, pc: usize, instruction: u8, gas_cost: U256, mem_written: Option<(usize, usize)>, store_written: Option<(U256, U256)>) {
+		Self::with_trace_in_depth(&mut self.data, self.depth, move |trace| {
+			trace.operations.push(VMOperation {
+				pc: pc,
+				instruction: instruction,
+				gas_cost: gas_cost,
+				executed: None,
+			});
+		});
+		self.last_mem_written = mem_written;
+		self.last_store_written = store_written;
+	}
+
+	fn trace_executed(&mut self, gas_used: U256, stack_push: &[U256], mem: &[u8]) {
+		let mem_diff = self.last_mem_written.take().map(|(o, s)| (o, &(mem[o..o+s])));
+		let store_diff = self.last_store_written.take();
+		Self::with_trace_in_depth(&mut self.data, self.depth, move |trace| {
+			let ex = VMExecutedOperation {
+				gas_used: gas_used,
+				stack_push: stack_push.iter().cloned().collect(),
+				mem_diff: mem_diff.map(|(s, r)| MemoryDiff { offset: s, data: r.iter().cloned().collect() }),
+				store_diff: store_diff.map(|(l, v)| StorageDiff { location: l, value: v }),
+			};
+			trace.operations.last_mut().expect("trace_executed is always called after a trace_prepare_execute; trace.operations cannot be empty; qed").executed = Some(ex);
 		});
 	}
 
-	fn trace_executed(&mut self, gas_used: U256, stack_push: &[U256], mem_diff: Option<(usize, &[u8])>, store_diff: Option<(U256, U256)>) {
-		let ex = VMExecutedOperation {
-			gas_used: gas_used,
-			stack_push: stack_push.iter().cloned().collect(),
-			mem_diff: mem_diff.map(|(s, r)| MemoryDiff{ offset: s, data: r.iter().cloned().collect() }),
-			store_diff: store_diff.map(|(l, v)| StorageDiff{ location: l, value: v }),
-		};
-		self.data.operations.last_mut().expect("trace_executed is always called after a trace_prepare_execute").executed = Some(ex);
+	fn prepare_subtrace(&mut self, code: &[u8]) {
+		Self::with_trace_in_depth(&mut self.data, self.depth, move |trace| {
+			let parent_step = trace.operations.len() - 1; // won't overflow since we must already have pushed an operation in trace_prepare_execute.
+			trace.subs.push(VMTrace {
+				parent_step,
+				code: code.to_vec(),
+				operations: vec![],
+				subs: vec![],
+			});
+		});
+		self.depth += 1;
 	}
 
-	fn prepare_subtrace(&self, code: &[u8]) -> Self {
-		ExecutiveVMTracer { data: VMTrace {
-			parent_step: self.data.operations.len() - 1,	// won't overflow since we must already have pushed an operation in trace_prepare_execute.
-			code: code.to_vec(),
-			operations: vec![],
-			subs: vec![],
-		}}
-	}
-
-	fn done_subtrace(&mut self, sub: Self) {
-		self.data.subs.push(sub.data);
+	fn done_subtrace(&mut self) {
+		self.depth -= 1;
 	}
 
 	fn drain(mut self) -> Option<VMTrace> { self.data.subs.pop() }
 }
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+
+	#[test]
+	fn should_prefix_address_properly() {
+		let mut tracer = ExecutiveTracer::default();
+
+		tracer.prepare_trace_call(&ActionParams::default(), 0, false);
+		tracer.prepare_trace_call(&ActionParams::default(), 1, false);
+		tracer.prepare_trace_call(&ActionParams::default(), 2, false);
+		tracer.done_trace_call(U256::zero(), &[]);
+		tracer.prepare_trace_call(&ActionParams::default(), 2, false);
+		tracer.done_trace_call(U256::zero(), &[]);
+		tracer.prepare_trace_call(&ActionParams::default(), 2, false);
+		tracer.done_trace_call(U256::zero(), &[]);
+		tracer.done_trace_call(U256::zero(), &[]);
+		tracer.done_trace_call(U256::zero(), &[]);
+
+		let drained = tracer.drain();
+		assert!(drained[0].trace_address.len() == 0);
+		assert_eq!(&drained[1].trace_address, &[0]);
+		assert_eq!(&drained[2].trace_address, &[0, 0]);
+		assert_eq!(&drained[3].trace_address, &[0, 1]);
+		assert_eq!(&drained[4].trace_address, &[0, 2]);
+	}
+}

ethcore/src/trace/mod.rs

@@ -38,8 +38,7 @@ pub use self::types::filter::{Filter, AddressesFilter};
 
 use ethereum_types::{H256, U256, Address};
 use kvdb::DBTransaction;
-use self::trace::{Call, Create};
-use vm::ActionParams;
+use vm::{Error as VmError, ActionParams};
 use header::BlockNumber;
 
 /// This trait is used by executive to build traces.
@@ -47,48 +46,20 @@ pub trait Tracer: Send {
 	/// Data returned when draining the Tracer.
 	type Output;
 
-	/// Prepares call trace for given params. Noop tracer should return None.
-	///
-	/// This is called before a call has been executed.
-	fn prepare_trace_call(&self, params: &ActionParams) -> Option<Call>;
+	/// Prepares call trace for given params. Would panic if prepare/done_trace are not balanced.
+	fn prepare_trace_call(&mut self, params: &ActionParams, depth: usize, is_builtin: bool);
 
-	/// Prepares create trace for given params. Noop tracer should return None.
-	///
-	/// This is called before a create has been executed.
-	fn prepare_trace_create(&self, params: &ActionParams) -> Option<Create>;
+	/// Prepares create trace for given params. Would panic if prepare/done_trace are not balanced.
+	fn prepare_trace_create(&mut self, params: &ActionParams);
 
-	/// Stores trace call info.
-	///
-	/// This is called after a call has completed successfully.
-	fn trace_call(
-		&mut self,
-		call: Option<Call>,
-		gas_used: U256,
-		output: &[u8],
-		subs: Vec<Self::Output>,
-	);
+	/// Finishes a successful call trace. Would panic if prepare/done_trace are not balanced.
+	fn done_trace_call(&mut self, gas_used: U256, output: &[u8]);
 
-	/// Stores trace create info.
-	///
-	/// This is called after a create has completed successfully.
-	fn trace_create(
-		&mut self,
-		create: Option<Create>,
-		gas_used: U256,
-		code: &[u8],
-		address: Address,
-		subs: Vec<Self::Output>
-	);
+	/// Finishes a successful create trace. Would panic if prepare/done_trace are not balanced.
+	fn done_trace_create(&mut self, gas_used: U256, code: &[u8], address: Address);
 
-	/// Stores failed call trace.
-	///
-	/// This is called after a call has completed erroneously.
-	fn trace_failed_call(&mut self, call: Option<Call>, subs: Vec<Self::Output>, error: TraceError);
-
-	/// Stores failed create trace.
-	///
-	/// This is called after a create has completed erroneously.
-	fn trace_failed_create(&mut self, create: Option<Create>, subs: Vec<Self::Output>, error: TraceError);
+	/// Finishes a failed trace. Would panic if prepare/done_trace are not balanced.
+	fn done_trace_failed(&mut self, error: &VmError);
 
 	/// Stores suicide info.
 	fn trace_suicide(&mut self, address: Address, balance: U256, refund_address: Address);
@@ -96,9 +67,6 @@ pub trait Tracer: Send {
 	/// Stores reward info.
 	fn trace_reward(&mut self, author: Address, value: U256, reward_type: RewardType);
 
-	/// Spawn subtracer which will be used to trace deeper levels of execution.
-	fn subtracer(&self) -> Self where Self: Sized;
-
 	/// Consumes self and returns all traces.
 	fn drain(self) -> Vec<Self::Output>;
 }
@@ -115,16 +83,16 @@ pub trait VMTracer: Send {
 	fn trace_next_instruction(&mut self, _pc: usize, _instruction: u8, _current_gas: U256) -> bool { false }
 
 	/// Trace the preparation to execute a single valid instruction.
-	fn trace_prepare_execute(&mut self, _pc: usize, _instruction: u8, _gas_cost: U256) {}
+	fn trace_prepare_execute(&mut self, _pc: usize, _instruction: u8, _gas_cost: U256, _mem_written: Option<(usize, usize)>, _store_written: Option<(U256, U256)>) {}
 
 	/// Trace the finalised execution of a single valid instruction.
-	fn trace_executed(&mut self, _gas_used: U256, _stack_push: &[U256], _mem_diff: Option<(usize, &[u8])>, _store_diff: Option<(U256, U256)>) {}
+	fn trace_executed(&mut self, _gas_used: U256, _stack_push: &[U256], _mem: &[u8]) {}
 
 	/// Spawn subtracer which will be used to trace deeper levels of execution.
-	fn prepare_subtrace(&self, code: &[u8]) -> Self where Self: Sized;
+	fn prepare_subtrace(&mut self, _code: &[u8]) {}
 
 	/// Finalize subtracer.
-	fn done_subtrace(&mut self, sub: Self) where Self: Sized;
+	fn done_subtrace(&mut self) {}
 
 	/// Consumes self and returns the VM trace.
 	fn drain(self) -> Option<Self::Output>;

ethcore/src/trace/noop_tracer.rs

@@ -17,9 +17,9 @@
 //! Nonoperative tracer.
 
 use ethereum_types::{U256, Address};
-use vm::ActionParams;
-use trace::{Tracer, VMTracer, FlatTrace, TraceError};
-use trace::trace::{Call, Create, VMTrace, RewardType};
+use vm::{Error as VmError, ActionParams};
+use trace::{Tracer, VMTracer, FlatTrace};
+use trace::trace::{VMTrace, RewardType};
 
 /// Nonoperative tracer. Does not trace anything.
 pub struct NoopTracer;
@@ -27,43 +27,14 @@ pub struct NoopTracer;
 impl Tracer for NoopTracer {
 	type Output = FlatTrace;
 
-	fn prepare_trace_call(&self, _: &ActionParams) -> Option<Call> {
-		None
-	}
-
-	fn prepare_trace_create(&self, _: &ActionParams) -> Option<Create> {
-		None
-	}
-
-	fn trace_call(&mut self, call: Option<Call>, _: U256, _: &[u8], _: Vec<FlatTrace>) {
-		assert!(call.is_none(), "self.prepare_trace_call().is_none(): so we can't be tracing: qed");
-	}
-
-	fn trace_create(&mut self, create: Option<Create>, _: U256, _: &[u8], _: Address, _: Vec<FlatTrace>) {
-		assert!(create.is_none(), "self.prepare_trace_create().is_none(): so we can't be tracing: qed");
-	}
-
-	fn trace_failed_call(&mut self, call: Option<Call>, _: Vec<FlatTrace>, _: TraceError) {
-		assert!(call.is_none(), "self.prepare_trace_call().is_none(): so we can't be tracing: qed");
-	}
-
-	fn trace_failed_create(&mut self, create: Option<Create>, _: Vec<FlatTrace>, _: TraceError) {
-		assert!(create.is_none(), "self.prepare_trace_create().is_none(): so we can't be tracing: qed");
-	}
-
-	fn trace_suicide(&mut self, _address: Address, _balance: U256, _refund_address: Address) {
-	}
-
-	fn trace_reward(&mut self, _: Address, _: U256, _: RewardType) {
-	}
-
-	fn subtracer(&self) -> Self {
-		NoopTracer
-	}
-
-	fn drain(self) -> Vec<FlatTrace> {
-		vec![]
-	}
+	fn prepare_trace_call(&mut self, _: &ActionParams, _: usize, _: bool) { }
+	fn prepare_trace_create(&mut self, _: &ActionParams) { }
+	fn done_trace_call(&mut self, _: U256, _: &[u8]) { }
+	fn done_trace_create(&mut self, _: U256, _: &[u8], _: Address) { }
+	fn done_trace_failed(&mut self, _: &VmError) { }
+	fn trace_suicide(&mut self, _: Address, _: U256, _: Address) { }
+	fn trace_reward(&mut self, _: Address, _: U256, _: RewardType) { }
+	fn drain(self) -> Vec<FlatTrace> { vec![] }
 }
 
 /// Nonoperative VM tracer. Does not trace anything.
@@ -72,15 +43,5 @@ pub struct NoopVMTracer;
 impl VMTracer for NoopVMTracer {
 	type Output = VMTrace;
 
-	fn trace_next_instruction(&mut self, _pc: usize, _instruction: u8, _current_gas: U256) -> bool { false }
-
-	fn trace_prepare_execute(&mut self, _pc: usize, _instruction: u8, _gas_cost: U256) {}
-
-	fn trace_executed(&mut self, _gas_used: U256, _stack_push: &[U256], _mem_diff: Option<(usize, &[u8])>, _store_diff: Option<(U256, U256)>) {}
-
-	fn prepare_subtrace(&self, _code: &[u8]) -> Self { NoopVMTracer }
-
-	fn done_subtrace(&mut self, _sub: Self) {}
-
 	fn drain(self) -> Option<VMTrace> { None }
 }

ethcore/src/trace/types/flat.rs

@@ -16,7 +16,6 @@
 
 //! Flat trace module
 
-use std::collections::VecDeque;
 use rlp::{Rlp, RlpStream, Decodable, Encodable, DecoderError};
 use heapsize::HeapSizeOf;
 use ethereum_types::Bloom;
@@ -36,7 +35,7 @@ pub struct FlatTrace {
 	/// Exact location of trace.
 	///
 	/// [index in root, index in first CALL, index in second CALL, ...]
-	pub trace_address: VecDeque<usize>,
+	pub trace_address: Vec<usize>,
 }
 
 impl FlatTrace {

ethcore/vm/src/error.rs

@@ -16,9 +16,23 @@
 
 //! VM errors module
 
+use ::{ResumeCall, ResumeCreate};
+use ethereum_types::Address;
+use action_params::ActionParams;
 use std::fmt;
 use ethtrie;
 
+#[derive(Debug)]
+pub enum TrapKind {
+	Call(ActionParams),
+	Create(ActionParams, Address),
+}
+
+pub enum TrapError<Call, Create> {
+	Call(ActionParams, Call),
+	Create(ActionParams, Address, Create),
+}
+
 /// VM errors.
 #[derive(Debug, Clone, PartialEq)]
 pub enum Error {
@@ -76,18 +90,13 @@ impl From<Box<ethtrie::TrieError>> for Error {
 		Error::Internal(format!("Internal error: {}", err))
 	}
 }
+
 impl From<ethtrie::TrieError> for Error {
 	fn from(err: ethtrie::TrieError) -> Self {
 		Error::Internal(format!("Internal error: {}", err))
 	}
 }
 
-// impl From<wasm::RuntimeError> for Error {
-// 	fn from(err: wasm::RuntimeError) -> Self {
-// 		Error::Wasm(format!("Runtime error: {:?}", err))
-// 	}
-// }
-
 impl fmt::Display for Error {
 	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 		use self::Error::*;
@@ -108,3 +117,7 @@ impl fmt::Display for Error {
 }
 
 pub type Result<T> = ::std::result::Result<T, Error>;
+pub type TrapResult<T, Call, Create> = ::std::result::Result<Result<T>, TrapError<Call, Create>>;
+
+pub type ExecTrapResult<T> = TrapResult<T, Box<ResumeCall>, Box<ResumeCreate>>;
+pub type ExecTrapError = TrapError<Box<ResumeCall>, Box<ResumeCreate>>;

ethcore/vm/src/ext.rs

@@ -23,8 +23,9 @@ use call_type::CallType;
 use env_info::EnvInfo;
 use schedule::Schedule;
 use return_data::ReturnData;
-use error::Result;
+use error::{Result, TrapKind};
 
+#[derive(Debug)]
 /// Result of externalities create function.
 pub enum ContractCreateResult {
 	/// Returned when creation was successfull.
@@ -37,6 +38,7 @@ pub enum ContractCreateResult {
 	Reverted(U256, ReturnData),
 }
 
+#[derive(Debug)]
 /// Result of externalities call function.
 pub enum MessageCallResult {
 	/// Returned when message call was successfull.
@@ -90,22 +92,31 @@ pub trait Ext {
 	/// Creates new contract.
 	///
 	/// Returns gas_left and contract address if contract creation was succesfull.
-	fn create(&mut self, gas: &U256, value: &U256, code: &[u8], address: CreateContractAddress) -> ContractCreateResult;
+	fn create(
+		&mut self,
+		gas: &U256,
+		value: &U256,
+		code: &[u8],
+		address: CreateContractAddress,
+		trap: bool,
+	) -> ::std::result::Result<ContractCreateResult, TrapKind>;
 
 	/// Message call.
 	///
 	/// Returns Err, if we run out of gas.
 	/// Otherwise returns call_result which contains gas left
 	/// and true if subcall was successfull.
-	fn call(&mut self,
+	fn call(
+		&mut self,
 		gas: &U256,
 		sender_address: &Address,
 		receive_address: &Address,
 		value: Option<U256>,
 		data: &[u8],
 		code_address: &Address,
-		call_type: CallType
-	) -> MessageCallResult;
+		call_type: CallType,
+		trap: bool
+	) -> ::std::result::Result<MessageCallResult, TrapKind>;
 
 	/// Returns code at given address
 	fn extcode(&self, address: &Address) -> Result<Option<Arc<Bytes>>>;
@@ -149,10 +160,10 @@ pub trait Ext {
 	fn trace_next_instruction(&mut self, _pc: usize, _instruction: u8, _current_gas: U256) -> bool { false }
 
 	/// Prepare to trace an operation. Passthrough for the VM trace.
-	fn trace_prepare_execute(&mut self, _pc: usize, _instruction: u8, _gas_cost: U256) {}
+	fn trace_prepare_execute(&mut self, _pc: usize, _instruction: u8, _gas_cost: U256, _mem_written: Option<(usize, usize)>, _store_written: Option<(U256, U256)>) {}
 
 	/// Trace the finalised execution of a single instruction.
-	fn trace_executed(&mut self, _gas_used: U256, _stack_push: &[U256], _mem_diff: Option<(usize, &[u8])>, _store_diff: Option<(U256, U256)>) {}
+	fn trace_executed(&mut self, _gas_used: U256, _stack_push: &[U256], _mem: &[u8]) {}
 
 	/// Check if running in static context.
 	fn is_static(&self) -> bool;

ethcore/vm/src/lib.rs

@@ -41,12 +41,24 @@ pub use env_info::{EnvInfo, LastHashes};
 pub use schedule::{Schedule, CleanDustMode, WasmCosts};
 pub use ext::{Ext, MessageCallResult, ContractCreateResult, CreateContractAddress};
 pub use return_data::{ReturnData, GasLeft};
-pub use error::{Error, Result};
+pub use error::{Error, Result, TrapResult, TrapError, TrapKind, ExecTrapResult, ExecTrapError};
 
 /// Virtual Machine interface
-pub trait Vm {
+pub trait Exec: Send {
 	/// This function should be used to execute transaction.
 	/// It returns either an error, a known amount of gas left, or parameters to be used
 	/// to compute the final gas left.
-	fn exec(&mut self, ext: &mut Ext) -> Result<GasLeft>;
+	fn exec(self: Box<Self>, ext: &mut Ext) -> ExecTrapResult<GasLeft>;
+}
+
+/// Resume call interface
+pub trait ResumeCall: Send {
+	/// Resume an execution for call, returns back the Vm interface.
+	fn resume_call(self: Box<Self>, result: MessageCallResult) -> Box<Exec>;
+}
+
+/// Resume create interface
+pub trait ResumeCreate: Send {
+	/// Resume an execution from create, returns back the Vm interface.
+	fn resume_create(self: Box<Self>, result: ContractCreateResult) -> Box<Exec>;
 }

ethcore/vm/src/tests.rs

@@ -25,6 +25,7 @@ use {
 	CreateContractAddress, Result, GasLeft,
 };
 use hash::keccak;
+use error::TrapKind;
 
 pub struct FakeLogEntry {
 	pub topics: Vec<H256>,
@@ -138,7 +139,14 @@ impl Ext for FakeExt {
 		self.blockhashes.get(number).unwrap_or(&H256::new()).clone()
 	}
 
-	fn create(&mut self, gas: &U256, value: &U256, code: &[u8], address: CreateContractAddress) -> ContractCreateResult {
+	fn create(
+		&mut self,
+		gas: &U256,
+		value: &U256,
+		code: &[u8],
+		address: CreateContractAddress,
+		_trap: bool,
+	) -> ::std::result::Result<ContractCreateResult, TrapKind> {
 		self.calls.insert(FakeCall {
 			call_type: FakeCallType::Create,
 			create_scheme: Some(address),
@@ -149,19 +157,21 @@ impl Ext for FakeExt {
 			data: code.to_vec(),
 			code_address: None
 		});
-		ContractCreateResult::Failed
+		// TODO: support traps in testing.
+		Ok(ContractCreateResult::Failed)
 	}
 
-	fn call(&mut self,
-			gas: &U256,
-			sender_address: &Address,
-			receive_address: &Address,
-			value: Option<U256>,
-			data: &[u8],
-			code_address: &Address,
-			_call_type: CallType
-		) -> MessageCallResult {
-
+	fn call(
+		&mut self,
+		gas: &U256,
+		sender_address: &Address,
+		receive_address: &Address,
+		value: Option<U256>,
+		data: &[u8],
+		code_address: &Address,
+		_call_type: CallType,
+		_trap: bool,
+	) -> ::std::result::Result<MessageCallResult, TrapKind> {
 		self.calls.insert(FakeCall {
 			call_type: FakeCallType::Call,
 			create_scheme: None,
@@ -172,7 +182,8 @@ impl Ext for FakeExt {
 			data: data.to_vec(),
 			code_address: Some(code_address.clone())
 		});
-		MessageCallResult::Success(*gas, ReturnData::empty())
+		// TODO: support traps in testing.
+		Ok(MessageCallResult::Success(*gas, ReturnData::empty()))
 	}
 
 	fn extcode(&self, address: &Address) -> Result<Option<Arc<Bytes>>> {

ethcore/wasm/run/src/runner.rs

@@ -16,7 +16,7 @@
 
 use fixture::{Fixture, Assert, CallLocator, Source};
 use wasm::WasmInterpreter;
-use vm::{self, Vm, GasLeft, ActionParams, ActionValue, ParamsType};
+use vm::{self, Exec, GasLeft, ActionParams, ActionValue, ParamsType};
 use vm::tests::FakeExt;
 use std::io::{self, Read};
 use std::{fs, path, fmt};
@@ -31,8 +31,8 @@ fn load_code<P: AsRef<path::Path>>(p: P) -> io::Result<Vec<u8>> {
 	Ok(result)
 }
 
-fn wasm_interpreter(params: ActionParams) -> WasmInterpreter {
-	WasmInterpreter::new(params)
+fn wasm_interpreter(params: ActionParams) -> Box<WasmInterpreter> {
+	Box::new(WasmInterpreter::new(params))
 }
 
 #[derive(Debug)]
@@ -131,7 +131,7 @@ pub fn construct(
 	params.params_type = ParamsType::Separate;
 
 	Ok(
-		match wasm_interpreter(params).exec(ext)? {
+		match wasm_interpreter(params).exec(ext).ok().expect("Wasm interpreter always calls with trap=false; trap never happens; qed")? {
 			GasLeft::Known(_) => Vec::new(),
 			GasLeft::NeedsReturn { data, .. } => data.to_vec(),
 		}
@@ -192,9 +192,9 @@ pub fn run_fixture(fixture: &Fixture) -> Vec<Fail> {
 		}
 	}
 
-	let mut interpreter = wasm_interpreter(params);
+	let interpreter = wasm_interpreter(params);
 
-	let interpreter_return = match interpreter.exec(&mut ext) {
+	let interpreter_return = match interpreter.exec(&mut ext).ok().expect("Wasm interpreter always calls with trap=false; trap never happens; qed") {
 		Ok(ret) => ret,
 		Err(e) => { return Fail::runtime(e); }
 	};

ethcore/wasm/src/lib.rs

@@ -91,9 +91,8 @@ enum ExecutionOutcome {
 	NotSpecial,
 }
 
-impl vm::Vm for WasmInterpreter {
-
-	fn exec(&mut self, ext: &mut vm::Ext) -> vm::Result<GasLeft> {
+impl WasmInterpreter {
+	pub fn run(self: Box<WasmInterpreter>, ext: &mut vm::Ext) -> vm::Result<GasLeft> {
 		let (module, data) = parser::payload(&self.params, ext.schedule().wasm())?;
 
 		let loaded_module = wasmi::Module::from_parity_wasm_module(module).map_err(Error::Interpreter)?;
@@ -190,3 +189,9 @@ impl vm::Vm for WasmInterpreter {
 		}
 	}
 }
+
+impl vm::Exec for WasmInterpreter {
+	fn exec(self: Box<WasmInterpreter>, ext: &mut vm::Ext) -> vm::ExecTrapResult<GasLeft> {
+		Ok(self.run(ext))
+	}
+}

ethcore/wasm/src/runtime.rs

@@ -450,7 +450,8 @@ impl<'a> Runtime<'a> {
 			&payload,
 			&address,
 			call_type,
-		);
+			false
+		).ok().expect("Trap is false; trap error will not happen; qed");
 
 		match call_result {
 			vm::MessageCallResult::Success(gas_left, data) => {
@@ -528,7 +529,7 @@ impl<'a> Runtime<'a> {
 			* U256::from(self.ext.schedule().wasm().opcodes_mul)
 			/ U256::from(self.ext.schedule().wasm().opcodes_div);
 
-		match self.ext.create(&gas_left, &endowment, &code, scheme) {
+		match self.ext.create(&gas_left, &endowment, &code, scheme, false).ok().expect("Trap is false; trap error will not happen; qed") {
 			vm::ContractCreateResult::Created(address, gas_left) => {
 				self.memory.set(result_ptr, &*address)?;
 				self.gas_counter = self.gas_limit -

ethcore/wasm/src/tests.rs

@@ -20,7 +20,7 @@ use byteorder::{LittleEndian, ByteOrder};
 use ethereum_types::{H256, U256, Address};
 
 use super::WasmInterpreter;
-use vm::{self, Vm, GasLeft, ActionParams, ActionValue, CreateContractAddress};
+use vm::{self, Exec, GasLeft, ActionParams, ActionValue, CreateContractAddress};
 use vm::tests::{FakeCall, FakeExt, FakeCallType};
 
 macro_rules! load_sample {
@@ -48,7 +48,7 @@ macro_rules! reqrep_test {
 			fake_ext.blockhashes = $block_hashes;
 
 			let mut interpreter = wasm_interpreter(params);
-			interpreter.exec(&mut fake_ext)
+			interpreter.exec(&mut fake_ext).ok().unwrap()
 				.map(|result| match result {
 					GasLeft::Known(_) => { panic!("Test is expected to return payload to check"); },
 					GasLeft::NeedsReturn { gas_left: gas, data: result, apply_state: _apply } => (gas, result.to_vec()),
@@ -65,8 +65,8 @@ fn test_finalize(res: Result<GasLeft, vm::Error>) -> Result<U256, vm::Error> {
 	}
 }
 
-fn wasm_interpreter(params: ActionParams) -> WasmInterpreter {
-	WasmInterpreter::new(params)
+fn wasm_interpreter(params: ActionParams) -> Box<WasmInterpreter> {
+	Box::new(WasmInterpreter::new(params))
 }
 
 /// Empty contract does almost nothing except producing 1 (one) local node debug log message
@@ -83,7 +83,7 @@ fn empty() {
 
 	let gas_left = {
 		let mut interpreter = wasm_interpreter(params);
-		test_finalize(interpreter.exec(&mut ext)).unwrap()
+		test_finalize(interpreter.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	assert_eq!(gas_left, U256::from(96_926));
@@ -112,7 +112,7 @@ fn logger() {
 
 	let gas_left = {
 		let mut interpreter = wasm_interpreter(params);
-		test_finalize(interpreter.exec(&mut ext)).unwrap()
+		test_finalize(interpreter.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	let address_val: H256 = address.into();
@@ -161,7 +161,7 @@ fn identity() {
 
 	let (gas_left, result) = {
 		let mut interpreter = wasm_interpreter(params);
-		let result = interpreter.exec(&mut ext).expect("Interpreter to execute without any errors");
+		let result = interpreter.exec(&mut ext).ok().unwrap().expect("Interpreter to execute without any errors");
 		match result {
 			GasLeft::Known(_) => { panic!("Identity contract should return payload"); },
 			GasLeft::NeedsReturn { gas_left: gas, data: result, apply_state: _apply } => (gas, result.to_vec()),
@@ -196,7 +196,7 @@ fn dispersion() {
 
 	let (gas_left, result) = {
 		let mut interpreter = wasm_interpreter(params);
-		let result = interpreter.exec(&mut ext).expect("Interpreter to execute without any errors");
+		let result = interpreter.exec(&mut ext).ok().unwrap().expect("Interpreter to execute without any errors");
 		match result {
 			GasLeft::Known(_) => { panic!("Dispersion routine should return payload"); },
 			GasLeft::NeedsReturn { gas_left: gas, data: result, apply_state: _apply } => (gas, result.to_vec()),
@@ -224,7 +224,7 @@ fn suicide_not() {
 
 	let (gas_left, result) = {
 		let mut interpreter = wasm_interpreter(params);
-		let result = interpreter.exec(&mut ext).expect("Interpreter to execute without any errors");
+		let result = interpreter.exec(&mut ext).ok().unwrap().expect("Interpreter to execute without any errors");
 		match result {
 			GasLeft::Known(_) => { panic!("Suicidal contract should return payload when had not actualy killed himself"); },
 			GasLeft::NeedsReturn { gas_left: gas, data: result, apply_state: _apply } => (gas, result.to_vec()),
@@ -257,7 +257,7 @@ fn suicide() {
 
 	let gas_left = {
 		let mut interpreter = wasm_interpreter(params);
-		let result = interpreter.exec(&mut ext).expect("Interpreter to execute without any errors");
+		let result = interpreter.exec(&mut ext).ok().unwrap().expect("Interpreter to execute without any errors");
 		match result {
 			GasLeft::Known(gas) => gas,
 			GasLeft::NeedsReturn { .. } => {
@@ -285,7 +285,7 @@ fn create() {
 
 	let gas_left = {
 		let mut interpreter = wasm_interpreter(params);
-		let result = interpreter.exec(&mut ext).expect("Interpreter to execute without any errors");
+		let result = interpreter.exec(&mut ext).ok().unwrap().expect("Interpreter to execute without any errors");
 		match result {
 			GasLeft::Known(_) => {
 				panic!("Create contract always return 40 bytes of the creation address, or in the case where it fails, return 40 bytes of zero.");
@@ -347,7 +347,7 @@ fn call_msg() {
 
 	let gas_left = {
 		let mut interpreter = wasm_interpreter(params);
-		let result = interpreter.exec(&mut ext).expect("Interpreter to execute without any errors");
+		let result = interpreter.exec(&mut ext).ok().unwrap().expect("Interpreter to execute without any errors");
 		match result {
 			GasLeft::Known(gas_left) => gas_left,
 			GasLeft::NeedsReturn { .. } => { panic!("Call test should not return payload"); },
@@ -395,7 +395,7 @@ fn call_msg_gasleft() {
 
 	let gas_left = {
 		let mut interpreter = wasm_interpreter(params);
-		let result = interpreter.exec(&mut ext).expect("Interpreter to execute without any errors");
+		let result = interpreter.exec(&mut ext).ok().unwrap().expect("Interpreter to execute without any errors");
 		match result {
 			GasLeft::Known(gas_left) => gas_left,
 			GasLeft::NeedsReturn { .. } => { panic!("Call test should not return payload"); },
@@ -438,7 +438,7 @@ fn call_code() {
 
 	let (gas_left, result) = {
 		let mut interpreter = wasm_interpreter(params);
-		let result = interpreter.exec(&mut ext).expect("Interpreter to execute without any errors");
+		let result = interpreter.exec(&mut ext).ok().unwrap().expect("Interpreter to execute without any errors");
 		match result {
 			GasLeft::Known(_) => { panic!("Call test should return payload"); },
 			GasLeft::NeedsReturn { gas_left: gas, data: result, apply_state: _apply } => (gas, result.to_vec()),
@@ -486,7 +486,7 @@ fn call_static() {
 
 	let (gas_left, result) = {
 		let mut interpreter = wasm_interpreter(params);
-		let result = interpreter.exec(&mut ext).expect("Interpreter to execute without any errors");
+		let result = interpreter.exec(&mut ext).ok().unwrap().expect("Interpreter to execute without any errors");
 		match result {
 			GasLeft::Known(_) => { panic!("Static call test should return payload"); },
 			GasLeft::NeedsReturn { gas_left: gas, data: result, apply_state: _apply } => (gas, result.to_vec()),
@@ -527,7 +527,7 @@ fn realloc() {
 
 	let (gas_left, result) = {
 		let mut interpreter = wasm_interpreter(params);
-		let result = interpreter.exec(&mut ext).expect("Interpreter to execute without any errors");
+		let result = interpreter.exec(&mut ext).ok().unwrap().expect("Interpreter to execute without any errors");
 		match result {
 				GasLeft::Known(_) => { panic!("Realloc should return payload"); },
 				GasLeft::NeedsReturn { gas_left: gas, data: result, apply_state: _apply } => (gas, result.to_vec()),
@@ -549,7 +549,7 @@ fn alloc() {
 
 	let (gas_left, result) = {
 		let mut interpreter = wasm_interpreter(params);
-		let result = interpreter.exec(&mut ext).expect("Interpreter to execute without any errors");
+		let result = interpreter.exec(&mut ext).ok().unwrap().expect("Interpreter to execute without any errors");
 		match result {
 				GasLeft::Known(_) => { panic!("alloc test should return payload"); },
 				GasLeft::NeedsReturn { gas_left: gas, data: result, apply_state: _apply } => (gas, result.to_vec()),
@@ -576,7 +576,7 @@ fn storage_read() {
 
 	let (gas_left, result) = {
 		let mut interpreter = wasm_interpreter(params);
-		let result = interpreter.exec(&mut ext).expect("Interpreter to execute without any errors");
+		let result = interpreter.exec(&mut ext).ok().unwrap().expect("Interpreter to execute without any errors");
 		match result {
 				GasLeft::Known(_) => { panic!("storage_read should return payload"); },
 				GasLeft::NeedsReturn { gas_left: gas, data: result, apply_state: _apply } => (gas, result.to_vec()),
@@ -602,7 +602,7 @@ fn keccak() {
 
 	let (gas_left, result) = {
 		let mut interpreter = wasm_interpreter(params);
-		let result = interpreter.exec(&mut ext).expect("Interpreter to execute without any errors");
+		let result = interpreter.exec(&mut ext).ok().unwrap().expect("Interpreter to execute without any errors");
 		match result {
 				GasLeft::Known(_) => { panic!("keccak should return payload"); },
 				GasLeft::NeedsReturn { gas_left: gas, data: result, apply_state: _apply } => (gas, result.to_vec()),
@@ -749,7 +749,7 @@ fn storage_metering() {
 
 	let gas_left = {
 		let mut interpreter = wasm_interpreter(params);
-		test_finalize(interpreter.exec(&mut ext)).unwrap()
+		test_finalize(interpreter.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	// 0 -> not 0
@@ -768,7 +768,7 @@ fn storage_metering() {
 
 	let gas_left = {
 		let mut interpreter = wasm_interpreter(params);
-		test_finalize(interpreter.exec(&mut ext)).unwrap()
+		test_finalize(interpreter.exec(&mut ext).ok().unwrap()).unwrap()
 	};
 
 	// not 0 -> not 0
@@ -875,8 +875,8 @@ fn gasleft() {
 	let mut ext = FakeExt::new().with_wasm();
 	ext.schedule.wasm.as_mut().unwrap().have_gasleft = true;
 
-	let mut interpreter = wasm_interpreter(params);
-	let result = interpreter.exec(&mut ext).expect("Interpreter to execute without any errors");
+	let interpreter = wasm_interpreter(params);
+	let result = interpreter.exec(&mut ext).ok().unwrap().expect("Interpreter to execute without any errors");
 	match result {
 		GasLeft::Known(_) => {},
 		GasLeft::NeedsReturn { gas_left, data, .. } => {
@@ -897,8 +897,8 @@ fn gasleft_fail() {
 	params.gas = U256::from(100_000);
 	params.code = Some(Arc::new(load_sample!("gasleft.wasm")));
 	let mut ext = FakeExt::new().with_wasm();
-	let mut interpreter = wasm_interpreter(params);
-	match interpreter.exec(&mut ext) {
+	let interpreter = wasm_interpreter(params);
+	match interpreter.exec(&mut ext).ok().unwrap() {
 		Err(_) => {},
 		Ok(_) => panic!("interpreter.exec should return Err if ext.schedule.wasm.have_gasleft = false")
 	}
@@ -919,7 +919,7 @@ fn embedded_keccak() {
 
 	let (gas_left, result) = {
 		let mut interpreter = wasm_interpreter(params);
-		let result = interpreter.exec(&mut ext).expect("Interpreter to execute without any errors");
+		let result = interpreter.exec(&mut ext).ok().unwrap().expect("Interpreter to execute without any errors");
 		match result {
 			GasLeft::Known(_) => { panic!("keccak should return payload"); },
 			GasLeft::NeedsReturn { gas_left: gas, data: result, apply_state: _apply } => (gas, result.to_vec()),
@@ -947,7 +947,7 @@ fn events() {
 
 	let (gas_left, result) = {
 		let mut interpreter = wasm_interpreter(params);
-		let result = interpreter.exec(&mut ext).expect("Interpreter to execute without any errors");
+		let result = interpreter.exec(&mut ext).ok().unwrap().expect("Interpreter to execute without any errors");
 		match result {
 			GasLeft::Known(_) => { panic!("events should return payload"); },
 			GasLeft::NeedsReturn { gas_left: gas, data: result, apply_state: _apply } => (gas, result.to_vec()),
@@ -986,8 +986,8 @@ fn recursive() {
 
 	let mut ext = FakeExt::new().with_wasm();
 
-	let mut interpreter = wasm_interpreter(params);
-	let result = interpreter.exec(&mut ext);
+	let interpreter = wasm_interpreter(params);
+	let result = interpreter.exec(&mut ext).ok().unwrap();
 
 	// We expect that stack overflow will occur and it should be generated by
 	// deterministic stack metering. Exceeding deterministic stack height limit

evmbin/src/display/json.rs

@@ -35,14 +35,28 @@ pub struct Informant {
 	instruction: u8,
 	gas_cost: U256,
 	gas_used: U256,
+	mem_written: Option<(usize, usize)>,
+	store_written: Option<(U256, U256)>,
 	stack: Vec<U256>,
 	memory: Vec<u8>,
 	storage: HashMap<H256, H256>,
 	traces: Vec<String>,
 	subtraces: Vec<String>,
+	subinfos: Vec<Informant>,
+	subdepth: usize,
 	unmatched: bool,
 }
 
+impl Informant {
+	fn with_informant_in_depth<F: Fn(&mut Informant)>(informant: &mut Informant, depth: usize, f: F) {
+		if depth == 0 {
+			f(informant);
+		} else {
+			Self::with_informant_in_depth(informant.subinfos.last_mut().expect("prepare/done_trace are not balanced"), depth - 1, f);
+		}
+	}
+}
+
 impl vm::Informant for Informant {
 	fn before_test(&mut self, name: &str, action: &str) {
 		println!("{}", json!({"action": action, "test": name}));
@@ -88,72 +102,92 @@ impl trace::VMTracer for Informant {
 	type Output = Vec<String>;
 
 	fn trace_next_instruction(&mut self, pc: usize, instruction: u8, _current_gas: U256) -> bool {
-		self.pc = pc;
-		self.instruction = instruction;
-		self.unmatched = true;
+		let subdepth = self.subdepth;
+		Self::with_informant_in_depth(self, subdepth, |informant: &mut Informant| {
+			informant.pc = pc;
+			informant.instruction = instruction;
+			informant.unmatched = true;
+		});
 		true
 	}
 
-	fn trace_prepare_execute(&mut self, pc: usize, instruction: u8, gas_cost: U256) {
-		self.pc = pc;
-		self.instruction = instruction;
-		self.gas_cost = gas_cost;
-	}
-
-	fn trace_executed(&mut self, gas_used: U256, stack_push: &[U256], mem_diff: Option<(usize, &[u8])>, store_diff: Option<(U256, U256)>) {
-		let info = ::evm::Instruction::from_u8(self.instruction).map(|i| i.info());
-
-		let trace = json!({
-			"pc": self.pc,
-			"op": self.instruction,
-			"opName": info.map(|i| i.name).unwrap_or(""),
-			"gas": format!("{:#x}", gas_used.saturating_add(self.gas_cost)),
-			"gasCost": format!("{:#x}", self.gas_cost),
-			"memory": format!("0x{}", self.memory.to_hex()),
-			"stack": self.stack,
-			"storage": self.storage,
-			"depth": self.depth,
+	fn trace_prepare_execute(&mut self, pc: usize, instruction: u8, gas_cost: U256, mem_written: Option<(usize, usize)>, store_written: Option<(U256, U256)>) {
+		let subdepth = self.subdepth;
+		Self::with_informant_in_depth(self, subdepth, |informant: &mut Informant| {
+			informant.pc = pc;
+			informant.instruction = instruction;
+			informant.gas_cost = gas_cost;
+			informant.mem_written = mem_written;
+			informant.store_written = store_written;
 		});
+	}
 
-		self.traces.push(trace.to_string());
+	fn trace_executed(&mut self, gas_used: U256, stack_push: &[U256], mem: &[u8]) {
+		let subdepth = self.subdepth;
+		Self::with_informant_in_depth(self, subdepth, |informant: &mut Informant| {
+			let mem_diff = informant.mem_written.clone().map(|(o, s)| (o, &(mem[o..o+s])));
+			let store_diff = informant.store_written.clone();
+			let info = ::evm::Instruction::from_u8(informant.instruction).map(|i| i.info());
 
-		self.unmatched = false;
-		self.gas_used = gas_used;
+			let trace = json!({
+				"pc": informant.pc,
+				"op": informant.instruction,
+				"opName": info.map(|i| i.name).unwrap_or(""),
+				"gas": format!("{:#x}", gas_used.saturating_add(informant.gas_cost)),
+				"gasCost": format!("{:#x}", informant.gas_cost),
+				"memory": format!("0x{}", informant.memory.to_hex()),
+				"stack": informant.stack,
+				"storage": informant.storage,
+				"depth": informant.depth,
+			});
+			informant.traces.push(trace.to_string());
 
-		let len = self.stack.len();
-		let info_args = info.map(|i| i.args).unwrap_or(0);
-		self.stack.truncate(if len > info_args { len - info_args } else { 0 });
-		self.stack.extend_from_slice(stack_push);
+			informant.unmatched = false;
+			informant.gas_used = gas_used;
 
-		// TODO [ToDr] Align memory?
-		if let Some((pos, data)) = mem_diff {
-			if self.memory.len() < (pos + data.len()) {
-				self.memory.resize(pos + data.len(), 0);
+			let len = informant.stack.len();
+			let info_args = info.map(|i| i.args).unwrap_or(0);
+			informant.stack.truncate(if len > info_args { len - info_args } else { 0 });
+			informant.stack.extend_from_slice(stack_push);
+
+			// TODO [ToDr] Align memory?
+			if let Some((pos, data)) = mem_diff {
+				if informant.memory.len() < (pos + data.len()) {
+					informant.memory.resize(pos + data.len(), 0);
+				}
+				informant.memory[pos..pos + data.len()].copy_from_slice(data);
 			}
-			self.memory[pos..pos + data.len()].copy_from_slice(data);
-		}
 
-		if let Some((pos, val)) = store_diff {
-			self.storage.insert(pos.into(), val.into());
-		}
+			if let Some((pos, val)) = store_diff {
+				informant.storage.insert(pos.into(), val.into());
+			}
 
-		if !self.subtraces.is_empty() {
-			self.traces.extend(mem::replace(&mut self.subtraces, vec![]));
-		}
+			if !informant.subtraces.is_empty() {
+				informant.traces.extend(mem::replace(&mut informant.subtraces, vec![]));
+			}
+		});
 	}
 
-	fn prepare_subtrace(&self, code: &[u8]) -> Self where Self: Sized {
-		let mut vm = Informant::default();
-		vm.depth = self.depth + 1;
-		vm.code = code.to_vec();
-		vm.gas_used = self.gas_used;
-		vm
+	fn prepare_subtrace(&mut self, code: &[u8]) {
+		let subdepth = self.subdepth;
+		Self::with_informant_in_depth(self, subdepth, |informant: &mut Informant| {
+			let mut vm = Informant::default();
+			vm.depth = informant.depth + 1;
+			vm.code = code.to_vec();
+			vm.gas_used = informant.gas_used;
+			informant.subinfos.push(vm);
+		});
+		self.subdepth += 1;
 	}
 
-	fn done_subtrace(&mut self, sub: Self) {
-		if let Some(subtraces) = sub.drain() {
-			self.subtraces.extend(subtraces);
-		}
+	fn done_subtrace(&mut self) {
+		self.subdepth -= 1;
+		let subdepth = self.subdepth;
+		Self::with_informant_in_depth(self, subdepth, |informant: &mut Informant| {
+			if let Some(subtraces) = informant.subinfos.pop().expect("prepare/done_subtrace are not balanced").drain() {
+				informant.subtraces.extend(subtraces);
+			}
+		});
 	}
 
 	fn drain(mut self) -> Option<Self::Output> {
@@ -161,7 +195,7 @@ impl trace::VMTracer for Informant {
 			// print last line with final state:
 			self.gas_cost = 0.into();
 			let gas_used = self.gas_used;
-			self.trace_executed(gas_used, &[], None, None);
+			self.trace_executed(gas_used, &[], &[]);
 		} else if !self.subtraces.is_empty() {
 			self.traces.extend(mem::replace(&mut self.subtraces, vec![]));
 		}

evmbin/src/display/simple.rs

@@ -49,7 +49,7 @@ impl vm::Informant for Informant {
 impl trace::VMTracer for Informant {
 	type Output = ();
 
-	fn prepare_subtrace(&self, _code: &[u8]) -> Self where Self: Sized { Default::default() }
-	fn done_subtrace(&mut self, _sub: Self) {}
+	fn prepare_subtrace(&mut self, _code: &[u8]) { Default::default() }
+	fn done_subtrace(&mut self) {}
 	fn drain(self) -> Option<()> { None }
 }

evmbin/src/display/std_json.rs

@@ -58,6 +58,8 @@ pub struct Informant<Trace = io::Stderr, Out = io::Stdout> {
 	depth: usize,
 	stack: Vec<U256>,
 	storage: HashMap<H256, H256>,
+	subinfos: Vec<Informant<Trace, Out>>,
+	subdepth: usize,
 	trace_sink: Trace,
 	out_sink: Out,
 }
@@ -76,9 +78,19 @@ impl<Trace: Writer, Out: Writer> Informant<Trace, Out> {
 			depth: Default::default(),
 			stack: Default::default(),
 			storage: Default::default(),
+			subinfos: Default::default(),
+			subdepth: 0,
 			trace_sink, out_sink
 		}
 	}
+
+	fn with_informant_in_depth<F: Fn(&mut Informant<Trace, Out>)>(informant: &mut Informant<Trace, Out>, depth: usize, f: F) {
+		if depth == 0 {
+			f(informant);
+		} else {
+			Self::with_informant_in_depth(informant.subinfos.last_mut().expect("prepare/done_trace are not balanced"), depth - 1, f);
+		}
+	}
 }
 
 impl<Trace: Writer, Out: Writer> vm::Informant for Informant<Trace, Out> {
@@ -128,47 +140,64 @@ impl<Trace: Writer, Out: Writer> trace::VMTracer for Informant<Trace, Out> {
 	type Output = ();
 
 	fn trace_next_instruction(&mut self, pc: usize, instruction: u8, current_gas: U256) -> bool {
-		let info = ::evm::Instruction::from_u8(instruction).map(|i| i.info());
-		self.instruction = instruction;
-		let trace_data = json!({
-			"pc": pc,
-			"op": instruction,
-			"opName": info.map(|i| i.name).unwrap_or(""),
-			"gas": format!("{:#x}", current_gas),
-			"stack": self.stack,
-			"storage": self.storage,
-			"depth": self.depth,
+		let subdepth = self.subdepth;
+		Self::with_informant_in_depth(self, subdepth, |informant: &mut Informant<Trace, Out>| {
+			let info = ::evm::Instruction::from_u8(instruction).map(|i| i.info());
+			informant.instruction = instruction;
+			let trace_data = json!({
+				"pc": pc,
+				"op": instruction,
+				"opName": info.map(|i| i.name).unwrap_or(""),
+				"gas": format!("{:#x}", current_gas),
+				"stack": informant.stack,
+				"storage": informant.storage,
+				"depth": informant.depth,
+			});
+
+			writeln!(&mut informant.trace_sink, "{}", trace_data).expect("The sink must be writeable.");
 		});
-
-		writeln!(&mut self.trace_sink, "{}", trace_data).expect("The sink must be writeable.");
-
 		true
 	}
 
-	fn trace_prepare_execute(&mut self, _pc: usize, _instruction: u8, _gas_cost: U256) {
+	fn trace_prepare_execute(&mut self, _pc: usize, _instruction: u8, _gas_cost: U256, _mem_written: Option<(usize, usize)>, store_written: Option<(U256, U256)>) {
+		let subdepth = self.subdepth;
+		Self::with_informant_in_depth(self, subdepth, |informant: &mut Informant<Trace, Out>| {
+			if let Some((pos, val)) = store_written {
+				informant.storage.insert(pos.into(), val.into());
+			}
+		});
 	}
 
-	fn trace_executed(&mut self, _gas_used: U256, stack_push: &[U256], _mem_diff: Option<(usize, &[u8])>, store_diff: Option<(U256, U256)>) {
-		let info = ::evm::Instruction::from_u8(self.instruction).map(|i| i.info());
+	fn trace_executed(&mut self, _gas_used: U256, stack_push: &[U256], _mem: &[u8]) {
+		let subdepth = self.subdepth;
+		Self::with_informant_in_depth(self, subdepth, |informant: &mut Informant<Trace, Out>| {
+			let info = ::evm::Instruction::from_u8(informant.instruction).map(|i| i.info());
 
-		let len = self.stack.len();
-		let info_args = info.map(|i| i.args).unwrap_or(0);
-		self.stack.truncate(if len > info_args { len - info_args } else { 0 });
-		self.stack.extend_from_slice(stack_push);
-
-		if let Some((pos, val)) = store_diff {
-			self.storage.insert(pos.into(), val.into());
-		}
+			let len = informant.stack.len();
+			let info_args = info.map(|i| i.args).unwrap_or(0);
+			informant.stack.truncate(if len > info_args { len - info_args } else { 0 });
+			informant.stack.extend_from_slice(stack_push);
+		});
 	}
 
-	fn prepare_subtrace(&self, code: &[u8]) -> Self where Self: Sized {
-		let mut vm = Informant::new(self.trace_sink.clone(), self.out_sink.clone());
-		vm.depth = self.depth + 1;
-		vm.code = code.to_vec();
-		vm
+	fn prepare_subtrace(&mut self, code: &[u8]) {
+		let subdepth = self.subdepth;
+		Self::with_informant_in_depth(self, subdepth, |informant: &mut Informant<Trace, Out>| {
+			let mut vm = Informant::new(informant.trace_sink.clone(), informant.out_sink.clone());
+			vm.depth = informant.depth + 1;
+			vm.code = code.to_vec();
+			informant.subinfos.push(vm);
+		});
+		self.subdepth += 1;
 	}
 
-	fn done_subtrace(&mut self, _sub: Self) {}
+	fn done_subtrace(&mut self) {
+		self.subdepth -= 1;
+		let subdepth = self.subdepth;
+		Self::with_informant_in_depth(self, subdepth, |informant: &mut Informant<Trace, Out>| {
+			informant.subinfos.pop();
+		});
+	}
 
 	fn drain(self) -> Option<Self::Output> { None }
 }