Handler/Opcode: extend interface to introduce transient storage (EIP-…

…1153)

https://eips.ethereum.org/EIPS/eip-1153

core/src/opcode.rs

@@ -227,6 +227,10 @@ impl Opcode {
 	pub const SLOAD: Opcode = Opcode(0x54);
 	/// `SSTORE`
 	pub const SSTORE: Opcode = Opcode(0x55);
+	/// `TLOAD`
+	pub const TLOAD: Opcode = Opcode(0x5c);
+	/// `TSTORE`
+	pub const TSTORE: Opcode = Opcode(0x5d);
 	/// `GAS`
 	pub const GAS: Opcode = Opcode(0x5a);
 	/// `LOGn`

runtime/src/eval/mod.rs

@@ -44,6 +44,8 @@ pub fn eval<H: Handler>(state: &mut Runtime, opcode: Opcode, handler: &mut H) ->
 		Opcode::GASLIMIT => system::gaslimit(state, handler),
 		Opcode::SLOAD => system::sload(state, handler),
 		Opcode::SSTORE => system::sstore(state, handler),
+		Opcode::TLOAD => system::tload(state, handler),
+		Opcode::TSTORE => system::tstore(state, handler),
 		Opcode::GAS => system::gas(state, handler),
 		Opcode::LOG0 => system::log(state, 0, handler),
 		Opcode::LOG1 => system::log(state, 1, handler),

runtime/src/eval/system.rs

@@ -236,6 +236,27 @@ pub fn sstore<H: Handler>(runtime: &mut Runtime, handler: &mut H) -> Control<H>
 	}
 }
 
+pub fn tload<H: Handler>(runtime: &mut Runtime, handler: &H) -> Control<H> {
+	pop!(runtime, index);
+	let value = handler.transient_storage(index);
+	push!(runtime, value);
+
+	event!(TLoad { index, value });
+
+	Control::Continue
+}
+
+pub fn tstore<H: Handler>(runtime: &mut Runtime, handler: &mut H) -> Control<H> {
+	pop!(runtime, index, value);
+
+	event!(TStore { index, value });
+
+	match handler.set_transient_storage(index, value) {
+		Ok(()) => Control::Continue,
+		Err(e) => Control::Exit(e.into()),
+	}
+}
+
 pub fn gas<H: Handler>(runtime: &mut Runtime, handler: &H) -> Control<H> {
 	push_u256!(runtime, handler.gas_left());
 

runtime/src/handler.rs

@@ -35,6 +35,8 @@ pub trait Handler {
 	fn code(&self, address: H160) -> Vec<u8>;
 	/// Get storage value of address at index.
 	fn storage(&self, address: H160, index: H256) -> H256;
+	/// Get transient storage value at index.
+	fn transient_storage(&self, index: H256) -> H256;
 	/// Get original storage value of address at index.
 	fn original_storage(&self, address: H160, index: H256) -> H256;
 
@@ -79,6 +81,8 @@ pub trait Handler {
 
 	/// Set storage value of address at index.
 	fn set_storage(&mut self, address: H160, index: H256, value: H256) -> Result<(), ExitError>;
+	/// Set transient storage value at index.
+	fn set_transient_storage(&mut self, index: H256, value: H256) -> Result<(), ExitError>;
 	/// Create a log owned by address with given topics and data.
 	fn log(&mut self, address: H160, topics: Vec<H256>, data: Vec<u8>) -> Result<(), ExitError>;
 	/// Mark an address to be deleted, with funds transferred to target.

runtime/src/tracing.rs

@@ -32,6 +32,14 @@ pub enum Event<'a> {
 		index: H256,
 		value: H256,
 	},
+	TLoad {
+		index: H256,
+		value: H256,
+	},
+	TStore {
+		index: H256,
+		value: H256,
+	},
 }
 
 // Expose `listener::with` to the crate only.

src/backend/memory.rs

@@ -63,15 +63,21 @@ pub struct MemoryAccount {
 pub struct MemoryBackend<'vicinity> {
 	vicinity: &'vicinity MemoryVicinity,
 	state: BTreeMap<H160, MemoryAccount>,
+	transient_state: BTreeMap<H256, H256>,
 	logs: Vec<Log>,
 }
 
 impl<'vicinity> MemoryBackend<'vicinity> {
 	/// Create a new memory backend.
-	pub fn new(vicinity: &'vicinity MemoryVicinity, state: BTreeMap<H160, MemoryAccount>) -> Self {
+	pub fn new(
+		vicinity: &'vicinity MemoryVicinity,
+		state: BTreeMap<H160, MemoryAccount>,
+		transient_state: BTreeMap<H256, H256>,
+	) -> Self {
 		Self {
 			vicinity,
 			state,
+			transient_state,
 			logs: Vec::new(),
 		}
 	}
@@ -163,6 +169,13 @@ impl<'vicinity> Backend for MemoryBackend<'vicinity> {
 			.unwrap_or_default()
 	}
 
+	fn transient_storage(&self, index: H256) -> H256 {
+		self.transient_state
+			.get(&index)
+			.cloned()
+			.unwrap_or_default()
+	}
+
 	fn original_storage(&self, address: H160, index: H256) -> Option<H256> {
 		Some(self.storage(address, index))
 	}

src/backend/mod.rs

@@ -85,6 +85,8 @@ pub trait Backend {
 	fn code(&self, address: H160) -> Vec<u8>;
 	/// Get storage value of address at index.
 	fn storage(&self, address: H160, index: H256) -> H256;
+	/// Get storage value at index.
+	fn transient_storage(&self, index: H256) -> H256;
 	/// Get original storage value of address at index, if available.
 	fn original_storage(&self, address: H160, index: H256) -> Option<H256>;
 }

src/executor/stack/executor.rs

@@ -206,6 +206,7 @@ pub trait StackState<'config>: Backend {
 
 	fn inc_nonce(&mut self, address: H160) -> Result<(), ExitError>;
 	fn set_storage(&mut self, address: H160, key: H256, value: H256);
+	fn set_transient_storage(&mut self, key: H256, value: H256);
 	fn reset_storage(&mut self, address: H160);
 	fn log(&mut self, address: H160, topics: Vec<H256>, data: Vec<u8>);
 	fn set_deleted(&mut self, address: H160);
@@ -1047,6 +1048,10 @@ impl<'config, 'precompiles, S: StackState<'config>, P: PrecompileSet> Handler
 		self.state.storage(address, index)
 	}
 
+	fn transient_storage(&self, index: H256) -> H256 {
+		self.state.transient_storage(index)
+	}
+
 	fn original_storage(&self, address: H160, index: H256) -> H256 {
 		self.state
 			.original_storage(address, index)
@@ -1137,6 +1142,11 @@ impl<'config, 'precompiles, S: StackState<'config>, P: PrecompileSet> Handler
 		Ok(())
 	}
 
+	fn set_transient_storage(&mut self, index: H256, value: H256) -> Result<(), ExitError> {
+		self.state.set_transient_storage(index, value);
+		Ok(())
+	}
+
 	fn log(&mut self, address: H160, topics: Vec<H256>, data: Vec<u8>) -> Result<(), ExitError> {
 		self.state.log(address, topics, data);
 		Ok(())

src/executor/stack/memory.rs

@@ -23,6 +23,7 @@ pub struct MemoryStackSubstate<'config> {
 	logs: Vec<Log>,
 	accounts: BTreeMap<H160, MemoryStackAccount>,
 	storages: BTreeMap<(H160, H256), H256>,
+	transient_storages: BTreeMap<H256, H256>,
 	deletes: BTreeSet<H160>,
 }
 
@@ -34,6 +35,7 @@ impl<'config> MemoryStackSubstate<'config> {
 			logs: Vec::new(),
 			accounts: BTreeMap::new(),
 			storages: BTreeMap::new(),
+			transient_storages: BTreeMap::new(),
 			deletes: BTreeSet::new(),
 		}
 	}
@@ -119,6 +121,7 @@ impl<'config> MemoryStackSubstate<'config> {
 			logs: Vec::new(),
 			accounts: BTreeMap::new(),
 			storages: BTreeMap::new(),
+			transient_storages: BTreeMap::new(),
 			deletes: BTreeSet::new(),
 		};
 		mem::swap(&mut entering, self);
@@ -231,6 +234,17 @@ impl<'config> MemoryStackSubstate<'config> {
 
 		None
 	}
+	pub fn known_transient_storage(&self, key: H256) -> Option<H256> {
+		if let Some(value) = self.transient_storages.get(&key) {
+			return Some(*value);
+		}
+
+		if let Some(parent) = self.parent.as_ref() {
+			return parent.known_transient_storage(key);
+		}
+
+		None
+	}
 
 	pub fn known_original_storage(&self, address: H160) -> Option<H256> {
 		if let Some(account) = self.accounts.get(&address) {
@@ -314,6 +328,10 @@ impl<'config> MemoryStackSubstate<'config> {
 		self.storages.insert((address, key), value);
 	}
 
+	pub fn set_transient_storage(&mut self, key: H256, value: H256) {
+		self.transient_storages.insert(key, value);
+	}
+
 	pub fn reset_storage<B: Backend>(&mut self, address: H160, backend: &B) {
 		let mut removing = Vec::new();
 
@@ -465,6 +483,12 @@ impl<'backend, 'config, B: Backend> Backend for MemoryStackState<'backend, 'conf
 			.unwrap_or_else(|| self.backend.storage(address, key))
 	}
 
+	fn transient_storage(&self, key: H256) -> H256 {
+		self.substate
+			.known_transient_storage(key)
+			.unwrap_or_else(|| self.backend.transient_storage(key))
+	}
+
 	fn original_storage(&self, address: H160, key: H256) -> Option<H256> {
 		if let Some(value) = self.substate.known_original_storage(address) {
 			return Some(value);
@@ -529,6 +553,10 @@ impl<'backend, 'config, B: Backend> StackState<'config> for MemoryStackState<'ba
 		self.substate.set_storage(address, key, value)
 	}
 
+	fn set_transient_storage(&mut self, key: H256, value: H256) {
+		self.substate.set_transient_storage(key, value)
+	}
+
 	fn reset_storage(&mut self, address: H160) {
 		self.substate.reset_storage(address, self.backend);
 	}