#222 - Support Empty Account

gasometer/src/lib.rs

@@ -172,6 +172,14 @@ impl<'config> Gasometer<'config> {
 		Ok(())
 	}
 
+	#[inline]
+	/// Check gas limit before `CREATE` code deposit. (See EIP-2)
+	pub fn can_deposit(&self, len: usize) -> bool {
+		let cost = len as u64 * consts::G_CODEDEPOSIT;
+		let all_gas_cost = self.total_used_gas() + cost;
+		self.gas_limit >= all_gas_cost
+	}
+
 	#[inline]
 	/// Record `CREATE` code deposit.
 	pub fn record_deposit(&mut self, len: usize) -> Result<(), ExitError> {

runtime/src/lib.rs

@@ -252,6 +252,8 @@ pub struct Config {
 	pub call_l64_after_gas: bool,
 	/// Whether empty account is considered exists.
 	pub empty_considered_exists: bool,
+	/// Create empty contract if there's no gas for paying code deposit.
+	pub can_create_empty_contract: bool,
 	/// Whether create transactions and create opcode increases nonce by one.
 	pub create_increase_nonce: bool,
 	/// Stack limit.
@@ -278,6 +280,8 @@ pub struct Config {
 	pub has_bitwise_shifting: bool,
 	/// Has chain ID.
 	pub has_chain_id: bool,
+	/// Has static_call. See [EIP-214](https://github.com/ethereum/EIPs/blob/master/EIPS/eip-214.md)
+	pub has_static_call: bool,
 	/// Has self balance.
 	pub has_self_balance: bool,
 	/// Has ext code hash.
@@ -323,6 +327,7 @@ impl Config {
 			warm_coinbase_address: false,
 			err_on_call_with_more_gas: true,
 			empty_considered_exists: true,
+			can_create_empty_contract: true,
 			create_increase_nonce: false,
 			call_l64_after_gas: false,
 			stack_limit: 1024,
@@ -337,6 +342,7 @@ impl Config {
 			has_return_data: false,
 			has_bitwise_shifting: false,
 			has_chain_id: false,
+			has_static_call: false,
 			has_self_balance: false,
 			has_ext_code_hash: false,
 			has_base_fee: false,
@@ -345,6 +351,101 @@ impl Config {
 		}
 	}
 
+	/// Homestead hard fork configuration.
+	/// mainnet block number: 1,150,000
+	pub const fn homestead() -> Config {
+		let mut config = Self::frontier();
+		// makes edits to contract creation process
+		// see [EIP-2](https://eips.ethereum.org/EIPS/eip-2)
+		config.gas_transaction_create = 53_000;
+		config.can_create_empty_contract = false;
+		config.empty_considered_exists = true;
+
+		// Enable delegate call opcode
+		// see [EIP-7](https://eips.ethereum.org/EIPS/eip-7)
+		config.has_delegate_call = true;
+		config
+	}
+
+	/// Tangerine whistle hard fork configuration.
+	pub const fn tangerine_whistle() -> Config {
+		let mut config = Self::homestead();
+		// Gas cost changes for IO-heavy operations
+		// see [EIP-150](https://eips.ethereum.org/EIPS/eip-150)
+		config.gas_ext_code = 700;
+		config.gas_balance = 400;
+		config.gas_sload = 200;
+		config.gas_call = 700;
+		config.gas_suicide = 5_000;
+		config.gas_suicide_new_account = 25_000;
+		config.err_on_call_with_more_gas = false;
+		config.call_l64_after_gas = true;
+		config
+	}
+
+	/// Spurious Dragon hard fork configuration.
+	pub const fn spurious_dragon() -> Config {
+		let mut config = Self::tangerine_whistle();
+		// EXP cost increase
+		// see [EIP-160](https://eips.ethereum.org/EIPS/eip-160)
+		config.gas_expbyte = 50;
+
+		// State trie clearing
+		// - An account is considered empty when it has no code and zero nonce and zero balance. It should be noted
+		// that very few state changes can ultimately result in accounts that are empty following the execution of the transaction:
+		//    - an empty account has zero value transferred to it through CALL;
+		//    - an empty account has zero value transferred to it through SUICIDE;
+		//    - an empty account has zero value transferred to it through a message-call transaction;
+		//    - an empty account has zero value transferred to it through a zero-gas-price fees transfer.
+		//    - empty account deletions are reverted when the state is reverted.
+		// - An account is considered dead when either it is non-existent or it is empty.
+		// see [EIP-161](https://eips.ethereum.org/EIPS/eip-161)
+		config.create_increase_nonce = true;
+		config.empty_considered_exists = false;
+
+		// Contract code size limit
+		// see [EIP-170](https://eips.ethereum.org/EIPS/eip-170)
+		config.create_contract_limit = Some(0x6000);
+		config
+	}
+
+	/// Byzantium hard fork configuration.
+	pub const fn byzantium() -> Config {
+		let mut config = Self::spurious_dragon();
+
+		// adds REVERT opcode
+		// see [EIP-140](https://eips.ethereum.org/EIPS/eip-140)
+		config.has_revert = true;
+
+		// adds support for variable length return values
+		// see [EIP-211](https://eips.ethereum.org/EIPS/eip-211)
+		config.has_return_data = true;
+
+		// adds STATICCALL opcode, allowing non-state-changing calls to other contracts.
+		// see [EIP-214](https://eips.ethereum.org/EIPS/eip-214)
+		config.has_static_call = true;
+		config
+	}
+
+	/// Constantinople hard fork configuration.
+	pub const fn constantinople() -> Config {
+		let mut config = Self::byzantium();
+
+		// adds Bitwise shifting instructions
+		// see [EIP-145](https://eips.ethereum.org/EIPS/eip-145)
+		config.has_bitwise_shifting = true;
+
+		// allows you to interact with addresses that have yet to be created.
+		// see [EIP-1014](https://eips.ethereum.org/EIPS/eip-1014)
+		config.has_create2 = true;
+
+		// adds EXTCODEHASH opcode
+		// see [EIP-1052](https://eips.ethereum.org/EIPS/eip-1052)
+		config.has_ext_code_hash = true;
+		config.gas_ext_code_hash = 400;
+		config
+	}
+
 	/// Istanbul hard fork configuration.
 	pub const fn istanbul() -> Config {
 		Config {
@@ -377,6 +478,7 @@ impl Config {
 			warm_coinbase_address: false,
 			err_on_call_with_more_gas: false,
 			empty_considered_exists: false,
+			can_create_empty_contract: false,
 			create_increase_nonce: true,
 			call_l64_after_gas: true,
 			stack_limit: 1024,
@@ -391,6 +493,7 @@ impl Config {
 			has_return_data: true,
 			has_bitwise_shifting: true,
 			has_chain_id: true,
+			has_static_call: true,
 			has_self_balance: true,
 			has_ext_code_hash: true,
 			has_base_fee: false,
@@ -474,6 +577,7 @@ impl Config {
 			warm_coinbase_address,
 			err_on_call_with_more_gas: false,
 			empty_considered_exists: false,
+			can_create_empty_contract: false,
 			create_increase_nonce: true,
 			call_l64_after_gas: true,
 			stack_limit: 1024,
@@ -488,6 +592,7 @@ impl Config {
 			has_return_data: true,
 			has_bitwise_shifting: true,
 			has_chain_id: true,
+			has_static_call: true,
 			has_self_balance: true,
 			has_ext_code_hash: true,
 			has_base_fee,

src/executor/stack/executor.rs

@@ -1002,20 +1002,35 @@ impl<'config, 'precompiles, S: StackState<'config>, P: PrecompileSet>
 					}
 				}
 
-				match self
-					.state
-					.metadata_mut()
-					.gasometer
-					.record_deposit(out.len())
+				// Before EIP-2 is possible to create empty contract
+				let bytecode = if self.config.can_create_empty_contract
+					&& !self.state.metadata().gasometer.can_deposit(out.len())
 				{
-					Ok(()) => {
+					Ok(None)
+				} else {
+					self.state
+						.metadata_mut()
+						.gasometer
+						.record_deposit(out.len())
+						.map(|_| Some(out))
+				};
+
+				match bytecode {
+					Ok(Some(bytecode)) => {
 						let exit_result = self.exit_substate(StackExitKind::Succeeded);
 						if let Err(e) = self.record_external_operation(
-							crate::ExternalOperation::Write(U256::from(out.len())),
+							crate::ExternalOperation::Write(U256::from(bytecode.len())),
 						) {
 							return (e.into(), None, Vec::new());
 						}
-						self.state.set_code(address, out);
+						self.state.set_code(address, bytecode);
+						if let Err(e) = exit_result {
+							return (e.into(), None, Vec::new());
+						}
+						(ExitReason::Succeed(s), Some(address), Vec::new())
+					}
+					Ok(None) => {
+						let exit_result = self.exit_substate(StackExitKind::Succeeded);
 						if let Err(e) = exit_result {
 							return (e.into(), None, Vec::new());
 						}
@@ -1320,6 +1335,7 @@ impl<'config, 'precompiles, S: StackState<'config>, P: PrecompileSet> Handler
 		stack: &Stack,
 	) -> Result<(), ExitError> {
 		// log::trace!(target: "evm", "Running opcode: {:?}, Pre gas-left: {:?}", opcode, gasometer.gas());
+		// log::trace!(target: "evm", "Running opcode: {:?}, Pre gas-left: {:?}", opcode, self.state.metadata().gasometer.gas());
 
 		if let Some(cost) = gasometer::static_opcode_cost(opcode) {
 			self.state.metadata_mut().gasometer.record_cost(cost)?;