contracts: Run start function

substrate/frame/contracts/fixtures/run_out_of_gas_start_fn.wat

@@ -0,0 +1,10 @@
+(module
+	(import "env" "memory" (memory 1 1))
+	(start $start)
+	(func $start
+		(loop $inf (br $inf)) ;; just run out of gas
+		(unreachable)
+	)
+	(func (export "call"))
+	(func (export "deploy"))
+)

substrate/frame/contracts/src/benchmarking/sandbox.rs

@@ -58,7 +58,13 @@ impl<T: Config> From<&WasmModule<T>> for Sandbox {
 			.add_fuel(u64::MAX)
 			.expect("We've set up engine to fuel consuming mode; qed");
 
-		let entry_point = instance.get_export(&store, "call").unwrap().into_func().unwrap();
+		let entry_point = instance
+			.start(&mut store)
+			.unwrap()
+			.get_export(&store, "call")
+			.unwrap()
+			.into_func()
+			.unwrap();
 		Self { entry_point, store }
 	}
 }

substrate/frame/contracts/src/exec.rs

@@ -21,7 +21,7 @@ use crate::{
 	storage::{self, meter::Diff, WriteOutcome},
 	BalanceOf, CodeHash, CodeInfo, CodeInfoOf, Config, ContractInfo, ContractInfoOf,
 	DebugBufferVec, Determinism, Error, Event, Nonce, Origin, Pallet as Contracts, Schedule,
-	WasmBlob, LOG_TARGET,
+	LOG_TARGET,
 };
 use frame_support::{
 	crypto::ecdsa::ECDSAExt,
@@ -318,6 +318,22 @@ pub trait Ext: sealing::Sealed {
 	/// Returns a nonce that is incremented for every instantiated contract.
 	fn nonce(&mut self) -> u64;
 
+	/// Increment the reference count of a of a stored code by one.
+	///
+	/// # Errors
+	///
+	/// [`Error::CodeNotFound`] is returned if no stored code found having the specified
+	/// `code_hash`.
+	fn increment_refcount(code_hash: CodeHash<Self::T>) -> Result<(), DispatchError>;
+
+	/// Decrement the reference count of a stored code by one.
+	///
+	/// # Note
+	///
+	/// A contract whose reference count dropped to zero isn't automatically removed. A
+	/// `remove_code` transaction must be submitted by the original uploader to do so.
+	fn decrement_refcount(code_hash: CodeHash<Self::T>);
+
 	/// Adds a delegate dependency to [`ContractInfo`]'s `delegate_dependencies` field.
 	///
 	/// This ensures that the delegated contract is not removed while it is still in use. It
@@ -381,22 +397,6 @@ pub trait Executable<T: Config>: Sized {
 		gas_meter: &mut GasMeter<T>,
 	) -> Result<Self, DispatchError>;
 
-	/// Increment the reference count of a of a stored code by one.
-	///
-	/// # Errors
-	///
-	/// [`Error::CodeNotFound`] is returned if no stored code found having the specified
-	/// `code_hash`.
-	fn increment_refcount(code_hash: CodeHash<T>) -> Result<(), DispatchError>;
-
-	/// Decrement the reference count of a stored code by one.
-	///
-	/// # Note
-	///
-	/// A contract whose reference count dropped to zero isn't automatically removed. A
-	/// `remove_code` transaction must be submitted by the original uploader to do so.
-	fn decrement_refcount(code_hash: CodeHash<T>);
-
 	/// Execute the specified exported function and return the result.
 	///
 	/// When the specified function is `Constructor` the executable is stored and its
@@ -1285,10 +1285,10 @@ where
 
 		info.queue_trie_for_deletion();
 		ContractInfoOf::<T>::remove(&frame.account_id);
-		E::decrement_refcount(info.code_hash);
+		Self::decrement_refcount(info.code_hash);
 
 		for (code_hash, deposit) in info.delegate_dependencies() {
-			E::decrement_refcount(*code_hash);
+			Self::decrement_refcount(*code_hash);
 			frame
 				.nested_storage
 				.charge_deposit(frame.account_id.clone(), StorageDeposit::Refund(*deposit));
@@ -1491,8 +1491,8 @@ where
 
 		frame.nested_storage.charge_deposit(frame.account_id.clone(), deposit);
 
-		E::increment_refcount(hash)?;
-		E::decrement_refcount(prev_hash);
+		Self::increment_refcount(hash)?;
+		Self::decrement_refcount(prev_hash);
 		Contracts::<Self::T>::deposit_event(
 			vec![T::Hashing::hash_of(&frame.account_id), hash, prev_hash],
 			Event::ContractCodeUpdated {
@@ -1525,6 +1525,25 @@ where
 		}
 	}
 
+	fn increment_refcount(code_hash: CodeHash<Self::T>) -> Result<(), DispatchError> {
+		<CodeInfoOf<Self::T>>::mutate(code_hash, |existing| -> Result<(), DispatchError> {
+			if let Some(info) = existing {
+				*info.refcount_mut() = info.refcount().saturating_add(1);
+				Ok(())
+			} else {
+				Err(Error::<T>::CodeNotFound.into())
+			}
+		})
+	}
+
+	fn decrement_refcount(code_hash: CodeHash<T>) {
+		<CodeInfoOf<T>>::mutate(code_hash, |existing| {
+			if let Some(info) = existing {
+				*info.refcount_mut() = info.refcount().saturating_sub(1);
+			}
+		});
+	}
+
 	fn add_delegate_dependency(
 		&mut self,
 		code_hash: CodeHash<Self::T>,
@@ -1537,7 +1556,7 @@ where
 		let deposit = T::CodeHashLockupDepositPercent::get().mul_ceil(code_info.deposit());
 
 		info.add_delegate_dependency(code_hash, deposit)?;
-		<WasmBlob<T>>::increment_refcount(code_hash)?;
+		Self::increment_refcount(code_hash)?;
 		frame
 			.nested_storage
 			.charge_deposit(frame.account_id.clone(), StorageDeposit::Charge(deposit));
@@ -1552,8 +1571,7 @@ where
 		let info = frame.contract_info.get(&frame.account_id);
 
 		let deposit = info.remove_delegate_dependency(code_hash)?;
-		<WasmBlob<T>>::decrement_refcount(*code_hash);
-
+		Self::decrement_refcount(*code_hash);
 		frame
 			.nested_storage
 			.charge_deposit(frame.account_id.clone(), StorageDeposit::Refund(deposit));
@@ -1600,11 +1618,7 @@ mod tests {
 	use pallet_contracts_primitives::ReturnFlags;
 	use pretty_assertions::assert_eq;
 	use sp_runtime::{traits::Hash, DispatchError};
-	use std::{
-		cell::RefCell,
-		collections::hash_map::{Entry, HashMap},
-		rc::Rc,
-	};
+	use std::{cell::RefCell, collections::hash_map::HashMap, rc::Rc};
 
 	type System = frame_system::Pallet<Test>;
 
@@ -1635,7 +1649,6 @@ mod tests {
 		func_type: ExportedFunction,
 		code_hash: CodeHash<Test>,
 		code_info: CodeInfo<Test>,
-		refcount: u64,
 	}
 
 	#[derive(Default, Clone)]
@@ -1664,37 +1677,11 @@ mod tests {
 						func_type,
 						code_hash: hash,
 						code_info: CodeInfo::<Test>::new(ALICE),
-						refcount: 1,
 					},
 				);
 				hash
 			})
 		}
-
-		fn increment_refcount(code_hash: CodeHash<Test>) -> Result<(), DispatchError> {
-			Loader::mutate(|loader| {
-				match loader.map.entry(code_hash) {
-					Entry::Vacant(_) => Err(<Error<Test>>::CodeNotFound)?,
-					Entry::Occupied(mut entry) => entry.get_mut().refcount += 1,
-				}
-				Ok(())
-			})
-		}
-
-		fn decrement_refcount(code_hash: CodeHash<Test>) {
-			use std::collections::hash_map::Entry::Occupied;
-			Loader::mutate(|loader| {
-				let mut entry = match loader.map.entry(code_hash) {
-					Occupied(e) => e,
-					_ => panic!("code_hash does not exist"),
-				};
-				let refcount = &mut entry.get_mut().refcount;
-				*refcount -= 1;
-				if *refcount == 0 {
-					entry.remove();
-				}
-			});
-		}
 	}
 
 	impl Executable<Test> for MockExecutable {
@@ -1707,22 +1694,14 @@ mod tests {
 			})
 		}
 
-		fn increment_refcount(code_hash: CodeHash<Test>) -> Result<(), DispatchError> {
-			MockLoader::increment_refcount(code_hash)
-		}
-
-		fn decrement_refcount(code_hash: CodeHash<Test>) {
-			MockLoader::decrement_refcount(code_hash);
-		}
-
 		fn execute<E: Ext<T = Test>>(
 			self,
 			ext: &mut E,
 			function: &ExportedFunction,
 			input_data: Vec<u8>,
 		) -> ExecResult {
 			if let &Constructor = function {
-				Self::increment_refcount(self.code_hash).unwrap();
+				E::increment_refcount(self.code_hash).unwrap();
 			}
 			// # Safety
 			//
@@ -1733,7 +1712,7 @@ mod tests {
 			// The transmute is necessary because `execute` has to be generic over all
 			// `E: Ext`. However, `MockExecutable` can't be generic over `E` as it would
 			// constitute a cycle.
-			let ext = unsafe { std::mem::transmute(ext) };
+			let ext = unsafe { mem::transmute(ext) };
 			if function == &self.func_type {
 				(self.func)(MockCtx { ext, input_data }, &self)
 			} else {

substrate/frame/contracts/src/lib.rs

@@ -103,7 +103,9 @@ pub mod weights;
 #[cfg(test)]
 mod tests;
 use crate::{
-	exec::{AccountIdOf, ErrorOrigin, ExecError, Executable, Key, MomentOf, Stack as ExecStack},
+	exec::{
+		AccountIdOf, ErrorOrigin, ExecError, Executable, Ext, Key, MomentOf, Stack as ExecStack,
+	},
 	gas::GasMeter,
 	storage::{meter::Meter as StorageMeter, ContractInfo, DeletionQueueManager},
 	wasm::{CodeInfo, WasmBlob},
@@ -658,8 +660,8 @@ pub mod pallet {
 				} else {
 					return Err(<Error<T>>::ContractNotFound.into())
 				};
-				<WasmBlob<T>>::increment_refcount(code_hash)?;
-				<WasmBlob<T>>::decrement_refcount(contract.code_hash);
+				<ExecStack<T, WasmBlob<T>>>::increment_refcount(code_hash)?;
+				<ExecStack<T, WasmBlob<T>>>::decrement_refcount(contract.code_hash);
 				Self::deposit_event(
 					vec![T::Hashing::hash_of(&dest), code_hash, contract.code_hash],
 					Event::ContractCodeUpdated {

substrate/frame/contracts/src/tests.rs

@@ -862,6 +862,27 @@ fn deposit_event_max_value_limit() {
 	});
 }
 
+// Fail out of fuel (ref_time weight) inside the start function.
+#[test]
+fn run_out_of_fuel_start_fun() {
+	let (wasm, _code_hash) = compile_module::<Test>("run_out_of_gas_start_fn").unwrap();
+	ExtBuilder::default().existential_deposit(50).build().execute_with(|| {
+		let _ = <Test as Config>::Currency::set_balance(&ALICE, 1_000_000);
+		assert_err_ignore_postinfo!(
+			Contracts::instantiate_with_code(
+				RuntimeOrigin::signed(ALICE),
+				0,
+				Weight::from_parts(1_000_000_000_000, u64::MAX),
+				None,
+				wasm,
+				vec![],
+				vec![],
+			),
+			Error::<Test>::OutOfGas,
+		);
+	});
+}
+
 // Fail out of fuel (ref_time weight) in the engine.
 #[test]
 fn run_out_of_fuel_engine() {