contracts: Charge rent for code storage (#7935)

* contracts: Implement refcounting for wasm code

* contracts: Charge rent for code storage

* contracts: Fix dispatchables erroneously refunding base costs

* Fixed typos in comments.

Co-authored-by: Andrew Jones <ascjones@gmail.com>

* Remove awkward empty line

* Fix more typos in docs

* Fix typos in docs

Co-authored-by: Andrew Jones <ascjones@gmail.com>

* Split up complicated expression

Co-authored-by: Andrew Jones <ascjones@gmail.com>

* review: Remove unused return value

* Fix typos

Co-authored-by: Andrew Jones <ascjones@gmail.com>

* review: Fix refcount being reset to one on re-instrumentation

* Document evictable_code parameter

* Make Executable::execute consume and store itself

* Added comments about stale values

* Disregard struct size in occupied_storage()

Co-authored-by: Andrew Jones <ascjones@gmail.com>

bin/node/executor/tests/basic.rs

@@ -602,23 +602,17 @@ fn deploying_wasm_contract_should_work() {
 			CheckedExtrinsic {
 				signed: Some((charlie(), signed_extra(0, 0))),
 				function: Call::Contracts(
-					pallet_contracts::Call::put_code::<Runtime>(transfer_code)
-				),
-			},
-			CheckedExtrinsic {
-				signed: Some((charlie(), signed_extra(1, 0))),
-				function: Call::Contracts(
-					pallet_contracts::Call::instantiate::<Runtime>(
-						1 * DOLLARS + subsistence,
+					pallet_contracts::Call::instantiate_with_code::<Runtime>(
+						1000 * DOLLARS + subsistence,
 						500_000_000,
-						transfer_ch,
+						transfer_code,
 						Vec::new(),
 						Vec::new(),
 					)
 				),
 			},
 			CheckedExtrinsic {
-				signed: Some((charlie(), signed_extra(2, 0))),
+				signed: Some((charlie(), signed_extra(1, 0))),
 				function: Call::Contracts(
 					pallet_contracts::Call::call::<Runtime>(
 						sp_runtime::MultiAddress::Id(addr.clone()),

frame/contracts/README.md

@@ -42,23 +42,19 @@ fails, A can decide how to handle that failure, either proceeding or reverting A
 
 ### Dispatchable functions
 
-* `put_code` - Stores the given binary Wasm code into the chain's storage and returns its `code_hash`.
-* `instantiate` - Deploys a new contract from the given `code_hash`, optionally transferring some balance.
-This instantiates a new smart contract account and calls its contract deploy handler to
-initialize the contract.
-* `call` - Makes a call to an account, optionally transferring some balance.
+Those are documented in the reference documentation of the `Module`.
 
 ## Usage
 
 The Contract module is a work in progress. The following examples show how this Contract module
 can be used to instantiate and call contracts.
 
-* [`ink`](https://github.com/paritytech/ink) is
+- [`ink`](https://github.com/paritytech/ink) is
 an [`eDSL`](https://wiki.haskell.org/Embedded_domain_specific_language) that enables writing
 WebAssembly based smart contracts in the Rust programming language. This is a work in progress.
 
 ## Related Modules
 
-* [Balances](https://docs.rs/pallet-balances/latest/pallet_balances/)
+- [Balances](https://docs.rs/pallet-balances/latest/pallet_balances/)
 
 License: Apache-2.0

frame/contracts/fixtures/instantiate_return_code.wat

@@ -10,8 +10,8 @@
 	(import "seal0" "seal_return" (func $seal_return (param i32 i32 i32)))
 	(import "env" "memory" (memory 1 1))
 
-	;; [0, 8) 100 balance
-	(data (i32.const 0) "\64\00\00\00\00\00\00\00")
+	;; [0, 8) 10_000 balance
+	(data (i32.const 0) "\10\27\00\00\00\00\00\00")
 
 	;; [8, 12) here we store the return code of the transfer
 

frame/contracts/src/benchmarking/code.rs

@@ -103,7 +103,7 @@ pub struct ImportedFunction {
 	pub return_type: Option<ValueType>,
 }
 
-/// A wasm module ready to be put on chain with `put_code`.
+/// A wasm module ready to be put on chain.
 #[derive(Clone)]
 pub struct WasmModule<T:Config> {
 	pub code: Vec<u8>,
@@ -245,16 +245,16 @@ where
 	}
 
 	/// Creates a wasm module of `target_bytes` size. Used to benchmark the performance of
-	/// `put_code` for different sizes of wasm modules. The generated module maximizes
+	/// `instantiate_with_code` for different sizes of wasm modules. The generated module maximizes
 	/// instrumentation runtime by nesting blocks as deeply as possible given the byte budget.
 	pub fn sized(target_bytes: u32) -> Self {
 		use parity_wasm::elements::Instruction::{If, I32Const, Return, End};
-		// Base size of a contract is 47 bytes and each expansion adds 6 bytes.
+		// Base size of a contract is 63 bytes and each expansion adds 6 bytes.
 		// We do one expansion less to account for the code section and function body
 		// size fields inside the binary wasm module representation which are leb128 encoded
 		// and therefore grow in size when the contract grows. We are not allowed to overshoot
-		// because of the maximum code size that is enforced by `put_code`.
-		let expansions = (target_bytes.saturating_sub(47) / 6).saturating_sub(1);
+		// because of the maximum code size that is enforced by `instantiate_with_code`.
+		let expansions = (target_bytes.saturating_sub(63) / 6).saturating_sub(1);
 		const EXPANSION: [Instruction; 4] = [
 			I32Const(0),
 			If(BlockType::NoResult),
@@ -263,6 +263,7 @@ where
 		];
 		ModuleDefinition {
 			call_body: Some(body::repeated(expansions, &EXPANSION)),
+			memory: Some(ImportedMemory::max::<T>()),
 			.. Default::default()
 		}
 		.into()

frame/contracts/src/benchmarking/mod.rs

@@ -137,7 +137,7 @@ where
 		// same block number.
 		System::<T>::set_block_number(1u32.into());
 
-		Contracts::<T>::put_code_raw(module.code)?;
+		Contracts::<T>::store_code_raw(module.code)?;
 		Contracts::<T>::instantiate(
 			RawOrigin::Signed(caller.clone()).into(),
 			endowment,
@@ -198,7 +198,7 @@ where
 	/// Get the block number when this contract will be evicted. Returns an error when
 	/// the rent collection won't happen because the contract has to much endowment.
 	fn eviction_at(&self) -> Result<T::BlockNumber, &'static str> {
-		let projection = Rent::<T>::compute_projection(&self.account_id)
+		let projection = Rent::<T, PrefabWasmModule<T>>::compute_projection(&self.account_id)
 			.map_err(|_| "Invalid acc for rent")?;
 		match projection {
 			RentProjection::EvictionAt(at) => Ok(at),
@@ -250,7 +250,7 @@ where
 	/// Evict this contract.
 	fn evict(&mut self) -> Result<(), &'static str> {
 		self.set_block_num_for_eviction()?;
-		Rent::<T>::try_eviction(&self.contract.account_id, Zero::zero())?;
+		Rent::<T, PrefabWasmModule<T>>::try_eviction(&self.contract.account_id, Zero::zero())?;
 		self.contract.ensure_tombstone()
 	}
 }
@@ -314,33 +314,43 @@ benchmarks! {
 
 	// This constructs a contract that is maximal expensive to instrument.
 	// It creates a maximum number of metering blocks per byte.
-	// `n`: Size of the code in kilobytes.
-	put_code {
-		let n in 0 .. Contracts::<T>::current_schedule().limits.code_size / 1024;
+	// The size of the salt influences the runtime because is is hashed in order to
+	// determine the contract address.
+	// `c`: Size of the code in kilobytes.
+	// `s`: Size of the salt in kilobytes.
+	instantiate_with_code {
+		let c in 0 .. Contracts::<T>::current_schedule().limits.code_size / 1024;
+		let s in 0 .. code::max_pages::<T>() * 64;
+		let salt = vec![42u8; (s * 1024) as usize];
+		let endowment = caller_funding::<T>() / 3u32.into();
 		let caller = whitelisted_caller();
 		T::Currency::make_free_balance_be(&caller, caller_funding::<T>());
-		let module = WasmModule::<T>::sized(n * 1024);
-		let origin = RawOrigin::Signed(caller);
-	}: _(origin, module.code)
+		let WasmModule { code, hash, .. } = WasmModule::<T>::sized(c * 1024);
+		let origin = RawOrigin::Signed(caller.clone());
+		let addr = Contracts::<T>::contract_address(&caller, &hash, &salt);
+	}: _(origin, endowment, Weight::max_value(), code, vec![], salt)
+	verify {
+		// endowment was removed from the caller
+		assert_eq!(T::Currency::free_balance(&caller), caller_funding::<T>() - endowment);
+		// contract has the full endowment because no rent collection happended
+		assert_eq!(T::Currency::free_balance(&addr), endowment);
+		// instantiate should leave a alive contract
+		Contract::<T>::address_alive_info(&addr)?;
+	}
 
 	// Instantiate uses a dummy contract constructor to measure the overhead of the instantiate.
-	// The size of the input data influences the runtime because it is hashed in order to determine
-	// the contract address.
-	// `n`: Size of the data passed to constructor in kilobytes.
 	// `s`: Size of the salt in kilobytes.
 	instantiate {
-		let n in 0 .. code::max_pages::<T>() * 64;
 		let s in 0 .. code::max_pages::<T>() * 64;
-		let data = vec![42u8; (n * 1024) as usize];
 		let salt = vec![42u8; (s * 1024) as usize];
 		let endowment = caller_funding::<T>() / 3u32.into();
 		let caller = whitelisted_caller();
 		T::Currency::make_free_balance_be(&caller, caller_funding::<T>());
 		let WasmModule { code, hash, .. } = WasmModule::<T>::dummy_with_mem();
 		let origin = RawOrigin::Signed(caller.clone());
 		let addr = Contracts::<T>::contract_address(&caller, &hash, &salt);
-		Contracts::<T>::put_code_raw(code)?;
-	}: _(origin, endowment, Weight::max_value(), hash, data, salt)
+		Contracts::<T>::store_code_raw(code)?;
+	}: _(origin, endowment, Weight::max_value(), hash, vec![], salt)
 	verify {
 		// endowment was removed from the caller
 		assert_eq!(T::Currency::free_balance(&caller), caller_funding::<T>() - endowment);
@@ -1369,7 +1379,7 @@ benchmarks! {
 					])),
 					.. Default::default()
 				});
-				Contracts::<T>::put_code_raw(code.code)?;
+				Contracts::<T>::store_code_raw(code.code)?;
 				Ok(code.hash)
 			})
 			.collect::<Result<Vec<_>, &'static str>>()?;
@@ -1492,7 +1502,7 @@ benchmarks! {
 		let hash = callee_code.hash.clone();
 		let hash_bytes = callee_code.hash.encode();
 		let hash_len = hash_bytes.len();
-		Contracts::<T>::put_code_raw(callee_code.code)?;
+		Contracts::<T>::store_code_raw(callee_code.code)?;
 		let inputs = (0..API_BENCHMARK_BATCH_SIZE).map(|x| x.encode()).collect::<Vec<_>>();
 		let input_len = inputs.get(0).map(|x| x.len()).unwrap_or(0);
 		let input_bytes = inputs.iter().cloned().flatten().collect::<Vec<_>>();
@@ -2455,7 +2465,7 @@ mod tests {
 	create_test!(on_initialize_per_queue_item);
 
 	create_test!(update_schedule);
-	create_test!(put_code);
+	create_test!(instantiate_with_code);
 	create_test!(instantiate);
 	create_test!(call);
 	create_test!(claim_surcharge);