[pallet-revive] implement the gas limit API

prdoc/pr_6926.prdoc

@@ -0,0 +1,13 @@
+title: '[pallet-revive] implement the gas limit API'
+doc:
+- audience: Runtime Dev
+  description: This PR implements the gas limit API, returning the maximum ref_time
+    per block. Solidity contracts only know a single weight dimension and can use
+    this method to get the block ref_time limit.
+crates:
+- name: pallet-revive-fixtures
+  bump: major
+- name: pallet-revive
+  bump: major
+- name: pallet-revive-uapi
+  bump: major

substrate/frame/revive/fixtures/contracts/create_transient_storage_and_call.rs

@@ -22,7 +22,7 @@
 use common::input;
 use uapi::{HostFn, HostFnImpl as api, StorageFlags};
 
-static BUFFER: [u8; 512] = [0u8; 512];
+static BUFFER: [u8; 448] = [0u8; 448];
 
 #[no_mangle]
 #[polkavm_derive::polkavm_export]

substrate/frame/revive/fixtures/contracts/gas_limit.rs

@@ -0,0 +1,34 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Returns the block ref_time limit back to the caller.
+
+#![no_std]
+#![no_main]
+
+extern crate common;
+use uapi::{HostFn, HostFnImpl as api, ReturnFlags};
+
+#[no_mangle]
+#[polkavm_derive::polkavm_export]
+pub extern "C" fn deploy() {}
+
+#[no_mangle]
+#[polkavm_derive::polkavm_export]
+pub extern "C" fn call() {
+	api::return_value(ReturnFlags::empty(), &api::gas_limit().to_le_bytes());
+}

substrate/frame/revive/src/benchmarking/mod.rs

@@ -809,6 +809,17 @@ mod benchmarks {
 		assert_eq!(result.unwrap(), 128);
 	}
 
+	#[benchmark(pov_mode = Measured)]
+	fn seal_gas_limit() {
+		build_runtime!(runtime, memory: []);
+		let result;
+		#[block]
+		{
+			result = runtime.bench_gas_limit(&mut memory);
+		}
+		assert_eq!(result.unwrap(), T::BlockWeights::get().max_block.ref_time());
+	}
+
 	#[benchmark(pov_mode = Measured)]
 	fn seal_block_number() {
 		build_runtime!(runtime, memory: [[0u8;32], ]);

substrate/frame/revive/src/limits.rs

@@ -47,7 +47,7 @@ pub const NUM_EVENT_TOPICS: u32 = 4;
 pub const DELEGATE_DEPENDENCIES: u32 = 32;
 
 /// Maximum size of events (including topics) and storage values.
-pub const PAYLOAD_BYTES: u32 = 512;
+pub const PAYLOAD_BYTES: u32 = 448;
 
 /// The maximum size of the transient storage in bytes.
 ///

substrate/frame/revive/src/tests.rs

@@ -374,14 +374,15 @@ impl RegisteredChainExtension<Test> for TempStorageExtension {
 parameter_types! {
 	pub BlockWeights: frame_system::limits::BlockWeights =
 		frame_system::limits::BlockWeights::simple_max(
-			Weight::from_parts(2u64 * WEIGHT_REF_TIME_PER_SECOND, u64::MAX),
+			Weight::from_parts(2 * WEIGHT_REF_TIME_PER_SECOND, u64::MAX),
 		);
 	pub static ExistentialDeposit: u64 = 1;
 }
 
 #[derive_impl(frame_system::config_preludes::TestDefaultConfig)]
 impl frame_system::Config for Test {
 	type Block = Block;
+	type BlockWeights = BlockWeights;
 	type AccountId = AccountId32;
 	type Lookup = IdentityLookup<Self::AccountId>;
 	type AccountData = pallet_balances::AccountData<u64>;
@@ -438,7 +439,7 @@ parameter_types! {
 	pub static DepositPerByte: BalanceOf<Test> = 1;
 	pub const DepositPerItem: BalanceOf<Test> = 2;
 	pub static CodeHashLockupDepositPercent: Perbill = Perbill::from_percent(0);
-	pub static ChainId: u64 = 384;
+	pub static ChainId: u64 = 448;
 }
 
 impl Convert<Weight, BalanceOf<Self>> for Test {
@@ -3504,7 +3505,7 @@ fn deposit_limit_in_nested_calls() {
 		// Require more than the sender's balance.
 		// Limit the sub call to little balance so it should fail in there
 		let ret = builder::bare_call(addr_caller)
-			.data((512u32, &addr_callee, U256::from(1u64)).encode())
+			.data((448, &addr_callee, U256::from(1u64)).encode())
 			.build_and_unwrap_result();
 		assert_return_code!(ret, RuntimeReturnCode::OutOfResources);
 
@@ -4855,6 +4856,27 @@ fn skip_transfer_works() {
 	});
 }
 
+#[test]
+fn gas_limit_api_works() {
+	let (code, _) = compile_module("gas_limit").unwrap();
+
+	ExtBuilder::default().existential_deposit(100).build().execute_with(|| {
+		let _ = <Test as Config>::Currency::set_balance(&ALICE, 1_000_000);
+
+		// Create fixture: Constructor does nothing
+		let Contract { addr, .. } =
+			builder::bare_instantiate(Code::Upload(code)).build_and_unwrap_contract();
+
+		// Call the contract: It echoes back the value returned by the gas limit API.
+		let received = builder::bare_call(addr).build_and_unwrap_result();
+		assert_eq!(received.flags, ReturnFlags::empty());
+		assert_eq!(
+			u64::from_le_bytes(received.data[..].try_into().unwrap()),
+			<Test as frame_system::Config>::BlockWeights::get().max_block.ref_time()
+		);
+	});
+}
+
 #[test]
 fn unknown_syscall_rejected() {
 	let (code, _) = compile_module("unknown_syscall").unwrap();

substrate/frame/revive/src/wasm/runtime.rs

@@ -326,6 +326,8 @@ pub enum RuntimeCosts {
 	BlockHash,
 	/// Weight of calling `seal_now`.
 	Now,
+	/// Weight of calling `seal_gas_limit`.
+	GasLimit,
 	/// Weight of calling `seal_weight_to_fee`.
 	WeightToFee,
 	/// Weight of calling `seal_terminate`, passing the number of locked dependencies.
@@ -476,6 +478,7 @@ impl<T: Config> Token<T> for RuntimeCosts {
 			BlockNumber => T::WeightInfo::seal_block_number(),
 			BlockHash => T::WeightInfo::seal_block_hash(),
 			Now => T::WeightInfo::seal_now(),
+			GasLimit => T::WeightInfo::seal_gas_limit(),
 			WeightToFee => T::WeightInfo::seal_weight_to_fee(),
 			Terminate(locked_dependencies) => T::WeightInfo::seal_terminate(locked_dependencies),
 			DepositEvent { num_topic, len } => T::WeightInfo::seal_deposit_event(num_topic, len),
@@ -1538,6 +1541,14 @@ pub mod env {
 		)?)
 	}
 
+	/// Returns the block ref_time limit.
+	/// See [`pallet_revive_uapi::HostFn::gas_limit`].
+	#[stable]
+	fn gas_limit(&mut self, memory: &mut M) -> Result<u64, TrapReason> {
+		self.charge_gas(RuntimeCosts::GasLimit)?;
+		Ok(<E::T as frame_system::Config>::BlockWeights::get().max_block.ref_time())
+	}
+
 	/// Stores the value transferred along with this call/instantiate into the supplied buffer.
 	/// See [`pallet_revive_uapi::HostFn::value_transferred`].
 	#[stable]