[pallet-revive] Add host function to_account_id (#7091)

Closes #6891.

cc @athei @xermicus @pgherveou

prdoc/pr_7091.prdoc

@@ -0,0 +1,12 @@
+title: '[pallet-revive] Add new host function `to_account_id`'
+doc:
+- audience: Runtime Dev
+  description: A new host function `to_account_id` is added. It allows retrieving
+    the account id for a `H160` address.
+crates:
+- name: pallet-revive-fixtures
+  bump: minor
+- name: pallet-revive
+  bump: minor
+- name: pallet-revive-uapi
+  bump: minor

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

@@ -0,0 +1,40 @@
+// 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.
+
+#![no_std]
+#![no_main]
+
+use common::input;
+use uapi::{HostFn, HostFnImpl as api};
+
+#[no_mangle]
+#[polkavm_derive::polkavm_export]
+pub extern "C" fn deploy() {}
+
+#[no_mangle]
+#[polkavm_derive::polkavm_export]
+pub extern "C" fn call() {
+    input!(
+        address: &[u8; 20],
+        expected_account_id: &[u8; 32],
+    );
+
+    let mut account_id = [0u8; 32];
+    api::to_account_id(address, &mut account_id);
+
+    assert!(&account_id == expected_account_id);
+}

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

@@ -556,6 +556,38 @@ mod benchmarks {
 		assert_eq!(result.unwrap(), 1);
 	}
 
+	#[benchmark(pov_mode = Measured)]
+	fn seal_to_account_id() {
+		// use a mapped address for the benchmark, to ensure that we bench the worst
+		// case (and not the fallback case).
+		let address = {
+			let caller = account("seal_to_account_id", 0, 0);
+			T::Currency::set_balance(&caller, caller_funding::<T>());
+			T::AddressMapper::map(&caller).unwrap();
+			T::AddressMapper::to_address(&caller)
+		};
+
+		let len = <T::AccountId as MaxEncodedLen>::max_encoded_len();
+		build_runtime!(runtime, memory: [vec![0u8; len], address.0, ]);
+
+		let result;
+		#[block]
+		{
+			result = runtime.bench_to_account_id(memory.as_mut_slice(), len as u32, 0);
+		}
+
+		assert_ok!(result);
+		assert_ne!(
+			memory.as_slice()[20..32],
+			[0xEE; 12],
+			"fallback suffix found where none should be"
+		);
+		assert_eq!(
+			T::AccountId::decode(&mut memory.as_slice()),
+			Ok(runtime.ext().to_account_id(&address))
+		);
+	}
+
 	#[benchmark(pov_mode = Measured)]
 	fn seal_code_hash() {
 		let contract = Contract::<T>::with_index(1, WasmModule::dummy(), vec![]).unwrap();

substrate/frame/revive/src/exec.rs

@@ -293,6 +293,9 @@ pub trait Ext: sealing::Sealed {
 	/// Check if a contract lives at the specified `address`.
 	fn is_contract(&self, address: &H160) -> bool;
 
+	/// Returns the account id for the given `address`.
+	fn to_account_id(&self, address: &H160) -> AccountIdOf<Self::T>;
+
 	/// Returns the code hash of the contract for the given `address`.
 	/// If not a contract but account exists then `keccak_256([])` is returned, otherwise `zero`.
 	fn code_hash(&self, address: &H160) -> H256;
@@ -1572,6 +1575,10 @@ where
 		ContractInfoOf::<T>::contains_key(&address)
 	}
 
+	fn to_account_id(&self, address: &H160) -> T::AccountId {
+		T::AddressMapper::to_account_id(address)
+	}
+
 	fn code_hash(&self, address: &H160) -> H256 {
 		<ContractInfoOf<T>>::get(&address)
 			.map(|contract| contract.code_hash)
@@ -2582,6 +2589,40 @@ mod tests {
 		});
 	}
 
+	#[test]
+	fn to_account_id_returns_proper_values() {
+		let bob_code_hash = MockLoader::insert(Call, |ctx, _| {
+			let alice_account_id = <Test as Config>::AddressMapper::to_account_id(&ALICE_ADDR);
+			assert_eq!(ctx.ext.to_account_id(&ALICE_ADDR), alice_account_id);
+
+			const UNMAPPED_ADDR: H160 = H160([99u8; 20]);
+			let mut unmapped_fallback_account_id = [0xEE; 32];
+			unmapped_fallback_account_id[..20].copy_from_slice(UNMAPPED_ADDR.as_bytes());
+			assert_eq!(
+				ctx.ext.to_account_id(&UNMAPPED_ADDR),
+				AccountId32::new(unmapped_fallback_account_id)
+			);
+
+			exec_success()
+		});
+
+		ExtBuilder::default().build().execute_with(|| {
+			place_contract(&BOB, bob_code_hash);
+			let origin = Origin::from_account_id(ALICE);
+			let mut storage_meter = storage::meter::Meter::new(&origin, 0, 0).unwrap();
+			let result = MockStack::run_call(
+				origin,
+				BOB_ADDR,
+				&mut GasMeter::<Test>::new(GAS_LIMIT),
+				&mut storage_meter,
+				U256::zero(),
+				vec![0],
+				false,
+			);
+			assert_matches!(result, Ok(_));
+		});
+	}
+
 	#[test]
 	fn code_hash_returns_proper_values() {
 		let bob_code_hash = MockLoader::insert(Call, |ctx, _| {

substrate/frame/revive/src/tests.rs

@@ -4239,6 +4239,43 @@ fn origin_api_works() {
 	});
 }
 
+#[test]
+fn to_account_id_works() {
+	let (code_hash_code, _) = compile_module("to_account_id").unwrap();
+
+	ExtBuilder::default().existential_deposit(1).build().execute_with(|| {
+		let _ = <Test as Config>::Currency::set_balance(&ALICE, 1_000_000);
+		let _ = <Test as Config>::Currency::set_balance(&EVE, 1_000_000);
+
+		let Contract { addr, .. } =
+			builder::bare_instantiate(Code::Upload(code_hash_code)).build_and_unwrap_contract();
+
+		// mapped account
+		<Pallet<Test>>::map_account(RuntimeOrigin::signed(EVE)).unwrap();
+		let expected_mapped_account_id = &<Test as Config>::AddressMapper::to_account_id(&EVE_ADDR);
+		assert_ne!(
+			expected_mapped_account_id.encode()[20..32],
+			[0xEE; 12],
+			"fallback suffix found where none should be"
+		);
+		assert_ok!(builder::call(addr)
+			.data((EVE_ADDR, expected_mapped_account_id).encode())
+			.build());
+
+		// fallback for unmapped accounts
+		let expected_fallback_account_id =
+			&<Test as Config>::AddressMapper::to_account_id(&BOB_ADDR);
+		assert_eq!(
+			expected_fallback_account_id.encode()[20..32],
+			[0xEE; 12],
+			"no fallback suffix found where one should be"
+		);
+		assert_ok!(builder::call(addr)
+			.data((BOB_ADDR, expected_fallback_account_id).encode())
+			.build());
+	});
+}
+
 #[test]
 fn code_hash_works() {
 	let (code_hash_code, self_code_hash) = compile_module("code_hash").unwrap();

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

@@ -293,6 +293,8 @@ pub enum RuntimeCosts {
 	CallDataSize,
 	/// Weight of calling `seal_return_data_size`.
 	ReturnDataSize,
+	/// Weight of calling `seal_to_account_id`.
+	ToAccountId,
 	/// Weight of calling `seal_origin`.
 	Origin,
 	/// Weight of calling `seal_is_contract`.
@@ -466,6 +468,7 @@ impl<T: Config> Token<T> for RuntimeCosts {
 			Caller => T::WeightInfo::seal_caller(),
 			Origin => T::WeightInfo::seal_origin(),
 			IsContract => T::WeightInfo::seal_is_contract(),
+			ToAccountId => T::WeightInfo::seal_to_account_id(),
 			CodeHash => T::WeightInfo::seal_code_hash(),
 			CodeSize => T::WeightInfo::seal_code_size(),
 			OwnCodeHash => T::WeightInfo::seal_own_code_hash(),
@@ -2140,4 +2143,25 @@ pub mod env {
 			},
 		}
 	}
+
+	/// Retrieves the account id for a specified contract address.
+	///
+	/// See [`pallet_revive_uapi::HostFn::to_account_id`].
+	fn to_account_id(
+		&mut self,
+		memory: &mut M,
+		addr_ptr: u32,
+		out_ptr: u32,
+	) -> Result<(), TrapReason> {
+		self.charge_gas(RuntimeCosts::ToAccountId)?;
+		let address = memory.read_h160(addr_ptr)?;
+		let account_id = self.ext.to_account_id(&address);
+		Ok(self.write_fixed_sandbox_output(
+			memory,
+			out_ptr,
+			&account_id.encode(),
+			false,
+			already_charged,
+		)?)
+	}
 }

substrate/frame/revive/uapi/src/host.rs

@@ -144,6 +144,18 @@ pub trait HostFn: private::Sealed {
 	/// - `output`: A reference to the output data buffer to write the origin's address.
 	fn origin(output: &mut [u8; 20]);
 
+	/// Retrieve the account id for a specified address.
+	///
+	/// # Parameters
+	///
+	/// - `addr`: A `H160` address.
+	/// - `output`: A reference to the output data buffer to write the account id.
+	///
+	/// # Note
+	///
+	/// If no mapping exists for `addr`, the fallback account id will be returned.
+	fn to_account_id(addr: &[u8; 20], output: &mut [u8]);
+
 	/// Retrieve the code hash for a specified contract address.
 	///
 	/// # Parameters

substrate/frame/revive/uapi/src/host/riscv64.rs

@@ -69,6 +69,7 @@ mod sys {
 		pub fn caller(out_ptr: *mut u8);
 		pub fn origin(out_ptr: *mut u8);
 		pub fn is_contract(account_ptr: *const u8) -> ReturnCode;
+		pub fn to_account_id(address_ptr: *const u8, out_ptr: *mut u8);
 		pub fn code_hash(address_ptr: *const u8, out_ptr: *mut u8);
 		pub fn code_size(address_ptr: *const u8) -> u64;
 		pub fn own_code_hash(out_ptr: *mut u8);
@@ -456,6 +457,11 @@ impl HostFn for HostFnImpl {
 		unsafe { sys::ref_time_left() }
 	}
 
+	#[unstable_hostfn]
+	fn to_account_id(address: &[u8; 20], output: &mut [u8]) {
+		unsafe { sys::to_account_id(address.as_ptr(), output.as_mut_ptr()) }
+	}
+
 	#[unstable_hostfn]
 	fn block_hash(block_number_ptr: &[u8; 32], output: &mut [u8; 32]) {
 		unsafe { sys::block_hash(block_number_ptr.as_ptr(), output.as_mut_ptr()) };