Allow for precompiles to have arbitrary addresses, potentially more than one.

frame/evm/precompile/dispatch/src/tests.rs

@@ -73,8 +73,14 @@ pub fn new_test_ext() -> sp_io::TestExternalities {
 	}
 	.assimilate_storage(&mut t)
 	.expect("Pallet balances storage can be assimilated");
-	GenesisBuild::<Test>::assimilate_storage(&pallet_evm::GenesisConfig { accounts }, &mut t)
-		.unwrap();
+	GenesisBuild::<Test>::assimilate_storage(
+		&pallet_evm::GenesisConfig {
+			accounts,
+			precompiles: vec![],
+		},
+		&mut t,
+	)
+	.unwrap();
 	t.into()
 }
 

frame/evm/src/lib.rs

@@ -467,6 +467,7 @@ pub mod pallet {
 	#[cfg_attr(feature = "std", derive(Default))]
 	pub struct GenesisConfig {
 		pub accounts: std::collections::BTreeMap<H160, GenesisAccount>,
+		pub precompiles: Vec<(Vec<u8>, H160)>,
 	}
 
 	#[pallet::genesis_build]
@@ -497,6 +498,10 @@ pub mod pallet {
 					<AccountStorages<T>>::insert(address, index, value);
 				}
 			}
+
+			for (label, address) in &self.precompiles {
+				Pallet::<T>::add_precompile(label, address);
+			}
 		}
 	}
 
@@ -508,6 +513,17 @@ pub mod pallet {
 	#[pallet::getter(fn account_storages)]
 	pub type AccountStorages<T: Config> =
 		StorageDoubleMap<_, Blake2_128Concat, H160, Blake2_128Concat, H256, H256, ValueQuery>;
+
+	/// Allows for precompiles to have arbitrary addresses, potentially more than one.
+	/// `k1`: precompile label, e.g.: `b"Sha3FIPS256".to_vec()`
+	/// `k2`: precompile address
+	///
+	/// Please note that adding a new precompile label here is not enough to guarantee its execution
+	/// It is also required to list the new label on the implementation of `PrecompileSet::execute()`
+	#[pallet::storage]
+	#[pallet::getter(fn precompiles)]
+	pub type Precompiles<T: Config> =
+		StorageDoubleMap<_, Blake2_128Concat, Vec<u8>, Blake2_128Concat, H160, (), OptionQuery>;
 }
 
 /// Type alias for currency balance.
@@ -671,6 +687,16 @@ impl<T: Config> GasWeightMapping for FixedGasWeightMapping<T> {
 static LONDON_CONFIG: EvmConfig = EvmConfig::london();
 
 impl<T: Config> Pallet<T> {
+	/// Add a precompile to storage
+	pub fn add_precompile(label: &Vec<u8>, address: &H160) {
+		Precompiles::<T>::set(label, address, Some(()));
+	}
+
+	/// Remove a precompile from storage
+	pub fn remove_precompile(label: &Vec<u8>, address: &H160) {
+		Precompiles::<T>::remove(label, address);
+	}
+
 	/// Check whether an account is empty.
 	pub fn is_account_empty(address: &H160) -> bool {
 		let (account, _) = Self::account_basic(address);

frame/evm/src/tests.rs

@@ -67,6 +67,8 @@ pub fn new_test_ext() -> sp_io::TestExternalities {
 		},
 	);
 
+	let precompiles = vec![];
+
 	pallet_balances::GenesisConfig::<Test> {
 		// Create the block author account with some balance.
 		balances: vec![(
@@ -76,7 +78,14 @@ pub fn new_test_ext() -> sp_io::TestExternalities {
 	}
 	.assimilate_storage(&mut t)
 	.expect("Pallet balances storage can be assimilated");
-	GenesisBuild::<Test>::assimilate_storage(&crate::GenesisConfig { accounts }, &mut t).unwrap();
+	GenesisBuild::<Test>::assimilate_storage(
+		&crate::GenesisConfig {
+			accounts,
+			precompiles,
+		},
+		&mut t,
+	)
+	.unwrap();
 	t.into()
 }
 

template/node/src/chain_spec.rs

@@ -250,6 +250,17 @@ fn testnet_genesis(
 				);
 				map
 			},
+			precompiles: vec![
+				// Ethereum precompiles :
+				(b"ECRecover".to_vec(), H160::from_low_u64_be(1)),
+				(b"Sha256".to_vec(), H160::from_low_u64_be(2)),
+				(b"Ripemd160".to_vec(), H160::from_low_u64_be(3)),
+				(b"Identity".to_vec(), H160::from_low_u64_be(4)),
+				(b"Modexp".to_vec(), H160::from_low_u64_be(5)),
+				// Non-Frontier specific nor Ethereum precompiles :
+				(b"Sha3FIPS256".to_vec(), H160::from_low_u64_be(1024)),
+				(b"Sha3FIPS256".to_vec(), H160::from_low_u64_be(1025)),
+			],
 		},
 		ethereum: Default::default(),
 		dynamic_fee: Default::default(),

template/runtime/src/precompiles.rs

@@ -2,6 +2,7 @@ use pallet_evm::{Precompile, PrecompileHandle, PrecompileResult, PrecompileSet};
 use sp_core::H160;
 use sp_std::marker::PhantomData;
 
+use pallet_evm::Precompiles;
 use pallet_evm_precompile_modexp::Modexp;
 use pallet_evm_precompile_sha3fips::Sha3FIPS256;
 use pallet_evm_precompile_simple::{ECRecover, ECRecoverPublicKey, Identity, Ripemd160, Sha256};
@@ -15,17 +16,6 @@ where
 	pub fn new() -> Self {
 		Self(Default::default())
 	}
-	pub fn used_addresses() -> [H160; 7] {
-		[
-			hash(1),
-			hash(2),
-			hash(3),
-			hash(4),
-			hash(5),
-			hash(1024),
-			hash(1025),
-		]
-	}
 }
 impl<R> PrecompileSet for FrontierPrecompiles<R>
 where
@@ -34,23 +24,42 @@ where
 	fn execute(&self, handle: &mut impl PrecompileHandle) -> Option<PrecompileResult> {
 		match handle.code_address() {
 			// Ethereum precompiles :
-			a if a == hash(1) => Some(ECRecover::execute(handle)),
-			a if a == hash(2) => Some(Sha256::execute(handle)),
-			a if a == hash(3) => Some(Ripemd160::execute(handle)),
-			a if a == hash(4) => Some(Identity::execute(handle)),
-			a if a == hash(5) => Some(Modexp::execute(handle)),
+			a if Precompiles::<R>::contains_key(b"ECRecover".to_vec(), a) => {
+				Some(ECRecover::execute(handle))
+			}
+			a if Precompiles::<R>::contains_key(b"Sha256".to_vec(), a) => {
+				Some(Sha256::execute(handle))
+			}
+			a if Precompiles::<R>::contains_key(b"Ripemd160".to_vec(), a) => {
+				Some(Ripemd160::execute(handle))
+			}
+			a if Precompiles::<R>::contains_key(b"Identity".to_vec(), a) => {
+				Some(Identity::execute(handle))
+			}
+			a if Precompiles::<R>::contains_key(b"Modexp".to_vec(), a) => {
+				Some(Modexp::execute(handle))
+			}
 			// Non-Frontier specific nor Ethereum precompiles :
-			a if a == hash(1024) => Some(Sha3FIPS256::execute(handle)),
-			a if a == hash(1025) => Some(ECRecoverPublicKey::execute(handle)),
+			a if Precompiles::<R>::contains_key(b"Sha3FIPS256".to_vec(), a) => {
+				Some(Sha3FIPS256::execute(handle))
+			}
+			a if Precompiles::<R>::contains_key(b"ECRecoverPublicKey".to_vec(), a) => {
+				Some(ECRecoverPublicKey::execute(handle))
+			}
 			_ => None,
 		}
 	}
 
 	fn is_precompile(&self, address: H160) -> bool {
-		Self::used_addresses().contains(&address)
+		match address {
+			a if Precompiles::<R>::contains_key(b"ECRecover".to_vec(), a) => true,
+			a if Precompiles::<R>::contains_key(b"Sha256".to_vec(), a) => true,
+			a if Precompiles::<R>::contains_key(b"Ripemd160".to_vec(), a) => true,
+			a if Precompiles::<R>::contains_key(b"Identity".to_vec(), a) => true,
+			a if Precompiles::<R>::contains_key(b"Modexp".to_vec(), a) => true,
+			a if Precompiles::<R>::contains_key(b"Sha3FIPS256".to_vec(), a) => true,
+			a if Precompiles::<R>::contains_key(b"ECRecoverPublicKey".to_vec(), a) => true,
+			_ => false,
+		}
 	}
 }
-
-fn hash(a: u64) -> H160 {
-	H160::from_low_u64_be(a)
-}