EIP-2935: Serve historical block hashes from state (#953)

Implement [EIP-2935](https://eips.ethereum.org/EIPS/eip-2935) "Serve
historical block hashes from state" required for the
[Prague](https://eips.ethereum.org/EIPS/eip-7600) revision.
This mostly adds new system contract.

circle.yml

@@ -371,9 +371,16 @@ jobs:
           # Tests for in-development EVM revision currently passing.
           working_directory: ~/spec-tests/fixtures/state_tests
           command: >
-            ~/build/bin/evmone-statetest 
+            ~/build/bin/evmone-statetest
             prague/eip2537_bls_12_381_precompiles/bls12_precompiles_before_fork
             prague/eip2537_bls_12_381_precompiles/bls12_g1add
+      - run:
+          name: "Execution spec tests (develop, blockchain_tests)"
+          # Tests for in-development EVM revision currently passing.
+          working_directory: ~/spec-tests/fixtures/blockchain_tests
+          command: >
+            ~/build/bin/evmone-blockchaintest
+            prague/eip2935_historical_block_hashes_from_state
       - collect_coverage_gcc
       - upload_coverage:
           flags: execution_spec_tests

test/state/system_contracts.cpp

@@ -24,6 +24,10 @@ struct SystemContract
 constexpr std::array SYSTEM_CONTRACTS{
     SystemContract{EVMC_CANCUN, BEACON_ROOTS_ADDRESS,
         [](const BlockInfo& block) noexcept { return bytes_view{block.parent_beacon_block_root}; }},
+    SystemContract{EVMC_PRAGUE, HISTORY_STORAGE_ADDRESS,
+        [](const BlockInfo& block) noexcept {
+            return bytes_view{block.known_block_hashes.at(block.number - 1)};
+        }},
 };
 
 static_assert(std::ranges::is_sorted(SYSTEM_CONTRACTS,

test/state/system_contracts.hpp

@@ -15,6 +15,9 @@ constexpr auto SYSTEM_ADDRESS = 0xfffffffffffffffffffffffffffffffffffffffe_addre
 /// The address of the system contract storing the root hashes of beacon chain blocks (EIP-4788).
 constexpr auto BEACON_ROOTS_ADDRESS = 0x000F3df6D732807Ef1319fB7B8bB8522d0Beac02_address;
 
+/// The address of the system contract storing historical block hashes (EIP-2935).
+constexpr auto HISTORY_STORAGE_ADDRESS = 0x0aae40965e6800cd9b1f4b05ff21581047e3f91e_address;
+
 struct BlockInfo;
 class State;
 

test/unittests/state_system_call_test.cpp

@@ -44,3 +44,23 @@ TEST_F(state_system_call, beacon_roots)
     EXPECT_EQ(storage.at(0x01_bytes32).current, block.parent_beacon_block_root);
     EXPECT_EQ(storage.at(0x00_bytes32).current, to_bytes32(SYSTEM_ADDRESS));
 }
+
+TEST_F(state_system_call, history_storage)
+{
+    static constexpr auto NUMBER = 123456789;
+    static constexpr auto PREV_BLOCKHASH = 0xbbbb_bytes32;
+    const BlockInfo block{.number = NUMBER, .known_block_hashes = {{NUMBER - 1, PREV_BLOCKHASH}}};
+    state.insert(HISTORY_STORAGE_ADDRESS,
+        {.code = sstore(OP_NUMBER, calldataload(0)) + sstore(0, OP_CALLER)});
+
+    system_call(state, block, EVMC_PRAGUE, vm);
+
+    ASSERT_EQ(state.get_accounts().size(), 1);
+    EXPECT_EQ(state.find(SYSTEM_ADDRESS), nullptr);
+    EXPECT_EQ(state.get(HISTORY_STORAGE_ADDRESS).nonce, 0);
+    EXPECT_EQ(state.get(HISTORY_STORAGE_ADDRESS).balance, 0);
+    const auto& storage = state.get(HISTORY_STORAGE_ADDRESS).storage;
+    ASSERT_EQ(storage.size(), 2);
+    EXPECT_EQ(storage.at(bytes32{NUMBER}).current, PREV_BLOCKHASH);
+    EXPECT_EQ(storage.at(0x00_bytes32).current, to_bytes32(SYSTEM_ADDRESS));
+}

test/utils/utils.cpp

@@ -46,6 +46,8 @@ RevisionSchedule to_rev_schedule(std::string_view s)
 {
     if (s == "ShanghaiToCancunAtTime15k")
         return {EVMC_SHANGHAI, EVMC_CANCUN, 15'000};
+    if (s == "CancunToPragueAtTime15k")
+        return {EVMC_CANCUN, EVMC_PRAGUE, 15'000};
 
     const auto single_rev = to_rev(s);
     return {single_rev, single_rev, 0};