EIP-7702: Set EOA account code

circle.yml

@@ -373,14 +373,13 @@ jobs:
           working_directory: ~/spec-tests/fixtures/state_tests
           command: >
             ~/build/bin/evmone-statetest ~/spec-tests/fixtures/state_tests
-            --gtest_filter='-*eip7702*'
       - 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 ~/spec-tests/fixtures/blockchain_tests
-            --gtest_filter='-*block_hashes.block_hashes_history:*eip7702*:*eip7623*'
+            --gtest_filter='-*block_hashes.block_hashes_history'
       - collect_coverage_gcc
       - upload_coverage:
           flags: execution_spec_tests

lib/evmone/CMakeLists.txt

@@ -17,6 +17,8 @@ add_library(evmone
     baseline_instruction_table.cpp
     baseline_instruction_table.hpp
     constants.hpp
+    delegation.cpp
+    delegation.hpp
     eof.cpp
     eof.hpp
     instructions.hpp

lib/evmone/delegation.cpp

@@ -0,0 +1,29 @@
+// evmone: Fast Ethereum Virtual Machine implementation
+// Copyright 2025 The evmone Authors.
+// SPDX-License-Identifier: Apache-2.0
+#include "delegation.hpp"
+#include <cassert>
+
+namespace evmone
+{
+std::optional<evmc::address> get_delegate_address(
+    const evmc::HostInterface& host, const evmc::address& addr) noexcept
+{
+    // Load the code prefix up to the delegation designation size.
+    // The HostInterface::copy_code() copies up to the addr's code size
+    // and returns the number of bytes copied.
+    uint8_t designation_buffer[std::size(DELEGATION_MAGIC) + sizeof(evmc::address)];
+    const auto size = host.copy_code(addr, 0, designation_buffer, std::size(designation_buffer));
+    const bytes_view designation{designation_buffer, size};
+
+    if (!is_code_delegated(designation))
+        return {};
+
+    // Copy the delegate address from the designation buffer.
+    evmc::address delegate_address;
+    // Assume the designation with the valid magic has also valid length.
+    assert(designation.size() == std::size(designation_buffer));
+    std::ranges::copy(designation.substr(std::size(DELEGATION_MAGIC)), delegate_address.bytes);
+    return delegate_address;
+}
+}  // namespace evmone

lib/evmone/delegation.hpp

@@ -0,0 +1,28 @@
+// evmone: Fast Ethereum Virtual Machine implementation
+// Copyright 2025 The evmone Authors.
+// SPDX-License-Identifier: Apache-2.0
+#pragma once
+
+#include <evmc/bytes.hpp>
+#include <evmc/evmc.hpp>
+#include <evmc/utils.h>
+
+namespace evmone
+{
+using evmc::bytes_view;
+
+/// Prefix of code for delegated accounts
+/// defined by [EIP-7702](https://eips.ethereum.org/EIPS/eip-7702)
+constexpr uint8_t DELEGATION_MAGIC_BYTES[] = {0xef, 0x01, 0x00};
+constexpr bytes_view DELEGATION_MAGIC{DELEGATION_MAGIC_BYTES, std::size(DELEGATION_MAGIC_BYTES)};
+
+/// Check if code contains EIP-7702 delegation designator
+constexpr bool is_code_delegated(bytes_view code) noexcept
+{
+    return code.starts_with(DELEGATION_MAGIC);
+}
+
+/// Get EIP-7702 delegate address from the code of addr, if it is delegated.
+EVMC_EXPORT std::optional<evmc::address> get_delegate_address(
+    const evmc::HostInterface& host, const evmc::address& addr) noexcept;
+}  // namespace evmone

lib/evmone/instructions_calls.cpp

@@ -2,6 +2,7 @@
 // Copyright 2019 The evmone Authors.
 // SPDX-License-Identifier: Apache-2.0
 
+#include "delegation.hpp"
 #include "eof.hpp"
 #include "instructions.hpp"
 
@@ -16,6 +17,34 @@
 
 namespace evmone::instr::core
 {
+namespace
+{
+/// Get target address of a code executing instruction.
+///
+/// Returns EIP-7702 delegate address if addr is delegated, or addr itself otherwise.
+/// Applies gas charge for accessing delegate account and may fail with out of gas.
+inline std::variant<evmc::address, Result> get_target_address(
+    const evmc::address& addr, int64_t& gas_left, ExecutionState& state) noexcept
+{
+    if (state.rev < EVMC_PRAGUE)
+        return addr;
+
+    const auto delegate_addr = get_delegate_address(state.host, addr);
+    if (!delegate_addr)
+        return addr;
+
+    const auto delegate_account_access_cost =
+        (state.host.access_account(*delegate_addr) == EVMC_ACCESS_COLD ?
+                instr::cold_account_access_cost :
+                instr::warm_storage_read_cost);
+
+    if ((gas_left -= delegate_account_access_cost) < 0)
+        return Result{EVMC_OUT_OF_GAS, gas_left};
+
+    return *delegate_addr;
+}
+}  // namespace
+
 /// Converts an opcode to matching EVMC call kind.
 /// NOLINTNEXTLINE(misc-use-internal-linkage) fixed in clang-tidy 20.
 consteval evmc_call_kind to_call_kind(Opcode op) noexcept
@@ -67,6 +96,12 @@
             return {EVMC_OUT_OF_GAS, gas_left};
     }
 
+    const auto target_addr_or_result = get_target_address(dst, gas_left, state);
+    if (const auto* result = std::get_if<Result>(&target_addr_or_result))
+        return *result;
+
+    const auto& code_addr = std::get<evmc::address>(target_addr_or_result);
+
     if (!check_memory(gas_left, state.memory, input_offset_u256, input_size_u256))
         return {EVMC_OUT_OF_GAS, gas_left};
 
@@ -80,9 +115,13 @@
 
     evmc_message msg{.kind = to_call_kind(Op)};
     msg.flags = (Op == OP_STATICCALL) ? uint32_t{EVMC_STATIC} : state.msg->flags;
+    if (dst != code_addr)
+        msg.flags |= EVMC_DELEGATED;
+    else
+        msg.flags &= ~std::underlying_type_t<evmc_flags>{EVMC_DELEGATED};
     msg.depth = state.msg->depth + 1;
     msg.recipient = (Op == OP_CALL || Op == OP_STATICCALL) ? dst : state.msg->recipient;
-    msg.code_address = dst;
+    msg.code_address = code_addr;
     msg.sender = (Op == OP_DELEGATECALL) ? state.msg->sender : state.msg->recipient;
     msg.value =
         (Op == OP_DELEGATECALL) ? state.msg->value : intx::be::store<evmc::uint256be>(value);
@@ -178,6 +217,12 @@
             return {EVMC_OUT_OF_GAS, gas_left};
     }
 
+    const auto target_addr_or_result = get_target_address(dst, gas_left, state);
+    if (const auto* result = std::get_if<Result>(&target_addr_or_result))
+        return *result;
+
+    const auto& code_addr = std::get<evmc::address>(target_addr_or_result);
+
     if (!check_memory(gas_left, state.memory, input_offset_u256, input_size_u256))
         return {EVMC_OUT_OF_GAS, gas_left};
 
@@ -186,9 +231,13 @@
 
     evmc_message msg{.kind = to_call_kind(Op)};
     msg.flags = (Op == OP_EXTSTATICCALL) ? uint32_t{EVMC_STATIC} : state.msg->flags;
+    if (dst != code_addr)
+        msg.flags |= EVMC_DELEGATED;
+    else
+        msg.flags &= ~std::underlying_type_t<evmc_flags>{EVMC_DELEGATED};
     msg.depth = state.msg->depth + 1;
     msg.recipient = (Op != OP_EXTDELEGATECALL) ? dst : state.msg->recipient;
-    msg.code_address = dst;
+    msg.code_address = code_addr;
     msg.sender = (Op == OP_EXTDELEGATECALL) ? state.msg->sender : state.msg->recipient;
     msg.value =
         (Op == OP_EXTDELEGATECALL) ? state.msg->value : intx::be::store<evmc::uint256be>(value);

test/state/errors.hpp

@@ -27,6 +27,8 @@
     EMPTY_BLOB_HASHES_LIST,
     INVALID_BLOB_HASH_VERSION,
     BLOB_GAS_LIMIT_EXCEEDED,
+    CREATE_SET_CODE_TX,
+    EMPTY_AUTHORIZATION_LIST,
     UNKNOWN_ERROR,
 };
 
@@ -73,6 +75,10 @@
                 return "invalid blob hash version";
             case BLOB_GAS_LIMIT_EXCEEDED:
                 return "blob gas limit exceeded";
+            case CREATE_SET_CODE_TX:
+                return "set code transaction must not be a create transaction";
+            case EMPTY_AUTHORIZATION_LIST:
+                return "empty authorization list";
             case UNKNOWN_ERROR:
                 return "Unknown error";
             default:

test/state/host.cpp

@@ -440,7 +440,8 @@ evmc::Result Host::execute_message(const evmc_message& msg) noexcept
         }
     }
 
-    if (is_precompile(m_rev, msg.code_address))
+    // Calls to precompile address via EIP-7702 delegation execute empty code instead of precompile.
+    if ((msg.flags & EVMC_DELEGATED) == 0 && is_precompile(m_rev, msg.code_address))
         return call_precompile(m_rev, msg);
 
     // TODO: get_code() performs the account lookup. Add a way to get an account with code?

test/state/precompiles_stubs.cpp

@@ -321,6 +321,7 @@ ExecutionResult expmod_stub(
             "0000000000000000000000000000000000000000000000000000000000000000"_hex},
         {0xd09419104ce1c64b6a06bcf063e98c2c91ad9e1beaf98b21c9d4734b4a3c9956_bytes32,
             "0000000000000000000000000000000000000000000000000000000000000000"_hex},
+        {0xd397b3b043d87fcd6fad1291ff0bfd16401c274896d8c63a923727f077b8e0b5_bytes32, ""_hex},
         {0xd6c0c03ec1f713b63be3d39b4fa8ef082b3407adc29baf74669fd2a574c638ac_bytes32, "01"_hex},
         {0xd837f9dcf93155fe558c02c7a660edc0cd238a8b8f95ee6b68e4a5c6a41fc70a_bytes32,
             "0000000000000000000000000000000000000000000000000000000000000001"_hex},