Support code delegation in instructions implementation

Author: gumb0

lib/evmone/instructions.hpp

@@ -4,6 +4,7 @@
 #pragma once
 
 #include "baseline.hpp"
+#include "constants.hpp"
 #include "eof.hpp"
 #include "execution_state.hpp"
 #include "instructions_traits.hpp"
@@ -128,6 +129,27 @@ inline bool check_memory(
     return check_memory(gas_left, memory, offset, static_cast<uint64_t>(size));
 }
 
+constexpr bool is_code_delegated(bytes_view code) noexcept
+{
+    return code.starts_with(DELEGATION_MAGIC);
+}
+
+inline std::optional<evmc::address> get_delegate_address(
+    const evmc::address& addr, const evmc::HostContext& host) noexcept
+{
+    std::array<uint8_t, std::size(DELEGATION_MAGIC)> prefix;
+    host.copy_code(addr, 0, prefix.data(), prefix.size());
+
+    if (!is_code_delegated(bytes_view{prefix.data(), prefix.size()}))
+        return {};
+
+    assert(host.get_code_size(addr) == std::size(DELEGATION_MAGIC) + std::size(addr.bytes));
+
+    evmc::address delegate_address;
+    host.copy_code(addr, prefix.size(), delegate_address.bytes, std::size(delegate_address.bytes));
+    return delegate_address;
+}
+
 namespace instr::core
 {
 
@@ -518,21 +540,34 @@ inline void blobbasefee(StackTop stack, ExecutionState& state) noexcept
 inline Result extcodesize(StackTop stack, int64_t gas_left, ExecutionState& state) noexcept
 {
     auto& x = stack.top();
-    const auto addr = intx::be::trunc<evmc::address>(x);
+    auto addr = intx::be::trunc<evmc::address>(x);
 
     if (state.rev >= EVMC_BERLIN && state.host.access_account(addr) == EVMC_ACCESS_COLD)
     {
         if ((gas_left -= instr::additional_cold_account_access_cost) < 0)
             return {EVMC_OUT_OF_GAS, gas_left};
     }
 
+    if (state.rev >= EVMC_PRAGUE)
+    {
+        if (const auto delegate_addr = get_delegate_address(addr, state.host))
+        {
+            addr = *delegate_addr;
+            if (state.host.access_account(addr) == EVMC_ACCESS_COLD)
+            {
+                if ((gas_left -= instr::additional_cold_account_access_cost) < 0)
+                    return {EVMC_OUT_OF_GAS, gas_left};
+            }
+        }
+    }
+
     x = state.host.get_code_size(addr);
     return {EVMC_SUCCESS, gas_left};
 }
 
 inline Result extcodecopy(StackTop stack, int64_t gas_left, ExecutionState& state) noexcept
 {
-    const auto addr = intx::be::trunc<evmc::address>(stack.pop());
+    auto addr = intx::be::trunc<evmc::address>(stack.pop());
     const auto& mem_index = stack.pop();
     const auto& input_index = stack.pop();
     const auto& size = stack.pop();
@@ -550,6 +585,19 @@ inline Result extcodecopy(StackTop stack, int64_t gas_left, ExecutionState& stat
             return {EVMC_OUT_OF_GAS, gas_left};
     }
 
+    if (state.rev >= EVMC_PRAGUE)
+    {
+        if (const auto delegate_addr = get_delegate_address(addr, state.host))
+        {
+            addr = *delegate_addr;
+            if (state.host.access_account(addr) == EVMC_ACCESS_COLD)
+            {
+                if ((gas_left -= instr::additional_cold_account_access_cost) < 0)
+                    return {EVMC_OUT_OF_GAS, gas_left};
+            }
+        }
+    }
+
     if (s > 0)
     {
         const auto src =
@@ -636,14 +684,27 @@ inline Result returndatacopy(StackTop stack, int64_t gas_left, ExecutionState& s
 inline Result extcodehash(StackTop stack, int64_t gas_left, ExecutionState& state) noexcept
 {
     auto& x = stack.top();
-    const auto addr = intx::be::trunc<evmc::address>(x);
+    auto addr = intx::be::trunc<evmc::address>(x);
 
     if (state.rev >= EVMC_BERLIN && state.host.access_account(addr) == EVMC_ACCESS_COLD)
     {
         if ((gas_left -= instr::additional_cold_account_access_cost) < 0)
             return {EVMC_OUT_OF_GAS, gas_left};
     }
 
+    if (state.rev >= EVMC_PRAGUE)
+    {
+        if (const auto delegate_addr = get_delegate_address(addr, state.host))
+        {
+            addr = *delegate_addr;
+            if (state.host.access_account(addr) == EVMC_ACCESS_COLD)
+            {
+                if ((gas_left -= instr::additional_cold_account_access_cost) < 0)
+                    return {EVMC_OUT_OF_GAS, gas_left};
+            }
+        }
+    }
+
     x = intx::be::load<uint256>(state.host.get_code_hash(addr));
     return {EVMC_SUCCESS, gas_left};
 }

lib/evmone/instructions_calls.cpp

@@ -50,7 +50,7 @@ Result call_impl(StackTop stack, int64_t gas_left, ExecutionState& state) noexce
         Op == OP_CALL || Op == OP_CALLCODE || Op == OP_DELEGATECALL || Op == OP_STATICCALL);
 
     const auto gas = stack.pop();
-    const auto dst = intx::be::trunc<evmc::address>(stack.pop());
+    auto dst = intx::be::trunc<evmc::address>(stack.pop());
     const auto value = (Op == OP_STATICCALL || Op == OP_DELEGATECALL) ? 0 : stack.pop();
     const auto has_value = value != 0;
     const auto input_offset_u256 = stack.pop();
@@ -67,6 +67,19 @@ Result call_impl(StackTop stack, int64_t gas_left, ExecutionState& state) noexce
             return {EVMC_OUT_OF_GAS, gas_left};
     }
 
+    if (state.rev >= EVMC_PRAGUE)
+    {
+        if (const auto delegate_addr = get_delegate_address(dst, state.host))
+        {
+            dst = *delegate_addr;
+            if (state.host.access_account(dst) == EVMC_ACCESS_COLD)
+            {
+                if ((gas_left -= instr::additional_cold_account_access_cost) < 0)
+                    return {EVMC_OUT_OF_GAS, gas_left};
+            }
+        }
+    }
+
     if (!check_memory(gas_left, state.memory, input_offset_u256, input_size_u256))
         return {EVMC_OUT_OF_GAS, gas_left};
 
@@ -170,14 +183,27 @@ Result extcall_impl(StackTop stack, int64_t gas_left, ExecutionState& state) noe
     if (dst_u256 > ADDRESS_MAX)
         return {EVMC_ARGUMENT_OUT_OF_RANGE, gas_left};
 
-    const auto dst = intx::be::trunc<evmc::address>(dst_u256);
+    auto dst = intx::be::trunc<evmc::address>(dst_u256);
 
     if (state.host.access_account(dst) == EVMC_ACCESS_COLD)
     {
         if ((gas_left -= instr::additional_cold_account_access_cost) < 0)
             return {EVMC_OUT_OF_GAS, gas_left};
     }
 
+    if (state.rev >= EVMC_PRAGUE)
+    {
+        if (const auto delegate_addr = get_delegate_address(dst, state.host))
+        {
+            dst = *delegate_addr;
+            if (state.host.access_account(dst) == EVMC_ACCESS_COLD)
+            {
+                if ((gas_left -= instr::additional_cold_account_access_cost) < 0)
+                    return {EVMC_OUT_OF_GAS, gas_left};
+            }
+        }
+    }
+
     if (!check_memory(gas_left, state.memory, input_offset_u256, input_size_u256))
         return {EVMC_OUT_OF_GAS, gas_left};