evm: refactor bailout option handling

Implement the bailout option by pure state modification before
the transaction validation and execution.

silkworm/core/execution/processor.cpp

@@ -264,10 +264,6 @@ CallResult ExecutionProcessor::call(const Transaction& txn, const std::vector<st
 
     SILKWORM_ASSERT(protocol::validate_call_precheck(txn, evm_) == ValidationResult::kOk);
 
-    if (!evm().bailout) {
-        SILKWORM_ASSERT(protocol::validate_call_funds(txn, evm_, state_.get_balance(*txn.sender())) == ValidationResult::kOk);
-    }
-
     const BlockHeader& header{evm_.block().header};
     const intx::uint256 base_fee_per_gas{header.base_fee_per_gas.value_or(0)};
 
@@ -284,10 +280,15 @@ CallResult ExecutionProcessor::call(const Transaction& txn, const std::vector<st
         state_.set_nonce(*sender, state_.get_nonce(*txn.sender()) + 1);
     }
 
-    if (!evm().bailout) {
-        const intx::uint256 required_funds = protocol::compute_call_cost(txn, effective_gas_price, evm_);
-        state_.subtract_from_balance(*txn.sender(), required_funds);
+    const intx::uint256 required_funds = protocol::compute_call_cost(txn, effective_gas_price, evm_);
+    if (evm().bailout) {
+        // If the bailout option is on, add the required funds to the sender's balance
+        // so that after the transaction costs are deducted, the sender's balance is unchanged.
+        state_.add_to_balance(*txn.sender(), required_funds);
     }
+
+    SILKWORM_ASSERT(protocol::validate_call_funds(txn, evm_, state_.get_balance(*txn.sender())) == ValidationResult::kOk);
+    state_.subtract_from_balance(*txn.sender(), required_funds);
     const intx::uint128 g0{protocol::intrinsic_gas(txn, evm_.revision())};
     const auto result = evm_.execute(txn, txn.gas_limit - static_cast<uint64_t>(g0));