correct calculation of LOG cost

libevmjit/Compiler.cpp

@@ -805,6 +805,9 @@ void Compiler::compileBasicBlock(BasicBlock& _basicBlock, bytes const& _bytecode
 			auto numBytes = stack.pop();
 			_memory.require(beginIdx, numBytes);
 
+			// This will commit the current cost block
+			_gasMeter.countLogData(numBytes);
+
 			std::array<llvm::Value*,4> topics;
 			auto numTopics = static_cast<size_t>(inst) - static_cast<size_t>(Instruction::LOG0);
 			for (size_t i = 0; i < numTopics; ++i)

libevmjit/GasMeter.cpp

@@ -47,6 +47,16 @@ uint64_t getStepCost(Instruction inst) // TODO: Add this function to FeeSructure
 	case Instruction::CREATE:
 		return static_cast<uint64_t>(c_createGas);
 
+	case Instruction::LOG0:
+	case Instruction::LOG1:
+	case Instruction::LOG2:
+	case Instruction::LOG3:
+	case Instruction::LOG4:
+	{
+		auto numTopics = static_cast<uint64_t>(inst) - static_cast<uint64_t>(Instruction::LOG0);
+		return static_cast<uint64_t>(c_logGas) + numTopics * static_cast<uint64_t>(c_logTopicGas);
+	}
+
 	default: // Assumes instruction code is valid
 		return static_cast<uint64_t>(c_stepGas);
 	}
@@ -138,6 +148,14 @@ void GasMeter::countSStore(Ext& _ext, llvm::Value* _index, llvm::Value* _newValu
 	createCall(m_gasCheckFunc, cost);
 }
 
+void GasMeter::countLogData(llvm::Value* _dataLength)
+{
+	assert(m_checkCall);
+	assert(m_blockCost > 0); // LOGn instruction is already counted
+	auto cost = m_builder.CreateMul(_dataLength, Constant::get(c_logDataGas), "logdata_cost");
+	commitCostBlock(cost);
+}
+
 void GasMeter::giveBack(llvm::Value* _gas)
 {
 	m_runtimeManager.setGas(m_builder.CreateAdd(m_runtimeManager.getGas(), _gas));

libevmjit/GasMeter.h

@@ -24,6 +24,9 @@ public:
 	/// Calculate & count gas cost for SSTORE instruction
 	void countSStore(class Ext& _ext, llvm::Value* _index, llvm::Value* _newValue);
 
+	/// Count gas cost of LOG data
+	void countLogData(llvm::Value* _dataLength);
+
 	/// Finalize cost-block by checking gas needed for the block before the block
 	/// @param _additionalCost adds additional cost to cost-block before commit
 	void commitCostBlock(llvm::Value* _additionalCost = nullptr);