Count gas using int64

libevmjit/BasicBlock.cpp

@@ -44,6 +44,7 @@ BasicBlock::LocalStack::LocalStack(BasicBlock& _owner) :
 
 void BasicBlock::LocalStack::push(llvm::Value* _value)
 {
+	assert(_value->getType() == Type::Word);
 	m_bblock.m_currentStack.push_back(_value);
 	m_bblock.m_tosOffset += 1;
 }

libevmjit/Compiler.cpp

@@ -630,7 +630,7 @@ void Compiler::compileBasicBlock(BasicBlock& _basicBlock, RuntimeManager& _runti
 		case Instruction::GAS:
 		{
 			_gasMeter.commitCostBlock();
-			stack.push(_runtimeManager.getGas());
+			stack.push(m_builder.CreateZExt(_runtimeManager.getGas(), Type::Word));
 			break;
 		}
 
@@ -770,6 +770,7 @@ void Compiler::compileBasicBlock(BasicBlock& _basicBlock, RuntimeManager& _runti
 				receiveAddress = _runtimeManager.get(RuntimeData::Address);
 
 			_gasMeter.count(gas);
+			// TODO: pass gas to call as int64
 			auto ret = _ext.call(gas, receiveAddress, value, inOff, inSize, outOff, outSize, codeAddress);
 			_gasMeter.giveBack(gas);
 			stack.push(ret);

libevmjit/Ext.cpp

@@ -128,12 +128,14 @@ llvm::Value* Ext::blockhash(llvm::Value* _number)
 
 llvm::Value* Ext::create(llvm::Value*& _gas, llvm::Value* _endowment, llvm::Value* _initOff, llvm::Value* _initSize)
 {
-	auto gas = byPtr(_gas);
+	auto gas256 = m_builder.CreateZExt(_gas, Type::Word, "gas256");
+	auto gas = byPtr(gas256);
 	auto ret = getArgAlloca();
 	auto begin = m_memoryMan.getBytePtr(_initOff);
 	auto size = m_builder.CreateTrunc(_initSize, Type::Size, "size");
 	createCall(EnvFunc::create, {getRuntimeManager().getEnvPtr(), gas, byPtr(_endowment), begin, size, ret});
-	_gas = m_builder.CreateLoad(gas); // Return gas
+	gas256 = m_builder.CreateLoad(gas); // Return gas
+	_gas = m_builder.CreateTrunc(gas256, Type::Gas);
 	llvm::Value* address = m_builder.CreateLoad(ret);
 	address = Endianness::toNative(m_builder, address);
 	return address;

libevmjit/GasMeter.cpp

@@ -19,29 +19,29 @@ namespace jit
 namespace // Helper functions
 {
 
-uint64_t const c_stepGas = 1;
-uint64_t const c_balanceGas = 20;
-uint64_t const c_sha3Gas = 10;
-uint64_t const c_sha3WordGas = 10;
-uint64_t const c_sloadGas = 20;
-uint64_t const c_sstoreSetGas = 300;
-uint64_t const c_sstoreResetGas = 100;
-uint64_t const c_sstoreRefundGas = 100;
-uint64_t const c_createGas = 100;
-uint64_t const c_createDataGas = 5;
-uint64_t const c_callGas = 20;
-uint64_t const c_expGas = 1;
-uint64_t const c_expByteGas = 1;
-uint64_t const c_memoryGas = 1;
-uint64_t const c_txDataZeroGas = 1;
-uint64_t const c_txDataNonZeroGas = 5;
-uint64_t const c_txGas = 500;
-uint64_t const c_logGas = 32;
-uint64_t const c_logDataGas = 1;
-uint64_t const c_logTopicGas = 32;
-uint64_t const c_copyGas = 1;
-
-uint64_t getStepCost(Instruction inst)
+int64_t const c_stepGas = 1;
+int64_t const c_balanceGas = 20;
+int64_t const c_sha3Gas = 10;
+int64_t const c_sha3WordGas = 10;
+int64_t const c_sloadGas = 20;
+int64_t const c_sstoreSetGas = 300;
+int64_t const c_sstoreResetGas = 100;
+int64_t const c_sstoreRefundGas = 100;
+int64_t const c_createGas = 100;
+int64_t const c_createDataGas = 5;
+int64_t const c_callGas = 20;
+int64_t const c_expGas = 1;
+int64_t const c_expByteGas = 1;
+int64_t const c_memoryGas = 1;
+int64_t const c_txDataZeroGas = 1;
+int64_t const c_txDataNonZeroGas = 5;
+int64_t const c_txGas = 500;
+int64_t const c_logGas = 32;
+int64_t const c_logDataGas = 1;
+int64_t const c_logTopicGas = 32;
+int64_t const c_copyGas = 1;
+
+int64_t getStepCost(Instruction inst)
 {
 	switch (inst)
 	{
@@ -72,7 +72,7 @@ uint64_t getStepCost(Instruction inst)
 	case Instruction::LOG3:
 	case Instruction::LOG4:
 	{
-		auto numTopics = static_cast<uint64_t>(inst) - static_cast<uint64_t>(Instruction::LOG0);
+		auto numTopics = static_cast<int64_t>(inst) - static_cast<int64_t>(Instruction::LOG0);
 		return c_logGas + numTopics * c_logTopicGas;
 	}
 	}
@@ -86,7 +86,7 @@ GasMeter::GasMeter(llvm::IRBuilder<>& _builder, RuntimeManager& _runtimeManager)
 {
 	auto module = getModule();
 
-	llvm::Type* gasCheckArgs[] = {Type::RuntimePtr, Type::Word};
+	llvm::Type* gasCheckArgs[] = {Type::RuntimePtr, Type::Gas};
 	m_gasCheckFunc = llvm::Function::Create(llvm::FunctionType::get(Type::Void, gasCheckArgs, false), llvm::Function::PrivateLinkage, "gas.check", module);
 	InsertPointGuard guard(m_builder);
 
@@ -94,15 +94,15 @@ GasMeter::GasMeter(llvm::IRBuilder<>& _builder, RuntimeManager& _runtimeManager)
 	auto outOfGasBB = llvm::BasicBlock::Create(_builder.getContext(), "OutOfGas", m_gasCheckFunc);
 	auto updateBB = llvm::BasicBlock::Create(_builder.getContext(), "Update", m_gasCheckFunc);
 
-	auto arg = m_gasCheckFunc->arg_begin();
-	arg->setName("rt");
-	++arg;
-	arg->setName("cost");
-	auto cost = arg;
+	auto rt = &m_gasCheckFunc->getArgumentList().front();
+	rt->setName("rt");
+	auto cost = rt->getNextNode();
+	cost->setName("cost");
 
 	m_builder.SetInsertPoint(checkBB);
 	auto gas = m_runtimeManager.getGas();
-	auto isOutOfGas = m_builder.CreateICmpUGT(cost, gas, "isOutOfGas");
+	gas = m_builder.CreateNSWSub(gas, cost, "gasUpdated");
+	auto isOutOfGas = m_builder.CreateICmpSLT(gas, m_builder.getInt64(0), "isOutOfGas"); // gas < 0, with gas == 0 we can still do 0 cost instructions
 	m_builder.CreateCondBr(isOutOfGas, outOfGasBB, updateBB);
 
 	m_builder.SetInsertPoint(outOfGasBB);
@@ -110,7 +110,6 @@ GasMeter::GasMeter(llvm::IRBuilder<>& _builder, RuntimeManager& _runtimeManager)
 	m_builder.CreateUnreachable();
 
 	m_builder.SetInsertPoint(updateBB);
-	gas = m_builder.CreateSub(gas, cost);
 	m_runtimeManager.setGas(gas);
 	m_builder.CreateRetVoid();
 }
@@ -120,7 +119,7 @@ void GasMeter::count(Instruction _inst)
 	if (!m_checkCall)
 	{
 		// Create gas check call with mocked block cost at begining of current cost-block
-		m_checkCall = createCall(m_gasCheckFunc, {m_runtimeManager.getRuntimePtr(), llvm::UndefValue::get(Type::Word)});
+		m_checkCall = createCall(m_gasCheckFunc, {m_runtimeManager.getRuntimePtr(), llvm::UndefValue::get(Type::Gas)});
 	}
 
 	m_blockCost += getStepCost(_inst);
@@ -128,6 +127,15 @@ void GasMeter::count(Instruction _inst)
 
 void GasMeter::count(llvm::Value* _cost)
 {
+	if (_cost->getType() == Type::Word)
+	{
+		auto gasMax256 = m_builder.CreateZExt(Constant::gasMax, Type::Word);
+		auto tooHigh = m_builder.CreateICmpUGT(_cost, gasMax256, "costTooHigh");
+		auto cost64 = m_builder.CreateTrunc(_cost, Type::Gas);
+		_cost = m_builder.CreateSelect(tooHigh, Constant::gasMax, cost64, "cost");
+	}
+
+	assert(_cost->getType() == Type::Gas);
 	createCall(m_gasCheckFunc, {m_runtimeManager.getRuntimePtr(), _cost});
 }
 
@@ -137,12 +145,13 @@ void GasMeter::countExp(llvm::Value* _exponent)
 	// lz - leading zeros
 	// cost = ((256 - lz) + 7) / 8
 
-	// OPT: All calculations can be done on 32/64 bits
+	// OPT: Can gas update be done in exp algorithm?
 
 	auto ctlz = llvm::Intrinsic::getDeclaration(getModule(), llvm::Intrinsic::ctlz, Type::Word);
-	auto lz = m_builder.CreateCall2(ctlz, _exponent, m_builder.getInt1(false));
-	auto sigBits = m_builder.CreateSub(Constant::get(256), lz);
-	auto sigBytes = m_builder.CreateUDiv(m_builder.CreateAdd(sigBits, Constant::get(7)), Constant::get(8));
+	auto lz256 = m_builder.CreateCall2(ctlz, _exponent, m_builder.getInt1(false));
+	auto lz = m_builder.CreateTrunc(lz256, Type::Gas, "lz");
+	auto sigBits = m_builder.CreateSub(m_builder.getInt64(256), lz, "sigBits");
+	auto sigBytes = m_builder.CreateUDiv(m_builder.CreateAdd(sigBits, m_builder.getInt64(7)), m_builder.getInt64(8));
 	count(sigBytes);
 }
 
@@ -155,8 +164,8 @@ void GasMeter::countSStore(Ext& _ext, llvm::Value* _index, llvm::Value* _newValu
 	auto newValueIsntZero = m_builder.CreateICmpNE(_newValue, Constant::get(0), "newValueIsntZero");
 	auto isInsert = m_builder.CreateAnd(oldValueIsZero, newValueIsntZero, "isInsert");
 	auto isDelete = m_builder.CreateAnd(oldValueIsntZero, newValueIsZero, "isDelete");
-	auto cost = m_builder.CreateSelect(isInsert, Constant::get(c_sstoreSetGas), Constant::get(c_sstoreResetGas), "cost");
-	cost = m_builder.CreateSelect(isDelete, Constant::get(0), cost, "cost");
+	auto cost = m_builder.CreateSelect(isInsert, m_builder.getInt64(c_sstoreSetGas), m_builder.getInt64(c_sstoreResetGas), "cost");
+	cost = m_builder.CreateSelect(isDelete, m_builder.getInt64(0), cost, "cost");
 	count(cost);
 }
 
@@ -179,13 +188,13 @@ void GasMeter::countSha3Data(llvm::Value* _dataLength)
 	auto dataLength64 = getBuilder().CreateTrunc(_dataLength, Type::lowPrecision);
 	auto words64 = m_builder.CreateUDiv(m_builder.CreateAdd(dataLength64, getBuilder().getInt64(31)), getBuilder().getInt64(32));
 	auto cost64 = m_builder.CreateNUWMul(getBuilder().getInt64(c_sha3WordGas), words64);
-	auto cost = getBuilder().CreateZExt(cost64, Type::Word);
-	count(cost);
+	count(cost64);
 }
 
 void GasMeter::giveBack(llvm::Value* _gas)
 {
-	m_runtimeManager.setGas(m_builder.CreateAdd(m_runtimeManager.getGas(), _gas));
+	assert(_gas->getType() == Type::Word);
+	m_runtimeManager.setGas(m_builder.CreateAdd(m_runtimeManager.getGas(), m_builder.CreateTrunc(_gas, Type::Gas)));
 }
 
 void GasMeter::commitCostBlock()
@@ -200,7 +209,7 @@ void GasMeter::commitCostBlock()
 			return;
 		}
 
-		m_checkCall->setArgOperand(1, Constant::get(m_blockCost)); // Update block cost in gas check call
+		m_checkCall->setArgOperand(1, m_builder.getInt64(m_blockCost)); // Update block cost in gas check call
 		m_checkCall = nullptr; // End cost-block
 		m_blockCost = 0;
 	}
@@ -209,14 +218,8 @@ void GasMeter::commitCostBlock()
 
 void GasMeter::countMemory(llvm::Value* _additionalMemoryInWords)
 {
-	assert(_additionalMemoryInWords->getType() == Type::Word);
 	static_assert(c_memoryGas == 1, "Memory gas cost has changed. Update GasMeter.");
-	auto gasMax256 = m_builder.CreateZExt(Constant::gasMax, Type::Word);
-	auto tooHigh = m_builder.CreateICmpUGT(_additionalMemoryInWords, gasMax256, "tooHigh");
-	auto additionalMemoryInWords64 = m_builder.CreateTrunc(_additionalMemoryInWords, Type::Gas);
-	additionalMemoryInWords64 = m_builder.CreateSelect(tooHigh, Constant::gasMax, additionalMemoryInWords64, "additionalMemoryInWords");
-	auto additionalMemoryInWords256 = m_builder.CreateZExt(additionalMemoryInWords64, Type::Word);
-	count(additionalMemoryInWords256);
+	count(_additionalMemoryInWords);
 }
 
 void GasMeter::countCopy(llvm::Value* _copyWords)

libevmjit/GasMeter.h

@@ -50,7 +50,7 @@ public:
 private:
 	/// Cumulative gas cost of a block of instructions
 	/// @TODO Handle overflow
-	uint64_t m_blockCost = 0;
+	int64_t m_blockCost = 0;
 
 	llvm::CallInst* m_checkCall = nullptr;
 	llvm::Function* m_gasCheckFunc = nullptr;

libevmjit/RuntimeManager.cpp

@@ -216,15 +216,15 @@ llvm::Value* RuntimeManager::getJmpBuf()
 
 llvm::Value* RuntimeManager::getGas()
 {
-	auto value = get(RuntimeData::Gas);
-	assert(value->getType() == Type::Size);
-	return getBuilder().CreateZExt(value, Type::Word);
+	auto gas = get(RuntimeData::Gas);
+	assert(gas->getType() == Type::Gas);
+	return gas;
 }
 
 void RuntimeManager::setGas(llvm::Value* _gas)
 {
-	auto newGas = getBuilder().CreateTrunc(_gas, Type::Size);
-	set(RuntimeData::Gas, newGas);
+	assert(_gas->getType() == Type::Gas);
+	set(RuntimeData::Gas, _gas);
 }
 
 }