Try to throw an OutOfGas exception when out of gas. The exception cannot be handled.

[#80660432]

evmcc/ExecutionEngine.cpp

@@ -13,6 +13,8 @@
 #include <llvm/Support/PrettyStackTrace.h>
 #include <llvm/Support/Host.h>
 
+#include <libevm/VM.h>
+
 #include "Runtime.h"
 #include "Memory.h"
 #include "Type.h"
@@ -87,7 +89,7 @@ int ExecutionEngine::run(std::unique_ptr<llvm::Module> _module)
 	ext->data = calldata;
 
 	// Init runtime
-	uint64_t gas = 1000000;
+	uint64_t gas = 100;
 	Runtime runtime(gas, std::move(ext));
 
 	auto entryFunc = module->getFunction("main");
@@ -97,9 +99,20 @@ int ExecutionEngine::run(std::unique_ptr<llvm::Module> _module)
 		exit(1);
 	}
 
-	auto result = exec->runFunction(entryFunc, {});
+
+	ReturnCode returnCode;
+	try
+	{
+		auto result = exec->runFunction(entryFunc, {});
+		returnCode = static_cast<ReturnCode>(result.IntVal.getZExtValue());
+	}
+	catch (const dev::eth::OutOfGas&)
+	{
+		returnCode = ReturnCode::OutOfGas;
+	}
+
 	gas = static_cast<decltype(gas)>(Runtime::getGas());
-	auto returnCode = static_cast<ReturnCode>(result.IntVal.getZExtValue());
+	
 	if (returnCode == ReturnCode::Return)
 	{
 		auto&& returnData = Memory::getReturnData(); // TODO: It might be better to place is in Runtime interface
@@ -108,10 +121,8 @@ int ExecutionEngine::run(std::unique_ptr<llvm::Module> _module)
 		for (auto it = returnData.begin(), end = returnData.end(); it != end; ++it)
 			std::cout << std::hex << std::setw(2) << std::setfill('0') << (int)*it << " ";
 		std::cout << "]\n";
-
-		return 10;
 	}	
-	return 0;
+	return static_cast<int>(returnCode);
 }
 
 }

evmcc/GasMeter.cpp

@@ -83,11 +83,27 @@ GasMeter::GasMeter(llvm::IRBuilder<>& _builder, llvm::Module* _module):
 	m_gas = new llvm::GlobalVariable(*_module, Type::i256, false, llvm::GlobalVariable::ExternalLinkage, nullptr, "gas");
 	m_gas->setUnnamedAddr(true); // Address is not important
 
+	m_rtExit = llvm::Function::Create(llvm::FunctionType::get(Type::Void, Type::MainReturn, false), llvm::Function::ExternalLinkage, "rt_exit", _module);
+
 	m_gasCheckFunc = llvm::Function::Create(llvm::FunctionType::get(Type::Void, Type::i256, false), llvm::Function::PrivateLinkage, "gas.check", _module);
 	InsertPointGuard guard(m_builder); 
-	m_builder.SetInsertPoint(llvm::BasicBlock::Create(_builder.getContext(), {}, m_gasCheckFunc));
+
+	auto checkBB = llvm::BasicBlock::Create(_builder.getContext(), "check", m_gasCheckFunc);
+	auto outOfGasBB = llvm::BasicBlock::Create(_builder.getContext(), "outOfGas", m_gasCheckFunc);
+	auto updateBB = llvm::BasicBlock::Create(_builder.getContext(), "update", m_gasCheckFunc);
+
+	m_builder.SetInsertPoint(checkBB);
 	llvm::Value* cost = m_gasCheckFunc->arg_begin();
-	llvm::Value* gas = m_builder.CreateLoad(m_gas);
+	cost->setName("cost");
+	llvm::Value* gas = m_builder.CreateLoad(m_gas, "gas");
+	auto isOutOfGas = m_builder.CreateICmpUGT(cost, gas, "isOutOfGas");
+	m_builder.CreateCondBr(isOutOfGas, outOfGasBB, updateBB);
+
+	m_builder.SetInsertPoint(outOfGasBB);
+	m_builder.CreateCall(m_rtExit, Constant::get(ReturnCode::OutOfGas));
+	m_builder.CreateRetVoid();
+
+	m_builder.SetInsertPoint(updateBB);
 	gas = m_builder.CreateSub(gas, cost);
 	m_builder.CreateStore(gas, m_gas);
 	m_builder.CreateRetVoid();

evmcc/GasMeter.h

@@ -41,6 +41,7 @@ private:
 	llvm::IRBuilder<>& m_builder;
 	llvm::CallInst* m_checkCall = nullptr;
 	llvm::GlobalVariable* m_gas;
+	llvm::Function* m_rtExit;
 	llvm::Function* m_gasCheckFunc;
 };
 

evmcc/Runtime.cpp

@@ -1,12 +1,27 @@
 
 #include "Runtime.h"
 
+#include <libevm/VM.h>
+
+#include "Type.h"
+
 namespace evmcc
 {
 
 static Runtime* g_runtime;
 
-extern "C" { EXPORT i256 gas; }
+extern "C"
+{
+EXPORT i256 gas;
+
+EXPORT void rt_exit(int32_t _returnCode)
+{
+	auto returnCode = static_cast<ReturnCode>(_returnCode);
+	if (returnCode == ReturnCode::OutOfGas)
+		BOOST_THROW_EXCEPTION(dev::eth::OutOfGas());
+}
+
+}
 
 Runtime::Runtime(dev::u256 _gas, std::unique_ptr<dev::eth::ExtVMFace> _ext):
 	m_ext(std::move(_ext))

evmcc/Type.h

@@ -34,6 +34,7 @@ enum class ReturnCode
 	Suicide = 2,
 
 	BadJumpDestination = 101,
+	OutOfGas = 102,
 };
 
 struct Constant