Merge pull request #791 from imapp-pl/pr/evmjit_fixes

EVM JIT fixes

evmjit/libevmjit/Arith256.cpp

@@ -178,7 +178,10 @@ extern "C"
 		auto arg1 = llvm2eth(*_arg1);
 		auto arg2 = llvm2eth(*_arg2);
 		auto arg3 = llvm2eth(*_arg3);
-		*o_result = eth2llvm(u256((bigint(arg1) * bigint(arg2)) % arg3));
+		if (arg3 != 0)
+			*o_result = eth2llvm(u256((bigint(arg1) * bigint(arg2)) % arg3));
+		else
+			*o_result = {};
 	}
 
 	EXPORT void arith_addmod(i256* _arg1, i256* _arg2, i256* _arg3, i256* o_result)
@@ -186,7 +189,10 @@ extern "C"
 		auto arg1 = llvm2eth(*_arg1);
 		auto arg2 = llvm2eth(*_arg2);
 		auto arg3 = llvm2eth(*_arg3);
-		*o_result = eth2llvm(u256((bigint(arg1) + bigint(arg2)) % arg3));
+		if (arg3 != 0)
+			*o_result = eth2llvm(u256((bigint(arg1) + bigint(arg2)) % arg3));
+		else
+			*o_result = {};
 	}
 
 }

evmjit/libevmjit/Cache.cpp

@@ -45,8 +45,7 @@ std::unique_ptr<llvm::Module> Cache::getObject(std::string const& id)
 	{
 		auto module = std::unique_ptr<llvm::Module>(new llvm::Module(id, llvm::getGlobalContext()));
 		auto mainFuncType = llvm::FunctionType::get(llvm::IntegerType::get(llvm::getGlobalContext(), 32), {}, false);
-		auto func = llvm::Function::Create(mainFuncType, llvm::Function::ExternalLinkage, id, module.get());
-		(void)func;
+		llvm::Function::Create(mainFuncType, llvm::Function::ExternalLinkage, id, module.get());
 	}
 	return nullptr;
 }
@@ -69,9 +68,8 @@ void ObjectCache::notifyObjectCompiled(llvm::Module const* _module, llvm::Memory
 	cacheFile << _object->getBuffer();
 }
 
-llvm::MemoryBuffer* ObjectCache::getObject(llvm::Module const* _module)
+llvm::MemoryBuffer* ObjectCache::getObject(llvm::Module const*)
 {
-	(void)_module;
 	auto o = lastObject;
 	lastObject = nullptr;
 	return o;

evmjit/libevmjit/Ext.cpp

@@ -22,11 +22,9 @@ namespace jit
 
 Ext::Ext(RuntimeManager& _runtimeManager, Memory& _memoryMan):
 	RuntimeHelper(_runtimeManager),
-	m_memoryMan(_memoryMan)
-	// TODO: fix: either initialise properly or don't specify in constructor.
-	/*,
-	m_funcs{},
-	m_argAllocas{}*/
+	m_memoryMan(_memoryMan),
+	m_funcs({}),  // The only std::array initialization that works in both Visual Studio & GCC
+	m_argAllocas({})
 {
 	m_size = m_builder.CreateAlloca(Type::Size, nullptr, "env.size");
 }

evmjit/libevmjit/GasMeter.cpp

@@ -173,10 +173,12 @@ void GasMeter::countSha3Data(llvm::Value* _dataLength)
 	assert(m_blockCost > 0); // SHA3 instruction is already counted
 
 	// TODO: This round ups to 32 happens in many places
-	// FIXME: Overflow possible but Memory::require() also called. Probably 64-bit arith can be used.
+	// FIXME: 64-bit arith used, but not verified
 	static_assert(c_sha3WordGas != 1, "SHA3 data cost has changed. Update GasMeter");
-	auto words = m_builder.CreateUDiv(m_builder.CreateAdd(_dataLength, Constant::get(31)), Constant::get(32));
-	auto cost = m_builder.CreateNUWMul(Constant::get(c_sha3WordGas), words);
+	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);
 }
 

evmjit/libevmjit/Runtime.cpp

@@ -24,8 +24,10 @@ bytes Runtime::getReturnData() const	// FIXME: Reconsider returning by copy
 	auto offset = static_cast<size_t>(llvm2eth(m_data.elems[RuntimeData::ReturnDataOffset]));
 	auto size = static_cast<size_t>(llvm2eth(m_data.elems[RuntimeData::ReturnDataSize]));
 
-	assert(offset + size <= m_memory.size());
-	// TODO: Handle invalid data access by returning empty ref
+	assert(offset + size <= m_memory.size() || size == 0);
+	if (offset + size > m_memory.size())
+		return {};
+
 	auto dataBeg = m_memory.begin() + offset;
 	return {dataBeg, dataBeg + size};
 }