Allocate memory and count gas for RETURN instruction

[#79942174]

evmcc/ExecutionEngine.cpp

@@ -102,7 +102,7 @@ int ExecutionEngine::run(std::unique_ptr<llvm::Module> _module)
 	auto returnCode = static_cast<ReturnCode>(result.IntVal.getZExtValue());
 	if (returnCode == ReturnCode::Return)
 	{
-		auto&& returnData = Memory::getReturnData();
+		auto&& returnData = Memory::getReturnData(); // TODO: It might be better to place is in Runtime interface
 
 		std::cout << "RETURN [ ";
 		for (auto it = returnData.begin(), end = returnData.end(); it != end; ++it)

evmcc/Memory.cpp

@@ -133,6 +133,9 @@ llvm::Value* Memory::getSize()
 
 void Memory::registerReturnData(llvm::Value* _index, llvm::Value* _size)
 {
+	auto lastWord = m_builder.CreateAdd(_index, m_builder.CreateSub(_size, Constant::get(32)), "lastWord");
+	loadWord(lastWord); // Make sure that memory is allocated and count gas
+
 	m_builder.CreateStore(_index, m_returnDataOffset);
 	m_builder.CreateStore(_size, m_returnDataSize);
 }

evmcc/Type.cpp

@@ -25,6 +25,11 @@ void Type::init(llvm::LLVMContext& _context)
 	MainReturn = llvm::Type::getInt32Ty(_context);
 }
 
+llvm::Constant* Constant::get(uint64_t _n)
+{
+	return llvm::ConstantInt::get(Type::i256, _n);
+}
+
 llvm::Constant* Constant::get(ReturnCode _returnCode)
 {
 	return llvm::ConstantInt::get(Type::MainReturn, static_cast<uint64_t>(_returnCode));

evmcc/Type.h

@@ -38,6 +38,9 @@ enum class ReturnCode
 
 struct Constant
 {
+	/// Returns word-size constant
+	static llvm::Constant* get(uint64_t _n);
+
 	static llvm::Constant* get(ReturnCode _returnCode);
 };
 

evmcc/bytecode/return2.evm

@@ -0,0 +1 @@
+6001620f4240f2

evmcc/lll/return2.lll

@@ -0,0 +1,6 @@
+
+(asm 
+1
+1000000
+RETURN	;; return 1 byte from index 1M
+)