Pop entry state of basic block from external stack, push exit state to external stack.

[Delivers #80113346]

evmcc/Compiler.cpp

@@ -188,12 +188,12 @@ std::unique_ptr<llvm::Module> Compiler::compile(const dev::bytes& bytecode)
 	createBasicBlocks(bytecode);
 
 	// Init runtime structures.
-	auto globalStack = Stack(builder, module.get());
+	auto extStack = Stack(builder, module.get());
 	auto memory = Memory(builder, module.get());
 	auto ext = Ext(builder, module.get());
 
 	BasicBlock* currentBlock = entryBlock;
-	BBStack stack; // Stack for current block
+	BBStack stack(extStack); // Stack for current block
 
 	for (auto pc = bytecode.cbegin(); pc != bytecode.cend(); ++pc)
 	{
@@ -212,7 +212,7 @@ std::unique_ptr<llvm::Module> Compiler::compile(const dev::bytes& bytecode)
 			mainFunc->getBasicBlockList().push_back(nextBlock);
 			builder.SetInsertPoint(nextBlock);
 			currentBlock = nextBlock;
-			stack = BBStack();	// Reset stack
+			assert(stack.empty()); // Stack should be empty
 		}
 
 		assert(currentBlock != nullptr);
@@ -579,6 +579,7 @@ std::unique_ptr<llvm::Module> Compiler::compile(const dev::bytes& bytecode)
 			// The target address is computed at compile time,
 			// just pop it without looking...
 			stack.pop();
+			stack.reset();
 
 			auto targetBlock = jumpTargets[currentPC];
 			builder.CreateBr(targetBlock);
@@ -598,6 +599,7 @@ std::unique_ptr<llvm::Module> Compiler::compile(const dev::bytes& bytecode)
 			auto top = stack.pop();
 			auto zero = ConstantInt::get(Types.word256, 0);
 			auto cond = builder.CreateICmpNE(top, zero, "nonzero");
+			stack.reset();
 			auto targetBlock = jumpTargets[currentPC];
 			auto followBlock = basicBlocks[currentPC + 1];
 			builder.CreateCondBr(cond, targetBlock, followBlock);
@@ -764,6 +766,7 @@ std::unique_ptr<llvm::Module> Compiler::compile(const dev::bytes& bytecode)
 			ret = builder.CreateOr(ret, size);
 
 			builder.CreateRet(ret);
+			stack.clear();
 			currentBlock = nullptr;
 			break;
 		}
@@ -777,6 +780,7 @@ std::unique_ptr<llvm::Module> Compiler::compile(const dev::bytes& bytecode)
 		case Instruction::STOP:
 		{
 			builder.CreateRet(builder.getInt64(0));
+			stack.clear();
 			currentBlock = nullptr;
 			break;
 		}

evmcc/ExecutionEngine.cpp

@@ -103,7 +103,7 @@ int ExecutionEngine::run(std::unique_ptr<llvm::Module> _module)
 		std::cout << "RETURN [ ";
 		for (dev::bytes::const_iterator it = Runtime::getMemory().cbegin() + index, end = it + size; it != end; ++it)
 			std::cout << std::hex << std::setw(2) << std::setfill('0') << (int)*it << " ";
-		std::cout << "]";
+		std::cout << "]\n";
 
 		return 10;
 	}	

evmcc/Stack.cpp

@@ -20,6 +20,10 @@
 namespace evmcc
 {
 
+BBStack::BBStack(Stack& _extStack)
+	: m_extStack(_extStack)
+{}
+
 void BBStack::push(llvm::Value* _value)
 {
 	m_state.push_back(_value);
@@ -27,11 +31,31 @@ void BBStack::push(llvm::Value* _value)
 
 llvm::Value* BBStack::pop()
 {
+	if (m_state.empty())
+		return m_extStack.pop();
+
 	auto top = m_state.back();
 	m_state.pop_back();
 	return top;
 }
 
+void BBStack::reset()
+{
+	for (auto&& value : m_state)
+		m_extStack.push(value);
+	m_state.clear();
+}
+
+void BBStack::clear()
+{
+	m_state.clear();
+}
+
+bool BBStack::empty() const
+{
+	return m_state.empty();
+}
+
 void BBStack::dup(size_t _index)
 {
 	auto value = *(m_state.rbegin() + _index);

evmcc/Stack.h

@@ -36,15 +36,31 @@ private:
 class BBStack
 {
 public:
-	//BBStack(llvm::IRBuilder<>& _builder, llvm::Module* _module);
+	BBStack(Stack& _extStack);
 
 	void push(llvm::Value* _value);
 	llvm::Value* pop();
 	void dup(size_t _index);
 	void swap(size_t _index);
 
+	/**
+	 Resets stack on basic block change.
+	 Values left on local stack are pushed on external stack.
+	 Local stack is empty after this operation and compilation of new basic block can be started.
+	 */
+	void reset();
+
+	/**
+	 Dumps values on stack.
+	 */
+	void clear();
+
+	/// Debug only
+	bool empty() const;
+
 private:
 	std::vector<llvm::Value*> m_state;	///< Basic black state vector - current values and their positions
+	Stack& m_extStack;                  ///< External (global) stack
 };
 
 

evmcc/bytecode/stackjump.evm

@@ -0,0 +1 @@
+600460066009601358600a036000545b6000f260005401600958