6 files changed, 61 insertions, 18 deletions
diff --git a/libsolidity/codegen/ArrayUtils.cpp b/libsolidity/codegen/ArrayUtils.cpp
index 4d100d1d..bdd29abd 100644
--- a/libsolidity/codegen/ArrayUtils.cpp
+++ b/libsolidity/codegen/ArrayUtils.cpp
@@ -901,7 +901,7 @@ void ArrayUtils::accessIndex(ArrayType const& _arrayType, bool _doBoundsCheck) c
 		// check out-of-bounds access
 		m_context << Instruction::DUP2 << Instruction::LT << Instruction::ISZERO;
 		// out-of-bounds access throws exception
-		m_context.appendConditionalJumpTo(m_context.errorTag());
+		m_context.appendConditionalInvalid();
 	}
 	if (location == DataLocation::CallData && _arrayType.isDynamicallySized())
 		// remove length if present
diff --git a/libsolidity/codegen/CompilerContext.cpp b/libsolidity/codegen/CompilerContext.cpp
index e26f96e8..a8316109 100644
--- a/libsolidity/codegen/CompilerContext.cpp
+++ b/libsolidity/codegen/CompilerContext.cpp
@@ -70,19 +70,30 @@ void CompilerContext::callLowLevelFunction(
 	eth::AssemblyItem retTag = pushNewTag();
 	CompilerUtils(*this).moveIntoStack(_inArgs);
 
+	*this << lowLevelFunctionTag(_name, _inArgs, _outArgs, _generator);
+
+	appendJump(eth::AssemblyItem::JumpType::IntoFunction);
+	adjustStackOffset(int(_outArgs) - 1 - _inArgs);
+	*this << retTag.tag();
+}
+
+eth::AssemblyItem CompilerContext::lowLevelFunctionTag(
+	string const& _name,
+	unsigned _inArgs,
+	unsigned _outArgs,
+	function<void(CompilerContext&)> const& _generator
+)
+{
 	auto it = m_lowLevelFunctions.find(_name);
 	if (it == m_lowLevelFunctions.end())
 	{
 		eth::AssemblyItem tag = newTag().pushTag();
 		m_lowLevelFunctions.insert(make_pair(_name, tag));
 		m_lowLevelFunctionGenerationQueue.push(make_tuple(_name, _inArgs, _outArgs, _generator));
-		*this << tag;
+		return tag;
 	}
 	else
-		*this << it->second;
-	appendJump(eth::AssemblyItem::JumpType::IntoFunction);
-	adjustStackOffset(int(_outArgs) - 1 - _inArgs);
-	*this << retTag.tag();
+		return it->second;
 }
 
 void CompilerContext::appendMissingLowLevelFunctions()
@@ -215,6 +226,20 @@ CompilerContext& CompilerContext::appendJump(eth::AssemblyItem::JumpType _jumpTy
 	return *this << item;
 }
 
+CompilerContext& CompilerContext::appendInvalid()
+{
+	return *this << Instruction::INVALID;
+}
+
+CompilerContext& CompilerContext::appendConditionalInvalid()
+{
+	*this << Instruction::ISZERO;
+	eth::AssemblyItem afterTag = appendConditionalJump();
+	*this << Instruction::INVALID;
+	*this << afterTag;
+	return *this;
+}
+
 void CompilerContext::resetVisitedNodes(ASTNode const* _node)
 {
 	stack<ASTNode const*> newStack;
diff --git a/libsolidity/codegen/CompilerContext.h b/libsolidity/codegen/CompilerContext.h
index f024b010..c37142c9 100644
--- a/libsolidity/codegen/CompilerContext.h
+++ b/libsolidity/codegen/CompilerContext.h
@@ -104,6 +104,16 @@ public:
 		unsigned _outArgs,
 		std::function<void(CompilerContext&)> const& _generator
 	);
+	/// Returns the tag of the named low-level function and inserts the generator into the
+	/// list of low-level-functions to be generated, unless it already exists.
+	/// Note that the generator should not assume that objects are still alive when it is called,
+	/// unless they are guaranteed to be alive for the whole run of the compiler (AST nodes, for example).
+	eth::AssemblyItem lowLevelFunctionTag(
+		std::string const& _name,
+		unsigned _inArgs,
+		unsigned _outArgs,
+		std::function<void(CompilerContext&)> const& _generator
+	);
 	/// Generates the code for missing low-level functions, i.e. calls the generators passed above.
 	void appendMissingLowLevelFunctions();
 
@@ -127,6 +137,10 @@ public:
 	eth::AssemblyItem appendJumpToNew() { return m_asm->appendJump().tag(); }
 	/// Appends a JUMP to a tag already on the stack
 	CompilerContext&  appendJump(eth::AssemblyItem::JumpType _jumpType = eth::AssemblyItem::JumpType::Ordinary);
+	/// Appends an INVALID instruction
+	CompilerContext&  appendInvalid();
+	/// Appends a conditional INVALID instruction
+	CompilerContext&  appendConditionalInvalid();
 	/// Returns an "ErrorTag"
 	eth::AssemblyItem errorTag() { return m_asm->errorTag(); }
 	/// Appends a JUMP to a specific tag
diff --git a/libsolidity/codegen/CompilerUtils.cpp b/libsolidity/codegen/CompilerUtils.cpp
index caf3b1ac..477f021a 100644
--- a/libsolidity/codegen/CompilerUtils.cpp
+++ b/libsolidity/codegen/CompilerUtils.cpp
@@ -468,7 +468,7 @@ void CompilerUtils::convertType(Type const& _typeOnStack, Type const& _targetTyp
 			EnumType const& enumType = dynamic_cast<decltype(enumType)>(_typeOnStack);
 			solAssert(enumType.numberOfMembers() > 0, "empty enum should have caused a parser error.");
 			m_context << u256(enumType.numberOfMembers() - 1) << Instruction::DUP2 << Instruction::GT;
-			m_context.appendConditionalJumpTo(m_context.errorTag());
+			m_context.appendConditionalInvalid();
 			enumOverflowCheckPending = false;
 		}
 		break;
@@ -497,7 +497,7 @@ void CompilerUtils::convertType(Type const& _typeOnStack, Type const& _targetTyp
 			EnumType const& enumType = dynamic_cast<decltype(enumType)>(_targetType);
 			solAssert(enumType.numberOfMembers() > 0, "empty enum should have caused a parser error.");
 			m_context << u256(enumType.numberOfMembers() - 1) << Instruction::DUP2 << Instruction::GT;
-			m_context.appendConditionalJumpTo(m_context.errorTag());
+			m_context.appendConditionalInvalid();
 			enumOverflowCheckPending = false;
 		}
 		else if (targetTypeCategory == Type::Category::FixedPoint)
@@ -807,7 +807,9 @@ void CompilerUtils::pushZeroValue(Type const& _type)
 	{
 		if (funType->location() == FunctionType::Location::Internal)
 		{
-			m_context << m_context.errorTag();
+			m_context << m_context.lowLevelFunctionTag("$invalidFunction", 0, 0, [](CompilerContext& _context) {
+				_context.appendInvalid();
+			});
 			return;
 		}
 	}
diff --git a/libsolidity/codegen/ContractCompiler.cpp b/libsolidity/codegen/ContractCompiler.cpp
index 9dc1fb37..4d33927d 100644
--- a/libsolidity/codegen/ContractCompiler.cpp
+++ b/libsolidity/codegen/ContractCompiler.cpp
@@ -106,7 +106,7 @@ void ContractCompiler::appendCallValueCheck()
 {
 	// Throw if function is not payable but call contained ether.
 	m_context << Instruction::CALLVALUE;
-	m_context.appendConditionalJumpTo(m_context.errorTag());
+	m_context.appendConditionalInvalid();
 }
 
 void ContractCompiler::appendInitAndConstructorCode(ContractDefinition const& _contract)
@@ -271,7 +271,7 @@ void ContractCompiler::appendFunctionSelector(ContractDefinition const& _contrac
 		appendReturnValuePacker(FunctionType(*fallback).returnParameterTypes(), _contract.isLibrary());
 	}
 	else
-		m_context.appendJumpTo(m_context.errorTag());
+		m_context.appendInvalid();
 
 	for (auto const& it: interfaceFunctions)
 	{
@@ -918,7 +918,9 @@ eth::AssemblyPointer ContractCompiler::cloneRuntime()
 	a << Instruction::DELEGATECALL;
 	//Propagate error condition (if DELEGATECALL pushes 0 on stack).
 	a << Instruction::ISZERO;
-	a.appendJumpI(a.errorTag());
+	a << Instruction::ISZERO;
+	eth::AssemblyItem afterTag = a.appendJumpI().tag();
+	a << Instruction::INVALID << afterTag;
 	//@todo adjust for larger return values, make this dynamic.
 	a << u256(0x20) << u256(0) << Instruction::RETURN;
 	return make_shared<eth::Assembly>(a);
diff --git a/libsolidity/codegen/ExpressionCompiler.cpp b/libsolidity/codegen/ExpressionCompiler.cpp
index bda4e04d..b66a3e12 100644
--- a/libsolidity/codegen/ExpressionCompiler.cpp
+++ b/libsolidity/codegen/ExpressionCompiler.cpp
@@ -585,7 +585,7 @@ bool ExpressionCompiler::visit(FunctionCall const& _functionCall)
 			m_context << Instruction::CREATE;
 			// Check if zero (out of stack or not enough balance).
 			m_context << Instruction::DUP1 << Instruction::ISZERO;
-			m_context.appendConditionalJumpTo(m_context.errorTag());
+			m_context.appendConditionalInvalid();
 			if (function.valueSet())
 				m_context << swapInstruction(1) << Instruction::POP;
 			break;
@@ -1234,7 +1234,7 @@ bool ExpressionCompiler::visit(IndexAccess const& _indexAccess)
 		m_context << u256(fixedBytesType.numBytes());
 		m_context << Instruction::DUP2 << Instruction::LT << Instruction::ISZERO;
 		// out-of-bounds access throws exception
-		m_context.appendConditionalJumpTo(m_context.errorTag());
+		m_context.appendConditionalInvalid();
 
 		m_context << Instruction::BYTE;
 		m_context << (u256(1) << (256 - 8)) << Instruction::MUL;
@@ -1416,7 +1416,7 @@ void ExpressionCompiler::appendArithmeticOperatorCode(Token::Value _operator, Ty
 	{
 		// Test for division by zero
 		m_context << Instruction::DUP2 << Instruction::ISZERO;
-		m_context.appendConditionalJumpTo(m_context.errorTag());
+		m_context.appendConditionalInvalid();
 
 		if (_operator == Token::Div)
 			m_context << (c_isSigned ? Instruction::SDIV : Instruction::DIV);
@@ -1477,7 +1477,7 @@ void ExpressionCompiler::appendShiftOperatorCode(Token::Value _operator, Type co
 	if (c_amountSigned)
 	{
 		m_context << u256(0) << Instruction::DUP3 << Instruction::SLT;
-		m_context.appendConditionalJumpTo(m_context.errorTag());
+		m_context.appendConditionalInvalid();
 	}
 
 	switch (_operator)
@@ -1663,7 +1663,7 @@ void ExpressionCompiler::appendExternalFunctionCall(
 	if (funKind == FunctionKind::External || funKind == FunctionKind::CallCode || funKind == FunctionKind::DelegateCall)
 	{
 		m_context << Instruction::DUP1 << Instruction::EXTCODESIZE << Instruction::ISZERO;
-		m_context.appendConditionalJumpTo(m_context.errorTag());
+		m_context.appendConditionalInvalid();
 		existenceChecked = true;
 	}
 
@@ -1699,7 +1699,7 @@ void ExpressionCompiler::appendExternalFunctionCall(
 	{
 		//Propagate error condition (if CALL pushes 0 on stack).
 		m_context << Instruction::ISZERO;
-		m_context.appendConditionalJumpTo(m_context.errorTag());
+		m_context.appendConditionalInvalid();
 	}
 
 	utils().popStackSlots(remainsSize);