Compiler EVM generation now takes into account for the new function hash

identifier

- Changed tests to comply with the new function hash identifier
- Changed the function index offset to 4, and made it a constant for
  easy adjustment in the future

Compiler.cpp

@@ -100,7 +100,7 @@ void Compiler::appendConstructorCall(FunctionDefinition const& _constructor)
 	{
 		m_context << u256(argumentSize);
 		m_context.appendProgramSize();
-		m_context << u256(1); // copy it to byte one as expected for ABI calls
+		m_context << u256(g_functionIdentifierOffset); // copy it to byte four as expected for ABI calls
 		m_context << eth::Instruction::CODECOPY;
 		appendCalldataUnpacker(_constructor, true);
 	}
@@ -125,12 +125,12 @@ void Compiler::appendFunctionSelector(ContractDefinition const& _contract)
 		BOOST_THROW_EXCEPTION(CompilerError() << errinfo_comment("More than 4294967295 public functions for contract."));
 
 	// retrieve the function signature hash from the calldata
-	m_context << u256(1) << u256(0) << u256(4294967296) * u256(4294967296) * u256(4294967296) * u256(4294967296) * u256(4294967296) * u256(4294967296) * u256(4294967296)// some constants
+	m_context << u256(1) << u256(0) << (u256(1) << 224) // some constants
 			  << eth::dupInstruction(2) << eth::Instruction::CALLDATALOAD
 			  << eth::Instruction::DIV;
 
 	// stack now is: 1 0 <funhash>
-	for (auto it = interfaceFunctions.begin(); it != interfaceFunctions.end(); ++it)
+	for (auto it = interfaceFunctions.cbegin(); it != interfaceFunctions.cend(); ++it)
 	{
 		callDataUnpackerEntryPoints.push_back(m_context.newTag());
 		m_context << eth::dupInstruction(1) << u256(FixedHash<4>::Arith(it->first)) << eth::Instruction::EQ;
@@ -139,7 +139,7 @@ void Compiler::appendFunctionSelector(ContractDefinition const& _contract)
 	m_context << eth::Instruction::STOP; // function not found
 
 	unsigned funid = 0;
-	for (auto it = interfaceFunctions.begin(); it != interfaceFunctions.end(); ++it, ++funid)
+	for (auto it = interfaceFunctions.cbegin(); it != interfaceFunctions.cend(); ++it, ++funid)
 	{
 		FunctionDefinition const& function = *it->second;
 		m_context << callDataUnpackerEntryPoints[funid];
@@ -154,7 +154,7 @@ void Compiler::appendFunctionSelector(ContractDefinition const& _contract)
 unsigned Compiler::appendCalldataUnpacker(FunctionDefinition const& _function, bool _fromMemory)
 {
 	// We do not check the calldata size, everything is zero-padded.
-	unsigned dataOffset = 1;
+	unsigned dataOffset = g_functionIdentifierOffset; // the 4 bytes of the function hash signature
 	//@todo this can be done more efficiently, saving some CALLDATALOAD calls
 	for (ASTPointer<VariableDeclaration> const& var: _function.getParameters())
 	{

CompilerUtils.h

@@ -30,6 +30,9 @@ namespace solidity {
 
 class Type; // forward
 
+/// The size in bytes of the function (hash) identifier
+static const unsigned int g_functionIdentifierOffset = 4;
+
 class CompilerUtils
 {
 public:

ExpressionCompiler.cpp

@@ -335,7 +335,7 @@ void ExpressionCompiler::endVisit(MemberAccess const& _memberAccess)
 	case Type::Category::CONTRACT:
 	{
 		ContractType const& type = dynamic_cast<ContractType const&>(*_memberAccess.getExpression().getType());
-		m_context << type.getFunctionIndex(member);
+		m_context << type.getFunctionIdentifier(member);
 		break;
 	}
 	case Type::Category::MAGIC:
@@ -590,7 +590,11 @@ void ExpressionCompiler::appendExternalFunctionCall(FunctionType const& _functio
 {
 	solAssert(_arguments.size() == _functionType.getParameterTypes().size(), "");
 
-	unsigned dataOffset = _options.bare ? 0 : 1; // reserve one byte for the function index
+	_options.obtainAddress();
+	if (!_options.bare)
+		CompilerUtils(m_context).storeInMemory(0, g_functionIdentifierOffset);
+
+	unsigned dataOffset = _options.bare ? 0 : g_functionIdentifierOffset; // reserve 4 bytes for the function's hash identifier
 	for (unsigned i = 0; i < _arguments.size(); ++i)
 	{
 		_arguments[i]->accept(*this);
@@ -617,12 +621,13 @@ void ExpressionCompiler::appendExternalFunctionCall(FunctionType const& _functio
 		_options.obtainValue();
 	else
 		m_context << u256(0);
-	_options.obtainAddress();
+	m_context << eth::dupInstruction(6); //copy contract address
-	if (!_options.bare)
+
-		m_context << u256(0) << eth::Instruction::MSTORE8;
 	m_context << u256(25) << eth::Instruction::GAS << eth::Instruction::SUB
 			  << eth::Instruction::CALL
-			  << eth::Instruction::POP; // @todo do not ignore failure indicator
+			  << eth::Instruction::POP // @todo do not ignore failure indicator
+			  << eth::Instruction::POP; // pop contract address
+
 	if (retSize > 0)
 	{
 		bool const leftAligned = firstType->getCategory() == Type::Category::STRING;

Types.cpp

@@ -323,16 +323,13 @@ shared_ptr<FunctionType const> const& ContractType::getConstructorType() const
 	return m_constructorType;
 }
 
-unsigned ContractType::getFunctionIndex(string const& _functionName) const
+u256 ContractType::getFunctionIdentifier(string const& _functionName) const
 {
-	unsigned index = 0;
 	auto interfaceFunctions = m_contract.getInterfaceFunctions();
 	for (auto it = interfaceFunctions.cbegin(); it != interfaceFunctions.cend(); ++it)
-	{
 		if (it->second->getName() == _functionName)
-			return index;
+			return FixedHash<4>::Arith(it->first);
-		++index;
+
-	}
 	BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Index of non-existing contract function requested."));
 }
 

Types.h

@@ -254,7 +254,7 @@ public:
 	/// is not used, as this type cannot be the type of a variable or expression.
 	std::shared_ptr<FunctionType const> const& getConstructorType() const;
 
-	unsigned getFunctionIndex(std::string const& _functionName) const;
+	u256 getFunctionIdentifier(std::string const& _functionName) const;
 
 private:
 	ContractDefinition const& m_contract;