Merge pull request #3503 from ethereum/develop

Merge develop into release for v0.4.20.

7 files changed, 131 insertions, 21 deletions

diff --git a/libsolidity/codegen/ABIFunctions.cpp b/libsolidity/codegen/ABIFunctions.cpp
index 6648be06..00f59065 100644
--- a/libsolidity/codegen/ABIFunctions.cpp
+++ b/libsolidity/codegen/ABIFunctions.cpp
@@ -120,7 +120,7 @@ string ABIFunctions::tupleDecoder(TypePointers const& _types, bool _fromMemory)
 
 		Whiskers templ(R"(
 			function <functionName>(headStart, dataEnd) -> <valueReturnParams> {
-				switch slt(sub(dataEnd, headStart), <minimumSize>) case 1 { revert(0, 0) }
+				if slt(sub(dataEnd, headStart), <minimumSize>) { revert(0, 0) }
 				<decodeElements>
 			}
 		)");
@@ -151,7 +151,7 @@ string ABIFunctions::tupleDecoder(TypePointers const& _types, bool _fromMemory)
 				R"(
 				{
 					let offset := <load>(add(headStart, <pos>))
-					switch gt(offset, 0xffffffffffffffff) case 1 { revert(0, 0) }
+					if gt(offset, 0xffffffffffffffff) { revert(0, 0) }
 					<values> := <abiDecode>(add(headStart, offset), dataEnd)
 				}
 				)" :
@@ -1134,7 +1134,7 @@ string ABIFunctions::abiDecodingFunctionArray(ArrayType const& _type, bool _from
 			R"(
 				// <readableTypeName>
 				function <functionName>(offset, end) -> array {
-					switch slt(add(offset, 0x1f), end) case 0 { revert(0, 0) }
+					if iszero(slt(add(offset, 0x1f), end)) { revert(0, 0) }
 					let length := <retrieveLength>
 					array := <allocate>(<allocationSize>(length))
 					let dst := array
@@ -1169,7 +1169,7 @@ string ABIFunctions::abiDecodingFunctionArray(ArrayType const& _type, bool _from
 		else
 		{
 			string baseEncodedSize = toCompactHexWithPrefix(_type.baseType()->calldataEncodedSize());
-			templ("staticBoundsCheck", "switch gt(add(src, mul(length, " + baseEncodedSize + ")), end) case 1 { revert(0, 0) }");
+			templ("staticBoundsCheck", "if gt(add(src, mul(length, " + baseEncodedSize + ")), end) { revert(0, 0) }");
 			templ("retrieveElementPos", "src");
 			templ("baseEncodedSize", baseEncodedSize);
 		}
@@ -1197,11 +1197,11 @@ string ABIFunctions::abiDecodingFunctionCalldataArray(ArrayType const& _type)
 			templ = R"(
 				// <readableTypeName>
 				function <functionName>(offset, end) -> arrayPos, length {
-					switch slt(add(offset, 0x1f), end) case 0 { revert(0, 0) }
+					if iszero(slt(add(offset, 0x1f), end)) { revert(0, 0) }
 					length := calldataload(offset)
-					switch gt(length, 0xffffffffffffffff) case 1 { revert(0, 0) }
+					if gt(length, 0xffffffffffffffff) { revert(0, 0) }
 					arrayPos := add(offset, 0x20)
-					switch gt(add(arrayPos, mul(<length>, <baseEncodedSize>)), end) case 1 { revert(0, 0) }
+					if gt(add(arrayPos, mul(<length>, <baseEncodedSize>)), end) { revert(0, 0) }
 				}
 			)";
 		else
@@ -1209,7 +1209,7 @@ string ABIFunctions::abiDecodingFunctionCalldataArray(ArrayType const& _type)
 				// <readableTypeName>
 				function <functionName>(offset, end) -> arrayPos {
 					arrayPos := offset
-					switch gt(add(arrayPos, mul(<length>, <baseEncodedSize>)), end) case 1 { revert(0, 0) }
+					if gt(add(arrayPos, mul(<length>, <baseEncodedSize>)), end) { revert(0, 0) }
 				}
 			)";
 		Whiskers w{templ};
@@ -1235,13 +1235,13 @@ string ABIFunctions::abiDecodingFunctionByteArray(ArrayType const& _type, bool _
 		Whiskers templ(
 			R"(
 				function <functionName>(offset, end) -> array {
-					switch slt(add(offset, 0x1f), end) case 0 { revert(0, 0) }
+					if iszero(slt(add(offset, 0x1f), end)) { revert(0, 0) }
 					let length := <load>(offset)
 					array := <allocate>(<allocationSize>(length))
 					mstore(array, length)
 					let src := add(offset, 0x20)
 					let dst := add(array, 0x20)
-					switch gt(add(src, length), end) case 1 { revert(0, 0) }
+					if gt(add(src, length), end) { revert(0, 0) }
 					<copyToMemFun>(src, dst, length)
 				}
 			)"
@@ -1268,7 +1268,7 @@ string ABIFunctions::abiDecodingFunctionStruct(StructType const& _type, bool _fr
 		Whiskers templ(R"(
 			// <readableTypeName>
 			function <functionName>(headStart, end) -> value {
-				switch slt(sub(end, headStart), <minimumSize>) case 1 { revert(0, 0) }
+				if slt(sub(end, headStart), <minimumSize>) { revert(0, 0) }
 				value := <allocate>(<memorySize>)
 				<#members>
 				{
@@ -1296,7 +1296,7 @@ string ABIFunctions::abiDecodingFunctionStruct(StructType const& _type, bool _fr
 				dynamic ?
 				R"(
 					let offset := <load>(add(headStart, <pos>))
-					switch gt(offset, 0xffffffffffffffff) case 1 { revert(0, 0) }
+					if gt(offset, 0xffffffffffffffff) { revert(0, 0) }
 					mstore(add(value, <memoryOffset>), <abiDecode>(add(headStart, offset), end))
 				)" :
 				R"(
@@ -1501,7 +1501,7 @@ string ABIFunctions::arrayAllocationSizeFunction(ArrayType const& _type)
 		Whiskers w(R"(
 			function <functionName>(length) -> size {
 				// Make sure we can allocate memory without overflow
-				switch gt(length, 0xffffffffffffffff) case 1 { revert(0, 0) }
+				if gt(length, 0xffffffffffffffff) { revert(0, 0) }
 				size := <allocationSize>
 				<addLengthSlot>
 			}
@@ -1620,7 +1620,7 @@ string ABIFunctions::allocationFunction()
 				memPtr := mload(<freeMemoryPointer>)
 				let newFreePtr := add(memPtr, size)
 				// protect against overflow
-				switch or(gt(newFreePtr, 0xffffffffffffffff), lt(newFreePtr, memPtr)) case 1 { revert(0, 0) }
+				if or(gt(newFreePtr, 0xffffffffffffffff), lt(newFreePtr, memPtr)) { revert(0, 0) }
 				mstore(<freeMemoryPointer>, newFreePtr)
 			}
 		)")
diff --git a/libsolidity/codegen/Compiler.cpp b/libsolidity/codegen/Compiler.cpp
index 44264a07..d3afada5 100644
--- a/libsolidity/codegen/Compiler.cpp
+++ b/libsolidity/codegen/Compiler.cpp
@@ -51,6 +51,7 @@ void Compiler::compileClone(
 	map<ContractDefinition const*, eth::Assembly const*> const& _contracts
 )
 {
+	solAssert(!_contract.isLibrary(), "");
 	ContractCompiler runtimeCompiler(nullptr, m_runtimeContext, m_optimize);
 	ContractCompiler cloneCompiler(&runtimeCompiler, m_context, m_optimize);
 	m_runtimeSub = cloneCompiler.compileClone(_contract, _contracts);
diff --git a/libsolidity/codegen/CompilerContext.cpp b/libsolidity/codegen/CompilerContext.cpp
index ce9c3b7f..7a88475a 100644
--- a/libsolidity/codegen/CompilerContext.cpp
+++ b/libsolidity/codegen/CompilerContext.cpp
@@ -319,14 +319,19 @@ void CompilerContext::appendInlineAssembly(
 	ErrorList errors;
 	ErrorReporter errorReporter(errors);
 	auto scanner = make_shared<Scanner>(CharStream(_assembly), "--CODEGEN--");
-	auto parserResult = assembly::Parser(errorReporter).parse(scanner);
+	auto parserResult = assembly::Parser(errorReporter, assembly::AsmFlavour::Strict).parse(scanner);
 #ifdef SOL_OUTPUT_ASM
 	cout << assembly::AsmPrinter()(*parserResult) << endl;
 #endif
 	assembly::AsmAnalysisInfo analysisInfo;
 	bool analyzerResult = false;
 	if (parserResult)
-		analyzerResult = assembly::AsmAnalyzer(analysisInfo, errorReporter, false, identifierAccess.resolve).analyze(*parserResult);
+		analyzerResult = assembly::AsmAnalyzer(
+			analysisInfo,
+			errorReporter,
+			assembly::AsmFlavour::Strict,
+			identifierAccess.resolve
+		).analyze(*parserResult);
 	if (!parserResult || !errorReporter.errors().empty() || !analyzerResult)
 	{
 		string message =
@@ -347,6 +352,9 @@ void CompilerContext::appendInlineAssembly(
 
 	solAssert(errorReporter.errors().empty(), "Failed to analyze inline assembly block.");
 	assembly::CodeGenerator::assemble(*parserResult, analysisInfo, *m_asm, identifierAccess, _system);
+
+	// Reset the source location to the one of the node (instead of the CODEGEN source location)
+	updateSourceLocation();
 }
 
 FunctionDefinition const& CompilerContext::resolveVirtualFunction(
diff --git a/libsolidity/codegen/CompilerContext.h b/libsolidity/codegen/CompilerContext.h
index 7743fd3f..a155a3a5 100644
--- a/libsolidity/codegen/CompilerContext.h
+++ b/libsolidity/codegen/CompilerContext.h
@@ -174,6 +174,9 @@ public:
 	eth::AssemblyItem appendData(bytes const& _data) { return m_asm->append(_data); }
 	/// Appends the address (virtual, will be filled in by linker) of a library.
 	void appendLibraryAddress(std::string const& _identifier) { m_asm->appendLibraryAddress(_identifier); }
+	/// Appends a zero-address that can be replaced by something else at deploy time (if the
+	/// position in bytecode is known).
+	void appendDeployTimeAddress() { m_asm->append(eth::PushDeployTimeAddress); }
 	/// Resets the stack of visited nodes with a new stack having only @c _node
 	void resetVisitedNodes(ASTNode const* _node);
 	/// Pops the stack of visited nodes
@@ -187,8 +190,8 @@ public:
 	CompilerContext& operator<<(u256 const& _value) { m_asm->append(_value); return *this; }
 	CompilerContext& operator<<(bytes const& _data) { m_asm->append(_data); return *this; }
 
-	/// Appends inline assembly. @a _replacements are string-matching replacements that are performed
-	/// prior to parsing the inline assembly.
+	/// Appends inline assembly (strict mode).
+	/// @a _replacements are string-matching replacements that are performed prior to parsing the inline assembly.
 	/// @param _localVariables assigns stack positions to variables with the last one being the stack top
 	/// @param _system if true, this is a "system-level" assembly where all functions use named labels.
 	void appendInlineAssembly(
diff --git a/libsolidity/codegen/ContractCompiler.cpp b/libsolidity/codegen/ContractCompiler.cpp
index a81ba518..f463db94 100644
--- a/libsolidity/codegen/ContractCompiler.cpp
+++ b/libsolidity/codegen/ContractCompiler.cpp
@@ -64,6 +64,12 @@ void ContractCompiler::compileContract(
 )
 {
 	CompilerContext::LocationSetter locationSetter(m_context, _contract);
+
+	if (_contract.isLibrary())
+		// Check whether this is a call (true) or a delegatecall (false).
+		// This has to be the first code in the contract.
+		appendDelegatecallCheck();
+
 	initializeContext(_contract, _contracts);
 	appendFunctionSelector(_contract);
 	appendMissingFunctions();
@@ -75,8 +81,13 @@ size_t ContractCompiler::compileConstructor(
 )
 {
 	CompilerContext::LocationSetter locationSetter(m_context, _contract);
-	initializeContext(_contract, _contracts);
-	return packIntoContractCreator(_contract);
+	if (_contract.isLibrary())
+		return deployLibrary(_contract);
+	else
+	{
+		initializeContext(_contract, _contracts);
+		return packIntoContractCreator(_contract);
+	}
 }
 
 size_t ContractCompiler::compileClone(
@@ -122,6 +133,7 @@ void ContractCompiler::appendCallValueCheck()
 
 void ContractCompiler::appendInitAndConstructorCode(ContractDefinition const& _contract)
 {
+	solAssert(!_contract.isLibrary(), "Tried to initialize library.");
 	CompilerContext::LocationSetter locationSetter(m_context, _contract);
 	// Determine the arguments that are used for the base constructors.
 	std::vector<ContractDefinition const*> const& bases = _contract.annotation().linearizedBaseContracts;
@@ -163,6 +175,7 @@ void ContractCompiler::appendInitAndConstructorCode(ContractDefinition const& _c
 size_t ContractCompiler::packIntoContractCreator(ContractDefinition const& _contract)
 {
 	solAssert(!!m_runtimeCompiler, "");
+	solAssert(!_contract.isLibrary(), "Tried to use contract creator or library.");
 
 	appendInitAndConstructorCode(_contract);
 
@@ -188,6 +201,34 @@ size_t ContractCompiler::packIntoContractCreator(ContractDefinition const& _cont
 	return m_context.runtimeSub();
 }
 
+size_t ContractCompiler::deployLibrary(ContractDefinition const& _contract)
+{
+	solAssert(!!m_runtimeCompiler, "");
+	solAssert(_contract.isLibrary(), "Tried to deploy contract as library.");
+
+	CompilerContext::LocationSetter locationSetter(m_context, _contract);
+
+	solAssert(m_context.runtimeSub() != size_t(-1), "Runtime sub not registered");
+	m_context.pushSubroutineSize(m_context.runtimeSub());
+	m_context.pushSubroutineOffset(m_context.runtimeSub());
+	m_context.appendInlineAssembly(R"(
+	{
+		// If code starts at 11, an mstore(0) writes to the full PUSH20 plus data
+		// without the need for a shift.
+		let codepos := 11
+		codecopy(codepos, subOffset, subSize)
+		// Check that the first opcode is a PUSH20
+		switch eq(0x73, byte(0, mload(codepos)))
+		case 0 { invalid() }
+		mstore(0, address())
+		mstore8(codepos, 0x73)
+		return(codepos, subSize)
+	}
+	)", {"subSize", "subOffset"});
+
+	return m_context.runtimeSub();
+}
+
 void ContractCompiler::appendBaseConstructor(FunctionDefinition const& _constructor)
 {
 	CompilerContext::LocationSetter locationSetter(m_context, _constructor);
@@ -244,11 +285,26 @@ void ContractCompiler::appendConstructor(FunctionDefinition const& _constructor)
 	_constructor.accept(*this);
 }
 
+void ContractCompiler::appendDelegatecallCheck()
+{
+	// Special constant that will be replaced by the address at deploy time.
+	// At compilation time, this is just "PUSH20 00...000".
+	m_context.appendDeployTimeAddress();
+	m_context << Instruction::ADDRESS << Instruction::EQ;
+	// The result on the stack is
+	// "We have not been called via DELEGATECALL".
+}
+
 void ContractCompiler::appendFunctionSelector(ContractDefinition const& _contract)
 {
 	map<FixedHash<4>, FunctionTypePointer> interfaceFunctions = _contract.interfaceFunctions();
 	map<FixedHash<4>, const eth::AssemblyItem> callDataUnpackerEntryPoints;
 
+	if (_contract.isLibrary())
+	{
+		solAssert(m_context.stackHeight() == 1, "CALL / DELEGATECALL flag expected.");
+	}
+
 	FunctionDefinition const* fallback = _contract.fallbackFunction();
 	eth::AssemblyItem notFound = m_context.newTag();
 	// directly jump to fallback if the data is too short to contain a function selector
@@ -260,7 +316,7 @@ void ContractCompiler::appendFunctionSelector(ContractDefinition const& _contrac
 	if (!interfaceFunctions.empty())
 		CompilerUtils(m_context).loadFromMemory(0, IntegerType(CompilerUtils::dataStartOffset * 8), true);
 
-	// stack now is: 1 0 <funhash>
+	// stack now is: <can-call-non-view-functions>? <funhash>
 	for (auto const& it: interfaceFunctions)
 	{
 		callDataUnpackerEntryPoints.insert(std::make_pair(it.first, m_context.newTag()));
@@ -272,6 +328,7 @@ void ContractCompiler::appendFunctionSelector(ContractDefinition const& _contrac
 	m_context << notFound;
 	if (fallback)
 	{
+		solAssert(!_contract.isLibrary(), "");
 		if (!fallback->isPayable())
 			appendCallValueCheck();
 
@@ -291,6 +348,13 @@ void ContractCompiler::appendFunctionSelector(ContractDefinition const& _contrac
 		CompilerContext::LocationSetter locationSetter(m_context, functionType->declaration());
 
 		m_context << callDataUnpackerEntryPoints.at(it.first);
+		if (_contract.isLibrary() && functionType->stateMutability() > StateMutability::View)
+		{
+			// If the function is not a view function and is called without DELEGATECALL,
+			// we revert.
+			m_context << dupInstruction(2);
+			m_context.appendConditionalRevert();
+		}
 		m_context.setStackOffset(0);
 		// We have to allow this for libraries, because value of the previous
 		// call is still visible in the delegatecall.
@@ -441,6 +505,7 @@ void ContractCompiler::registerStateVariables(ContractDefinition const& _contrac
 
 void ContractCompiler::initializeStateVariables(ContractDefinition const& _contract)
 {
+	solAssert(!_contract.isLibrary(), "Tried to initialize state variables of library.");
 	for (VariableDeclaration const* variable: _contract.stateVariables())
 		if (variable->value() && !variable->isConstant())
 			ExpressionCompiler(m_context, m_optimise).appendStateVariableInitialization(*variable);
diff --git a/libsolidity/codegen/ContractCompiler.h b/libsolidity/codegen/ContractCompiler.h
index 7c5ee59f..1fd80d05 100644
--- a/libsolidity/codegen/ContractCompiler.h
+++ b/libsolidity/codegen/ContractCompiler.h
@@ -75,10 +75,19 @@ private:
 	/// with a new and initialized context. Adds the constructor code.
 	/// @returns the identifier of the runtime sub assembly
 	size_t packIntoContractCreator(ContractDefinition const& _contract);
+	/// Appends code that deploys the given contract as a library.
+	/// Will also add code that modifies the contract in memory by injecting the current address
+	/// for the call protector.
+	size_t deployLibrary(ContractDefinition const& _contract);
 	/// Appends state variable initialisation and constructor code.
 	void appendInitAndConstructorCode(ContractDefinition const& _contract);
 	void appendBaseConstructor(FunctionDefinition const& _constructor);
 	void appendConstructor(FunctionDefinition const& _constructor);
+	/// Appends code that returns a boolean flag on the stack that tells whether
+	/// the contract has been called via delegatecall (false) or regular call (true).
+	/// This is done by inserting a specific push constant as the first instruction
+	/// whose data will be modified in memory at deploy time.
+	void appendDelegatecallCheck();
 	void appendFunctionSelector(ContractDefinition const& _contract);
 	void appendCallValueCheck();
 	/// Creates code that unpacks the arguments for the given function represented by a vector of TypePointers.
diff --git a/libsolidity/codegen/ExpressionCompiler.cpp b/libsolidity/codegen/ExpressionCompiler.cpp
index bb8c4a94..8e1cf019 100644
--- a/libsolidity/codegen/ExpressionCompiler.cpp
+++ b/libsolidity/codegen/ExpressionCompiler.cpp
@@ -1014,6 +1014,30 @@ bool ExpressionCompiler::visit(MemberAccess const& _memberAccess)
 			_memberAccess.expression().accept(*this);
 		return false;
 	}
+	// Another special case for `this.f.selector` which does not need the address.
+	// There are other uses of `.selector` which do need the address, but we want this
+	// specific use to be a pure expression.
+	if (
+		_memberAccess.expression().annotation().type->category() == Type::Category::Function &&
+		member == "selector"
+	)
+		if (auto const* expr = dynamic_cast<MemberAccess const*>(&_memberAccess.expression()))
+			if (auto const* exprInt = dynamic_cast<Identifier const*>(&expr->expression()))
+				if (exprInt->name() == "this")
+					if (Declaration const* declaration = expr->annotation().referencedDeclaration)
+					{
+						u256 identifier;
+						if (auto const* variable = dynamic_cast<VariableDeclaration const*>(declaration))
+							identifier = FunctionType(*variable).externalIdentifier();
+						else if (auto const* function = dynamic_cast<FunctionDefinition const*>(declaration))
+							identifier = FunctionType(*function).externalIdentifier();
+						else
+							solAssert(false, "Contract member is neither variable nor function.");
+						m_context << identifier;
+						/// need to store store it as bytes4
+						utils().leftShiftNumberOnStack(224);
+						return false;
+					}
 
 	_memberAccess.expression().accept(*this);
 	switch (_memberAccess.expression().annotation().type->category())