diff --git a/libsolidity/interface/StandardCompiler.cpp b/libsolidity/interface/StandardCompiler.cpp
index 5510b543077c..b908ab0cc6fd 100644
--- a/libsolidity/interface/StandardCompiler.cpp
+++ b/libsolidity/interface/StandardCompiler.cpp
@@ -1638,7 +1638,7 @@ Json StandardCompiler::compileYul(InputsAndSettings _inputsAndSettings)
 		return output;
 	}
 
-	std::string contractName = stack.parserResult()->name.str();
+	std::string contractName = stack.parserResult()->name;
 
 	bool const wildcardMatchesExperimental = true;
 	if (isArtifactRequested(_inputsAndSettings.outputSelection, sourceName, contractName, "ir", wildcardMatchesExperimental))
diff --git a/libyul/AsmAnalysis.cpp b/libyul/AsmAnalysis.cpp
index ac97f988d47d..38b9c782e0fc 100644
--- a/libyul/AsmAnalysis.cpp
+++ b/libyul/AsmAnalysis.cpp
@@ -428,7 +428,7 @@ std::vector<YulString> AsmAnalyzer::operator()(FunctionCall const& _funCall)
 				if (functionName == "datasize" || functionName == "dataoffset")
 				{
 					auto const& argumentAsLiteral = std::get<Literal>(arg);
-					if (!m_dataNames.count(YulString(formatLiteral(argumentAsLiteral))))
+					if (!m_dataNames.count(formatLiteral(argumentAsLiteral)))
 						m_errorReporter.typeError(
 							3517_error,
 							nativeLocationOf(arg),
diff --git a/libyul/AsmAnalysis.h b/libyul/AsmAnalysis.h
index c49e6855914d..9dd4b2292383 100644
--- a/libyul/AsmAnalysis.h
+++ b/libyul/AsmAnalysis.h
@@ -61,7 +61,7 @@ class AsmAnalyzer
 		langutil::ErrorReporter& _errorReporter,
 		Dialect const& _dialect,
 		ExternalIdentifierAccess::Resolver _resolver = ExternalIdentifierAccess::Resolver(),
-		std::set<YulString> _dataNames = {}
+		std::set<std::string> _dataNames = {}
 	):
 		m_resolver(std::move(_resolver)),
 		m_info(_analysisInfo),
@@ -128,7 +128,7 @@ class AsmAnalyzer
 	langutil::EVMVersion m_evmVersion;
 	Dialect const& m_dialect;
 	/// Names of data objects to be referenced by builtin functions with literal arguments.
-	std::set<YulString> m_dataNames;
+	std::set<std::string> m_dataNames;
 	ForLoop const* m_currentForLoop = nullptr;
 	/// Worst side effects encountered during analysis (including within defined functions).
 	SideEffects m_sideEffects;
diff --git a/libyul/Object.cpp b/libyul/Object.cpp
index 260cb733011f..76d8bdc66780 100644
--- a/libyul/Object.cpp
+++ b/libyul/Object.cpp
@@ -40,7 +40,7 @@ using namespace solidity::yul;
 
 std::string Data::toString(Dialect const*, DebugInfoSelection const&, CharStreamProvider const*) const
 {
-	return "data \"" + name.str() + "\" hex\"" + util::toHex(data) + "\"";
+	return "data \"" + name + "\" hex\"" + util::toHex(data) + "\"";
 }
 
 std::string Object::toString(
@@ -72,7 +72,7 @@ std::string Object::toString(
 	for (auto const& obj: subObjects)
 		inner += "\n" + obj->toString(_dialect, _debugInfoSelection, _soliditySourceProvider);
 
-	return useSrcComment + "object \"" + name.str() + "\" {\n" + indent(inner) + "\n}";
+	return useSrcComment + "object \"" + name + "\" {\n" + indent(inner) + "\n}";
 }
 
 Json Data::toJson() const
@@ -97,62 +97,61 @@ Json Object::toJson() const
 
 	Json ret;
 	ret["nodeType"] = "YulObject";
-	ret["name"] = name.str();
+	ret["name"] = name;
 	ret["code"] = codeJson;
 	ret["subObjects"] = subObjectsJson;
 	return ret;
 }
 
-std::set<YulString> Object::qualifiedDataNames() const
+std::set<std::string> Object::qualifiedDataNames() const
 {
-	std::set<YulString> qualifiedNames =
-		name.empty() || util::contains(name.str(), '.') ?
-		std::set<YulString>{} :
-		std::set<YulString>{name};
+	std::set<std::string> qualifiedNames =
+		name.empty() || util::contains(name, '.') ?
+		std::set<std::string>{} :
+		std::set<std::string>{name};
 	for (std::shared_ptr<ObjectNode> const& subObjectNode: subObjects)
 	{
 		yulAssert(qualifiedNames.count(subObjectNode->name) == 0, "");
-		if (util::contains(subObjectNode->name.str(), '.'))
+		if (util::contains(subObjectNode->name, '.'))
 			continue;
 		qualifiedNames.insert(subObjectNode->name);
 		if (auto const* subObject = dynamic_cast<Object const*>(subObjectNode.get()))
-			for (YulString const& subSubObj: subObject->qualifiedDataNames())
+			for (auto const& subSubObj: subObject->qualifiedDataNames())
 				if (subObject->name != subSubObj)
 				{
-					yulAssert(qualifiedNames.count(YulString{subObject->name.str() + "." + subSubObj.str()}) == 0, "");
-					qualifiedNames.insert(YulString{subObject->name.str() + "." + subSubObj.str()});
+					yulAssert(qualifiedNames.count(subObject->name + "." + subSubObj) == 0, "");
+					qualifiedNames.insert(subObject->name + "." + subSubObj);
 				}
 	}
 
-	yulAssert(qualifiedNames.count(YulString{}) == 0, "");
-	qualifiedNames.erase(YulString{});
+	yulAssert(qualifiedNames.count("") == 0, "");
 	return qualifiedNames;
 }
 
-std::vector<size_t> Object::pathToSubObject(YulString _qualifiedName) const
+std::vector<size_t> Object::pathToSubObject(std::string_view _qualifiedName) const
 {
 	yulAssert(_qualifiedName != name, "");
 	yulAssert(subIndexByName.count(name) == 0, "");
 
-	if (boost::algorithm::starts_with(_qualifiedName.str(), name.str() + "."))
-		_qualifiedName = YulString{_qualifiedName.str().substr(name.str().length() + 1)};
+	if (boost::algorithm::starts_with(_qualifiedName, name + "."))
+		_qualifiedName = _qualifiedName.substr(name.length() + 1);
 	yulAssert(!_qualifiedName.empty(), "");
 
 	std::vector<std::string> subObjectPathComponents;
-	boost::algorithm::split(subObjectPathComponents, _qualifiedName.str(), boost::is_any_of("."));
+	boost::algorithm::split(subObjectPathComponents, _qualifiedName, boost::is_any_of("."));
 
 	std::vector<size_t> path;
 	Object const* object = this;
 	for (std::string const& currentSubObjectName: subObjectPathComponents)
 	{
 		yulAssert(!currentSubObjectName.empty(), "");
-		auto subIndexIt = object->subIndexByName.find(YulString{currentSubObjectName});
+		auto subIndexIt = object->subIndexByName.find(currentSubObjectName);
 		yulAssert(
 			subIndexIt != object->subIndexByName.end(),
-			"Assembly object <" + _qualifiedName.str() + "> not found or does not contain code."
+			"Assembly object <" + std::string(_qualifiedName) + "> not found or does not contain code."
 		);
 		object = dynamic_cast<Object const*>(object->subObjects[subIndexIt->second].get());
-		yulAssert(object, "Assembly object <" + _qualifiedName.str() + "> not found or does not contain code.");
+		yulAssert(object, "Assembly object <" + std::string(_qualifiedName) + "> not found or does not contain code.");
 		yulAssert(object->subId != std::numeric_limits<size_t>::max(), "");
 		path.push_back({object->subId});
 	}
diff --git a/libyul/Object.h b/libyul/Object.h
index 54a8080d08c0..c1ca9244d98d 100644
--- a/libyul/Object.h
+++ b/libyul/Object.h
@@ -52,7 +52,7 @@ struct ObjectNode
 
 	/// Name of the object.
 	/// Can be empty since .yul files can also just contain code, without explicitly placing it in an object.
-	YulString name;
+	std::string name;
 	virtual std::string toString(
 		Dialect const* _dialect,
 		langutil::DebugInfoSelection const& _debugInfoSelection,
@@ -66,7 +66,7 @@ struct ObjectNode
  */
 struct Data: public ObjectNode
 {
-	Data(YulString _name, bytes _data): data(std::move(_data)) { name = _name; }
+	Data(std::string _name, bytes _data): data(std::move(_data)) { name = _name; }
 
 	bytes data;
 
@@ -102,7 +102,7 @@ struct Object: public ObjectNode
 	/// @returns the set of names of data objects accessible from within the code of
 	/// this object, including the name of object itself
 	/// Handles all names containing dots as reserved identifiers, not accessible as data.
-	std::set<YulString> qualifiedDataNames() const;
+	std::set<std::string> qualifiedDataNames() const;
 
 	/// @returns vector of subIDs if possible to reach subobject with @a _qualifiedName, throws otherwise
 	/// For "B.C" should return vector of two values if success (subId of B and subId of C in B).
@@ -114,14 +114,14 @@ struct Object: public ObjectNode
 	/// pathToSubObject("E2.F3.H4") == {1, 0, 2}
 	/// pathToSubObject("A1.E2") == {1}
 	/// The path must not lead to a @a Data object (will throw in that case).
-	std::vector<size_t> pathToSubObject(YulString _qualifiedName) const;
+	std::vector<size_t> pathToSubObject(std::string_view _qualifiedName) const;
 
 	/// sub id for object if it is subobject of another object, max value if it is not subobject
 	size_t subId = std::numeric_limits<size_t>::max();
 
 	std::shared_ptr<Block> code;
 	std::vector<std::shared_ptr<ObjectNode>> subObjects;
-	std::map<YulString, size_t> subIndexByName;
+	std::map<std::string, size_t, std::less<>> subIndexByName;
 	std::shared_ptr<yul::AsmAnalysisInfo> analysisInfo;
 
 	std::shared_ptr<ObjectDebugData const> debugData;
diff --git a/libyul/ObjectParser.cpp b/libyul/ObjectParser.cpp
index a02b9660b978..1f5363fd8d59 100644
--- a/libyul/ObjectParser.cpp
+++ b/libyul/ObjectParser.cpp
@@ -50,7 +50,7 @@ std::shared_ptr<Object> ObjectParser::parse(std::shared_ptr<Scanner> const& _sca
 		{
 			// Special case: Code-only form.
 			object = std::make_shared<Object>();
-			object->name = "object"_yulstring;
+			object->name = "object";
 			auto sourceNameMapping = tryParseSourceNameMapping();
 			object->debugData = std::make_shared<ObjectDebugData>(ObjectDebugData{sourceNameMapping});
 			object->code = parseBlock(sourceNameMapping);
@@ -185,7 +185,7 @@ void ObjectParser::parseData(Object& _containingObject)
 	);
 	advance();
 
-	YulString name = parseUniqueName(&_containingObject);
+	auto const name = parseUniqueName(&_containingObject);
 
 	if (currentToken() == Token::HexStringLiteral)
 		expectToken(Token::HexStringLiteral, false);
@@ -195,22 +195,26 @@ void ObjectParser::parseData(Object& _containingObject)
 	advance();
 }
 
-YulString ObjectParser::parseUniqueName(Object const* _containingObject)
+std::string ObjectParser::parseUniqueName(Object const* _containingObject)
 {
 	expectToken(Token::StringLiteral, false);
-	YulString name{currentLiteral()};
+	auto const name = currentLiteral();
 	if (name.empty())
 		parserError(3287_error, "Object name cannot be empty.");
 	else if (_containingObject && _containingObject->name == name)
 		parserError(8311_error, "Object name cannot be the same as the name of the containing object.");
 	else if (_containingObject && _containingObject->subIndexByName.count(name))
-		parserError(8794_error, "Object name \"" + name.str() + "\" already exists inside the containing object.");
+		parserError(8794_error, "Object name \"" + name + "\" already exists inside the containing object.");
 	advance();
 	return name;
 }
 
-void ObjectParser::addNamedSubObject(Object& _container, YulString _name, std::shared_ptr<ObjectNode> _subObject)
+void ObjectParser::addNamedSubObject(Object& _container, std::string_view const _name, std::shared_ptr<ObjectNode> _subObject)
 {
-	_container.subIndexByName[_name] = _container.subObjects.size();
+	_container.subIndexByName.emplace(
+		std::piecewise_construct,
+		std::forward_as_tuple(_name),
+		std::forward_as_tuple(_container.subObjects.size())
+	);
 	_container.subObjects.emplace_back(std::move(_subObject));
 }
diff --git a/libyul/ObjectParser.h b/libyul/ObjectParser.h
index 716a191ea878..08a852991203 100644
--- a/libyul/ObjectParser.h
+++ b/libyul/ObjectParser.h
@@ -63,8 +63,8 @@ class ObjectParser: public langutil::ParserBase
 	void parseData(Object& _containingObject);
 
 	/// Tries to parse a name that is non-empty and unique inside the containing object.
-	YulString parseUniqueName(Object const* _containingObject);
-	void addNamedSubObject(Object& _container, YulString _name, std::shared_ptr<ObjectNode> _subObject);
+	std::string parseUniqueName(Object const* _containingObject);
+	void addNamedSubObject(Object& _container, std::string_view _name, std::shared_ptr<ObjectNode> _subObject);
 
 	Dialect const& m_dialect;
 };
diff --git a/libyul/YulStack.cpp b/libyul/YulStack.cpp
index 94e9ad7a8d55..27b4b5526b85 100644
--- a/libyul/YulStack.cpp
+++ b/libyul/YulStack.cpp
@@ -198,7 +198,7 @@ void YulStack::optimize(Object& _object, bool _isCreation)
 	for (auto& subNode: _object.subObjects)
 		if (auto subObject = dynamic_cast<Object*>(subNode.get()))
 		{
-			bool isCreation = !boost::ends_with(subObject->name.str(), "_deployed");
+			bool isCreation = !boost::ends_with(subObject->name, "_deployed");
 			optimize(*subObject, isCreation);
 		}
 
diff --git a/libyul/backends/evm/EVMDialect.cpp b/libyul/backends/evm/EVMDialect.cpp
index 856689c91ad4..d3b9c34bcb5a 100644
--- a/libyul/backends/evm/EVMDialect.cpp
+++ b/libyul/backends/evm/EVMDialect.cpp
@@ -249,14 +249,14 @@ std::map<YulString, BuiltinFunctionForEVM> createBuiltins(langutil::EVMVersion _
 			yulAssert(_call.arguments.size() == 1, "");
 			Expression const& arg = _call.arguments.front();
 			YulString const dataName (formatLiteral(std::get<Literal>(arg)));
-			if (_context.currentObject->name == dataName)
+			if (_context.currentObject->name == dataName.str())
 				_assembly.appendAssemblySize();
 			else
 			{
 			std::vector<size_t> subIdPath =
-					_context.subIDs.count(dataName) == 0 ?
-						_context.currentObject->pathToSubObject(dataName) :
-						std::vector<size_t>{_context.subIDs.at(dataName)};
+					_context.subIDs.count(dataName.str()) == 0 ?
+						_context.currentObject->pathToSubObject(dataName.str()) :
+						std::vector<size_t>{_context.subIDs.at(dataName.str())};
 				yulAssert(!subIdPath.empty(), "Could not find assembly object <" + dataName.str() + ">.");
 				_assembly.appendDataSize(subIdPath);
 			}
@@ -270,14 +270,14 @@ std::map<YulString, BuiltinFunctionForEVM> createBuiltins(langutil::EVMVersion _
 			yulAssert(_call.arguments.size() == 1, "");
 			Expression const& arg = _call.arguments.front();
 			YulString const dataName (formatLiteral(std::get<Literal>(arg)));
-			if (_context.currentObject->name == dataName)
+			if (_context.currentObject->name == dataName.str())
 				_assembly.appendConstant(0);
 			else
 			{
 			std::vector<size_t> subIdPath =
-					_context.subIDs.count(dataName) == 0 ?
-						_context.currentObject->pathToSubObject(dataName) :
-						std::vector<size_t>{_context.subIDs.at(dataName)};
+					_context.subIDs.count(dataName.str()) == 0 ?
+						_context.currentObject->pathToSubObject(dataName.str()) :
+						std::vector<size_t>{_context.subIDs.at(dataName.str())};
 				yulAssert(!subIdPath.empty(), "Could not find assembly object <" + dataName.str() + ">.");
 				_assembly.appendDataOffset(subIdPath);
 			}
diff --git a/libyul/backends/evm/EVMDialect.h b/libyul/backends/evm/EVMDialect.h
index 28649f3e5e90..f0455a8e4240 100644
--- a/libyul/backends/evm/EVMDialect.h
+++ b/libyul/backends/evm/EVMDialect.h
@@ -45,7 +45,7 @@ struct BuiltinContext
 {
 	Object const* currentObject = nullptr;
 	/// Mapping from named objects to abstract assembly sub IDs.
-	std::map<YulString, AbstractAssembly::SubID> subIDs;
+	std::map<std::string, AbstractAssembly::SubID> subIDs;
 };
 
 struct BuiltinFunctionForEVM: public BuiltinFunction
diff --git a/libyul/backends/evm/EVMObjectCompiler.cpp b/libyul/backends/evm/EVMObjectCompiler.cpp
index 0bd064940eb7..81a345f90889 100644
--- a/libyul/backends/evm/EVMObjectCompiler.cpp
+++ b/libyul/backends/evm/EVMObjectCompiler.cpp
@@ -55,8 +55,8 @@ void EVMObjectCompiler::run(Object& _object, bool _optimize)
 	for (auto const& subNode: _object.subObjects)
 		if (auto* subObject = dynamic_cast<Object*>(subNode.get()))
 		{
-			bool isCreation = !boost::ends_with(subObject->name.str(), "_deployed");
-			auto subAssemblyAndID = m_assembly.createSubAssembly(isCreation, subObject->name.str());
+			bool isCreation = !boost::ends_with(subObject->name, "_deployed");
+			auto subAssemblyAndID = m_assembly.createSubAssembly(isCreation, subObject->name);
 			context.subIDs[subObject->name] = subAssemblyAndID.second;
 			subObject->subId = subAssemblyAndID.second;
 			compile(*subObject, *subAssemblyAndID.first, m_dialect, _optimize, m_eofVersion);
@@ -65,7 +65,7 @@ void EVMObjectCompiler::run(Object& _object, bool _optimize)
 		{
 			Data const& data = dynamic_cast<Data const&>(*subNode);
 			// Special handling of metadata.
-			if (data.name.str() == Object::metadataName())
+			if (data.name == Object::metadataName())
 				m_assembly.appendToAuxiliaryData(data.data);
 			else
 				context.subIDs[data.name] = m_assembly.appendData(data.data);
diff --git a/test/libsolidity/MemoryGuardTest.cpp b/test/libsolidity/MemoryGuardTest.cpp
index caa85c6fde8f..6e44afccf4f7 100644
--- a/test/libsolidity/MemoryGuardTest.cpp
+++ b/test/libsolidity/MemoryGuardTest.cpp
@@ -80,7 +80,7 @@ TestCase::TestResult MemoryGuardTest::run(std::ostream& _stream, std::string con
 		};
 		handleObject("creation", *object);
 		size_t deployedIndex = object->subIndexByName.at(
-			YulString(IRNames::deployedObject(compiler().contractDefinition(contractName)))
+			IRNames::deployedObject(compiler().contractDefinition(contractName))
 		);
 		handleObject("runtime", dynamic_cast<Object const&>(*object->subObjects[deployedIndex]));
 	}
diff --git a/tools/yulPhaser/Program.cpp b/tools/yulPhaser/Program.cpp
index 00abcc8e5c31..1586f602064b 100644
--- a/tools/yulPhaser/Program.cpp
+++ b/tools/yulPhaser/Program.cpp
@@ -135,7 +135,7 @@ std::variant<std::unique_ptr<Block>, ErrorList> Program::parseObject(Dialect con
 			// The other object references the nested one which makes analysis fail. Below we try to
 			// extract just the nested one for that reason. This is just a heuristic. If there's no
 			// subobject with such a suffix we fall back to accepting the whole object as is.
-			if (subObject != nullptr && subObject->name.str() == object->name.str() + "_deployed")
+			if (subObject != nullptr && subObject->name == object->name + "_deployed")
 			{
 				deployedObject = dynamic_cast<Object*>(subObject.get());
 				if (deployedObject != nullptr)