Codegen for object access.

14 files changed, 328 insertions, 146 deletions

diff --git a/libyul/AsmAnalysis.cpp b/libyul/AsmAnalysis.cpp
index 1be1cf1a..821da005 100644
--- a/libyul/AsmAnalysis.cpp
+++ b/libyul/AsmAnalysis.cpp
@@ -101,7 +101,7 @@ bool AsmAnalyzer::operator()(Literal const& _literal)
 	}
 	else if (_literal.kind == LiteralKind::Boolean)
 	{
-		solAssert(m_dialect.flavour == AsmFlavour::Yul, "");
+		solAssert(m_dialect->flavour == AsmFlavour::Yul, "");
 		solAssert(_literal.value == YulString{string("true")} || _literal.value == YulString{string("false")}, "");
 	}
 	m_info.stackHeightInfo[&_literal] = m_stackHeight;
@@ -164,7 +164,7 @@ bool AsmAnalyzer::operator()(Identifier const& _identifier)
 
 bool AsmAnalyzer::operator()(FunctionalInstruction const& _instr)
 {
-	solAssert(m_dialect.flavour != AsmFlavour::Yul, "");
+	solAssert(m_dialect->flavour != AsmFlavour::Yul, "");
 	bool success = true;
 	for (auto const& arg: _instr.arguments | boost::adaptors::reversed)
 		if (!expectExpression(arg))
@@ -182,9 +182,9 @@ bool AsmAnalyzer::operator()(ExpressionStatement const& _statement)
 {
 	int initialStackHeight = m_stackHeight;
 	bool success = boost::apply_visitor(*this, _statement.expression);
-	if (m_stackHeight != initialStackHeight && (m_dialect.flavour != AsmFlavour::Loose || m_errorTypeForLoose))
+	if (m_stackHeight != initialStackHeight && (m_dialect->flavour != AsmFlavour::Loose || m_errorTypeForLoose))
 	{
-		Error::Type errorType = m_dialect.flavour == AsmFlavour::Loose ? *m_errorTypeForLoose : Error::Type::TypeError;
+		Error::Type errorType = m_dialect->flavour == AsmFlavour::Loose ? *m_errorTypeForLoose : Error::Type::TypeError;
 		string msg =
 			"Top-level expressions are not supposed to return values (this expression returns " +
 			to_string(m_stackHeight - initialStackHeight) +
@@ -299,7 +299,7 @@ bool AsmAnalyzer::operator()(FunctionCall const& _funCall)
 	bool success = true;
 	size_t parameters = 0;
 	size_t returns = 0;
-	if (BuiltinFunction const* f = m_dialect.builtins->query(_funCall.functionName.name))
+	if (BuiltinFunction const* f = m_dialect->builtin(_funCall.functionName.name))
 	{
 		// TODO: compare types, too
 		parameters = f->parameters.size();
@@ -569,7 +569,7 @@ Scope& AsmAnalyzer::scope(Block const* _block)
 }
 void AsmAnalyzer::expectValidType(string const& type, SourceLocation const& _location)
 {
-	if (m_dialect.flavour != AsmFlavour::Yul)
+	if (m_dialect->flavour != AsmFlavour::Yul)
 		return;
 
 	if (!builtinTypes.count(type))
@@ -629,7 +629,7 @@ void AsmAnalyzer::warnOnInstructions(solidity::Instruction _instr, SourceLocatio
 
 	if (_instr == solidity::Instruction::JUMP || _instr == solidity::Instruction::JUMPI || _instr == solidity::Instruction::JUMPDEST)
 	{
-		if (m_dialect.flavour != AsmFlavour::Loose)
+		if (m_dialect->flavour != AsmFlavour::Loose)
 			solAssert(m_errorTypeForLoose && *m_errorTypeForLoose != Error::Type::Warning, "");
 
 		m_errorReporter.error(
@@ -644,7 +644,7 @@ void AsmAnalyzer::warnOnInstructions(solidity::Instruction _instr, SourceLocatio
 
 void AsmAnalyzer::checkLooseFeature(SourceLocation const& _location, string const& _description)
 {
-	if (m_dialect.flavour != AsmFlavour::Loose)
+	if (m_dialect->flavour != AsmFlavour::Loose)
 		solAssert(false, _description);
 	else if (m_errorTypeForLoose)
 		m_errorReporter.error(*m_errorTypeForLoose, _location, _description);
diff --git a/libyul/AsmAnalysis.h b/libyul/AsmAnalysis.h
index ec2b8868..21cc1142 100644
--- a/libyul/AsmAnalysis.h
+++ b/libyul/AsmAnalysis.h
@@ -59,7 +59,7 @@ public:
 		langutil::ErrorReporter& _errorReporter,
 		dev::solidity::EVMVersion _evmVersion,
 		boost::optional<langutil::Error::Type> _errorTypeForLoose,
-		Dialect _dialect = Dialect::looseAssemblyForEVM(),
+		std::shared_ptr<Dialect> _dialect,
 		ExternalIdentifierAccess::Resolver const& _resolver = ExternalIdentifierAccess::Resolver()
 	):
 		m_resolver(_resolver),
@@ -115,7 +115,7 @@ private:
 	AsmAnalysisInfo& m_info;
 	langutil::ErrorReporter& m_errorReporter;
 	dev::solidity::EVMVersion m_evmVersion;
-	Dialect m_dialect = Dialect::looseAssemblyForEVM();
+	std::shared_ptr<Dialect> m_dialect;
 	boost::optional<langutil::Error::Type> m_errorTypeForLoose;
 };
 
diff --git a/libyul/AsmParser.cpp b/libyul/AsmParser.cpp
index 33bb42f9..c7302063 100644
--- a/libyul/AsmParser.cpp
+++ b/libyul/AsmParser.cpp
@@ -107,14 +107,14 @@ Statement Parser::parseStatement()
 		return parseForLoop();
 	case Token::Assign:
 	{
-		if (m_dialect.flavour != AsmFlavour::Loose)
+		if (m_dialect->flavour != AsmFlavour::Loose)
 			break;
 		StackAssignment assignment = createWithLocation<StackAssignment>();
 		advance();
 		expectToken(Token::Colon);
 		assignment.variableName.location = location();
 		assignment.variableName.name = YulString(currentLiteral());
-		if (m_dialect.builtins->query(assignment.variableName.name))
+		if (m_dialect->builtin(assignment.variableName.name))
 			fatalParserError("Identifier expected, got builtin symbol.");
 		else if (instructions().count(assignment.variableName.name.str()))
 			fatalParserError("Identifier expected, got instruction name.");
@@ -176,9 +176,9 @@ Statement Parser::parseStatement()
 		if (currentToken() == Token::Assign && peekNextToken() != Token::Colon)
 		{
 			Assignment assignment = createWithLocation<Assignment>(identifier.location);
-			if (m_dialect.builtins->query(identifier.name))
+			if (m_dialect->builtin(identifier.name))
 				fatalParserError("Cannot assign to builtin function \"" + identifier.name.str() + "\".");
-			else if (m_dialect.flavour != AsmFlavour::Yul && instructions().count(identifier.name.str()))
+			else if (m_dialect->flavour != AsmFlavour::Yul && instructions().count(identifier.name.str()))
 				fatalParserError("Cannot use instruction names for identifier names.");
 			advance();
 			assignment.variableNames.emplace_back(identifier);
@@ -189,7 +189,7 @@ Statement Parser::parseStatement()
 		else
 		{
 			// label
-			if (m_dialect.flavour != AsmFlavour::Loose)
+			if (m_dialect->flavour != AsmFlavour::Loose)
 				fatalParserError("Labels are not supported.");
 			Label label = createWithLocation<Label>(identifier.location);
 			label.name = identifier.name;
@@ -197,7 +197,7 @@ Statement Parser::parseStatement()
 		}
 	}
 	default:
-		if (m_dialect.flavour != AsmFlavour::Loose)
+		if (m_dialect->flavour != AsmFlavour::Loose)
 			fatalParserError("Call or assignment expected.");
 		break;
 	}
@@ -273,7 +273,7 @@ Expression Parser::parseExpression()
 				instructionNames().at(instr.instruction) +
 				"\" not allowed in this context."
 			);
-		if (m_dialect.flavour != AsmFlavour::Loose && currentToken() != Token::LParen)
+		if (m_dialect->flavour != AsmFlavour::Loose && currentToken() != Token::LParen)
 			fatalParserError(
 				"Non-functional instructions are not allowed in this context."
 			);
@@ -293,7 +293,7 @@ Expression Parser::parseExpression()
 	else if (operation.type() == typeid(Instruction))
 	{
 		// Instructions not taking arguments are allowed as expressions.
-		solAssert(m_dialect.flavour == AsmFlavour::Loose, "");
+		solAssert(m_dialect->flavour == AsmFlavour::Loose, "");
 		Instruction& instr = boost::get<Instruction>(operation);
 		return FunctionalInstruction{std::move(instr.location), instr.instruction, {}};
 	}
@@ -362,9 +362,9 @@ Parser::ElementaryOperation Parser::parseElementaryOperation()
 		else
 			literal = YulString{currentLiteral()};
 		// first search the set of builtins, then the instructions.
-		if (m_dialect.builtins->query(literal))
+		if (m_dialect->builtin(literal))
 			ret = Identifier{location(), literal};
-		else if (m_dialect.flavour != AsmFlavour::Yul && instructions().count(literal.str()))
+		else if (m_dialect->flavour != AsmFlavour::Yul && instructions().count(literal.str()))
 		{
 			dev::solidity::Instruction const& instr = instructions().at(literal.str());
 			ret = Instruction{location(), instr};
@@ -405,7 +405,7 @@ Parser::ElementaryOperation Parser::parseElementaryOperation()
 			{}
 		};
 		advance();
-		if (m_dialect.flavour == AsmFlavour::Yul)
+		if (m_dialect->flavour == AsmFlavour::Yul)
 		{
 			expectToken(Token::Colon);
 			literal.location.end = endPosition();
@@ -418,7 +418,7 @@ Parser::ElementaryOperation Parser::parseElementaryOperation()
 	}
 	default:
 		fatalParserError(
-			m_dialect.flavour == AsmFlavour::Yul ?
+			m_dialect->flavour == AsmFlavour::Yul ?
 			"Literal or identifier expected." :
 			"Literal, identifier or instruction expected."
 		);
@@ -488,7 +488,7 @@ Expression Parser::parseCall(Parser::ElementaryOperation&& _initialOp)
 	RecursionGuard recursionGuard(*this);
 	if (_initialOp.type() == typeid(Instruction))
 	{
-		solAssert(m_dialect.flavour != AsmFlavour::Yul, "Instructions are invalid in Yul");
+		solAssert(m_dialect->flavour != AsmFlavour::Yul, "Instructions are invalid in Yul");
 		Instruction& instruction = boost::get<Instruction>(_initialOp);
 		FunctionalInstruction ret;
 		ret.instruction = instruction.instruction;
@@ -559,7 +559,7 @@ Expression Parser::parseCall(Parser::ElementaryOperation&& _initialOp)
 	}
 	else
 		fatalParserError(
-			m_dialect.flavour == AsmFlavour::Yul ?
+			m_dialect->flavour == AsmFlavour::Yul ?
 			"Function name expected." :
 			"Assembly instruction or function name required in front of \"(\")"
 		);
@@ -572,7 +572,7 @@ TypedName Parser::parseTypedName()
 	RecursionGuard recursionGuard(*this);
 	TypedName typedName = createWithLocation<TypedName>();
 	typedName.name = expectAsmIdentifier();
-	if (m_dialect.flavour == AsmFlavour::Yul)
+	if (m_dialect->flavour == AsmFlavour::Yul)
 	{
 		expectToken(Token::Colon);
 		typedName.location.end = endPosition();
@@ -584,7 +584,7 @@ TypedName Parser::parseTypedName()
 YulString Parser::expectAsmIdentifier()
 {
 	YulString name = YulString{currentLiteral()};
-	if (m_dialect.flavour == AsmFlavour::Yul)
+	if (m_dialect->flavour == AsmFlavour::Yul)
 	{
 		switch (currentToken())
 		{
@@ -598,7 +598,7 @@ YulString Parser::expectAsmIdentifier()
 			break;
 		}
 	}
-	else if (m_dialect.builtins->query(name))
+	else if (m_dialect->builtin(name))
 		fatalParserError("Cannot use builtin function name \"" + name.str() + "\" as identifier name.");
 	else if (instructions().count(name.str()))
 		fatalParserError("Cannot use instruction names for identifier names.");
diff --git a/libyul/AsmParser.h b/libyul/AsmParser.h
index b40a717c..a02f0b4d 100644
--- a/libyul/AsmParser.h
+++ b/libyul/AsmParser.h
@@ -38,7 +38,7 @@ namespace yul
 class Parser: public langutil::ParserBase
 {
 public:
-	explicit Parser(langutil::ErrorReporter& _errorReporter, Dialect _dialect = Dialect::looseAssemblyForEVM()):
+	explicit Parser(langutil::ErrorReporter& _errorReporter, std::shared_ptr<Dialect> _dialect):
 		ParserBase(_errorReporter), m_dialect(std::move(_dialect)) {}
 
 	/// Parses an inline assembly block starting with `{` and ending with `}`.
@@ -86,7 +86,7 @@ protected:
 	static bool isValidNumberLiteral(std::string const& _literal);
 
 private:
-	Dialect m_dialect = Dialect::looseAssemblyForEVM();
+	std::shared_ptr<Dialect> m_dialect;
 };
 
 }
diff --git a/libyul/CMakeLists.txt b/libyul/CMakeLists.txt
index 7d1ec6ba..74a5703c 100644
--- a/libyul/CMakeLists.txt
+++ b/libyul/CMakeLists.txt
@@ -10,6 +10,7 @@ add_library(yul
 	ObjectParser.cpp
 	backends/evm/EVMAssembly.cpp
 	backends/evm/EVMCodeTransform.cpp
+	backends/evm/EVMDialect.cpp
 	backends/evm/EVMObjectCompiler.cpp
 	optimiser/ASTCopier.cpp
 	optimiser/ASTWalker.cpp
diff --git a/libyul/Dialect.cpp b/libyul/Dialect.cpp
index 99718787..f6985c17 100644
--- a/libyul/Dialect.cpp
+++ b/libyul/Dialect.cpp
@@ -20,57 +20,10 @@
 
 #include <libyul/Dialect.h>
 
+#include <libyul/Object.h>
+#include <libyul/backends/evm/AbstractAssembly.h>
+
 #include <map>
 
 using namespace yul;
 using namespace std;
-
-namespace
-{
-
-void addFunction(
-	map<YulString, BuiltinFunction>& _repository,
-	string const& _name,
-	size_t _params,
-	size_t _returns,
-	bool _movable
-)
-{
-	_repository[YulString{_name}] = BuiltinFunction{
-		YulString{_name},
-		vector<Type>(_params),
-		vector<Type>(_returns),
-		_movable
-	};
-}
-
-class GenericBuiltins: public Builtins
-{
-public:
-	GenericBuiltins(map<YulString, BuiltinFunction> const& _functions): m_functions(_functions) {}
-	BuiltinFunction const* query(YulString _name) const
-	{
-		auto it = m_functions.find(_name);
-		if (it != end(m_functions))
-			return &it->second;
-		else
-			return nullptr;
-	}
-private:
-	map<YulString, BuiltinFunction> const& m_functions;
-};
-
-}
-
-Dialect Dialect::strictAssemblyForEVMObjects()
-{
-	static map<YulString, BuiltinFunction> functions;
-	if (functions.empty())
-	{
-		addFunction(functions, "datasize", 1, 1, true);
-		addFunction(functions, "dataoffset", 1, 1, true);
-		addFunction(functions, "datacopy", 3, 0, false);
-	}
-	// The EVM instructions will be moved to builtins at some point.
-	return Dialect{AsmFlavour::Strict, std::make_shared<GenericBuiltins>(functions)};
-}
diff --git a/libyul/Dialect.h b/libyul/Dialect.h
index b78f1aaf..2def566c 100644
--- a/libyul/Dialect.h
+++ b/libyul/Dialect.h
@@ -22,7 +22,9 @@
 
 #include <libyul/YulString.h>
 
-#include <memory>
+#include <boost/noncopyable.hpp>
+
+#include <vector>
 
 namespace yul
 {
@@ -45,38 +47,19 @@ struct BuiltinFunction
 	bool movable;
 };
 
-/**
- * Class to query for builtin functions and their semantics.
- */
-struct Builtins
+struct Dialect: boost::noncopyable
 {
-	virtual ~Builtins() = default;
+	AsmFlavour const flavour = AsmFlavour::Loose;
 	/// @returns the builtin function of the given name or a nullptr if it is not a builtin function.
-	virtual BuiltinFunction const* query(YulString /*_name*/) const { return nullptr; }
-};
+	virtual BuiltinFunction const* builtin(YulString /*_name*/) const { return nullptr; }
 
-struct Dialect
-{
-	AsmFlavour flavour = AsmFlavour::Loose;
-	std::shared_ptr<Builtins> builtins;
+	Dialect(AsmFlavour _flavour): flavour(_flavour) {}
+	virtual ~Dialect() {}
 
-	Dialect(AsmFlavour _flavour, std::shared_ptr<Builtins> _builtins):
-		flavour(_flavour), builtins(std::move(_builtins))
-	{}
-	static Dialect looseAssemblyForEVM()
-	{
-		return Dialect{AsmFlavour::Loose, std::make_shared<Builtins>()};
-	}
-	static Dialect strictAssemblyForEVM()
-	{
-		// The EVM instructions will be moved to builtins at some point.
-		return Dialect{AsmFlavour::Strict, std::make_shared<Builtins>()};
-	}
-	static Dialect strictAssemblyForEVMObjects();
-	static Dialect yul()
+	static std::shared_ptr<Dialect> yul()
 	{
 		// Will have to add builtins later.
-		return Dialect{AsmFlavour::Yul, std::make_shared<Builtins>()};
+		return std::make_shared<Dialect>(AsmFlavour::Yul);
 	}
 };
 
diff --git a/libyul/ObjectParser.h b/libyul/ObjectParser.h
index 59efb8ab..e39f24cd 100644
--- a/libyul/ObjectParser.h
+++ b/libyul/ObjectParser.h
@@ -47,7 +47,7 @@ class ObjectParser: public langutil::ParserBase
 public:
 	explicit ObjectParser(
 		langutil::ErrorReporter& _errorReporter,
-		Dialect _dialect = Dialect::looseAssemblyForEVM()
+		std::shared_ptr<Dialect> _dialect
 	):
 		ParserBase(_errorReporter), m_dialect(std::move(_dialect)) {}
 
@@ -67,7 +67,7 @@ private:
 	YulString parseUniqueName(Object const* _containingObject);
 	void addNamedSubObject(Object& _container, YulString _name, std::shared_ptr<ObjectNode> _subObject);
 
-	Dialect m_dialect;
+	std::shared_ptr<Dialect> m_dialect;
 };
 
 }
diff --git a/libyul/backends/evm/EVMCodeTransform.cpp b/libyul/backends/evm/EVMCodeTransform.cpp
index 025f937f..bd18985c 100644
--- a/libyul/backends/evm/EVMCodeTransform.cpp
+++ b/libyul/backends/evm/EVMCodeTransform.cpp
@@ -97,7 +97,7 @@ CodeTransform::CodeTransform(
 	AsmAnalysisInfo& _analysisInfo,
 	Block const& _block,
 	bool _allowStackOpt,
-	bool _yul,
+	EVMDialect const& _dialect,
 	bool _evm15,
 	ExternalIdentifierAccess const& _identifierAccess,
 	bool _useNamedLabelsForFunctions,
@@ -106,8 +106,8 @@ CodeTransform::CodeTransform(
 ):
 	m_assembly(_assembly),
 	m_info(_analysisInfo),
+	m_dialect(_dialect),
 	m_allowStackOpt(_allowStackOpt),
-	m_yul(_yul),
 	m_evm15(_evm15),
 	m_useNamedLabelsForFunctions(_useNamedLabelsForFunctions),
 	m_identifierAccess(_identifierAccess),
@@ -267,35 +267,46 @@ void CodeTransform::operator()(FunctionCall const& _call)
 {
 	solAssert(m_scope, "");
 
-	m_assembly.setSourceLocation(_call.location);
-	EVMAssembly::LabelID returnLabel(-1); // only used for evm 1.0
-	if (!m_evm15)
+	if (BuiltinFunctionForEVM const* builtin = m_dialect.builtin(_call.functionName.name))
 	{
-		returnLabel = m_assembly.newLabelId();
-		m_assembly.appendLabelReference(returnLabel);
-		m_stackAdjustment++;
+		builtin->generateCode(_call, m_assembly, [&]() {
+			for (auto const& arg: _call.arguments | boost::adaptors::reversed)
+				visitExpression(arg);
+			m_assembly.setSourceLocation(_call.location);
+		});
 	}
-
-	Scope::Function* function = nullptr;
-	solAssert(m_scope->lookup(_call.functionName.name, Scope::NonconstVisitor(
-		[=](Scope::Variable&) { solAssert(false, "Expected function name."); },
-		[=](Scope::Label&) { solAssert(false, "Expected function name."); },
-		[&](Scope::Function& _function) { function = &_function; }
-	)), "Function name not found.");
-	solAssert(function, "");
-	solAssert(function->arguments.size() == _call.arguments.size(), "");
-	for (auto const& arg: _call.arguments | boost::adaptors::reversed)
-		visitExpression(arg);
-	m_assembly.setSourceLocation(_call.location);
-	if (m_evm15)
-		m_assembly.appendJumpsub(functionEntryID(_call.functionName.name, *function), function->arguments.size(), function->returns.size());
 	else
 	{
-		m_assembly.appendJumpTo(functionEntryID(_call.functionName.name, *function), function->returns.size() - function->arguments.size() - 1);
-		m_assembly.appendLabel(returnLabel);
-		m_stackAdjustment--;
+		m_assembly.setSourceLocation(_call.location);
+		EVMAssembly::LabelID returnLabel(-1); // only used for evm 1.0
+		if (!m_evm15)
+		{
+			returnLabel = m_assembly.newLabelId();
+			m_assembly.appendLabelReference(returnLabel);
+			m_stackAdjustment++;
+		}
+
+		Scope::Function* function = nullptr;
+		solAssert(m_scope->lookup(_call.functionName.name, Scope::NonconstVisitor(
+			[=](Scope::Variable&) { solAssert(false, "Expected function name."); },
+			[=](Scope::Label&) { solAssert(false, "Expected function name."); },
+			[&](Scope::Function& _function) { function = &_function; }
+		)), "Function name not found.");
+		solAssert(function, "");
+		solAssert(function->arguments.size() == _call.arguments.size(), "");
+		for (auto const& arg: _call.arguments | boost::adaptors::reversed)
+			visitExpression(arg);
+		m_assembly.setSourceLocation(_call.location);
+		if (m_evm15)
+			m_assembly.appendJumpsub(functionEntryID(_call.functionName.name, *function), function->arguments.size(), function->returns.size());
+		else
+		{
+			m_assembly.appendJumpTo(functionEntryID(_call.functionName.name, *function), function->returns.size() - function->arguments.size() - 1);
+			m_assembly.appendLabel(returnLabel);
+			m_stackAdjustment--;
+		}
+		checkStackHeight(&_call);
 	}
-	checkStackHeight(&_call);
 }
 
 void CodeTransform::operator()(FunctionalInstruction const& _instruction)
diff --git a/libyul/backends/evm/EVMCodeTransform.h b/libyul/backends/evm/EVMCodeTransform.h
index e305a68c..28ef4e45 100644
--- a/libyul/backends/evm/EVMCodeTransform.h
+++ b/libyul/backends/evm/EVMCodeTransform.h
@@ -20,10 +20,10 @@
 
 #include <libyul/backends/evm/EVMAssembly.h>
 
+#include <libyul/backends/evm/EVMDialect.h>
 #include <libyul/optimiser/ASTWalker.h>
 #include <libyul/AsmDataForward.h>
 #include <libyul/AsmScope.h>
-#include <libyul/Dialect.h>
 
 #include <boost/variant.hpp>
 #include <boost/optional.hpp>
@@ -87,8 +87,8 @@ public:
 		AbstractAssembly& _assembly,
 		AsmAnalysisInfo& _analysisInfo,
 		Block const& _block,
+		EVMDialect const& _dialect,
 		bool _allowStackOpt = false,
-		Dialect const& _dialect,
 		bool _evm15 = false,
 		ExternalIdentifierAccess const& _identifierAccess = ExternalIdentifierAccess(),
 		bool _useNamedLabelsForFunctions = false
@@ -115,7 +115,7 @@ protected:
 		AsmAnalysisInfo& _analysisInfo,
 		Block const& _block,
 		bool _allowStackOpt,
-		Dialect const& _dialect,
+		EVMDialect const& _dialect,
 		bool _evm15,
 		ExternalIdentifierAccess const& _identifierAccess,
 		bool _useNamedLabelsForFunctions,
@@ -179,10 +179,10 @@ private:
 	AbstractAssembly& m_assembly;
 	AsmAnalysisInfo& m_info;
 	Scope* m_scope = nullptr;
+	EVMDialect const& m_dialect;
 	bool const m_allowStackOpt = true;
-	Dialect const& m_dialect;
-	bool m_evm15 = false;
-	bool m_useNamedLabelsForFunctions = false;
+	bool const m_evm15 = false;
+	bool const m_useNamedLabelsForFunctions = false;
 	ExternalIdentifierAccess m_identifierAccess;
 	/// Adjustment between the stack height as determined during the analysis phase
 	/// and the stack height in the assembly. This is caused by an initial stack being present
diff --git a/libyul/backends/evm/EVMDialect.cpp b/libyul/backends/evm/EVMDialect.cpp
new file mode 100644
index 00000000..33ee19d4
--- /dev/null
+++ b/libyul/backends/evm/EVMDialect.cpp
@@ -0,0 +1,141 @@
+/*
+	This file is part of solidity.
+
+	solidity is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	solidity is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/**
+ * Yul dialects for EVM.
+ */
+
+#include <libyul/backends/evm/EVMDialect.h>
+
+#include <libyul/AsmAnalysisInfo.h>
+#include <libyul/AsmData.h>
+#include <libyul/Object.h>
+#include <libyul/backends/evm/AbstractAssembly.h>
+
+#include <liblangutil/Exceptions.h>
+
+#include <libyul/Exceptions.h>
+
+#include <boost/range/adaptor/reversed.hpp>
+
+using namespace std;
+using namespace dev;
+using namespace yul;
+using namespace dev::solidity;
+
+
+EVMDialect::EVMDialect(AsmFlavour _flavour, bool _objectAccess):
+	Dialect(_flavour), m_objectAccess(_objectAccess)
+{
+	// The EVM instructions will be moved to builtins at some point.
+	if (!m_objectAccess)
+		return;
+
+	addFunction("datasize", 1, 1, true, [this](
+		FunctionCall const& _call,
+		AbstractAssembly& _assembly,
+		std::function<void()>
+	) {
+		yulAssert(m_currentObject, "No object available.");
+		yulAssert(_call.arguments.size() == 1, "");
+		Expression const& arg = _call.arguments.front();
+		YulString dataName = boost::get<Literal>(arg).value;
+		if (m_currentObject->name == dataName)
+			_assembly.appendAssemblySize();
+		else
+			_assembly.appendDataSize(m_subIDs.at(dataName));
+	});
+	addFunction("dataoffset", 1, 1, true, [this](
+		FunctionCall const& _call,
+		AbstractAssembly& _assembly,
+		std::function<void()>
+	) {
+		yulAssert(m_currentObject, "No object available.");
+		yulAssert(_call.arguments.size() == 1, "");
+		Expression const& arg = _call.arguments.front();
+		YulString dataName = boost::get<Literal>(arg).value;
+		if (m_currentObject->name == dataName)
+			_assembly.appendConstant(0);
+		else
+			_assembly.appendDataOffset(m_subIDs.at(dataName));
+	});
+	addFunction("datacopy", 3, 0, false, [](
+		FunctionCall const&,
+		AbstractAssembly& _assembly,
+		std::function<void()> _visitArguments
+	) {
+		_visitArguments();
+		_assembly.appendInstruction(solidity::Instruction::CODECOPY);
+	});
+}
+
+BuiltinFunctionForEVM const* EVMDialect::builtin(YulString _name) const
+{
+	auto it = m_functions.find(_name);
+	if (it != m_functions.end())
+		return &it->second;
+	else
+		return nullptr;
+}
+
+shared_ptr<EVMDialect> EVMDialect::looseAssemblyForEVM()
+{
+	return make_shared<EVMDialect>(AsmFlavour::Loose, false);
+}
+
+shared_ptr<EVMDialect> EVMDialect::strictAssemblyForEVM()
+{
+	return make_shared<EVMDialect>(AsmFlavour::Strict, false);
+}
+
+shared_ptr<EVMDialect> EVMDialect::strictAssemblyForEVMObjects()
+{
+	return make_shared<EVMDialect>(AsmFlavour::Strict, true);
+}
+
+shared_ptr<yul::EVMDialect> EVMDialect::yulForEVM()
+{
+	return make_shared<EVMDialect>(AsmFlavour::Yul, false);
+}
+
+void EVMDialect::setSubIDs(map<YulString, AbstractAssembly::SubID> _subIDs)
+{
+	yulAssert(m_objectAccess, "Sub IDs set with dialect that does not support object access.");
+	m_subIDs = std::move(_subIDs);
+}
+
+void EVMDialect::setCurrentObject(Object const* _object)
+{
+	yulAssert(m_objectAccess, "Current object set with dialect that does not support object access.");
+	m_currentObject = _object;
+}
+
+void EVMDialect::addFunction(
+	string _name,
+	size_t _params,
+	size_t _returns,
+	bool _movable,
+	std::function<void(FunctionCall const&, AbstractAssembly&, std::function<void()>)> _generateCode
+)
+{
+	YulString name{std::move(_name)};
+	BuiltinFunctionForEVM& f = m_functions[name];
+	f.name = name;
+	f.parameters.resize(_params);
+	f.returns.resize(_returns);
+	f.movable = _movable;
+	f.generateCode = std::move(_generateCode);
+}
diff --git a/libyul/backends/evm/EVMDialect.h b/libyul/backends/evm/EVMDialect.h
new file mode 100644
index 00000000..feb00b03
--- /dev/null
+++ b/libyul/backends/evm/EVMDialect.h
@@ -0,0 +1,85 @@
+/*
+	This file is part of solidity.
+
+	solidity is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	solidity is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/**
+ * Yul dialects for EVM.
+ */
+
+#pragma once
+
+#include <libyul/Dialect.h>
+
+#include <libyul/backends/evm/AbstractAssembly.h>
+
+#include <map>
+
+namespace yul
+{
+
+class YulString;
+using Type = YulString;
+struct FunctionCall;
+struct Object;
+
+struct BuiltinFunctionForEVM: BuiltinFunction
+{
+	/// Function to generate code for the given function call and append it to the abstract
+	/// assembly. The third parameter is called to visit (and generate code for) the arguments
+	/// from right to left.
+	std::function<void(FunctionCall const&, AbstractAssembly&, std::function<void()>)> generateCode;
+};
+
+/**
+ * Yul dialect for EVM as a backend.
+ * The main difference is that the builtin functions take an AbstractAssembly for the
+ * code generation.
+ */
+struct EVMDialect: public Dialect
+{
+	EVMDialect(AsmFlavour _flavour, bool _objectAccess);
+
+	/// @returns the builtin function of the given name or a nullptr if it is not a builtin function.
+	BuiltinFunctionForEVM const* builtin(YulString _name) const override;
+
+	static std::shared_ptr<EVMDialect> looseAssemblyForEVM();
+	static std::shared_ptr<EVMDialect> strictAssemblyForEVM();
+	static std::shared_ptr<EVMDialect> strictAssemblyForEVMObjects();
+	static std::shared_ptr<EVMDialect> yulForEVM();
+
+	bool providesObjectAccess() const { return m_objectAccess; }
+
+	/// Sets the mapping of current sub assembly IDs. Used during code generation.
+	void setSubIDs(std::map<YulString, AbstractAssembly::SubID> _subIDs);
+	/// Sets the current object. Used during code generation.
+	void setCurrentObject(Object const* _object);
+
+private:
+	void addFunction(
+		std::string _name,
+		size_t _params,
+		size_t _returns,
+		bool _movable,
+		std::function<void(FunctionCall const&, AbstractAssembly&, std::function<void()>)> _generateCode
+	);
+
+	bool m_objectAccess;
+	Object const* m_currentObject = nullptr;
+	/// Mapping from named objects to abstract assembly sub IDs.
+	std::map<YulString, AbstractAssembly::SubID> m_subIDs;
+	std::map<YulString, BuiltinFunctionForEVM> m_functions;
+};
+
+}
diff --git a/libyul/backends/evm/EVMObjectCompiler.cpp b/libyul/backends/evm/EVMObjectCompiler.cpp
index ec849faa..3f7634b2 100644
--- a/libyul/backends/evm/EVMObjectCompiler.cpp
+++ b/libyul/backends/evm/EVMObjectCompiler.cpp
@@ -21,13 +21,15 @@
 #include <libyul/backends/evm/EVMObjectCompiler.h>
 
 #include <libyul/backends/evm/EVMCodeTransform.h>
+#include <libyul/backends/evm/EVMDialect.h>
+
 #include <libyul/Object.h>
 #include <libyul/Exceptions.h>
 
 using namespace yul;
 using namespace std;
 
-void EVMObjectCompiler::compile(Object& _object, AbstractAssembly& _assembly, Dialect const& _dialect, bool _evm15, bool _optimize)
+void EVMObjectCompiler::compile(Object& _object, AbstractAssembly& _assembly, EVMDialect& _dialect, bool _evm15, bool _optimize)
 {
 	EVMObjectCompiler compiler(_assembly, _dialect, _evm15);
 	compiler.run(_object, _optimize);
@@ -50,7 +52,13 @@ void EVMObjectCompiler::run(Object& _object, bool _optimize)
 			subIDs[data.name] = m_assembly.appendData(data.data);
 		}
 
+	if (m_dialect.providesObjectAccess())
+	{
+		m_dialect.setSubIDs(std::move(subIDs));
+		m_dialect.setCurrentObject(&_object);
+	}
+
 	yulAssert(_object.analysisInfo, "No analysis info.");
 	yulAssert(_object.code, "No code.");
-	CodeTransform{m_assembly, *_object.analysisInfo, *_object.code, _optimize, m_yul, m_evm15, _optimize}(*_object.code);
+	CodeTransform{m_assembly, *_object.analysisInfo, *_object.code, m_dialect, _optimize, m_evm15}(*_object.code);
 }
diff --git a/libyul/backends/evm/EVMObjectCompiler.h b/libyul/backends/evm/EVMObjectCompiler.h
index bb265ff6..057521a8 100644
--- a/libyul/backends/evm/EVMObjectCompiler.h
+++ b/libyul/backends/evm/EVMObjectCompiler.h
@@ -23,21 +23,21 @@ namespace yul
 {
 struct Object;
 class AbstractAssembly;
-struct Dialect;
+struct EVMDialect;
 
 class EVMObjectCompiler
 {
 public:
-	static void compile(Object& _object, AbstractAssembly& _assembly, Dialect const& _dialect, bool _evm15, bool _optimize);
+	static void compile(Object& _object, AbstractAssembly& _assembly, EVMDialect& _dialect, bool _evm15, bool _optimize);
 private:
-	EVMObjectCompiler(AbstractAssembly& _assembly, Dialect const& _dialect, bool _evm15):
+	EVMObjectCompiler(AbstractAssembly& _assembly, EVMDialect& _dialect, bool _evm15):
 		m_assembly(_assembly), m_dialect(_dialect), m_evm15(_evm15)
 	{}
 
 	void run(Object& _object, bool _optimize);
 
 	AbstractAssembly& m_assembly;
-	Dialect const& m_dialect;
+	EVMDialect& m_dialect;
 	bool m_evm15 = false;
 };