Renaming libjulia to libyul

5 files changed, 1133 insertions, 0 deletions

diff --git a/libyul/backends/evm/AbstractAssembly.h b/libyul/backends/evm/AbstractAssembly.h
new file mode 100644
index 00000000..b6818923
--- /dev/null
+++ b/libyul/backends/evm/AbstractAssembly.h
@@ -0,0 +1,119 @@
+/*
+	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/>.
+*/
+/**
+ * @date 2017
+ * Abstract assembly interface, subclasses of which are to be used with the generic
+ * bytecode generator.
+ */
+
+#pragma once
+
+#include <libdevcore/CommonData.h>
+
+#include <functional>
+
+namespace dev
+{
+struct SourceLocation;
+namespace solidity
+{
+enum class Instruction: uint8_t;
+namespace assembly
+{
+struct Instruction;
+struct Identifier;
+}
+}
+namespace julia
+{
+
+///
+/// Assembly class that abstracts both the libevmasm assembly and the new Yul assembly.
+///
+class AbstractAssembly
+{
+public:
+	using LabelID = size_t;
+
+	virtual ~AbstractAssembly() {}
+
+	/// Set a new source location valid starting from the next instruction.
+	virtual void setSourceLocation(SourceLocation const& _location) = 0;
+	/// Retrieve the current height of the stack. This does not have to be zero
+	/// at the beginning.
+	virtual int stackHeight() const = 0;
+	/// Append an EVM instruction.
+	virtual void appendInstruction(solidity::Instruction _instruction) = 0;
+	/// Append a constant.
+	virtual void appendConstant(u256 const& _constant) = 0;
+	/// Append a label.
+	virtual void appendLabel(LabelID _labelId) = 0;
+	/// Append a label reference.
+	virtual void appendLabelReference(LabelID _labelId) = 0;
+	/// Generate a new unique label.
+	virtual LabelID newLabelId() = 0;
+	/// Returns a label identified by the given name. Creates it if it does not yet exist.
+	virtual LabelID namedLabel(std::string const& _name) = 0;
+	/// Append a reference to a to-be-linked symbol.
+	/// Currently, we assume that the value is always a 20 byte number.
+	virtual void appendLinkerSymbol(std::string const& _name) = 0;
+
+	/// Append a jump instruction.
+	/// @param _stackDiffAfter the stack adjustment after this instruction.
+	/// This is helpful to stack height analysis if there is no continuing control flow.
+	virtual void appendJump(int _stackDiffAfter) = 0;
+
+	/// Append a jump-to-immediate operation.
+	/// @param _stackDiffAfter the stack adjustment after this instruction.
+	virtual void appendJumpTo(LabelID _labelId, int _stackDiffAfter = 0) = 0;
+	/// Append a jump-to-if-immediate operation.
+	virtual void appendJumpToIf(LabelID _labelId) = 0;
+	/// Start a subroutine identified by @a _labelId that takes @a _arguments
+	/// stack slots as arguments.
+	virtual void appendBeginsub(LabelID _labelId, int _arguments) = 0;
+	/// Call a subroutine identified by @a _labelId, taking @a _arguments from the
+	/// stack upon call and putting @a _returns arguments onto the stack upon return.
+	virtual void appendJumpsub(LabelID _labelId, int _arguments, int _returns) = 0;
+	/// Return from a subroutine.
+	/// @param _stackDiffAfter the stack adjustment after this instruction.
+	virtual void appendReturnsub(int _returns, int _stackDiffAfter = 0) = 0;
+
+	/// Append the assembled size as a constant.
+	virtual void appendAssemblySize() = 0;
+};
+
+enum class IdentifierContext { LValue, RValue };
+
+/// Object that is used to resolve references and generate code for access to identifiers external
+/// to inline assembly (not used in standalone assembly mode).
+struct ExternalIdentifierAccess
+{
+	using Resolver = std::function<size_t(solidity::assembly::Identifier const&, IdentifierContext, bool /*_crossesFunctionBoundary*/)>;
+	/// Resolve an external reference given by the identifier in the given context.
+	/// @returns the size of the value (number of stack slots) or size_t(-1) if not found.
+	Resolver resolve;
+	using CodeGenerator = std::function<void(solidity::assembly::Identifier const&, IdentifierContext, julia::AbstractAssembly&)>;
+	/// Generate code for retrieving the value (rvalue context) or storing the value (lvalue context)
+	/// of an identifier. The code should be appended to the assembly. In rvalue context, the value is supposed
+	/// to be put onto the stack, in lvalue context, the value is assumed to be at the top of the stack.
+	CodeGenerator generateCode;
+};
+
+
+
+}
+}
diff --git a/libyul/backends/evm/EVMAssembly.cpp b/libyul/backends/evm/EVMAssembly.cpp
new file mode 100644
index 00000000..af0ddbb8
--- /dev/null
+++ b/libyul/backends/evm/EVMAssembly.cpp
@@ -0,0 +1,202 @@
+/*
+	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/>.
+*/
+/**
+ * Assembly interface for EVM and EVM1.5.
+ */
+
+#include <libyul/backends/evm/EVMAssembly.h>
+
+#include <libevmasm/Instruction.h>
+
+#include <libsolidity/interface/Exceptions.h>
+
+using namespace std;
+using namespace dev;
+using namespace dev::julia;
+
+namespace
+{
+/// Size of labels in bytes. Four-byte labels are required by some EVM1.5 instructions.
+size_t constexpr labelReferenceSize = 4;
+
+size_t constexpr assemblySizeReferenceSize = 4;
+}
+
+
+void EVMAssembly::setSourceLocation(SourceLocation const&)
+{
+	// Ignored for now;
+}
+
+void EVMAssembly::appendInstruction(solidity::Instruction _instr)
+{
+	m_bytecode.push_back(byte(_instr));
+	m_stackHeight += solidity::instructionInfo(_instr).ret - solidity::instructionInfo(_instr).args;
+}
+
+void EVMAssembly::appendConstant(u256 const& _constant)
+{
+	bytes data = toCompactBigEndian(_constant, 1);
+	appendInstruction(solidity::pushInstruction(data.size()));
+	m_bytecode += data;
+}
+
+void EVMAssembly::appendLabel(LabelID _labelId)
+{
+	setLabelToCurrentPosition(_labelId);
+	appendInstruction(solidity::Instruction::JUMPDEST);
+}
+
+void EVMAssembly::appendLabelReference(LabelID _labelId)
+{
+	solAssert(!m_evm15, "Cannot use plain label references in EMV1.5 mode.");
+	// @TODO we now always use labelReferenceSize for all labels, it could be shortened
+	// for some of them.
+	appendInstruction(solidity::pushInstruction(labelReferenceSize));
+	m_labelReferences[m_bytecode.size()] = _labelId;
+	m_bytecode += bytes(labelReferenceSize);
+}
+
+EVMAssembly::LabelID EVMAssembly::newLabelId()
+{
+	m_labelPositions[m_nextLabelId] = size_t(-1);
+	return m_nextLabelId++;
+}
+
+AbstractAssembly::LabelID EVMAssembly::namedLabel(string const& _name)
+{
+	solAssert(!_name.empty(), "");
+	if (!m_namedLabels.count(_name))
+		m_namedLabels[_name] = newLabelId();
+	return m_namedLabels[_name];
+}
+
+void EVMAssembly::appendLinkerSymbol(string const&)
+{
+	solAssert(false, "Linker symbols not yet implemented.");
+}
+
+void EVMAssembly::appendJump(int _stackDiffAfter)
+{
+	solAssert(!m_evm15, "Plain JUMP used for EVM 1.5");
+	appendInstruction(solidity::Instruction::JUMP);
+	m_stackHeight += _stackDiffAfter;
+}
+
+void EVMAssembly::appendJumpTo(LabelID _labelId, int _stackDiffAfter)
+{
+	if (m_evm15)
+	{
+		m_bytecode.push_back(byte(solidity::Instruction::JUMPTO));
+		appendLabelReferenceInternal(_labelId);
+		m_stackHeight += _stackDiffAfter;
+	}
+	else
+	{
+		appendLabelReference(_labelId);
+		appendJump(_stackDiffAfter);
+	}
+}
+
+void EVMAssembly::appendJumpToIf(LabelID _labelId)
+{
+	if (m_evm15)
+	{
+		m_bytecode.push_back(byte(solidity::Instruction::JUMPIF));
+		appendLabelReferenceInternal(_labelId);
+		m_stackHeight--;
+	}
+	else
+	{
+		appendLabelReference(_labelId);
+		appendInstruction(solidity::Instruction::JUMPI);
+	}
+}
+
+void EVMAssembly::appendBeginsub(LabelID _labelId, int _arguments)
+{
+	solAssert(m_evm15, "BEGINSUB used for EVM 1.0");
+	solAssert(_arguments >= 0, "");
+	setLabelToCurrentPosition(_labelId);
+	m_bytecode.push_back(byte(solidity::Instruction::BEGINSUB));
+	m_stackHeight += _arguments;
+}
+
+void EVMAssembly::appendJumpsub(LabelID _labelId, int _arguments, int _returns)
+{
+	solAssert(m_evm15, "JUMPSUB used for EVM 1.0");
+	solAssert(_arguments >= 0 && _returns >= 0, "");
+	m_bytecode.push_back(byte(solidity::Instruction::JUMPSUB));
+	appendLabelReferenceInternal(_labelId);
+	m_stackHeight += _returns - _arguments;
+}
+
+void EVMAssembly::appendReturnsub(int _returns, int _stackDiffAfter)
+{
+	solAssert(m_evm15, "RETURNSUB used for EVM 1.0");
+	solAssert(_returns >= 0, "");
+	m_bytecode.push_back(byte(solidity::Instruction::RETURNSUB));
+	m_stackHeight += _stackDiffAfter - _returns;
+}
+
+eth::LinkerObject EVMAssembly::finalize()
+{
+	size_t bytecodeSize = m_bytecode.size();
+	for (auto const& ref: m_assemblySizePositions)
+		updateReference(ref, assemblySizeReferenceSize, u256(bytecodeSize));
+
+	for (auto const& ref: m_labelReferences)
+	{
+		size_t referencePos = ref.first;
+		solAssert(m_labelPositions.count(ref.second), "");
+		size_t labelPos = m_labelPositions.at(ref.second);
+		solAssert(labelPos != size_t(-1), "Undefined but allocated label used.");
+		updateReference(referencePos, labelReferenceSize, u256(labelPos));
+	}
+
+	eth::LinkerObject obj;
+	obj.bytecode = m_bytecode;
+	return obj;
+}
+
+void EVMAssembly::setLabelToCurrentPosition(LabelID _labelId)
+{
+	solAssert(m_labelPositions.count(_labelId), "Label not found.");
+	solAssert(m_labelPositions[_labelId] == size_t(-1), "Label already set.");
+	m_labelPositions[_labelId] = m_bytecode.size();
+}
+
+void EVMAssembly::appendLabelReferenceInternal(LabelID _labelId)
+{
+	m_labelReferences[m_bytecode.size()] = _labelId;
+	m_bytecode += bytes(labelReferenceSize);
+}
+
+void EVMAssembly::appendAssemblySize()
+{
+	appendInstruction(solidity::pushInstruction(assemblySizeReferenceSize));
+	m_assemblySizePositions.push_back(m_bytecode.size());
+	m_bytecode += bytes(assemblySizeReferenceSize);
+}
+
+void EVMAssembly::updateReference(size_t pos, size_t size, u256 value)
+{
+	solAssert(m_bytecode.size() >= size && pos <= m_bytecode.size() - size, "");
+	solAssert(value < (u256(1) << (8 * size)), "");
+	for (size_t i = 0; i < size; i++)
+		m_bytecode[pos + i] = byte((value >> (8 * (size - i - 1))) & 0xff);
+}
diff --git a/libyul/backends/evm/EVMAssembly.h b/libyul/backends/evm/EVMAssembly.h
new file mode 100644
index 00000000..30abad97
--- /dev/null
+++ b/libyul/backends/evm/EVMAssembly.h
@@ -0,0 +1,97 @@
+/*
+	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/>.
+*/
+/**
+ * Assembly interface for EVM and EVM1.5.
+ */
+
+#pragma once
+
+#include <libyul/backends/evm/AbstractAssembly.h>
+
+#include <libevmasm/LinkerObject.h>
+
+#include <map>
+
+namespace dev
+{
+namespace julia
+{
+
+class EVMAssembly: public AbstractAssembly
+{
+public:
+	explicit EVMAssembly(bool _evm15 = false): m_evm15(_evm15) { }
+	virtual ~EVMAssembly() {}
+
+	/// Set a new source location valid starting from the next instruction.
+	virtual void setSourceLocation(SourceLocation const& _location) override;
+	/// Retrieve the current height of the stack. This does not have to be zero
+	/// at the beginning.
+	virtual int stackHeight() const override { return m_stackHeight; }
+	/// Append an EVM instruction.
+	virtual void appendInstruction(solidity::Instruction _instruction) override;
+	/// Append a constant.
+	virtual void appendConstant(u256 const& _constant) override;
+	/// Append a label.
+	virtual void appendLabel(LabelID _labelId) override;
+	/// Append a label reference.
+	virtual void appendLabelReference(LabelID _labelId) override;
+	/// Generate a new unique label.
+	virtual LabelID newLabelId() override;
+	/// Returns a label identified by the given name. Creates it if it does not yet exist.
+	virtual LabelID namedLabel(std::string const& _name) override;
+	/// Append a reference to a to-be-linked symbol.
+	/// Currently, we assume that the value is always a 20 byte number.
+	virtual void appendLinkerSymbol(std::string const& _name) override;
+
+	/// Append a jump instruction.
+	/// @param _stackDiffAfter the stack adjustment after this instruction.
+	virtual void appendJump(int _stackDiffAfter) override;
+	/// Append a jump-to-immediate operation.
+	virtual void appendJumpTo(LabelID _labelId, int _stackDiffAfter) override;
+	/// Append a jump-to-if-immediate operation.
+	virtual void appendJumpToIf(LabelID _labelId) override;
+	/// Start a subroutine.
+	virtual void appendBeginsub(LabelID _labelId, int _arguments) override;
+	/// Call a subroutine.
+	virtual void appendJumpsub(LabelID _labelId, int _arguments, int _returns) override;
+	/// Return from a subroutine.
+	virtual void appendReturnsub(int _returns, int _stackDiffAfter) override;
+
+	/// Append the assembled size as a constant.
+	virtual void appendAssemblySize() override;
+
+	/// Resolves references inside the bytecode and returns the linker object.
+	eth::LinkerObject finalize();
+
+private:
+	void setLabelToCurrentPosition(AbstractAssembly::LabelID _labelId);
+	void appendLabelReferenceInternal(AbstractAssembly::LabelID _labelId);
+	void updateReference(size_t pos, size_t size, u256 value);
+
+	bool m_evm15 = false; ///< if true, switch to evm1.5 mode
+	LabelID m_nextLabelId = 0;
+	int m_stackHeight = 0;
+	bytes m_bytecode;
+	std::map<std::string, LabelID> m_namedLabels;
+	std::map<LabelID, size_t> m_labelPositions;
+	std::map<size_t, LabelID> m_labelReferences;
+	std::vector<size_t> m_assemblySizePositions;
+};
+
+}
+}
diff --git a/libyul/backends/evm/EVMCodeTransform.cpp b/libyul/backends/evm/EVMCodeTransform.cpp
new file mode 100644
index 00000000..afc9e608
--- /dev/null
+++ b/libyul/backends/evm/EVMCodeTransform.cpp
@@ -0,0 +1,557 @@
+/*
+	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/>.
+*/
+/**
+ * Common code generator for translating Yul / inline assembly to EVM and EVM1.5.
+ */
+
+#include <libyul/backends/evm/EVMCodeTransform.h>
+
+#include <libsolidity/inlineasm/AsmAnalysisInfo.h>
+#include <libsolidity/inlineasm/AsmData.h>
+
+#include <libsolidity/interface/Exceptions.h>
+
+#include <boost/range/adaptor/reversed.hpp>
+
+using namespace std;
+using namespace dev;
+using namespace dev::julia;
+using namespace dev::solidity;
+
+using Scope = dev::solidity::assembly::Scope;
+
+void CodeTransform::operator()(VariableDeclaration const& _varDecl)
+{
+	solAssert(m_scope, "");
+
+	int const numVariables = _varDecl.variables.size();
+	int height = m_assembly.stackHeight();
+	if (_varDecl.value)
+	{
+		boost::apply_visitor(*this, *_varDecl.value);
+		expectDeposit(numVariables, height);
+	}
+	else
+	{
+		int variablesLeft = numVariables;
+		while (variablesLeft--)
+			m_assembly.appendConstant(u256(0));
+	}
+	for (auto const& variable: _varDecl.variables)
+	{
+		auto& var = boost::get<Scope::Variable>(m_scope->identifiers.at(variable.name));
+		m_context->variableStackHeights[&var] = height++;
+	}
+	checkStackHeight(&_varDecl);
+}
+
+void CodeTransform::operator()(Assignment const& _assignment)
+{
+	int height = m_assembly.stackHeight();
+	boost::apply_visitor(*this, *_assignment.value);
+	expectDeposit(_assignment.variableNames.size(), height);
+
+	m_assembly.setSourceLocation(_assignment.location);
+	generateMultiAssignment(_assignment.variableNames);
+	checkStackHeight(&_assignment);
+}
+
+void CodeTransform::operator()(StackAssignment const& _assignment)
+{
+	m_assembly.setSourceLocation(_assignment.location);
+	generateAssignment(_assignment.variableName);
+	checkStackHeight(&_assignment);
+}
+
+void CodeTransform::operator()(ExpressionStatement const& _statement)
+{
+	m_assembly.setSourceLocation(_statement.location);
+	boost::apply_visitor(*this, _statement.expression);
+	checkStackHeight(&_statement);
+}
+
+void CodeTransform::operator()(Label const& _label)
+{
+	m_assembly.setSourceLocation(_label.location);
+	solAssert(m_scope, "");
+	solAssert(m_scope->identifiers.count(_label.name), "");
+	Scope::Label& label = boost::get<Scope::Label>(m_scope->identifiers.at(_label.name));
+	m_assembly.appendLabel(labelID(label));
+	checkStackHeight(&_label);
+}
+
+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)
+	{
+		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);
+}
+
+void CodeTransform::operator()(FunctionalInstruction const& _instruction)
+{
+	if (m_evm15 && (
+		_instruction.instruction == solidity::Instruction::JUMP ||
+		_instruction.instruction == solidity::Instruction::JUMPI
+	))
+	{
+		bool const isJumpI = _instruction.instruction == solidity::Instruction::JUMPI;
+		if (isJumpI)
+		{
+			solAssert(_instruction.arguments.size() == 2, "");
+			visitExpression(_instruction.arguments.at(1));
+		}
+		else
+		{
+			solAssert(_instruction.arguments.size() == 1, "");
+		}
+		m_assembly.setSourceLocation(_instruction.location);
+		auto label = labelFromIdentifier(boost::get<assembly::Identifier>(_instruction.arguments.at(0)));
+		if (isJumpI)
+			m_assembly.appendJumpToIf(label);
+		else
+			m_assembly.appendJumpTo(label);
+	}
+	else
+	{
+		for (auto const& arg: _instruction.arguments | boost::adaptors::reversed)
+			visitExpression(arg);
+		m_assembly.setSourceLocation(_instruction.location);
+		m_assembly.appendInstruction(_instruction.instruction);
+	}
+	checkStackHeight(&_instruction);
+}
+
+void CodeTransform::operator()(assembly::Identifier const& _identifier)
+{
+	m_assembly.setSourceLocation(_identifier.location);
+	// First search internals, then externals.
+	solAssert(m_scope, "");
+	if (m_scope->lookup(_identifier.name, Scope::NonconstVisitor(
+		[=](Scope::Variable& _var)
+		{
+			if (int heightDiff = variableHeightDiff(_var, false))
+				m_assembly.appendInstruction(solidity::dupInstruction(heightDiff));
+			else
+				// Store something to balance the stack
+				m_assembly.appendConstant(u256(0));
+		},
+		[=](Scope::Label& _label)
+		{
+			m_assembly.appendLabelReference(labelID(_label));
+		},
+		[=](Scope::Function&)
+		{
+			solAssert(false, "Function not removed during desugaring.");
+		}
+	)))
+	{
+		return;
+	}
+	solAssert(
+		m_identifierAccess.generateCode,
+		"Identifier not found and no external access available."
+	);
+	m_identifierAccess.generateCode(_identifier, IdentifierContext::RValue, m_assembly);
+	checkStackHeight(&_identifier);
+}
+
+void CodeTransform::operator()(assembly::Literal const& _literal)
+{
+	m_assembly.setSourceLocation(_literal.location);
+	if (_literal.kind == assembly::LiteralKind::Number)
+		m_assembly.appendConstant(u256(_literal.value));
+	else if (_literal.kind == assembly::LiteralKind::Boolean)
+	{
+		if (_literal.value == "true")
+			m_assembly.appendConstant(u256(1));
+		else
+			m_assembly.appendConstant(u256(0));
+	}
+	else
+	{
+		solAssert(_literal.value.size() <= 32, "");
+		m_assembly.appendConstant(u256(h256(_literal.value, h256::FromBinary, h256::AlignLeft)));
+	}
+	checkStackHeight(&_literal);
+}
+
+void CodeTransform::operator()(assembly::Instruction const& _instruction)
+{
+	solAssert(!m_evm15 || _instruction.instruction != solidity::Instruction::JUMP, "Bare JUMP instruction used for EVM1.5");
+	solAssert(!m_evm15 || _instruction.instruction != solidity::Instruction::JUMPI, "Bare JUMPI instruction used for EVM1.5");
+	m_assembly.setSourceLocation(_instruction.location);
+	m_assembly.appendInstruction(_instruction.instruction);
+	checkStackHeight(&_instruction);
+}
+
+void CodeTransform::operator()(If const& _if)
+{
+	visitExpression(*_if.condition);
+	m_assembly.setSourceLocation(_if.location);
+	m_assembly.appendInstruction(solidity::Instruction::ISZERO);
+	AbstractAssembly::LabelID end = m_assembly.newLabelId();
+	m_assembly.appendJumpToIf(end);
+	(*this)(_if.body);
+	m_assembly.setSourceLocation(_if.location);
+	m_assembly.appendLabel(end);
+	checkStackHeight(&_if);
+}
+
+void CodeTransform::operator()(Switch const& _switch)
+{
+	//@TODO use JUMPV in EVM1.5?
+
+	visitExpression(*_switch.expression);
+	int expressionHeight = m_assembly.stackHeight();
+	map<Case const*, AbstractAssembly::LabelID> caseBodies;
+	AbstractAssembly::LabelID end = m_assembly.newLabelId();
+	for (Case const& c: _switch.cases)
+	{
+		if (c.value)
+		{
+			(*this)(*c.value);
+			m_assembly.setSourceLocation(c.location);
+			AbstractAssembly::LabelID bodyLabel = m_assembly.newLabelId();
+			caseBodies[&c] = bodyLabel;
+			solAssert(m_assembly.stackHeight() == expressionHeight + 1, "");
+			m_assembly.appendInstruction(solidity::dupInstruction(2));
+			m_assembly.appendInstruction(solidity::Instruction::EQ);
+			m_assembly.appendJumpToIf(bodyLabel);
+		}
+		else
+			// default case
+			(*this)(c.body);
+	}
+	m_assembly.setSourceLocation(_switch.location);
+	m_assembly.appendJumpTo(end);
+
+	size_t numCases = caseBodies.size();
+	for (auto const& c: caseBodies)
+	{
+		m_assembly.setSourceLocation(c.first->location);
+		m_assembly.appendLabel(c.second);
+		(*this)(c.first->body);
+		// Avoid useless "jump to next" for the last case.
+		if (--numCases > 0)
+		{
+			m_assembly.setSourceLocation(c.first->location);
+			m_assembly.appendJumpTo(end);
+		}
+	}
+
+	m_assembly.setSourceLocation(_switch.location);
+	m_assembly.appendLabel(end);
+	m_assembly.appendInstruction(solidity::Instruction::POP);
+	checkStackHeight(&_switch);
+}
+
+void CodeTransform::operator()(FunctionDefinition const& _function)
+{
+	solAssert(m_scope, "");
+	solAssert(m_scope->identifiers.count(_function.name), "");
+	Scope::Function& function = boost::get<Scope::Function>(m_scope->identifiers.at(_function.name));
+
+	int const localStackAdjustment = m_evm15 ? 0 : 1;
+	int height = localStackAdjustment;
+	solAssert(m_info.scopes.at(&_function.body), "");
+	Scope* varScope = m_info.scopes.at(m_info.virtualBlocks.at(&_function).get()).get();
+	solAssert(varScope, "");
+	for (auto const& v: _function.parameters | boost::adaptors::reversed)
+	{
+		auto& var = boost::get<Scope::Variable>(varScope->identifiers.at(v.name));
+		m_context->variableStackHeights[&var] = height++;
+	}
+
+	m_assembly.setSourceLocation(_function.location);
+	int stackHeightBefore = m_assembly.stackHeight();
+	AbstractAssembly::LabelID afterFunction = m_assembly.newLabelId();
+
+	if (m_evm15)
+	{
+		m_assembly.appendJumpTo(afterFunction, -stackHeightBefore);
+		m_assembly.appendBeginsub(functionEntryID(_function.name, function), _function.parameters.size());
+	}
+	else
+	{
+		m_assembly.appendJumpTo(afterFunction, -stackHeightBefore + height);
+		m_assembly.appendLabel(functionEntryID(_function.name, function));
+	}
+	m_stackAdjustment += localStackAdjustment;
+
+	for (auto const& v: _function.returnVariables)
+	{
+		auto& var = boost::get<Scope::Variable>(varScope->identifiers.at(v.name));
+		m_context->variableStackHeights[&var] = height++;
+		// Preset stack slots for return variables to zero.
+		m_assembly.appendConstant(u256(0));
+	}
+
+	CodeTransform(
+		m_assembly,
+		m_info,
+		m_yul,
+		m_evm15,
+		m_identifierAccess,
+		m_useNamedLabelsForFunctions,
+		localStackAdjustment,
+		m_context
+	)(_function.body);
+
+	{
+		// The stack layout here is:
+		// <return label>? <arguments...> <return values...>
+		// But we would like it to be:
+		// <return values...> <return label>?
+		// So we have to append some SWAP and POP instructions.
+
+		// This vector holds the desired target positions of all stack slots and is
+		// modified parallel to the actual stack.
+		vector<int> stackLayout;
+		if (!m_evm15)
+			stackLayout.push_back(_function.returnVariables.size()); // Move return label to the top
+		stackLayout += vector<int>(_function.parameters.size(), -1); // discard all arguments
+		for (size_t i = 0; i < _function.returnVariables.size(); ++i)
+			stackLayout.push_back(i); // Move return values down, but keep order.
+
+		solAssert(stackLayout.size() <= 17, "Stack too deep");
+		while (!stackLayout.empty() && stackLayout.back() != int(stackLayout.size() - 1))
+			if (stackLayout.back() < 0)
+			{
+				m_assembly.appendInstruction(solidity::Instruction::POP);
+				stackLayout.pop_back();
+			}
+			else
+			{
+				m_assembly.appendInstruction(swapInstruction(stackLayout.size() - stackLayout.back() - 1));
+				swap(stackLayout[stackLayout.back()], stackLayout.back());
+			}
+		for (int i = 0; size_t(i) < stackLayout.size(); ++i)
+			solAssert(i == stackLayout[i], "Error reshuffling stack.");
+	}
+
+	if (m_evm15)
+		m_assembly.appendReturnsub(_function.returnVariables.size(), stackHeightBefore);
+	else
+		m_assembly.appendJump(stackHeightBefore - _function.returnVariables.size());
+	m_stackAdjustment -= localStackAdjustment;
+	m_assembly.appendLabel(afterFunction);
+	checkStackHeight(&_function);
+}
+
+void CodeTransform::operator()(ForLoop const& _forLoop)
+{
+	Scope* originalScope = m_scope;
+	// We start with visiting the block, but not finalizing it.
+	m_scope = m_info.scopes.at(&_forLoop.pre).get();
+	int stackStartHeight = m_assembly.stackHeight();
+
+	visitStatements(_forLoop.pre.statements);
+
+	// TODO: When we implement break and continue, the labels and the stack heights at that point
+	// have to be stored in a stack.
+	AbstractAssembly::LabelID loopStart = m_assembly.newLabelId();
+	AbstractAssembly::LabelID loopEnd = m_assembly.newLabelId();
+	AbstractAssembly::LabelID postPart = m_assembly.newLabelId();
+
+	m_assembly.setSourceLocation(_forLoop.location);
+	m_assembly.appendLabel(loopStart);
+
+	visitExpression(*_forLoop.condition);
+	m_assembly.setSourceLocation(_forLoop.location);
+	m_assembly.appendInstruction(solidity::Instruction::ISZERO);
+	m_assembly.appendJumpToIf(loopEnd);
+
+	(*this)(_forLoop.body);
+
+	m_assembly.setSourceLocation(_forLoop.location);
+	m_assembly.appendLabel(postPart);
+
+	(*this)(_forLoop.post);
+
+	m_assembly.setSourceLocation(_forLoop.location);
+	m_assembly.appendJumpTo(loopStart);
+	m_assembly.appendLabel(loopEnd);
+
+	finalizeBlock(_forLoop.pre, stackStartHeight);
+	m_scope = originalScope;
+}
+
+void CodeTransform::operator()(Block const& _block)
+{
+	Scope* originalScope = m_scope;
+	m_scope = m_info.scopes.at(&_block).get();
+
+	int blockStartStackHeight = m_assembly.stackHeight();
+	visitStatements(_block.statements);
+
+	finalizeBlock(_block, blockStartStackHeight);
+	m_scope = originalScope;
+}
+
+AbstractAssembly::LabelID CodeTransform::labelFromIdentifier(Identifier const& _identifier)
+{
+	AbstractAssembly::LabelID label = AbstractAssembly::LabelID(-1);
+	if (!m_scope->lookup(_identifier.name, Scope::NonconstVisitor(
+		[=](Scope::Variable&) { solAssert(false, "Expected label"); },
+		[&](Scope::Label& _label)
+		{
+			label = labelID(_label);
+		},
+		[=](Scope::Function&) { solAssert(false, "Expected label"); }
+	)))
+	{
+		solAssert(false, "Identifier not found.");
+	}
+	return label;
+}
+
+AbstractAssembly::LabelID CodeTransform::labelID(Scope::Label const& _label)
+{
+	if (!m_context->labelIDs.count(&_label))
+		m_context->labelIDs[&_label] = m_assembly.newLabelId();
+	return m_context->labelIDs[&_label];
+}
+
+AbstractAssembly::LabelID CodeTransform::functionEntryID(string const& _name, Scope::Function const& _function)
+{
+	if (!m_context->functionEntryIDs.count(&_function))
+	{
+		AbstractAssembly::LabelID id =
+			m_useNamedLabelsForFunctions ?
+			m_assembly.namedLabel(_name) :
+			m_assembly.newLabelId();
+		m_context->functionEntryIDs[&_function] = id;
+	}
+	return m_context->functionEntryIDs[&_function];
+}
+
+void CodeTransform::visitExpression(Expression const& _expression)
+{
+	int height = m_assembly.stackHeight();
+	boost::apply_visitor(*this, _expression);
+	expectDeposit(1, height);
+}
+
+void CodeTransform::visitStatements(vector<Statement> const& _statements)
+{
+	for (auto const& statement: _statements)
+		boost::apply_visitor(*this, statement);
+}
+
+void CodeTransform::finalizeBlock(Block const& _block, int blockStartStackHeight)
+{
+	m_assembly.setSourceLocation(_block.location);
+
+	// pop variables
+	solAssert(m_info.scopes.at(&_block).get() == m_scope, "");
+	for (size_t i = 0; i < m_scope->numberOfVariables(); ++i)
+		m_assembly.appendInstruction(solidity::Instruction::POP);
+
+	int deposit = m_assembly.stackHeight() - blockStartStackHeight;
+	solAssert(deposit == 0, "Invalid stack height at end of block.");
+	checkStackHeight(&_block);
+}
+
+void CodeTransform::generateMultiAssignment(vector<Identifier> const& _variableNames)
+{
+	solAssert(m_scope, "");
+	for (auto const& variableName: _variableNames | boost::adaptors::reversed)
+		generateAssignment(variableName);
+}
+
+void CodeTransform::generateAssignment(Identifier const& _variableName)
+{
+	solAssert(m_scope, "");
+	auto var = m_scope->lookup(_variableName.name);
+	if (var)
+	{
+		Scope::Variable const& _var = boost::get<Scope::Variable>(*var);
+		if (int heightDiff = variableHeightDiff(_var, true))
+			m_assembly.appendInstruction(solidity::swapInstruction(heightDiff - 1));
+		m_assembly.appendInstruction(solidity::Instruction::POP);
+	}
+	else
+	{
+		solAssert(
+			m_identifierAccess.generateCode,
+			"Identifier not found and no external access available."
+		);
+		m_identifierAccess.generateCode(_variableName, IdentifierContext::LValue, m_assembly);
+	}
+}
+
+int CodeTransform::variableHeightDiff(solidity::assembly::Scope::Variable const& _var, bool _forSwap) const
+{
+	solAssert(m_context->variableStackHeights.count(&_var), "");
+	int heightDiff = m_assembly.stackHeight() - m_context->variableStackHeights[&_var];
+	if (heightDiff <= (_forSwap ? 1 : 0) || heightDiff > (_forSwap ? 17 : 16))
+	{
+		solUnimplemented(
+			"Variable inaccessible, too deep inside stack (" + to_string(heightDiff) + ")"
+		);
+		return 0;
+	}
+	else
+		return heightDiff;
+}
+
+void CodeTransform::expectDeposit(int _deposit, int _oldHeight) const
+{
+	solAssert(m_assembly.stackHeight() == _oldHeight + _deposit, "Invalid stack deposit.");
+}
+
+void CodeTransform::checkStackHeight(void const* _astElement) const
+{
+	solAssert(m_info.stackHeightInfo.count(_astElement), "Stack height for AST element not found.");
+	int stackHeightInAnalysis = m_info.stackHeightInfo.at(_astElement);
+	int stackHeightInCodegen = m_assembly.stackHeight() - m_stackAdjustment;
+	solAssert(
+		stackHeightInAnalysis == stackHeightInCodegen,
+		"Stack height mismatch between analysis and code generation phase: Analysis: " +
+		to_string(stackHeightInAnalysis) +
+		" code gen: " +
+		to_string(stackHeightInCodegen)
+	);
+}
diff --git a/libyul/backends/evm/EVMCodeTransform.h b/libyul/backends/evm/EVMCodeTransform.h
new file mode 100644
index 00000000..6a0941b6
--- /dev/null
+++ b/libyul/backends/evm/EVMCodeTransform.h
@@ -0,0 +1,158 @@
+/*
+	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/>.
+*/
+/**
+ * Common code generator for translating Yul / inline assembly to EVM and EVM1.5.
+ */
+
+#include <libyul/backends/evm/EVMAssembly.h>
+
+#include <libyul/ASTDataForward.h>
+
+#include <libsolidity/inlineasm/AsmScope.h>
+
+#include <boost/variant.hpp>
+#include <boost/optional.hpp>
+
+namespace dev
+{
+namespace solidity
+{
+class ErrorReporter;
+namespace assembly
+{
+struct AsmAnalysisInfo;
+}
+}
+namespace julia
+{
+class EVMAssembly;
+
+class CodeTransform: public boost::static_visitor<>
+{
+public:
+	/// Create the code transformer.
+	/// @param _identifierAccess used to resolve identifiers external to the inline assembly
+	CodeTransform(
+		julia::AbstractAssembly& _assembly,
+		solidity::assembly::AsmAnalysisInfo& _analysisInfo,
+		bool _yul = false,
+		bool _evm15 = false,
+		ExternalIdentifierAccess const& _identifierAccess = ExternalIdentifierAccess(),
+		bool _useNamedLabelsForFunctions = false
+	): CodeTransform(
+		_assembly,
+		_analysisInfo,
+		_yul,
+		_evm15,
+		_identifierAccess,
+		_useNamedLabelsForFunctions,
+		_assembly.stackHeight(),
+		std::make_shared<Context>()
+	)
+	{
+	}
+
+protected:
+	struct Context
+	{
+		using Scope = solidity::assembly::Scope;
+		std::map<Scope::Label const*, AbstractAssembly::LabelID> labelIDs;
+		std::map<Scope::Function const*, AbstractAssembly::LabelID> functionEntryIDs;
+		std::map<Scope::Variable const*, int> variableStackHeights;
+	};
+
+	CodeTransform(
+		julia::AbstractAssembly& _assembly,
+		solidity::assembly::AsmAnalysisInfo& _analysisInfo,
+		bool _yul,
+		bool _evm15,
+		ExternalIdentifierAccess const& _identifierAccess,
+		bool _useNamedLabelsForFunctions,
+		int _stackAdjustment,
+		std::shared_ptr<Context> _context
+	):
+		m_assembly(_assembly),
+		m_info(_analysisInfo),
+		m_yul(_yul),
+		m_evm15(_evm15),
+		m_useNamedLabelsForFunctions(_useNamedLabelsForFunctions),
+		m_identifierAccess(_identifierAccess),
+		m_stackAdjustment(_stackAdjustment),
+		m_context(_context)
+	{}
+
+public:
+	void operator()(Instruction const& _instruction);
+	void operator()(Literal const& _literal);
+	void operator()(Identifier const& _identifier);
+	void operator()(FunctionalInstruction const& _instr);
+	void operator()(FunctionCall const&);
+	void operator()(ExpressionStatement const& _statement);
+	void operator()(Label const& _label);
+	void operator()(StackAssignment const& _assignment);
+	void operator()(Assignment const& _assignment);
+	void operator()(VariableDeclaration const& _varDecl);
+	void operator()(If const& _if);
+	void operator()(Switch const& _switch);
+	void operator()(FunctionDefinition const&);
+	void operator()(ForLoop const&);
+	void operator()(Block const& _block);
+
+private:
+	AbstractAssembly::LabelID labelFromIdentifier(Identifier const& _identifier);
+	/// @returns the label ID corresponding to the given label, allocating a new one if
+	/// necessary.
+	AbstractAssembly::LabelID labelID(solidity::assembly::Scope::Label const& _label);
+	AbstractAssembly::LabelID functionEntryID(std::string const& _name, solidity::assembly::Scope::Function const& _function);
+	/// Generates code for an expression that is supposed to return a single value.
+	void visitExpression(Expression const& _expression);
+
+	void visitStatements(std::vector<Statement> const& _statements);
+
+	/// Pops all variables declared in the block and checks that the stack height is equal
+	/// to @a _blackStartStackHeight.
+	void finalizeBlock(Block const& _block, int _blockStartStackHeight);
+
+	void generateMultiAssignment(std::vector<Identifier> const& _variableNames);
+	void generateAssignment(Identifier const& _variableName);
+
+	/// Determines the stack height difference to the given variables. Throws
+	/// if it is not yet in scope or the height difference is too large. Returns
+	/// the (positive) stack height difference otherwise.
+	int variableHeightDiff(solidity::assembly::Scope::Variable const& _var, bool _forSwap) const;
+
+	void expectDeposit(int _deposit, int _oldHeight) const;
+
+	void checkStackHeight(void const* _astElement) const;
+
+	julia::AbstractAssembly& m_assembly;
+	solidity::assembly::AsmAnalysisInfo& m_info;
+	solidity::assembly::Scope* m_scope = nullptr;
+	bool m_yul = false;
+	bool m_evm15 = false;
+	bool 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
+	/// for inline assembly and different stack heights depending on the EVM backend used
+	/// (EVM 1.0 or 1.5).
+	int m_stackAdjustment = 0;
+	std::shared_ptr<Context> m_context;
+};
+
+}
+}