solidity/libsolidity/codegen/ir/IRLValue.cpp

/*
	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/>.
*/
/**
 * Generator for code that handles LValues.
 */

#include <libsolidity/codegen/ir/IRLValue.h>

#include <libsolidity/codegen/ir/IRGenerationContext.h>
#include <libsolidity/codegen/YulUtilFunctions.h>
#include <libsolidity/codegen/CompilerUtils.h>
#include <libsolidity/ast/AST.h>

#include <libdevcore/Whiskers.h>

using namespace std;
using namespace dev;
using namespace dev::solidity;

IRLocalVariable::IRLocalVariable(
	IRGenerationContext& _context,
	VariableDeclaration const& _varDecl
):
	IRLValue(_context, _varDecl.annotation().type),
	m_variableName(_context.localVariableName(_varDecl))
{
}

string IRLocalVariable::storeValue(string const& _value, Type const& _type) const
{
	solAssert(_type == *m_type, "Storing different types - not necessarily a problem.");
	return m_variableName + " := " + _value + "\n";
}

string IRLocalVariable::setToZero() const
{
	return storeValue(m_context.utils().zeroValueFunction(*m_type) + "()", *m_type);
}

IRStorageItem::IRStorageItem(
	IRGenerationContext& _context,
	VariableDeclaration const& _varDecl
):
	IRStorageItem(
	_context,
	*_varDecl.annotation().type,
	_context.storageLocationOfVariable(_varDecl)
)
{ }

IRStorageItem::IRStorageItem(
	IRGenerationContext& _context,
	Type const& _type,
	std::pair<u256, unsigned> slot_offset
):
	IRLValue(_context, &_type),
	m_slot(toCompactHexWithPrefix(slot_offset.first)),
	m_offset(slot_offset.second)
{
}

IRStorageItem::IRStorageItem(
	IRGenerationContext& _context,
	string _slot,
	boost::variant<string, unsigned> _offset,
	Type const& _type
):
	IRLValue(_context, &_type),
	m_slot(move(_slot)),
	m_offset(std::move(_offset))
{
	solAssert(!m_offset.empty(), "");
	solAssert(!m_slot.empty(), "");
}

string IRStorageItem::retrieveValue() const
{
	if (!m_type->isValueType())
		return m_slot;
	solUnimplementedAssert(m_type->category() != Type::Category::Function, "");
	if (m_offset.type() == typeid(string))
		return
			m_context.utils().readFromStorageDynamic(*m_type, false) +
			"(" +
			m_slot +
			", " +
			boost::get<string>(m_offset) +
			")";
	else if (m_offset.type() == typeid(unsigned))
		return
			m_context.utils().readFromStorage(*m_type, boost::get<unsigned>(m_offset), false) +
			"(" +
			m_slot +
			")";

	solAssert(false, "");
}

string IRStorageItem::storeValue(string const& _value, Type const& _sourceType) const
{
	if (m_type->isValueType())
		solAssert(_sourceType == *m_type, "Different type, but might not be an error.");

	boost::optional<unsigned> offset;

	if (m_offset.type() == typeid(unsigned))
		offset = get<unsigned>(m_offset);

	return
		m_context.utils().updateStorageValueFunction(*m_type, offset) +
		"(" +
		m_slot +
		(m_offset.type() == typeid(string) ?
			(", " + get<string>(m_offset)) :
			""
		) +
		", " +
		_value +
		")\n";
}

string IRStorageItem::setToZero() const
{
	solUnimplementedAssert(m_type->isValueType(), "");
	return storeValue(m_context.utils().zeroValueFunction(*m_type) + "()", *m_type);
}

IRStorageArrayLength::IRStorageArrayLength(IRGenerationContext& _context, string _slot, Type const& _type, ArrayType const& _arrayType):
	IRLValue(_context, &_type), m_arrayType(_arrayType), m_slot(move(_slot))
{
	solAssert(*m_type == *TypeProvider::uint256(), "Must be uint256!");
}

string IRStorageArrayLength::retrieveValue() const
{
	return m_context.utils().arrayLengthFunction(m_arrayType) + "(" + m_slot + ")";
}

string IRStorageArrayLength::storeValue(std::string const& _value, Type const& _type) const
{
	solAssert(_type == *m_type, "Different type, but might not be an error.");

	return m_context.utils().resizeDynamicArrayFunction(m_arrayType) +
		"(" +
		m_slot +
		", " +
		_value +
		")\n";
}

string IRStorageArrayLength::setToZero() const
{
	return storeValue("0", *TypeProvider::uint256());
}

IRMemoryItem::IRMemoryItem(
	IRGenerationContext& _context,
	std::string _address,
	bool _byteArrayElement,
	Type const& _type
):
	IRLValue(_context, &_type),
	m_address(move(_address)),
	m_byteArrayElement(_byteArrayElement)
{ }

string IRMemoryItem::retrieveValue() const
{
	if (m_byteArrayElement)
		return m_context.utils().cleanupFunction(*m_type) +
			"(mload(" +
			m_address +
			"))";

	if (m_type->isValueType())
		return m_context.utils().readFromMemory(*m_type) +
			"(" +
			m_address +
			")";
	else
		return "mload(" + m_address + ")";
}

string IRMemoryItem::storeValue(string const& _value, Type const& _type) const
{
	if (!m_type->isValueType())
	{
		solUnimplementedAssert(_type == *m_type, "Conversion not implemented for assignment to memory.");

		solAssert(m_type->sizeOnStack() == 1, "");
		solAssert(dynamic_cast<ReferenceType const*>(m_type), "");

		return "mstore(" + m_address + ", " + _value + ")\n";
	}

	solAssert(_type.isValueType(), "");

	string prepared = _value;

	// Exists to see if this case ever happens
	solAssert(_type == *m_type, "");

	if (_type != *m_type)
		prepared =
			m_context.utils().conversionFunction(_type, *m_type) +
			"(" +
			_value +
			")";
	else
		prepared =
			m_context.utils().cleanupFunction(*m_type) +
			"(" +
			_value +
			")";

	if (m_byteArrayElement)
	{
		solAssert(*m_type == *TypeProvider::byte(), "");
		return "mstore8(" + m_address + ", byte(0, " + prepared + "))\n";
	}
	else
		return m_context.utils().writeToMemoryFunction(*m_type) +
			"(" +
			m_address +
			", " +
			prepared +
			")\n";
}

string IRMemoryItem::setToZero() const
{
	return storeValue(m_context.utils().zeroValueFunction(*m_type) + "()", *m_type);
}