solidity/libevmasm/AssemblyItem.h
2021-10-12 17:56:17 +02:00

215 lines
8.2 KiB
C++

/*
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/>.
*/
// SPDX-License-Identifier: GPL-3.0
/** @file AssemblyItem.h
* @author Gav Wood <i@gavwood.com>
* @date 2014
*/
#pragma once
#include <libevmasm/Instruction.h>
#include <libevmasm/Exceptions.h>
#include <liblangutil/SourceLocation.h>
#include <libsolutil/Common.h>
#include <libsolutil/Assertions.h>
#include <optional>
#include <iostream>
#include <sstream>
namespace solidity::evmasm
{
enum AssemblyItemType
{
UndefinedItem,
Operation,
Push,
PushTag,
PushSub,
PushSubSize,
PushProgramSize,
Tag,
PushData,
PushLibraryAddress, ///< Push a currently unknown address of another (library) contract.
PushDeployTimeAddress, ///< Push an address to be filled at deploy time. Should not be touched by the optimizer.
PushImmutable, ///< Push the currently unknown value of an immutable variable. The actual value will be filled in by the constructor.
AssignImmutable, ///< Assigns the current value on the stack to an immutable variable. Only valid during creation code.
VerbatimBytecode ///< Contains data that is inserted into the bytecode code section without modification.
};
enum class Precision { Precise , Approximate };
class Assembly;
class AssemblyItem;
using AssemblyItems = std::vector<AssemblyItem>;
class AssemblyItem
{
public:
enum class JumpType { Ordinary, IntoFunction, OutOfFunction };
AssemblyItem(u256 _push, langutil::SourceLocation _location = langutil::SourceLocation()):
AssemblyItem(Push, std::move(_push), std::move(_location)) { }
AssemblyItem(Instruction _i, langutil::SourceLocation _location = langutil::SourceLocation()):
m_type(Operation),
m_instruction(_i),
m_location(std::move(_location))
{}
AssemblyItem(AssemblyItemType _type, u256 _data = 0, langutil::SourceLocation _location = langutil::SourceLocation()):
m_type(_type),
m_location(std::move(_location))
{
if (m_type == Operation)
m_instruction = Instruction(uint8_t(_data));
else
m_data = std::make_shared<u256>(std::move(_data));
}
explicit AssemblyItem(bytes _verbatimData, size_t _arguments, size_t _returnVariables):
m_type(VerbatimBytecode),
m_instruction{},
m_verbatimBytecode{{_arguments, _returnVariables, std::move(_verbatimData)}}
{}
AssemblyItem(AssemblyItem const&) = default;
AssemblyItem(AssemblyItem&&) = default;
AssemblyItem& operator=(AssemblyItem const&) = default;
AssemblyItem& operator=(AssemblyItem&&) = default;
AssemblyItem tag() const { assertThrow(m_type == PushTag || m_type == Tag, util::Exception, ""); return AssemblyItem(Tag, data()); }
AssemblyItem pushTag() const { assertThrow(m_type == PushTag || m_type == Tag, util::Exception, ""); return AssemblyItem(PushTag, data()); }
/// Converts the tag to a subassembly tag. This has to be called in order to move a tag across assemblies.
/// @param _subId the identifier of the subassembly the tag is taken from.
AssemblyItem toSubAssemblyTag(size_t _subId) const;
/// @returns splits the data of the push tag into sub assembly id and actual tag id.
/// The sub assembly id of non-foreign push tags is -1.
std::pair<size_t, size_t> splitForeignPushTag() const;
/// Sets sub-assembly part and tag for a push tag.
void setPushTagSubIdAndTag(size_t _subId, size_t _tag);
AssemblyItemType type() const { return m_type; }
u256 const& data() const { assertThrow(m_type != Operation, util::Exception, ""); return *m_data; }
void setData(u256 const& _data) { assertThrow(m_type != Operation, util::Exception, ""); m_data = std::make_shared<u256>(_data); }
bytes const& verbatimData() const { assertThrow(m_type == VerbatimBytecode, util::Exception, ""); return std::get<2>(*m_verbatimBytecode); }
/// @returns the instruction of this item (only valid if type() == Operation)
Instruction instruction() const { assertThrow(m_type == Operation, util::Exception, ""); return m_instruction; }
/// @returns true if the type and data of the items are equal.
bool operator==(AssemblyItem const& _other) const
{
if (type() != _other.type())
return false;
if (type() == Operation)
return instruction() == _other.instruction();
else if (type() == VerbatimBytecode)
return *m_verbatimBytecode == *_other.m_verbatimBytecode;
else
return data() == _other.data();
}
bool operator!=(AssemblyItem const& _other) const { return !operator==(_other); }
/// Less-than operator compatible with operator==.
bool operator<(AssemblyItem const& _other) const
{
if (type() != _other.type())
return type() < _other.type();
else if (type() == Operation)
return instruction() < _other.instruction();
else if (type() == VerbatimBytecode)
return *m_verbatimBytecode == *_other.m_verbatimBytecode;
else
return data() < _other.data();
}
/// Shortcut that avoids constructing an AssemblyItem just to perform the comparison.
bool operator==(Instruction _instr) const
{
return type() == Operation && instruction() == _instr;
}
bool operator!=(Instruction _instr) const { return !operator==(_instr); }
static std::string computeSourceMapping(
AssemblyItems const& _items,
std::map<std::string, unsigned> const& _sourceIndicesMap
);
/// @returns an upper bound for the number of bytes required by this item, assuming that
/// the value of a jump tag takes @a _addressLength bytes.
/// @param _precision Whether to return a precise count (which involves
/// counting immutable references which are only set after
/// a call to `assemble()`) or an approx. count.
size_t bytesRequired(size_t _addressLength, Precision _precision = Precision::Precise) const;
size_t arguments() const;
size_t returnValues() const;
size_t deposit() const { return returnValues() - arguments(); }
/// @returns true if the assembly item can be used in a functional context.
bool canBeFunctional() const;
void setLocation(langutil::SourceLocation const& _location) { m_location = _location; }
langutil::SourceLocation const& location() const { return m_location; }
void setJumpType(JumpType _jumpType) { m_jumpType = _jumpType; }
JumpType getJumpType() const { return m_jumpType; }
std::string getJumpTypeAsString() const;
void setPushedValue(u256 const& _value) const { m_pushedValue = std::make_shared<u256>(_value); }
u256 const* pushedValue() const { return m_pushedValue.get(); }
std::string toAssemblyText(Assembly const& _assembly) const;
size_t m_modifierDepth = 0;
void setImmutableOccurrences(size_t _n) const { m_immutableOccurrences = _n; }
private:
size_t opcodeCount() const noexcept;
AssemblyItemType m_type;
Instruction m_instruction; ///< Only valid if m_type == Operation
std::shared_ptr<u256> m_data; ///< Only valid if m_type != Operation
/// If m_type == VerbatimBytecode, this holds number of arguments, number of
/// return variables and verbatim bytecode.
std::optional<std::tuple<size_t, size_t, bytes>> m_verbatimBytecode;
langutil::SourceLocation m_location;
JumpType m_jumpType = JumpType::Ordinary;
/// Pushed value for operations with data to be determined during assembly stage,
/// e.g. PushSubSize, PushTag, PushSub, etc.
mutable std::shared_ptr<u256> m_pushedValue;
/// Number of PushImmutable's with the same hash. Only used for AssignImmutable.
mutable std::optional<size_t> m_immutableOccurrences;
};
inline size_t bytesRequired(AssemblyItems const& _items, size_t _addressLength, Precision _precision = Precision::Precise)
{
size_t size = 0;
for (AssemblyItem const& item: _items)
size += item.bytesRequired(_addressLength, _precision);
return size;
}
std::ostream& operator<<(std::ostream& _out, AssemblyItem const& _item);
inline std::ostream& operator<<(std::ostream& _out, AssemblyItems const& _items)
{
for (AssemblyItem const& item: _items)
_out << item;
return _out;
}
}