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/*
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/>.
*/
/**
* Module for applying replacement rules against Expressions.
*/
#pragma once
#include <libevmasm/ExpressionClasses.h>
#include <libevmasm/SimplificationRule.h>
#include <libyul/ASTDataForward.h>
#include <libsolidity/inlineasm/AsmData.h>
#include <boost/noncopyable.hpp>
#include <functional>
#include <vector>
namespace dev
{
namespace yul
{
class Pattern;
/**
* Container for all simplification rules.
*/
class SimplificationRules: public boost::noncopyable
{
public:
SimplificationRules();
/// @returns a pointer to the first matching pattern and sets the match
/// groups accordingly.
/// @param _ssaValues values of variables that are assigned exactly once.
static SimplificationRule<Pattern> const* findFirstMatch(
Expression const& _expr,
std::map<YulString, Expression const*> const& _ssaValues
);
/// Checks whether the rulelist is non-empty. This is usually enforced
/// by the constructor, but we had some issues with static initialization.
bool isInitialized() const;
private:
void addRules(std::vector<SimplificationRule<Pattern>> const& _rules);
void addRule(SimplificationRule<Pattern> const& _rule);
void resetMatchGroups() { m_matchGroups.clear(); }
std::map<unsigned, Expression const*> m_matchGroups;
std::vector<SimplificationRule<Pattern>> m_rules[256];
};
enum class PatternKind
{
Operation,
Constant,
Any
};
/**
* Pattern to match against an expression.
* Also stores matched expressions to retrieve them later, for constructing new expressions using
* ExpressionTemplate.
*/
class Pattern
{
public:
/// Matches any expression.
Pattern(PatternKind _kind = PatternKind::Any): m_kind(_kind) {}
// Matches a specific constant value.
Pattern(unsigned _value): Pattern(u256(_value)) {}
// Matches a specific constant value.
Pattern(u256 const& _value): m_kind(PatternKind::Constant), m_data(std::make_shared<u256>(_value)) {}
// Matches a given instruction with given arguments
Pattern(solidity::Instruction _instruction, std::vector<Pattern> const& _arguments = {});
/// Sets this pattern to be part of the match group with the identifier @a _group.
/// Inside one rule, all patterns in the same match group have to match expressions from the
/// same expression equivalence class.
void setMatchGroup(unsigned _group, std::map<unsigned, Expression const*>& _matchGroups);
unsigned matchGroup() const { return m_matchGroup; }
bool matches(Expression const& _expr, std::map<YulString, Expression const*> const& _ssaValues) const;
std::vector<Pattern> arguments() const { return m_arguments; }
/// @returns the data of the matched expression if this pattern is part of a match group.
u256 d() const;
solidity::Instruction instruction() const;
/// Turns this pattern into an actual expression. Should only be called
/// for patterns resulting from an action, i.e. with match groups assigned.
Expression toExpression(SourceLocation const& _location) const;
private:
Expression const& matchGroupValue() const;
PatternKind m_kind = PatternKind::Any;
solidity::Instruction m_instruction; ///< Only valid if m_kind is Operation
std::shared_ptr<u256> m_data; ///< Only valid if m_kind is Constant
std::vector<Pattern> m_arguments;
unsigned m_matchGroup = 0;
std::map<unsigned, Expression const*>* m_matchGroups = nullptr;
};
}
}
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