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/* -*- C++ -*-
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2024 Cppcheck team.
*
* This program 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.
*
* This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*/
//---------------------------------------------------------------------------
#ifndef fwdanalysisH
#define fwdanalysisH
//---------------------------------------------------------------------------
#include "config.h"
#include <cstdint>
#include <set>
#include <vector>
class Token;
class Settings;
/**
* Forward data flow analysis for checks
* - unused value
* - redundant assignment
* - valueflow analysis
*/
class FwdAnalysis {
public:
explicit FwdAnalysis(const Settings &settings) : mSettings(settings) {}
bool hasOperand(const Token *tok, const Token *lhs) const;
/**
* Check if "expr" is reassigned. The "expr" can be a tree (x.y[12]).
* @param expr Symbolic expression to perform forward analysis for
* @param startToken First token in forward analysis
* @param endToken Last token in forward analysis
* @return Token where expr is reassigned. If it's not reassigned then nullptr is returned.
*/
const Token *reassign(const Token *expr, const Token *startToken, const Token *endToken);
/**
* Check if "expr" is used. The "expr" can be a tree (x.y[12]).
* @param expr Symbolic expression to perform forward analysis for
* @param startToken First token in forward analysis
* @param endToken Last token in forward analysis
* @return true if expr is used.
*/
bool unusedValue(const Token *expr, const Token *startToken, const Token *endToken);
struct KnownAndToken {
bool known{};
const Token* token{};
};
/** Is there some possible alias for given expression */
bool possiblyAliased(const Token *expr, const Token *startToken) const;
std::set<nonneg int> getExprVarIds(const Token* expr, bool* localOut = nullptr, bool* unknownVarIdOut = nullptr) const;
private:
static bool isEscapedAlias(const Token* expr);
/** Result of forward analysis */
struct Result {
enum class Type : std::uint8_t { NONE, READ, WRITE, BREAK, RETURN, BAILOUT } type;
explicit Result(Type type) : type(type) {}
Result(Type type, const Token *token) : type(type), token(token) {}
const Token* token{};
};
Result check(const Token *expr, const Token *startToken, const Token *endToken);
Result checkRecursive(const Token *expr, const Token *startToken, const Token *endToken, const std::set<nonneg int> &exprVarIds, bool local, bool inInnerClass, int depth=0);
const Settings &mSettings;
enum class What : std::uint8_t { Reassign, UnusedValue, ValueFlow } mWhat = What::Reassign;
std::vector<KnownAndToken> mValueFlow;
bool mValueFlowKnown = true;
};
#endif // fwdanalysisH
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