96 lines
3.5 KiB
C++
96 lines
3.5 KiB
C++
/*
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* Cppcheck - A tool for static C/C++ code analysis
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* Copyright (C) 2007-2022 Cppcheck team.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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//---------------------------------------------------------------------------
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#ifndef fwdanalysisH
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#define fwdanalysisH
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//---------------------------------------------------------------------------
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#include "config.h"
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#include <set>
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#include <vector>
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class Token;
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class Library;
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/**
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* Forward data flow analysis for checks
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* - unused value
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* - redundant assignment
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* - valueflow analysis
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*/
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class FwdAnalysis {
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public:
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FwdAnalysis(bool cpp, const Library &library) : mCpp(cpp), mLibrary(library), mWhat(What::Reassign), mValueFlowKnown(true) {}
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bool hasOperand(const Token *tok, const Token *lhs) const;
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/**
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* Check if "expr" is reassigned. The "expr" can be a tree (x.y[12]).
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* @param expr Symbolic expression to perform forward analysis for
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* @param startToken First token in forward analysis
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* @param endToken Last token in forward analysis
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* @return Token where expr is reassigned. If it's not reassigned then nullptr is returned.
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*/
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const Token *reassign(const Token *expr, const Token *startToken, const Token *endToken);
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/**
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* Check if "expr" is used. The "expr" can be a tree (x.y[12]).
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* @param expr Symbolic expression to perform forward analysis for
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* @param startToken First token in forward analysis
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* @param endToken Last token in forward analysis
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* @return true if expr is used.
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*/
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bool unusedValue(const Token *expr, const Token *startToken, const Token *endToken);
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struct KnownAndToken {
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bool known;
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const Token *token;
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};
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/** Is there some possible alias for given expression */
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bool possiblyAliased(const Token *expr, const Token *startToken) const;
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std::set<nonneg int> getExprVarIds(const Token* expr, bool* localOut = nullptr, bool* unknownVarIdOut = nullptr) const;
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private:
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static bool isEscapedAlias(const Token* expr);
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/** Result of forward analysis */
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struct Result {
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enum class Type { NONE, READ, WRITE, BREAK, RETURN, BAILOUT } type;
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explicit Result(Type type) : type(type), token(nullptr) {}
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Result(Type type, const Token *token) : type(type), token(token) {}
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const Token *token;
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};
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struct Result check(const Token *expr, const Token *startToken, const Token *endToken);
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struct Result checkRecursive(const Token *expr, const Token *startToken, const Token *endToken, const std::set<nonneg int> &exprVarIds, bool local, bool inInnerClass, int depth=0);
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// Is expression a l-value global data?
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bool isGlobalData(const Token *expr) const;
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const bool mCpp;
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const Library &mLibrary;
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enum class What { Reassign, UnusedValue, ValueFlow } mWhat;
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std::vector<KnownAndToken> mValueFlow;
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bool mValueFlowKnown;
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};
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#endif // fwdanalysisH
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