File: fwdanalysis.h

package info (click to toggle)
cppcheck 2.17.1-2
  • links: PTS, VCS
  • area: main
  • in suites: sid, trixie
  • size: 25,384 kB
  • sloc: cpp: 263,341; python: 19,737; ansic: 7,953; sh: 1,018; makefile: 996; xml: 994; cs: 291
file content (92 lines) | stat: -rw-r--r-- 3,429 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
/* -*- 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