2041 lines
88 KiB
C++
2041 lines
88 KiB
C++
/*
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* Cppcheck - A tool for static C/C++ code analysis
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* Copyright (C) 2007-2023 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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// Check for condition mismatches
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//---------------------------------------------------------------------------
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#include "checkcondition.h"
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#include "astutils.h"
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#include "library.h"
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#include "platform.h"
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#include "settings.h"
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#include "symboldatabase.h"
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#include "token.h"
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#include "tokenize.h"
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#include "utils.h"
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#include "vfvalue.h"
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#include "checkother.h" // comparisonNonZeroExpressionLessThanZero and testIfNonZeroExpressionIsPositive
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#include <algorithm>
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#include <limits>
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#include <list>
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#include <set>
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#include <sstream>
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#include <utility>
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#include <vector>
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// CWE ids used
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static const CWE uncheckedErrorConditionCWE(391U);
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static const CWE CWE398(398U); // Indicator of Poor Code Quality
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static const CWE CWE570(570U); // Expression is Always False
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static const CWE CWE571(571U); // Expression is Always True
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//---------------------------------------------------------------------------
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// Register this check class (by creating a static instance of it)
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namespace {
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CheckCondition instance;
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}
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bool CheckCondition::diag(const Token* tok, bool insert)
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{
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if (!tok)
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return false;
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const Token* parent = tok->astParent();
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bool hasParent = false;
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while (Token::Match(parent, "!|&&|%oror%")) {
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if (mCondDiags.count(parent) != 0) {
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hasParent = true;
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break;
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}
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parent = parent->astParent();
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}
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if (mCondDiags.count(tok) == 0 && !hasParent) {
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if (insert)
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mCondDiags.insert(tok);
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return false;
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}
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return true;
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}
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bool CheckCondition::isAliased(const std::set<int> &vars) const
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{
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for (const Token *tok = mTokenizer->tokens(); tok; tok = tok->next()) {
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if (Token::Match(tok, "= & %var% ;") && vars.find(tok->tokAt(2)->varId()) != vars.end())
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return true;
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}
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return false;
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}
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void CheckCondition::assignIf()
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{
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if (!mSettings->severity.isEnabled(Severity::style))
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return;
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logChecker("CheckCondition::assignIf"); // style
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for (const Token *tok = mTokenizer->tokens(); tok; tok = tok->next()) {
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if (tok->str() != "=")
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continue;
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if (Token::Match(tok->tokAt(-2), "[;{}] %var% =")) {
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const Variable *var = tok->previous()->variable();
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if (var == nullptr)
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continue;
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char bitop = '\0';
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MathLib::bigint num = 0;
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if (Token::Match(tok->next(), "%num% [&|]")) {
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bitop = tok->strAt(2).at(0);
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num = MathLib::toBigNumber(tok->next()->str());
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} else {
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const Token *endToken = Token::findsimplematch(tok, ";");
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// Casting address
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if (endToken && Token::Match(endToken->tokAt(-4), "* ) & %any% ;"))
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endToken = nullptr;
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if (endToken && Token::Match(endToken->tokAt(-2), "[&|] %num% ;")) {
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bitop = endToken->strAt(-2).at(0);
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num = MathLib::toBigNumber(endToken->previous()->str());
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}
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}
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if (bitop == '\0')
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continue;
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if (num < 0 && bitop == '|')
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continue;
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assignIfParseScope(tok, tok->tokAt(4), var->declarationId(), var->isLocal(), bitop, num);
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}
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}
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}
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static bool isParameterChanged(const Token *partok)
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{
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bool addressOf = Token::Match(partok, "[(,] &");
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int argumentNumber = 0;
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const Token *ftok;
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for (ftok = partok; ftok && ftok->str() != "("; ftok = ftok->previous()) {
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if (ftok->str() == ")")
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ftok = ftok->link();
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else if (argumentNumber == 0U && ftok->str() == "&")
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addressOf = true;
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else if (ftok->str() == ",")
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argumentNumber++;
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}
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ftok = ftok ? ftok->previous() : nullptr;
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if (!(ftok && ftok->function()))
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return true;
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const Variable *par = ftok->function()->getArgumentVar(argumentNumber);
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if (!par)
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return true;
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if (par->isConst())
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return false;
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if (addressOf || par->isReference() || par->isPointer())
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return true;
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return false;
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}
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/** parse scopes recursively */
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bool CheckCondition::assignIfParseScope(const Token * const assignTok,
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const Token * const startTok,
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const nonneg int varid,
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const bool islocal,
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const char bitop,
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const MathLib::bigint num)
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{
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bool ret = false;
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for (const Token *tok2 = startTok; tok2; tok2 = tok2->next()) {
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if ((bitop == '&') && Token::Match(tok2->tokAt(2), "%varid% %cop% %num% ;", varid) && tok2->strAt(3) == std::string(1U, bitop)) {
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const MathLib::bigint num2 = MathLib::toBigNumber(tok2->strAt(4));
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if (0 == (num & num2))
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mismatchingBitAndError(assignTok, num, tok2, num2);
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}
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if (Token::Match(tok2, "%varid% =", varid)) {
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return true;
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}
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if (bitop == '&' && Token::Match(tok2, "%varid% &= %num% ;", varid)) {
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const MathLib::bigint num2 = MathLib::toBigNumber(tok2->strAt(2));
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if (0 == (num & num2))
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mismatchingBitAndError(assignTok, num, tok2, num2);
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}
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if (Token::Match(tok2, "++|-- %varid%", varid) || Token::Match(tok2, "%varid% ++|--", varid))
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return true;
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if (Token::Match(tok2, "[(,] &| %varid% [,)]", varid) && isParameterChanged(tok2))
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return true;
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if (tok2->str() == "}")
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return false;
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if (Token::Match(tok2, "break|continue|return"))
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ret = true;
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if (ret && tok2->str() == ";")
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return false;
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if (!islocal && Token::Match(tok2, "%name% (") && !Token::simpleMatch(tok2->next()->link(), ") {"))
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return true;
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if (Token::Match(tok2, "if|while (")) {
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if (!islocal && tok2->str() == "while")
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continue;
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if (tok2->str() == "while") {
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// is variable changed in loop?
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const Token *bodyStart = tok2->linkAt(1)->next();
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const Token *bodyEnd = bodyStart ? bodyStart->link() : nullptr;
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if (!bodyEnd || bodyEnd->str() != "}" || isVariableChanged(bodyStart, bodyEnd, varid, !islocal, mSettings, mTokenizer->isCPP()))
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continue;
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}
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// parse condition
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const Token * const end = tok2->next()->link();
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for (; tok2 != end; tok2 = tok2->next()) {
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if (Token::Match(tok2, "[(,] &| %varid% [,)]", varid)) {
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return true;
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}
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if (Token::Match(tok2,"&&|%oror%|( %varid% ==|!= %num% &&|%oror%|)", varid)) {
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const Token *vartok = tok2->next();
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const MathLib::bigint num2 = MathLib::toBigNumber(vartok->strAt(2));
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if ((num & num2) != ((bitop=='&') ? num2 : num)) {
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const std::string& op(vartok->strAt(1));
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const bool alwaysTrue = op == "!=";
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const std::string condition(vartok->str() + op + vartok->strAt(2));
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assignIfError(assignTok, tok2, condition, alwaysTrue);
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}
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}
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if (Token::Match(tok2, "%varid% %op%", varid) && tok2->next()->isAssignmentOp()) {
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return true;
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}
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}
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const bool ret1 = assignIfParseScope(assignTok, end->tokAt(2), varid, islocal, bitop, num);
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bool ret2 = false;
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if (Token::simpleMatch(end->next()->link(), "} else {"))
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ret2 = assignIfParseScope(assignTok, end->next()->link()->tokAt(3), varid, islocal, bitop, num);
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if (ret1 || ret2)
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return true;
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}
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}
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return false;
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}
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void CheckCondition::assignIfError(const Token *tok1, const Token *tok2, const std::string &condition, bool result)
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{
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if (tok2 && diag(tok2->tokAt(2)))
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return;
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std::list<const Token *> locations = { tok1, tok2 };
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reportError(locations,
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Severity::style,
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"assignIfError",
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"Mismatching assignment and comparison, comparison '" + condition + "' is always " + std::string(bool_to_string(result)) + ".", CWE398, Certainty::normal);
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}
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void CheckCondition::mismatchingBitAndError(const Token *tok1, const MathLib::bigint num1, const Token *tok2, const MathLib::bigint num2)
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{
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std::list<const Token *> locations = { tok1, tok2 };
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std::ostringstream msg;
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msg << "Mismatching bitmasks. Result is always 0 ("
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<< "X = Y & 0x" << std::hex << num1 << "; Z = X & 0x" << std::hex << num2 << "; => Z=0).";
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reportError(locations,
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Severity::style,
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"mismatchingBitAnd",
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msg.str(), CWE398, Certainty::normal);
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}
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static void getnumchildren(const Token *tok, std::list<MathLib::bigint> &numchildren)
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{
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if (tok->astOperand1() && tok->astOperand1()->isNumber())
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numchildren.push_back(MathLib::toBigNumber(tok->astOperand1()->str()));
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else if (tok->astOperand1() && tok->str() == tok->astOperand1()->str())
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getnumchildren(tok->astOperand1(), numchildren);
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if (tok->astOperand2() && tok->astOperand2()->isNumber())
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numchildren.push_back(MathLib::toBigNumber(tok->astOperand2()->str()));
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else if (tok->astOperand2() && tok->str() == tok->astOperand2()->str())
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getnumchildren(tok->astOperand2(), numchildren);
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}
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/* Return whether tok is in the body for a function returning a boolean. */
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static bool inBooleanFunction(const Token *tok)
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{
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const Scope *scope = tok ? tok->scope() : nullptr;
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while (scope && scope->isLocal())
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scope = scope->nestedIn;
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if (scope && scope->type == Scope::eFunction) {
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const Function *func = scope->function;
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if (func) {
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const Token *ret = func->retDef;
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while (Token::Match(ret, "static|const"))
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ret = ret->next();
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return Token::Match(ret, "bool|_Bool");
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}
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}
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return false;
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}
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static bool isOperandExpanded(const Token *tok)
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{
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if (tok->isExpandedMacro() || tok->isEnumerator())
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return true;
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if (tok->astOperand1() && isOperandExpanded(tok->astOperand1()))
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return true;
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if (tok->astOperand2() && isOperandExpanded(tok->astOperand2()))
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return true;
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return false;
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}
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void CheckCondition::checkBadBitmaskCheck()
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{
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if (!mSettings->severity.isEnabled(Severity::style))
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return;
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logChecker("CheckCondition::checkBadBitmaskCheck"); // style
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for (const Token *tok = mTokenizer->tokens(); tok; tok = tok->next()) {
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if (tok->str() == "|" && tok->astOperand1() && tok->astOperand2() && tok->astParent()) {
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const Token* parent = tok->astParent();
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const bool isBoolean = Token::Match(parent, "&&|%oror%") ||
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(parent->str() == "?" && parent->astOperand1() == tok) ||
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(parent->str() == "=" && parent->astOperand2() == tok && parent->astOperand1() && parent->astOperand1()->variable() && Token::Match(parent->astOperand1()->variable()->typeStartToken(), "bool|_Bool")) ||
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(parent->str() == "(" && Token::Match(parent->astOperand1(), "if|while")) ||
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(parent->str() == "return" && parent->astOperand1() == tok && inBooleanFunction(tok));
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const bool isTrue = (tok->astOperand1()->hasKnownIntValue() && tok->astOperand1()->values().front().intvalue != 0) ||
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(tok->astOperand2()->hasKnownIntValue() && tok->astOperand2()->values().front().intvalue != 0);
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if (isBoolean && isTrue)
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badBitmaskCheckError(tok);
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// If there are #ifdef in the expression don't warn about redundant | to avoid FP
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const auto& startStop = tok->findExpressionStartEndTokens();
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if (mTokenizer->hasIfdef(startStop.first, startStop.second))
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continue;
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const bool isZero1 = (tok->astOperand1()->hasKnownIntValue() && tok->astOperand1()->values().front().intvalue == 0);
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const bool isZero2 = (tok->astOperand2()->hasKnownIntValue() && tok->astOperand2()->values().front().intvalue == 0);
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if (!isZero1 && !isZero2)
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continue;
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if (!tok->isExpandedMacro() &&
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!(isZero1 && isOperandExpanded(tok->astOperand1())) &&
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!(isZero2 && isOperandExpanded(tok->astOperand2())))
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badBitmaskCheckError(tok, /*isNoOp*/ true);
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}
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}
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}
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void CheckCondition::badBitmaskCheckError(const Token *tok, bool isNoOp)
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{
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if (isNoOp)
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reportError(tok, Severity::style, "badBitmaskCheck", "Operator '|' with one operand equal to zero is redundant.", CWE571, Certainty::normal);
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else
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reportError(tok, Severity::warning, "badBitmaskCheck", "Result of operator '|' is always true if one operand is non-zero. Did you intend to use '&'?", CWE571, Certainty::normal);
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}
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void CheckCondition::comparison()
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{
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if (!mSettings->severity.isEnabled(Severity::style))
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return;
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logChecker("CheckCondition::comparison"); // style
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for (const Token *tok = mTokenizer->tokens(); tok; tok = tok->next()) {
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if (!tok->isComparisonOp())
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continue;
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const Token *expr1 = tok->astOperand1();
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const Token *expr2 = tok->astOperand2();
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if (!expr1 || !expr2)
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continue;
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if (expr1->isNumber())
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std::swap(expr1,expr2);
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if (!expr2->isNumber())
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continue;
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const MathLib::bigint num2 = MathLib::toBigNumber(expr2->str());
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if (num2 < 0)
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continue;
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if (!Token::Match(expr1,"[&|]"))
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continue;
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std::list<MathLib::bigint> numbers;
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getnumchildren(expr1, numbers);
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for (const MathLib::bigint num1 : numbers) {
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if (num1 < 0)
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continue;
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if (Token::Match(tok, "==|!=")) {
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if ((expr1->str() == "&" && (num1 & num2) != num2) ||
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(expr1->str() == "|" && (num1 | num2) != num2)) {
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const std::string& op(tok->str());
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comparisonError(expr1, expr1->str(), num1, op, num2, op != "==");
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}
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} else if (expr1->str() == "&") {
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const bool or_equal = Token::Match(tok, ">=|<=");
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const std::string& op(tok->str());
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if ((Token::Match(tok, ">=|<")) && (num1 < num2)) {
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comparisonError(expr1, expr1->str(), num1, op, num2, !or_equal);
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} else if ((Token::Match(tok, "<=|>")) && (num1 <= num2)) {
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comparisonError(expr1, expr1->str(), num1, op, num2, or_equal);
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}
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} else if (expr1->str() == "|") {
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if ((expr1->astOperand1()->valueType()) &&
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(expr1->astOperand1()->valueType()->sign == ValueType::Sign::UNSIGNED)) {
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const bool or_equal = Token::Match(tok, ">=|<=");
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const std::string& op(tok->str());
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if ((Token::Match(tok, ">=|<")) && (num1 >= num2)) {
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//"(a | 0x07) >= 7U" is always true for unsigned a
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//"(a | 0x07) < 7U" is always false for unsigned a
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comparisonError(expr1, expr1->str(), num1, op, num2, or_equal);
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} else if ((Token::Match(tok, "<=|>")) && (num1 > num2)) {
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//"(a | 0x08) <= 7U" is always false for unsigned a
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//"(a | 0x07) > 6U" is always true for unsigned a
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comparisonError(expr1, expr1->str(), num1, op, num2, !or_equal);
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}
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}
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}
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}
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}
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}
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void CheckCondition::comparisonError(const Token *tok, const std::string &bitop, MathLib::bigint value1, const std::string &op, MathLib::bigint value2, bool result)
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{
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if (tok && (diag(tok) | diag(tok->astParent())))
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return;
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std::ostringstream expression;
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expression << std::hex << "(X " << bitop << " 0x" << value1 << ") " << op << " 0x" << value2;
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const std::string errmsg("Expression '" + expression.str() + "' is always " + bool_to_string(result) + ".\n"
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"The expression '" + expression.str() + "' is always " + bool_to_string(result) +
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". Check carefully constants and operators used, these errors might be hard to "
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"spot sometimes. In case of complex expression it might help to split it to "
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"separate expressions.");
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reportError(tok, Severity::style, "comparisonError", errmsg, CWE398, Certainty::normal);
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}
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bool CheckCondition::isOverlappingCond(const Token * const cond1, const Token * const cond2, bool pure) const
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{
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if (!cond1 || !cond2)
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return false;
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// same expressions
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if (isSameExpression(mTokenizer->isCPP(), true, cond1, cond2, mSettings->library, pure, false))
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return true;
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// bitwise overlap for example 'x&7' and 'x==1'
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if (cond1->str() == "&" && cond1->astOperand1() && cond2->astOperand2()) {
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const Token *expr1 = cond1->astOperand1();
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const Token *num1 = cond1->astOperand2();
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if (!num1) // unary operator&
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return false;
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if (!num1->isNumber())
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std::swap(expr1,num1);
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if (!num1->isNumber() || MathLib::isNegative(num1->str()))
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return false;
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|
|
|
if (!Token::Match(cond2, "&|==") || !cond2->astOperand1() || !cond2->astOperand2())
|
|
return false;
|
|
const Token *expr2 = cond2->astOperand1();
|
|
const Token *num2 = cond2->astOperand2();
|
|
if (!num2->isNumber())
|
|
std::swap(expr2,num2);
|
|
if (!num2->isNumber() || MathLib::isNegative(num2->str()))
|
|
return false;
|
|
|
|
if (!isSameExpression(mTokenizer->isCPP(), true, expr1, expr2, mSettings->library, pure, false))
|
|
return false;
|
|
|
|
const MathLib::bigint value1 = MathLib::toBigNumber(num1->str());
|
|
const MathLib::bigint value2 = MathLib::toBigNumber(num2->str());
|
|
if (cond2->str() == "&")
|
|
return ((value1 & value2) == value2);
|
|
return ((value1 & value2) > 0);
|
|
}
|
|
return false;
|
|
}
|
|
|
|
void CheckCondition::duplicateCondition()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::style))
|
|
return;
|
|
|
|
logChecker("CheckCondition::duplicateCondition"); // style
|
|
|
|
const SymbolDatabase *const symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
|
|
for (const Scope &scope : symbolDatabase->scopeList) {
|
|
if (scope.type != Scope::eIf)
|
|
continue;
|
|
|
|
const Token* tok2 = scope.classDef->next();
|
|
if (!tok2)
|
|
continue;
|
|
const Token* cond1 = tok2->astOperand2();
|
|
if (!cond1)
|
|
continue;
|
|
if (cond1->hasKnownIntValue())
|
|
continue;
|
|
|
|
tok2 = tok2->link();
|
|
if (!Token::simpleMatch(tok2, ") {"))
|
|
continue;
|
|
tok2 = tok2->linkAt(1);
|
|
if (!Token::simpleMatch(tok2, "} if ("))
|
|
continue;
|
|
const Token *cond2 = tok2->tokAt(2)->astOperand2();
|
|
if (!cond2)
|
|
continue;
|
|
|
|
ErrorPath errorPath;
|
|
if (!findExpressionChanged(cond1, scope.classDef->next(), cond2, mSettings, mTokenizer->isCPP()) &&
|
|
isSameExpression(mTokenizer->isCPP(), true, cond1, cond2, mSettings->library, true, true, &errorPath))
|
|
duplicateConditionError(cond1, cond2, errorPath);
|
|
}
|
|
}
|
|
|
|
void CheckCondition::duplicateConditionError(const Token *tok1, const Token *tok2, ErrorPath errorPath)
|
|
{
|
|
if (diag(tok1) & diag(tok2))
|
|
return;
|
|
errorPath.emplace_back(tok1, "First condition");
|
|
errorPath.emplace_back(tok2, "Second condition");
|
|
|
|
std::string msg = "The if condition is the same as the previous if condition";
|
|
|
|
reportError(errorPath, Severity::style, "duplicateCondition", msg, CWE398, Certainty::normal);
|
|
}
|
|
|
|
void CheckCondition::multiCondition()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::style))
|
|
return;
|
|
|
|
logChecker("CheckCondition::multiCondition"); // style
|
|
|
|
const SymbolDatabase* const symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
|
|
for (const Scope &scope : symbolDatabase->scopeList) {
|
|
if (scope.type != Scope::eIf)
|
|
continue;
|
|
|
|
const Token * const cond1 = scope.classDef->next()->astOperand2();
|
|
if (!cond1)
|
|
continue;
|
|
|
|
const Token * tok2 = scope.classDef->next();
|
|
|
|
// Check each 'else if'
|
|
for (;;) {
|
|
tok2 = tok2->link();
|
|
if (!Token::simpleMatch(tok2, ") {"))
|
|
break;
|
|
tok2 = tok2->linkAt(1);
|
|
if (!Token::simpleMatch(tok2, "} else { if ("))
|
|
break;
|
|
tok2 = tok2->tokAt(4);
|
|
|
|
if (tok2->astOperand2()) {
|
|
ErrorPath errorPath;
|
|
if (isOverlappingCond(cond1, tok2->astOperand2(), true) &&
|
|
!findExpressionChanged(cond1, cond1, tok2->astOperand2(), mSettings, mTokenizer->isCPP()))
|
|
overlappingElseIfConditionError(tok2->astOperand2(), cond1->linenr());
|
|
else if (isOppositeCond(
|
|
true, mTokenizer->isCPP(), cond1, tok2->astOperand2(), mSettings->library, true, true, &errorPath) &&
|
|
!findExpressionChanged(cond1, cond1, tok2->astOperand2(), mSettings, mTokenizer->isCPP()))
|
|
oppositeElseIfConditionError(cond1, tok2->astOperand2(), errorPath);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckCondition::overlappingElseIfConditionError(const Token *tok, nonneg int line1)
|
|
{
|
|
if (diag(tok))
|
|
return;
|
|
std::ostringstream errmsg;
|
|
errmsg << "Expression is always false because 'else if' condition matches previous condition at line "
|
|
<< line1 << ".";
|
|
|
|
reportError(tok, Severity::style, "multiCondition", errmsg.str(), CWE398, Certainty::normal);
|
|
}
|
|
|
|
void CheckCondition::oppositeElseIfConditionError(const Token *ifCond, const Token *elseIfCond, ErrorPath errorPath)
|
|
{
|
|
if (diag(ifCond) & diag(elseIfCond))
|
|
return;
|
|
std::ostringstream errmsg;
|
|
errmsg << "Expression is always true because 'else if' condition is opposite to previous condition at line "
|
|
<< ifCond->linenr() << ".";
|
|
|
|
errorPath.emplace_back(ifCond, "first condition");
|
|
errorPath.emplace_back(elseIfCond, "else if condition is opposite to first condition");
|
|
|
|
reportError(errorPath, Severity::style, "multiCondition", errmsg.str(), CWE398, Certainty::normal);
|
|
}
|
|
|
|
//---------------------------------------------------------------------------
|
|
// - Opposite inner conditions => always false
|
|
// - (TODO) Same/Overlapping inner condition => always true
|
|
// - same condition after early exit => always false
|
|
//---------------------------------------------------------------------------
|
|
|
|
static bool isNonConstFunctionCall(const Token *ftok, const Library &library)
|
|
{
|
|
if (library.isFunctionConst(ftok))
|
|
return false;
|
|
const Token *obj = ftok->next()->astOperand1();
|
|
while (obj && obj->str() == ".")
|
|
obj = obj->astOperand1();
|
|
if (!obj)
|
|
return true;
|
|
if (obj->variable() && obj->variable()->isConst())
|
|
return false;
|
|
if (ftok->function() && ftok->function()->isConst())
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
void CheckCondition::multiCondition2()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::warning))
|
|
return;
|
|
|
|
logChecker("CheckCondition::multiCondition2"); // warning
|
|
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
|
|
for (const Scope &scope : symbolDatabase->scopeList) {
|
|
const Token *condTok = nullptr;
|
|
if (scope.type == Scope::eIf || scope.type == Scope::eWhile)
|
|
condTok = scope.classDef->next()->astOperand2();
|
|
else if (scope.type == Scope::eFor) {
|
|
condTok = scope.classDef->next()->astOperand2();
|
|
if (!condTok || condTok->str() != ";")
|
|
continue;
|
|
condTok = condTok->astOperand2();
|
|
if (!condTok || condTok->str() != ";")
|
|
continue;
|
|
condTok = condTok->astOperand1();
|
|
}
|
|
if (!condTok)
|
|
continue;
|
|
const Token * const cond1 = condTok;
|
|
|
|
if (!Token::simpleMatch(scope.classDef->linkAt(1), ") {"))
|
|
continue;
|
|
|
|
bool functionCall = false;
|
|
bool nonConstFunctionCall = false;
|
|
bool nonlocal = false; // nonlocal variable used in condition
|
|
std::set<int> vars; // variables used in condition
|
|
visitAstNodes(condTok,
|
|
[&](const Token *cond) {
|
|
if (Token::Match(cond, "%name% (")) {
|
|
functionCall = true;
|
|
nonConstFunctionCall = isNonConstFunctionCall(cond, mSettings->library);
|
|
if (nonConstFunctionCall)
|
|
return ChildrenToVisit::done;
|
|
}
|
|
|
|
if (cond->varId()) {
|
|
vars.insert(cond->varId());
|
|
const Variable *var = cond->variable();
|
|
if (!nonlocal && var) {
|
|
if (!(var->isLocal() || var->isArgument()))
|
|
nonlocal = true;
|
|
else if ((var->isPointer() || var->isReference()) && !Token::Match(cond->astParent(), "%oror%|&&|!"))
|
|
// TODO: if var is pointer check what it points at
|
|
nonlocal = true;
|
|
}
|
|
} else if (!nonlocal && cond->isName()) {
|
|
// varid is 0. this is possibly a nonlocal variable..
|
|
nonlocal = Token::Match(cond->astParent(), "%cop%|(|[") || Token::Match(cond, "%name% .") || (mTokenizer->isCPP() && cond->str() == "this");
|
|
} else {
|
|
return ChildrenToVisit::op1_and_op2;
|
|
}
|
|
return ChildrenToVisit::none;
|
|
});
|
|
|
|
if (nonConstFunctionCall)
|
|
continue;
|
|
|
|
std::vector<const Variable*> varsInCond;
|
|
visitAstNodes(condTok,
|
|
[&varsInCond](const Token *cond) {
|
|
if (cond->variable()) {
|
|
const Variable *var = cond->variable();
|
|
if (std::find(varsInCond.cbegin(), varsInCond.cend(), var) == varsInCond.cend())
|
|
varsInCond.push_back(var);
|
|
}
|
|
return ChildrenToVisit::op1_and_op2;
|
|
});
|
|
|
|
// parse until second condition is reached..
|
|
enum MULTICONDITIONTYPE { INNER, AFTER };
|
|
const Token *tok;
|
|
|
|
// Parse inner condition first and then early return condition
|
|
std::vector<MULTICONDITIONTYPE> types = {MULTICONDITIONTYPE::INNER};
|
|
if (Token::Match(scope.bodyStart, "{ return|throw|continue|break"))
|
|
types.push_back(MULTICONDITIONTYPE::AFTER);
|
|
for (const MULTICONDITIONTYPE type:types) {
|
|
if (type == MULTICONDITIONTYPE::AFTER) {
|
|
tok = scope.bodyEnd->next();
|
|
} else {
|
|
tok = scope.bodyStart;
|
|
}
|
|
const Token * const endToken = tok->scope()->bodyEnd;
|
|
|
|
for (; tok && tok != endToken; tok = tok->next()) {
|
|
if (isExpressionChangedAt(cond1, tok, 0, false, mSettings, mTokenizer->isCPP()))
|
|
break;
|
|
if (Token::Match(tok, "if|return")) {
|
|
const Token * condStartToken = tok->str() == "if" ? tok->next() : tok;
|
|
const Token * condEndToken = tok->str() == "if" ? condStartToken->link() : Token::findsimplematch(condStartToken, ";");
|
|
// Does condition modify tracked variables?
|
|
if (findExpressionChanged(cond1, condStartToken, condEndToken, mSettings, mTokenizer->isCPP()))
|
|
break;
|
|
|
|
// Condition..
|
|
const Token *cond2 = tok->str() == "if" ? condStartToken->astOperand2() : condStartToken->astOperand1();
|
|
const bool isReturnVar = (tok->str() == "return" && !Token::Match(cond2, "%cop%"));
|
|
|
|
ErrorPath errorPath;
|
|
|
|
if (type == MULTICONDITIONTYPE::INNER) {
|
|
visitAstNodes(cond1, [&](const Token* firstCondition) {
|
|
if (!firstCondition)
|
|
return ChildrenToVisit::none;
|
|
if (firstCondition->str() == "&&") {
|
|
if (!isOppositeCond(false, mTokenizer->isCPP(), firstCondition, cond2, mSettings->library, true, true))
|
|
return ChildrenToVisit::op1_and_op2;
|
|
}
|
|
if (!firstCondition->hasKnownIntValue()) {
|
|
if (!isReturnVar && isOppositeCond(false, mTokenizer->isCPP(), firstCondition, cond2, mSettings->library, true, true, &errorPath)) {
|
|
if (!isAliased(vars))
|
|
oppositeInnerConditionError(firstCondition, cond2, errorPath);
|
|
} else if (!isReturnVar && isSameExpression(mTokenizer->isCPP(), true, firstCondition, cond2, mSettings->library, true, true, &errorPath)) {
|
|
identicalInnerConditionError(firstCondition, cond2, errorPath);
|
|
}
|
|
}
|
|
return ChildrenToVisit::none;
|
|
});
|
|
} else {
|
|
visitAstNodes(cond2, [&](const Token *secondCondition) {
|
|
if (secondCondition->str() == "||" || secondCondition->str() == "&&")
|
|
return ChildrenToVisit::op1_and_op2;
|
|
|
|
if ((!cond1->hasKnownIntValue() || !secondCondition->hasKnownIntValue()) &&
|
|
isSameExpression(mTokenizer->isCPP(), true, cond1, secondCondition, mSettings->library, true, true, &errorPath)) {
|
|
if (!isAliased(vars) && !mTokenizer->hasIfdef(cond1, secondCondition)) {
|
|
identicalConditionAfterEarlyExitError(cond1, secondCondition, errorPath);
|
|
return ChildrenToVisit::done;
|
|
}
|
|
}
|
|
return ChildrenToVisit::none;
|
|
});
|
|
}
|
|
}
|
|
if (Token::Match(tok, "%name% (") &&
|
|
isVariablesChanged(tok, tok->linkAt(1), 0, varsInCond, mSettings, mTokenizer->isCPP())) {
|
|
break;
|
|
}
|
|
if (Token::Match(tok, "%type% (") && nonlocal && isNonConstFunctionCall(tok, mSettings->library)) // non const function call -> bailout if there are nonlocal variables
|
|
break;
|
|
if (Token::Match(tok, "case|break|continue|return|throw") && tok->scope() == endToken->scope())
|
|
break;
|
|
if (Token::Match(tok, "[;{}] %name% :"))
|
|
break;
|
|
// bailout if loop is seen.
|
|
// TODO: handle loops better.
|
|
if (Token::Match(tok, "for|while|do")) {
|
|
const Token *tok1 = tok->next();
|
|
const Token *tok2;
|
|
if (Token::simpleMatch(tok, "do {")) {
|
|
if (!Token::simpleMatch(tok->linkAt(1), "} while ("))
|
|
break;
|
|
tok2 = tok->linkAt(1)->linkAt(2);
|
|
} else if (Token::Match(tok, "if|while (")) {
|
|
tok2 = tok->linkAt(1);
|
|
if (Token::simpleMatch(tok2, ") {"))
|
|
tok2 = tok2->linkAt(1);
|
|
if (!tok2)
|
|
break;
|
|
} else {
|
|
// Incomplete code
|
|
break;
|
|
}
|
|
const bool changed = std::any_of(vars.cbegin(), vars.cend(), [&](int varid) {
|
|
return isVariableChanged(tok1, tok2, varid, nonlocal, mSettings, mTokenizer->isCPP());
|
|
});
|
|
if (changed)
|
|
break;
|
|
}
|
|
if ((tok->varId() && vars.find(tok->varId()) != vars.end()) ||
|
|
(!tok->varId() && nonlocal) ||
|
|
(functionCall && tok->variable() && !tok->variable()->isLocal())) {
|
|
if (Token::Match(tok, "%name% %assign%|++|--"))
|
|
break;
|
|
if (Token::Match(tok->astParent(), "*|.|[")) {
|
|
const Token *parent = tok;
|
|
while (Token::Match(parent->astParent(), ".|[") || (parent->astParent() && parent->astParent()->isUnaryOp("*")))
|
|
parent = parent->astParent();
|
|
if (Token::Match(parent->astParent(), "%assign%|++|--"))
|
|
break;
|
|
}
|
|
if (mTokenizer->isCPP() && Token::Match(tok, "%name% <<") && (!tok->valueType() || !tok->valueType()->isIntegral()))
|
|
break;
|
|
if (isLikelyStreamRead(mTokenizer->isCPP(), tok->next()) || isLikelyStreamRead(mTokenizer->isCPP(), tok->previous()))
|
|
break;
|
|
if (Token::Match(tok, "%name% [")) {
|
|
const Token *tok2 = tok->linkAt(1);
|
|
while (Token::simpleMatch(tok2, "] ["))
|
|
tok2 = tok2->linkAt(1);
|
|
if (Token::Match(tok2, "] %assign%|++|--"))
|
|
break;
|
|
}
|
|
if (Token::Match(tok->previous(), "++|--|& %name%"))
|
|
break;
|
|
if (tok->variable() &&
|
|
!tok->variable()->isConst() &&
|
|
Token::Match(tok, "%name% . %name% (")) {
|
|
const Function* function = tok->tokAt(2)->function();
|
|
if (!function || !function->isConst())
|
|
break;
|
|
}
|
|
if (Token::Match(tok->previous(), "[(,] *|& %name% [,)]") && isParameterChanged(tok))
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
static std::string innerSmtString(const Token * tok)
|
|
{
|
|
if (!tok)
|
|
return "if";
|
|
if (!tok->astTop())
|
|
return "if";
|
|
const Token * top = tok->astTop();
|
|
if (top->str() == "(" && top->astOperand1())
|
|
return top->astOperand1()->str();
|
|
return top->str();
|
|
}
|
|
|
|
void CheckCondition::oppositeInnerConditionError(const Token *tok1, const Token* tok2, ErrorPath errorPath)
|
|
{
|
|
if (diag(tok1) & diag(tok2))
|
|
return;
|
|
const std::string s1(tok1 ? tok1->expressionString() : "x");
|
|
const std::string s2(tok2 ? tok2->expressionString() : "!x");
|
|
const std::string innerSmt = innerSmtString(tok2);
|
|
errorPath.emplace_back(tok1, "outer condition: " + s1);
|
|
errorPath.emplace_back(tok2, "opposite inner condition: " + s2);
|
|
|
|
const std::string msg("Opposite inner '" + innerSmt + "' condition leads to a dead code block.\n"
|
|
"Opposite inner '" + innerSmt + "' condition leads to a dead code block (outer condition is '" + s1 + "' and inner condition is '" + s2 + "').");
|
|
reportError(errorPath, Severity::warning, "oppositeInnerCondition", msg, CWE398, Certainty::normal);
|
|
}
|
|
|
|
void CheckCondition::identicalInnerConditionError(const Token *tok1, const Token* tok2, ErrorPath errorPath)
|
|
{
|
|
if (diag(tok1) & diag(tok2))
|
|
return;
|
|
const std::string s1(tok1 ? tok1->expressionString() : "x");
|
|
const std::string s2(tok2 ? tok2->expressionString() : "x");
|
|
const std::string innerSmt = innerSmtString(tok2);
|
|
errorPath.emplace_back(tok1, "outer condition: " + s1);
|
|
errorPath.emplace_back(tok2, "identical inner condition: " + s2);
|
|
|
|
const std::string msg("Identical inner '" + innerSmt + "' condition is always true.\n"
|
|
"Identical inner '" + innerSmt + "' condition is always true (outer condition is '" + s1 + "' and inner condition is '" + s2 + "').");
|
|
reportError(errorPath, Severity::warning, "identicalInnerCondition", msg, CWE398, Certainty::normal);
|
|
}
|
|
|
|
void CheckCondition::identicalConditionAfterEarlyExitError(const Token *cond1, const Token* cond2, ErrorPath errorPath)
|
|
{
|
|
if (diag(cond1) & diag(cond2))
|
|
return;
|
|
|
|
const bool isReturnValue = cond2 && Token::simpleMatch(cond2->astParent(), "return");
|
|
|
|
const std::string cond(cond1 ? cond1->expressionString() : "x");
|
|
const std::string value = (cond2 && cond2->valueType() && cond2->valueType()->type == ValueType::Type::BOOL) ? "false" : "0";
|
|
|
|
errorPath.emplace_back(cond1, "If condition '" + cond + "' is true, the function will return/exit");
|
|
errorPath.emplace_back(cond2, (isReturnValue ? "Returning identical expression '" : "Testing identical condition '") + cond + "'");
|
|
|
|
reportError(errorPath,
|
|
Severity::warning,
|
|
"identicalConditionAfterEarlyExit",
|
|
isReturnValue
|
|
? ("Identical condition and return expression '" + cond + "', return value is always " + value)
|
|
: ("Identical condition '" + cond + "', second condition is always false"),
|
|
CWE398,
|
|
Certainty::normal);
|
|
}
|
|
|
|
//---------------------------------------------------------------------------
|
|
// if ((x != 1) || (x != 3)) // expression always true
|
|
// if ((x == 1) && (x == 3)) // expression always false
|
|
// if ((x < 1) && (x > 3)) // expression always false
|
|
// if ((x > 3) || (x < 10)) // expression always true
|
|
// if ((x > 5) && (x != 1)) // second comparison always true
|
|
//
|
|
// Check for suspect logic for an expression consisting of 2 comparison
|
|
// expressions with a shared variable and constants and a logical operator
|
|
// between them.
|
|
//
|
|
// Suggest a different logical operator when the logical operator between
|
|
// the comparisons is probably wrong.
|
|
//
|
|
// Inform that second comparison is always true when first comparison is true.
|
|
//---------------------------------------------------------------------------
|
|
|
|
static std::string invertOperatorForOperandSwap(std::string s)
|
|
{
|
|
if (s[0] == '<')
|
|
s[0] = '>';
|
|
else if (s[0] == '>')
|
|
s[0] = '<';
|
|
return s;
|
|
}
|
|
|
|
template<typename T>
|
|
static int sign(const T v) {
|
|
return static_cast<int>(v > 0) - static_cast<int>(v < 0);
|
|
}
|
|
|
|
// returns 1 (-1) if the first (second) condition is sufficient, 0 if indeterminate
|
|
template<typename T>
|
|
static int sufficientCondition(std::string op1, const bool not1, const T value1, std::string op2, const bool not2, const T value2, const bool isAnd) {
|
|
auto transformOp = [](std::string& op, const bool invert) {
|
|
if (invert) {
|
|
if (op == "==")
|
|
op = "!=";
|
|
else if (op == "!=")
|
|
op = "==";
|
|
else if (op == "<")
|
|
op = ">=";
|
|
else if (op == ">")
|
|
op = "<=";
|
|
else if (op == "<=")
|
|
op = ">";
|
|
else if (op == ">=")
|
|
op = "<";
|
|
}
|
|
};
|
|
transformOp(op1, not1);
|
|
transformOp(op2, not2);
|
|
int res = 0;
|
|
bool equal = false;
|
|
if (op1 == op2) {
|
|
equal = true;
|
|
if (op1 == ">" || op1 == ">=")
|
|
res = sign(value1 - value2);
|
|
else if (op1 == "<" || op1 == "<=")
|
|
res = -sign(value1 - value2);
|
|
} else { // not equal
|
|
if (op1 == "!=")
|
|
res = 1;
|
|
else if (op2 == "!=")
|
|
res = -1;
|
|
else if (op1 == "==")
|
|
res = -1;
|
|
else if (op2 == "==")
|
|
res = 1;
|
|
else if (op1 == ">" && op2 == ">=")
|
|
res = sign(value1 - (value2 - 1));
|
|
else if (op1 == ">=" && op2 == ">")
|
|
res = sign((value1 - 1) - value2);
|
|
else if (op1 == "<" && op2 == "<=")
|
|
res = -sign(value1 - (value2 + 1));
|
|
else if (op1 == "<=" && op2 == "<")
|
|
res = -sign((value1 + 1) - value2);
|
|
}
|
|
return res * (isAnd == equal ? 1 : -1);
|
|
}
|
|
|
|
template<typename T>
|
|
static bool checkIntRelation(const std::string &op, const T value1, const T value2)
|
|
{
|
|
return (op == "==" && value1 == value2) ||
|
|
(op == "!=" && value1 != value2) ||
|
|
(op == ">" && value1 > value2) ||
|
|
(op == ">=" && value1 >= value2) ||
|
|
(op == "<" && value1 < value2) ||
|
|
(op == "<=" && value1 <= value2);
|
|
}
|
|
|
|
static bool checkFloatRelation(const std::string &op, const double value1, const double value2)
|
|
{
|
|
return (op == ">" && value1 > value2) ||
|
|
(op == ">=" && value1 >= value2) ||
|
|
(op == "<" && value1 < value2) ||
|
|
(op == "<=" && value1 <= value2);
|
|
}
|
|
|
|
template<class T>
|
|
static T getvalue3(const T value1, const T value2)
|
|
{
|
|
const T min = std::min(value1, value2);
|
|
if (min== std::numeric_limits<T>::max())
|
|
return min;
|
|
return min + 1; // see #5895
|
|
}
|
|
|
|
template<>
|
|
double getvalue3(const double value1, const double value2)
|
|
{
|
|
return (value1 + value2) / 2.0;
|
|
}
|
|
|
|
|
|
template<class T>
|
|
static inline T getvalue(const int test, const T value1, const T value2)
|
|
{
|
|
// test:
|
|
// 1 => return value that is less than both value1 and value2
|
|
// 2 => return value1
|
|
// 3 => return value that is between value1 and value2
|
|
// 4 => return value2
|
|
// 5 => return value that is larger than both value1 and value2
|
|
switch (test) {
|
|
case 1:
|
|
return std::numeric_limits<T>::lowest();
|
|
case 2:
|
|
return value1;
|
|
case 3:
|
|
return getvalue3<T>(value1, value2);
|
|
case 4:
|
|
return value2;
|
|
case 5:
|
|
return std::numeric_limits<T>::max();
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static bool parseComparison(const Token *comp, bool ¬1, std::string &op, std::string &value, const Token *&expr, bool &inconclusive)
|
|
{
|
|
not1 = false;
|
|
while (comp && comp->str() == "!") {
|
|
not1 = !(not1);
|
|
comp = comp->astOperand1();
|
|
}
|
|
|
|
if (!comp)
|
|
return false;
|
|
|
|
const Token* op1 = comp->astOperand1();
|
|
const Token* op2 = comp->astOperand2();
|
|
if (!comp->isComparisonOp() || !op1 || !op2) {
|
|
op = "!=";
|
|
value = "0";
|
|
expr = comp;
|
|
} else if (op1->isLiteral()) {
|
|
if (op1->isExpandedMacro())
|
|
return false;
|
|
op = invertOperatorForOperandSwap(comp->str());
|
|
if (op1->enumerator() && op1->enumerator()->value_known)
|
|
value = std::to_string(op1->enumerator()->value);
|
|
else
|
|
value = op1->str();
|
|
expr = op2;
|
|
} else if (comp->astOperand2()->isLiteral()) {
|
|
if (op2->isExpandedMacro())
|
|
return false;
|
|
op = comp->str();
|
|
if (op2->enumerator() && op2->enumerator()->value_known)
|
|
value = std::to_string(op2->enumerator()->value);
|
|
else
|
|
value = op2->str();
|
|
expr = op1;
|
|
} else {
|
|
op = "!=";
|
|
value = "0";
|
|
expr = comp;
|
|
}
|
|
|
|
inconclusive = inconclusive || ((value)[0] == '\'' && !(op == "!=" || op == "=="));
|
|
|
|
// Only float and int values are currently handled
|
|
return MathLib::isInt(value) || MathLib::isFloat(value) || (value[0] == '\'');
|
|
}
|
|
|
|
static std::string conditionString(bool not1, const Token *expr1, const std::string &op, const std::string &value1)
|
|
{
|
|
if (expr1->astParent()->isComparisonOp())
|
|
return std::string(not1 ? "!(" : "") + expr1->expressionString() +
|
|
" " +
|
|
op +
|
|
" " +
|
|
value1 +
|
|
(not1 ? ")" : "");
|
|
|
|
return std::string(not1 ? "!" : "") + expr1->expressionString();
|
|
}
|
|
|
|
static std::string conditionString(const Token * tok)
|
|
{
|
|
if (!tok)
|
|
return "";
|
|
if (tok->isComparisonOp()) {
|
|
bool inconclusive = false;
|
|
bool not_;
|
|
std::string op, value;
|
|
const Token *expr;
|
|
if (parseComparison(tok, not_, op, value, expr, inconclusive) && expr->isName()) {
|
|
return conditionString(not_, expr, op, value);
|
|
}
|
|
}
|
|
if (Token::Match(tok, "%cop%|&&|%oror%")) {
|
|
if (tok->astOperand2())
|
|
return conditionString(tok->astOperand1()) + " " + tok->str() + " " + conditionString(tok->astOperand2());
|
|
return tok->str() + "(" + conditionString(tok->astOperand1()) + ")";
|
|
|
|
}
|
|
return tok->expressionString();
|
|
}
|
|
|
|
static bool isIfConstexpr(const Token* tok) {
|
|
const Token* const top = tok->astTop();
|
|
return top && Token::simpleMatch(top->astOperand1(), "if") && top->astOperand1()->isConstexpr();
|
|
}
|
|
|
|
void CheckCondition::checkIncorrectLogicOperator()
|
|
{
|
|
const bool printStyle = mSettings->severity.isEnabled(Severity::style);
|
|
const bool printWarning = mSettings->severity.isEnabled(Severity::warning);
|
|
if (!printWarning && !printStyle)
|
|
return;
|
|
const bool printInconclusive = mSettings->certainty.isEnabled(Certainty::inconclusive);
|
|
|
|
logChecker("CheckCondition::checkIncorrectLogicOperator"); // style,warning
|
|
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
for (const Scope * scope : symbolDatabase->functionScopes) {
|
|
|
|
for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
|
|
if (!Token::Match(tok, "%oror%|&&") || !tok->astOperand1() || !tok->astOperand2())
|
|
continue;
|
|
|
|
|
|
// 'A && (!A || B)' is equivalent to 'A && B'
|
|
// 'A || (!A && B)' is equivalent to 'A || B'
|
|
// 'A && (A || B)' is equivalent to 'A'
|
|
// 'A || (A && B)' is equivalent to 'A'
|
|
if (printStyle &&
|
|
((tok->str() == "||" && tok->astOperand2()->str() == "&&") ||
|
|
(tok->str() == "&&" && tok->astOperand2()->str() == "||"))) {
|
|
const Token* tok2 = tok->astOperand2()->astOperand1();
|
|
if (isOppositeCond(true, mTokenizer->isCPP(), tok->astOperand1(), tok2, mSettings->library, true, false)) {
|
|
std::string expr1(tok->astOperand1()->expressionString());
|
|
std::string expr2(tok->astOperand2()->astOperand1()->expressionString());
|
|
std::string expr3(tok->astOperand2()->astOperand2()->expressionString());
|
|
// make copy for later because the original string might get overwritten
|
|
const std::string expr1VerboseMsg = expr1;
|
|
const std::string expr2VerboseMsg = expr2;
|
|
const std::string expr3VerboseMsg = expr3;
|
|
|
|
if (expr1.length() + expr2.length() + expr3.length() > 50U) {
|
|
if (expr1[0] == '!' && expr2[0] != '!') {
|
|
expr1 = "!A";
|
|
expr2 = "A";
|
|
} else {
|
|
expr1 = "A";
|
|
expr2 = "!A";
|
|
}
|
|
|
|
expr3 = "B";
|
|
}
|
|
|
|
const std::string cond1 = expr1 + " " + tok->str() + " (" + expr2 + " " + tok->astOperand2()->str() + " " + expr3 + ")";
|
|
const std::string cond2 = expr1 + " " + tok->str() + " " + expr3;
|
|
|
|
const std::string cond1VerboseMsg = expr1VerboseMsg + " " + tok->str() + " " + expr2VerboseMsg + " " + tok->astOperand2()->str() + " " + expr3VerboseMsg;
|
|
const std::string cond2VerboseMsg = expr1VerboseMsg + " " + tok->str() + " " + expr3VerboseMsg;
|
|
// for the --verbose message, transform the actual condition and print it
|
|
const std::string msg = tok2->expressionString() + ". '" + cond1 + "' is equivalent to '" + cond2 + "'\n"
|
|
"The condition '" + cond1VerboseMsg + "' is equivalent to '" + cond2VerboseMsg + "'.";
|
|
redundantConditionError(tok, msg, false);
|
|
continue;
|
|
}
|
|
if (isSameExpression(mTokenizer->isCPP(), false, tok->astOperand1(), tok2, mSettings->library, true, true)) {
|
|
std::string expr1(tok->astOperand1()->expressionString());
|
|
std::string expr2(tok->astOperand2()->astOperand1()->expressionString());
|
|
std::string expr3(tok->astOperand2()->astOperand2()->expressionString());
|
|
// make copy for later because the original string might get overwritten
|
|
const std::string expr1VerboseMsg = expr1;
|
|
const std::string expr2VerboseMsg = expr2;
|
|
const std::string expr3VerboseMsg = expr3;
|
|
|
|
if (expr1.length() + expr2.length() + expr3.length() > 50U) {
|
|
expr1 = "A";
|
|
expr2 = "A";
|
|
expr3 = "B";
|
|
}
|
|
|
|
const std::string cond1 = expr1 + " " + tok->str() + " (" + expr2 + " " + tok->astOperand2()->str() + " " + expr3 + ")";
|
|
const std::string cond2 = expr1;
|
|
|
|
const std::string cond1VerboseMsg = expr1VerboseMsg + " " + tok->str() + " " + expr2VerboseMsg + " " + tok->astOperand2()->str() + " " + expr3VerboseMsg;
|
|
const std::string& cond2VerboseMsg = expr1VerboseMsg;
|
|
// for the --verbose message, transform the actual condition and print it
|
|
const std::string msg = tok2->expressionString() + ". '" + cond1 + "' is equivalent to '" + cond2 + "'\n"
|
|
"The condition '" + cond1VerboseMsg + "' is equivalent to '" + cond2VerboseMsg + "'.";
|
|
redundantConditionError(tok, msg, false);
|
|
continue;
|
|
}
|
|
}
|
|
|
|
// Comparison #1 (LHS)
|
|
const Token *comp1 = tok->astOperand1();
|
|
if (comp1->str() == tok->str())
|
|
comp1 = comp1->astOperand2();
|
|
|
|
// Comparison #2 (RHS)
|
|
const Token *comp2 = tok->astOperand2();
|
|
|
|
bool inconclusive = false;
|
|
bool parseable = true;
|
|
|
|
// Parse LHS
|
|
bool not1;
|
|
std::string op1, value1;
|
|
const Token *expr1 = nullptr;
|
|
parseable &= (parseComparison(comp1, not1, op1, value1, expr1, inconclusive));
|
|
|
|
// Parse RHS
|
|
bool not2;
|
|
std::string op2, value2;
|
|
const Token *expr2 = nullptr;
|
|
parseable &= (parseComparison(comp2, not2, op2, value2, expr2, inconclusive));
|
|
|
|
if (inconclusive && !printInconclusive)
|
|
continue;
|
|
|
|
const bool isUnknown = (expr1 && expr1->valueType() && expr1->valueType()->type == ValueType::UNKNOWN_TYPE) ||
|
|
(expr2 && expr2->valueType() && expr2->valueType()->type == ValueType::UNKNOWN_TYPE);
|
|
if (isUnknown)
|
|
continue;
|
|
|
|
const bool isfloat = astIsFloat(expr1, true) || MathLib::isFloat(value1) || astIsFloat(expr2, true) || MathLib::isFloat(value2);
|
|
|
|
ErrorPath errorPath;
|
|
|
|
// Opposite comparisons around || or && => always true or always false
|
|
const bool isLogicalOr(tok->str() == "||");
|
|
if (!isfloat && isOppositeCond(isLogicalOr, mTokenizer->isCPP(), tok->astOperand1(), tok->astOperand2(), mSettings->library, true, true, &errorPath)) {
|
|
if (!isIfConstexpr(tok)) {
|
|
const bool alwaysTrue(isLogicalOr);
|
|
incorrectLogicOperatorError(tok, conditionString(tok), alwaysTrue, inconclusive, errorPath);
|
|
}
|
|
continue;
|
|
}
|
|
|
|
if (!parseable)
|
|
continue;
|
|
|
|
if (isSameExpression(mTokenizer->isCPP(), true, comp1, comp2, mSettings->library, true, true))
|
|
continue; // same expressions => only report that there are same expressions
|
|
if (!isSameExpression(mTokenizer->isCPP(), true, expr1, expr2, mSettings->library, true, true))
|
|
continue;
|
|
|
|
|
|
// don't check floating point equality comparisons. that is bad
|
|
// and deserves different warnings.
|
|
if (isfloat && (op1 == "==" || op1 == "!=" || op2 == "==" || op2 == "!="))
|
|
continue;
|
|
|
|
|
|
const double d1 = (isfloat) ? MathLib::toDoubleNumber(value1) : 0;
|
|
const double d2 = (isfloat) ? MathLib::toDoubleNumber(value2) : 0;
|
|
const MathLib::bigint i1 = (isfloat) ? 0 : MathLib::toBigNumber(value1);
|
|
const MathLib::bigint i2 = (isfloat) ? 0 : MathLib::toBigNumber(value2);
|
|
const bool useUnsignedInt = (std::numeric_limits<MathLib::bigint>::max()==i1) || (std::numeric_limits<MathLib::bigint>::max()==i2);
|
|
const MathLib::biguint u1 = (useUnsignedInt) ? MathLib::toBigNumber(value1) : 0;
|
|
const MathLib::biguint u2 = (useUnsignedInt) ? MathLib::toBigNumber(value2) : 0;
|
|
// evaluate if expression is always true/false
|
|
bool alwaysTrue = true, alwaysFalse = true;
|
|
bool firstTrue = true, secondTrue = true;
|
|
const bool isAnd = tok->str() == "&&";
|
|
for (int test = 1; test <= 5; ++test) {
|
|
// test:
|
|
// 1 => testvalue is less than both value1 and value2
|
|
// 2 => testvalue is value1
|
|
// 3 => testvalue is between value1 and value2
|
|
// 4 => testvalue value2
|
|
// 5 => testvalue is larger than both value1 and value2
|
|
bool result1, result2;
|
|
if (isfloat) {
|
|
const double testvalue = getvalue<double>(test, d1, d2);
|
|
result1 = checkFloatRelation(op1, testvalue, d1);
|
|
result2 = checkFloatRelation(op2, testvalue, d2);
|
|
} else if (useUnsignedInt) {
|
|
const MathLib::biguint testvalue = getvalue<MathLib::biguint>(test, u1, u2);
|
|
result1 = checkIntRelation(op1, testvalue, u1);
|
|
result2 = checkIntRelation(op2, testvalue, u2);
|
|
} else {
|
|
const MathLib::bigint testvalue = getvalue<MathLib::bigint>(test, i1, i2);
|
|
result1 = checkIntRelation(op1, testvalue, i1);
|
|
result2 = checkIntRelation(op2, testvalue, i2);
|
|
}
|
|
if (not1)
|
|
result1 = !result1;
|
|
if (not2)
|
|
result2 = !result2;
|
|
if (isAnd) {
|
|
alwaysTrue &= (result1 && result2);
|
|
alwaysFalse &= !(result1 && result2);
|
|
} else {
|
|
alwaysTrue &= (result1 || result2);
|
|
alwaysFalse &= !(result1 || result2);
|
|
}
|
|
firstTrue &= !(!result1 && result2);
|
|
secondTrue &= !(result1 && !result2);
|
|
}
|
|
|
|
const std::string cond1str = conditionString(not1, expr1, op1, value1);
|
|
const std::string cond2str = conditionString(not2, expr2, op2, value2);
|
|
if (printWarning && (alwaysTrue || alwaysFalse)) {
|
|
const std::string text = cond1str + " " + tok->str() + " " + cond2str;
|
|
incorrectLogicOperatorError(tok, text, alwaysTrue, inconclusive, errorPath);
|
|
} else if (printStyle && (firstTrue || secondTrue)) {
|
|
const int which = isfloat ? sufficientCondition(op1, not1, d1, op2, not2, d2, isAnd) : sufficientCondition(op1, not1, i1, op2, not2, i2, isAnd);
|
|
std::string text;
|
|
if (which != 0) {
|
|
text = "The condition '" + (which == 1 ? cond2str : cond1str) + "' is redundant since '" + (which == 1 ? cond1str : cond2str) + "' is sufficient.";
|
|
} else
|
|
text = "If '" + (secondTrue ? cond1str : cond2str) + "', the comparison '" + (secondTrue ? cond2str : cond1str) + "' is always true.";
|
|
redundantConditionError(tok, text, inconclusive);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckCondition::incorrectLogicOperatorError(const Token *tok, const std::string &condition, bool always, bool inconclusive, ErrorPath errors)
|
|
{
|
|
if (diag(tok))
|
|
return;
|
|
errors.emplace_back(tok, "");
|
|
if (always)
|
|
reportError(errors, Severity::warning, "incorrectLogicOperator",
|
|
"Logical disjunction always evaluates to true: " + condition + ".\n"
|
|
"Logical disjunction always evaluates to true: " + condition + ". "
|
|
"Are these conditions necessary? Did you intend to use && instead? Are the numbers correct? Are you comparing the correct variables?", CWE571, inconclusive ? Certainty::inconclusive : Certainty::normal);
|
|
else
|
|
reportError(errors, Severity::warning, "incorrectLogicOperator",
|
|
"Logical conjunction always evaluates to false: " + condition + ".\n"
|
|
"Logical conjunction always evaluates to false: " + condition + ". "
|
|
"Are these conditions necessary? Did you intend to use || instead? Are the numbers correct? Are you comparing the correct variables?", CWE570, inconclusive ? Certainty::inconclusive : Certainty::normal);
|
|
}
|
|
|
|
void CheckCondition::redundantConditionError(const Token *tok, const std::string &text, bool inconclusive)
|
|
{
|
|
if (diag(tok))
|
|
return;
|
|
reportError(tok, Severity::style, "redundantCondition", "Redundant condition: " + text, CWE398, inconclusive ? Certainty::inconclusive : Certainty::normal);
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------
|
|
// Detect "(var % val1) > val2" where val2 is >= val1.
|
|
//-----------------------------------------------------------------------------
|
|
void CheckCondition::checkModuloAlwaysTrueFalse()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::warning))
|
|
return;
|
|
|
|
logChecker("CheckCondition::checkModuloAlwaysTrueFalse"); // warning
|
|
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
for (const Scope * scope : symbolDatabase->functionScopes) {
|
|
for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
|
|
if (!tok->isComparisonOp())
|
|
continue;
|
|
const Token *num, *modulo;
|
|
if (Token::simpleMatch(tok->astOperand1(), "%") && Token::Match(tok->astOperand2(), "%num%")) {
|
|
modulo = tok->astOperand1();
|
|
num = tok->astOperand2();
|
|
} else if (Token::Match(tok->astOperand1(), "%num%") && Token::simpleMatch(tok->astOperand2(), "%")) {
|
|
num = tok->astOperand1();
|
|
modulo = tok->astOperand2();
|
|
} else {
|
|
continue;
|
|
}
|
|
|
|
if (Token::Match(modulo->astOperand2(), "%num%") &&
|
|
MathLib::isLessEqual(modulo->astOperand2()->str(), num->str()))
|
|
moduloAlwaysTrueFalseError(tok, modulo->astOperand2()->str());
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckCondition::moduloAlwaysTrueFalseError(const Token* tok, const std::string& maxVal)
|
|
{
|
|
if (diag(tok))
|
|
return;
|
|
reportError(tok, Severity::warning, "moduloAlwaysTrueFalse",
|
|
"Comparison of modulo result is predetermined, because it is always less than " + maxVal + ".", CWE398, Certainty::normal);
|
|
}
|
|
|
|
static int countPar(const Token *tok1, const Token *tok2)
|
|
{
|
|
int par = 0;
|
|
for (const Token *tok = tok1; tok && tok != tok2; tok = tok->next()) {
|
|
if (tok->str() == "(")
|
|
++par;
|
|
else if (tok->str() == ")")
|
|
--par;
|
|
else if (tok->str() == ";")
|
|
return -1;
|
|
}
|
|
return par;
|
|
}
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Clarify condition '(x = a < 0)' into '((x = a) < 0)' or '(x = (a < 0))'
|
|
// Clarify condition '(a & b == c)' into '((a & b) == c)' or '(a & (b == c))'
|
|
//---------------------------------------------------------------------------
|
|
void CheckCondition::clarifyCondition()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::style))
|
|
return;
|
|
|
|
const bool isC = mTokenizer->isC();
|
|
|
|
logChecker("CheckCondition::clarifyCondition"); // style
|
|
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
for (const Scope * scope : symbolDatabase->functionScopes) {
|
|
for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
|
|
if (Token::Match(tok, "( %name% [=&|^]")) {
|
|
for (const Token *tok2 = tok->tokAt(3); tok2; tok2 = tok2->next()) {
|
|
if (tok2->str() == "(" || tok2->str() == "[")
|
|
tok2 = tok2->link();
|
|
else if (tok2->isComparisonOp()) {
|
|
// This might be a template
|
|
if (!isC && tok2->link())
|
|
break;
|
|
if (Token::simpleMatch(tok2->astParent(), "?"))
|
|
break;
|
|
clarifyConditionError(tok, tok->strAt(2) == "=", false);
|
|
break;
|
|
} else if (!tok2->isName() && !tok2->isNumber() && tok2->str() != ".")
|
|
break;
|
|
}
|
|
} else if (tok->tokType() == Token::eBitOp && !tok->isUnaryOp("&")) {
|
|
if (tok->astOperand2() && tok->astOperand2()->variable() && tok->astOperand2()->variable()->nameToken() == tok->astOperand2())
|
|
continue;
|
|
|
|
// using boolean result in bitwise operation ! x [&|^]
|
|
const ValueType* vt1 = tok->astOperand1() ? tok->astOperand1()->valueType() : nullptr;
|
|
const ValueType* vt2 = tok->astOperand2() ? tok->astOperand2()->valueType() : nullptr;
|
|
if (vt1 && vt1->type == ValueType::BOOL && !Token::Match(tok->astOperand1(), "%name%|(|[|::|.") && countPar(tok->astOperand1(), tok) == 0)
|
|
clarifyConditionError(tok, false, true);
|
|
else if (vt2 && vt2->type == ValueType::BOOL && !Token::Match(tok->astOperand2(), "%name%|(|[|::|.") && countPar(tok, tok->astOperand2()) == 0)
|
|
clarifyConditionError(tok, false, true);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckCondition::clarifyConditionError(const Token *tok, bool assign, bool boolop)
|
|
{
|
|
std::string errmsg;
|
|
|
|
if (assign)
|
|
errmsg = "Suspicious condition (assignment + comparison); Clarify expression with parentheses.";
|
|
|
|
else if (boolop)
|
|
errmsg = "Boolean result is used in bitwise operation. Clarify expression with parentheses.\n"
|
|
"Suspicious expression. Boolean result is used in bitwise operation. The operator '!' "
|
|
"and the comparison operators have higher precedence than bitwise operators. "
|
|
"It is recommended that the expression is clarified with parentheses.";
|
|
else
|
|
errmsg = "Suspicious condition (bitwise operator + comparison); Clarify expression with parentheses.\n"
|
|
"Suspicious condition. Comparison operators have higher precedence than bitwise operators. "
|
|
"Please clarify the condition with parentheses.";
|
|
|
|
reportError(tok,
|
|
Severity::style,
|
|
"clarifyCondition",
|
|
errmsg, CWE398, Certainty::normal);
|
|
}
|
|
|
|
void CheckCondition::alwaysTrueFalse()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::style))
|
|
return;
|
|
|
|
logChecker("CheckCondition::alwaysTrueFalse"); // style
|
|
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
for (const Scope * scope : symbolDatabase->functionScopes) {
|
|
for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
|
|
// don't write false positives when templates are used or inside of asserts or non-evaluated contexts
|
|
if (tok->link() && (Token::simpleMatch(tok, "<") ||
|
|
Token::Match(tok->previous(), "static_assert|assert|ASSERT|sizeof|decltype ("))) {
|
|
tok = tok->link();
|
|
continue;
|
|
}
|
|
if (!tok->hasKnownIntValue())
|
|
continue;
|
|
if (Token::Match(tok->previous(), "%name% (") && tok->previous()->function()) {
|
|
const Function* f = tok->previous()->function();
|
|
if (f->functionScope && Token::Match(f->functionScope->bodyStart, "{ return true|false ;"))
|
|
continue;
|
|
}
|
|
const Token* condition = nullptr;
|
|
{
|
|
// is this a condition..
|
|
const Token *parent = tok->astParent();
|
|
while (Token::Match(parent, "%oror%|&&"))
|
|
parent = parent->astParent();
|
|
if (!parent)
|
|
continue;
|
|
if (parent->str() == "?" && precedes(tok, parent))
|
|
condition = parent;
|
|
else if (Token::Match(parent->previous(), "if|while ("))
|
|
condition = parent->previous();
|
|
else if (Token::simpleMatch(parent, "return"))
|
|
condition = parent;
|
|
else if (parent->str() == ";" && parent->astParent() && parent->astParent()->astParent() &&
|
|
Token::simpleMatch(parent->astParent()->astParent()->previous(), "for ("))
|
|
condition = parent->astParent()->astParent()->previous();
|
|
else if (Token::Match(tok, "%comp%"))
|
|
condition = tok;
|
|
else
|
|
continue;
|
|
}
|
|
// Skip already diagnosed values
|
|
if (diag(tok, false))
|
|
continue;
|
|
if (condition->isConstexpr())
|
|
continue;
|
|
if (!isUsedAsBool(tok))
|
|
continue;
|
|
if (Token::simpleMatch(condition, "return") && Token::Match(tok, "%assign%"))
|
|
continue;
|
|
if (Token::simpleMatch(tok->astParent(), "return") && Token::Match(tok, ".|%var%"))
|
|
continue;
|
|
if (Token::Match(tok, "%num%|%bool%|%char%"))
|
|
continue;
|
|
if (Token::Match(tok, "! %num%|%bool%|%char%"))
|
|
continue;
|
|
if (Token::Match(tok, "%oror%|&&") &&
|
|
(tok->astOperand1()->hasKnownIntValue() || tok->astOperand2()->hasKnownIntValue()))
|
|
continue;
|
|
if (Token::simpleMatch(tok, ":"))
|
|
continue;
|
|
if (Token::Match(tok->astOperand1(), "%name% (") && Token::simpleMatch(tok->astParent(), "return"))
|
|
continue;
|
|
if (tok->isComparisonOp() && isWithoutSideEffects(mTokenizer->isCPP(), tok->astOperand1()) &&
|
|
isSameExpression(mTokenizer->isCPP(),
|
|
true,
|
|
tok->astOperand1(),
|
|
tok->astOperand2(),
|
|
mSettings->library,
|
|
true,
|
|
true))
|
|
continue;
|
|
if (isConstVarExpression(tok, [](const Token* tok) {
|
|
return Token::Match(tok, "[|(|&|+|-|*|/|%|^|>>|<<") && !Token::simpleMatch(tok, "( )");
|
|
}))
|
|
continue;
|
|
|
|
// there are specific warnings about nonzero expressions (pointer/unsigned)
|
|
// do not write alwaysTrueFalse for these comparisons.
|
|
{
|
|
const ValueFlow::Value *zeroValue = nullptr;
|
|
const Token *nonZeroExpr = nullptr;
|
|
if (CheckOther::comparisonNonZeroExpressionLessThanZero(tok, &zeroValue, &nonZeroExpr) ||
|
|
CheckOther::testIfNonZeroExpressionIsPositive(tok, &zeroValue, &nonZeroExpr))
|
|
continue;
|
|
}
|
|
|
|
// Don't warn when there are expanded macros..
|
|
bool isExpandedMacro = false;
|
|
visitAstNodes(tok, [&](const Token * tok2) {
|
|
if (!tok2)
|
|
return ChildrenToVisit::none;
|
|
if (tok2->isExpandedMacro()) {
|
|
isExpandedMacro = true;
|
|
return ChildrenToVisit::done;
|
|
}
|
|
return ChildrenToVisit::op1_and_op2;
|
|
});
|
|
if (isExpandedMacro)
|
|
continue;
|
|
for (const Token *parent = tok; parent; parent = parent->astParent()) {
|
|
if (parent->isExpandedMacro()) {
|
|
isExpandedMacro = true;
|
|
break;
|
|
}
|
|
}
|
|
if (isExpandedMacro)
|
|
continue;
|
|
|
|
// don't warn when condition checks sizeof result
|
|
bool hasSizeof = false;
|
|
visitAstNodes(tok, [&](const Token * tok2) {
|
|
if (!tok2)
|
|
return ChildrenToVisit::none;
|
|
if (tok2->isNumber())
|
|
return ChildrenToVisit::none;
|
|
if (Token::simpleMatch(tok2->previous(), "sizeof (")) {
|
|
hasSizeof = true;
|
|
return ChildrenToVisit::none;
|
|
}
|
|
if (tok2->isComparisonOp() || tok2->isArithmeticalOp()) {
|
|
return ChildrenToVisit::op1_and_op2;
|
|
}
|
|
return ChildrenToVisit::none;
|
|
});
|
|
if (hasSizeof)
|
|
continue;
|
|
|
|
alwaysTrueFalseError(tok, condition, &tok->values().front());
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckCondition::alwaysTrueFalseError(const Token* tok, const Token* condition, const ValueFlow::Value* value)
|
|
{
|
|
const bool alwaysTrue = value && (value->intvalue != 0 || value->isImpossible());
|
|
const std::string expr = tok ? tok->expressionString() : std::string("x");
|
|
const std::string conditionStr = (Token::simpleMatch(condition, "return") ? "Return value" : "Condition");
|
|
const std::string errmsg = conditionStr + " '" + expr + "' is always " + bool_to_string(alwaysTrue);
|
|
const ErrorPath errorPath = getErrorPath(tok, value, errmsg);
|
|
reportError(errorPath,
|
|
Severity::style,
|
|
"knownConditionTrueFalse",
|
|
errmsg,
|
|
(alwaysTrue ? CWE571 : CWE570), Certainty::normal);
|
|
}
|
|
|
|
void CheckCondition::checkInvalidTestForOverflow()
|
|
{
|
|
// Interesting blogs:
|
|
// https://www.airs.com/blog/archives/120
|
|
// https://kristerw.blogspot.com/2016/02/how-undefined-signed-overflow-enables.html
|
|
// https://research.checkpoint.com/2020/optout-compiler-undefined-behavior-optimizations/
|
|
|
|
// x + c < x -> false
|
|
// x + c <= x -> false
|
|
// x + c > x -> true
|
|
// x + c >= x -> true
|
|
|
|
// x + y < x -> y < 0
|
|
|
|
|
|
if (!mSettings->severity.isEnabled(Severity::warning))
|
|
return;
|
|
|
|
logChecker("CheckCondition::checkInvalidTestForOverflow"); // warning
|
|
|
|
for (const Token *tok = mTokenizer->tokens(); tok; tok = tok->next()) {
|
|
if (!Token::Match(tok, "<|<=|>=|>") || !tok->isBinaryOp())
|
|
continue;
|
|
|
|
const Token *lhsTokens[2] = {tok->astOperand1(), tok->astOperand2()};
|
|
for (const Token *lhs: lhsTokens) {
|
|
std::string cmp = tok->str();
|
|
if (lhs == tok->astOperand2())
|
|
cmp[0] = (cmp[0] == '<') ? '>' : '<';
|
|
|
|
if (!Token::Match(lhs, "[+-]") || !lhs->isBinaryOp())
|
|
continue;
|
|
|
|
const bool isSignedInteger = lhs->valueType() && lhs->valueType()->isIntegral() && lhs->valueType()->sign == ValueType::Sign::SIGNED;
|
|
const bool isPointer = lhs->valueType() && lhs->valueType()->pointer > 0;
|
|
if (!isSignedInteger && !isPointer)
|
|
continue;
|
|
|
|
const Token *exprTokens[2] = {lhs->astOperand1(), lhs->astOperand2()};
|
|
for (const Token *expr: exprTokens) {
|
|
if (lhs->str() == "-" && expr == lhs->astOperand2())
|
|
continue; // TODO?
|
|
|
|
if (expr->hasKnownIntValue())
|
|
continue;
|
|
|
|
if (!isSameExpression(mTokenizer->isCPP(),
|
|
true,
|
|
expr,
|
|
lhs->astSibling(),
|
|
mSettings->library,
|
|
true,
|
|
false))
|
|
continue;
|
|
|
|
const Token * const other = expr->astSibling();
|
|
|
|
// x [+-] c cmp x
|
|
if ((other->isNumber() && other->getKnownIntValue() > 0) ||
|
|
(!other->isNumber() && other->valueType() && other->valueType()->isIntegral() && other->valueType()->sign == ValueType::Sign::UNSIGNED)) {
|
|
bool result;
|
|
if (lhs->str() == "+")
|
|
result = (cmp == ">" || cmp == ">=");
|
|
else
|
|
result = (cmp == "<" || cmp == "<=");
|
|
invalidTestForOverflow(tok, lhs->valueType(), bool_to_string(result));
|
|
continue;
|
|
}
|
|
|
|
// x + y cmp x
|
|
if (lhs->str() == "+" && other->varId() > 0) {
|
|
const std::string result = other->str() + cmp + "0";
|
|
invalidTestForOverflow(tok, lhs->valueType(), result);
|
|
continue;
|
|
}
|
|
|
|
// x - y cmp x
|
|
if (lhs->str() == "-" && other->varId() > 0) {
|
|
std::string cmp2 = cmp;
|
|
cmp2[0] = (cmp[0] == '<') ? '>' : '<';
|
|
const std::string result = other->str() + cmp2 + "0";
|
|
invalidTestForOverflow(tok, lhs->valueType(), result);
|
|
continue;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckCondition::invalidTestForOverflow(const Token* tok, const ValueType *valueType, const std::string &replace)
|
|
{
|
|
const std::string expr = (tok ? tok->expressionString() : std::string("x + c < x"));
|
|
const std::string overflow = (valueType && valueType->pointer) ? "pointer overflow" : "signed integer overflow";
|
|
|
|
std::string errmsg =
|
|
"Invalid test for overflow '" + expr + "'; " + overflow + " is undefined behavior.";
|
|
if (replace == "false" || replace == "true")
|
|
errmsg += " Some mainstream compilers remove such overflow tests when optimising the code and assume it's always " + replace + ".";
|
|
else
|
|
errmsg += " Some mainstream compilers removes handling of overflows when optimising the code and change the code to '" + replace + "'.";
|
|
reportError(tok, Severity::warning, "invalidTestForOverflow", errmsg, uncheckedErrorConditionCWE, Certainty::normal);
|
|
}
|
|
|
|
|
|
void CheckCondition::checkPointerAdditionResultNotNull()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::warning))
|
|
return;
|
|
|
|
logChecker("CheckCondition::checkPointerAdditionResultNotNull"); // warning
|
|
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
for (const Scope * scope : symbolDatabase->functionScopes) {
|
|
|
|
for (const Token* tok = scope->bodyStart; tok != scope->bodyEnd; tok = tok->next()) {
|
|
if (!tok->isComparisonOp() || !tok->astOperand1() || !tok->astOperand2())
|
|
continue;
|
|
|
|
// Macros might have pointless safety checks
|
|
if (tok->isExpandedMacro())
|
|
continue;
|
|
|
|
const Token *calcToken, *exprToken;
|
|
if (tok->astOperand1()->str() == "+") {
|
|
calcToken = tok->astOperand1();
|
|
exprToken = tok->astOperand2();
|
|
} else if (tok->astOperand2()->str() == "+") {
|
|
calcToken = tok->astOperand2();
|
|
exprToken = tok->astOperand1();
|
|
} else
|
|
continue;
|
|
|
|
// pointer comparison against NULL (ptr+12==0)
|
|
if (calcToken->hasKnownIntValue())
|
|
continue;
|
|
if (!calcToken->valueType() || calcToken->valueType()->pointer==0)
|
|
continue;
|
|
if (!exprToken->hasKnownIntValue() || !exprToken->getValue(0))
|
|
continue;
|
|
|
|
pointerAdditionResultNotNullError(tok, calcToken);
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckCondition::pointerAdditionResultNotNullError(const Token *tok, const Token *calc)
|
|
{
|
|
const std::string s = calc ? calc->expressionString() : "ptr+1";
|
|
reportError(tok, Severity::warning, "pointerAdditionResultNotNull", "Comparison is wrong. Result of '" + s + "' can't be 0 unless there is pointer overflow, and pointer overflow is undefined behaviour.");
|
|
}
|
|
|
|
void CheckCondition::checkDuplicateConditionalAssign()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::style))
|
|
return;
|
|
|
|
logChecker("CheckCondition::checkDuplicateConditionalAssign"); // style
|
|
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
for (const Scope *scope : symbolDatabase->functionScopes) {
|
|
for (const Token *tok = scope->bodyStart; tok != scope->bodyEnd; tok = tok->next()) {
|
|
if (!Token::simpleMatch(tok, "if ("))
|
|
continue;
|
|
if (!Token::simpleMatch(tok->next()->link(), ") {"))
|
|
continue;
|
|
const Token *blockTok = tok->next()->link()->next();
|
|
const Token *condTok = tok->next()->astOperand2();
|
|
const bool isBoolVar = Token::Match(condTok, "!| %var%");
|
|
if (!isBoolVar && !Token::Match(condTok, "==|!="))
|
|
continue;
|
|
if ((isBoolVar || condTok->str() == "!=") && Token::simpleMatch(blockTok->link(), "} else {"))
|
|
continue;
|
|
if (!blockTok->next())
|
|
continue;
|
|
const Token *assignTok = blockTok->next()->astTop();
|
|
if (!Token::simpleMatch(assignTok, "="))
|
|
continue;
|
|
if (nextAfterAstRightmostLeaf(assignTok) != blockTok->link()->previous())
|
|
continue;
|
|
bool isRedundant = false;
|
|
if (isBoolVar) {
|
|
const bool isNegation = condTok->str() == "!";
|
|
const Token* const varTok = isNegation ? condTok->next() : condTok;
|
|
const ValueType* vt = varTok->variable() ? varTok->variable()->valueType() : nullptr;
|
|
if (!(vt && vt->type == ValueType::Type::BOOL && !vt->pointer))
|
|
continue;
|
|
|
|
if (!(assignTok->astOperand1() && assignTok->astOperand1()->varId() == varTok->varId()))
|
|
continue;
|
|
if (!(assignTok->astOperand2() && assignTok->astOperand2()->hasKnownIntValue()))
|
|
continue;
|
|
const MathLib::bigint val = assignTok->astOperand2()->getKnownIntValue();
|
|
if (val < 0 || val > 1)
|
|
continue;
|
|
isRedundant = (isNegation && val == 0) || (!isNegation && val == 1);
|
|
} else { // comparison
|
|
if (!isSameExpression(
|
|
mTokenizer->isCPP(), true, condTok->astOperand1(), assignTok->astOperand1(), mSettings->library, true, true))
|
|
continue;
|
|
if (!isSameExpression(
|
|
mTokenizer->isCPP(), true, condTok->astOperand2(), assignTok->astOperand2(), mSettings->library, true, true))
|
|
continue;
|
|
}
|
|
duplicateConditionalAssignError(condTok, assignTok, isRedundant);
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckCondition::duplicateConditionalAssignError(const Token *condTok, const Token* assignTok, bool isRedundant)
|
|
{
|
|
ErrorPath errors;
|
|
std::string msg = "Duplicate expression for the condition and assignment.";
|
|
if (condTok && assignTok) {
|
|
if (condTok->str() == "==") {
|
|
msg = "Assignment '" + assignTok->expressionString() + "' is redundant with condition '" + condTok->expressionString() + "'.";
|
|
errors.emplace_back(condTok, "Condition '" + condTok->expressionString() + "'");
|
|
errors.emplace_back(assignTok, "Assignment '" + assignTok->expressionString() + "' is redundant");
|
|
} else {
|
|
msg = "The statement 'if (" + condTok->expressionString() + ") " + assignTok->expressionString();
|
|
msg += isRedundant ? "' is redundant." : "' is logically equivalent to '" + assignTok->expressionString() + "'.";
|
|
errors.emplace_back(assignTok, "Assignment '" + assignTok->expressionString() + "'");
|
|
errors.emplace_back(condTok, "Condition '" + condTok->expressionString() + "' is redundant");
|
|
}
|
|
}
|
|
|
|
reportError(
|
|
errors, Severity::style, "duplicateConditionalAssign", msg, CWE398, Certainty::normal);
|
|
}
|
|
|
|
|
|
void CheckCondition::checkAssignmentInCondition()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::style))
|
|
return;
|
|
|
|
logChecker("CheckCondition::checkAssignmentInCondition"); // style
|
|
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
for (const Scope * scope : symbolDatabase->functionScopes) {
|
|
for (const Token* tok = scope->bodyStart; tok != scope->bodyEnd; tok = tok->next()) {
|
|
if (tok->str() != "=")
|
|
continue;
|
|
if (!tok->astParent())
|
|
continue;
|
|
|
|
// Is this assignment of container/iterator?
|
|
if (!tok->valueType())
|
|
continue;
|
|
if (tok->valueType()->pointer > 0)
|
|
continue;
|
|
if (tok->valueType()->type != ValueType::Type::CONTAINER && tok->valueType()->type != ValueType::Type::ITERATOR)
|
|
continue;
|
|
|
|
// warn if this is a conditional expression..
|
|
if (Token::Match(tok->astParent()->previous(), "if|while ("))
|
|
assignmentInCondition(tok);
|
|
else if (Token::Match(tok->astParent(), "%oror%|&&"))
|
|
assignmentInCondition(tok);
|
|
else if (Token::simpleMatch(tok->astParent(), "?") && tok == tok->astParent()->astOperand1())
|
|
assignmentInCondition(tok);
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckCondition::assignmentInCondition(const Token *eq)
|
|
{
|
|
std::string expr = eq ? eq->expressionString() : "x=y";
|
|
|
|
reportError(
|
|
eq,
|
|
Severity::style,
|
|
"assignmentInCondition",
|
|
"Suspicious assignment in condition. Condition '" + expr + "' is always true.",
|
|
CWE571,
|
|
Certainty::normal);
|
|
}
|
|
|
|
void CheckCondition::checkCompareValueOutOfTypeRange()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::style))
|
|
return;
|
|
|
|
if (mSettings->platform.type == Platform::Type::Native ||
|
|
mSettings->platform.type == Platform::Type::Unspecified)
|
|
return;
|
|
|
|
logChecker("CheckCondition::checkCompareValueOutOfTypeRange"); // style,platform
|
|
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
for (const Scope * scope : symbolDatabase->functionScopes) {
|
|
for (const Token* tok = scope->bodyStart; tok != scope->bodyEnd; tok = tok->next()) {
|
|
if (!tok->isComparisonOp() || !tok->isBinaryOp())
|
|
continue;
|
|
|
|
for (int i = 0; i < 2; ++i) {
|
|
const Token * const valueTok = (i == 0) ? tok->astOperand1() : tok->astOperand2();
|
|
const Token * const typeTok = valueTok->astSibling();
|
|
if (!valueTok->hasKnownIntValue() || !typeTok->valueType() || typeTok->valueType()->pointer)
|
|
continue;
|
|
if (valueTok->getKnownIntValue() < 0 && valueTok->valueType() && valueTok->valueType()->sign != ValueType::Sign::SIGNED)
|
|
continue;
|
|
if (valueTok->valueType() && valueTok->valueType()->isTypeEqual(typeTok->valueType()))
|
|
continue;
|
|
int bits = 0;
|
|
switch (typeTok->valueType()->type) {
|
|
case ValueType::Type::BOOL:
|
|
bits = 1;
|
|
break;
|
|
case ValueType::Type::CHAR:
|
|
bits = mSettings->platform.char_bit;
|
|
break;
|
|
case ValueType::Type::SHORT:
|
|
bits = mSettings->platform.short_bit;
|
|
break;
|
|
case ValueType::Type::INT:
|
|
bits = mSettings->platform.int_bit;
|
|
break;
|
|
case ValueType::Type::LONG:
|
|
bits = mSettings->platform.long_bit;
|
|
break;
|
|
case ValueType::Type::LONGLONG:
|
|
bits = mSettings->platform.long_long_bit;
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
if (bits == 0 || bits >= 64)
|
|
continue;
|
|
|
|
const auto typeMinValue = (typeTok->valueType()->sign == ValueType::Sign::UNSIGNED) ? 0 : (-(1LL << (bits-1)));
|
|
const auto unsignedTypeMaxValue = (1LL << bits) - 1LL;
|
|
long long typeMaxValue;
|
|
if (typeTok->valueType()->sign != ValueType::Sign::SIGNED)
|
|
typeMaxValue = unsignedTypeMaxValue;
|
|
else if (bits >= mSettings->platform.int_bit && (!valueTok->valueType() || valueTok->valueType()->sign != ValueType::Sign::SIGNED))
|
|
typeMaxValue = unsignedTypeMaxValue;
|
|
else
|
|
typeMaxValue = unsignedTypeMaxValue / 2;
|
|
|
|
bool result{};
|
|
const auto kiv = valueTok->getKnownIntValue();
|
|
if (tok->str() == "==")
|
|
result = false;
|
|
else if (tok->str() == "!=")
|
|
result = true;
|
|
else if (tok->str()[0] == '>' && i == 0)
|
|
// num > var
|
|
result = (kiv > 0);
|
|
else if (tok->str()[0] == '>' && i == 1)
|
|
// var > num
|
|
result = (kiv < 0);
|
|
else if (tok->str()[0] == '<' && i == 0)
|
|
// num < var
|
|
result = (kiv < 0);
|
|
else if (tok->str()[0] == '<' && i == 1)
|
|
// var < num
|
|
result = (kiv > 0);
|
|
|
|
bool error = false;
|
|
if (kiv < typeMinValue || kiv > typeMaxValue) {
|
|
error = true;
|
|
} else {
|
|
switch (i) {
|
|
case 0: // num cmp var
|
|
if (kiv == typeMinValue) {
|
|
if (tok->str() == "<=") {
|
|
result = true;
|
|
error = true;
|
|
} else if (tok->str() == ">")
|
|
error = true;
|
|
}
|
|
else if (kiv == typeMaxValue && (tok->str() == ">=" || tok->str() == "<")) {
|
|
error = true;
|
|
}
|
|
break;
|
|
case 1: // var cmp num
|
|
if (kiv == typeMinValue) {
|
|
if (tok->str() == ">=") {
|
|
result = true;
|
|
error = true;
|
|
} else if (tok->str() == "<")
|
|
error = true;
|
|
}
|
|
else if (kiv == typeMaxValue && (tok->str() == "<=" || tok->str() == ">")) {
|
|
error = true;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
if (error)
|
|
compareValueOutOfTypeRangeError(valueTok, typeTok->valueType()->str(), kiv, result);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckCondition::compareValueOutOfTypeRangeError(const Token *comparison, const std::string &type, long long value, bool result)
|
|
{
|
|
reportError(
|
|
comparison,
|
|
Severity::style,
|
|
"compareValueOutOfTypeRangeError",
|
|
"Comparing expression of type '" + type + "' against value " + std::to_string(value) + ". Condition is always " + bool_to_string(result) + ".",
|
|
CWE398,
|
|
Certainty::normal);
|
|
}
|