3605 lines
166 KiB
C++
3605 lines
166 KiB
C++
/*
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* Cppcheck - A tool for static C/C++ code analysis
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* Copyright (C) 2007-2021 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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#include "checkother.h"
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#include "checkuninitvar.h" // CheckUninitVar::isVariableUsage
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#include "astutils.h"
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#include "library.h"
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#include "mathlib.h"
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#include "settings.h"
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#include "standards.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 "valueflow.h"
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#include <algorithm> // find_if()
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#include <list>
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#include <map>
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#include <utility>
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#include <cctype>
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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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CheckOther instance;
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}
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static const struct CWE CWE128(128U); // Wrap-around Error
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static const struct CWE CWE131(131U); // Incorrect Calculation of Buffer Size
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static const struct CWE CWE197(197U); // Numeric Truncation Error
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static const struct CWE CWE362(362U); // Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
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static const struct CWE CWE369(369U); // Divide By Zero
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static const struct CWE CWE398(398U); // Indicator of Poor Code Quality
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static const struct CWE CWE475(475U); // Undefined Behavior for Input to API
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static const struct CWE CWE482(482U); // Comparing instead of Assigning
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static const struct CWE CWE561(561U); // Dead Code
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static const struct CWE CWE563(563U); // Assignment to Variable without Use ('Unused Variable')
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static const struct CWE CWE570(570U); // Expression is Always False
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static const struct CWE CWE571(571U); // Expression is Always True
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static const struct CWE CWE672(672U); // Operation on a Resource after Expiration or Release
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static const struct CWE CWE628(628U); // Function Call with Incorrectly Specified Arguments
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static const struct CWE CWE683(683U); // Function Call With Incorrect Order of Arguments
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static const struct CWE CWE686(686U); // Function Call With Incorrect Argument Type
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static const struct CWE CWE704(704U); // Incorrect Type Conversion or Cast
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static const struct CWE CWE758(758U); // Reliance on Undefined, Unspecified, or Implementation-Defined Behavior
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static const struct CWE CWE768(768U); // Incorrect Short Circuit Evaluation
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static const struct CWE CWE783(783U); // Operator Precedence Logic Error
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//----------------------------------------------------------------------------------
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// The return value of fgetc(), getc(), ungetc(), getchar() etc. is an integer value.
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// If this return value is stored in a character variable and then compared
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// to EOF, which is an integer, the comparison maybe be false.
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//
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// Reference:
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// - Ticket #160
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// - http://www.cplusplus.com/reference/cstdio/fgetc/
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// - http://www.cplusplus.com/reference/cstdio/getc/
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// - http://www.cplusplus.com/reference/cstdio/getchar/
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// - http://www.cplusplus.com/reference/cstdio/ungetc/ ...
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//----------------------------------------------------------------------------------
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void CheckOther::checkCastIntToCharAndBack()
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{
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if (!mSettings->severity.isEnabled(Severity::warning))
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return;
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const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
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for (const Scope * scope : symbolDatabase->functionScopes) {
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std::map<int, std::string> vars;
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for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
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// Quick check to see if any of the matches below have any chances
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if (!Token::Match(tok, "%var%|EOF %comp%|="))
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continue;
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if (Token::Match(tok, "%var% = fclose|fflush|fputc|fputs|fscanf|getchar|getc|fgetc|putchar|putc|puts|scanf|sscanf|ungetc (")) {
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const Variable *var = tok->variable();
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if (var && var->typeEndToken()->str() == "char" && !var->typeEndToken()->isSigned()) {
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vars[tok->varId()] = tok->strAt(2);
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}
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} else if (Token::Match(tok, "EOF %comp% ( %var% = fclose|fflush|fputc|fputs|fscanf|getchar|getc|fgetc|putchar|putc|puts|scanf|sscanf|ungetc (")) {
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tok = tok->tokAt(3);
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const Variable *var = tok->variable();
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if (var && var->typeEndToken()->str() == "char" && !var->typeEndToken()->isSigned()) {
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checkCastIntToCharAndBackError(tok, tok->strAt(2));
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}
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} else if (mTokenizer->isCPP() && (Token::Match(tok, "EOF %comp% ( %var% = std :: cin . get (") || Token::Match(tok, "EOF %comp% ( %var% = cin . get ("))) {
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tok = tok->tokAt(3);
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const Variable *var = tok->variable();
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if (var && var->typeEndToken()->str() == "char" && !var->typeEndToken()->isSigned()) {
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checkCastIntToCharAndBackError(tok, "cin.get");
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}
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} else if (mTokenizer->isCPP() && (Token::Match(tok, "%var% = std :: cin . get (") || Token::Match(tok, "%var% = cin . get ("))) {
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const Variable *var = tok->variable();
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if (var && var->typeEndToken()->str() == "char" && !var->typeEndToken()->isSigned()) {
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vars[tok->varId()] = "cin.get";
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}
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} else if (Token::Match(tok, "%var% %comp% EOF")) {
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if (vars.find(tok->varId()) != vars.end()) {
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checkCastIntToCharAndBackError(tok, vars[tok->varId()]);
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}
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} else if (Token::Match(tok, "EOF %comp% %var%")) {
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tok = tok->tokAt(2);
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if (vars.find(tok->varId()) != vars.end()) {
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checkCastIntToCharAndBackError(tok, vars[tok->varId()]);
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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 CheckOther::checkCastIntToCharAndBackError(const Token *tok, const std::string &strFunctionName)
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{
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reportError(
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tok,
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Severity::warning,
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"checkCastIntToCharAndBack",
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"$symbol:" + strFunctionName + "\n"
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"Storing $symbol() return value in char variable and then comparing with EOF.\n"
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"When saving $symbol() return value in char variable there is loss of precision. "
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" When $symbol() returns EOF this value is truncated. Comparing the char "
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"variable with EOF can have unexpected results. For instance a loop \"while (EOF != (c = $symbol());\" "
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"loops forever on some compilers/platforms and on other compilers/platforms it will stop "
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"when the file contains a matching character.", CWE197, Certainty::normal
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);
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}
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//---------------------------------------------------------------------------
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// Clarify calculation precedence for ternary operators.
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//---------------------------------------------------------------------------
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void CheckOther::clarifyCalculation()
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{
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if (!mSettings->severity.isEnabled(Severity::style))
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return;
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const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
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for (const Scope * scope : symbolDatabase->functionScopes) {
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for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
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// ? operator where lhs is arithmetical expression
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if (tok->str() != "?" || !tok->astOperand1() || !tok->astOperand1()->isCalculation())
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continue;
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if (!tok->astOperand1()->isArithmeticalOp() && tok->astOperand1()->tokType() != Token::eBitOp)
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continue;
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// non-pointer calculation in lhs and pointer in rhs => no clarification is needed
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if (tok->astOperand1()->isBinaryOp() && Token::Match(tok->astOperand1(), "%or%|&|%|*|/") && tok->astOperand2()->valueType() && tok->astOperand2()->valueType()->pointer > 0)
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continue;
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// bit operation in lhs and char literals in rhs => probably no mistake
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if (tok->astOperand1()->tokType() == Token::eBitOp && Token::Match(tok->astOperand2()->astOperand1(), "%char%") && Token::Match(tok->astOperand2()->astOperand2(), "%char%"))
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continue;
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// 2nd operand in lhs has known integer value => probably no mistake
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if (tok->astOperand1()->isBinaryOp() && tok->astOperand1()->astOperand2()->hasKnownIntValue()) {
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const Token *op = tok->astOperand1()->astOperand2();
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if (op->isNumber())
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continue;
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if (op->valueType() && op->valueType()->isEnum())
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continue;
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}
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// Is code clarified by parentheses already?
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const Token *tok2 = tok->astOperand1();
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for (; tok2; tok2 = tok2->next()) {
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if (tok2->str() == "(")
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tok2 = tok2->link();
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else if (tok2->str() == ")")
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break;
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else if (tok2->str() == "?") {
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clarifyCalculationError(tok, tok->astOperand1()->str());
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break;
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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 CheckOther::clarifyCalculationError(const Token *tok, const std::string &op)
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{
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// suspicious calculation
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const std::string calc("'a" + op + "b?c:d'");
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// recommended calculation #1
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const std::string s1("'(a" + op + "b)?c:d'");
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// recommended calculation #2
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const std::string s2("'a" + op + "(b?c:d)'");
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reportError(tok,
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Severity::style,
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"clarifyCalculation",
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"Clarify calculation precedence for '" + op + "' and '?'.\n"
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"Suspicious calculation. Please use parentheses to clarify the code. "
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"The code '" + calc + "' should be written as either '" + s1 + "' or '" + s2 + "'.", CWE783, Certainty::normal);
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}
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//---------------------------------------------------------------------------
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// Clarify (meaningless) statements like *foo++; with parentheses.
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//---------------------------------------------------------------------------
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void CheckOther::clarifyStatement()
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{
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if (!mSettings->severity.isEnabled(Severity::warning))
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return;
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const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
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for (const Scope * scope : symbolDatabase->functionScopes) {
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for (const Token* tok = scope->bodyStart; tok && tok != scope->bodyEnd; tok = tok->next()) {
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if (Token::Match(tok, "* %name%") && tok->astOperand1()) {
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const Token *tok2 = tok->previous();
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while (tok2 && tok2->str() == "*")
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tok2 = tok2->previous();
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if (tok2 && !tok2->astParent() && Token::Match(tok2, "[{};]")) {
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tok2 = tok->astOperand1();
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if (Token::Match(tok2, "++|-- [;,]"))
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clarifyStatementError(tok2);
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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 CheckOther::clarifyStatementError(const Token *tok)
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{
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reportError(tok, Severity::warning, "clarifyStatement", "In expression like '*A++' the result of '*' is unused. Did you intend to write '(*A)++;'?\n"
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"A statement like '*A++;' might not do what you intended. Postfix 'operator++' is executed before 'operator*'. "
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"Thus, the dereference is meaningless. Did you intend to write '(*A)++;'?", CWE783, Certainty::normal);
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}
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//---------------------------------------------------------------------------
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// Check for suspicious occurrences of 'if(); {}'.
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//---------------------------------------------------------------------------
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void CheckOther::checkSuspiciousSemicolon()
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{
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if (!mSettings->certainty.isEnabled(Certainty::inconclusive) || !mSettings->severity.isEnabled(Severity::warning))
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return;
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const SymbolDatabase* const symbolDatabase = mTokenizer->getSymbolDatabase();
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// Look for "if(); {}", "for(); {}" or "while(); {}"
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for (const Scope &scope : symbolDatabase->scopeList) {
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if (scope.type == Scope::eIf || scope.type == Scope::eElse || scope.type == Scope::eWhile || scope.type == Scope::eFor) {
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// Ensure the semicolon is at the same line number as the if/for/while statement
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// and the {..} block follows it without an extra empty line.
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if (Token::simpleMatch(scope.bodyStart, "{ ; } {") &&
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scope.bodyStart->previous()->linenr() == scope.bodyStart->tokAt(2)->linenr() &&
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scope.bodyStart->linenr()+1 >= scope.bodyStart->tokAt(3)->linenr() &&
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!scope.bodyStart->tokAt(3)->isExpandedMacro()) {
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suspiciousSemicolonError(scope.classDef);
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}
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}
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}
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}
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void CheckOther::suspiciousSemicolonError(const Token* tok)
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{
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reportError(tok, Severity::warning, "suspiciousSemicolon",
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"Suspicious use of ; at the end of '" + (tok ? tok->str() : std::string()) + "' statement.", CWE398, Certainty::normal);
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}
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//---------------------------------------------------------------------------
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// For C++ code, warn if C-style casts are used on pointer types
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//---------------------------------------------------------------------------
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void CheckOther::warningOldStylePointerCast()
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{
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// Only valid on C++ code
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if (!mSettings->severity.isEnabled(Severity::style) || !mTokenizer->isCPP())
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return;
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const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
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for (const Scope * scope : symbolDatabase->functionScopes) {
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const Token* tok;
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if (scope->function && scope->function->isConstructor())
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tok = scope->classDef;
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else
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tok = scope->bodyStart;
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for (; tok && tok != scope->bodyEnd; tok = tok->next()) {
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// Old style pointer casting..
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if (!Token::Match(tok, "( const|volatile| const|volatile| %type% * const| ) (| %name%|%num%|%bool%|%char%|%str%"))
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continue;
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// skip first "const" in "const Type* const"
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while (Token::Match(tok->next(), "const|volatile"))
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tok = tok->next();
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const Token* typeTok = tok->next();
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// skip second "const" in "const Type* const"
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if (tok->strAt(3) == "const")
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tok = tok->next();
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const Token *p = tok->tokAt(4);
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if (p->hasKnownIntValue() && p->values().front().intvalue==0) // Casting nullpointers is safe
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continue;
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// Is "type" a class?
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if (typeTok->type())
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cstyleCastError(tok);
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}
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}
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}
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void CheckOther::cstyleCastError(const Token *tok)
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{
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reportError(tok, Severity::style, "cstyleCast",
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"C-style pointer casting\n"
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"C-style pointer casting detected. C++ offers four different kinds of casts as replacements: "
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"static_cast, const_cast, dynamic_cast and reinterpret_cast. A C-style cast could evaluate to "
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"any of those automatically, thus it is considered safer if the programmer explicitly states "
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"which kind of cast is expected. See also: https://www.securecoding.cert.org/confluence/display/cplusplus/EXP05-CPP.+Do+not+use+C-style+casts.", CWE398, Certainty::normal);
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}
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//---------------------------------------------------------------------------
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// float* f; double* d = (double*)f; <-- Pointer cast to a type with an incompatible binary data representation
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//---------------------------------------------------------------------------
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void CheckOther::invalidPointerCast()
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{
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if (!mSettings->severity.isEnabled(Severity::portability))
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return;
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const bool printInconclusive = mSettings->certainty.isEnabled(Certainty::inconclusive);
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const SymbolDatabase* const symbolDatabase = mTokenizer->getSymbolDatabase();
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for (const Scope * scope : symbolDatabase->functionScopes) {
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for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
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const Token* toTok = nullptr;
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const Token* fromTok = nullptr;
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// Find cast
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if (Token::Match(tok, "( const|volatile| const|volatile| %type% %type%| const| * )")) {
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toTok = tok;
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fromTok = tok->astOperand1();
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} else if (Token::simpleMatch(tok, "reinterpret_cast <") && tok->linkAt(1)) {
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toTok = tok->linkAt(1)->next();
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fromTok = toTok->astOperand2();
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}
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if (!fromTok)
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continue;
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const ValueType* fromType = fromTok->valueType();
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const ValueType* toType = toTok->valueType();
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if (!fromType || !toType || !fromType->pointer || !toType->pointer)
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continue;
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if (fromType->type != toType->type && fromType->type >= ValueType::Type::BOOL && toType->type >= ValueType::Type::BOOL && (toType->type != ValueType::Type::CHAR || printInconclusive)) {
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if (toType->isIntegral() && fromType->isIntegral())
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continue;
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invalidPointerCastError(tok, fromType->str(), toType->str(), toType->type == ValueType::Type::CHAR, toType->isIntegral());
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}
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}
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}
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}
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void CheckOther::invalidPointerCastError(const Token* tok, const std::string& from, const std::string& to, bool inconclusive, bool toIsInt)
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{
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if (toIsInt) { // If we cast something to int*, this can be useful to play with its binary data representation
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reportError(tok, Severity::portability, "invalidPointerCast", "Casting from " + from + " to " + to + " is not portable due to different binary data representations on different platforms.", CWE704, inconclusive ? Certainty::inconclusive : Certainty::normal);
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} else
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reportError(tok, Severity::portability, "invalidPointerCast", "Casting between " + from + " and " + to + " which have an incompatible binary data representation.", CWE704, Certainty::normal);
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}
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//---------------------------------------------------------------------------
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// This check detects errors on POSIX systems, when a pipe command called
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// with a wrong dimensioned file descriptor array. The pipe command requires
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// exactly an integer array of dimension two as parameter.
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//
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// References:
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// - http://linux.die.net/man/2/pipe
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// - ticket #3521
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//---------------------------------------------------------------------------
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void CheckOther::checkPipeParameterSize()
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{
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if (!mSettings->posix())
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return;
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const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
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for (const Scope * scope : symbolDatabase->functionScopes) {
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for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
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if (Token::Match(tok, "pipe ( %var% )") ||
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Token::Match(tok, "pipe2 ( %var% ,")) {
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const Token * const varTok = tok->tokAt(2);
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const Variable *var = varTok->variable();
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MathLib::bigint dim;
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if (var && var->isArray() && !var->isArgument() && ((dim=var->dimension(0U)) < 2)) {
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const std::string strDim = MathLib::toString(dim);
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checkPipeParameterSizeError(varTok,varTok->str(), strDim);
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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 CheckOther::checkPipeParameterSizeError(const Token *tok, const std::string &strVarName, const std::string &strDim)
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{
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reportError(tok, Severity::error,
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"wrongPipeParameterSize",
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"$symbol:" + strVarName + "\n"
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"Buffer '$symbol' must have size of 2 integers if used as parameter of pipe().\n"
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"The pipe()/pipe2() system command takes an argument, which is an array of exactly two integers.\n"
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"The variable '$symbol' is an array of size " + strDim + ", which does not match.", CWE686, Certainty::safe);
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}
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//---------------------------------------------------------------------------
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// Detect redundant assignments: x = 0; x = 4;
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//---------------------------------------------------------------------------
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void CheckOther::checkRedundantAssignment()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::style))
|
|
return;
|
|
const SymbolDatabase* symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
for (const Scope *scope : symbolDatabase->functionScopes) {
|
|
if (!scope->bodyStart)
|
|
continue;
|
|
for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
|
|
if (Token::simpleMatch(tok, "] ("))
|
|
// todo: handle lambdas
|
|
break;
|
|
if (Token::simpleMatch(tok, "try {"))
|
|
// todo: check try blocks
|
|
tok = tok->linkAt(1);
|
|
if ((tok->isAssignmentOp() || Token::Match(tok, "++|--")) && tok->astOperand1()) {
|
|
if (tok->astParent())
|
|
continue;
|
|
|
|
// Do not warn about redundant initialization when rhs is trivial
|
|
// TODO : do not simplify the variable declarations
|
|
bool isInitialization = false;
|
|
if (Token::Match(tok->tokAt(-2), "; %var% =") && tok->tokAt(-2)->isSplittedVarDeclEq()) {
|
|
isInitialization = true;
|
|
bool trivial = true;
|
|
visitAstNodes(tok->astOperand2(),
|
|
[&](const Token *rhs) {
|
|
if (Token::simpleMatch(rhs, "{ 0 }"))
|
|
return ChildrenToVisit::none;
|
|
if (Token::Match(rhs, "%str%|%num%|%name%") && !rhs->varId())
|
|
return ChildrenToVisit::none;
|
|
if (Token::Match(rhs, ":: %name%") && rhs->hasKnownIntValue())
|
|
return ChildrenToVisit::none;
|
|
if (rhs->isCast())
|
|
return ChildrenToVisit::op2;
|
|
trivial = false;
|
|
return ChildrenToVisit::done;
|
|
});
|
|
if (trivial)
|
|
continue;
|
|
}
|
|
|
|
const Token* rhs = tok->astOperand2();
|
|
// Do not warn about assignment with 0 / NULL
|
|
if ((rhs && MathLib::isNullValue(rhs->str())) || isNullOperand(rhs))
|
|
continue;
|
|
|
|
if (tok->astOperand1()->variable() && tok->astOperand1()->variable()->isReference())
|
|
// todo: check references
|
|
continue;
|
|
|
|
if (tok->astOperand1()->variable() && tok->astOperand1()->variable()->isStatic())
|
|
// todo: check static variables
|
|
continue;
|
|
|
|
// If there is a custom assignment operator => this is inconclusive
|
|
bool inconclusive = false;
|
|
if (mTokenizer->isCPP() && tok->astOperand1()->valueType() && tok->astOperand1()->valueType()->typeScope) {
|
|
const std::string op = "operator" + tok->str();
|
|
for (const Function &f : tok->astOperand1()->valueType()->typeScope->functionList) {
|
|
if (f.name() == op) {
|
|
inconclusive = true;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
if (inconclusive && !mSettings->certainty.isEnabled(Certainty::inconclusive))
|
|
continue;
|
|
|
|
FwdAnalysis fwdAnalysis(mTokenizer->isCPP(), mSettings->library);
|
|
if (fwdAnalysis.hasOperand(tok->astOperand2(), tok->astOperand1()))
|
|
continue;
|
|
|
|
// Is there a redundant assignment?
|
|
const Token *start;
|
|
if (tok->isAssignmentOp())
|
|
start = tok->next();
|
|
else
|
|
start = tok->findExpressionStartEndTokens().second->next();
|
|
|
|
// Get next assignment..
|
|
const Token *nextAssign = fwdAnalysis.reassign(tok->astOperand1(), start, scope->bodyEnd);
|
|
|
|
if (!nextAssign)
|
|
continue;
|
|
|
|
// there is redundant assignment. Is there a case between the assignments?
|
|
bool hasCase = false;
|
|
for (const Token *tok2 = tok; tok2 != nextAssign; tok2 = tok2->next()) {
|
|
if (tok2->str() == "break" || tok2->str() == "return")
|
|
break;
|
|
if (tok2->str() == "case") {
|
|
hasCase = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
// warn
|
|
if (hasCase)
|
|
redundantAssignmentInSwitchError(tok, nextAssign, tok->astOperand1()->expressionString());
|
|
else if (isInitialization)
|
|
redundantInitializationError(tok, nextAssign, tok->astOperand1()->expressionString(), inconclusive);
|
|
else
|
|
redundantAssignmentError(tok, nextAssign, tok->astOperand1()->expressionString(), inconclusive);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckOther::redundantCopyError(const Token *tok1, const Token* tok2, const std::string& var)
|
|
{
|
|
const std::list<const Token *> callstack = { tok1, tok2 };
|
|
reportError(callstack, Severity::performance, "redundantCopy",
|
|
"$symbol:" + var + "\n"
|
|
"Buffer '$symbol' is being written before its old content has been used.", CWE563, Certainty::normal);
|
|
}
|
|
|
|
void CheckOther::redundantCopyInSwitchError(const Token *tok1, const Token* tok2, const std::string &var)
|
|
{
|
|
const std::list<const Token *> callstack = { tok1, tok2 };
|
|
reportError(callstack, Severity::style, "redundantCopyInSwitch",
|
|
"$symbol:" + var + "\n"
|
|
"Buffer '$symbol' is being written before its old content has been used. 'break;' missing?", CWE563, Certainty::normal);
|
|
}
|
|
|
|
void CheckOther::redundantAssignmentError(const Token *tok1, const Token* tok2, const std::string& var, bool inconclusive)
|
|
{
|
|
const ErrorPath errorPath = { ErrorPathItem(tok1, var + " is assigned"), ErrorPathItem(tok2, var + " is overwritten") };
|
|
if (inconclusive)
|
|
reportError(errorPath, Severity::style, "redundantAssignment",
|
|
"$symbol:" + var + "\n"
|
|
"Variable '$symbol' is reassigned a value before the old one has been used if variable is no semaphore variable.\n"
|
|
"Variable '$symbol' is reassigned a value before the old one has been used. Make sure that this variable is not used like a semaphore in a threading environment before simplifying this code.", CWE563, Certainty::inconclusive);
|
|
else
|
|
reportError(errorPath, Severity::style, "redundantAssignment",
|
|
"$symbol:" + var + "\n"
|
|
"Variable '$symbol' is reassigned a value before the old one has been used.", CWE563, Certainty::normal);
|
|
}
|
|
|
|
void CheckOther::redundantInitializationError(const Token *tok1, const Token* tok2, const std::string& var, bool inconclusive)
|
|
{
|
|
const ErrorPath errorPath = { ErrorPathItem(tok1, var + " is initialized"), ErrorPathItem(tok2, var + " is overwritten") };
|
|
reportError(errorPath, Severity::style, "redundantInitialization",
|
|
"$symbol:" + var + "\nRedundant initialization for '$symbol'. The initialized value is overwritten before it is read.",
|
|
CWE563,
|
|
inconclusive ? Certainty::inconclusive : Certainty::normal);
|
|
}
|
|
|
|
void CheckOther::redundantAssignmentInSwitchError(const Token *tok1, const Token* tok2, const std::string &var)
|
|
{
|
|
const ErrorPath errorPath = { ErrorPathItem(tok1, "$symbol is assigned"), ErrorPathItem(tok2, "$symbol is overwritten") };
|
|
reportError(errorPath, Severity::style, "redundantAssignInSwitch",
|
|
"$symbol:" + var + "\n"
|
|
"Variable '$symbol' is reassigned a value before the old one has been used. 'break;' missing?", CWE563, Certainty::normal);
|
|
}
|
|
|
|
|
|
//---------------------------------------------------------------------------
|
|
// switch (x)
|
|
// {
|
|
// case 2:
|
|
// y = a; // <- this assignment is redundant
|
|
// case 3:
|
|
// y = b; // <- case 2 falls through and sets y twice
|
|
// }
|
|
//---------------------------------------------------------------------------
|
|
static inline bool isFunctionOrBreakPattern(const Token *tok)
|
|
{
|
|
if (Token::Match(tok, "%name% (") || Token::Match(tok, "break|continue|return|exit|goto|throw"))
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
void CheckOther::checkRedundantAssignmentInSwitch()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::warning))
|
|
return;
|
|
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
|
|
// Find the beginning of a switch. E.g.:
|
|
// switch (var) { ...
|
|
for (const Scope &switchScope : symbolDatabase->scopeList) {
|
|
if (switchScope.type != Scope::eSwitch || !switchScope.bodyStart)
|
|
continue;
|
|
|
|
// Check the contents of the switch statement
|
|
std::map<int, const Token*> varsWithBitsSet;
|
|
std::map<int, std::string> bitOperations;
|
|
|
|
for (const Token *tok2 = switchScope.bodyStart->next(); tok2 != switchScope.bodyEnd; tok2 = tok2->next()) {
|
|
if (tok2->str() == "{") {
|
|
// Inside a conditional or loop. Don't mark variable accesses as being redundant. E.g.:
|
|
// case 3: b = 1;
|
|
// case 4: if (a) { b = 2; } // Doesn't make the b=1 redundant because it's conditional
|
|
if (Token::Match(tok2->previous(), ")|else {") && tok2->link()) {
|
|
const Token* endOfConditional = tok2->link();
|
|
for (const Token* tok3 = tok2; tok3 != endOfConditional; tok3 = tok3->next()) {
|
|
if (tok3->varId() != 0) {
|
|
varsWithBitsSet.erase(tok3->varId());
|
|
bitOperations.erase(tok3->varId());
|
|
} else if (isFunctionOrBreakPattern(tok3)) {
|
|
varsWithBitsSet.clear();
|
|
bitOperations.clear();
|
|
}
|
|
}
|
|
tok2 = endOfConditional;
|
|
}
|
|
}
|
|
|
|
// Variable assignment. Report an error if it's assigned to twice before a break. E.g.:
|
|
// case 3: b = 1; // <== redundant
|
|
// case 4: b = 2;
|
|
|
|
if (Token::Match(tok2->previous(), ";|{|}|: %var% = %any% ;")) {
|
|
varsWithBitsSet.erase(tok2->varId());
|
|
bitOperations.erase(tok2->varId());
|
|
}
|
|
|
|
// Bitwise operation. Report an error if it's performed twice before a break. E.g.:
|
|
// case 3: b |= 1; // <== redundant
|
|
// case 4: b |= 1;
|
|
else if (Token::Match(tok2->previous(), ";|{|}|: %var% %assign% %num% ;") &&
|
|
(tok2->strAt(1) == "|=" || tok2->strAt(1) == "&=") &&
|
|
Token::Match(tok2->next()->astOperand2(), "%num%")) {
|
|
const std::string bitOp = tok2->strAt(1)[0] + tok2->strAt(2);
|
|
const std::map<int, const Token*>::const_iterator i2 = varsWithBitsSet.find(tok2->varId());
|
|
|
|
// This variable has not had a bit operation performed on it yet, so just make a note of it
|
|
if (i2 == varsWithBitsSet.end()) {
|
|
varsWithBitsSet[tok2->varId()] = tok2;
|
|
bitOperations[tok2->varId()] = bitOp;
|
|
}
|
|
|
|
// The same bit operation has been performed on the same variable twice, so report an error
|
|
else if (bitOperations[tok2->varId()] == bitOp)
|
|
redundantBitwiseOperationInSwitchError(i2->second, i2->second->str());
|
|
|
|
// A different bit operation was performed on the variable, so clear it
|
|
else {
|
|
varsWithBitsSet.erase(tok2->varId());
|
|
bitOperations.erase(tok2->varId());
|
|
}
|
|
}
|
|
|
|
// Bitwise operation. Report an error if it's performed twice before a break. E.g.:
|
|
// case 3: b = b | 1; // <== redundant
|
|
// case 4: b = b | 1;
|
|
else if (Token::Match(tok2->previous(), ";|{|}|: %var% = %name% %or%|& %num% ;") &&
|
|
tok2->varId() == tok2->tokAt(2)->varId()) {
|
|
const std::string bitOp = tok2->strAt(3) + tok2->strAt(4);
|
|
const std::map<int, const Token*>::const_iterator i2 = varsWithBitsSet.find(tok2->varId());
|
|
|
|
// This variable has not had a bit operation performed on it yet, so just make a note of it
|
|
if (i2 == varsWithBitsSet.end()) {
|
|
varsWithBitsSet[tok2->varId()] = tok2;
|
|
bitOperations[tok2->varId()] = bitOp;
|
|
}
|
|
|
|
// The same bit operation has been performed on the same variable twice, so report an error
|
|
else if (bitOperations[tok2->varId()] == bitOp)
|
|
redundantBitwiseOperationInSwitchError(i2->second, i2->second->str());
|
|
|
|
// A different bit operation was performed on the variable, so clear it
|
|
else {
|
|
varsWithBitsSet.erase(tok2->varId());
|
|
bitOperations.erase(tok2->varId());
|
|
}
|
|
}
|
|
|
|
// Not a simple assignment so there may be good reason if this variable is assigned to twice. E.g.:
|
|
// case 3: b = 1;
|
|
// case 4: b++;
|
|
else if (tok2->varId() != 0 && tok2->strAt(1) != "|" && tok2->strAt(1) != "&") {
|
|
varsWithBitsSet.erase(tok2->varId());
|
|
bitOperations.erase(tok2->varId());
|
|
}
|
|
|
|
// Reset our record of assignments if there is a break or function call. E.g.:
|
|
// case 3: b = 1; break;
|
|
if (isFunctionOrBreakPattern(tok2)) {
|
|
varsWithBitsSet.clear();
|
|
bitOperations.clear();
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckOther::redundantBitwiseOperationInSwitchError(const Token *tok, const std::string &varname)
|
|
{
|
|
reportError(tok, Severity::style,
|
|
"redundantBitwiseOperationInSwitch",
|
|
"$symbol:" + varname + "\n"
|
|
"Redundant bitwise operation on '$symbol' in 'switch' statement. 'break;' missing?");
|
|
}
|
|
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Check for statements like case A||B: in switch()
|
|
//---------------------------------------------------------------------------
|
|
void CheckOther::checkSuspiciousCaseInSwitch()
|
|
{
|
|
if (!mSettings->certainty.isEnabled(Certainty::inconclusive) || !mSettings->severity.isEnabled(Severity::warning))
|
|
return;
|
|
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
|
|
for (const Scope & scope : symbolDatabase->scopeList) {
|
|
if (scope.type != Scope::eSwitch)
|
|
continue;
|
|
|
|
for (const Token* tok = scope.bodyStart->next(); tok != scope.bodyEnd; tok = tok->next()) {
|
|
if (tok->str() == "case") {
|
|
const Token* finding = nullptr;
|
|
for (const Token* tok2 = tok->next(); tok2; tok2 = tok2->next()) {
|
|
if (tok2->str() == ":")
|
|
break;
|
|
if (Token::Match(tok2, "[;}{]"))
|
|
break;
|
|
|
|
if (tok2->str() == "?")
|
|
finding = nullptr;
|
|
else if (Token::Match(tok2, "&&|%oror%"))
|
|
finding = tok2;
|
|
}
|
|
if (finding)
|
|
suspiciousCaseInSwitchError(finding, finding->str());
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckOther::suspiciousCaseInSwitchError(const Token* tok, const std::string& operatorString)
|
|
{
|
|
reportError(tok, Severity::warning, "suspiciousCase",
|
|
"Found suspicious case label in switch(). Operator '" + operatorString + "' probably doesn't work as intended.\n"
|
|
"Using an operator like '" + operatorString + "' in a case label is suspicious. Did you intend to use a bitwise operator, multiple case labels or if/else instead?", CWE398, Certainty::inconclusive);
|
|
}
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Find consecutive return, break, continue, goto or throw statements. e.g.:
|
|
// break; break;
|
|
// Detect dead code, that follows such a statement. e.g.:
|
|
// return(0); foo();
|
|
//---------------------------------------------------------------------------
|
|
void CheckOther::checkUnreachableCode()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::style))
|
|
return;
|
|
const bool printInconclusive = mSettings->certainty.isEnabled(Certainty::inconclusive);
|
|
const SymbolDatabase* symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
for (const Scope * scope : symbolDatabase->functionScopes) {
|
|
for (const Token* tok = scope->bodyStart; tok && tok != scope->bodyEnd; tok = tok->next()) {
|
|
const Token* secondBreak = nullptr;
|
|
const Token* labelName = nullptr;
|
|
if (tok->link() && Token::Match(tok, "(|[|<"))
|
|
tok = tok->link();
|
|
else if (Token::Match(tok, "break|continue ;"))
|
|
secondBreak = tok->tokAt(2);
|
|
else if (Token::Match(tok, "[;{}:] return|throw") && tok->next()->isKeyword()) {
|
|
if (Token::simpleMatch(tok->astParent(), "?"))
|
|
continue;
|
|
tok = tok->next(); // tok should point to return or throw
|
|
for (const Token *tok2 = tok->next(); tok2; tok2 = tok2->next()) {
|
|
if (tok2->str() == "(" || tok2->str() == "{")
|
|
tok2 = tok2->link();
|
|
if (tok2->str() == ";") {
|
|
secondBreak = tok2->next();
|
|
break;
|
|
}
|
|
}
|
|
} else if (Token::Match(tok, "goto %any% ;")) {
|
|
secondBreak = tok->tokAt(3);
|
|
labelName = tok->next();
|
|
} else if (Token::Match(tok, "%name% (") && mSettings->library.isnoreturn(tok) && !Token::Match(tok->next()->astParent(), "?|:")) {
|
|
if ((!tok->function() || (tok->function()->token != tok && tok->function()->tokenDef != tok)) && tok->linkAt(1)->strAt(1) != "{")
|
|
secondBreak = tok->linkAt(1)->tokAt(2);
|
|
if (Token::simpleMatch(secondBreak, "return")) {
|
|
// clarification for tools that function returns
|
|
continue;
|
|
}
|
|
}
|
|
|
|
// Statements follow directly, no line between them. (#3383)
|
|
// TODO: Try to find a better way to avoid false positives due to preprocessor configurations.
|
|
const bool inconclusive = secondBreak && (secondBreak->linenr() - 1 > secondBreak->previous()->linenr());
|
|
|
|
if (secondBreak && (printInconclusive || !inconclusive)) {
|
|
if (Token::Match(secondBreak, "continue|goto|throw|return") && secondBreak->isKeyword()) {
|
|
duplicateBreakError(secondBreak, inconclusive);
|
|
tok = Token::findmatch(secondBreak, "[}:]");
|
|
} else if (secondBreak->str() == "break") { // break inside switch as second break statement should not issue a warning
|
|
if (tok->str() == "break") // If the previous was a break, too: Issue warning
|
|
duplicateBreakError(secondBreak, inconclusive);
|
|
else {
|
|
if (tok->scope()->type != Scope::eSwitch) // Check, if the enclosing scope is a switch
|
|
duplicateBreakError(secondBreak, inconclusive);
|
|
}
|
|
tok = Token::findmatch(secondBreak, "[}:]");
|
|
} else if (!Token::Match(secondBreak, "return|}|case|default") && secondBreak->strAt(1) != ":") { // TODO: No bailout for unconditional scopes
|
|
// If the goto label is followed by a loop construct in which the label is defined it's quite likely
|
|
// that the goto jump was intended to skip some code on the first loop iteration.
|
|
bool labelInFollowingLoop = false;
|
|
if (labelName && Token::Match(secondBreak, "while|do|for")) {
|
|
const Token *scope2 = Token::findsimplematch(secondBreak, "{");
|
|
if (scope2) {
|
|
for (const Token *tokIter = scope2; tokIter != scope2->link() && tokIter; tokIter = tokIter->next()) {
|
|
if (Token::Match(tokIter, "[;{}] %any% :") && labelName->str() == tokIter->strAt(1)) {
|
|
labelInFollowingLoop = true;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// hide FP for statements that just hide compiler warnings about unused function arguments
|
|
bool silencedCompilerWarningOnly = false;
|
|
const Token *silencedWarning = secondBreak;
|
|
for (;;) {
|
|
if (Token::Match(silencedWarning, "( void ) %name% ;")) {
|
|
silencedWarning = silencedWarning->tokAt(5);
|
|
continue;
|
|
} else if (silencedWarning && silencedWarning == scope->bodyEnd)
|
|
silencedCompilerWarningOnly = true;
|
|
|
|
break;
|
|
}
|
|
if (silencedWarning)
|
|
secondBreak = silencedWarning;
|
|
|
|
if (!labelInFollowingLoop && !silencedCompilerWarningOnly)
|
|
unreachableCodeError(secondBreak, inconclusive);
|
|
tok = Token::findmatch(secondBreak, "[}:]");
|
|
} else
|
|
tok = secondBreak;
|
|
|
|
if (!tok)
|
|
break;
|
|
tok = tok->previous(); // Will be advanced again by for loop
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckOther::duplicateBreakError(const Token *tok, bool inconclusive)
|
|
{
|
|
reportError(tok, Severity::style, "duplicateBreak",
|
|
"Consecutive return, break, continue, goto or throw statements are unnecessary.\n"
|
|
"Consecutive return, break, continue, goto or throw statements are unnecessary. "
|
|
"The second statement can never be executed, and so should be removed.", CWE561, inconclusive ? Certainty::inconclusive : Certainty::normal);
|
|
}
|
|
|
|
void CheckOther::unreachableCodeError(const Token *tok, bool inconclusive)
|
|
{
|
|
reportError(tok, Severity::style, "unreachableCode",
|
|
"Statements following return, break, continue, goto or throw will never be executed.", CWE561, inconclusive ? Certainty::inconclusive : Certainty::normal);
|
|
}
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Check scope of variables..
|
|
//---------------------------------------------------------------------------
|
|
void CheckOther::checkVariableScope()
|
|
{
|
|
if (mSettings->clang)
|
|
return;
|
|
|
|
if (!mSettings->severity.isEnabled(Severity::style))
|
|
return;
|
|
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
|
|
// In C it is common practice to declare local variables at the
|
|
// start of functions.
|
|
if (mSettings->daca && mTokenizer->isC())
|
|
return;
|
|
|
|
for (const Variable* var : symbolDatabase->variableList()) {
|
|
if (!var || !var->isLocal() || (!var->isPointer() && !var->isReference() && !var->typeStartToken()->isStandardType()))
|
|
continue;
|
|
|
|
if (var->isConst())
|
|
continue;
|
|
|
|
if (mTokenizer->hasIfdef(var->nameToken(), var->scope()->bodyEnd))
|
|
continue;
|
|
|
|
// reference of range for loop variable..
|
|
if (Token::Match(var->nameToken()->previous(), "& %var% = %var% .")) {
|
|
const Token *otherVarToken = var->nameToken()->tokAt(2);
|
|
const Variable *otherVar = otherVarToken->variable();
|
|
if (otherVar && Token::Match(otherVar->nameToken(), "%var% :") &&
|
|
otherVar->nameToken()->next()->astParent() &&
|
|
Token::simpleMatch(otherVar->nameToken()->next()->astParent()->previous(), "for ("))
|
|
continue;
|
|
}
|
|
|
|
bool forHead = false; // Don't check variables declared in header of a for loop
|
|
for (const Token* tok = var->typeStartToken(); tok; tok = tok->previous()) {
|
|
if (tok->str() == "(") {
|
|
forHead = true;
|
|
break;
|
|
} else if (Token::Match(tok, "[;{}]"))
|
|
break;
|
|
}
|
|
if (forHead)
|
|
continue;
|
|
|
|
const Token* tok = var->nameToken()->next();
|
|
if (Token::Match(tok, "; %varid% = %any% ;", var->declarationId())) {
|
|
tok = tok->tokAt(3);
|
|
if (!tok->isNumber() && tok->tokType() != Token::eString && tok->tokType() != Token::eChar && !tok->isBoolean())
|
|
continue;
|
|
}
|
|
// bailout if initialized with function call that has possible side effects
|
|
if (Token::Match(tok, "[(=]") && Token::simpleMatch(tok->astOperand2(), "("))
|
|
continue;
|
|
bool reduce = true;
|
|
bool used = false; // Don't warn about unused variables
|
|
for (; tok && tok != var->scope()->bodyEnd; tok = tok->next()) {
|
|
if (tok->str() == "{" && tok->scope() != tok->previous()->scope() && !tok->isExpandedMacro() && tok->scope()->type != Scope::eLambda) {
|
|
if (used) {
|
|
bool used2 = false;
|
|
if (!checkInnerScope(tok, var, used2) || used2) {
|
|
reduce = false;
|
|
break;
|
|
}
|
|
} else if (!checkInnerScope(tok, var, used)) {
|
|
reduce = false;
|
|
break;
|
|
}
|
|
|
|
tok = tok->link();
|
|
|
|
// parse else if blocks..
|
|
} else if (Token::simpleMatch(tok, "else { if (") && Token::simpleMatch(tok->linkAt(3), ") {")) {
|
|
const Token *endif = tok->linkAt(3)->linkAt(1);
|
|
bool elseif = false;
|
|
if (Token::simpleMatch(endif, "} }"))
|
|
elseif = true;
|
|
else if (Token::simpleMatch(endif, "} else {") && Token::simpleMatch(endif->linkAt(2),"} }"))
|
|
elseif = true;
|
|
if (elseif && Token::findmatch(tok->next(), "%varid%", tok->linkAt(1), var->declarationId())) {
|
|
reduce = false;
|
|
break;
|
|
}
|
|
} else if (tok->varId() == var->declarationId() || tok->str() == "goto") {
|
|
reduce = false;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (reduce && used)
|
|
variableScopeError(var->nameToken(), var->name());
|
|
}
|
|
}
|
|
|
|
bool CheckOther::checkInnerScope(const Token *tok, const Variable* var, bool& used)
|
|
{
|
|
const Scope* scope = tok->next()->scope();
|
|
bool loopVariable = scope->isLoopScope();
|
|
bool noContinue = true;
|
|
const Token* forHeadEnd = nullptr;
|
|
const Token* end = tok->link();
|
|
if (scope->type == Scope::eUnconditional && (tok->strAt(-1) == ")" || tok->previous()->isName())) // Might be an unknown macro like BOOST_FOREACH
|
|
loopVariable = true;
|
|
|
|
if (scope->type == Scope::eDo) {
|
|
end = end->linkAt(2);
|
|
} else if (loopVariable && tok->strAt(-1) == ")") {
|
|
tok = tok->linkAt(-1); // Jump to opening ( of for/while statement
|
|
} else if (scope->type == Scope::eSwitch) {
|
|
for (const Scope* innerScope : scope->nestedList) {
|
|
if (used) {
|
|
bool used2 = false;
|
|
if (!checkInnerScope(innerScope->bodyStart, var, used2) || used2) {
|
|
return false;
|
|
}
|
|
} else if (!checkInnerScope(innerScope->bodyStart, var, used)) {
|
|
return false;
|
|
}
|
|
}
|
|
}
|
|
|
|
bool bFirstAssignment=false;
|
|
for (; tok && tok != end; tok = tok->next()) {
|
|
if (tok->str() == "goto")
|
|
return false;
|
|
if (tok->str() == "continue")
|
|
noContinue = false;
|
|
|
|
if (Token::simpleMatch(tok, "for ("))
|
|
forHeadEnd = tok->linkAt(1);
|
|
if (tok == forHeadEnd)
|
|
forHeadEnd = nullptr;
|
|
|
|
if (loopVariable && noContinue && tok->scope() == scope && !forHeadEnd && scope->type != Scope::eSwitch && Token::Match(tok, "%varid% =", var->declarationId())) { // Assigned in outer scope.
|
|
loopVariable = false;
|
|
int indent = 0;
|
|
for (const Token* tok2 = tok->tokAt(2); tok2; tok2 = tok2->next()) { // Ensure that variable isn't used on right side of =, too
|
|
if (tok2->str() == "(")
|
|
indent++;
|
|
else if (tok2->str() == ")") {
|
|
if (indent == 0)
|
|
break;
|
|
indent--;
|
|
} else if (tok2->str() == ";")
|
|
break;
|
|
else if (tok2->varId() == var->declarationId()) {
|
|
loopVariable = true;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (loopVariable && Token::Match(tok, "%varid% !!=", var->declarationId())) // Variable used in loop
|
|
return false;
|
|
|
|
if (Token::Match(tok, "& %varid%", var->declarationId())) // Taking address of variable
|
|
return false;
|
|
|
|
if (Token::Match(tok, "%varid% =", var->declarationId()))
|
|
bFirstAssignment = true;
|
|
|
|
if (!bFirstAssignment && Token::Match(tok, "* %varid%", var->declarationId())) // dereferencing means access to previous content
|
|
return false;
|
|
|
|
if (Token::Match(tok, "= %varid%", var->declarationId()) && (var->isArray() || var->isPointer())) // Create a copy of array/pointer. Bailout, because the memory it points to might be necessary in outer scope
|
|
return false;
|
|
|
|
if (tok->varId() == var->declarationId()) {
|
|
used = true;
|
|
if (scope->type == Scope::eSwitch && scope == tok->scope())
|
|
return false; // Used in outer switch scope - unsafe or impossible to reduce scope
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
void CheckOther::variableScopeError(const Token *tok, const std::string &varname)
|
|
{
|
|
reportError(tok,
|
|
Severity::style,
|
|
"variableScope",
|
|
"$symbol:" + varname + "\n"
|
|
"The scope of the variable '$symbol' can be reduced.\n"
|
|
"The scope of the variable '$symbol' can be reduced. Warning: Be careful "
|
|
"when fixing this message, especially when there are inner loops. Here is an "
|
|
"example where cppcheck will write that the scope for 'i' can be reduced:\n"
|
|
"void f(int x)\n"
|
|
"{\n"
|
|
" int i = 0;\n"
|
|
" if (x) {\n"
|
|
" // it's safe to move 'int i = 0;' here\n"
|
|
" for (int n = 0; n < 10; ++n) {\n"
|
|
" // it is possible but not safe to move 'int i = 0;' here\n"
|
|
" do_something(&i);\n"
|
|
" }\n"
|
|
" }\n"
|
|
"}\n"
|
|
"When you see this message it is always safe to reduce the variable scope 1 level.", CWE398, Certainty::normal);
|
|
}
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Comma in return statement: return a+1, b++;. (experimental)
|
|
//---------------------------------------------------------------------------
|
|
void CheckOther::checkCommaSeparatedReturn()
|
|
{
|
|
// This is experimental for now. See #5076
|
|
if (!mSettings->certainty.isEnabled(Certainty::experimental))
|
|
return;
|
|
|
|
if (!mSettings->severity.isEnabled(Severity::style))
|
|
return;
|
|
|
|
for (const Token *tok = mTokenizer->tokens(); tok; tok = tok->next()) {
|
|
if (tok->str() == "return") {
|
|
tok = tok->next();
|
|
while (tok && tok->str() != ";") {
|
|
if (tok->link() && Token::Match(tok, "[([{<]"))
|
|
tok = tok->link();
|
|
|
|
if (!tok->isExpandedMacro() && tok->str() == "," && tok->linenr() != tok->next()->linenr())
|
|
commaSeparatedReturnError(tok);
|
|
|
|
tok = tok->next();
|
|
}
|
|
// bailout: missing semicolon (invalid code / bad tokenizer)
|
|
if (!tok)
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckOther::commaSeparatedReturnError(const Token *tok)
|
|
{
|
|
reportError(tok,
|
|
Severity::style,
|
|
"commaSeparatedReturn",
|
|
"Comma is used in return statement. The comma can easily be misread as a ';'.\n"
|
|
"Comma is used in return statement. When comma is used in a return statement it can "
|
|
"easily be misread as a semicolon. For example in the code below the value "
|
|
"of 'b' is returned if the condition is true, but it is easy to think that 'a+1' is "
|
|
"returned:\n"
|
|
" if (x)\n"
|
|
" return a + 1,\n"
|
|
" b++;\n"
|
|
"However it can be useful to use comma in macros. Cppcheck does not warn when such a "
|
|
"macro is then used in a return statement, it is less likely such code is misunderstood.", CWE398, Certainty::normal);
|
|
}
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Check for function parameters that should be passed by const reference
|
|
//---------------------------------------------------------------------------
|
|
static int estimateSize(const Type* type, const Settings* settings, const SymbolDatabase* symbolDatabase, int recursionDepth = 0)
|
|
{
|
|
if (recursionDepth > 20)
|
|
return 0;
|
|
|
|
int cumulatedSize = 0;
|
|
for (const Variable&var : type->classScope->varlist) {
|
|
int size = 0;
|
|
if (var.isStatic())
|
|
continue;
|
|
if (var.isPointer() || var.isReference())
|
|
size = settings->sizeof_pointer;
|
|
else if (var.type() && var.type()->classScope)
|
|
size = estimateSize(var.type(), settings, symbolDatabase, recursionDepth+1);
|
|
else if (var.valueType()->type == ValueType::Type::CONTAINER)
|
|
size = 3 * settings->sizeof_pointer; // Just guess
|
|
else
|
|
size = symbolDatabase->sizeOfType(var.typeStartToken());
|
|
|
|
if (var.isArray())
|
|
cumulatedSize += size * var.dimension(0);
|
|
else
|
|
cumulatedSize += size;
|
|
}
|
|
for (const Type::BaseInfo &baseInfo : type->derivedFrom) {
|
|
if (baseInfo.type && baseInfo.type->classScope)
|
|
cumulatedSize += estimateSize(baseInfo.type, settings, symbolDatabase, recursionDepth+1);
|
|
}
|
|
return cumulatedSize;
|
|
}
|
|
|
|
static bool canBeConst(const Variable *var, const Settings* settings)
|
|
{
|
|
{
|
|
// check initializer list. If variable is moved from it can't be const.
|
|
const Function* func_scope = var->scope()->function;
|
|
if (func_scope->type == Function::Type::eConstructor) {
|
|
//could be initialized in initializer list
|
|
if (func_scope->arg->link()->next()->str() == ":") {
|
|
for (const Token* tok2 = func_scope->arg->link()->next()->next(); tok2 != var->scope()->bodyStart; tok2 = tok2->next()) {
|
|
if (tok2->varId() != var->declarationId())
|
|
continue;
|
|
const Token* parent = tok2->astParent();
|
|
if (parent && Token::simpleMatch(parent->previous(), "move ("))
|
|
return false;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
for (const Token* tok2 = var->scope()->bodyStart; tok2 != var->scope()->bodyEnd; tok2 = tok2->next()) {
|
|
if (tok2->varId() != var->declarationId())
|
|
continue;
|
|
|
|
const Token* parent = tok2->astParent();
|
|
if (!parent)
|
|
continue;
|
|
if (parent->str() == "<<" || isLikelyStreamRead(true, parent)) {
|
|
if (parent->str() == "<<" && parent->astOperand1() == tok2)
|
|
return false;
|
|
if (parent->str() == ">>" && parent->astOperand2() == tok2)
|
|
return false;
|
|
} else if (parent->str() == "," || parent->str() == "(") { // function argument
|
|
const Token* tok3 = tok2->previous();
|
|
int argNr = 0;
|
|
while (tok3 && tok3->str() != "(") {
|
|
if (tok3->link() && Token::Match(tok3, ")|]|}|>"))
|
|
tok3 = tok3->link();
|
|
else if (tok3->link())
|
|
break;
|
|
else if (tok3->str() == ";")
|
|
break;
|
|
else if (tok3->str() == ",")
|
|
argNr++;
|
|
tok3 = tok3->previous();
|
|
}
|
|
if (!tok3 || tok3->str() != "(")
|
|
return false;
|
|
const Token* functionTok = tok3->astOperand1();
|
|
if (!functionTok)
|
|
return false;
|
|
const Function* tokFunction = functionTok->function();
|
|
if (!tokFunction && functionTok->str() == "." && (functionTok = functionTok->astOperand2()))
|
|
tokFunction = functionTok->function();
|
|
if (tokFunction) {
|
|
const Variable* argVar = tokFunction->getArgumentVar(argNr);
|
|
if (!argVar || (!argVar->isConst() && argVar->isReference()))
|
|
return false;
|
|
}
|
|
else if (!settings->library.isFunctionConst(functionTok))
|
|
return false;
|
|
} else if (parent->isUnaryOp("&")) {
|
|
// TODO: check how pointer is used
|
|
return false;
|
|
} else if (parent->isConstOp() ||
|
|
(parent->astOperand2() && settings->library.isFunctionConst(parent->astOperand2())))
|
|
continue;
|
|
else if (parent->isAssignmentOp()) {
|
|
if (parent->astOperand1() == tok2)
|
|
return false;
|
|
const Variable* assignedVar = parent->astOperand1() ? parent->astOperand1()->variable() : nullptr;
|
|
if (assignedVar &&
|
|
!assignedVar->isConst() &&
|
|
assignedVar->isReference() &&
|
|
assignedVar->nameToken() == parent->astOperand1())
|
|
return false;
|
|
} else if (Token::Match(tok2, "%var% . %name% (")) {
|
|
const Function* func = tok2->tokAt(2)->function();
|
|
if (func && (func->isConst() || func->isStatic()))
|
|
continue;
|
|
else
|
|
return false;
|
|
} else
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
void CheckOther::checkPassByReference()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::performance) || mTokenizer->isC())
|
|
return;
|
|
|
|
const SymbolDatabase * const symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
|
|
for (const Variable* var : symbolDatabase->variableList()) {
|
|
if (!var || !var->isArgument() || !var->isClass() || var->isPointer() || var->isArray() || var->isReference() || var->isEnumType())
|
|
continue;
|
|
|
|
if (var->scope() && var->scope()->function->arg->link()->strAt(-1) == "...")
|
|
continue; // references could not be used as va_start parameters (#5824)
|
|
|
|
if ((var->declEndToken() && var->declEndToken()->isExternC()) ||
|
|
(var->scope() && var->scope()->function && var->scope()->function->tokenDef && var->scope()->function->tokenDef->isExternC()))
|
|
continue; // references cannot be used in functions in extern "C" blocks
|
|
|
|
bool inconclusive = false;
|
|
|
|
if (var->valueType() && var->valueType()->type == ValueType::Type::CONTAINER) {} else if (var->type() && !var->type()->isEnumType()) { // Check if type is a struct or class.
|
|
// Ensure that it is a large object.
|
|
if (!var->type()->classScope)
|
|
inconclusive = true;
|
|
else if (estimateSize(var->type(), mSettings, symbolDatabase) <= 2 * mSettings->sizeof_pointer)
|
|
continue;
|
|
} else
|
|
continue;
|
|
|
|
if (inconclusive && !mSettings->certainty.isEnabled(Certainty::inconclusive))
|
|
continue;
|
|
|
|
const bool isConst = var->isConst();
|
|
if (isConst) {
|
|
passedByValueError(var->nameToken(), var->name(), inconclusive);
|
|
continue;
|
|
}
|
|
|
|
// Check if variable could be const
|
|
if (!var->scope() || var->scope()->function->hasVirtualSpecifier())
|
|
continue;
|
|
|
|
if (canBeConst(var, mSettings)) {
|
|
passedByValueError(var->nameToken(), var->name(), inconclusive);
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckOther::passedByValueError(const Token *tok, const std::string &parname, bool inconclusive)
|
|
{
|
|
reportError(tok, Severity::performance, "passedByValue",
|
|
"$symbol:" + parname + "\n"
|
|
"Function parameter '$symbol' should be passed by const reference.\n"
|
|
"Parameter '$symbol' is passed by value. It could be passed "
|
|
"as a const reference which is usually faster and recommended in C++.", CWE398, inconclusive ? Certainty::inconclusive : Certainty::normal);
|
|
}
|
|
|
|
static bool isUnusedVariable(const Variable *var)
|
|
{
|
|
if (!var)
|
|
return false;
|
|
if (!var->scope())
|
|
return false;
|
|
const Token *start = var->declEndToken();
|
|
if (!start)
|
|
return false;
|
|
if (Token::Match(start, "; %varid% =", var->declarationId()))
|
|
start = start->tokAt(2);
|
|
return !Token::findmatch(start->next(), "%varid%", var->scope()->bodyEnd, var->declarationId());
|
|
}
|
|
|
|
static bool isVariableMutableInInitializer(const Token* start, const Token * end, nonneg int varid)
|
|
{
|
|
if (!start)
|
|
return false;
|
|
if (!end)
|
|
return false;
|
|
for (const Token *tok = start; tok != end; tok = tok->next()) {
|
|
if (tok->varId() != varid)
|
|
continue;
|
|
if (tok->astParent()) {
|
|
const Token * memberTok = tok->astParent()->previous();
|
|
if (Token::Match(memberTok, "%var% (") && memberTok->variable()) {
|
|
const Variable * memberVar = memberTok->variable();
|
|
if (memberVar->isClass())
|
|
//TODO: check if the called constructor could live with a const variable
|
|
// pending that, assume the worst (that it can't)
|
|
return true;
|
|
if (!memberVar->isReference())
|
|
continue;
|
|
if (memberVar->isConst())
|
|
continue;
|
|
}
|
|
return true;
|
|
} else {
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
void CheckOther::checkConstVariable()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::style) || mTokenizer->isC())
|
|
return;
|
|
|
|
const SymbolDatabase *const symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
|
|
for (const Variable *var : symbolDatabase->variableList()) {
|
|
if (!var)
|
|
continue;
|
|
if (!var->isReference())
|
|
continue;
|
|
if (var->isRValueReference())
|
|
continue;
|
|
if (var->isPointer())
|
|
continue;
|
|
if (var->isConst())
|
|
continue;
|
|
if (!var->scope())
|
|
continue;
|
|
const Scope *scope = var->scope();
|
|
if (!scope->function)
|
|
continue;
|
|
const Function *function = scope->function;
|
|
if (var->isArgument()) {
|
|
if (function->isImplicitlyVirtual() || function->templateDef)
|
|
continue;
|
|
if (isUnusedVariable(var))
|
|
continue;
|
|
if (function->isConstructor() && isVariableMutableInInitializer(function->constructorMemberInitialization(), scope->bodyStart, var->declarationId()))
|
|
continue;
|
|
}
|
|
if (var->isGlobal())
|
|
continue;
|
|
if (var->isStatic())
|
|
continue;
|
|
if (var->isArray())
|
|
continue;
|
|
if (var->isEnumType())
|
|
continue;
|
|
if (var->isVolatile())
|
|
continue;
|
|
if (isAliased(var))
|
|
continue;
|
|
if (isVariableChanged(var, mSettings, mTokenizer->isCPP()))
|
|
continue;
|
|
if (Function::returnsReference(function) && !Function::returnsConst(function)) {
|
|
std::vector<const Token*> returns = Function::findReturns(function);
|
|
if (std::any_of(returns.begin(), returns.end(), [&](const Token* retTok) {
|
|
if (retTok->varId() == var->declarationId())
|
|
return true;
|
|
while (retTok && retTok->isCast())
|
|
retTok = retTok->astOperand2();
|
|
while (Token::simpleMatch(retTok, "."))
|
|
retTok = retTok->astOperand2();
|
|
return hasLifetimeToken(getParentLifetime(retTok), var->nameToken());
|
|
}))
|
|
continue;
|
|
}
|
|
// Skip if address is taken
|
|
if (Token::findmatch(var->nameToken(), "& %varid%", scope->bodyEnd, var->declarationId()))
|
|
continue;
|
|
// Skip if another non-const variable is initialized with this variable
|
|
{
|
|
//Is it the right side of an initialization of a non-const reference
|
|
bool usedInAssignment = false;
|
|
for (const Token* tok = var->nameToken(); tok != scope->bodyEnd && tok != nullptr; tok = tok->next()) {
|
|
if (Token::Match(tok, "& %var% = %varid%", var->declarationId())) {
|
|
const Variable* refvar = tok->next()->variable();
|
|
if (refvar && !refvar->isConst() && refvar->nameToken() == tok->next()) {
|
|
usedInAssignment = true;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
if (usedInAssignment)
|
|
continue;
|
|
}
|
|
// Skip if we ever cast this variable to a pointer/reference to a non-const type
|
|
{
|
|
bool castToNonConst = false;
|
|
for (const Token* tok = var->nameToken(); tok != scope->bodyEnd && tok != nullptr; tok = tok->next()) {
|
|
if (tok->isCast()) {
|
|
if (!tok->valueType()) {
|
|
castToNonConst = true; // safe guess
|
|
break;
|
|
}
|
|
bool isConst = 0 != (tok->valueType()->constness & (1 << tok->valueType()->pointer));
|
|
if (!isConst) {
|
|
castToNonConst = true;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
if (castToNonConst)
|
|
continue;
|
|
}
|
|
// Do not warn if struct data is changed
|
|
{
|
|
bool changeStructData = false;
|
|
for (const Token* tok = var->nameToken(); tok != scope->bodyEnd && tok != nullptr; tok = tok->next()) {
|
|
if (tok->variable() == var && Token::Match(tok, "%var% .")) {
|
|
const Token *parent = tok;
|
|
while (Token::simpleMatch(parent->astParent(), ".") && parent == parent->astParent()->astOperand1())
|
|
parent = parent->astParent();
|
|
if (parent->valueType() &&
|
|
parent->valueType()->pointer > 0 &&
|
|
parent->valueType()->constness == 0 &&
|
|
isVariableChanged(parent, 1, mSettings, mTokenizer->isCPP())) {
|
|
changeStructData = true;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
if (changeStructData)
|
|
continue;
|
|
}
|
|
// Calling non-const method using non-const reference
|
|
if (var->isReference()) {
|
|
bool callNonConstMethod = false;
|
|
for (const Token* tok = var->nameToken(); tok != scope->bodyEnd && tok != nullptr; tok = tok->next()) {
|
|
if (tok->variable() == var && Token::Match(tok, "%var% . * ( & %name% ::")) {
|
|
const Token *ftok = tok->linkAt(3)->previous();
|
|
if (!ftok->function() || !ftok->function()->isConst())
|
|
callNonConstMethod = true;
|
|
break;
|
|
}
|
|
}
|
|
if (callNonConstMethod)
|
|
continue;
|
|
}
|
|
|
|
constVariableError(var, function);
|
|
}
|
|
}
|
|
|
|
void CheckOther::checkConstPointer()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::style))
|
|
return;
|
|
|
|
std::set<const Variable *> pointers;
|
|
std::set<const Variable *> nonConstPointers;
|
|
for (const Token *tok = mTokenizer->tokens(); tok; tok = tok->next()) {
|
|
if (!tok->variable())
|
|
continue;
|
|
if (!tok->variable()->isLocal() && !tok->variable()->isArgument())
|
|
continue;
|
|
if (tok == tok->variable()->nameToken())
|
|
continue;
|
|
if (!tok->valueType())
|
|
continue;
|
|
if (tok->valueType()->pointer == 0 || tok->valueType()->constness > 0)
|
|
continue;
|
|
if (nonConstPointers.find(tok->variable()) != nonConstPointers.end())
|
|
continue;
|
|
pointers.insert(tok->variable());
|
|
const Token *parent = tok->astParent();
|
|
bool deref = false;
|
|
if (parent && parent->isUnaryOp("*"))
|
|
deref = true;
|
|
else if (Token::simpleMatch(parent, "[") && parent->astOperand1() == tok)
|
|
deref = true;
|
|
if (deref) {
|
|
if (Token::Match(parent->astParent(), "%cop%") && !parent->astParent()->isUnaryOp("&") && !parent->astParent()->isUnaryOp("*"))
|
|
continue;
|
|
if (Token::simpleMatch(parent->astParent(), "return"))
|
|
continue;
|
|
else if (Token::Match(parent->astParent(), "%assign%") && parent == parent->astParent()->astOperand2()) {
|
|
bool takingRef = false;
|
|
const Token *lhs = parent->astParent()->astOperand1();
|
|
if (lhs && lhs->variable() && lhs->variable()->isReference() && lhs->variable()->nameToken() == lhs)
|
|
takingRef = true;
|
|
if (!takingRef)
|
|
continue;
|
|
} else if (Token::simpleMatch(parent->astParent(), "[") && parent->astParent()->astOperand2() == parent)
|
|
continue;
|
|
} else {
|
|
if (Token::Match(parent, "%oror%|%comp%|&&|?|!|-"))
|
|
continue;
|
|
else if (Token::simpleMatch(parent, "(") && Token::Match(parent->astOperand1(), "if|while"))
|
|
continue;
|
|
}
|
|
nonConstPointers.insert(tok->variable());
|
|
}
|
|
for (const Variable *p: pointers) {
|
|
if (p->isArgument()) {
|
|
if (!p->scope() || !p->scope()->function || p->scope()->function->isImplicitlyVirtual(true) || p->scope()->function->hasVirtualSpecifier())
|
|
continue;
|
|
}
|
|
if (nonConstPointers.find(p) == nonConstPointers.end()) {
|
|
const Token *start = (p->isArgument()) ? p->scope()->bodyStart : p->nameToken()->next();
|
|
const int indirect = p->isArray() ? p->dimensions().size() : 1;
|
|
if (isVariableChanged(start, p->scope()->bodyEnd, indirect, p->declarationId(), false, mSettings, mTokenizer->isCPP()))
|
|
continue;
|
|
constVariableError(p, nullptr);
|
|
}
|
|
}
|
|
}
|
|
void CheckOther::constVariableError(const Variable *var, const Function *function)
|
|
{
|
|
const std::string vartype((var && var->isArgument()) ? "Parameter" : "Variable");
|
|
const std::string varname(var ? var->name() : std::string("x"));
|
|
|
|
ErrorPath errorPath;
|
|
std::string id = "const" + vartype;
|
|
std::string message = "$symbol:" + varname + "\n" + vartype + " '$symbol' can be declared with const";
|
|
errorPath.push_back(ErrorPathItem(var ? var->nameToken() : nullptr, message));
|
|
if (var && var->isArgument() && function && function->functionPointerUsage) {
|
|
errorPath.push_front(ErrorPathItem(function->functionPointerUsage, "You might need to cast the function pointer here"));
|
|
id += "Callback";
|
|
message += ". However it seems that '" + function->name() + "' is a callback function, if '$symbol' is declared with const you might also need to cast function pointer(s).";
|
|
}
|
|
|
|
reportError(errorPath, Severity::style, id.c_str(), message, CWE398, Certainty::normal);
|
|
}
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Check usage of char variables..
|
|
//---------------------------------------------------------------------------
|
|
|
|
void CheckOther::checkCharVariable()
|
|
{
|
|
const bool warning = mSettings->severity.isEnabled(Severity::warning);
|
|
const bool portability = mSettings->severity.isEnabled(Severity::portability);
|
|
if (!warning && !portability)
|
|
return;
|
|
|
|
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::Match(tok, "%var% [")) {
|
|
if (!tok->variable())
|
|
continue;
|
|
if (!tok->variable()->isArray() && !tok->variable()->isPointer())
|
|
continue;
|
|
const Token *index = tok->next()->astOperand2();
|
|
if (warning && tok->variable()->isArray() && astIsSignedChar(index) && index->getValueGE(0x80, mSettings))
|
|
signedCharArrayIndexError(tok);
|
|
if (portability && astIsUnknownSignChar(index) && index->getValueGE(0x80, mSettings))
|
|
unknownSignCharArrayIndexError(tok);
|
|
} else if (warning && Token::Match(tok, "[&|^]") && tok->isBinaryOp()) {
|
|
bool warn = false;
|
|
if (astIsSignedChar(tok->astOperand1())) {
|
|
const ValueFlow::Value *v1 = tok->astOperand1()->getValueLE(-1, mSettings);
|
|
const ValueFlow::Value *v2 = tok->astOperand2()->getMaxValue(false);
|
|
if (!v1)
|
|
v1 = tok->astOperand1()->getValueGE(0x80, mSettings);
|
|
if (v1 && !(tok->str() == "&" && v2 && v2->isKnown() && v2->intvalue >= 0 && v2->intvalue < 0x100))
|
|
warn = true;
|
|
} else if (astIsSignedChar(tok->astOperand2())) {
|
|
const ValueFlow::Value *v1 = tok->astOperand2()->getValueLE(-1, mSettings);
|
|
const ValueFlow::Value *v2 = tok->astOperand1()->getMaxValue(false);
|
|
if (!v1)
|
|
v1 = tok->astOperand2()->getValueGE(0x80, mSettings);
|
|
if (v1 && !(tok->str() == "&" && v2 && v2->isKnown() && v2->intvalue >= 0 && v2->intvalue < 0x100))
|
|
warn = true;
|
|
}
|
|
|
|
// is the result stored in a short|int|long?
|
|
if (warn && Token::simpleMatch(tok->astParent(), "=")) {
|
|
const Token *lhs = tok->astParent()->astOperand1();
|
|
if (lhs && lhs->valueType() && lhs->valueType()->type >= ValueType::Type::SHORT)
|
|
charBitOpError(tok); // This is an error..
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckOther::signedCharArrayIndexError(const Token *tok)
|
|
{
|
|
reportError(tok,
|
|
Severity::warning,
|
|
"signedCharArrayIndex",
|
|
"Signed 'char' type used as array index.\n"
|
|
"Signed 'char' type used as array index. If the value "
|
|
"can be greater than 127 there will be a buffer underflow "
|
|
"because of sign extension.", CWE128, Certainty::normal);
|
|
}
|
|
|
|
void CheckOther::unknownSignCharArrayIndexError(const Token *tok)
|
|
{
|
|
reportError(tok,
|
|
Severity::portability,
|
|
"unknownSignCharArrayIndex",
|
|
"'char' type used as array index.\n"
|
|
"'char' type used as array index. Values greater than 127 will be "
|
|
"treated depending on whether 'char' is signed or unsigned on target platform.", CWE758, Certainty::normal);
|
|
}
|
|
|
|
void CheckOther::charBitOpError(const Token *tok)
|
|
{
|
|
reportError(tok,
|
|
Severity::warning,
|
|
"charBitOp",
|
|
"When using 'char' variables in bit operations, sign extension can generate unexpected results.\n"
|
|
"When using 'char' variables in bit operations, sign extension can generate unexpected results. For example:\n"
|
|
" char c = 0x80;\n"
|
|
" int i = 0 | c;\n"
|
|
" if (i & 0x8000)\n"
|
|
" printf(\"not expected\");\n"
|
|
"The \"not expected\" will be printed on the screen.", CWE398, Certainty::normal);
|
|
}
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Incomplete statement..
|
|
//---------------------------------------------------------------------------
|
|
|
|
static bool isType(const Token * tok, bool unknown)
|
|
{
|
|
if (Token::Match(tok, "%type%"))
|
|
return true;
|
|
if (Token::simpleMatch(tok, "::"))
|
|
return isType(tok->astOperand2(), unknown);
|
|
if (Token::simpleMatch(tok, "<") && tok->link())
|
|
return true;
|
|
if (unknown && Token::Match(tok, "%name% !!("))
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
static bool isVarDeclOp(const Token* tok)
|
|
{
|
|
if (!tok)
|
|
return false;
|
|
const Token * vartok = tok->astOperand2();
|
|
if (vartok && vartok->variable() && vartok->variable()->nameToken() == vartok)
|
|
return true;
|
|
const Token * typetok = tok->astOperand1();
|
|
return isType(typetok, Token::Match(vartok, "%var%"));
|
|
}
|
|
|
|
static bool isConstStatement(const Token *tok)
|
|
{
|
|
if (!tok)
|
|
return false;
|
|
if (tok->isExpandedMacro())
|
|
return false;
|
|
if (Token::Match(tok, "%bool%|%num%|%str%|%char%|nullptr|NULL"))
|
|
return true;
|
|
if (Token::Match(tok, "%var%"))
|
|
return true;
|
|
if (Token::Match(tok, "*|&|&&") &&
|
|
(Token::Match(tok->previous(), "::|.|const|volatile|restrict") || isVarDeclOp(tok)))
|
|
return false;
|
|
if (Token::Match(tok, "<<|>>") && !astIsIntegral(tok, false))
|
|
return false;
|
|
if (Token::Match(tok, "!|~|%cop%") && (tok->astOperand1() || tok->astOperand2()))
|
|
return true;
|
|
if (Token::simpleMatch(tok->previous(), "sizeof ("))
|
|
return true;
|
|
if (isCPPCast(tok))
|
|
return isConstStatement(tok->astOperand2());
|
|
if (Token::Match(tok, "( %type%"))
|
|
return isConstStatement(tok->astOperand1());
|
|
if (Token::simpleMatch(tok, ","))
|
|
return isConstStatement(tok->astOperand2());
|
|
return false;
|
|
}
|
|
|
|
static bool isVoidStmt(const Token *tok)
|
|
{
|
|
if (Token::simpleMatch(tok, "( void"))
|
|
return true;
|
|
const Token *tok2 = tok;
|
|
while (tok2->astOperand1())
|
|
tok2 = tok2->astOperand1();
|
|
if (Token::simpleMatch(tok2->previous(), ")") && Token::simpleMatch(tok2->previous()->link(), "( void"))
|
|
return true;
|
|
if (Token::simpleMatch(tok2, "( void"))
|
|
return true;
|
|
return Token::Match(tok2->previous(), "delete|throw|return");
|
|
}
|
|
|
|
static bool isConstTop(const Token *tok)
|
|
{
|
|
if (!tok)
|
|
return false;
|
|
if (!tok->astParent())
|
|
return true;
|
|
if (Token::simpleMatch(tok->astParent(), ";") &&
|
|
Token::Match(tok->astTop()->previous(), "for|if (") && Token::simpleMatch(tok->astTop()->astOperand2(), ";")) {
|
|
if (Token::simpleMatch(tok->astParent()->astParent(), ";"))
|
|
return tok->astParent()->astOperand2() == tok;
|
|
else
|
|
return tok->astParent()->astOperand1() == tok;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
void CheckOther::checkIncompleteStatement()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::warning))
|
|
return;
|
|
|
|
for (const Token *tok = mTokenizer->tokens(); tok; tok = tok->next()) {
|
|
const Scope *scope = tok->scope();
|
|
if (scope && !scope->isExecutable())
|
|
continue;
|
|
if (!isConstTop(tok))
|
|
continue;
|
|
if (tok->str() == "," && Token::simpleMatch(tok->astTop()->previous(), "for ("))
|
|
continue;
|
|
|
|
// Do not warn for statement when both lhs and rhs has side effects:
|
|
// dostuff() || x=213;
|
|
if (Token::Match(tok, "%oror%|&&")) {
|
|
bool warn = false;
|
|
visitAstNodes(tok, [&warn](const Token *child) {
|
|
if (Token::Match(child, "%oror%|&&"))
|
|
return ChildrenToVisit::op1_and_op2;
|
|
if (child->isAssignmentOp())
|
|
return ChildrenToVisit::none;
|
|
if (child->tokType() == Token::Type::eIncDecOp)
|
|
return ChildrenToVisit::none;
|
|
if (Token::Match(child->previous(), "%name% ("))
|
|
return ChildrenToVisit::none;
|
|
warn = true;
|
|
return ChildrenToVisit::done;
|
|
});
|
|
if (!warn)
|
|
continue;
|
|
}
|
|
|
|
const Token *rtok = nextAfterAstRightmostLeaf(tok);
|
|
if (!Token::simpleMatch(tok->astParent(), ";") && !Token::simpleMatch(rtok, ";") &&
|
|
!Token::Match(tok->previous(), ";|}|{ %any% ;"))
|
|
continue;
|
|
// Skip statement expressions
|
|
if (Token::simpleMatch(rtok, "; } )"))
|
|
continue;
|
|
if (!isConstStatement(tok))
|
|
continue;
|
|
if (isVoidStmt(tok))
|
|
continue;
|
|
if (mTokenizer->isCPP() && tok->str() == "&" && !(tok->astOperand1()->valueType() && tok->astOperand1()->valueType()->isIntegral()))
|
|
// Possible archive
|
|
continue;
|
|
bool inconclusive = Token::Match(tok, "%cop%");
|
|
if (mSettings->certainty.isEnabled(Certainty::inconclusive) || !inconclusive)
|
|
constStatementError(tok, tok->isNumber() ? "numeric" : "string", inconclusive);
|
|
}
|
|
}
|
|
|
|
void CheckOther::constStatementError(const Token *tok, const std::string &type, bool inconclusive)
|
|
{
|
|
const Token *valueTok = tok;
|
|
while (valueTok && valueTok->isCast())
|
|
valueTok = valueTok->astOperand2() ? valueTok->astOperand2() : valueTok->astOperand1();
|
|
|
|
std::string msg;
|
|
if (Token::simpleMatch(tok, "=="))
|
|
msg = "Found suspicious equality comparison. Did you intend to assign a value instead?";
|
|
else if (Token::Match(tok, ",|!|~|%cop%"))
|
|
msg = "Found suspicious operator '" + tok->str() + "'";
|
|
else if (Token::Match(tok, "%var%"))
|
|
msg = "Unused variable value '" + tok->str() + "'";
|
|
else if (Token::Match(valueTok, "%str%|%num%"))
|
|
msg = "Redundant code: Found a statement that begins with " + std::string(valueTok->isNumber() ? "numeric" : "string") + " constant.";
|
|
else if (!tok)
|
|
msg = "Redundant code: Found a statement that begins with " + type + " constant.";
|
|
else
|
|
return; // Strange!
|
|
reportError(tok, Severity::warning, "constStatement", msg, CWE398, inconclusive ? Certainty::inconclusive : Certainty::normal);
|
|
}
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Detect division by zero.
|
|
//---------------------------------------------------------------------------
|
|
void CheckOther::checkZeroDivision()
|
|
{
|
|
for (const Token *tok = mTokenizer->tokens(); tok; tok = tok->next()) {
|
|
if (!tok->astOperand2() || !tok->astOperand1())
|
|
continue;
|
|
if (tok->str() != "%" && tok->str() != "/" && tok->str() != "%=" && tok->str() != "/=")
|
|
continue;
|
|
if (!tok->valueType() || !tok->valueType()->isIntegral())
|
|
continue;
|
|
|
|
// Value flow..
|
|
const ValueFlow::Value *value = tok->astOperand2()->getValue(0LL);
|
|
if (value && mSettings->isEnabled(value, false))
|
|
zerodivError(tok, value);
|
|
}
|
|
}
|
|
|
|
void CheckOther::zerodivError(const Token *tok, const ValueFlow::Value *value)
|
|
{
|
|
if (!tok && !value) {
|
|
reportError(tok, Severity::error, "zerodiv", "Division by zero.", CWE369, Certainty::normal);
|
|
reportError(tok, Severity::error, "zerodivcond", ValueFlow::eitherTheConditionIsRedundant(nullptr) + " or there is division by zero.", CWE369, Certainty::normal);
|
|
return;
|
|
}
|
|
|
|
const ErrorPath errorPath = getErrorPath(tok, value, "Division by zero");
|
|
|
|
std::ostringstream errmsg;
|
|
if (value->condition) {
|
|
const int line = tok ? tok->linenr() : 0;
|
|
errmsg << ValueFlow::eitherTheConditionIsRedundant(value->condition)
|
|
<< " or there is division by zero at line " << line << ".";
|
|
} else
|
|
errmsg << "Division by zero.";
|
|
|
|
reportError(errorPath,
|
|
value->errorSeverity() ? Severity::error : Severity::warning,
|
|
value->condition ? "zerodivcond" : "zerodiv",
|
|
errmsg.str(), CWE369, value->isInconclusive() ? Certainty::inconclusive : Certainty::normal);
|
|
}
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Check for NaN (not-a-number) in an arithmetic expression, e.g.
|
|
// double d = 1.0 / 0.0 + 100.0;
|
|
//---------------------------------------------------------------------------
|
|
|
|
void CheckOther::checkNanInArithmeticExpression()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::style))
|
|
return;
|
|
for (const Token *tok = mTokenizer->tokens(); tok; tok = tok->next()) {
|
|
if (tok->str() != "/")
|
|
continue;
|
|
if (!Token::Match(tok->astParent(), "[+-]"))
|
|
continue;
|
|
if (Token::simpleMatch(tok->astOperand2(), "0.0"))
|
|
nanInArithmeticExpressionError(tok);
|
|
}
|
|
}
|
|
|
|
void CheckOther::nanInArithmeticExpressionError(const Token *tok)
|
|
{
|
|
reportError(tok, Severity::style, "nanInArithmeticExpression",
|
|
"Using NaN/Inf in a computation.\n"
|
|
"Using NaN/Inf in a computation. "
|
|
"Although nothing bad really happens, it is suspicious.", CWE369, Certainty::normal);
|
|
}
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Creating instance of classes which are destroyed immediately
|
|
//---------------------------------------------------------------------------
|
|
void CheckOther::checkMisusedScopedObject()
|
|
{
|
|
// Skip this check for .c files
|
|
if (mTokenizer->isC())
|
|
return;
|
|
|
|
if (!mSettings->severity.isEnabled(Severity::style))
|
|
return;
|
|
|
|
const SymbolDatabase * const symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
for (const Scope * scope : symbolDatabase->functionScopes) {
|
|
for (const Token *tok = scope->bodyStart; tok && tok != scope->bodyEnd; tok = tok->next()) {
|
|
if ((tok->next()->type() || (tok->next()->function() && tok->next()->function()->isConstructor())) // TODO: The rhs of || should be removed; It is a workaround for a symboldatabase bug
|
|
&& Token::Match(tok, "[;{}] %name% (")
|
|
&& Token::Match(tok->linkAt(2), ") ; !!}")
|
|
&& (!tok->next()->function() || // is not a function on this scope
|
|
tok->next()->function()->isConstructor())) { // or is function in this scope and it's a ctor
|
|
tok = tok->next();
|
|
misusedScopeObjectError(tok, tok->str());
|
|
tok = tok->next();
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckOther::misusedScopeObjectError(const Token *tok, const std::string& varname)
|
|
{
|
|
reportError(tok, Severity::style,
|
|
"unusedScopedObject",
|
|
"$symbol:" + varname + "\n"
|
|
"Instance of '$symbol' object is destroyed immediately.", CWE563, Certainty::normal);
|
|
}
|
|
|
|
static const Token * getSingleExpressionInBlock(const Token * tok)
|
|
{
|
|
if (!tok)
|
|
return nullptr;
|
|
const Token * top = tok->astTop();
|
|
if (!top)
|
|
return nullptr;
|
|
const Token * nextExpression = nextAfterAstRightmostLeaf(top);
|
|
if (!Token::simpleMatch(nextExpression, "; }"))
|
|
return nullptr;
|
|
return top;
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------
|
|
// check for duplicate code in if and else branches
|
|
// if (a) { b = true; } else { b = true; }
|
|
//-----------------------------------------------------------------------------
|
|
void CheckOther::checkDuplicateBranch()
|
|
{
|
|
// This is inconclusive since in practice most warnings are noise:
|
|
// * There can be unfixed low-priority todos. The code is fine as it
|
|
// is but it could be possible to enhance it. Writing a warning
|
|
// here is noise since the code is fine (see cppcheck, abiword, ..)
|
|
// * There can be overspecified code so some conditions can't be true
|
|
// and their conditional code is a duplicate of the condition that
|
|
// is always true just in case it would be false. See for instance
|
|
// abiword.
|
|
if (!mSettings->severity.isEnabled(Severity::style) || !mSettings->certainty.isEnabled(Certainty::inconclusive))
|
|
return;
|
|
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
|
|
for (const Scope & scope : symbolDatabase->scopeList) {
|
|
if (scope.type != Scope::eIf)
|
|
continue;
|
|
|
|
// check all the code in the function for if (..) else
|
|
if (Token::simpleMatch(scope.bodyEnd, "} else {")) {
|
|
// Make sure there are no macros (different macros might be expanded
|
|
// to the same code)
|
|
bool macro = false;
|
|
for (const Token *tok = scope.bodyStart; tok != scope.bodyEnd->linkAt(2); tok = tok->next()) {
|
|
if (tok->isExpandedMacro()) {
|
|
macro = true;
|
|
break;
|
|
}
|
|
}
|
|
if (macro)
|
|
continue;
|
|
|
|
// save if branch code
|
|
const std::string branch1 = scope.bodyStart->next()->stringifyList(scope.bodyEnd);
|
|
|
|
if (branch1.empty())
|
|
continue;
|
|
|
|
// save else branch code
|
|
const std::string branch2 = scope.bodyEnd->tokAt(3)->stringifyList(scope.bodyEnd->linkAt(2));
|
|
|
|
ErrorPath errorPath;
|
|
// check for duplicates
|
|
if (branch1 == branch2) {
|
|
duplicateBranchError(scope.classDef, scope.bodyEnd->next(), errorPath);
|
|
continue;
|
|
}
|
|
|
|
// check for duplicates using isSameExpression
|
|
const Token * branchTop1 = getSingleExpressionInBlock(scope.bodyStart->next());
|
|
const Token * branchTop2 = getSingleExpressionInBlock(scope.bodyEnd->tokAt(3));
|
|
if (!branchTop1 || !branchTop2)
|
|
continue;
|
|
if (branchTop1->str() != branchTop2->str())
|
|
continue;
|
|
if (isSameExpression(mTokenizer->isCPP(), false, branchTop1->astOperand1(), branchTop2->astOperand1(), mSettings->library, true, true, &errorPath) &&
|
|
isSameExpression(mTokenizer->isCPP(), false, branchTop1->astOperand2(), branchTop2->astOperand2(), mSettings->library, true, true, &errorPath))
|
|
duplicateBranchError(scope.classDef, scope.bodyEnd->next(), errorPath);
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckOther::duplicateBranchError(const Token *tok1, const Token *tok2, ErrorPath errors)
|
|
{
|
|
errors.emplace_back(tok2, "");
|
|
errors.emplace_back(tok1, "");
|
|
|
|
reportError(errors, Severity::style, "duplicateBranch", "Found duplicate branches for 'if' and 'else'.\n"
|
|
"Finding the same code in an 'if' and related 'else' branch is suspicious and "
|
|
"might indicate a cut and paste or logic error. Please examine this code "
|
|
"carefully to determine if it is correct.", CWE398, Certainty::inconclusive);
|
|
}
|
|
|
|
|
|
//-----------------------------------------------------------------------------
|
|
// Check for a free() of an invalid address
|
|
// char* p = malloc(100);
|
|
// free(p + 10);
|
|
//-----------------------------------------------------------------------------
|
|
void CheckOther::checkInvalidFree()
|
|
{
|
|
std::map<int, bool> inconclusive;
|
|
std::map<int, std::string> allocation;
|
|
|
|
const bool printInconclusive = mSettings->certainty.isEnabled(Certainty::inconclusive);
|
|
const SymbolDatabase* symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
for (const Scope * scope : symbolDatabase->functionScopes) {
|
|
for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
|
|
|
|
// Keep track of which variables were assigned addresses to newly-allocated memory
|
|
if (Token::Match(tok, "%var% = malloc|g_malloc|new")) {
|
|
allocation.insert(std::make_pair(tok->varId(), tok->strAt(2)));
|
|
inconclusive.insert(std::make_pair(tok->varId(), false));
|
|
}
|
|
|
|
// If a previously-allocated pointer is incremented or decremented, any subsequent
|
|
// free involving pointer arithmetic may or may not be invalid, so we should only
|
|
// report an inconclusive result.
|
|
else if (Token::Match(tok, "%var% = %name% +|-") &&
|
|
tok->varId() == tok->tokAt(2)->varId() &&
|
|
allocation.find(tok->varId()) != allocation.end()) {
|
|
if (printInconclusive)
|
|
inconclusive[tok->varId()] = true;
|
|
else {
|
|
allocation.erase(tok->varId());
|
|
inconclusive.erase(tok->varId());
|
|
}
|
|
}
|
|
|
|
// If a previously-allocated pointer is assigned a completely new value,
|
|
// we can't know if any subsequent free() on that pointer is valid or not.
|
|
else if (Token::Match(tok, "%var% =")) {
|
|
allocation.erase(tok->varId());
|
|
inconclusive.erase(tok->varId());
|
|
}
|
|
|
|
// If a variable that was previously assigned a newly-allocated memory location is
|
|
// added or subtracted from when used to free the memory, report an error.
|
|
else if (Token::Match(tok, "free|g_free|delete ( %any% +|-") ||
|
|
Token::Match(tok, "delete [ ] ( %any% +|-") ||
|
|
Token::Match(tok, "delete %any% +|- %any%")) {
|
|
|
|
const int varIndex = tok->strAt(1) == "(" ? 2 :
|
|
tok->strAt(3) == "(" ? 4 : 1;
|
|
const int var1 = tok->tokAt(varIndex)->varId();
|
|
const int var2 = tok->tokAt(varIndex + 2)->varId();
|
|
const std::map<int, bool>::const_iterator alloc1 = inconclusive.find(var1);
|
|
const std::map<int, bool>::const_iterator alloc2 = inconclusive.find(var2);
|
|
if (alloc1 != inconclusive.end()) {
|
|
invalidFreeError(tok, allocation[var1], alloc1->second);
|
|
} else if (alloc2 != inconclusive.end()) {
|
|
invalidFreeError(tok, allocation[var2], alloc2->second);
|
|
}
|
|
}
|
|
|
|
// If the previously-allocated variable is passed in to another function
|
|
// as a parameter, it might be modified, so we shouldn't report an error
|
|
// if it is later used to free memory
|
|
else if (Token::Match(tok, "%name% (") && !mSettings->library.isFunctionConst(tok->str(), true)) {
|
|
const Token* tok2 = Token::findmatch(tok->next(), "%var%", tok->linkAt(1));
|
|
while (tok2 != nullptr) {
|
|
allocation.erase(tok->varId());
|
|
inconclusive.erase(tok2->varId());
|
|
tok2 = Token::findmatch(tok2->next(), "%var%", tok->linkAt(1));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckOther::invalidFreeError(const Token *tok, const std::string &allocation, bool inconclusive)
|
|
{
|
|
std::string alloc = allocation;
|
|
if (alloc != "new")
|
|
alloc += "()";
|
|
std::string deallocated = (alloc == "new") ? "deleted" : "freed";
|
|
reportError(tok, Severity::error, "invalidFree", "Mismatching address is " + deallocated + ". The address you get from " + alloc + " must be " + deallocated + " without offset.", CWE(0U), inconclusive ? Certainty::inconclusive : Certainty::normal);
|
|
}
|
|
|
|
|
|
//---------------------------------------------------------------------------
|
|
// check for the same expression on both sides of an operator
|
|
// (x == x), (x && x), (x || x)
|
|
// (x.y == x.y), (x.y && x.y), (x.y || x.y)
|
|
//---------------------------------------------------------------------------
|
|
|
|
namespace {
|
|
bool notconst(const Function* func)
|
|
{
|
|
return !func->isConst();
|
|
}
|
|
|
|
void getConstFunctions(const SymbolDatabase *symbolDatabase, std::list<const Function*> &constFunctions)
|
|
{
|
|
for (const Scope &scope : symbolDatabase->scopeList) {
|
|
// only add const functions that do not have a non-const overloaded version
|
|
// since it is pretty much impossible to tell which is being called.
|
|
using StringFunctionMap = std::map<std::string, std::list<const Function*>>;
|
|
StringFunctionMap functionsByName;
|
|
for (const Function &func : scope.functionList) {
|
|
functionsByName[func.tokenDef->str()].push_back(&func);
|
|
}
|
|
for (std::pair<const std::string, std::list<const Function*>>& it : functionsByName) {
|
|
const std::list<const Function*>::const_iterator nc = std::find_if(it.second.begin(), it.second.end(), notconst);
|
|
if (nc == it.second.end()) {
|
|
// ok to add all of them
|
|
constFunctions.splice(constFunctions.end(), it.second);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckOther::checkDuplicateExpression()
|
|
{
|
|
const bool styleEnabled = mSettings->severity.isEnabled(Severity::style);
|
|
const bool warningEnabled = mSettings->severity.isEnabled(Severity::warning);
|
|
if (!styleEnabled && !warningEnabled)
|
|
return;
|
|
|
|
// Parse all executing scopes..
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
|
|
std::list<const Function*> constFunctions;
|
|
getConstFunctions(symbolDatabase, constFunctions);
|
|
|
|
for (const Scope *scope : symbolDatabase->functionScopes) {
|
|
for (const Token *tok = scope->bodyStart; tok != scope->bodyEnd; tok = tok->next()) {
|
|
if (tok->str() == "=" && Token::Match(tok->astOperand1(), "%var%")) {
|
|
const Token * endStatement = Token::findsimplematch(tok, ";");
|
|
if (Token::Match(endStatement, "; %type% %var% ;")) {
|
|
endStatement = endStatement->tokAt(4);
|
|
}
|
|
if (Token::Match(endStatement, "%var% %assign%")) {
|
|
const Token * nextAssign = endStatement->tokAt(1);
|
|
const Token * var1 = tok->astOperand1();
|
|
const Token * var2 = nextAssign->astOperand1();
|
|
if (var1 && var2 &&
|
|
Token::Match(var1->previous(), ";|{|} %var%") &&
|
|
Token::Match(var2->previous(), ";|{|} %var%") &&
|
|
var2->valueType() && var1->valueType() &&
|
|
var2->valueType()->originalTypeName == var1->valueType()->originalTypeName &&
|
|
var2->valueType()->pointer == var1->valueType()->pointer &&
|
|
var2->valueType()->constness == var1->valueType()->constness &&
|
|
var2->varId() != var1->varId() && (
|
|
tok->astOperand2()->isArithmeticalOp() ||
|
|
tok->astOperand2()->str() == "." ||
|
|
Token::Match(tok->astOperand2()->previous(), "%name% (")
|
|
) &&
|
|
tok->next()->tokType() != Token::eType &&
|
|
isSameExpression(mTokenizer->isCPP(), true, tok->next(), nextAssign->next(), mSettings->library, true, false) &&
|
|
isSameExpression(mTokenizer->isCPP(), true, tok->astOperand2(), nextAssign->astOperand2(), mSettings->library, true, false) &&
|
|
tok->astOperand2()->expressionString() == nextAssign->astOperand2()->expressionString()) {
|
|
bool differentDomain = false;
|
|
const Scope * varScope = var1->scope() ? var1->scope() : scope;
|
|
for (const Token *assignTok = Token::findsimplematch(var2, ";"); assignTok && assignTok != varScope->bodyEnd; assignTok = assignTok->next()) {
|
|
if (!Token::Match(assignTok, "%assign%|%comp%"))
|
|
continue;
|
|
if (!assignTok->astOperand1())
|
|
continue;
|
|
if (!assignTok->astOperand2())
|
|
continue;
|
|
|
|
if (assignTok->astOperand1()->varId() != var1->varId() &&
|
|
assignTok->astOperand1()->varId() != var2->varId() &&
|
|
!isSameExpression(mTokenizer->isCPP(),
|
|
true,
|
|
tok->astOperand2(),
|
|
assignTok->astOperand1(),
|
|
mSettings->library,
|
|
true,
|
|
true))
|
|
continue;
|
|
if (assignTok->astOperand2()->varId() != var1->varId() &&
|
|
assignTok->astOperand2()->varId() != var2->varId() &&
|
|
!isSameExpression(mTokenizer->isCPP(),
|
|
true,
|
|
tok->astOperand2(),
|
|
assignTok->astOperand2(),
|
|
mSettings->library,
|
|
true,
|
|
true))
|
|
continue;
|
|
differentDomain = true;
|
|
break;
|
|
}
|
|
if (!differentDomain && !isUniqueExpression(tok->astOperand2()))
|
|
duplicateAssignExpressionError(var1, var2, false);
|
|
else if (mSettings->certainty.isEnabled(Certainty::inconclusive))
|
|
duplicateAssignExpressionError(var1, var2, true);
|
|
}
|
|
}
|
|
}
|
|
ErrorPath errorPath;
|
|
if (tok->isOp() && tok->astOperand1() && !Token::Match(tok, "+|*|<<|>>|+=|*=|<<=|>>=")) {
|
|
if (Token::Match(tok, "==|!=|-") && astIsFloat(tok->astOperand1(), true))
|
|
continue;
|
|
const bool pointerDereference = (tok->astOperand1() && tok->astOperand1()->isUnaryOp("*")) ||
|
|
(tok->astOperand2() && tok->astOperand2()->isUnaryOp("*"));
|
|
const bool followVar = (!isConstVarExpression(tok) || Token::Match(tok, "%comp%|%oror%|&&")) && !pointerDereference;
|
|
if (isSameExpression(mTokenizer->isCPP(),
|
|
true,
|
|
tok->astOperand1(),
|
|
tok->astOperand2(),
|
|
mSettings->library,
|
|
true,
|
|
followVar,
|
|
&errorPath)) {
|
|
if (isWithoutSideEffects(mTokenizer->isCPP(), tok->astOperand1())) {
|
|
const bool assignment = tok->str() == "=";
|
|
if (assignment && warningEnabled)
|
|
selfAssignmentError(tok, tok->astOperand1()->expressionString());
|
|
else if (styleEnabled) {
|
|
if (mTokenizer->isCPP() && mSettings->standards.cpp >= Standards::CPP11 && tok->str() == "==") {
|
|
const Token* parent = tok->astParent();
|
|
while (parent && parent->astParent()) {
|
|
parent = parent->astParent();
|
|
}
|
|
if (parent && parent->previous() && parent->previous()->str() == "static_assert") {
|
|
continue;
|
|
}
|
|
}
|
|
duplicateExpressionError(tok->astOperand1(), tok->astOperand2(), tok, errorPath);
|
|
}
|
|
}
|
|
} else if (tok->str() == "=" && Token::simpleMatch(tok->astOperand2(), "=") &&
|
|
isSameExpression(mTokenizer->isCPP(),
|
|
false,
|
|
tok->astOperand1(),
|
|
tok->astOperand2()->astOperand1(),
|
|
mSettings->library,
|
|
true,
|
|
false)) {
|
|
if (warningEnabled && isWithoutSideEffects(mTokenizer->isCPP(), tok->astOperand1())) {
|
|
selfAssignmentError(tok, tok->astOperand1()->expressionString());
|
|
}
|
|
} else if (styleEnabled &&
|
|
isOppositeExpression(mTokenizer->isCPP(),
|
|
tok->astOperand1(),
|
|
tok->astOperand2(),
|
|
mSettings->library,
|
|
false,
|
|
true,
|
|
&errorPath) &&
|
|
!Token::Match(tok, "=|-|-=|/|/=") &&
|
|
isWithoutSideEffects(mTokenizer->isCPP(), tok->astOperand1())) {
|
|
oppositeExpressionError(tok, errorPath);
|
|
} else if (!Token::Match(tok, "[-/%]")) { // These operators are not associative
|
|
if (styleEnabled && tok->astOperand2() && tok->str() == tok->astOperand1()->str() &&
|
|
isSameExpression(mTokenizer->isCPP(),
|
|
true,
|
|
tok->astOperand2(),
|
|
tok->astOperand1()->astOperand2(),
|
|
mSettings->library,
|
|
true,
|
|
followVar,
|
|
&errorPath) &&
|
|
isWithoutSideEffects(mTokenizer->isCPP(), tok->astOperand2()))
|
|
duplicateExpressionError(tok->astOperand2(), tok->astOperand1()->astOperand2(), tok, errorPath);
|
|
else if (tok->astOperand2() && isConstExpression(tok->astOperand1(), mSettings->library, true, mTokenizer->isCPP())) {
|
|
const Token *ast1 = tok->astOperand1();
|
|
while (ast1 && tok->str() == ast1->str()) {
|
|
if (isSameExpression(mTokenizer->isCPP(), true, ast1->astOperand1(), tok->astOperand2(), mSettings->library, true, true, &errorPath) &&
|
|
isWithoutSideEffects(mTokenizer->isCPP(), ast1->astOperand1()) &&
|
|
isWithoutSideEffects(mTokenizer->isCPP(), ast1->astOperand2()))
|
|
// Probably the message should be changed to 'duplicate expressions X in condition or something like that'.
|
|
duplicateExpressionError(ast1->astOperand1(), tok->astOperand2(), tok, errorPath);
|
|
ast1 = ast1->astOperand1();
|
|
}
|
|
}
|
|
}
|
|
} else if (styleEnabled && tok->astOperand1() && tok->astOperand2() && tok->str() == ":" && tok->astParent() && tok->astParent()->str() == "?") {
|
|
if (!isVariableChanged(tok->astParent(), /*indirect*/ 0, mSettings, mTokenizer->isCPP()) && !tok->astOperand1()->values().empty() && !tok->astOperand2()->values().empty() && isEqualKnownValue(tok->astOperand1(), tok->astOperand2()))
|
|
duplicateValueTernaryError(tok);
|
|
else if (isSameExpression(mTokenizer->isCPP(), true, tok->astOperand1(), tok->astOperand2(), mSettings->library, false, true, &errorPath))
|
|
duplicateExpressionTernaryError(tok, errorPath);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckOther::oppositeExpressionError(const Token *opTok, ErrorPath errors)
|
|
{
|
|
errors.emplace_back(opTok, "");
|
|
|
|
const std::string& op = opTok ? opTok->str() : "&&";
|
|
|
|
reportError(errors, Severity::style, "oppositeExpression", "Opposite expression on both sides of \'" + op + "\'.\n"
|
|
"Finding the opposite expression on both sides of an operator is suspicious and might "
|
|
"indicate a cut and paste or logic error. Please examine this code carefully to "
|
|
"determine if it is correct.", CWE398, Certainty::normal);
|
|
}
|
|
|
|
void CheckOther::duplicateExpressionError(const Token *tok1, const Token *tok2, const Token *opTok, ErrorPath errors)
|
|
{
|
|
errors.emplace_back(opTok, "");
|
|
|
|
const std::string& expr1 = tok1 ? tok1->expressionString() : "x";
|
|
const std::string& expr2 = tok2 ? tok2->expressionString() : "x";
|
|
|
|
const std::string& op = opTok ? opTok->str() : "&&";
|
|
std::string msg = "Same expression on both sides of \'" + op + "\'";
|
|
const char *id = "duplicateExpression";
|
|
if (expr1 != expr2 && (!opTok || !opTok->isArithmeticalOp())) {
|
|
id = "knownConditionTrueFalse";
|
|
std::string exprMsg = "The comparison \'" + expr1 + " " + op + " " + expr2 + "\' is always ";
|
|
if (Token::Match(opTok, "==|>=|<="))
|
|
msg = exprMsg + "true";
|
|
else if (Token::Match(opTok, "!=|>|<"))
|
|
msg = exprMsg + "false";
|
|
if (!Token::Match(tok1, "%num%|NULL|nullptr") && !Token::Match(tok2, "%num%|NULL|nullptr"))
|
|
msg += " because '" + expr1 + "' and '" + expr2 + "' represent the same value";
|
|
}
|
|
|
|
reportError(errors, Severity::style, id, msg + ".\n"
|
|
"Finding the same expression on both sides of an operator is suspicious and might "
|
|
"indicate a cut and paste or logic error. Please examine this code carefully to "
|
|
"determine if it is correct.", CWE398, Certainty::normal);
|
|
}
|
|
|
|
void CheckOther::duplicateAssignExpressionError(const Token *tok1, const Token *tok2, bool inconclusive)
|
|
{
|
|
const std::list<const Token *> toks = { tok2, tok1 };
|
|
|
|
const std::string& var1 = tok1 ? tok1->str() : "x";
|
|
const std::string& var2 = tok2 ? tok2->str() : "x";
|
|
|
|
reportError(toks, Severity::style, "duplicateAssignExpression",
|
|
"Same expression used in consecutive assignments of '" + var1 + "' and '" + var2 + "'.\n"
|
|
"Finding variables '" + var1 + "' and '" + var2 + "' that are assigned the same expression "
|
|
"is suspicious and might indicate a cut and paste or logic error. Please examine this code carefully to "
|
|
"determine if it is correct.", CWE398, inconclusive ? Certainty::inconclusive : Certainty::normal);
|
|
}
|
|
|
|
void CheckOther::duplicateExpressionTernaryError(const Token *tok, ErrorPath errors)
|
|
{
|
|
errors.emplace_back(tok, "");
|
|
reportError(errors, Severity::style, "duplicateExpressionTernary", "Same expression in both branches of ternary operator.\n"
|
|
"Finding the same expression in both branches of ternary operator is suspicious as "
|
|
"the same code is executed regardless of the condition.", CWE398, Certainty::normal);
|
|
}
|
|
|
|
void CheckOther::duplicateValueTernaryError(const Token *tok)
|
|
{
|
|
reportError(tok, Severity::style, "duplicateValueTernary", "Same value in both branches of ternary operator.\n"
|
|
"Finding the same value in both branches of ternary operator is suspicious as "
|
|
"the same code is executed regardless of the condition.", CWE398, Certainty::normal);
|
|
}
|
|
|
|
void CheckOther::selfAssignmentError(const Token *tok, const std::string &varname)
|
|
{
|
|
reportError(tok, Severity::warning,
|
|
"selfAssignment",
|
|
"$symbol:" + varname + "\n"
|
|
"Redundant assignment of '$symbol' to itself.", CWE398, Certainty::normal);
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------
|
|
// Check is a comparison of two variables leads to condition, which is
|
|
// always true or false.
|
|
// For instance: int a = 1; if(isless(a,a)){...}
|
|
// In this case isless(a,a) always evaluates to false.
|
|
//
|
|
// Reference:
|
|
// - http://www.cplusplus.com/reference/cmath/
|
|
//-----------------------------------------------------------------------------
|
|
void CheckOther::checkComparisonFunctionIsAlwaysTrueOrFalse()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::warning))
|
|
return;
|
|
|
|
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->isName() && Token::Match(tok, "isgreater|isless|islessgreater|isgreaterequal|islessequal ( %var% , %var% )")) {
|
|
const int varidLeft = tok->tokAt(2)->varId();// get the left varid
|
|
const int varidRight = tok->tokAt(4)->varId();// get the right varid
|
|
// compare varids: if they are not zero but equal
|
|
// --> the comparison function is called with the same variables
|
|
if (varidLeft == varidRight) {
|
|
const std::string& functionName = tok->str(); // store function name
|
|
const std::string& varNameLeft = tok->strAt(2); // get the left variable name
|
|
if (functionName == "isgreater" || functionName == "isless" || functionName == "islessgreater") {
|
|
// e.g.: isgreater(x,x) --> (x)>(x) --> false
|
|
checkComparisonFunctionIsAlwaysTrueOrFalseError(tok, functionName, varNameLeft, false);
|
|
} else { // functionName == "isgreaterequal" || functionName == "islessequal"
|
|
// e.g.: isgreaterequal(x,x) --> (x)>=(x) --> true
|
|
checkComparisonFunctionIsAlwaysTrueOrFalseError(tok, functionName, varNameLeft, true);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
void CheckOther::checkComparisonFunctionIsAlwaysTrueOrFalseError(const Token* tok, const std::string &functionName, const std::string &varName, const bool result)
|
|
{
|
|
const std::string strResult = result ? "true" : "false";
|
|
const struct CWE cweResult = result ? CWE571 : CWE570;
|
|
|
|
reportError(tok, Severity::warning, "comparisonFunctionIsAlwaysTrueOrFalse",
|
|
"$symbol:" + functionName + "\n"
|
|
"Comparison of two identical variables with $symbol(" + varName + "," + varName + ") always evaluates to " + strResult + ".\n"
|
|
"The function $symbol is designed to compare two variables. Calling this function with one variable (" + varName + ") "
|
|
"for both parameters leads to a statement which is always " + strResult + ".", cweResult, Certainty::normal);
|
|
}
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Check testing sign of unsigned variables and pointers.
|
|
//---------------------------------------------------------------------------
|
|
void CheckOther::checkSignOfUnsignedVariable()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::style))
|
|
return;
|
|
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
|
|
for (const Scope * scope : symbolDatabase->functionScopes) {
|
|
// check all the code in the function
|
|
for (const Token *tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
|
|
const ValueFlow::Value *zeroValue = nullptr;
|
|
const Token *nonZeroExpr = nullptr;
|
|
if (comparisonNonZeroExpressionLessThanZero(tok, &zeroValue, &nonZeroExpr)) {
|
|
const ValueType* vt = nonZeroExpr->valueType();
|
|
if (vt->pointer)
|
|
pointerLessThanZeroError(tok, zeroValue);
|
|
else
|
|
unsignedLessThanZeroError(tok, zeroValue, nonZeroExpr->expressionString());
|
|
} else if (testIfNonZeroExpressionIsPositive(tok, &zeroValue, &nonZeroExpr)) {
|
|
const ValueType* vt = nonZeroExpr->valueType();
|
|
if (vt->pointer)
|
|
pointerPositiveError(tok, zeroValue);
|
|
else
|
|
unsignedPositiveError(tok, zeroValue, nonZeroExpr->expressionString());
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
bool CheckOther::comparisonNonZeroExpressionLessThanZero(const Token *tok, const ValueFlow::Value **zeroValue, const Token **nonZeroExpr)
|
|
{
|
|
if (!tok->isComparisonOp() || !tok->astOperand1() || !tok->astOperand2())
|
|
return false;
|
|
|
|
const ValueFlow::Value *v1 = tok->astOperand1()->getValue(0);
|
|
const ValueFlow::Value *v2 = tok->astOperand2()->getValue(0);
|
|
|
|
if (Token::Match(tok, "<|<=") && v2 && v2->isKnown()) {
|
|
*zeroValue = v2;
|
|
*nonZeroExpr = tok->astOperand1();
|
|
} else if (Token::Match(tok, ">|>=") && v1 && v1->isKnown()) {
|
|
*zeroValue = v1;
|
|
*nonZeroExpr = tok->astOperand2();
|
|
} else {
|
|
return false;
|
|
}
|
|
|
|
const ValueType* vt = (*nonZeroExpr)->valueType();
|
|
return vt && (vt->pointer || vt->sign == ValueType::UNSIGNED);
|
|
}
|
|
|
|
bool CheckOther::testIfNonZeroExpressionIsPositive(const Token *tok, const ValueFlow::Value **zeroValue, const Token **nonZeroExpr)
|
|
{
|
|
if (!tok->isComparisonOp() || !tok->astOperand1() || !tok->astOperand2())
|
|
return false;
|
|
|
|
const ValueFlow::Value *v1 = tok->astOperand1()->getValue(0);
|
|
const ValueFlow::Value *v2 = tok->astOperand2()->getValue(0);
|
|
|
|
if (Token::simpleMatch(tok, ">=") && v2 && v2->isKnown()) {
|
|
*zeroValue = v2;
|
|
*nonZeroExpr = tok->astOperand1();
|
|
} else if (Token::simpleMatch(tok, "<=") && v1 && v1->isKnown()) {
|
|
*zeroValue = v1;
|
|
*nonZeroExpr = tok->astOperand2();
|
|
} else {
|
|
return false;
|
|
}
|
|
|
|
const ValueType* vt = (*nonZeroExpr)->valueType();
|
|
return vt && (vt->pointer || vt->sign == ValueType::UNSIGNED);
|
|
}
|
|
|
|
void CheckOther::unsignedLessThanZeroError(const Token *tok, const ValueFlow::Value * v, const std::string &varname)
|
|
{
|
|
reportError(getErrorPath(tok, v, "Unsigned less than zero"), Severity::style, "unsignedLessThanZero",
|
|
"$symbol:" + varname + "\n"
|
|
"Checking if unsigned expression '$symbol' is less than zero.\n"
|
|
"The unsigned expression '$symbol' will never be negative so it "
|
|
"is either pointless or an error to check if it is.", CWE570, Certainty::normal);
|
|
}
|
|
|
|
void CheckOther::pointerLessThanZeroError(const Token *tok, const ValueFlow::Value *v)
|
|
{
|
|
reportError(getErrorPath(tok, v, "Pointer less than zero"), Severity::style, "pointerLessThanZero",
|
|
"A pointer can not be negative so it is either pointless or an error to check if it is.", CWE570, Certainty::normal);
|
|
}
|
|
|
|
void CheckOther::unsignedPositiveError(const Token *tok, const ValueFlow::Value * v, const std::string &varname)
|
|
{
|
|
reportError(getErrorPath(tok, v, "Unsigned positive"), Severity::style, "unsignedPositive",
|
|
"$symbol:" + varname + "\n"
|
|
"Unsigned expression '$symbol' can't be negative so it is unnecessary to test it.", CWE570, Certainty::normal);
|
|
}
|
|
|
|
void CheckOther::pointerPositiveError(const Token *tok, const ValueFlow::Value * v)
|
|
{
|
|
reportError(getErrorPath(tok, v, "Pointer positive"), Severity::style, "pointerPositive",
|
|
"A pointer can not be negative so it is either pointless or an error to check if it is not.", CWE570, Certainty::normal);
|
|
}
|
|
|
|
/* check if a constructor in given class scope takes a reference */
|
|
static bool constructorTakesReference(const Scope * const classScope)
|
|
{
|
|
for (const Function &constructor : classScope->functionList) {
|
|
if (constructor.isConstructor()) {
|
|
for (int argnr = 0U; argnr < constructor.argCount(); argnr++) {
|
|
const Variable * const argVar = constructor.getArgumentVar(argnr);
|
|
if (argVar && argVar->isReference()) {
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
//---------------------------------------------------------------------------
|
|
// This check rule works for checking the "const A a = getA()" usage when getA() returns "const A &" or "A &".
|
|
// In most scenarios, "const A & a = getA()" will be more efficient.
|
|
//---------------------------------------------------------------------------
|
|
void CheckOther::checkRedundantCopy()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::performance) || mTokenizer->isC() || !mSettings->certainty.isEnabled(Certainty::inconclusive))
|
|
return;
|
|
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
|
|
for (const Variable* var : symbolDatabase->variableList()) {
|
|
if (!var || var->isReference() || !var->isConst() || var->isPointer() || (!var->type() && !var->isStlType())) // bailout if var is of standard type, if it is a pointer or non-const
|
|
continue;
|
|
|
|
const Token* startTok = var->nameToken();
|
|
if (startTok->strAt(1) == "=") // %type% %name% = ... ;
|
|
;
|
|
else if (startTok->strAt(1) == "(" && var->isClass() && var->typeScope()) {
|
|
// Object is instantiated. Warn if constructor takes arguments by value.
|
|
if (constructorTakesReference(var->typeScope()))
|
|
continue;
|
|
} else
|
|
continue;
|
|
|
|
const Token* tok = startTok->next()->astOperand2();
|
|
if (!tok)
|
|
continue;
|
|
if (!Token::Match(tok->previous(), "%name% ("))
|
|
continue;
|
|
if (!Token::Match(tok->link(), ") )| ;")) // bailout for usage like "const A a = getA()+3"
|
|
continue;
|
|
|
|
const Function* func = tok->previous()->function();
|
|
if (func && func->tokenDef->strAt(-1) == "&") {
|
|
redundantCopyError(startTok, startTok->str());
|
|
}
|
|
}
|
|
}
|
|
void CheckOther::redundantCopyError(const Token *tok,const std::string& varname)
|
|
{
|
|
reportError(tok, Severity::performance, "redundantCopyLocalConst",
|
|
"$symbol:" + varname + "\n"
|
|
"Use const reference for '$symbol' to avoid unnecessary data copying.\n"
|
|
"The const variable '$symbol' is assigned a copy of the data. You can avoid "
|
|
"the unnecessary data copying by converting '$symbol' to const reference.",
|
|
CWE398,
|
|
Certainty::inconclusive); // since #5618 that check became inconclusive
|
|
}
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Checking for shift by negative values
|
|
//---------------------------------------------------------------------------
|
|
|
|
static bool isNegative(const Token *tok, const Settings *settings)
|
|
{
|
|
return tok->valueType() && tok->valueType()->sign == ValueType::SIGNED && tok->getValueLE(-1LL, settings);
|
|
}
|
|
|
|
void CheckOther::checkNegativeBitwiseShift()
|
|
{
|
|
const bool portability = mSettings->severity.isEnabled(Severity::portability);
|
|
|
|
for (const Token* tok = mTokenizer->tokens(); tok; tok = tok->next()) {
|
|
if (!tok->astOperand1() || !tok->astOperand2())
|
|
continue;
|
|
|
|
if (!Token::Match(tok, "<<|>>|<<=|>>="))
|
|
continue;
|
|
|
|
// don't warn if lhs is a class. this is an overloaded operator then
|
|
if (mTokenizer->isCPP()) {
|
|
const ValueType * lhsType = tok->astOperand1()->valueType();
|
|
if (!lhsType || !lhsType->isIntegral())
|
|
continue;
|
|
}
|
|
|
|
// bailout if operation is protected by ?:
|
|
bool ternary = false;
|
|
for (const Token *parent = tok; parent; parent = parent->astParent()) {
|
|
if (Token::Match(parent, "?|:")) {
|
|
ternary = true;
|
|
break;
|
|
}
|
|
}
|
|
if (ternary)
|
|
continue;
|
|
|
|
// Get negative rhs value. preferably a value which doesn't have 'condition'.
|
|
if (portability && isNegative(tok->astOperand1(), mSettings))
|
|
negativeBitwiseShiftError(tok, 1);
|
|
else if (isNegative(tok->astOperand2(), mSettings))
|
|
negativeBitwiseShiftError(tok, 2);
|
|
}
|
|
}
|
|
|
|
|
|
void CheckOther::negativeBitwiseShiftError(const Token *tok, int op)
|
|
{
|
|
if (op == 1)
|
|
// LHS - this is used by intention in various software, if it
|
|
// is used often in a project and works as expected then this is
|
|
// a portability issue
|
|
reportError(tok, Severity::portability, "shiftNegativeLHS", "Shifting a negative value is technically undefined behaviour", CWE758, Certainty::normal);
|
|
else // RHS
|
|
reportError(tok, Severity::error, "shiftNegative", "Shifting by a negative value is undefined behaviour", CWE758, Certainty::normal);
|
|
}
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Check for incompletely filled buffers.
|
|
//---------------------------------------------------------------------------
|
|
void CheckOther::checkIncompleteArrayFill()
|
|
{
|
|
if (!mSettings->certainty.isEnabled(Certainty::inconclusive))
|
|
return;
|
|
const bool printWarning = mSettings->severity.isEnabled(Severity::warning);
|
|
const bool printPortability = mSettings->severity.isEnabled(Severity::portability);
|
|
if (!printPortability && !printWarning)
|
|
return;
|
|
|
|
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, "memset|memcpy|memmove ( %var% ,") && Token::Match(tok->linkAt(1)->tokAt(-2), ", %num% )")) {
|
|
const Variable *var = tok->tokAt(2)->variable();
|
|
if (!var || !var->isArray() || var->dimensions().empty() || !var->dimension(0))
|
|
continue;
|
|
|
|
if (MathLib::toLongNumber(tok->linkAt(1)->strAt(-1)) == var->dimension(0)) {
|
|
int size = mTokenizer->sizeOfType(var->typeStartToken());
|
|
if (size == 0 && var->valueType()->pointer)
|
|
size = mSettings->sizeof_pointer;
|
|
else if (size == 0 && var->type())
|
|
size = estimateSize(var->type(), mSettings, symbolDatabase);
|
|
if ((size != 1 && size != 100 && size != 0) || var->isPointer()) {
|
|
if (printWarning)
|
|
incompleteArrayFillError(tok, var->name(), tok->str(), false);
|
|
} else if (var->valueType()->type == ValueType::Type::BOOL && printPortability) // sizeof(bool) is not 1 on all platforms
|
|
incompleteArrayFillError(tok, var->name(), tok->str(), true);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckOther::incompleteArrayFillError(const Token* tok, const std::string& buffer, const std::string& function, bool boolean)
|
|
{
|
|
if (boolean)
|
|
reportError(tok, Severity::portability, "incompleteArrayFill",
|
|
"$symbol:" + buffer + "\n"
|
|
"$symbol:" + function + "\n"
|
|
"Array '" + buffer + "' might be filled incompletely. Did you forget to multiply the size given to '" + function + "()' with 'sizeof(*" + buffer + ")'?\n"
|
|
"The array '" + buffer + "' is filled incompletely. The function '" + function + "()' needs the size given in bytes, but the type 'bool' is larger than 1 on some platforms. Did you forget to multiply the size with 'sizeof(*" + buffer + ")'?", CWE131, Certainty::inconclusive);
|
|
else
|
|
reportError(tok, Severity::warning, "incompleteArrayFill",
|
|
"$symbol:" + buffer + "\n"
|
|
"$symbol:" + function + "\n"
|
|
"Array '" + buffer + "' is filled incompletely. Did you forget to multiply the size given to '" + function + "()' with 'sizeof(*" + buffer + ")'?\n"
|
|
"The array '" + buffer + "' is filled incompletely. The function '" + function + "()' needs the size given in bytes, but an element of the given array is larger than one byte. Did you forget to multiply the size with 'sizeof(*" + buffer + ")'?", CWE131, Certainty::inconclusive);
|
|
}
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Detect NULL being passed to variadic function.
|
|
//---------------------------------------------------------------------------
|
|
|
|
void CheckOther::checkVarFuncNullUB()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::portability))
|
|
return;
|
|
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
for (const Scope * scope : symbolDatabase->functionScopes) {
|
|
for (const Token* tok = scope->bodyStart; tok != scope->bodyEnd; tok = tok->next()) {
|
|
// Is NULL passed to a function?
|
|
if (Token::Match(tok,"[(,] NULL [,)]")) {
|
|
// Locate function name in this function call.
|
|
const Token *ftok = tok;
|
|
int argnr = 1;
|
|
while (ftok && ftok->str() != "(") {
|
|
if (ftok->str() == ")")
|
|
ftok = ftok->link();
|
|
else if (ftok->str() == ",")
|
|
++argnr;
|
|
ftok = ftok->previous();
|
|
}
|
|
ftok = ftok ? ftok->previous() : nullptr;
|
|
if (ftok && ftok->isName()) {
|
|
// If this is a variadic function then report error
|
|
const Function *f = ftok->function();
|
|
if (f && f->argCount() <= argnr) {
|
|
const Token *tok2 = f->argDef;
|
|
tok2 = tok2 ? tok2->link() : nullptr; // goto ')'
|
|
if (tok2 && Token::simpleMatch(tok2->tokAt(-1), "..."))
|
|
varFuncNullUBError(tok);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckOther::varFuncNullUBError(const Token *tok)
|
|
{
|
|
reportError(tok,
|
|
Severity::portability,
|
|
"varFuncNullUB",
|
|
"Passing NULL after the last typed argument to a variadic function leads to undefined behaviour.\n"
|
|
"Passing NULL after the last typed argument to a variadic function leads to undefined behaviour.\n"
|
|
"The C99 standard, in section 7.15.1.1, states that if the type used by va_arg() is not compatible with the type of the actual next argument (as promoted according to the default argument promotions), the behavior is undefined.\n"
|
|
"The value of the NULL macro is an implementation-defined null pointer constant (7.17), which can be any integer constant expression with the value 0, or such an expression casted to (void*) (6.3.2.3). This includes values like 0, 0L, or even 0LL.\n"
|
|
"In practice on common architectures, this will cause real crashes if sizeof(int) != sizeof(void*), and NULL is defined to 0 or any other null pointer constant that promotes to int.\n"
|
|
"To reproduce you might be able to use this little code example on 64bit platforms. If the output includes \"ERROR\", the sentinel had only 4 out of 8 bytes initialized to zero and was not detected as the final argument to stop argument processing via va_arg(). Changing the 0 to (void*)0 or 0L will make the \"ERROR\" output go away.\n"
|
|
"#include <stdarg.h>\n"
|
|
"#include <stdio.h>\n"
|
|
"\n"
|
|
"void f(char *s, ...) {\n"
|
|
" va_list ap;\n"
|
|
" va_start(ap,s);\n"
|
|
" for (;;) {\n"
|
|
" char *p = va_arg(ap,char*);\n"
|
|
" printf(\"%018p, %s\\n\", p, (long)p & 255 ? p : \"\");\n"
|
|
" if(!p) break;\n"
|
|
" }\n"
|
|
" va_end(ap);\n"
|
|
"}\n"
|
|
"\n"
|
|
"void g() {\n"
|
|
" char *s2 = \"x\";\n"
|
|
" char *s3 = \"ERROR\";\n"
|
|
"\n"
|
|
" // changing 0 to 0L for the 7th argument (which is intended to act as sentinel) makes the error go away on x86_64\n"
|
|
" f(\"first\", s2, s2, s2, s2, s2, 0, s3, (char*)0);\n"
|
|
"}\n"
|
|
"\n"
|
|
"void h() {\n"
|
|
" int i;\n"
|
|
" volatile unsigned char a[1000];\n"
|
|
" for (i = 0; i<sizeof(a); i++)\n"
|
|
" a[i] = -1;\n"
|
|
"}\n"
|
|
"\n"
|
|
"int main() {\n"
|
|
" h();\n"
|
|
" g();\n"
|
|
" return 0;\n"
|
|
"}", CWE475, Certainty::normal);
|
|
}
|
|
|
|
void CheckOther::checkRedundantPointerOp()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::style))
|
|
return;
|
|
|
|
for (const Token *tok = mTokenizer->tokens(); tok; tok = tok->next()) {
|
|
if (tok->isExpandedMacro() && tok->str() == "(")
|
|
tok = tok->link();
|
|
|
|
if (!tok->isUnaryOp("&") || !tok->astOperand1()->isUnaryOp("*"))
|
|
continue;
|
|
|
|
// variable
|
|
const Token *varTok = tok->astOperand1()->astOperand1();
|
|
if (!varTok || varTok->isExpandedMacro())
|
|
continue;
|
|
|
|
const Variable *var = varTok->variable();
|
|
if (!var || !var->isPointer())
|
|
continue;
|
|
|
|
redundantPointerOpError(tok, var->name(), false);
|
|
}
|
|
}
|
|
|
|
void CheckOther::redundantPointerOpError(const Token* tok, const std::string &varname, bool inconclusive)
|
|
{
|
|
reportError(tok, Severity::style, "redundantPointerOp",
|
|
"$symbol:" + varname + "\n"
|
|
"Redundant pointer operation on '$symbol' - it's already a pointer.", CWE398, inconclusive ? Certainty::inconclusive : Certainty::normal);
|
|
}
|
|
|
|
void CheckOther::checkInterlockedDecrement()
|
|
{
|
|
if (!mSettings->isWindowsPlatform()) {
|
|
return;
|
|
}
|
|
|
|
for (const Token *tok = mTokenizer->tokens(); tok; tok = tok->next()) {
|
|
if (tok->isName() && Token::Match(tok, "InterlockedDecrement ( & %name% ) ; if ( %name%|!|0")) {
|
|
const Token* interlockedVarTok = tok->tokAt(3);
|
|
const Token* checkStartTok = interlockedVarTok->tokAt(5);
|
|
if ((Token::Match(checkStartTok, "0 %comp% %name% )") && checkStartTok->strAt(2) == interlockedVarTok->str()) ||
|
|
(Token::Match(checkStartTok, "! %name% )") && checkStartTok->strAt(1) == interlockedVarTok->str()) ||
|
|
(Token::Match(checkStartTok, "%name% )") && checkStartTok->str() == interlockedVarTok->str()) ||
|
|
(Token::Match(checkStartTok, "%name% %comp% 0 )") && checkStartTok->str() == interlockedVarTok->str())) {
|
|
raceAfterInterlockedDecrementError(checkStartTok);
|
|
}
|
|
} else if (Token::Match(tok, "if ( ::| InterlockedDecrement ( & %name%")) {
|
|
const Token* condEnd = tok->next()->link();
|
|
const Token* funcTok = tok->tokAt(2);
|
|
const Token* firstAccessTok = funcTok->str() == "::" ? funcTok->tokAt(4) : funcTok->tokAt(3);
|
|
if (condEnd && condEnd->next() && condEnd->next()->link()) {
|
|
const Token* ifEndTok = condEnd->next()->link();
|
|
if (Token::Match(ifEndTok, "} return %name%")) {
|
|
const Token* secondAccessTok = ifEndTok->tokAt(2);
|
|
if (secondAccessTok->str() == firstAccessTok->str()) {
|
|
raceAfterInterlockedDecrementError(secondAccessTok);
|
|
}
|
|
} else if (Token::Match(ifEndTok, "} else { return %name%")) {
|
|
const Token* secondAccessTok = ifEndTok->tokAt(4);
|
|
if (secondAccessTok->str() == firstAccessTok->str()) {
|
|
raceAfterInterlockedDecrementError(secondAccessTok);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckOther::raceAfterInterlockedDecrementError(const Token* tok)
|
|
{
|
|
reportError(tok, Severity::error, "raceAfterInterlockedDecrement",
|
|
"Race condition: non-interlocked access after InterlockedDecrement(). Use InterlockedDecrement() return value instead.", CWE362, Certainty::normal);
|
|
}
|
|
|
|
void CheckOther::checkUnusedLabel()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::style) && !mSettings->severity.isEnabled(Severity::warning))
|
|
return;
|
|
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
for (const Scope * scope : symbolDatabase->functionScopes) {
|
|
const bool hasIfdef = mTokenizer->hasIfdef(scope->bodyStart, scope->bodyEnd);
|
|
for (const Token* tok = scope->bodyStart; tok != scope->bodyEnd; tok = tok->next()) {
|
|
if (!tok->scope()->isExecutable())
|
|
tok = tok->scope()->bodyEnd;
|
|
|
|
if (Token::Match(tok, "{|}|; %name% :") && tok->strAt(1) != "default") {
|
|
const std::string tmp("goto " + tok->strAt(1));
|
|
if (!Token::findsimplematch(scope->bodyStart->next(), tmp.c_str(), tmp.size(), scope->bodyEnd->previous()))
|
|
unusedLabelError(tok->next(), tok->next()->scope()->type == Scope::eSwitch, hasIfdef);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckOther::unusedLabelError(const Token* tok, bool inSwitch, bool hasIfdef)
|
|
{
|
|
if (tok && !mSettings->severity.isEnabled(inSwitch ? Severity::warning : Severity::style))
|
|
return;
|
|
|
|
std::string id = "unusedLabel";
|
|
if (inSwitch)
|
|
id += "Switch";
|
|
if (hasIfdef)
|
|
id += "Configuration";
|
|
|
|
std::string msg = "$symbol:" + (tok ? tok->str() : emptyString) + "\nLabel '$symbol' is not used.";
|
|
if (hasIfdef)
|
|
msg += " There is #if in function body so the label might be used in code that is removed by the preprocessor.";
|
|
if (inSwitch)
|
|
msg += " Should this be a 'case' of the enclosing switch()?";
|
|
|
|
reportError(tok,
|
|
inSwitch ? Severity::warning : Severity::style,
|
|
id,
|
|
msg,
|
|
CWE398,
|
|
Certainty::normal);
|
|
}
|
|
|
|
|
|
void CheckOther::checkEvaluationOrder()
|
|
{
|
|
// This checker is not written according to C++11 sequencing rules
|
|
if (mTokenizer->isCPP() && mSettings->standards.cpp >= Standards::CPP11)
|
|
return;
|
|
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
for (const Scope * functionScope : symbolDatabase->functionScopes) {
|
|
for (const Token* tok = functionScope->bodyStart; tok != functionScope->bodyEnd; tok = tok->next()) {
|
|
if (!Token::Match(tok, "++|--") && !tok->isAssignmentOp())
|
|
continue;
|
|
if (!tok->astOperand1())
|
|
continue;
|
|
for (const Token *tok2 = tok;; tok2 = tok2->astParent()) {
|
|
// If ast parent is a sequence point then break
|
|
const Token * const parent = tok2->astParent();
|
|
if (!parent)
|
|
break;
|
|
if (Token::Match(parent, "%oror%|&&|?|:|;"))
|
|
break;
|
|
if (parent->str() == ",") {
|
|
const Token *par = parent;
|
|
while (Token::simpleMatch(par,","))
|
|
par = par->astParent();
|
|
// not function or in a while clause => break
|
|
if (!(par && par->str() == "(" && par->astOperand2() && par->strAt(-1) != "while"))
|
|
break;
|
|
// control flow (if|while|etc) => break
|
|
if (Token::simpleMatch(par->link(),") {"))
|
|
break;
|
|
// sequence point in function argument: dostuff((1,2),3) => break
|
|
par = par->next();
|
|
while (par && (par->previous() != parent))
|
|
par = par->nextArgument();
|
|
if (!par)
|
|
break;
|
|
}
|
|
if (parent->str() == "(" && parent->astOperand2())
|
|
break;
|
|
|
|
// self assignment..
|
|
if (tok2 == tok &&
|
|
tok->str() == "=" &&
|
|
parent->str() == "=" &&
|
|
isSameExpression(mTokenizer->isCPP(), false, tok->astOperand1(), parent->astOperand1(), mSettings->library, true, false)) {
|
|
if (mSettings->severity.isEnabled(Severity::warning) &&
|
|
isSameExpression(mTokenizer->isCPP(), true, tok->astOperand1(), parent->astOperand1(), mSettings->library, true, false))
|
|
selfAssignmentError(parent, tok->astOperand1()->expressionString());
|
|
break;
|
|
}
|
|
|
|
// Is expression used?
|
|
bool foundError = false;
|
|
visitAstNodes((parent->astOperand1() != tok2) ? parent->astOperand1() : parent->astOperand2(),
|
|
[&](const Token *tok3) {
|
|
if (tok3->str() == "&" && !tok3->astOperand2())
|
|
return ChildrenToVisit::none; // don't handle address-of for now
|
|
if (tok3->str() == "(" && Token::simpleMatch(tok3->previous(), "sizeof"))
|
|
return ChildrenToVisit::none; // don't care about sizeof usage
|
|
if (isSameExpression(mTokenizer->isCPP(), false, tok->astOperand1(), tok3, mSettings->library, true, false))
|
|
foundError = true;
|
|
return foundError ? ChildrenToVisit::done : ChildrenToVisit::op1_and_op2;
|
|
});
|
|
|
|
if (foundError) {
|
|
unknownEvaluationOrder(parent);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckOther::unknownEvaluationOrder(const Token* tok)
|
|
{
|
|
reportError(tok, Severity::error, "unknownEvaluationOrder",
|
|
"Expression '" + (tok ? tok->expressionString() : std::string("x = x++;")) + "' depends on order of evaluation of side effects", CWE768, Certainty::normal);
|
|
}
|
|
|
|
void CheckOther::checkAccessOfMovedVariable()
|
|
{
|
|
if (!mTokenizer->isCPP() || mSettings->standards.cpp < Standards::CPP11 || !mSettings->severity.isEnabled(Severity::warning))
|
|
return;
|
|
CheckUninitVar checkUninitVar(mTokenizer, mSettings, mErrorLogger);
|
|
const bool reportInconclusive = mSettings->certainty.isEnabled(Certainty::inconclusive);
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
for (const Scope * scope : symbolDatabase->functionScopes) {
|
|
const Token * scopeStart = scope->bodyStart;
|
|
if (scope->function) {
|
|
const Token * memberInitializationStart = scope->function->constructorMemberInitialization();
|
|
if (memberInitializationStart)
|
|
scopeStart = memberInitializationStart;
|
|
}
|
|
for (const Token* tok = scopeStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
|
|
const ValueFlow::Value * movedValue = tok->getMovedValue();
|
|
if (!movedValue || movedValue->moveKind == ValueFlow::Value::MoveKind::NonMovedVariable)
|
|
continue;
|
|
if (movedValue->isInconclusive() && !reportInconclusive)
|
|
continue;
|
|
|
|
bool inconclusive = false;
|
|
bool accessOfMoved = false;
|
|
if (tok->strAt(1) == ".") {
|
|
if (tok->next()->originalName() == "->")
|
|
accessOfMoved = true;
|
|
else
|
|
inconclusive = true;
|
|
} else {
|
|
const bool variableChanged = isVariableChangedByFunctionCall(tok, 0, mSettings, &inconclusive);
|
|
accessOfMoved = !variableChanged && checkUninitVar.isVariableUsage(tok, false, CheckUninitVar::NO_ALLOC);
|
|
if (inconclusive) {
|
|
accessOfMoved = !isMovedParameterAllowedForInconclusiveFunction(tok);
|
|
if (accessOfMoved)
|
|
inconclusive = false;
|
|
}
|
|
}
|
|
if (accessOfMoved || (inconclusive && reportInconclusive))
|
|
accessMovedError(tok, tok->str(), movedValue, inconclusive || movedValue->isInconclusive());
|
|
}
|
|
}
|
|
}
|
|
|
|
bool CheckOther::isMovedParameterAllowedForInconclusiveFunction(const Token * tok)
|
|
{
|
|
if (Token::simpleMatch(tok->tokAt(-4), "std :: move ("))
|
|
return false;
|
|
const Token * tokAtM2 = tok->tokAt(-2);
|
|
if (Token::simpleMatch(tokAtM2, "> (") && tokAtM2->link()) {
|
|
const Token * leftAngle = tokAtM2->link();
|
|
if (Token::simpleMatch(leftAngle->tokAt(-3), "std :: forward <"))
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
void CheckOther::accessMovedError(const Token *tok, const std::string &varname, const ValueFlow::Value *value, bool inconclusive)
|
|
{
|
|
if (!tok) {
|
|
reportError(tok, Severity::warning, "accessMoved", "Access of moved variable 'v'.", CWE672, Certainty::normal);
|
|
reportError(tok, Severity::warning, "accessForwarded", "Access of forwarded variable 'v'.", CWE672, Certainty::normal);
|
|
return;
|
|
}
|
|
|
|
const char * errorId = nullptr;
|
|
std::string kindString;
|
|
switch (value->moveKind) {
|
|
case ValueFlow::Value::MoveKind::MovedVariable:
|
|
errorId = "accessMoved";
|
|
kindString = "moved";
|
|
break;
|
|
case ValueFlow::Value::MoveKind::ForwardedVariable:
|
|
errorId = "accessForwarded";
|
|
kindString = "forwarded";
|
|
break;
|
|
default:
|
|
return;
|
|
}
|
|
const std::string errmsg("$symbol:" + varname + "\nAccess of " + kindString + " variable '$symbol'.");
|
|
const ErrorPath errorPath = getErrorPath(tok, value, errmsg);
|
|
reportError(errorPath, Severity::warning, errorId, errmsg, CWE672, inconclusive ? Certainty::inconclusive : Certainty::normal);
|
|
}
|
|
|
|
|
|
|
|
void CheckOther::checkFuncArgNamesDifferent()
|
|
{
|
|
const bool style = mSettings->severity.isEnabled(Severity::style);
|
|
const bool inconclusive = mSettings->certainty.isEnabled(Certainty::inconclusive);
|
|
const bool warning = mSettings->severity.isEnabled(Severity::warning);
|
|
|
|
if (!(warning || (style && inconclusive)))
|
|
return;
|
|
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
// check every function
|
|
for (const Scope *scope : symbolDatabase->functionScopes) {
|
|
const Function * function = scope->function;
|
|
// only check functions with arguments
|
|
if (!function || function->argCount() == 0)
|
|
continue;
|
|
|
|
// only check functions with separate declarations and definitions
|
|
if (function->argDef == function->arg)
|
|
continue;
|
|
|
|
// get the function argument name tokens
|
|
std::vector<const Token *> declarations(function->argCount());
|
|
std::vector<const Token *> definitions(function->argCount());
|
|
const Token * decl = function->argDef->next();
|
|
for (int j = 0; j < function->argCount(); ++j) {
|
|
declarations[j] = nullptr;
|
|
definitions[j] = nullptr;
|
|
// get the definition
|
|
const Variable * variable = function->getArgumentVar(j);
|
|
if (variable) {
|
|
definitions[j] = variable->nameToken();
|
|
}
|
|
// get the declaration (search for first token with varId)
|
|
while (decl && !Token::Match(decl, ",|)|;")) {
|
|
// skip everything after the assignment because
|
|
// it could also have a varId or be the first
|
|
// token with a varId if there is no name token
|
|
if (decl->str() == "=") {
|
|
decl = decl->nextArgument();
|
|
break;
|
|
}
|
|
// skip over template
|
|
if (decl->link())
|
|
decl = decl->link();
|
|
else if (decl->varId())
|
|
declarations[j] = decl;
|
|
decl = decl->next();
|
|
}
|
|
if (Token::simpleMatch(decl, ","))
|
|
decl = decl->next();
|
|
}
|
|
// check for different argument order
|
|
if (warning) {
|
|
bool order_different = false;
|
|
for (int j = 0; j < function->argCount(); ++j) {
|
|
if (!declarations[j] || !definitions[j] || declarations[j]->str() == definitions[j]->str())
|
|
continue;
|
|
|
|
for (int k = 0; k < function->argCount(); ++k) {
|
|
if (j != k && definitions[k] && declarations[j]->str() == definitions[k]->str()) {
|
|
order_different = true;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
if (order_different) {
|
|
funcArgOrderDifferent(function->name(), function->argDef->next(), function->arg->next(), declarations, definitions);
|
|
continue;
|
|
}
|
|
}
|
|
// check for different argument names
|
|
if (style && inconclusive) {
|
|
for (int j = 0; j < function->argCount(); ++j) {
|
|
if (declarations[j] && definitions[j] && declarations[j]->str() != definitions[j]->str())
|
|
funcArgNamesDifferent(function->name(), j, declarations[j], definitions[j]);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckOther::funcArgNamesDifferent(const std::string & functionName, nonneg int index,
|
|
const Token* declaration, const Token* definition)
|
|
{
|
|
std::list<const Token *> tokens = { declaration,definition };
|
|
reportError(tokens, Severity::style, "funcArgNamesDifferent",
|
|
"$symbol:" + functionName + "\n"
|
|
"Function '$symbol' argument " + MathLib::toString(index + 1) + " names different: declaration '" +
|
|
(declaration ? declaration->str() : std::string("A")) + "' definition '" +
|
|
(definition ? definition->str() : std::string("B")) + "'.", CWE628, Certainty::inconclusive);
|
|
}
|
|
|
|
void CheckOther::funcArgOrderDifferent(const std::string & functionName,
|
|
const Token* declaration, const Token* definition,
|
|
const std::vector<const Token *> & declarations,
|
|
const std::vector<const Token *> & definitions)
|
|
{
|
|
std::list<const Token *> tokens = {
|
|
declarations.size() ? declarations[0] ? declarations[0] : declaration : nullptr,
|
|
definitions.size() ? definitions[0] ? definitions[0] : definition : nullptr
|
|
};
|
|
std::string msg = "$symbol:" + functionName + "\nFunction '$symbol' argument order different: declaration '";
|
|
for (int i = 0; i < declarations.size(); ++i) {
|
|
if (i != 0)
|
|
msg += ", ";
|
|
if (declarations[i])
|
|
msg += declarations[i]->str();
|
|
}
|
|
msg += "' definition '";
|
|
for (int i = 0; i < definitions.size(); ++i) {
|
|
if (i != 0)
|
|
msg += ", ";
|
|
if (definitions[i])
|
|
msg += definitions[i]->str();
|
|
}
|
|
msg += "'";
|
|
reportError(tokens, Severity::warning, "funcArgOrderDifferent", msg, CWE683, Certainty::normal);
|
|
}
|
|
|
|
static const Token *findShadowed(const Scope *scope, const std::string &varname, int linenr)
|
|
{
|
|
if (!scope)
|
|
return nullptr;
|
|
for (const Variable &var : scope->varlist) {
|
|
if (scope->isExecutable() && var.nameToken()->linenr() > linenr)
|
|
continue;
|
|
if (var.name() == varname)
|
|
return var.nameToken();
|
|
}
|
|
for (const Function &f : scope->functionList) {
|
|
if (f.type == Function::Type::eFunction && f.name() == varname)
|
|
return f.tokenDef;
|
|
}
|
|
if (scope->type == Scope::eLambda)
|
|
return nullptr;
|
|
return findShadowed(scope->nestedIn, varname, linenr);
|
|
}
|
|
|
|
void CheckOther::checkShadowVariables()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::style))
|
|
return;
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
for (const Scope & scope : symbolDatabase->scopeList) {
|
|
if (!scope.isExecutable() || scope.type == Scope::eLambda)
|
|
continue;
|
|
const Scope *functionScope = &scope;
|
|
while (functionScope && functionScope->type != Scope::ScopeType::eFunction && functionScope->type != Scope::ScopeType::eLambda)
|
|
functionScope = functionScope->nestedIn;
|
|
for (const Variable &var : scope.varlist) {
|
|
if (var.nameToken() && var.nameToken()->isExpandedMacro()) // #8903
|
|
continue;
|
|
|
|
if (functionScope && functionScope->type == Scope::ScopeType::eFunction && functionScope->function) {
|
|
bool shadowArg = false;
|
|
for (const Variable &arg : functionScope->function->argumentList) {
|
|
if (arg.nameToken() && var.name() == arg.name()) {
|
|
shadowError(var.nameToken(), arg.nameToken(), "argument");
|
|
shadowArg = true;
|
|
break;
|
|
}
|
|
}
|
|
if (shadowArg)
|
|
continue;
|
|
}
|
|
|
|
const Token *shadowed = findShadowed(scope.nestedIn, var.name(), var.nameToken()->linenr());
|
|
if (!shadowed)
|
|
continue;
|
|
if (scope.type == Scope::eFunction && scope.className == var.name())
|
|
continue;
|
|
shadowError(var.nameToken(), shadowed, (shadowed->varId() != 0) ? "variable" : "function");
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckOther::shadowError(const Token *var, const Token *shadowed, std::string type)
|
|
{
|
|
ErrorPath errorPath;
|
|
errorPath.push_back(ErrorPathItem(shadowed, "Shadowed declaration"));
|
|
errorPath.push_back(ErrorPathItem(var, "Shadow variable"));
|
|
const std::string &varname = var ? var->str() : type;
|
|
const std::string Type = char(std::toupper(type[0])) + type.substr(1);
|
|
const std::string id = "shadow" + Type;
|
|
const std::string message = "$symbol:" + varname + "\nLocal variable \'$symbol\' shadows outer " + type;
|
|
reportError(errorPath, Severity::style, id.c_str(), message, CWE398, Certainty::normal);
|
|
}
|
|
|
|
static bool isVariableExpression(const Token* tok)
|
|
{
|
|
if (Token::Match(tok, "%var%"))
|
|
return true;
|
|
if (Token::simpleMatch(tok, "."))
|
|
return isVariableExpression(tok->astOperand1()) &&
|
|
isVariableExpression(tok->astOperand2());
|
|
if (Token::simpleMatch(tok, "["))
|
|
return isVariableExpression(tok->astOperand1()) &&
|
|
tok->astOperand2() && tok->astOperand2()->hasKnownIntValue();
|
|
return false;
|
|
}
|
|
|
|
void CheckOther::checkKnownArgument()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::style))
|
|
return;
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
for (const Scope *functionScope : symbolDatabase->functionScopes) {
|
|
for (const Token *tok = functionScope->bodyStart; tok != functionScope->bodyEnd; tok = tok->next()) {
|
|
if (!Token::simpleMatch(tok->astParent(), "("))
|
|
continue;
|
|
if (!Token::Match(tok->astParent()->previous(), "%name%"))
|
|
continue;
|
|
if (Token::Match(tok->astParent()->previous(), "if|while|switch|sizeof"))
|
|
continue;
|
|
if (tok == tok->astParent()->previous())
|
|
continue;
|
|
if (!tok->hasKnownIntValue())
|
|
continue;
|
|
if (Token::Match(tok, "++|--"))
|
|
continue;
|
|
if (isConstVarExpression(tok))
|
|
continue;
|
|
const Token * tok2 = tok;
|
|
if (isCPPCast(tok2))
|
|
tok2 = tok2->astOperand2();
|
|
if (isVariableExpression(tok2))
|
|
continue;
|
|
// ensure that there is a integer variable in expression with unknown value
|
|
std::string varexpr;
|
|
bool isVariableExprHidden = false; // Is variable expression explicitly hidden
|
|
auto setVarExpr = [&varexpr, &isVariableExprHidden](const Token *child) {
|
|
if (Token::Match(child, "%var%|.|[")) {
|
|
if (child->valueType() && child->valueType()->pointer == 0 && child->valueType()->isIntegral() && child->values().empty()) {
|
|
varexpr = child->expressionString();
|
|
return ChildrenToVisit::done;
|
|
}
|
|
return ChildrenToVisit::none;
|
|
}
|
|
if (Token::simpleMatch(child->previous(), "sizeof ("))
|
|
return ChildrenToVisit::none;
|
|
|
|
// hide variable explicitly with 'x * 0' etc
|
|
if (!isVariableExprHidden) {
|
|
if (Token::simpleMatch(child, "*") && (Token::simpleMatch(child->astOperand1(), "0") || Token::simpleMatch(child->astOperand2(), "0")))
|
|
return ChildrenToVisit::none;
|
|
if (Token::simpleMatch(child, "&&") && (Token::simpleMatch(child->astOperand1(), "false") || Token::simpleMatch(child->astOperand2(), "false")))
|
|
return ChildrenToVisit::none;
|
|
if (Token::simpleMatch(child, "||") && (Token::simpleMatch(child->astOperand1(), "true") || Token::simpleMatch(child->astOperand2(), "true")))
|
|
return ChildrenToVisit::none;
|
|
}
|
|
|
|
return ChildrenToVisit::op1_and_op2;
|
|
};
|
|
visitAstNodes(tok, setVarExpr);
|
|
if (varexpr.empty()) {
|
|
isVariableExprHidden = true;
|
|
visitAstNodes(tok, setVarExpr);
|
|
}
|
|
if (varexpr.empty())
|
|
continue;
|
|
// ensure that function name does not contain "assert"
|
|
std::string funcname = tok->astParent()->previous()->str();
|
|
std::transform(funcname.begin(), funcname.end(), funcname.begin(), [](int c) {
|
|
return std::tolower(c);
|
|
});
|
|
if (funcname.find("assert") != std::string::npos)
|
|
continue;
|
|
knownArgumentError(tok, tok->astParent()->previous(), &tok->values().front(), varexpr, isVariableExprHidden);
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckOther::knownArgumentError(const Token *tok, const Token *ftok, const ValueFlow::Value *value, const std::string &varexpr, bool isVariableExpressionHidden)
|
|
{
|
|
if (!tok) {
|
|
reportError(tok, Severity::style, "knownArgument", "Argument 'x-x' to function 'func' is always 0. It does not matter what value 'x' has.");
|
|
reportError(tok, Severity::style, "knownArgumentHiddenVariableExpression", "Argument 'x*0' to function 'func' is always 0. Constant literal calculation disable/hide variable expression 'x'.");
|
|
return;
|
|
}
|
|
|
|
const MathLib::bigint intvalue = value->intvalue;
|
|
const std::string &expr = tok->expressionString();
|
|
const std::string &fun = ftok->str();
|
|
|
|
const char *id;
|
|
std::string errmsg = "Argument '" + expr + "' to function " + fun + " is always " + std::to_string(intvalue) + ". ";
|
|
if (!isVariableExpressionHidden) {
|
|
id = "knownArgument";
|
|
errmsg += "It does not matter what value '" + varexpr + "' has.";
|
|
} else {
|
|
id = "knownArgumentHiddenVariableExpression";
|
|
errmsg += "Constant literal calculation disable/hide variable expression '" + varexpr + "'.";
|
|
}
|
|
|
|
const ErrorPath errorPath = getErrorPath(tok, value, errmsg);
|
|
reportError(errorPath, Severity::style, id, errmsg, CWE570, Certainty::normal);
|
|
}
|
|
|
|
void CheckOther::checkComparePointers()
|
|
{
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
for (const Scope *functionScope : symbolDatabase->functionScopes) {
|
|
for (const Token *tok = functionScope->bodyStart; tok != functionScope->bodyEnd; tok = tok->next()) {
|
|
if (!Token::Match(tok, "<|>|<=|>=|-"))
|
|
continue;
|
|
const Token *tok1 = tok->astOperand1();
|
|
const Token *tok2 = tok->astOperand2();
|
|
if (!astIsPointer(tok1) || !astIsPointer(tok2))
|
|
continue;
|
|
ValueFlow::Value v1 = getLifetimeObjValue(tok1);
|
|
ValueFlow::Value v2 = getLifetimeObjValue(tok2);
|
|
if (!v1.isLocalLifetimeValue() || !v2.isLocalLifetimeValue())
|
|
continue;
|
|
const Variable *var1 = v1.tokvalue->variable();
|
|
const Variable *var2 = v2.tokvalue->variable();
|
|
if (!var1 || !var2)
|
|
continue;
|
|
if (v1.tokvalue->varId() == v2.tokvalue->varId())
|
|
continue;
|
|
if (var1->isReference() || var2->isReference())
|
|
continue;
|
|
if (var1->isRValueReference() || var2->isRValueReference())
|
|
continue;
|
|
comparePointersError(tok, &v1, &v2);
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckOther::comparePointersError(const Token *tok, const ValueFlow::Value *v1, const ValueFlow::Value *v2)
|
|
{
|
|
ErrorPath errorPath;
|
|
std::string verb = "Comparing";
|
|
if (Token::simpleMatch(tok, "-"))
|
|
verb = "Subtracting";
|
|
if (v1) {
|
|
errorPath.emplace_back(v1->tokvalue->variable()->nameToken(), "Variable declared here.");
|
|
errorPath.insert(errorPath.end(), v1->errorPath.begin(), v1->errorPath.end());
|
|
}
|
|
if (v2) {
|
|
errorPath.emplace_back(v2->tokvalue->variable()->nameToken(), "Variable declared here.");
|
|
errorPath.insert(errorPath.end(), v2->errorPath.begin(), v2->errorPath.end());
|
|
}
|
|
errorPath.emplace_back(tok, "");
|
|
reportError(
|
|
errorPath, Severity::error, "comparePointers", verb + " pointers that point to different objects", CWE570, Certainty::normal);
|
|
}
|
|
|
|
void CheckOther::checkModuloOfOne()
|
|
{
|
|
if (!mSettings->severity.isEnabled(Severity::style))
|
|
return;
|
|
|
|
for (const Token *tok = mTokenizer->tokens(); tok; tok = tok->next()) {
|
|
if (!tok->astOperand2() || !tok->astOperand1())
|
|
continue;
|
|
if (tok->str() != "%")
|
|
continue;
|
|
if (!tok->valueType() || !tok->valueType()->isIntegral())
|
|
continue;
|
|
|
|
// Value flow..
|
|
const ValueFlow::Value *value = tok->astOperand2()->getValue(1LL);
|
|
if (value && value->isKnown())
|
|
checkModuloOfOneError(tok);
|
|
}
|
|
}
|
|
|
|
void CheckOther::checkModuloOfOneError(const Token *tok)
|
|
{
|
|
reportError(tok, Severity::style, "moduloofone", "Modulo of one is always equal to zero");
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------
|
|
// Overlapping write (undefined behavior)
|
|
//-----------------------------------------------------------------------------
|
|
static bool getBufAndOffset(const Token *expr, const Token **buf, MathLib::bigint *offset)
|
|
{
|
|
if (!expr)
|
|
return false;
|
|
const Token *bufToken, *offsetToken;
|
|
if (expr->isUnaryOp("&") && Token::simpleMatch(expr->astOperand1(), "[")) {
|
|
bufToken = expr->astOperand1()->astOperand1();
|
|
offsetToken = expr->astOperand1()->astOperand2();
|
|
} else if (Token::Match(expr, "+|-") && expr->isBinaryOp()) {
|
|
const bool pointer1 = (expr->astOperand1()->valueType() && expr->astOperand1()->valueType()->pointer > 0);
|
|
const bool pointer2 = (expr->astOperand2()->valueType() && expr->astOperand2()->valueType()->pointer > 0);
|
|
if (pointer1 && !pointer2) {
|
|
bufToken = expr->astOperand1();
|
|
offsetToken = expr->astOperand2();
|
|
} else if (!pointer1 && pointer2) {
|
|
bufToken = expr->astOperand2();
|
|
offsetToken = expr->astOperand1();
|
|
} else {
|
|
return false;
|
|
}
|
|
} else if (expr->valueType() && expr->valueType()->pointer > 0) {
|
|
*buf = expr;
|
|
*offset = 0;
|
|
return true;
|
|
} else {
|
|
return false;
|
|
}
|
|
if (!bufToken->valueType() || !bufToken->valueType()->pointer)
|
|
return false;
|
|
if (!offsetToken->hasKnownIntValue())
|
|
return false;
|
|
*buf = bufToken;
|
|
*offset = offsetToken->getKnownIntValue();
|
|
return true;
|
|
}
|
|
|
|
void CheckOther::checkOverlappingWrite()
|
|
{
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
for (const Scope *functionScope : symbolDatabase->functionScopes) {
|
|
for (const Token *tok = functionScope->bodyStart; tok != functionScope->bodyEnd; tok = tok->next()) {
|
|
if (tok->isAssignmentOp()) {
|
|
// check if LHS is a union member..
|
|
const Token * const lhs = tok->astOperand1();
|
|
if (!Token::simpleMatch(lhs, ".") || !lhs->isBinaryOp())
|
|
continue;
|
|
const Variable * const lhsvar = lhs->astOperand1()->variable();
|
|
if (!lhsvar || !lhsvar->typeScope() || lhsvar->typeScope()->type != Scope::ScopeType::eUnion)
|
|
continue;
|
|
const Token* const lhsmember = lhs->astOperand2();
|
|
if (!lhsmember)
|
|
continue;
|
|
|
|
// Is other union member used in RHS?
|
|
const Token *errorToken = nullptr;
|
|
visitAstNodes(tok->astOperand2(), [lhsvar, lhsmember, &errorToken](const Token *rhs) {
|
|
if (!Token::simpleMatch(rhs, "."))
|
|
return ChildrenToVisit::op1_and_op2;
|
|
if (!rhs->isBinaryOp() || rhs->astOperand1()->variable() != lhsvar)
|
|
return ChildrenToVisit::none;
|
|
if (lhsmember->str() == rhs->astOperand2()->str())
|
|
return ChildrenToVisit::none;
|
|
errorToken = rhs->astOperand2();
|
|
return ChildrenToVisit::done;
|
|
});
|
|
if (errorToken)
|
|
overlappingWriteUnion(tok);
|
|
} else if (Token::Match(tok, "%name% (")) {
|
|
const Library::NonOverlappingData *nonOverlappingData = mSettings->library.getNonOverlappingData(tok);
|
|
if (!nonOverlappingData)
|
|
continue;
|
|
const std::vector<const Token *> args = getArguments(tok);
|
|
if (nonOverlappingData->ptr1Arg <= 0 || nonOverlappingData->ptr1Arg > args.size())
|
|
continue;
|
|
if (nonOverlappingData->ptr2Arg <= 0 || nonOverlappingData->ptr2Arg > args.size())
|
|
continue;
|
|
|
|
const Token *ptr1 = args[nonOverlappingData->ptr1Arg - 1];
|
|
if (ptr1->hasKnownIntValue() && ptr1->getKnownIntValue() == 0)
|
|
continue;
|
|
|
|
const Token *ptr2 = args[nonOverlappingData->ptr2Arg - 1];
|
|
if (ptr2->hasKnownIntValue() && ptr2->getKnownIntValue() == 0)
|
|
continue;
|
|
|
|
// TODO: nonOverlappingData->strlenArg
|
|
if (nonOverlappingData->sizeArg <= 0 || nonOverlappingData->sizeArg > args.size()) {
|
|
if (nonOverlappingData->sizeArg == -1) {
|
|
ErrorPath errorPath;
|
|
const bool macro = true;
|
|
const bool pure = true;
|
|
const bool follow = true;
|
|
if (!isSameExpression(mTokenizer->isCPP(), macro, ptr1, ptr2, mSettings->library, pure, follow, &errorPath))
|
|
continue;
|
|
overlappingWriteFunction(tok);
|
|
}
|
|
continue;
|
|
}
|
|
if (!args[nonOverlappingData->sizeArg-1]->hasKnownIntValue())
|
|
continue;
|
|
const MathLib::bigint sizeValue = args[nonOverlappingData->sizeArg-1]->getKnownIntValue();
|
|
const Token *buf1, *buf2;
|
|
MathLib::bigint offset1, offset2;
|
|
if (!getBufAndOffset(ptr1, &buf1, &offset1))
|
|
continue;
|
|
if (!getBufAndOffset(ptr2, &buf2, &offset2))
|
|
continue;
|
|
|
|
if (offset1 < offset2 && offset1 + sizeValue <= offset2)
|
|
continue;
|
|
if (offset2 < offset1 && offset2 + sizeValue <= offset1)
|
|
continue;
|
|
|
|
ErrorPath errorPath;
|
|
const bool macro = true;
|
|
const bool pure = true;
|
|
const bool follow = true;
|
|
if (!isSameExpression(mTokenizer->isCPP(), macro, buf1, buf2, mSettings->library, pure, follow, &errorPath))
|
|
continue;
|
|
overlappingWriteFunction(tok);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckOther::overlappingWriteUnion(const Token *tok)
|
|
{
|
|
reportError(tok, Severity::error, "overlappingWriteUnion", "Overlapping read/write of union is undefined behavior");
|
|
}
|
|
|
|
void CheckOther::overlappingWriteFunction(const Token *tok)
|
|
{
|
|
const std::string funcname = tok ? tok->str() : "";
|
|
reportError(tok, Severity::error, "overlappingWriteFunction", "Overlapping read/write in " + funcname + "() is undefined behavior");
|
|
}
|