/*

* Cppcheck - A tool for static C/C++ code analysis

* Copyright (C) 2007-2026 Cppcheck team.

*

* This program is free software: you can redistribute it and/or modify

* it under the terms of the GNU General Public License as published by

* the Free Software Foundation, either version 3 of the License, or

* (at your option) any later version.

*

* This program is distributed in the hope that it will be useful,

* but WITHOUT ANY WARRANTY; without even the implied warranty of

* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

* GNU General Public License for more details.

*

* You should have received a copy of the GNU General Public License

* along with this program. If not, see <http://www.gnu.org/licenses/>.

*/

//---------------------------------------------------------------------------

#include "checkother.h"

#include "astutils.h"

#include "fwdanalysis.h"

#include "library.h"

#include "mathlib.h"

#include "platform.h"

#include "settings.h"

#include "standards.h"

#include "symboldatabase.h"

#include "token.h"

#include "tokenize.h"

#include "tokenlist.h"

#include "utils.h"

#include "valueflow.h"

#include "vfvalue.h"

#include <algorithm> // find_if()

#include <cassert>

#include <cctype>

#include <cstddef>

#include <cstdint>

#include <list>

#include <map>

#include <set>

#include <sstream>

#include <unordered_map>

#include <utility>

//---------------------------------------------------------------------------

static const CWE CWE128(128U); // Wrap-around Error

static const CWE CWE131(131U); // Incorrect Calculation of Buffer Size

static const CWE CWE197(197U); // Numeric Truncation Error

static const CWE CWE362(362U); // Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

static const CWE CWE369(369U); // Divide By Zero

static const CWE CWE398(398U); // Indicator of Poor Code Quality

static const CWE CWE475(475U); // Undefined Behavior for Input to API

static const CWE CWE561(561U); // Dead Code

static const CWE CWE563(563U); // Assignment to Variable without Use ('Unused Variable')

static const CWE CWE570(570U); // Expression is Always False

static const CWE CWE571(571U); // Expression is Always True

static const CWE CWE672(672U); // Operation on a Resource after Expiration or Release

static const CWE CWE628(628U); // Function Call with Incorrectly Specified Arguments

static const CWE CWE683(683U); // Function Call With Incorrect Order of Arguments

static const CWE CWE704(704U); // Incorrect Type Conversion or Cast

static const CWE CWE758(758U); // Reliance on Undefined, Unspecified, or Implementation-Defined Behavior

static const CWE CWE768(768U); // Incorrect Short Circuit Evaluation

static const CWE CWE783(783U); // Operator Precedence Logic Error

//----------------------------------------------------------------------------------

// The return value of fgetc(), getc(), ungetc(), getchar() etc. is an integer value.

// If this return value is stored in a character variable and then compared

// to EOF, which is an integer, the comparison maybe be false.

//

// Reference:

// - Ticket #160

// - http://www.cplusplus.com/reference/cstdio/fgetc/

// - http://www.cplusplus.com/reference/cstdio/getc/

// - http://www.cplusplus.com/reference/cstdio/getchar/

// - http://www.cplusplus.com/reference/cstdio/ungetc/ ...

//----------------------------------------------------------------------------------

void CheckOtherImpl::checkCastIntToCharAndBack()

{

if (!mSettings.severity.isEnabled(Severity::warning))

return;

logChecker("CheckOther::checkCastIntToCharAndBack"); // warning

const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();

for (const Scope * scope : symbolDatabase->functionScopes) {

std::map<int, std::string> vars;

for (const Token* tok = scope->bodyStart->next(); tok && tok != scope->bodyEnd; tok = tok->next()) {

// Quick check to see if any of the matches below have any chances

if (!Token::Match(tok, "%var%|EOF %comp%|="))

continue;

if (Token::Match(tok, "%var% = fclose|fflush|fputc|fputs|fscanf|getchar|getc|fgetc|putchar|putc|puts|scanf|sscanf|ungetc (")) {

const Variable *var = tok->variable();

if (var && var->typeEndToken()->str() == "char" && !var->typeEndToken()->isSigned()) {

vars[tok->varId()] = tok->strAt(2);

}

} else if (Token::Match(tok, "EOF %comp% ( %var% = fclose|fflush|fputc|fputs|fscanf|getchar|getc|fgetc|putchar|putc|puts|scanf|sscanf|ungetc (")) {

tok = tok->tokAt(3);

const Variable *var = tok->variable();

if (var && var->typeEndToken()->str() == "char" && !var->typeEndToken()->isSigned()) {

checkCastIntToCharAndBackError(tok, tok->strAt(2));

}

} else if (tok->isCpp() && (Token::Match(tok, "EOF %comp% ( %var% = std :: cin . get (") || Token::Match(tok, "EOF %comp% ( %var% = cin . get ("))) {

tok = tok->tokAt(3);

const Variable *var = tok->variable();

if (var && var->typeEndToken()->str() == "char" && !var->typeEndToken()->isSigned()) {

checkCastIntToCharAndBackError(tok, "cin.get");

}

} else if (tok->isCpp() && (Token::Match(tok, "%var% = std :: cin . get (") || Token::Match(tok, "%var% = cin . get ("))) {

const Variable *var = tok->variable();

if (var && var->typeEndToken()->str() == "char" && !var->typeEndToken()->isSigned()) {

vars[tok->varId()] = "cin.get";

}

} else if (Token::Match(tok, "%var% %comp% EOF")) {

if (vars.find(tok->varId()) != vars.end()) {

checkCastIntToCharAndBackError(tok, vars[tok->varId()]);

}

} else if (Token::Match(tok, "EOF %comp% %var%")) {

tok = tok->tokAt(2);

if (vars.find(tok->varId()) != vars.end()) {

checkCastIntToCharAndBackError(tok, vars[tok->varId()]);

}

}

}

}

}

void CheckOtherImpl::checkCastIntToCharAndBackError(const Token *tok, const std::string &strFunctionName)

{

reportError(

tok,

Severity::warning,

"checkCastIntToCharAndBack",

"$symbol:" + strFunctionName + "\n"

"Storing $symbol() return value in char variable and then comparing with EOF.\n"

"When saving $symbol() return value in char variable there is loss of precision. "

" When $symbol() returns EOF this value is truncated. Comparing the char "

"variable with EOF can have unexpected results. For instance a loop \"while (EOF != (c = $symbol());\" "

"loops forever on some compilers/platforms and on other compilers/platforms it will stop "

"when the file contains a matching character.", CWE197, Certainty::normal

);

}

//---------------------------------------------------------------------------

// Clarify calculation precedence for ternary operators.

//---------------------------------------------------------------------------

void CheckOtherImpl::clarifyCalculation()

{

if (!mSettings.severity.isEnabled(Severity::style) && !mSettings.isPremiumEnabled("clarifyCalculation"))

return;

logChecker("CheckOther::clarifyCalculation"); // style

const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();

for (const Scope * scope : symbolDatabase->functionScopes) {

for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {

// ? operator where lhs is arithmetical expression

if (tok->str() != "?" || !tok->astOperand1() || !tok->astOperand1()->isCalculation())

continue;

if (!tok->astOperand1()->isArithmeticalOp() && tok->astOperand1()->tokType() != Token::eBitOp)

continue;

// non-pointer calculation in lhs and pointer in rhs => no clarification is needed

if (tok->astOperand1()->isBinaryOp() && Token::Match(tok->astOperand1(), "%or%|&|%|*|/") && tok->astOperand2()->valueType() && tok->astOperand2()->valueType()->pointer > 0)

continue;

// bit operation in lhs and char literals in rhs => probably no mistake

if (tok->astOperand1()->tokType() == Token::eBitOp && Token::Match(tok->astOperand2()->astOperand1(), "%char%") && Token::Match(tok->astOperand2()->astOperand2(), "%char%"))

continue;

// 2nd operand in lhs has known integer value => probably no mistake

if (tok->astOperand1()->isBinaryOp() && tok->astOperand1()->astOperand2()->hasKnownIntValue()) {

const Token *op = tok->astOperand1()->astOperand2();

if (op->isNumber())

continue;

if (op->valueType() && op->valueType()->isEnum())

continue;

}

// Is code clarified by parentheses already?

const Token *tok2 = tok->astOperand1();

for (; tok2; tok2 = tok2->next()) {

if (tok2->str() == "(")

tok2 = tok2->link();

else if (tok2->str() == ")")

break;

else if (tok2->str() == "?") {

clarifyCalculationError(tok, tok->astOperand1()->str());

break;

}

}

}

}

}

void CheckOtherImpl::clarifyCalculationError(const Token *tok, const std::string &op)

{

// suspicious calculation

const std::string calc("'a" + op + "b?c:d'");

// recommended calculation #1

const std::string s1("'(a" + op + "b)?c:d'");

// recommended calculation #2

const std::string s2("'a" + op + "(b?c:d)'");

reportError(tok,

Severity::style,

"clarifyCalculation",

"Clarify calculation precedence for '" + op + "' and '?'.\n"

"Suspicious calculation. Please use parentheses to clarify the code. "

"The code '" + calc + "' should be written as either '" + s1 + "' or '" + s2 + "'.", CWE783, Certainty::normal);

}

//---------------------------------------------------------------------------

// Clarify (meaningless) statements like *foo++; with parentheses.

//---------------------------------------------------------------------------

void CheckOtherImpl::clarifyStatement()

{

if (!mSettings.severity.isEnabled(Severity::warning))

return;

logChecker("CheckOther::clarifyStatement"); // warning

const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();

for (const Scope * scope : symbolDatabase->functionScopes) {

for (const Token* tok = scope->bodyStart; tok && tok != scope->bodyEnd; tok = tok->next()) {

if (tok->astOperand1() && Token::Match(tok, "* %name%")) {

const Token *tok2 = tok->previous();

while (tok2 && tok2->str() == "*")

tok2 = tok2->previous();

if (tok2 && !tok2->astParent() && Token::Match(tok2, "[{};]")) {

tok2 = tok->astOperand1();

if (Token::Match(tok2, "++|-- [;,]"))

clarifyStatementError(tok2);

}

}

}

}

}

void CheckOtherImpl::clarifyStatementError(const Token *tok)

{

reportError(tok, Severity::warning, "clarifyStatement", "In expression like '*A++' the result of '*' is unused. Did you intend to write '(*A)++;'?\n"

"A statement like '*A++;' might not do what you intended. Postfix 'operator++' is executed before 'operator*'. "

"Thus, the dereference is meaningless. Did you intend to write '(*A)++;'?", CWE783, Certainty::normal);

}

//---------------------------------------------------------------------------

// Check for suspicious occurrences of 'if(); {}'.

//---------------------------------------------------------------------------

void CheckOtherImpl::checkSuspiciousSemicolon()

{

if (!mSettings.certainty.isEnabled(Certainty::inconclusive) || !mSettings.severity.isEnabled(Severity::warning))

return;

const SymbolDatabase* const symbolDatabase = mTokenizer->getSymbolDatabase();

logChecker("CheckOther::checkSuspiciousSemicolon"); // warning,inconclusive

// Look for "if(); {}", "for(); {}" or "while(); {}"

for (const Scope &scope : symbolDatabase->scopeList) {

if (scope.type == ScopeType::eIf || scope.type == ScopeType::eElse || scope.type == ScopeType::eWhile || scope.type == ScopeType::eFor) {

// Ensure the semicolon is at the same line number as the if/for/while statement

// and the {..} block follows it without an extra empty line.

if (Token::simpleMatch(scope.bodyStart, "{ ; } {") &&

scope.bodyStart->previous()->linenr() == scope.bodyStart->tokAt(2)->linenr() &&

scope.bodyStart->linenr()+1 >= scope.bodyStart->tokAt(3)->linenr() &&

!scope.bodyStart->tokAt(3)->isExpandedMacro()) {

suspiciousSemicolonError(scope.classDef);

}

}

}

}

void CheckOtherImpl::suspiciousSemicolonError(const Token* tok)

{

reportError(tok, Severity::warning, "suspiciousSemicolon",

"Suspicious use of ; at the end of '" + (tok ? tok->str() : std::string()) + "' statement.", CWE398, Certainty::normal);

}

/** @brief would it make sense to use dynamic_cast instead of C style cast? */

static bool isDangerousTypeConversion(const Token* const tok)

{

const Token* from = tok->astOperand1();

if (!from)

return false;

if (!tok->valueType() || !from->valueType())

return false;

if (tok->valueType()->typeScope != nullptr &&

tok->valueType()->typeScope == from->valueType()->typeScope)

return false;

if (tok->valueType()->type == from->valueType()->type &&

tok->valueType()->isPrimitive())

return false;

// cast from derived object to base object is safe..

if (tok->valueType()->typeScope && from->valueType()->typeScope) {

const Type* fromType = from->valueType()->typeScope->definedType;

const Type* toType = tok->valueType()->typeScope->definedType;

if (fromType && toType && fromType->isDerivedFrom(toType->name()))

return false;

}

const bool refcast = (tok->valueType()->reference != Reference::None);

if (!refcast && tok->valueType()->pointer == 0)

return false;

if (!refcast && from->valueType()->pointer == 0)

return false;

if (tok->valueType()->type == ValueType::Type::VOID || from->valueType()->type == ValueType::Type::VOID)

return false;

if (tok->valueType()->pointer == 0 && tok->valueType()->isIntegral())

// ok: (uintptr_t)ptr;

return false;

if (from->valueType()->pointer == 0 && from->valueType()->isIntegral())

// ok: (int *)addr;

return false;

return true;

}

//---------------------------------------------------------------------------

// For C++ code, warn if C-style casts are used on pointer types

//---------------------------------------------------------------------------

void CheckOtherImpl::warningOldStylePointerCast()

{

// Only valid on C++ code

if (!mTokenizer->isCPP())

return;

if (!mSettings.severity.isEnabled(Severity::style) && !mSettings.isPremiumEnabled("cstyleCast"))

return;

logChecker("CheckOther::warningOldStylePointerCast"); // style,c++

const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();

for (const Scope * scope : symbolDatabase->functionScopes) {

const Token* tok;

if (scope->function && scope->function->isConstructor())

tok = scope->classDef;

else

tok = scope->bodyStart;

for (; tok && tok != scope->bodyEnd; tok = tok->next()) {

// Old style pointer casting..

if (!tok->isCast() || tok->isBinaryOp())

continue;

if (isDangerousTypeConversion(tok))

continue;

const Token* const errtok = tok;

const Token* castTok = tok->next();

while (Token::Match(castTok, "const|volatile|class|struct|union|%type%|::")) {

castTok = castTok->next();

if (Token::simpleMatch(castTok, "<") && castTok->link())

castTok = castTok->link()->next();

}

if (castTok == tok->next())

continue;

bool isPtr = false, isRef = false;

while (Token::Match(castTok, "*|const|&")) {

if (castTok->str() == "*")

isPtr = true;

else if (castTok->str() == "&")

isRef = true;

castTok = castTok->next();

}

if ((!isPtr && !isRef) || !Token::Match(castTok, ") (| %name%|%bool%|%char%|%str%|&"))

continue;

if (Token::Match(tok->previous(), "%type%"))

continue;

// skip first "const" in "const Type* const"

while (Token::Match(tok->next(), "const|volatile|class|struct|union"))

tok = tok->next();

const Token* typeTok = tok->next();

// skip second "const" in "const Type* const"

if (tok->strAt(3) == "const")

tok = tok->next();

const Token *p = tok->tokAt(4);

if (p->hasKnownIntValue() && p->getKnownIntValue()==0) // Casting nullpointers is safe

continue;

if (typeTok->tokType() == Token::eType || typeTok->tokType() == Token::eName)

cstyleCastError(errtok, isPtr);

}

}

}

void CheckOtherImpl::cstyleCastError(const Token *tok, bool isPtr)

{

const std::string type = isPtr ? "pointer" : "reference";

reportError(tok, Severity::style, "cstyleCast",

"C-style " + type + " casting\n"

"C-style " + type + " casting detected. C++ offers four different kinds of casts as replacements: "

"static_cast, const_cast, dynamic_cast and reinterpret_cast. A C-style cast could evaluate to "

"any of those automatically, thus it is considered safer if the programmer explicitly states "

"which kind of cast is expected.", CWE398, Certainty::normal);

}

void CheckOtherImpl::warningDangerousTypeCast()

{

// Only valid on C++ code

if (!mTokenizer->isCPP())

return;

if (!mSettings.severity.isEnabled(Severity::warning) && !mSettings.isPremiumEnabled("dangerousTypeCast"))

return;

logChecker("CheckOther::warningDangerousTypeCast"); // warning,c++

const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();

for (const Scope * scope : symbolDatabase->functionScopes) {

const Token* tok;

if (scope->function && scope->function->isConstructor())

tok = scope->classDef;

else

tok = scope->bodyStart;

for (; tok && tok != scope->bodyEnd; tok = tok->next()) {

// Old style pointer casting..

if (!tok->isCast() || tok->isBinaryOp())

continue;

if (isDangerousTypeConversion(tok))

dangerousTypeCastError(tok, tok->valueType()->pointer > 0);

}

}

}

void CheckOtherImpl::dangerousTypeCastError(const Token *tok, bool isPtr)

{

//const std::string type = isPtr ? "pointer" : "reference";

(void)isPtr;

reportError(tok, Severity::warning, "dangerousTypeCast",

"Potentially invalid type conversion in old-style C cast, clarify/fix with C++ cast",

CWE398, Certainty::normal);

}

void CheckOtherImpl::warningIntToPointerCast()

{

if (!mSettings.severity.isEnabled(Severity::portability) && !mSettings.isPremiumEnabled("cstyleCast"))

return;

logChecker("CheckOther::warningIntToPointerCast"); // portability

for (const Token* tok = mTokenizer->tokens(); tok; tok = tok->next()) {

// pointer casting..

if (!tok->isCast())

continue;

const Token* from = tok->astOperand2() ? tok->astOperand2() : tok->astOperand1();

if (!from || !from->isNumber())

continue;

if (!tok->valueType() || tok->valueType()->pointer == 0)

continue;

if (!MathLib::isIntHex(from->str()) && from->hasKnownIntValue() && from->getKnownIntValue() != 0) {

std::string format;

if (MathLib::isDec(from->str()))

format = "decimal";

else if (MathLib::isOct(from->str()))

format = "octal";

else if (MathLib::isBin(from->str()))

format = "binary";

else

continue;

intToPointerCastError(tok, format);

}

}

}

void CheckOtherImpl::intToPointerCastError(const Token *tok, const std::string& format)

{

reportError(tok, Severity::portability, "intToPointerCast",

"Casting non-zero " + format + " integer literal to pointer.",

CWE398, Certainty::normal);

}

void CheckOtherImpl::suspiciousFloatingPointCast()

{

if (!mSettings.severity.isEnabled(Severity::style) && !mSettings.isPremiumEnabled("suspiciousFloatingPointCast"))

return;

logChecker("CheckOther::suspiciousFloatingPointCast"); // style

const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();

for (const Scope * scope : symbolDatabase->functionScopes) {

const Token* tok = scope->bodyStart;

if (scope->function && scope->function->isConstructor())

tok = scope->classDef;

for (; tok && tok != scope->bodyEnd; tok = tok->next()) {

if (!tok->isCast())

continue;

const ValueType* vt = tok->valueType();

if (!vt || vt->pointer || vt->reference != Reference::None || (vt->type != ValueType::FLOAT && vt->type != ValueType::DOUBLE))

continue;

using VTT = std::vector<ValueType::Type>;

const VTT sourceTypes = vt->type == ValueType::FLOAT ? VTT{ ValueType::DOUBLE, ValueType::LONGDOUBLE } : VTT{ ValueType::LONGDOUBLE };

const Token* source = tok->astOperand2() ? tok->astOperand2() : tok->astOperand1();

if (!source || !source->valueType() || std::find(sourceTypes.begin(), sourceTypes.end(), source->valueType()->type) == sourceTypes.end())

continue;

const Token* parent = tok->astParent();

if (!parent)

continue;

const ValueType* parentVt = parent->valueType();

if (!parentVt || parent->str() == "(") {

int argn{};

if (const Token* ftok = getTokenArgumentFunction(tok, argn)) {

if (ftok->function()) {

if (const Variable* argVar = ftok->function()->getArgumentVar(argn))

parentVt = argVar->valueType();

}

}

}

if (!parentVt || std::find(sourceTypes.begin(), sourceTypes.end(), parentVt->type) == sourceTypes.end())

continue;

suspiciousFloatingPointCastError(tok);

}

}

}

void CheckOtherImpl::suspiciousFloatingPointCastError(const Token* tok)

{

reportError(tok, Severity::style, "suspiciousFloatingPointCast",

"Floating-point cast causes loss of precision.\n"

"If this cast is not intentional, remove it to avoid loss of precision", CWE398, Certainty::normal);

}

//---------------------------------------------------------------------------

// float* f; double* d = (double*)f; <-- Pointer cast to a type with an incompatible binary data representation

//---------------------------------------------------------------------------

void CheckOtherImpl::invalidPointerCast()

{

if (!mSettings.severity.isEnabled(Severity::portability))

return;

logChecker("CheckOther::invalidPointerCast"); // portability

const bool printInconclusive = mSettings.certainty.isEnabled(Certainty::inconclusive);

const SymbolDatabase* const symbolDatabase = mTokenizer->getSymbolDatabase();

for (const Scope * scope : symbolDatabase->functionScopes) {

for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {

const Token* toTok = nullptr;

const Token* fromTok = nullptr;

// Find cast

if (Token::Match(tok, "( const|volatile| const|volatile| %type% %type%| const| * )")) {

toTok = tok;

fromTok = tok->astOperand1();

} else if (Token::simpleMatch(tok, "reinterpret_cast <") && tok->linkAt(1)) {

toTok = tok->linkAt(1)->next();

fromTok = toTok->astOperand2();

}

if (!fromTok)

continue;

const ValueType* fromType = fromTok->valueType();

const ValueType* toType = toTok->valueType();

if (!fromType || !toType || !fromType->pointer || !toType->pointer)

continue;

if (fromType->type != toType->type && fromType->type >= ValueType::Type::BOOL && toType->type >= ValueType::Type::BOOL && (toType->type != ValueType::Type::CHAR || printInconclusive)) {

if (toType->isIntegral() && fromType->isIntegral())

continue;

invalidPointerCastError(tok, fromType->str(), toType->str(), toType->type == ValueType::Type::CHAR, toType->isIntegral());

}

}

}

}

void CheckOtherImpl::invalidPointerCastError(const Token* tok, const std::string& from, const std::string& to, bool inconclusive, bool toIsInt)

{

if (toIsInt) { // If we cast something to int*, this can be useful to play with its binary data representation

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);

} else

reportError(tok, Severity::portability, "invalidPointerCast", "Casting between " + from + " and " + to + " which have an incompatible binary data representation.", CWE704, Certainty::normal);

}

//---------------------------------------------------------------------------

// Detect redundant assignments: x = 0; x = 4;

//---------------------------------------------------------------------------

void CheckOtherImpl::checkRedundantAssignment()

{

if (!mSettings.severity.isEnabled(Severity::style) &&

!mSettings.isPremiumEnabled("redundantAssignment") &&

!mSettings.isPremiumEnabled("redundantAssignInSwitch"))

return;

logChecker("CheckOther::checkRedundantAssignment"); // style

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() || tok->tokType() == Token::eIncDecOp) && 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, "%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;

bool inconclusive = false;

if (tok->isCpp() && tok->astOperand1()->valueType()) {

// If there is a custom assignment operator => this is inconclusive

if (tok->astOperand1()->valueType()->typeScope) {

const std::string op = "operator" + tok->str();

const std::list<Function>& fList = tok->astOperand1()->valueType()->typeScope->functionList;

inconclusive = std::any_of(fList.cbegin(), fList.cend(), [&](const Function& f) {

return f.name() == op;

});

}

// assigning a smart pointer has side effects

if (tok->astOperand1()->valueType()->type == ValueType::SMART_POINTER)

break;

}

if (inconclusive && !mSettings.certainty.isEnabled(Certainty::inconclusive))

continue;

FwdAnalysis fwdAnalysis(mSettings);

if (fwdAnalysis.hasOperand(tok->astOperand2(), tok->astOperand1()))

continue;

// Is there a redundant assignment?

const Token *start;

if (tok->isAssignmentOp())

start = tok->astOperand2();

else

start = tok->findExpressionStartEndTokens().second->next();

const Token * tokenToCheck = tok->astOperand1();

// Check if we are working with union

for (const Token* tempToken = tokenToCheck; Token::simpleMatch(tempToken, ".");) {

tempToken = tempToken->astOperand1();

if (tempToken && tempToken->variable() && tempToken->variable()->type() && tempToken->variable()->type()->isUnionType())

tokenToCheck = tempToken;

}

if (start->hasKnownSymbolicValue(tokenToCheck) && Token::simpleMatch(start->astParent(), "=") && !diag(tok)) {

const ValueFlow::Value* val = start->getKnownValue(ValueFlow::Value::ValueType::SYMBOLIC);

if (val->intvalue == 0) // no offset

redundantAssignmentSameValueError(tokenToCheck, val, tok->astOperand1()->expressionString());

}

// Get next assignment..

const Token *nextAssign = fwdAnalysis.reassign(tokenToCheck, start, scope->bodyEnd);

// extra check for union

if (nextAssign && tokenToCheck != tok->astOperand1()) {

nextAssign = fwdAnalysis.reassign(tok->astOperand1(), start, scope->bodyEnd);

// reading another member of the same union in the rhs is a use through aliasing

if (nextAssign && fwdAnalysis.hasOperand(nextAssign->astOperand2(), tokenToCheck))

nextAssign = nullptr;

}

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 {

diag(nextAssign);

redundantAssignmentError(tok, nextAssign, tok->astOperand1()->expressionString(), inconclusive);

}

}

}

}

}

void CheckOtherImpl::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 CheckOtherImpl::redundantAssignmentError(const Token *tok1, const Token* tok2, const std::string& var, bool inconclusive)

{

ErrorPath errorPath = { ErrorPathItem(tok1, var + " is assigned"), ErrorPathItem(tok2, var + " is overwritten") };

if (inconclusive)

reportError(std::move(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(std::move(errorPath), Severity::style, "redundantAssignment",

"$symbol:" + var + "\n"

"Variable '$symbol' is reassigned a value before the old one has been used.", CWE563, Certainty::normal);

}

void CheckOtherImpl::redundantInitializationError(const Token *tok1, const Token* tok2, const std::string& var, bool inconclusive)

{

ErrorPath errorPath = { ErrorPathItem(tok1, var + " is initialized"), ErrorPathItem(tok2, var + " is overwritten") };

reportError(std::move(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 CheckOtherImpl::redundantAssignmentInSwitchError(const Token *tok1, const Token* tok2, const std::string &var)

{

ErrorPath errorPath = { ErrorPathItem(tok1, "$symbol is assigned"), ErrorPathItem(tok2, "$symbol is overwritten") };

reportError(std::move(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);

}

void CheckOtherImpl::redundantAssignmentSameValueError(const Token *tok, const ValueFlow::Value* val, const std::string &var)

{

auto errorPath = val->errorPath;

errorPath.emplace_back(tok, "");

reportError(std::move(errorPath), Severity::style, "redundantAssignment",

"$symbol:" + var + "\n"

"Variable '$symbol' is assigned an expression that holds the same value.", 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)

{

return Token::Match(tok, "%name% (") || (tok->isKeyword() && Token::Match(tok, "break|continue|return|goto|throw"));

}

void CheckOtherImpl::redundantBitwiseOperationInSwitchError()

{

if (!mSettings.severity.isEnabled(Severity::warning))

return;

logChecker("CheckOther::redundantBitwiseOperationInSwitch"); // warning

const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();

// Find the beginning of a switch. E.g.:

// switch (var) { ...

for (const Scope &switchScope : symbolDatabase->scopeList) {

if (switchScope.type != ScopeType::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%")) {

std::string bitOp = tok2->strAt(1)[0] + tok2->strAt(2);

const auto i2 = utils::as_const(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()] = std::move(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()) {

std::string bitOp = tok2->strAt(3) + tok2->strAt(4);

const auto i2 = utils::as_const(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()] = std::move(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 CheckOtherImpl::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 CheckOtherImpl::checkSuspiciousCaseInSwitch()

{

if (!mSettings.certainty.isEnabled(Certainty::inconclusive) || !mSettings.severity.isEnabled(Severity::warning))

return;

logChecker("CheckOther::checkSuspiciousCaseInSwitch"); // warning,inconclusive

const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();

for (const Scope & scope : symbolDatabase->scopeList) {

if (scope.type != ScopeType::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 CheckOtherImpl::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);

}

void CheckOtherImpl::checkUnreachableSwitchCase()

{

if (!mSettings.severity.isEnabled(Severity::style))

return;

logChecker("CheckOther::checkUnreachableSwitchCase"); // style

const SymbolDatabase* symbolDatabase = mTokenizer->getSymbolDatabase();

for (const Scope& scope : symbolDatabase->scopeList) {

if (scope.type != ScopeType::eSwitch || !scope.bodyStart)

continue;

const Token* rpar = scope.bodyStart->previous();

if (!Token::simpleMatch(rpar, ")"))

continue;

const Token* lpar = rpar->link();

if (!lpar)

continue;

const Token* condition = lpar->astOperand2();

if (!condition)

continue;

const ValueFlow::Value* switchValue =

condition->getKnownValue(ValueFlow::Value::ValueType::INT);

if (!switchValue)

continue;

for (const Token* tok = scope.bodyStart->next();

tok && tok != scope.bodyEnd;

tok = tok->next()) {