/*

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

* Copyright (C) 2007-2016 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 "mathlib.h"

#include "symboldatabase.h"

#include "utils.h"

#include <stack>

#include <algorithm> // find_if()

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

// Register this check class (by creating a static instance of it)

namespace {

CheckOther instance;

}

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

// 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 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 CheckOther::checkCastIntToCharAndBack()

{

if (!_settings->isEnabled("warning"))

return;

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

const std::size_t functions = symbolDatabase->functionScopes.size();

for (std::size_t i = 0; i < functions; ++i) {

const Scope * scope = symbolDatabase->functionScopes[i];

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

for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) {

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

if (!tok->isName() || !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 (_tokenizer->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 (_tokenizer->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 CheckOther::checkCastIntToCharAndBackError(const Token *tok, const std::string &strFunctionName)

{

reportError(

tok,

Severity::warning,

"checkCastIntToCharAndBack",

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

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

" When "+ strFunctionName +"() returns EOF this value is truncated. Comparing the char "

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

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

"when the file contains a matching character."

);

}

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

// Clarify calculation precedence for ternary operators.

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

void CheckOther::clarifyCalculation()

{

if (!_settings->isEnabled("style"))

return;

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

const std::size_t functions = symbolDatabase->functionScopes.size();

for (std::size_t i = 0; i < functions; ++i) {

const Scope * scope = symbolDatabase->functionScopes[i];

for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; 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;

// 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 CheckOther::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 + "'.");

}

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

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

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

void CheckOther::clarifyStatement()

{

if (!_settings->isEnabled("warning"))

return;

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

const std::size_t functions = symbolDatabase->functionScopes.size();

for (std::size_t i = 0; i < functions; ++i) {

const Scope * scope = symbolDatabase->functionScopes[i];

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

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

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 CheckOther::clarifyStatementError(const Token *tok)

{

reportError(tok, Severity::warning, "clarifyStatement", "Ineffective statement similar to '*A++;'. 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)++;'?");

}

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

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

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

void CheckOther::checkSuspiciousSemicolon()

{

if (!_settings->inconclusive || !_settings->isEnabled("warning"))

return;

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

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

for (std::list<Scope>::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) {

if (i->type == Scope::eIf || i->type == Scope::eElse || i->type == Scope::eWhile || i->type == Scope::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(i->classStart, "{ ; } {") &&

i->classStart->previous()->linenr() == i->classStart->tokAt(2)->linenr()

&& i->classStart->linenr()+1 >= i->classStart->tokAt(3)->linenr()) {

SuspiciousSemicolonError(i->classDef);

}

}

}

}

void CheckOther::SuspiciousSemicolonError(const Token* tok)

{

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

"Suspicious use of ; at the end of '" + (tok ? tok->str() : std::string()) + "' statement.", 0U, true);

}

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

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

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

void CheckOther::warningOldStylePointerCast()

{

// Only valid on C++ code

if (!_settings->isEnabled("style") || !_tokenizer->isCPP())

return;

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

for (std::size_t i = 0; i < symbolDatabase->functionScopes.size(); ++i) {

const Scope * scope = symbolDatabase->functionScopes[i];

const Token* tok;

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

tok = scope->classDef;

else

tok = scope->classStart;

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

// Old style pointer casting..

if (!Token::Match(tok, "( const| %type% * const| ) (| %name%|%num%|%bool%|%char%|%str%"))

continue;

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

if (tok->strAt(1) == "const")

tok = tok->next();

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

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

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

tok = tok->next();

if (tok->strAt(4) == "0") // Casting nullpointers is safe

continue;

// Is "type" a class?

if (typeTok->type())

cstyleCastError(tok);

}

}

}

void CheckOther::cstyleCastError(const Token *tok)

{

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

"C-style pointer casting\n"

"C-style pointer 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. See also: https://www.securecoding.cert.org/confluence/display/cplusplus/EXP05-CPP.+Do+not+use+C-style+casts.");

}

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

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

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

static std::string analyzeType(const Token* tok)

{

if (tok->str() == "double") {

if (tok->isLong())

return "long double";

else

return "double";

}

if (tok->str() == "float")

return "float";

if (Token::Match(tok, "int|long|short|char|size_t"))

return "integer";

return "";

}

void CheckOther::invalidPointerCast()

{

if (!_settings->isEnabled("portability"))

return;

const bool printInconclusive = _settings->inconclusive;

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

const std::size_t functions = symbolDatabase->functionScopes.size();

for (std::size_t i = 0; i < functions; ++i) {

const Scope * scope = symbolDatabase->functionScopes[i];

for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) {

const Token* toTok = nullptr;

const Token* nextTok = nullptr;

// Find cast

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

toTok = tok->next();

nextTok = tok->link()->next();

if (nextTok && nextTok->str() == "(")

nextTok = nextTok->next();

} else if (Token::Match(tok, "reinterpret_cast < const| %type% %type%| const| * > (")) {

nextTok = tok->tokAt(5);

while (nextTok->str() != "(")

nextTok = nextTok->next();

nextTok = nextTok->next();

toTok = tok->tokAt(2);

}

if (!nextTok)

continue;

if (toTok && toTok->str() == "const")

toTok = toTok->next();

if (!toTok || !toTok->isStandardType())

continue;

// Find casted variable

const Variable *var = nullptr;

bool allocation = false;

bool ref = false;

if (_tokenizer->isCPP() && Token::Match(nextTok, "new %type%"))

allocation = true;

else if (Token::Match(nextTok, "%var% !!["))

var = nextTok->variable();

else if (Token::Match(nextTok, "& %var%") && !Token::Match(nextTok->tokAt(2), "(|[")) {

var = nextTok->next()->variable();

ref = true;

}

const Token* fromTok = nullptr;

if (allocation) {

fromTok = nextTok->next();

} else {

if (!var || (!ref && !var->isPointer() && !var->isArray()) || (ref && (var->isPointer() || var->isArray())))

continue;

fromTok = var->typeStartToken();

}

while (Token::Match(fromTok, "static|const"))

fromTok = fromTok->next();

if (!fromTok->isStandardType())

continue;

std::string fromType = analyzeType(fromTok);

std::string toType = analyzeType(toTok);

if (fromType != toType && !fromType.empty() && !toType.empty() && (toTok->str() != "char" || printInconclusive))

invalidPointerCastError(tok, fromType, toType, toTok->str() == "char");

}

}

}

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

{

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

if (!inconclusive)

reportError(tok, Severity::portability, "invalidPointerCast", "Casting from " + from + "* to integer* is not portable due to different binary data representations on different platforms.");

else

reportError(tok, Severity::portability, "invalidPointerCast", "Casting from " + from + "* to char* is not portable due to different binary data representations on different platforms.", 0U, true);

} else

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

}

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

// This check detects errors on POSIX systems, when a pipe command called

// with a wrong dimensioned file descriptor array. The pipe command requires

// exactly an integer array of dimension two as parameter.

//

// References:

// - http://linux.die.net/man/2/pipe

// - ticket #3521

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

void CheckOther::checkPipeParameterSize()

{

if (!_settings->standards.posix)

return;

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

const std::size_t functions = symbolDatabase->functionScopes.size();

for (std::size_t i = 0; i < functions; ++i) {

const Scope * scope = symbolDatabase->functionScopes[i];

for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) {

if (Token::Match(tok, "pipe ( %var% )") ||

Token::Match(tok, "pipe2 ( %var% ,")) {

const Token * const varTok = tok->tokAt(2);

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

MathLib::bigint dim;

if (var && var->isArray() && !var->isArgument() && ((dim=var->dimension(0U)) < 2)) {

const std::string strDim = MathLib::toString(dim);

checkPipeParameterSizeError(varTok,varTok->str(), strDim);

}

}

}

}

}

void CheckOther::checkPipeParameterSizeError(const Token *tok, const std::string &strVarName, const std::string &strDim)

{

reportError(tok, Severity::error,

"wrongPipeParameterSize", "Buffer '" + strVarName + "' must have size of 2 integers if used as parameter of pipe().\n"

"The pipe()/pipe2() system command takes an argument, which is an array of exactly two integers.\n"

"The variable '" + strVarName + "' is an array of size " + strDim + ", which does not match.");

}

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

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

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

static bool nonLocal(const Variable* var)

{

return !var || (!var->isLocal() && !var->isArgument()) || var->isStatic() || var->isReference();

}

static void eraseNotLocalArg(std::map<unsigned int, const Token*>& container, const SymbolDatabase* symbolDatabase)

{

for (std::map<unsigned int, const Token*>::iterator i = container.begin(); i != container.end();) {

const Variable* var = symbolDatabase->getVariableFromVarId(i->first);

if (!var || nonLocal(var)) {

container.erase(i++);

} else

++i;

}

}

static void eraseMemberAssignments(const unsigned int varId, const std::map<unsigned int, std::set<unsigned int> > &membervars, std::map<unsigned int, const Token*> &varAssignments)

{

const std::map<unsigned int, std::set<unsigned int> >::const_iterator it = membervars.find(varId);

if (it != membervars.end()) {

const std::set<unsigned int>& v = it->second;

for (std::set<unsigned int>::const_iterator vit = v.begin(); vit != v.end(); ++vit) {

varAssignments.erase(*vit);

if (*vit != varId)

eraseMemberAssignments(*vit, membervars, varAssignments);

}

}

}

static bool checkExceptionHandling(const Token* tok)

{

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

const Scope* upperScope = tok->scope();

if (var && upperScope == var->scope())

return true;

while (upperScope && upperScope->type != Scope::eTry && upperScope->type != Scope::eLambda && (!var || upperScope->nestedIn != var->scope()) && upperScope->isExecutable()) {

upperScope = upperScope->nestedIn;

}

if (var && upperScope && upperScope->type == Scope::eTry) {

// Check all exception han

const Token* tok2 = upperScope->classEnd;

while (Token::simpleMatch(tok2, "} catch (")) {

tok2 = tok2->linkAt(2)->next();

if (Token::findmatch(tok2, "%varid%", tok2->link(), var->declarationId()))

return false;

tok2 = tok2->link();

}

}

return true;

}

void CheckOther::checkRedundantAssignment()

{

const bool printPerformance = _settings->isEnabled("performance");

const bool printWarning = _settings->isEnabled("warning");

if (!printWarning && !printPerformance)

return;

const bool printInconclusive = _settings->inconclusive;

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

for (std::list<Scope>::const_iterator scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {

if (!scope->isExecutable())

continue;

std::map<unsigned int, const Token*> varAssignments;

std::map<unsigned int, const Token*> memAssignments;

std::map<unsigned int, std::set<unsigned int> > membervars;

std::set<unsigned int> initialized;

const Token* writtenArgumentsEnd = nullptr;

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

if (tok == writtenArgumentsEnd)

writtenArgumentsEnd = nullptr;

if (tok->str() == "?" && tok->astOperand2()) {

tok = Token::findmatch(tok->astOperand2(), ";|}");

if (!tok)

break;

varAssignments.clear();

memAssignments.clear();

} else if (tok->str() == "{" && tok->strAt(-1) != "{" && tok->strAt(-1) != "=" && tok->strAt(-4) != "case" && tok->strAt(-3) != "default") { // conditional or non-executable inner scope: Skip it and reset status

tok = tok->link();

varAssignments.clear();

memAssignments.clear();

} else if (Token::Match(tok, "for|if|while (")) {

tok = tok->linkAt(1);

} else if (Token::Match(tok, "break|return|continue|throw|goto|asm")) {

varAssignments.clear();

memAssignments.clear();

} else if (tok->tokType() == Token::eVariable && !Token::Match(tok, "%name% (")) {

// Set initialization flag

if (!Token::Match(tok, "%var% ["))

initialized.insert(tok->varId());

else {

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

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

tok2 = tok2->link()->next();

if (tok2 && tok2->str() != ";")

initialized.insert(tok->varId());

}

const Token *startToken = tok;

while (Token::Match(startToken, "%name%|::|.")) {

startToken = startToken->previous();

if (Token::Match(startToken, "%name% . %var%"))

membervars[startToken->varId()].insert(startToken->tokAt(2)->varId());

}

std::map<unsigned int, const Token*>::iterator it = varAssignments.find(tok->varId());

if (Token::simpleMatch(tok->next(), "=") && Token::Match(startToken, "[;{}]")) { // Assignment

if (it != varAssignments.end()) {

bool error = true; // Ensure that variable is not used on right side

for (const Token* tok2 = tok->tokAt(2); tok2; tok2 = tok2->next()) {

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

break;

else if (tok2->varId() == tok->varId()) {

error = false;

break;

} else if (Token::Match(tok2, "%name% (") && nonLocal(tok->variable())) { // Called function might use the variable

const Function* const func = tok2->function();

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

if (!var || var->isGlobal() || var->isReference() || ((!func || func->nestedIn) && tok2->strAt(-1) != ".")) {// Global variable, or member function

error = false;

break;

}

}

}

if (error) {

if (printWarning && scope->type == Scope::eSwitch && Token::findmatch(it->second, "default|case", tok))

redundantAssignmentInSwitchError(it->second, tok, tok->str());

else if (printPerformance) {

// See #7133

const bool nonlocal = it->second->variable() && nonLocal(it->second->variable());

if (printInconclusive || !nonlocal) // see #5089 - report inconclusive only when requested

if (_tokenizer->isC() || checkExceptionHandling(tok)) // see #6555 to see how exception handling might have an impact

redundantAssignmentError(it->second, tok, tok->str(), nonlocal); // Inconclusive for non-local variables

}

}

it->second = tok;

}

if (!Token::simpleMatch(tok->tokAt(2), "0 ;") || (tok->variable() && tok->variable()->nameToken() != tok->tokAt(-2)))

varAssignments[tok->varId()] = tok;

memAssignments.erase(tok->varId());

eraseMemberAssignments(tok->varId(), membervars, varAssignments);

} else if ((tok->next() && tok->next()->tokType() == Token::eIncDecOp) || (tok->previous()->tokType() == Token::eIncDecOp && tok->strAt(1) == ";")) { // Variable incremented/decremented; Prefix-Increment is only suspicious, if its return value is unused

varAssignments[tok->varId()] = tok;

memAssignments.erase(tok->varId());

eraseMemberAssignments(tok->varId(), membervars, varAssignments);

} else if (!Token::simpleMatch(tok->tokAt(-2), "sizeof (")) { // Other usage of variable

if (it != varAssignments.end())

varAssignments.erase(it);

if (!writtenArgumentsEnd) // Indicates that we are in the first argument of strcpy/memcpy/... function

memAssignments.erase(tok->varId());

}

} else if (Token::Match(tok, "%name% (") && _settings->library.functionpure.find(tok->str()) == _settings->library.functionpure.end()) { // Function call. Global variables might be used. Reset their status

const bool memfunc = Token::Match(tok, "memcpy|memmove|memset|strcpy|strncpy|sprintf|snprintf|strcat|strncat|wcscpy|wcsncpy|swprintf|wcscat|wcsncat");

if (tok->varId()) // operator() or function pointer

varAssignments.erase(tok->varId());

if (memfunc && tok->strAt(-1) != "(" && tok->strAt(-1) != "=") {

const Token* param1 = tok->tokAt(2);

writtenArgumentsEnd = param1->next();

if (param1->varId() && param1->strAt(1) == "," && !Token::Match(tok, "strcat|strncat|wcscat|wcsncat")) {

if (tok->str() == "memset" && initialized.find(param1->varId()) == initialized.end() && param1->variable() && param1->variable()->isLocal() && param1->variable()->isArray())

initialized.insert(param1->varId());

else {

const std::map<unsigned int, const Token*>::const_iterator it = memAssignments.find(param1->varId());

if (it == memAssignments.end())

memAssignments[param1->varId()] = tok;

else {

if (printWarning && scope->type == Scope::eSwitch && Token::findmatch(it->second, "default|case", tok))

redundantCopyInSwitchError(it->second, tok, param1->str());

else if (printPerformance)

redundantCopyError(it->second, tok, param1->str());

}

}

}

} else if (scope->type == Scope::eSwitch) { // Avoid false positives if noreturn function is called in switch

const Function* const func = tok->function();

if (!func || !func->hasBody()) {

varAssignments.clear();

memAssignments.clear();

continue;

}

const Token* funcEnd = func->functionScope->classEnd;

bool noreturn;

if (!_tokenizer->IsScopeNoReturn(funcEnd, &noreturn) && !noreturn) {

eraseNotLocalArg(varAssignments, symbolDatabase);

eraseNotLocalArg(memAssignments, symbolDatabase);

} else {

varAssignments.clear();

memAssignments.clear();

}

} else { // Noreturn functions outside switch don't cause problems

eraseNotLocalArg(varAssignments, symbolDatabase);

eraseNotLocalArg(memAssignments, symbolDatabase);

}

}

}

}

}

void CheckOther::redundantCopyError(const Token *tok1, const Token* tok2, const std::string& var)

{

const std::list<const Token *> callstack = make_container< std::list<const Token *> >() << tok1 << tok2;

reportError(callstack, Severity::performance, "redundantCopy",

"Buffer '" + var + "' is being written before its old content has been used.");

}

void CheckOther::redundantCopyInSwitchError(const Token *tok1, const Token* tok2, const std::string &var)

{

const std::list<const Token *> callstack = make_container< std::list<const Token *> >() << tok1 << tok2;

reportError(callstack, Severity::warning, "redundantCopyInSwitch",

"Buffer '" + var + "' is being written before its old content has been used. 'break;' missing?");

}

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

{

const std::list<const Token *> callstack = make_container< std::list<const Token *> >() << tok1 << tok2;

if (inconclusive)

reportError(callstack, Severity::performance, "redundantAssignment",

"Variable '" + var + "' is reassigned a value before the old one has been used if variable is no semaphore variable.\n"

"Variable '" + var + "' 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.", 0U, true);

else

reportError(callstack, Severity::performance, "redundantAssignment",

"Variable '" + var + "' is reassigned a value before the old one has been used.");

}

void CheckOther::redundantAssignmentInSwitchError(const Token *tok1, const Token* tok2, const std::string &var)

{

const std::list<const Token *> callstack = make_container< std::list<const Token *> >() << tok1 << tok2;

reportError(callstack, Severity::warning, "redundantAssignInSwitch",

"Variable '" + var + "' is reassigned a value before the old one has been used. 'break;' missing?");

}

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

// 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 (!_settings->isEnabled("warning"))

return;

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

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

// switch (var) { ...

for (std::list<Scope>::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) {

if (i->type != Scope::eSwitch || !i->classStart)

continue;

// Check the contents of the switch statement

std::map<unsigned int, const Token*> varsWithBitsSet;

std::map<unsigned int, std::string> bitOperations;

for (const Token *tok2 = i->classStart->next(); tok2 != i->classEnd; 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);

std::map<unsigned 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()) {

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

std::map<unsigned 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::warning,

"redundantBitwiseOperationInSwitch", "Redundant bitwise operation on '" + varname + "' in 'switch' statement. 'break;' missing?");

}

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

// Detect fall through cases (experimental).

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

void CheckOther::checkSwitchCaseFallThrough()

{

if (!(_settings->isEnabled("style") && _settings->experimental))

return;

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

for (std::list<Scope>::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) {

if (i->type != Scope::eSwitch || !i->classStart) // Find the beginning of a switch

continue;

// Check the contents of the switch statement

std::stack<std::pair<Token *, bool> > ifnest;

bool justbreak = true;

bool firstcase = true;

for (const Token *tok2 = i->classStart; tok2 != i->classEnd; tok2 = tok2->next()) {

if (Token::simpleMatch(tok2, "if (")) {

tok2 = tok2->next()->link()->next();

ifnest.push(std::make_pair(tok2->link(), false));

justbreak = false;

} else if (Token::simpleMatch(tok2, "while (")) {

tok2 = tok2->next()->link()->next();

if (tok2->link()) // skip over "do { } while ( ) ;" case

tok2 = tok2->link();

justbreak = false;

} else if (Token::simpleMatch(tok2, "do {")) {

tok2 = tok2->next()->link();

justbreak = false;

} else if (Token::simpleMatch(tok2, "for (")) {

tok2 = tok2->next()->link()->next()->link();

justbreak = false;

} else if (Token::simpleMatch(tok2, "switch (")) {

// skip over nested switch, we'll come to that soon

tok2 = tok2->next()->link()->next()->link();

} else if (Token::Match(tok2, "break|continue|return|exit|goto|throw")) {

justbreak = true;

tok2 = Token::findsimplematch(tok2, ";");

} else if (Token::Match(tok2, "case|default")) {

if (!justbreak && !firstcase) {

switchCaseFallThrough(tok2);

}

tok2 = Token::findsimplematch(tok2, ":");

justbreak = true;

firstcase = false;

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

if (!ifnest.empty() && tok2 == ifnest.top().first) {

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

tok2 = tok2->tokAt(2);

ifnest.pop();

ifnest.push(std::make_pair(tok2->link(), justbreak));

justbreak = false;

} else {

justbreak &= ifnest.top().second;

ifnest.pop();

}

}

} else if (tok2->str() != ";") {

justbreak = false;

}

}

}

}

void CheckOther::switchCaseFallThrough(const Token *tok)

{

reportError(tok, Severity::style,

"switchCaseFallThrough", "Switch falls through case without comment. 'break;' missing?");

}

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

// Check for statements like case A||B: in switch()

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

void CheckOther::checkSuspiciousCaseInSwitch()

{

if (!_settings->inconclusive || !_settings->isEnabled("warning"))

return;

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

for (std::list<Scope>::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) {

if (i->type != Scope::eSwitch)

continue;

for (const Token* tok = i->classStart->next(); tok != i->classEnd; 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?", 0U, true);

}

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

// if (x == 1)

// x == 0; // <- suspicious equality comparison.

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

void CheckOther::checkSuspiciousEqualityComparison()

{

if (!_settings->isEnabled("warning") || !_settings->inconclusive)

return;

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

const std::size_t functions = symbolDatabase->functionScopes.size();

for (std::size_t i = 0; i < functions; ++i) {

const Scope * scope = symbolDatabase->functionScopes[i];

for (const Token* tok = scope->classStart; tok != scope->classEnd; tok = tok->next()) {

if (Token::simpleMatch(tok, "for (")) {

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

const Token* const closeParen = tok->linkAt(1);

// Search for any suspicious equality comparison in the initialization

// or increment-decrement parts of the for() loop.

// For example:

// for (i == 2; i < 10; i++)

// or

// for (i = 0; i < 10; i == a)

if (Token::Match(openParen->next(), "%name% =="))

suspiciousEqualityComparisonError(openParen->tokAt(2));

if (closeParen->strAt(-2) == "==")

suspiciousEqualityComparisonError(closeParen->tokAt(-2));

// Skip over for() loop conditions because "for (;running==1;)"

// is a bit strange, but not necessarily incorrect.

tok = closeParen;

} else if (Token::Match(tok, "[;{}] *| %name% == %any% ;")) {

// Exclude compound statements surrounded by parentheses, such as

// printf("%i\n", ({x==0;}));

// because they may appear as an expression in GNU C/C++.

// See http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html

const Token* afterStatement = tok->strAt(1) == "*" ? tok->tokAt(6) : tok->tokAt(5);

if (!Token::simpleMatch(afterStatement, "} )"))

suspiciousEqualityComparisonError(tok->next());

}

}

}

}

void CheckOther::suspiciousEqualityComparisonError(const Token* tok)

{

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

"Found suspicious equality comparison. Did you intend to assign a value instead?", 0U, true);

}

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

// 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 (!_settings->isEnabled("style"))

return;

const bool printInconclusive = _settings->inconclusive;

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

const std::size_t functions = symbolDatabase->functionScopes.size();

for (std::size_t i = 0; i < functions; ++i) {

const Scope * scope = symbolDatabase->functionScopes[i];

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

const Token* secondBreak = 0;

const Token* labelName = 0;

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")) {