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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2015 Daniel Marjamäki and 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 "checkstl.h"
#include "symboldatabase.h"
#include "checknullpointer.h"
#include <sstream>
// Register this check class (by creating a static instance of it)
namespace {
CheckStl instance;
}
// Error message for bad iterator usage..
void CheckStl::invalidIteratorError(const Token *tok, const std::string &iteratorName)
{
reportError(tok, Severity::error, "invalidIterator1", "Invalid iterator: " + iteratorName);
}
void CheckStl::iteratorsError(const Token *tok, const std::string &container1, const std::string &container2)
{
reportError(tok, Severity::error, "iterators", "Same iterator is used with different containers '" + container1 + "' and '" + container2 + "'.");
}
// Error message used when dereferencing an iterator that has been erased..
void CheckStl::dereferenceErasedError(const Token *erased, const Token* deref, const std::string &itername)
{
if (erased) {
std::list<const Token*> callstack;
callstack.push_back(deref);
callstack.push_back(erased);
reportError(callstack, Severity::error, "eraseDereference",
"Iterator '" + itername + "' used after element has been erased.\n"
"The iterator '" + itername + "' is invalid after the element it pointed to has been erased. "
"Dereferencing or comparing it with another iterator is invalid operation.");
} else {
reportError(deref, Severity::error, "eraseDereference",
"Invalid iterator '" + itername + "' used.\n"
"The iterator '" + itername + "' is invalid before being assigned. "
"Dereferencing or comparing it with another iterator is invalid operation.");
}
}
static const Token *skipMembers(const Token *tok)
{
while (Token::Match(tok, "%name% ."))
tok = tok->tokAt(2);
return tok;
}
void CheckStl::iterators()
{
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
// Using same iterator against different containers.
// for (it = foo.begin(); it != bar.end(); ++it)
for (unsigned int iteratorId = 1; iteratorId < symbolDatabase->getVariableListSize(); iteratorId++) {
const Variable* var = symbolDatabase->getVariableFromVarId(iteratorId);
// Check that its an iterator
if (!var || !var->isLocal() || !Token::Match(var->typeEndToken(), "iterator|const_iterator|reverse_iterator|const_reverse_iterator|auto"))
continue;
if (var->typeEndToken()->str() == "auto" && !Token::Match(var->typeEndToken(), "auto %name% ; %name% = %name% . begin|end ( )"))
continue;
if (var->type()) { // If it is defined, ensure that it is defined like an iterator
// look for operator* and operator++
const Function* end = var->type()->getFunction("operator*");
const Function* incOperator = var->type()->getFunction("operator++");
if (!end || end->argCount() > 0 || !incOperator)
continue;
}
// the validIterator flag says if the iterator has a valid value or not
bool validIterator = Token::Match(var->nameToken()->next(), "[(=]");
const Scope* invalidationScope = 0;
// The container this iterator can be used with
const Variable* container = 0;
const Scope* containerAssignScope = 0;
// When "validatingToken" is reached the validIterator is set to true
const Token* validatingToken = 0;
const Token* eraseToken = 0;
// Scan through the rest of the code and see if the iterator is
// used against other containers.
for (const Token *tok2 = var->nameToken(); tok2 && tok2 != var->scope()->classEnd; tok2 = tok2->next()) {
if (invalidationScope && tok2 == invalidationScope->classEnd)
validIterator = true; // Assume that the iterator becomes valid again
if (containerAssignScope && tok2 == containerAssignScope->classEnd)
container = 0; // We don't know which containers might be used with the iterator
if (tok2 == validatingToken)
validIterator = true;
// Is iterator compared against different container?
if (Token::Match(tok2, "%varid% !=|== %name% . end|rend|cend|crend ( )", iteratorId) && container && tok2->tokAt(2)->varId() != container->declarationId()) {
iteratorsError(tok2, container->name(), tok2->strAt(2));
tok2 = tok2->tokAt(6);
}
// Is the iterator used in a insert/erase operation?
else if (Token::Match(tok2, "%name% . insert|erase ( *| %varid% )|,", iteratorId)) {
const Token* itTok = tok2->tokAt(4);
if (itTok->str() == "*") {
if (tok2->strAt(2) == "insert")
continue;
itTok = itTok->next();
}
// It is bad to insert/erase an invalid iterator
if (!validIterator)
invalidIteratorError(tok2, itTok->str());
// If insert/erase is used on different container then
// report an error
if (container && tok2->varId() != container->declarationId()) {
// skip error message if container is a set..
const Variable *variableInfo = tok2->variable();
const Token *decltok = variableInfo ? variableInfo->typeStartToken() : nullptr;
if (Token::simpleMatch(decltok, "std :: set"))
continue; // No warning
// skip error message if the iterator is erased/inserted by value
if (itTok->previous()->str() == "*")
continue;
// Show error message, mismatching iterator is used.
iteratorsError(tok2, container->name(), tok2->str());
}
// invalidate the iterator if it is erased
else if (tok2->strAt(2) == "erase" && (tok2->strAt(4) != "*" || (container && tok2->varId() == container->declarationId()))) {
validIterator = false;
eraseToken = tok2;
invalidationScope = tok2->scope();
}
// skip the operation
tok2 = itTok->next();
}
// it = foo.erase(..
// taking the result of an erase is ok
else if (Token::Match(tok2, "%varid% = %name% .", iteratorId) &&
Token::simpleMatch(skipMembers(tok2->tokAt(2)), "erase (")) {
// the returned iterator is valid
validatingToken = tok2->linkAt(5);
tok2 = tok2->tokAt(5);
}
// Reassign the iterator
else if (Token::Match(tok2, "%varid% = %name% . begin|rbegin|cbegin|crbegin|find (", iteratorId)) {
validatingToken = tok2->linkAt(5);
container = tok2->tokAt(2)->variable();
containerAssignScope = tok2->scope();
// skip ahead
tok2 = tok2->tokAt(5);
}
// Reassign the iterator
else if (Token::Match(tok2, "%varid% = %any%", iteratorId)) {
// Assume that the iterator becomes valid.
// TODO: add checking that checks if the iterator becomes valid or not
validatingToken = Token::findmatch(tok2->tokAt(2), "[;)]");
// skip ahead
tok2 = tok2->tokAt(2);
}
// Passing iterator to function. Iterator might be initialized
else if (Token::Match(tok2, "%varid% ,|)", iteratorId)) {
validIterator = true;
}
// Dereferencing invalid iterator?
else if (!validIterator && Token::Match(tok2, "* %varid%", iteratorId)) {
dereferenceErasedError(eraseToken, tok2, tok2->strAt(1));
tok2 = tok2->next();
} else if (!validIterator && Token::Match(tok2, "%varid% . %name%", iteratorId)) {
dereferenceErasedError(eraseToken, tok2, tok2->str());
tok2 = tok2->tokAt(2);
}
// bailout handling. Assume that the iterator becomes valid if we see return/break.
// TODO: better handling
else if (Token::Match(tok2, "return|break")) {
validatingToken = Token::findsimplematch(tok2->next(), ";");
}
// bailout handling. Assume that the iterator becomes valid if we see else.
// TODO: better handling
else if (tok2 && tok2->str() == "else") {
validIterator = true;
}
}
}
}
// Error message for bad iterator usage..
void CheckStl::mismatchingContainersError(const Token *tok)
{
reportError(tok, Severity::error, "mismatchingContainers", "Iterators of different containers are used together.");
}
namespace {
const std::set<std::string> algorithm2 = make_container< std::set<std::string> >() // func(begin1, end1
<< "adjacent_find" << "all_of" << "any_of" << "binary_search" << "copy" << "copy_if" << "count" << "count_if" << "equal" << "equal_range"
<< "find" << "find_if" << "find_if_not" << "for_each" << "generate" << "is_heap" << "is_heap_until" << "is_partitioned"
<< "is_permutation" << "is_sorted" << "is_sorted_until" << "lower_bound" << "make_heap" << "max_element" << "minmax_element"
<< "min_element" << "mismatch" << "move" << "move_backward" << "next_permutation" << "none_of" << "partition" << "partition_copy"
<< "partition_point" << "pop_heap" << "prev_permutation" << "push_heap" << "random_shuffle" << "remove" << "remove_copy"
<< "remove_copy_if" << "remove_if" << "replace" << "replace_copy" << "replace_copy_if" << "replace_if" << "reverse" << "reverse_copy"
<< "search_n" << "shuffle" << "sort" << "sort_heap" << "stable_partition" << "stable_sort" << "swap_ranges" << "transform" << "unique"
<< "unique_copy" << "upper_bound" << "string" << "wstring" << "u16string" << "u32string";
const std::set<std::string> algorithm22 = make_container< std::set<std::string> >() // func(begin1 << end1 << begin2 << end2
<< "find_end" << "find_first_of" << "includes" << "lexicographical_compare" << "merge" << "partial_sort_copy"
<< "search" << "set_difference" << "set_intersection" << "set_symmetric_difference" << "set_union";
const std::set<std::string> algorithm1x1 = make_container< std::set<std::string> >() // func(begin1 << x << end1
<< "inplace_merge" << "nth_element" << "partial_sort" << "rotate" << "rotate_copy";
static const std::string iteratorBeginFuncPattern = "begin|cbegin|rbegin|crbegin";
static const std::string iteratorEndFuncPattern = "end|cend|rend|crend";
static const std::string pattern1x1_1 = "%name% . " + iteratorBeginFuncPattern + " ( ) , ";
static const std::string pattern1x1_2 = "%name% . " + iteratorEndFuncPattern + " ( ) ,|)";
static const std::string pattern2 = pattern1x1_1 + pattern1x1_2;
}
void CheckStl::mismatchingContainers()
{
// Check if different containers are used in various calls of standard functions
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
const std::size_t functions = symbolDatabase->functionScopes.size();
for (std::size_t ii = 0; ii < functions; ++ii) {
const Scope * scope = symbolDatabase->functionScopes[ii];
for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) {
if (!Token::Match(tok, "std :: %type% ( !!)"))
continue;
const Token* arg1 = tok->tokAt(4);
// TODO: If iterator variables are used instead then there are false negatives.
if (Token::Match(arg1, pattern2.c_str()) && algorithm2.find(tok->strAt(2)) != algorithm2.end()) {
if (arg1->str() != arg1->strAt(6)) {
mismatchingContainersError(arg1);
}
} else if (algorithm22.find(tok->strAt(2)) != algorithm22.end()) {
if (Token::Match(arg1, pattern2.c_str()) && arg1->str() != arg1->strAt(6))
mismatchingContainersError(arg1);
// Find third parameter
const Token* arg3 = arg1;
for (unsigned int i = 0; i < 2 && arg3; i++)
arg3 = arg3->nextArgument();
if (Token::Match(arg3, pattern2.c_str()) && arg3->str() != arg3->strAt(6))
mismatchingContainersError(arg3);
} else if (Token::Match(arg1, pattern1x1_1.c_str()) && algorithm1x1.find(tok->strAt(2)) != algorithm1x1.end()) {
// Find third parameter
const Token *arg3 = arg1->tokAt(6)->nextArgument();
if (Token::Match(arg3, pattern1x1_2.c_str())) {
if (arg1->str() != arg3->str()) {
mismatchingContainersError(arg1);
}
}
}
tok = arg1->linkAt(-1);
}
}
for (unsigned int varid = 0; varid < symbolDatabase->getVariableListSize(); varid++) {
const Variable* var = symbolDatabase->getVariableFromVarId(varid);
if (var && var->isStlStringType() && Token::Match(var->nameToken(), "%var% (") && Token::Match(var->nameToken()->tokAt(2), pattern2.c_str())) {
if (var->nameToken()->strAt(2) != var->nameToken()->strAt(8)) {
mismatchingContainersError(var->nameToken());
}
}
}
}
void CheckStl::stlOutOfBounds()
{
const SymbolDatabase* const symbolDatabase = _tokenizer->getSymbolDatabase();
// Scan through all scopes..
for (std::list<Scope>::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) {
const Token* tok = i->classDef;
// only interested in conditions
if ((i->type != Scope::eFor && i->type != Scope::eWhile && i->type != Scope::eIf && i->type != Scope::eDo) || !tok)
continue;
if (i->type == Scope::eFor)
tok = Token::findsimplematch(tok->tokAt(2), ";");
else if (i->type == Scope::eDo) {
tok = tok->linkAt(1)->tokAt(2);
} else
tok = tok->next();
if (!tok)
continue;
tok = tok->next();
// check if the for loop condition is wrong
if (Token::Match(tok, "%var% <= %var% . %name% ( ) ;|)|%oror%")) {
// Is it a vector?
const Variable *var = tok->tokAt(2)->variable();
if (!var)
continue;
const Library::Container* container = _settings->library.detectContainer(var->typeStartToken());
if (!container)
continue;
if (container->getYield(tok->strAt(4)) != Library::Container::SIZE)
continue;
// variable id for loop variable.
const unsigned int numId = tok->varId();
// variable id for the container variable
const unsigned int declarationId = var->declarationId();
for (const Token *tok3 = i->classStart; tok3 && tok3 != i->classEnd; tok3 = tok3->next()) {
if (tok3->varId() == declarationId) {
tok3 = tok3->next();
if (Token::Match(tok3, ". %name% ( )")) {
if (container->getYield(tok3->strAt(1)) == Library::Container::SIZE)
break;
} else if (container->arrayLike_indexOp && Token::Match(tok3, "[ %varid% ]", numId))
stlOutOfBoundsError(tok3, tok3->strAt(1), var->name(), false);
else if (Token::Match(tok3, ". %name% ( %varid% )", numId)) {
Library::Container::Yield yield = container->getYield(tok3->strAt(1));
if (yield == Library::Container::AT_INDEX)
stlOutOfBoundsError(tok3, tok3->strAt(3), var->name(), true);
}
}
}
continue;
}
}
}
void CheckStl::stlOutOfBoundsError(const Token *tok, const std::string &num, const std::string &var, bool at)
{
if (at)
reportError(tok, Severity::error, "stlOutOfBounds", "When " + num + "==" + var + ".size(), " + var + ".at(" + num + ") is out of bounds.");
else
reportError(tok, Severity::error, "stlOutOfBounds", "When " + num + "==" + var + ".size(), " + var + "[" + num + "] is out of bounds.");
}
void CheckStl::erase()
{
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::eFor && Token::simpleMatch(i->classDef, "for (")) {
const Token *tok = i->classDef->linkAt(1);
if (!Token::Match(tok->tokAt(-3), "; ++| %var% ++| ) {"))
continue;
tok = tok->previous();
if (!tok->isName())
tok = tok->previous();
eraseCheckLoopVar(*i, tok->variable());
} else if (i->type == Scope::eWhile && Token::Match(i->classDef, "while ( %var% !=")) {
eraseCheckLoopVar(*i, i->classDef->tokAt(2)->variable());
}
}
}
void CheckStl::eraseCheckLoopVar(const Scope &scope, const Variable *var)
{
if (!var || !Token::simpleMatch(var->typeEndToken(), "iterator"))
return;
for (const Token *tok = scope.classStart; tok != scope.classEnd; tok = tok->next()) {
if (tok->str() != "(")
continue;
if (!Token::Match(tok->tokAt(-2), ". erase ( ++| %varid% )", var->declarationId()))
continue;
if (Token::simpleMatch(tok->astParent(), "="))
continue;
// Iterator is invalid..
unsigned int indentlevel = 0U;
const Token *tok2 = tok->link();
for (; tok2 != scope.classEnd; tok2 = tok2->next()) {
if (tok2->str() == "{") {
++indentlevel;
continue;
}
if (tok2->str() == "}") {
if (indentlevel > 0U)
--indentlevel;
else if (Token::simpleMatch(tok2, "} else {"))
tok2 = tok2->linkAt(2);
continue;
}
if (tok2->varId() == var->declarationId()) {
if (Token::simpleMatch(tok2->next(), "="))
break;
dereferenceErasedError(tok, tok2, tok2->str());
break;
}
if (indentlevel == 0U && Token::Match(tok2, "break|return|goto"))
break;
}
if (tok2 == scope.classEnd)
dereferenceErasedError(tok, scope.classDef, var->nameToken()->str());
}
}
void CheckStl::pushback()
{
// Pointer can become invalid after push_back, push_front, reserve or resize..
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()) {
if (Token::Match(tok, "%var% = & %var% [")) {
// Variable id for pointer
const unsigned int pointerId(tok->varId());
// Variable id for the container variable
const unsigned int containerId(tok->tokAt(3)->varId());
bool invalidPointer = false;
const Token* function = nullptr;
const Token* end2 = tok->scope()->classEnd;
for (const Token *tok2 = tok; tok2 != end2; tok2 = tok2->next()) {
// push_back on vector..
if (Token::Match(tok2, "%varid% . push_front|push_back|insert|reserve|resize|clear", containerId)) {
invalidPointer = true;
function = tok2->tokAt(2);
}
// Using invalid pointer..
if (invalidPointer && tok2->varId() == pointerId) {
bool unknown = false;
if (CheckNullPointer::isPointerDeRef(tok2, unknown))
invalidPointerError(tok2, function->str(), tok2->str());
break;
}
}
}
}
}
// Iterator becomes invalid after reserve, resize, insert, push_back or push_front..
for (unsigned int iteratorId = 1; iteratorId < symbolDatabase->getVariableListSize(); iteratorId++) {
const Variable* var = symbolDatabase->getVariableFromVarId(iteratorId);
// Check that its an iterator
if (!var || !var->isLocal() || !Token::Match(var->typeEndToken(), "iterator|const_iterator|reverse_iterator|const_reverse_iterator"))
continue;
// ... on std::vector
if (!Token::Match(var->typeStartToken(), "std| ::| vector <"))
continue;
// the variable id for the vector
unsigned int vectorid = 0;
const Token* validatingToken = 0;
std::string invalidIterator;
const Token* end2 = var->scope()->classEnd;
for (const Token *tok2 = var->nameToken(); tok2 != end2; tok2 = tok2->next()) {
if (validatingToken == tok2) {
invalidIterator.clear();
validatingToken = 0;
}
// Using push_back or push_front inside a loop..
if (Token::simpleMatch(tok2, "for (")) {
tok2 = tok2->tokAt(2);
}
if (Token::Match(tok2, "%varid% = %var% . begin|rbegin|cbegin|crbegin ( ) ; %varid% != %var% . end|rend|cend|crend ( ) ; ++| %varid% ++| ) {", iteratorId)) {
// variable id for the loop iterator
const unsigned int varId(tok2->tokAt(2)->varId());
const Token *pushbackTok = nullptr;
// Count { and } for tok3
const Token *tok3 = tok2->tokAt(20);
for (const Token* const end3 = tok3->linkAt(-1); tok3 != end3; tok3 = tok3->next()) {
if (tok3->str() == "break" || tok3->str() == "return") {
pushbackTok = 0;
break;
} else if (Token::Match(tok3, "%varid% . push_front|push_back|insert|reserve|resize|clear|erase (", varId) && !tok3->previous()->isAssignmentOp()) {
if (tok3->strAt(2) != "erase" || (tok3->tokAt(4)->varId() != iteratorId && tok3->tokAt(5)->varId() != iteratorId)) // This case is handled in: CheckStl::iterators()
pushbackTok = tok3->tokAt(2);
}
}
if (pushbackTok)
invalidIteratorError(pushbackTok, pushbackTok->str(), tok2->str());
}
// Assigning iterator..
if (Token::Match(tok2, "%varid% =", iteratorId)) {
if (Token::Match(tok2->tokAt(2), "%var% . begin|end|rbegin|rend|cbegin|cend|crbegin|crend|insert|erase|find (")) {
if (!invalidIterator.empty() && Token::Match(tok2->tokAt(4), "insert|erase ( *| %varid% )|,", iteratorId)) {
invalidIteratorError(tok2, invalidIterator, var->name());
break;
}
vectorid = tok2->tokAt(2)->varId();
tok2 = tok2->linkAt(5);
} else {
vectorid = 0;
}
invalidIterator = "";
}
// push_back on vector..
if (vectorid > 0 && Token::Match(tok2, "%varid% . push_front|push_back|insert|reserve|resize|clear|erase (", vectorid)) {
if (!invalidIterator.empty() && Token::Match(tok2->tokAt(2), "insert|erase ( *| %varid% ,|)", iteratorId)) {
invalidIteratorError(tok2, invalidIterator, var->name());
break;
}
if (tok2->strAt(2) != "erase" || (tok2->tokAt(4)->varId() != iteratorId && tok2->tokAt(5)->varId() != iteratorId)) // This case is handled in: CheckStl::iterators()
invalidIterator = tok2->strAt(2);
tok2 = tok2->linkAt(3);
}
else if (tok2->str() == "return" || tok2->str() == "throw")
validatingToken = Token::findsimplematch(tok2->next(), ";");
// TODO: instead of bail out for 'else' try to check all execution paths.
else if (tok2->str() == "break" || tok2->str() == "else")
invalidIterator.clear();
// Using invalid iterator..
if (!invalidIterator.empty()) {
if (Token::Match(tok2, "++|--|*|+|-|(|,|=|!= %varid%", iteratorId))
invalidIteratorError(tok2, invalidIterator, tok2->strAt(1));
if (Token::Match(tok2, "%varid% ++|--|+|-|.", iteratorId))
invalidIteratorError(tok2, invalidIterator, tok2->str());
}
}
}
}
// Error message for bad iterator usage..
void CheckStl::invalidIteratorError(const Token *tok, const std::string &func, const std::string &iterator_name)
{
reportError(tok, Severity::error, "invalidIterator2", "After " + func + "(), the iterator '" + iterator_name + "' may be invalid.");
}
// Error message for bad iterator usage..
void CheckStl::invalidPointerError(const Token *tok, const std::string &func, const std::string &pointer_name)
{
reportError(tok, Severity::error, "invalidPointer", "Invalid pointer '" + pointer_name + "' after " + func + "().");
}
void CheckStl::stlBoundaries()
{
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()) {
// Declaring iterator..
if (tok->str() == "<" && Token::Match(tok->previous(), "bitset|list|forward_list|map|multimap|multiset|priority_queue|queue|set|stack|hash_map|hash_multimap|hash_set|unordered_map|unordered_multimap|unordered_set|unordered_multiset")) {
if (!tok->link())
continue;
const std::string& container_name(tok->strAt(-1));
tok = tok->link();
if (Token::Match(tok, "> :: iterator|const_iterator %var% =|;")) {
const unsigned int iteratorid(tok->tokAt(3)->varId());
// Using "iterator < ..." is not allowed
const Token* const end = tok->scope()->classEnd;
for (const Token *tok2 = tok; tok2 != end; tok2 = tok2->next()) {
if (Token::Match(tok2, "!!* %varid% <", iteratorid)) {
stlBoundariesError(tok2, container_name);
} else if (Token::Match(tok2, "> %varid% !!.", iteratorid)) {
stlBoundariesError(tok2, container_name);
}
}
}
}
}
}
}
// Error message for bad boundary usage..
void CheckStl::stlBoundariesError(const Token *tok, const std::string &container_name)
{
reportError(tok, Severity::error, "stlBoundaries",
"Dangerous iterator comparison using operator< on 'std::" + container_name + "'.\n"
"Iterator of container 'std::" + container_name + "' compared with operator<. "
"This is dangerous since the order of items in the container is not guaranteed. "
"One should use operator!= instead to compare iterators.");
}
static bool if_findCompare(const Token * const tokBack)
{
const Token *tok = tokBack->astParent();
if (!tok)
return true;
if (tok->isComparisonOp())
return (!tok->astOperand1()->isNumber() && !tok->astOperand2()->isNumber());
if (tok->isArithmeticalOp()) // result is used in some calculation
return true; // TODO: check if there is a comparison of the result somewhere
if (tok->str() == ".")
return true; // Dereferencing is OK, the programmer might know that the element exists - TODO: An inconclusive warning might be appropriate
if (tok->isAssignmentOp())
return if_findCompare(tok); // Go one step upwards in the AST
return false;
}
void CheckStl::if_find()
{
const bool printWarning = _settings->isEnabled("warning");
const bool printPerformance = _settings->isEnabled("performance");
if (!printWarning && !printPerformance)
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::eIf && i->type != Scope::eWhile) || !i->classDef)
continue;
for (const Token *tok = i->classDef; tok->str() != "{"; tok = tok->next()) {
const Token* funcTok = nullptr;
const Library::Container* container = nullptr;
if (tok->variable() && Token::Match(tok, "%var% . %name% (")) {
container = _settings->library.detectContainer(tok->variable()->typeStartToken());
funcTok = tok->tokAt(2);
}
// check also for vector-like or pointer containers
else if (tok->variable() && tok->astParent() && (tok->astParent()->str() == "*" || tok->astParent()->str() == "[")) {
const Token *tok2 = tok->astParent();
if (!Token::Match(tok2->astParent(), ". %name% ("))
continue;
funcTok = tok2->astParent()->next();
if (tok->variable()->isArrayOrPointer())
container = _settings->library.detectContainer(tok->variable()->typeStartToken());
else { // Container of container - find the inner container
container = _settings->library.detectContainer(tok->variable()->typeStartToken()); // outer container
tok2 = Token::findsimplematch(tok->variable()->typeStartToken(), "<", tok->variable()->typeEndToken());
if (container && container->type_templateArgNo >= 0 && tok2) {
tok2 = tok2->next();
for (int j = 0; j < container->type_templateArgNo; j++)
tok2 = tok2->nextTemplateArgument();
container = _settings->library.detectContainer(tok2); // innner container
} else
container = nullptr;
}
}
if (container && container->getAction(funcTok->str()) == Library::Container::FIND) {
if (if_findCompare(funcTok->next()))
continue;
if (printWarning && !container->stdStringLike)
if_findError(tok, false);
else if (printPerformance && container->stdStringLike)
if_findError(tok, true);
} else if (printWarning && Token::Match(tok, "std :: find|find_if (")) {
// check that result is checked properly
if (!if_findCompare(tok->tokAt(3))) {
if_findError(tok, false);
}
}
}
}
}
void CheckStl::if_findError(const Token *tok, bool str)
{
if (str)
reportError(tok, Severity::performance, "stlIfStrFind",
"Inefficient usage of string::find() in condition; string::compare() would be faster.\n"
"Either inefficient or wrong usage of string::find(). string::compare() will be faster if "
"string::find's result is compared with 0, because it will not scan the whole "
"string. If your intention is to check that there are no findings in the string, "
"you should compare with std::string::npos.");
else
reportError(tok, Severity::warning, "stlIfFind", "Suspicious condition. The result of find() is an iterator, but it is not properly checked.");
}
/**
* Is container.size() slow?
*/
static bool isCpp03ContainerSizeSlow(const Token *tok)
{
if (!tok)
return false;
const Variable* var = tok->variable();
return var && var->isStlType("list");
}
void CheckStl::size()
{
if (!_settings->isEnabled("performance"))
return;
if (_settings->standards.cpp == Standards::CPP11)
return;
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()) {
if (Token::Match(tok, "%var% . size ( )") ||
Token::Match(tok, "%name% . %var% . size ( )")) {
const Token *tok1 = tok;
// get the variable
if (tok->strAt(2) != "size")
tok1 = tok1->tokAt(2);
const Token* const end = tok1->tokAt(5);
// check for comparison to zero
if ((tok->previous() && !tok->previous()->isArithmeticalOp() && Token::Match(end, "==|<=|!=|> 0")) ||
(end->next() && !end->next()->isArithmeticalOp() && Token::Match(tok->tokAt(-2), "0 ==|>=|!=|<"))) {
if (isCpp03ContainerSizeSlow(tok1))
sizeError(tok1);
}
// check for comparison to one
if ((tok->previous() && !tok->previous()->isArithmeticalOp() && Token::Match(end, ">=|< 1") && !end->tokAt(2)->isArithmeticalOp()) ||
(end->next() && !end->next()->isArithmeticalOp() && Token::Match(tok->tokAt(-2), "1 <=|>") && !tok->tokAt(-3)->isArithmeticalOp())) {
if (isCpp03ContainerSizeSlow(tok1))
sizeError(tok1);
}
// check for using as boolean expression
else if ((Token::Match(tok->tokAt(-2), "if|while (") && end->str() == ")") ||
(tok->previous()->tokType() == Token::eLogicalOp && Token::Match(end, "&&|)|,|;|%oror%"))) {
if (isCpp03ContainerSizeSlow(tok1))
sizeError(tok1);
}
}
}
}
}
void CheckStl::sizeError(const Token *tok)
{
const std::string varname = tok ? tok->str() : std::string("list");
reportError(tok, Severity::performance, "stlSize",
"Possible inefficient checking for '" + varname + "' emptiness.\n"
"Checking for '" + varname + "' emptiness might be inefficient. "
"Using " + varname + ".empty() instead of " + varname + ".size() can be faster. " +
varname + ".size() can take linear time but " + varname + ".empty() is "
"guaranteed to take constant time.");
}
void CheckStl::redundantCondition()
{
if (!_settings->isEnabled("style"))
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::eIf)
continue;
const Token* tok = i->classDef->tokAt(2);
if (!Token::Match(tok, "%name% . find ( %any% ) != %name% . end|rend|cend|crend ( ) ) { %name% . remove|erase ( %any% ) ;"))
continue;
// Get tokens for the fields %name% and %any%
const Token *var1 = tok;
const Token *any1 = var1->tokAt(4);
const Token *var2 = any1->tokAt(3);
const Token *var3 = var2->tokAt(7);
const Token *any2 = var3->tokAt(4);
// Check if all the "%name%" fields are the same and if all the "%any%" are the same..
if (var1->str() == var2->str() &&
var2->str() == var3->str() &&
any1->str() == any2->str()) {
redundantIfRemoveError(tok);
}
}
}
void CheckStl::redundantIfRemoveError(const Token *tok)
{
reportError(tok, Severity::style, "redundantIfRemove",
"Redundant checking of STL container element existence before removing it.\n"
"Redundant checking of STL container element existence before removing it. "
"It is safe to call the remove method on a non-existing element.");
}
void CheckStl::missingComparison()
{
if (!_settings->isEnabled("warning"))
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::eFor || !i->classDef)
continue;
for (const Token *tok2 = i->classDef->tokAt(2); tok2 != i->classStart; tok2 = tok2->next()) {
if (tok2->str() == ";")
break;
if (!Token::Match(tok2, "%var% = %name% . begin|rbegin|cbegin|crbegin ( ) ; %name% != %name% . end|rend|cend|crend ( ) ; ++| %name% ++| ) {"))
continue;
// same container
if (tok2->strAt(2) != tok2->strAt(10))
break;
const unsigned int iteratorId(tok2->varId());
// same iterator
if (iteratorId == tok2->tokAt(10)->varId())
break;
// increment iterator
if (!Token::Match(tok2->tokAt(16), "++ %varid% )", iteratorId) &&
!Token::Match(tok2->tokAt(16), "%varid% ++ )", iteratorId)) {
break;
}
const Token *incrementToken = nullptr;
// Parse loop..
for (const Token *tok3 = i->classStart; tok3 != i->classEnd; tok3 = tok3->next()) {
if (Token::Match(tok3, "%varid% ++", iteratorId))
incrementToken = tok3;
else if (Token::Match(tok3->previous(), "++ %varid% !!.", iteratorId))
incrementToken = tok3;
else if (Token::Match(tok3, "%varid% !=|==", iteratorId))
incrementToken = 0;
else if (tok3->str() == "break" || tok3->str() == "return")
incrementToken = 0;
else if (Token::Match(tok3, "%varid% = %name% . insert ( ++| %varid% ++| ,", iteratorId)) {
// skip insertion..
tok3 = tok3->linkAt(6);
if (!tok3)
break;
}
}
if (incrementToken)
missingComparisonError(incrementToken, tok2->tokAt(16));
}
}
}
void CheckStl::missingComparisonError(const Token *incrementToken1, const Token *incrementToken2)
{
std::list<const Token*> callstack;
callstack.push_back(incrementToken1);
callstack.push_back(incrementToken2);
std::ostringstream errmsg;
errmsg << "Missing bounds check for extra iterator increment in loop.\n"
<< "The iterator incrementing is suspicious - it is incremented at line ";
if (incrementToken1)
errmsg << incrementToken1->linenr();
errmsg << " and then at line ";
if (incrementToken2)
errmsg << incrementToken2->linenr();
errmsg << ". The loop might unintentionally skip an element in the container. "
<< "There is no comparison between these increments to prevent that the iterator is "
<< "incremented beyond the end.";
reportError(callstack, Severity::warning, "StlMissingComparison", errmsg.str());
}
static bool isLocal(const Token *tok)
{
const Variable *var = tok->variable();
return var && !var->isStatic() && var->isLocal();
}
namespace {
static const std::set<std::string> stl_string = make_container< std::set<std::string> >() <<
"string" << "u16string" << "u32string" << "wstring" ;
static const std::set<std::string> stl_string_stream = make_container< std::set<std::string> >() <<
"istringstream" << "ostringstream" << "stringstream" << "wstringstream" ;
}
void CheckStl::string_c_str()
{
const bool printInconclusive = _settings->inconclusive;
const bool printPerformance = _settings->isEnabled("performance");
const SymbolDatabase* symbolDatabase = _tokenizer->getSymbolDatabase();
// Find all functions that take std::string as argument
std::multimap<std::string, unsigned int> c_strFuncParam;
if (printPerformance) {
for (std::list<Scope>::const_iterator scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {
for (std::list<Function>::const_iterator func = scope->functionList.begin(); func != scope->functionList.end(); ++func) {
if (c_strFuncParam.erase(func->tokenDef->str()) != 0) { // Check if function with this name was already found
c_strFuncParam.insert(std::make_pair(func->tokenDef->str(), 0)); // Disable, because there are overloads. TODO: Handle overloads
continue;
}
unsigned int numpar = 0;
c_strFuncParam.insert(std::make_pair(func->tokenDef->str(), numpar)); // Insert function as dummy, to indicate that there is at least one function with that name
for (const Token* tok = func->argDef->next(); tok != 0; tok = tok->nextArgument()) {
numpar++;
if (Token::Match(tok, "std :: string|wstring !!&") || Token::Match(tok, "const std :: string|wstring"))
c_strFuncParam.insert(std::make_pair(func->tokenDef->str(), numpar));
}
}
}
}
// Try to detect common problems when using string::c_str()
for (std::list<Scope>::const_iterator scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {
if (scope->type != Scope::eFunction || !scope->function)
continue;
enum {charPtr, stdString, stdStringConstRef, Other} returnType = Other;
if (Token::Match(scope->function->tokenDef->tokAt(-2), "char|wchar_t *"))
returnType = charPtr;
else if (Token::Match(scope->function->tokenDef->tokAt(-5), "const std :: string|wstring &"))
returnType = stdStringConstRef;
else if (Token::Match(scope->function->tokenDef->tokAt(-3), "std :: string|wstring !!&"))
returnType = stdString;
for (const Token *tok = scope->classStart; tok && tok != scope->classEnd; tok = tok->next()) {
// Invalid usage..
if (Token::Match(tok, "throw %var% . c_str|data ( ) ;") && isLocal(tok->next()) &&
tok->next()->variable() && tok->next()->variable()->isStlType(stl_string)) {
string_c_strThrowError(tok);
} else if (Token::Match(tok, "[;{}] %name% = %var% . str ( ) . c_str|data ( ) ;")) {
const Variable* var = tok->next()->variable();
const Variable* var2 = tok->tokAt(3)->variable();
if (var && var->isPointer() && var2 && var2->isStlType(stl_string_stream))
string_c_strError(tok);
} else if (Token::Match(tok, "[;{}] %var% = %name% (") &&
Token::Match(tok->linkAt(4), ") . c_str|data ( ) ;") &&
tok->tokAt(3)->function() && Token::Match(tok->tokAt(3)->function()->retDef, "std :: string|wstring %name%")) {
const Variable* var = tok->next()->variable();
if (var && var->isPointer())
string_c_strError(tok);
} else if (printPerformance && Token::Match(tok, "%name% ( !!)") && c_strFuncParam.find(tok->str()) != c_strFuncParam.end() &&
!Token::Match(tok->previous(), "::|.") && tok->varId() == 0 && tok->str() != scope->className) { // calling function. TODO: Add support for member functions
std::pair<std::multimap<std::string, unsigned int>::const_iterator, std::multimap<std::string, unsigned int>::const_iterator> range = c_strFuncParam.equal_range(tok->str());
for (std::multimap<std::string, unsigned int>::const_iterator i = range.first; i != range.second; ++i) {
if (i->second == 0)
continue;
const Token* tok2 = tok->tokAt(2);
unsigned int j;
for (j = 0; tok2 && j < i->second-1; j++)
tok2 = tok2->nextArgument();
if (tok2)
tok2 = tok2->nextArgument();
else
break;
if (!tok2 && j == i->second-1)
tok2 = tok->next()->link();
else
tok2 = tok2->previous();
if (tok2 && Token::Match(tok2->tokAt(-4), ". c_str|data ( )")) {
const Variable* var = tok2->tokAt(-5)->variable();
if (var && var->isStlType(stl_string)) {
string_c_strParam(tok, i->second);
} else if (Token::Match(tok2->tokAt(-9), "%name% . str ( )")) { // Check ss.str().c_str() as parameter
const Variable* ssVar = tok2->tokAt(-9)->variable();
if (ssVar && ssVar->isStlType(stl_string_stream))
string_c_strParam(tok, i->second);
}
}
}
}
// Using c_str() to get the return value is only dangerous if the function returns a char*
if (returnType == charPtr) {
if (Token::Match(tok, "return %var% . c_str|data ( ) ;") && isLocal(tok->next()) &&
tok->next()->variable() && tok->next()->variable()->isStlType(stl_string)) {
string_c_strError(tok);
} else if (Token::Match(tok, "return %var% . str ( ) . c_str|data ( ) ;") && isLocal(tok->next()) &&
tok->next()->variable() && tok->next()->variable()->isStlType(stl_string_stream)) {
string_c_strError(tok);
} else if (Token::Match(tok, "return std :: string|wstring (") &&
Token::Match(tok->linkAt(4), ") . c_str|data ( ) ;")) {
string_c_strError(tok);
} else if (Token::Match(tok, "return %name% (") && Token::Match(tok->linkAt(2), ") . c_str|data ( ) ;")) {
const Function* func = tok->next()->function();
if (func && Token::Match(func->tokenDef->tokAt(-3), "std :: string|wstring"))
string_c_strError(tok);
} else if (Token::simpleMatch(tok, "return (") &&
Token::Match(tok->next()->link(), ") . c_str|data ( ) ;")) {
// Check for "+ localvar" or "+ std::string(" inside the bracket
bool is_implicit_std_string = printInconclusive;
const Token *search_end = tok->next()->link();
for (const Token *search_tok = tok->tokAt(2); search_tok != search_end; search_tok = search_tok->next()) {
if (Token::Match(search_tok, "+ %var%") && isLocal(search_tok->next()) &&
search_tok->next()->variable() && search_tok->next()->variable()->isStlType(stl_string)) {
is_implicit_std_string = true;
break;
} else if (Token::Match(search_tok, "+ std :: string|wstring (")) {
is_implicit_std_string = true;
break;
}
}
if (is_implicit_std_string)
string_c_strError(tok);
}
}
// Using c_str() to get the return value is redundant if the function returns std::string or const std::string&.
else if (printPerformance && (returnType == stdString || returnType == stdStringConstRef)) {
if (tok->str() == "return") {
const Token* tok2 = Token::findsimplematch(tok->next(), ";");
if (Token::Match(tok2->tokAt(-4), ". c_str|data ( )")) {
tok2 = tok2->tokAt(-5);
if (tok2->variable() && tok2->variable()->isStlType(stl_string)) { // return var.c_str();
string_c_strReturn(tok);
}
}
}
}
}
}
}
void CheckStl::string_c_strThrowError(const Token* tok)
{
reportError(tok, Severity::error, "stlcstrthrow", "Dangerous usage of c_str(). The value returned by c_str() is invalid after throwing exception.\n"
"Dangerous usage of c_str(). The string is destroyed after the c_str() call so the thrown pointer is invalid.");
}
void CheckStl::string_c_strError(const Token* tok)
{
reportError(tok, Severity::error, "stlcstr", "Dangerous usage of c_str(). The value returned by c_str() is invalid after this call.\n"
"Dangerous usage of c_str(). The c_str() return value is only valid until its string is deleted.");
}
void CheckStl::string_c_strReturn(const Token* tok)
{
reportError(tok, Severity::performance, "stlcstrReturn", "Returning the result of c_str() in a function that returns std::string is slow and redundant.\n"
"The conversion from const char* as returned by c_str() to std::string creates an unnecessary string copy. Solve that by directly returning the string.");
}
void CheckStl::string_c_strParam(const Token* tok, unsigned int number)
{
std::ostringstream oss;
oss << "Passing the result of c_str() to a function that takes std::string as argument no. " << number << " is slow and redundant.\n"
"The conversion from const char* as returned by c_str() to std::string creates an unnecessary string copy. Solve that by directly passing the string.";
reportError(tok, Severity::performance, "stlcstrParam", oss.str());
}
static bool hasArrayEnd(const Token *tok1)
{
const Token *end = Token::findsimplematch(tok1, ";");
return (end && Token::simpleMatch(end->previous(), "] ;"));
}
static bool hasArrayEndParen(const Token *tok1)
{
const Token *end = Token::findsimplematch(tok1, ";");
return (end && end->previous() &&
Token::simpleMatch(end->tokAt(-2), "] ) ;"));
}
//---------------------------------------------------------------------------
//
//---------------------------------------------------------------------------
void CheckStl::checkAutoPointer()
{
std::set<unsigned int> autoPtrVarId;
std::map<unsigned int, const std::string> mallocVarId; // variables allocated by the malloc-like function
static const char STL_CONTAINER_LIST[] = "array|bitset|deque|list|forward_list|map|multimap|multiset|priority_queue|queue|set|stack|vector|hash_map|hash_multimap|hash_set|unordered_map|unordered_multimap|unordered_set|unordered_multiset|basic_string";
const int malloc = _settings->library.alloc("malloc"); // allocation function, which are not compatible with auto_ptr
const bool printStyle = _settings->isEnabled("style");
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::simpleMatch(tok, "auto_ptr <")) {
if ((tok->strAt(-1) == "<" && Token::Match(tok->tokAt(-2), STL_CONTAINER_LIST)) ||
(Token::simpleMatch(tok->tokAt(-3), "< std :: auto_ptr") && Token::Match(tok->tokAt(-4), STL_CONTAINER_LIST))) {
autoPointerContainerError(tok);
} else {
const Token *tok2 = tok->linkAt(1);
if (Token::Match(tok2, "> %name%")) {
const Token *tok3 = tok2->tokAt(2);
if (Token::Match(tok3, "( new %type%") && hasArrayEndParen(tok3)) {
autoPointerArrayError(tok2->next());
}
if (Token::Match(tok3, "( %name% (") && malloc && _settings->library.alloc(tok3->next()) == malloc) {
// malloc-like function allocated memory passed to the auto_ptr constructor -> error
autoPointerMallocError(tok2->next(), tok3->next()->str());
}
if (Token::Match(tok3, "( %var%")) {
std::map<unsigned int, const std::string>::const_iterator it = mallocVarId.find(tok3->next()->varId());
if (it != mallocVarId.cend()) {
// pointer on the memory allocated by malloc used in the auto pointer constructor -> error
autoPointerMallocError(tok2->next(), it->second);
}
}
while (tok3 && tok3->str() != ";") {
tok3 = tok3->next();
}
if (tok3) {
tok3 = tok3->tokAt(-2);
if (Token::simpleMatch(tok3->previous(), "[ ] )")) {
autoPointerArrayError(tok2->next());
} else if (tok3->varId()) {
const Token *decltok = Token::findmatch(_tokenizer->tokens(), "%varid% = new %type%", tok3->varId());
if (decltok && hasArrayEnd(decltok)) {
autoPointerArrayError(tok2->next());
}
}
if (tok2->next()->varId()) {
autoPtrVarId.insert(tok2->next()->varId());
}
}
}
}
} else {
if (Token::Match(tok, "%name% = %var% ;")) {
if (printStyle) {
std::set<unsigned int>::const_iterator iter = autoPtrVarId.find(tok->tokAt(2)->varId());
if (iter != autoPtrVarId.end()) {
autoPointerError(tok->tokAt(2));
}
}
} else if ((Token::Match(tok, "%var% = new %type%") && hasArrayEnd(tok)) ||
(Token::Match(tok, "%var% . reset ( new %type%") && hasArrayEndParen(tok))) {
std::set<unsigned int>::const_iterator iter = autoPtrVarId.find(tok->varId());
if (iter != autoPtrVarId.end()) {
autoPointerArrayError(tok);
}
} else if (Token::Match(tok, "%var% = %name% (") && malloc && _settings->library.alloc(tok->tokAt(2)) == malloc) {
// C library function like 'malloc' used together with auto pointer -> error
std::set<unsigned int>::const_iterator iter = autoPtrVarId.find(tok->varId());
if (iter != autoPtrVarId.end()) {
autoPointerMallocError(tok, tok->strAt(2));
} else if (tok->varId()) {
// it is not an auto pointer variable and it is allocated by malloc like function.
mallocVarId.insert(std::make_pair(tok->varId(), tok->strAt(2)));
}
} else if (Token::Match(tok, "%var% . reset ( %name% (") && malloc && _settings->library.alloc(tok->tokAt(4)) == malloc) {
// C library function like 'malloc' used when resetting auto pointer -> error
std::set<unsigned int>::const_iterator iter = autoPtrVarId.find(tok->varId());
if (iter != autoPtrVarId.end()) {
autoPointerMallocError(tok, tok->strAt(4));
}
}
}
}
}
void CheckStl::autoPointerError(const Token *tok)
{
reportError(tok, Severity::style, "useAutoPointerCopy",
"Copying 'auto_ptr' pointer to another does not create two equal objects since one has lost its ownership of the pointer.\n"
"'std::auto_ptr' has semantics of strict ownership, meaning that the 'auto_ptr' instance is the sole entity responsible for the object's lifetime. If an 'auto_ptr' is copied, the source looses the reference."
);
}
void CheckStl::autoPointerContainerError(const Token *tok)
{
reportError(tok, Severity::error, "useAutoPointerContainer",
"You can randomly lose access to pointers if you store 'auto_ptr' pointers in an STL container.\n"
"An element of container must be able to be copied but 'auto_ptr' does not fulfill this requirement. You should consider to use 'shared_ptr' or 'unique_ptr'. It is suitable for use in containers, because they no longer copy their values, they move them."
);
}
void CheckStl::autoPointerArrayError(const Token *tok)
{
reportError(tok, Severity::error, "useAutoPointerArray",
"Object pointed by an 'auto_ptr' is destroyed using operator 'delete'. You should not use 'auto_ptr' for pointers obtained with operator 'new[]'.\n"
"Object pointed by an 'auto_ptr' is destroyed using operator 'delete'. This means that you should only use 'auto_ptr' for pointers obtained with operator 'new'. This excludes arrays, which are allocated by operator 'new[]' and must be deallocated by operator 'delete[]'."
);
}
void CheckStl::autoPointerMallocError(const Token *tok, const std::string& allocFunction)
{
const std::string summary = "Object pointed by an 'auto_ptr' is destroyed using operator 'delete'. You should not use 'auto_ptr' for pointers obtained with function '" + allocFunction + "'.";
const std::string verbose = summary + " This means that you should only use 'auto_ptr' for pointers obtained with operator 'new'. This excludes use C library allocation functions (for example '" + allocFunction + "'), which must be deallocated by the appropriate C library function.";
reportError(tok, Severity::error, "useAutoPointerMalloc", summary + "\n" + verbose);
}
namespace {
static const std::set<std::string> stl_containers_with_empty_and_clear = make_container< std::set<std::string> >() <<
"deque" << "forward_list" << "list" <<
"map" << "multimap" << "multiset" << "set" << "string" <<
"unordered_map" << "unordered_multimap" << "unordered_multiset" <<
"unordered_set" << "vector" << "wstring";
}
void CheckStl::uselessCalls()
{
const bool printPerformance = _settings->isEnabled("performance");
const bool printWarning = _settings->isEnabled("warning");
if (!printPerformance && !printWarning)
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 (printWarning && Token::Match(tok, "%var% . compare|find|rfind|find_first_not_of|find_first_of|find_last_not_of|find_last_of ( %name% [,)]") &&
tok->varId() == tok->tokAt(4)->varId()) {
uselessCallsReturnValueError(tok->tokAt(4), tok->str(), tok->strAt(2));
} else if (printPerformance && Token::Match(tok, "%var% . swap ( %name% )") &&
tok->varId() == tok->tokAt(4)->varId()) {
uselessCallsSwapError(tok, tok->str());
} else if (printPerformance && Token::Match(tok, "%var% . substr (") &&
tok->variable() && tok->variable()->isStlType(stl_string)) {
if (Token::Match(tok->tokAt(4), "0| )"))
uselessCallsSubstrError(tok, false);
else if (tok->strAt(4) == "0" && tok->linkAt(3)->strAt(-1) == "npos") {
if (!tok->linkAt(3)->previous()->variable()) // Make sure that its no variable
uselessCallsSubstrError(tok, false);
} else if (Token::simpleMatch(tok->linkAt(3)->tokAt(-2), ", 0 )"))
uselessCallsSubstrError(tok, true);
} else if (printWarning && Token::Match(tok, "[{};] %var% . empty ( ) ;") &&
tok->next()->variable() && tok->next()->variable()->isStlType(stl_containers_with_empty_and_clear))
uselessCallsEmptyError(tok->next());
else if (Token::Match(tok, "[{};] std :: remove|remove_if|unique (") && tok->tokAt(5)->nextArgument())
uselessCallsRemoveError(tok->next(), tok->strAt(3));
}
}
}
void CheckStl::uselessCallsReturnValueError(const Token *tok, const std::string &varname, const std::string &function)
{
std::ostringstream errmsg;
errmsg << "It is inefficient to call '" << varname << "." << function << "(" << varname << ")' as it always returns 0.\n"
<< "'std::string::" << function << "()' returns zero when given itself as parameter "
<< "(" << varname << "." << function << "(" << varname << ")). As it is currently the "
<< "code is inefficient. It is possible either the string searched ('"
<< varname << "') or searched for ('" << varname << "') is wrong.";
reportError(tok, Severity::warning, "uselessCallsCompare", errmsg.str());
}
void CheckStl::uselessCallsSwapError(const Token *tok, const std::string &varname)
{
std::ostringstream errmsg;
errmsg << "It is inefficient to swap a object with itself by calling '" << varname << ".swap(" << varname << ")'\n"
<< "The 'swap()' function has no logical effect when given itself as parameter "
<< "(" << varname << ".swap(" << varname << ")). As it is currently the "
<< "code is inefficient. Is the object or the parameter wrong here?";
reportError(tok, Severity::performance, "uselessCallsSwap", errmsg.str());
}
void CheckStl::uselessCallsSubstrError(const Token *tok, bool empty)
{
if (empty)
reportError(tok, Severity::performance, "uselessCallsSubstr", "Ineffective call of function 'substr' because it returns an empty string.");
else
reportError(tok, Severity::performance, "uselessCallsSubstr", "Ineffective call of function 'substr' because it returns a copy of the object. Use operator= instead.");
}
void CheckStl::uselessCallsEmptyError(const Token *tok)
{
reportError(tok, Severity::warning, "uselessCallsEmpty", "Ineffective call of function 'empty()'. Did you intend to call 'clear()' instead?");
}
void CheckStl::uselessCallsRemoveError(const Token *tok, const std::string& function)
{
reportError(tok, Severity::warning, "uselessCallsRemove", "Return value of std::" + function + "() ignored. Elements remain in container.\n"
"The return value of std::" + function + "() is ignored. This function returns an iterator to the end of the range containing those elements that should be kept. "
"Elements past new end remain valid but with unspecified values. Use the erase method of the container to delete them.");
}
// Check for iterators being dereferenced before being checked for validity.
// E.g. if (*i && i != str.end()) { }
void CheckStl::checkDereferenceInvalidIterator()
{
if (!_settings->isEnabled("warning"))
return;
// Iterate over "if", "while", and "for" conditions where there may
// be an iterator that is dereferenced before being checked for validity.
const std::list<Scope>& scopeList = _tokenizer->getSymbolDatabase()->scopeList;
for (std::list<Scope>::const_iterator i = scopeList.begin(); i != scopeList.end(); ++i) {
if (i->type == Scope::eIf || i->type == Scope::eDo || i->type == Scope::eWhile || i->type == Scope::eFor) {
const Token* const tok = i->classDef;
const Token* startOfCondition = tok->next();
if (i->type == Scope::eDo)
startOfCondition = startOfCondition->link()->tokAt(2);
if (!startOfCondition) // ticket #6626 invalid code
continue;
const Token* endOfCondition = startOfCondition->link();
if (!endOfCondition)
continue;
// For "for" loops, only search between the two semicolons
if (i->type == Scope::eFor) {
startOfCondition = Token::findsimplematch(tok->tokAt(2), ";", endOfCondition);
if (!startOfCondition)
continue;
endOfCondition = Token::findsimplematch(startOfCondition->next(), ";", endOfCondition);
if (!endOfCondition)
continue;
}
// Only consider conditions composed of all "&&" terms and
// conditions composed of all "||" terms
const bool isOrExpression =
Token::findsimplematch(startOfCondition, "||", endOfCondition) != 0;
const bool isAndExpression =
Token::findsimplematch(startOfCondition, "&&", endOfCondition) != 0;
// Look for a check of the validity of an iterator
const Token* validityCheckTok = 0;
if (!isOrExpression && isAndExpression) {
validityCheckTok =
Token::findmatch(startOfCondition, "&& %var% != %name% . end|rend|cend|crend ( )", endOfCondition);
} else if (isOrExpression && !isAndExpression) {
validityCheckTok =
Token::findmatch(startOfCondition, "%oror% %var% == %name% . end|rend|cend|crend ( )", endOfCondition);
}
if (!validityCheckTok)
continue;
const unsigned int iteratorVarId = validityCheckTok->next()->varId();
// If the iterator dereference is to the left of the check for
// the iterator's validity, report an error.
const Token* const dereferenceTok =
Token::findmatch(startOfCondition, "* %varid%", validityCheckTok, iteratorVarId);
if (dereferenceTok)
dereferenceInvalidIteratorError(dereferenceTok, dereferenceTok->strAt(1));
}
}
}
void CheckStl::dereferenceInvalidIteratorError(const Token* deref, const std::string &iterName)
{
reportError(deref, Severity::warning,
"derefInvalidIterator", "Possible dereference of an invalid iterator: " + iterName + "\n" +
"Make sure to check that the iterator is valid before dereferencing it - not after.");
}
void CheckStl::readingEmptyStlContainer_parseUsage(const Token* tok, bool map, std::set<unsigned int>& empty, bool noerror)
{
// Check for various conditions for the way stl containers and variables can be used
if (tok->strAt(1) == "=" || (tok->strAt(1) == "[" && Token::simpleMatch(tok->linkAt(1), "] ="))) {
// Assignment (LHS)
empty.erase(tok->varId());
} else if (Token::Match(tok, "%name% [")) {
// Access through operator[]
if (map) { // operator[] inserts an element, if used on a std::map
if (!noerror && tok->strAt(-1) == "=")
readingEmptyStlContainerError(tok);
empty.erase(tok->varId());
} else if (!noerror)
readingEmptyStlContainerError(tok);
} else if (Token::Match(tok, "%name% . %type% (")) {
// Member function call
if (Token::Match(tok->tokAt(2), "find|at|data|c_str|back|front|empty|top|size|count")) { // These functions read from the container
if (!noerror)
readingEmptyStlContainerError(tok);
} else
empty.erase(tok->varId());
} else if (tok->strAt(-1) == "=") {
// Assignment (RHS)
if (!noerror)
readingEmptyStlContainerError(tok);
} else {
// Unknown usage. Assume it is initialized.
empty.erase(tok->varId());
}
}
namespace {
static const std::set<std::string> MAP_STL_CONTAINERS = make_container< std::set<std::string> >() <<
"map" << "multimap" << "unordered_map" << "unordered_multimap" ;
static const std::set<std::string> NONMAP_STL_CONTAINERS = make_container< std::set<std::string> >() <<
"deque" << "forward_list" << "list" << "multiset" << "queue" << "set" << "stack" << "string" << "unordered_multiset" << "unordered_set" << "vector";
}
void CheckStl::readingEmptyStlContainer()
{
if (!_settings->isEnabled("style"))
return;
if (!_settings->inconclusive)
return;
std::set<unsigned int> empty_map; // empty std::map-like instances of STL containers
std::set<unsigned int> empty_nonmap; // empty non-std::map-like instances of STL containers
const std::list<Scope>& scopeList = _tokenizer->getSymbolDatabase()->scopeList;
for (std::list<Scope>::const_iterator i = scopeList.begin(); i != scopeList.end(); ++i) {
if (i->type != Scope::eFunction)
continue;
for (const Token *tok = i->classStart->next(); tok != i->classEnd; tok = tok->next()) {
if (Token::Match(tok, "for|while")) { // Loops and end of scope clear the sets.
const Token* tok2 = tok->linkAt(1);
if (!tok2)
continue;
tok2 = tok2->next();
for (const Token* end2 = tok2->link(); tok2 && tok2 != end2; tok2 = tok2->next()) {
if (!tok2->varId())
continue;
const bool map = empty_map.find(tok2->varId()) != empty_map.end();
if (!map && empty_nonmap.find(tok2->varId()) == empty_nonmap.end())
continue;
if (map)
readingEmptyStlContainer_parseUsage(tok2, true, empty_map, true);
else
readingEmptyStlContainer_parseUsage(tok2, false, empty_nonmap, true);
}
} else if (Token::Match(tok, "do|}|break|case")) {
empty_map.clear();
empty_nonmap.clear();
}
if (!tok->varId())
continue;
// Check whether a variable should be marked as "empty"
const Variable* var = tok->variable();
if (var) {
bool insert = false;
if (var->nameToken() == tok && var->isLocal() && !var->isStatic()) { // Local variable declared
insert = !Token::Match(tok->tokAt(1), "[(=]"); // Only if not initialized
} else if (Token::Match(tok, "%name% . clear ( ) ;")) {
insert = true;
}
if (insert) {
if (var->isStlType(MAP_STL_CONTAINERS))
empty_map.insert(var->declarationId());
else if (var->isStlType(NONMAP_STL_CONTAINERS))
empty_nonmap.insert(var->declarationId());
continue;
}
}
const bool map = empty_map.find(tok->varId()) != empty_map.end();
if (!map && empty_nonmap.find(tok->varId()) == empty_nonmap.end())
continue;
if (map)
readingEmptyStlContainer_parseUsage(tok, true, empty_map, false);
else
readingEmptyStlContainer_parseUsage(tok, false, empty_nonmap, false);
}
empty_map.clear();
empty_nonmap.clear();
}
}
void CheckStl::readingEmptyStlContainerError(const Token *tok)
{
reportError(tok, Severity::style, "reademptycontainer", "Reading from empty STL container '" + (tok ? tok->str() : std::string("var")) + "'", 0U, true);
}
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