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cppcheck/lib/checkstl.cpp

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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2011 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 "executionpath.h"
#include "symboldatabase.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 both " + container1 + " and " + container2);
}
// Error message used when dereferencing an iterator that has been erased..
void CheckStl::dereferenceErasedError(const Token *tok, const std::string &itername)
{
reportError(tok, Severity::error, "eraseDereference", "Dereferenced iterator '" + itername + "' has been erased");
}
void CheckStl::iterators()
{
// Using same iterator against different containers.
// for (it = foo.begin(); it != bar.end(); ++it)
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
// Locate an iterator..
if (!Token::Match(tok, "%var% = %var% . begin|rbegin|cbegin|crbegin ( ) ;|+"))
continue;
// Get variable ids for both the iterator and container
const unsigned int iteratorId(tok->varId());
const unsigned int containerId(tok->tokAt(2)->varId());
if (iteratorId == 0 || containerId == 0)
continue;
// the validIterator flag says if the iterator has a valid value or not
bool validIterator = true;
// counter for { and }
unsigned int indent = 0;
// Scan through the rest of the code and see if the iterator is
// used against other containers.
for (const Token *tok2 = tok->tokAt(7); tok2; tok2 = tok2->next()) {
// If a { is found then count it and continue
if (tok2->str() == "{" && ++indent)
continue;
// If a } is found then count it. break if indentlevel becomes 0.
if (tok2->str() == "}" && --indent == 0)
break;
// Is iterator compared against different container?
if (Token::Match(tok2, "%varid% != %var% . end|rend|cend|crend ( )", iteratorId) && tok2->tokAt(2)->varId() != containerId) {
iteratorsError(tok2, tok->strAt(2), tok2->strAt(2));
tok2 = tok2->tokAt(6);
}
// Is the iterator used in a insert/erase operation?
else if (Token::Match(tok2, "%var% . insert|erase ( %varid% )|,", iteratorId)) {
// It is bad to insert/erase an invalid iterator
if (!validIterator)
invalidIteratorError(tok2, tok2->strAt(4));
// If insert/erase is used on different container then
// report an error
if (tok2->varId() != containerId && tok2->strAt(5) != ".") {
// skip error message if container is a set..
if (tok2->varId() > 0) {
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
const Variable *variableInfo = symbolDatabase->getVariableFromVarId(tok2->varId());
const Token *decltok = variableInfo ? variableInfo->typeStartToken() : NULL;
if (Token::Match(decltok, "const| std :: set"))
continue; // No warning
}
// Show error message, mismatching iterator is used.
iteratorsError(tok2, tok->strAt(2), tok2->str());
}
// invalidate the iterator if it is erased
else if (tok2->strAt(2) == std::string("erase"))
validIterator = false;
// skip the operation
tok2 = tok2->tokAt(4);
}
// it = foo.erase(..
// taking the result of an erase is ok
else if (Token::Match(tok2, "%varid% = %var% . erase (", iteratorId)) {
// the returned iterator is valid
validIterator = true;
// skip the operation
tok2 = tok2->tokAt(5)->link();
if (!tok2)
break;
}
// Reassign the iterator
else if (Token::Match(tok2, "%varid% = %var% ;", iteratorId)) {
// Assume that the iterator becomes valid.
// TODO: add checking that checks if the iterator becomes valid or not
validIterator = true;
// skip ahead
tok2 = tok2->tokAt(2);
}
// Dereferencing invalid iterator?
else if (!validIterator && Token::Match(tok2, "* %varid%", iteratorId)) {
dereferenceErasedError(tok2, tok2->strAt(1));
tok2 = tok2->next();
} else if (!validIterator && Token::Match(tok2, "%varid% . %var%", iteratorId)) {
dereferenceErasedError(tok2, tok2->strAt(0));
tok2 = tok2->tokAt(2);
} else if (Token::Match(tok2, "%var% . erase ( * %varid%", iteratorId) && tok2->varId() == containerId) {
// eraseByValueError(tok2, tok2->strAt(0), tok2->strAt(5));
}
// bailout handling. Assume that the iterator becomes valid if we see return/break.
// TODO: better handling
else if (Token::Match(tok2, "return|break")) {
validIterator = true;
}
// bailout handling. Assume that the iterator becomes valid if we see else.
// TODO: better handling
else if (tok2->str() == "else") {
validIterator = true;
}
}
}
}
// Error message for bad iterator usage..
void CheckStl::mismatchingContainersError(const Token *tok)
{
reportError(tok, Severity::error, "mismatchingContainers", "mismatching containers");
}
void CheckStl::mismatchingContainers()
{
static const char* const algorithm2_strings[] = { // func(begin1, end1
"adjacent_find", "binary_search", "count", "count_if", "equal", "equal_range", "find", "find_if", "for_each", "generate", "lower_bound", "make_heap",
"max_element", "min_element", "mismatch", "next_permutation", "partition", "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",
"sort", "sort_heap", "stable_partition", "stable_sort", "swap_ranges", "transform", "unique", "unique_copy", "upper_bound"
};
static const char* const algorithm22_strings[] = { // 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"
};
static const char* const algorithm1x1_strings[] = { // func(begin1, x, end1
"inplace_merge", "nth_element", "partial_sort", "rotate", "rotate_copy"
};
static const std::set<std::string> algorithm2(algorithm2_strings, &algorithm2_strings[sizeof(algorithm2_strings) / sizeof(*algorithm2_strings)]);
static const std::set<std::string> algorithm22(algorithm22_strings, &algorithm22_strings[sizeof(algorithm22_strings) / sizeof(*algorithm22_strings)]);
static const std::set<std::string> algorithm1x1(algorithm1x1_strings, &algorithm1x1_strings[sizeof(algorithm1x1_strings) / sizeof(*algorithm1x1_strings)]);
static const std::string iteratorBeginFuncPattern = "begin|cbegin|rbegin|crbegin";
static const std::string iteratorEndFuncPattern = "end|cend|rend|crend";
static const std::string pattern2 = "std :: %type% ( %var% . " + iteratorBeginFuncPattern + " ( ) , %var% . " + iteratorEndFuncPattern + " ( ) ,|)";
static const std::string pattern22 = "std :: %type% ( %var% . " + iteratorBeginFuncPattern + " ( ) , %var% . " + iteratorEndFuncPattern + " ( ) , %var% . " + iteratorBeginFuncPattern + " ( ) , %var% . " + iteratorEndFuncPattern + " ( ) ,|)";
static const std::string pattern1x1_1 = "std :: %type% ( %var% . " + iteratorBeginFuncPattern + " ( ) , ";
static const std::string pattern1x1_2 = ", %var% . " + iteratorEndFuncPattern + " ( ) ,|)";
// Check if different containers are used in various calls of standard functions
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (tok->str() != "std")
continue;
// TODO: If iterator variables are used instead then there are false negatives.
if (Token::Match(tok, pattern2.c_str()) && algorithm2.find(tok->strAt(2)) != algorithm2.end()) {
if (tok->strAt(4) != tok->strAt(10)) {
mismatchingContainersError(tok);
}
tok = tok->tokAt(15);
} else if (Token::Match(tok, pattern22.c_str()) && algorithm22.find(tok->strAt(2)) != algorithm22.end()) {
if (tok->strAt(4) != tok->strAt(10) || tok->strAt(16) != tok->strAt(22)) {
mismatchingContainersError(tok);
}
tok = tok->tokAt(27);
} else if (Token::Match(tok, pattern1x1_1.c_str()) && algorithm1x1.find(tok->strAt(2)) != algorithm1x1.end()) {
// Find third parameter
const Token *tok2 = tok->tokAt(10);
int bracket = 0;
for (; tok2; tok2 = tok2->next()) {
if (tok2->str() == "(")
bracket++;
else if (tok2->str() == ")")
bracket--;
else if (tok2->str() == "," && bracket == 0)
break;
}
if (tok2 && Token::Match(tok2, pattern1x1_2.c_str())) {
if (tok->strAt(4) != tok2->strAt(1)) {
mismatchingContainersError(tok);
}
tok = tok2->tokAt(6);
} else
tok = tok->tokAt(9);
}
}
}
void CheckStl::stlOutOfBounds()
{
// Scan through all tokens..
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
// only interested in "for" loops
if (!Token::simpleMatch(tok, "for ("))
continue;
// check if the for loop condition is wrong
unsigned int indent = 0;
for (const Token *tok2 = tok->tokAt(2); tok2; tok2 = tok2->next()) {
if (tok2->str() == "(")
++indent;
else if (tok2->str() == ")") {
if (indent == 0)
break;
--indent;
}
if (Token::Match(tok2, "; %var% <= %var% . size ( ) ;")) {
// Count { and } for tok3
unsigned int indent3 = 0;
// variable id for loop variable.
unsigned int numId = tok2->tokAt(1)->varId();
// variable id for the container variable
unsigned int varId = tok2->tokAt(3)->varId();
for (const Token *tok3 = tok2->tokAt(8); tok3; tok3 = tok3->next()) {
if (tok3->str() == "{")
++indent3;
else if (tok3->str() == "}") {
if (indent3 <= 1)
break;
--indent3;
} else if (tok3->varId() == varId) {
if (Token::simpleMatch(tok3->next(), ". size ( )"))
break;
else if (Token::Match(tok3->next(), "[ %varid% ]", numId))
stlOutOfBoundsError(tok3, tok3->strAt(2), tok3->str());
}
}
break;
}
}
}
}
// Error message for bad iterator usage..
void CheckStl::stlOutOfBoundsError(const Token *tok, const std::string &num, const std::string &var)
{
reportError(tok, Severity::error, "stlOutOfBounds", "When " + num + "==" + var + ".size(), " + var + "[" + num + "] is out of bounds");
}
/**
* @brief %Check for invalid iterator usage after erase/insert/etc
*/
class EraseCheckLoop : public ExecutionPath {
public:
static void checkScope(CheckStl *checkStl, const Token *it) {
const Token *tok = it;
// Search for the start of the loop body..
int indentlevel = 1;
while (indentlevel > 0 && 0 != (tok = tok->next())) {
if (tok->str() == "(")
tok = tok->link();
else if (tok->str() == ")")
break;
// reassigning iterator in loop head
else if (Token::Match(tok, "%var% =") && tok->str() == it->str())
break;
}
if (! Token::simpleMatch(tok, ") {"))
return;
EraseCheckLoop c(checkStl, it->varId());
std::list<ExecutionPath *> checks;
checks.push_back(c.copy());
ExecutionPath::checkScope(tok->tokAt(2), checks);
c.end(checks, tok->link());
while (!checks.empty()) {
delete checks.back();
checks.pop_back();
}
}
private:
/** Startup constructor */
EraseCheckLoop(Check *o, unsigned int varid)
: ExecutionPath(o, varid), eraseToken(0) {
}
/** @brief token where iterator is erased (non-zero => the iterator is invalid) */
const Token *eraseToken;
/** @brief Copy this check. Called from the ExecutionPath baseclass. */
ExecutionPath *copy() {
return new EraseCheckLoop(*this);
}
/** @brief is another execution path equal? */
bool is_equal(const ExecutionPath *e) const {
const EraseCheckLoop *c = static_cast<const EraseCheckLoop *>(e);
return (eraseToken == c->eraseToken);
}
/** @brief no implementation => compiler error if used by accident */
void operator=(const EraseCheckLoop &);
/** @brief parse tokens */
const Token *parse(const Token &tok, std::list<ExecutionPath *> &checks) const {
// bail out if there are assignments. We don't check the assignments properly.
if (Token::Match(&tok, "[;{}] %var% =") || Token::Match(&tok, "= %var% ;")) {
ExecutionPath::bailOutVar(checks, tok.next()->varId());
}
// the loop stops here. Bail out all execution checks that reach
// this statement
if (Token::Match(&tok, "[;{}] break ;")) {
ExecutionPath::bailOut(checks);
}
// erasing iterator => it is invalidated
if (Token::Match(&tok, "erase ( ++|--| %var% )")) {
// check if there is a "it = ints.erase(it);" pattern. if so
// the it is not invalidated.
const Token *token = &tok;
while (NULL != (token = token ? token->previous() : 0)) {
if (Token::Match(token, "[;{}]"))
break;
else if (token->str() == "=")
token = 0;
}
// the it is invalidated by the erase..
if (token) {
// get variable id for the iterator
unsigned int iteratorId = 0;
if (tok.tokAt(2)->isName())
iteratorId = tok.tokAt(2)->varId();
else
iteratorId = tok.tokAt(3)->varId();
// invalidate this iterator in the corresponding checks
for (std::list<ExecutionPath *>::const_iterator it = checks.begin(); it != checks.end(); ++it) {
EraseCheckLoop *c = dynamic_cast<EraseCheckLoop *>(*it);
if (c && c->varId == iteratorId) {
c->eraseToken = &tok;
}
}
}
}
// don't skip any tokens. return the token that we received.
return &tok;
}
/**
* Parse condition. @sa ExecutionPath::parseCondition
* @param tok first token in condition.
* @param checks The execution paths. All execution paths in the list are executed in the current scope
* @return true => bail out all checking
**/
bool parseCondition(const Token &tok, std::list<ExecutionPath *> &checks) {
// no checking of conditions.
(void)tok;
(void)checks;
return false;
}
/** @brief going out of scope - all execution paths end */
void end(const std::list<ExecutionPath *> &checks, const Token * /*tok*/) const {
// check if there are any invalid iterators. If so there is an error.
for (std::list<ExecutionPath *>::const_iterator it = checks.begin(); it != checks.end(); ++it) {
EraseCheckLoop *c = dynamic_cast<EraseCheckLoop *>(*it);
if (c && c->eraseToken) {
CheckStl *checkStl = dynamic_cast<CheckStl *>(c->owner);
if (checkStl) {
checkStl->eraseError(c->eraseToken);
}
}
}
}
};
void CheckStl::erase()
{
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::simpleMatch(tok, "for (")) {
for (const Token *tok2 = tok->tokAt(2); tok2; tok2 = tok2->next()) {
if (tok2->str() == ";") {
if (Token::Match(tok2, "; %var% !=")) {
// Get declaration token for var..
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
const Variable *variableInfo = symbolDatabase->getVariableFromVarId(tok2->next()->varId());
const Token *decltok = variableInfo ? variableInfo->typeEndToken() : NULL;
// Is variable an iterator?
bool isIterator = false;
if (decltok && Token::Match(decltok->tokAt(-2), "> :: iterator %varid%", tok2->next()->varId()))
isIterator = true;
// If tok2->next() is an iterator, check scope
if (isIterator)
EraseCheckLoop::checkScope(this, tok2->next());
}
break;
}
if (Token::Match(tok2, "%var% = %var% . begin|rbegin|cbegin|crbegin ( ) ; %var% != %var% . end|rend|cend|crend ( )") &&
tok2->str() == tok2->strAt(8) &&
tok2->strAt(2) == tok2->strAt(10)) {
EraseCheckLoop::checkScope(this, tok2);
break;
}
}
}
if (Token::Match(tok, "while ( %var% !=")) {
const unsigned int varid = tok->tokAt(2)->varId();
if (varid > 0 && Token::findmatch(_tokenizer->tokens(), "> :: iterator %varid%", varid))
EraseCheckLoop::checkScope(this, tok->tokAt(2));
}
}
}
// Error message for bad iterator usage..
void CheckStl::eraseError(const Token *tok)
{
reportError(tok, Severity::error, "erase",
"Dangerous iterator usage after erase()-method.\n"
"The iterator is invalid after it has been used in erase() function. "
"Dereferencing or comparing it with another iterator is invalid operation.");
}
void CheckStl::pushback()
{
// Pointer can become invalid after push_back or push_front..
for (const Token *tok = _tokenizer->tokens(); tok; 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());
if (pointerId == 0 || containerId == 0)
continue;
// Count { , } and parentheses for tok2
int indent = 0;
bool invalidPointer = false;
for (const Token *tok2 = tok; indent >= 0 && tok2; tok2 = tok2->next()) {
if (tok2->str() == "{" || tok2->str() == "(")
++indent;
else if (tok2->str() == "}" || tok2->str() == ")") {
if (indent == 0 && Token::simpleMatch(tok2, ") {"))
tok2 = tok2->next();
else
--indent;
}
// push_back on vector..
if (Token::Match(tok2, "%varid% . push_front|push_back", containerId))
invalidPointer = true;
// Using invalid pointer..
if (invalidPointer && tok2->varId() == pointerId) {
if (tok2->previous()->str() == "*")
invalidPointerError(tok2, tok2->str());
else if (tok2->next()->str() == ".")
invalidPointerError(tok2, tok2->str());
break;
}
}
}
}
// Iterator becomes invalid after reserve, push_back or push_front..
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (!Token::simpleMatch(tok, "vector <"))
continue;
// if iterator declaration inside for() loop
bool iteratorDeclaredInsideLoop = false;
if ((tok->tokAt(-2) && Token::simpleMatch(tok->tokAt(-2), "for (")) ||
(tok->tokAt(-4) && Token::simpleMatch(tok->tokAt(-4), "for ( std ::"))) {
iteratorDeclaredInsideLoop = true;
}
while (tok && tok->str() != ">")
tok = tok->next();
if (!tok)
break;
if (!Token::Match(tok, "> :: iterator|const_iterator %var% =|;"))
continue;
const unsigned int iteratorid(tok->tokAt(3)->varId());
if (iteratorid == 0)
continue;
if (iteratorDeclaredInsideLoop && tok->strAt(4) == "=") {
// skip "> :: iterator|const_iterator"
tok = tok->tokAt(3);
}
// the variable id for the vector
unsigned int vectorid = 0;
// count { , } and parentheses for tok2
int indent = 0;
std::string invalidIterator;
for (const Token *tok2 = tok; indent >= 0 && tok2; tok2 = tok2->next()) {
if (tok2->str() == "{" || tok2->str() == "(")
++indent;
else if (tok2->str() == "}" || tok2->str() == ")") {
if (indent == 0 && Token::simpleMatch(tok2, ") {"))
tok2 = tok2->next();
else
--indent;
}
// 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());
if (varId == 0)
continue;
const Token *pushbackTok = 0;
// Count { and } for tok3
unsigned int indent3 = 0;
for (const Token *tok3 = tok2->tokAt(20); tok3; tok3 = tok3->next()) {
if (tok3->str() == "{")
++indent3;
else if (tok3->str() == "}") {
if (indent3 <= 1)
break;
--indent3;
} else if (tok3->str() == "break" || tok3->str() == "return") {
pushbackTok = 0;
break;
} else if (Token::Match(tok3, "%varid% . push_front|push_back|insert|reserve (", varId)) {
pushbackTok = tok3->tokAt(2);
}
}
if (pushbackTok)
invalidIteratorError(pushbackTok, pushbackTok->str(), tok2->strAt(0));
}
// Assigning iterator..
if (Token::Match(tok2, "%varid% =", iteratorid)) {
if (Token::Match(tok2->tokAt(2), "%var% . begin|end|rbegin|rend|cbegin|cend|crbegin|crend ( )")) {
vectorid = tok2->tokAt(2)->varId();
tok2 = tok2->tokAt(6);
} else {
vectorid = 0;
}
invalidIterator = "";
}
// push_back on vector..
if (vectorid > 0 && Token::Match(tok2, "%varid% . push_front|push_back|insert|reserve (", vectorid)) {
if (!invalidIterator.empty() && Token::Match(tok2->tokAt(2), "insert ( %varid% ,", iteratorid)) {
invalidIteratorError(tok2, invalidIterator, tok2->strAt(4));
break;
}
invalidIterator = tok2->strAt(2);
tok2 = tok2->tokAt(3)->link();
}
// TODO: instead of bail out for 'else' try to check all execution paths.
else if (tok2->str() == "return" || 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 &pointer_name)
{
reportError(tok, Severity::error, "invalidPointer", "Invalid pointer '" + pointer_name + "' after push_back / push_front");
}
void CheckStl::stlBoundries()
{
// containers (not the vector)..
static const char STL_CONTAINER_LIST[] = "bitset|deque|list|map|multimap|multiset|priority_queue|queue|set|stack|hash_map|hash_multimap|hash_set";
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
// Declaring iterator..
if (tok->str() == "<" && Token::Match(tok->previous(), STL_CONTAINER_LIST)) {
const std::string container_name(tok->strAt(-1));
while (tok && tok->str() != ">")
tok = tok->next();
if (!tok)
break;
if (Token::Match(tok, "> :: iterator|const_iterator %var% =|;")) {
const unsigned int iteratorid(tok->tokAt(3)->varId());
if (iteratorid == 0)
continue;
// Using "iterator < ..." is not allowed
unsigned int indentlevel = 0;
for (const Token *tok2 = tok; tok2; tok2 = tok2->next()) {
if (tok2->str() == "{")
++indentlevel;
else if (tok2->str() == "}") {
if (indentlevel == 0)
break;
--indentlevel;
} else if (Token::Match(tok2, "!!* %varid% <", iteratorid)) {
stlBoundriesError(tok2, container_name);
}
}
}
}
}
}
// Error message for bad boundry usage..
void CheckStl::stlBoundriesError(const Token *tok, const std::string &container_name)
{
reportError(tok, Severity::error, "stlBoundries",
"Dangerous container iterator compare using < operator for " + container_name + "\n"
"Container '" + container_name + "' iterator compared with < operator. "
"Using < operator with container type iterators is dangerous since the order of "
"the items is not guaranteed. One should use != operator instead when comparing "
"iterators in the container.");
}
void CheckStl::if_find()
{
if (!_settings->isEnabled("style"))
return;
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::Match(tok, "if ( !| %var% . find ( %any% ) )")) {
// goto %var%
tok = tok->tokAt(2);
if (!tok->isName())
tok = tok->next();
const unsigned int varid = tok->varId();
const Variable *var = symbolDatabase->getVariableFromVarId(varid);
if (var) {
// Is the variable a std::string or STL container?
const Token * decl = var->nameToken();
while (decl && !Token::Match(decl, "[;{}(,]"))
decl = decl->previous();
if (decl)
decl = decl->next();
// stl container
if (Token::Match(decl, "const| std :: %var% < %type% > &|*| %varid%", varid))
if_findError(tok, false);
else if (Token::Match(decl, "const| std :: string &|*| %varid%", varid))
if_findError(tok, true);
}
}
if (Token::Match(tok, "if ( !| std :: find|find_if (")) {
// goto '(' for the find
tok = tok->tokAt(4);
if (tok->isName())
tok = tok->next();
// check that result is checked properly
if (Token::simpleMatch(tok->link(), ") )")) {
if_findError(tok, false);
}
}
}
}
void CheckStl::if_findError(const Token *tok, bool str)
{
if (str)
reportError(tok, Severity::warning, "stlIfStrFind",
"Suspicious checking of string::find() return value.\n"
"Checking of string::find() return value looks Suspicious. "
"string::find will return 0 if the string is found at position 0. "
"If that is wanted to check then string::compare is a faster alternative "
"because it doesn't scan through the string.");
else
reportError(tok, Severity::warning, "stlIfFind", "Suspicious condition. The result of find is an iterator, but it is not properly checked.");
}
bool CheckStl::isStlContainer(unsigned int varid)
{
// check if this token is defined
if (varid) {
// find where this token is defined
const Variable *var = _tokenizer->getSymbolDatabase()->getVariableFromVarId(varid);
if (!var)
return false;
// find where this tokens type starts
const Token *type = var->typeStartToken();
// ignore "const"
if (type->str() == "const")
type = type->next();
// discard namespace if supplied
if (Token::simpleMatch(type, "std ::"))
type = type->tokAt(2);
// all possible stl containers
static const char STL_CONTAINER_LIST[] = "bitset|deque|list|map|multimap|multiset|priority_queue|queue|set|stack|hash_map|hash_multimap|hash_set|vector";
// container template string
const std::string checkStr(std::string(STL_CONTAINER_LIST) + " <");
// check if it's an stl template
if (Token::Match(type, checkStr.c_str()))
return true;
}
return false;
}
void CheckStl::size()
{
if (!_settings->isEnabled("performance"))
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::Match(tok, "%var% . size ( )") ||
Token::Match(tok, "%var% . %var% . size ( )")) {
int offset = 5;
const Token *tok1 = tok;
unsigned int varid = 0;
// get the variable id
if (tok->strAt(2) != "size") {
offset = 7;
tok1 = tok1->tokAt(2);
// found a.b.size(), lookup class/struct variable
const Variable *var = _tokenizer->getSymbolDatabase()->getVariableFromVarId(tok->varId());
if (var && var->type()) {
// get class/struct variable type
const Scope *type = var->type();
// lookup variable member
std::list<Variable>::const_iterator it;
for (it = type->varlist.begin(); it != type->varlist.end(); ++it) {
if (it->name() == tok1->str()) {
// found member variable, save varid
varid = it->varId();
break;
}
}
}
} else
varid = tok1->varId();
if (varid) {
// check for comparison to zero
if (Token::Match(tok->tokAt(offset), "==|!=|> 0") ||
Token::Match(tok->tokAt(-2), "0 ==|!=|<")) {
if (isStlContainer(varid))
sizeError(tok1);
}
// check for using as boolean expression
else if ((Token::Match(tok->tokAt(-2), "if|while (") ||
Token::Match(tok->tokAt(-3), "if|while ( !")) &&
tok->strAt(offset) == ")") {
if (isStlContainer(varid))
sizeError(tok1);
}
}
}
}
}
void CheckStl::sizeError(const Token *tok)
{
const std::string varname(tok ? tok->str().c_str() : "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()
{
const char pattern[] = "if ( %var% . find ( %any% ) != %var% . end|rend ( ) ) "
"{|{|"
" %var% . remove ( %any% ) ; "
"}|}|";
const Token *tok = Token::findmatch(_tokenizer->tokens(), pattern);
while (tok) {
bool b(tok->strAt(15) == "{");
// Get tokens for the fields %var% and %any%
const Token *var1 = tok->tokAt(2);
const Token *any1 = tok->tokAt(6);
const Token *var2 = tok->tokAt(9);
const Token *var3 = tok->tokAt(b ? 16 : 15);
const Token *any2 = tok->tokAt(b ? 20 : 19);
// Check if all the "%var%" 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);
}
tok = Token::findmatch(tok->next(), pattern);
}
}
void CheckStl::redundantIfRemoveError(const Token *tok)
{
reportError(tok, Severity::style, "redundantIfRemove",
"Redundant checking of STL container element.\n"
"Redundant checking of STL container element existence before removing it. "
"The remove method in the STL will not do anything if element doesn't exist");
}
void CheckStl::missingComparison()
{
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::simpleMatch(tok, "for (")) {
for (const Token *tok2 = tok->tokAt(2); tok2; tok2 = tok2->next()) {
if (tok2->str() == ";")
break;
if (!Token::Match(tok2, "%var% = %var% . begin|rbegin|cbegin|crbegin ( ) ; %var% != %var% . end|rend|cend|crend ( ) ; ++| %var% ++| ) {"))
continue;
// same iterator name
if (tok2->str() != tok2->strAt(8))
continue;
// same container
if (tok2->strAt(2) != tok2->strAt(10))
continue;
// increment iterator
if (!Token::simpleMatch(tok2->tokAt(16), ("++ " + tok2->str() + " )").c_str()) &&
!Token::simpleMatch(tok2->tokAt(16), (tok2->str() + " ++ )").c_str())) {
continue;
}
const unsigned int &iteratorId(tok2->varId());
if (iteratorId == 0)
continue;
const Token *incrementToken = 0;
// Count { and } for tok3
unsigned int indentlevel = 0;
// Parse loop..
for (const Token *tok3 = tok2->tokAt(20); tok3; tok3 = tok3->next()) {
if (tok3->str() == "{")
++indentlevel;
else if (tok3->str() == "}") {
if (indentlevel == 0)
break;
--indentlevel;
} else 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% = %var% . insert ( ++| %varid% ++| ,", iteratorId)) {
// skip insertion..
tok3 = tok3->tokAt(6)->link();
if (!tok3)
break;
}
}
if (incrementToken)
missingComparisonError(incrementToken, tok2->tokAt(16));
}
}
}
}
void CheckStl::missingComparisonError(const Token *incrementToken1, const Token *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 "
<< incrementToken1->linenr() << " and then at line " << incrementToken2->linenr()
<< " 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(incrementToken1, Severity::warning, "StlMissingComparison", errmsg.str());
}
void CheckStl::string_c_str()
{
// Try to detect common problems when using string::c_str()
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
// Locate executable scopes:
if (Token::Match(tok, ") const| {")) {
std::set<unsigned int> localvar;
std::set<unsigned int> pointers;
// scan through this executable scope:
unsigned int indentlevel = 0;
while (NULL != (tok = tok->next())) {
if (tok->str() == "{")
++indentlevel;
else if (tok->str() == "}") {
if (indentlevel <= 1)
break;
--indentlevel;
}
// Variable declarations..
else if (Token::Match(tok->previous(), "[;{}] std :: %type% %var% ;"))
localvar.insert(tok->tokAt(3)->varId());
else if (Token::Match(tok->previous(), "[;{}] %type% %var% ;"))
localvar.insert(tok->next()->varId());
else if (Token::Match(tok->previous(), "[;{}] %type% * %var% ;"))
pointers.insert(tok->tokAt(2)->varId());
else if (Token::Match(tok->previous(), "[;{}] %type% %type% * %var% ;"))
pointers.insert(tok->tokAt(3)->varId());
// Invalid usage..
else if (Token::Match(tok, "throw %var% . c_str ( ) ;") &&
tok->next()->varId() > 0 &&
localvar.find(tok->next()->varId()) != localvar.end()) {
string_c_strError(tok);
} else if (Token::Match(tok, "[;{}] %var% = %var% . str ( ) . c_str ( ) ;") &&
tok->next()->varId() > 0 &&
pointers.find(tok->next()->varId()) != pointers.end()) {
string_c_strError(tok);
} else if (Token::Match(tok, "[;{}] %var% = %var% (") &&
Token::simpleMatch(tok->tokAt(4)->link(), ") . c_str ( ) ;") &&
tok->next()->varId() > 0 &&
pointers.find(tok->next()->varId()) != pointers.end() &&
Token::findmatch(_tokenizer->tokens(), ("std :: string " + tok->strAt(3) + " (").c_str())) {
string_c_strError(tok);
}
// This part is inconclusive as the return type of the function
// might convert it to another string class implicitly.
// TODO: As soon as the symbol database stores the return value
// of a function, we can check if it's const char* and output a real error.
if (!_settings->inconclusive)
continue;
if (Token::Match(tok, "return %var% . c_str ( ) ;") &&
tok->next()->varId() > 0 &&
localvar.find(tok->next()->varId()) != localvar.end()) {
string_c_strError(tok, true);
} else if (Token::Match(tok, "return %var% . str ( ) . c_str ( ) ;") &&
tok->next()->varId() > 0 &&
localvar.find(tok->next()->varId()) != localvar.end()) {
string_c_strError(tok, true);
} else if (Token::simpleMatch(tok, "return std :: string (") &&
Token::simpleMatch(tok->tokAt(4)->link(), ") . c_str ( ) ;")) {
string_c_strError(tok, true);
} else if (Token::simpleMatch(tok, "return (") &&
Token::simpleMatch(tok->next()->link(), ") . c_str ( ) ;")) {
// Check for "+ localvar" or "+ std::string(" inside the bracket
bool is_implicit_std_string = false;
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%") && search_tok->next()->varId() > 0 &&
localvar.find(search_tok->next()->varId()) != localvar.end()) {
is_implicit_std_string = true;
break;
} else if (Token::simpleMatch(search_tok, "+ std :: string (")) {
is_implicit_std_string = true;
break;
}
}
if (is_implicit_std_string)
string_c_strError(tok, true);
}
}
}
}
}
void CheckStl::string_c_strError(const Token* tok, bool is_inconlusive)
{
if (is_inconlusive)
reportInconclusiveError(tok, Severity::error, "stlcstr", "Possible dangerous usage of c_str()");
else
reportError(tok, Severity::error, "stlcstr", "Dangerous usage of c_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::set<unsigned int>::const_iterator iter;
static const char STL_CONTAINER_LIST[] = "bitset|deque|list|map|multimap|multiset|priority_queue|queue|set|stack|hash_map|hash_multimap|hash_set|vector";
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::simpleMatch(tok, "auto_ptr <")) {
if ((tok->previous() && tok->previous()->str() == "<" && 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->tokAt(2);
while (tok2) {
if (Token::Match(tok2, "> %var%")) {
const Token *tok3 = tok2->tokAt(2);
if (Token::Match(tok3, "( new %type%") && hasArrayEndParen(tok3)) {
autoPointerArrayError(tok2->next());
break;
}
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());
}
break;
}
}
tok2 = tok2->next();
}
}
} else {
if (Token::Match(tok, "%var% = %var% ;")) {
if (_settings->isEnabled("style")) {
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))) {
iter = autoPtrVarId.find(tok->varId());
if (iter != autoPtrVarId.end()) {
autoPointerArrayError(tok);
}
}
}
}
}
void CheckStl::autoPointerError(const Token *tok)
{
reportError(tok, Severity::style, "useAutoPointerCopy",
"Copy 'auto_ptr' pointer to another do not create two equal objects since one has lost its ownership of the pointer.\n"
"The 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 loses 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 a container because the copy-semantics of 'auto_ptr' are not compatible with containers.\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::uselessCalls()
{
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (tok->varId() == 0)
continue;
/*if (Token::Match(tok, "%var% . compare (") &&
tok->varId() == tok->tokAt(3)->link()->tokAt(-1)->varId()) {
uselessCallsReturnValueError(tok, tok->tokAt(2));
} else */
if (Token::Match(tok, "%var% . compare|find|rfind|find_first_not_of|find_first_of|find_last_not_of|find_last_of ( %var% [,)]") &&
tok->varId() == tok->tokAt(4)->varId()) {
uselessCallsReturnValueError(tok->tokAt(4), tok->str(), tok->strAt(2));
} else if (Token::Match(tok, "%var% . swap ( %var% )") &&
tok->varId() == tok->tokAt(4)->varId()) {
uselessCallsSwapError(tok, tok->str());
} else if (Token::Match(tok, "%var% . substr ( )")) {
uselessCallsSubstrError(tok, tok->str());
} else if (Token::Match(tok, "%var% . substr ( 0")) {
if (tok->strAt(5) == ")" ||
tok->tokAt(3)->link()->strAt(-1) == "npos")
uselessCallsSubstrError(tok, tok->str());
}
}
}
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"
<< "The 'std::string::" << function << "()' returns zero when given itself as parameter "
<< "(" << varname << "." << function << "(" << varname << ")). As it is currently the "
<< "code is inefficient. It is also possible either the string searched ('"
<< varname << "') or searched for ('" << varname << "') is wrong/mixed in the code?";
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. It is possible either the object or the parameter is wrong/mixed in the code?";
reportError(tok, Severity::performance, "uselessCallsSwap", errmsg.str());
}
void CheckStl::uselessCallsSubstrError(const Token *tok, const std::string &varname)
{
std::ostringstream errmsg;
errmsg << "Function \'substr\' useless call. Function create copy of the \'" << varname << "\' object.\n" <<
"Function \'substr\' useless call. \'substr\' function create copy of the whole \'" << varname << "\' object which can decrease in performance. Please use \'=\' operator instead.";
reportError(tok, Severity::performance, "uselessCallsSubstr", errmsg.str());
}
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