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cppcheck/lib/checkstl.cpp

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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2010 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 "token.h"
#include "executionpath.h"
// 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::eraseByValueError(const Token *tok, const std::string &containername, const std::string &itername)
{
reportError(tok, Severity::error, "eraseByValue", "Iterator '" + itername + "' becomes invalid when deleted by value from '" + containername + "'");
}
void CheckStl::iterators()
{
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
{
if (!Token::Match(tok, "%var% = %var% . begin ( ) ;|+"))
continue;
const unsigned int iteratorId(tok->varId());
const unsigned int containerId(tok->tokAt(2)->varId());
if (iteratorId == 0 || containerId == 0)
continue;
bool validIterator = true;
unsigned int indent = 0;
for (const Token *tok2 = tok->tokAt(7); tok2; tok2 = tok2->next())
{
if (tok2->str() == "{" && ++indent)
continue;
if (tok2->str() == "}" && --indent == 0)
break;
if (Token::Match(tok2, "%varid% != %var% . end ( )", iteratorId) && tok2->tokAt(2)->varId() != containerId)
{
iteratorsError(tok2, tok->strAt(2), tok2->strAt(2));
tok2 = tok2->tokAt(6);
}
else if (Token::Match(tok2, "%var% . insert|erase ( %varid% )|,", iteratorId))
{
if (!validIterator)
invalidIteratorError(tok2, tok2->strAt(4));
if (tok2->varId() != containerId && tok2->tokAt(5)->str() != ".")
{
// skip error message if container is a set..
if (tok2->varId() > 0)
{
const Token *decltok = Token::findmatch(_tokenizer->tokens(), "%varid%", tok2->varId());
while (decltok && !Token::Match(decltok, "[;{},(]"))
decltok = decltok->previous();
if (Token::Match(decltok, "%any% const| std :: set"))
continue; // No warning
}
// Show error message, mismatching iterator is used.
iteratorsError(tok2, tok->strAt(2), tok2->str());
}
else if (tok2->strAt(2) == std::string("erase"))
validIterator = false;
tok2 = tok2->tokAt(4);
}
else if (Token::Match(tok2, "%varid% = %var% . erase (", iteratorId))
{
validIterator = true;
tok2 = tok2->tokAt(5)->link();
if (!tok2)
break;
}
else if (Token::Match(tok2, "%varid% = %var% ;", iteratorId))
{
validIterator = true;
tok2 = tok2->tokAt(2);
}
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));
}
else if (Token::Match(tok2, "return|break ;"))
{
validIterator = true;
}
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()
{
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
{
if (tok->str() != "std")
continue;
if (Token::Match(tok, "std :: find|find_if|count|transform|replace|replace_if|sort ( %var% . begin|rbegin ( ) , %var% . end|rend ( ) ,"))
{
if (tok->tokAt(4)->str() != tok->tokAt(10)->str())
{
mismatchingContainersError(tok);
}
}
}
}
void CheckStl::stlOutOfBounds()
{
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
{
if (!Token::simpleMatch(tok, "for ("))
continue;
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 ( ) ;"))
{
unsigned int indent2 = 0;
unsigned int numId = tok2->tokAt(1)->varId();
unsigned int varId = tok2->tokAt(3)->varId();
for (const Token *tok3 = tok2->tokAt(8); tok3; tok3 = tok3->next())
{
if (tok3->str() == "{")
++indent2;
else if (tok3->str() == "}")
{
if (indent2 <= 1)
break;
--indent2;
}
else if (tok3->varId() == varId)
{
if (Token::simpleMatch(tok3->next(), ". size ( )"))
break;
else if (Token::Match(tok3->next(), "[ %varid% ]", numId))
stlOutOfBoundsError(tok3, tok3->tokAt(2)->str(), 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() == "(")
++indentlevel;
else if (tok->str() == ")")
--indentlevel;
}
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
{
if (Token::Match(&tok, "[;{}] %var% =") || Token::Match(&tok, "= %var% ;"))
{
ExecutionPath::bailOutVar(checks, tok.next()->varId());
}
if (Token::Match(&tok, "[;{}] break ;"))
{
ExecutionPath::bailOut(checks);
}
if (Token::Match(&tok, "erase ( ++|--| %var% )"))
{
const Token *token = &tok;
while (NULL != (token = token ? token->previous() : 0))
{
if (Token::Match(token, "[;{}]"))
break;
else if (token->str() == "=")
token = 0;
else
token = token->previous();
}
if (token)
{
unsigned int iteratorId = 0;
if (tok.tokAt(2)->isName())
iteratorId = tok.tokAt(2)->varId();
else
iteratorId = tok.tokAt(3)->varId();
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;
}
}
}
}
return &tok;
}
/** @brief going out of scope - all execution paths end */
void end(const std::list<ExecutionPath *> &checks, const Token * /*tok*/) const
{
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% !="))
{
const unsigned int varid = tok2->next()->varId();
if (varid > 0 && Token::findmatch(_tokenizer->tokens(), "> :: iterator %varid%", varid))
EraseCheckLoop::checkScope(this, tok2->next());
}
break;
}
if (Token::Match(tok2, "%var% = %var% . begin ( ) ; %var% != %var% . end ( ) ") &&
tok2->str() == tok2->tokAt(8)->str() &&
tok2->tokAt(2)->str() == tok2->tokAt(10)->str())
{
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 the iterator is invalid so dereferencing it or comparing it with another iterator is invalid.");
}
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% ["))
{
const unsigned int pointerId(tok->varId());
const unsigned int containerId(tok->tokAt(3)->varId());
if (pointerId == 0 || containerId == 0)
continue;
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->tokAt(4)->str() == "=")
{
// skip "> :: iterator|const_iterator"
tok = tok->tokAt(3);
}
unsigned int vectorid = 0;
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::Match(tok2, "for ("))
{
tok2 = tok2->tokAt(2);
}
if (Token::Match(tok2, "%varid% = %var% . begin ( ) ; %varid% != %var% . end ( ) ; ++| %varid% ++| ) {", iteratorid))
{
const unsigned int varId(tok2->tokAt(2)->varId());
if (varId == 0)
continue;
const Token *pushbackTok = 0;
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")
{
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 ( )"))
{
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);
if (!iteratorDeclaredInsideLoop)
{
tok2 = tok2->tokAt(3)->link();
if (!tok2)
break;
}
}
else if (tok2->str() == "return")
{
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..
const std::string checkStr = (std::string(STL_CONTAINER_LIST) + " <");
if (Token::Match(tok, checkStr.c_str()))
{
const std::string container_name(tok->strAt(0));
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", container_name + " range check should use != and not < since the order of the pointers isn't guaranteed");
}
void CheckStl::if_find()
{
if (!_settings->_checkCodingStyle)
return;
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();
if (varid > 0)
{
// Is the variable a std::string or STL container?
const Token * decl = Token::findmatch(_tokenizer->tokens(), "%varid%", varid);
while (decl && !Token::Match(decl, "[;{}(,]"))
decl = decl->previous();
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::style, "stlIfStrFind", "Suspicious condition. string::find will return 0 if the string is found at position 0. If this is what you want to check then string::compare is a faster alternative because it doesn't scan through the string.");
else
reportError(tok, Severity::style, "stlIfFind", "Suspicious condition. The result of find is an iterator, but it is not properly checked.");
}
bool CheckStl::isStlContainer(const Token *tok)
{
// check if this token is defined
if (tok->varId())
{
// find where this token is defined
const Token *type = Token::findmatch(_tokenizer->tokens(), "%varid%", tok->varId());
// find where this tokens type starts
while (type->previous() && !Token::Match(type->previous(), "[;{,(]"))
type = type->previous();
// ignore "const"
if (type->str() == "const")
type = type->next();
// discard namespace if supplied
if (Token::simpleMatch(type, "std ::"))
type = type->next()->next();
// 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->_checkCodingStyle || !_settings->inconclusive)
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
{
if (Token::Match(tok, "%var% . size ( )"))
{
if (Token::Match(tok->tokAt(5), "==|!=|> 0"))
{
if (isStlContainer(tok))
sizeError(tok);
}
else if ((tok->tokAt(5)->str() == ")" ||
tok->tokAt(5)->str() == "&&" ||
tok->tokAt(5)->str() == "||" ||
tok->tokAt(5)->str() == "!") &&
(tok->tokAt(-1)->str() == "(" ||
tok->tokAt(-1)->str() == "&&" ||
tok->tokAt(-1)->str() == "||" ||
tok->tokAt(-1)->str() == "!"))
{
if (tok->tokAt(-1)->str() == "(" &&
tok->tokAt(5)->str() == ")")
{
// check for passing size to function call
if (Token::Match(tok->tokAt(-2), "if|while"))
{
if (isStlContainer(tok))
sizeError(tok);
}
}
else if (isStlContainer(tok))
sizeError(tok);
}
}
}
}
void CheckStl::sizeError(const Token *tok)
{
const std::string varname(tok ? tok->str().c_str() : "list");
const bool verbose(_settings ? _settings->_verbose : true);
reportError(tok, Severity::style, "stlSize", "Use " + varname + ".empty() instead of " + varname + ".size() to guarantee fast code." + (verbose ? " size() can take linear time but empty() is guaranteed to take constant time." : ""));
}
void CheckStl::redundantCondition()
{
const char pattern[] = "if ( %var% . find ( %any% ) != %var% . end ( ) ) "
"{|{|"
" %var% . remove ( %any% ) ; "
"}|}|";
const Token *tok = Token::findmatch(_tokenizer->tokens(), pattern);
while (tok)
{
bool b(tok->tokAt(15)->str() == "{");
// 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 condition. The remove function in the STL will not do anything if element doesn't exist");
}
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