/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2018 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 "checknullpointer.h"
#include "errorlogger.h"
#include "settings.h"
#include "standards.h"
#include "symboldatabase.h"
#include "token.h"
#include "utils.h"
#include "astutils.h"
#include <cstddef>
#include <list>
#include <map>
#include <set>
#include <sstream>
#include <utility>
// Register this check class (by creating a static instance of it)
namespace {
CheckStl instance;
}
// CWE IDs used:
static const struct CWE CWE398(398U); // Indicator of Poor Code Quality
static const struct CWE CWE597(597U); // Use of Wrong Operator in String Comparison
static const struct CWE CWE628(628U); // Function Call with Incorrectly Specified Arguments
static const struct CWE CWE664(664U); // Improper Control of a Resource Through its Lifetime
static const struct CWE CWE704(704U); // Incorrect Type Conversion or Cast
static const struct CWE CWE762(762U); // Mismatched Memory Management Routines
static const struct CWE CWE786(786U); // Access of Memory Location Before Start of Buffer
static const struct CWE CWE788(788U); // Access of Memory Location After End of Buffer
static const struct CWE CWE825(825U); // Expired Pointer Dereference
static const struct CWE CWE834(834U); // Excessive Iteration
void CheckStl::outOfBounds()
{
for (const Scope *function : mTokenizer->getSymbolDatabase()->functionScopes) {
for (const Token *tok = function->bodyStart; tok != function->bodyEnd; tok = tok->next()) {
if (!tok->isName() || !tok->valueType())
continue;
const Library::Container *container = tok->valueType()->container;
if (!container)
continue;
for (const ValueFlow::Value &value : tok->values()) {
if (!value.isContainerSizeValue())
continue;
if (value.isInconclusive() && !mSettings->inconclusive)
continue;
if (!value.errorSeverity() && !mSettings->isEnabled(Settings::WARNING))
continue;
if (value.intvalue == 0 && Token::Match(tok, "%name% . %name% (") && container->getYield(tok->strAt(2)) == Library::Container::Yield::ITEM) {
outOfBoundsError(tok, &value, nullptr);
continue;
}
if (!container->arrayLike_indexOp && !container->stdStringLike)
continue;
if (value.intvalue == 0 && Token::Match(tok, "%name% [")) {
outOfBoundsError(tok, &value, nullptr);
continue;
}
if (container->arrayLike_indexOp && Token::Match(tok, "%name% [")) {
const ValueFlow::Value *indexValue = tok->next()->astOperand2() ? tok->next()->astOperand2()->getMaxValue(false) : nullptr;
if (indexValue && indexValue->intvalue >= value.intvalue) {
outOfBoundsError(tok, &value, indexValue);
continue;
}
if (mSettings->isEnabled(Settings::WARNING)) {
indexValue = tok->next()->astOperand2() ? tok->next()->astOperand2()->getMaxValue(true) : nullptr;
if (indexValue && indexValue->intvalue >= value.intvalue) {
outOfBoundsError(tok, &value, indexValue);
continue;
}
}
}
}
}
}
}
void CheckStl::outOfBoundsError(const Token *tok, const ValueFlow::Value *containerSize, const ValueFlow::Value *index)
{
// Do not warn if both the container size and index are possible
if (containerSize && index && containerSize->isPossible() && index->isPossible())
return;
const std::string varname = tok ? tok->str() : std::string("var");
std::string errmsg;
if (!containerSize)
errmsg = "Out of bounds access of item in container '$symbol'";
else if (containerSize->intvalue == 0) {
if (containerSize->condition)
errmsg = "Accessing an item in container '$symbol'. " + ValueFlow::eitherTheConditionIsRedundant(containerSize->condition) + " or '$symbol' can be empty.";
else
errmsg = "Accessing an item in container '$symbol' that is empty.";
} else if (index) {
if (containerSize->condition || index->condition)
errmsg = "Possible access out of bounds";
else
errmsg = "Access out of bounds";
errmsg += " of container '$symbol'; size=" +
MathLib::toString(containerSize->intvalue) + ", index=" +
MathLib::toString(index->intvalue);
} else {
// should not happen
return;
}
ErrorPath errorPath;
if (!index)
errorPath = getErrorPath(tok, containerSize, "Access out of bounds");
else {
ErrorPath errorPath1 = getErrorPath(tok, containerSize, "Access out of bounds");
ErrorPath errorPath2 = getErrorPath(tok, index, "Access out of bounds");
if (errorPath1.size() <= 1)
errorPath = errorPath2;
else if (errorPath2.size() <= 1)
errorPath = errorPath1;
else {
errorPath = errorPath1;
errorPath.splice(errorPath.end(), errorPath2);
}
}
reportError(errorPath,
(containerSize && !containerSize->errorSeverity()) || (index && !index->errorSeverity()) ? Severity::warning : Severity::error,
"containerOutOfBounds",
"$symbol:" + varname +"\n" + errmsg,
CWE398,
(containerSize && containerSize->isInconclusive()) || (index && index->isInconclusive()));
}
// Error message for bad iterator usage..
void CheckStl::invalidIteratorError(const Token *tok, const std::string &iteratorName)
{
reportError(tok, Severity::error, "invalidIterator1", "$symbol:"+iteratorName+"\nInvalid iterator: $symbol", CWE664, false);
}
void CheckStl::iteratorsError(const Token* tok, const std::string& containerName1, const std::string& containerName2)
{
reportError(tok, Severity::error, "iterators1",
"$symbol:" + containerName1 + "\n"
"$symbol:" + containerName2 + "\n"
"Same iterator is used with different containers '" + containerName1 + "' and '" + containerName2 + "'.", CWE664, false);
}
void CheckStl::iteratorsError(const Token* tok, const Token* containerTok, const std::string& containerName1, const std::string& containerName2)
{
std::list<const Token*> callstack = { tok, containerTok };
reportError(callstack, Severity::error, "iterators2",
"$symbol:" + containerName1 + "\n"
"$symbol:" + containerName2 + "\n"
"Same iterator is used with different containers '" + containerName1 + "' and '" + containerName2 + "'.", CWE664, false);
}
void CheckStl::iteratorsError(const Token* tok, const Token* containerTok, const std::string& containerName)
{
std::list<const Token*> callstack = { tok, containerTok };
reportError(callstack, Severity::error, "iterators3",
"$symbol:" + containerName + "\n"
"Same iterator is used with containers '" + containerName + "' that are defined in different scopes.", CWE664, false);
}
void CheckStl::iteratorsCmpError(const Token* cmpOperatorTok, const Token* containerTok1, const Token* containerTok2, const std::string& containerName1, const std::string& containerName2)
{
std::list<const Token*> callstack = { cmpOperatorTok, containerTok1, containerTok2 };
reportError(callstack, Severity::error, "iteratorsCmp1",
"$symbol:" + containerName1 + "\n"
"$symbol:" + containerName2 + "\n"
"Comparison of iterators from containers '" + containerName1 + "' and '" + containerName2 + "'.", CWE664, false);
}
void CheckStl::iteratorsCmpError(const Token* cmpOperatorTok, const Token* containerTok1, const Token* containerTok2, const std::string& containerName)
{
std::list<const Token*> callstack = { cmpOperatorTok, containerTok1, containerTok2 };
reportError(callstack, Severity::error, "iteratorsCmp2",
"$symbol:" + containerName + "\n"
"Comparison of iterators from containers '" + containerName + "' that are defined in different scopes.", CWE664, false);
}
// Error message used when dereferencing an iterator that has been erased..
void CheckStl::dereferenceErasedError(const Token *erased, const Token* deref, const std::string &itername, bool inconclusive)
{
if (erased) {
std::list<const Token*> callstack = { deref, erased };
reportError(callstack, Severity::error, "eraseDereference",
"$symbol:" + itername + "\n"
"Iterator '$symbol' used after element has been erased.\n"
"The iterator '$symbol' is invalid after the element it pointed to has been erased. "
"Dereferencing or comparing it with another iterator is invalid operation.", CWE664, inconclusive);
} else {
reportError(deref, Severity::error, "eraseDereference",
"$symbol:" + itername + "\n"
"Invalid iterator '$symbol' used.\n"
"The iterator '$symbol' is invalid before being assigned. "
"Dereferencing or comparing it with another iterator is invalid operation.", CWE664, inconclusive);
}
}
static const Token *skipMembers(const Token *tok)
{
while (Token::Match(tok, "%name% ."))
tok = tok->tokAt(2);
return tok;
}
static bool isIterator(const Variable *var, bool& inconclusiveType)
{
// Check that its an iterator
if (!var || !var->isLocal() || !Token::Match(var->typeEndToken(), "iterator|const_iterator|reverse_iterator|const_reverse_iterator|auto"))
return false;
inconclusiveType = false;
if (var->typeEndToken()->str() == "auto")
return (var->nameToken()->valueType() && var->nameToken()->valueType()->type == ValueType::Type::ITERATOR);
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) {
return false;
} else {
inconclusiveType = true; // heuristics only
}
}
return true;
}
static std::string getContainerName(const Token *containerToken)
{
if (!containerToken)
return std::string();
std::string ret(containerToken->str());
for (const Token *nametok = containerToken; nametok; nametok = nametok->tokAt(-2)) {
if (!Token::Match(nametok->tokAt(-2), "%name% ."))
break;
ret = nametok->strAt(-2) + '.' + ret;
}
return ret;
}
enum OperandPosition {
Left,
Right
};
static const Token* findIteratorContainer(const Token* start, const Token* end, unsigned int id)
{
const Token* containerToken = nullptr;
for (const Token* tok = start; tok != end; tok = tok->next()) {
if (Token::Match(tok, "%varid% = %name% . %name% (", id)) {
// Iterator is assigned to value
if (tok->tokAt(5)->valueType() && tok->tokAt(5)->valueType()->type == ValueType::Type::ITERATOR) {
containerToken = tok->tokAt(2);
}
} else if (Token::Match(tok, "%varid% = %name% (", id)) {
// Prevent FP: iterator is assigned to something
// TODO: Fix it in future
containerToken = nullptr;
}
}
return containerToken;
}
void CheckStl::iterators()
{
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
// Filling map of iterators id and their scope begin
std::map<unsigned int, const Token*> iteratorScopeBeginInfo;
for (const Variable* var : symbolDatabase->variableList()) {
bool inconclusiveType=false;
if (!isIterator(var, inconclusiveType))
continue;
const unsigned int iteratorId = var->declarationId();
if (iteratorId != 0)
iteratorScopeBeginInfo[iteratorId] = var->nameToken();
}
// Storage to save found comparison problems to avoid duplicate error messages
std::set<const Token*> foundOperatorErrors;
for (const Variable* var : symbolDatabase->variableList()) {
bool inconclusiveType=false;
if (!isIterator(var, inconclusiveType))
continue;
if (inconclusiveType && !mSettings->inconclusive)
continue;
const unsigned int iteratorId = var->declarationId();
// the validIterator flag says if the iterator has a valid value or not
bool validIterator = Token::Match(var->nameToken()->next(), "[(=:{]");
const Scope* invalidationScope = nullptr;
// The container this iterator can be used with
const Token* containerToken = nullptr;
const Scope* containerAssignScope = nullptr;
// When "validatingToken" is reached the validIterator is set to true
const Token* validatingToken = nullptr;
const Token* eraseToken = nullptr;
// 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()->bodyEnd; tok2 = tok2->next()) {
if (invalidationScope && tok2 == invalidationScope->bodyEnd)
validIterator = true; // Assume that the iterator becomes valid again
if (containerAssignScope && tok2 == containerAssignScope->bodyEnd)
containerToken = nullptr; // We don't know which containers might be used with the iterator
if (tok2 == validatingToken) {
validIterator = true;
eraseToken = nullptr;
invalidationScope = nullptr;
}
// Is comparison expression?
// Check whether iterator compared against different container or iterator of different container?
if (tok2->isComparisonOp() && tok2->astOperand1() && tok2->astOperand2() &&
(foundOperatorErrors.find(tok2) == foundOperatorErrors.end()) &&
compareIteratorAgainstDifferentContainer(tok2, containerToken, iteratorId, iteratorScopeBeginInfo)) {
foundOperatorErrors.insert(tok2);
}
// 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 (containerToken && tok2->varId() != containerToken->varId()) {
// 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;
// inserting iterator range..
if (tok2->strAt(2) == "insert") {
const Token *par2 = itTok->nextArgument();
if (!par2 || par2->nextArgument())
continue;
while (par2->str() != ")") {
if (par2->varId() == containerToken->varId())
break;
bool inconclusiveType2=false;
if (isIterator(par2->variable(), inconclusiveType2))
break; // TODO: check if iterator points at same container
if (par2->str() == "(")
par2 = par2->link();
par2 = par2->next();
}
if (par2->str() != ")")
continue;
}
// Show error message, mismatching iterator is used.
iteratorsError(tok2, getContainerName(containerToken), getContainerName(tok2));
}
// invalidate the iterator if it is erased
else if (tok2->strAt(2) == "erase" && (tok2->strAt(4) != "*" || (containerToken && tok2->varId() == containerToken->varId()))) {
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 = skipMembers(tok2->tokAt(2))->linkAt(1);
tok2 = validatingToken->link();
}
// Reassign the iterator
else if (Token::Match(tok2, "%varid% = %name% .", iteratorId) &&
Token::Match(skipMembers(tok2->tokAt(2)), "begin|rbegin|cbegin|crbegin|find (")) {
validatingToken = skipMembers(tok2->tokAt(2))->linkAt(1);
containerToken = skipMembers(tok2->tokAt(2))->tokAt(-2);
if (containerToken->varId() == 0 || Token::simpleMatch(validatingToken, ") ."))
containerToken = nullptr;
containerAssignScope = tok2->scope();
// skip ahead
tok2 = validatingToken->link();
}
// Reassign the iterator
else if (Token::Match(tok2, "%varid% =", iteratorId)) {
break;
}
// 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), inconclusiveType);
tok2 = tok2->next();
} else if (!validIterator && Token::Match(tok2, "%varid% . %name%", iteratorId)) {
dereferenceErasedError(eraseToken, tok2, tok2->str(), inconclusiveType);
tok2 = tok2->tokAt(2);
}
// bailout handling. Assume that the iterator becomes valid if we see return/break.
// TODO: better handling
else if (tok2->scope() == invalidationScope && Token::Match(tok2, "return|break|continue")) {
validatingToken = Token::findsimplematch(tok2->next(), ";");
}
// bailout handling. Assume that the iterator becomes valid if we see else.
// TODO: better handling
else if (tok2->str() == "else") {
validIterator = true;
}
}
}
}
bool CheckStl::compareIteratorAgainstDifferentContainer(const Token* operatorTok, const Token* containerTok, const unsigned int iteratorId, const std::map<unsigned int, const Token*>& iteratorScopeBeginInfo)
{
if (!containerTok)
return false;
const Token *otherOperand = nullptr;
OperandPosition operandPosition;
if (operatorTok->astOperand1()->varId() == iteratorId) {
otherOperand = operatorTok->astOperand2();
operandPosition = OperandPosition::Right;
} else if (operatorTok->astOperand2()->varId() == iteratorId) {
otherOperand = operatorTok->astOperand1();
operandPosition = OperandPosition::Left;
}
if (!otherOperand)
return false;
const Token * const otherExprPart = otherOperand->tokAt(-3);
if (Token::Match(otherExprPart, "%name% . end|rend|cend|crend ( )") && otherExprPart->varId() != containerTok->varId()) {
const std::string& firstContainerName = getContainerName(containerTok);
const std::string& secondContainerName = getContainerName(otherExprPart);
if (firstContainerName != secondContainerName) {
if (operandPosition == OperandPosition::Right)
iteratorsError(operatorTok, containerTok, firstContainerName, secondContainerName);
else
iteratorsError(operatorTok, containerTok, secondContainerName, firstContainerName);
} else {
iteratorsError(operatorTok, containerTok, firstContainerName);
}
return true;
} else {
const unsigned int otherId = otherOperand->varId();
auto it = iteratorScopeBeginInfo.find(otherId);
if (it != iteratorScopeBeginInfo.end()) {
const Token* otherContainerToken = findIteratorContainer(it->second, operatorTok->astOperand1(), otherId);
if (otherContainerToken && otherContainerToken->varId() != containerTok->varId()) {
const std::string& firstContainerName = getContainerName(containerTok);
const std::string& secondContainerName = getContainerName(otherContainerToken);
if (firstContainerName != secondContainerName) {
if (operandPosition == OperandPosition::Right)
iteratorsCmpError(operatorTok, containerTok, otherContainerToken, firstContainerName, secondContainerName);
else
iteratorsCmpError(operatorTok, containerTok, otherContainerToken, secondContainerName, firstContainerName);
} else {
iteratorsCmpError(operatorTok, containerTok, otherContainerToken, firstContainerName);
}
return true;
}
}
}
return false;
}
// Error message for bad iterator usage..
void CheckStl::mismatchingContainersError(const Token *tok)
{
reportError(tok, Severity::error, "mismatchingContainers", "Iterators of different containers are used together.", CWE664, false);
}
void CheckStl::mismatchingContainerExpressionError(const Token *tok1, const Token *tok2)
{
const std::string expr1(tok1 ? tok1->expressionString() : std::string("v1"));
const std::string expr2(tok2 ? tok2->expressionString() : std::string("v2"));
reportError(tok1, Severity::warning, "mismatchingContainerExpression",
"Iterators to containers from different expressions '" +
expr1 + "' and '" + expr2 + "' are used together.", CWE664, false);
}
void CheckStl::sameIteratorExpressionError(const Token *tok)
{
reportError(tok, Severity::style, "sameIteratorExpression", "Same iterators expression are used for algorithm.", CWE664, false);
}
static const std::set<std::string> algorithm2 = { // func(begin1, end1
"binary_search", "copy", "copy_if", "equal_range"
, "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", "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"
, "shuffle", "sort", "sort_heap", "stable_partition", "stable_sort", "swap_ranges", "transform", "unique"
, "unique_copy", "upper_bound", "string", "wstring", "u16string", "u32string"
};
static const std::set<std::string> algorithm22 = { // func(begin1, end1, begin2, end2
"includes", "lexicographical_compare", "merge", "partial_sort_copy"
, "set_difference", "set_intersection", "set_symmetric_difference", "set_union"
};
static const std::set<std::string> algorithm1x1 = { // func(begin1, x, end1
"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;
static const Variable *getContainer(const Token *argtok)
{
while (argtok && argtok->astOperand1())
argtok = argtok->astOperand1();
if (!Token::Match(argtok, "%var% . begin|end|rbegin|rend ( )")) // TODO: use Library yield
return nullptr;
const Variable *var = argtok->variable();
if (var && Token::simpleMatch(var->typeStartToken(), "std ::"))
return var;
return nullptr;
}
static const Token * getIteratorExpression(const Token * tok)
{
if (!tok)
return nullptr;
if (tok->isUnaryOp("*"))
return nullptr;
if (!tok->isName()) {
const Token *iter1 = getIteratorExpression(tok->astOperand1());
if (iter1)
return iter1;
if (tok->str() == "(")
return nullptr;
const Token *iter2 = getIteratorExpression(tok->astOperand2());
if (iter2)
return iter2;
} else if (Token::Match(tok, "begin|cbegin|rbegin|crbegin|end|cend|rend|crend (")) {
if (Token::Match(tok->previous(), ". %name% ( ) !!."))
return tok->previous()->astOperand1();
if (!Token::simpleMatch(tok->previous(), ".") && Token::Match(tok, "%name% ( !!)") && !Token::simpleMatch(tok->linkAt(1), ") ."))
return tok->next()->astOperand2();
}
return nullptr;
}
void CheckStl::mismatchingContainers()
{
// Check if different containers are used in various calls of standard functions
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
for (const Scope * scope : symbolDatabase->functionScopes) {
for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
if (Token::Match(tok, "%comp%|-")) {
const Token * iter1 = getIteratorExpression(tok->astOperand1());
const Token * iter2 = getIteratorExpression(tok->astOperand2());
if (iter1 && iter2 && !isSameExpression(true, false, iter1, iter2, mSettings->library, false, false)) {
mismatchingContainerExpressionError(iter1, iter2);
continue;
}
}
if (!Token::Match(tok, "%name% ( !!)"))
continue;
const Token * const ftok = tok;
const Token * firstArg = nullptr;
const std::vector<const Token *> args = getArguments(ftok);
if (args.size() < 2)
continue;
std::map<const Variable *, unsigned int> containerNr;
for (unsigned int argnr = 1; argnr <= args.size(); ++argnr) {
const Library::ArgumentChecks::IteratorInfo *i = mSettings->library.getArgIteratorInfo(ftok, argnr);
if (!i)
continue;
const Token * const argTok = args[argnr - 1];
if (i->first) {
firstArg = argTok;
}
if (i->last && firstArg && argTok && isSameExpression(true, false, firstArg, argTok, mSettings->library, false, false)) {
sameIteratorExpressionError(firstArg);
}
const Variable *c = getContainer(argTok);
if (c) {
std::map<const Variable *, unsigned int>::const_iterator it = containerNr.find(c);
if (it == containerNr.end()) {
for (it = containerNr.begin(); it != containerNr.end(); ++it) {
if (it->second == i->container) {
mismatchingContainersError(argTok);
break;
}
}
containerNr[c] = i->container;
} else if (it->second != i->container) {
mismatchingContainersError(argTok);
}
} else {
if (i->last && firstArg && argTok) {
const Token * iter1 = getIteratorExpression(firstArg);
const Token * iter2 = getIteratorExpression(argTok);
if (iter1 && iter2 && !isSameExpression(true, false, iter1, iter2, mSettings->library, false, false)) {
mismatchingContainerExpressionError(iter1, iter2);
}
}
}
}
const int ret = mSettings->library.returnValueContainer(ftok);
if (ret != -1 && Token::Match(ftok->next()->astParent(), "==|!=")) {
const Token *parent = ftok->next()->astParent();
const Token *other = (parent->astOperand1() == ftok->next()) ? parent->astOperand2() : parent->astOperand1();
const Variable *c = getContainer(other);
if (c) {
const std::map<const Variable *, unsigned int>::const_iterator it = containerNr.find(c);
if (it == containerNr.end() || it->second != ret)
mismatchingContainersError(other);
}
}
}
}
for (const Variable *var : symbolDatabase->variableList()) {
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 = mTokenizer->getSymbolDatabase();
// Scan through all scopes..
for (const Scope &scope : symbolDatabase->scopeList) {
const Token* tok = scope.classDef;
// only interested in conditions
if ((scope.type != Scope::eFor && scope.type != Scope::eWhile && scope.type != Scope::eIf && scope.type != Scope::eDo) || !tok)
continue;
if (scope.type == Scope::eFor)
tok = Token::findsimplematch(tok->tokAt(2), ";");
else if (scope.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%"))
continue;
// Is it a vector?
const Variable *var = tok->tokAt(2)->variable();
if (!var)
continue;
const Library::Container* container = mSettings->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 = scope.bodyStart; tok3 && tok3 != scope.bodyEnd; 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)) {
const Library::Container::Yield yield = container->getYield(tok3->strAt(1));
if (yield == Library::Container::AT_INDEX)
stlOutOfBoundsError(tok3, tok3->strAt(3), var->name(), true);
}
}
}
}
}
void CheckStl::stlOutOfBoundsError(const Token *tok, const std::string &num, const std::string &var, bool at)
{
if (at)
reportError(tok, Severity::error, "stlOutOfBounds", "$symbol:" + var + "\nWhen " + num + "==$symbol.size(), $symbol.at(" + num + ") is out of bounds.", CWE788, false);
else
reportError(tok, Severity::error, "stlOutOfBounds", "$symbol:" + var + "\nWhen " + num + "==$symbol.size(), $symbol[" + num + "] is out of bounds.", CWE788, false);
}
void CheckStl::negativeIndex()
{
// Negative index is out of bounds..
const SymbolDatabase* const symbolDatabase = mTokenizer->getSymbolDatabase();
for (const Scope * scope : symbolDatabase->functionScopes) {
for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
if (!Token::Match(tok, "%var% [") || WRONG_DATA(!tok->next()->astOperand2(), tok))
continue;
const Variable * const var = tok->variable();
if (!var || tok == var->nameToken())
continue;
const Library::Container * const container = mSettings->library.detectContainer(var->typeStartToken());
if (!container || !container->arrayLike_indexOp)
continue;
const ValueFlow::Value *index = tok->next()->astOperand2()->getValueLE(-1, mSettings);
if (!index)
continue;
negativeIndexError(tok, *index);
}
}
}
void CheckStl::negativeIndexError(const Token *tok, const ValueFlow::Value &index)
{
const ErrorPath errorPath = getErrorPath(tok, &index, "Negative array index");
std::ostringstream errmsg;
if (index.condition)
errmsg << ValueFlow::eitherTheConditionIsRedundant(index.condition)
<< ", otherwise there is negative array index " << index.intvalue << ".";
else
errmsg << "Array index " << index.intvalue << " is out of bounds.";
reportError(errorPath, index.errorSeverity() ? Severity::error : Severity::warning, "negativeContainerIndex", errmsg.str(), CWE786, index.isInconclusive());
}
void CheckStl::erase()
{
const SymbolDatabase* const symbolDatabase = mTokenizer->getSymbolDatabase();
for (const Scope &scope : symbolDatabase->scopeList) {
if (scope.type == Scope::eFor && Token::simpleMatch(scope.classDef, "for (")) {
const Token *tok = scope.classDef->linkAt(1);
if (!Token::Match(tok->tokAt(-3), "; ++| %var% ++| ) {"))
continue;
tok = tok->previous();
if (!tok->isName())
tok = tok->previous();
eraseCheckLoopVar(scope, tok->variable());
} else if (scope.type == Scope::eWhile && Token::Match(scope.classDef, "while ( %var% !=")) {
eraseCheckLoopVar(scope, scope.classDef->tokAt(2)->variable());
}
}
}
void CheckStl::eraseCheckLoopVar(const Scope &scope, const Variable *var)
{
bool inconclusiveType=false;
if (!isIterator(var, inconclusiveType))
return;
for (const Token *tok = scope.bodyStart; tok != scope.bodyEnd; 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.bodyEnd; 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(), inconclusiveType);
break;
}
if (indentlevel == 0U && Token::Match(tok2, "break|return|goto"))
break;
}
if (tok2 == scope.bodyEnd)
dereferenceErasedError(tok, scope.classDef, var->nameToken()->str(), inconclusiveType);
}
}
void CheckStl::pushback()
{
// Pointer can become invalid after push_back, push_front, reserve or resize..
const SymbolDatabase* const symbolDatabase = mTokenizer->getSymbolDatabase();
for (const Scope * scope : symbolDatabase->functionScopes) {
for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
if (Token::Match(tok, "%var% = & %var% [")) {
// Skip it directly if it is a pointer or an array
const Token* containerTok = tok->tokAt(3);
if (containerTok->variable() && containerTok->variable()->isArrayOrPointer())
continue;
// Variable id for pointer
const unsigned int pointerId(tok->varId());
bool invalidPointer = false;
const Token* function = nullptr;
const Token* end2 = tok->scope()->bodyEnd;
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", containerTok->varId())) {
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 (const Variable* var : symbolDatabase->variableList()) {
// Check that its an iterator
if (!var || !var->isLocal() || !Token::Match(var->typeEndToken(), "iterator|const_iterator|reverse_iterator|const_reverse_iterator"))
continue;
const unsigned int iteratorId = var->declarationId();
// ... on std::vector
if (!Token::Match(var->typeStartToken(), "std| ::| vector <"))
continue;
// the variable id for the vector
unsigned int vectorid = 0;
const Token* validatingToken = nullptr;
std::string invalidIterator;
const Token* end2 = var->scope()->bodyEnd;
for (const Token *tok2 = var->nameToken(); tok2 != end2; tok2 = tok2->next()) {
if (validatingToken == tok2) {
invalidIterator.clear();
validatingToken = nullptr;
}
// 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 = nullptr;
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.clear();
}
// 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",
"$symbol:" + func + "\n"
"$symbol:" + iterator_name + "\n"
"After " + func + "(), the iterator '" + iterator_name + "' may be invalid.", CWE664, false);
}
// Error message for bad iterator usage..
void CheckStl::invalidPointerError(const Token *tok, const std::string &func, const std::string &pointer_name)
{
reportError(tok, Severity::error, "invalidPointer",
"$symbol:" + func + "\n"
"$symbol:" + pointer_name + "\n"
"Invalid pointer '" + pointer_name + "' after " + func + "().", CWE664, false);
}
void CheckStl::stlBoundaries()
{
const SymbolDatabase* const symbolDatabase = mTokenizer->getSymbolDatabase();
for (const Variable* var : symbolDatabase->variableList()) {
if (!var || !var->scope() || !var->scope()->isExecutable())
continue;
const Library::Container* container = mSettings->library.detectContainer(var->typeStartToken(), true);
if (!container || container->opLessAllowed)
continue;
const Token* const end = var->scope()->bodyEnd;
for (const Token *tok = var->nameToken(); tok != end; tok = tok->next()) {
if (Token::Match(tok, "!!* %varid% <", var->declarationId())) {
stlBoundariesError(tok);
} else if (Token::Match(tok, "> %varid% !!.", var->declarationId())) {
stlBoundariesError(tok);
}
}
}
}
// Error message for bad boundary usage..
void CheckStl::stlBoundariesError(const Token *tok)
{
reportError(tok, Severity::error, "stlBoundaries",
"Dangerous comparison using operator< on iterator.\n"
"Iterator 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.", CWE664, false);
}
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 = mSettings->isEnabled(Settings::WARNING);
const bool printPerformance = mSettings->isEnabled(Settings::PERFORMANCE);
if (!printWarning && !printPerformance)
return;
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
for (const Scope &scope : symbolDatabase->scopeList) {
if ((scope.type != Scope::eIf && scope.type != Scope::eWhile) || !scope.classDef)
continue;
for (const Token *tok = scope.classDef->next(); tok->str() != "{"; tok = tok->next()) {
const Token* funcTok = nullptr;
const Library::Container* container = nullptr;
if (Token::Match(tok, "%name% ("))
tok = tok->linkAt(1);
else if (tok->variable() && Token::Match(tok, "%var% . %name% (")) {
container = mSettings->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 = mSettings->library.detectContainer(tok->variable()->typeStartToken());
else { // Container of container - find the inner container
container = mSettings->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 = mSettings->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->getYield(funcTok->str()) == Library::Container::ITERATOR)
if_findError(tok, false);
else if (printPerformance && container->stdStringLike && funcTok->str() == "find")
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.", CWE597, false);
else
reportError(tok, Severity::warning, "stlIfFind", "Suspicious condition. The result of find() is an iterator, but it is not properly checked.", CWE398, false);
}
/**
* 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 (!mSettings->isEnabled(Settings::PERFORMANCE))
return;
if (mSettings->standards.cpp == Standards::CPP11)
return;
const SymbolDatabase* const symbolDatabase = mTokenizer->getSymbolDatabase();
for (const Scope * scope : symbolDatabase->functionScopes) {
for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
if (Token::Match(tok, "%var% . size ( )") ||
Token::Match(tok, "%name% . %var% . size ( )")) {
// get the variable
const Token *varTok = tok;
if (tok->strAt(2) != "size")
varTok = varTok->tokAt(2);
const Token* const end = varTok->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(varTok)) {
sizeError(varTok);
continue;
}
}
// 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(varTok))
sizeError(varTok);
}
// 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(varTok))
sizeError(varTok);
}
}
}
}
}
void CheckStl::sizeError(const Token *tok)
{
const std::string varname = tok ? tok->str() : std::string("list");
reportError(tok, Severity::performance, "stlSize",
"$symbol:" + varname + "\n"
"Possible inefficient checking for '$symbol' emptiness.\n"
"Checking for '$symbol' emptiness might be inefficient. "
"Using $symbol.empty() instead of $symbol.size() can be faster. "
"$symbol.size() can take linear time but $symbol.empty() is "
"guaranteed to take constant time.", CWE398, false);
}
void CheckStl::redundantCondition()
{
if (!mSettings->isEnabled(Settings::STYLE))
return;
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
for (const Scope &scope : symbolDatabase->scopeList) {
if (scope.type != Scope::eIf)
continue;
const Token* tok = scope.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.", CWE398, false);
}
void CheckStl::missingComparison()
{
if (!mSettings->isEnabled(Settings::WARNING))
return;
const SymbolDatabase* const symbolDatabase = mTokenizer->getSymbolDatabase();
for (const Scope &scope : symbolDatabase->scopeList) {
if (scope.type != Scope::eFor || !scope.classDef)
continue;
for (const Token *tok2 = scope.classDef->tokAt(2); tok2 != scope.bodyStart; 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 = scope.bodyStart; tok3 != scope.bodyEnd; 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 = nullptr;
else if (tok3->str() == "break" || tok3->str() == "return")
incrementToken = nullptr;
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 = { incrementToken1,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(), CWE834, false);
}
static bool isLocal(const Token *tok)
{
const Variable *var = tok->variable();
return var && !var->isStatic() && var->isLocal();
}
namespace {
const std::set<std::string> stl_string_stream = {
"istringstream", "ostringstream", "stringstream", "wstringstream"
};
}
void CheckStl::string_c_str()
{
const bool printInconclusive = mSettings->inconclusive;
const bool printPerformance = mSettings->isEnabled(Settings::PERFORMANCE);
const SymbolDatabase* symbolDatabase = mTokenizer->getSymbolDatabase();
// Find all functions that take std::string as argument
std::multimap<std::string, unsigned int> c_strFuncParam;
if (printPerformance) {
for (const Scope &scope : symbolDatabase->scopeList) {
for (const Function &func : scope.functionList) {
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 Variable &var : func.argumentList) {
numpar++;
if (var.isStlStringType() && (!var.isReference() || var.isConst()))
c_strFuncParam.insert(std::make_pair(func.tokenDef->str(), numpar));
}
}
}
}
// Try to detect common problems when using string::c_str()
for (const Scope &scope : symbolDatabase->scopeList) {
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.bodyStart; tok && tok != scope.bodyEnd; tok = tok->next()) {
// Invalid usage..
if (Token::Match(tok, "throw %var% . c_str|data ( ) ;") && isLocal(tok->next()) &&
tok->next()->variable() && tok->next()->variable()->isStlStringType()) {
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
const 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 if (tok2)
tok2 = tok2->previous();
else
break;
if (tok2 && Token::Match(tok2->tokAt(-4), ". c_str|data ( )")) {
const Variable* var = tok2->tokAt(-5)->variable();
if (var && var->isStlStringType()) {
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 || (printPerformance && (returnType == stdString || returnType == stdStringConstRef))) && tok->str() == "return") {
bool err = false;
const Token* tok2 = tok->next();
if (Token::Match(tok2, "std :: string|wstring (") &&
Token::Match(tok2->linkAt(3), ") . c_str|data ( ) ;")) {
err = true;
} else if (Token::simpleMatch(tok2, "(") &&
Token::Match(tok2->link(), ") . c_str|data ( ) ;")) {
// Check for "+ localvar" or "+ std::string(" inside the bracket
bool is_implicit_std_string = printInconclusive;
const Token *search_end = tok2->link();
for (const Token *search_tok = tok2->next(); 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()->isStlStringType()) {
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)
err = true;
}
bool local = false;
bool ptrOrRef = false;
const Variable* lastVar = nullptr;
const Function* lastFunc = nullptr;
bool funcStr = false;
if (Token::Match(tok2, "%var% .")) {
local = isLocal(tok2);
bool refToNonLocal = false;
if (tok2->variable() && tok2->variable()->isReference()) {
const Token *refTok = tok2->variable()->nameToken();
refToNonLocal = true; // safe assumption is default to avoid FPs
if (Token::Match(refTok, "%var% = %var% .|;|["))
refToNonLocal = !isLocal(refTok->tokAt(2));
}
ptrOrRef = refToNonLocal || (tok2->variable() && tok2->variable()->isPointer());
}
while (tok2) {
if (Token::Match(tok2, "%var% .|::")) {
if (ptrOrRef)
local = false;
lastVar = tok2->variable();
tok2 = tok2->tokAt(2);
} else if (Token::Match(tok2, "%name% (") && Token::simpleMatch(tok2->linkAt(1), ") .")) {
lastFunc = tok2->function();
local = false;
funcStr = tok2->str() == "str";
tok2 = tok2->linkAt(1)->tokAt(2);
} else
break;
}
if (Token::Match(tok2, "c_str|data ( ) ;")) {
if ((local || returnType != charPtr) && lastVar && lastVar->isStlStringType())
err = true;
else if (funcStr && lastVar && lastVar->isStlType(stl_string_stream))
err = true;
else if (lastFunc && Token::Match(lastFunc->tokenDef->tokAt(-3), "std :: string|wstring"))
err = true;
}
if (err) {
if (returnType == charPtr)
string_c_strError(tok);
else
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.", CWE664, false);
}
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.", CWE704, false);
}
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(), CWE704, false);
}
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
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 = mSettings->library.allocId("malloc"); // allocation function, which are not compatible with auto_ptr
const bool printStyle = mSettings->isEnabled(Settings::STYLE);
for (const Token *tok = mTokenizer->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 && mSettings->library.alloc(tok3->next(), -1) == malloc) {
// malloc-like function allocated memory passed to the auto_ptr constructor -> error
autoPointerMallocError(tok2->next(), tok3->next()->str());
}
if (Token::Match(tok3, "( %var%")) {
const 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(mTokenizer->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) {
const 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))) {
const 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 && mSettings->library.alloc(tok->tokAt(2), -1) == malloc) {
// C library function like 'malloc' used together with auto pointer -> error
const 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 && mSettings->library.alloc(tok->tokAt(4), -1) == malloc) {
// C library function like 'malloc' used when resetting auto pointer -> error
const 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.",
CWE398, false);
}
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.", CWE664, false
);
}
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[]'.", CWE664, false
);
}
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 '$symbol'.";
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 '$symbol'), which must be deallocated by the appropriate C library function.";
reportError(tok, Severity::error, "useAutoPointerMalloc", "$symbol:" + allocFunction + '\n' + summary + '\n' + verbose, CWE762, false);
}
namespace {
const std::set<std::string> stl_containers_with_empty_and_clear = {
"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 = mSettings->isEnabled(Settings::PERFORMANCE);
const bool printWarning = mSettings->isEnabled(Settings::WARNING);
if (!printPerformance && !printWarning)
return;
const SymbolDatabase* symbolDatabase = mTokenizer->getSymbolDatabase();
for (const Scope * scope : symbolDatabase->functionScopes) {
for (const Token* tok = scope->bodyStart; tok != scope->bodyEnd; 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()) {
const Variable* var = tok->variable();
if (!var || !var->isStlType())
continue;
uselessCallsReturnValueError(tok->tokAt(4), tok->str(), tok->strAt(2));
} else if (printPerformance && Token::Match(tok, "%var% . swap ( %name% )") &&
tok->varId() == tok->tokAt(4)->varId()) {
const Variable* var = tok->variable();
if (!var || !var->isStlType())
continue;
uselessCallsSwapError(tok, tok->str());
} else if (printPerformance && Token::Match(tok, "%var% . substr (") &&
tok->variable() && tok->variable()->isStlStringType()) {
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->tokAt(4)->astParent() &&
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 << "$symbol:" << varname << '\n';
errmsg << "$symbol:" << function << '\n';
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(), CWE628, false);
}
void CheckStl::uselessCallsSwapError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::performance, "uselessCallsSwap",
"$symbol:" + varname + "\n"
"It is inefficient to swap a object with itself by calling '$symbol.swap($symbol)'\n"
"The 'swap()' function has no logical effect when given itself as parameter "
"($symbol.swap($symbol)). As it is currently the "
"code is inefficient. Is the object or the parameter wrong here?", CWE628, false);
}
void CheckStl::uselessCallsSubstrError(const Token *tok, bool empty)
{
if (empty)
reportError(tok, Severity::performance, "uselessCallsSubstr", "Ineffective call of function 'substr' because it returns an empty string.", CWE398, false);
else
reportError(tok, Severity::performance, "uselessCallsSubstr", "Ineffective call of function 'substr' because it returns a copy of the object. Use operator= instead.", CWE398, false);
}
void CheckStl::uselessCallsEmptyError(const Token *tok)
{
reportError(tok, Severity::warning, "uselessCallsEmpty", "Ineffective call of function 'empty()'. Did you intend to call 'clear()' instead?", CWE398, false);
}
void CheckStl::uselessCallsRemoveError(const Token *tok, const std::string& function)
{
reportError(tok, Severity::warning, "uselessCallsRemove",
"$symbol:" + function + "\n"
"Return value of std::$symbol() ignored. Elements remain in container.\n"
"The return value of std::$symbol() 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.", CWE762, false);
}
// Check for iterators being dereferenced before being checked for validity.
// E.g. if (*i && i != str.end()) { }
void CheckStl::checkDereferenceInvalidIterator()
{
if (!mSettings->isEnabled(Settings::WARNING))
return;
// Iterate over "if", "while", and "for" conditions where there may
// be an iterator that is dereferenced before being checked for validity.
for (const Scope &scope : mTokenizer->getSymbolDatabase()->scopeList) {
if (!(scope.type == Scope::eIf || scope.type == Scope::eDo || scope.type == Scope::eWhile || scope.type == Scope::eFor))
continue;
const Token* const tok = scope.classDef;
const Token* startOfCondition = tok->next();
if (scope.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 (scope.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) != nullptr;
const bool isAndExpression =
Token::findsimplematch(startOfCondition, "&&", endOfCondition) != nullptr;
// Look for a check of the validity of an iterator
const Token* validityCheckTok = nullptr;
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",
"$symbol:" + iterName + "\n"
"Possible dereference of an invalid iterator: $symbol\n"
"Possible dereference of an invalid iterator: $symbol. Make sure to check that the iterator is valid before dereferencing it - not after.", CWE825, false);
}
void CheckStl::readingEmptyStlContainer2()
{
for (const Scope *function : mTokenizer->getSymbolDatabase()->functionScopes) {
for (const Token *tok = function->bodyStart; tok != function->bodyEnd; tok = tok->next()) {
if (!tok->isName() || !tok->valueType())
continue;
const Library::Container *container = tok->valueType()->container;
if (!container)
continue;
const ValueFlow::Value *value = tok->getContainerSizeValue(0);
if (!value)
continue;
if (value->isInconclusive() && !mSettings->inconclusive)
continue;
if (!value->errorSeverity() && !mSettings->isEnabled(Settings::WARNING))
continue;
if (Token::Match(tok, "%name% . %name% (")) {
if (container->getYield(tok->strAt(2)) == Library::Container::Yield::ITEM)
readingEmptyStlContainerError(tok,value);
}
}
}
}
void CheckStl::readingEmptyStlContainerError(const Token *tok, const ValueFlow::Value *value)
{
const std::string varname = tok ? tok->str() : std::string("var");
std::string errmsg;
if (value && value->condition)
errmsg = "Reading from container '$symbol'. " + ValueFlow::eitherTheConditionIsRedundant(value->condition) + " or '$symbol' can be empty.";
else
errmsg = "Reading from empty STL container '$symbol'";
const ErrorPath errorPath = getErrorPath(tok, value, "Reading from empty container");
reportError(errorPath, value ? (value->errorSeverity() ? Severity::error : Severity::warning) : Severity::style, "reademptycontainer", "$symbol:" + varname +"\n" + errmsg, CWE398, !value);
}
void CheckStl::useStlAlgorithmError(const Token *tok, const std::string &algoName)
{
reportError(tok, Severity::style, "useStlAlgorithm",
"Consider using " + algoName + " algorithm instead of a raw loop.", CWE398, false);
}
static bool isEarlyExit(const Token *start)
{
if (start->str() != "{")
return false;
const Token *endToken = start->link();
const Token *tok = Token::findmatch(start, "return|throw|break", endToken);
if (!tok)
return false;
const Token *endStatement = Token::findsimplematch(tok, "; }", endToken);
if (!endStatement)
return false;
if (endStatement->next() != endToken)
return false;
return true;
}
static const Token *singleStatement(const Token *start)
{
if (start->str() != "{")
return nullptr;
const Token *endToken = start->link();
const Token *endStatement = Token::findsimplematch(start->next(), ";");
if (!Token::simpleMatch(endStatement, "; }"))
return nullptr;
if (endStatement->next() != endToken)
return nullptr;
return endStatement;
}
static const Token *singleAssignInScope(const Token *start, unsigned int varid, bool &input)
{
const Token *endStatement = singleStatement(start);
if (!endStatement)
return nullptr;
if (!Token::Match(start->next(), "%var% %assign%"))
return nullptr;
const Token *assignTok = start->tokAt(2);
if (isVariableChanged(assignTok->next(), endStatement, assignTok->astOperand1()->varId(), false, nullptr, true))
return nullptr;
if (isVariableChanged(assignTok->next(), endStatement, varid, false, nullptr, true))
return nullptr;
input = Token::findmatch(assignTok->next(), "%varid%", endStatement, varid);
return assignTok;
}
static const Token *singleMemberCallInScope(const Token *start, unsigned int varid, bool &input)
{
if (start->str() != "{")
return nullptr;
const Token *endToken = start->link();
if (!Token::Match(start->next(), "%var% . %name% ("))
return nullptr;
if (!Token::simpleMatch(start->linkAt(4), ") ; }"))
return nullptr;
const Token *endStatement = start->linkAt(4)->next();
if (endStatement->next() != endToken)
return nullptr;
const Token *dotTok = start->tokAt(2);
if (!Token::findmatch(dotTok->tokAt(2), "%varid%", endStatement, varid))
return nullptr;
input = Token::Match(start->next(), "%var% . %name% ( %varid% )", varid);
if (isVariableChanged(dotTok->next(), endStatement, dotTok->astOperand1()->varId(), false, nullptr, true))
return nullptr;
return dotTok;
}
static const Token *singleIncrementInScope(const Token *start, unsigned int varid, bool &input)
{
if (start->str() != "{")
return nullptr;
const Token *varTok = nullptr;
if (Token::Match(start->next(), "++ %var% ; }"))
varTok = start->tokAt(2);
else if (Token::Match(start->next(), "%var% ++ ; }"))
varTok = start->tokAt(1);
if (!varTok)
return nullptr;
input = varTok->varId() == varid;
return varTok;
}
static const Token *singleConditionalInScope(const Token *start, unsigned int varid)
{
if (start->str() != "{")
return nullptr;
const Token *endToken = start->link();
if (!Token::simpleMatch(start->next(), "if ("))
return nullptr;
if (!Token::simpleMatch(start->linkAt(2), ") {"))
return nullptr;
const Token *bodyTok = start->linkAt(2)->next();
const Token *endBodyTok = bodyTok->link();
if (!Token::simpleMatch(endBodyTok, "} }"))
return nullptr;
if (endBodyTok->next() != endToken)
return nullptr;
if (!Token::findmatch(start, "%varid%", bodyTok, varid))
return nullptr;
if (isVariableChanged(start, bodyTok, varid, false, nullptr, true))
return nullptr;
return bodyTok;
}
static bool addByOne(const Token *tok, unsigned int varid)
{
if (Token::Match(tok, "+= %any% ;") &&
tok->tokAt(1)->hasKnownIntValue() &&
tok->tokAt(1)->getValue(1)) {
return true;
}
if (Token::Match(tok, "= %varid% + %any% ;", varid) &&
tok->tokAt(3)->hasKnownIntValue() &&
tok->tokAt(3)->getValue(1)) {
return true;
}
return false;
}
static bool accumulateBoolLiteral(const Token *tok, unsigned int varid)
{
// TODO: Missing %oreq%
if (Token::Match(tok, "=|&= %bool% ;") &&
tok->tokAt(1)->hasKnownIntValue()) {
return true;
}
if (Token::Match(tok, "= %varid% %oror%|%or%|&&|& %bool% ;", varid) &&
tok->tokAt(3)->hasKnownIntValue()) {
return true;
}
return false;
}
static bool accumulateBool(const Token *tok, unsigned int varid)
{
// TODO: Missing %oreq%
if (Token::simpleMatch(tok, "&=")) {
return true;
}
if (Token::Match(tok, "= %varid% %oror%|%or%|&&|&", varid)) {
return true;
}
return false;
}
static bool hasVarIds(const Token *tok, unsigned int var1, unsigned int var2)
{
if (tok->astOperand1()->varId() == tok->astOperand2()->varId())
return false;
if (tok->astOperand1()->varId() == var1 || tok->astOperand1()->varId() == var2) {
if (tok->astOperand2()->varId() == var1 || tok->astOperand2()->varId() == var2) {
return true;
}
}
return false;
}
static std::string flipMinMax(const std::string &algo)
{
if (algo == "std::max_element")
return "std::min_element";
if (algo == "std::min_element")
return "std::max_element";
return algo;
}
static std::string minmaxCompare(const Token *condTok, unsigned int loopVar, unsigned int assignVar, bool invert = false)
{
if (!Token::Match(condTok, "<|<=|>=|>"))
return "std::accumulate";
if (!hasVarIds(condTok, loopVar, assignVar))
return "std::accumulate";
std::string algo = "std::max_element";
if (Token::Match(condTok, "<|<="))
algo = "std::min_element";
if (condTok->astOperand1()->varId() == assignVar)
algo = flipMinMax(algo);
if (invert)
algo = flipMinMax(algo);
return algo;
}
void CheckStl::useStlAlgorithm()
{
if (!mSettings->isEnabled(Settings::STYLE))
return;
for (const Scope *function : mTokenizer->getSymbolDatabase()->functionScopes) {
for (const Token *tok = function->bodyStart; tok != function->bodyEnd; tok = tok->next()) {
// Parse range-based for loop
if (!Token::simpleMatch(tok, "for ("))
continue;
if (!Token::simpleMatch(tok->next()->link(), ") {"))
continue;
const Token *bodyTok = tok->next()->link()->next();
const Token *splitTok = tok->next()->astOperand2();
if (!Token::simpleMatch(splitTok, ":"))
continue;
const Token *loopVar = splitTok->previous();
if (!Token::Match(loopVar, "%var%"))
continue;
// Check for single assignment
bool useLoopVarInAssign;
const Token *assignTok = singleAssignInScope(bodyTok, loopVar->varId(), useLoopVarInAssign);
if (assignTok) {
unsigned int assignVarId = assignTok->astOperand1()->varId();
std::string algo;
if (assignVarId == loopVar->varId()) {
if (useLoopVarInAssign)
algo = "std::transform";
else if (Token::Match(assignTok->next(), "%var%|%bool%|%num%|%char% ;"))
algo = "std::fill";
else if (Token::Match(assignTok->next(), "%name% ( )"))
algo = "std::generate";
else
algo = "std::fill or std::generate";
} else {
if (addByOne(assignTok, assignVarId))
algo = "std::distance";
else if (accumulateBool(assignTok, assignVarId))
algo = "std::any_of, std::all_of, std::none_of, or std::accumulate";
else if (Token::Match(assignTok, "= %var% <|<=|>=|> %var% ? %var% : %var%") && hasVarIds(assignTok->tokAt(6), loopVar->varId(), assignVarId))
algo = minmaxCompare(assignTok->tokAt(2), loopVar->varId(), assignVarId, assignTok->tokAt(5)->varId() == assignVarId);
else
algo = "std::accumulate";
}
useStlAlgorithmError(assignTok, algo);
continue;
}
// Check for container calls
bool useLoopVarInMemCall;
const Token *memberAccessTok = singleMemberCallInScope(bodyTok, loopVar->varId(), useLoopVarInMemCall);
if (memberAccessTok) {
const Token *memberCallTok = memberAccessTok->astOperand2();
const unsigned int contVarId = memberAccessTok->astOperand1()->varId();
if (contVarId == loopVar->varId())
continue;
if (memberCallTok->str() == "push_back" ||
memberCallTok->str() == "push_front" ||
memberCallTok->str() == "emplace_back") {
std::string algo;
if (useLoopVarInMemCall)
algo = "std::copy";
else
algo = "std::transform";
useStlAlgorithmError(memberCallTok, algo);
}
continue;
}
// Check for increment in loop
bool useLoopVarInIncrement;
const Token *incrementTok = singleIncrementInScope(bodyTok, loopVar->varId(), useLoopVarInIncrement);
if (incrementTok) {
std::string algo;
if (useLoopVarInIncrement)
algo = "std::transform";
else
algo = "std::distance";
useStlAlgorithmError(incrementTok, algo);
continue;
}
// Check for conditionals
const Token *condBodyTok = singleConditionalInScope(bodyTok, loopVar->varId());
if (condBodyTok) {
// Check for single assign
assignTok = singleAssignInScope(condBodyTok, loopVar->varId(), useLoopVarInAssign);
if (assignTok) {
const unsigned int assignVarId = assignTok->astOperand1()->varId();
std::string algo;
if (assignVarId == loopVar->varId()) {
if (useLoopVarInAssign)
algo = "std::transform";
else
algo = "std::replace_if";
} else {
if (addByOne(assignTok, assignVarId))
algo = "std::count_if";
else if (accumulateBoolLiteral(assignTok, assignVarId))
algo = "std::any_of, std::all_of, std::none_of, or std::accumulate";
else
algo = "std::accumulate";
}
useStlAlgorithmError(assignTok, algo);
continue;
}
// Check for container call
memberAccessTok = singleMemberCallInScope(condBodyTok, loopVar->varId(), useLoopVarInMemCall);
if (memberAccessTok) {
const Token *memberCallTok = memberAccessTok->astOperand2();
const unsigned int contVarId = memberAccessTok->astOperand1()->varId();
if (contVarId == loopVar->varId())
continue;
if (memberCallTok->str() == "push_back" ||
memberCallTok->str() == "push_front" ||
memberCallTok->str() == "emplace_back") {
if (useLoopVarInMemCall)
useStlAlgorithmError(memberAccessTok, "std::copy_if");
// There is no transform_if to suggest
}
continue;
}
// Check for increment in loop
incrementTok = singleIncrementInScope(condBodyTok, loopVar->varId(), useLoopVarInIncrement);
if (incrementTok) {
std::string algo;
if (useLoopVarInIncrement)
algo = "std::transform";
else
algo = "std::count_if";
useStlAlgorithmError(incrementTok, algo);
continue;
}
// Check early return
if (isEarlyExit(condBodyTok)) {
const Token *loopVar2 = Token::findmatch(condBodyTok, "%varid%", condBodyTok->link(), loopVar->varId());
std::string algo;
if (loopVar2)
algo = "std::find_if";
else
algo = "std::any_of";
useStlAlgorithmError(condBodyTok, algo);
continue;
}
}
}
}
}