cppcheck/lib/checkleakautovar.cpp

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/*
* Cppcheck - A tool for static C/C++ code analysis
2019-02-09 07:24:06 +01:00
* Copyright (C) 2007-2019 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/>.
*/
//---------------------------------------------------------------------------
// Leaks when using auto variables
//---------------------------------------------------------------------------
#include "checkleakautovar.h"
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#include "astutils.h"
#include "checkmemoryleak.h" // <- CheckMemoryLeak::memoryLeak
#include "checknullpointer.h" // <- CheckNullPointer::isPointerDeRef
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#include "errorlogger.h"
#include "mathlib.h"
#include "settings.h"
#include "symboldatabase.h"
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#include "token.h"
#include "tokenize.h"
#include "valueflow.h"
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#include <cstddef>
#include <iostream>
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#include <list>
#include <stack>
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#include <utility>
//---------------------------------------------------------------------------
// Register this check class (by creating a static instance of it)
namespace {
CheckLeakAutoVar instance;
}
static const CWE CWE672(672U);
static const CWE CWE415(415U);
// Hardcoded allocation types (not from library)
static const int NEW_ARRAY = -2;
static const int NEW = -1;
//---------------------------------------------------------------------------
void VarInfo::print()
{
std::cout << "size=" << alloctype.size() << std::endl;
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for (std::map<unsigned int, AllocInfo>::const_iterator it = alloctype.begin(); it != alloctype.end(); ++it) {
std::string strusage;
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const std::map<unsigned int, std::string>::const_iterator use =
possibleUsage.find(it->first);
if (use != possibleUsage.end())
strusage = use->second;
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std::string status;
switch (it->second.status) {
case OWNED:
status = "owned";
break;
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case DEALLOC:
status = "dealloc";
break;
case ALLOC:
status = "alloc";
break;
case NOALLOC:
status = "noalloc";
break;
default:
status = "?";
break;
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};
std::cout << "status=" << status << " "
<< "alloctype='" << it->second.type << "' "
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<< "possibleUsage='" << strusage << "' "
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<< "conditionalAlloc=" << (conditionalAlloc.find(it->first) != conditionalAlloc.end() ? "yes" : "no") << " "
<< "referenced=" << (referenced.find(it->first) != referenced.end() ? "yes" : "no") << " "
<< std::endl;
}
}
void VarInfo::possibleUsageAll(const std::string &functionName)
{
possibleUsage.clear();
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for (std::map<unsigned int, AllocInfo>::const_iterator it = alloctype.begin(); it != alloctype.end(); ++it)
possibleUsage[it->first] = functionName;
}
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void CheckLeakAutoVar::leakError(const Token *tok, const std::string &varname, int type)
{
const CheckMemoryLeak checkmemleak(mTokenizer, mErrorLogger, mSettings);
if (mSettings->library.isresource(type))
checkmemleak.resourceLeakError(tok, varname);
else
checkmemleak.memleakError(tok, varname);
}
void CheckLeakAutoVar::mismatchError(const Token *tok, const std::string &varname)
{
const CheckMemoryLeak c(mTokenizer, mErrorLogger, mSettings);
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const std::list<const Token *> callstack(1, tok);
c.mismatchAllocDealloc(callstack, varname);
}
void CheckLeakAutoVar::deallocUseError(const Token *tok, const std::string &varname)
{
const CheckMemoryLeak c(mTokenizer, mErrorLogger, mSettings);
c.deallocuseError(tok, varname);
}
void CheckLeakAutoVar::deallocReturnError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::error, "deallocret", "$symbol:" + varname + "\nReturning/dereferencing '$symbol' after it is deallocated / released", CWE672, false);
}
void CheckLeakAutoVar::configurationInfo(const Token* tok, const std::string &functionName)
{
if (mSettings->checkLibrary && mSettings->isEnabled(Settings::INFORMATION)) {
reportError(tok,
Severity::information,
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"checkLibraryUseIgnore",
"--check-library: Function " + functionName + "() should have <use>/<leak-ignore> configuration");
}
}
void CheckLeakAutoVar::doubleFreeError(const Token *tok, const std::string &varname, int type)
{
if (mSettings->library.isresource(type))
reportError(tok, Severity::error, "doubleFree", "$symbol:" + varname + "\nResource handle '$symbol' freed twice.", CWE415, false);
else
reportError(tok, Severity::error, "doubleFree", "$symbol:" + varname + "\nMemory pointed to by '$symbol' is freed twice.", CWE415, false);
}
void CheckLeakAutoVar::check()
{
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
// Local variables that are known to be non-zero.
const std::set<unsigned int> notzero;
// Check function scopes
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for (const Scope * scope : symbolDatabase->functionScopes) {
if (scope->hasInlineOrLambdaFunction())
continue;
// Empty variable info
VarInfo varInfo;
checkScope(scope->bodyStart, &varInfo, notzero, 0);
varInfo.conditionalAlloc.clear();
// Clear reference arguments from varInfo..
std::map<unsigned int, VarInfo::AllocInfo>::iterator it = varInfo.alloctype.begin();
while (it != varInfo.alloctype.end()) {
const Variable *var = symbolDatabase->getVariableFromVarId(it->first);
if (!var ||
(var->isArgument() && var->isReference()) ||
(!var->isArgument() && !var->isLocal()))
varInfo.alloctype.erase(it++);
else
++it;
}
ret(scope->bodyEnd, varInfo);
}
}
static bool isVarUsedInTree(const Token *tok, unsigned int varid)
{
if (!tok)
return false;
if (tok->varId() == varid)
return true;
if (tok->str() == "(" && Token::simpleMatch(tok->astOperand1(), "sizeof"))
return false;
return isVarUsedInTree(tok->astOperand1(), varid) || isVarUsedInTree(tok->astOperand2(), varid);
}
static bool isPointerReleased(const Token *startToken, const Token *endToken, unsigned int varid)
{
for (const Token *tok = startToken; tok && tok != endToken; tok = tok->next()) {
if (tok->varId() != varid)
continue;
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if (Token::Match(tok, "%var% . release ( )"))
return true;
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if (Token::Match(tok, "%var% ="))
return false;
}
return false;
}
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/** checks if nameToken is a name of a function in a function call:
* func(arg)
* or
* func<temp1_arg>(arg)
* @param nameToken Function name token
* @return opening parenthesis token or NULL if not a function call
*/
static const Token * isFunctionCall(const Token * nameToken)
{
if (nameToken->isName()) {
nameToken = nameToken->next();
// check if function is a template
if (nameToken && nameToken->link() && nameToken->str() == "<") {
// skip template arguments
nameToken = nameToken->link()->next();
}
// check for '('
if (nameToken && nameToken->link() && nameToken->str() == "(") {
// returning opening parenthesis pointer
return nameToken;
}
}
return nullptr;
}
void CheckLeakAutoVar::checkScope(const Token * const startToken,
VarInfo *varInfo,
std::set<unsigned int> notzero,
unsigned int recursiveCount)
{
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if (++recursiveCount > 1000) // maximum number of "else if ()"
throw InternalError(startToken, "Internal limit: CheckLeakAutoVar::checkScope() Maximum recursive count of 1000 reached.", InternalError::LIMIT);
std::map<unsigned int, VarInfo::AllocInfo> &alloctype = varInfo->alloctype;
std::map<unsigned int, std::string> &possibleUsage = varInfo->possibleUsage;
const std::set<unsigned int> conditionalAlloc(varInfo->conditionalAlloc);
// Parse all tokens
const Token * const endToken = startToken->link();
for (const Token *tok = startToken; tok && tok != endToken; tok = tok->next()) {
if (!tok->scope()->isExecutable()) {
tok = tok->scope()->bodyEnd;
if (!tok) // Ticket #6666 (crash upon invalid code)
break;
}
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// check each token
{
const Token * nextTok = checkTokenInsideExpression(tok, varInfo);
if (nextTok) {
tok = nextTok;
continue;
}
}
// look for end of statement
if (!Token::Match(tok, "[;{}]") || Token::Match(tok->next(), "[;{}]"))
continue;
tok = tok->next();
if (!tok || tok == endToken)
break;
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// parse statement, skip to last member
const Token *varTok = tok;
while (Token::Match(varTok, "%name% ::|. %name% !!("))
varTok = varTok->tokAt(2);
const Token *ftok = tok;
if (ftok->str() == "::")
ftok = ftok->next();
while (Token::Match(ftok, "%name% :: %name%"))
ftok = ftok->tokAt(2);
// assignment..
if (Token::Match(varTok, "%var% =")) {
const Token* const tokAssignOp = varTok->next();
// taking address of another variable..
if (Token::Match(tokAssignOp, "= %var% [+;]")) {
if (varTok->tokAt(2)->varId() != varTok->varId()) {
// If variable points at allocated memory => error
leakIfAllocated(varTok, *varInfo);
// no multivariable checking currently => bail out for rhs variables
for (const Token *tok2 = varTok; tok2; tok2 = tok2->next()) {
if (tok2->str() == ";") {
break;
}
if (tok2->varId()) {
varInfo->erase(tok2->varId());
}
}
}
}
// right ast part (after `=` operator)
const Token* tokRightAstOperand = tokAssignOp->astOperand2();
while (tokRightAstOperand && tokRightAstOperand->isCast())
tokRightAstOperand = tokRightAstOperand->astOperand2() ? tokRightAstOperand->astOperand2() : tokRightAstOperand->astOperand1();
// is variable used in rhs?
if (isVarUsedInTree(tokRightAstOperand, varTok->varId()))
continue;
// Variable has already been allocated => error
if (conditionalAlloc.find(varTok->varId()) == conditionalAlloc.end())
leakIfAllocated(varTok, *varInfo);
varInfo->erase(varTok->varId());
// not a local variable nor argument?
const Variable *var = varTok->variable();
if (var && !var->isArgument() && (!var->isLocal() || var->isStatic()))
continue;
// Don't check reference variables
if (var && var->isReference())
continue;
// non-pod variable
if (mTokenizer->isCPP()) {
if (!var)
continue;
// Possibly automatically deallocated memory
if (!var->typeStartToken()->isStandardType() && Token::Match(varTok, "%var% = new"))
continue;
if (!var->isPointer() && !var->typeStartToken()->isStandardType())
continue;
}
// allocation?
const Token *const fTok = tokRightAstOperand ? tokRightAstOperand->previous() : nullptr;
if (Token::Match(fTok, "%type% (")) {
const Library::AllocFunc* f = mSettings->library.getAllocFuncInfo(fTok);
if (f && f->arg == -1) {
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VarInfo::AllocInfo& varAlloc = alloctype[varTok->varId()];
varAlloc.type = f->groupId;
varAlloc.status = VarInfo::ALLOC;
}
changeAllocStatusIfRealloc(alloctype, fTok, varTok);
} else if (mTokenizer->isCPP() && Token::Match(varTok->tokAt(2), "new !!(")) {
const Token* tok2 = varTok->tokAt(2)->astOperand1();
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const bool arrayNew = (tok2 && (tok2->str() == "[" || (tok2->str() == "(" && tok2->astOperand1() && tok2->astOperand1()->str() == "[")));
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VarInfo::AllocInfo& varAlloc = alloctype[varTok->varId()];
varAlloc.type = arrayNew ? NEW_ARRAY : NEW;
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varAlloc.status = VarInfo::ALLOC;
}
// Assigning non-zero value variable. It might be used to
// track the execution for a later if condition.
if (Token::Match(varTok->tokAt(2), "%num% ;") && MathLib::toLongNumber(varTok->strAt(2)) != 0)
notzero.insert(varTok->varId());
else if (Token::Match(varTok->tokAt(2), "- %type% ;") && varTok->tokAt(3)->isUpperCaseName())
notzero.insert(varTok->varId());
else
notzero.erase(varTok->varId());
}
// if/else
else if (Token::simpleMatch(tok, "if (")) {
// Parse function calls inside the condition
const Token * closingParenthesis = tok->linkAt(1);
for (const Token *innerTok = tok->tokAt(2); innerTok && innerTok != closingParenthesis; innerTok = innerTok->next()) {
// TODO: replace with checkTokenInsideExpression()
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if (Token::Match(innerTok, "%var% =") && innerTok->astParent() == innerTok->next()) {
// allocation?
// right ast part (after `=` operator)
const Token* tokRightAstOperand = innerTok->next()->astOperand2();
while (tokRightAstOperand && tokRightAstOperand->isCast())
tokRightAstOperand = tokRightAstOperand->astOperand2() ? tokRightAstOperand->astOperand2() : tokRightAstOperand->astOperand1();
if (tokRightAstOperand && Token::Match(tokRightAstOperand->previous(), "%type% (")) {
const Library::AllocFunc* f = mSettings->library.getAllocFuncInfo(tokRightAstOperand->previous());
if (f && f->arg == -1) {
VarInfo::AllocInfo& varAlloc = alloctype[innerTok->varId()];
varAlloc.type = f->groupId;
varAlloc.status = VarInfo::ALLOC;
} else {
// Fixme: warn about leak
alloctype.erase(innerTok->varId());
}
changeAllocStatusIfRealloc(alloctype, innerTok->tokAt(2), varTok);
} else if (mTokenizer->isCPP() && Token::Match(innerTok->tokAt(2), "new !!(")) {
const Token* tok2 = innerTok->tokAt(2)->astOperand1();
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const bool arrayNew = (tok2 && (tok2->str() == "[" || (tok2->str() == "(" && tok2->astOperand1() && tok2->astOperand1()->str() == "[")));
VarInfo::AllocInfo& varAlloc = alloctype[innerTok->varId()];
varAlloc.type = arrayNew ? NEW_ARRAY : NEW;
varAlloc.status = VarInfo::ALLOC;
}
}
// check for function call
const Token * const openingPar = isFunctionCall(innerTok);
if (openingPar) {
// innerTok is a function name
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const VarInfo::AllocInfo allocation(0, VarInfo::NOALLOC);
functionCall(innerTok, openingPar, varInfo, allocation, nullptr);
innerTok = openingPar->link();
}
}
if (Token::simpleMatch(closingParenthesis, ") {")) {
VarInfo varInfo1(*varInfo); // VarInfo for if code
VarInfo varInfo2(*varInfo); // VarInfo for else code
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// Recursively scan variable comparisons in condition
std::stack<const Token *> tokens;
tokens.push(tok->next()->astOperand2());
while (!tokens.empty()) {
const Token *tok3 = tokens.top();
tokens.pop();
if (!tok3)
continue;
if (tok3->str() == "&&" || tok3->str() == "||") {
// FIXME: handle && ! || better
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tokens.push(tok3->astOperand1());
tokens.push(tok3->astOperand2());
continue;
}
if (tok3->str() == "(" && Token::Match(tok3->astOperand1(), "UNLIKELY|LIKELY")) {
tokens.push(tok3->astOperand2());
continue;
} else if (tok3->str() == "(" && Token::Match(tok3->previous(), "%name%")) {
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const std::vector<const Token *> params = getArguments(tok3->previous());
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for (const Token *par : params) {
if (!par->isComparisonOp())
continue;
const Token *vartok = nullptr;
if (astIsVariableComparison(par, "!=", "0", &vartok) ||
astIsVariableComparison(par, "==", "0", &vartok) ||
astIsVariableComparison(par, "<", "0", &vartok) ||
astIsVariableComparison(par, ">", "0", &vartok) ||
astIsVariableComparison(par, "==", "-1", &vartok) ||
astIsVariableComparison(par, "!=", "-1", &vartok)) {
varInfo1.erase(vartok->varId());
varInfo2.erase(vartok->varId());
}
}
continue;
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}
const Token *vartok = nullptr;
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if (astIsVariableComparison(tok3, "!=", "0", &vartok)) {
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varInfo2.erase(vartok->varId());
if (notzero.find(vartok->varId()) != notzero.end())
varInfo2.clear();
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} else if (astIsVariableComparison(tok3, "==", "0", &vartok)) {
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varInfo1.erase(vartok->varId());
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} else if (astIsVariableComparison(tok3, "<", "0", &vartok)) {
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varInfo1.erase(vartok->varId());
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} else if (astIsVariableComparison(tok3, ">", "0", &vartok)) {
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varInfo2.erase(vartok->varId());
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} else if (astIsVariableComparison(tok3, "==", "-1", &vartok)) {
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varInfo1.erase(vartok->varId());
}
}
checkScope(closingParenthesis->next(), &varInfo1, notzero, recursiveCount);
closingParenthesis = closingParenthesis->linkAt(1);
if (Token::simpleMatch(closingParenthesis, "} else {")) {
checkScope(closingParenthesis->tokAt(2), &varInfo2, notzero, recursiveCount);
tok = closingParenthesis->linkAt(2)->previous();
} else {
tok = closingParenthesis->previous();
}
VarInfo old;
old.swap(*varInfo);
std::map<unsigned int, VarInfo::AllocInfo>::const_iterator it;
for (it = old.alloctype.begin(); it != old.alloctype.end(); ++it) {
const unsigned int varId = it->first;
if (old.conditionalAlloc.find(varId) == old.conditionalAlloc.end())
continue;
if (varInfo1.alloctype.find(varId) == varInfo1.alloctype.end() ||
varInfo2.alloctype.find(varId) == varInfo2.alloctype.end()) {
varInfo1.erase(varId);
varInfo2.erase(varId);
}
}
// Conditional allocation in varInfo1
for (it = varInfo1.alloctype.begin(); it != varInfo1.alloctype.end(); ++it) {
if (varInfo2.alloctype.find(it->first) == varInfo2.alloctype.end() &&
old.alloctype.find(it->first) == old.alloctype.end()) {
varInfo->conditionalAlloc.insert(it->first);
}
}
// Conditional allocation in varInfo2
for (it = varInfo2.alloctype.begin(); it != varInfo2.alloctype.end(); ++it) {
if (varInfo1.alloctype.find(it->first) == varInfo1.alloctype.end() &&
old.alloctype.find(it->first) == old.alloctype.end()) {
varInfo->conditionalAlloc.insert(it->first);
}
}
// Conditional allocation/deallocation
for (it = varInfo1.alloctype.begin(); it != varInfo1.alloctype.end(); ++it) {
if (it->second.managed() && conditionalAlloc.find(it->first) != conditionalAlloc.end()) {
varInfo->conditionalAlloc.erase(it->first);
varInfo2.erase(it->first);
}
}
for (it = varInfo2.alloctype.begin(); it != varInfo2.alloctype.end(); ++it) {
if (it->second.managed() && conditionalAlloc.find(it->first) != conditionalAlloc.end()) {
varInfo->conditionalAlloc.erase(it->first);
varInfo1.erase(it->first);
}
}
alloctype.insert(varInfo1.alloctype.begin(), varInfo1.alloctype.end());
alloctype.insert(varInfo2.alloctype.begin(), varInfo2.alloctype.end());
possibleUsage.insert(varInfo1.possibleUsage.begin(), varInfo1.possibleUsage.end());
possibleUsage.insert(varInfo2.possibleUsage.begin(), varInfo2.possibleUsage.end());
}
}
// unknown control.. (TODO: handle loops)
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else if ((Token::Match(tok, "%type% (") && Token::simpleMatch(tok->linkAt(1), ") {")) || Token::simpleMatch(tok, "do {")) {
varInfo->clear();
break;
}
// return
else if (tok->str() == "return") {
ret(tok, *varInfo);
varInfo->clear();
}
// throw
else if (mTokenizer->isCPP() && tok->str() == "throw") {
bool tryFound = false;
const Scope* scope = tok->scope();
while (scope && scope->isExecutable()) {
if (scope->type == Scope::eTry)
tryFound = true;
scope = scope->nestedIn;
}
// If the execution leaves the function then treat it as return
if (!tryFound)
ret(tok, *varInfo);
varInfo->clear();
}
// delete
else if (mTokenizer->isCPP() && tok->str() == "delete") {
const bool arrayDelete = Token::simpleMatch(tok->next(), "[ ]");
if (arrayDelete)
tok = tok->tokAt(3);
else
tok = tok->next();
if (tok->str() == "(")
tok = tok->next();
while (Token::Match(tok, "%name% ::|."))
tok = tok->tokAt(2);
const bool isnull = tok->hasKnownIntValue() && tok->values().front().intvalue == 0;
if (!isnull && tok->varId() && tok->strAt(1) != "[") {
const VarInfo::AllocInfo allocation(arrayDelete ? NEW_ARRAY : NEW, VarInfo::DEALLOC);
changeAllocStatus(varInfo, allocation, tok, tok);
}
}
// Function call..
else if (isFunctionCall(ftok)) {
const Token * openingPar = isFunctionCall(ftok);
const Library::AllocFunc* af = mSettings->library.getDeallocFuncInfo(ftok);
VarInfo::AllocInfo allocation(af ? af->groupId : 0, VarInfo::DEALLOC);
if (allocation.type == 0)
allocation.status = VarInfo::NOALLOC;
functionCall(ftok, openingPar, varInfo, allocation, af);
tok = ftok->next()->link();
// Handle scopes that might be noreturn
if (allocation.status == VarInfo::NOALLOC && Token::simpleMatch(tok, ") ; }")) {
const std::string &functionName(tok->link()->previous()->str());
bool unknown = false;
if (mTokenizer->IsScopeNoReturn(tok->tokAt(2), &unknown)) {
if (!unknown)
varInfo->clear();
else if (!mSettings->library.isLeakIgnore(functionName) && !mSettings->library.isUse(functionName))
varInfo->possibleUsageAll(functionName);
}
}
continue;
}
// goto => weird execution path
else if (tok->str() == "goto") {
varInfo->clear();
}
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// continue/break
else if (Token::Match(tok, "continue|break ;")) {
varInfo->clear();
}
// Check smart pointer
else if (Token::Match(ftok, "%name% <") && mSettings->library.isSmartPointer(tok)) {
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const Token * typeEndTok = ftok->linkAt(1);
if (!Token::Match(typeEndTok, "> %var% {|( %var% ,|)|}"))
continue;
tok = typeEndTok->linkAt(2);
const unsigned varid = typeEndTok->next()->varId();
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if (isPointerReleased(typeEndTok->tokAt(2), endToken, varid))
continue;
bool arrayDelete = false;
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if (Token::findsimplematch(ftok->next(), "[ ]", typeEndTok))
arrayDelete = true;
// Check deleter
const Token * deleterToken = nullptr;
const Token * endDeleterToken = nullptr;
const Library::AllocFunc* af = nullptr;
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if (Token::Match(ftok, "unique_ptr < %type% ,")) {
deleterToken = ftok->tokAt(4);
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endDeleterToken = typeEndTok;
} else if (Token::Match(typeEndTok, "> %var% {|( %var% ,")) {
deleterToken = typeEndTok->tokAt(5);
endDeleterToken = typeEndTok->linkAt(2);
}
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if (deleterToken) {
// Skip the decaying plus in expressions like +[](T*){}
if (deleterToken->str() == "+") {
deleterToken = deleterToken->next();
}
// Check if its a pointer to a function
const Token * dtok = Token::findmatch(deleterToken, "& %name%", endDeleterToken);
if (dtok) {
af = mSettings->library.getDeallocFuncInfo(dtok->tokAt(1));
} else {
const Token * tscopeStart = nullptr;
const Token * tscopeEnd = nullptr;
// If the deleter is a lambda, check if it calls the dealloc function
if (deleterToken->str() == "[" &&
Token::simpleMatch(deleterToken->link(), "] (") &&
// TODO: Check for mutable keyword
Token::simpleMatch(deleterToken->link()->linkAt(1), ") {")) {
tscopeStart = deleterToken->link()->linkAt(1)->tokAt(1);
tscopeEnd = tscopeStart->link();
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// If the deleter is a class, check if class calls the dealloc function
} else if ((dtok = Token::findmatch(deleterToken, "%type%", endDeleterToken)) && dtok->type()) {
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const Scope * tscope = dtok->type()->classScope;
if (tscope) {
tscopeStart = tscope->bodyStart;
tscopeEnd = tscope->bodyEnd;
}
}
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if (tscopeStart && tscopeEnd) {
for (const Token *tok2 = tscopeStart; tok2 != tscopeEnd; tok2 = tok2->next()) {
af = mSettings->library.getDeallocFuncInfo(tok2);
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if (af)
break;
}
}
}
}
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const Token * vtok = typeEndTok->tokAt(3);
const VarInfo::AllocInfo allocation(af ? af->groupId : (arrayDelete ? NEW_ARRAY : NEW), VarInfo::OWNED);
changeAllocStatus(varInfo, allocation, vtok, vtok);
}
}
}
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const Token * CheckLeakAutoVar::checkTokenInsideExpression(const Token * const tok, VarInfo *varInfo)
{
// Deallocation and then dereferencing pointer..
if (tok->varId() > 0) {
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// TODO : Write a separate checker for this that uses valueFlowForward.
const std::map<unsigned int, VarInfo::AllocInfo>::const_iterator var = varInfo->alloctype.find(tok->varId());
if (var != varInfo->alloctype.end()) {
bool unknown = false;
if (var->second.status == VarInfo::DEALLOC && CheckNullPointer::isPointerDeRef(tok, unknown, mSettings) && !unknown) {
deallocUseError(tok, tok->str());
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} else if (Token::simpleMatch(tok->tokAt(-2), "= &")) {
varInfo->erase(tok->varId());
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} else if (tok->strAt(-1) == "=") {
varInfo->erase(tok->varId());
}
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} else if (Token::Match(tok->previous(), "& %name% = %var% ;")) {
varInfo->referenced.insert(tok->tokAt(2)->varId());
}
}
// check for function call
const Token * const openingPar = isFunctionCall(tok);
if (openingPar) {
const Library::AllocFunc* allocFunc = mSettings->library.getDeallocFuncInfo(tok);
VarInfo::AllocInfo alloc(allocFunc ? allocFunc->groupId : 0, VarInfo::DEALLOC);
if (alloc.type == 0)
alloc.status = VarInfo::NOALLOC;
functionCall(tok, openingPar, varInfo, alloc, nullptr);
return openingPar->link();
}
return nullptr;
}
void CheckLeakAutoVar::changeAllocStatusIfRealloc(std::map<unsigned int, VarInfo::AllocInfo> &alloctype, const Token *fTok, const Token *retTok)
{
const Library::AllocFunc* f = mSettings->library.getReallocFuncInfo(fTok);
if (f && f->arg == -1 && f->reallocArg > 0 && f->reallocArg <= numberOfArguments(fTok)) {
const Token* argTok = getArguments(fTok).at(f->reallocArg - 1);
VarInfo::AllocInfo& argAlloc = alloctype[argTok->varId()];
VarInfo::AllocInfo& retAlloc = alloctype[retTok->varId()];
if (argAlloc.type != 0 && argAlloc.type != f->groupId)
mismatchError(fTok, argTok->str());
argAlloc.status = VarInfo::DEALLOC;
retAlloc.type = f->groupId;
retAlloc.status = VarInfo::ALLOC;
}
}
void CheckLeakAutoVar::changeAllocStatus(VarInfo *varInfo, const VarInfo::AllocInfo& allocation, const Token* tok, const Token* arg)
{
std::map<unsigned int, VarInfo::AllocInfo> &alloctype = varInfo->alloctype;
const std::map<unsigned int, VarInfo::AllocInfo>::iterator var = alloctype.find(arg->varId());
if (var != alloctype.end()) {
if (allocation.status == VarInfo::NOALLOC) {
// possible usage
varInfo->possibleUsage[arg->varId()] = tok->str();
if (var->second.status == VarInfo::DEALLOC && arg->previous()->str() == "&")
varInfo->erase(arg->varId());
} else if (var->second.managed()) {
doubleFreeError(tok, arg->str(), allocation.type);
} else if (var->second.type != allocation.type) {
// mismatching allocation and deallocation
mismatchError(tok, arg->str());
varInfo->erase(arg->varId());
} else {
// deallocation
var->second.status = allocation.status;
var->second.type = allocation.type;
}
} else if (allocation.status != VarInfo::NOALLOC) {
alloctype[arg->varId()].status = VarInfo::DEALLOC;
}
}
void CheckLeakAutoVar::functionCall(const Token *tokName, const Token *tokOpeningPar, VarInfo *varInfo, const VarInfo::AllocInfo& allocation, const Library::AllocFunc* af)
{
// Ignore function call?
if (mSettings->library.isLeakIgnore(tokName->str()))
return;
if (mSettings->library.getReallocFuncInfo(tokName))
return;
const Token * const tokFirstArg = tokOpeningPar->next();
if (!tokFirstArg || tokFirstArg->str() == ")") {
// no arguments
return;
}
int argNr = 1;
for (const Token *arg = tokFirstArg; arg; arg = arg->nextArgument()) {
if (mTokenizer->isCPP() && arg->str() == "new") {
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arg = arg->next();
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if (Token::simpleMatch(arg, "( std :: nothrow )"))
arg = arg->tokAt(5);
}
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// Skip casts
while (arg && arg->isCast())
arg = arg->astOperand2() ? arg->astOperand2() : arg->astOperand1();
const Token * const argTypeStartTok = arg;
while (Token::Match(arg, "%name% .|:: %name%"))
arg = arg->tokAt(2);
if (Token::Match(arg, "%var% [-,)] !!.") || Token::Match(arg, "& %var%")) {
// goto variable
if (arg->str() == "&")
arg = arg->next();
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const bool isnull = arg->hasKnownIntValue() && arg->values().front().intvalue == 0;
// Is variable allocated?
if (!isnull && (!af || af->arg == argNr))
changeAllocStatus(varInfo, allocation, tokName, arg);
}
// Check smart pointer
else if (Token::Match(arg, "%name% < %type%") && mSettings->library.isSmartPointer(argTypeStartTok)) {
const Token * typeEndTok = arg->linkAt(1);
if (!Token::Match(typeEndTok, "> {|( %var% ,|)|}"))
continue;
bool arrayDelete = false;
if (Token::findsimplematch(arg->next(), "[ ]", typeEndTok))
arrayDelete = true;
// Check deleter
const Token * deleterToken = nullptr;
const Token * endDeleterToken = nullptr;
const Library::AllocFunc* sp_af = nullptr;
if (Token::Match(arg, "unique_ptr < %type% ,")) {
deleterToken = arg->tokAt(4);
endDeleterToken = typeEndTok;
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} else if (Token::Match(typeEndTok, "> {|( %var% ,")) {
deleterToken = typeEndTok->tokAt(4);
endDeleterToken = typeEndTok->linkAt(1);
}
if (deleterToken) {
// Check if its a pointer to a function
const Token * dtok = Token::findmatch(deleterToken, "& %name%", endDeleterToken);
if (dtok) {
sp_af = mSettings->library.getDeallocFuncInfo(dtok->tokAt(1));
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} else {
// If the deleter is a class, check if class calls the dealloc function
dtok = Token::findmatch(deleterToken, "%type%", endDeleterToken);
if (dtok && dtok->type()) {
const Scope * tscope = dtok->type()->classScope;
for (const Token *tok2 = tscope->bodyStart; tok2 != tscope->bodyEnd; tok2 = tok2->next()) {
sp_af = mSettings->library.getDeallocFuncInfo(tok2);
if (sp_af)
break;
}
}
}
}
const Token * vtok = typeEndTok->tokAt(2);
const VarInfo::AllocInfo sp_allocation(sp_af ? sp_af->groupId : (arrayDelete ? NEW_ARRAY : NEW), VarInfo::OWNED);
changeAllocStatus(varInfo, sp_allocation, vtok, vtok);
} else {
checkTokenInsideExpression(arg, varInfo);
}
// TODO: check each token in argument expression (could contain multiple variables)
argNr++;
}
}
void CheckLeakAutoVar::leakIfAllocated(const Token *vartok,
const VarInfo &varInfo)
{
const std::map<unsigned int, VarInfo::AllocInfo> &alloctype = varInfo.alloctype;
const std::map<unsigned int, std::string> &possibleUsage = varInfo.possibleUsage;
const std::map<unsigned int, VarInfo::AllocInfo>::const_iterator var = alloctype.find(vartok->varId());
if (var != alloctype.end() && var->second.status == VarInfo::ALLOC) {
const std::map<unsigned int, std::string>::const_iterator use = possibleUsage.find(vartok->varId());
if (use == possibleUsage.end()) {
leakError(vartok, vartok->str(), var->second.type);
} else {
configurationInfo(vartok, use->second);
}
}
}
void CheckLeakAutoVar::ret(const Token *tok, const VarInfo &varInfo)
{
const std::map<unsigned int, VarInfo::AllocInfo> &alloctype = varInfo.alloctype;
const std::map<unsigned int, std::string> &possibleUsage = varInfo.possibleUsage;
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
for (std::map<unsigned int, VarInfo::AllocInfo>::const_iterator it = alloctype.begin(); it != alloctype.end(); ++it) {
// don't warn if variable is conditionally allocated
if (!it->second.managed() && varInfo.conditionalAlloc.find(it->first) != varInfo.conditionalAlloc.end())
continue;
// don't warn if there is a reference of the variable
if (varInfo.referenced.find(it->first) != varInfo.referenced.end())
continue;
const unsigned int varid = it->first;
const Variable *var = symbolDatabase->getVariableFromVarId(varid);
if (var) {
bool used = false;
for (const Token *tok2 = tok; tok2; tok2 = tok2->next()) {
if (tok2->str() == ";")
break;
if (Token::Match(tok2, "return|(|, %varid% [);,]", varid)) {
used = true;
break;
}
if (Token::Match(tok2, "return|(|, & %varid% . %name% [);,]", varid)) {
used = true;
break;
}
}
// return deallocated pointer
if (used && it->second.status == VarInfo::DEALLOC)
deallocReturnError(tok, var->name());
else if (!used && !it->second.managed()) {
const std::map<unsigned int, std::string>::const_iterator use = possibleUsage.find(varid);
if (use == possibleUsage.end()) {
leakError(tok, var->name(), it->second.type);
} else {
configurationInfo(tok, use->second);
}
}
}
}
}