495 lines
19 KiB
C++
495 lines
19 KiB
C++
/*
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* Cppcheck - A tool for static C/C++ code analysis
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* Copyright (C) 2007-2013 Daniel Marjamäki and Cppcheck team.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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//---------------------------------------------------------------------------
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// Leaks when using auto variables
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//---------------------------------------------------------------------------
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#include "checkleakautovar.h"
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#include "checkmemoryleak.h" // <- CheckMemoryLeak::memoryLeak
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#include "checkother.h" // <- doubleFreeError
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#include "tokenize.h"
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#include "errorlogger.h"
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#include "symboldatabase.h"
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#include <fstream>
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//---------------------------------------------------------------------------
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const int DEALLOC = -1;
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const int NOALLOC = 0;
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// Register this check class (by creating a static instance of it)
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namespace {
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CheckLeakAutoVar instance;
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}
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//---------------------------------------------------------------------------
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void VarInfo::print()
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{
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std::cout << "size=" << alloctype.size() << std::endl;
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std::map<unsigned int, int>::const_iterator it;
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for (it = alloctype.begin(); it != alloctype.end(); ++it) {
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std::string strusage;
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std::map<unsigned int, std::string>::const_iterator use = possibleUsage.find(it->first);
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if (use != possibleUsage.end())
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strusage = use->second;
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std::cout << "alloctype='" << it->second << "' "
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<< "possibleUsage='" << strusage << "'" << std::endl;
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}
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}
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void VarInfo::possibleUsageAll(const std::string &functionName)
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{
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possibleUsage.clear();
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std::map<unsigned int, int>::const_iterator it;
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for (it = alloctype.begin(); it != alloctype.end(); ++it)
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possibleUsage[it->first] = functionName;
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}
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void CheckLeakAutoVar::leakError(const Token *tok, const std::string &varname, int type)
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{
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const CheckMemoryLeak checkmemleak(_tokenizer, _errorLogger, _settings);
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if (_settings->library.isresource(type))
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checkmemleak.resourceLeakError(tok, varname);
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else
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checkmemleak.memleakError(tok, varname);
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}
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void CheckLeakAutoVar::mismatchError(const Token *tok, const std::string &varname)
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{
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const CheckMemoryLeak c(_tokenizer, _errorLogger, _settings);
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std::list<const Token *> callstack(1, tok);
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c.mismatchAllocDealloc(callstack, varname);
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}
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void CheckLeakAutoVar::deallocUseError(const Token *tok, const std::string &varname)
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{
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const CheckMemoryLeak c(_tokenizer, _errorLogger, _settings);
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c.deallocuseError(tok, varname);
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}
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void CheckLeakAutoVar::deallocReturnError(const Token *tok, const std::string &varname)
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{
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reportError(tok, Severity::error, "deallocret", "Returning/dereferencing '" + varname + "' after it is deallocated / released");
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}
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void CheckLeakAutoVar::configurationInfo(const Token* tok, const std::string &functionName)
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{
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if (_settings->checkLibrary && _settings->isEnabled("information")) {
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reportError(tok,
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Severity::information,
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"checkLibraryUseIgnore",
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"--check-library: Function " + functionName + "() should have <use>/<ignore> configuration");
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}
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}
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void CheckLeakAutoVar::check()
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{
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const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
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// Check function scopes
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const std::size_t functions = symbolDatabase->functionScopes.size();
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for (std::size_t i = 0; i < functions; ++i) {
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const Scope * scope = symbolDatabase->functionScopes[i];
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// Empty variable info
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VarInfo varInfo;
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// Local variables that are known to be non-zero.
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static const std::set<unsigned int> notzero;
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checkScope(scope->classStart, &varInfo, notzero);
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varInfo.conditionalAlloc.clear();
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// Clear reference arguments from varInfo..
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std::map<unsigned int, int>::iterator it = varInfo.alloctype.begin();
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while (it != varInfo.alloctype.end()) {
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const Variable *var = symbolDatabase->getVariableFromVarId(it->first);
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if (!var ||
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(var->isArgument() && var->isReference()) ||
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(!var->isArgument() && !var->isLocal()))
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varInfo.alloctype.erase(it++);
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else
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++it;
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}
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ret(scope->classEnd, varInfo);
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}
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}
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void CheckLeakAutoVar::checkScope(const Token * const startToken,
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VarInfo *varInfo,
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std::set<unsigned int> notzero)
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{
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std::map<unsigned int, int> &alloctype = varInfo->alloctype;
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std::map<unsigned int, std::string> &possibleUsage = varInfo->possibleUsage;
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const std::set<unsigned int> conditionalAlloc(varInfo->conditionalAlloc);
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// Parse all tokens
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const Token * const endToken = startToken->link();
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for (const Token *tok = startToken; tok && tok != endToken; tok = tok->next()) {
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// Deallocation and then dereferencing pointer..
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if (tok->varId() > 0) {
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const std::map<unsigned int, int>::iterator var = alloctype.find(tok->varId());
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if (var != alloctype.end()) {
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if (var->second == DEALLOC && !Token::Match(tok->previous(), "[;{},=] %var% =")) {
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deallocUseError(tok, tok->str());
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} else if (Token::simpleMatch(tok->tokAt(-2), "= &")) {
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varInfo->erase(tok->varId());
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} else if (tok->strAt(-1) == "=") {
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varInfo->erase(tok->varId());
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}
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} else if (Token::Match(tok->previous(), "& %var% = %var% ;")) {
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varInfo->referenced.insert(tok->tokAt(2)->varId());
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}
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}
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if (tok->str() == "(" && tok->previous()->isName()) {
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functionCall(tok->previous(), varInfo, NOALLOC);
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tok = tok->link();
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continue;
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}
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// look for end of statement
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if (!Token::Match(tok, "[;{}]") || Token::Match(tok->next(), "[;{}]"))
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continue;
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tok = tok->next();
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if (!tok || tok == endToken)
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break;
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// parse statement
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// assignment..
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if (tok->varId() && Token::Match(tok, "%var% =")) {
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// taking address of another variable..
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if (Token::Match(tok->next(), "= %var% [+;]")) {
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if (tok->tokAt(2)->varId() != tok->varId()) {
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// If variable points at allocated memory => error
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leakIfAllocated(tok, *varInfo);
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// no multivariable checking currently => bail out for rhs variables
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for (const Token *tok2 = tok; tok2; tok2 = tok2->next()) {
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if (tok2->str() == ";") {
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break;
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}
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if (tok2->varId()) {
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varInfo->erase(tok2->varId());
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}
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}
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}
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}
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// is variable used in rhs?
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bool used_in_rhs = false;
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for (const Token *tok2 = tok->tokAt(2); tok2; tok2 = tok2->next()) {
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if (tok2->str() == ";") {
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break;
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}
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if (tok->varId() == tok2->varId()) {
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used_in_rhs = true;
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break;
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}
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}
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// TODO: Better checking how the pointer is used in rhs?
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if (used_in_rhs)
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continue;
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// Variable has already been allocated => error
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if (conditionalAlloc.find(tok->varId()) == conditionalAlloc.end())
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leakIfAllocated(tok, *varInfo);
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varInfo->erase(tok->varId());
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// not a local variable nor argument?
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const Variable *var = tok->variable();
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if (var && !var->isArgument() && !var->isLocal()) {
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continue;
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}
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// Don't check reference variables
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if (var && var->isReference())
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continue;
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// allocation?
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if (Token::Match(tok->tokAt(2), "%type% (")) {
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int i = _settings->library.alloc(tok->strAt(2));
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if (i > 0) {
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alloctype[tok->varId()] = i;
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}
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}
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// Assigning non-zero value variable. It might be used to
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// track the execution for a later if condition.
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if (Token::Match(tok->tokAt(2), "%num% ;") && MathLib::toLongNumber(tok->strAt(2)) != 0)
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notzero.insert(tok->varId());
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else if (Token::Match(tok->tokAt(2), "- %type% ;") && tok->tokAt(3)->isUpperCaseName())
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notzero.insert(tok->varId());
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else
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notzero.erase(tok->varId());
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}
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// if/else
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else if (Token::simpleMatch(tok, "if (")) {
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// Parse function calls inside the condition
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for (const Token *innerTok = tok->tokAt(2); innerTok; innerTok = innerTok->next()) {
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if (innerTok->str() == ")")
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break;
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if (innerTok->str() == "(" && innerTok->previous()->isName()) {
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const int deallocId = _settings->library.dealloc(tok->str());
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functionCall(innerTok->previous(), varInfo, deallocId);
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innerTok = innerTok->link();
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}
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}
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const Token *tok2 = tok->linkAt(1);
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if (Token::simpleMatch(tok2, ") {")) {
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VarInfo varInfo1(*varInfo);
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VarInfo varInfo2(*varInfo);
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if (Token::Match(tok->next(), "( %var% )")) {
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varInfo2.erase(tok->tokAt(2)->varId());
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if (notzero.find(tok->tokAt(2)->varId()) != notzero.end())
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varInfo2.clear();
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} else if (Token::Match(tok->next(), "( ! %var% )|&&")) {
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varInfo1.erase(tok->tokAt(3)->varId());
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} else if (Token::Match(tok->next(), "( %var% ( ! %var% ) )|&&")) {
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varInfo1.erase(tok->tokAt(5)->varId());
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}
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checkScope(tok2->next(), &varInfo1, notzero);
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tok2 = tok2->linkAt(1);
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if (Token::simpleMatch(tok2, "} else {")) {
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checkScope(tok2->tokAt(2), &varInfo2, notzero);
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tok = tok2->linkAt(2)->previous();
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} else {
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tok = tok2->previous();
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}
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VarInfo old;
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old.swap(*varInfo);
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// Conditional allocation in varInfo1
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std::map<unsigned int, int>::const_iterator it;
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for (it = varInfo1.alloctype.begin(); it != varInfo1.alloctype.end(); ++it) {
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if (varInfo2.alloctype.find(it->first) == varInfo2.alloctype.end() &&
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old.alloctype.find(it->first) == old.alloctype.end()) {
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varInfo->conditionalAlloc.insert(it->first);
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}
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}
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// Conditional allocation in varInfo2
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for (it = varInfo2.alloctype.begin(); it != varInfo2.alloctype.end(); ++it) {
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if (varInfo1.alloctype.find(it->first) == varInfo1.alloctype.end() &&
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old.alloctype.find(it->first) == old.alloctype.end()) {
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varInfo->conditionalAlloc.insert(it->first);
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}
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}
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// Conditional allocation/deallocation
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for (it = varInfo1.alloctype.begin(); it != varInfo1.alloctype.end(); ++it) {
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if (it->second == DEALLOC && conditionalAlloc.find(it->first) != conditionalAlloc.end()) {
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varInfo->conditionalAlloc.erase(it->first);
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varInfo2.erase(it->first);
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}
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}
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for (it = varInfo2.alloctype.begin(); it != varInfo2.alloctype.end(); ++it) {
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if (it->second == DEALLOC && conditionalAlloc.find(it->first) != conditionalAlloc.end()) {
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varInfo->conditionalAlloc.erase(it->first);
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varInfo1.erase(it->first);
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}
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}
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alloctype.insert(varInfo1.alloctype.begin(), varInfo1.alloctype.end());
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alloctype.insert(varInfo2.alloctype.begin(), varInfo2.alloctype.end());
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possibleUsage.insert(varInfo1.possibleUsage.begin(), varInfo1.possibleUsage.end());
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possibleUsage.insert(varInfo2.possibleUsage.begin(), varInfo2.possibleUsage.end());
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}
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}
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// unknown control..
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else if (Token::Match(tok, "%type% (") && Token::simpleMatch(tok->linkAt(1), ") {")) {
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varInfo->clear();
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break;
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}
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// Function call..
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else if (Token::Match(tok, "%type% (") && tok->str() != "return") {
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const int dealloc = _settings->library.dealloc(tok->str());
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functionCall(tok, varInfo, dealloc);
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tok = tok->next()->link();
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// Handle scopes that might be noreturn
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if (dealloc == NOALLOC && Token::simpleMatch(tok, ") ; }")) {
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const std::string &functionName(tok->link()->previous()->str());
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bool unknown = false;
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if (_settings->library.leakignore.find(functionName) == _settings->library.leakignore.end() &&
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_settings->library.use.find(functionName) == _settings->library.use.end() &&
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_tokenizer->IsScopeNoReturn(tok->tokAt(2), &unknown)) {
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if (unknown) {
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//const std::string &functionName(tok->link()->previous()->str());
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varInfo->possibleUsageAll(functionName);
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} else {
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varInfo->clear();
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}
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}
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}
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continue;
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}
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// return
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else if (tok->str() == "return") {
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ret(tok, *varInfo);
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varInfo->clear();
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}
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// goto => weird execution path
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else if (tok->str() == "goto") {
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varInfo->clear();
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}
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// throw
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// TODO: if the execution leave the function then treat it as return
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else if (tok->str() == "throw") {
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varInfo->clear();
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}
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}
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}
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void CheckLeakAutoVar::functionCall(const Token *tok, VarInfo *varInfo, const int dealloc)
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{
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std::map<unsigned int, int> &alloctype = varInfo->alloctype;
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std::map<unsigned int, std::string> &possibleUsage = varInfo->possibleUsage;
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// Ignore function call?
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const bool ignore = bool(_settings->library.leakignore.find(tok->str()) != _settings->library.leakignore.end());
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if (ignore)
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return;
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for (const Token *arg = tok->tokAt(2); arg; arg = arg->nextArgument()) {
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if ((Token::Match(arg, "%var% [-,)]") && arg->varId() > 0) ||
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(Token::Match(arg, "& %var%") && arg->next()->varId() > 0)) {
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// goto variable
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if (arg->str() == "&")
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arg = arg->next();
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// Is variable allocated?
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const std::map<unsigned int,int>::iterator var = alloctype.find(arg->varId());
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if (var != alloctype.end()) {
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if (dealloc == NOALLOC) {
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// possible usage
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possibleUsage[arg->varId()] = tok->str();
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if (var->second == DEALLOC && arg->previous()->str() == "&")
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varInfo->erase(arg->varId());
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} else if (var->second == DEALLOC) {
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CheckOther checkOther(_tokenizer, _settings, _errorLogger);
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checkOther.doubleFreeError(tok, arg->str());
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} else if (var->second != dealloc) {
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// mismatching allocation and deallocation
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mismatchError(tok, arg->str());
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varInfo->erase(arg->varId());
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} else {
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// deallocation
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var->second = DEALLOC;
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}
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} else if (dealloc != NOALLOC) {
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alloctype[arg->varId()] = DEALLOC;
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}
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} else if (Token::Match(arg, "%var% (")) {
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functionCall(arg, varInfo, dealloc);
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}
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}
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}
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void CheckLeakAutoVar::leakIfAllocated(const Token *vartok,
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const VarInfo &varInfo)
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{
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const std::map<unsigned int, int> &alloctype = varInfo.alloctype;
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const std::map<unsigned int, std::string> &possibleUsage = varInfo.possibleUsage;
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const std::map<unsigned int,int>::const_iterator var = alloctype.find(vartok->varId());
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if (var != alloctype.end() && var->second != DEALLOC) {
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const std::map<unsigned int, std::string>::const_iterator use = possibleUsage.find(vartok->varId());
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if (use == possibleUsage.end()) {
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leakError(vartok, vartok->str(), var->second);
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} else {
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configurationInfo(vartok, use->second);
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}
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}
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}
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void CheckLeakAutoVar::ret(const Token *tok, const VarInfo &varInfo)
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{
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const std::map<unsigned int, int> &alloctype = varInfo.alloctype;
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const std::map<unsigned int, std::string> &possibleUsage = varInfo.possibleUsage;
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const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
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for (std::map<unsigned int, int>::const_iterator it = alloctype.begin(); it != alloctype.end(); ++it) {
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// don't warn if variable is conditionally allocated
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if (it->second != DEALLOC && varInfo.conditionalAlloc.find(it->first) != varInfo.conditionalAlloc.end())
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continue;
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// don't warn if there is a reference of the variable
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if (varInfo.referenced.find(it->first) != varInfo.referenced.end())
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continue;
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const unsigned int varid = it->first;
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const Variable *var = symbolDatabase->getVariableFromVarId(varid);
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if (var) {
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bool used = false;
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for (const Token *tok2 = tok; tok2; tok2 = tok2->next()) {
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if (tok2->str() == ";")
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break;
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if (Token::Match(tok2, "return|(|, %varid% [);,]", varid)) {
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used = true;
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break;
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}
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if (Token::Match(tok2, "return|(|, & %varid% . %var% [);,]", varid)) {
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used = true;
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break;
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}
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}
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// return deallocated pointer
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if (used && it->second == DEALLOC)
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deallocReturnError(tok, var->name());
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else if (!used && it->second != DEALLOC) {
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const std::map<unsigned int, std::string>::const_iterator use = possibleUsage.find(varid);
|
|
if (use == possibleUsage.end()) {
|
|
leakError(tok, var->name(), it->second);
|
|
} else {
|
|
configurationInfo(tok, use->second);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|