1085 lines
44 KiB
C++
1085 lines
44 KiB
C++
/*
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* Cppcheck - A tool for static C/C++ code analysis
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* Copyright (C) 2007-2015 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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#include "checkuninitvar.h"
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#include "astutils.h"
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#include "mathlib.h"
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#include "checknullpointer.h" // CheckNullPointer::parseFunctionCall
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#include "symboldatabase.h"
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#include <algorithm>
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#include <map>
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#include <cassert>
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#include <stack>
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//---------------------------------------------------------------------------
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// Register this check class (by creating a static instance of it)
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namespace {
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CheckUninitVar instance;
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}
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//---------------------------------------------------------------------------
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void CheckUninitVar::check()
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{
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const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
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std::list<Scope>::const_iterator scope;
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// check every executable scope
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for (scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {
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if (scope->isExecutable()) {
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checkScope(&*scope);
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}
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}
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}
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void CheckUninitVar::checkScope(const Scope* scope)
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{
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for (std::list<Variable>::const_iterator i = scope->varlist.begin(); i != scope->varlist.end(); ++i) {
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if ((_tokenizer->isCPP() && i->type() && !i->isPointer() && i->type()->needInitialization != Type::True) ||
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i->isStatic() || i->isExtern() || i->isReference())
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continue;
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// don't warn for try/catch exception variable
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if (i->isThrow())
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continue;
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if (i->nameToken()->strAt(1) == "(" || i->nameToken()->strAt(1) == "{")
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continue;
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if (Token::Match(i->nameToken(), "%name% =")) { // Variable is initialized, but Rhs might be not
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checkRhs(i->nameToken(), *i, NO_ALLOC, 0U, "");
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continue;
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}
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if (Token::Match(i->nameToken(), "%name% ) (") && Token::simpleMatch(i->nameToken()->linkAt(2), ") =")) { // Function pointer is initialized, but Rhs might be not
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checkRhs(i->nameToken()->linkAt(2)->next(), *i, NO_ALLOC, 0U, "");
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continue;
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}
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if (i->isArray()) {
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const Token *tok = i->nameToken()->next();
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while (Token::simpleMatch(tok->link(), "] ["))
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tok = tok->link()->next();
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if (Token::simpleMatch(tok->link(), "] ="))
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continue;
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}
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bool stdtype = _tokenizer->isC();
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const Token* tok = i->typeStartToken();
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for (; tok && tok->str() != ";" && tok->str() != "<"; tok = tok->next()) {
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if (tok->isStandardType())
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stdtype = true;
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}
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if (i->isArray() && !stdtype)
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continue;
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while (tok && tok->str() != ";")
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tok = tok->next();
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if (!tok)
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continue;
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if (i->isArray()) {
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Alloc alloc = ARRAY;
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checkScopeForVariable(tok, *i, nullptr, nullptr, &alloc, "");
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continue;
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}
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if (stdtype || i->isPointer()) {
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Alloc alloc = NO_ALLOC;
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checkScopeForVariable(tok, *i, nullptr, nullptr, &alloc, "");
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}
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if (i->type())
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checkStruct(tok, *i);
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}
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if (scope->function) {
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for (unsigned int i = 0; i < scope->function->argCount(); i++) {
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const Variable *arg = scope->function->getArgumentVar(i);
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if (arg && arg->declarationId() && Token::Match(arg->typeStartToken(), "struct| %type% * %name% [,)]")) {
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// Treat the pointer as initialized until it is assigned by malloc
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for (const Token *tok = scope->classStart; tok != scope->classEnd; tok = tok->next()) {
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if (Token::Match(tok, "[;{}] %varid% = %name% (", arg->declarationId()) &&
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_settings->library.returnuninitdata.count(tok->strAt(3)) == 1U) {
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if (arg->typeStartToken()->str() == "struct")
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checkStruct(tok, *arg);
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else if (arg->typeStartToken()->isStandardType()) {
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Alloc alloc = NO_ALLOC;
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checkScopeForVariable(tok->next(), *arg, nullptr, nullptr, &alloc, "");
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}
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}
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}
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}
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}
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}
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}
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void CheckUninitVar::checkStruct(const Token *tok, const Variable &structvar)
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{
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const Token *typeToken = structvar.typeStartToken();
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if (typeToken->str() == "struct")
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typeToken = typeToken->next();
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const SymbolDatabase * symbolDatabase = _tokenizer->getSymbolDatabase();
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for (std::size_t j = 0U; j < symbolDatabase->classAndStructScopes.size(); ++j) {
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const Scope *scope2 = symbolDatabase->classAndStructScopes[j];
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if (scope2->className == typeToken->str() && scope2->numConstructors == 0U) {
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for (std::list<Variable>::const_iterator it = scope2->varlist.begin(); it != scope2->varlist.end(); ++it) {
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const Variable &var = *it;
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if (var.hasDefault() || var.isArray() || (!_tokenizer->isC() && var.isClass() && (!var.type() || var.type()->needInitialization != Type::True)))
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continue;
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// is the variable declared in a inner union?
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bool innerunion = false;
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for (std::list<Scope>::const_iterator it2 = symbolDatabase->scopeList.begin(); it2 != symbolDatabase->scopeList.end(); ++it2) {
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const Scope &innerScope = *it2;
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if (innerScope.type == Scope::eUnion && innerScope.nestedIn == scope2) {
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if (var.typeStartToken()->linenr() >= innerScope.classStart->linenr() &&
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var.typeStartToken()->linenr() <= innerScope.classEnd->linenr()) {
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innerunion = true;
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break;
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}
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}
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}
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if (!innerunion) {
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Alloc alloc = NO_ALLOC;
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const Token *tok2 = tok;
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if (tok->str() == "}")
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tok2 = tok2->next();
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checkScopeForVariable(tok2, structvar, nullptr, nullptr, &alloc, var.name());
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}
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}
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}
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}
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}
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static void conditionAlwaysTrueOrFalse(const Token *tok, const std::map<unsigned int, int> &variableValue, bool *alwaysTrue, bool *alwaysFalse)
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{
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assert(Token::simpleMatch(tok, "if ("));
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const Token *vartok = tok->tokAt(2);
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const bool NOT(vartok->str() == "!");
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if (NOT)
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vartok = vartok->next();
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while (Token::Match(vartok, "%name% . %name%"))
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vartok = vartok->tokAt(2);
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std::map<unsigned int, int>::const_iterator it = variableValue.find(vartok->varId());
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if (it == variableValue.end())
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return;
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// always true
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if (Token::Match(vartok, "%name% %oror%|)")) {
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if (NOT)
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*alwaysTrue = bool(it->second == 0);
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else
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*alwaysTrue = bool(it->second != 0);
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} else if (Token::Match(vartok, "%name% == %num% %or%|)")) {
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*alwaysTrue = bool(it->second == MathLib::toLongNumber(vartok->strAt(2)));
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} else if (Token::Match(vartok, "%name% != %num% %or%|)")) {
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*alwaysTrue = bool(it->second != MathLib::toLongNumber(vartok->strAt(2)));
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}
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// always false
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if (Token::Match(vartok, "%name% &&|)")) {
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if (NOT)
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*alwaysFalse = bool(it->second != 0);
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else
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*alwaysFalse = bool(it->second == 0);
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} else if (Token::Match(vartok, "%name% == %num% &&|)")) {
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*alwaysFalse = bool(it->second != MathLib::toLongNumber(vartok->strAt(2)));
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} else if (Token::Match(vartok, "%name% != %num% &&|)")) {
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*alwaysFalse = bool(it->second == MathLib::toLongNumber(vartok->strAt(2)));
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}
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}
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static bool isVariableUsed(const Token *tok, const Variable& var)
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{
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if (!tok)
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return false;
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if (tok->str() == "&" && !tok->astOperand2())
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return false;
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if (tok->isConstOp())
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return isVariableUsed(tok->astOperand1(),var) || isVariableUsed(tok->astOperand2(),var);
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return (tok->varId() == var.declarationId());
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}
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bool CheckUninitVar::checkScopeForVariable(const Token *tok, const Variable& var, bool * const possibleInit, bool * const noreturn, Alloc* const alloc, const std::string &membervar)
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{
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const bool suppressErrors(possibleInit && *possibleInit);
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const bool printDebug = _settings->debugwarnings;
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if (possibleInit)
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*possibleInit = false;
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unsigned int number_of_if = 0;
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if (var.declarationId() == 0U)
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return true;
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// variable values
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std::map<unsigned int, int> variableValue;
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static const int NOT_ZERO = (1<<30); // special variable value
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for (; tok; tok = tok->next()) {
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// End of scope..
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if (tok->str() == "}") {
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if (number_of_if && possibleInit)
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*possibleInit = true;
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// might be a noreturn function..
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if (_tokenizer->IsScopeNoReturn(tok)) {
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if (noreturn)
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*noreturn = true;
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return false;
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}
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break;
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}
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// Unconditional inner scope or try..
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if (tok->str() == "{" && Token::Match(tok->previous(), ";|{|}|try")) {
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if (checkScopeForVariable(tok->next(), var, possibleInit, noreturn, alloc, membervar))
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return true;
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tok = tok->link();
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continue;
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}
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// assignment with nonzero constant..
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if (Token::Match(tok->previous(), "[;{}] %var% = - %name% ;"))
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variableValue[tok->varId()] = NOT_ZERO;
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// Inner scope..
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else if (Token::simpleMatch(tok, "if (")) {
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bool alwaysTrue = false;
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bool alwaysFalse = false;
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conditionAlwaysTrueOrFalse(tok, variableValue, &alwaysTrue, &alwaysFalse);
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// initialization / usage in condition..
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if (!alwaysTrue && checkIfForWhileHead(tok->next(), var, suppressErrors, bool(number_of_if == 0), *alloc, membervar))
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return true;
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// checking if a not-zero variable is zero => bail out
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unsigned int condVarId = 0, condVarValue = 0;
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const Token *condVarTok = nullptr;
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if (Token::simpleMatch(tok, "if (") &&
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astIsVariableComparison(tok->next()->astOperand2(), "!=", "0", &condVarTok)) {
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std::map<unsigned int,int>::const_iterator it = variableValue.find(condVarTok->varId());
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if (it != variableValue.end() && it->second == NOT_ZERO)
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return true; // this scope is not fully analysed => return true
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else {
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condVarId = condVarTok->varId();
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condVarValue = NOT_ZERO;
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}
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}
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// goto the {
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tok = tok->next()->link()->next();
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if (!tok)
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break;
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if (tok->str() == "{") {
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bool possibleInitIf(number_of_if > 0 || suppressErrors);
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bool noreturnIf = false;
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const bool initif = !alwaysFalse && checkScopeForVariable(tok->next(), var, &possibleInitIf, &noreturnIf, alloc, membervar);
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// bail out for such code:
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// if (a) x=0; // conditional initialization
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// if (b) return; // cppcheck doesn't know if b can be false when a is false.
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// x++; // it's possible x is always initialized
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if (!alwaysTrue && noreturnIf && number_of_if > 0) {
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if (printDebug) {
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std::string condition;
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for (const Token *tok2 = tok->linkAt(-1); tok2 != tok; tok2 = tok2->next()) {
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condition += tok2->str();
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if (tok2->isName() && tok2->next()->isName())
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condition += ' ';
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}
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reportError(tok, Severity::debug, "debug", "bailout uninitialized variable checking for '" + var.name() + "'. can't determine if this condition can be false when previous condition is false: " + condition);
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}
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return true;
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}
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if (alwaysTrue && noreturnIf)
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return true;
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std::map<unsigned int, int> varValueIf;
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if (!alwaysFalse && !initif && !noreturnIf) {
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for (const Token *tok2 = tok; tok2 && tok2 != tok->link(); tok2 = tok2->next()) {
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if (Token::Match(tok2, "[;{}.] %name% = - %name% ;"))
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varValueIf[tok2->next()->varId()] = NOT_ZERO;
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else if (Token::Match(tok2, "[;{}.] %name% = %num% ;"))
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varValueIf[tok2->next()->varId()] = (int)MathLib::toLongNumber(tok2->strAt(3));
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}
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}
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if (initif && condVarId > 0U)
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variableValue[condVarId] = condVarValue ^ NOT_ZERO;
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// goto the }
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tok = tok->link();
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if (!Token::simpleMatch(tok, "} else {")) {
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if (initif || possibleInitIf) {
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++number_of_if;
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if (number_of_if >= 2)
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return true;
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}
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} else {
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// goto the {
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tok = tok->tokAt(2);
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bool possibleInitElse(number_of_if > 0 || suppressErrors);
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bool noreturnElse = false;
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const bool initelse = !alwaysTrue && checkScopeForVariable(tok->next(), var, &possibleInitElse, &noreturnElse, alloc, membervar);
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std::map<unsigned int, int> varValueElse;
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if (!alwaysTrue && !initelse && !noreturnElse) {
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for (const Token *tok2 = tok; tok2 && tok2 != tok->link(); tok2 = tok2->next()) {
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if (Token::Match(tok2, "[;{}.] %var% = - %name% ;"))
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varValueElse[tok2->next()->varId()] = NOT_ZERO;
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else if (Token::Match(tok2, "[;{}.] %var% = %num% ;"))
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varValueElse[tok2->next()->varId()] = (int)MathLib::toLongNumber(tok2->strAt(3));
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}
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}
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if (initelse && condVarId > 0U && !noreturnIf && !noreturnElse)
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variableValue[condVarId] = condVarValue;
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// goto the }
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tok = tok->link();
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if ((alwaysFalse || initif || noreturnIf) &&
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(alwaysTrue || initelse || noreturnElse))
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return true;
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if (initif || initelse || possibleInitElse)
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++number_of_if;
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if (!initif && !noreturnIf)
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variableValue.insert(varValueIf.begin(), varValueIf.end());
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if (!initelse && !noreturnElse)
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variableValue.insert(varValueElse.begin(), varValueElse.end());
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}
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}
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}
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// = { .. }
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else if (Token::simpleMatch(tok, "= {")) {
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// end token
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const Token *end = tok->next()->link();
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// If address of variable is taken in the block then bail out
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if (Token::findmatch(tok->tokAt(2), "& %varid%", end, var.declarationId()))
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return true;
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// Skip block
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tok = end;
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continue;
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}
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// skip sizeof / offsetof
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if (Token::Match(tok, "sizeof|typeof|offsetof|decltype ("))
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tok = tok->next()->link();
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// for/while..
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else if (Token::Match(tok, "for|while (") || Token::simpleMatch(tok, "do {")) {
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const bool forwhile = Token::Match(tok, "for|while (");
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// is variable initialized in for-head (don't report errors yet)?
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if (forwhile && checkIfForWhileHead(tok->next(), var, true, false, *alloc, membervar))
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return true;
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// goto the {
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const Token *tok2 = forwhile ? tok->next()->link()->next() : tok->next();
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if (tok2 && tok2->str() == "{") {
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bool init = checkLoopBody(tok2, var, *alloc, membervar, (number_of_if > 0) || suppressErrors);
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// variable is initialized in the loop..
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if (init)
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return true;
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// is variable used in for-head?
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bool initcond = false;
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if (!suppressErrors) {
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const Token *startCond = forwhile ? tok->next() : tok->next()->link()->tokAt(2);
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initcond = checkIfForWhileHead(startCond, var, false, bool(number_of_if == 0), *alloc, membervar);
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}
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// goto "}"
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tok = tok2->link();
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// do-while => goto ")"
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if (!forwhile) {
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// Assert that the tokens are '} while ('
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if (!Token::simpleMatch(tok, "} while (")) {
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if (printDebug)
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reportError(tok,Severity::debug,"","assertion failed '} while ('");
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break;
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}
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// Goto ')'
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tok = tok->linkAt(2);
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if (!tok)
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// bailout : invalid code / bad tokenizer
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break;
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if (initcond)
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// variable is initialized in while-condition
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return true;
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}
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}
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}
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// Unknown or unhandled inner scope
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else if (Token::simpleMatch(tok, ") {") || (Token::Match(tok, "%name% {") && tok->str() != "try")) {
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if (tok->str() == "struct" || tok->str() == "union") {
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tok = tok->linkAt(1);
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continue;
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}
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return true;
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}
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// bailout if there is ({
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if (Token::simpleMatch(tok, "( {")) {
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return true;
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}
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// bailout if there is assembler code or setjmp
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if (Token::Match(tok, "asm|setjmp (")) {
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return true;
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}
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|
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if (tok->str() == "?") {
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if (!tok->astOperand2())
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return true;
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const bool used1 = isVariableUsed(tok->astOperand2()->astOperand1(), var);
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const bool used0 = isVariableUsed(tok->astOperand2()->astOperand2(), var);
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const bool err = (number_of_if == 0) ? (used1 || used0) : (used1 && used0);
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if (err)
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uninitvarError(tok, var.nameToken()->str(), *alloc);
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// Todo: skip expression if there is no error
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return true;
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}
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|
|
if (Token::Match(tok, "return|break|continue|throw|goto")) {
|
|
if (noreturn)
|
|
*noreturn = true;
|
|
|
|
while (tok && tok->str() != ";") {
|
|
// variable is seen..
|
|
if (tok->varId() == var.declarationId()) {
|
|
if (!membervar.empty()) {
|
|
if (Token::Match(tok, "%name% . %name% ;|%cop%") && tok->strAt(2) == membervar)
|
|
uninitStructMemberError(tok, tok->str() + "." + membervar);
|
|
else
|
|
return true;
|
|
}
|
|
|
|
// Use variable
|
|
else if (!suppressErrors && isVariableUsage(tok, var.isPointer(), *alloc))
|
|
uninitvarError(tok, tok->str(), *alloc);
|
|
|
|
else
|
|
// assume that variable is assigned
|
|
return true;
|
|
}
|
|
|
|
else if (Token::Match(tok, "sizeof|typeof|offsetof|decltype ("))
|
|
tok = tok->linkAt(1);
|
|
|
|
else if (tok->str() == "?") {
|
|
if (!tok->astOperand2())
|
|
return true;
|
|
const bool used1 = isVariableUsed(tok->astOperand2()->astOperand1(), var);
|
|
const bool used0 = isVariableUsed(tok->astOperand2()->astOperand2(), var);
|
|
const bool err = (number_of_if == 0) ? (used1 || used0) : (used1 && used0);
|
|
if (err)
|
|
uninitvarError(tok, var.nameToken()->str(), *alloc);
|
|
return true;
|
|
}
|
|
|
|
tok = tok->next();
|
|
}
|
|
|
|
return bool(noreturn==nullptr);
|
|
}
|
|
|
|
// variable is seen..
|
|
if (tok->varId() == var.declarationId()) {
|
|
// calling function that returns uninit data through pointer..
|
|
if (var.isPointer() &&
|
|
Token::Match(tok->next(), "= %name% (") &&
|
|
Token::simpleMatch(tok->linkAt(3), ") ;") &&
|
|
_settings->library.returnuninitdata.count(tok->strAt(2)) > 0U) {
|
|
*alloc = NO_CTOR_CALL;
|
|
continue;
|
|
}
|
|
if (var.isPointer() && (var.typeStartToken()->isStandardType() || (var.type() && var.type()->needInitialization == Type::True)) && Token::simpleMatch(tok->next(), "= new")) {
|
|
*alloc = CTOR_CALL;
|
|
if (var.typeScope() && var.typeScope()->numConstructors > 0)
|
|
return true;
|
|
continue;
|
|
}
|
|
|
|
|
|
if (!membervar.empty()) {
|
|
if (isMemberVariableAssignment(tok, membervar)) {
|
|
checkRhs(tok, var, *alloc, number_of_if, membervar);
|
|
return true;
|
|
}
|
|
|
|
if (isMemberVariableUsage(tok, var.isPointer(), *alloc, membervar))
|
|
uninitStructMemberError(tok, tok->str() + "." + membervar);
|
|
|
|
else if (Token::Match(tok->previous(), "[(,] %name% [,)]"))
|
|
return true;
|
|
|
|
} else {
|
|
// Use variable
|
|
if (!suppressErrors && isVariableUsage(tok, var.isPointer(), *alloc))
|
|
uninitvarError(tok, tok->str(), *alloc);
|
|
|
|
else {
|
|
if (tok->strAt(1) == "=")
|
|
checkRhs(tok, var, *alloc, number_of_if, "");
|
|
|
|
// assume that variable is assigned
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
bool CheckUninitVar::checkIfForWhileHead(const Token *startparentheses, const Variable& var, bool suppressErrors, bool isuninit, Alloc alloc, const std::string &membervar)
|
|
{
|
|
const Token * const endpar = startparentheses->link();
|
|
if (Token::Match(startparentheses, "( ! %name% %oror%") && startparentheses->tokAt(2)->getValue(0))
|
|
suppressErrors = true;
|
|
for (const Token *tok = startparentheses->next(); tok && tok != endpar; tok = tok->next()) {
|
|
if (tok->varId() == var.declarationId()) {
|
|
if (Token::Match(tok, "%name% . %name%")) {
|
|
if (tok->strAt(2) == membervar) {
|
|
if (isMemberVariableAssignment(tok, membervar))
|
|
return true;
|
|
|
|
if (!suppressErrors && isMemberVariableUsage(tok, var.isPointer(), alloc, membervar))
|
|
uninitStructMemberError(tok, tok->str() + "." + membervar);
|
|
}
|
|
continue;
|
|
}
|
|
|
|
if (isVariableUsage(tok, var.isPointer(), alloc)) {
|
|
if (suppressErrors)
|
|
continue;
|
|
uninitvarError(tok, tok->str(), alloc);
|
|
}
|
|
return true;
|
|
}
|
|
if (Token::Match(tok, "sizeof|decltype|offsetof ("))
|
|
tok = tok->next()->link();
|
|
if ((!isuninit || !membervar.empty()) && tok->str() == "&&")
|
|
suppressErrors = true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool CheckUninitVar::checkLoopBody(const Token *tok, const Variable& var, const Alloc alloc, const std::string &membervar, const bool suppressErrors)
|
|
{
|
|
const Token *usetok = nullptr;
|
|
|
|
assert(tok->str() == "{");
|
|
|
|
for (const Token * const end = tok->link(); tok != end; tok = tok->next()) {
|
|
if (tok->varId() == var.declarationId()) {
|
|
if (!membervar.empty()) {
|
|
if (isMemberVariableAssignment(tok, membervar)) {
|
|
bool assign = true;
|
|
bool rhs = false;
|
|
for (const Token *tok2 = tok->next(); tok2; tok2 = tok2->next()) {
|
|
if (tok2->str() == "=")
|
|
rhs = true;
|
|
if (tok2->str() == ";")
|
|
break;
|
|
if (rhs && tok2->varId() == var.declarationId() && isMemberVariableUsage(tok2, var.isPointer(), alloc, membervar)) {
|
|
assign = false;
|
|
break;
|
|
}
|
|
}
|
|
if (assign)
|
|
return true;
|
|
}
|
|
|
|
if (Token::Match(tok, "%name% ="))
|
|
return true;
|
|
|
|
if (isMemberVariableUsage(tok, var.isPointer(), alloc, membervar))
|
|
usetok = tok;
|
|
else if (Token::Match(tok->previous(), "[(,] %name% [,)]"))
|
|
return true;
|
|
} else {
|
|
if (isVariableUsage(tok, var.isPointer(), alloc))
|
|
usetok = tok;
|
|
else if (tok->strAt(1) == "=") {
|
|
// Is var used in rhs?
|
|
bool rhs = false;
|
|
std::stack<const Token *> tokens;
|
|
tokens.push(tok->next()->astOperand2());
|
|
while (!tokens.empty()) {
|
|
const Token *t = tokens.top();
|
|
tokens.pop();
|
|
if (!t)
|
|
continue;
|
|
if (t->varId() == var.declarationId()) {
|
|
// var is used in rhs
|
|
rhs = true;
|
|
break;
|
|
}
|
|
if (Token::simpleMatch(t->previous(),"sizeof ("))
|
|
continue;
|
|
tokens.push(t->astOperand1());
|
|
tokens.push(t->astOperand2());
|
|
}
|
|
if (!rhs)
|
|
return true;
|
|
} else {
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (Token::Match(tok, "sizeof|typeof ("))
|
|
tok = tok->next()->link();
|
|
|
|
if (Token::Match(tok, "asm ( %str% ) ;"))
|
|
return true;
|
|
}
|
|
|
|
if (!suppressErrors && usetok) {
|
|
if (membervar.empty())
|
|
uninitvarError(usetok, usetok->str(), alloc);
|
|
else
|
|
uninitStructMemberError(usetok, usetok->str() + "." + membervar);
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
void CheckUninitVar::checkRhs(const Token *tok, const Variable &var, Alloc alloc, unsigned int number_of_if, const std::string &membervar)
|
|
{
|
|
bool rhs = false;
|
|
unsigned int indent = 0;
|
|
while (nullptr != (tok = tok->next())) {
|
|
if (tok->str() == "=")
|
|
rhs = true;
|
|
else if (rhs && tok->varId() == var.declarationId()) {
|
|
if (membervar.empty() && isVariableUsage(tok, var.isPointer(), alloc))
|
|
uninitvarError(tok, tok->str(), alloc);
|
|
else if (!membervar.empty() && isMemberVariableUsage(tok, var.isPointer(), alloc, membervar))
|
|
uninitStructMemberError(tok, tok->str() + "." + membervar);
|
|
|
|
} else if (tok->str() == ";" || (indent==0 && tok->str() == ","))
|
|
break;
|
|
else if (tok->str() == "(")
|
|
++indent;
|
|
else if (tok->str() == ")") {
|
|
if (indent == 0)
|
|
break;
|
|
--indent;
|
|
} else if (tok->str() == "?" && tok->astOperand2()) {
|
|
const bool used1 = isVariableUsed(tok->astOperand2()->astOperand1(), var);
|
|
const bool used0 = isVariableUsed(tok->astOperand2()->astOperand2(), var);
|
|
const bool err = (number_of_if == 0) ? (used1 || used0) : (used1 && used0);
|
|
if (err)
|
|
uninitvarError(tok, var.nameToken()->str(), alloc);
|
|
break;
|
|
} else if (Token::simpleMatch(tok, "sizeof ("))
|
|
tok = tok->next()->link();
|
|
}
|
|
}
|
|
|
|
bool CheckUninitVar::isVariableUsage(const Token *vartok, bool pointer, Alloc alloc) const
|
|
{
|
|
if (alloc == NO_ALLOC && ((Token::Match(vartok->previous(), "return|delete") && vartok->strAt(1) != "=") || (vartok->strAt(-1) == "]" && vartok->linkAt(-1)->strAt(-1) == "delete")))
|
|
return true;
|
|
|
|
// Passing variable to typeof/__alignof__
|
|
if (Token::Match(vartok->tokAt(-3), "typeof|__alignof__ ( * %name%"))
|
|
return false;
|
|
|
|
// Accessing Rvalue member using "." or "->"
|
|
if (vartok->strAt(1) == "." && vartok->strAt(-1) != "&") {
|
|
// Is struct member passed to function?
|
|
if (!pointer && Token::Match(vartok->previous(), "[,(] %name% . %name%")) {
|
|
// TODO: there are FN currently:
|
|
// - should only return false if struct member is (or might be) array.
|
|
// - should only return false if function argument is (or might be) non-const pointer or reference
|
|
const Token *tok2 = vartok->next();
|
|
do {
|
|
tok2 = tok2->tokAt(2);
|
|
} while (Token::Match(tok2, ". %name%"));
|
|
if (Token::Match(tok2, "[,)]"))
|
|
return false;
|
|
} else if (pointer && alloc != CTOR_CALL && Token::Match(vartok, "%name% . %name% (")) {
|
|
return true;
|
|
}
|
|
|
|
bool assignment = false;
|
|
const Token* parent = vartok->astParent();
|
|
while (parent) {
|
|
if (parent->str() == "=") {
|
|
assignment = true;
|
|
break;
|
|
}
|
|
if (alloc != NO_ALLOC && parent->str() == "(") {
|
|
if (_settings->library.functionpure.find(parent->strAt(-1)) == _settings->library.functionpure.end()) {
|
|
assignment = true;
|
|
break;
|
|
}
|
|
}
|
|
parent = parent->astParent();
|
|
}
|
|
if (!assignment)
|
|
return true;
|
|
}
|
|
|
|
// Passing variable to function..
|
|
if (Token::Match(vartok->previous(), "[(,] %name% [,)]") || Token::Match(vartok->tokAt(-2), "[(,] & %name% [,)]")) {
|
|
const int use = isFunctionParUsage(vartok, pointer, alloc);
|
|
if (use >= 0)
|
|
return (use>0);
|
|
}
|
|
|
|
if (Token::Match(vartok->previous(), "++|--|%cop%")) {
|
|
if (_tokenizer->isCPP() && Token::Match(vartok->previous(), ">>|<<")) {
|
|
const Token* tok2 = vartok->previous();
|
|
if (Token::simpleMatch(tok2->astOperand1(), ">>"))
|
|
return false; // Looks like stream operator, initializes the variable
|
|
if (Token::simpleMatch(tok2, "<<")) {
|
|
// Looks like stream operator, but could also initialize the variable. Check lhs.
|
|
do {
|
|
tok2 = tok2->astOperand1();
|
|
} while (Token::simpleMatch(tok2, "<<"));
|
|
if (tok2 && tok2->strAt(-1) == "::")
|
|
tok2 = tok2->previous();
|
|
if (tok2 && (Token::simpleMatch(tok2->previous(), "std ::") || (tok2->variable() && tok2->variable()->isStlType()) || tok2->isStandardType()))
|
|
return true;
|
|
}
|
|
const Variable *var = vartok->tokAt(-2)->variable();
|
|
return (var && var->typeStartToken()->isStandardType());
|
|
}
|
|
|
|
// is there something like: ; "*((&var ..expr.. =" => the variable is assigned
|
|
if (vartok->previous()->str() == "&" && !vartok->previous()->astOperand2())
|
|
return false;
|
|
|
|
// bailout to avoid fp for 'int x = 2 + x();' where 'x()' is a unseen preprocessor macro (seen in linux)
|
|
if (!pointer && vartok->next() && vartok->next()->str() == "(")
|
|
return false;
|
|
|
|
if (vartok->previous()->str() != "&" || !Token::Match(vartok->tokAt(-2), "[(,=?:]")) {
|
|
if (alloc != NO_ALLOC && vartok->previous()->str() == "*") {
|
|
const Token *parent = vartok->previous()->astParent();
|
|
if (parent && parent->str() == "=" && parent->astOperand1() == vartok->previous())
|
|
return false;
|
|
return true;
|
|
}
|
|
return alloc == NO_ALLOC;
|
|
}
|
|
}
|
|
|
|
if (alloc == NO_ALLOC && Token::Match(vartok->previous(), "= %name% ;|%cop%"))
|
|
return true;
|
|
|
|
if (Token::Match(vartok->previous(), "? %name%")) {
|
|
// this is only variable usage if variable is either:
|
|
// * unconditionally uninitialized
|
|
// * used in both rhs and lhs of ':' operator
|
|
bool rhs = false;
|
|
for (const Token *tok2 = vartok; tok2; tok2 = tok2->next()) {
|
|
if (tok2->str() == "(")
|
|
tok2 = tok2->link();
|
|
else if (tok2->str() == ":")
|
|
rhs = true;
|
|
else if (Token::Match(tok2, "[)];,{}=]"))
|
|
break;
|
|
else if (rhs && tok2->varId() == vartok->varId())
|
|
return true;
|
|
}
|
|
}
|
|
|
|
bool unknown = false;
|
|
if (pointer && CheckNullPointer::isPointerDeRef(vartok, unknown)) {
|
|
// pointer is allocated - dereferencing it is ok.
|
|
if (alloc != NO_ALLOC)
|
|
return false;
|
|
|
|
// function parameter?
|
|
bool functionParameter = false;
|
|
if (Token::Match(vartok->tokAt(-2), "%name% (") || vartok->previous()->str() == ",")
|
|
functionParameter = true;
|
|
|
|
// if this is not a function parameter report this dereference as variable usage
|
|
if (!functionParameter)
|
|
return true;
|
|
}
|
|
|
|
if (_tokenizer->isCPP() && Token::Match(vartok->next(), "<<|>>")) {
|
|
// Is this calculation done in rhs?
|
|
const Token *tok = vartok;
|
|
while (tok && Token::Match(tok, "%name%|.|::"))
|
|
tok = tok->previous();
|
|
if (Token::Match(tok, "[;{}]"))
|
|
return false;
|
|
|
|
// Is variable a known POD type then this is a variable usage,
|
|
// otherwise we assume it's not.
|
|
const Variable *var = vartok->variable();
|
|
return (var && var->typeStartToken()->isStandardType());
|
|
}
|
|
|
|
if (alloc == NO_ALLOC && vartok->next() && vartok->next()->isOp() && !vartok->next()->isAssignmentOp())
|
|
return true;
|
|
|
|
if (vartok->strAt(1) == "]")
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
/***
|
|
* Is function parameter "used" so a "usage of uninitialized variable" can
|
|
* be written? If parameter is passed "by value" then it is "used". If it
|
|
* is passed "by reference" then it is not necessarily "used".
|
|
* @return -1 => unknown 0 => not used 1 => used
|
|
*/
|
|
int CheckUninitVar::isFunctionParUsage(const Token *vartok, bool pointer, Alloc alloc) const
|
|
{
|
|
if (!Token::Match(vartok->previous(), "[(,]") && !Token::Match(vartok->tokAt(-2), "[(,] &"))
|
|
return -1;
|
|
|
|
// locate start parentheses in function call..
|
|
unsigned int argumentNumber = 0;
|
|
const Token *start = vartok;
|
|
while (start && !Token::Match(start, "[;{}(]")) {
|
|
if (start->str() == ")")
|
|
start = start->link();
|
|
else if (start->str() == ",")
|
|
++argumentNumber;
|
|
start = start->previous();
|
|
}
|
|
|
|
// is this a function call?
|
|
if (start && Token::Match(start->previous(), "%name% (")) {
|
|
const bool address(vartok->previous()->str() == "&");
|
|
const bool array(vartok->variable() && vartok->variable()->isArray());
|
|
// check how function handle uninitialized data arguments..
|
|
const Function *func = start->previous()->function();
|
|
if (func) {
|
|
const Variable *arg = func->getArgumentVar(argumentNumber);
|
|
if (arg) {
|
|
const Token *argStart = arg->typeStartToken();
|
|
if (!address && !array && Token::Match(argStart, "struct| %type% %name%| [,)]"))
|
|
return 1;
|
|
if (pointer && !address && alloc == NO_ALLOC && Token::Match(argStart, "struct| %type% * %name% [,)]"))
|
|
return 1;
|
|
while (argStart->previous() && argStart->previous()->isName())
|
|
argStart = argStart->previous();
|
|
if (Token::Match(argStart, "const %type% & %name% [,)]"))
|
|
return 1;
|
|
if ((pointer || address) && alloc == NO_ALLOC && Token::Match(argStart, "const struct| %type% * %name% [,)]"))
|
|
return 1;
|
|
if ((pointer || address) && Token::Match(argStart, "const %type% %name% [") && Token::Match(argStart->linkAt(3), "] [,)]"))
|
|
return 1;
|
|
}
|
|
|
|
} else if (Token::Match(start->previous(), "if|while|for")) {
|
|
// control-flow statement reading the variable "by value"
|
|
return alloc == NO_ALLOC;
|
|
} else {
|
|
const bool isnullbad = _settings->library.isnullargbad(start->previous(), argumentNumber + 1);
|
|
if (pointer && !address && isnullbad && alloc == NO_ALLOC)
|
|
return true;
|
|
const bool isuninitbad = _settings->library.isuninitargbad(start->previous(), argumentNumber + 1);
|
|
if (alloc != NO_ALLOC)
|
|
return isnullbad && isuninitbad;
|
|
return isuninitbad && (!address || isnullbad);
|
|
}
|
|
}
|
|
|
|
// unknown
|
|
return -1;
|
|
}
|
|
|
|
bool CheckUninitVar::isMemberVariableAssignment(const Token *tok, const std::string &membervar) const
|
|
{
|
|
if (Token::Match(tok, "%name% . %name%") && tok->strAt(2) == membervar) {
|
|
if (Token::Match(tok->tokAt(3), "[=.[]"))
|
|
return true;
|
|
else if (Token::Match(tok->tokAt(-2), "[(,=] &"))
|
|
return true;
|
|
else if (Token::Match(tok->tokAt(-2), "%name% >>") && Token::Match(tok->tokAt(3), ";|>>")) // #6680
|
|
return true;
|
|
else if ((tok->previous() && tok->previous()->isConstOp()) || Token::Match(tok->previous(), "[|="))
|
|
; // member variable usage
|
|
else if (tok->tokAt(3)->isConstOp())
|
|
; // member variable usage
|
|
else if (Token::Match(tok->previous(), "[(,] %name% . %name% [,)]") &&
|
|
1 == isFunctionParUsage(tok, false, NO_ALLOC)) {
|
|
return false;
|
|
} else
|
|
return true;
|
|
} else if (tok->strAt(1) == "=")
|
|
return true;
|
|
else if (tok->strAt(-1) == "&") {
|
|
if (Token::Match(tok->tokAt(-2), "[(,] & %name%")) {
|
|
// locate start parentheses in function call..
|
|
unsigned int argumentNumber = 0;
|
|
const Token *ftok = tok;
|
|
while (ftok && !Token::Match(ftok, "[;{}(]")) {
|
|
if (ftok->str() == ")")
|
|
ftok = ftok->link();
|
|
else if (ftok->str() == ",")
|
|
++argumentNumber;
|
|
ftok = ftok->previous();
|
|
}
|
|
|
|
// is this a function call?
|
|
ftok = ftok ? ftok->previous() : NULL;
|
|
if (Token::Match(ftok, "%name% (")) {
|
|
// check how function handle uninitialized data arguments..
|
|
const Function *function = ftok->function();
|
|
const Variable *arg = function ? function->getArgumentVar(argumentNumber) : NULL;
|
|
const Token *argStart = arg ? arg->typeStartToken() : NULL;
|
|
while (argStart && argStart->previous() && argStart->previous()->isName())
|
|
argStart = argStart->previous();
|
|
if (Token::Match(argStart, "const struct| %type% * const| %name% [,)]"))
|
|
return false;
|
|
}
|
|
|
|
else if (ftok && Token::simpleMatch(ftok->previous(), "= * ("))
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool CheckUninitVar::isMemberVariableUsage(const Token *tok, bool isPointer, Alloc alloc, const std::string &membervar) const
|
|
{
|
|
if (Token::Match(tok->previous(), "[(,] %name% . %name% [,)]") &&
|
|
tok->strAt(2) == membervar) {
|
|
int use = isFunctionParUsage(tok, isPointer, alloc);
|
|
if (use == 1)
|
|
return true;
|
|
}
|
|
|
|
if (isMemberVariableAssignment(tok, membervar))
|
|
return false;
|
|
|
|
if (Token::Match(tok, "%name% . %name%") && tok->strAt(2) == membervar && !(tok->tokAt(-2)->variable() && tok->tokAt(-2)->variable()->isReference()))
|
|
return true;
|
|
else if (!isPointer && Token::Match(tok->previous(), "[(,] %name% [,)]") && isVariableUsage(tok, isPointer, alloc))
|
|
return true;
|
|
|
|
else if (!isPointer && Token::Match(tok->previous(), "= %name% ;"))
|
|
return true;
|
|
|
|
// = *(&var);
|
|
else if (!isPointer &&
|
|
Token::simpleMatch(tok->astParent(),"&") &&
|
|
Token::simpleMatch(tok->astParent()->astParent(),"*") &&
|
|
Token::Match(tok->astParent()->astParent()->astParent(), "= * (| &") &&
|
|
tok->astParent()->astParent()->astParent()->astOperand2() == tok->astParent()->astParent())
|
|
return true;
|
|
|
|
else if (_settings->experimental &&
|
|
!isPointer &&
|
|
Token::Match(tok->tokAt(-2), "[(,] & %name% [,)]") &&
|
|
isVariableUsage(tok, isPointer, alloc))
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
void CheckUninitVar::uninitstringError(const Token *tok, const std::string &varname, bool strncpy_)
|
|
{
|
|
reportError(tok, Severity::error, "uninitstring", "Dangerous usage of '" + varname + "'" + (strncpy_ ? " (strncpy doesn't always null-terminate it)." : " (not null-terminated)."));
|
|
}
|
|
|
|
void CheckUninitVar::uninitdataError(const Token *tok, const std::string &varname)
|
|
{
|
|
reportError(tok, Severity::error, "uninitdata", "Memory is allocated but not initialized: " + varname);
|
|
}
|
|
|
|
void CheckUninitVar::uninitvarError(const Token *tok, const std::string &varname)
|
|
{
|
|
reportError(tok, Severity::error, "uninitvar", "Uninitialized variable: " + varname);
|
|
}
|
|
|
|
void CheckUninitVar::uninitStructMemberError(const Token *tok, const std::string &membername)
|
|
{
|
|
reportError(tok,
|
|
Severity::error,
|
|
"uninitStructMember",
|
|
"Uninitialized struct member: " + membername);
|
|
}
|
|
|
|
void CheckUninitVar::deadPointer()
|
|
{
|
|
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
|
|
std::list<Scope>::const_iterator scope;
|
|
|
|
// check every executable scope
|
|
for (scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {
|
|
if (!scope->isExecutable())
|
|
continue;
|
|
// Dead pointers..
|
|
for (const Token* tok = scope->classStart; tok != scope->classEnd; tok = tok->next()) {
|
|
if (tok->variable() &&
|
|
tok->variable()->isPointer() &&
|
|
isVariableUsage(tok, true, NO_ALLOC)) {
|
|
const Token *alias = tok->getValueTokenDeadPointer();
|
|
if (alias) {
|
|
deadPointerError(tok,alias);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckUninitVar::deadPointerError(const Token *pointer, const Token *alias)
|
|
{
|
|
const std::string strpointer(pointer ? pointer->str() : std::string("pointer"));
|
|
const std::string stralias(alias ? alias->expressionString() : std::string("&x"));
|
|
|
|
reportError(pointer,
|
|
Severity::error,
|
|
"deadpointer",
|
|
"Dead pointer usage. Pointer '" + strpointer + "' is dead if it has been assigned '" + stralias + "' at line " + MathLib::toString(alias ? alias->linenr() : 0U) + ".");
|
|
}
|