ba037837c9
This will now warn when doing something like this:
```cpp
template <class T, class K, class V>
const V& get_default(const T& t, const K& k, const V& v) {
auto it = t.find(k);
if (it == t.end()) return v;
return it->second;
}
const int& bar(const std::unordered_map<int, int>& m, int k) {
auto x = 0;
return get_default(m, k, x);
}
```
The lifetime warning is considered inconclusive in this case.
I also updated valueflow to no tinject inconclusive values unless `--inconclusive` flag is passed. This creates some false negatives because library functions are not configured to not modify their input parameters, and there are some checks that do not check if the value is inconclusive or not.
132 lines
5.2 KiB
C++
132 lines
5.2 KiB
C++
/*
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* Cppcheck - A tool for static C/C++ code analysis
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* Copyright (C) 2007-2019 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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#ifndef checkautovariablesH
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#define checkautovariablesH
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//---------------------------------------------------------------------------
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#include "check.h"
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#include "config.h"
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#include <string>
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class ErrorLogger;
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class Settings;
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class Token;
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class Tokenizer;
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/// @addtogroup Checks
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/** @brief Various small checks for automatic variables */
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/// @{
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class CPPCHECKLIB CheckAutoVariables : public Check {
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public:
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/** This constructor is used when registering the CheckClass */
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CheckAutoVariables() : Check(myName()) {
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}
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/** This constructor is used when running checks. */
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CheckAutoVariables(const Tokenizer *tokenizer, const Settings *settings, ErrorLogger *errorLogger)
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: Check(myName(), tokenizer, settings, errorLogger) {
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}
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/** @brief Run checks against the normal token list */
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void runChecks(const Tokenizer *tokenizer, const Settings *settings, ErrorLogger *errorLogger) OVERRIDE {
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CheckAutoVariables checkAutoVariables(tokenizer, settings, errorLogger);
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checkAutoVariables.assignFunctionArg();
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checkAutoVariables.returnReference();
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checkAutoVariables.checkVarLifetime();
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checkAutoVariables.autoVariables();
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}
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/** assign function argument */
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void assignFunctionArg();
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/** Check auto variables */
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void autoVariables();
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/** Returning reference to local/temporary variable */
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void returnReference();
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void checkVarLifetime();
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void checkVarLifetimeScope(const Token * start, const Token * end);
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private:
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/**
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* Returning a temporary object?
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* @param tok pointing at the "return" token
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* @return true if a temporary object is returned
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*/
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static bool returnTemporary(const Token *tok);
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void errorReturnAddressToAutoVariable(const Token *tok);
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void errorReturnAddressToAutoVariable(const Token *tok, const ValueFlow::Value *value);
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void errorReturnPointerToLocalArray(const Token *tok);
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void errorAutoVariableAssignment(const Token *tok, bool inconclusive);
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void errorReturnDanglingLifetime(const Token *tok, const ValueFlow::Value* val);
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void errorInvalidLifetime(const Token *tok, const ValueFlow::Value* val);
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void errorDanglngLifetime(const Token *tok, const ValueFlow::Value *val);
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void errorReturnReference(const Token* tok, ErrorPath errorPath, bool inconclusive);
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void errorDanglingReference(const Token *tok, const Variable *var, ErrorPath errorPath);
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void errorReturnTempReference(const Token *tok);
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void errorInvalidDeallocation(const Token *tok, const ValueFlow::Value *val);
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void errorReturnAddressOfFunctionParameter(const Token *tok, const std::string &varname);
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void errorUselessAssignmentArg(const Token *tok);
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void errorUselessAssignmentPtrArg(const Token *tok);
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void getErrorMessages(ErrorLogger *errorLogger, const Settings *settings) const OVERRIDE {
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ErrorPath errorPath;
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CheckAutoVariables c(nullptr,settings,errorLogger);
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c.errorAutoVariableAssignment(nullptr, false);
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c.errorReturnAddressToAutoVariable(nullptr);
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c.errorReturnPointerToLocalArray(nullptr);
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c.errorReturnReference(nullptr, errorPath, false);
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c.errorDanglingReference(nullptr, nullptr, errorPath);
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c.errorReturnTempReference(nullptr);
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c.errorInvalidDeallocation(nullptr, nullptr);
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c.errorReturnAddressOfFunctionParameter(nullptr, "parameter");
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c.errorUselessAssignmentArg(nullptr);
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c.errorUselessAssignmentPtrArg(nullptr);
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c.errorReturnDanglingLifetime(nullptr, nullptr);
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c.errorInvalidLifetime(nullptr, nullptr);
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c.errorDanglngLifetime(nullptr, nullptr);
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}
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static std::string myName() {
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return "Auto Variables";
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}
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std::string classInfo() const OVERRIDE {
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return "A pointer to a variable is only valid as long as the variable is in scope.\n"
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"Check:\n"
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"- returning a pointer to auto or temporary variable\n"
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"- assigning address of an variable to an effective parameter of a function\n"
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"- returning reference to local/temporary variable\n"
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"- returning address of function parameter\n"
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"- suspicious assignment of pointer argument\n"
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"- useless assignment of function argument\n";
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}
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};
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/// @}
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//---------------------------------------------------------------------------
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#endif // checkautovariablesH
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