372 lines
12 KiB
C++
372 lines
12 KiB
C++
/*
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* Cppcheck - A tool for static C/C++ code analysis
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* Copyright (C) 2007-2011 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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// Auto variables checks
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//---------------------------------------------------------------------------
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#include "checkautovariables.h"
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#include "symboldatabase.h"
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#include <sstream>
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#include <iostream>
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#include <string>
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//---------------------------------------------------------------------------
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// Register this check class into cppcheck by creating a static instance of it..
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namespace
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{
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static CheckAutoVariables instance;
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}
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bool CheckAutoVariables::errorAv(const Token* left, const Token* right)
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{
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const Variable *var = _tokenizer->getSymbolDatabase()->getVariableFromVarId(left->varId());
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if (!var || !var->isArgument() ||
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(!var->isArray() && !Token::Match(var->nameToken()->tokAt(-3), "%type% * *")) ||
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(var->isArray() && !Token::Match(var->nameToken()->tokAt(-2), "%type% *")))
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return false;
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return isAutoVar(right->varId());
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}
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bool CheckAutoVariables::isAutoVar(unsigned int varId)
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{
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const Variable *var = _tokenizer->getSymbolDatabase()->getVariableFromVarId(varId);
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if (!var || !var->isLocal() || var->isStatic() || var->isArray() || var->typeEndToken()->str() == "*")
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return false;
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return true;
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}
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bool CheckAutoVariables::isAutoVarArray(unsigned int varId)
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{
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const Variable *var = _tokenizer->getSymbolDatabase()->getVariableFromVarId(varId);
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if (!var || !var->isLocal() || var->isStatic() || !var->isArray())
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return false;
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return true;
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}
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void CheckAutoVariables::autoVariables()
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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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for (scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope)
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{
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// only check functions
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if (scope->type != Scope::eFunction)
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continue;
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unsigned int indentlevel = 0;
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for (const Token *tok = scope->classDef->next()->link(); tok; tok = tok->next())
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{
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// indentlevel..
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if (tok->str() == "{")
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++indentlevel;
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else if (tok->str() == "}")
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{
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if (indentlevel <= 1)
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break;
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--indentlevel;
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}
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//Critical assignment
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if (Token::Match(tok, "[;{}] * %var% = & %var%") && errorAv(tok->tokAt(2), tok->tokAt(5)))
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{
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const Variable * var = symbolDatabase->getVariableFromVarId(tok->tokAt(5)->varId());
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if (var && (!var->isClass() || var->type()))
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errorAutoVariableAssignment(tok);
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}
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else if (Token::Match(tok, "[;{}] * %var% = %var% ;"))
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{
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const Variable * var1 = symbolDatabase->getVariableFromVarId(tok->tokAt(2)->varId());
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if (var1 && var1->isArgument() && Token::Match(var1->nameToken()->tokAt(-3), "%type% * *"))
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{
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const Variable * var2 = symbolDatabase->getVariableFromVarId(tok->tokAt(4)->varId());
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if (var2 && var2->isLocal() && var2->isArray())
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errorAutoVariableAssignment(tok);
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}
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tok = tok->tokAt(4);
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}
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else if (Token::Match(tok, "[;{}] %var% [ %any% ] = & %var%") && errorAv(tok->tokAt(1), tok->tokAt(7)))
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{
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errorAutoVariableAssignment(tok);
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}
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// Critical return
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else if (Token::Match(tok, "return & %var% ;") && isAutoVar(tok->tokAt(2)->varId()))
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{
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reportError(tok, Severity::error, "autoVariables", "Return of the address of an auto-variable");
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}
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// Invalid pointer deallocation
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else if (Token::Match(tok, "free ( %var% ) ;") && isAutoVarArray(tok->tokAt(2)->varId()))
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{
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reportError(tok, Severity::error, "autoVariables", "Invalid deallocation");
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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 CheckAutoVariables::returnPointerToLocalArray()
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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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for (scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope)
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{
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// only check functions
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if (scope->type != Scope::eFunction)
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continue;
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const Token *tok = scope->classDef;
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// skip any qualification
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while (Token::Match(tok->tokAt(-2), "%type% ::"))
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tok = tok->tokAt(-2);
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// have we reached a function that returns a pointer
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if (Token::Match(tok->tokAt(-2), "%type% *"))
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{
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// go to the '('
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const Token *tok2 = scope->classDef->next();
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// go to the ')'
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tok2 = tok2->next()->link();
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unsigned int indentlevel = 0;
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for (; tok2; tok2 = tok2->next())
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{
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// indentlevel..
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if (tok2->str() == "{")
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++indentlevel;
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else if (tok2->str() == "}")
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{
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if (indentlevel <= 1)
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break;
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--indentlevel;
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}
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// Return pointer to local array variable..
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if (Token::Match(tok2, "return %var% ;"))
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{
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const unsigned int varid = tok2->next()->varId();
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const Variable *var = symbolDatabase->getVariableFromVarId(varid);
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if (var && var->isLocal() && !var->isStatic() && var->isArray())
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{
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errorReturnPointerToLocalArray(tok2);
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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 CheckAutoVariables::errorReturnPointerToLocalArray(const Token *tok)
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{
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reportError(tok, Severity::error, "returnLocalVariable", "Returning pointer to local array variable");
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}
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void CheckAutoVariables::errorAutoVariableAssignment(const Token *tok)
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{
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reportError(tok, Severity::error, "autoVariables",
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"Assigning address of local auto-variable to a function parameter.\n"
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"Dangerous assignment - function parameter takes the address of a local "
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"auto-variable. Local auto-variables are reserved from the stack. And the "
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"stack is freed when the function ends. So the pointer to a local variable "
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"is invalid after the function ends.");
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}
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//---------------------------------------------------------------------------
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// return temporary?
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bool CheckAutoVariables::returnTemporary(const Token *tok) const
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{
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if (!Token::Match(tok, "return %var% ("))
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return false;
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return bool(0 != Token::findmatch(_tokenizer->tokens(), ("std :: string " + tok->next()->str() + " (").c_str()));
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}
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//---------------------------------------------------------------------------
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void CheckAutoVariables::returnReference()
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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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for (scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope)
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{
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// only check functions
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if (scope->type != Scope::eFunction)
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continue;
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const Token *tok = scope->classDef;
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// skip any qualification
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while (Token::Match(tok->tokAt(-2), "%type% ::"))
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tok = tok->tokAt(-2);
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// have we reached a function that returns a reference?
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if (Token::Match(tok->tokAt(-2), "%type% &") ||
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Token::Match(tok->tokAt(-2), "> &"))
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{
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// go to the '('
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const Token *tok2 = scope->classDef->next();
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// go to the ')'
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tok2 = tok2->link();
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unsigned int indentlevel = 0;
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for (; tok2; tok2 = tok2->next())
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{
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// indentlevel..
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if (tok2->str() == "{")
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++indentlevel;
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else if (tok2->str() == "}")
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{
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if (indentlevel <= 1)
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break;
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--indentlevel;
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}
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// return..
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if (Token::Match(tok2, "return %var% ;"))
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{
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// is the returned variable a local variable?
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const unsigned int varid = tok2->next()->varId();
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const Variable *var = symbolDatabase->getVariableFromVarId(varid);
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if (var && var->isLocal() && !var->isStatic())
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{
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// report error..
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errorReturnReference(tok2);
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}
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}
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// return reference to temporary..
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else if (returnTemporary(tok2))
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{
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// report error..
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errorReturnTempReference(tok2);
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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 CheckAutoVariables::errorReturnReference(const Token *tok)
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{
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reportError(tok, Severity::error, "returnReference", "Returning reference to auto variable");
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}
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void CheckAutoVariables::errorReturnTempReference(const Token *tok)
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{
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reportError(tok, Severity::error, "returnTempReference", "Returning reference to temporary");
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}
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//---------------------------------------------------------------------------
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// Return c_str
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void CheckAutoVariables::returncstr()
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{
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// locate function that returns a const char *..
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const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
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std::list<Scope>::const_iterator scope;
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for (scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope)
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{
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// only check functions
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if (scope->type != Scope::eFunction)
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continue;
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const Token *tok = scope->classDef;
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// skip any qualification
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while (Token::Match(tok->tokAt(-2), "%type% ::"))
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tok = tok->tokAt(-2);
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// have we reached a function that returns a const char *
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if (Token::simpleMatch(tok->tokAt(-3), "const char *"))
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{
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// go to the '('
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const Token *tok2 = scope->classDef->next();
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// go to the ')'
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tok2 = tok2->next()->link();
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unsigned int indentlevel = 0;
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for (; tok2; tok2 = tok2->next())
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{
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// indentlevel..
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if (tok2->str() == "{")
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++indentlevel;
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else if (tok2->str() == "}")
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{
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if (indentlevel <= 1)
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break;
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--indentlevel;
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}
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// return..
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if (Token::Match(tok2, "return %var% . c_str ( ) ;"))
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{
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// is the returned variable a local variable?
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const unsigned int varid = tok2->next()->varId();
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const Variable *var = symbolDatabase->getVariableFromVarId(varid);
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if (var && var->isLocal() && !var->isStatic())
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{
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// report error..
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errorReturnAutocstr(tok2);
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}
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}
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// return pointer to temporary..
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else if (returnTemporary(tok2))
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{
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// report error..
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errorReturnTempPointer(tok2);
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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 CheckAutoVariables::errorReturnAutocstr(const Token *tok)
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{
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reportError(tok, Severity::error, "returnAutocstr", "Returning pointer to auto variable");
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}
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void CheckAutoVariables::errorReturnTempPointer(const Token *tok)
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{
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reportError(tok, Severity::error, "returnTempPointer", "Returning pointer to temporary");
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}
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