1064 lines
38 KiB
C++
1064 lines
38 KiB
C++
/*
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* Cppcheck - A tool for static C/C++ code analysis
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* Copyright (C) 2007-2012 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 "checkunusedvar.h"
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#include "symboldatabase.h"
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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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CheckUnusedVar instance;
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}
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/**
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* @brief This class is used create a list of variables within a function.
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*/
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class Variables {
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public:
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enum VariableType { standard, array, pointer, reference, pointerArray, referenceArray, pointerPointer, none };
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/** Store information about variable usage */
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class VariableUsage {
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public:
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VariableUsage(const Token *name = 0,
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VariableType type = standard,
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const Scope *scope = NULL,
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bool read = false,
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bool write = false,
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bool modified = false,
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bool allocateMemory = false) :
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_name(name),
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_type(type),
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_scope(scope),
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_read(read),
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_write(write),
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_modified(modified),
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_allocateMemory(allocateMemory) {
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}
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/** variable is used.. set both read+write */
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void use() {
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_read = true;
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_write = true;
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}
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/** is variable unused? */
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bool unused() const {
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return (_read == false && _write == false);
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}
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const Token *_name;
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VariableType _type;
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const Scope *_scope;
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bool _read;
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bool _write;
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bool _modified; // read/modify/write
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bool _allocateMemory;
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std::set<unsigned int> _aliases;
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std::set<const Scope*> _assignments;
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};
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typedef std::map<unsigned int, VariableUsage> VariableMap;
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void clear() {
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_varUsage.clear();
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}
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const VariableMap &varUsage() {
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return _varUsage;
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}
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void addVar(const Token *name, VariableType type, const Scope *scope, bool write_);
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void allocateMemory(unsigned int varid);
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void read(unsigned int varid);
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void readAliases(unsigned int varid);
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void readAll(unsigned int varid);
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void write(unsigned int varid);
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void writeAliases(unsigned int varid);
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void writeAll(unsigned int varid);
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void use(unsigned int varid);
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void modified(unsigned int varid);
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VariableUsage *find(unsigned int varid);
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void alias(unsigned int varid1, unsigned int varid2, bool replace);
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void erase(unsigned int varid) {
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_varUsage.erase(varid);
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}
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void eraseAliases(unsigned int varid);
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void eraseAll(unsigned int varid);
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void clearAliases(unsigned int varid);
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private:
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VariableMap _varUsage;
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};
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/**
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* Alias the 2 given variables. Either replace the existing aliases if
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* they exist or merge them. You would replace an existing alias when this
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* assignment is in the same scope as the previous assignment. You might
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* merge the aliases when this assignment is in a different scope from the
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* previous assignment depending on the relationship of the 2 scopes.
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*/
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void Variables::alias(unsigned int varid1, unsigned int varid2, bool replace)
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{
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VariableUsage *var1 = find(varid1);
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VariableUsage *var2 = find(varid2);
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// alias to self
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if (varid1 == varid2) {
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if (var1)
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var1->use();
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return;
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}
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if (replace) {
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// remove var1 from all aliases
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for (std::set<unsigned int>::iterator i = var1->_aliases.begin(); i != var1->_aliases.end(); ++i) {
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VariableUsage *temp = find(*i);
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if (temp)
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temp->_aliases.erase(var1->_name->varId());
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}
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// remove all aliases from var1
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var1->_aliases.clear();
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}
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// var1 gets all var2s aliases
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for (std::set<unsigned int>::iterator i = var2->_aliases.begin(); i != var2->_aliases.end(); ++i) {
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if (*i != varid1)
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var1->_aliases.insert(*i);
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}
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// var2 is an alias of var1
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var2->_aliases.insert(varid1);
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var1->_aliases.insert(varid2);
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if (var2->_type == Variables::pointer)
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var2->_read = true;
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}
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void Variables::clearAliases(unsigned int varid)
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{
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VariableUsage *usage = find(varid);
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if (usage) {
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// remove usage from all aliases
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std::set<unsigned int>::iterator i;
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for (i = usage->_aliases.begin(); i != usage->_aliases.end(); ++i) {
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VariableUsage *temp = find(*i);
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if (temp)
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temp->_aliases.erase(usage->_name->varId());
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}
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// remove all aliases from usage
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usage->_aliases.clear();
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}
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}
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void Variables::eraseAliases(unsigned int varid)
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{
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VariableUsage *usage = find(varid);
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if (usage) {
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std::set<unsigned int>::iterator aliases;
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for (aliases = usage->_aliases.begin(); aliases != usage->_aliases.end(); ++aliases)
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erase(*aliases);
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}
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}
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void Variables::eraseAll(unsigned int varid)
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{
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eraseAliases(varid);
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erase(varid);
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}
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void Variables::addVar(const Token *name,
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VariableType type,
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const Scope *scope,
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bool write_)
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{
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if (name->varId() > 0)
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_varUsage.insert(std::make_pair(name->varId(), VariableUsage(name, type, scope, false, write_, false)));
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}
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void Variables::allocateMemory(unsigned int varid)
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{
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VariableUsage *usage = find(varid);
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if (usage)
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usage->_allocateMemory = true;
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}
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void Variables::read(unsigned int varid)
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{
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VariableUsage *usage = find(varid);
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if (usage)
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usage->_read = true;
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}
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void Variables::readAliases(unsigned int varid)
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{
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VariableUsage *usage = find(varid);
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if (usage) {
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std::set<unsigned int>::iterator aliases;
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for (aliases = usage->_aliases.begin(); aliases != usage->_aliases.end(); ++aliases) {
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VariableUsage *aliased = find(*aliases);
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if (aliased)
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aliased->_read = true;
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}
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}
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}
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void Variables::readAll(unsigned int varid)
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{
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VariableUsage *usage = find(varid);
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if (usage) {
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usage->_read = true;
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std::set<unsigned int>::iterator aliases;
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for (aliases = usage->_aliases.begin(); aliases != usage->_aliases.end(); ++aliases) {
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VariableUsage *aliased = find(*aliases);
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if (aliased)
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aliased->_read = true;
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}
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}
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}
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void Variables::write(unsigned int varid)
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{
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VariableUsage *usage = find(varid);
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if (usage)
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usage->_write = true;
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}
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void Variables::writeAliases(unsigned int varid)
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{
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VariableUsage *usage = find(varid);
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if (usage) {
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std::set<unsigned int>::iterator aliases;
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for (aliases = usage->_aliases.begin(); aliases != usage->_aliases.end(); ++aliases) {
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VariableUsage *aliased = find(*aliases);
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if (aliased)
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aliased->_write = true;
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}
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}
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}
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void Variables::writeAll(unsigned int varid)
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{
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VariableUsage *usage = find(varid);
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if (usage) {
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usage->_write = true;
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std::set<unsigned int>::iterator aliases;
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for (aliases = usage->_aliases.begin(); aliases != usage->_aliases.end(); ++aliases) {
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VariableUsage *aliased = find(*aliases);
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if (aliased)
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aliased->_write = true;
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}
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}
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}
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void Variables::use(unsigned int varid)
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{
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VariableUsage *usage = find(varid);
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if (usage) {
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usage->use();
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std::set<unsigned int>::iterator aliases;
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for (aliases = usage->_aliases.begin(); aliases != usage->_aliases.end(); ++aliases) {
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VariableUsage *aliased = find(*aliases);
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if (aliased)
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aliased->use();
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}
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}
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}
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void Variables::modified(unsigned int varid)
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{
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VariableUsage *usage = find(varid);
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if (usage) {
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usage->_modified = true;
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std::set<unsigned int>::iterator aliases;
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for (aliases = usage->_aliases.begin(); aliases != usage->_aliases.end(); ++aliases) {
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VariableUsage *aliased = find(*aliases);
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if (aliased)
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aliased->_modified = true;
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}
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}
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}
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Variables::VariableUsage *Variables::find(unsigned int varid)
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{
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if (varid) {
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VariableMap::iterator i = _varUsage.find(varid);
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if (i != _varUsage.end())
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return &i->second;
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}
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return 0;
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}
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static int doAssignment(Variables &variables, const Token *tok, bool dereference, const Scope *scope)
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{
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// a = a + b;
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if (Token::Match(tok, "%var% = %var% !!;") && tok->str() == tok->strAt(2)) {
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return 2;
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}
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int next = 0;
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// check for aliased variable
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const unsigned int varid1 = tok->varId();
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Variables::VariableUsage *var1 = variables.find(varid1);
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if (var1) {
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Variables::VariableUsage *var2 = 0;
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int start = 1;
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// search for '='
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while (tok->strAt(start) != "=")
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start++;
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start++;
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if (Token::Match(tok->tokAt(start), "&| %var%") ||
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Token::Match(tok->tokAt(start), "( const| struct|union| %type% *| ) &| %var%") ||
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Token::Match(tok->tokAt(start), "( const| struct|union| %type% *| ) ( &| %var%") ||
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Token::Match(tok->tokAt(start+1), "< const| struct|union| %type% *| > ( &| %var%")) {
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unsigned char offset = 0;
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unsigned int varid2;
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bool addressOf = false;
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if (Token::Match(tok->tokAt(start), "%var% ."))
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variables.use(tok->tokAt(start)->varId()); // use = read + write
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// check for C style cast
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if (tok->strAt(start) == "(") {
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if (tok->strAt(start + 1) == "const")
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offset++;
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if (Token::Match(tok->tokAt(start + 1 + offset), "struct|union"))
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offset++;
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if (tok->strAt(start + 2 + offset) == "*")
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offset++;
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if (tok->strAt(start + 3 + offset) == "&") {
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addressOf = true;
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next = start + 4 + offset;
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} else if (tok->strAt(start + 3 + offset) == "(") {
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if (tok->strAt(start + 4 + offset) == "&") {
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addressOf = true;
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next = start + 5 + offset;
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} else
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next = start + 4 + offset;
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} else
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next = start + 3 + offset;
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}
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// check for C++ style cast
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else if (tok->strAt(start).find("cast") != std::string::npos &&
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tok->strAt(start + 1) == "<") {
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if (tok->strAt(start + 2) == "const")
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offset++;
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if (Token::Match(tok->tokAt(start + 2 + offset), "struct|union"))
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offset++;
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if (tok->strAt(start + 3 + offset) == "*")
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offset++;
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if (tok->strAt(start + 5 + offset) == "&") {
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addressOf = true;
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next = start + 6 + offset;
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} else
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next = start + 5 + offset;
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}
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// check for var ? ...
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else if (Token::Match(tok->tokAt(start), "%var% ?")) {
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next = start;
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}
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// no cast
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else {
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if (tok->strAt(start) == "&") {
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addressOf = true;
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next = start + 1;
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} else if (tok->strAt(start) == "new")
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return 0;
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else
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next = start;
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}
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// check if variable is local
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varid2 = tok->tokAt(next)->varId();
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var2 = variables.find(varid2);
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if (var2) { // local variable (alias or read it)
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if (var1->_type == Variables::pointer) {
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if (dereference)
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variables.read(varid2);
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else {
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if (addressOf ||
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var2->_type == Variables::array ||
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var2->_type == Variables::pointer) {
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bool replace = true;
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// check if variable declared in same scope
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if (scope == var1->_scope)
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replace = true;
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// not in same scope as declaration
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else {
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// no other assignment in this scope
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if (var1->_assignments.find(scope) == var1->_assignments.end()) {
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// nothing to replace
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if (var1->_assignments.empty())
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replace = false;
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// this variable has previous assignments
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else {
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/**
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* @todo determine if existing aliases should be replaced or merged
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*/
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replace = false;
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}
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}
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// assignment in this scope
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else {
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// replace when only one other assignment
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if (var1->_assignments.size() == 1)
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replace = true;
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// otherwise, merge them
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else
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replace = false;
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}
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}
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variables.alias(varid1, varid2, replace);
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} else if (tok->strAt(next + 1) == "?") {
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if (var2->_type == Variables::reference)
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variables.readAliases(varid2);
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else
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variables.read(varid2);
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}
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}
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} else if (var1->_type == Variables::reference) {
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variables.alias(varid1, varid2, true);
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} else {
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if (var2->_type == Variables::pointer && tok->strAt(next + 1) == "[")
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variables.readAliases(varid2);
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variables.read(varid2);
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}
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} else { // not a local variable (or an unsupported local variable)
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if (var1->_type == Variables::pointer && !dereference) {
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// check if variable declaration is in this scope
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if (var1->_scope == scope)
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variables.clearAliases(varid1);
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else {
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// no other assignment in this scope
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if (var1->_assignments.find(scope) == var1->_assignments.end()) {
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/**
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* @todo determine if existing aliases should be discarded
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*/
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}
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// this assignment replaces the last assignment in this scope
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else {
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// aliased variables in a larger scope are not supported
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// remove all aliases
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variables.clearAliases(varid1);
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}
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}
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}
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}
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}
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var1->_assignments.insert(scope);
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}
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// check for alias to struct member
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// char c[10]; a.b = c;
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else if (Token::Match(tok->tokAt(-2), "%var% .")) {
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if (Token::Match(tok->tokAt(2), "%var%")) {
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unsigned int varid2 = tok->tokAt(2)->varId();
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Variables::VariableUsage *var2 = variables.find(varid2);
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// struct member aliased to local variable
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if (var2 && (var2->_type == Variables::array ||
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var2->_type == Variables::pointer)) {
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// erase aliased variable and all variables that alias it
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// to prevent false positives
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variables.eraseAll(varid2);
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}
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}
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}
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return next;
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}
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static bool isRecordTypeWithoutSideEffects(const Variable& var)
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{
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// a type that has no side effects (no constructors and no members with constructors)
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/** @todo false negative: check base class for side effects */
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/** @todo false negative: check constructors for side effects */
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if (var.type() && var.type()->numConstructors == 0 &&
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(var.type()->varlist.empty() || var.type()->needInitialization == Scope::True) &&
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var.type()->derivedFrom.empty())
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return true;
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return false;
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}
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static bool isPartOfClassStructUnion(const Token* tok)
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{
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for (; tok; tok = tok->previous()) {
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if (tok->str() == "}" || tok->str() == ")")
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tok = tok->link();
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else if (tok->str() == "(")
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return(false);
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else if (tok->str() == "{") {
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return(tok->strAt(-1) == "struct" || tok->strAt(-2) == "struct" || tok->strAt(-1) == "class" || tok->strAt(-2) == "class" || tok->strAt(-1) == "union" || tok->strAt(-2) == "union");
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}
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}
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return false;
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}
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// Skip [ .. ]
|
|
static const Token * skipBrackets(const Token *tok)
|
|
{
|
|
while (tok && tok->str() == "[")
|
|
tok = tok->link()->next();
|
|
return tok;
|
|
}
|
|
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Usage of function variables
|
|
//---------------------------------------------------------------------------
|
|
void CheckUnusedVar::checkFunctionVariableUsage_iterateScopes(const Scope* const scope, Variables& variables)
|
|
{
|
|
if (scope->type == Scope::eClass || scope->type == Scope::eUnion || scope->type == Scope::eStruct)
|
|
return;
|
|
|
|
// Find declarations
|
|
for (std::list<Variable>::const_iterator i = scope->varlist.begin(); i != scope->varlist.end(); ++i) {
|
|
Variables::VariableType type = Variables::none;
|
|
if (i->isArray() && (i->nameToken()->previous()->str() == "*" || i->nameToken()->strAt(-2) == "*"))
|
|
type = Variables::pointerArray;
|
|
else if (i->isArray() && i->nameToken()->previous()->str() == "&")
|
|
type = Variables::referenceArray;
|
|
else if (i->isArray())
|
|
type = Variables::array;
|
|
else if (i->nameToken()->previous()->str() == "&")
|
|
type = Variables::reference;
|
|
else if (i->nameToken()->previous()->str() == "*" && i->nameToken()->strAt(-2) == "*")
|
|
type = Variables::pointerPointer;
|
|
else if (i->nameToken()->previous()->str() == "*" || i->nameToken()->strAt(-2) == "*")
|
|
type = Variables::pointer;
|
|
else if (i->typeEndToken()->isStandardType() || isRecordTypeWithoutSideEffects(*i) || Token::simpleMatch(i->nameToken()->tokAt(-3), "std :: string"))
|
|
type = Variables::standard;
|
|
if (type == Variables::none || isPartOfClassStructUnion(i->typeStartToken()))
|
|
continue;
|
|
const Token* defValTok = i->nameToken()->next();
|
|
for (; defValTok; defValTok = defValTok->next()) {
|
|
if (defValTok->str() == "[")
|
|
defValTok = defValTok->link();
|
|
else if (defValTok->str() == "(" || defValTok->str() == "=") {
|
|
variables.addVar(i->nameToken(), type, scope, true);
|
|
break;
|
|
} else if (defValTok->str() == ";" || defValTok->str() == "," || defValTok->str() == ")") {
|
|
variables.addVar(i->nameToken(), type, scope, i->isStatic());
|
|
break;
|
|
}
|
|
}
|
|
if (i->isArray() && Token::Match(i->nameToken(), "%var% [ %var% ]")) // Array index variable read.
|
|
variables.read(i->nameToken()->tokAt(2)->varId());
|
|
|
|
if (Token::simpleMatch(defValTok, "= {")) {
|
|
for (const Token* tok = defValTok; tok && tok != defValTok->linkAt(1); tok = tok->next())
|
|
if (Token::Match(tok, "%var%")) // Variables used to initialize the array read.
|
|
variables.read(tok->varId());
|
|
} else if (Token::Match(defValTok, "( %var% )")) // Variables used to initialize the variable read.
|
|
variables.readAll(defValTok->next()->varId()); // ReadAll?
|
|
else if (defValTok->str() == "=") {
|
|
doAssignment(variables, i->nameToken(), false, scope);
|
|
}
|
|
}
|
|
|
|
// Check variable usage
|
|
for (const Token *tok = scope->classDef->next(); tok && tok != scope->classEnd; tok = tok->next()) {
|
|
if (tok->str() == "for" || tok->str() == "catch") {
|
|
for (std::list<Scope*>::const_iterator i = scope->nestedList.begin(); i != scope->nestedList.end(); ++i) {
|
|
if ((*i)->classDef == tok) { // Find associated scope
|
|
checkFunctionVariableUsage_iterateScopes(*i, variables); // Scan child scope
|
|
tok = (*i)->classStart->link();
|
|
break;
|
|
}
|
|
}
|
|
if (!tok)
|
|
break;
|
|
}
|
|
if (tok->str() == "{") {
|
|
for (std::list<Scope*>::const_iterator i = scope->nestedList.begin(); i != scope->nestedList.end(); ++i) {
|
|
if ((*i)->classStart == tok) { // Find associated scope
|
|
checkFunctionVariableUsage_iterateScopes(*i, variables); // Scan child scope
|
|
tok = tok->link();
|
|
break;
|
|
}
|
|
}
|
|
if (!tok)
|
|
break;
|
|
}
|
|
|
|
if (Token::Match(tok, "asm ( %str% )")) {
|
|
variables.clear();
|
|
break;
|
|
}
|
|
|
|
if (Token::Match(tok, "%type% const| *|&| const| *| const| %var% [;=[(]") && tok->str() != "return" && tok->str() != "throw") { // Declaration: Skip
|
|
tok = tok->next();
|
|
while (Token::Match(tok, "const|*|&"))
|
|
tok = tok->next();
|
|
tok = Token::findmatch(tok, "[;=[(]");
|
|
if (tok && Token::Match(tok, "( %var% )")) // Simple initialization through copy ctor
|
|
tok = tok->next();
|
|
else if (tok && Token::Match(tok, "= %var% ;")) // Simple initialization
|
|
tok = tok->next();
|
|
if (!tok)
|
|
break;
|
|
}
|
|
// Freeing memory (not considered "using" the pointer if it was also allocated in this function)
|
|
if (Token::Match(tok, "free|g_free|kfree|vfree ( %var% )") ||
|
|
Token::Match(tok, "delete %var% ;") ||
|
|
Token::Match(tok, "delete [ ] %var% ;")) {
|
|
unsigned int varid = 0;
|
|
if (tok->str() != "delete") {
|
|
varid = tok->tokAt(2)->varId();
|
|
tok = tok->tokAt(3);
|
|
} else if (tok->strAt(1) == "[") {
|
|
varid = tok->tokAt(3)->varId();
|
|
tok = tok->tokAt(3);
|
|
} else {
|
|
varid = tok->next()->varId();
|
|
tok = tok->next();
|
|
}
|
|
|
|
Variables::VariableUsage *var = variables.find(varid);
|
|
if (var && !var->_allocateMemory) {
|
|
variables.readAll(varid);
|
|
}
|
|
}
|
|
|
|
else if (Token::Match(tok, "return|throw %var%")) {
|
|
for (const Token *tok2 = tok->next(); tok2; tok2 = tok2->next()) {
|
|
if (tok2->varId())
|
|
variables.readAll(tok2->varId());
|
|
else if (tok2->str() == ";")
|
|
break;
|
|
}
|
|
}
|
|
|
|
// assignment
|
|
else if (!Token::Match(tok->tokAt(-2), "[;{}.] %var% (") &&
|
|
(Token::Match(tok, "*| (| ++|--| %var% ++|--| )| =") ||
|
|
Token::Match(tok, "*| ( const| %type% *| ) %var% ="))) {
|
|
bool dereference = false;
|
|
bool pre = false;
|
|
bool post = false;
|
|
|
|
if (tok->str() == "*") {
|
|
dereference = true;
|
|
tok = tok->next();
|
|
}
|
|
|
|
if (Token::Match(tok, "( const| %type% *| ) %var% ="))
|
|
tok = tok->link()->next();
|
|
|
|
else if (tok->str() == "(")
|
|
tok = tok->next();
|
|
|
|
if (Token::Match(tok, "++|--")) {
|
|
pre = true;
|
|
tok = tok->next();
|
|
}
|
|
|
|
if (Token::Match(tok->next(), "++|--"))
|
|
post = true;
|
|
|
|
const unsigned int varid1 = tok->varId();
|
|
const Token *start = tok;
|
|
|
|
tok = tok->tokAt(doAssignment(variables, tok, dereference, scope));
|
|
|
|
if (pre || post)
|
|
variables.use(varid1);
|
|
|
|
if (dereference) {
|
|
Variables::VariableUsage *var = variables.find(varid1);
|
|
if (var && var->_type == Variables::array)
|
|
variables.write(varid1);
|
|
variables.writeAliases(varid1);
|
|
variables.read(varid1);
|
|
} else {
|
|
Variables::VariableUsage *var = variables.find(varid1);
|
|
if (var && var->_type == Variables::reference) {
|
|
variables.writeAliases(varid1);
|
|
variables.read(varid1);
|
|
}
|
|
// Consider allocating memory separately because allocating/freeing alone does not constitute using the variable
|
|
else if (var && var->_type == Variables::pointer &&
|
|
Token::Match(start, "%var% = new|malloc|calloc|g_malloc|kmalloc|vmalloc")) {
|
|
bool allocate = true;
|
|
|
|
if (start->strAt(2) == "new") {
|
|
const Token *type = start->tokAt(3);
|
|
|
|
// skip nothrow
|
|
if (Token::simpleMatch(type, "( nothrow )") ||
|
|
Token::simpleMatch(type, "( std :: nothrow )"))
|
|
type = type->link()->next();
|
|
|
|
// is it a user defined type?
|
|
if (!type->isStandardType()) {
|
|
const Variable* variable = _tokenizer->getSymbolDatabase()->getVariableFromVarId(start->varId());
|
|
if (!variable || !isRecordTypeWithoutSideEffects(*variable))
|
|
allocate = false;
|
|
}
|
|
}
|
|
|
|
if (allocate)
|
|
variables.allocateMemory(varid1);
|
|
else
|
|
variables.write(varid1);
|
|
} else if (varid1 && Token::Match(tok, "%varid% .", varid1)) {
|
|
variables.use(varid1);
|
|
} else {
|
|
variables.write(varid1);
|
|
}
|
|
|
|
Variables::VariableUsage *var2 = variables.find(tok->varId());
|
|
if (var2) {
|
|
if (var2->_type == Variables::reference) {
|
|
variables.writeAliases(tok->varId());
|
|
variables.read(tok->varId());
|
|
} else if (tok->varId() != varid1 && Token::Match(tok, "%var% ."))
|
|
variables.read(tok->varId());
|
|
else if (tok->varId() != varid1 &&
|
|
var2->_type == Variables::standard &&
|
|
tok->strAt(-1) != "&")
|
|
variables.use(tok->varId());
|
|
}
|
|
}
|
|
|
|
const Token *equal = skipBrackets(tok->next());
|
|
|
|
// checked for chained assignments
|
|
if (tok != start && equal && equal->str() == "=") {
|
|
Variables::VariableUsage *var = variables.find(tok->varId());
|
|
|
|
if (var && var->_type != Variables::reference)
|
|
var->_read = true;
|
|
|
|
tok = tok->previous();
|
|
}
|
|
}
|
|
|
|
// assignment
|
|
else if (Token::Match(tok, "%var% [") && Token::simpleMatch(skipBrackets(tok->next()), "=")) {
|
|
unsigned int varid = tok->varId();
|
|
const Variables::VariableUsage *var = variables.find(varid);
|
|
|
|
if (var) {
|
|
// Consider allocating memory separately because allocating/freeing alone does not constitute using the variable
|
|
if (var->_type == Variables::pointer &&
|
|
Token::Match(skipBrackets(tok->next()), "= new|malloc|calloc|g_malloc|kmalloc|vmalloc")) {
|
|
variables.allocateMemory(varid);
|
|
} else if (var->_type == Variables::pointer || var->_type == Variables::reference) {
|
|
variables.read(varid);
|
|
variables.writeAliases(varid);
|
|
} else
|
|
variables.writeAll(varid);
|
|
}
|
|
}
|
|
|
|
else if (Token::Match(tok, ">>|& %var%"))
|
|
variables.use(tok->next()->varId()); // use = read + write
|
|
else if (Token::Match(tok, "%var% >>|&") && Token::Match(tok->previous(), "[{};:]"))
|
|
variables.read(tok->varId());
|
|
|
|
// function parameter
|
|
else if (Token::Match(tok, "[(,] %var% ["))
|
|
variables.use(tok->next()->varId()); // use = read + write
|
|
else if (Token::Match(tok, "[(,] %var% [,)]") && tok->previous()->str() != "*") {
|
|
variables.use(tok->next()->varId()); // use = read + write
|
|
} else if (Token::Match(tok, "[(,] (") &&
|
|
Token::Match(tok->next()->link(), ") %var% [,)]"))
|
|
variables.use(tok->next()->link()->next()->varId()); // use = read + write
|
|
|
|
// function
|
|
else if (Token::Match(tok, "%var% (")) {
|
|
variables.read(tok->varId());
|
|
if (Token::Match(tok->tokAt(2), "%var% ="))
|
|
variables.read(tok->tokAt(2)->varId());
|
|
}
|
|
|
|
else if (Token::Match(tok, "[{,] %var% [,}]"))
|
|
variables.read(tok->next()->varId());
|
|
|
|
else if (Token::Match(tok, "%var% ."))
|
|
variables.use(tok->varId()); // use = read + write
|
|
|
|
else if ((Token::Match(tok, "[(=&!]") || tok->isExtendedOp()) &&
|
|
(Token::Match(tok->next(), "%var%") && !Token::Match(tok->next(), "true|false|new")) && tok->strAt(2) != "=")
|
|
variables.readAll(tok->next()->varId());
|
|
|
|
else if (Token::Match(tok, "%var%") && (tok->next()->str() == ")" || tok->next()->isExtendedOp()))
|
|
variables.readAll(tok->varId());
|
|
|
|
else if (Token::Match(tok, "%var% ;") && Token::Match(tok->previous(), "[;{}:]"))
|
|
variables.readAll(tok->varId());
|
|
|
|
else if (Token::Match(tok, "++|-- %var%")) {
|
|
if (!Token::Match(tok->previous(), "[;{}:]"))
|
|
variables.use(tok->next()->varId());
|
|
else
|
|
variables.modified(tok->next()->varId());
|
|
}
|
|
|
|
else if (Token::Match(tok, "%var% ++|--")) {
|
|
if (!Token::Match(tok->previous(), "[;{}:]"))
|
|
variables.use(tok->varId());
|
|
else
|
|
variables.modified(tok->varId());
|
|
}
|
|
|
|
else if (tok->isAssignmentOp()) {
|
|
for (const Token *tok2 = tok->next(); tok2 && tok2->str() != ";"; tok2 = tok2->next()) {
|
|
if (tok2->varId()) {
|
|
variables.read(tok2->varId());
|
|
if (tok2->next()->isAssignmentOp())
|
|
variables.write(tok2->varId());
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckUnusedVar::checkFunctionVariableUsage()
|
|
{
|
|
if (!_settings->isEnabled("style"))
|
|
return;
|
|
|
|
// Parse all executing scopes..
|
|
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
|
|
|
|
for (std::list<Scope>::const_iterator scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {
|
|
// only check functions
|
|
if (scope->type != Scope::eFunction)
|
|
continue;
|
|
|
|
// varId, usage {read, write, modified}
|
|
Variables variables;
|
|
|
|
checkFunctionVariableUsage_iterateScopes(&*scope, variables);
|
|
|
|
|
|
// Check usage of all variables in the current scope..
|
|
for (Variables::VariableMap::const_iterator it = variables.varUsage().begin(); it != variables.varUsage().end(); ++it) {
|
|
const Variables::VariableUsage &usage = it->second;
|
|
const std::string &varname = usage._name->str();
|
|
|
|
// variable has been marked as unused so ignore it
|
|
if (usage._name->isUnused())
|
|
continue;
|
|
|
|
// skip things that are only partially implemented to prevent false positives
|
|
if (usage._type == Variables::pointerPointer ||
|
|
usage._type == Variables::pointerArray ||
|
|
usage._type == Variables::referenceArray)
|
|
continue;
|
|
|
|
// variable has had memory allocated for it, but hasn't done
|
|
// anything with that memory other than, perhaps, freeing it
|
|
if (usage.unused() && !usage._modified && usage._allocateMemory)
|
|
allocatedButUnusedVariableError(usage._name, varname);
|
|
|
|
// variable has not been written, read, or modified
|
|
else if (usage.unused() && !usage._modified)
|
|
unusedVariableError(usage._name, varname);
|
|
|
|
// variable has not been written but has been modified
|
|
else if (usage._modified && !usage._write && !usage._allocateMemory)
|
|
unassignedVariableError(usage._name, varname);
|
|
|
|
// variable has been written but not read
|
|
else if (!usage._read && !usage._modified)
|
|
unreadVariableError(usage._name, varname);
|
|
|
|
// variable has been read but not written
|
|
else if (!usage._write && !usage._allocateMemory)
|
|
unassignedVariableError(usage._name, varname);
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckUnusedVar::unusedVariableError(const Token *tok, const std::string &varname)
|
|
{
|
|
reportError(tok, Severity::style, "unusedVariable", "Unused variable: " + varname);
|
|
}
|
|
|
|
void CheckUnusedVar::allocatedButUnusedVariableError(const Token *tok, const std::string &varname)
|
|
{
|
|
reportError(tok, Severity::style, "unusedAllocatedMemory", "Variable '" + varname + "' is allocated memory that is never used");
|
|
}
|
|
|
|
void CheckUnusedVar::unreadVariableError(const Token *tok, const std::string &varname)
|
|
{
|
|
reportError(tok, Severity::style, "unreadVariable", "Variable '" + varname + "' is assigned a value that is never used");
|
|
}
|
|
|
|
void CheckUnusedVar::unassignedVariableError(const Token *tok, const std::string &varname)
|
|
{
|
|
reportError(tok, Severity::style, "unassignedVariable", "Variable '" + varname + "' is not assigned a value");
|
|
}
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Check that all struct members are used
|
|
//---------------------------------------------------------------------------
|
|
void CheckUnusedVar::checkStructMemberUsage()
|
|
{
|
|
if (!_settings->isEnabled("style"))
|
|
return;
|
|
|
|
std::string structname;
|
|
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
|
|
if (tok->fileIndex() != 0)
|
|
continue;
|
|
|
|
if (Token::Match(tok, "struct|union %type% {")) {
|
|
structname.clear();
|
|
if (Token::simpleMatch(tok->previous(), "extern"))
|
|
continue;
|
|
if ((!tok->previous() || Token::simpleMatch(tok->previous(), ";")) && Token::Match(tok->linkAt(2), ("} ; " + tok->strAt(1) + " %var% ;").c_str()))
|
|
continue;
|
|
|
|
structname = tok->strAt(1);
|
|
|
|
// Bail out if struct/union contain any functions
|
|
for (const Token *tok2 = tok->tokAt(2); tok2; tok2 = tok2->next()) {
|
|
if (tok2->str() == "(") {
|
|
structname.clear();
|
|
break;
|
|
}
|
|
|
|
if (tok2->str() == "}")
|
|
break;
|
|
}
|
|
|
|
// bail out if struct is inherited
|
|
if (!structname.empty() && Token::findmatch(tok, (",|private|protected|public " + structname).c_str()))
|
|
structname.clear();
|
|
|
|
// Bail out if some data is casted to struct..
|
|
const std::string s("( struct| " + tok->next()->str() + " * ) & %var% [");
|
|
if (Token::findmatch(tok, s.c_str()))
|
|
structname.clear();
|
|
|
|
// Try to prevent false positives when struct members are not used directly.
|
|
if (Token::findmatch(tok, (structname + " *").c_str()))
|
|
structname.clear();
|
|
else if (Token::findmatch(tok, (structname + " %type% *").c_str()))
|
|
structname = "";
|
|
}
|
|
|
|
if (tok->str() == "}")
|
|
structname.clear();
|
|
|
|
if (!structname.empty() && Token::Match(tok, "[{;]")) {
|
|
// Declaring struct variable..
|
|
std::string varname;
|
|
|
|
// declaring a POD variable?
|
|
if (!tok->next()->isStandardType())
|
|
continue;
|
|
|
|
if (Token::Match(tok->next(), "%type% %var% [;[]"))
|
|
varname = tok->strAt(2);
|
|
else if (Token::Match(tok->next(), "%type% %type% %var% [;[]"))
|
|
varname = tok->strAt(3);
|
|
else if (Token::Match(tok->next(), "%type% * %var% [;[]"))
|
|
varname = tok->strAt(3);
|
|
else if (Token::Match(tok->next(), "%type% %type% * %var% [;[]"))
|
|
varname = tok->strAt(4);
|
|
else
|
|
continue;
|
|
|
|
// Check if the struct variable is used anywhere in the file
|
|
const std::string usagePattern(". " + varname);
|
|
bool used = false;
|
|
for (const Token *tok2 = _tokenizer->tokens(); tok2; tok2 = tok2->next()) {
|
|
if (Token::simpleMatch(tok2, usagePattern.c_str())) {
|
|
used = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (! used) {
|
|
unusedStructMemberError(tok->next(), structname, varname);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckUnusedVar::unusedStructMemberError(const Token *tok, const std::string &structname, const std::string &varname)
|
|
{
|
|
reportError(tok, Severity::style, "unusedStructMember", "struct or union member '" + structname + "::" + varname + "' is never used");
|
|
}
|