464 lines
18 KiB
C++
464 lines
18 KiB
C++
/*
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* Cppcheck - A tool for static C/C++ code analysis
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* Copyright (C) 2007-2022 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 "checkunusedfunctions.h"
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#include "astutils.h"
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#include "errorlogger.h"
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#include "errortypes.h"
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#include "library.h"
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#include "settings.h"
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#include "symboldatabase.h"
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#include "token.h"
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#include "tokenize.h"
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#include "tokenlist.h"
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#include <algorithm>
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#include <cctype>
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#include <cstdlib>
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#include <cstring>
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#include <istream>
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#include <memory>
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#include <utility>
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#include <vector>
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#include <tinyxml2.h>
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namespace CTU {
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class FileInfo;
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}
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//---------------------------------------------------------------------------
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// Register this check class
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CheckUnusedFunctions CheckUnusedFunctions::instance;
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static const struct CWE CWE561(561U); // Dead Code
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//---------------------------------------------------------------------------
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// FUNCTION USAGE - Check for unused functions etc
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//---------------------------------------------------------------------------
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void CheckUnusedFunctions::parseTokens(const Tokenizer &tokenizer, const char FileName[], const Settings *settings)
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{
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const bool doMarkup = settings->library.markupFile(FileName);
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const SymbolDatabase* symbolDatabase = tokenizer.getSymbolDatabase();
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// Function declarations..
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for (const Scope* scope : symbolDatabase->functionScopes) {
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const Function* func = scope->function;
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if (!func || !func->token || scope->bodyStart->fileIndex() != 0)
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continue;
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// Don't warn about functions that are marked by __attribute__((constructor)) or __attribute__((destructor))
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if (func->isAttributeConstructor() || func->isAttributeDestructor() || func->type != Function::eFunction || func->isOperator())
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continue;
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// Don't care about templates
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if (tokenizer.isCPP() && func->templateDef != nullptr)
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continue;
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mFunctionDecl.emplace_back(func);
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FunctionUsage &usage = mFunctions[func->name()];
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if (!usage.lineNumber)
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usage.lineNumber = func->token->linenr();
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// No filename set yet..
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if (usage.filename.empty()) {
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usage.filename = tokenizer.list.getSourceFilePath();
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}
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// Multiple files => filename = "+"
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else if (usage.filename != tokenizer.list.getSourceFilePath()) {
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//func.filename = "+";
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usage.usedOtherFile |= usage.usedSameFile;
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}
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}
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// Function usage..
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const Token *lambdaEndToken = nullptr;
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for (const Token *tok = tokenizer.tokens(); tok; tok = tok->next()) {
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if (tok == lambdaEndToken)
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lambdaEndToken = nullptr;
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else if (!lambdaEndToken && tok->str() == "[")
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lambdaEndToken = findLambdaEndToken(tok);
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// parsing of library code to find called functions
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if (settings->library.isexecutableblock(FileName, tok->str())) {
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const Token * markupVarToken = tok->tokAt(settings->library.blockstartoffset(FileName));
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// not found
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if (!markupVarToken)
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continue;
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int scope = 0;
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bool start = true;
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// find all function calls in library code (starts with '(', not if or while etc)
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while ((scope || start) && markupVarToken) {
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if (markupVarToken->str() == settings->library.blockstart(FileName)) {
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scope++;
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if (start) {
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start = false;
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}
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} else if (markupVarToken->str() == settings->library.blockend(FileName))
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scope--;
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else if (!settings->library.iskeyword(FileName, markupVarToken->str())) {
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mFunctionCalls.insert(markupVarToken->str());
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if (mFunctions.find(markupVarToken->str()) != mFunctions.end())
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mFunctions[markupVarToken->str()].usedOtherFile = true;
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else if (markupVarToken->next()->str() == "(") {
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FunctionUsage &func = mFunctions[markupVarToken->str()];
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func.filename = tokenizer.list.getSourceFilePath();
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if (func.filename.empty() || func.filename == "+")
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func.usedOtherFile = true;
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else
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func.usedSameFile = true;
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}
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}
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markupVarToken = markupVarToken->next();
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}
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}
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if (!doMarkup // only check source files
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&& settings->library.isexporter(tok->str()) && tok->next() != nullptr) {
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const Token * propToken = tok->next();
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while (propToken && propToken->str() != ")") {
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if (settings->library.isexportedprefix(tok->str(), propToken->str())) {
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const Token* nextPropToken = propToken->next();
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const std::string& value = nextPropToken->str();
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if (mFunctions.find(value) != mFunctions.end()) {
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mFunctions[value].usedOtherFile = true;
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}
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mFunctionCalls.insert(value);
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}
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if (settings->library.isexportedsuffix(tok->str(), propToken->str())) {
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const Token* prevPropToken = propToken->previous();
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const std::string& value = prevPropToken->str();
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if (value != ")" && mFunctions.find(value) != mFunctions.end()) {
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mFunctions[value].usedOtherFile = true;
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}
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mFunctionCalls.insert(value);
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}
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propToken = propToken->next();
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}
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}
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if (doMarkup && settings->library.isimporter(FileName, tok->str()) && tok->next()) {
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const Token * propToken = tok->next();
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if (propToken->next()) {
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propToken = propToken->next();
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while (propToken && propToken->str() != ")") {
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const std::string& value = propToken->str();
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if (!value.empty()) {
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mFunctions[value].usedOtherFile = true;
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mFunctionCalls.insert(value);
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break;
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}
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propToken = propToken->next();
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}
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}
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}
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if (settings->library.isreflection(tok->str())) {
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const int argIndex = settings->library.reflectionArgument(tok->str());
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if (argIndex >= 0) {
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const Token * funcToken = tok->next();
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int index = 0;
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std::string value;
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while (funcToken) {
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if (funcToken->str()==",") {
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if (++index == argIndex)
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break;
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value.clear();
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} else
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value += funcToken->str();
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funcToken = funcToken->next();
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}
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if (index == argIndex) {
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value = value.substr(1, value.length() - 2);
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mFunctions[value].usedOtherFile = true;
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mFunctionCalls.insert(value);
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}
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}
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}
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const Token *funcname = nullptr;
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if ((lambdaEndToken || tok->scope()->isExecutable()) && Token::Match(tok, "%name% (")) {
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funcname = tok;
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} else if ((lambdaEndToken || tok->scope()->isExecutable()) && Token::Match(tok, "%name% <") && Token::simpleMatch(tok->linkAt(1), "> (")) {
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funcname = tok;
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} else if (Token::Match(tok, "< %name%") && tok->link()) {
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funcname = tok->next();
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while (Token::Match(funcname, "%name% :: %name%"))
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funcname = funcname->tokAt(2);
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} else if (Token::Match(tok, "[;{}.,()[=+-/|!?:]")) {
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funcname = tok->next();
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if (funcname && funcname->str() == "&")
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funcname = funcname->next();
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if (funcname && funcname->str() == "::")
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funcname = funcname->next();
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while (Token::Match(funcname, "%name% :: %name%"))
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funcname = funcname->tokAt(2);
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if (!Token::Match(funcname, "%name% [(),;]:}>]"))
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continue;
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}
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if (!funcname)
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continue;
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// funcname ( => Assert that the end parentheses isn't followed by {
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if (Token::Match(funcname, "%name% (|<")) {
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const Token *ftok = funcname->next();
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if (ftok->str() == "<")
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ftok = ftok->link();
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if (Token::Match(ftok->linkAt(1), ") const|throw|{"))
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funcname = nullptr;
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}
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if (funcname) {
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FunctionUsage &func = mFunctions[funcname->str()];
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const std::string& called_from_file = tokenizer.list.getSourceFilePath();
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if (func.filename.empty() || func.filename == "+" || func.filename != called_from_file)
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func.usedOtherFile = true;
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else
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func.usedSameFile = true;
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mFunctionCalls.insert(funcname->str());
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}
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}
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}
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static bool isOperatorFunction(const std::string & funcName)
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{
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/* Operator functions are invalid function names for C, so no need to check
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* this in here. As result the returned error function might be incorrect.
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*
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* List of valid operators can be found at:
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* http://en.cppreference.com/w/cpp/language/operators
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*
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* Conversion functions must be a member function (at least for gcc), so no
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* need to cover them for unused functions.
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*
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* To speed up the comparison, not the whole list of operators is used.
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* Instead only the character after the operator prefix is checked to be a
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* none alpa numeric value, but the '_', to cover function names like
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* "operator_unused". In addition the following valid operators are checked:
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* - new
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* - new[]
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* - delete
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* - delete[]
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*/
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const std::string operatorPrefix = "operator";
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if (funcName.compare(0, operatorPrefix.length(), operatorPrefix) != 0) {
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return false;
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}
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// Taking care of funcName == "operator", which is no valid operator
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if (funcName.length() == operatorPrefix.length()) {
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return false;
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}
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const char firstOperatorChar = funcName[operatorPrefix.length()];
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if (firstOperatorChar == '_') {
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return false;
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}
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if (!std::isalnum(firstOperatorChar)) {
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return true;
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}
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const std::vector<std::string> additionalOperators = {
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"new", "new[]", "delete", "delete[]"
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};
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return std::find(additionalOperators.begin(), additionalOperators.end(), funcName.substr(operatorPrefix.length())) != additionalOperators.end();
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}
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bool CheckUnusedFunctions::check(ErrorLogger * const errorLogger, const Settings& settings) const
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{
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bool errors = false;
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for (std::map<std::string, FunctionUsage>::const_iterator it = mFunctions.begin(); it != mFunctions.end(); ++it) {
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const FunctionUsage &func = it->second;
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if (func.usedOtherFile || func.filename.empty())
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continue;
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if (it->first == "main" ||
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(settings.isWindowsPlatform() && (it->first == "WinMain" || it->first == "_tmain")) ||
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it->first == "if")
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continue;
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if (!func.usedSameFile) {
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if (isOperatorFunction(it->first))
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continue;
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std::string filename;
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if (func.filename != "+")
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filename = func.filename;
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unusedFunctionError(errorLogger, filename, func.lineNumber, it->first);
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errors = true;
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} else if (!func.usedOtherFile) {
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/** @todo add error message "function is only used in <file> it can be static" */
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/*
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std::ostringstream errmsg;
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errmsg << "The function '" << it->first << "' is only used in the file it was declared in so it should have local linkage.";
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mErrorLogger->reportErr( errmsg.str() );
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errors = true;
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*/
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}
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}
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return errors;
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}
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void CheckUnusedFunctions::unusedFunctionError(ErrorLogger * const errorLogger,
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const std::string &filename, unsigned int lineNumber,
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const std::string &funcname)
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{
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std::list<ErrorMessage::FileLocation> locationList;
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if (!filename.empty()) {
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ErrorMessage::FileLocation fileLoc;
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fileLoc.setfile(filename);
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fileLoc.line = lineNumber;
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locationList.push_back(fileLoc);
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}
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const ErrorMessage errmsg(locationList, emptyString, Severity::style, "$symbol:" + funcname + "\nThe function '$symbol' is never used.", "unusedFunction", CWE561, Certainty::normal);
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if (errorLogger)
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errorLogger->reportErr(errmsg);
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else
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reportError(errmsg);
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}
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Check::FileInfo *CheckUnusedFunctions::getFileInfo(const Tokenizer *tokenizer, const Settings *settings) const
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{
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if (!settings->checks.isEnabled(Checks::unusedFunction))
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return nullptr;
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if (settings->jobs == 1 && settings->buildDir.empty())
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instance.parseTokens(*tokenizer, tokenizer->list.getFiles().front().c_str(), settings);
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return nullptr;
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}
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bool CheckUnusedFunctions::analyseWholeProgram(const CTU::FileInfo *ctu, const std::list<Check::FileInfo*> &fileInfo, const Settings& settings, ErrorLogger &errorLogger)
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{
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(void)ctu;
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(void)fileInfo;
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return check(&errorLogger, settings);
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}
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CheckUnusedFunctions::FunctionDecl::FunctionDecl(const Function *f)
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: functionName(f->name()), lineNumber(f->token->linenr())
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{}
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std::string CheckUnusedFunctions::analyzerInfo() const
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{
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std::ostringstream ret;
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for (const FunctionDecl &functionDecl : mFunctionDecl) {
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ret << " <functiondecl"
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<< " functionName=\"" << ErrorLogger::toxml(functionDecl.functionName) << '\"'
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<< " lineNumber=\"" << functionDecl.lineNumber << "\"/>\n";
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}
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for (const std::string &fc : mFunctionCalls) {
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ret << " <functioncall functionName=\"" << ErrorLogger::toxml(fc) << "\"/>\n";
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}
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return ret.str();
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}
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namespace {
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struct Location {
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Location() : lineNumber(0) {}
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Location(const std::string &f, const int l) : fileName(f), lineNumber(l) {}
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std::string fileName;
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int lineNumber;
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};
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}
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void CheckUnusedFunctions::analyseWholeProgram(ErrorLogger * const errorLogger, const std::string &buildDir)
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{
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std::map<std::string, Location> decls;
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std::set<std::string> calls;
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const std::string filesTxt(buildDir + "/files.txt");
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std::ifstream fin(filesTxt.c_str());
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std::string filesTxtLine;
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while (std::getline(fin, filesTxtLine)) {
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const std::string::size_type firstColon = filesTxtLine.find(':');
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if (firstColon == std::string::npos)
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continue;
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const std::string::size_type secondColon = filesTxtLine.find(':', firstColon+1);
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if (secondColon == std::string::npos)
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continue;
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const std::string xmlfile = buildDir + '/' + filesTxtLine.substr(0,firstColon);
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const std::string sourcefile = filesTxtLine.substr(secondColon+1);
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tinyxml2::XMLDocument doc;
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const tinyxml2::XMLError error = doc.LoadFile(xmlfile.c_str());
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if (error != tinyxml2::XML_SUCCESS)
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continue;
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const tinyxml2::XMLElement * const rootNode = doc.FirstChildElement();
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if (rootNode == nullptr)
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continue;
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for (const tinyxml2::XMLElement *e = rootNode->FirstChildElement(); e; e = e->NextSiblingElement()) {
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if (std::strcmp(e->Name(), "FileInfo") != 0)
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continue;
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const char *checkattr = e->Attribute("check");
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if (checkattr == nullptr || std::strcmp(checkattr,"CheckUnusedFunctions") != 0)
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continue;
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for (const tinyxml2::XMLElement *e2 = e->FirstChildElement(); e2; e2 = e2->NextSiblingElement()) {
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const char* functionName = e2->Attribute("functionName");
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if (functionName == nullptr)
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continue;
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if (std::strcmp(e2->Name(),"functioncall") == 0) {
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calls.insert(functionName);
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continue;
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} else if (std::strcmp(e2->Name(),"functiondecl") == 0) {
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const char* lineNumber = e2->Attribute("lineNumber");
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if (lineNumber)
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decls[functionName] = Location(sourcefile, std::atoi(lineNumber));
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}
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}
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}
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}
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for (std::map<std::string, Location>::const_iterator decl = decls.begin(); decl != decls.end(); ++decl) {
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const std::string &functionName = decl->first;
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// TODO: move to configuration files
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// TODO: WinMain, wmain and _tmain only apply to Windows code
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// TODO: also skip other known entry functions i.e. annotated with "constructor" and "destructor" attributes
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if (functionName == "main" || functionName == "WinMain" || functionName == "wmain" || functionName == "_tmain" ||
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functionName == "if")
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continue;
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if (calls.find(functionName) == calls.end() && !isOperatorFunction(functionName)) {
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const Location &loc = decl->second;
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unusedFunctionError(errorLogger, loc.fileName, loc.lineNumber, functionName);
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}
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}
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}
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