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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2025 Cppcheck team.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
//---------------------------------------------------------------------------
#include "checkunusedfunctions.h"
#include "astutils.h"
#include "errorlogger.h"
#include "errortypes.h"
#include "library.h"
#include "settings.h"
#include "symboldatabase.h"
#include "token.h"
#include "tokenize.h"
#include "tokenlist.h"
#include "utils.h"
#include <algorithm>
#include <cctype>
#include <cstring>
#include <fstream>
#include <map>
#include <sstream>
#include <tuple>
#include <utility>
#include <vector>
#include "xml.h"
//---------------------------------------------------------------------------
static const CWE CWE561(561U); // Dead Code
static std::string stripTemplateParameters(const std::string& funcName) {
std::string name = funcName;
const auto pos = name.find('<');
if (pos > 0 && pos != std::string::npos)
name.erase(pos - 1);
return name;
}
//---------------------------------------------------------------------------
// FUNCTION USAGE - Check for unused functions etc
//---------------------------------------------------------------------------
static bool isRecursiveCall(const Token* ftok)
{
return ftok->function() && ftok->function() == Scope::nestedInFunction(ftok->scope());
}
void CheckUnusedFunctions::parseTokens(const Tokenizer &tokenizer, const Settings &settings)
{
const char * const FileName = tokenizer.list.getFiles().front().c_str();
const bool doMarkup = settings.library.markupFile(FileName);
// Function declarations..
if (!doMarkup) {
const SymbolDatabase* symbolDatabase = tokenizer.getSymbolDatabase();
for (const Scope* scope : symbolDatabase->functionScopes) {
const Function* func = scope->function;
if (!func || !func->token)
continue;
// Don't warn about functions that are marked by __attribute__((constructor)) or __attribute__((destructor))
if (func->isAttributeConstructor() || func->isAttributeDestructor() || func->type != Function::eFunction || func->isOperator())
continue;
if (func->isAttributeUnused() || func->isAttributeMaybeUnused())
continue;
if (func->isExtern())
continue;
bool foundAllBaseClasses{};
if (const Function* ofunc = func->getOverriddenFunction(&foundAllBaseClasses)) {
if (!foundAllBaseClasses || ofunc->isPure())
continue;
}
else if (func->isImplicitlyVirtual()) {
continue;
}
mFunctionDecl.emplace_back(func);
FunctionUsage &usage = mFunctions[stripTemplateParameters(func->name())];
if (func->retDef && (func->retDef->isAttributeUnused() || func->retDef->isAttributeMaybeUnused())) {
usage.usedOtherFile = true;
}
if (!usage.lineNumber)
usage.lineNumber = func->token->linenr();
usage.isC = func->token->isC();
usage.isStatic = func->isStatic();
// TODO: why always overwrite this but not the filename and line?
usage.fileIndex = func->token->fileIndex();
const std::string& fileName = tokenizer.list.file(func->token);
// No filename set yet..
if (usage.filename.empty()) {
usage.filename = fileName;
}
// Multiple files => filename = "+"
else if (usage.filename != fileName) {
//func.filename = "+";
usage.usedOtherFile |= usage.usedSameFile;
}
}
}
// Function usage..
const Token *lambdaEndToken = nullptr;
for (const Token *tok = tokenizer.tokens(); tok; tok = tok->next()) {
if (tok == lambdaEndToken)
lambdaEndToken = nullptr;
else if (!lambdaEndToken && tok->str() == "[")
lambdaEndToken = findLambdaEndToken(tok);
// parsing of library code to find called functions
if (settings.library.isexecutableblock(FileName, tok->str())) {
const Token * markupVarToken = tok->tokAt(settings.library.blockstartoffset(FileName));
// not found
if (!markupVarToken)
continue;
int scope = 0;
bool start = true;
// find all function calls in library code (starts with '(', not if or while etc)
while ((scope || start) && markupVarToken) {
if (markupVarToken->str() == settings.library.blockstart(FileName)) {
scope++;
start = false;
} else if (markupVarToken->str() == settings.library.blockend(FileName))
scope--;
else if (!settings.library.iskeyword(FileName, markupVarToken->str())) {
mFunctionCalls.insert(markupVarToken->str());
if (mFunctions.find(markupVarToken->str()) != mFunctions.end())
mFunctions[markupVarToken->str()].usedOtherFile = true;
else if (markupVarToken->strAt(1) == "(") {
FunctionUsage &func = mFunctions[markupVarToken->str()];
func.filename = tokenizer.list.getFiles()[markupVarToken->fileIndex()];
if (func.filename.empty() || func.filename == "+")
func.usedOtherFile = true;
else
func.usedSameFile = true;
}
}
markupVarToken = markupVarToken->next();
}
}
if (!doMarkup // only check source files
&& settings.library.isexporter(tok->str()) && tok->next() != nullptr) {
const Token * propToken = tok->next();
while (propToken && propToken->str() != ")") {
if (settings.library.isexportedprefix(tok->str(), propToken->str())) {
const Token* nextPropToken = propToken->next();
const std::string& value = nextPropToken->str();
if (mFunctions.find(value) != mFunctions.end()) {
mFunctions[value].usedOtherFile = true;
}
mFunctionCalls.insert(value);
}
if (settings.library.isexportedsuffix(tok->str(), propToken->str())) {
const Token* prevPropToken = propToken->previous();
const std::string& value = prevPropToken->str();
if (value != ")" && mFunctions.find(value) != mFunctions.end()) {
mFunctions[value].usedOtherFile = true;
}
mFunctionCalls.insert(value);
}
propToken = propToken->next();
}
}
if (doMarkup && settings.library.isimporter(FileName, tok->str()) && tok->next()) {
const Token * propToken = tok->next();
if (propToken->next()) {
propToken = propToken->next();
while (propToken && propToken->str() != ")") {
const std::string& value = propToken->str();
if (!value.empty()) {
mFunctions[value].usedOtherFile = true;
mFunctionCalls.insert(value);
break;
}
propToken = propToken->next();
}
}
}
if (settings.library.isreflection(tok->str())) {
const int argIndex = settings.library.reflectionArgument(tok->str());
if (argIndex >= 0) {
const Token * funcToken = tok->next();
int index = 0;
std::string value;
while (funcToken) {
if (funcToken->str()==",") {
if (++index == argIndex)
break;
value.clear();
} else
value += funcToken->str();
funcToken = funcToken->next();
}
if (index == argIndex) {
value = value.substr(1, value.length() - 2);
mFunctions[value].usedOtherFile = true;
mFunctionCalls.insert(std::move(value));
}
}
}
if (tok->hasAttributeCleanup()) {
const std::string& funcname = tok->getAttributeCleanup();
mFunctions[funcname].usedOtherFile = true;
mFunctionCalls.insert(funcname);
continue;
}
const Token *funcname = nullptr;
if (doMarkup)
funcname = Token::Match(tok, "%name% (") ? tok : nullptr;
else if ((lambdaEndToken || tok->scope()->isExecutable()) && Token::Match(tok, "%name% (")) {
funcname = tok;
} else if ((lambdaEndToken || tok->scope()->isExecutable()) && Token::Match(tok, "%name% <") && Token::simpleMatch(tok->linkAt(1), "> (")) {
funcname = tok;
} else if (Token::Match(tok, "< %name%") && tok->link()) {
funcname = tok->next();
while (Token::Match(funcname, "%name% :: %name%"))
funcname = funcname->tokAt(2);
} else if (tok->scope()->type != Scope::ScopeType::eEnum && (Token::Match(tok, "[;{}.,()[=+-/|!?:]") || Token::Match(tok, "return|throw"))) {
funcname = tok->next();
if (funcname && funcname->str() == "&")
funcname = funcname->next();
if (funcname && funcname->str() == "::")
funcname = funcname->next();
while (Token::Match(funcname, "%name% :: %name%"))
funcname = funcname->tokAt(2);
if (!Token::Match(funcname, "%name% [(),;]:}<>]"))
continue;
}
if (!funcname || funcname->isKeyword() || funcname->isStandardType() || funcname->varId() || funcname->enumerator() || funcname->type())
continue;
// funcname ( => Assert that the end parentheses isn't followed by {
if (Token::Match(funcname, "%name% (|<") && funcname->linkAt(1)) {
const Token *ftok = funcname->next();
if (ftok->str() == "<")
ftok = ftok->link();
if (Token::Match(ftok->linkAt(1), ") const|throw|{"))
funcname = nullptr;
}
if (funcname) {
if (isRecursiveCall(funcname))
continue;
const auto baseName = stripTemplateParameters(funcname->str());
FunctionUsage &func = mFunctions[baseName];
const std::string& called_from_file = tokenizer.list.getFiles()[funcname->fileIndex()];
if (func.filename.empty() || func.filename == "+" || func.filename != called_from_file)
func.usedOtherFile = true;
else
func.usedSameFile = true;
mFunctionCalls.insert(baseName);
}
}
}
static bool isOperatorFunction(const std::string & funcName)
{
/* Operator functions are invalid function names for C, so no need to check
* this in here. As result the returned error function might be incorrect.
*
* List of valid operators can be found at:
* http://en.cppreference.com/w/cpp/language/operators
*
* Conversion functions must be a member function (at least for gcc), so no
* need to cover them for unused functions.
*
* To speed up the comparison, not the whole list of operators is used.
* Instead only the character after the operator prefix is checked to be a
* none alpa numeric value, but the '_', to cover function names like
* "operator_unused". In addition the following valid operators are checked:
* - new
* - new[]
* - delete
* - delete[]
*/
const std::string operatorPrefix = "operator";
if (funcName.compare(0, operatorPrefix.length(), operatorPrefix) != 0) {
return false;
}
// Taking care of funcName == "operator", which is no valid operator
if (funcName.length() == operatorPrefix.length()) {
return false;
}
const char firstOperatorChar = funcName[operatorPrefix.length()];
if (firstOperatorChar == '_') {
return false;
}
if (!std::isalnum(firstOperatorChar)) {
return true;
}
const std::vector<std::string> additionalOperators = {
"new", "new[]", "delete", "delete[]"
};
return std::find(additionalOperators.cbegin(), additionalOperators.cend(), funcName.substr(operatorPrefix.length())) != additionalOperators.cend();
}
static void staticFunctionError(ErrorLogger& errorLogger,
const std::string &filename,
unsigned int fileIndex,
unsigned int lineNumber,
const std::string &funcname)
{
std::list<ErrorMessage::FileLocation> locationList;
if (!filename.empty()) {
locationList.emplace_back(filename, lineNumber, 0);
locationList.back().fileIndex = fileIndex;
}
const ErrorMessage errmsg(std::move(locationList), "", Severity::style, "$symbol:" + funcname + "\nThe function '$symbol' should have static linkage since it is not used outside of its translation unit.", "staticFunction", Certainty::normal);
errorLogger.reportErr(errmsg);
}
#define logChecker(id) \
do { \
const ErrorMessage errmsg({}, nullptr, Severity::internal, "logChecker", (id), CWE(0U), Certainty::normal); \
errorLogger.reportErr(errmsg); \
} while (false)
bool CheckUnusedFunctions::check(const Settings& settings, ErrorLogger& errorLogger) const
{
logChecker("CheckUnusedFunctions::check"); // unusedFunction
using ErrorParams = std::tuple<std::string, unsigned int, unsigned int, std::string>;
std::vector<ErrorParams> errors; // ensure well-defined order
std::vector<ErrorParams> staticFunctionErrors;
for (auto it = mFunctions.cbegin(); it != mFunctions.cend(); ++it) {
const FunctionUsage &func = it->second;
if (func.usedOtherFile || func.filename.empty())
continue;
if (settings.library.isentrypoint(it->first))
continue;
if (!func.usedSameFile) {
if (isOperatorFunction(it->first))
continue;
std::string filename;
if (func.filename != "+")
filename = func.filename;
errors.emplace_back(filename, func.fileIndex, func.lineNumber, it->first);
} else if (func.isC && !func.isStatic && !func.usedOtherFile) {
std::string filename;
if (func.filename != "+")
filename = func.filename;
staticFunctionErrors.emplace_back(filename, func.fileIndex, func.lineNumber, it->first);
}
}
std::sort(errors.begin(), errors.end());
for (const auto& e : errors)
unusedFunctionError(errorLogger, std::get<0>(e), std::get<1>(e), std::get<2>(e), std::get<3>(e));
std::sort(staticFunctionErrors.begin(), staticFunctionErrors.end());
for (const auto& e : staticFunctionErrors)
staticFunctionError(errorLogger, std::get<0>(e), std::get<1>(e), std::get<2>(e), std::get<3>(e));
return !errors.empty();
}
void CheckUnusedFunctions::unusedFunctionError(ErrorLogger& errorLogger,
const std::string &filename, unsigned int fileIndex, unsigned int lineNumber,
const std::string &funcname)
{
std::list<ErrorMessage::FileLocation> locationList;
if (!filename.empty()) {
locationList.emplace_back(filename, lineNumber, 0);
locationList.back().fileIndex = fileIndex;
}
const ErrorMessage errmsg(std::move(locationList), "", Severity::style, "$symbol:" + funcname + "\nThe function '$symbol' is never used.", "unusedFunction", CWE561, Certainty::normal);
errorLogger.reportErr(errmsg);
}
CheckUnusedFunctions::FunctionDecl::FunctionDecl(const Function *f)
: functionName(f->name()), fileName(f->token->fileName()), lineNumber(f->token->linenr())
{}
std::string CheckUnusedFunctions::analyzerInfo() const
{
std::ostringstream ret;
for (const FunctionDecl &functionDecl : mFunctionDecl) {
ret << " <functiondecl"
<< " file=\"" << ErrorLogger::toxml(functionDecl.fileName) << '\"'
<< " functionName=\"" << ErrorLogger::toxml(functionDecl.functionName) << '\"'
<< " lineNumber=\"" << functionDecl.lineNumber << "\"/>\n";
}
for (const std::string &fc : mFunctionCalls) {
ret << " <functioncall functionName=\"" << ErrorLogger::toxml(fc) << "\"/>\n";
}
return ret.str();
}
namespace {
struct Location {
Location() : lineNumber(0) {}
Location(std::string f, const int l) : fileName(std::move(f)), lineNumber(l) {}
std::string fileName;
int lineNumber;
};
}
void CheckUnusedFunctions::analyseWholeProgram(const Settings &settings, ErrorLogger &errorLogger, const std::string &buildDir)
{
std::map<std::string, Location> decls;
std::set<std::string> calls;
const std::string filesTxt(buildDir + "/files.txt");
std::ifstream fin(filesTxt.c_str());
std::string filesTxtLine;
while (std::getline(fin, filesTxtLine)) {
const std::string::size_type firstColon = filesTxtLine.find(':');
if (firstColon == std::string::npos)
continue;
const std::string::size_type secondColon = filesTxtLine.find(':', firstColon+1);
if (secondColon == std::string::npos)
continue;
const std::string xmlfile = buildDir + '/' + filesTxtLine.substr(0,firstColon);
const std::string sourcefile = filesTxtLine.substr(secondColon+1);
tinyxml2::XMLDocument doc;
const tinyxml2::XMLError error = doc.LoadFile(xmlfile.c_str());
if (error != tinyxml2::XML_SUCCESS)
continue;
const tinyxml2::XMLElement * const rootNode = doc.FirstChildElement();
if (rootNode == nullptr)
continue;
for (const tinyxml2::XMLElement *e = rootNode->FirstChildElement(); e; e = e->NextSiblingElement()) {
if (std::strcmp(e->Name(), "FileInfo") != 0)
continue;
const char *checkattr = e->Attribute("check");
if (checkattr == nullptr || std::strcmp(checkattr,"CheckUnusedFunctions") != 0)
continue;
for (const tinyxml2::XMLElement *e2 = e->FirstChildElement(); e2; e2 = e2->NextSiblingElement()) {
const char* functionName = e2->Attribute("functionName");
if (functionName == nullptr)
continue;
const char* name = e2->Name();
if (std::strcmp(name,"functioncall") == 0) {
calls.insert(functionName);
continue;
}
if (std::strcmp(name,"functiondecl") == 0) {
const char* lineNumber = e2->Attribute("lineNumber");
if (lineNumber) {
const char* file = e2->Attribute("file");
// cppcheck-suppress templateInstantiation - TODO: fix this - see #11631
decls[functionName] = Location(file ? file : sourcefile, strToInt<int>(lineNumber));
}
}
}
}
}
for (auto decl = decls.cbegin(); decl != decls.cend(); ++decl) {
const std::string &functionName = stripTemplateParameters(decl->first);
if (settings.library.isentrypoint(functionName))
continue;
if (calls.find(functionName) == calls.end() && !isOperatorFunction(functionName)) {
const Location &loc = decl->second;
unusedFunctionError(errorLogger, loc.fileName, /*fileIndex*/ 0, loc.lineNumber, functionName);
}
}
}
void CheckUnusedFunctions::updateFunctionData(const CheckUnusedFunctions& check)
{
for (const auto& entry : check.mFunctions)
{
FunctionUsage &usage = mFunctions[entry.first];
if (!usage.lineNumber)
usage.lineNumber = entry.second.lineNumber;
// TODO: why always overwrite this but not the filename and line?
usage.fileIndex = entry.second.fileIndex;
if (usage.filename.empty())
usage.filename = entry.second.filename;
// cppcheck-suppress bitwiseOnBoolean - TODO: FP
usage.usedOtherFile |= entry.second.usedOtherFile;
// cppcheck-suppress bitwiseOnBoolean - TODO: FP
usage.usedSameFile |= entry.second.usedSameFile;
}
mFunctionDecl.insert(mFunctionDecl.cend(), check.mFunctionDecl.cbegin(), check.mFunctionDecl.cend());
mFunctionCalls.insert(check.mFunctionCalls.cbegin(), check.mFunctionCalls.cend());
}
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