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448 lines (390 loc) · 17.5 KB
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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2021 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 "library.h"
#include "settings.h"
#include "symboldatabase.h"
#include "token.h"
#include "tokenize.h"
#include "tokenlist.h"
#include <tinyxml2.h>
#include <algorithm>
#include <cstdlib>
#include <cstring>
#include <utility>
//---------------------------------------------------------------------------
// Register this check class
CheckUnusedFunctions CheckUnusedFunctions::instance;
static const struct CWE CWE561(561U); // Dead Code
//---------------------------------------------------------------------------
// FUNCTION USAGE - Check for unused functions etc
//---------------------------------------------------------------------------
void CheckUnusedFunctions::parseTokens(const Tokenizer &tokenizer, const char FileName[], const Settings *settings)
{
const bool doMarkup = settings->library.markupFile(FileName);
const SymbolDatabase* symbolDatabase = tokenizer.getSymbolDatabase();
// Function declarations..
for (const Scope* scope : symbolDatabase->functionScopes) {
const Function* func = scope->function;
if (!func || !func->token || scope->bodyStart->fileIndex() != 0)
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;
// Don't care about templates
if (tokenizer.isCPP() && func->templateDef != nullptr)
continue;
mFunctionDecl.emplace_back(func);
FunctionUsage &usage = mFunctions[func->name()];
if (!usage.lineNumber)
usage.lineNumber = func->token->linenr();
// No filename set yet..
if (usage.filename.empty()) {
usage.filename = tokenizer.list.getSourceFilePath();
}
// Multiple files => filename = "+"
else if (usage.filename != tokenizer.list.getSourceFilePath()) {
//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++;
if (start) {
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->next()->str() == "(") {
FunctionUsage &func = mFunctions[markupVarToken->str()];
func.filename = tokenizer.list.getSourceFilePath();
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(value);
}
}
}
const Token *funcname = nullptr;
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 (Token::Match(tok, "[;{}.,()[=+-/|!?:]")) {
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)
continue;
// funcname ( => Assert that the end parentheses isn't followed by {
if (Token::Match(funcname, "%name% (|<")) {
const Token *ftok = funcname->next();
if (ftok->str() == "<")
ftok = ftok->link();
if (Token::Match(ftok->linkAt(1), ") const|throw|{"))
funcname = nullptr;
}
if (funcname) {
FunctionUsage &func = mFunctions[funcname->str()];
const std::string& called_from_file = tokenizer.list.getSourceFilePath();
if (func.filename.empty() || func.filename == "+" || func.filename != called_from_file)
func.usedOtherFile = true;
else
func.usedSameFile = true;
mFunctionCalls.insert(funcname->str());
}
}
}
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.begin(), additionalOperators.end(), funcName.substr(operatorPrefix.length())) != additionalOperators.end();
}
bool CheckUnusedFunctions::check(ErrorLogger * const errorLogger, const Settings& settings)
{
bool errors = false;
for (std::map<std::string, FunctionUsage>::const_iterator it = mFunctions.begin(); it != mFunctions.end(); ++it) {
const FunctionUsage &func = it->second;
if (func.usedOtherFile || func.filename.empty())
continue;
if (it->first == "main" ||
(settings.isWindowsPlatform() && (it->first == "WinMain" || it->first == "_tmain")) ||
it->first == "if")
continue;
if (!func.usedSameFile) {
if (isOperatorFunction(it->first))
continue;
std::string filename;
if (func.filename != "+")
filename = func.filename;
unusedFunctionError(errorLogger, filename, func.lineNumber, it->first);
errors = true;
} else if (!func.usedOtherFile) {
/** @todo add error message "function is only used in <file> it can be static" */
/*
std::ostringstream errmsg;
errmsg << "The function '" << it->first << "' is only used in the file it was declared in so it should have local linkage.";
mErrorLogger->reportErr( errmsg.str() );
errors = true;
*/
}
}
return errors;
}
void CheckUnusedFunctions::unusedFunctionError(ErrorLogger * const errorLogger,
const std::string &filename, unsigned int lineNumber,
const std::string &funcname)
{
std::list<ErrorMessage::FileLocation> locationList;
if (!filename.empty()) {
ErrorMessage::FileLocation fileLoc;
fileLoc.setfile(filename);
fileLoc.line = lineNumber;
locationList.push_back(fileLoc);
}
const ErrorMessage errmsg(locationList, emptyString, Severity::style, "$symbol:" + funcname + "\nThe function '$symbol' is never used.", "unusedFunction", CWE561, Certainty::normal);
if (errorLogger)
errorLogger->reportErr(errmsg);
else
reportError(errmsg);
}
Check::FileInfo *CheckUnusedFunctions::getFileInfo(const Tokenizer *tokenizer, const Settings *settings) const
{
if (!settings->checks.isEnabled(Checks::unusedFunction))
return nullptr;
if (settings->jobs == 1 && settings->buildDir.empty())
instance.parseTokens(*tokenizer, tokenizer->list.getFiles().front().c_str(), settings);
return nullptr;
}
bool CheckUnusedFunctions::analyseWholeProgram(const CTU::FileInfo *ctu, const std::list<Check::FileInfo*> &fileInfo, const Settings& settings, ErrorLogger &errorLogger)
{
(void)ctu;
(void)fileInfo;
return check(&errorLogger, settings);
}
CheckUnusedFunctions::FunctionDecl::FunctionDecl(const Function *f)
: functionName(f->name()), lineNumber(f->token->linenr())
{}
std::string CheckUnusedFunctions::analyzerInfo() const
{
std::ostringstream ret;
for (const FunctionDecl &functionDecl : mFunctionDecl) {
ret << " <functiondecl"
<< " 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(const std::string &f, const int l) : fileName(f), lineNumber(l) {}
std::string fileName;
int lineNumber;
};
}
void CheckUnusedFunctions::analyseWholeProgram(ErrorLogger * const 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;
if (std::strcmp(e2->Name(),"functioncall") == 0) {
calls.insert(functionName);
continue;
} else if (std::strcmp(e2->Name(),"functiondecl") == 0) {
const char* lineNumber = e2->Attribute("lineNumber");
if (lineNumber)
decls[functionName] = Location(sourcefile, std::atoi(lineNumber));
}
}
}
}
for (std::map<std::string, Location>::const_iterator decl = decls.begin(); decl != decls.end(); ++decl) {
const std::string &functionName = decl->first;
if (functionName == "main" || functionName == "WinMain" || functionName == "_tmain" ||
functionName == "if")
continue;
if (calls.find(functionName) == calls.end() && !isOperatorFunction(functionName)) {
const Location &loc = decl->second;
unusedFunctionError(errorLogger, loc.fileName, loc.lineNumber, functionName);
}
}
}