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cppcheck/lib/checkother.cpp

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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2012 Daniel Marjamäki and 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 "checkother.h"
#include "mathlib.h"
#include "symboldatabase.h"
#include <cmath> // fabs()
#include <stack>
#include <algorithm> // find_if()
//---------------------------------------------------------------------------
// Register this check class (by creating a static instance of it)
namespace {
CheckOther instance;
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
void CheckOther::checkIncrementBoolean()
{
if (!_settings->isEnabled("style"))
return;
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::Match(tok, "%var% ++")) {
if (tok->varId()) {
const Variable *var = symbolDatabase->getVariableFromVarId(tok->varId());
if (var && var->typeEndToken()->str() == "bool")
incrementBooleanError(tok);
}
}
}
}
void CheckOther::incrementBooleanError(const Token *tok)
{
reportError(
tok,
Severity::style,
"incrementboolean",
"The use of a variable of type bool with the ++ postfix operator is always true and deprecated by the C++ Standard.\n"
"The operand of a postfix increment operator may be of type bool but it is deprecated by C++ Standard (Annex D-1) and the operand is always set to true."
);
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
void CheckOther::clarifyCalculation()
{
if (!_settings->isEnabled("style"))
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (tok->str() == "?" && tok->previous()) {
// condition
const Token *cond = tok->previous();
if (cond->isName() || cond->isNumber())
cond = cond->previous();
else if (cond->str() == ")")
cond = cond->link()->previous();
else
continue;
if (cond && cond->str() == "!")
cond = cond->previous();
if (!cond)
continue;
// calculation
if (!cond->isArithmeticalOp())
continue;
const std::string &op = cond->str();
cond = cond->previous();
// skip previous multiplications..
while (cond && cond->previous()) {
if ((cond->isName() || cond->isNumber()) && cond->previous()->str() == "*")
cond = cond->tokAt(-2);
else if (cond->str() == ")")
cond = cond->link()->previous();
else
break;
}
if (!cond)
continue;
// first multiplication operand
if (cond->str() == ")") {
clarifyCalculationError(cond, op);
} else if (cond->isName() || cond->isNumber()) {
if (Token::Match(cond->previous(),"return|=|+|-|,|(") || cond->strAt(-1) == op)
clarifyCalculationError(cond, op);
}
}
}
}
void CheckOther::clarifyCalculationError(const Token *tok, const std::string &op)
{
// suspicious calculation
const std::string calc("'a" + op + "b?c:d'");
// recommended calculation #1
const std::string s1("'(a" + op + "b)?c:d'");
// recommended calculation #2
const std::string s2("'a" + op + "(b?c:d)'");
reportError(tok,
Severity::style,
"clarifyCalculation",
"Clarify calculation precedence for " + op + " and ?\n"
"Suspicious calculation. Please use parentheses to clarify the code. "
"The code " + calc + " should be written as either " + s1 + " or " + s2 + ".");
}
//---------------------------------------------------------------------------
// Clarify condition '(x = a < 0)' into '((x = a) < 0)' or '(x = (a < 0))'
// Clarify condition '(a & b == c)' into '((a & b) == c)' or '(a & (b == c))'
//---------------------------------------------------------------------------
void CheckOther::clarifyCondition()
{
if (!_settings->isEnabled("style"))
return;
const bool isC = _tokenizer->isC();
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::Match(tok, "( %var% [=&|^]")) {
for (const Token *tok2 = tok->tokAt(3); tok2; tok2 = tok2->next()) {
if (tok2->str() == "(" || tok2->str() == "[")
tok2 = tok2->link();
else if (tok2->type() == Token::eComparisonOp) {
// This might be a template
if (!isC && tok2->link())
break;
clarifyConditionError(tok, tok->strAt(2) == "=", false);
break;
} else if (!tok2->isName() && !tok2->isNumber() && tok2->str() != ".")
break;
}
}
}
// using boolean result in bitwise operation ! x [&|^]
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::Match(tok, "!|<|<=|==|!=|>|>=")) {
if (tok->link()) // don't write false positives when templates are used
continue;
const Token *tok2 = tok->next();
// Todo: There are false positives if '(' if encountered. It
// is assumed there is something like '(char *)&..' and therefore
// it bails out.
if (Token::Match(tok2, "(|&"))
continue;
while (tok2 && (tok2->isName() || tok2->isNumber() || Token::Match(tok2,".|(|["))) {
if (Token::Match(tok2, "(|["))
tok2 = tok2->link();
tok2 = tok2->next();
}
if (Token::Match(tok2, "[&|^]")) {
// don't write false positives when templates are used
if (Token::Match(tok2, "&|* ,|>") || Token::simpleMatch(tok2->previous(), "const &"))
continue;
// #3609 - CWinTraits<WS_CHILD|WS_VISIBLE>::..
if (!isC && Token::Match(tok->previous(), "%var% <")) {
const Token *tok3 = tok2;
while (Token::Match(tok3, "[&|^] %var%"))
tok3 = tok3->tokAt(2);
if (Token::Match(tok3, ",|>"))
continue;
}
clarifyConditionError(tok,false,true);
}
}
}
}
void CheckOther::clarifyConditionError(const Token *tok, bool assign, bool boolop)
{
std::string errmsg;
if (assign)
errmsg = "Suspicious condition (assignment+comparison), it can be clarified with parentheses";
else if (boolop)
errmsg = "Boolean result is used in bitwise operation. Clarify expression with parentheses\n"
"Suspicious expression. Boolean result is used in bitwise operation. The ! operator "
"and the comparison operators have higher precedence than bitwise operators. "
"It is recommended that the expression is clarified with parentheses.";
else
errmsg = "Suspicious condition (bitwise operator + comparison), it can be clarified with parentheses\n"
"Suspicious condition. Comparison operators have higher precedence than bitwise operators. Please clarify the condition with parentheses.";
reportError(tok,
Severity::style,
"clarifyCondition",
errmsg);
}
//---------------------------------------------------------------------------
// Clarify (meaningless) statements like *foo++; with parantheses.
//---------------------------------------------------------------------------
void CheckOther::clarifyStatement()
{
if (!_settings->isEnabled("style"))
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::Match(tok, "* %var%")) {
const Token *tok2=tok->previous();
while (Token::Match(tok2, "*"))
tok2=tok2->previous();
if (Token::Match(tok2, "[{};]")) {
tok = tok->tokAt(2);
while (tok) {
if (tok->str() == "[")
tok = tok->link()->next();
if (Token::Match(tok, ".|:: %var%")) {
if (tok->strAt(2) == "(")
tok = tok->linkAt(2)->next();
else
tok = tok->tokAt(2);
} else
break;
}
if (Token::Match(tok, "++|-- [;,]"))
//TODO: change the string in order to remove the excessive spaces between the tokens.
clarifyStatementError(tok,
tok2->next()->stringifyList(tok->tokAt(2)),
"("+tok2->next()->stringifyList(tok)+")"+tok->stringifyList(tok->tokAt(2)));
}
}
}
}
void CheckOther::clarifyStatementError(const Token *tok, const std::string &expr, const std::string &suggested)
{
reportError(tok, Severity::warning, "clarifyStatement", "Ineffective statement: '" + expr + "'. Did you intend to write '" + suggested + "'?\n"
"A statement like '*expr++;' might not do what you intended. 'operator*' is executed before postfix 'operator++'. "
"Thus, the dereference is meaningless. Did you intend to write '(*expr)++;'?");
}
//---------------------------------------------------------------------------
// if (bool & bool) -> if (bool && bool)
// if (bool | bool) -> if (bool || bool)
//---------------------------------------------------------------------------
void CheckOther::checkBitwiseOnBoolean()
{
if (!_settings->isEnabled("style"))
return;
// danmar: this is inconclusive because I don't like that there are
// warnings for calculations. Example: set_flag(a & b);
if (!_settings->inconclusive)
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::Match(tok, "(|.|return|&&|%oror%|throw|, %var% [&|]")) {
const Variable *var = _tokenizer->getSymbolDatabase()->getVariableFromVarId(tok->next()->varId());
if (var && var->typeEndToken()->str() == "bool") {
bitwiseOnBooleanError(tok->next(), var->name(), tok->strAt(2) == "&" ? "&&" : "||");
tok = tok->tokAt(2);
}
} else if (Token::Match(tok, "[&|] %var% )|.|return|&&|%oror%|throw|,") && (!tok->previous() || !tok->previous()->isExtendedOp() || tok->strAt(-1) == ")")) {
const Variable *var = _tokenizer->getSymbolDatabase()->getVariableFromVarId(tok->next()->varId());
if (var && var->typeEndToken()->str() == "bool") {
bitwiseOnBooleanError(tok->next(), var->name(), tok->str() == "&" ? "&&" : "||");
tok = tok->tokAt(2);
}
}
}
}
void CheckOther::bitwiseOnBooleanError(const Token *tok, const std::string &varname, const std::string &op)
{
reportError(tok, Severity::style, "bitwiseOnBoolean",
"Boolean variable '" + varname + "' is used in bitwise operation. Did you mean " + op + " ?", true);
}
void CheckOther::checkSuspiciousSemicolon()
{
if (!_settings->inconclusive || !_settings->isEnabled("style"))
return;
const SymbolDatabase* const symbolDatabase = _tokenizer->getSymbolDatabase();
// Look for "if(); {}", "for(); {}" or "while(); {}"
for (std::list<Scope>::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) {
if (i->type == Scope::eIf || i->type == Scope::eElse || i->type == Scope::eElseIf || i->type == Scope::eWhile || i->type == Scope::eFor) {
// Ensure the semicolon is at the same line number as the if/for/while statement
// and the {..} block follows it without an extra empty line.
if (Token::simpleMatch(i->classStart, "{ ; } {") &&
i->classStart->previous()->linenr() == i->classStart->tokAt(2)->linenr()
&& i->classStart->linenr()+1 >= i->classStart->tokAt(3)->linenr()) {
SuspiciousSemicolonError(i->classStart);
}
}
}
}
void CheckOther::SuspiciousSemicolonError(const Token* tok)
{
reportError(tok, Severity::warning, "suspiciousSemicolon",
"Suspicious use of ; at the end of 'if/for/while' statement.", true);
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
void CheckOther::warningOldStylePointerCast()
{
// Only valid on C++ code
if (!_settings->isEnabled("style") || !_tokenizer->isCPP())
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
// Old style pointer casting..
if (!Token::Match(tok, "( const| %type% * ) (| %var%") &&
!Token::Match(tok, "( const| %type% * ) (| new"))
continue;
if (tok->strAt(1) == "const")
tok = tok->next();
if (tok->strAt(4) == "const")
continue;
// Is "type" a class?
const std::string pattern("class|struct " + tok->strAt(1));
if (Token::findmatch(_tokenizer->tokens(), pattern.c_str(), tok))
cstyleCastError(tok);
}
}
void CheckOther::cstyleCastError(const Token *tok)
{
reportError(tok, Severity::style, "cstyleCast", "C-style pointer casting");
}
//---------------------------------------------------------------------------
// float* f; double* d = (double*)f; <-- Pointer cast to a type with an incompatible binary data representation
//---------------------------------------------------------------------------
static std::string analyzeType(const Token* tok)
{
if (tok->str() == "double") {
if (tok->isLong())
return "long double";
else
return "double";
}
if (tok->str() == "float")
return "float";
if (Token::Match(tok, "int|long|short|char|size_t"))
return "integer";
return "";
}
void CheckOther::invalidPointerCast()
{
if (!_settings->isEnabled("style") && !_settings->isEnabled("portability"))
return;
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
const Token* toTok = 0;
const Token* nextTok = 0;
// Find cast
if (Token::Match(tok, "( const| %type% const| * )") || Token::Match(tok, "( const| %type% %type% const| * )")) {
toTok = tok->next();
nextTok = tok->link()->next();
if (nextTok && nextTok->str() == "(")
nextTok = nextTok->next();
} else if (Token::Match(tok, "reinterpret_cast < const| %type% const| * > (") || Token::Match(tok, "reinterpret_cast < const| %type% %type% const| * > (")) {
nextTok = tok->tokAt(5);
while (nextTok->str() != "(")
nextTok = nextTok->next();
nextTok = nextTok->next();
toTok = tok->tokAt(2);
}
if (toTok && toTok->str() == "const")
toTok = toTok->next();
if (!nextTok || !toTok || !toTok->isStandardType())
continue;
// Find casted variable
unsigned int varid = 0;
bool allocation = false;
bool ref = false;
if (Token::Match(nextTok, "new %type%"))
allocation = true;
else if (Token::Match(nextTok, "%var% !!["))
varid = nextTok->varId();
else if (Token::Match(nextTok, "& %var%") && !Token::Match(nextTok->tokAt(2), "(|[")) {
varid = nextTok->next()->varId();
ref = true;
}
const Token* fromTok = 0;
if (allocation) {
fromTok = nextTok->next();
} else {
const Variable* var = symbolDatabase->getVariableFromVarId(varid);
if (!var || (!ref && !var->isPointer() && !var->isArray()) || (ref && (var->isPointer() || var->isArray())))
continue;
fromTok = var->typeStartToken();
}
while (Token::Match(fromTok, "static|const"))
fromTok = fromTok->next();
if (!fromTok->isStandardType())
continue;
std::string fromType = analyzeType(fromTok);
std::string toType = analyzeType(toTok);
if (fromType != toType && !fromType.empty() && !toType.empty() && (toType != "integer" || _settings->isEnabled("portability")) && (toTok->str() != "char" || _settings->inconclusive))
invalidPointerCastError(tok, fromType, toType, toTok->str() == "char");
}
}
void CheckOther::invalidPointerCastError(const Token* tok, const std::string& from, const std::string& to, bool inconclusive)
{
if (to == "integer") { // If we cast something to int*, this can be useful to play with its binary data representation
if (!inconclusive)
reportError(tok, Severity::portability, "invalidPointerCast", "Casting from " + from + "* to integer* is not portable due to different binary data representations on different platforms");
else
reportError(tok, Severity::portability, "invalidPointerCast", "Casting from " + from + "* to char* might be not portable due to different binary data representations on different platforms", true);
} else
reportError(tok, Severity::warning, "invalidPointerCast", "Casting between " + from + "* and " + to + "* which have an incompatible binary data representation");
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
void CheckOther::checkSizeofForNumericParameter()
{
if (!_settings->isEnabled("style"))
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::Match(tok, "sizeof ( %num% )")
|| Token::Match(tok, "sizeof %num%")
) {
sizeofForNumericParameterError(tok);
}
}
}
void CheckOther::sizeofForNumericParameterError(const Token *tok)
{
reportError(tok, Severity::warning,
"sizeofwithnumericparameter", "Using sizeof with a numeric constant as function "
"argument might not be what you intended.\n"
"It is unusual to use constant value with sizeof. For example, sizeof(10)"
" returns 4 (in 32-bit systems) or 8 (in 64-bit systems) instead of 10. sizeof('A')"
" and sizeof(char) can return different results.");
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
void CheckOther::checkSizeofForArrayParameter()
{
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::Match(tok, "sizeof ( %var% )") || Token::Match(tok, "sizeof %var% !![")) {
const Token* varTok = tok->next();
if (varTok->str() == "(") {
varTok = varTok->next();
}
if (varTok->varId() > 0) {
const Variable *var = symbolDatabase->getVariableFromVarId(varTok->varId());
if (var && var->isArray() && var->isArgument()) {
sizeofForArrayParameterError(tok);
}
}
}
}
}
void CheckOther::sizeofForArrayParameterError(const Token *tok)
{
reportError(tok, Severity::error,
"sizeofwithsilentarraypointer", "Using sizeof for array given as function argument "
"returns the size of pointer.\n"
"Giving array as function parameter and then using sizeof-operator for the array "
"argument. In this case the sizeof-operator returns the size of pointer (in the "
"system). It does not return the size of the whole array in bytes as might be "
"expected. For example, this code:\n"
" int f(char a[100]) {\n"
" return sizeof(a);\n"
" }\n"
" returns 4 (in 32-bit systems) or 8 (in 64-bit systems) instead of 100 (the "
"size of the array in bytes)."
);
}
void CheckOther::checkSizeofForPointerSize()
{
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
if (!_settings->isEnabled("style"))
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
const Token *tokVar;
const Token *variable;
const Token *variable2 = 0;
// Find any function that may use sizeof on a pointer
// Once leaving those tests, it is mandatory to have:
// - variable matching the used pointer
// - tokVar pointing on the argument where sizeof may be used
if (Token::Match(tok, "[*;{}] %var% = malloc|alloca (")) {
variable = tok->next();
tokVar = tok->tokAt(5);
} else if (Token::Match(tok, "[*;{}] %var% = calloc (")) {
variable = tok->next();
tokVar = tok->tokAt(5)->nextArgument();
} else if (Token::simpleMatch(tok, "memset (")) {
variable = tok->tokAt(2);
tokVar = variable->tokAt(2)->nextArgument();
// The following tests can be inconclusive in case the variable in sizeof
// is constant string by intention
} else if (!_settings->inconclusive) {
continue;
} else if (Token::Match(tok, "memcpy|memcmp|memmove|strncpy|strncmp|strncat (")) {
variable = tok->tokAt(2);
variable2 = variable->nextArgument();
tokVar = variable2->nextArgument();
} else {
continue;
}
// Ensure the variables are in the symbol database
// Also ensure the variables are pointers
// Only keep variables which are pointers
const Variable *var = symbolDatabase->getVariableFromVarId(variable->varId());
if (!var || !var->isPointer() || var->isArray()) {
variable = 0;
}
if (variable2) {
var = symbolDatabase->getVariableFromVarId(variable2->varId());
if (!var || !var->isPointer() || var->isArray()) {
variable2 = 0;
}
}
// If there are no pointer variable at this point, there is
// no need to continue
if (variable == 0 && variable2 == 0) {
continue;
}
// Jump to the next sizeof token in the function and in the parameter
// This is to allow generic operations with sizeof
for (; tokVar && tokVar->str() != ")" && tokVar->str() != "," && tokVar->str() != "sizeof"; tokVar = tokVar->next()) {}
// Now check for the sizeof usage. Once here, everything using sizeof(varid) or sizeof(&varid)
// looks suspicious
// Do it for first variable
if (variable && (Token::Match(tokVar, "sizeof ( &| %varid% )", variable->varId()) ||
Token::Match(tokVar, "sizeof &| %varid%", variable->varId()))) {
sizeofForPointerError(variable, variable->str());
} else if (variable2 && (Token::Match(tokVar, "sizeof ( &| %varid% )", variable2->varId()) ||
Token::Match(tokVar, "sizeof &| %varid%", variable2->varId()))) {
sizeofForPointerError(variable2, variable2->str());
}
}
}
void CheckOther::sizeofForPointerError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::warning, "pointerSize",
"Using size of pointer " + varname + " instead of size of its data.\n"
"Using size of pointer " + varname + " instead of size of its data. "
"This is likely to lead to a buffer overflow. You probably intend to "
"write sizeof(*" + varname + ")", true);
}
//---------------------------------------------------------------------------
// Detect redundant assignments: x = 0; x = 4;
//---------------------------------------------------------------------------
static void eraseNotLocalArg(std::map<unsigned int, const Token*>& container, const SymbolDatabase* symbolDatabase)
{
for (std::map<unsigned int, const Token*>::iterator i = container.begin(); i != container.end();) {
const Variable* var = symbolDatabase->getVariableFromVarId(i->first);
if (!var || (!var->isLocal() && !var->isArgument())) {
container.erase(i++);
if (i == container.end())
break;
} else
++i;
}
}
void CheckOther::checkRedundantAssignment()
{
if (!_settings->isEnabled("performance"))
return;
const SymbolDatabase* symbolDatabase = _tokenizer->getSymbolDatabase();
for (std::list<Scope>::const_iterator scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {
if (!scope->isExecutable())
continue;
///std::cout << std::endl << "scope: " << i->className << std::endl;
std::map<unsigned int, const Token*> varAssignments;
std::map<unsigned int, const Token*> memAssignments;
const Token* writtenArgumentsEnd = 0;
for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) {
if (tok == writtenArgumentsEnd)
writtenArgumentsEnd = 0;
if (tok->str() == "{" && tok->strAt(-1) != "{" && tok->strAt(-1) != "=" && tok->strAt(-4) != "case" && tok->strAt(-3) != "default") { // conditional or non-executable inner scope: Skip it and reset status
tok = tok->link();
varAssignments.clear();
memAssignments.clear();
} else if (Token::Match(tok, "for|if|while (")) {
tok = tok->linkAt(1);
} else if (Token::Match(tok, "break|return|continue|throw|goto")) {
varAssignments.clear();
memAssignments.clear();
} else if (tok->type() == Token::eVariable) {
std::map<unsigned int, const Token*>::iterator it = varAssignments.find(tok->varId());
if (tok->next()->isAssignmentOp() && Token::Match(tok->previous(), "[;{}]")) { // Assignment
///std::cout << "assign: " << tok->varId() << std::endl;
if (it != varAssignments.end()) {
bool error = true; // Ensure that variable is not used on right side
for (const Token* tok2 = tok->tokAt(2); tok2; tok2 = tok2->next()) {
if (tok2->str() == ";")
break;
else if (tok2->varId() == tok->varId())
error = false;
}
if (error) {
if (scope->type == Scope::eSwitch && Token::findmatch(it->second, "default|case", tok))
redundantAssignmentInSwitchError(it->second, tok, tok->str());
else
redundantAssignmentError(it->second, tok, tok->str());
}
it->second = tok;
}
varAssignments[tok->varId()] = tok;
memAssignments.erase(tok->varId());
} else if (tok->next()->type() == Token::eIncDecOp || (tok->previous()->type() == Token::eIncDecOp && !Token::Match(tok->next(), ".|[|("))) { // Variable incremented/decremented
varAssignments[tok->varId()] = tok;
memAssignments.erase(tok->varId());
} else if (!Token::Match(tok->tokAt(-2), "sizeof (")) { // Other usage of variable
///std::cout << "use: " << tok->varId() << std::endl;
if (it != varAssignments.end())
varAssignments.erase(it);
if (!writtenArgumentsEnd) // Indicates that we are in the first argument of strcpy/memcpy/... function
memAssignments.erase(tok->varId());
}
} else if (Token::Match(tok, "%var% (")) { // Function call. Global variables might be used. Reset their status
bool memfunc = Token::Match(tok, "memcpy|memmove|memset|strcpy|strncpy|sprintf|snprintf|strcat|strncat");
if (memfunc) {
const Token* param1 = tok->tokAt(2);
writtenArgumentsEnd = param1->next();
if (param1->varId() && param1->strAt(1) == "," && tok->str() != "strcat" && tok->str() != "strncat") {
std::map<unsigned int, const Token*>::iterator it = memAssignments.find(param1->varId());
if (it == memAssignments.end())
memAssignments[param1->varId()] = tok;
else {
if (scope->type == Scope::eSwitch && Token::findmatch(it->second, "default|case", tok))
redundantCopyInSwitchError(it->second, tok, param1->str());
else
redundantCopyError(it->second, tok, param1->str());
}
}
} else if (scope->type == Scope::eSwitch) { // Avoid false positives if noreturn function is called in switch
const Function* func = symbolDatabase->findFunctionByToken(_tokenizer->getFunctionTokenByName(tok->str().c_str()));
if (!func || !func->hasBody) {
varAssignments.clear();
memAssignments.clear();
continue;
}
const Token* funcEnd = func->functionScope->classEnd;
bool noreturn;
if (!_tokenizer->IsScopeNoReturn(funcEnd, &noreturn) && !noreturn) {
eraseNotLocalArg(varAssignments, symbolDatabase);
eraseNotLocalArg(memAssignments, symbolDatabase);
} else {
varAssignments.clear();
memAssignments.clear();
}
} else { // Noreturn functions outside switch don't cause problems
eraseNotLocalArg(varAssignments, symbolDatabase);
eraseNotLocalArg(memAssignments, symbolDatabase);
}
}
}
}
}
void CheckOther::redundantCopyError(const Token *tok1, const Token* tok2, const std::string& var)
{
std::list<const Token*> callstack;
callstack.push_back(tok1);
callstack.push_back(tok2);
reportError(callstack, Severity::performance, "redundantCopy",
"Buffer '" + var + "' is being written before its old content has been used.");
}
void CheckOther::redundantCopyInSwitchError(const Token *tok1, const Token* tok2, const std::string &var)
{
std::list<const Token*> callstack;
callstack.push_back(tok1);
callstack.push_back(tok2);
reportError(callstack, Severity::warning, "redundantCopyInSwitch",
"Buffer '" + var + "' is being written before its old content has been used. This might indicate a missing 'break;'.");
}
void CheckOther::redundantAssignmentError(const Token *tok1, const Token* tok2, const std::string& var)
{
std::list<const Token*> callstack;
callstack.push_back(tok1);
callstack.push_back(tok2);
reportError(callstack, Severity::performance, "redundantAssignment",
"Variable '" + var + "' is reassigned a value before the old one has been used.");
}
void CheckOther::redundantAssignmentInSwitchError(const Token *tok1, const Token* tok2, const std::string &var)
{
std::list<const Token*> callstack;
callstack.push_back(tok1);
callstack.push_back(tok2);
reportError(callstack, Severity::warning, "redundantAssignInSwitch",
"Variable '" + var + "' is reassigned a value before the old one has been used. This might indicate a missing 'break;'.");
}
//---------------------------------------------------------------------------
// switch (x)
// {
// case 2:
// y = a; // <- this assignment is redundant
// case 3:
// y = b; // <- case 2 falls through and sets y twice
// }
//---------------------------------------------------------------------------
void CheckOther::checkRedundantAssignmentInSwitch()
{
if (!_settings->isEnabled("style"))
return;
const char breakPattern[] = "break|continue|return|exit|goto|throw";
const char functionPattern[] = "%var% (";
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
// Find the beginning of a switch. E.g.:
// switch (var) { ...
for (std::list<Scope>::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) {
if (i->type != Scope::eSwitch || !i->classStart)
continue;
// Check the contents of the switch statement
std::map<unsigned int, const Token*> varsWithBitsSet;
std::map<unsigned int, std::string> bitOperations;
for (const Token *tok2 = i->classStart->next(); tok2 != i->classEnd; tok2 = tok2->next()) {
if (tok2->str() == "{") {
// Inside a conditional or loop. Don't mark variable accesses as being redundant. E.g.:
// case 3: b = 1;
// case 4: if (a) { b = 2; } // Doesn't make the b=1 redundant because it's conditional
if (Token::Match(tok2->previous(), ")|else {") && tok2->link()) {
const Token* endOfConditional = tok2->link();
for (const Token* tok3 = tok2; tok3 != endOfConditional; tok3 = tok3->next()) {
if (tok3->varId() != 0) {
varsWithBitsSet.erase(tok3->varId());
bitOperations.erase(tok3->varId());
} else if (Token::Match(tok3, functionPattern) || Token::Match(tok3, breakPattern)) {
varsWithBitsSet.clear();
bitOperations.clear();
}
}
tok2 = endOfConditional;
}
}
// Variable assignment. Report an error if it's assigned to twice before a break. E.g.:
// case 3: b = 1; // <== redundant
// case 4: b = 2;
if (Token::Match(tok2->previous(), ";|{|}|: %var% = %any% ;") && tok2->varId() != 0) {
varsWithBitsSet.erase(tok2->varId());
bitOperations.erase(tok2->varId());
}
// Bitwise operation. Report an error if it's performed twice before a break. E.g.:
// case 3: b |= 1; // <== redundant
// case 4: b |= 1;
else if (Token::Match(tok2->previous(), ";|{|}|: %var% = %var% %or%|& %num% ;") &&
tok2->varId() != 0 && tok2->varId() == tok2->tokAt(2)->varId()) {
std::string bitOp = tok2->strAt(3) + tok2->strAt(4);
std::map<unsigned int, const Token*>::iterator i2 = varsWithBitsSet.find(tok2->varId());
// This variable has not had a bit operation performed on it yet, so just make a note of it
if (i2 == varsWithBitsSet.end()) {
varsWithBitsSet[tok2->varId()] = tok2;
bitOperations[tok2->varId()] = bitOp;
}
// The same bit operation has been performed on the same variable twice, so report an error
else if (bitOperations[tok2->varId()] == bitOp)
redundantBitwiseOperationInSwitchError(i2->second, i2->second->str());
// A different bit operation was performed on the variable, so clear it
else {
varsWithBitsSet.erase(tok2->varId());
bitOperations.erase(tok2->varId());
}
}
// Not a simple assignment so there may be good reason if this variable is assigned to twice. E.g.:
// case 3: b = 1;
// case 4: b++;
else if (tok2->varId() != 0 && tok2->strAt(1) != "|" && tok2->strAt(1) != "&") {
varsWithBitsSet.erase(tok2->varId());
bitOperations.erase(tok2->varId());
}
// Reset our record of assignments if there is a break or function call. E.g.:
// case 3: b = 1; break;
if (Token::Match(tok2, functionPattern) || Token::Match(tok2, breakPattern)) {
varsWithBitsSet.clear();
bitOperations.clear();
}
}
}
}
void CheckOther::redundantBitwiseOperationInSwitchError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::warning,
"redundantBitwiseOperationInSwitch", "Redundant bitwise operation on \"" + varname + "\" in switch");
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
void CheckOther::checkSwitchCaseFallThrough()
{
if (!(_settings->isEnabled("style") && _settings->experimental))
return;
const SymbolDatabase* const symbolDatabase = _tokenizer->getSymbolDatabase();
const char breakPattern[] = "break|continue|return|exit|goto|throw";
for (std::list<Scope>::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) {
if (i->type != Scope::eSwitch || !i->classStart) // Find the beginning of a switch
continue;
// Check the contents of the switch statement
std::stack<std::pair<Token *, bool> > ifnest;
std::stack<Token *> loopnest;
std::stack<Token *> scopenest;
bool justbreak = true;
bool firstcase = true;
for (const Token *tok2 = i->classStart; tok2 != i->classEnd; tok2 = tok2->next()) {
if (Token::simpleMatch(tok2, "if (")) {
tok2 = tok2->next()->link()->next();
if (tok2->link() == NULL) {
std::ostringstream errmsg;
errmsg << "unmatched if in switch: " << tok2->linenr();
reportError(_tokenizer->tokens(), Severity::debug, "debug", errmsg.str());
break;
}
ifnest.push(std::make_pair(tok2->link(), false));
justbreak = false;
} else if (Token::simpleMatch(tok2, "while (")) {
tok2 = tok2->next()->link()->next();
// skip over "do { } while ( ) ;" case
if (tok2->str() == "{") {
if (tok2->link() == NULL) {
std::ostringstream errmsg;
errmsg << "unmatched while in switch: " << tok2->linenr();
reportError(_tokenizer->tokens(), Severity::debug, "debug", errmsg.str());
break;
}
loopnest.push(tok2->link());
}
justbreak = false;
} else if (Token::simpleMatch(tok2, "do {")) {
tok2 = tok2->next();
if (tok2->link() == NULL) {
std::ostringstream errmsg;
errmsg << "unmatched do in switch: " << tok2->linenr();
reportError(_tokenizer->tokens(), Severity::debug, "debug", errmsg.str());
break;
}
loopnest.push(tok2->link());
justbreak = false;
} else if (Token::simpleMatch(tok2, "for (")) {
tok2 = tok2->next()->link()->next();
if (tok2->link() == NULL) {
std::ostringstream errmsg;
errmsg << "unmatched for in switch: " << tok2->linenr();
reportError(_tokenizer->tokens(), Severity::debug, "debug", errmsg.str());
break;
}
loopnest.push(tok2->link());
justbreak = false;
} else if (Token::simpleMatch(tok2, "switch (")) {
// skip over nested switch, we'll come to that soon
tok2 = tok2->next()->link()->next()->link();
} else if (Token::Match(tok2, breakPattern)) {
if (loopnest.empty()) {
justbreak = true;
}
tok2 = Token::findsimplematch(tok2, ";");
} else if (Token::Match(tok2, "case|default")) {
if (!justbreak && !firstcase) {
switchCaseFallThrough(tok2);
}
tok2 = Token::findsimplematch(tok2, ":");
justbreak = true;
firstcase = false;
} else if (tok2->str() == "{") {
scopenest.push(tok2->link());
} else if (tok2->str() == "}") {
if (!ifnest.empty() && tok2 == ifnest.top().first) {
if (tok2->next()->str() == "else") {
tok2 = tok2->tokAt(2);
ifnest.pop();
if (tok2->link() == NULL) {
std::ostringstream errmsg;
errmsg << "unmatched if in switch: " << tok2->linenr();
reportError(_tokenizer->tokens(), Severity::debug, "debug", errmsg.str());
break;
}
ifnest.push(std::make_pair(tok2->link(), justbreak));
justbreak = false;
} else {
justbreak &= ifnest.top().second;
ifnest.pop();
}
} else if (!loopnest.empty() && tok2 == loopnest.top()) {
loopnest.pop();
} else if (!scopenest.empty() && tok2 == scopenest.top()) {
scopenest.pop();
} else {
if (!ifnest.empty() || !loopnest.empty() || !scopenest.empty()) {
std::ostringstream errmsg;
errmsg << "unexpected end of switch: ";
errmsg << "ifnest=" << ifnest.size();
if (!ifnest.empty())
errmsg << "," << ifnest.top().first->linenr();
errmsg << ", loopnest=" << loopnest.size();
if (!loopnest.empty())
errmsg << "," << loopnest.top()->linenr();
errmsg << ", scopenest=" << scopenest.size();
if (!scopenest.empty())
errmsg << "," << scopenest.top()->linenr();
reportError(_tokenizer->tokens(), Severity::debug, "debug", errmsg.str());
}
// end of switch block
break;
}
} else if (tok2->str() != ";") {
justbreak = false;
}
}
}
}
void CheckOther::switchCaseFallThrough(const Token *tok)
{
reportError(tok, Severity::style,
"switchCaseFallThrough", "Switch falls through case without comment");
}
//---------------------------------------------------------------------------
// int x = 1;
// x = x; // <- redundant assignment to self
//
// int y = y; // <- redundant initialization to self
//---------------------------------------------------------------------------
static bool isTypeWithoutSideEffects(const Tokenizer *tokenizer, const Variable* var)
{
return ((var && (!var->isClass() || var->isPointer() || Token::simpleMatch(var->typeStartToken(), "std ::"))) || !tokenizer->isCPP());
}
void CheckOther::checkSelfAssignment()
{
if (!_settings->isEnabled("style"))
return;
const SymbolDatabase* symbolDatabase = _tokenizer->getSymbolDatabase();
const char selfAssignmentPattern[] = "%var% = %var% ;|=|)";
const Token *tok = Token::findmatch(_tokenizer->tokens(), selfAssignmentPattern);
while (tok) {
if (Token::Match(tok->previous(), "[;{}]") &&
tok->varId() && tok->varId() == tok->tokAt(2)->varId() &&
isTypeWithoutSideEffects(_tokenizer, symbolDatabase->getVariableFromVarId(tok->varId()))) {
bool err = true;
// no false positive for 'x = x ? x : 1;'
// it is simplified to 'if (x) { x=x; } else { x=1; }'. The simplification
// always write all tokens on 1 line (even if the statement is several lines), so
// check if the linenr is the same for all the tokens.
if (Token::Match(tok->tokAt(-2), ") { %var% = %var% ; } else { %varid% =", tok->varId())) {
// Find the 'if' token
const Token *tokif = tok->linkAt(-2)->previous();
// find the '}' that terminates the 'else'-block
const Token *else_end = tok->linkAt(6);
if (tokif && else_end && tokif->linenr() == else_end->linenr())
err = false;
}
if (err)
selfAssignmentError(tok, tok->str());
}
tok = Token::findmatch(tok->next(), selfAssignmentPattern);
}
}
void CheckOther::selfAssignmentError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::warning,
"selfAssignment", "Redundant assignment of \"" + varname + "\" to itself");
}
//---------------------------------------------------------------------------
// int a = 1;
// assert(a = 2); // <- assert should not have a side-effect
//---------------------------------------------------------------------------
void CheckOther::checkAssignmentInAssert()
{
if (!_settings->isEnabled("style"))
return;
const char assertPattern[] = "assert ( %any%";
const Token *tok = Token::findmatch(_tokenizer->tokens(), assertPattern);
const Token *endTok = tok ? tok->next()->link() : NULL;
while (tok && endTok) {
for (tok = tok->tokAt(2); tok != endTok; tok = tok->next()) {
if (tok->isName() && (tok->next()->isAssignmentOp() || tok->next()->type() == Token::eIncDecOp))
assignmentInAssertError(tok, tok->str());
else if (Token::Match(tok, "--|++ %var%"))
assignmentInAssertError(tok, tok->strAt(1));
}
tok = Token::findmatch(endTok->next(), assertPattern);
endTok = tok ? tok->next()->link() : NULL;
}
}
void CheckOther::assignmentInAssertError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::warning,
"assignmentInAssert", "Assert statement modifies '" + varname + "'.\n"
"Variable '" + varname + "' is modified insert assert statement. "
"Assert statements are removed from release builds so the code inside "
"assert statement is not run. If the code is needed also in release "
"builds this is a bug.");
}
//---------------------------------------------------------------------------
// if ((x != 1) || (x != 3)) // expression always true
// if ((x == 1) && (x == 3)) // expression always false
// if ((x < 1) && (x > 3)) // expression always false
// if ((x > 3) || (x < 10)) // expression always true
// if ((x > 5) && (x != 1)) // second comparison always true
//
// Check for suspect logic for an expression consisting of 2 comparison
// expressions with a shared variable and constants and a logical operator
// between them.
//
// Suggest a different logical operator when the logical operator between
// the comparisons is probably wrong.
//
// Inform that second comparison is always true when first comparison is true.
//---------------------------------------------------------------------------
enum Position { First, Second, NA };
enum Relation { Equal, NotEqual, Less, LessEqual, More, MoreEqual };
struct Condition {
Position position;
const char *opTokStr;
};
static std::string invertOperatorForOperandSwap(std::string s)
{
for (std::string::size_type i = 0; i < s.length(); i++) {
if (s[i] == '>')
s[i] = '<';
else if (s[i] == '<')
s[i] = '>';
}
return s;
}
static bool analyzeLogicOperatorCondition(const Condition& c1, const Condition& c2,
bool inv1, bool inv2,
bool varFirst1, bool varFirst2,
const std::string& firstConstant, const std::string& secondConstant,
const Token* op1Tok, const Token* op3Tok,
Relation relation)
{
if (!(c1.position == NA || (c1.position == First && varFirst1) || (c1.position == Second && !varFirst1)))
return false;
if (!(c2.position == NA || (c2.position == First && varFirst2) || (c2.position == Second && !varFirst2)))
return false;
if (!Token::Match(op1Tok, inv1?invertOperatorForOperandSwap(c1.opTokStr).c_str():c1.opTokStr))
return false;
if (!Token::Match(op3Tok, inv2?invertOperatorForOperandSwap(c2.opTokStr).c_str():c2.opTokStr))
return false;
return (relation == Equal && MathLib::isEqual(firstConstant, secondConstant)) ||
(relation == NotEqual && MathLib::isNotEqual(firstConstant, secondConstant)) ||
(relation == Less && MathLib::isLess(firstConstant, secondConstant)) ||
(relation == LessEqual && MathLib::isLessEqual(firstConstant, secondConstant)) ||
(relation == More && MathLib::isGreater(firstConstant, secondConstant)) ||
(relation == MoreEqual && MathLib::isGreaterEqual(firstConstant, secondConstant));
}
void CheckOther::checkIncorrectLogicOperator()
{
if (!_settings->isEnabled("style"))
return;
for (const Token* tok = _tokenizer->tokens(); tok; tok = tok->next()) {
// Find a pair of comparison expressions with or without parenthesis
// with a shared variable and constants and with a logical operator between them.
// e.g. if (x != 3 || x != 4)
const Token *term1Tok = NULL, *term2Tok = NULL;
const Token *op1Tok = NULL, *op2Tok = NULL, *op3Tok = NULL, *nextTok = NULL;
if (Token::Match(tok, "( %any% !=|==|<|>|>=|<= %any% ) &&|%oror%")) {
term1Tok = tok->next();
op1Tok = tok->tokAt(2);
op2Tok = tok->tokAt(5);
} else if (Token::Match(tok, "%any% !=|==|<|>|>=|<= %any% &&|%oror%")) {
term1Tok = tok;
op1Tok = tok->next();
op2Tok = tok->tokAt(3);
}
if (op2Tok) {
if (Token::Match(op2Tok->next(), "( %any% !=|==|<|>|>=|<= %any% ) %any%")) {
term2Tok = op2Tok->tokAt(2);
op3Tok = op2Tok->tokAt(3);
nextTok = op2Tok->tokAt(6);
} else if (Token::Match(op2Tok->next(), "%any% !=|==|<|>|>=|<= %any% %any%")) {
term2Tok = op2Tok->next();
op3Tok = op2Tok->tokAt(2);
nextTok = op2Tok->tokAt(4);
}
}
if (nextTok) {
// Find the common variable and the two different-valued constants
std::string firstConstant, secondConstant;
bool varFirst1, varFirst2;
unsigned int varId;
const Token *var1Tok = NULL, *var2Tok = NULL;
if (Token::Match(term1Tok, "%var% %any% %num%")) {
var1Tok = term1Tok;
varId = var1Tok->varId();
if (!varId) {
continue;
}
varFirst1 = true;
firstConstant = term1Tok->strAt(2);
} else if (Token::Match(term1Tok, "%num% %any% %var%")) {
var1Tok = term1Tok->tokAt(2);
varId = var1Tok->varId();
if (!varId) {
continue;
}
varFirst1 = false;
firstConstant = term1Tok->str();
} else {
continue;
}
if (Token::Match(term2Tok, "%var% %any% %num%")) {
var2Tok = term2Tok;
varFirst2 = true;
secondConstant = term2Tok->strAt(2);
} else if (Token::Match(term2Tok, "%num% %any% %var%")) {
var2Tok = term2Tok->tokAt(2);
varFirst2 = false;
secondConstant = term2Tok->str();
} else {
continue;
}
if (varId != var2Tok->varId() || firstConstant.empty() || secondConstant.empty()) {
continue;
}
enum LogicError { AlwaysFalse, AlwaysTrue, FirstTrue, FirstFalse, SecondTrue, SecondFalse };
static const struct LinkedConditions {
const char *before;
Condition c1;
const char *op2TokStr;
Condition c2;
const char *after;
Relation relation;
LogicError error;
} conditions[] = {
{ "!!&&", { NA, "!=" }, "%oror%", { NA, "!=" }, "!!&&", NotEqual, AlwaysTrue }, // (x != 1) || (x != 3) <- always true
{ 0, { NA, "==" }, "&&", { NA, "==" }, 0, NotEqual, AlwaysFalse }, // (x == 1) && (x == 3) <- always false
{ "!!&&", { First, ">" }, "%oror%", { First, "<" }, "!!&&", Less, AlwaysTrue }, // (x > 3) || (x < 10) <- always true
{ "!!&&", { First, ">=" }, "%oror%", { First, "<|<=" }, "!!&&", LessEqual, AlwaysTrue }, // (x >= 3) || (x < 10) <- always true
{ "!!&&", { First, ">" }, "%oror%", { First, "<=" }, "!!&&", LessEqual, AlwaysTrue }, // (x > 3) || (x <= 10) <- always true
{ 0, { First, "<" }, "&&", { First, ">" }, 0, LessEqual, AlwaysFalse }, // (x < 1) && (x > 3) <- always false
{ 0, { First, "<=" }, "&&", { First, ">|>=" }, 0, Less, AlwaysFalse }, // (x <= 1) && (x > 3) <- always false
{ 0, { First, "<" }, "&&", { First, ">=" }, 0, Less, AlwaysFalse }, // (x < 1) && (x >= 3) <- always false
{ 0, { First, ">" }, "&&", { NA, "==" }, 0, MoreEqual, AlwaysFalse }, // (x > 5) && (x == 1) <- always false
{ 0, { First, "<" }, "&&", { NA, "==" }, 0, LessEqual, AlwaysFalse }, // (x < 1) && (x == 3) <- always false
{ 0, { First, ">=" }, "&&", { NA, "==" }, 0, More, AlwaysFalse }, // (x >= 5) && (x == 1) <- always false
{ 0, { First, "<=" }, "&&", { NA, "==" }, 0, Less, AlwaysFalse }, // (x <= 1) && (x == 3) <- always false
{ "!!&&", { NA, "==" }, "%oror%", { First, ">" }, "!!&&", More, SecondTrue }, // (x == 4) || (x > 3) <- second expression always true
{ "!!&&", { NA, "==" }, "%oror%", { First, "<" }, "!!&&", Less, SecondTrue }, // (x == 4) || (x < 5) <- second expression always true
{ "!!&&", { NA, "==" }, "%oror%", { First, ">=" }, "!!&&", MoreEqual, SecondTrue }, // (x == 4) || (x >= 3) <- second expression always true
{ "!!&&", { NA, "==" }, "%oror%", { First, "<=" }, "!!&&", LessEqual, SecondTrue }, // (x == 4) || (x <= 5) <- second expression always true
{ "!!&&", { First, ">" }, "%oror%", { NA, "!=" }, "!!&&", MoreEqual, SecondTrue }, // (x > 5) || (x != 1) <- second expression always true
{ "!!&&", { First, "<" }, "%oror%", { NA, "!=" }, "!!&&", LessEqual, SecondTrue }, // (x < 1) || (x != 3) <- second expression always true
{ "!!&&", { First, ">=" }, "%oror%", { NA, "!=" }, "!!&&", More, SecondTrue }, // (x >= 5) || (x != 1) <- second expression always true
{ "!!&&", { First, "<=" }, "%oror%", { NA, "!=" }, "!!&&", Less, SecondTrue }, // (x <= 1) || (x != 3) <- second expression always true
{ 0, { First, ">" }, "&&", { NA, "!=" }, 0, MoreEqual, SecondTrue }, // (x > 5) && (x != 1) <- second expression always true
{ 0, { First, "<" }, "&&", { NA, "!=" }, 0, LessEqual, SecondTrue }, // (x < 1) && (x != 3) <- second expression always true
{ 0, { First, ">=" }, "&&", { NA, "!=" }, 0, More, SecondTrue }, // (x >= 5) && (x != 1) <- second expression always true
{ 0, { First, "<=" }, "&&", { NA, "!=" }, 0, Less, SecondTrue }, // (x <= 1) && (x != 3) <- second expression always true
{ "!!&&", { First, ">|>=" }, "%oror%", { First, ">|>=" }, "!!&&", LessEqual, SecondTrue }, // (x > 4) || (x > 5) <- second expression always true
{ "!!&&", { First, "<|<=" }, "%oror%", { First, "<|<=" }, "!!&&", MoreEqual, SecondTrue }, // (x < 5) || (x < 4) <- second expression always true
{ 0, { First, ">|>=" }, "&&", { First, ">|>=" }, 0, MoreEqual, SecondTrue }, // (x > 4) && (x > 5) <- second expression always true
{ 0, { First, "<|<=" }, "&&", { First, "<|<=" }, 0, MoreEqual, SecondTrue }, // (x < 5) && (x < 4) <- second expression always true
{ 0, { NA, "==" }, "&&", { NA, "!=" }, 0, NotEqual, SecondTrue }, // (x == 3) && (x != 4) <- second expression always true
{ "!!&&", { NA, "==" }, "%oror%", { NA, "!=" }, "!!&&", NotEqual, SecondTrue }, // (x == 3) || (x != 4) <- second expression always true
{ 0, { NA, "!=" }, "&&", { NA, "==" }, 0, Equal, AlwaysFalse }, // (x != 3) && (x == 3) <- expression always false
{ "!!&&", { NA, "!=" }, "%oror%", { NA, "==" }, "!!&&", Equal, AlwaysTrue }, // (x != 3) || (x == 3) <- expression always true
};
for (unsigned int i = 0; i < (sizeof(conditions) / sizeof(conditions[0])); i++) {
if (!Token::Match(op2Tok, conditions[i].op2TokStr))
continue;
if (conditions[i].before != 0 && !Token::Match(tok->previous(), conditions[i].before))
continue;
if (conditions[i].after != 0 && !Token::Match(nextTok, conditions[i].after))
continue;
if (tok->previous()->isArithmeticalOp() || nextTok->isArithmeticalOp())
continue;
std::string cond1str = var1Tok->str() + " " + (varFirst1?op1Tok->str():invertOperatorForOperandSwap(op1Tok->str())) + " " + firstConstant;
std::string cond2str = var2Tok->str() + " " + (varFirst2?op3Tok->str():invertOperatorForOperandSwap(op3Tok->str())) + " " + secondConstant;
// cond1 op cond2
bool error = analyzeLogicOperatorCondition(conditions[i].c1, conditions[i].c2, false, false,
varFirst1, varFirst2, firstConstant, secondConstant,
op1Tok, op3Tok,
conditions[i].relation);
// inv(cond1) op cond2 // invert first condition
if (!error && conditions[i].c1.position != NA)
error = analyzeLogicOperatorCondition(conditions[i].c1, conditions[i].c2, true, false,
!varFirst1, varFirst2, firstConstant, secondConstant,
op1Tok, op3Tok,
conditions[i].relation);
// cond1 op inv(cond2) // invert second condition
if (!error && conditions[i].c2.position != NA)
error = analyzeLogicOperatorCondition(conditions[i].c1, conditions[i].c2, false, true,
varFirst1, !varFirst2, firstConstant, secondConstant,
op1Tok, op3Tok,
conditions[i].relation);
// inv(cond1) op inv(cond2) // invert both conditions
if (!error && conditions[i].c1.position != NA && conditions[i].c2.position != NA)
error = analyzeLogicOperatorCondition(conditions[i].c1, conditions[i].c2, true, true,
!varFirst1, !varFirst2, firstConstant, secondConstant,
op1Tok, op3Tok,
conditions[i].relation);
if (!error)
std::swap(cond1str, cond2str);
// cond2 op cond1 // swap conditions
if (!error)
error = analyzeLogicOperatorCondition(conditions[i].c1, conditions[i].c2, false, false,
varFirst2, varFirst1, secondConstant, firstConstant,
op3Tok, op1Tok,
conditions[i].relation);
// cond2 op inv(cond1) // swap conditions; invert first condition
if (!error && conditions[i].c1.position != NA)
error = analyzeLogicOperatorCondition(conditions[i].c1, conditions[i].c2, true, false,
!varFirst2, varFirst1, secondConstant, firstConstant,
op3Tok, op1Tok,
conditions[i].relation);
// inv(cond2) op cond1 // swap conditions; invert second condition
if (!error && conditions[i].c2.position != NA)
error = analyzeLogicOperatorCondition(conditions[i].c1, conditions[i].c2, false, true,
varFirst2, !varFirst1, secondConstant, firstConstant,
op3Tok, op1Tok,
conditions[i].relation);
// inv(cond2) op inv(cond1) // swap conditions; invert both conditions
if (!error && conditions[i].c1.position != NA && conditions[i].c2.position != NA)
error = analyzeLogicOperatorCondition(conditions[i].c1, conditions[i].c2, true, true,
!varFirst2, !varFirst1, secondConstant, firstConstant,
op3Tok, op1Tok,
conditions[i].relation);
if (error) {
if (conditions[i].error == AlwaysFalse || conditions[i].error == AlwaysTrue) {
const std::string text = cond1str + " " + op2Tok->str() + " " + cond2str;
incorrectLogicOperatorError(term1Tok, text, conditions[i].error == AlwaysTrue);
} else {
const std::string text = "If " + cond1str + ", the comparison " + cond2str +
" is always " + ((conditions[i].error == SecondTrue || conditions[i].error == AlwaysTrue) ? "true" : "false") + ".";
redundantConditionError(term1Tok, text);
}
break;
}
}
}
}
}
void CheckOther::incorrectLogicOperatorError(const Token *tok, const std::string &condition, bool always)
{
if (always)
reportError(tok, Severity::warning, "incorrectLogicOperator",
"Logical disjunction always evaluates to true: " + condition + ".\n"
"Are these conditions necessary? Did you intend to use && instead? Are the numbers correct? Are you comparing the correct variables?");
else
reportError(tok, Severity::warning, "incorrectLogicOperator",
"Logical conjunction always evaluates to false: " + condition + ".\n"
"Are these conditions necessary? Did you intend to use || instead? Are the numbers correct? Are you comparing the correct variables?");
}
void CheckOther::redundantConditionError(const Token *tok, const std::string &text)
{
reportError(tok, Severity::style, "redundantCondition", "Redundant condition: " + text);
}
//---------------------------------------------------------------------------
// strtol(str, 0, radix) <- radix must be 0 or 2-36
//---------------------------------------------------------------------------
void CheckOther::invalidFunctionUsage()
{
// strtol and strtoul..
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (!Token::Match(tok, "strtol|strtoul ("))
continue;
tok = tok->tokAt(2);
// Locate the third parameter of the function call..
for (int i = 0; i < 2 && tok; i++)
tok = tok->nextArgument();
if (Token::Match(tok, "%num% )")) {
const MathLib::bigint radix = MathLib::toLongNumber(tok->str());
if (!(radix == 0 || (radix >= 2 && radix <= 36))) {
dangerousUsageStrtolError(tok);
}
} else
break;
}
// sprintf|snprintf overlapping data
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
// Get variable id of target buffer..
unsigned int varid = 0;
if (Token::Match(tok, "sprintf|snprintf ( %var% ,"))
varid = tok->tokAt(2)->varId();
else if (Token::Match(tok, "sprintf|snprintf ( %var% . %var% ,"))
varid = tok->tokAt(4)->varId();
if (varid == 0)
continue;
// goto ","
const Token *tok2 = tok->tokAt(3);
while (tok2->str() != ",")
tok2 = tok2->next();
tok2 = tok2->next(); // Jump behind ","
if (tok->str() == "snprintf") { // Jump over second parameter for snprintf
tok2 = tok2->nextArgument();
if (!tok2)
continue;
}
// is any source buffer overlapping the target buffer?
do {
if (Token::Match(tok2, "%varid% [,)]", varid)) {
sprintfOverlappingDataError(tok2->next(), tok2->next()->str());
break;
}
} while (NULL != (tok2 = tok2->nextArgument()));
}
}
void CheckOther::dangerousUsageStrtolError(const Token *tok)
{
reportError(tok, Severity::error, "dangerousUsageStrtol", "Invalid radix in call to strtol or strtoul. Must be 0 or 2-36");
}
void CheckOther::sprintfOverlappingDataError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::error, "sprintfOverlappingData",
"Undefined behavior: variable is used as parameter and destination in s[n]printf().\n"
"The variable '" + varname + "' is used both as a parameter and as a destination in "
"s[n]printf(). The origin and destination buffers overlap. Quote from glibc (C-library) "
"documentation (http://www.gnu.org/software/libc/manual/html_mono/libc.html#Formatted-Output-Functions): "
"'If copying takes place between objects that overlap as a result of a call "
"to sprintf() or snprintf(), the results are undefined.'");
}
//---------------------------------------------------------------------------
// if (!x==3) <- Probably meant to be "x!=3"
//---------------------------------------------------------------------------
static bool isBool(const Variable* var)
{
return(var && var->typeEndToken()->str() == "bool");
}
static bool isNonBoolStdType(const Variable* var)
{
return(var && var->typeEndToken()->isStandardType() && var->typeEndToken()->str() != "bool");
}
void CheckOther::checkComparisonOfBoolWithInt()
{
if (!_settings->isEnabled("style"))
return;
const SymbolDatabase* const symbolDatabase = _tokenizer->getSymbolDatabase();
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (tok->next() && tok->next()->type() == Token::eComparisonOp && (!tok->previous() || !tok->previous()->isArithmeticalOp()) && (!tok->tokAt(3) || !tok->tokAt(3)->isArithmeticalOp())) {
const Token* const right = tok->tokAt(2);
if ((tok->varId() && right->isNumber()) || (tok->isNumber() && right->varId())) { // Comparing variable with number
const Token* varTok = tok;
const Token* numTok = right;
if (tok->isNumber() && right->varId()) // num with var
std::swap(varTok, numTok);
if (isBool(symbolDatabase->getVariableFromVarId(varTok->varId())) && // Variable has to be a boolean
((tok->strAt(1) != "==" && tok->strAt(1) != "!=") ||
(MathLib::toLongNumber(numTok->str()) != 0 && MathLib::toLongNumber(numTok->str()) != 1))) { // == 0 and != 0 are allowed, for C also == 1 and != 1
comparisonOfBoolWithIntError(varTok, numTok->str(), tok->strAt(1) == "==" || tok->strAt(1) == "!=");
}
} else if (tok->isBoolean() && right->varId()) { // Comparing boolean constant with variable
if (isNonBoolStdType(symbolDatabase->getVariableFromVarId(right->varId()))) { // Variable has to be of non-boolean standard type
comparisonOfBoolWithIntError(right, tok->str(), false);
} else if (tok->strAt(1) != "==" && tok->strAt(1) != "!=") {
comparisonOfBoolWithInvalidComparator(right, tok->str());
}
} else if (tok->varId() && right->isBoolean()) { // Comparing variable with boolean constant
if (isNonBoolStdType(symbolDatabase->getVariableFromVarId(tok->varId()))) { // Variable has to be of non-boolean standard type
comparisonOfBoolWithIntError(tok, right->str(), false);
} else if (tok->strAt(1) != "==" && tok->strAt(1) != "!=") {
comparisonOfBoolWithInvalidComparator(right, tok->str());
}
} else if (tok->isNumber() && right->isBoolean()) { // number constant with boolean constant
comparisonOfBoolWithIntError(tok, right->str(), false);
} else if (tok->isBoolean() && right->isNumber()) { // number constant with boolean constant
comparisonOfBoolWithIntError(tok, tok->str(), false);
} else if (tok->varId() && right->varId()) { // Comparing two variables, one of them boolean, one of them integer
const Variable* var1 = symbolDatabase->getVariableFromVarId(right->varId());
const Variable* var2 = symbolDatabase->getVariableFromVarId(tok->varId());
if (isBool(var1) && isNonBoolStdType(var2)) // Comparing boolean with non-bool standard type
comparisonOfBoolWithIntError(tok, var1->name(), false);
else if (isNonBoolStdType(var1) && isBool(var2)) // Comparing non-bool standard type with boolean
comparisonOfBoolWithIntError(tok, var2->name(), false);
}
}
}
}
void CheckOther::comparisonOfBoolWithIntError(const Token *tok, const std::string &expression, bool n0o1)
{
if (n0o1)
reportError(tok, Severity::warning, "comparisonOfBoolWithInt",
"Comparison of a boolean with an integer that is neither 1 nor 0\n"
"The expression \"" + expression + "\" is of type 'bool' "
"and it is compared against a integer value that is "
"neither 1 nor 0.");
else
reportError(tok, Severity::warning, "comparisonOfBoolWithInt",
"Comparison of a boolean with an integer\n"
"The expression \"" + expression + "\" is of type 'bool' "
"and it is compared against a integer value.");
}
void CheckOther::comparisonOfBoolWithInvalidComparator(const Token *tok, const std::string &expression)
{
reportError(tok, Severity::warning, "comparisonOfBoolWithInvalidComparator",
"Comparison of a boolean value using relational (<, >, <= or >=) operator.\n"
"The expression \"" + expression + "\" is of type 'bool' "
"and result is of type 'bool'. Comparing 'bool' value using relational (<, >, <= or >=)"
" operator could cause unexpected results.");
}
//---------------------------------------------------------------------------
// Find consecutive return, break, continue, goto or throw statements. e.g.:
// break; break;
// Detect dead code, that follows such a statement. e.g.:
// return(0); foo();
//---------------------------------------------------------------------------
void CheckOther::checkUnreachableCode()
{
if (!_settings->isEnabled("style"))
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
const Token* secondBreak = 0;
const Token* labelName = 0;
if (tok->str() == "(")
tok = tok->link();
else if (Token::Match(tok, "break|continue ;"))
secondBreak = tok->tokAt(2);
else if (Token::Match(tok, "[;{}:] return|throw")) {
tok = tok->next(); // tok should point to return or throw
for (const Token *tok2 = tok->next(); tok2; tok2 = tok2->next())
if (tok2->str() == ";") {
secondBreak = tok2->next();
break;
}
} else if (Token::Match(tok, "goto %any% ;")) {
secondBreak = tok->tokAt(3);
labelName = tok->next();
}
// Statements follow directly, no line between them. (#3383)
// TODO: Try to find a better way to avoid false positives due to preprocessor configurations.
bool inconclusive = secondBreak && (secondBreak->linenr()-1 > secondBreak->previous()->linenr());
if (secondBreak && (_settings->inconclusive || !inconclusive)) {
if (Token::Match(secondBreak, "continue|goto|throw") ||
(secondBreak->str() == "return" && (tok->str() == "return" || secondBreak->strAt(1) == ";"))) { // return with value after statements like throw can be necessary to make a function compile
duplicateBreakError(secondBreak, inconclusive);
tok = Token::findmatch(secondBreak, "[}:]");
} else if (secondBreak->str() == "break") { // break inside switch as second break statement should not issue a warning
if (tok->str() == "break") // If the previous was a break, too: Issue warning
duplicateBreakError(secondBreak, inconclusive);
else {
if (tok->scope()->type != Scope::eSwitch) // Check, if the enclosing scope is a switch
duplicateBreakError(secondBreak, inconclusive);
}
tok = Token::findmatch(secondBreak, "[}:]");
} else if (!Token::Match(secondBreak, "return|}|case|default") && secondBreak->strAt(1) != ":") { // TODO: No bailout for unconditional scopes
// If the goto label is followed by a loop construct in which the label is defined it's quite likely
// that the goto jump was intended to skip some code on the first loop iteration.
bool labelInFollowingLoop = false;
if (labelName && Token::Match(secondBreak, "while|do|for")) {
const Token *scope = Token::findsimplematch(secondBreak, "{");
if (scope) {
for (const Token *tokIter = scope; tokIter != scope->link() && tokIter; tokIter = tokIter->next()) {
if (Token::Match(tokIter, "[;{}] %any% :") && labelName->str() == tokIter->strAt(1)) {
labelInFollowingLoop = true;
break;
}
}
}
}
if (!labelInFollowingLoop)
unreachableCodeError(secondBreak, inconclusive);
tok = Token::findmatch(secondBreak, "[}:]");
} else
tok = secondBreak;
if (!tok)
break;
}
}
}
void CheckOther::duplicateBreakError(const Token *tok, bool inconclusive)
{
reportError(tok, Severity::style, "duplicateBreak",
"Consecutive return, break, continue, goto or throw statements are unnecessary.\n"
"The second of the two statements can never be executed, and so should be removed.", inconclusive);
}
void CheckOther::unreachableCodeError(const Token *tok, bool inconclusive)
{
reportError(tok, Severity::style, "unreachableCode",
"Statements following return, break, continue, goto or throw will never be executed.", inconclusive);
}
//---------------------------------------------------------------------------
// Check for unsigned divisions
//---------------------------------------------------------------------------
static bool isUnsigned(const Variable* var)
{
return(var && var->typeStartToken()->isUnsigned() && !var->isPointer() && !var->isArray());
}
static bool isSigned(const Variable* var)
{
return(var && !var->typeStartToken()->isUnsigned() && Token::Match(var->typeEndToken(), "int|char|short|long") && !var->isPointer() && !var->isArray());
}
void CheckOther::checkUnsignedDivision()
{
const SymbolDatabase* symbolDatabase = _tokenizer->getSymbolDatabase();
bool style = _settings->isEnabled("style");
const Token* ifTok = 0;
// Check for "ivar / uvar" and "uvar / ivar"
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::Match(tok, "[).]")) // Don't check members or casted variables
continue;
if (Token::Match(tok->next(), "%var% / %num%")) {
if (tok->strAt(3)[0] == '-' && isUnsigned(symbolDatabase->getVariableFromVarId(tok->next()->varId()))) {
udivError(tok->next(), false);
}
} else if (Token::Match(tok->next(), "%num% / %var%")) {
if (tok->strAt(1)[0] == '-' && isUnsigned(symbolDatabase->getVariableFromVarId(tok->tokAt(3)->varId()))) {
udivError(tok->next(), false);
}
} else if (Token::Match(tok->next(), "%var% / %var%") && _settings->inconclusive && style && !ifTok) {
const Variable* var1 = symbolDatabase->getVariableFromVarId(tok->next()->varId());
const Variable* var2 = symbolDatabase->getVariableFromVarId(tok->tokAt(3)->varId());
if ((isUnsigned(var1) && isSigned(var2)) || (isUnsigned(var2) && isSigned(var1))) {
udivError(tok->next(), true);
}
} else if (!ifTok && Token::simpleMatch(tok, "if ("))
ifTok = tok->next()->link()->next()->link();
else if (ifTok == tok)
ifTok = 0;
}
}
void CheckOther::udivError(const Token *tok, bool inconclusive)
{
if (inconclusive)
reportError(tok, Severity::warning, "udivError", "Division with signed and unsigned operators. The result might be wrong.", true);
else
reportError(tok, Severity::error, "udivError", "Unsigned division. The result will be wrong.");
}
//---------------------------------------------------------------------------
// memset(p, y, 0 /* bytes to fill */) <- 2nd and 3rd arguments inverted
//---------------------------------------------------------------------------
void CheckOther::checkMemsetZeroBytes()
{
if (!_settings->isEnabled("style"))
return;
for (const Token* tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::simpleMatch(tok, "memset (")) {
const Token* lastParamTok = tok->next()->link()->previous();
if (lastParamTok->str() == "0")
memsetZeroBytesError(tok, tok->strAt(2));
}
}
}
void CheckOther::memsetZeroBytesError(const Token *tok, const std::string &varname)
{
const std::string summary("memset() called to fill 0 bytes of \'" + varname + "\'");
const std::string verbose(summary + ". Second and third arguments might be inverted.");
reportError(tok, Severity::warning, "memsetZeroBytes", summary + "\n" + verbose);
}
//---------------------------------------------------------------------------
// Check scope of variables..
//---------------------------------------------------------------------------
void CheckOther::checkVariableScope()
{
if (!_settings->isEnabled("style"))
return;
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
for (unsigned int i = 1; i < symbolDatabase->getVariableListSize(); i++) {
const Variable* var = symbolDatabase->getVariableFromVarId(i);
if (!var || !var->isLocal() || (!var->isPointer() && !var->typeStartToken()->isStandardType() && !var->typeStartToken()->next()->isStandardType()))
continue;
bool forHead = false; // Don't check variables declared in header of a for loop
for (const Token* tok = var->typeStartToken(); tok; tok = tok->previous()) {
if (tok->str() == "(") {
forHead = true;
break;
} else if (tok->str() == "{" || tok->str() == ";" || tok->str() == "}")
break;
}
if (forHead)
continue;
const Token* tok = var->nameToken()->next();
if (Token::Match(tok, "; %varid% = %any% ;", var->varId())) {
tok = tok->tokAt(3);
if (!tok->isNumber() && tok->type() != Token::eString && tok->type() != Token::eChar && !tok->isBoolean())
continue;
} else if ((tok->str() == "=" || tok->str() == "(") &&
((!tok->next()->isNumber() && tok->next()->type() != Token::eString && tok->next()->type() != Token::eChar && !tok->next()->isBoolean()) || tok->strAt(2) != ";"))
continue;
lookupVar(tok, var);
}
}
void CheckOther::lookupVar(const Token *tok, const Variable* var)
{
// Skip the variable declaration..
while (tok && tok->str() != ";")
tok = tok->next();
// Check if the variable is used in this indentlevel..
bool used1 = false; // used in one sub-scope -> reducable
bool used2 = false; // used in more sub-scopes -> not reducable
unsigned int indentlevel = 0;
int parlevel = 0;
bool for_or_while = false; // is sub-scope a "for/while/etc". anything that is not "if"
while (tok) {
if (tok->str() == "{") {
if (tok->strAt(-1) == "=") {
if (Token::findmatch(tok, "%varid%", tok->link(), var->varId())) {
return;
}
tok = tok->link();
} else
++indentlevel;
}
else if (tok->str() == "}") {
if (indentlevel == 0)
break;
--indentlevel;
if (indentlevel == 0) {
if (for_or_while && used2)
return;
used2 |= used1;
used1 = false;
}
}
else if (tok->str() == "(") {
++parlevel;
}
else if (tok->str() == ")") {
--parlevel;
}
// Bail out if references are used
else if (Token::Match(tok, "& %varid%", var->varId())) {
return;
}
else if (tok->varId() == var->varId()) {
if (indentlevel == 0)
return;
if (tok->strAt(-1) == "=" && (var->isArray() || var->isPointer())) // Create a copy of array/pointer. Bailout, because the memory it points to might be necessary in outer scope
return;
used1 = true;
if (for_or_while && tok->strAt(1) != "=")
used2 = true;
if (used1 && used2)
return;
}
else if (indentlevel == 0) {
// %unknown% ( %any% ) {
// If %unknown% is anything except if, we assume
// that it is a for or while loop or a macro hiding either one
if (tok->strAt(1) == "(" &&
Token::simpleMatch(tok->next()->link(), ") {")) {
if (tok->str() != "if")
for_or_while = true;
}
else if (Token::simpleMatch(tok, "do {"))
for_or_while = true;
// possible unexpanded macro hiding for/while..
else if (tok->str() != "else" && Token::Match(tok->previous(), "[;{}] %type% {")) {
for_or_while = true;
}
if (parlevel == 0 && (tok->str() == ";"))
for_or_while = false;
}
tok = tok->next();
}
// Warning if this variable:
// * not used in this indentlevel
// * used in lower indentlevel
if (used1 || used2)
variableScopeError(var->nameToken(), var->name());
}
void CheckOther::variableScopeError(const Token *tok, const std::string &varname)
{
reportError(tok,
Severity::style,
"variableScope",
"The scope of the variable '" + varname + "' can be reduced\n"
"The scope of the variable '" + varname + "' can be reduced. Warning: It can be unsafe "
"to fix this message. Be careful. Especially when there are inner loops. Here is an "
"example where cppcheck will write that the scope for 'i' can be reduced:\n"
"void f(int x)\n"
"{\n"
" int i = 0;\n"
" if (x) {\n"
" // it's safe to move 'int i = 0' here\n"
" for (int n = 0; n < 10; ++n) {\n"
" // it is possible but not safe to move 'int i = 0' here\n"
" do_something(&i);\n"
" }\n"
" }\n"
"}\n"
"When you see this message it is always safe to reduce the variable scope 1 level.");
}
//---------------------------------------------------------------------------
// Check for constant function parameters
//---------------------------------------------------------------------------
void CheckOther::checkConstantFunctionParameter()
{
if (!_settings->isEnabled("performance"))
return;
const SymbolDatabase * const symbolDatabase = _tokenizer->getSymbolDatabase();
for (unsigned int i = 1; i < symbolDatabase->getVariableListSize(); i++) {
const Variable* var = symbolDatabase->getVariableFromVarId(i);
if (!var || !var->isArgument() || !var->isClass() || !var->isConst() || var->isPointer() || var->isArray() || var->isReference())
continue;
const Token* const tok = var->typeStartToken();
// TODO: False negatives. This pattern only checks for string.
// Investigate if there are other classes in the std
// namespace and add them to the pattern. There are
// streams for example (however it seems strange with
// const stream parameter).
if (Token::Match(tok, "std :: string|wstring")) {
passedByValueError(tok, var->name());
} else if (Token::Match(tok, "std :: %type% <") && !Token::Match(tok->linkAt(3), "> ::")) {
passedByValueError(tok, var->name());
} else if (var->type() || symbolDatabase->isClassOrStruct(tok->str())) { // Check if type is a struct or class.
passedByValueError(tok, var->name());
}
}
}
void CheckOther::passedByValueError(const Token *tok, const std::string &parname)
{
reportError(tok, Severity::performance, "passedByValue",
"Function parameter '" + parname + "' should be passed by reference.\n"
"Parameter '" + parname + "' is passed as a value. It could be passed "
"as a (const) reference which is usually faster and recommended in C++.");
}
//---------------------------------------------------------------------------
// Check usage of char variables..
//---------------------------------------------------------------------------
static bool isChar(const Variable* var)
{
return(var && !var->isPointer() && !var->isArray() && var->typeStartToken()->str() == "char");
}
static bool isSignedChar(const Variable* var)
{
return(isChar(var) && !var->typeStartToken()->isUnsigned());
}
void CheckOther::checkCharVariable()
{
if (!_settings->isEnabled("style"))
return;
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if ((tok->str() != ".") && Token::Match(tok->next(), "%var% [ %var% ]")) {
const Variable* arrayvar = symbolDatabase->getVariableFromVarId(tok->next()->varId());
const Variable* indexvar = symbolDatabase->getVariableFromVarId(tok->tokAt(3)->varId());
const MathLib::bigint arraysize = (arrayvar && arrayvar->isArray()) ? arrayvar->dimension(0U) : 0;
if (isSignedChar(indexvar) && arraysize > 0x80)
charArrayIndexError(tok->next());
}
else if (Token::Match(tok, "[;{}] %var% = %any% [&^|] %any% ;")) {
// is a char variable used in the calculation?
if (!isSignedChar(symbolDatabase->getVariableFromVarId(tok->tokAt(3)->varId())) &&
!isSignedChar(symbolDatabase->getVariableFromVarId(tok->tokAt(5)->varId())))
continue;
// it's ok with a bitwise and where the other operand is 0xff or less..
if (tok->strAt(4) == "&") {
if (tok->tokAt(3)->isNumber() && MathLib::isGreater("0x100", tok->strAt(3)))
continue;
if (tok->tokAt(5)->isNumber() && MathLib::isGreater("0x100", tok->strAt(5)))
continue;
}
// is the result stored in a short|int|long?
const Variable *var = symbolDatabase->getVariableFromVarId(tok->next()->varId());
if (var && Token::Match(var->typeStartToken(), "short|int|long") && !var->isPointer() && !var->isArray())
charBitOpError(tok->tokAt(4)); // This is an error..
}
else if (Token::Match(tok, "[;{}] %var% = %any% [&^|] ( * %var% ) ;")) {
const Variable* var = symbolDatabase->getVariableFromVarId(tok->tokAt(7)->varId());
if (!var || !var->isPointer() || var->typeStartToken()->str() != "char" || var->typeStartToken()->isUnsigned())
continue;
// it's ok with a bitwise and where the other operand is 0xff or less..
if (tok->strAt(4) == "&" && tok->tokAt(3)->isNumber() && MathLib::isGreater("0x100", tok->strAt(3)))
continue;
// is the result stored in a short|int|long?
var = symbolDatabase->getVariableFromVarId(tok->next()->varId());
if (var && Token::Match(var->typeStartToken(), "short|int|long") && !var->isPointer() && !var->isArray())
charBitOpError(tok->tokAt(4)); // This is an error..
}
}
}
void CheckOther::charArrayIndexError(const Token *tok)
{
reportError(tok,
Severity::warning,
"charArrayIndex",
"Using char type as array index\n"
"Using signed char type as array index. If the value "
"can be greater than 127 there will be a buffer overflow "
"(because of sign extension).");
}
void CheckOther::charBitOpError(const Token *tok)
{
reportError(tok,
Severity::warning,
"charBitOp",
"When using char variables in bit operations, sign extension can generate unexpected results.\n"
"When using char variables in bit operations, sign extension can generate unexpected results. For example:\n"
" char c = 0x80;\n"
" int i = 0 | c;\n"
" if (i & 0x8000)\n"
" printf(\"not expected\");\n"
"The 'not expected' will be printed on the screen.");
}
//---------------------------------------------------------------------------
// Incomplete statement..
//---------------------------------------------------------------------------
void CheckOther::checkIncompleteStatement()
{
if (!_settings->isEnabled("style"))
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (tok->str() == "(") {
tok = tok->link();
if (Token::simpleMatch(tok, ") {") && Token::simpleMatch(tok->next()->link(), "} ;"))
tok = tok->next()->link();
}
else if (Token::simpleMatch(tok, "= {"))
tok = tok->next()->link();
else if (tok->str() == "{" && Token::Match(tok->tokAt(-2), "%type% %var%"))
tok = tok->link();
else if (Token::Match(tok, "[;{}] %str%") || Token::Match(tok, "[;{}] %num%")) {
// No warning if numeric constant is followed by a "." or ","
if (Token::Match(tok->next(), "%num% [,.]"))
continue;
// bailout if there is a "? :" in this statement
bool bailout = false;
for (const Token *tok2 = tok->tokAt(2); tok2; tok2 = tok2->next()) {
if (tok2->str() == "?")
bailout = true;
else if (tok2->str() == ";")
break;
}
if (bailout)
continue;
constStatementError(tok->next(), tok->next()->isNumber() ? "numeric" : "string");
}
}
}
void CheckOther::constStatementError(const Token *tok, const std::string &type)
{
reportError(tok, Severity::warning, "constStatement", "Redundant code: Found a statement that begins with " + type + " constant");
}
//---------------------------------------------------------------------------
// str plus char
//---------------------------------------------------------------------------
void CheckOther::strPlusChar()
{
// Don't use this check for Java and C# programs..
if (_tokenizer->isJavaOrCSharp()) {
return;
}
const SymbolDatabase* symbolDatabase = _tokenizer->getSymbolDatabase();
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::Match(tok, "[=(] %str% + %any%")) {
// char constant..
if (tok->tokAt(3)->type() == Token::eChar)
strPlusCharError(tok->next());
// char variable..
unsigned int varid = tok->tokAt(3)->varId();
if (isChar(symbolDatabase->getVariableFromVarId(varid)))
strPlusCharError(tok->next());
}
}
}
void CheckOther::strPlusCharError(const Token *tok)
{
reportError(tok, Severity::error, "strPlusChar", "Unusual pointer arithmetic");
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
void CheckOther::checkZeroDivision()
{
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::Match(tok, "[/%] %num%") &&
MathLib::isInt(tok->next()->str()) &&
MathLib::toLongNumber(tok->next()->str()) == 0L) {
zerodivError(tok);
} else if (Token::Match(tok, "div|ldiv|lldiv|imaxdiv ( %num% , %num% )") &&
MathLib::isInt(tok->strAt(4)) &&
MathLib::toLongNumber(tok->strAt(4)) == 0L) {
zerodivError(tok);
}
}
}
void CheckOther::zerodivError(const Token *tok)
{
reportError(tok, Severity::error, "zerodiv", "Division by zero");
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
void CheckOther::checkMathFunctions()
{
const SymbolDatabase *db = _tokenizer->getSymbolDatabase();
std::list<Scope>::const_iterator scope;
for (scope = db->scopeList.begin(); scope != db->scopeList.end(); ++scope) {
if (scope->type != Scope::eFunction)
continue;
for (const Token *tok = scope->classStart; tok && tok != scope->classEnd; tok = tok->next()) {
if (tok->varId())
continue;
if (Token::Match(tok, "log|log10 ( %num% )")) {
bool isNegative = MathLib::isNegative(tok->strAt(2));
bool isInt = MathLib::isInt(tok->strAt(2));
bool isFloat = MathLib::isFloat(tok->strAt(2));
if (isNegative && isInt && MathLib::toLongNumber(tok->strAt(2)) <= 0) {
mathfunctionCallError(tok); // case log(-2)
} else if (isNegative && isFloat && MathLib::toDoubleNumber(tok->strAt(2)) <= 0.) {
mathfunctionCallError(tok); // case log(-2.0)
} else if (!isNegative && isFloat && MathLib::toDoubleNumber(tok->strAt(2)) <= 0.) {
mathfunctionCallError(tok); // case log(0.0)
} else if (!isNegative && isInt && MathLib::toLongNumber(tok->strAt(2)) <= 0) {
mathfunctionCallError(tok); // case log(0)
}
}
// acos( x ), asin( x ) where x is defined for intervall [-1,+1], but not beyound
else if (Token::Match(tok, "acos|asin ( %num% )") &&
std::fabs(MathLib::toDoubleNumber(tok->strAt(2))) > 1.0) {
mathfunctionCallError(tok);
}
// sqrt( x ): if x is negative the result is undefined
else if (Token::Match(tok, "sqrt|sqrtf|sqrtl ( %num% )") &&
MathLib::isNegative(tok->strAt(2))) {
mathfunctionCallError(tok);
}
// atan2 ( x , y): x and y can not be zero, because this is mathematically not defined
else if (Token::Match(tok, "atan2 ( %num% , %num% )") &&
MathLib::isNullValue(tok->strAt(2)) &&
MathLib::isNullValue(tok->strAt(4))) {
mathfunctionCallError(tok, 2);
}
// fmod ( x , y) If y is zero, then either a range error will occur or the function will return zero (implementation-defined).
else if (Token::Match(tok, "fmod ( %any%")) {
const Token* nextArg = tok->tokAt(2)->nextArgument();
if (nextArg && nextArg->isNumber() && MathLib::isNullValue(nextArg->str()))
mathfunctionCallError(tok, 2);
}
// pow ( x , y) If x is zero, and y is negative --> division by zero
else if (Token::Match(tok, "pow ( %num% , %num% )") &&
MathLib::isNullValue(tok->strAt(2)) &&
MathLib::isNegative(tok->strAt(4))) {
mathfunctionCallError(tok, 2);
}
}
}
}
void CheckOther::mathfunctionCallError(const Token *tok, const unsigned int numParam)
{
if (tok) {
if (numParam == 1)
reportError(tok, Severity::error, "wrongmathcall", "Passing value " + tok->strAt(2) + " to " + tok->str() + "() leads to undefined result");
else if (numParam == 2)
reportError(tok, Severity::error, "wrongmathcall", "Passing value " + tok->strAt(2) + " and " + tok->strAt(4) + " to " + tok->str() + "() leads to undefined result");
} else
reportError(tok, Severity::error, "wrongmathcall", "Passing value " " to " "() leads to undefined result");
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
void CheckOther::checkCCTypeFunctions()
{
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (tok->varId() == 0 &&
Token::Match(tok, "isalnum|isalpha|iscntrl|isdigit|isgraph|islower|isprint|ispunct|isspace|isupper|isxdigit ( %num% ,|)") &&
MathLib::isNegative(tok->strAt(2))) {
cctypefunctionCallError(tok, tok->str(), tok->tokAt(2)->str());
}
}
}
void CheckOther::cctypefunctionCallError(const Token *tok, const std::string &functionName, const std::string &value)
{
reportError(tok, Severity::error, "wrongcctypecall", "Passing value " + value + " to " + functionName + "() cause undefined behavior, which may lead to a crash");
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
/** Is there a function with given name? */
static bool isFunction(const std::string &name, const Token *startToken)
{
const std::string pattern1(name + " (");
for (const Token *tok = startToken; tok; tok = tok->next()) {
// skip executable scopes etc
if (tok->str() == "(") {
tok = tok->link();
if (Token::simpleMatch(tok, ") {"))
tok = tok->next()->link();
else if (Token::simpleMatch(tok, ") const {"))
tok = tok->linkAt(2);
}
// function declaration/implementation found
if ((tok->str() == "*" || (tok->isName() && tok->str().find(":") ==std::string::npos))
&& Token::simpleMatch(tok->next(), pattern1.c_str()))
return true;
}
return false;
}
void CheckOther::checkMisusedScopedObject()
{
// Skip this check for .c files
if (_tokenizer->isC()) {
return;
}
const SymbolDatabase * const 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;
for (const Token *tok = scope->classStart; tok && tok != scope->classEnd; tok = tok->next()) {
if (Token::Match(tok, "[;{}] %var% (")
&& Token::simpleMatch(tok->linkAt(2), ") ;")
&& symbolDatabase->isClassOrStruct(tok->next()->str())
&& !isFunction(tok->next()->str(), _tokenizer->tokens())) {
tok = tok->next();
misusedScopeObjectError(tok, tok->str());
tok = tok->next();
}
}
}
}
void CheckOther::misusedScopeObjectError(const Token *tok, const std::string& varname)
{
reportError(tok, Severity::error,
"unusedScopedObject", "Instance of \"" + varname + "\" object destroyed immediately.");
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
void CheckOther::checkIncorrectStringCompare()
{
if (!_settings->isEnabled("style"))
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::Match(tok, ". substr ( %any% , %num% ) ==|!= %str%")) {
MathLib::bigint clen = MathLib::toLongNumber(tok->strAt(5));
std::size_t slen = Token::getStrLength(tok->tokAt(8));
if (clen != (int)slen) {
incorrectStringCompareError(tok->next(), "substr", tok->strAt(8), tok->strAt(5));
}
} else if (Token::Match(tok, "%str% ==|!= %var% . substr ( %any% , %num% )")) {
MathLib::bigint clen = MathLib::toLongNumber(tok->strAt(8));
std::size_t slen = Token::getStrLength(tok);
if (clen != (int)slen) {
incorrectStringCompareError(tok->next(), "substr", tok->str(), tok->strAt(8));
}
} else if (Token::Match(tok, "&&|%oror% %str% &&|%oror%|)")) {
// assert(condition && "debug message") would be considered a fp.
if (tok->str() == "&&" && tok->strAt(2) == ")" && tok->linkAt(2)->previous()->str() == "assert")
continue;
incorrectStringBooleanError(tok->next(), tok->strAt(1));
} else if (Token::Match(tok, "if|while|assert ( %str% &&|%oror%|)")) {
// assert("debug message" && condition) would be considered a fp.
if (tok->strAt(3) == "&&" && tok->str() == "assert")
continue;
incorrectStringBooleanError(tok->tokAt(2), tok->strAt(2));
}
}
}
void CheckOther::incorrectStringCompareError(const Token *tok, const std::string& func, const std::string &string, const std::string &len)
{
reportError(tok, Severity::warning, "incorrectStringCompare", "String literal " + string + " doesn't match length argument for " + func + "(" + len + ").");
}
void CheckOther::incorrectStringBooleanError(const Token *tok, const std::string& string)
{
reportError(tok, Severity::warning, "incorrectStringBooleanError", "A boolean comparison with the string literal " + string + " is always true.");
}
//-----------------------------------------------------------------------------
// check for duplicate expressions in if statements
// if (a) { } else if (a) { }
//-----------------------------------------------------------------------------
static bool expressionHasSideEffects(const Token *first, const Token *last)
{
for (const Token *tok = first; tok != last->next(); tok = tok->next()) {
// check for assignment
if (tok->isAssignmentOp())
return true;
// check for inc/dec
else if (tok->type() == Token::eIncDecOp)
return true;
// check for function call
else if (Token::Match(tok, "%var% (") &&
!(Token::Match(tok, "c_str|string") || tok->isStandardType()))
return true;
}
return false;
}
void CheckOther::checkDuplicateIf()
{
if (!_settings->isEnabled("style"))
return;
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
for (std::list<Scope>::const_iterator scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {
const Token* const tok = scope->classDef;
// only check if statements
if (scope->type != Scope::eIf || !tok)
continue;
std::map<std::string, const Token*> expressionMap;
// get the expression from the token stream
std::string expression = tok->tokAt(2)->stringifyList(tok->next()->link());
// save the expression and its location
expressionMap.insert(std::make_pair(expression, tok));
// find the next else if (...) statement
const Token *tok1 = scope->classEnd;
// check all the else if (...) statements
while (Token::simpleMatch(tok1, "} else if (") &&
Token::simpleMatch(tok1->linkAt(3), ") {")) {
// get the expression from the token stream
expression = tok1->tokAt(4)->stringifyList(tok1->linkAt(3));
// try to look up the expression to check for duplicates
std::map<std::string, const Token *>::iterator it = expressionMap.find(expression);
// found a duplicate
if (it != expressionMap.end()) {
// check for expressions that have side effects and ignore them
if (!expressionHasSideEffects(tok1->tokAt(4), tok1->linkAt(3)->previous()))
duplicateIfError(it->second, tok1->next());
}
// not a duplicate expression so save it and its location
else
expressionMap.insert(std::make_pair(expression, tok1->next()));
// find the next else if (...) statement
tok1 = tok1->linkAt(3)->next()->link();
}
}
}
void CheckOther::duplicateIfError(const Token *tok1, const Token *tok2)
{
std::list<const Token *> toks;
toks.push_back(tok2);
toks.push_back(tok1);
reportError(toks, Severity::style, "duplicateIf", "Found duplicate if expressions.\n"
"Finding the same expression more than once is suspicious and might indicate "
"a cut and paste or logic error. Please examine this code carefully to determine "
"if it is correct.");
}
//-----------------------------------------------------------------------------
// check for duplicate code in if and else branches
// if (a) { b = true; } else { b = true; }
//-----------------------------------------------------------------------------
void CheckOther::checkDuplicateBranch()
{
if (!_settings->isEnabled("style"))
return;
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
std::list<Scope>::const_iterator scope;
for (scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {
if (scope->type != Scope::eIf && scope->type != Scope::eElseIf)
continue;
// check all the code in the function for if (..) else
if (Token::simpleMatch(scope->classEnd, "} else {")) {
// save if branch code
std::string branch1 = scope->classStart->next()->stringifyList(scope->classEnd);
// save else branch code
std::string branch2 = scope->classEnd->tokAt(3)->stringifyList(scope->classEnd->linkAt(2));
// check for duplicates
if (branch1 == branch2)
duplicateBranchError(scope->classDef, scope->classEnd->next());
}
}
}
//-----------------------------------------------------------------------------
// Check for a free() of an invalid address
// char* p = malloc(100);
// free(p + 10);
//-----------------------------------------------------------------------------
void CheckOther::checkInvalidFree()
{
std::set<unsigned int> allocatedVariables;
for (const Token* tok = _tokenizer->tokens(); tok; tok = tok->next()) {
// Keep track of which variables were assigned addresses to newly-allocated memory
if (Token::Match(tok, "%var% = malloc|g_malloc|new")) {
allocatedVariables.insert(tok->varId());
}
// If these variables assigned new values before being used to free the memory, we can't
// say anything about whether the resulting expression is valid
else if (Token::Match(tok, "%var% =")) {
allocatedVariables.erase(tok->varId());
}
// If a variable that was previously assigned a newly-allocated memory location is
// added or subtracted from when used to free the memory, report an error.
else if (Token::Match(tok, "free|g_free|delete ( %any% +|- %any%") ||
Token::Match(tok, "delete [ ] ( %any% +|- %any%") ||
Token::Match(tok, "delete %any% +|- %any%")) {
int varIdx = tok->strAt(1) == "(" ? 2 :
tok->strAt(3) == "(" ? 4 : 1;
unsigned int var1 = tok->tokAt(varIdx)->varId();
unsigned int var2 = tok->tokAt(varIdx + 2)->varId();
if (allocatedVariables.find(var1) != allocatedVariables.end() ||
allocatedVariables.find(var2) != allocatedVariables.end()) {
invalidFreeError(tok);
}
}
// If the previously-allocated variable is passed in to another function
// as a parameter, it might be modified, so we shouldn't report an error
// if it is later used to free memory
else if (Token::Match(tok, "%var% (")) {
const Token* tok2 = Token::findmatch(tok->tokAt(1), "%var%", tok->linkAt(1));
while (tok2 != NULL) {
allocatedVariables.erase(tok2->varId());
tok2 = Token::findmatch(tok2->next(), "%var%", tok->linkAt(1));
}
}
}
}
void CheckOther::invalidFreeError(const Token *tok)
{
reportError(tok, Severity::error, "invalidFree", "Invalid memory address freed.");
}
//-----------------------------------------------------------------------------
// Check for double free
// free(p); free(p);
//-----------------------------------------------------------------------------
void CheckOther::checkDoubleFree()
{
std::set<unsigned int> freedVariables;
std::set<unsigned int> closeDirVariables;
for (const Token* tok = _tokenizer->tokens(); tok; tok = tok->next()) {
bool isUnknown = true;
// Keep track of any variables passed to "free()", "g_free()" or "closedir()",
// and report an error if the same variable is passed twice.
if (Token::Match(tok, "free|g_free|closedir ( %var% )")) {
unsigned int var = tok->tokAt(2)->varId();
if (var) {
if (Token::Match(tok, "free|g_free")) {
if (freedVariables.find(var) != freedVariables.end())
doubleFreeError(tok, tok->tokAt(2)->str());
else
freedVariables.insert(var);
} else if (tok->str() == "closedir") {
if (closeDirVariables.find(var) != closeDirVariables.end())
doubleCloseDirError(tok, tok->tokAt(2)->str());
else
closeDirVariables.insert(var);
}
}
}
// Keep track of any variables operated on by "delete" or "delete[]"
// and report an error if the same variable is delete'd twice.
else if (Token::Match(tok, "delete %var% ;") || Token::Match(tok, "delete [ ] %var% ;")) {
int varIdx = (tok->strAt(1) == "[") ? 3 : 1;
unsigned int var = tok->tokAt(varIdx)->varId();
if (var) {
if (freedVariables.find(var) != freedVariables.end())
doubleFreeError(tok, tok->tokAt(varIdx)->str());
else
freedVariables.insert(var);
}
}
// If this scope doesn't return, clear the set of previously freed variables
else if (tok->str() == "}" && _tokenizer->IsScopeNoReturn(tok, &isUnknown) && !isUnknown) {
freedVariables.clear();
closeDirVariables.clear();
}
// If this scope is a "for" or "while" loop that contains "break" or "continue",
// give up on trying to figure out the flow of execution and just clear the set
// of previously freed variables.
// TODO: There are false negatives. This bailout is only needed when the
// loop will exit without free()'ing the memory on the last iteration.
else if (tok->str() == "}" && tok->link() && tok->link()->linkAt(-1) &&
Token::Match(tok->link()->linkAt(-1)->previous(), "while|for") &&
Token::findmatch(tok->link()->linkAt(-1), "break|continue ;", tok) != NULL) {
freedVariables.clear();
closeDirVariables.clear();
}
// If a variable is passed to a function, remove it from the set of previously freed variables
else if (Token::Match(tok, "%var% (") && !Token::Match(tok, "printf|sprintf|snprintf|fprintf")) {
// If this is a new function definition, clear all variables
if (Token::simpleMatch(tok->next()->link(), ") {")) {
freedVariables.clear();
closeDirVariables.clear();
}
// If it is a function call, then clear those variables in its argument list
else if (Token::simpleMatch(tok->next()->link(), ") ;")) {
for (const Token* tok2 = tok->tokAt(2); tok2 != tok->linkAt(1); tok2 = tok2->next()) {
if (Token::Match(tok2, "%var%")) {
unsigned int var = tok2->varId();
if (var) {
freedVariables.erase(var);
closeDirVariables.erase(var);
}
}
}
}
}
// If a pointer is assigned a new value, remove it from the set of previously freed variables
else if (Token::Match(tok, "%var% =")) {
unsigned int var = tok->varId();
if (var) {
freedVariables.erase(var);
closeDirVariables.erase(var);
}
}
// Any control statements in-between delete, free() or closedir() statements
// makes it unclear whether any subsequent statements would be redundant.
if (Token::Match(tok, "if|else|for|while|break|continue|goto|return|throw|switch")) {
freedVariables.clear();
closeDirVariables.clear();
}
}
}
void CheckOther::doubleFreeError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::error, "doubleFree", "Memory pointed to by '" + varname +"' is freed twice.");
}
void CheckOther::doubleCloseDirError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::error, "doubleCloseDir", "Directory handle '" + varname +"' closed twice.");
}
void CheckOther::duplicateBranchError(const Token *tok1, const Token *tok2)
{
std::list<const Token *> toks;
toks.push_back(tok2);
toks.push_back(tok1);
reportError(toks, Severity::style, "duplicateBranch", "Found duplicate branches for if and else.\n"
"Finding the same code for an if branch and an else branch is suspicious and "
"might indicate a cut and paste or logic error. Please examine this code "
"carefully to determine if it is correct.");
}
namespace {
struct ExpressionTokens {
const Token *start;
const Token *end;
int count;
bool inconclusiveFunction;
ExpressionTokens(const Token *s, const Token *e): start(s), end(e), count(1), inconclusiveFunction(false) {}
};
struct FuncFilter {
FuncFilter(const Scope *scope, const Token *tok): _scope(scope), _tok(tok) {}
bool operator()(const Function* func) const {
bool matchingFunc = func->type == Function::eFunction &&
_tok->str() == func->token->str();
// either a class function, or a global function with the same name
return (_scope && _scope == func->nestedIn && matchingFunc) ||
(!_scope && matchingFunc);
}
const Scope *_scope;
const Token *_tok;
};
bool inconclusiveFunctionCall(const SymbolDatabase *symbolDatabase,
const std::list<const Function*> &constFunctions,
const ExpressionTokens &tokens)
{
const Token *start = tokens.start;
const Token *end = tokens.end;
// look for function calls between start and end...
for (const Token *tok = start; tok && tok != end; tok = tok->next()) {
if (tok != start && tok->str() == "(") {
// go back to find the function call.
const Token *prev = tok->previous();
if (!prev)
continue;
if (prev->str() == ">") {
// ignore template functions like boo<double>()
return true;
}
if (prev->isName()) {
const Variable *v = 0;
if (Token::Match(prev->tokAt(-2), "%var% .")) {
const Token *scope = prev->tokAt(-2);
v = symbolDatabase->getVariableFromVarId(scope->varId());
}
// hard coded list of safe, no-side-effect functions
if (v == 0 && Token::Match(prev, "strcmp|strncmp|strlen|memcmp|strcasecmp|strncasecmp"))
return false;
std::list<const Function*>::const_iterator it = std::find_if(constFunctions.begin(),
constFunctions.end(),
FuncFilter(v ? v->type(): 0, prev));
if (it == constFunctions.end())
return true;
}
}
}
return false;
}
class Expressions {
public:
Expressions(const SymbolDatabase *symbolDatabase, const
std::list<const Function*> &constFunctions)
: _start(0),
_lastTokens(0),
_symbolDatabase(symbolDatabase),
_constFunctions(constFunctions) { }
void endExpr(const Token *end) {
const std::string &e = _expression.str();
if (!e.empty()) {
std::map<std::string, ExpressionTokens>::iterator it = _expressions.find(e);
bool lastInconclusive = _lastTokens && _lastTokens->inconclusiveFunction;
if (it == _expressions.end()) {
ExpressionTokens exprTokens(_start, end);
exprTokens.inconclusiveFunction = lastInconclusive || inconclusiveFunctionCall(
_symbolDatabase, _constFunctions, exprTokens);
_expressions.insert(std::make_pair(e, exprTokens));
_lastTokens = &_expressions.find(e)->second;
} else {
ExpressionTokens &expr = it->second;
expr.count += 1;
expr.inconclusiveFunction = expr.inconclusiveFunction || lastInconclusive;
_lastTokens = &expr;
}
}
_expression.str("");
_start = 0;
}
void append(const Token *tok) {
if (!_start)
_start = tok;
_expression << tok->str();
}
std::map<std::string,ExpressionTokens> &getMap() {
return _expressions;
}
private:
std::map<std::string, ExpressionTokens> _expressions;
std::ostringstream _expression;
const Token *_start;
ExpressionTokens *_lastTokens;
const SymbolDatabase *_symbolDatabase;
const std::list<const Function*> &_constFunctions;
};
bool notconst(const Function* func)
{
return !func->isConst;
}
void getConstFunctions(const SymbolDatabase *symbolDatabase, std::list<const Function*> &constFunctions)
{
std::list<Scope>::const_iterator scope;
for (scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {
std::list<Function>::const_iterator func;
// only add const functions that do not have a non-const overloaded version
// since it is pretty much impossible to tell which is being called.
typedef std::map<std::string, std::list<const Function*> > StringFunctionMap;
StringFunctionMap functionsByName;
for (func = scope->functionList.begin(); func != scope->functionList.end(); ++func) {
functionsByName[func->tokenDef->str()].push_back(&*func);
}
for (StringFunctionMap::iterator it = functionsByName.begin();
it != functionsByName.end(); ++it) {
std::list<const Function*>::const_iterator nc = std::find_if(it->second.begin(), it->second.end(), notconst);
if (nc == it->second.end()) {
// ok to add all of them
constFunctions.splice(constFunctions.end(), it->second);
}
}
}
}
}
void CheckOther::checkExpressionRange(const std::list<const Function*> &constFunctions,
const Token *start,
const Token *end,
const std::string &toCheck)
{
if (!start || !end)
return;
Expressions expressions(_tokenizer->getSymbolDatabase(), constFunctions);
std::string opName;
int level = 0;
for (const Token *tok = start->next(); tok && tok != end; tok = tok->next()) {
if (tok->str() == ")")
level--;
else if (tok->str() == "(")
level++;
if (level == 0 && Token::Match(tok, toCheck.c_str())) {
opName = tok->str();
expressions.endExpr(tok);
} else {
expressions.append(tok);
}
}
expressions.endExpr(end);
std::map<std::string,ExpressionTokens>::const_iterator it = expressions.getMap().begin();
for (; it != expressions.getMap().end(); ++it) {
// check expression..
bool valid = true;
unsigned int parenthesis = 0; // ()
unsigned int brackets = 0; // []
// taking address?
if (Token::Match(it->second.end->previous(), "%op% &")) {
continue;
}
for (const Token *tok = it->second.start; tok && tok != it->second.end; tok = tok->next()) {
if (tok->str() == "(") {
++parenthesis;
} else if (tok->str() == ")") {
if (parenthesis == 0) {
valid = false;
break;
}
--parenthesis;
} else if (tok->str() == "[") {
++brackets;
} else if (tok->str() == "]") {
if (brackets == 0) {
valid = false;
break;
}
--brackets;
} else if (tok->type() == Token::eIncDecOp) {
valid = false;
break;
}
}
if (!valid || parenthesis!=0 || brackets!=0)
continue;
const ExpressionTokens &expr = it->second;
if (expr.count > 1 && !expr.inconclusiveFunction) {
duplicateExpressionError(expr.start, expr.start, opName);
}
}
}
void CheckOther::complexDuplicateExpressionCheck(const std::list<const Function*> &constFunctions,
const Token *classStart,
const std::string &toCheck,
const std::string &alt)
{
std::string statementStart(",|=|?|:|return");
if (!alt.empty())
statementStart += "|" + alt;
std::string statementEnd(";|,|?|:");
if (!alt.empty())
statementEnd += "|" + alt;
for (const Token *tok = classStart; tok && tok != classStart->link(); tok = tok->next()) {
if (!Token::Match(tok, toCheck.c_str()))
continue;
// look backward for the start of the statement
const Token *start = 0;
int level = 0;
for (const Token *tok1 = tok->previous(); tok1 && tok1 != classStart; tok1 = tok1->previous()) {
if (tok1->str() == ")")
level++;
else if (tok1->str() == "(")
level--;
if (level < 0 || (level == 0 && Token::Match(tok1, statementStart.c_str()))) {
start = tok1;
break;
}
}
const Token *end = 0;
level = 0;
// look for the end of the statement
for (const Token *tok1 = tok->next(); tok1 && tok1 != classStart->link(); tok1 = tok1->next()) {
if (tok1->str() == ")")
level--;
else if (tok1->str() == "(")
level++;
if (level < 0 || (level == 0 && Token::Match(tok1, statementEnd.c_str()))) {
end = tok1;
break;
}
}
checkExpressionRange(constFunctions, start, end, toCheck);
}
}
//---------------------------------------------------------------------------
// check for the same expression on both sides of an operator
// (x == x), (x && x), (x || x)
// (x.y == x.y), (x.y && x.y), (x.y || x.y)
//---------------------------------------------------------------------------
void CheckOther::checkDuplicateExpression()
{
if (!_settings->isEnabled("style"))
return;
// Parse all executing scopes..
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
std::list<Scope>::const_iterator scope;
std::list<const Function*> constFunctions;
getConstFunctions(symbolDatabase, constFunctions);
for (scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {
// only check functions
if (scope->type != Scope::eFunction)
continue;
complexDuplicateExpressionCheck(constFunctions, scope->classStart, "%or%", "");
complexDuplicateExpressionCheck(constFunctions, scope->classStart, "%oror%", "");
complexDuplicateExpressionCheck(constFunctions, scope->classStart, "&", "%oror%|%or%");
complexDuplicateExpressionCheck(constFunctions, scope->classStart, "&&", "%oror%|%or%");
for (const Token *tok = scope->classStart; tok && tok != scope->classStart->link(); tok = tok->next()) {
if (Token::Match(tok, ",|=|return|(|&&|%oror% %var% ==|!=|<=|>=|<|>|- %var% )|&&|%oror%|;|,") &&
tok->strAt(1) == tok->strAt(3)) {
// float == float and float != float are valid NaN checks
if (Token::Match(tok->tokAt(2), "==|!=") && tok->next()->varId()) {
const Variable * var = symbolDatabase->getVariableFromVarId(tok->next()->varId());
if (var && var->typeStartToken() == var->typeEndToken()) {
if (Token::Match(var->typeStartToken(), "float|double"))
continue;
}
}
// If either variable token is an expanded macro then
// don't write the warning
if (tok->next()->isExpandedMacro() || tok->tokAt(3)->isExpandedMacro())
continue;
duplicateExpressionError(tok->next(), tok->tokAt(3), tok->strAt(2));
} else if (Token::Match(tok, ",|=|return|(|&&|%oror% %var% . %var% ==|!=|<=|>=|<|>|- %var% . %var% )|&&|%oror%|;|,") &&
tok->strAt(1) == tok->strAt(5) && tok->strAt(3) == tok->strAt(7)) {
// If either variable token is an expanded macro then
// don't write the warning
if (tok->next()->isExpandedMacro() || tok->tokAt(6)->isExpandedMacro())
continue;
duplicateExpressionError(tok->next(), tok->tokAt(6), tok->strAt(4));
}
}
}
}
void CheckOther::duplicateExpressionError(const Token *tok1, const Token *tok2, const std::string &op)
{
std::list<const Token *> toks;
toks.push_back(tok2);
toks.push_back(tok1);
reportError(toks, Severity::style, "duplicateExpression", "Same expression on both sides of \'" + op + "\'.\n"
"Finding the same expression on both sides of an operator is suspicious and might "
"indicate a cut and paste or logic error. Please examine this code carefully to "
"determine if it is correct.");
}
//---------------------------------------------------------------------------
// Check for string comparison involving two static strings.
// if(strcmp("00FF00","00FF00")==0) // <- statement is always true
//---------------------------------------------------------------------------
void CheckOther::checkAlwaysTrueOrFalseStringCompare()
{
if (!_settings->isEnabled("style"))
return;
const char pattern1[] = "strncmp|strcmp|stricmp|strcmpi|strcasecmp|wcscmp ( %str% , %str% ";
const char pattern2[] = "QString :: compare ( %str% , %str% )";
const char pattern3[] = "strncmp|strcmp|stricmp|strcmpi|strcasecmp|wcscmp ( %var% , %var% ";
const Token *tok = _tokenizer->tokens();
while (tok && (tok = Token::findmatch(tok, pattern1)) != NULL) {
const std::string &str1 = tok->strAt(2);
const std::string &str2 = tok->strAt(4);
alwaysTrueFalseStringCompareError(tok, str1, str2);
tok = tok->tokAt(5);
}
tok = _tokenizer->tokens();
while (tok && (tok = Token::findmatch(tok, pattern2)) != NULL) {
const std::string &str1 = tok->strAt(4);
const std::string &str2 = tok->strAt(6);
alwaysTrueFalseStringCompareError(tok, str1, str2);
tok = tok->tokAt(7);
}
tok = _tokenizer->tokens();
while (tok && (tok = Token::findmatch(tok, pattern3)) != NULL) {
const std::string &str1 = tok->strAt(2);
const std::string &str2 = tok->strAt(4);
if (str1 == str2)
alwaysTrueStringVariableCompareError(tok, str1, str2);
tok = tok->tokAt(5);
}
tok = _tokenizer->tokens();
while (tok && (tok = Token::findmatch(tok, "!!+ %str% ==|!= %str% !!+")) != NULL) {
const std::string &str1 = tok->strAt(1);
const std::string &str2 = tok->strAt(3);
alwaysTrueFalseStringCompareError(tok, str1, str2);
tok = tok->tokAt(5);
}
}
void CheckOther::alwaysTrueFalseStringCompareError(const Token *tok, const std::string& str1, const std::string& str2)
{
const std::size_t stringLen = 10;
const std::string string1 = (str1.size() < stringLen) ? str1 : (str1.substr(0, stringLen-2) + "..");
const std::string string2 = (str2.size() < stringLen) ? str2 : (str2.substr(0, stringLen-2) + "..");
reportError(tok, Severity::warning, "staticStringCompare",
"Unnecessary comparison of static strings.\n"
"The compared strings, '" + string1 + "' and '" + string2 + "', are always " + (str1==str2?"identical":"unequal") + ". "
"Therefore the comparison is unnecessary and looks suspicious.");
}
void CheckOther::alwaysTrueStringVariableCompareError(const Token *tok, const std::string& str1, const std::string& str2)
{
reportError(tok, Severity::warning, "stringCompare",
"Comparison of identical string variables.\n"
"The compared strings, '" + str1 + "' and '" + str2 + "', are identical. "
"This could be a logic bug.");
}
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
void CheckOther::checkSuspiciousStringCompare()
{
if (!_settings->isEnabled("style"))
return;
const SymbolDatabase* symbolDatabase = _tokenizer->getSymbolDatabase();
for (const Token* tok = _tokenizer->list.front(); tok && tok->tokAt(3); tok = tok->next()) {
if (tok->next()->type() != Token::eComparisonOp)
continue;
const Token* varTok = tok;
const Token* litTok = tok->tokAt(2);
if (varTok->strAt(-1) == "+" || litTok->strAt(1) == "+")
continue;
if ((varTok->type() == Token::eString || varTok->type() == Token::eVariable) && (litTok->type() == Token::eString || litTok->type() == Token::eVariable) && litTok->type() != varTok->type()) {
if (varTok->type() == Token::eString)
std::swap(varTok, litTok);
const Variable* var = symbolDatabase->getVariableFromVarId(varTok->varId());
if (var && var->isPointer())
suspiciousStringCompareError(tok, var->name());
}
}
}
void CheckOther::suspiciousStringCompareError(const Token* tok, const std::string& var)
{
reportError(tok, Severity::warning, "literalWithCharPtrCompare",
"String literal compared with variable '" + var + "'. Did you intend to use strcmp() instead?");
}
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
void CheckOther::checkModuloAlwaysTrueFalse()
{
for (const Token* tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::Match(tok, "% %num% ==|!=|<=|<|>|>= %num%") && (!tok->tokAt(4) || !tok->tokAt(4)->isArithmeticalOp())) {
if (MathLib::isLessEqual(tok->strAt(1), tok->strAt(3)))
moduloAlwaysTrueFalseError(tok, tok->strAt(1));
}
}
}
void CheckOther::moduloAlwaysTrueFalseError(const Token* tok, const std::string& maxVal)
{
reportError(tok, Severity::warning, "moduloAlwaysTrueFalse",
"Comparison of modulo result is predetermined, because it is always less than " + maxVal + ".");
}
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
void CheckOther::sizeofsizeof()
{
if (!_settings->isEnabled("style"))
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::Match(tok, "sizeof (| sizeof")) {
sizeofsizeofError(tok);
tok = tok->next();
}
}
}
void CheckOther::sizeofsizeofError(const Token *tok)
{
reportError(tok, Severity::warning,
"sizeofsizeof", "Calling sizeof for 'sizeof'.\n"
"Calling sizeof for 'sizeof looks like a suspicious code and "
"most likely there should be just one 'sizeof'. The current "
"code is equivalent to 'sizeof(size_t)'");
}
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
void CheckOther::sizeofCalculation()
{
if (!_settings->isEnabled("style"))
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::simpleMatch(tok, "sizeof (")) {
const Token* const end = tok->linkAt(1);
for (const Token *tok2 = tok->tokAt(2); tok2 != end; tok2 = tok2->next()) {
if (tok2->isOp() && (!tok2->isExpandedMacro() || _settings->inconclusive) && !Token::Match(tok2, ">|<|&") && (Token::Match(tok2->previous(), "%var%") || !Token::Match(tok2, "*"))) {
if (!(Token::Match(tok2->previous(), "%type%") || Token::Match(tok2->next(), "%type%"))) {
sizeofCalculationError(tok2, tok2->isExpandedMacro());
break;
}
}
}
}
}
}
void CheckOther::sizeofCalculationError(const Token *tok, bool inconclusive)
{
reportError(tok, Severity::warning,
"sizeofCalculation", "Found calculation inside sizeof()", inconclusive);
}
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
void CheckOther::checkAssignBoolToPointer()
{
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::Match(tok, "!!* %var% = %bool% ;")) {
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
const Variable *var1(symbolDatabase->getVariableFromVarId(tok->next()->varId()));
// Is variable a pointer?
if (var1 && var1->isPointer())
assignBoolToPointerError(tok->next());
}
}
}
void CheckOther::assignBoolToPointerError(const Token *tok)
{
reportError(tok, Severity::error, "assignBoolToPointer",
"Assigning bool value to pointer (converting bool value to address)");
}
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
void CheckOther::checkComparisonOfBoolExpressionWithInt()
{
if (!_settings->isEnabled("style"))
return;
const SymbolDatabase* symbolDatabase = _tokenizer->getSymbolDatabase();
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
// Skip template parameters
if (tok->str() == "<" && tok->link()) {
tok = tok->link();
continue;
}
const Token* numTok = 0;
const Token* opTok = 0;
char op = 0;
if (Token::Match(tok, "&&|%oror% %any% ) >|>=|==|!=|<=|< %any%")) {
numTok = tok->tokAt(4);
opTok = tok->tokAt(3);
if (Token::Match(opTok, "<|>"))
op = opTok->str()[0];
} else if (Token::Match(tok, "%any% >|>=|==|!=|<=|< ( %any% &&|%oror%")) {
numTok = tok;
opTok = tok->next();
if (Token::Match(opTok, "<|>"))
op = opTok->str()[0]=='>'?'<':'>';
}
else if (Token::Match(tok, "! %var% >|>=|==|!=|<=|< %any%")) {
numTok = tok->tokAt(3);
opTok = tok->tokAt(2);
if (Token::Match(opTok, "<|>"))
op = opTok->str()[0];
} else if (Token::Match(tok, "%any% >|>=|==|!=|<=|< ! %var%")) {
numTok = tok;
opTok = tok->next();
if (Token::Match(opTok, "<|>"))
op = opTok->str()[0]=='>'?'<':'>';
}
if (numTok && opTok) {
if (numTok->isNumber()) {
if (((numTok->str() != "0" && numTok->str() != "1") || !Token::Match(opTok, "!=|==")) && !((op == '<' && numTok->str() == "1") || (op == '>' && numTok->str() == "0")))
comparisonOfBoolExpressionWithIntError(tok, true);
} else if (isNonBoolStdType(symbolDatabase->getVariableFromVarId(numTok->varId())))
comparisonOfBoolExpressionWithIntError(tok, false);
}
}
}
void CheckOther::comparisonOfBoolExpressionWithIntError(const Token *tok, bool n0o1)
{
if (n0o1)
reportError(tok, Severity::warning, "compareBoolExpressionWithInt",
"Comparison of a boolean expression with an integer other than 0 or 1.");
else
reportError(tok, Severity::warning, "compareBoolExpressionWithInt",
"Comparison of a boolean expression with an integer.");
}
//---------------------------------------------------------------------------
// Check testing sign of unsigned variables and pointers.
//---------------------------------------------------------------------------
void CheckOther::checkSignOfUnsignedVariable()
{
if (!_settings->isEnabled("style"))
return;
const bool inconclusive = _tokenizer->codeWithTemplates();
if (inconclusive && !_settings->inconclusive)
return;
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
std::list<Scope>::const_iterator scope;
for (scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {
// only check functions
if (scope->type != Scope::eFunction)
continue;
// check all the code in the function
for (const Token *tok = scope->classStart; tok && tok != scope->classEnd; tok = tok->next()) {
if (Token::Match(tok, "%var% <|<= 0") && tok->varId() && !Token::Match(tok->previous(), "++|--|)|+|-|*|/|~|<<|>>") && !Token::Match(tok->tokAt(3), "+|-")) {
const Variable * var = symbolDatabase->getVariableFromVarId(tok->varId());
if (var && var->typeEndToken()->isUnsigned())
unsignedLessThanZeroError(tok, var->name(), inconclusive);
else if (var && var->isPointer() && tok->strAt(-1) != "*")
pointerLessThanZeroError(tok, inconclusive);
} else if (Token::Match(tok, "0 >|>= %var%") && tok->tokAt(2)->varId() && !Token::Match(tok->tokAt(3), "+|-|*|/") && !Token::Match(tok->previous(), "+|-|<<|>>|~")) {
const Variable * var = symbolDatabase->getVariableFromVarId(tok->tokAt(2)->varId());
if (var && var->typeEndToken()->isUnsigned())
unsignedLessThanZeroError(tok, var->name(), inconclusive);
else if (var && var->isPointer() && !Token::Match(tok->tokAt(3), "[.[]"))
pointerLessThanZeroError(tok, inconclusive);
} else if (Token::Match(tok, "0 <= %var%") && tok->tokAt(2)->varId() && !Token::Match(tok->tokAt(3), "+|-|*|/") && !Token::Match(tok->previous(), "+|-|<<|>>|~")) {
const Variable * var = symbolDatabase->getVariableFromVarId(tok->tokAt(2)->varId());
if (var && var->typeEndToken()->isUnsigned())
unsignedPositiveError(tok, var->name(), inconclusive);
else if (var && var->isPointer() && !Token::Match(tok->tokAt(3), "[.[]"))
pointerPositiveError(tok, inconclusive);
} else if (Token::Match(tok, "%var% >= 0") && tok->varId() && !Token::Match(tok->previous(), "++|--|)|+|-|*|/|~|<<|>>") && !Token::Match(tok->tokAt(3), "+|-")) {
const Variable * var = symbolDatabase->getVariableFromVarId(tok->varId());
if (var && var->typeEndToken()->isUnsigned())
unsignedPositiveError(tok, var->name(), inconclusive);
else if (var && var->isPointer() && tok->strAt(-1) != "*")
pointerPositiveError(tok, inconclusive);
}
}
}
}
void CheckOther::unsignedLessThanZeroError(const Token *tok, const std::string &varname, bool inconclusive)
{
if (inconclusive) {
reportError(tok, Severity::style, "unsignedLessThanZero",
"Checking if unsigned variable '" + varname + "' is less than zero. This might be a false warning.\n"
"Checking if unsigned variable '" + varname + "' is less than zero. An unsigned "
"variable will never be negative so it is either pointless or an error to check if it is. "
"It's not known if the used constant is a template parameter or not and therefore "
"this message might be a false warning", true);
} else {
reportError(tok, Severity::style, "unsignedLessThanZero",
"Checking if unsigned variable '" + varname + "' is less than zero.\n"
"The unsigned variable '" + varname + "' will never be negative so it "
"is either pointless or an error to check if it is.");
}
}
void CheckOther::pointerLessThanZeroError(const Token *tok, bool inconclusive)
{
reportError(tok, Severity::style, "pointerLessThanZero",
"A pointer can not be negative so it is either pointless or an error to check if it is.", inconclusive);
}
void CheckOther::unsignedPositiveError(const Token *tok, const std::string &varname, bool inconclusive)
{
if (inconclusive) {
reportError(tok, Severity::style, "unsignedPositive",
"An unsigned variable '" + varname + "' can't be negative so it is unnecessary to test it. This might be a false warning.\n"
"An unsigned variable '" + varname + "' can't be negative so it is unnecessary to test it. "
"It's not known if the used constant is a "
"template parameter or not and therefore this message might be a false warning", true);
} else {
reportError(tok, Severity::style, "unsignedPositive",
"An unsigned variable '" + varname + "' can't be negative so it is unnecessary to test it.");
}
}
void CheckOther::pointerPositiveError(const Token *tok, bool inconclusive)
{
reportError(tok, Severity::style, "pointerPositive",
"A pointer can not be negative so it is either pointless or an error to check if it is not.", inconclusive);
}
/*
This check rule works for checking the "const A a = getA()" usage when getA() returns "const A &" or "A &".
In most scenarios, "const A & a = getA()" will be more efficient.
*/
void CheckOther::checkRedundantCopy()
{
if (!_settings->isEnabled("performance"))
return;
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
for (const Token *tok = _tokenizer->tokens(); tok; tok=tok->next()) {
const char *expect_end_token;
if (Token::Match(tok, "const %type% %var% =")) {
//match "const A a =" usage
expect_end_token = ";";
} else if (Token::Match(tok, "const %type% %var% (")) {
//match "const A a (" usage
expect_end_token = ")";
} else {
continue;
}
if (tok->strAt(1) == tok->strAt(4)) //avoid "const A a = A();"
continue;
if (!symbolDatabase->isClassOrStruct(tok->next()->str())) //avoid when %type% is standard type
continue;
const Token *var_tok = tok->tokAt(2);
tok = tok->tokAt(4);
while (tok &&Token::Match(tok,"%var% ."))
tok = tok->tokAt(2);
if (!Token::Match(tok, "%var% ("))
break;
const Token *match_end = (tok->next()->link()!=NULL)?tok->next()->link()->next():NULL;
if (match_end==NULL || !Token::Match(match_end,expect_end_token)) //avoid usage like "const A a = getA()+3"
break;
const Token *fToken = _tokenizer->getFunctionTokenByName(tok->str().c_str());
if (fToken &&fToken->previous() && fToken->previous()->str() == "&") {
redundantCopyError(var_tok,var_tok->str());
}
}
}
void CheckOther::redundantCopyError(const Token *tok,const std::string& varname)
{
reportError(tok, Severity::performance,"redundantCopyLocalConst",
"Use const reference for "+varname+" to avoid unnecessary data copying.\n"
"The const "+varname+" gets a copy of the data since const reference is not used. You can avoid the unnecessary data copying by converting "+varname+" to const reference instead of just const.");
}
//---------------------------------------------------------------------------
// Checking for shift by negative values
//---------------------------------------------------------------------------
void CheckOther::checkNegativeBitwiseShift()
{
for (const Token *tok = _tokenizer->tokens(); tok ; tok = tok->next()) {
if (Token::Match(tok,"%var% >>|<< %num%") || Token::Match(tok,"%num >>|<< %num%")) {
if ((tok->strAt(2))[0] == '-')
negativeBitwiseShiftError(tok);
}
}
}
void CheckOther::negativeBitwiseShiftError(const Token *tok)
{
reportError(tok, Severity::error, "shiftNegative", "Shifting by a negative value.");
}
//---------------------------------------------------------------------------
// Check for incompletely filled buffers.
//---------------------------------------------------------------------------
void CheckOther::checkIncompleteArrayFill()
{
if (!_settings->inconclusive || !_settings->isEnabled("style"))
return;
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
for (const Token* tok = _tokenizer->list.front(); tok; tok = tok->next()) {
if (Token::Match(tok, "memset|memcpy|memmove ( %var% ,") && Token::Match(tok->linkAt(1)->tokAt(-2), ", %num% )")) {
const Variable* var = symbolDatabase->getVariableFromVarId(tok->tokAt(2)->varId());
if (!var || !var->isArray() || var->dimensions().empty() || !var->dimension(0))
continue;
if (MathLib::toLongNumber(tok->linkAt(1)->strAt(-1)) == var->dimension(0)) {
unsigned int size = _tokenizer->sizeOfType(var->typeStartToken());
if ((size != 1 && size != 100 && size != 0) || Token::Match(var->typeEndToken(), "*"))
incompleteArrayFillError(tok, var->name(), tok->str(), false);
else if (var->typeStartToken()->str() == "bool" && _settings->isEnabled("portability")) // sizeof(bool) is not 1 on all platforms
incompleteArrayFillError(tok, var->name(), tok->str(), true);
}
}
}
}
void CheckOther::incompleteArrayFillError(const Token* tok, const std::string& buffer, const std::string& function, bool boolean)
{
if (boolean)
reportError(tok, Severity::portability, "incompleteArrayFill",
"Array '" + buffer + "' might be filled incompletely. Did you forget to multiply the size given to '" + function + "()' with 'sizeof(*" + buffer + ")'?\n"
"The array '" + buffer + "' is filled incompletely. The function '" + function + "()' needs the size given in bytes, but the type 'bool' is larger than 1 on some platforms. Did you forget to multiply the size with 'sizeof(*" + buffer + ")'?", true);
else
reportError(tok, Severity::warning, "incompleteArrayFill",
"Array '" + buffer + "' is filled incompletely. Did you forget to multiply the size given to '" + function + "()' with 'sizeof(*" + buffer + ")'?\n"
"The array '" + buffer + "' is filled incompletely. The function '" + function + "()' needs the size given in bytes, but an element of the given array is larger than one byte. Did you forget to multiply the size with 'sizeof(*" + buffer + ")'?", true);
}
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