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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 (tok2 && tok2->str() == "*")
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. Postfix 'operator++' is executed before '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::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
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::simpleMatch(tok->tokAt(-2), "sizeof (")) { // Other usage of variable
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();