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cppcheck/lib/checkother.cpp

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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2011 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 <cctype> // std::isupper
#include <cmath> // fabs()
#include <stack>
//---------------------------------------------------------------------------
// 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\n"
);
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
void CheckOther::clarifyCalculation()
{
if (!_settings->isEnabled("style"))
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
{
if (tok->strAt(1) == "?")
{
// condition
const Token *cond = tok;
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->strAt(-1) == "*" && (cond->isName() || cond->isNumber()))
cond = cond->tokAt(-2);
if (!cond)
continue;
// first multiplication operand
if (cond->str() == ")")
{
clarifyCalculationError(cond, op);
}
else if (cond->isName() || cond->isNumber())
{
if (Token::Match(cond->previous(),("return|=|+|-|,|(|"+op).c_str()))
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;
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 (Token::Match(tok2, "<|<=|==|!=|>|>="))
{
// This might be a template
if (!code_is_c() && Token::Match(tok2->previous(), "%var% <"))
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, "!|<|<=|==|!=|>|>="))
{
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(tok, "<|>") && (Token::Match(tok2, "& ,|>") ||
Token::Match(tok2->previous(), "const &")))
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);
}
//---------------------------------------------------------------------------
// if (bool & bool) -> if (bool && bool)
// if (bool | bool) -> if (bool || bool)
//---------------------------------------------------------------------------
void CheckOther::checkBitwiseOnBoolean()
{
if (!_settings->isEnabled("style"))
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
{
if (Token::Match(tok, "(|.|return %var% [&|]"))
{
if (tok->next()->varId())
{
const Variable *var = _tokenizer->getSymbolDatabase()->getVariableFromVarId(tok->next()->varId());
if (var && (var->typeStartToken() == var->typeEndToken()) &&
var->typeStartToken()->str() == "bool")
{
bitwiseOnBooleanError(tok->next(), tok->next()->str(), tok->strAt(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 + " ?");
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
void CheckOther::warningOldStylePointerCast()
{
if (!_settings->isEnabled("style") ||
(_tokenizer->tokens() && _tokenizer->fileLine(_tokenizer->tokens()).find(".cpp") == std::string::npos))
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;
int addToIndex = 0;
if (tok->tokAt(1)->str() == "const")
addToIndex = 1;
if (tok->tokAt(4 + addToIndex)->str() == "const")
continue;
// Is "type" a class?
const std::string pattern("class " + tok->tokAt(1 + addToIndex)->str());
if (!Token::findmatch(_tokenizer->tokens(), pattern.c_str()))
continue;
cstyleCastError(tok);
}
}
void CheckOther::cstyleCastError(const Token *tok)
{
reportError(tok, Severity::style, "cstyleCast", "C-style pointer casting");
}
//---------------------------------------------------------------------------
// fflush(stdin) <- fflush only applies to output streams in ANSI C
//---------------------------------------------------------------------------
void CheckOther::checkFflushOnInputStream()
{
const Token *tok = _tokenizer->tokens();
while (tok && ((tok = Token::findmatch(tok, "fflush ( stdin )")) != NULL))
{
fflushOnInputStreamError(tok, tok->strAt(2));
tok = tok->tokAt(4);
}
}
void CheckOther::fflushOnInputStreamError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::error,
"fflushOnInputStream", "fflush() called on input stream \"" + varname + "\" may result in undefined behaviour");
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
void CheckOther::checkSizeofForNumericParameter()
{
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
{
if (Token::Match(tok, "sizeof ( %num% )")
|| Token::Match(tok, "sizeof ( - %num% )")
|| Token::Match(tok, "sizeof %num%")
|| Token::Match(tok, "sizeof - %num%")
)
{
sizeofForNumericParameterError(tok);
}
}
}
void CheckOther::sizeofForNumericParameterError(const Token *tok)
{
reportError(tok, Severity::error,
"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, this code:\n"
" int f() {\n"
" return sizeof(10);\n"
" }\n"
" returns 4 (in 32-bit systems) or 8 (in 64-bit systems) instead of 10."
);
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
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%"))
{
int tokIdx = 1;
if (tok->tokAt(tokIdx)->str() == "(")
{
++tokIdx;
}
if (tok->tokAt(tokIdx)->varId() > 0)
{
const Variable *var = symbolDatabase->getVariableFromVarId(tok->tokAt(tokIdx)->varId());
if (var)
{
const Token *declTok = var->nameToken();
if (Token::simpleMatch(declTok->next(), "["))
{
declTok = declTok->next()->link();
// multidimensional array
while (Token::simpleMatch(declTok->next(), "["))
{
declTok = declTok->next()->link();
}
if (!(Token::Match(declTok->next(), "= %str%")) && !(Token::simpleMatch(declTok->next(), "= {")) && !(Token::simpleMatch(declTok->next(), ";")))
{
if (Token::simpleMatch(declTok->next(), ","))
{
declTok = declTok->next();
while (!Token::simpleMatch(declTok, ";"))
{
if (Token::simpleMatch(declTok, ")"))
{
sizeofForArrayParameterError(tok);
break;
}
if (Token::Match(declTok, "(|[|{"))
{
declTok = declTok->link();
}
declTok = declTok->next();
}
}
}
if (Token::simpleMatch(declTok->next(), ")"))
{
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)."
);
}
//---------------------------------------------------------------------------
// 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()
{
const char switchPattern[] = "switch ( %any% ) { case";
const char breakPattern[] = "break|continue|return|exit|goto|throw";
const char functionPattern[] = "%var% (";
// Find the beginning of a switch. E.g.:
// switch (var) { ...
const Token *tok = Token::findmatch(_tokenizer->tokens(), switchPattern);
while (tok)
{
// Check the contents of the switch statement
std::map<unsigned int, const Token*> varsAssigned;
int indentLevel = 0;
for (const Token *tok2 = tok->tokAt(5); tok2; 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)
varsAssigned.erase(tok3->varId());
else if (Token::Match(tok3, functionPattern) || Token::Match(tok3, breakPattern))
varsAssigned.clear();
}
tok2 = endOfConditional;
}
else
++ indentLevel;
}
else if (tok2->str() == "}")
{
-- indentLevel;
// End of the switch block
if (indentLevel < 0)
break;
}
// 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)
{
std::map<unsigned int, const Token*>::iterator i = varsAssigned.find(tok2->varId());
if (i == varsAssigned.end())
varsAssigned[tok2->varId()] = tok2;
else
redundantAssignmentInSwitchError(i->second, i->second->str());
}
// 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)
varsAssigned.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))
varsAssigned.clear();
}
tok = Token::findmatch(tok->next(), switchPattern);
}
}
void CheckOther::redundantAssignmentInSwitchError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::warning,
"redundantAssignInSwitch", "Redundant assignment of \"" + varname + "\" in switch");
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
void CheckOther::checkSwitchCaseFallThrough()
{
if (!(_settings->isEnabled("style") && _settings->experimental))
return;
const char switchPattern[] = "switch (";
const char breakPattern[] = "break|continue|return|exit|goto|throw";
// Find the beginning of a switch. E.g.:
// switch (var) { ...
const Token *tok = Token::findmatch(_tokenizer->tokens(), switchPattern);
while (tok)
{
// 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 = tok->tokAt(1)->link()->tokAt(2); tok2; tok2 = tok2->next())
{
if (Token::simpleMatch(tok2, "if ("))
{
tok2 = tok2->tokAt(1)->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->tokAt(1)->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->tokAt(1);
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->tokAt(1)->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::Match(tok2, switchPattern))
{
// skip over nested switch, we'll come to that soon
tok2 = tok2->tokAt(1)->link()->next()->link();
}
else if (Token::Match(tok2, breakPattern))
{
if (loopnest.empty())
{
justbreak = true;
}
tok2 = Token::findmatch(tok2, ";");
}
else if (Token::Match(tok2, "case|default"))
{
if (!justbreak && !firstcase)
{
switchCaseFallThrough(tok2);
}
tok2 = Token::findmatch(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;
}
}
tok = Token::findmatch(tok->next(), switchPattern);
}
}
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
//---------------------------------------------------------------------------
void CheckOther::checkSelfAssignment()
{
if (!_settings->isEnabled("style"))
return;
// POD variables..
std::set<unsigned int> pod;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
{
if (tok->isStandardType() && Token::Match(tok->tokAt(2), "[,);]") && tok->next()->varId())
pod.insert(tok->next()->varId());
}
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() &&
pod.find(tok->varId()) != pod.end())
{
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->tokAt(-2)->link()->previous();
// find the '}' that terminates the 'else'-block
const Token *else_end = tok->tokAt(6)->link();
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)
{
const Token* varTok = Token::findmatch(tok->tokAt(2), "%var% --|++|+=|-=|*=|/=|&=|^=|=", endTok);
if (varTok)
{
assignmentInAssertError(tok, varTok->str());
}
else if (NULL != (varTok = Token::findmatch(tok->tokAt(2), "--|++ %var%", endTok)))
{
assignmentInAssertError(tok, varTok->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.
//---------------------------------------------------------------------------
void CheckOther::checkIncorrectLogicOperator()
{
if (!_settings->isEnabled("style"))
return;
const char conditionPattern[] = "if|while (";
const Token *tok = Token::findmatch(_tokenizer->tokens(), conditionPattern);
const Token *endTok = tok ? tok->next()->link() : NULL;
while (tok && endTok)
{
// 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 *logicTok = NULL, *term1Tok = NULL, *term2Tok = NULL;
const Token *op1Tok = NULL, *op2Tok = NULL, *op3Tok = NULL, *nextTok = NULL;
if (NULL != (logicTok = Token::findmatch(tok, "( %any% !=|==|<|>|>=|<= %any% ) &&|%oror% ( %any% !=|==|<|>|>=|<= %any% ) %any%", endTok)))
{
term1Tok = logicTok->next();
term2Tok = logicTok->tokAt(7);
op1Tok = logicTok->tokAt(2);
op2Tok = logicTok->tokAt(5);
op3Tok = logicTok->tokAt(8);
nextTok = logicTok->tokAt(11);
}
else if (NULL != (logicTok = Token::findmatch(tok, "%any% !=|==|<|>|>=|<= %any% &&|%oror% %any% !=|==|<|>|>=|<= %any% %any%", endTok)))
{
term1Tok = logicTok;
term2Tok = logicTok->tokAt(4);
op1Tok = logicTok->tokAt(1);
op2Tok = logicTok->tokAt(3);
op3Tok = logicTok->tokAt(5);
nextTok = logicTok->tokAt(7);
}
if (logicTok)
{
// Find the common variable and the two different-valued constants
unsigned int variableTested = 0;
std::string firstConstant, secondConstant;
bool varFirst1, varFirst2;
unsigned int varId;
const Token *varTok = NULL;
if (Token::Match(term1Tok, "%var% %any% %num%"))
{
varTok = term1Tok;
varId = varTok->varId();
if (!varId)
{
tok = Token::findmatch(endTok->next(), conditionPattern);
endTok = tok ? tok->next()->link() : NULL;
continue;
}
varFirst1 = true;
firstConstant = term1Tok->tokAt(2)->str();
}
else if (Token::Match(term1Tok, "%num% %any% %var%"))
{
varTok = term1Tok->tokAt(2);
varId = varTok->varId();
if (!varId)
{
tok = Token::findmatch(endTok->next(), conditionPattern);
endTok = tok ? tok->next()->link() : NULL;
continue;
}
varFirst1 = false;
firstConstant = term1Tok->str();
}
else
{
tok = Token::findmatch(endTok->next(), conditionPattern);
endTok = tok ? tok->next()->link() : NULL;
continue;
}
if (Token::Match(term2Tok, "%var% %any% %num%"))
{
const unsigned int varId2 = term2Tok->varId();
if (!varId2 || varId != varId2)
{
tok = Token::findmatch(endTok->next(), conditionPattern);
endTok = tok ? tok->next()->link() : NULL;
continue;
}
varFirst2 = true;
secondConstant = term2Tok->tokAt(2)->str();
variableTested = varId;
}
else if (Token::Match(term2Tok, "%num% %any% %var%"))
{
const unsigned int varId2 = term1Tok->tokAt(2)->varId();
if (!varId2 || varId != varId2)
{
tok = Token::findmatch(endTok->next(), conditionPattern);
endTok = tok ? tok->next()->link() : NULL;
continue;
}
varFirst2 = false;
secondConstant = term2Tok->str();
variableTested = varId;
}
else
{
tok = Token::findmatch(endTok->next(), conditionPattern);
endTok = tok ? tok->next()->link() : NULL;
continue;
}
if (variableTested == 0 || firstConstant.empty() || secondConstant.empty())
{
tok = Token::findmatch(endTok->next(), conditionPattern);
endTok = tok ? tok->next()->link() : NULL;
continue;
}
enum Position { First, Second, NA };
enum Relation { Equal, NotEqual, Less, LessEqual, More, MoreEqual };
enum LogicError { Exclusion, AlwaysTrue, AlwaysFalse, AlwaysFalseOr };
struct Condition
{
const char *before;
Position position1;
const char *op1TokStr;
const char *op2TokStr;
Position position2;
const char *op3TokStr;
const char *after;
Relation relation;
LogicError error;
} conditions[] =
{
{ "!!&&", NA, "!=", "||", NA, "!=", "!!&&", NotEqual, Exclusion }, // (x != 1) || (x != 3) <- always true
{ "(", NA, "==", "&&", NA, "==", ")", NotEqual, AlwaysFalseOr }, // (x == 1) && (x == 3) <- always false
{ "(", First, "<", "&&", First, ">", ")", LessEqual, AlwaysFalseOr }, // (x < 1) && (x > 3) <- always false
{ "(", First, ">", "&&", First, "<", ")", MoreEqual, AlwaysFalseOr }, // (x > 3) && (x < 1) <- always false
{ "(", Second, ">", "&&", First, ">", ")", LessEqual, AlwaysFalseOr }, // (1 > x) && (x > 3) <- always false
{ "(", First, ">", "&&", Second, ">", ")", MoreEqual, AlwaysFalseOr }, // (x > 3) && (1 > x) <- always false
{ "(", First, "<", "&&", Second, "<", ")", LessEqual, AlwaysFalseOr }, // (x < 1) && (3 < x) <- always false
{ "(", Second, "<", "&&", First, "<", ")", MoreEqual, AlwaysFalseOr }, // (3 < x) && (x < 1) <- always false
{ "(", Second, ">", "&&", Second, "<", ")", LessEqual, AlwaysFalseOr }, // (1 > x) && (3 < x) <- always false
{ "(", Second, "<", "&&", Second, ">", ")", MoreEqual, AlwaysFalseOr }, // (3 < x) && (1 > x) <- always false
{ "(", First , ">|>=", "||", First, "<|<=", ")", Less, Exclusion }, // (x > 3) || (x < 10) <- always true
{ "(", First , "<|<=", "||", First, ">|>=", ")", More, Exclusion }, // (x < 10) || (x > 3) <- always true
{ "(", Second, "<|<=", "||", First, "<|<=", ")", Less, Exclusion }, // (3 < x) || (x < 10) <- always true
{ "(", First, "<|<=", "||", Second, "<|<=", ")", More, Exclusion }, // (x < 10) || (3 < x) <- always true
{ "(", First, ">|>=", "||", Second, ">|>=", ")", Less, Exclusion }, // (x > 3) || (10 > x) <- always true
{ "(", Second, ">|>=", "||", First, ">|>=", ")", More, Exclusion }, // (10 > x) || (x > 3) <- always true
{ "(", Second, "<|<=", "||", Second, ">|<=", ")", Less, Exclusion }, // (3 < x) || (10 > x) <- always true
{ "(", Second, ">|>=", "||", Second, "<|<=", ")", More, Exclusion }, // (10 > x) || (3 < x) <- always true
{ "(", First, ">", "&&", NA, "!=", ")", More, AlwaysTrue }, // (x > 5) && (x != 1) <- second expression always true
{ "(", Second, "<", "&&", NA, "!=", ")", More, AlwaysTrue }, // (5 < x) && (x != 1) <- second expression always true
{ "(", First, ">", "&&", NA, "==", ")", More, AlwaysFalse }, // (x > 5) && (x == 1) <- second expression always false
{ "(", Second, "<", "&&", NA, "==", ")", More, AlwaysFalse }, // (5 < x) && (x == 1) <- second expression always false
};
for (unsigned int i = 0; i < (sizeof(conditions) / sizeof(conditions[0])); i++)
{
if (!((conditions[i].position1 == NA) || (((conditions[i].position1 == First) && varFirst1) || ((conditions[i].position1 == Second) && !varFirst1))))
continue;
if (!((conditions[i].position2 == NA) || (((conditions[i].position2 == First) && varFirst2) || ((conditions[i].position2 == Second) && !varFirst2))))
continue;
if (!Token::Match(op1Tok, conditions[i].op1TokStr))
continue;
if (!Token::Match(op2Tok, conditions[i].op2TokStr))
continue;
if (!Token::Match(op3Tok, conditions[i].op3TokStr))
continue;
if (!Token::Match(logicTok->previous(), conditions[i].before))
continue;
if (!Token::Match(nextTok, conditions[i].after))
continue;
if ((conditions[i].relation == Equal && MathLib::isEqual(firstConstant, secondConstant)) ||
(conditions[i].relation == NotEqual && MathLib::isNotEqual(firstConstant, secondConstant)) ||
(conditions[i].relation == Less && MathLib::isLess(firstConstant, secondConstant)) ||
(conditions[i].relation == LessEqual && MathLib::isLessEqual(firstConstant, secondConstant)) ||
(conditions[i].relation == More && MathLib::isGreater(firstConstant, secondConstant)) ||
(conditions[i].relation == MoreEqual && MathLib::isGreaterEqual(firstConstant, secondConstant)))
{
if (conditions[i].error == Exclusion || conditions[i].error == AlwaysFalseOr)
incorrectLogicOperatorError(term1Tok, conditions[i].error == Exclusion);
else
{
std::string text("When " + varTok->str() + " is greater than " + firstConstant + ", the comparison " +
varTok->str() + " " + conditions[i].op3TokStr + " " + secondConstant +
" is always " + (conditions[i].error == AlwaysTrue ? "true." : "false."));
secondAlwaysTrueFalseWhenFirstTrueError(term1Tok, text);
}
}
}
}
tok = Token::findmatch(endTok->next(), conditionPattern);
endTok = tok ? tok->next()->link() : NULL;
}
}
void CheckOther::incorrectLogicOperatorError(const Token *tok, bool always)
{
if (always)
reportError(tok, Severity::warning,
"incorrectLogicOperator", "Mutual exclusion over || always evaluates to true. Did you intend to use && instead?");
else
reportError(tok, Severity::warning,
"incorrectLogicOperator", "Expression always evaluates to false. Did you intend to use || instead?");
}
void CheckOther::secondAlwaysTrueFalseWhenFirstTrueError(const Token *tok, const std::string &truefalse)
{
reportError(tok, Severity::style, "secondAlwaysTrueFalseWhenFirstTrue", truefalse);
}
//---------------------------------------------------------------------------
// try {} catch (std::exception err) {} <- Should be "std::exception& err"
//---------------------------------------------------------------------------
void CheckOther::checkCatchExceptionByValue()
{
if (!_settings->isEnabled("style"))
return;
const char catchPattern[] = "} catch (";
const Token *tok = Token::findmatch(_tokenizer->tokens(), catchPattern);
const Token *endTok = tok ? tok->tokAt(2)->link() : NULL;
while (tok && endTok)
{
// Find a pass-by-value declaration in the catch(), excluding basic types
// e.g. catch (std::exception err)
const Token *tokType = Token::findmatch(tok, "%type% %var% )", endTok);
if (tokType && !tokType->isStandardType())
{
catchExceptionByValueError(tokType);
}
tok = Token::findmatch(endTok->next(), catchPattern);
endTok = tok ? tok->tokAt(2)->link() : NULL;
}
}
void CheckOther::catchExceptionByValueError(const Token *tok)
{
reportError(tok, Severity::style,
"catchExceptionByValue", "Exception should be caught by reference.\n"
"The exception is caught as a value. It could be caught "
"as a (const) reference which is usually recommended in C++.");
}
//---------------------------------------------------------------------------
// 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;
// Locate the third parameter of the function call..
int param = 1;
for (const Token *tok2 = tok->tokAt(2); tok2; tok2 = tok2->next())
{
if (tok2->str() == "(")
tok2 = tok2->link();
else if (tok2->str() == ")")
break;
else if (tok2->str() == ",")
{
++param;
if (param == 3)
{
if (Token::Match(tok2, ", %num% )"))
{
const MathLib::bigint radix = MathLib::toLongNumber(tok2->next()->str());
if (!(radix == 0 || (radix >= 2 && radix <= 36)))
{
dangerousUsageStrtolError(tok2);
}
}
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 && tok2->str() != ",")
tok2 = tok2->next();
if (!tok2)
continue;
// is any source buffer overlapping the target buffer?
int parlevel = 0;
while ((tok2 = tok2->next()) != NULL)
{
if (tok2->str() == "(")
++parlevel;
else if (tok2->str() == ")")
{
--parlevel;
if (parlevel < 0)
break;
}
else if (parlevel == 0 && Token::Match(tok2, ", %varid% [,)]", varid))
{
sprintfOverlappingDataError(tok2->next(), tok2->next()->str());
break;
}
}
}
}
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.'");
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
void CheckOther::invalidScanf()
{
if (!_settings->isEnabled("style"))
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
{
const Token *formatToken = 0;
if (Token::Match(tok, "scanf|vscanf ( %str% ,"))
formatToken = tok->tokAt(2);
else if (Token::Match(tok, "fscanf|vfscanf ( %var% , %str% ,"))
formatToken = tok->tokAt(4);
else
continue;
bool format = false;
// scan the string backwards, so we dont need to keep states
const std::string &formatstr(formatToken->str());
for (unsigned int i = 1; i < formatstr.length(); i++)
{
if (formatstr[i] == '%')
format = !format;
else if (!format)
continue;
else if (std::isdigit(formatstr[i]))
{
format = false;
}
else if (std::isalpha(formatstr[i]))
{
invalidScanfError(tok);
format = false;
}
}
}
}
void CheckOther::invalidScanfError(const Token *tok)
{
reportError(tok, Severity::warning,
"invalidscanf", "scanf without field width limits can crash with huge input data\n"
"scanf without field width limits can crash with huge input data. To fix this error "
"message add a field width specifier:\n"
" %s => %20s\n"
" %i => %3i\n"
"\n"
"Sample program that can crash:\n"
"\n"
"#include <stdio.h>\n"
"int main()\n"
"{\n"
" int a;\n"
" scanf(\"%i\", &a);\n"
" return 0;\n"
"}\n"
"\n"
"To make it crash:\n"
"perl -e 'print \"5\"x2100000' | ./a.out");
}
//---------------------------------------------------------------------------
// if (!x==3) <- Probably meant to be "x!=3"
//---------------------------------------------------------------------------
void CheckOther::checkComparisonOfBoolWithInt()
{
if (!_settings->isEnabled("style"))
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
{
if (Token::Match(tok, "( ! %var% ==|!= %num% )"))
{
const Token *numTok = tok->tokAt(4);
if (numTok && numTok->str() != "0")
{
comparisonOfBoolWithIntError(numTok, tok->strAt(2));
}
}
else if (Token::Match(tok, "( %num% ==|!= ! %var% )"))
{
const Token *numTok = tok->tokAt(1);
if (numTok && numTok->str() != "0")
{
comparisonOfBoolWithIntError(numTok, tok->strAt(4));
}
}
}
}
void CheckOther::comparisonOfBoolWithIntError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::warning, "comparisonOfBoolWithInt",
"Comparison of a boolean with a non-zero integer\n"
"The expression \"!" + varname + "\" is of type 'bool' but is compared against a non-zero 'int'.");
}
//---------------------------------------------------------------------------
// switch (x)
// {
// case 2:
// y = a;
// break;
// break; // <- Redundant break
// case 3:
// y = b;
// }
//---------------------------------------------------------------------------
void CheckOther::checkDuplicateBreak()
{
if (!_settings->isEnabled("style"))
return;
const char breakPattern[] = "break|continue ; break|continue ;";
// Find consecutive break or continue statements. e.g.:
// break; break;
const Token *tok = Token::findmatch(_tokenizer->tokens(), breakPattern);
while (tok)
{
duplicateBreakError(tok);
tok = Token::findmatch(tok->next(), breakPattern);
}
}
void CheckOther::duplicateBreakError(const Token *tok)
{
reportError(tok, Severity::style, "duplicateBreak",
"Consecutive break or continue statements are unnecessary\n"
"The second of the two statements can never be executed, and so should be removed\n");
}
//---------------------------------------------------------------------------
// Check for unsigned divisions
//---------------------------------------------------------------------------
void CheckOther::checkUnsignedDivision()
{
if (!_settings->isEnabled("style"))
return;
// Check for "ivar / uvar" and "uvar / ivar"
std::map<unsigned int, char> varsign;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
{
if (Token::Match(tok, "[{};(,] %type% %var% [;=,)]"))
{
if (tok->tokAt(1)->isUnsigned())
varsign[tok->tokAt(2)->varId()] = 'u';
else
varsign[tok->tokAt(2)->varId()] = 's';
}
else if (!Token::Match(tok, "[).]") && Token::Match(tok->next(), "%var% / %num%"))
{
if (tok->strAt(3)[0] == '-')
{
char sign1 = varsign[tok->tokAt(1)->varId()];
if (sign1 == 'u')
{
udivError(tok->next());
}
}
}
else if (Token::Match(tok, "(|[|=|%op% %num% / %var%"))
{
if (tok->strAt(1)[0] == '-')
{
char sign2 = varsign[tok->tokAt(3)->varId()];
if (sign2 == 'u')
{
udivError(tok->next());
}
}
}
}
}
void CheckOther::udivError(const Token *tok)
{
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()
{
const Token *tok = _tokenizer->tokens();
while (tok && ((tok = Token::findmatch(tok, "memset ( %var% , %num% , 0 )")) != NULL))
{
memsetZeroBytesError(tok, tok->strAt(2));
tok = tok->tokAt(8);
}
}
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("information"))
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;
// Walk through all tokens..
int indentlevel = 0;
for (const Token *tok = scope->classStart; tok; tok = tok->next())
{
// Skip function local class and struct declarations..
if ((tok->str() == "class") || (tok->str() == "struct") || (tok->str() == "union"))
{
for (const Token *tok2 = tok; tok2; tok2 = tok2->next())
{
if (tok2->str() == "{")
{
tok = tok2->link();
break;
}
if (Token::Match(tok2, "[,);]"))
{
break;
}
}
if (! tok)
break;
}
else if (tok->str() == "{")
{
++indentlevel;
}
else if (tok->str() == "}")
{
--indentlevel;
if (indentlevel == 0)
break;;
}
if (indentlevel > 0 && Token::Match(tok, "[{};]"))
{
// First token of statement..
const Token *tok1 = tok->next();
if (! tok1)
continue;
if ((tok1->str() == "return") ||
(tok1->str() == "throw") ||
(tok1->str() == "delete") ||
(tok1->str() == "goto") ||
(tok1->str() == "else"))
continue;
// Variable declaration?
if (Token::Match(tok1, "%type% %var% ; %var% = %num% ;"))
{
// Tokenizer modify "int i = 0;" to "int i; i = 0;",
// so to handle this situation we just skip
// initialization (see ticket #272).
const unsigned int firstVarId = tok1->next()->varId();
const unsigned int secondVarId = tok1->tokAt(3)->varId();
if (firstVarId > 0 && firstVarId == secondVarId)
{
lookupVar(tok1->tokAt(6), tok1->strAt(1));
}
}
else if (tok1->isStandardType() && Token::Match(tok1, "%type% %var% [;=]"))
{
lookupVar(tok1, tok1->strAt(1));
}
}
}
}
}
void CheckOther::lookupVar(const Token *tok1, const std::string &varname)
{
const Token *tok = tok1;
// 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
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, varname.c_str(), tok->link()))
{
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::simpleMatch(tok, (std::string("& ") + varname).c_str()))
{
return;
}
else if (tok->str() == varname)
{
if (indentlevel == 0)
return;
used1 = true;
if (for_or_while && !Token::simpleMatch(tok->next(), "="))
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 (Token::simpleMatch(tok->next(), "(") &&
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(tok1, varname);
}
void CheckOther::variableScopeError(const Token *tok, const std::string &varname)
{
reportError(tok,
Severity::information,
"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 (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
{
// 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, "[,(] const std :: string %var% [,)]"))
{
passedByValueError(tok, tok->strAt(5));
}
else if (Token::Match(tok, "[,(] const std :: %type% < %type% > %var% [,)]"))
{
passedByValueError(tok, tok->strAt(8));
}
else if (Token::Match(tok, "[,(] const std :: %type% < std :: %type% > %var% [,)]"))
{
passedByValueError(tok, tok->strAt(10));
}
else if (Token::Match(tok, "[,(] const std :: %type% < std :: %type% , std :: %type% > %var% [,)]"))
{
passedByValueError(tok, tok->strAt(14));
}
else if (Token::Match(tok, "[,(] const std :: %type% < %type% , std :: %type% > %var% [,)]"))
{
passedByValueError(tok, tok->strAt(12));
}
else if (Token::Match(tok, "[,(] const std :: %type% < std :: %type% , %type% > %var% [,)]"))
{
passedByValueError(tok, tok->strAt(12));
}
else if (Token::Match(tok, "[,(] const std :: %type% < %type% , %type% > %var% [,)]"))
{
passedByValueError(tok, tok->strAt(10));
}
else if (Token::Match(tok, "[,(] const %type% %var% [,)]"))
{
// Check if type is a struct or class.
if (symbolDatabase->isClassOrStruct(tok->strAt(2)))
{
passedByValueError(tok, tok->strAt(3));
}
}
}
}
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..
//---------------------------------------------------------------------------
void CheckOther::checkCharVariable()
{
if (!_settings->isEnabled("style"))
return;
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
{
// Declaring the variable..
if (Token::Match(tok, "[{};(,] const| char *| %var% [;=,)]") ||
Token::Match(tok, "[{};(,] const| char %var% ["))
{
// goto 'char' token
tok = tok->next();
if (tok->str() == "const")
tok = tok->next();
// Check for unsigned char
if (tok->isUnsigned())
continue;
// Set tok to point to the variable name
tok = tok->next();
const bool isPointer(tok->str() == "*" || tok->strAt(1) == "[");
if (tok->str() == "*")
tok = tok->next();
// Check usage of char variable..
int indentlevel = 0;
for (const Token *tok2 = tok->next(); tok2; tok2 = tok2->next())
{
if (tok2->str() == "{")
++indentlevel;
else if (tok2->str() == "}")
{
--indentlevel;
if (indentlevel <= 0)
break;
}
if (!isPointer)
{
std::string temp = "%var% [ " + tok->str() + " ]";
if ((tok2->str() != ".") && Token::Match(tok2->next(), temp.c_str()))
{
charArrayIndexError(tok2->next());
break;
}
}
if (Token::Match(tok2, "[;{}] %var% = %any% [&|] %any% ;"))
{
// is the char variable used in the calculation?
if (tok2->tokAt(3)->varId() != tok->varId() && tok2->tokAt(5)->varId() != tok->varId())
continue;
// it's ok with a bitwise and where the other operand is 0xff or less..
if (tok2->strAt(4) == "&")
{
if (tok2->tokAt(3)->isNumber() && MathLib::isGreater("0x100", tok2->strAt(3)))
continue;
if (tok2->tokAt(5)->isNumber() && MathLib::isGreater("0x100", tok2->strAt(5)))
continue;
}
// is the result stored in a short|int|long?
const Variable *var = symbolDatabase->getVariableFromVarId(tok2->next()->varId());
if (!(var && Token::Match(var->typeEndToken(), "short|int|long")))
continue;
// This is an error..
charBitOpError(tok2);
break;
}
if (isPointer && Token::Match(tok2, "[;{}] %var% = %any% [&|] ( * %varid% ) ;", tok->varId()))
{
// it's ok with a bitwise and where the other operand is 0xff or less..
if (tok2->strAt(4) == "&" && tok2->tokAt(3)->isNumber() && MathLib::isGreater("0x100", tok2->strAt(3)))
continue;
// is the result stored in a short|int|long?
const Variable *var = symbolDatabase->getVariableFromVarId(tok2->next()->varId());
if (!(var && Token::Match(var->typeEndToken(), "short|int|long")))
continue;
// This is an error..
charBitOpError(tok2);
break;
}
}
}
}
}
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% !!."))
{
// 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;
}
bool charVars[10000] = {0};
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
{
// Declaring char variable..
if (Token::Match(tok, "char|int|short %var% [;=]"))
{
unsigned int varid = tok->next()->varId();
if (varid > 0 && varid < 10000)
charVars[varid] = true;
}
//
else if (Token::Match(tok, "[=(] %str% + %any%"))
{
// char constant..
const std::string s = tok->strAt(3);
if (s[0] == '\'')
strPlusCharError(tok->next());
// char variable..
unsigned int varid = tok->tokAt(3)->varId();
if (varid > 0 && varid < 10000 && charVars[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->tokAt(4)->str()) &&
MathLib::toLongNumber(tok->tokAt(4)->str()) == 0L)
{
zerodivError(tok);
}
}
}
void CheckOther::zerodivError(const Token *tok)
{
reportError(tok, Severity::error, "zerodiv", "Division by zero");
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
void CheckOther::checkMathFunctions()
{
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
{
// case log(-2)
if (tok->varId() == 0 &&
Token::Match(tok, "log|log10 ( %num% )") &&
MathLib::isNegative(tok->tokAt(2)->str()) &&
MathLib::isInt(tok->tokAt(2)->str()) &&
MathLib::toLongNumber(tok->tokAt(2)->str()) <= 0)
{
mathfunctionCallError(tok);
}
// case log(-2.0)
else if (tok->varId() == 0 &&
Token::Match(tok, "log|log10 ( %num% )") &&
MathLib::isNegative(tok->tokAt(2)->str()) &&
MathLib::isFloat(tok->tokAt(2)->str()) &&
MathLib::toDoubleNumber(tok->tokAt(2)->str()) <= 0.)
{
mathfunctionCallError(tok);
}
// case log(0.0)
else if (tok->varId() == 0 &&
Token::Match(tok, "log|log10 ( %num% )") &&
!MathLib::isNegative(tok->tokAt(2)->str()) &&
MathLib::isFloat(tok->tokAt(2)->str()) &&
MathLib::toDoubleNumber(tok->tokAt(2)->str()) <= 0.)
{
mathfunctionCallError(tok);
}
// case log(0)
else if (tok->varId() == 0 &&
Token::Match(tok, "log|log10 ( %num% )") &&
!MathLib::isNegative(tok->tokAt(2)->str()) &&
MathLib::isInt(tok->tokAt(2)->str()) &&
MathLib::toLongNumber(tok->tokAt(2)->str()) <= 0)
{
mathfunctionCallError(tok);
}
// acos( x ), asin( x ) where x is defined for intervall [-1,+1], but not beyound
else if (tok->varId() == 0 &&
Token::Match(tok, "acos|asin ( %num% )") &&
std::fabs(MathLib::toDoubleNumber(tok->tokAt(2)->str())) > 1.0)
{
mathfunctionCallError(tok);
}
// sqrt( x ): if x is negative the result is undefined
else if (tok->varId() == 0 &&
Token::Match(tok, "sqrt|sqrtf|sqrtl ( %num% )") &&
MathLib::isNegative(tok->tokAt(2)->str()))
{
mathfunctionCallError(tok);
}
// atan2 ( x , y): x and y can not be zero, because this is mathematically not defined
else if (tok->varId() == 0 &&
Token::Match(tok, "atan2 ( %num% , %num% )") &&
MathLib::isNullValue(tok->tokAt(2)->str()) &&
MathLib::isNullValue(tok->tokAt(4)->str()))
{
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 (tok->varId() == 0 &&
Token::Match(tok, "fmod ( %num% , %num% )") &&
MathLib::isNullValue(tok->tokAt(4)->str()))
{
mathfunctionCallError(tok, 2);
}
// pow ( x , y) If x is zero, and y is negative --> division by zero
else if (tok->varId() == 0 &&
Token::Match(tok, "pow ( %num% , %num% )") &&
MathLib::isNullValue(tok->tokAt(2)->str()) &&
MathLib::isNegative(tok->tokAt(4)->str()))
{
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->tokAt(2)->str() + " to " + tok->str() + "() leads to undefined result");
else if (numParam == 2)
reportError(tok, Severity::error, "wrongmathcall", "Passing value " + tok->tokAt(2)->str() + " and " + tok->tokAt(4)->str() + " to " + tok->str() + "() leads to undefined result");
}
else
reportError(tok, Severity::error, "wrongmathcall", "Passing value " " to " "() leads to undefined result");
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
/** 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->tokAt(2)->link();
}
// 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;
}
bool CheckOther::code_is_c() const
{
const std::string fname = _tokenizer->getFiles()->at(0);
const size_t position = fname.rfind(".");
if (position != std::string::npos)
{
const std::string ext = fname.substr(position);
if (ext == ".c" || ext == ".C")
return true;
}
return false;
}
void CheckOther::checkMisusedScopedObject()
{
// Skip this check for .c files
if (code_is_c())
{
return;
}
const SymbolDatabase * const 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;
unsigned int depth = 0;
for (const Token *tok = scope->classStart; tok; tok = tok->next())
{
if (tok->str() == "{")
{
++depth;
}
else if (tok->str() == "}")
{
--depth;
if (depth == 0)
break;
}
if (Token::Match(tok, "[;{}] %var% (")
&& Token::simpleMatch(tok->tokAt(2)->link(), ") ;")
&& 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()
{
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
{
if (Token::Match(tok, ". substr ( %any% , %num% ) ==|!= %str%"))
{
size_t clen = MathLib::toLongNumber(tok->tokAt(5)->str());
size_t slen = Token::getStrLength(tok->tokAt(8));
if (clen != slen)
{
incorrectStringCompareError(tok->next(), "substr", tok->tokAt(8)->str(), tok->tokAt(5)->str());
}
}
if (Token::Match(tok, "%str% ==|!= %var% . substr ( %any% , %num% )"))
{
size_t clen = MathLib::toLongNumber(tok->tokAt(8)->str());
size_t slen = Token::getStrLength(tok);
if (clen != slen)
{
incorrectStringCompareError(tok->next(), "substr", tok->str(), tok->tokAt(8)->str());
}
}
}
}
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 + ").");
}
//-----------------------------------------------------------------------------
// check for duplicate expressions in if statements
// if (a) { } else if (a) { }
//-----------------------------------------------------------------------------
static const std::string stringifyTokens(const Token *start, const Token *end)
{
const Token *tok = start;
std::string stringified;
if (tok->isUnsigned())
stringified.append("unsigned ");
else if (tok->isSigned())
stringified.append("signed ");
if (tok->isLong())
stringified.append("long ");
stringified.append(tok->str());
while (tok && tok->next() && tok != end)
{
if (tok->isUnsigned())
stringified.append("unsigned ");
else if (tok->isSigned())
stringified.append("signed ");
if (tok->isLong())
stringified.append("long ");
tok = tok->next();
stringified.append(" ");
stringified.append(tok->str());
}
return stringified;
}
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 (Token::Match(tok, "++|--"))
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();
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 if (...) and else if (...) statements
for (const Token *tok = scope->classStart; tok && tok != scope->classStart->link(); tok = tok->next())
{
if (Token::simpleMatch(tok, "if (") && tok->strAt(-1) != "else" &&
Token::simpleMatch(tok->next()->link(), ") {"))
{
std::map<std::string, const Token*> expressionMap;
// get the expression from the token stream
std::string expression = stringifyTokens(tok->tokAt(2), tok->next()->link()->previous());
// save the expression and its location
expressionMap.insert(std::make_pair(expression, tok));
// find the next else if (...) statement
const Token *tok1 = tok->next()->link()->next()->link();
// check all the else if (...) statements
while (Token::simpleMatch(tok1, "} else if (") &&
Token::simpleMatch(tok1->tokAt(3)->link(), ") {"))
{
// get the expression from the token stream
expression = stringifyTokens(tok1->tokAt(4), tok1->tokAt(3)->link()->previous());
// 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->tokAt(3)->link()->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->tokAt(3)->link()->next()->link();
}
tok = tok->next()->link()->next();
}
}
}
}
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;
if (!_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 if (..) else
for (const Token *tok = scope->classStart; tok && tok != scope->classStart->link(); tok = tok->next())
{
if (Token::simpleMatch(tok, "if (") && tok->strAt(-1) != "else" &&
Token::simpleMatch(tok->next()->link(), ") {") &&
Token::simpleMatch(tok->next()->link()->next()->link(), "} else {"))
{
// save if branch code
std::string branch1 = stringifyTokens(tok->next()->link()->tokAt(2), tok->next()->link()->next()->link()->previous());
// find else branch
const Token *tok1 = tok->next()->link()->next()->link();
// save else branch code
std::string branch2 = stringifyTokens(tok1->tokAt(3), tok1->tokAt(2)->link()->previous());
// check for duplicates
if (branch1 == branch2)
duplicateBranchError(tok, tok1->tokAt(2));
tok = tok->next()->link()->next();
}
}
}
}
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.");
}
//---------------------------------------------------------------------------
// 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;
for (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->classStart->link(); tok = tok->next())
{
if (Token::Match(tok, "(|&&|%oror% %var% &&|%oror%|==|!=|<=|>=|<|>|-|%or% %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;
}
}
duplicateExpressionError(tok->next(), tok->tokAt(3), tok->strAt(2));
}
else if (Token::Match(tok, "(|&&|%oror% %var% . %var% &&|%oror%|==|!=|<=|>=|<|>|-|%or% %var% . %var% )|&&|%oror%") &&
tok->strAt(1) == tok->strAt(5) && tok->strAt(3) == tok->strAt(7))
{
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") && !_settings->isEnabled("performance"))
return;
const char pattern1[] = "strcmp|stricmp|strcmpi|strcasecmp|wcscmp ( %str% , %str% )";
const char pattern2[] = "QString :: compare ( %str% , %str% )";
const Token *tok = _tokenizer->tokens();
while (tok && (tok = Token::findmatch(tok, pattern1)) != NULL)
{
alwaysTrueFalseStringCompareError(tok, tok->strAt(2), tok->strAt(4));
tok = tok->tokAt(5);
}
tok = _tokenizer->tokens();
while (tok && (tok = Token::findmatch(tok, pattern2)) != NULL)
{
alwaysTrueFalseStringCompareError(tok, tok->strAt(4), tok->strAt(6));
tok = tok->tokAt(7);
}
}
void CheckOther::alwaysTrueFalseStringCompareError(const Token *tok, const std::string& str1, const std::string& str2)
{
const 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) + "..");
if (str1 == str2)
{
reportError(tok, Severity::warning, "staticStringCompare",
"Comparison of always identical static strings.\n"
"The compared strings, '" + string1 + "' and '" + string2 + "', are always identical. "
"If the purpose is to compare these two strings, the comparison is unnecessary. "
"If the strings are supposed to be different, then there is a bug somewhere.");
}
else if (_settings->isEnabled("performance"))
{
reportError(tok, Severity::performance, "staticStringCompare",
"Unnecessary comparison of static strings.\n"
"The compared strings, '" + string1 + "' and '" + string2 + "', are static and always different. "
"If the purpose is to compare these two strings, the comparison is unnecessary.");
}
}
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
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 ("))
{
unsigned int parlevel = 0;
for (const Token *tok2 = tok->tokAt(2); tok2; tok2 = tok2->next())
{
if (tok2->str() == "(")
++parlevel;
else if (tok2->str() == ")")
{
if (parlevel <= 1)
break;
--parlevel;
}
else if (Token::Match(tok2, "+|/"))
{
sizeofCalculationError(tok2);
break;
}
}
}
}
}
void CheckOther::sizeofCalculationError(const Token *tok)
{
reportError(tok, Severity::warning,
"sizeofCalculation", "Found calculation inside sizeof()");
}
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
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->nameToken()->strAt(-1) == "*")
assignBoolToPointerError(tok->next());
}
}
}
void CheckOther::assignBoolToPointerError(const Token *tok)
{
reportError(tok, Severity::error, "assignBoolToPointer",
"Assigning bool value to pointer (converting bool value to address)");
}
//---------------------------------------------------------------------------
// Check testing sign of unsigned variables.
//---------------------------------------------------------------------------
void CheckOther::checkSignOfUnsignedVariable()
{
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)
{
// 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->classStart->link(); tok = tok->next())
{
if (Token::Match(tok, "( %var% <|<= 0 )") && tok->next()->varId())
{
const Variable * var = symbolDatabase->getVariableFromVarId(tok->next()->varId());
if (var && var->typeEndToken()->isUnsigned())
unsignedLessThanZeroError(tok->next(), tok->next()->str());
}
else if (Token::Match(tok, "( 0 > %var% )") && tok->tokAt(3)->varId())
{
const Variable * var = symbolDatabase->getVariableFromVarId(tok->tokAt(3)->varId());
if (var && var->typeEndToken()->isUnsigned())
unsignedLessThanZeroError(tok->tokAt(3), tok->strAt(3));
}
else if (Token::Match(tok, "( 0 <= %var% )") && tok->tokAt(3)->varId())
{
const Variable * var = symbolDatabase->getVariableFromVarId(tok->tokAt(3)->varId());
if (var && var->typeEndToken()->isUnsigned())
unsignedPositiveError(tok->tokAt(3), tok->strAt(3));
}
}
}
}
void CheckOther::unsignedLessThanZeroError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::style, "unsignedLessThanZero",
"Checking if unsigned variable '" + varname + "' is less than zero.\n"
"An unsigned variable will never be negative so it is either pointless or "
"an error to check if it is.");
}
void CheckOther::unsignedPositiveError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::style, "unsignedPositive",
"Checking if unsigned variable '" + varname + "' is positive is always true.\n"
"An unsigned variable will always be positive so it is either pointless or "
"an error to check if it is.");
}
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