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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()
//---------------------------------------------------------------------------
// Register this check class (by creating a static instance of it)
namespace
{
CheckOther instance;
}
//---------------------------------------------------------------------------
void CheckOther::warningOldStylePointerCast()
{
if (!_settings->_checkCodingStyle ||
(_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);
}
}
//---------------------------------------------------------------------------
// 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);
}
}
//---------------------------------------------------------------------------
// 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";
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);
}
}
//---------------------------------------------------------------------------
// int x = 1;
// x = x; // <- redundant assignment to self
//
// int y = y; // <- redundant initialization to self
//---------------------------------------------------------------------------
void CheckOther::checkSelfAssignment()
{
if (!_settings->_checkCodingStyle)
return;
const char selfAssignmentPattern[] = "%var% = %var% ;|=|)";
const Token *tok = Token::findmatch(_tokenizer->tokens(), selfAssignmentPattern);
while (tok)
{
if (tok->varId() && tok->varId() == tok->tokAt(2)->varId())
{
selfAssignmentError(tok, tok->str());
}
tok = Token::findmatch(tok->next(), selfAssignmentPattern);
}
}
//---------------------------------------------------------------------------
// int a = 1;
// assert(a = 2); // <- assert should not have a side-effect
//---------------------------------------------------------------------------
void CheckOther::checkAssignmentInAssert()
{
if (!_settings->_checkCodingStyle)
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;
}
}
//---------------------------------------------------------------------------
// if ((x != 1) || (x != 3)) // <- always true
//---------------------------------------------------------------------------
void CheckOther::checkIncorrectLogicOperator()
{
if (!_settings->_checkCodingStyle)
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 OR'd terms, with or without parenthesis
// e.g. if (x != 3 || x != 4)
const Token *logicTok = NULL, *term1Tok = NULL, *term2Tok = NULL;
if (NULL != (logicTok = Token::findmatch(tok, "( %any% != %any% ) %oror% ( %any% != %any% ) !!&&", endTok)))
{
term1Tok = logicTok->next();
term2Tok = logicTok->tokAt(7);
}
else if (NULL != (logicTok = Token::findmatch(tok, "%any% != %any% %oror% %any% != %any% !!&&", endTok)))
{
term1Tok = logicTok;
term2Tok = logicTok->tokAt(4);
}
// The terms must not be AND'd with anything, to prevent false positives
if (logicTok && (logicTok->strAt(-1) != "&&"))
{
// Find the common variable and the two different-valued constants
unsigned int variableTested = 0;
std::string firstConstant, secondConstant;
if (Token::Match(term1Tok, "%var% != %num%"))
{
const unsigned int varId = term1Tok->varId();
if (!varId)
{
tok = Token::findmatch(endTok->next(), conditionPattern);
endTok = tok ? tok->next()->link() : NULL;
continue;
}
firstConstant = term1Tok->tokAt(2)->str();
if (Token::Match(term2Tok, "%varid% != %num%", varId))
{
variableTested = varId;
secondConstant = term2Tok->tokAt(2)->str();
}
else if (Token::Match(term2Tok, "%num% != %varid%", varId))
{
variableTested = varId;
secondConstant = term2Tok->str();
}
}
else if (Token::Match(term1Tok, "%num% != %var%"))
{
const unsigned int varId = term1Tok->tokAt(2)->varId();
firstConstant = term1Tok->str();
if (Token::Match(term2Tok, "%varid% != %num%", varId))
{
variableTested = varId;
secondConstant = term2Tok->tokAt(2)->str();
}
else if (Token::Match(term2Tok, "%num% != %varid%", varId))
{
variableTested = varId;
secondConstant = term2Tok->str();
}
}
// If there is a common variable tested for inequality against
// either of two different-valued constants, then the expression
// will always evaluate to true and the || probably should be an &&
if (variableTested != 0 &&
!firstConstant.empty() &&
!secondConstant.empty() &&
firstConstant != secondConstant)
{
incorrectLogicOperatorError(term1Tok);
}
}
tok = Token::findmatch(endTok->next(), conditionPattern);
endTok = tok ? tok->next()->link() : NULL;
}
}
//---------------------------------------------------------------------------
// try {} catch (std::exception err) {} <- Should be "std::exception& err"
//---------------------------------------------------------------------------
void CheckOther::checkCatchExceptionByValue()
{
if (!_settings->_checkCodingStyle)
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;
}
}
//---------------------------------------------------------------------------
// 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();
// 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::invalidScanf()
{
if (!_settings->_checkCodingStyle)
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");
}
//---------------------------------------------------------------------------
// Check for unsigned divisions
//---------------------------------------------------------------------------
void CheckOther::checkUnsignedDivision()
{
if (!_settings->_checkCodingStyle)
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, "[([=*/+-,] %num% / %var%"))
{
if (tok->strAt(1)[0] == '-')
{
char sign2 = varsign[tok->tokAt(3)->varId()];
if (sign2 == 'u')
{
udivError(tok->next());
}
}
}
}
}
//---------------------------------------------------------------------------
// 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);
}
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
// Usage of function variables
//---------------------------------------------------------------------------
static bool isOp(const Token *tok)
{
return bool(tok &&
(tok->str() == "&&" ||
tok->str() == "||" ||
tok->str() == "==" ||
tok->str() == "!=" ||
tok->str() == "<" ||
tok->str() == "<=" ||
tok->str() == ">" ||
tok->str() == ">=" ||
tok->str() == "<<" ||
Token::Match(tok, "[+-*/%&!~|^,[])?:]")));
}
/**
* @brief This class is used to capture the control flow within a function.
*/
class Scope
{
public:
Scope() : _token(NULL), _parent(NULL) { }
Scope(const Token *token, Scope *parent_) : _token(token), _parent(parent_) { }
~Scope();
Scope *parent()
{
return _parent;
}
Scope *addChild(const Token *token);
void remove(Scope *scope);
private:
const Token *_token;
Scope *_parent;
std::list<Scope *> _children;
};
Scope::~Scope()
{
while (!_children.empty())
{
delete *_children.begin();
_children.pop_front();
}
}
Scope *Scope::addChild(const Token *token)
{
Scope *temp = new Scope(token, this);
_children.push_back(temp);
return temp;
}
void Scope::remove(Scope *scope)
{
std::list<Scope *>::iterator it;
for (it = _children.begin(); it != _children.end(); ++it)
{
if (*it == scope)
{
delete *it;
_children.erase(it);
break;
}
}
}
/**
* @brief This class is used create a list of variables within a function.
*/
class Variables
{
public:
enum VariableType { standard, array, pointer, reference, pointerArray, referenceArray, pointerPointer };
/** Store information about variable usage */
class VariableUsage
{
public:
VariableUsage(const Token *name = 0,
VariableType type = standard,
Scope *scope = NULL,
bool read = false,
bool write = false,
bool modified = false,
bool allocateMemory = false) :
_name(name),
_type(type),
_scope(scope),
_read(read),
_write(write),
_modified(modified),
_allocateMemory(allocateMemory)
{
}
/** variable is used.. set both read+write */
void use()
{
_read = true;
_write = true;
}
/** is variable unused? */
bool unused() const
{
return (_read == false && _write == false);
}
const Token *_name;
VariableType _type;
Scope *_scope;
bool _read;
bool _write;
bool _modified; // read/modify/write
bool _allocateMemory;
std::set<unsigned int> _aliases;
std::set<Scope *> _assignments;
};
typedef std::map<unsigned int, VariableUsage> VariableMap;
void clear()
{
_varUsage.clear();
}
VariableMap &varUsage()
{
return _varUsage;
}
void addVar(const Token *name, VariableType type, Scope *scope, bool write_);
void allocateMemory(unsigned int varid);
void read(unsigned int varid);
void readAliases(unsigned int varid);
void readAll(unsigned int varid);
void write(unsigned int varid);
void writeAliases(unsigned int varid);
void writeAll(unsigned int varid);
void use(unsigned int varid);
void modified(unsigned int varid);
VariableUsage *find(unsigned int varid);
void alias(unsigned int varid1, unsigned int varid2, bool replace);
void erase(unsigned int varid)
{
_varUsage.erase(varid);
}
void eraseAliases(unsigned int varid);
void eraseAll(unsigned int varid);
void clearAliases(unsigned int varid);
private:
VariableMap _varUsage;
};
/**
* Alias the 2 given variables. Either replace the existing aliases if
* they exist or merge them. You would replace an existing alias when this
* assignment is in the same scope as the previous assignment. You might
* merge the aliases when this assignment is in a different scope from the
* previous assignment depending on the relationship of the 2 scopes.
*/
void Variables::alias(unsigned int varid1, unsigned int varid2, bool replace)
{
VariableUsage *var1 = find(varid1);
VariableUsage *var2 = find(varid2);
// alias to self
if (varid1 == varid2)
{
if (var1)
var1->use();
return;
}
std::set<unsigned int>::iterator i;
if (replace)
{
// remove var1 from all aliases
for (i = var1->_aliases.begin(); i != var1->_aliases.end(); ++i)
{
VariableUsage *temp = find(*i);
if (temp)
temp->_aliases.erase(var1->_name->varId());
}
// remove all aliases from var1
var1->_aliases.clear();
}
// var1 gets all var2s aliases
for (i = var2->_aliases.begin(); i != var2->_aliases.end(); ++i)
{
if (*i != varid1)
var1->_aliases.insert(*i);
}
// var2 is an alias of var1
var2->_aliases.insert(varid1);
var1->_aliases.insert(varid2);
if (var2->_type == Variables::pointer)
var2->_read = true;
}
void Variables::clearAliases(unsigned int varid)
{
VariableUsage *usage = find(varid);
if (usage)
{
// remove usage from all aliases
std::set<unsigned int>::iterator i;
for (i = usage->_aliases.begin(); i != usage->_aliases.end(); ++i)
{
VariableUsage *temp = find(*i);
if (temp)
temp->_aliases.erase(usage->_name->varId());
}
// remove all aliases from usage
usage->_aliases.clear();
}
}
void Variables::eraseAliases(unsigned int varid)
{
VariableUsage *usage = find(varid);
if (usage)
{
std::set<unsigned int>::iterator aliases;
for (aliases = usage->_aliases.begin(); aliases != usage->_aliases.end(); ++aliases)
erase(*aliases);
}
}
void Variables::eraseAll(unsigned int varid)
{
eraseAliases(varid);
erase(varid);
}
void Variables::addVar(const Token *name,
VariableType type,
Scope *scope,
bool write_)
{
if (name->varId() > 0)
_varUsage.insert(std::make_pair(name->varId(), VariableUsage(name, type, scope, false, write_, false)));
}
void Variables::allocateMemory(unsigned int varid)
{
VariableUsage *usage = find(varid);
if (usage)
usage->_allocateMemory = true;
}
void Variables::read(unsigned int varid)
{
VariableUsage *usage = find(varid);
if (usage)
usage->_read = true;
}
void Variables::readAliases(unsigned int varid)
{
VariableUsage *usage = find(varid);
if (usage)
{
std::set<unsigned int>::iterator aliases;
for (aliases = usage->_aliases.begin(); aliases != usage->_aliases.end(); ++aliases)
{
VariableUsage *aliased = find(*aliases);
if (aliased)
aliased->_read = true;
}
}
}
void Variables::readAll(unsigned int varid)
{
VariableUsage *usage = find(varid);
if (usage)
{
usage->_read = true;
std::set<unsigned int>::iterator aliases;
for (aliases = usage->_aliases.begin(); aliases != usage->_aliases.end(); ++aliases)
{
VariableUsage *aliased = find(*aliases);
if (aliased)
aliased->_read = true;
}
}
}
void Variables::write(unsigned int varid)
{
VariableUsage *usage = find(varid);
if (usage)
usage->_write = true;
}
void Variables::writeAliases(unsigned int varid)
{
VariableUsage *usage = find(varid);
if (usage)
{
std::set<unsigned int>::iterator aliases;
for (aliases = usage->_aliases.begin(); aliases != usage->_aliases.end(); ++aliases)
{
VariableUsage *aliased = find(*aliases);
if (aliased)
aliased->_write = true;
}
}
}
void Variables::writeAll(unsigned int varid)
{
VariableUsage *usage = find(varid);
if (usage)
{
usage->_write = true;
std::set<unsigned int>::iterator aliases;
for (aliases = usage->_aliases.begin(); aliases != usage->_aliases.end(); ++aliases)
{
VariableUsage *aliased = find(*aliases);
if (aliased)
aliased->_write = true;
}
}
}
void Variables::use(unsigned int varid)
{
VariableUsage *usage = find(varid);
if (usage)
{
usage->use();
std::set<unsigned int>::iterator aliases;
for (aliases = usage->_aliases.begin(); aliases != usage->_aliases.end(); ++aliases)
{
VariableUsage *aliased = find(*aliases);
if (aliased)
aliased->use();
}
}
}
void Variables::modified(unsigned int varid)
{
VariableUsage *usage = find(varid);
if (usage)
{
usage->_modified = true;
std::set<unsigned int>::iterator aliases;
for (aliases = usage->_aliases.begin(); aliases != usage->_aliases.end(); ++aliases)
{
VariableUsage *aliased = find(*aliases);
if (aliased)
aliased->_modified = true;
}
}
}
Variables::VariableUsage *Variables::find(unsigned int varid)
{
if (varid)
{
VariableMap::iterator i = _varUsage.find(varid);
if (i != _varUsage.end())
return &i->second;
}
return 0;
}
static int doAssignment(Variables &variables, const Token *tok, bool dereference, Scope *scope)
{
int next = 0;
// a = a + b;
if (Token::Match(tok, "%var% = %var% !!;") && tok->str() == tok->strAt(2))
{
return 2;
}
// check for aliased variable
const unsigned int varid1 = tok->varId();
Variables::VariableUsage *var1 = variables.find(varid1);
if (var1)
{
Variables::VariableUsage *var2 = 0;
int start = 1;
// search for '='
while (tok->tokAt(start)->str() != "=")
start++;
start++;
if (Token::Match(tok->tokAt(start), "&| %var%") ||
Token::Match(tok->tokAt(start), "( const| struct|union| %type% *| ) &| %var%") ||
Token::Match(tok->tokAt(start), "( const| struct|union| %type% *| ) ( &| %var%") ||
Token::Match(tok->tokAt(start), "%any% < const| struct|union| %type% *| > ( &| %var%"))
{
unsigned char offset = 0;
unsigned int varid2;
bool addressOf = false;
if (Token::Match(tok->tokAt(start), "%var% ."))
variables.use(tok->tokAt(start)->varId()); // use = read + write
// check for C style cast
if (tok->tokAt(start)->str() == "(")
{
if (tok->tokAt(start + 1)->str() == "const")
offset++;
if (Token::Match(tok->tokAt(start + 1 + offset), "struct|union"))
offset++;
if (tok->tokAt(start + 2 + offset)->str() == "*")
offset++;
if (tok->tokAt(start + 3 + offset)->str() == "&")
{
addressOf = true;
next = start + 4 + offset;
}
else if (tok->tokAt(start + 3 + offset)->str() == "(")
{
if (tok->tokAt(start + 4 + offset)->str() == "&")
{
addressOf = true;
next = start + 5 + offset;
}
else
next = start + 4 + offset;
}
else
next = start + 3 + offset;
}
// check for C++ style cast
else if (tok->tokAt(start)->str().find("cast") != std::string::npos &&
tok->tokAt(start + 1)->str() == "<")
{
if (tok->tokAt(start + 2)->str() == "const")
offset++;
if (Token::Match(tok->tokAt(start + 2 + offset), "struct|union"))
offset++;
if (tok->tokAt(start + 3 + offset)->str() == "*")
offset++;
if (tok->tokAt(start + 5 + offset)->str() == "&")
{
addressOf = true;
next = start + 6 + offset;
}
else
next = start + 5 + offset;
}
// check for var ? ...
else if (Token::Match(tok->tokAt(start), "%var% ?"))
{
next = start;
}
// no cast
else
{
if (tok->tokAt(start)->str() == "&")
{
addressOf = true;
next = start + 1;
}
else if (tok->tokAt(start)->str() == "new")
return 0;
else
next = start;
}
// check if variable is local
varid2 = tok->tokAt(next)->varId();
var2 = variables.find(varid2);
if (var2) // local variable (alias or read it)
{
if (var1->_type == Variables::pointer)
{
if (dereference)
variables.read(varid2);
else
{
if (addressOf ||
var2->_type == Variables::array ||
var2->_type == Variables::pointer)
{
bool replace = true;
// check if variable declared in same scope
if (scope == var1->_scope)
replace = true;
// not in same scope as declaration
else
{
std::set<Scope *>::iterator assignment;
// check for an assignment in this scope
assignment = var1->_assignments.find(scope);
// no other assignment in this scope
if (assignment == var1->_assignments.end())
{
// nothing to replace
if (var1->_assignments.empty())
replace = false;
// this variable has previous assignments
else
{
/**
* @todo determine if existing aliases should be replaced or merged
*/
replace = false;
}
}
// assignment in this scope
else
{
// replace when only one other assignment
if (var1->_assignments.size() == 1)
replace = true;
// otherwise, merge them
else
replace = false;
}
}
variables.alias(varid1, varid2, replace);
}
else if (tok->tokAt(next + 1)->str() == "?")
{
if (var2->_type == Variables::reference)
variables.readAliases(varid2);
else
variables.read(varid2);
}
}
}
else if (var1->_type == Variables::reference)
{
variables.alias(varid1, varid2, true);
}
else
{
if (var2->_type == Variables::pointer && tok->tokAt(next + 1)->str() == "[")
variables.readAliases(varid2);
variables.read(varid2);
}
}
else // not a local variable (or an unsupported local variable)
{
if (var1->_type == Variables::pointer && !dereference)
{
// check if variable declaration is in this scope
if (var1->_scope == scope)
variables.clearAliases(varid1);
else
{
std::set<Scope *>::iterator assignment;
// check for an assignment in this scope
assignment = var1->_assignments.find(scope);
// no other assignment in this scope
if (assignment == var1->_assignments.end())
{
/**
* @todo determine if existing aliases should be discarded
*/
}
// this assignment replaces the last assignment in this scope
else
{
// aliased variables in a larger scope are not supported
// remove all aliases
variables.clearAliases(varid1);
}
}
}
}
}
var1->_assignments.insert(scope);
}
// check for alias to struct member
// char c[10]; a.b = c;
else if (Token::Match(tok->tokAt(-2), "%var% ."))
{
if (Token::Match(tok->tokAt(2), "%var%"))
{
unsigned int varid2 = tok->tokAt(2)->varId();
Variables::VariableUsage *var2 = variables.find(varid2);
// struct member aliased to local variable
if (var2 && (var2->_type == Variables::array ||
var2->_type == Variables::pointer))
{
// erase aliased variable and all variables that alias it
// to prevent false positives
variables.eraseAll(varid2);
}
}
}
return next;
}
static bool nextIsStandardType(const Token *tok)
{
tok = tok->next();
if (tok->str() == "static")
tok = tok->next();
return tok->isStandardType();
}
static bool nextIsStandardTypeOrVoid(const Token *tok)
{
tok = tok->next();
if (tok->str() == "static")
tok = tok->next();
if (tok->str() == "const")
tok = tok->next();
return tok->isStandardType() || tok->str() == "void";
}
void CheckOther::functionVariableUsage()
{
if (!_settings->_checkCodingStyle)
return;
// Parse all executing scopes..
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
std::list<SymbolDatabase::SpaceInfo *>::const_iterator i;
for (i = symbolDatabase->spaceInfoList.begin(); i != symbolDatabase->spaceInfoList.end(); ++i)
{
const SymbolDatabase::SpaceInfo *info = *i;
// only check functions
if (info->type != SymbolDatabase::SpaceInfo::Function)
continue;
// First token for the current scope..
const Token *const tok1 = info->classStart;
// varId, usage {read, write, modified}
Variables variables;
// scopes
Scope scopes;
Scope *scope = &scopes;
unsigned int indentlevel = 0;
for (const Token *tok = tok1; tok; tok = tok->next())
{
if (tok->str() == "{")
{
// replace the head node when found
if (indentlevel == 0)
scopes = Scope(tok, NULL);
// add the new scope
else
scope = scope->addChild(tok);
++indentlevel;
}
else if (tok->str() == "}")
{
--indentlevel;
scope = scope->parent();
if (indentlevel == 0)
break;
}
else if (Token::Match(tok, "struct|union|class {") ||
Token::Match(tok, "struct|union|class %type% {|:"))
{
while (tok->str() != "{")
tok = tok->next();
tok = tok->link();
if (! tok)
break;
}
if (Token::Match(tok, "[;{}] asm ( ) ;"))
{
variables.clear();
break;
}
// standard type declaration with possible initialization
// int i; int j = 0; static int k;
if (Token::Match(tok, "[;{}] static| %type% %var% ;|=") &&
nextIsStandardType(tok))
{
tok = tok->next();
if (tok->str() == "static")
tok = tok->next();
variables.addVar(tok->next(), Variables::standard, scope,
tok->tokAt(2)->str() == "=" ||
tok->previous()->str() == "static");
tok = tok->next();
}
// standard type declaration and initialization using constructor
// int i(0); static int j(0);
else if (Token::Match(tok, "[;{}] static| %type% %var% ( %any% ) ;") &&
nextIsStandardType(tok))
{
tok = tok->next();
if (tok->str() == "static")
tok = tok->next();
variables.addVar(tok->next(), Variables::standard, scope, true);
// check if a local variable is used to initialize this variable
if (tok->tokAt(3)->varId() > 0)
variables.readAll(tok->tokAt(3)->varId());
tok = tok->tokAt(4);
}
// standard type declaration of array of with possible initialization
// int i[10]; int j[2] = { 0, 1 }; static int k[2] = { 2, 3 };
else if (Token::Match(tok, "[;{}] static| const| %type% *| %var% [ %any% ] ;|=") &&
nextIsStandardType(tok))
{
bool isStatic = false;
tok = tok->next();
if (tok->str() == "static")
{
tok = tok->next();
isStatic = true;
}
if (tok->str() == "const")
tok = tok->next();
if (tok->str() != "return" && tok->str() != "throw")
{
bool isPointer = bool(tok->strAt(1) == "*");
const Token * const nametok = tok->tokAt(isPointer ? 2 : 1);
variables.addVar(nametok, isPointer ? Variables::pointerArray : Variables::array, scope,
nametok->tokAt(4)->str() == "=" || isStatic);
// check for reading array size from local variable
if (nametok->tokAt(2)->varId() != 0)
variables.read(nametok->tokAt(2)->varId());
// look at initializers
if (Token::Match(nametok->tokAt(4), "= {"))
{
tok = nametok->tokAt(6);
while (tok->str() != "}")
{
if (Token::Match(tok, "%var%"))
variables.read(tok->varId());
tok = tok->next();
}
}
else
tok = nametok->tokAt(3);
}
}
// pointer or reference declaration with possible initialization
// int * i; int * j = 0; static int * k = 0;
else if (Token::Match(tok, "[;{}] static| const| %type% *|& %var% ;|="))
{
bool isStatic = false;
tok = tok->next();
if (tok->str() == "static")
{
tok = tok->next();
isStatic = true;
}
if (tok->str() == "const")
tok = tok->next();
if (tok->strAt(1) == "::")
tok = tok->tokAt(2);
if (tok->str() != "return" && tok->str() != "throw")
{
Variables::VariableType type;
if (tok->next()->str() == "*")
type = Variables::pointer;
else
type = Variables::reference;
bool written = tok->tokAt(3)->str() == "=";
variables.addVar(tok->tokAt(2), type, scope, written || isStatic);
int offset = 0;
// check for assignment
if (written)
offset = doAssignment(variables, tok->tokAt(2), false, scope);
tok = tok->tokAt(2 + offset);
}
}
// pointer to pointer declaration with possible initialization
// int ** i; int ** j = 0; static int ** k = 0;
else if (Token::Match(tok, "[;{}] static| const| %type% * * %var% ;|="))
{
bool isStatic = false;
tok = tok->next();
if (tok->str() == "static")
{
tok = tok->next();
isStatic = true;
}
if (tok->str() == "const")
tok = tok->next();
if (tok->str() != "return")
{
bool written = tok->tokAt(4)->str() == "=";
variables.addVar(tok->tokAt(3), Variables::pointerPointer, scope, written || isStatic);
int offset = 0;
// check for assignment
if (written)
offset = doAssignment(variables, tok->tokAt(3), false, scope);
tok = tok->tokAt(3 + offset);
}
}
// pointer or reference of struct or union declaration with possible initialization
// struct s * i; struct s * j = 0; static struct s * k = 0;
else if (Token::Match(tok, "[;{}] static| const| struct|union %type% *|& %var% ;|="))
{
Variables::VariableType type;
bool isStatic = false;
tok = tok->next();
if (tok->str() == "static")
{
tok = tok->next();
isStatic = true;
}
if (tok->str() == "const")
tok = tok->next();
if (tok->strAt(2) == "*")
type = Variables::pointer;
else
type = Variables::reference;
const bool written = tok->strAt(4) == "=";
variables.addVar(tok->tokAt(3), type, scope, written || isStatic);
int offset = 0;
// check for assignment
if (written)
offset = doAssignment(variables, tok->tokAt(3), false, scope);
tok = tok->tokAt(3 + offset);
}
// pointer or reference declaration with initialization using constructor
// int * i(j); int * k(i); static int * l(i);
else if (Token::Match(tok, "[;{}] static| const| %type% &|* %var% ( %any% ) ;") &&
nextIsStandardTypeOrVoid(tok))
{
Variables::VariableType type;
tok = tok->next();
if (tok->str() == "static")
tok = tok->next();
if (tok->str() == "const")
tok = tok->next();
if (tok->next()->str() == "*")
type = Variables::pointer;
else
type = Variables::reference;
unsigned int varid = 0;
// check for aliased variable
if (Token::Match(tok->tokAt(4), "%var%"))
varid = tok->tokAt(4)->varId();
variables.addVar(tok->tokAt(2), type, scope, true);
// check if a local variable is used to initialize this variable
if (varid > 0)
{
Variables::VariableUsage *var = variables.find(varid);
if (type == Variables::pointer)
{
variables.use(tok->tokAt(4)->varId());
if (var && (var->_type == Variables::array ||
var->_type == Variables::pointer))
var->_aliases.insert(tok->varId());
}
else
{
variables.readAll(tok->tokAt(4)->varId());
if (var)
var->_aliases.insert(tok->varId());
}
}
tok = tok->tokAt(5);
}
// array of pointer or reference declaration with possible initialization
// int * p[10]; int * q[10] = { 0 }; static int * * r[10] = { 0 };
else if (Token::Match(tok, "[;{}] static| const| %type% *|& %var% [ %any% ] ;|="))
{
bool isStatic = false;
tok = tok->next();
if (tok->str() == "static")
{
tok = tok->next();
isStatic = true;
}
if (tok->str() == "const")
tok = tok->next();
if (tok->str() != "return")
{
variables.addVar(tok->tokAt(2),
tok->next()->str() == "*" ? Variables::pointerArray : Variables::referenceArray, scope,
tok->tokAt(6)->str() == "=" || isStatic);
// check for reading array size from local variable
if (tok->tokAt(4)->varId() != 0)
variables.read(tok->tokAt(4)->varId());
tok = tok->tokAt(5);
}
}
// array of pointer or reference of struct or union declaration with possible initialization
// struct S * p[10]; struct T * q[10] = { 0 }; static struct S * r[10] = { 0 };
else if (Token::Match(tok, "[;{}] static| const| struct|union %type% *|& %var% [ %any% ] ;|="))
{
bool isStatic = false;
tok = tok->next();
if (tok->str() == "static")
{
tok = tok->next();
isStatic = true;
}
if (tok->str() == "const")
tok = tok->next();
variables.addVar(tok->tokAt(3),
tok->tokAt(2)->str() == "*" ? Variables::pointerArray : Variables::referenceArray, scope,
tok->tokAt(7)->str() == "=" || isStatic);
// check for reading array size from local variable
if (tok->tokAt(5)->varId() != 0)
variables.read(tok->tokAt(5)->varId());
tok = tok->tokAt(6);
}
// Freeing memory (not considered "using" the pointer if it was also allocated in this function)
else if (Token::Match(tok, "free|g_free|kfree|vfree ( %var% )") ||
Token::Match(tok, "delete %var% ;") ||
Token::Match(tok, "delete [ ] %var% ;"))
{
unsigned int varid = 0;
if (tok->str() != "delete")
{
varid = tok->tokAt(2)->varId();
tok = tok->tokAt(3);
}
else if (tok->strAt(1) == "[")
{
varid = tok->tokAt(3)->varId();
tok = tok->tokAt(4);
}
else
{
varid = tok->next()->varId();
tok = tok->tokAt(2);
}
Variables::VariableUsage *var = variables.find(varid);
if (var && !var->_allocateMemory)
{
variables.readAll(varid);
}
}
else if (Token::Match(tok, "return|throw %var%"))
variables.readAll(tok->next()->varId());
// assignment
else if (Token::Match(tok, "*| (| ++|--| %var% ++|--| )| =") ||
Token::Match(tok, "*| ( const| %type% *| ) %var% ="))
{
bool dereference = false;
bool pre = false;
bool post = false;
if (tok->str() == "*")
{
dereference = true;
tok = tok->next();
}
if (Token::Match(tok, "( const| %type% *| ) %var% ="))
tok = tok->link()->next();
else if (tok->str() == "(")
tok = tok->next();
if (Token::Match(tok, "++|--"))
{
pre = true;
tok = tok->next();
}
if (Token::Match(tok->next(), "++|--"))
post = true;
const unsigned int varid1 = tok->varId();
const Token *start = tok;
tok = tok->tokAt(doAssignment(variables, tok, dereference, scope));
if (pre || post)
variables.use(varid1);
if (dereference)
{
variables.writeAliases(varid1);
variables.read(varid1);
}
else
{
Variables::VariableUsage *var = variables.find(varid1);
if (var && var->_type == Variables::reference)
{
variables.writeAliases(varid1);
variables.read(varid1);
}
// Consider allocating memory separately because allocating/freeing alone does not constitute using the variable
else if (var && var->_type == Variables::pointer &&
Token::Match(start, "%var% = new|malloc|calloc|g_malloc|kmalloc|vmalloc"))
{
bool allocate = true;
if (start->strAt(2) == "new")
{
// is it a user defined type?
if (!start->tokAt(3)->isStandardType())
{
// lookup the type
const SymbolDatabase::SpaceInfo *type = symbolDatabase->findVarType(info, start->tokAt(3));
// unknown type?
if (!type)
allocate = false;
// has default constructor or
// has members with unknown type or default constructor
else if (type->needInitialization == SymbolDatabase::SpaceInfo::False)
allocate = false;
}
}
if (allocate)
variables.allocateMemory(varid1);
else
variables.write(varid1);
}
else if (varid1 && Token::Match(tok, "%varid% .", varid1))
{
variables.use(varid1);
}
else
{
variables.write(varid1);
}
Variables::VariableUsage *var2 = variables.find(tok->varId());
if (var2)
{
if (var2->_type == Variables::reference)
{
variables.writeAliases(tok->varId());
variables.read(tok->varId());
}
else if (tok->varId() != varid1 && Token::Match(tok, "%var% ."))
variables.use(tok->varId());
else if (tok->varId() != varid1 &&
var2->_type == Variables::standard &&
tok->strAt(-1) != "&")
variables.use(tok->varId());
}
}
const Token *equal = tok->next();
if (Token::Match(tok->next(), "[ %any% ]"))
equal = tok->tokAt(4);
// checked for chained assignments
if (tok != start && equal->str() == "=")
{
Variables::VariableUsage *var = variables.find(tok->varId());
if (var && var->_type != Variables::reference)
var->_read = true;
tok = tok->previous();
}
}
// assignment
else if (Token::Match(tok, "%var% [") && Token::Match(tok->next()->link(), "] ="))
{
unsigned int varid = tok->varId();
const Variables::VariableUsage *var = variables.find(varid);
if (var)
{
// Consider allocating memory separately because allocating/freeing alone does not constitute using the variable
if (var->_type == Variables::pointer &&
Token::Match(tok->next()->link(), "] = new|malloc|calloc|g_malloc|kmalloc|vmalloc"))
{
variables.allocateMemory(varid);
}
else if (var->_type == Variables::pointer || var->_type == Variables::reference)
{
variables.read(varid);
variables.writeAliases(varid);
}
else
variables.writeAll(varid);
}
}
else if (Token::Match(tok, ">>|& %var%"))
variables.use(tok->next()->varId()); // use = read + write
else if (Token::Match(tok, "[;{}] %var% >>"))
variables.use(tok->next()->varId()); // use = read + write
// function parameter
else if (Token::Match(tok, "[(,] %var% ["))
variables.use(tok->next()->varId()); // use = read + write
else if (Token::Match(tok, "[(,] %var% [,)]") && tok->previous()->str() != "*")
variables.use(tok->next()->varId()); // use = read + write
else if (Token::Match(tok, "[(,] (") &&
Token::Match(tok->next()->link(), ") %var% [,)]"))
variables.use(tok->next()->link()->next()->varId()); // use = read + write
// function
else if (Token::Match(tok, " %var% ("))
{
variables.read(tok->varId());
if (Token::Match(tok->tokAt(2), "%var% ="))
variables.read(tok->tokAt(2)->varId());
}
else if (Token::Match(tok, " %var% ."))
variables.use(tok->varId()); // use = read + write
else if ((Token::Match(tok, "[(=&!]") || isOp(tok)) &&
(Token::Match(tok->next(), "%var%") && !Token::Match(tok->next(), "true|false|new")))
variables.readAll(tok->next()->varId());
else if (Token::Match(tok, "%var%") && (tok->next()->str() == ")" || isOp(tok->next())))
variables.readAll(tok->varId());
else if (Token::Match(tok, "; %var% ;"))
variables.readAll(tok->next()->varId());
if (Token::Match(tok, "++|-- %var%"))
{
if (tok->strAt(-1) != ";")
variables.use(tok->next()->varId());
else
variables.modified(tok->next()->varId());
}
else if (Token::Match(tok, "%var% ++|--"))
{
if (tok->strAt(-1) != ";")
variables.use(tok->varId());
else
variables.modified(tok->varId());
}
}
// Check usage of all variables in the current scope..
Variables::VariableMap::const_iterator it;
for (it = variables.varUsage().begin(); it != variables.varUsage().end(); ++it)
{
const Variables::VariableUsage &usage = it->second;
const std::string &varname = usage._name->str();
// variable has been marked as unused so ignore it
if (usage._name->isUnused())
continue;
// skip things that are only partially implemented to prevent false positives
if (usage._type == Variables::pointerPointer ||
usage._type == Variables::pointerArray ||
usage._type == Variables::referenceArray)
continue;
// variable has had memory allocated for it, but hasn't done
// anything with that memory other than, perhaps, freeing it
if (usage.unused() && !usage._modified && usage._allocateMemory)
allocatedButUnusedVariableError(usage._name, varname);
// variable has not been written, read, or modified
else if (usage.unused() && !usage._modified)
unusedVariableError(usage._name, varname);
// variable has not been written but has been modified
else if (usage._modified & !usage._write)
unassignedVariableError(usage._name, varname);
// variable has been written but not read
else if (!usage._read && !usage._modified)
unreadVariableError(usage._name, varname);
// variable has been read but not written
else if (!usage._write && !usage._allocateMemory)
unassignedVariableError(usage._name, varname);
}
}
}
void CheckOther::unusedVariableError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::style, "unusedVariable", "Unused variable: " + varname);
}
void CheckOther::allocatedButUnusedVariableError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::style, "unusedAllocatedMemory", "Variable '" + varname + "' is allocated memory that is never used");
}
void CheckOther::unreadVariableError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::style, "unreadVariable", "Variable '" + varname + "' is assigned a value that is never used");
}
void CheckOther::unassignedVariableError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::style, "unassignedVariable", "Variable '" + varname + "' is not assigned a value");
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
// Check scope of variables..
//---------------------------------------------------------------------------
void CheckOther::checkVariableScope()
{
if (!_settings->isEnabled("information"))
return;
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
std::list<SymbolDatabase::SpaceInfo *>::const_iterator i;
for (i = symbolDatabase->spaceInfoList.begin(); i != symbolDatabase->spaceInfoList.end(); ++i)
{
const SymbolDatabase::SpaceInfo *info = *i;
// only check functions
if (info->type != SymbolDatabase::SpaceInfo::Function)
continue;
// Walk through all tokens..
int indentlevel = 0;
for (const Token *tok = info->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() == "{")
{
++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;
}
if (Token::simpleMatch(tok, "do {"))
for_or_while = true;
// possible unexpanded macro hiding for/while..
if (Token::Match(tok->previous(), "[;{}] %type% {"))
{
bool upper = true;
for (unsigned int i = 0; i < tok->str().length(); ++i)
{
if (!std::isupper(tok->str()[i]))
upper = false;
}
for_or_while |= upper;
}
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);
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
// Check for constant function parameters
//---------------------------------------------------------------------------
void CheckOther::checkConstantFunctionParameter()
{
if (!_settings->_checkCodingStyle)
return;
const SymbolDatabase * const symbolDatabase = _tokenizer->getSymbolDatabase();
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
{
if (Token::Match(tok, "[,(] const std :: %type% %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));
}
}
}
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
// Check that all struct members are used
//---------------------------------------------------------------------------
void CheckOther::checkStructMemberUsage()
{
if (!_settings->_checkCodingStyle)
return;
std::string structname;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
{
if (tok->fileIndex() != 0)
continue;
if (Token::Match(tok, "struct|union %type% {"))
{
structname.clear();
if (Token::simpleMatch(tok->previous(), "extern"))
continue;
if ((!tok->previous() || Token::simpleMatch(tok->previous(), ";")) && Token::Match(tok->tokAt(2)->link(), ("} ; " + tok->strAt(1) + " %var% ;").c_str()))
continue;
structname = tok->strAt(1);
// Bail out if struct/union contain any functions
for (const Token *tok2 = tok->tokAt(2); tok2; tok2 = tok2->next())
{
if (tok2->str() == "(")
{
structname.clear();
break;
}
if (tok2->str() == "}")
break;
}
// bail out if struct is inherited
if (!structname.empty() && Token::findmatch(tok, (",|private|protected|public " + structname).c_str()))
structname.clear();
// Bail out if some data is casted to struct..
const std::string s("( struct| " + tok->next()->str() + " * ) & %var% [");
if (Token::findmatch(tok, s.c_str()))
structname.clear();
// Try to prevent false positives when struct members are not used directly.
if (Token::findmatch(tok, (structname + " *").c_str()))
structname.clear();
else if (Token::findmatch(tok, (structname + " %type% *").c_str()))
structname = "";
}
if (tok->str() == "}")
structname.clear();
if (!structname.empty() && Token::Match(tok, "[{;]"))
{
// Declaring struct variable..
std::string varname;
// declaring a POD variable?
if (!tok->next()->isStandardType())
continue;
if (Token::Match(tok->next(), "%type% %var% [;[]"))
varname = tok->strAt(2);
else if (Token::Match(tok->next(), "%type% %type% %var% [;[]"))
varname = tok->strAt(3);
else if (Token::Match(tok->next(), "%type% * %var% [;[]"))
varname = tok->strAt(3);
else if (Token::Match(tok->next(), "%type% %type% * %var% [;[]"))
varname = tok->strAt(4);
else
continue;
// Check if the struct variable is used anywhere in the file
const std::string usagePattern(". " + varname);
bool used = false;
for (const Token *tok2 = _tokenizer->tokens(); tok2; tok2 = tok2->next())
{
if (Token::simpleMatch(tok2, usagePattern.c_str()))
{
used = true;
break;
}
}
if (! used)
{
unusedStructMemberError(tok->next(), structname, varname);
}
}
}
}
//---------------------------------------------------------------------------
// Check usage of char variables..
//---------------------------------------------------------------------------
void CheckOther::checkCharVariable()
{
if (!_settings->_checkCodingStyle)
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
{
// Declaring the variable..
if (Token::Match(tok, "[{};(,] char %var% [;=,)]"))
{
// Check for unsigned char
if (tok->tokAt(1)->isUnsigned())
continue;
// Set tok to point to the variable name
tok = tok->tokAt(2);
if (tok->str() == "char")
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;
}
else if (tok2->str() == "return")
continue;
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 (std::string(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?
if (!Token::findmatch(_tokenizer->tokens(), "short|int|long %varid%", tok2->next()->varId()))
continue;
// This is an error..
charBitOpError(tok2);
break;
}
}
}
}
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
// Incomplete statement..
//---------------------------------------------------------------------------
void CheckOther::checkIncompleteStatement()
{
if (!_settings->_checkCodingStyle)
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
{
if (tok->str() == "(")
tok = tok->link();
else if (Token::simpleMatch(tok, "= {"))
tok = tok->next()->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");
}
}
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
// 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] == '\'')
strPlusChar(tok->next());
// char variable..
unsigned int varid = tok->tokAt(3)->varId();
if (varid > 0 && varid < 10000 && charVars[varid])
strPlusChar(tok->next());
}
}
}
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::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 ( %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::checkMisusedScopedObject()
{
// Skip this check for .c files
{
const std::string fname = _tokenizer->getFiles()->at(0);
const std::string ext = fname.substr(fname.rfind("."));
if (ext == ".c" || ext == ".C")
return;
}
const SymbolDatabase * const symbolDatabase = _tokenizer->getSymbolDatabase();
std::list<SymbolDatabase::SpaceInfo *>::const_iterator i;
for (i = symbolDatabase->spaceInfoList.begin(); i != symbolDatabase->spaceInfoList.end(); ++i)
{
const SymbolDatabase::SpaceInfo *info = *i;
// only check functions
if (info->type != SymbolDatabase::SpaceInfo::Function)
continue;
unsigned int depth = 0;
for (const Token *tok = info->classStart; tok; tok = tok->next())
{
if (tok->str() == "{")
{
++depth;
}
else if (tok->str() == "}")
{
--depth;
if (depth == 0)
break;
}
if (Token::Match(tok, "[;{}] %var% (")
&& Token::Match(tok->tokAt(2)->link(), ") ;")
&& symbolDatabase->isClassOrStruct(tok->next()->str())
)
{
tok = tok->next();
misusedScopeObjectError(tok, tok->str());
tok = tok->next();
}
}
}
}
void CheckOther::cstyleCastError(const Token *tok)
{
reportError(tok, Severity::style, "cstyleCast", "C-style pointer casting");
}
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 parameter and destination in "
"and destination buffer 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::udivError(const Token *tok)
{
reportError(tok, Severity::error, "udivError", "Unsigned division. The result will be wrong.");
}
void CheckOther::unusedStructMemberError(const Token *tok, const std::string &structname, const std::string &varname)
{
reportError(tok, Severity::style, "unusedStructMember", "struct or union member '" + structname + "::" + varname + "' is never used");
}
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++.");
}
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");
}
void CheckOther::charArrayIndexError(const Token *tok)
{
reportError(tok, Severity::warning, "charArrayIndex", "Warning - using char variable as array index");
}
void CheckOther::charBitOpError(const Token *tok)
{
reportError(tok, Severity::warning, "charBitOp", "Warning - using char variable in bit operation");
}
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.");
}
void CheckOther::conditionAlwaysTrueFalse(const Token *tok, const std::string &truefalse)
{
reportError(tok, Severity::style, "conditionAlwaysTrueFalse", "Condition is always " + truefalse);
}
void CheckOther::strPlusChar(const Token *tok)
{
reportError(tok, Severity::error, "strPlusChar", "Unusual pointer arithmetic");
}
void CheckOther::zerodivError(const Token *tok)
{
reportError(tok, Severity::error, "zerodiv", "Division by zero");
}
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");
}
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::sizeofsizeof()
{
if (!_settings->_checkCodingStyle)
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
{
if (Token::simpleMatch(tok, "sizeof sizeof"))
sizeofsizeofError(tok);
}
}
void CheckOther::sizeofsizeofError(const Token *tok)
{
reportError(tok, Severity::warning,
"sizeofsizeof", "Calling sizeof for 'sizeof'.\n"
"This is 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->_checkCodingStyle)
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::redundantAssignmentInSwitchError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::warning,
"redundantAssignInSwitch", "Redundant assignment of \"" + varname + "\" in switch");
}
void CheckOther::selfAssignmentError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::warning,
"selfAssignment", "Redundant assignment of \"" + varname + "\" to itself");
}
void CheckOther::assignmentInAssertError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::warning,
"assignmentInAssert", "Assert statement modifies '" + varname + "'.\n"
"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.");
}
void CheckOther::incorrectLogicOperatorError(const Token *tok)
{
reportError(tok, Severity::warning,
"incorrectLogicOperator", "Mutual exclusion over || always evaluates to true. Did you intend to use && instead?");
}
void CheckOther::misusedScopeObjectError(const Token *tok, const std::string& varname)
{
reportError(tok, Severity::error,
"unusedScopedObject", "instance of \"" + varname + "\" object destroyed immediately");
}
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++.");
}
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);
}
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