cppcheck/lib/astutils.cpp

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/*
* Cppcheck - A tool for static C/C++ code analysis
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* Copyright (C) 2007-2016 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 "astutils.h"
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#include "symboldatabase.h"
#include "token.h"
#include "tokenize.h"
#include <set>
static bool astIsCharWithSign(const Token *tok, ValueType::Sign sign)
{
if (!tok)
return false;
const ValueType *valueType = tok->valueType();
if (!valueType)
return false;
return valueType->type == ValueType::Type::CHAR && valueType->pointer == 0U && valueType->sign == sign;
}
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bool astIsSignedChar(const Token *tok)
{
return astIsCharWithSign(tok, ValueType::Sign::SIGNED);
}
bool astIsUnknownSignChar(const Token *tok)
{
return astIsCharWithSign(tok, ValueType::Sign::UNKNOWN_SIGN);
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}
bool astIsIntegral(const Token *tok, bool unknown)
{
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const ValueType *vt = tok ? tok->valueType() : nullptr;
if (!vt)
return unknown;
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return vt->isIntegral() && vt->pointer == 0U;
}
bool astIsFloat(const Token *tok, bool unknown)
{
const ValueType *vt = tok ? tok->valueType() : nullptr;
if (!vt)
return unknown;
return vt->type >= ValueType::Type::FLOAT && vt->pointer == 0U;
}
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bool astIsBool(const Token *tok)
{
return tok && (tok->isBoolean() || (tok->valueType() && tok->valueType()->type == ValueType::Type::BOOL && !tok->valueType()->pointer));
}
std::string astCanonicalType(const Token *expr)
{
if (!expr)
return "";
if (expr->variable()) {
const Variable *var = expr->variable();
std::string ret;
for (const Token *type = var->typeStartToken(); Token::Match(type,"%name%|::") && type != var->nameToken(); type = type->next()) {
if (!Token::Match(type, "const|static"))
ret += type->str();
}
return ret;
}
// TODO: handle expressions
return "";
}
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static bool match(const Token *tok, const std::string &rhs)
{
if (tok->str() == rhs)
return true;
if (tok->isName() && !tok->varId() && tok->values.size() == 1U && tok->values.front().isKnown() && MathLib::toString(tok->values.front().intvalue) == rhs)
return true;
return false;
}
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const Token * astIsVariableComparison(const Token *tok, const std::string &comp, const std::string &rhs, const Token **vartok)
{
if (!tok)
return nullptr;
const Token *ret = nullptr;
if (tok->isComparisonOp()) {
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if (tok->astOperand1() && match(tok->astOperand1(), rhs)) {
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// Invert comparator
std::string s = tok->str();
if (s[0] == '>')
s[0] = '<';
else if (s[0] == '<')
s[0] = '>';
if (s == comp) {
ret = tok->astOperand2();
}
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} else if (tok->str() == comp && tok->astOperand2() && match(tok->astOperand2(), rhs)) {
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ret = tok->astOperand1();
}
} else if (comp == "!=" && rhs == std::string("0")) {
ret = tok;
} else if (comp == "==" && rhs == std::string("0")) {
if (tok->str() == "!")
ret = tok->astOperand1();
}
while (ret && ret->str() == ".")
ret = ret->astOperand2();
if (ret && ret->varId() == 0U)
ret = nullptr;
if (vartok)
*vartok = ret;
return ret;
}
bool isSameExpression(bool cpp, bool macro, const Token *tok1, const Token *tok2, const std::set<std::string> &constFunctions)
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{
if (tok1 == nullptr && tok2 == nullptr)
return true;
if (tok1 == nullptr || tok2 == nullptr)
return false;
if (cpp) {
if (tok1->str() == "." && tok1->astOperand1() && tok1->astOperand1()->str() == "this")
tok1 = tok1->astOperand2();
if (tok2->str() == "." && tok2->astOperand1() && tok2->astOperand1()->str() == "this")
tok2 = tok2->astOperand2();
}
if (tok1->varId() != tok2->varId() || tok1->str() != tok2->str() || tok1->originalName() != tok2->originalName()) {
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if ((Token::Match(tok1,"<|>") && Token::Match(tok2,"<|>")) ||
(Token::Match(tok1,"<=|>=") && Token::Match(tok2,"<=|>="))) {
return isSameExpression(cpp, macro, tok1->astOperand1(), tok2->astOperand2(), constFunctions) &&
isSameExpression(cpp, macro, tok1->astOperand2(), tok2->astOperand1(), constFunctions);
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}
return false;
}
if (macro && (tok1->isExpandedMacro() || tok2->isExpandedMacro()))
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return false;
if (tok1->isName() && tok1->next()->str() == "(" && tok1->str() != "sizeof") {
if (!tok1->function() && !Token::Match(tok1->previous(), ".|::") && constFunctions.find(tok1->str()) == constFunctions.end() && !tok1->isAttributeConst() && !tok1->isAttributePure())
return false;
else if (tok1->function() && !tok1->function()->isConst() && !tok1->function()->isAttributeConst() && !tok1->function()->isAttributePure())
return false;
}
// templates/casts
if ((Token::Match(tok1, "%name% <") && tok1->next()->link()) ||
(Token::Match(tok2, "%name% <") && tok2->next()->link())) {
// non-const template function that is not a dynamic_cast => return false
if (Token::simpleMatch(tok1->next()->link(), "> (") &&
!(tok1->function() && tok1->function()->isConst()) &&
tok1->str() != "dynamic_cast")
return false;
// some template/cast stuff.. check that the template arguments are same
const Token *t1 = tok1->next();
const Token *t2 = tok2->next();
const Token *end1 = t1->link();
const Token *end2 = t2->link();
while (t1 && t2 && t1 != end1 && t2 != end2) {
if (t1->str() != t2->str())
return false;
t1 = t1->next();
t2 = t2->next();
}
if (t1 != end1 || t2 != end2)
return false;
}
if (tok1->tokType() == Token::eIncDecOp || tok1->isAssignmentOp())
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return false;
// bailout when we see ({..})
if (tok1->str() == "{")
return false;
if (tok1->str() == "(" && tok1->previous() && !tok1->previous()->isName()) { // cast => assert that the casts are equal
const Token *t1 = tok1->next();
const Token *t2 = tok2->next();
while (t1 && t2 &&
t1->str() == t2->str() &&
t1->isLong() == t2->isLong() &&
t1->isUnsigned() == t2->isUnsigned() &&
t1->isSigned() == t2->isSigned() &&
(t1->isName() || t1->str() == "*")) {
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t1 = t1->next();
t2 = t2->next();
}
if (!t1 || !t2 || t1->str() != ")" || t2->str() != ")")
return false;
}
bool noncommutativeEquals =
isSameExpression(cpp, macro, tok1->astOperand1(), tok2->astOperand1(), constFunctions);
noncommutativeEquals = noncommutativeEquals &&
isSameExpression(cpp, macro, tok1->astOperand2(), tok2->astOperand2(), constFunctions);
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if (noncommutativeEquals)
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return true;
const bool commutative = tok1->astOperand1() && tok1->astOperand2() && Token::Match(tok1, "%or%|%oror%|+|*|&|&&|^|==|!=");
bool commutativeEquals = commutative &&
isSameExpression(cpp, macro, tok1->astOperand2(), tok2->astOperand1(), constFunctions);
commutativeEquals = commutativeEquals &&
isSameExpression(cpp, macro, tok1->astOperand1(), tok2->astOperand2(), constFunctions);
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// in c++, "a"+b might be different to b+"a"
if (cpp && commutativeEquals && tok1->str() == "+" &&
(tok1->astOperand1()->tokType() == Token::eString || tok1->astOperand2()->tokType() == Token::eString)) {
const Token * const other = tok1->astOperand1()->tokType() != Token::eString ? tok1->astOperand1() : tok1->astOperand2();
return other && astIsIntegral(other,false);
}
return commutativeEquals;
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}
bool isOppositeCond(bool isNot, bool cpp, const Token * const cond1, const Token * const cond2, const std::set<std::string> &constFunctions)
{
if (!cond1 || !cond2)
return false;
if (cond1->str() == "!") {
if (cond2->str() == "!=") {
if (cond2->astOperand1() && cond2->astOperand1()->str() == "0")
return isSameExpression(cpp, true, cond1->astOperand1(), cond2->astOperand2(), constFunctions);
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if (cond2->astOperand2() && cond2->astOperand2()->str() == "0")
return isSameExpression(cpp, true, cond1->astOperand1(), cond2->astOperand1(), constFunctions);
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}
return isSameExpression(cpp, true, cond1->astOperand1(), cond2, constFunctions);
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}
if (cond2->str() == "!")
return isOppositeCond(isNot, cpp, cond2, cond1, constFunctions);
if (!cond1->isComparisonOp() || !cond2->isComparisonOp())
return false;
const std::string &comp1 = cond1->str();
// condition found .. get comparator
std::string comp2;
if (isSameExpression(cpp, true, cond1->astOperand1(), cond2->astOperand1(), constFunctions) &&
isSameExpression(cpp, true, cond1->astOperand2(), cond2->astOperand2(), constFunctions)) {
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comp2 = cond2->str();
} else if (isSameExpression(cpp, true, cond1->astOperand1(), cond2->astOperand2(), constFunctions) &&
isSameExpression(cpp, true, cond1->astOperand2(), cond2->astOperand1(), constFunctions)) {
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comp2 = cond2->str();
if (comp2[0] == '>')
comp2[0] = '<';
else if (comp2[0] == '<')
comp2[0] = '>';
}
// is condition opposite?
return ((comp1 == "==" && comp2 == "!=") ||
(comp1 == "!=" && comp2 == "==") ||
(comp1 == "<" && comp2 == ">=") ||
(comp1 == "<=" && comp2 == ">") ||
(comp1 == ">" && comp2 == "<=") ||
(comp1 == ">=" && comp2 == "<") ||
(!isNot && ((comp1 == "<" && comp2 == ">") ||
(comp1 == ">" && comp2 == "<"))));
}
bool isConstExpression(const Token *tok, const std::set<std::string> &constFunctions)
{
if (!tok)
return true;
if (tok->isName() && tok->next()->str() == "(") {
if (!tok->function() && !Token::Match(tok->previous(), ".|::") && constFunctions.find(tok->str()) == constFunctions.end())
return false;
else if (tok->function() && !tok->function()->isConst())
return false;
}
if (tok->tokType() == Token::eIncDecOp)
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return false;
// bailout when we see ({..})
if (tok->str() == "{")
return false;
return isConstExpression(tok->astOperand1(),constFunctions) && isConstExpression(tok->astOperand2(),constFunctions);
}
bool isWithoutSideEffects(bool cpp, const Token* tok)
{
if (!cpp)
return true;
while (tok && tok->astOperand2() && tok->astOperand2()->str() != "(")
tok = tok->astOperand2();
if (tok && tok->varId()) {
const Variable* var = tok->variable();
return var && (!var->isClass() || var->isPointer() || var->isStlType());
}
return true;
}
bool isReturnScope(const Token * const endToken)
{
if (!endToken || endToken->str() != "}")
return false;
const Token *prev = endToken->previous();
while (prev && Token::simpleMatch(prev->previous(), "; ;"))
prev = prev->previous();
if (prev && Token::simpleMatch(prev->previous(), "} ;"))
prev = prev->previous();
if (Token::simpleMatch(prev, "}")) {
if (Token::simpleMatch(prev->link()->tokAt(-2), "} else {"))
return isReturnScope(prev) && isReturnScope(prev->link()->tokAt(-2));
if (Token::simpleMatch(prev->link()->previous(), ") {") &&
Token::simpleMatch(prev->link()->linkAt(-1)->previous(), "switch (") &&
!Token::findsimplematch(prev->link(), "break", prev)) {
return true;
}
if (Token::simpleMatch(prev->link()->previous(), ") {") &&
Token::simpleMatch(prev->link()->linkAt(-1)->previous(), "return (")) {
return true;
}
if (Token::Match(prev->link()->previous(), "[;{}] {"))
return isReturnScope(prev);
} else if (Token::simpleMatch(prev, ";")) {
// noreturn function
if (Token::simpleMatch(prev->previous(), ") ;") && Token::Match(prev->linkAt(-1)->tokAt(-2), "[;{}] %name% ("))
return true;
// return/goto statement
prev = prev->previous();
while (prev && !Token::Match(prev, ";|{|}|return|goto|throw|continue|break"))
prev = prev->previous();
return prev && prev->isName();
}
return false;
}
bool isVariableChanged(const Token *start, const Token *end, const unsigned int varid)
{
for (const Token *tok = start; tok != end; tok = tok->next()) {
if (tok->varId() == varid) {
if (Token::Match(tok, "%name% %assign%|++|--"))
return true;
if (Token::Match(tok->previous(), "++|-- %name%"))
return true;
if (Token::Match(tok->tokAt(-2), "[(,] & %var% [,)]"))
return true; // TODO: check if function parameter is const
if (Token::Match(tok->previous(), "[(,] %var% [,)]")) {
const Token *parent = tok->astParent();
while (parent && parent->str() == ",")
parent = parent->astParent();
if (parent && Token::Match(parent->previous(), "%name% (") && !parent->previous()->function())
return true;
// TODO: check if function parameter is non-const reference etc..
}
const Token *parent = tok->astParent();
while (Token::Match(parent, ".|::"))
parent = parent->astParent();
if (parent && parent->tokType() == Token::eIncDecOp)
return true;
}
}
return false;
}
int numberOfArguments(const Token *start)
{
int arguments=0;
const Token* const openBracket = start->next();
if (openBracket && openBracket->str()=="(" && openBracket->next() && openBracket->next()->str()!=")") {
const Token* argument=openBracket->next();
while (argument) {
++arguments;
argument = argument->nextArgument();
}
}
return arguments;
}