cppcheck/lib/astutils.cpp

360 lines
13 KiB
C++

/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2015 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 "astutils.h"
#include "symboldatabase.h"
#include "token.h"
#include "tokenize.h"
#include <set>
static bool isChar(const Variable* var)
{
return (var && !var->isPointer() && !var->isArray() && var->typeStartToken()->str() == "char");
}
static bool isSignedChar(const Variable* var)
{
return (isChar(var) && !var->typeStartToken()->isUnsigned());
}
bool astIsSignedChar(const Token *tok)
{
if (!tok)
return false;
if (tok->str() == "*" && tok->astOperand1() && !tok->astOperand2()) {
const Variable *var = tok->astOperand1()->variable();
if (!var || !var->isPointer())
return false;
const Token *type = var->typeStartToken();
while (type && type->str() == "const")
type = type->next();
return (type && type->str() == "char" && !type->isUnsigned());
}
return isSignedChar(tok->variable());
}
bool astIsIntegral(const Token *tok, bool unknown)
{
// TODO: handle arrays
if (tok->isNumber())
return MathLib::isInt(tok->str());
if (tok->isName()) {
if (tok->variable())
return tok->variable()->isIntegralType();
return unknown;
}
if (tok->str() == "(") {
// cast
if (Token::Match(tok, "( const| float|double )"))
return false;
// Function call
if (tok->previous()->function()) {
if (Token::Match(tok->previous()->function()->retDef, "float|double"))
return false;
else if (Token::Match(tok->previous()->function()->retDef, "bool|char|short|int|long"))
return true;
}
if (tok->strAt(-1) == "sizeof")
return true;
return unknown;
}
if (tok->astOperand2() && (tok->str() == "." || tok->str() == "::"))
return astIsIntegral(tok->astOperand2(), unknown);
if (tok->astOperand1() && tok->str() != "?")
return astIsIntegral(tok->astOperand1(), unknown);
return unknown;
}
bool astIsFloat(const Token *tok, bool unknown)
{
// TODO: handle arrays
if (tok->isNumber())
return MathLib::isFloat(tok->str());
if (tok->isName()) {
if (tok->variable())
return tok->variable()->isFloatingType();
return unknown;
}
if (tok->str() == "(") {
// cast
if (Token::Match(tok, "( const| float|double )"))
return true;
// Function call
if (tok->previous()->function())
return Token::Match(tok->previous()->function()->retDef, "float|double");
if (tok->strAt(-1) == "sizeof")
return false;
return unknown;
}
if (tok->astOperand2() && (tok->str() == "." || tok->str() == "::"))
return astIsFloat(tok->astOperand2(), unknown);
if (tok->astOperand1() && tok->str() != "?" && astIsFloat(tok->astOperand1(), unknown))
return true;
if (tok->astOperand2() && astIsFloat(tok->astOperand2(), unknown))
return true;
if (tok->isOp())
return false;
return unknown;
}
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 "";
}
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()) {
if (tok->astOperand1() && tok->astOperand1()->str() == rhs) {
// Invert comparator
std::string s = tok->str();
if (s[0] == '>')
s[0] = '<';
else if (s[0] == '<')
s[0] = '>';
if (s == comp) {
ret = tok->astOperand2();
}
} else if (tok->str() == comp && tok->astOperand2() && tok->astOperand2()->str() == rhs) {
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, const Token *tok1, const Token *tok2, const std::set<std::string> &constFunctions)
{
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()) {
if ((Token::Match(tok1,"<|>") && Token::Match(tok2,"<|>")) ||
(Token::Match(tok1,"<=|>=") && Token::Match(tok2,"<=|>="))) {
return isSameExpression(cpp, tok1->astOperand1(), tok2->astOperand2(), constFunctions) &&
isSameExpression(cpp, tok1->astOperand2(), tok2->astOperand1(), constFunctions);
}
return false;
}
if (tok1->str() == "." && tok1->originalName() != tok2->originalName())
return false;
if (tok1->isExpandedMacro() || tok2->isExpandedMacro())
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())
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->isName() || t1->str() == "*")) {
t1 = t1->next();
t2 = t2->next();
}
if (!t1 || !t2 || t1->str() != ")" || t2->str() != ")")
return false;
}
bool noncommuative_equals =
isSameExpression(cpp, tok1->astOperand1(), tok2->astOperand1(), constFunctions);
noncommuative_equals = noncommuative_equals &&
isSameExpression(cpp, tok1->astOperand2(), tok2->astOperand2(), constFunctions);
if (noncommuative_equals)
return true;
const bool commutative = tok1->astOperand1() && tok1->astOperand2() && Token::Match(tok1, "%or%|%oror%|+|*|&|&&|^|==|!=");
bool commuative_equals = commutative &&
isSameExpression(cpp, tok1->astOperand2(), tok2->astOperand1(), constFunctions);
commuative_equals = commuative_equals &&
isSameExpression(cpp, tok1->astOperand1(), tok2->astOperand2(), constFunctions);
// in c++, "a"+b might be different to b+"a"
if (cpp && commuative_equals && 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 commuative_equals;
}
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, cond1->astOperand1(), cond2->astOperand2(), constFunctions);
if (cond2->astOperand2() && cond2->astOperand2()->str() == "0")
return isSameExpression(cpp, cond1->astOperand1(), cond2->astOperand1(), constFunctions);
}
return isSameExpression(cpp, cond1->astOperand1(), cond2, constFunctions);
}
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, cond1->astOperand1(), cond2->astOperand1(), constFunctions) &&
isSameExpression(cpp, cond1->astOperand2(), cond2->astOperand2(), constFunctions)) {
comp2 = cond2->str();
} else if (isSameExpression(cpp, cond1->astOperand1(), cond2->astOperand2(), constFunctions) &&
isSameExpression(cpp, cond1->astOperand2(), cond2->astOperand1(), constFunctions)) {
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)
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;
}