cppcheck/lib/executionpath.cpp

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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2009 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 "executionpath.h"
#include "token.h"
#include <memory>
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// default : bail out if the condition is has variable handling
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bool ExecutionPath::parseCondition(const Token &tok, std::list<ExecutionPath *> & checks)
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{
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if (Token::Match(tok.tokAt(-3), "!!else if ("))
{
++ifinfo;
}
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unsigned int parlevel = 0;
for (const Token *tok2 = &tok; tok2; tok2 = tok2->next())
{
if (tok2->str() == "(")
++parlevel;
else if (tok2->str() == ")")
{
if (parlevel == 0)
break;
--parlevel;
}
else if (Token::Match(tok2, ";{}"))
break;
if (tok2->varId() != 0)
{
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if (ifinfo > 1)
return true;
else
bailOutVar(checks, tok2->varId());
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}
}
return false;
}
static const Token *checkExecutionPaths_(const Token *tok, std::list<ExecutionPath *> &checks)
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{
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if (!tok || tok->str() == "}" || checks.empty())
return 0;
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const std::auto_ptr<ExecutionPath> check(checks.front()->copy());
for (; tok; tok = tok->next())
{
if (tok->str() == "}")
return 0;
if (Token::simpleMatch(tok, "while ("))
{
// parse condition
if (checks.size() > 10 || check->parseCondition(*tok->tokAt(2), checks))
{
ExecutionPath::bailOut(checks);
return 0;
}
// skip "while (fgets()!=NULL)"
if (Token::simpleMatch(tok, "while ( fgets ("))
{
const Token *tok2 = tok->tokAt(3)->link();
if (Token::simpleMatch(tok2, ") ) {"))
{
tok = tok2->tokAt(2)->link();
if (!tok)
break;
continue;
}
}
}
// for/while/switch/do .. bail out
if (Token::Match(tok, "for|while|switch|do"))
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{
// goto {
const Token *tok2 = tok->next();
if (tok2 && tok2->str() == "(")
tok2 = tok2->link();
if (tok2 && tok2->str() == ")")
tok2 = tok2->next();
if (!tok2 || tok2->str() != "{")
{
ExecutionPath::bailOut(checks);
return 0;
}
// skip { .. }
tok2 = tok2->link();
// if "do { .. } while ( .." , goto end of while..
if (Token::simpleMatch(tok, "do {") && Token::simpleMatch(tok2, "} while ("))
tok2 = tok2->tokAt(2)->link();
// bail out all variables used in this for/while/switch/do
for (; tok && tok != tok2; tok = tok->next())
{
if (tok->varId())
ExecutionPath::bailOutVar(checks, tok->varId());
}
continue;
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}
// .. ) { ... } => bail out
if (Token::simpleMatch(tok, ") {"))
{
ExecutionPath::bailOut(checks);
return 0;
}
if (Token::Match(tok, "abort|exit ("))
{
ExecutionPath::bailOut(checks);
return 0;
}
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// don't parse into "struct type { .."
if (Token::Match(tok, "struct|class %type% {|:"))
{
while (tok && tok->str() != "{" && tok->str() != ";")
tok = tok->next();
tok = tok ? tok->link() : 0;
}
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if (Token::Match(tok, "= {"))
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{
tok = tok->next()->link();
if (!tok)
{
ExecutionPath::bailOut(checks);
return 0;
}
continue;
}
// ; { ... }
if (Token::Match(tok->previous(), "[;{}] {"))
{
const Token *tokerr = checkExecutionPaths_(tok->next(), checks);
if (tokerr)
{
ExecutionPath::bailOut(checks);
return tokerr;
}
tok = tok->link();
continue;
}
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if (tok->str() == "if")
{
std::list<ExecutionPath *> newchecks;
while (tok->str() == "if")
{
// goto "("
tok = tok->next();
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// parse condition
if (checks.size() > 10 || check->parseCondition(*tok->next(), checks))
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{
ExecutionPath::bailOut(checks);
ExecutionPath::bailOut(newchecks);
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return 0;
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}
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// goto ")"
tok = tok ? tok->link() : 0;
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// goto "{"
tok = tok ? tok->next() : 0;
if (!Token::simpleMatch(tok, "{"))
{
ExecutionPath::bailOut(checks);
ExecutionPath::bailOut(newchecks);
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return 0;
}
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// Recursively check into the if ..
{
std::list<ExecutionPath *> c;
std::list<ExecutionPath *>::iterator it;
for (it = checks.begin(); it != checks.end(); ++it)
c.push_back((*it)->copy());
const Token *tokerr = checkExecutionPaths_(tok->next(), c);
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if (tokerr)
{
ExecutionPath::bailOut(c);
ExecutionPath::bailOut(newchecks);
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return tokerr;
}
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while (!c.empty())
{
newchecks.push_back(c.back());
c.pop_back();
}
}
// goto "}"
tok = tok->link();
// there is no else => break out
if (Token::Match(tok, "} !!else"))
break;
// parse next "if"..
tok = tok->tokAt(2);
if (tok->str() == "if")
continue;
// there is no "if"..
const Token *tokerr = checkExecutionPaths_(tok->next(), checks);
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if (tokerr)
{
ExecutionPath::bailOut(newchecks);
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return tokerr;
}
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tok = tok->link();
if (!tok)
{
ExecutionPath::bailOut(newchecks);
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return 0;
}
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}
std::list<ExecutionPath *>::iterator it;
for (it = newchecks.begin(); it != newchecks.end(); ++it)
checks.push_back(*it);
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}
{
bool foundError = false;
tok = check->parse(*tok, foundError, checks);
if (checks.empty())
return 0;
else if (foundError)
return tok;
}
// return/throw ends all execution paths
if (tok->str() == "return" || tok->str() == "throw")
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{
ExecutionPath::bailOut(checks);
}
}
return 0;
}
void checkExecutionPaths(const Token *tok, ExecutionPath *c)
{
for (; tok; tok = tok->next())
{
if (tok->str() != ")")
continue;
// Start of implementation..
if (Token::Match(tok, ") const| {"))
{
// goto the "{"
tok = tok->next();
if (tok->str() == "const")
tok = tok->next();
std::list<ExecutionPath *> checks;
checks.push_back(c->copy());
checkExecutionPaths_(tok, checks);
c->end(checks, tok->link());
while (!checks.empty())
{
delete checks.back();
checks.pop_back();
}
// skip this scope - it has been checked
tok = tok->link();
}
}
}