check64bit.cpp

/*
 * Cppcheck - A tool for static C/C++ code analysis
 * Copyright (C) 2007-2012 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/>.
 */

//---------------------------------------------------------------------------
// 64-bit portability
//---------------------------------------------------------------------------

#include "check64bit.h"
#include "symboldatabase.h"

//---------------------------------------------------------------------------

// Register this check class (by creating a static instance of it)
namespace {
    Check64BitPortability instance;
}

/** Is given variable a pointer or array? */
static bool isaddr(const Variable *var)
{
    return (var && (var->isPointer() || var->isArray()));
}

/** Is given variable an integer variable */
static bool isint(const Variable *var)
{
    return (var && Token::Match(var->nameToken()->previous(), "int|long|DWORD %var% !!["));
}

void Check64BitPortability::pointerassignment()
{
    if (!_settings->isEnabled("portability"))
        return;

    const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();

    // Check return values
    for (std::list<Scope>::const_iterator scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {
        if (scope->type != Scope::eFunction || scope->function == 0 || !scope->function->hasBody) // We only look for functions with a body
            continue;

        bool retPointer = false;
        if (scope->function->token->strAt(-1) == "*") // Function returns a pointer
            retPointer = true;
        else if (Token::Match(scope->function->token->previous(), "int|long|DWORD")) // Function returns an integer
            ;
        else
            continue;

        for (const Token* tok = scope->classStart; tok != scope->classEnd; tok = tok->next()) {
            if (Token::Match(tok, "return %var% [;+]")) {
                const Variable *var = symbolDatabase->getVariableFromVarId(tok->next()->varId());
                if (retPointer && isint(var))
                    returnIntegerError(tok);
                else if (!retPointer && isaddr(var))
                    returnPointerError(tok);
            }
        }
    }

    // Check assignements
    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
        if (Token::Match(tok, "[;{}] %var% = %var% [;+]")) {

            const Variable *var1(symbolDatabase->getVariableFromVarId(tok->next()->varId()));
            const Variable *var2(symbolDatabase->getVariableFromVarId(tok->tokAt(3)->varId()));

            if (isaddr(var1) && isint(var2) && tok->strAt(4) != "+")
                assignmentIntegerToAddressError(tok->next());

            else if (isint(var1) && isaddr(var2) && !tok->tokAt(3)->isPointerCompare()) {
                // assigning address => warning
                // some trivial addition => warning
                if (Token::Match(tok->tokAt(4), "+ %any% !!;"))
                    continue;

                assignmentAddressToIntegerError(tok->next());
            }
        }
    }
}

void Check64BitPortability::assignmentAddressToIntegerError(const Token *tok)
{
    reportError(tok, Severity::portability,
                "AssignmentAddressToInteger",
                "Assigning a pointer to an integer is not portable.\n"
                "Assigning a pointer to an integer (int/long/etc) is not portable across different platforms and "
                "compilers. For example in 32-bit Windows and linux they are same width, but in 64-bit Windows and linux "
                "they are of different width. In worst case you end up assigning 64-bit address to 32-bit integer. The safe "
                "way is to store addresses only in pointer types (or typedefs like uintptr_t).");
}

void Check64BitPortability::assignmentIntegerToAddressError(const Token *tok)
{
    reportError(tok, Severity::portability,
                "AssignmentIntegerToAddress",
                "Assigning an integer to a pointer is not portable.\n"
                "Assigning an integer (int/long/etc) to a pointer is not portable across different platforms and "
                "compilers. For example in 32-bit Windows and linux they are same width, but in 64-bit Windows and linux "
                "they are of different width. In worst case you end up assigning 64-bit integer to 32-bit pointer. The safe "
                "way is to store addresses only in pointer types (or typedefs like uintptr_t).");
}

void Check64BitPortability::returnPointerError(const Token *tok)
{
    reportError(tok, Severity::portability,
                "CastAddressToIntegerAtReturn",
                "Returning an address value in a function with integer return type is not portable.\n"
                "Returning an address value in a function with integer (int/long/etc) return type is not portable across "
                "different platforms and compilers. For example in 32-bit Windows and Linux they are same width, but in "
                "64-bit Windows and Linux they are of different width. In worst case you end up casting 64-bit address down "
                "to 32-bit integer. The safe way is to always return an integer.");
}

void Check64BitPortability::returnIntegerError(const Token *tok)
{
    reportError(tok, Severity::portability,
                "CastIntegerToAddressAtReturn",
                "Returning an integer in a function with pointer return type is not portable.\n"
                "Returning an integer (int/long/etc) in a function with pointer return type is not portable across different "
                "platforms and compilers. For example in 32-bit Windows and Linux they are same width, but in 64-bit Windows "
                "and Linux they are of different width. In worst case you end up casting 64-bit integer down to 32-bit pointer. "
                "The safe way is to always return a pointer.");
}