cppcheck/testunusedvar.cpp

/*
 * cppcheck - c/c++ syntax checking
 * Copyright (C) 2007-2009 Daniel Marjamäki, Reijo Tomperi, Nicolas Le Cam
 *
 * 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/
 */



// Check for unused variables..

#define UNIT_TESTING
#include "testsuite.h"
#include "tokenize.h"
#include "checkother.h"

#include <sstream>
extern std::ostringstream errout;

class TestUnusedVar : public TestFixture
{
public:
    TestUnusedVar() : TestFixture("TestUnusedVar")
    { }

private:
    void check( const char code[] )
    {
        // Tokenize..
        Tokenizer tokenizer;
        std::istringstream istr(code);
        tokenizer.tokenize( istr, "test.cpp" );
        tokenizer.simplifyTokenList();

        // Clear the error buffer..
        errout.str("");

        // Check for unused variables..
        CheckOther checkOther( &tokenizer, this );
        checkOther.CheckStructMemberUsage();
    }

    void run()
    {
        TEST_CASE( structmember1 );
        TEST_CASE( structmember2 );
        TEST_CASE( structmember3 );

        TEST_CASE( localvar1 );
        TEST_CASE( localvar2 );
        TEST_CASE( localvar3 );
        TEST_CASE( localvar4 );
        TEST_CASE( localvar5 );

        // Don't give false positives for variables in structs/unions
        TEST_CASE( localvarStruct1 );
        TEST_CASE( localvarStruct2 );

        TEST_CASE( localvarOp );        // Usage with arithmetic operators
        TEST_CASE( localvarInvert );    // Usage with inverted variable
        TEST_CASE( localvarIf );        // Usage in if
        TEST_CASE( localvarIfElse );    // return tmp1 ? tmp2 : tmp3;
        TEST_CASE( localvarOpAssign );  // a |= b;
    }

    void structmember1()
    {
        check( "struct abc\n"
               "{\n"
               "    int a;\n"
               "    int b;\n"
               "    int c;\n"
               "};\n" );
        ASSERT_EQUALS( std::string("[test.cpp:3]: struct or union member 'abc::a' is never used\n"
                                   "[test.cpp:4]: struct or union member 'abc::b' is never used\n"
                                   "[test.cpp:5]: struct or union member 'abc::c' is never used\n"), errout.str() );
    }

    void structmember2()
    {
        check( "struct ABC\n"
               "{\n"
               "    int a;\n"
               "    int b;\n"
               "    int c;\n"
               "};\n"
               "\n"
               "void foo()\n"
               "{\n"
               "    struct ABC abc;\n"
               "    int a = abc.a;\n"
               "    int b = abc.b;\n"
               "    int c = abc.c;\n"
               "}\n" );
        ASSERT_EQUALS( std::string(""), errout.str() );
    }

    void structmember3()
    {
        check( "struct ABC\n"
               "{\n"
               "    int a;\n"
               "    int b;\n"
               "    int c;\n"
               "};\n"
               "\n"
               "static struct ABC abc[] = { {1, 2, 3} };\n"
               "\n"
               "void foo()\n"
               "{\n"
               "    int a = abc[0].a;\n"
               "    int b = abc[0].b;\n"
               "    int c = abc[0].c;\n"
               "}\n" );
        ASSERT_EQUALS( std::string(""), errout.str() );
    }





    void functionVariableUsage( const char code[] )
    {
        // Tokenize..
        Tokenizer tokenizer;
        std::istringstream istr(code);
        tokenizer.tokenize( istr, "test.cpp" );
        tokenizer.simplifyTokenList();

        // Clear the error buffer..
        errout.str("");

        // Check for unused variables..
        CheckOther checkOther( &tokenizer, this );
        checkOther.functionVariableUsage();
    }

    void localvar1()
    {
        functionVariableUsage( "void foo()\n"
                               "{\n"
                               "    int i = 0;\n"
                               "}\n" );
        ASSERT_EQUALS( std::string("[test.cpp:2]: Variable 'i' is assigned a value that is never used\n"), errout.str() );
    }

    void localvar2()
    {
        functionVariableUsage( "void foo()\n"
                               "{\n"
                               "    int i;\n"
                               "    return i;\n"
                               "}\n" );
        ASSERT_EQUALS( std::string("[test.cpp:2]: Variable 'i' is not assigned a value\n"), errout.str() );
    }

    void localvar3()
    {
        functionVariableUsage( "void foo()\n"
                               "{\n"
                               "    int i;\n"
                               "    if ( abc )\n"
                               "        ;\n"
                               "    else i = 0;\n"
                               "}\n" );
        ASSERT_EQUALS( std::string("[test.cpp:2]: Variable 'i' is assigned a value that is never used\n"), errout.str() );
    }

    void localvar4()
    {
        functionVariableUsage( "void foo()\n"
                               "{\n"
                               "    int i = 0;\n"
                               "    f(i);\n"
                               "}\n" );
        ASSERT_EQUALS( std::string(""), errout.str() );
    }

    void localvar5()
    {
        functionVariableUsage( "void foo()\n"
                               "{\n"
                               "    int a = 0;\n"
                               "    b = (char)a;\n"
                               "}\n" );
        ASSERT_EQUALS( std::string(""), errout.str() );
    }



    void localvarStruct1()
    {
        functionVariableUsage( "void foo()\n"
                               "{\n"
                               "    static const struct{ int x, y, w, h; } bounds = {1,2,3,4};\n"
                               "    return bounds.x + bounds.y + bounds.w + bounds.h;\n"
                               "}\n" );
        ASSERT_EQUALS( std::string(""), errout.str() );
    }

    void localvarStruct2()
    {
        functionVariableUsage( "void foo()\n"
                               "{\n"
                               "    struct ABC { int a, b, c; };\n"
                               "    struct ABC abc = { 1, 2, 3 };\n"
                               "}\n" );
        ASSERT_EQUALS( std::string(""), errout.str() );
    }



    void localvarOp()
    {
        const char op[] = "+-*/%&|^";
        for (const char *p = op; *p; ++p)
        {
            std::string code( "int main()\n"
                              "{\n"
                              "    int tmp = 10;\n"
                              "    return 123 " + std::string(1, *p) + " tmp;\n"
                              "}\n" );
            functionVariableUsage( code.c_str() );
            ASSERT_EQUALS( std::string(""), errout.str() );
        }
    }

    void localvarInvert()
    {
        functionVariableUsage( "int main()\n"
                               "{\n"
                               "    int tmp = 10;\n"
                               "    return ~tmp;\n"
                               "}\n" );
        ASSERT_EQUALS( std::string(""), errout.str() );
    }

    void localvarIf()
    {
        functionVariableUsage( "int main()\n"
                               "{\n"
                               "    int tmp = 10;\n"
                               "    if ( tmp )\n"
                               "        return 1;\n"
                               "    return 0;\n"
                               "}\n" );
        ASSERT_EQUALS( std::string(""), errout.str() );
    }

    void localvarIfElse()
    {
        functionVariableUsage( "int foo()\n"
                               "{\n"
                               "    int tmp1 = 1;\n"
                               "    int tmp2 = 2;\n"
                               "    int tmp3 = 3;\n"
                               "    return tmp1 ? tmp2 : tmp3;\n"
                               "}\n" );
        ASSERT_EQUALS( std::string(""), errout.str() );
    }

    void localvarOpAssign()
    {
        functionVariableUsage( "void foo()\n"
                               "{\n"
                               "    int a = 1;\n"
                               "    int b = 2;\n"
                               "    a |= b;\n"
                               "}\n" );
        ASSERT_EQUALS( std::string("[test.cpp:2]: Variable 'a' is assigned a value that is never used\n"), errout.str() );
    }


};

REGISTER_TEST( TestUnusedVar )