/* * Cppcheck - A tool for static C/C++ code analysis * Copyright (C) 2007-2013 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 . */ #include "tokenize.h" #include "checkassignif.h" #include "testsuite.h" #include extern std::ostringstream errout; class TestAssignIf : public TestFixture { public: TestAssignIf() : TestFixture("TestAssignIf") { } private: void run() { TEST_CASE(assignAndCompare); // assignment and comparison don't match TEST_CASE(mismatchingBitAnd); // overlapping bitmasks TEST_CASE(compare); // mismatching LHS/RHS in comparison TEST_CASE(multicompare); // mismatching comparisons } void check(const char code[]) { // Clear the error buffer.. errout.str(""); Settings settings; settings.addEnabled("style"); // Tokenize.. Tokenizer tokenizer(&settings, this); std::istringstream istr(code); tokenizer.tokenize(istr, "test.cpp"); const std::string str1(tokenizer.tokens()->stringifyList(0,true)); tokenizer.simplifyTokenList(); const std::string str2(tokenizer.tokens()->stringifyList(0,true)); // Ensure that the test case is not bad. if (str1 != str2) { warn(("Unsimplified code in test case. It looks like this test " "should either be cleaned up or moved to TestTokenizer or " "TestSimplifyTokens instead.\nstr1="+str1+"\nstr2="+str2).c_str()); } // Check char variable usage.. CheckAssignIf checkAssignIf(&tokenizer, &settings, this); checkAssignIf.assignIf(); checkAssignIf.comparison(); checkAssignIf.multiCondition(); } void assignAndCompare() { // & check("void foo(int x)\n" "{\n" " int y = x & 4;\n" " if (y == 3);\n" "}"); ASSERT_EQUALS("[test.cpp:3] -> [test.cpp:4]: (style) Mismatching assignment and comparison, comparison 'y==3' is always false.\n", errout.str()); check("void foo(int x)\n" "{\n" " int y = x & 4;\n" " if (y != 3);\n" "}"); ASSERT_EQUALS("[test.cpp:3] -> [test.cpp:4]: (style) Mismatching assignment and comparison, comparison 'y!=3' is always true.\n", errout.str()); // | check("void foo(int x) {\n" " int y = x | 0x14;\n" " if (y == 0x710);\n" "}"); ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (style) Mismatching assignment and comparison, comparison 'y==1808' is always false.\n", errout.str()); check("void foo(int x) {\n" " int y = x | 0x14;\n" " if (y == 0x71f);\n" "}"); ASSERT_EQUALS("", errout.str()); // various simple assignments check("void foo(int x) {\n" " int y = (x+1) | 1;\n" " if (y == 2);\n" "}"); ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (style) Mismatching assignment and comparison, comparison 'y==2' is always false.\n", errout.str()); check("void foo() {\n" " int y = 1 | x();\n" " if (y == 2);\n" "}"); ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (style) Mismatching assignment and comparison, comparison 'y==2' is always false.\n", errout.str()); // multiple conditions check("void foo(int x) {\n" " int y = x & 4;\n" " if ((y == 3) && (z == 1));\n" "}"); ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (style) Mismatching assignment and comparison, comparison 'y==3' is always false.\n", errout.str()); check("void foo(int x) {\n" " int y = x & 4;\n" " if ((x==123) || ((y == 3) && (z == 1)));\n" "}"); ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (style) Mismatching assignment and comparison, comparison 'y==3' is always false.\n", errout.str()); check("void f(int x) {\n" " int y = x & 7;\n" " if (setvalue(&y) && y != 8);\n" "}"); ASSERT_EQUALS("", errout.str()); // recursive checking into scopes check("void f(int x) {\n" " int y = x & 7;\n" " if (z) y=0;\n" " else { if (y==8); }\n" // always false "}"); ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:4]: (style) Mismatching assignment and comparison, comparison 'y==8' is always false.\n", errout.str()); // while check("void f(int x) {\n" " int y = x & 7;\n" " while (y==8);\n" // local variable => always false "}"); ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (style) Mismatching assignment and comparison, comparison 'y==8' is always false.\n", errout.str()); check("void f(int x) {\n" " extern int y; y = x & 7;\n" " while (y==8);\n" // non-local variable => no error "}"); ASSERT_EQUALS("", errout.str()); // calling function check("void f(int x) {\n" " int y = x & 7;\n" " do_something();\n" " if (y==8);\n" // local variable => always false "}"); ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:4]: (style) Mismatching assignment and comparison, comparison 'y==8' is always false.\n", errout.str()); check("void f(int x) {\n" " int y = x & 7;\n" " do_something(&y);\n" // passing variable => no error " if (y==8);\n" "}"); ASSERT_EQUALS("", errout.str()); check("void f(int x) {\n" " extern int y; y = x & 7;\n" " do_something();\n" " if (y==8);\n" // non-local variable => no error "}"); ASSERT_EQUALS("", errout.str()); // #4434 : false positive: ?: check("void f(int x) {\n" " x = x & 1;\n" " x = x & 1 ? 1 : -1;\n" " if(x != -1) { }\n" "}"); ASSERT_EQUALS("", errout.str()); // #4735 check("void f() {\n" " int x = *(char*)&0x12345678;\n" " if (x==18) { }\n" "}"); ASSERT_EQUALS("", errout.str()); // bailout: no variable info check("void foo(int x) {\n" " y = 2 | x;\n" // y not declared => no error " if(y == 1) {}\n" "}"); ASSERT_EQUALS("", errout.str()); // bailout: negative number check("void foo(int x) {\n" " int y = -2 | x;\n" // negative number => no error " if (y==1) {}\n" "}"); ASSERT_EQUALS("", errout.str()); // bailout: pass variable to function check("void foo(int x) {\n" " int y = 2 | x;\n" " bar(&y);\n" // pass variable to function => no error " if (y==1) {}\n" "}"); ASSERT_EQUALS("", errout.str()); } void mismatchingBitAnd() { check("void f(int a) {\n" " int b = a & 0xf0;\n" " b &= 1;\n" "}"); ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (style) Mismatching bitmasks. Result is always 0 (X = Y & 0xf0; Z = X & 0x1; => Z=0).\n", errout.str()); check("void f(int a) {\n" " int b = a & 0xf0;\n" " int c = b & 1;\n" "}"); ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (style) Mismatching bitmasks. Result is always 0 (X = Y & 0xf0; Z = X & 0x1; => Z=0).\n", errout.str()); check("void f(int a) {\n" " int b = a;" " switch (x) {\n" " case 1: b &= 1; break;\n" " case 2: b &= 2; break;\n" " };\n" "}"); ASSERT_EQUALS("", errout.str()); } void compare() { check("void foo(int x)\n" "{\n" " if (x & 4 == 3);\n" "}"); ASSERT_EQUALS("[test.cpp:3]: (style) Expression '(X & 0x4) == 0x3' is always false.\n", errout.str()); check("void foo(int x)\n" "{\n" " if ((x & 4) == 3);\n" "}"); ASSERT_EQUALS("[test.cpp:3]: (style) Expression '(X & 0x4) == 0x3' is always false.\n", errout.str()); check("void foo(int x)\n" "{\n" " if (x & 4 != 3);\n" "}"); ASSERT_EQUALS("[test.cpp:3]: (style) Expression '(X & 0x4) != 0x3' is always true.\n", errout.str()); check("void foo(int x)\n" "{\n" " if ((x | 4) == 3);\n" "}"); ASSERT_EQUALS("[test.cpp:3]: (style) Expression '(X | 0x4) == 0x3' is always false.\n", errout.str()); check("void foo(int x)\n" "{\n" " if ((x | 4) != 3);\n" "}"); ASSERT_EQUALS("[test.cpp:3]: (style) Expression '(X | 0x4) != 0x3' is always true.\n", errout.str()); // array check("void foo(int *x)\n" "{\n" " if (x[0] & 4 == 3);\n" "}"); ASSERT_EQUALS("[test.cpp:3]: (style) Expression '(X & 0x4) == 0x3' is always false.\n", errout.str()); // struct member check("void foo(struct X *x)\n" "{\n" " if (x->y & 4 == 3);\n" "}"); ASSERT_EQUALS("[test.cpp:3]: (style) Expression '(X & 0x4) == 0x3' is always false.\n", errout.str()); // expression check("void foo(int x)\n" "{\n" " if ((x+2) & 4 == 3);\n" "}"); ASSERT_EQUALS("[test.cpp:3]: (style) Expression '(X & 0x4) == 0x3' is always false.\n", errout.str()); } void multicompare() { check("void foo(int x)\n" "{\n" " if (x & 7);\n" " else { if (x == 1); }\n" "}"); ASSERT_EQUALS("[test.cpp:4]: (style) Expression is always false because 'else if' condition matches previous condition at line 3.\n", errout.str()); check("void foo(int x)\n" "{\n" " if (x & 7);\n" " else { if (x & 1); }\n" "}"); ASSERT_EQUALS("[test.cpp:4]: (style) Expression is always false because 'else if' condition matches previous condition at line 3.\n", errout.str()); } }; REGISTER_TEST(TestAssignIf)