253 lines
9.3 KiB
C++
253 lines
9.3 KiB
C++
/*
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* Cppcheck - A tool for static C/C++ code analysis
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* Copyright (C) 2007-2013 Daniel Marjamäki and Cppcheck team.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "tokenize.h"
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#include "checkassignif.h"
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#include "testsuite.h"
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#include <sstream>
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extern std::ostringstream errout;
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class TestAssignIf : public TestFixture {
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public:
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TestAssignIf() : TestFixture("TestAssignIf")
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{ }
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private:
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void run() {
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TEST_CASE(assignAndCompare); // assignment and comparison don't match
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TEST_CASE(mismatchingBitAnd); // overlapping bitmasks
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TEST_CASE(compare); // mismatching LHS/RHS in comparison
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TEST_CASE(multicompare); // mismatching comparisons
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}
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void check(const char code[]) {
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// Clear the error buffer..
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errout.str("");
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Settings settings;
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settings.addEnabled("style");
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// Tokenize..
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Tokenizer tokenizer(&settings, this);
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std::istringstream istr(code);
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tokenizer.tokenize(istr, "test.cpp");
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tokenizer.simplifyTokenList();
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// Check char variable usage..
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CheckAssignIf checkAssignIf(&tokenizer, &settings, this);
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checkAssignIf.assignIf();
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checkAssignIf.comparison();
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checkAssignIf.multiCondition();
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}
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void assignAndCompare() {
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// &
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check("void foo(int x)\n"
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"{\n"
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" int y = x & 4;\n"
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" if (y == 3);\n"
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"}\n");
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ASSERT_EQUALS("[test.cpp:3] -> [test.cpp:4]: (style) Mismatching assignment and comparison, comparison 'y==3' is always false.\n", errout.str());
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check("void foo(int x)\n"
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"{\n"
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" int y = x & 4;\n"
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" if (y != 3);\n"
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"}\n");
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ASSERT_EQUALS("[test.cpp:3] -> [test.cpp:4]: (style) Mismatching assignment and comparison, comparison 'y!=3' is always true.\n", errout.str());
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// |
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check("void foo(int x) {\n"
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" int y = x | 0x14;\n"
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" if (y == 0x710);\n"
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"}");
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ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (style) Mismatching assignment and comparison, comparison 'y==1808' is always false.\n", errout.str());
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check("void foo(int x) {\n"
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" int y = x | 0x14;\n"
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" if (y == 0x71f);\n"
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"}");
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ASSERT_EQUALS("", errout.str());
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// various simple assignments
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check("void foo(int x) {\n"
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" int y = (x+1) | 1;\n"
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" if (y == 2);\n"
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"}");
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ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (style) Mismatching assignment and comparison, comparison 'y==2' is always false.\n", errout.str());
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check("void foo() {\n"
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" int y = 1 | x();\n"
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" if (y == 2);\n"
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"}");
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ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (style) Mismatching assignment and comparison, comparison 'y==2' is always false.\n", errout.str());
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// multiple conditions
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check("void foo(int x) {\n"
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" int y = x & 4;\n"
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" if ((y == 3) && (z == 1));\n"
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"}\n");
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ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (style) Mismatching assignment and comparison, comparison 'y==3' is always false.\n", errout.str());
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check("void foo(int x) {\n"
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" int y = x & 4;\n"
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" if ((x==123) || ((y == 3) && (z == 1)));\n"
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"}\n");
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ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (style) Mismatching assignment and comparison, comparison 'y==3' is always false.\n", errout.str());
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check("void f(int x) {\n"
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" int y = x & 7;\n"
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" if (setvalue(&y) && y != 8);\n"
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"}");
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ASSERT_EQUALS("", errout.str());
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// recursive checking into scopes
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check("void f(int x) {\n"
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" int y = x & 7;\n"
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" if (z) y=0;\n"
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" else if (y==8);\n" // always false
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"}");
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ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:4]: (style) Mismatching assignment and comparison, comparison 'y==8' is always false.\n", errout.str());
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// while
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check("void f(int x) {\n"
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" int y = x & 7;\n"
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" while (y==8);\n" // local variable => always false
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"}");
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ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (style) Mismatching assignment and comparison, comparison 'y==8' is always false.\n", errout.str());
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check("void f(int x) {\n"
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" extern int y; y = x & 7;\n"
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" while (y==8);\n" // non-local variable => no error
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"}");
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ASSERT_EQUALS("", errout.str());
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// calling function
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check("void f(int x) {\n"
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" int y = x & 7;\n"
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" do_something();\n"
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" if (y==8);\n" // local variable => always false
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"}");
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ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:4]: (style) Mismatching assignment and comparison, comparison 'y==8' is always false.\n", errout.str());
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check("void f(int x) {\n"
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" extern int y; y = x & 7;\n"
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" do_something();\n"
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" if (y==8);\n" // non-local variable => no error
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"}");
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ASSERT_EQUALS("", errout.str());
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// #4434 : false positive: ?:
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check("void f(int x) {\n"
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" x = x & 1;\n"
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" x = x & 1 ? 1 : -1;\n"
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" if(x != -1) { }\n"
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"}");
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ASSERT_EQUALS("", errout.str());
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}
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void mismatchingBitAnd() {
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check("void f(int a) {\n"
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" int b = a & 0xf0;\n"
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" b &= 1;\n"
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"}");
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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());
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check("void f(int a) {\n"
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" int b = a & 0xf0;\n"
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" int c = b & 1;\n"
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"}");
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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());
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}
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void compare() {
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check("void foo(int x)\n"
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"{\n"
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" if (x & 4 == 3);\n"
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"}\n");
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ASSERT_EQUALS("[test.cpp:3]: (style) Expression '(X & 0x4) == 0x3' is always false.\n", errout.str());
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check("void foo(int x)\n"
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"{\n"
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" if ((x & 4) == 3);\n"
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"}\n");
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ASSERT_EQUALS("[test.cpp:3]: (style) Expression '(X & 0x4) == 0x3' is always false.\n", errout.str());
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check("void foo(int x)\n"
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"{\n"
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" if (x & 4 != 3);\n"
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"}\n");
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ASSERT_EQUALS("[test.cpp:3]: (style) Expression '(X & 0x4) != 0x3' is always true.\n", errout.str());
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check("void foo(int x)\n"
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"{\n"
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" if ((x | 4) == 3);\n"
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"}\n");
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ASSERT_EQUALS("[test.cpp:3]: (style) Expression '(X | 0x4) == 0x3' is always false.\n", errout.str());
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check("void foo(int x)\n"
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"{\n"
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" if ((x | 4) != 3);\n"
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"}\n");
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ASSERT_EQUALS("[test.cpp:3]: (style) Expression '(X | 0x4) != 0x3' is always true.\n", errout.str());
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// array
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check("void foo(int *x)\n"
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"{\n"
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" if (x[0] & 4 == 3);\n"
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"}\n");
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ASSERT_EQUALS("[test.cpp:3]: (style) Expression '(X & 0x4) == 0x3' is always false.\n", errout.str());
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// struct member
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check("void foo(struct X *x)\n"
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"{\n"
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" if (x->y & 4 == 3);\n"
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"}\n");
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ASSERT_EQUALS("[test.cpp:3]: (style) Expression '(X & 0x4) == 0x3' is always false.\n", errout.str());
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// expression
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check("void foo(int x)\n"
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"{\n"
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" if ((x+2) & 4 == 3);\n"
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"}\n");
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ASSERT_EQUALS("[test.cpp:3]: (style) Expression '(X & 0x4) == 0x3' is always false.\n", errout.str());
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}
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void multicompare() {
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check("void foo(int x)\n"
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"{\n"
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" if (x & 7);\n"
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" else if (x == 1);\n"
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"}\n");
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ASSERT_EQUALS("[test.cpp:4]: (style) Expression is always false because 'else if' condition matches previous condition at line 3.\n", errout.str());
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check("void foo(int x)\n"
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"{\n"
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" if (x & 7);\n"
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" else if (x & 1);\n"
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"}\n");
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ASSERT_EQUALS("[test.cpp:4]: (style) Expression is always false because 'else if' condition matches previous condition at line 3.\n", errout.str());
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}
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};
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REGISTER_TEST(TestAssignIf)
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