AssignIf: Added new check. Ticket: #2909

Makefile

@@ -47,6 +47,7 @@ MAN_SOURCE=man/cppcheck.1.xml
 ###### Object Files
 
 LIBOBJ =      lib/check64bit.o \
+              lib/checkassignif.o \
               lib/checkautovariables.o \
               lib/checkbufferoverrun.o \
               lib/checkclass.o \
@@ -81,6 +82,7 @@ CLIOBJ =      cli/cmdlineparser.o \
 
 TESTOBJ =     test/options.o \
               test/test64bit.o \
+              test/testassignif.o \
               test/testautovariables.o \
               test/testbufferoverrun.o \
               test/testcharvar.o \
@@ -170,6 +172,9 @@ install: cppcheck
 lib/check64bit.o: lib/check64bit.cpp lib/check64bit.h lib/check.h lib/token.h lib/tokenize.h lib/settings.h lib/errorlogger.h lib/symboldatabase.h lib/mathlib.h
 	$(CXX) $(CPPFLAGS) $(CXXFLAGS) ${INCLUDE_FOR_LIB} -c -o lib/check64bit.o lib/check64bit.cpp
 
+lib/checkassignif.o: lib/checkassignif.cpp lib/checkassignif.h lib/check.h lib/token.h lib/tokenize.h lib/settings.h lib/errorlogger.h lib/symboldatabase.h lib/mathlib.h
+	$(CXX) $(CPPFLAGS) $(CXXFLAGS) ${INCLUDE_FOR_LIB} -c -o lib/checkassignif.o lib/checkassignif.cpp
+
 lib/checkautovariables.o: lib/checkautovariables.cpp lib/checkautovariables.h lib/check.h lib/token.h lib/tokenize.h lib/settings.h lib/errorlogger.h lib/symboldatabase.h lib/mathlib.h
 	$(CXX) $(CPPFLAGS) $(CXXFLAGS) ${INCLUDE_FOR_LIB} -c -o lib/checkautovariables.o lib/checkautovariables.cpp
 
@@ -266,6 +271,9 @@ test/options.o: test/options.cpp test/options.h
 test/test64bit.o: test/test64bit.cpp lib/tokenize.h lib/check64bit.h lib/check.h lib/token.h lib/settings.h lib/errorlogger.h test/testsuite.h test/redirect.h
 	$(CXX) $(CPPFLAGS) $(CXXFLAGS) ${INCLUDE_FOR_TEST} -c -o test/test64bit.o test/test64bit.cpp
 
+test/testassignif.o: test/testassignif.cpp lib/tokenize.h lib/checkassignif.h lib/check.h lib/token.h lib/settings.h lib/errorlogger.h test/testsuite.h test/redirect.h
+	$(CXX) $(CPPFLAGS) $(CXXFLAGS) ${INCLUDE_FOR_TEST} -c -o test/testassignif.o test/testassignif.cpp
+
 test/testautovariables.o: test/testautovariables.cpp lib/tokenize.h lib/checkautovariables.h lib/check.h lib/token.h lib/settings.h lib/errorlogger.h test/testsuite.h test/redirect.h
 	$(CXX) $(CPPFLAGS) $(CXXFLAGS) ${INCLUDE_FOR_TEST} -c -o test/testautovariables.o test/testautovariables.cpp
 

lib/checkassignif.cpp

@@ -0,0 +1,77 @@
+/*
+ * Cppcheck - A tool for static C/C++ code analysis
+ * Copyright (C) 2007-2011 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/>.
+ */
+
+//---------------------------------------------------------------------------
+// Check for assignment / condition mismatches
+//---------------------------------------------------------------------------
+
+#include "checkassignif.h"
+#include "symboldatabase.h"
+
+//---------------------------------------------------------------------------
+
+// Register this check class (by creating a static instance of it)
+namespace
+{
+CheckAssignIf instance;
+}
+
+
+void CheckAssignIf::check()
+{
+    if (!_settings->_checkCodingStyle)
+        return;
+
+    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
+    {
+        if (tok->str() != "=")
+            continue;
+
+        if (Token::Match(tok->tokAt(-2), "[;{}] %var% = %var% & %num% ;"))
+        {
+            const unsigned int varid(tok->previous()->varId());
+            if (varid == 0)
+                continue;
+
+            const MathLib::bigint num = MathLib::toLongNumber(tok->strAt(3));
+            if (num < 0)
+                continue;
+
+            for (const Token *tok2 = tok->tokAt(4); tok2; tok2 = tok2->next())
+            {
+                if (tok2->str() == "(" || tok2->str() == "}" || tok2->str() == "=")
+                    break;
+                if (Token::Match(tok2,"if ( %varid% %any% %num% ) ", varid))
+                {
+                    const std::string op(tok2->strAt(3));
+                    const MathLib::bigint num2 = MathLib::toLongNumber(tok2->strAt(4));
+                    if (op == "==" && (num & num2) != num2)
+                        mismatchError(tok2);
+                    break;
+                }
+            }
+        }
+    }
+}
+
+void CheckAssignIf::mismatchError(const Token *tok)
+{
+    reportError(tok, Severity::style,
+                "assignIfMismatchError",
+                "Mismatching assignment and condition, condition is always false");
+}

lib/checkassignif.h

@@ -0,0 +1,83 @@
+/*
+ * Cppcheck - A tool for static C/C++ code analysis
+ * Copyright (C) 2007-2011 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/>.
+ */
+
+
+//---------------------------------------------------------------------------
+#ifndef checkassignifH
+#define checkassignifH
+//---------------------------------------------------------------------------
+
+#include "check.h"
+
+
+/// @addtogroup Checks
+/// @{
+
+/**
+ * @brief Check for assignment / condition mismatches
+ */
+
+class CheckAssignIf : public Check
+{
+public:
+    /** This constructor is used when registering the CheckAssignIf */
+    CheckAssignIf() : Check(myName())
+    {
+    }
+
+    /** This constructor is used when running checks. */
+    CheckAssignIf(const Tokenizer *tokenizer, const Settings *settings, ErrorLogger *errorLogger)
+        : Check(myName(), tokenizer, settings, errorLogger)
+    {
+    }
+
+    /** @brief Run checks against the simplified token list */
+    void runSimplifiedChecks(const Tokenizer *tokenizer, const Settings *settings, ErrorLogger *errorLogger)
+    {
+        CheckAssignIf checkAssignIf(tokenizer, settings, errorLogger);
+        checkAssignIf.check();
+    }
+
+    /** Check for obsolete functions */
+    void check();
+
+private:
+
+    void mismatchError(const Token *tok);
+
+    void getErrorMessages(ErrorLogger *errorLogger, const Settings *settings)
+    {
+        CheckAssignIf c(0, settings, errorLogger);
+        c.mismatchError(0);
+    }
+
+    std::string myName() const
+    {
+        return "match assignment / conditions";
+    }
+
+    std::string classInfo() const
+    {
+        return "Match assignments and conditions:\n"
+               " mismatching assignment and condition";
+    }
+};
+/// @}
+//---------------------------------------------------------------------------
+#endif
+

lib/lib.pri

@@ -4,6 +4,7 @@ LIBS += -L../externals -lpcre
 INCLUDEPATH += ../externals ../externals/tinyxml
 HEADERS += $${BASEPATH}check.h \
            $${BASEPATH}check64bit.h \
+           $${BASEPATH}checkassignif.h \
            $${BASEPATH}checkautovariables.h \
            $${BASEPATH}checkbufferoverrun.h \
            $${BASEPATH}checkclass.h \
@@ -30,6 +31,7 @@ HEADERS += $${BASEPATH}check.h \
            $${BASEPATH}tokenize.h
 
 SOURCES += $${BASEPATH}check64bit.cpp \
+           $${BASEPATH}checkassignif.cpp \
            $${BASEPATH}checkautovariables.cpp \
            $${BASEPATH}checkbufferoverrun.cpp \
            $${BASEPATH}checkclass.cpp \

test/testassignif.cpp

@@ -0,0 +1,73 @@
+/*
+ * Cppcheck - A tool for static C/C++ code analysis
+ * Copyright (C) 2007-2011 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 "tokenize.h"
+#include "checkassignif.h"
+#include "testsuite.h"
+#include <sstream>
+
+extern std::ostringstream errout;
+
+class TestAssignIf : public TestFixture
+{
+public:
+    TestAssignIf() : TestFixture("TestAssignIf")
+    { }
+
+private:
+
+
+    void run()
+    {
+        TEST_CASE(testand);
+    }
+
+    void check(const char code[])
+    {
+        // Clear the error buffer..
+        errout.str("");
+
+        Settings settings;
+        settings._checkCodingStyle = true;
+
+        // Tokenize..
+        Tokenizer tokenizer(&settings, this);
+        std::istringstream istr(code);
+        tokenizer.tokenize(istr, "test.cpp");
+        tokenizer.setVarId();
+        tokenizer.simplifyTokenList();
+
+        // Check char variable usage..
+        CheckAssignIf CheckAssignIf(&tokenizer, &settings, this);
+        CheckAssignIf.check();
+    }
+
+    void testand()
+    {
+        check("void foo(int x)\n"
+              "{\n"
+              "    int y = x & 4;\n"
+              "    if (y == 3);\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:4]: (style) Mismatching assignment and condition, condition is always false\n", errout.str());
+    }
+};
+
+REGISTER_TEST(TestAssignIf)
+