Null pointers: Broke out the checking into separate file

Makefile

@@ -27,6 +27,7 @@ LIBOBJ =     lib/checkautovariables.o \
               lib/checkclass.o \
               lib/checkexceptionsafety.o \
               lib/checkmemoryleak.o \
+              lib/checknullpointer.o \
               lib/checkobsoletefunctions.o \
               lib/checkother.o \
               lib/checkpostfixoperator.o \
@@ -64,6 +65,7 @@ TESTOBJ =     test/options.o \
               test/testincompletestatement.o \
               test/testmathlib.o \
               test/testmemleak.o \
+              test/testnullpointer.o \
               test/testobsoletefunctions.o \
               test/testoptions.o \
               test/testother.o \
@@ -140,10 +142,13 @@ lib/checkexceptionsafety.o: lib/checkexceptionsafety.cpp lib/checkexceptionsafet
 lib/checkmemoryleak.o: lib/checkmemoryleak.cpp lib/checkmemoryleak.h lib/check.h lib/token.h lib/tokenize.h lib/settings.h lib/errorlogger.h lib/mathlib.h lib/executionpath.h
 	$(CXX) $(CXXFLAGS) -Ilib -c -o lib/checkmemoryleak.o lib/checkmemoryleak.cpp
 
+lib/checknullpointer.o: lib/checknullpointer.cpp lib/checknullpointer.h lib/check.h lib/token.h lib/tokenize.h lib/settings.h lib/errorlogger.h lib/executionpath.h lib/mathlib.h
+	$(CXX) $(CXXFLAGS) -Ilib -c -o lib/checknullpointer.o lib/checknullpointer.cpp
+
 lib/checkobsoletefunctions.o: lib/checkobsoletefunctions.cpp lib/checkobsoletefunctions.h lib/check.h lib/token.h lib/tokenize.h lib/settings.h lib/errorlogger.h
 	$(CXX) $(CXXFLAGS) -Ilib -c -o lib/checkobsoletefunctions.o lib/checkobsoletefunctions.cpp
 
-lib/checkother.o: lib/checkother.cpp lib/checkother.h lib/check.h lib/token.h lib/tokenize.h lib/settings.h lib/errorlogger.h lib/mathlib.h lib/executionpath.h
+lib/checkother.o: lib/checkother.cpp lib/checkother.h lib/check.h lib/token.h lib/tokenize.h lib/settings.h lib/errorlogger.h lib/mathlib.h lib/executionpath.h lib/checknullpointer.h
 	$(CXX) $(CXXFLAGS) -Ilib -c -o lib/checkother.o lib/checkother.cpp
 
 lib/checkpostfixoperator.o: lib/checkpostfixoperator.cpp lib/checkpostfixoperator.h lib/check.h lib/token.h lib/tokenize.h lib/settings.h lib/errorlogger.h
@@ -245,6 +250,9 @@ test/testmathlib.o: test/testmathlib.cpp lib/mathlib.h test/testsuite.h lib/erro
 test/testmemleak.o: test/testmemleak.cpp lib/tokenize.h lib/checkmemoryleak.h lib/check.h lib/token.h lib/settings.h lib/errorlogger.h test/testsuite.h test/redirect.h
 	$(CXX) $(CXXFLAGS) -Ilib -Icli -c -o test/testmemleak.o test/testmemleak.cpp
 
+test/testnullpointer.o: test/testnullpointer.cpp lib/tokenize.h lib/checknullpointer.h lib/check.h lib/token.h lib/settings.h lib/errorlogger.h test/testsuite.h test/redirect.h
+	$(CXX) $(CXXFLAGS) -Ilib -Icli -c -o test/testnullpointer.o test/testnullpointer.cpp
+
 test/testobsoletefunctions.o: test/testobsoletefunctions.cpp lib/tokenize.h lib/checkobsoletefunctions.h lib/check.h lib/token.h lib/settings.h lib/errorlogger.h test/testsuite.h test/redirect.h
 	$(CXX) $(CXXFLAGS) -Ilib -Icli -c -o test/testobsoletefunctions.o test/testobsoletefunctions.cpp
 

lib/checknullpointer.cpp

@@ -0,0 +1,773 @@
+/*
+ * Cppcheck - A tool for static C/C++ code analysis
+ * Copyright (C) 2007-2010 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 "checknullpointer.h"
+#include "executionpath.h"
+#include "mathlib.h"
+//---------------------------------------------------------------------------
+
+// Register this check class (by creating a static instance of it)
+namespace
+{
+CheckNullPointer instance;
+}
+
+//---------------------------------------------------------------------------
+
+
+
+/**
+ * @brief parse a function call and extract information about variable usage
+ * @param tok first token
+ * @param var variables that the function read / write.
+ * @param value 0 => invalid with null pointers as parameter.
+ *              1-.. => invalid with uninitialized data.
+ */
+void CheckNullPointer::parseFunctionCall(const Token &tok, std::list<const Token *> &var, unsigned char value)
+{
+    // standard functions that dereference first parameter..
+    // both uninitialized data and null pointers are invalid.
+    static std::set<std::string> functionNames1;
+    if (functionNames1.empty())
+    {
+        functionNames1.insert("memchr");
+        functionNames1.insert("memcmp");
+        functionNames1.insert("strcat");
+        functionNames1.insert("strncat");
+        functionNames1.insert("strchr");
+        functionNames1.insert("strrchr");
+        functionNames1.insert("strcmp");
+        functionNames1.insert("strncmp");
+        functionNames1.insert("strdup");
+        functionNames1.insert("strndup");
+        functionNames1.insert("strlen");
+        functionNames1.insert("strstr");
+    }
+
+    // standard functions that dereference second parameter..
+    // both uninitialized data and null pointers are invalid.
+    static std::set<std::string> functionNames2;
+    if (functionNames2.empty())
+    {
+        functionNames2.insert("memcmp");
+        functionNames2.insert("memcpy");
+        functionNames2.insert("memmove");
+        functionNames2.insert("strcat");
+        functionNames2.insert("strncat");
+        functionNames2.insert("strcmp");
+        functionNames2.insert("strncmp");
+        functionNames2.insert("strcpy");
+        functionNames2.insert("strncpy");
+        functionNames2.insert("strstr");
+    }
+
+    // 1st parameter..
+    if (Token::Match(&tok, "%var% ( %var% ,|)") && tok.tokAt(2)->varId() > 0)
+    {
+        if (functionNames1.find(tok.str()) != functionNames1.end())
+            var.push_back(tok.tokAt(2));
+        else if (value == 0 && Token::Match(&tok, "memchr|memcmp|memcpy|memmove|memset|strcpy|printf|sprintf|snprintf"))
+            var.push_back(tok.tokAt(2));
+        else if (Token::simpleMatch(&tok, "fflush"))
+            var.push_back(tok.tokAt(2));
+    }
+
+    // 2nd parameter..
+    if (Token::Match(&tok, "%var% ( %any% , %var% ,|)") && tok.tokAt(4)->varId() > 0)
+    {
+        if (functionNames2.find(tok.str()) != functionNames2.end())
+            var.push_back(tok.tokAt(4));
+    }
+}
+
+
+
+void CheckNullPointer::nullPointerAfterLoop()
+{
+    // Locate insufficient null-pointer handling after loop
+    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
+    {
+        if (! Token::Match(tok, "while ( %var% )"))
+            continue;
+
+        const unsigned int varid(tok->tokAt(2)->varId());
+        if (varid == 0)
+            continue;
+
+        const std::string varname(tok->strAt(2));
+
+        // Locate the end of the while loop..
+        const Token *tok2 = tok->tokAt(4);
+        if (tok2->str() == "{")
+            tok2 = tok2->link();
+        else
+        {
+            while (tok2 && tok2->str() != ";")
+                tok2 = tok2->next();
+        }
+
+        // Goto next token
+        if (tok2)
+            tok2 = tok2->next();
+
+        // Check if the variable is dereferenced..
+        while (tok2)
+        {
+            if (tok2->str() == "{" || tok2->str() == "}" || tok2->str() == "break")
+                break;
+
+            if (tok2->varId() == varid)
+            {
+                if (tok2->next()->str() == "." || Token::Match(tok2->next(), "= %varid% .", varid))
+                {
+                    // Is this variable a pointer?
+                    const Token *tok3 = Token::findmatch(_tokenizer->tokens(), "%type% * %varid% [;)=]", varid);
+                    if (!tok3)
+                        break;
+
+                    if (!tok3->previous() ||
+                        Token::Match(tok3->previous(), "[({};]") ||
+                        tok3->previous()->isName())
+                    {
+                        nullPointerError(tok2, varname);
+                    }
+                }
+                break;
+            }
+
+            tok2 = tok2->next();
+        }
+    }
+}
+
+void CheckNullPointer::nullPointerLinkedList()
+{
+    // looping through items in a linked list in a inner loop..
+    for (const Token *tok1 = _tokenizer->tokens(); tok1; tok1 = tok1->next())
+    {
+        // search for a "for" token..
+        if (!Token::simpleMatch(tok1, "for ("))
+            continue;
+
+        if (!Token::simpleMatch(tok1->next()->link(), ") {"))
+            continue;
+
+        // is there any dereferencing occuring in the for statement..
+        unsigned int parlevel2 = 1;
+        for (const Token *tok2 = tok1->tokAt(2); tok2; tok2 = tok2->next())
+        {
+            // Parantheses..
+            if (tok2->str() == "(")
+                ++parlevel2;
+            else if (tok2->str() == ")")
+            {
+                if (parlevel2 <= 1)
+                    break;
+                --parlevel2;
+            }
+
+            // Dereferencing a variable inside the "for" parantheses..
+            else if (Token::Match(tok2, "%var% . %var%"))
+            {
+                const unsigned int varid(tok2->varId());
+                if (varid == 0)
+                    continue;
+
+                if (Token::Match(tok2->tokAt(-2), "%varid% ?", varid))
+                    continue;
+
+                const std::string varname(tok2->str());
+
+                // Check usage of dereferenced variable in the loop..
+                unsigned int indentlevel3 = 0;
+                for (const Token *tok3 = tok1->next()->link(); tok3; tok3 = tok3->next())
+                {
+                    if (tok3->str() == "{")
+                        ++indentlevel3;
+                    else if (tok3->str() == "}")
+                    {
+                        if (indentlevel3 <= 1)
+                            break;
+                        --indentlevel3;
+                    }
+                    else if (Token::Match(tok3, "while ( %varid% &&|)", varid))
+                    {
+                        // Make sure there is a "break" to prevent segmentation faults..
+                        unsigned int indentlevel4 = indentlevel3;
+                        for (const Token *tok4 = tok3->next()->link(); tok4; tok4 = tok4->next())
+                        {
+                            if (tok4->str() == "{")
+                                ++indentlevel4;
+                            else if (tok4->str() == "}")
+                            {
+                                if (indentlevel4 <= 1)
+                                {
+                                    // Is this variable a pointer?
+                                    const Token *tempTok = Token::findmatch(_tokenizer->tokens(), "%type% * %varid% [;)=]", varid);
+                                    if (tempTok)
+                                        nullPointerError(tok1, varname, tok3->linenr());
+
+                                    break;
+                                }
+                                --indentlevel4;
+                            }
+                            else if (tok4->str() == "break" || tok4->str() == "return")
+                                break;
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
+void CheckNullPointer::nullPointerStructByDeRefAndChec()
+{
+    // don't check vars that has been tested against null already
+    std::set<unsigned int> skipvar;
+    skipvar.insert(0);
+
+    // Dereferencing a struct pointer and then checking if it's NULL..
+    for (const Token *tok1 = _tokenizer->tokens(); tok1; tok1 = tok1->next())
+    {
+        if (Token::Match(tok1, "if|while ( !| %var% )"))
+        {
+            tok1 = tok1->tokAt(2);
+            if (tok1->str() == "!")
+                tok1 = tok1->next();
+            skipvar.insert(tok1->varId());
+            continue;
+        }
+
+        // dereference in assignment
+        if (Token::Match(tok1, "[{};] %var% = %var% . %var%"))
+        {
+            if (std::string(tok1->strAt(1)) == tok1->strAt(3))
+                continue;
+            tok1 = tok1->tokAt(3);
+        }
+
+        // dereference in function call
+        else if (Token::Match(tok1->tokAt(-2), "%var% ( %var% . %var%") ||
+                 Token::Match(tok1->previous(), ", %var% . %var%"))
+        {
+
+        }
+
+        // Goto next token
+        else
+        {
+            continue;
+        }
+
+        // struct dereference was found - investigate if it is later
+        // checked that it is not NULL
+        const unsigned int varid1(tok1->varId());
+        if (skipvar.find(varid1) != skipvar.end())
+            continue;
+
+        const std::string varname(tok1->str());
+
+        unsigned int indentlevel2 = 0;
+        for (const Token *tok2 = tok1->tokAt(3); tok2; tok2 = tok2->next())
+        {
+            if (tok2->str() == "{")
+                ++indentlevel2;
+
+            else if (tok2->str() == "}")
+            {
+                if (indentlevel2 <= 1)
+                    break;
+                --indentlevel2;
+            }
+
+            // goto destination..
+            else if (tok2->isName() && Token::simpleMatch(tok2->next(), ":"))
+                break;
+
+            // Reassignment of the struct
+            else if (tok2->varId() == varid1)
+            {
+                if (tok2->next()->str() == "=")
+                    break;
+                if (Token::Match(tok2->tokAt(-2), "[,(] &"))
+                    break;
+            }
+
+            // Loop..
+            /** @todo don't bail out if the variable is not used in the loop */
+            else if (tok2->str() == "do")
+                break;
+
+            // return at base level => stop checking
+            else if (indentlevel2 == 0 && tok2->str() == "return")
+                break;
+
+            else if (Token::Match(tok2, "if ( !| %varid% )", varid1))
+            {
+                // Is this variable a pointer?
+                const Token *tempTok = Token::findmatch(_tokenizer->tokens(), "%type% * %varid% [;)=]", varid1);
+                if (tempTok)
+                    nullPointerError(tok1, varname, tok2->linenr());
+                break;
+            }
+        }
+    }
+}
+
+void CheckNullPointer::nullPointerByDeRefAndChec()
+{
+    // Dereferencing a pointer and then checking if it's NULL..
+    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
+    {
+        if (tok->str() == "if" && Token::Match(tok->previous(), "; if ( ! %var% )"))
+        {
+            const unsigned int varid(tok->tokAt(3)->varId());
+            if (varid == 0)
+                continue;
+
+            const std::string varname(tok->strAt(3));
+
+            // Check that variable is a pointer..
+            const Token *decltok = Token::findmatch(_tokenizer->tokens(), "%varid%", varid);
+            if (!Token::Match(decltok->tokAt(-3), "[{};,(] %type% *"))
+                continue;
+
+            for (const Token *tok1 = tok->previous(); tok1 && tok1 != decltok; tok1 = tok1->previous())
+            {
+                if (tok1->varId() == varid)
+                {
+                    if (Token::Match(tok1->tokAt(-2), "[=;{}] *"))
+                    {
+                        nullPointerError(tok1, varname, tok->linenr());
+                        break;
+                    }
+                    else if (Token::simpleMatch(tok1->previous(), "&"))
+                    {
+                        break;
+                    }
+                    else if (Token::simpleMatch(tok1->next(), "="))
+                    {
+                        break;
+                    }
+                    // dereference in function call
+                    else if (Token::Match(tok1->tokAt(-3), "!!sizeof [(,] *"))
+                    {
+                        nullPointerError(tok1, varname, tok->linenr());
+                    }
+                }
+
+                else if (tok1->str() == "{" ||
+                         tok1->str() == "}")
+                    break;
+
+                // label..
+                else if (Token::Match(tok1, "%type% :"))
+                    break;
+            }
+        }
+    }
+}
+
+void CheckNullPointer::nullPointerByCheckAndDeRef()
+{
+    // Check if pointer is NULL and then dereference it..
+    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
+    {
+        if (Token::Match(tok, "if ( ! %var% ) {"))
+        {
+            bool null = true;
+            const unsigned int varid(tok->tokAt(3)->varId());
+            if (varid == 0)
+                continue;
+            unsigned int indentlevel = 1;
+            for (const Token *tok2 = tok->tokAt(6); tok2; tok2 = tok2->next())
+            {
+                if (tok2->str() == "{")
+                    ++indentlevel;
+                else if (tok2->str() == "}")
+                {
+                    if (indentlevel == 0)
+                        break;
+                    --indentlevel;
+                    if (null && indentlevel == 0)
+                    {
+                        // skip all "else" blocks because they are not executed in this execution path
+                        while (Token::Match(tok2, "} else {"))
+                            tok2 = tok2->tokAt(2)->link();
+                        null = false;
+                    }
+                }
+
+                if (Token::Match(tok2, "goto|return|continue|break|throw|if"))
+                {
+                    if (Token::Match(tok2, "return * %var%"))
+                        nullPointerError(tok2, tok->strAt(3));
+                    break;
+                }
+
+                // abort function..
+                if (Token::Match(tok2->previous(), "[;{}] %var% (") &&
+                    Token::simpleMatch(tok2->next()->link(), ") ; }"))
+                {
+                    break;
+                }
+
+                if (tok2->varId() == varid)
+                {
+                    if (Token::Match(tok2->previous(), "[;{}=] %var% = 0 ;"))
+                        ;
+
+                    else if (Token::Match(tok2->tokAt(-2), "[;{}=+-/(,] * %var%"))
+                        nullPointerError(tok2, tok->strAt(3));
+
+                    else if (!Token::simpleMatch(tok2->tokAt(-2), "& (") && Token::Match(tok2->next(), ". %var%"))
+                        nullPointerError(tok2, tok->strAt(3));
+
+                    else if (Token::Match(tok2->previous(), "[;{}=+-/(,] %var% [ %any% ]"))
+                        nullPointerError(tok2, tok->strAt(3));
+
+                    else if (Token::Match(tok2->previous(), "return %var% [ %any% ]"))
+                        nullPointerError(tok2, tok->strAt(3));
+
+                    else if (Token::Match(tok2, "%var% ("))
+                        nullPointerError(tok2, tok->strAt(3));
+
+                    else
+                        break;
+                }
+            }
+        }
+    }
+}
+
+
+void CheckNullPointer::nullPointer()
+{
+    nullPointerAfterLoop();
+    nullPointerLinkedList();
+    nullPointerStructByDeRefAndChec();
+    nullPointerByDeRefAndChec();
+    nullPointerByCheckAndDeRef();
+}
+
+/** Derefencing null constant (simplified token list) */
+void CheckNullPointer::nullConstantDereference()
+{
+    // this is kept at 0 for all scopes that are not executing
+    unsigned int indentlevel = 0;
+
+    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
+    {
+        // start of executable scope..
+        if (indentlevel == 0 && Token::Match(tok, ") const| {"))
+            indentlevel = 1;
+
+        else if (indentlevel >= 1)
+        {
+            if (tok->str() == "{")
+                ++indentlevel;
+
+            else if (tok->str() == "}")
+            {
+                if (indentlevel <= 2)
+                    indentlevel = 0;
+                else
+                    --indentlevel;
+            }
+
+            if (tok->str() == "(" && Token::simpleMatch(tok->previous(), "sizeof"))
+                tok = tok->link();
+
+            else if (Token::simpleMatch(tok, "exit ( )"))
+            {
+                // Goto end of scope
+                while (tok && tok->str() != "}")
+                {
+                    if (tok->str() == "{")
+                        tok = tok->link();
+                    tok = tok->next();
+                }
+                if (!tok)
+                    break;
+            }
+
+            else if (Token::simpleMatch(tok, "* 0"))
+            {
+                if (Token::Match(tok->previous(), "[<>;{}=+-*/(,]") ||
+                    Token::Match(tok->previous(), "return|<<"))
+                {
+                    nullPointerError(tok);
+                }
+            }
+        }
+    }
+}
+
+
+/// @addtogroup Checks
+/// @{
+
+
+/**
+ * @brief %Check for null pointer usage (using ExecutionPath)
+ */
+
+class Nullpointer : public ExecutionPath
+{
+public:
+    /** Startup constructor */
+    Nullpointer(Check *c) : ExecutionPath(c, 0), null(false)
+    {
+    }
+
+private:
+    /** Create checking of specific variable: */
+    Nullpointer(Check *c, const unsigned int id, const std::string &name)
+        : ExecutionPath(c, id),
+          varname(name),
+          null(false)
+    {
+    }
+
+    /** Copy this check */
+    ExecutionPath *copy()
+    {
+        return new Nullpointer(*this);
+    }
+
+    /** no implementation => compiler error if used by accident */
+    void operator=(const Nullpointer &);
+
+    /** is other execution path equal? */
+    bool is_equal(const ExecutionPath *e) const
+    {
+        const Nullpointer *c = static_cast<const Nullpointer *>(e);
+        return (varname == c->varname && null == c->null);
+    }
+
+    /** variable name for this check (empty => dummy check) */
+    const std::string varname;
+
+    /** is this variable null? */
+    bool null;
+
+    /** variable is set to null */
+    static void setnull(std::list<ExecutionPath *> &checks, const unsigned int varid)
+    {
+        std::list<ExecutionPath *>::iterator it;
+        for (it = checks.begin(); it != checks.end(); ++it)
+        {
+            Nullpointer *c = dynamic_cast<Nullpointer *>(*it);
+            if (c && c->varId == varid)
+                c->null = true;
+        }
+    }
+
+    /**
+     * Dereferencing variable. Check if it is safe (if the variable is null there's an error)
+     * @param checks Checks
+     * @param tok token where dereferencing happens
+     */
+    static void dereference(std::list<ExecutionPath *> &checks, const Token *tok)
+    {
+        const unsigned int varid(tok->varId());
+
+        std::list<ExecutionPath *>::iterator it;
+        for (it = checks.begin(); it != checks.end(); ++it)
+        {
+            Nullpointer *c = dynamic_cast<Nullpointer *>(*it);
+            if (c && c->varId == varid && c->null)
+            {
+                CheckNullPointer *checkNullPointer = dynamic_cast<CheckNullPointer *>(c->owner);
+                if (checkNullPointer)
+                {
+                    checkNullPointer->nullPointerError(tok, c->varname);
+                    return;
+                }
+            }
+        }
+    }
+
+    /** parse tokens */
+    const Token *parse(const Token &tok, std::list<ExecutionPath *> &checks) const
+    {
+        if (Token::Match(tok.previous(), "[;{}] const| %type% * %var% ;"))
+        {
+            const Token * vartok = tok.tokAt(2);
+
+            if (tok.str() == "const")
+                vartok = vartok->next();
+
+            if (vartok->varId() != 0)
+                checks.push_back(new Nullpointer(owner, vartok->varId(), vartok->str()));
+            return vartok->next();
+        }
+
+        // Template pointer variable..
+        if (Token::Match(tok.previous(), "[;{}] %type% ::|<"))
+        {
+            const Token * vartok = &tok;
+            while (Token::Match(vartok, "%type% ::"))
+                vartok = vartok->tokAt(2);
+            if (Token::Match(vartok, "%type% < %type%"))
+            {
+                vartok = vartok->tokAt(3);
+                while (vartok && (vartok->str() == "*" || vartok->isName()))
+                    vartok = vartok->next();
+            }
+            if (vartok
+                && (vartok->str() == ">" || vartok->isName())
+                && Token::Match(vartok->next(), "* %var% ;|="))
+            {
+                vartok = vartok->tokAt(2);
+                checks.push_back(new Nullpointer(owner, vartok->varId(), vartok->str()));
+                if (Token::simpleMatch(vartok->next(), "= 0 ;"))
+                    setnull(checks, vartok->varId());
+                return vartok->next();
+            }
+        }
+
+        if (Token::simpleMatch(&tok, "try {"))
+        {
+            // Bail out all used variables
+            unsigned int indentlevel = 0;
+            for (const Token *tok2 = &tok; tok2; tok2 = tok2->next())
+            {
+                if (tok2->str() == "{")
+                    ++indentlevel;
+                else if (tok2->str() == "}")
+                {
+                    if (indentlevel == 0)
+                        break;
+                    if (indentlevel == 1 && !Token::simpleMatch(tok2,"} catch ("))
+                        return tok2;
+                    --indentlevel;
+                }
+                else if (tok2->varId())
+                    bailOutVar(checks,tok2->varId());
+            }
+        }
+
+        if (Token::Match(&tok, "%var% ("))
+        {
+            if (tok.str() == "sizeof")
+                return tok.next()->link();
+
+            // parse usage..
+            std::list<const Token *> var;
+            CheckNullPointer::parseFunctionCall(tok, var, 0);
+            for (std::list<const Token *>::const_iterator it = var.begin(); it != var.end(); ++it)
+                dereference(checks, *it);
+        }
+
+        if (tok.varId() != 0)
+        {
+            if (Token::Match(tok.previous(), "[;{}=] %var% = 0 ;"))
+                setnull(checks, tok.varId());
+            else if (Token::Match(tok.tokAt(-2), "[;{}=+-/(,] * %var%"))
+                dereference(checks, &tok);
+            else if (Token::Match(tok.tokAt(-2), "return * %var%"))
+                dereference(checks, &tok);
+            else if (!Token::simpleMatch(tok.tokAt(-2), "& (") && Token::Match(tok.next(), ". %var%"))
+                dereference(checks, &tok);
+            else if (Token::Match(tok.previous(), "[;{}=+-/(,] %var% [ %any% ]"))
+                dereference(checks, &tok);
+            else if (Token::Match(tok.previous(), "return %var% [ %any% ]"))
+                dereference(checks, &tok);
+            else if (Token::Match(&tok, "%var% ("))
+                dereference(checks, &tok);
+            else
+                bailOutVar(checks, tok.varId());
+        }
+
+        else if (tok.str() == "delete")
+        {
+            const Token *ret = tok.next();
+            if (Token::simpleMatch(ret, "[ ]"))
+                ret = ret->tokAt(2);
+            if (Token::Match(ret, "%var% ;"))
+                return ret->next();
+        }
+
+        return &tok;
+    }
+
+    /** parse condition. @sa ExecutionPath::parseCondition */
+    bool parseCondition(const Token &tok, std::list<ExecutionPath *> &checks)
+    {
+        for (const Token *tok2 = &tok; tok2; tok2 = tok2->next())
+        {
+            if (tok2->str() == "(" || tok2->str() == ")")
+                break;
+            if (Token::Match(tok2, "[<>=] * %var%"))
+                dereference(checks, tok2->tokAt(2));
+        }
+
+        if (Token::Match(&tok, "!| %var% ("))
+        {
+            std::list<const Token *> var;
+            CheckNullPointer::parseFunctionCall(tok.str() == "!" ? *tok.next() : tok, var, 0);
+            for (std::list<const Token *>::const_iterator it = var.begin(); it != var.end(); ++it)
+                dereference(checks, *it);
+        }
+
+        return ExecutionPath::parseCondition(tok, checks);
+    }
+
+
+    void parseLoopBody(const Token *tok, std::list<ExecutionPath *> &checks) const
+    {
+        while (tok)
+        {
+            if (Token::Match(tok, "{|}|return|goto|break|if"))
+                return;
+            const Token *next = parse(*tok, checks);
+            if (next)
+                tok = tok->next();
+        }
+    }
+
+};
+/// @}
+
+
+void CheckNullPointer::executionPaths()
+{
+    // Check for null pointer errors..
+    Nullpointer c(this);
+    checkExecutionPaths(_tokenizer->tokens(), &c);
+}
+
+void CheckNullPointer::nullPointerError(const Token *tok)
+{
+    reportError(tok, Severity::error, "nullPointer", "Null pointer dereference");
+}
+
+void CheckNullPointer::nullPointerError(const Token *tok, const std::string &varname)
+{
+    reportError(tok, Severity::error, "nullPointer", "Possible null pointer dereference: " + varname);
+}
+
+void CheckNullPointer::nullPointerError(const Token *tok, const std::string &varname, const unsigned int line)
+{
+    reportError(tok, Severity::error, "nullPointer", "Possible null pointer dereference: " + varname + " - otherwise it is redundant to check if " + varname + " is null at line " + MathLib::toString<unsigned int>(line));
+}
+

lib/checknullpointer.h

@@ -0,0 +1,146 @@
+/*
+ * Cppcheck - A tool for static C/C++ code analysis
+ * Copyright (C) 2007-2010 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 checknullpointerH
+#define checknullpointerH
+//---------------------------------------------------------------------------
+
+#include "check.h"
+#include "settings.h"
+
+class Token;
+
+/// @addtogroup Checks
+/// @{
+
+
+/** @brief check for null pointer dereferencing */
+
+class CheckNullPointer : public Check
+{
+public:
+    /** @brief This constructor is used when registering the CheckNullPointer */
+    CheckNullPointer() : Check()
+    { }
+
+    /** @brief This constructor is used when running checks. */
+    CheckNullPointer(const Tokenizer *tokenizer, const Settings *settings, ErrorLogger *errorLogger)
+        : Check(tokenizer, settings, errorLogger)
+    { }
+
+    /** @brief Run checks against the normal token list */
+    void runChecks(const Tokenizer *tokenizer, const Settings *settings, ErrorLogger *errorLogger)
+    {
+        CheckNullPointer checkNullPointer(tokenizer, settings, errorLogger);
+        checkNullPointer.nullPointer();
+    }
+
+    /** @brief Run checks against the simplified token list */
+    void runSimplifiedChecks(const Tokenizer *tokenizer, const Settings *settings, ErrorLogger *errorLogger)
+    {
+        CheckNullPointer checkNullPointer(tokenizer, settings, errorLogger);
+        checkNullPointer.nullConstantDereference();
+        checkNullPointer.executionPaths();
+    }
+
+    /**
+     * @brief parse a function call and extract information about variable usage
+     * @param tok first token
+     * @param var variables that the function read / write.
+     * @param value 0 => invalid with null pointers as parameter.
+     *              non-zero => invalid with uninitialized data.
+     */
+    static void parseFunctionCall(const Token &tok,
+                                  std::list<const Token *> &var,
+                                  unsigned char value);
+
+    /** @brief possible null pointer dereference */
+    void nullPointer();
+
+    /**
+     * @brief Does one part of the check for nullPointer().
+     * Checking if pointer is NULL and then dereferencing it..
+     */
+    void nullPointerByCheckAndDeRef();
+
+    /** @brief dereferencing null constant (after Tokenizer::simplifyKnownVariables) */
+    void nullConstantDereference();
+
+    /** @brief new type of check: check execution paths */
+    void executionPaths();
+
+    void nullPointerError(const Token *tok);  // variable name unknown / doesn't exist
+    void nullPointerError(const Token *tok, const std::string &varname);
+    void nullPointerError(const Token *tok, const std::string &varname, const unsigned int line);
+
+    void getErrorMessages()
+    {
+        nullPointerError(0, "pointer");
+    }
+
+    std::string name() const
+    {
+        return "Null pointer";
+    }
+
+    std::string classInfo() const
+    {
+        return "Null pointers\n"
+               "* null pointer dereferencing\n";
+    }
+
+private:
+
+    /**
+     * @brief Does one part of the check for nullPointer().
+     * Locate insufficient null-pointer handling after loop
+     */
+    void nullPointerAfterLoop();
+
+    /**
+     * @brief Does one part of the check for nullPointer().
+     * looping through items in a linked list in a inner loop..
+     */
+    void nullPointerLinkedList();
+
+    /**
+     * @brief Does one part of the check for nullPointer().
+     * Dereferencing a struct pointer and then checking if it's NULL..
+     */
+    void nullPointerStructByDeRefAndChec();
+
+    /**
+     * @brief Does one part of the check for nullPointer().
+     * Dereferencing a pointer and then checking if it's NULL..
+     */
+    void nullPointerByDeRefAndChec();
+
+    /**
+     * @brief Does one part of the check for nullPointer().
+     * -# initialize pointer to 0
+     * -# conditionally assign pointer
+     * -# dereference pointer
+     */
+    void nullPointerConditionalAssignment();
+};
+/// @}
+//---------------------------------------------------------------------------
+#endif
+

lib/checkother.cpp

@@ -21,6 +21,7 @@
 #include "checkother.h"
 #include "mathlib.h"
 #include "executionpath.h"
+#include "checknullpointer.h"   // CheckNullPointer::parseFunctionCall
 
 #include <algorithm>
 #include <list>
@@ -2249,719 +2250,9 @@ void CheckOther::strPlusChar()
 }
 
 
-void CheckOther::nullPointerAfterLoop()
-{
-    // Locate insufficient null-pointer handling after loop
-    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
-    {
-        if (! Token::Match(tok, "while ( %var% )"))
-            continue;
-
-        const unsigned int varid(tok->tokAt(2)->varId());
-        if (varid == 0)
-            continue;
-
-        const std::string varname(tok->strAt(2));
-
-        // Locate the end of the while loop..
-        const Token *tok2 = tok->tokAt(4);
-        if (tok2->str() == "{")
-            tok2 = tok2->link();
-        else
-        {
-            while (tok2 && tok2->str() != ";")
-                tok2 = tok2->next();
-        }
-
-        // Goto next token
-        if (tok2)
-            tok2 = tok2->next();
-
-        // Check if the variable is dereferenced..
-        while (tok2)
-        {
-            if (tok2->str() == "{" || tok2->str() == "}" || tok2->str() == "break")
-                break;
-
-            if (tok2->varId() == varid)
-            {
-                if (tok2->next()->str() == "." || Token::Match(tok2->next(), "= %varid% .", varid))
-                {
-                    // Is this variable a pointer?
-                    const Token *tok3 = Token::findmatch(_tokenizer->tokens(), "%type% * %varid% [;)=]", varid);
-                    if (!tok3)
-                        break;
-
-                    if (!tok3->previous() ||
-                        Token::Match(tok3->previous(), "[({};]") ||
-                        tok3->previous()->isName())
-                    {
-                        nullPointerError(tok2, varname);
-                    }
-                }
-                break;
-            }
-
-            tok2 = tok2->next();
-        }
-    }
-}
-
-void CheckOther::nullPointerLinkedList()
-{
-    // looping through items in a linked list in a inner loop..
-    for (const Token *tok1 = _tokenizer->tokens(); tok1; tok1 = tok1->next())
-    {
-        // search for a "for" token..
-        if (!Token::simpleMatch(tok1, "for ("))
-            continue;
-
-        if (!Token::simpleMatch(tok1->next()->link(), ") {"))
-            continue;
-
-        // is there any dereferencing occuring in the for statement..
-        unsigned int parlevel2 = 1;
-        for (const Token *tok2 = tok1->tokAt(2); tok2; tok2 = tok2->next())
-        {
-            // Parantheses..
-            if (tok2->str() == "(")
-                ++parlevel2;
-            else if (tok2->str() == ")")
-            {
-                if (parlevel2 <= 1)
-                    break;
-                --parlevel2;
-            }
-
-            // Dereferencing a variable inside the "for" parantheses..
-            else if (Token::Match(tok2, "%var% . %var%"))
-            {
-                const unsigned int varid(tok2->varId());
-                if (varid == 0)
-                    continue;
-
-                if (Token::Match(tok2->tokAt(-2), "%varid% ?", varid))
-                    continue;
-
-                const std::string varname(tok2->str());
-
-                // Check usage of dereferenced variable in the loop..
-                unsigned int indentlevel3 = 0;
-                for (const Token *tok3 = tok1->next()->link(); tok3; tok3 = tok3->next())
-                {
-                    if (tok3->str() == "{")
-                        ++indentlevel3;
-                    else if (tok3->str() == "}")
-                    {
-                        if (indentlevel3 <= 1)
-                            break;
-                        --indentlevel3;
-                    }
-                    else if (Token::Match(tok3, "while ( %varid% &&|)", varid))
-                    {
-                        // Make sure there is a "break" to prevent segmentation faults..
-                        unsigned int indentlevel4 = indentlevel3;
-                        for (const Token *tok4 = tok3->next()->link(); tok4; tok4 = tok4->next())
-                        {
-                            if (tok4->str() == "{")
-                                ++indentlevel4;
-                            else if (tok4->str() == "}")
-                            {
-                                if (indentlevel4 <= 1)
-                                {
-                                    // Is this variable a pointer?
-                                    const Token *tempTok = Token::findmatch(_tokenizer->tokens(), "%type% * %varid% [;)=]", varid);
-                                    if (tempTok)
-                                        nullPointerError(tok1, varname, tok3->linenr());
-
-                                    break;
-                                }
-                                --indentlevel4;
-                            }
-                            else if (tok4->str() == "break" || tok4->str() == "return")
-                                break;
-                        }
-                    }
-                }
-            }
-        }
-    }
-}
-
-void CheckOther::nullPointerStructByDeRefAndChec()
-{
-    // don't check vars that has been tested against null already
-    std::set<unsigned int> skipvar;
-    skipvar.insert(0);
-
-    // Dereferencing a struct pointer and then checking if it's NULL..
-    for (const Token *tok1 = _tokenizer->tokens(); tok1; tok1 = tok1->next())
-    {
-        if (Token::Match(tok1, "if|while ( !| %var% )"))
-        {
-            tok1 = tok1->tokAt(2);
-            if (tok1->str() == "!")
-                tok1 = tok1->next();
-            skipvar.insert(tok1->varId());
-            continue;
-        }
-
-        // dereference in assignment
-        if (Token::Match(tok1, "[{};] %var% = %var% . %var%"))
-        {
-            if (std::string(tok1->strAt(1)) == tok1->strAt(3))
-                continue;
-            tok1 = tok1->tokAt(3);
-        }
-
-        // dereference in function call
-        else if (Token::Match(tok1->tokAt(-2), "%var% ( %var% . %var%") ||
-                 Token::Match(tok1->previous(), ", %var% . %var%"))
-        {
-
-        }
-
-        // Goto next token
-        else
-        {
-            continue;
-        }
-
-        // struct dereference was found - investigate if it is later
-        // checked that it is not NULL
-        const unsigned int varid1(tok1->varId());
-        if (skipvar.find(varid1) != skipvar.end())
-            continue;
-
-        const std::string varname(tok1->str());
-
-        unsigned int indentlevel2 = 0;
-        for (const Token *tok2 = tok1->tokAt(3); tok2; tok2 = tok2->next())
-        {
-            if (tok2->str() == "{")
-                ++indentlevel2;
-
-            else if (tok2->str() == "}")
-            {
-                if (indentlevel2 <= 1)
-                    break;
-                --indentlevel2;
-            }
-
-            // goto destination..
-            else if (tok2->isName() && Token::simpleMatch(tok2->next(), ":"))
-                break;
-
-            // Reassignment of the struct
-            else if (tok2->varId() == varid1)
-            {
-                if (tok2->next()->str() == "=")
-                    break;
-                if (Token::Match(tok2->tokAt(-2), "[,(] &"))
-                    break;
-            }
-
-            // Loop..
-            /** @todo don't bail out if the variable is not used in the loop */
-            else if (tok2->str() == "do")
-                break;
-
-            // return at base level => stop checking
-            else if (indentlevel2 == 0 && tok2->str() == "return")
-                break;
-
-            else if (Token::Match(tok2, "if ( !| %varid% )", varid1))
-            {
-                // Is this variable a pointer?
-                const Token *tempTok = Token::findmatch(_tokenizer->tokens(), "%type% * %varid% [;)=]", varid1);
-                if (tempTok)
-                    nullPointerError(tok1, varname, tok2->linenr());
-                break;
-            }
-        }
-    }
-}
-
-void CheckOther::nullPointerByDeRefAndChec()
-{
-    // Dereferencing a pointer and then checking if it's NULL..
-    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
-    {
-        if (tok->str() == "if" && Token::Match(tok->previous(), "; if ( ! %var% )"))
-        {
-            const unsigned int varid(tok->tokAt(3)->varId());
-            if (varid == 0)
-                continue;
-
-            const std::string varname(tok->strAt(3));
-
-            // Check that variable is a pointer..
-            const Token *decltok = Token::findmatch(_tokenizer->tokens(), "%varid%", varid);
-            if (!Token::Match(decltok->tokAt(-3), "[{};,(] %type% *"))
-                continue;
-
-            for (const Token *tok1 = tok->previous(); tok1 && tok1 != decltok; tok1 = tok1->previous())
-            {
-                if (tok1->varId() == varid)
-                {
-                    if (Token::Match(tok1->tokAt(-2), "[=;{}] *"))
-                    {
-                        nullPointerError(tok1, varname, tok->linenr());
-                        break;
-                    }
-                    else if (Token::simpleMatch(tok1->previous(), "&"))
-                    {
-                        break;
-                    }
-                    else if (Token::simpleMatch(tok1->next(), "="))
-                    {
-                        break;
-                    }
-                    // dereference in function call
-                    else if (Token::Match(tok1->tokAt(-3), "!!sizeof [(,] *"))
-                    {
-                        nullPointerError(tok1, varname, tok->linenr());
-                    }
-                }
-
-                else if (tok1->str() == "{" ||
-                         tok1->str() == "}")
-                    break;
-
-                // label..
-                else if (Token::Match(tok1, "%type% :"))
-                    break;
-            }
-        }
-    }
-}
-
-void CheckOther::nullPointerByCheckAndDeRef()
-{
-    // Check if pointer is NULL and then dereference it..
-    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
-    {
-        if (Token::Match(tok, "if ( ! %var% ) {"))
-        {
-            bool null = true;
-            const unsigned int varid(tok->tokAt(3)->varId());
-            if (varid == 0)
-                continue;
-            unsigned int indentlevel = 1;
-            for (const Token *tok2 = tok->tokAt(6); tok2; tok2 = tok2->next())
-            {
-                if (tok2->str() == "{")
-                    ++indentlevel;
-                else if (tok2->str() == "}")
-                {
-                    if (indentlevel == 0)
-                        break;
-                    --indentlevel;
-                    if (null && indentlevel == 0)
-                    {
-                        // skip all "else" blocks because they are not executed in this execution path
-                        while (Token::Match(tok2, "} else {"))
-                            tok2 = tok2->tokAt(2)->link();
-                        null = false;
-                    }
-                }
-
-                if (Token::Match(tok2, "goto|return|continue|break|throw|if"))
-                {
-                    if (Token::Match(tok2, "return * %var%"))
-                        nullPointerError(tok2, tok->strAt(3));
-                    break;
-                }
-
-                // abort function..
-                if (Token::Match(tok2->previous(), "[;{}] %var% (") &&
-                    Token::simpleMatch(tok2->next()->link(), ") ; }"))
-                {
-                    break;
-                }
-
-                if (tok2->varId() == varid)
-                {
-                    if (Token::Match(tok2->previous(), "[;{}=] %var% = 0 ;"))
-                        ;
-
-                    else if (Token::Match(tok2->tokAt(-2), "[;{}=+-/(,] * %var%"))
-                        nullPointerError(tok2, tok->strAt(3));
-
-                    else if (!Token::simpleMatch(tok2->tokAt(-2), "& (") && Token::Match(tok2->next(), ". %var%"))
-                        nullPointerError(tok2, tok->strAt(3));
-
-                    else if (Token::Match(tok2->previous(), "[;{}=+-/(,] %var% [ %any% ]"))
-                        nullPointerError(tok2, tok->strAt(3));
-
-                    else if (Token::Match(tok2->previous(), "return %var% [ %any% ]"))
-                        nullPointerError(tok2, tok->strAt(3));
-
-                    else if (Token::Match(tok2, "%var% ("))
-                        nullPointerError(tok2, tok->strAt(3));
-
-                    else
-                        break;
-                }
-            }
-        }
-    }
-}
-
-
-void CheckOther::nullPointer()
-{
-    nullPointerAfterLoop();
-    nullPointerLinkedList();
-    nullPointerStructByDeRefAndChec();
-    nullPointerByDeRefAndChec();
-    nullPointerByCheckAndDeRef();
-}
-
-/** Derefencing null constant (simplified token list) */
-void CheckOther::nullConstantDereference()
-{
-    // this is kept at 0 for all scopes that are not executing
-    unsigned int indentlevel = 0;
-
-    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
-    {
-        // start of executable scope..
-        if (indentlevel == 0 && Token::Match(tok, ") const| {"))
-            indentlevel = 1;
-
-        else if (indentlevel >= 1)
-        {
-            if (tok->str() == "{")
-                ++indentlevel;
-
-            else if (tok->str() == "}")
-            {
-                if (indentlevel <= 2)
-                    indentlevel = 0;
-                else
-                    --indentlevel;
-            }
-
-            if (tok->str() == "(" && Token::simpleMatch(tok->previous(), "sizeof"))
-                tok = tok->link();
-
-            else if (Token::simpleMatch(tok, "exit ( )"))
-            {
-                // Goto end of scope
-                while (tok && tok->str() != "}")
-                {
-                    if (tok->str() == "{")
-                        tok = tok->link();
-                    tok = tok->next();
-                }
-                if (!tok)
-                    break;
-            }
-
-            else if (Token::simpleMatch(tok, "* 0"))
-            {
-                if (Token::Match(tok->previous(), "[<>;{}=+-*/(,]") ||
-                    Token::Match(tok->previous(), "return|<<"))
-                {
-                    nullPointerError(tok);
-                }
-            }
-        }
-    }
-}
-
-/**
- * \brief parse a function call and extract information about variable usage
- * \param tok first token
- * \param var variables that the function read / write.
- * \param value 0 => invalid with null pointers as parameter.
- *              1-.. => invalid with uninitialized data.
- */
-static void parseFunctionCall(const Token &tok, std::list<const Token *> &var, unsigned char value)
-{
-    // standard functions that dereference first parameter..
-    // both uninitialized data and null pointers are invalid.
-    static std::set<std::string> functionNames1;
-    if (functionNames1.empty())
-    {
-        functionNames1.insert("memchr");
-        functionNames1.insert("memcmp");
-        functionNames1.insert("strcat");
-        functionNames1.insert("strncat");
-        functionNames1.insert("strchr");
-        functionNames1.insert("strrchr");
-        functionNames1.insert("strcmp");
-        functionNames1.insert("strncmp");
-        functionNames1.insert("strdup");
-        functionNames1.insert("strndup");
-        functionNames1.insert("strlen");
-        functionNames1.insert("strstr");
-    }
-
-    // standard functions that dereference second parameter..
-    // both uninitialized data and null pointers are invalid.
-    static std::set<std::string> functionNames2;
-    if (functionNames2.empty())
-    {
-        functionNames2.insert("memcmp");
-        functionNames2.insert("memcpy");
-        functionNames2.insert("memmove");
-        functionNames2.insert("strcat");
-        functionNames2.insert("strncat");
-        functionNames2.insert("strcmp");
-        functionNames2.insert("strncmp");
-        functionNames2.insert("strcpy");
-        functionNames2.insert("strncpy");
-        functionNames2.insert("strstr");
-    }
-
-    // 1st parameter..
-    if (Token::Match(&tok, "%var% ( %var% ,|)") && tok.tokAt(2)->varId() > 0)
-    {
-        if (functionNames1.find(tok.str()) != functionNames1.end())
-            var.push_back(tok.tokAt(2));
-        else if (value == 0 && Token::Match(&tok, "memchr|memcmp|memcpy|memmove|memset|strcpy|printf|sprintf|snprintf"))
-            var.push_back(tok.tokAt(2));
-        else if (Token::simpleMatch(&tok, "fflush"))
-            var.push_back(tok.tokAt(2));
-    }
-
-    // 2nd parameter..
-    if (Token::Match(&tok, "%var% ( %any% , %var% ,|)") && tok.tokAt(4)->varId() > 0)
-    {
-        if (functionNames2.find(tok.str()) != functionNames2.end())
-            var.push_back(tok.tokAt(4));
-    }
-}
-
-
 /// @addtogroup Checks
 /// @{
 
-
-/**
- * @brief %Check for null pointer usage (using ExecutionPath)
- */
-
-class CheckNullpointer : public ExecutionPath
-{
-public:
-    /** Startup constructor */
-    CheckNullpointer(Check *c) : ExecutionPath(c, 0), null(false)
-    {
-    }
-
-private:
-    /** Create checking of specific variable: */
-    CheckNullpointer(Check *c, const unsigned int id, const std::string &name)
-        : ExecutionPath(c, id),
-          varname(name),
-          null(false)
-    {
-    }
-
-    /** Copy this check */
-    ExecutionPath *copy()
-    {
-        return new CheckNullpointer(*this);
-    }
-
-    /** no implementation => compiler error if used by accident */
-    void operator=(const CheckNullpointer &);
-
-    /** is other execution path equal? */
-    bool is_equal(const ExecutionPath *e) const
-    {
-        const CheckNullpointer *c = static_cast<const CheckNullpointer *>(e);
-        return (varname == c->varname && null == c->null);
-    }
-
-    /** variable name for this check (empty => dummy check) */
-    const std::string varname;
-
-    /** is this variable null? */
-    bool null;
-
-    /** variable is set to null */
-    static void setnull(std::list<ExecutionPath *> &checks, const unsigned int varid)
-    {
-        std::list<ExecutionPath *>::iterator it;
-        for (it = checks.begin(); it != checks.end(); ++it)
-        {
-            CheckNullpointer *c = dynamic_cast<CheckNullpointer *>(*it);
-            if (c && c->varId == varid)
-                c->null = true;
-        }
-    }
-
-    /**
-     * Dereferencing variable. Check if it is safe (if the variable is null there's an error)
-     * @param checks Checks
-     * @param tok token where dereferencing happens
-     */
-    static void dereference(std::list<ExecutionPath *> &checks, const Token *tok)
-    {
-        const unsigned int varid(tok->varId());
-
-        std::list<ExecutionPath *>::iterator it;
-        for (it = checks.begin(); it != checks.end(); ++it)
-        {
-            CheckNullpointer *c = dynamic_cast<CheckNullpointer *>(*it);
-            if (c && c->varId == varid && c->null)
-            {
-                CheckOther *checkOther = dynamic_cast<CheckOther *>(c->owner);
-                if (checkOther)
-                {
-                    checkOther->nullPointerError(tok, c->varname);
-                    return;
-                }
-            }
-        }
-    }
-
-    /** parse tokens */
-    const Token *parse(const Token &tok, std::list<ExecutionPath *> &checks) const
-    {
-        if (Token::Match(tok.previous(), "[;{}] const| %type% * %var% ;"))
-        {
-            const Token * vartok = tok.tokAt(2);
-
-            if (tok.str() == "const")
-                vartok = vartok->next();
-
-            if (vartok->varId() != 0)
-                checks.push_back(new CheckNullpointer(owner, vartok->varId(), vartok->str()));
-            return vartok->next();
-        }
-
-        // Template pointer variable..
-        if (Token::Match(tok.previous(), "[;{}] %type% ::|<"))
-        {
-            const Token * vartok = &tok;
-            while (Token::Match(vartok, "%type% ::"))
-                vartok = vartok->tokAt(2);
-            if (Token::Match(vartok, "%type% < %type%"))
-            {
-                vartok = vartok->tokAt(3);
-                while (vartok && (vartok->str() == "*" || vartok->isName()))
-                    vartok = vartok->next();
-            }
-            if (vartok
-                && (vartok->str() == ">" || vartok->isName())
-                && Token::Match(vartok->next(), "* %var% ;|="))
-            {
-                vartok = vartok->tokAt(2);
-                checks.push_back(new CheckNullpointer(owner, vartok->varId(), vartok->str()));
-                if (Token::simpleMatch(vartok->next(), "= 0 ;"))
-                    setnull(checks, vartok->varId());
-                return vartok->next();
-            }
-        }
-
-        if (Token::simpleMatch(&tok, "try {"))
-        {
-            // Bail out all used variables
-            unsigned int indentlevel = 0;
-            for (const Token *tok2 = &tok; tok2; tok2 = tok2->next())
-            {
-                if (tok2->str() == "{")
-                    ++indentlevel;
-                else if (tok2->str() == "}")
-                {
-                    if (indentlevel == 0)
-                        break;
-                    if (indentlevel == 1 && !Token::simpleMatch(tok2,"} catch ("))
-                        return tok2;
-                    --indentlevel;
-                }
-                else if (tok2->varId())
-                    bailOutVar(checks,tok2->varId());
-            }
-        }
-
-        if (Token::Match(&tok, "%var% ("))
-        {
-            if (tok.str() == "sizeof")
-                return tok.next()->link();
-
-            // parse usage..
-            std::list<const Token *> var;
-            parseFunctionCall(tok, var, 0);
-            for (std::list<const Token *>::const_iterator it = var.begin(); it != var.end(); ++it)
-                dereference(checks, *it);
-        }
-
-        if (tok.varId() != 0)
-        {
-            if (Token::Match(tok.previous(), "[;{}=] %var% = 0 ;"))
-                setnull(checks, tok.varId());
-            else if (Token::Match(tok.tokAt(-2), "[;{}=+-/(,] * %var%"))
-                dereference(checks, &tok);
-            else if (Token::Match(tok.tokAt(-2), "return * %var%"))
-                dereference(checks, &tok);
-            else if (!Token::simpleMatch(tok.tokAt(-2), "& (") && Token::Match(tok.next(), ". %var%"))
-                dereference(checks, &tok);
-            else if (Token::Match(tok.previous(), "[;{}=+-/(,] %var% [ %any% ]"))
-                dereference(checks, &tok);
-            else if (Token::Match(tok.previous(), "return %var% [ %any% ]"))
-                dereference(checks, &tok);
-            else if (Token::Match(&tok, "%var% ("))
-                dereference(checks, &tok);
-            else
-                bailOutVar(checks, tok.varId());
-        }
-
-        else if (tok.str() == "delete")
-        {
-            const Token *ret = tok.next();
-            if (Token::simpleMatch(ret, "[ ]"))
-                ret = ret->tokAt(2);
-            if (Token::Match(ret, "%var% ;"))
-                return ret->next();
-        }
-
-        return &tok;
-    }
-
-    /** parse condition. @sa ExecutionPath::parseCondition */
-    bool parseCondition(const Token &tok, std::list<ExecutionPath *> &checks)
-    {
-        for (const Token *tok2 = &tok; tok2; tok2 = tok2->next())
-        {
-            if (tok2->str() == "(" || tok2->str() == ")")
-                break;
-            if (Token::Match(tok2, "[<>=] * %var%"))
-                dereference(checks, tok2->tokAt(2));
-        }
-
-        if (Token::Match(&tok, "!| %var% ("))
-        {
-            std::list<const Token *> var;
-            parseFunctionCall(tok.str() == "!" ? *tok.next() : tok, var, 0);
-            for (std::list<const Token *>::const_iterator it = var.begin(); it != var.end(); ++it)
-                dereference(checks, *it);
-        }
-
-        return ExecutionPath::parseCondition(tok, checks);
-    }
-
-
-    void parseLoopBody(const Token *tok, std::list<ExecutionPath *> &checks) const
-    {
-        while (tok)
-        {
-            if (Token::Match(tok, "{|}|return|goto|break|if"))
-                return;
-            const Token *next = parse(*tok, checks);
-            if (next)
-                tok = tok->next();
-        }
-    }
-
-};
-
-
 /**
  * @brief %Check that uninitialized variables aren't used (using ExecutionPath)
  * */
@@ -3483,13 +2774,13 @@ private:
             // parse usage..
             {
                 std::list<const Token *> var;
-                parseFunctionCall(tok, var, 1);
+                CheckNullPointer::parseFunctionCall(tok, var, 1);
                 for (std::list<const Token *>::const_iterator it = var.begin(); it != var.end(); ++it)
                     use_array(checks, *it);
 
                 // Using uninitialized pointer is bad if using null pointer is bad
                 std::list<const Token *> var2;
-                parseFunctionCall(tok, var2, 0);
+                CheckNullPointer::parseFunctionCall(tok, var2, 0);
                 for (std::list<const Token *>::const_iterator it = var2.begin(); it != var2.end(); ++it)
                 {
                     if (std::find(var.begin(), var.end(), *it) == var.end())
@@ -3771,7 +3062,7 @@ private:
         else if (Token::Match(&tok, "!| %var% ("))
         {
             std::list<const Token *> var;
-            parseFunctionCall(tok.str() == "!" ? *tok.next() : tok, var, 1);
+            CheckNullPointer::parseFunctionCall(tok.str() == "!" ? *tok.next() : tok, var, 1);
             for (std::list<const Token *>::const_iterator it = var.begin(); it != var.end(); ++it)
                 use_array(checks, *it);
         }
@@ -3909,12 +3200,6 @@ void CheckOther::saveAnalysisData(const std::set<std::string> &data) const
 
 void CheckOther::executionPaths()
 {
-    // Check for null pointer errors..
-    {
-        CheckNullpointer c(this);
-        checkExecutionPaths(_tokenizer->tokens(), &c);
-    }
-
     // check if variable is accessed uninitialized..
     {
         // no writing if multiple threads are used (TODO: thread safe analysis?)
@@ -4160,21 +3445,6 @@ void CheckOther::strPlusChar(const Token *tok)
     reportError(tok, Severity::error, "strPlusChar", "Unusual pointer arithmetic");
 }
 
-void CheckOther::nullPointerError(const Token *tok)
-{
-    reportError(tok, Severity::error, "nullPointer", "Null pointer dereference");
-}
-
-void CheckOther::nullPointerError(const Token *tok, const std::string &varname)
-{
-    reportError(tok, Severity::error, "nullPointer", "Possible null pointer dereference: " + varname);
-}
-
-void CheckOther::nullPointerError(const Token *tok, const std::string &varname, const unsigned int line)
-{
-    reportError(tok, Severity::error, "nullPointer", "Possible null pointer dereference: " + varname + " - otherwise it is redundant to check if " + varname + " is null at line " + MathLib::toString<unsigned int>(line));
-}
-
 void CheckOther::uninitstringError(const Token *tok, const std::string &varname)
 {
     reportError(tok, Severity::error, "uninitstring", "Dangerous usage of '" + varname + "' (strncpy doesn't always 0-terminate it)");

lib/checkother.h

@@ -50,8 +50,6 @@ public:
     {
         CheckOther checkOther(tokenizer, settings, errorLogger);
 
-        checkOther.nullPointer();
-
         // Coding style checks
         checkOther.warningOldStylePointerCast();
         checkOther.checkUnsignedDivision();
@@ -82,7 +80,6 @@ public:
         checkOther.checkFflushOnInputStream();
         checkOther.invalidScanf();
 
-        checkOther.nullConstantDereference();
         checkOther.checkSelfAssignment();
         checkOther.checkIncorrectLogicOperator();
 
@@ -141,18 +138,6 @@ public:
     /** @brief str plus char (unusual pointer arithmetic) */
     void strPlusChar();
 
-    /** @brief possible null pointer dereference */
-    void nullPointer();
-
-    /**
-     * @brief Does one part of the check for nullPointer().
-     * Checking if pointer is NULL and then dereferencing it..
-     */
-    void nullPointerByCheckAndDeRef();
-
-    /** @brief dereferencing null constant (after Tokenizer::simplifyKnownVariables) */
-    void nullConstantDereference();
-
     /** @brief new type of check: check execution paths */
     void executionPaths();
 
@@ -210,9 +195,6 @@ public:
     void variableScopeError(const Token *tok, const std::string &varname);
     void conditionAlwaysTrueFalse(const Token *tok, const std::string &truefalse);
     void strPlusChar(const Token *tok);
-    void nullPointerError(const Token *tok);  // variable name unknown / doesn't exist
-    void nullPointerError(const Token *tok, const std::string &varname);
-    void nullPointerError(const Token *tok, const std::string &varname, const unsigned int line);
     void uninitstringError(const Token *tok, const std::string &varname);
     void uninitdataError(const Token *tok, const std::string &varname);
     void uninitvarError(const Token *tok, const std::string &varname);
@@ -231,7 +213,6 @@ public:
         // error
         sprintfOverlappingDataError(0, "varname");
         udivError(0);
-        nullPointerError(0, "pointer");
         uninitstringError(0, "varname");
         uninitdataError(0, "varname");
         uninitvarError(0, "varname");
@@ -278,7 +259,6 @@ public:
                // error
                "* [[OverlappingData|bad usage of the function 'sprintf' (overlapping data)]]\n"
                "* division with zero\n"
-               "* null pointer dereferencing\n"
                "* using uninitialized variables and data\n"
                "* using fflush() on an input stream\n"
                "* scoped object destroyed immediately after construction\n"
@@ -310,38 +290,6 @@ public:
 
 private:
 
-    /**
-     * @brief Does one part of the check for nullPointer().
-     * Locate insufficient null-pointer handling after loop
-     */
-    void nullPointerAfterLoop();
-
-    /**
-     * @brief Does one part of the check for nullPointer().
-     * looping through items in a linked list in a inner loop..
-     */
-    void nullPointerLinkedList();
-
-    /**
-     * @brief Does one part of the check for nullPointer().
-     * Dereferencing a struct pointer and then checking if it's NULL..
-     */
-    void nullPointerStructByDeRefAndChec();
-
-    /**
-     * @brief Does one part of the check for nullPointer().
-     * Dereferencing a pointer and then checking if it's NULL..
-     */
-    void nullPointerByDeRefAndChec();
-
-    /**
-     * @brief Does one part of the check for nullPointer().
-     * -# initialize pointer to 0
-     * -# conditionally assign pointer
-     * -# dereference pointer
-     */
-    void nullPointerConditionalAssignment();
-
     /**
      * @brief Used in warningRedundantCode()
      * Iterates through the %var% tokens in a fully qualified name and concatenates them.

lib/lib.pri

@@ -6,6 +6,7 @@ HEADERS += $$PWD/check.h \
            $$PWD/checkclass.h \
            $$PWD/checkexceptionsafety.h \
            $$PWD/checkmemoryleak.h \
+           $$PWD/checknullpointer.h \
            $$PWD/checkobsoletefunctions.h \
            $$PWD/checkother.h \
            $$PWD/checkpostfixoperator.h \
@@ -30,6 +31,7 @@ SOURCES += $$PWD/checkautovariables.cpp \
            $$PWD/checkclass.cpp \
            $$PWD/checkexceptionsafety.cpp \
            $$PWD/checkmemoryleak.cpp \
+           $$PWD/checknullpointer.cpp \
            $$PWD/checkobsoletefunctions.cpp \
            $$PWD/checkother.cpp \
            $$PWD/checkpostfixoperator.cpp \

test/testnullpointer.cpp

@@ -0,0 +1,677 @@
+/*
+ * Cppcheck - A tool for static C/C++ code analysis
+ * Copyright (C) 2007-2010 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 "checknullpointer.h"
+#include "testsuite.h"
+#include <sstream>
+
+extern std::ostringstream errout;
+
+class TestNullPointer : public TestFixture
+{
+public:
+    TestNullPointer() : TestFixture("TestNullPointer")
+    { }
+
+private:
+
+
+    void run()
+    {
+        TEST_CASE(nullpointer1);
+        TEST_CASE(nullpointer2);
+        TEST_CASE(nullpointer3);    // dereferencing struct and then checking if it's null
+        TEST_CASE(nullpointer4);
+        TEST_CASE(nullpointer5);    // References should not be checked
+        TEST_CASE(nullpointer6);
+        TEST_CASE(nullpointer7);
+        TEST_CASE(nullpointer8);
+        TEST_CASE(nullpointer9);
+        TEST_CASE(nullpointer10);	// check if pointer is null and then dereference it
+    }
+
+    void check(const char code[])
+    {
+        // Tokenize..
+        Tokenizer tokenizer;
+        std::istringstream istr(code);
+        tokenizer.tokenize(istr, "test.cpp");
+
+        // Clear the error buffer..
+        errout.str("");
+
+        // Check for redundant code..
+        Settings settings;
+        settings._checkCodingStyle = true;
+        CheckNullPointer checkNullPointer(&tokenizer, &settings, this);
+        checkNullPointer.nullPointer();
+        tokenizer.simplifyTokenList();
+        checkNullPointer.nullConstantDereference();
+        checkNullPointer.executionPaths();
+    }
+
+
+    void nullpointer1()
+    {
+        check("int foo(const Token *tok)\n"
+              "{\n"
+              "    while (tok);\n"
+              "    tok = tok->next();\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:4]: (error) Possible null pointer dereference: tok\n", errout.str());
+
+        check("void foo()\n"
+              "{\n"
+              "    for (const Token *tok = tokens; tok; tok = tok->next())\n"
+              "    {\n"
+              "        while (tok && tok->str() != \";\")\n"
+              "            tok = tok->next();\n"
+              "    }\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:3]: (error) Possible null pointer dereference: tok - otherwise it is redundant to check if tok is null at line 5\n", errout.str());
+
+        check("void foo(Token &tok)\n"
+              "{\n"
+              "    for (int i = 0; i < tok.size(); i++ )\n"
+              "    {\n"
+              "        while (!tok)\n"
+              "            char c = tok.read();\n"
+              "    }\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("void foo()\n"
+              "{\n"
+              "    for (const Token *tok = tokens; tok; tok = tok->next())\n"
+              "    {\n"
+              "        while (tok && tok->str() != \";\")\n"
+              "            tok = tok->next();\n"
+              "        if( !tok ) break;\n"
+              "    }\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("void foo()\n"
+              "{\n"
+              "    for (const Token *tok = tokens; tok; tok = tok ? tok->next() : NULL)\n"
+              "    {\n"
+              "        while (tok && tok->str() != \";\")\n"
+              "            tok = tok->next();\n"
+              "    }\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("void foo(A*a)\n"
+              "{\n"
+              "  switch (a->b()) {\n"
+              "    case 1:\n"
+              "      while( a ){\n"
+              "        a = a->next;\n"
+              "      }\n"
+              "    break;\n"
+              "    case 2:\n"
+              "      a->b();\n"
+              "      break;\n"
+              "  }\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        // ticket #1923 - no false positive when using else if
+        check("void f(A *a)\n"
+              "{\n"
+              "    if (a->x == 1)\n"
+              "    {\n"
+              "        a = a->next;\n"
+              "    }\n"
+              "    else if (a->x == 2) { }\n"
+              "    if (a) { }\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        // ticket #2134 - sizeof doesn't dereference
+        check("void f() {\n"
+              "    int c = 1;\n"
+              "    int *list = NULL;\n"
+              "    sizeof(*list);\n"
+              "    if (!list)\n"
+              "        ;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+    }
+
+    void nullpointer2()
+    {
+        // Null pointer dereference can only happen with pointers
+        check("void foo()\n"
+              "{\n"
+              "    Fred fred;\n"
+              "    while (fred);\n"
+              "    fred.hello();\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+    }
+
+    // Dereferencing a struct and then checking if it is null
+    // This is checked by this function:
+    //        CheckOther::nullPointerStructByDeRefAndChec
+    void nullpointer3()
+    {
+        // errors..
+        check("void foo(struct ABC *abc)\n"
+              "{\n"
+              "    int a = abc->a;\n"
+              "    if (!abc)\n"
+              "        ;\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:3]: (error) Possible null pointer dereference: abc - otherwise it is redundant to check if abc is null at line 4\n", errout.str());
+
+        check("void foo(struct ABC *abc)\n"
+              "{\n"
+              "    bar(abc->a);\n"
+              "    if (!abc)\n"
+              "        ;\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:3]: (error) Possible null pointer dereference: abc - otherwise it is redundant to check if abc is null at line 4\n", errout.str());
+
+        // ok dereferencing in a condition
+        check("void foo(struct ABC *abc)\n"
+              "{\n"
+              "    if (abc && abc->a);\n"
+              "    if (!abc)\n"
+              "        ;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        // ok to use a linked list..
+        check("void foo(struct ABC *abc)\n"
+              "{\n"
+              "    abc = abc->next;\n"
+              "    if (!abc)\n"
+              "        ;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        // reassign struct..
+        check("void foo(struct ABC *abc)\n"
+              "{\n"
+              "    int a = abc->a;\n"
+              "    abc = abc->next;\n"
+              "    if (!abc)\n"
+              "        ;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("void foo(struct ABC *abc)\n"
+              "{\n"
+              "    int a = abc->a;\n"
+              "    f(&abc);\n"
+              "    if (!abc)\n"
+              "        ;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        // goto..
+        check("void foo(struct ABC *abc)\n"
+              "{\n"
+              "    int a;\n"
+              "    if (!abc)\n"
+              "        goto out;"
+              "    a = abc->a;\n"
+              "    return;\n"
+              "out:\n"
+              "    if (!abc)\n"
+              "        ;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        // loops..
+        check("void freeAbc(struct ABC *abc)\n"
+              "{\n"
+              "    while (abc)\n"
+              "    {\n"
+              "        struct ABC *next = abc->next;\n"
+              "        if (abc) delete abc;\n"
+              "        abc = next;\n"
+              "    }\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("void foo(struct ABC *abc)\n"
+              "{\n"
+              "    int a = abc->a;"
+              "    do\n"
+              "    {\n"
+              "        if (abc)\n"
+              "            abc = abc->next;\n"
+              "        --a;\n"
+              "    }\n"
+              "    while (a > 0);\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("void f()\n"
+              "{\n"
+              "    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())\n"
+              "    {\n"
+              "        while (tok && tok->str() != \"{\")\n"
+              "            tok = tok->next();\n"
+              "        if (!tok)\n"
+              "            return;\n"
+              "    }\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        // dynamic_cast..
+        check("void foo(ABC *abc)\n"
+              "{\n"
+              "    int a = abc->a;\n"
+              "    if (!dynamic_cast<DEF *>(abc))\n"
+              "        ;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+    }
+
+    // Dereferencing a pointer and then checking if it is null
+    void nullpointer4()
+    {
+        // errors..
+        check("void foo(int *p)\n"
+              "{\n"
+              "    *p = 0;\n"
+              "    if (!p)\n"
+              "        ;\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:3]: (error) Possible null pointer dereference: p - otherwise it is redundant to check if p is null at line 4\n", errout.str());
+
+        check("void foo(int *p)\n"
+              "{\n"
+              "    bar(*p);\n"
+              "    if (!p)\n"
+              "        ;\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:3]: (error) Possible null pointer dereference: p - otherwise it is redundant to check if p is null at line 4\n", errout.str());
+
+        // no error
+        check("void foo()\n"
+              "{\n"
+              "    int *p;\n"
+              "    f(&p);\n"
+              "    if (!p)\n"
+              "        ;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("void foo()\n"
+              "{\n"
+              "    int **p = f();\n"
+              "    if (!p)\n"
+              "        ;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("void foo(int *p)\n"
+              "{\n"
+              "    if (x)\n"
+              "        p = 0;\n"
+              "    else\n"
+              "        *p = 0;\n"
+              "    if (!p)\n"
+              "        ;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("void foo(int x)\n"
+              "{\n"
+              "    int a = 2 * x;"
+              "    if (x == 0)\n"
+              "        ;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("void foo(int *p)\n"
+              "{\n"
+              "    int var1 = p ? *p : 0;\n"
+              "    if (!p)\n"
+              "        ;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("void foo(P *p)\n"
+              "{\n"
+              "  while (p)\n"
+              "    if (p->check())\n"
+              "      break;\n"
+              "    else\n"
+              "      p = p->next();\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+    }
+
+    void nullpointer5()
+    {
+        // errors..
+        check("void foo(A &a)\n"
+              "{\n"
+              " char c = a.c();\n"
+              " if (!a)\n"
+              "   return;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+    }
+
+    // Execution paths..
+    void nullpointer6()
+    {
+        // errors..
+        check("static void foo()\n"
+              "{\n"
+              "    Foo *p = 0;\n"
+              "    if (a == 1)\n"
+              "        p = new FooBar;\n"
+              "    else if (a == 2)\n"
+              "        p = new FooCar;\n"
+              "    p->abcd();\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:8]: (error) Possible null pointer dereference: p\n", errout.str());
+
+        check("static void foo()\n"
+              "{\n"
+              "    int *p = 0;\n"
+              "    int *q = p;\n"
+              "    q[0] = 0;\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:5]: (error) Possible null pointer dereference: q\n", errout.str());
+
+        check("static void foo()\n"
+              "{\n"
+              "    int *p = 0;\n"
+              "    int &r = *p;\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:4]: (error) Null pointer dereference\n", errout.str());
+
+        check("static void foo(int x)\n"
+              "{\n"
+              "    int *p = 0;\n"
+              "    int y = 5 + *p;\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:4]: (error) Null pointer dereference\n", errout.str());
+
+        check("static void foo(int x)\n"
+              "{\n"
+              "    Foo<int> *abc = 0;\n"
+              "    abc->a();\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:4]: (error) Possible null pointer dereference: abc\n", errout.str());
+
+        check("static void foo()\n"
+              "{\n"
+              "    int *p(0);\n"
+              "    std::cout << *p;"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:4]: (error) Null pointer dereference\n", errout.str());
+
+        check("void f()\n"
+              "{\n"
+              "    char *c = 0;\n"
+              "    {\n"
+              "        delete c;\n"
+              "    }\n"
+              "    c[0] = 0;\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:7]: (error) Possible null pointer dereference: c\n", errout.str());
+
+        check("static void foo()\n"
+              "{\n"
+              "    int *p = 0;\n"
+              "    if (3 > *p);\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:4]: (error) Null pointer dereference\n", errout.str());
+
+        check("void f()\n"
+              "{\n"
+              "    if (x) {\n"
+              "        char *c = 0;\n"
+              "        *c = 0;\n"
+              "    }\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:5]: (error) Null pointer dereference\n", errout.str());
+
+        // no false positive..
+        check("static void foo()\n"
+              "{\n"
+              "    Foo *p = 0;\n"
+              "    p = new Foo;\n"
+              "    p->abcd();\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("static void foo()\n"
+              "{\n"
+              "    Foo *p = 0;\n"
+              "    if (!p)\n"
+              "        return;\n"
+              "    p->abcd();\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("static void foo()\n"
+              "{\n"
+              "    int *p = 0;\n"
+              "    exit();\n"
+              "    *p = 0;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("static void foo(int a)\n"
+              "{\n"
+              "    Foo *p = 0;\n"
+              "    if (a && p)\n"
+              "        p->do_something();\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("void foo()\n"
+              "{\n"
+              "    int sz = sizeof((*(struct dummy *)0).x);\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("void get_offset(long &offset)\n"
+              "{\n"
+              "    mystruct * temp; temp = 0;\n"
+              "    offset = (long)(&(temp->z));\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        // Ticket #1893 - try/catch inside else
+        check("int *test(int *Z)\n"
+              "{\n"
+              "    int *Q=NULL;\n"
+              "    if (Z) {\n"
+              "        Q = Z;\n"
+              "    }\n"
+              "    else {\n"
+              "        Z = new int;\n"
+              "        try {\n"
+              "        } catch(...) {\n"
+              "        }\n"
+              "        Q = Z;\n"
+              "    }\n"
+              "    *Q=1;\n"
+              "    return Q;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("int *test(int *Z)\n"
+              "{\n"
+              "    int *Q=NULL;\n"
+              "    if (Z) {\n"
+              "        Q = Z;\n"
+              "    }\n"
+              "    else {\n"
+              "        try {\n"
+              "        } catch(...) {\n"
+              "        }\n"
+              "    }\n"
+              "    *Q=1;\n"
+              "    return Q;\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:12]: (error) Possible null pointer dereference: Q\n", errout.str());
+
+        // Ticket #2052 (false positive for 'else continue;')
+        check("void f() {\n"
+              "    for (int x = 0; x < 5; ++x) {"
+              "        int *p = 0;\n"
+              "        if (a(x)) p=b(x);\n"
+              "        else continue;\n"
+              "        *p = 0;\n"
+              "    }\n"
+              "}");
+        ASSERT_EQUALS("", errout.str());
+
+        // function pointer..
+        check("void foo()\n"
+              "{\n"
+              "    void (*f)();\n"
+              "    f = 0;\n"
+              "    f();\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:5]: (error) Possible null pointer dereference: f\n", errout.str());
+
+        check("static void foo()\n"
+              "{\n"
+              "    int *p = 0;\n"
+              "    int *p2 = 0;\n"
+              "    int r = *p;\n"
+              "    int r2 = *p2;\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:5]: (error) Null pointer dereference\n"
+                      "[test.cpp:6]: (error) Null pointer dereference\n", errout.str());
+
+        // loops..
+        check("void f() {\n"
+              "    int *p = 0;\n"
+              "    for (int i = 0; i < 10; ++i) {\n"
+              "        int x = *p + 1;\n"
+              "    }\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:4]: (error) Possible null pointer dereference: p\n", errout.str());
+
+        check("void f(int a) {\n"
+              "    const char *p = 0;\n"
+              "    if (a) {\n"
+              "    	 p = \"abcd\";\n"
+              "    }\n"
+              "    for (int i = 0; i < 3; i++) {\n"
+              "        if (a && (p[i] == '1'));\n"
+              "    }\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+    }
+
+    void nullpointer7()
+    {
+        check("void foo()\n"
+              "{\n"
+              "  wxLongLong x = 0;\n"
+              "  int y = x.GetValue();\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+    }
+
+    void nullpointer8()
+    {
+        check("void foo()\n"
+              "{\n"
+              "  const char * x = 0;\n"
+              "  strdup(x);\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:4]: (error) Possible null pointer dereference: x\n", errout.str());
+        check("void foo()\n"
+              "{\n"
+              "  char const * x = 0;\n"
+              "  strdup(x);\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:4]: (error) Possible null pointer dereference: x\n", errout.str());
+    }
+
+    void nullpointer9() //#ticket 1778
+    {
+        check("void foo()\n"
+              "{\n"
+              "  std::string * x = 0;\n"
+              "  *x = \"test\";\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:4]: (error) Possible null pointer dereference: x\n", errout.str());
+    }
+
+    // Check if pointer is null and the dereference it
+    void nullpointer10()
+    {
+        check("void foo(char *p) {\n"
+              "    if (!p) {\n"
+              "    }\n"
+              "    *p = 0;\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:4]: (error) Possible null pointer dereference: p\n", errout.str());
+
+        check("void foo(abc *p) {\n"
+              "    if (!p) {\n"
+              "    }\n"
+              "    else if (!p->x) {\n"
+              "    }\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("void foo(char *p) {\n"
+              "    if (!p) {\n"
+              "        abort();\n"
+              "    }\n"
+              "    *p = 0;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("void foo(char *p) {\n"
+              "    if (!p) {\n"
+              "        throw x;\n"
+              "    }\n"
+              "    *p = 0;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("void foo() {\n"
+              "    if (!p) {\n"
+              "        switch (x) { }\n"
+              "    }\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        // This is why this check can't be used on the simplified token list
+        check("void f(Foo *foo) {\n"
+              "    if (!dynamic_cast<bar *>(foo)) {\n"
+              "        *foo = 0;\n"
+              "    }\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+    }
+};
+
+REGISTER_TEST(TestNullPointer)
+

test/testother.cpp

@@ -59,17 +59,6 @@ private:
         TEST_CASE(varScope9);		// classes may have extra side-effects
         TEST_CASE(varScope10);      // Undefined macro FOR
 
-        TEST_CASE(nullpointer1);
-        TEST_CASE(nullpointer2);
-        TEST_CASE(nullpointer3);    // dereferencing struct and then checking if it's null
-        TEST_CASE(nullpointer4);
-        TEST_CASE(nullpointer5);    // References should not be checked
-        TEST_CASE(nullpointer6);
-        TEST_CASE(nullpointer7);
-        TEST_CASE(nullpointer8);
-        TEST_CASE(nullpointer9);
-        TEST_CASE(nullpointer10);	// check if pointer is null and then dereference it
-
         TEST_CASE(uninitvar1);
         TEST_CASE(uninitvar_alloc);     // data is allocated but not initialized
         TEST_CASE(uninitvar_arrays);    // arrays
@@ -594,633 +583,6 @@ private:
     }
 
 
-    void checkNullPointer(const char code[])
-    {
-        // Tokenize..
-        Tokenizer tokenizer;
-        std::istringstream istr(code);
-        tokenizer.tokenize(istr, "test.cpp");
-
-        // Clear the error buffer..
-        errout.str("");
-
-        // Check for redundant code..
-        Settings settings;
-        settings._checkCodingStyle = true;
-        CheckOther checkOther(&tokenizer, &settings, this);
-        checkOther.nullPointer();
-
-        tokenizer.simplifyTokenList();
-        checkOther.nullConstantDereference();
-        checkOther.executionPaths();
-    }
-
-
-    void nullpointer1()
-    {
-        checkNullPointer("int foo(const Token *tok)\n"
-                         "{\n"
-                         "    while (tok);\n"
-                         "    tok = tok->next();\n"
-                         "}\n");
-        ASSERT_EQUALS("[test.cpp:4]: (error) Possible null pointer dereference: tok\n", errout.str());
-
-        checkNullPointer("void foo()\n"
-                         "{\n"
-                         "    for (const Token *tok = tokens; tok; tok = tok->next())\n"
-                         "    {\n"
-                         "        while (tok && tok->str() != \";\")\n"
-                         "            tok = tok->next();\n"
-                         "    }\n"
-                         "}\n");
-        ASSERT_EQUALS("[test.cpp:3]: (error) Possible null pointer dereference: tok - otherwise it is redundant to check if tok is null at line 5\n", errout.str());
-
-        checkNullPointer("void foo(Token &tok)\n"
-                         "{\n"
-                         "    for (int i = 0; i < tok.size(); i++ )\n"
-                         "    {\n"
-                         "        while (!tok)\n"
-                         "            char c = tok.read();\n"
-                         "    }\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        checkNullPointer("void foo()\n"
-                         "{\n"
-                         "    for (const Token *tok = tokens; tok; tok = tok->next())\n"
-                         "    {\n"
-                         "        while (tok && tok->str() != \";\")\n"
-                         "            tok = tok->next();\n"
-                         "        if( !tok ) break;\n"
-                         "    }\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        checkNullPointer("void foo()\n"
-                         "{\n"
-                         "    for (const Token *tok = tokens; tok; tok = tok ? tok->next() : NULL)\n"
-                         "    {\n"
-                         "        while (tok && tok->str() != \";\")\n"
-                         "            tok = tok->next();\n"
-                         "    }\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        checkNullPointer("void foo(A*a)\n"
-                         "{\n"
-                         "  switch (a->b()) {\n"
-                         "    case 1:\n"
-                         "      while( a ){\n"
-                         "        a = a->next;\n"
-                         "      }\n"
-                         "    break;\n"
-                         "    case 2:\n"
-                         "      a->b();\n"
-                         "      break;\n"
-                         "  }\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        // ticket #1923 - no false positive when using else if
-        checkNullPointer("void f(A *a)\n"
-                         "{\n"
-                         "    if (a->x == 1)\n"
-                         "    {\n"
-                         "        a = a->next;\n"
-                         "    }\n"
-                         "    else if (a->x == 2) { }\n"
-                         "    if (a) { }\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        // ticket #2134 - sizeof doesn't dereference
-        checkNullPointer("void f() {\n"
-                         "    int c = 1;\n"
-                         "    int *list = NULL;\n"
-                         "    sizeof(*list);\n"
-                         "    if (!list)\n"
-                         "        ;\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-    }
-
-    void nullpointer2()
-    {
-        // Null pointer dereference can only happen with pointers
-        checkNullPointer("void foo()\n"
-                         "{\n"
-                         "    Fred fred;\n"
-                         "    while (fred);\n"
-                         "    fred.hello();\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-    }
-
-    // Dereferencing a struct and then checking if it is null
-    // This is checked by this function:
-    //        CheckOther::nullPointerStructByDeRefAndChec
-    void nullpointer3()
-    {
-        // errors..
-        checkNullPointer("void foo(struct ABC *abc)\n"
-                         "{\n"
-                         "    int a = abc->a;\n"
-                         "    if (!abc)\n"
-                         "        ;\n"
-                         "}\n");
-        ASSERT_EQUALS("[test.cpp:3]: (error) Possible null pointer dereference: abc - otherwise it is redundant to check if abc is null at line 4\n", errout.str());
-
-        checkNullPointer("void foo(struct ABC *abc)\n"
-                         "{\n"
-                         "    bar(abc->a);\n"
-                         "    if (!abc)\n"
-                         "        ;\n"
-                         "}\n");
-        ASSERT_EQUALS("[test.cpp:3]: (error) Possible null pointer dereference: abc - otherwise it is redundant to check if abc is null at line 4\n", errout.str());
-
-        // ok dereferencing in a condition
-        checkNullPointer("void foo(struct ABC *abc)\n"
-                         "{\n"
-                         "    if (abc && abc->a);\n"
-                         "    if (!abc)\n"
-                         "        ;\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        // ok to use a linked list..
-        checkNullPointer("void foo(struct ABC *abc)\n"
-                         "{\n"
-                         "    abc = abc->next;\n"
-                         "    if (!abc)\n"
-                         "        ;\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        // reassign struct..
-        checkNullPointer("void foo(struct ABC *abc)\n"
-                         "{\n"
-                         "    int a = abc->a;\n"
-                         "    abc = abc->next;\n"
-                         "    if (!abc)\n"
-                         "        ;\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        checkNullPointer("void foo(struct ABC *abc)\n"
-                         "{\n"
-                         "    int a = abc->a;\n"
-                         "    f(&abc);\n"
-                         "    if (!abc)\n"
-                         "        ;\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        // goto..
-        checkNullPointer("void foo(struct ABC *abc)\n"
-                         "{\n"
-                         "    int a;\n"
-                         "    if (!abc)\n"
-                         "        goto out;"
-                         "    a = abc->a;\n"
-                         "    return;\n"
-                         "out:\n"
-                         "    if (!abc)\n"
-                         "        ;\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        // loops..
-        checkNullPointer("void freeAbc(struct ABC *abc)\n"
-                         "{\n"
-                         "    while (abc)\n"
-                         "    {\n"
-                         "        struct ABC *next = abc->next;\n"
-                         "        if (abc) delete abc;\n"
-                         "        abc = next;\n"
-                         "    }\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        checkNullPointer("void foo(struct ABC *abc)\n"
-                         "{\n"
-                         "    int a = abc->a;"
-                         "    do\n"
-                         "    {\n"
-                         "        if (abc)\n"
-                         "            abc = abc->next;\n"
-                         "        --a;\n"
-                         "    }\n"
-                         "    while (a > 0);\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        checkNullPointer("void f()\n"
-                         "{\n"
-                         "    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())\n"
-                         "    {\n"
-                         "        while (tok && tok->str() != \"{\")\n"
-                         "            tok = tok->next();\n"
-                         "        if (!tok)\n"
-                         "            return;\n"
-                         "    }\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        // dynamic_cast..
-        checkNullPointer("void foo(ABC *abc)\n"
-                         "{\n"
-                         "    int a = abc->a;\n"
-                         "    if (!dynamic_cast<DEF *>(abc))\n"
-                         "        ;\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-    }
-
-    // Dereferencing a pointer and then checking if it is null
-    void nullpointer4()
-    {
-        // errors..
-        checkNullPointer("void foo(int *p)\n"
-                         "{\n"
-                         "    *p = 0;\n"
-                         "    if (!p)\n"
-                         "        ;\n"
-                         "}\n");
-        ASSERT_EQUALS("[test.cpp:3]: (error) Possible null pointer dereference: p - otherwise it is redundant to check if p is null at line 4\n", errout.str());
-
-        checkNullPointer("void foo(int *p)\n"
-                         "{\n"
-                         "    bar(*p);\n"
-                         "    if (!p)\n"
-                         "        ;\n"
-                         "}\n");
-        ASSERT_EQUALS("[test.cpp:3]: (error) Possible null pointer dereference: p - otherwise it is redundant to check if p is null at line 4\n", errout.str());
-
-        // no error
-        checkNullPointer("void foo()\n"
-                         "{\n"
-                         "    int *p;\n"
-                         "    f(&p);\n"
-                         "    if (!p)\n"
-                         "        ;\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        checkNullPointer("void foo()\n"
-                         "{\n"
-                         "    int **p = f();\n"
-                         "    if (!p)\n"
-                         "        ;\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        checkNullPointer("void foo(int *p)\n"
-                         "{\n"
-                         "    if (x)\n"
-                         "        p = 0;\n"
-                         "    else\n"
-                         "        *p = 0;\n"
-                         "    if (!p)\n"
-                         "        ;\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        checkNullPointer("void foo(int x)\n"
-                         "{\n"
-                         "    int a = 2 * x;"
-                         "    if (x == 0)\n"
-                         "        ;\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        checkNullPointer("void foo(int *p)\n"
-                         "{\n"
-                         "    int var1 = p ? *p : 0;\n"
-                         "    if (!p)\n"
-                         "        ;\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        checkNullPointer("void foo(P *p)\n"
-                         "{\n"
-                         "  while (p)\n"
-                         "    if (p->check())\n"
-                         "      break;\n"
-                         "    else\n"
-                         "      p = p->next();\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-    }
-
-    void nullpointer5()
-    {
-        // errors..
-        checkNullPointer("void foo(A &a)\n"
-                         "{\n"
-                         " char c = a.c();\n"
-                         " if (!a)\n"
-                         "   return;\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-    }
-
-    // Execution paths..
-    void nullpointer6()
-    {
-        // errors..
-        checkNullPointer("static void foo()\n"
-                         "{\n"
-                         "    Foo *p = 0;\n"
-                         "    if (a == 1)\n"
-                         "        p = new FooBar;\n"
-                         "    else if (a == 2)\n"
-                         "        p = new FooCar;\n"
-                         "    p->abcd();\n"
-                         "}\n");
-        ASSERT_EQUALS("[test.cpp:8]: (error) Possible null pointer dereference: p\n", errout.str());
-
-        checkNullPointer("static void foo()\n"
-                         "{\n"
-                         "    int *p = 0;\n"
-                         "    int *q = p;\n"
-                         "    q[0] = 0;\n"
-                         "}\n");
-        ASSERT_EQUALS("[test.cpp:5]: (error) Possible null pointer dereference: q\n", errout.str());
-
-        checkNullPointer("static void foo()\n"
-                         "{\n"
-                         "    int *p = 0;\n"
-                         "    int &r = *p;\n"
-                         "}\n");
-        ASSERT_EQUALS("[test.cpp:4]: (error) Null pointer dereference\n", errout.str());
-
-        checkNullPointer("static void foo(int x)\n"
-                         "{\n"
-                         "    int *p = 0;\n"
-                         "    int y = 5 + *p;\n"
-                         "}\n");
-        ASSERT_EQUALS("[test.cpp:4]: (error) Null pointer dereference\n", errout.str());
-
-        checkNullPointer("static void foo(int x)\n"
-                         "{\n"
-                         "    Foo<int> *abc = 0;\n"
-                         "    abc->a();\n"
-                         "}\n");
-        ASSERT_EQUALS("[test.cpp:4]: (error) Possible null pointer dereference: abc\n", errout.str());
-
-        checkNullPointer("static void foo()\n"
-                         "{\n"
-                         "    int *p(0);\n"
-                         "    std::cout << *p;"
-                         "}\n");
-        ASSERT_EQUALS("[test.cpp:4]: (error) Null pointer dereference\n", errout.str());
-
-        checkNullPointer("void f()\n"
-                         "{\n"
-                         "    char *c = 0;\n"
-                         "    {\n"
-                         "        delete c;\n"
-                         "    }\n"
-                         "    c[0] = 0;\n"
-                         "}\n");
-        ASSERT_EQUALS("[test.cpp:7]: (error) Possible null pointer dereference: c\n", errout.str());
-
-        checkNullPointer("static void foo()\n"
-                         "{\n"
-                         "    int *p = 0;\n"
-                         "    if (3 > *p);\n"
-                         "}\n");
-        ASSERT_EQUALS("[test.cpp:4]: (error) Null pointer dereference\n", errout.str());
-
-        checkNullPointer("void f()\n"
-                         "{\n"
-                         "    if (x) {\n"
-                         "        char *c = 0;\n"
-                         "        *c = 0;\n"
-                         "    }\n"
-                         "}\n");
-        ASSERT_EQUALS("[test.cpp:5]: (error) Null pointer dereference\n", errout.str());
-
-        // no false positive..
-        checkNullPointer("static void foo()\n"
-                         "{\n"
-                         "    Foo *p = 0;\n"
-                         "    p = new Foo;\n"
-                         "    p->abcd();\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        checkNullPointer("static void foo()\n"
-                         "{\n"
-                         "    Foo *p = 0;\n"
-                         "    if (!p)\n"
-                         "        return;\n"
-                         "    p->abcd();\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        checkNullPointer("static void foo()\n"
-                         "{\n"
-                         "    int *p = 0;\n"
-                         "    exit();\n"
-                         "    *p = 0;\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        checkNullPointer("static void foo(int a)\n"
-                         "{\n"
-                         "    Foo *p = 0;\n"
-                         "    if (a && p)\n"
-                         "        p->do_something();\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        checkNullPointer("void foo()\n"
-                         "{\n"
-                         "    int sz = sizeof((*(struct dummy *)0).x);\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        checkNullPointer("void get_offset(long &offset)\n"
-                         "{\n"
-                         "    mystruct * temp; temp = 0;\n"
-                         "    offset = (long)(&(temp->z));\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        // Ticket #1893 - try/catch inside else
-        checkNullPointer("int *test(int *Z)\n"
-                         "{\n"
-                         "    int *Q=NULL;\n"
-                         "    if (Z) {\n"
-                         "        Q = Z;\n"
-                         "    }\n"
-                         "    else {\n"
-                         "        Z = new int;\n"
-                         "        try {\n"
-                         "        } catch(...) {\n"
-                         "        }\n"
-                         "        Q = Z;\n"
-                         "    }\n"
-                         "    *Q=1;\n"
-                         "    return Q;\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        checkNullPointer("int *test(int *Z)\n"
-                         "{\n"
-                         "    int *Q=NULL;\n"
-                         "    if (Z) {\n"
-                         "        Q = Z;\n"
-                         "    }\n"
-                         "    else {\n"
-                         "        try {\n"
-                         "        } catch(...) {\n"
-                         "        }\n"
-                         "    }\n"
-                         "    *Q=1;\n"
-                         "    return Q;\n"
-                         "}\n");
-        ASSERT_EQUALS("[test.cpp:12]: (error) Possible null pointer dereference: Q\n", errout.str());
-
-        // Ticket #2052 (false positive for 'else continue;')
-        checkNullPointer("void f() {\n"
-                         "    for (int x = 0; x < 5; ++x) {"
-                         "        int *p = 0;\n"
-                         "        if (a(x)) p=b(x);\n"
-                         "        else continue;\n"
-                         "        *p = 0;\n"
-                         "    }\n"
-                         "}");
-        ASSERT_EQUALS("", errout.str());
-
-        // function pointer..
-        checkNullPointer("void foo()\n"
-                         "{\n"
-                         "    void (*f)();\n"
-                         "    f = 0;\n"
-                         "    f();\n"
-                         "}\n");
-        ASSERT_EQUALS("[test.cpp:5]: (error) Possible null pointer dereference: f\n", errout.str());
-
-        checkNullPointer("static void foo()\n"
-                         "{\n"
-                         "    int *p = 0;\n"
-                         "    int *p2 = 0;\n"
-                         "    int r = *p;\n"
-                         "    int r2 = *p2;\n"
-                         "}\n");
-        ASSERT_EQUALS("[test.cpp:5]: (error) Null pointer dereference\n"
-                      "[test.cpp:6]: (error) Null pointer dereference\n", errout.str());
-
-        // loops..
-        checkNullPointer("void f() {\n"
-                         "    int *p = 0;\n"
-                         "    for (int i = 0; i < 10; ++i) {\n"
-                         "        int x = *p + 1;\n"
-                         "    }\n"
-                         "}\n");
-        ASSERT_EQUALS("[test.cpp:4]: (error) Possible null pointer dereference: p\n", errout.str());
-
-        checkNullPointer("void f(int a) {\n"
-                         "    const char *p = 0;\n"
-                         "    if (a) {\n"
-                         "    	 p = \"abcd\";\n"
-                         "    }\n"
-                         "    for (int i = 0; i < 3; i++) {\n"
-                         "        if (a && (p[i] == '1'));\n"
-                         "    }\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-    }
-
-    void nullpointer7()
-    {
-        checkNullPointer("void foo()\n"
-                         "{\n"
-                         "  wxLongLong x = 0;\n"
-                         "  int y = x.GetValue();\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-    }
-
-    void nullpointer8()
-    {
-        checkNullPointer("void foo()\n"
-                         "{\n"
-                         "  const char * x = 0;\n"
-                         "  strdup(x);\n"
-                         "}\n");
-        ASSERT_EQUALS("[test.cpp:4]: (error) Possible null pointer dereference: x\n", errout.str());
-        checkNullPointer("void foo()\n"
-                         "{\n"
-                         "  char const * x = 0;\n"
-                         "  strdup(x);\n"
-                         "}\n");
-        ASSERT_EQUALS("[test.cpp:4]: (error) Possible null pointer dereference: x\n", errout.str());
-    }
-
-    void nullpointer9() //#ticket 1778
-    {
-        checkNullPointer("void foo()\n"
-                         "{\n"
-                         "  std::string * x = 0;\n"
-                         "  *x = \"test\";\n"
-                         "}\n");
-        ASSERT_EQUALS("[test.cpp:4]: (error) Possible null pointer dereference: x\n", errout.str());
-    }
-
-    // Check if pointer is null and the dereference it
-    void nullpointer10()
-    {
-        checkNullPointer("void foo(char *p) {\n"
-                         "    if (!p) {\n"
-                         "    }\n"
-                         "    *p = 0;\n"
-                         "}\n");
-        ASSERT_EQUALS("[test.cpp:4]: (error) Possible null pointer dereference: p\n", errout.str());
-
-        checkNullPointer("void foo(abc *p) {\n"
-                         "    if (!p) {\n"
-                         "    }\n"
-                         "    else if (!p->x) {\n"
-                         "    }\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        checkNullPointer("void foo(char *p) {\n"
-                         "    if (!p) {\n"
-                         "        abort();\n"
-                         "    }\n"
-                         "    *p = 0;\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        checkNullPointer("void foo(char *p) {\n"
-                         "    if (!p) {\n"
-                         "        throw x;\n"
-                         "    }\n"
-                         "    *p = 0;\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        checkNullPointer("void foo() {\n"
-                         "    if (!p) {\n"
-                         "        switch (x) { }\n"
-                         "    }\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-
-        // This is why this check can't be used on the simplified token list
-        checkNullPointer("void f(Foo *foo) {\n"
-                         "    if (!dynamic_cast<bar *>(foo)) {\n"
-                         "        *foo = 0;\n"
-                         "    }\n"
-                         "}\n");
-        ASSERT_EQUALS("", errout.str());
-    }
-
     void checkUninitVar(const char code[])
     {
         // Tokenize..
@@ -1528,7 +890,7 @@ private:
                        "}\n");
         ASSERT_EQUALS("", errout.str());
 
-        checkNullPointer("void f(int a)\n"
+        checkUninitVar("void f(int a)\n"
                        "{\n"
                        "    if (a) {\n"
                        "        char *p;\n"