From aeb573d5296920461782dac177cbad84e0a8ebae Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <hyd_danmar@users.sourceforge.net>
Date: Wed, 4 Feb 2009 18:49:19 +0000
Subject: [PATCH] returning pointer to local array

---
 src/checkother.cpp | 53 ++++++++++++++++++++++++++++++++++++++++++++++
 src/checkother.h   |  3 +++
 src/errormessage.h |  9 ++++++++
 test/testother.cpp | 29 +++++++++++++++++++++++++
 tools/errmsg.cpp   |  1 +
 5 files changed, 95 insertions(+)

diff --git a/src/checkother.cpp b/src/checkother.cpp
index 34f1395cd..33430b139 100644
--- a/src/checkother.cpp
+++ b/src/checkother.cpp
@@ -21,6 +21,7 @@
 //---------------------------------------------------------------------------
 #include "checkother.h"
 #include "errormessage.h"
+#include <algorithm>
 #include <list>
 #include <map>
 #include <sstream>
@@ -813,3 +814,55 @@ void CheckOther::strPlusChar()
         }
     }
 }
+
+
+
+
+
+void CheckOther::returnPointerToStackData()
+{
+    bool infunc = false;
+    int indentlevel = 0;
+    std::list<unsigned int> arrayVar;
+    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
+    {
+        if (!infunc && Token::simpleMatch(tok, ") {"))
+        {
+            infunc = true;
+            indentlevel = 0;
+            arrayVar.clear();
+        }
+
+        if (infunc)
+        {
+            if (tok->str() == "{")
+                ++indentlevel;
+            else if (tok->str() == "}")
+            {
+                --indentlevel;
+                if (indentlevel <= 0)
+                    infunc = false;
+                continue;
+            }
+
+            // Declaring a local array..
+            if (Token::Match(tok, "[;{}] %type% %var% ["))
+            {
+                arrayVar.push_back(tok->tokAt(2)->varId());
+            }
+
+            // Return pointer to local array variable..
+            if (Token::Match(tok, "return %var% ;"))
+            {
+                unsigned int varid = tok->next()->varId();
+                if (varid > 0 && std::find(arrayVar.begin(), arrayVar.end(), varid) != arrayVar.end())
+                    ErrorMessage::returnLocalVariable(_errorLogger, _tokenizer, tok);
+            }
+        }
+
+        // Declaring array variable..
+
+
+    }
+}
+
diff --git a/src/checkother.h b/src/checkother.h
index a365b041a..d2e4b0206 100644
--- a/src/checkother.h
+++ b/src/checkother.h
@@ -65,6 +65,9 @@ public:
     /** str plus char */
     void strPlusChar();
 
+    /** Returning pointer to local data */
+    void returnPointerToStackData();
+
 #ifndef UNIT_TESTING
 private:
 #endif
diff --git a/src/errormessage.h b/src/errormessage.h
index 402deb78c..b8cc5fa75 100644
--- a/src/errormessage.h
+++ b/src/errormessage.h
@@ -332,5 +332,14 @@ public:
         return true;
     }
 
+    static void returnLocalVariable(ErrorLogger *logger, const Tokenizer *tokenizer, const Token *Location)
+    {
+        _writemsg(logger, tokenizer, Location, "always", "Returning pointer to local array variable", "returnLocalVariable");
+    }
+    static bool returnLocalVariable()
+    {
+        return true;
+    }
+
 };
 #endif
diff --git a/test/testother.cpp b/test/testother.cpp
index c7fc79f20..1aeb59523 100644
--- a/test/testother.cpp
+++ b/test/testother.cpp
@@ -48,6 +48,8 @@ private:
         TEST_CASE(strPlusChar1);     // "/usr" + '/'
         TEST_CASE(strPlusChar2);     // "/usr" + ch
         TEST_CASE(strPlusChar3);     // ok: path + "/sub" + '/'
+
+        TEST_CASE(returnLocalVariable1);
     }
 
     void check(const char code[])
@@ -230,6 +232,33 @@ private:
         ASSERT_EQUALS(std::string(""), errout.str());
     }
 
+
+
+    void retVar(const char code[])
+    {
+        // Tokenize..
+        Tokenizer tokenizer;
+        std::istringstream istr(code);
+        tokenizer.tokenize(istr, "test.cpp");
+        tokenizer.setVarId();
+
+        // Clear the error buffer..
+        errout.str("");
+
+        // Check for redundant code..
+        CheckOther checkOther(&tokenizer, Settings(), this);
+        checkOther.returnPointerToStackData();
+    }
+
+    void returnLocalVariable1()
+    {
+        retVar("char *foo()\n"
+               "{\n"
+               "    char str[100] = {0};\n"
+               "    return str;\n"
+               "\n");
+        ASSERT_EQUALS(std::string("[test.cpp:4]: (always) Returning pointer to local array variable\n"), errout.str());
+    }
 };
 
 REGISTER_TEST(TestOther)
diff --git a/tools/errmsg.cpp b/tools/errmsg.cpp
index 716df2502..b36636068 100644
--- a/tools/errmsg.cpp
+++ b/tools/errmsg.cpp
@@ -102,6 +102,7 @@ int main()
     err.push_back(Message("variableScope", Message::never, "The scope of the variable %1 can be limited", "varname"));
     err.push_back(Message("conditionAlwaysTrueFalse", Message::style, "Condition is always %1", "truefalse"));
     err.push_back(Message("strPlusChar", Message::always, "Unusual pointer arithmetic"));
+    err.push_back(Message("returnLocalVariable", Message::always, "Returning pointer to local array variable"));
 
     // Generate code..
     std::cout << "Generate code.." << std::endl;