ticket 155

lib/checkother.cpp

@@ -79,24 +79,25 @@ void CheckOther::checkFflushOnInputStream()
 }
 
 
-void CheckOther::checkSizeofWithSilentArrayPointer()
+void CheckOther::checkSizeofForArrayParameter()
 {
     for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
     {
         if (Token::Match(tok, "sizeof ( %var% )") || Token::Match(tok, "sizeof %var% "))
         {
             int tokIdx = 1;
-            if (tok->tokAt(tokIdx)->str() == "(") {
+            if (tok->tokAt(tokIdx)->str() == "(")
+            {
                 ++tokIdx;
             }
             if (tok->tokAt(tokIdx)->varId() > 0)
             {
-                const Token *declTok = Token::findmatch(_tokenizer->tokens(), "%varid% [", tok->tokAt(tokIdx)->varId());
+                const Token *declTok = Token::findmatch(_tokenizer->tokens(), "%varid%", tok->tokAt(tokIdx)->varId());
                 if (declTok)
                 {
-                    if (!(Token::simpleMatch(declTok->next()->link(), "] = {")) && !(Token::simpleMatch(declTok->next()->link(), "] ;")))
+                    if ((Token::simpleMatch(declTok->next(), "[")) && !(Token::simpleMatch(declTok->next()->link(), "] = {")) && !(Token::simpleMatch(declTok->next()->link(), "] ;")))
                     {
-                        sizeofWithSilentArrayPointerError(tok);
+                        sizeofForArrayParameterError(tok);
                     }
                 }
             }
@@ -482,10 +483,21 @@ void CheckOther::invalidScanf()
     }
 }
 
-void CheckOther::sizeofWithSilentArrayPointerError(const Token *tok)
+void CheckOther::sizeofForArrayParameterError(const Token *tok)
 {
-    reportError(tok, Severity::error, "sizeofwithsilentarraypointer", "silent pointer of array is passed as parameter to the function sizeof.");
+    reportError(tok, Severity::error,
-
+                "sizeofwithsilentarraypointer", "Using sizeof for array given as function argument "
+                "returns the size of pointer.\n"
+                "Giving array as function parameter and then using sizeof-operator for the array "
+                "argument. In this case the sizeof-operator returns the size of pointer (in the "
+                "  system). It does not return the size of the whole array in bytes as might be "
+                "expected. For example, this code:\n"
+                "     int f(char a[100]) {\n"
+                "         return sizeof(a);\n"
+                "     }\n"
+                " returns 4 (in 32-bit systems) or 8 (in 64-bit systems) instead of 100 (the "
+                "size of the array in bytes)."
+               );
 }
 void CheckOther::invalidScanfError(const Token *tok)
 {

lib/checkother.h

@@ -62,7 +62,7 @@ public:
         checkOther.sizeofCalculation();
         checkOther.checkRedundantAssignmentInSwitch();
         checkOther.checkAssignmentInAssert();
-        checkOther.checkSizeofWithSilentArrayPointer();
+        checkOther.checkSizeofForArrayParameter();
     }
 
     /** @brief Run checks against the simplified token list */
@@ -171,8 +171,8 @@ public:
     /** @brief %Check for filling zero bytes with memset() */
     void checkMemsetZeroBytes();
 
-    /** @brief %Check if parameter of sizeof() is typed as a silent pointer of array */
+    /** @brief %Check for using sizeof with array given as function argument */
-    void checkSizeofWithSilentArrayPointer();
+    void checkSizeofForArrayParameter();
 
     // Error messages..
     void cstyleCastError(const Token *tok);
@@ -197,7 +197,7 @@ public:
     void misusedScopeObjectError(const Token *tok, const std::string &varname);
     void catchExceptionByValueError(const Token *tok);
     void memsetZeroBytesError(const Token *tok, const std::string &varname);
-    void sizeofWithSilentArrayPointerError(const Token *tok);
+    void sizeofForArrayParameterError(const Token *tok);
 
     void getErrorMessages(ErrorLogger *errorLogger, const Settings *settings)
     {
@@ -210,7 +210,7 @@ public:
         c.mathfunctionCallError(0);
         c.fflushOnInputStreamError(0, "stdin");
         c.misusedScopeObjectError(NULL, "varname");
-        c.sizeofWithSilentArrayPointerError(0);
+        c.sizeofForArrayParameterError(0);
 
         // style/warning
         c.cstyleCastError(0);
@@ -253,7 +253,7 @@ public:
                "* using fflush() on an input stream\n"
                "* scoped object destroyed immediately after construction\n"
                "* assignment in an assert statement\n"
-               "* silent array pointer as parameter of sizeof\n"
+               "* sizeof for array given as function argument\n"
 
                // style
                "* C-style pointer cast in cpp file\n"

test/testother.cpp

@@ -120,7 +120,7 @@ private:
         checkOther.sizeofCalculation();
         checkOther.checkRedundantAssignmentInSwitch();
         checkOther.checkAssignmentInAssert();
-        checkOther.checkSizeofWithSilentArrayPointer();
+        checkOther.checkSizeofForArrayParameter();
 
         // Simplify token list..
         tokenizer.simplifyTokenList();
@@ -1718,19 +1718,29 @@ private:
               "    std::cout << sizeof(a) / sizeof(int) << std::endl;\n"
               "}\n"
              );
-        ASSERT_EQUALS("[test.cpp:2]: (error) silent pointer of array is passed as parameter to the function sizeof.\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:2]: (error) Using sizeof for array given as "
+                      "function argument returns the size of pointer.\n", errout.str());
 
         check("void f( int a[]) {\n"
               "    std::cout << sizeof a / sizeof(int) << std::endl;\n"
               "}\n"
              );
-        ASSERT_EQUALS("[test.cpp:2]: (error) silent pointer of array is passed as parameter to the function sizeof.\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:2]: (error) Using sizeof for array given as "
+                      "function argument returns the size of pointer.\n", errout.str());
 
         check("void f( int a[3] ) {\n"
               "    std::cout << sizeof(a) / sizeof(int) << std::endl;\n"
               "}\n"
              );
-        ASSERT_EQUALS("[test.cpp:2]: (error) silent pointer of array is passed as parameter to the function sizeof.\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:2]: (error) Using sizeof for array given as "
+                      "function argument returns the size of pointer.\n", errout.str());
+
+        check("void f(int *p) {\n"
+              "    p[0] = 0;\n"
+              "    sizeof(p);\n"
+              "}\n"
+             );
+        ASSERT_EQUALS("", errout.str());
 
     }