Fix 7684: ValueFlow: function call 'X::GetSize()' (#3984)

* Improve getting function to calculate the return

* Add test

* Format

* Move to cpp to avoid FP

* Format

cli/threadexecutor.cpp

@@ -552,3 +552,7 @@ unsigned int STDCALL ThreadExecutor::threadProc(LogWriter* logWriter)
     return result;
 }
 #endif
+
+bool ThreadExecutor::isEnabled() {
+    return true;
+}

cli/threadexecutor.h

@@ -84,10 +84,7 @@ public:
     /**
      * @return true if support for threads exist.
      */
-    static bool isEnabled() {
+    static bool isEnabled();
-        return true;
-    }
-
 };
 
 /// @}

lib/valueflow.cpp

@@ -6972,7 +6972,15 @@ static bool isKnown(const Token * tok)
 static void valueFlowFunctionReturn(TokenList *tokenlist, ErrorLogger *errorLogger)
 {
     for (Token *tok = tokenlist->back(); tok; tok = tok->previous()) {
-        if (tok->str() != "(" || !tok->astOperand1() || !tok->astOperand1()->function())
+        if (tok->str() != "(" || !tok->astOperand1())
+            continue;
+
+        const Function* function = nullptr;
+        if (Token::Match(tok->previous(), "%name% ("))
+            function = tok->previous()->function();
+        else
+            function = tok->astOperand1()->function();
+        if (!function)
             continue;
 
         if (tok->hasKnownValue())
@@ -6997,7 +7005,6 @@ static void valueFlowFunctionReturn(TokenList *tokenlist, ErrorLogger *errorLogg
         }
 
         // Get scope and args of function
-        const Function * const function = tok->astOperand1()->function();
         const Scope * const functionScope = function->functionScope;
         if (!functionScope || !Token::simpleMatch(functionScope->bodyStart, "{ return")) {
             if (functionScope && tokenlist->getSettings()->debugwarnings && Token::findsimplematch(functionScope->bodyStart, "return", functionScope->bodyEnd))

test/testbufferoverrun.cpp

@@ -186,6 +186,7 @@ private:
         TEST_CASE(array_index_59); // #10413
         TEST_CASE(array_index_60); // #10617, #9824
         TEST_CASE(array_index_61); // #10621
+        TEST_CASE(array_index_62); // #7684
         TEST_CASE(array_index_multidim);
         TEST_CASE(array_index_switch_in_for);
         TEST_CASE(array_index_for_in_for);   // FP: #2634
@@ -1766,6 +1767,21 @@ private:
         ASSERT_EQUALS("", errout.str());
     }
 
+    void array_index_62()
+    {
+        check("struct X {\n"
+              "    static int GetSize() {return 11;}\n"
+              "};\n"
+              "char f() {\n"
+              "    char buf[10]= {0};\n"
+              "    for(int i = 0; i < X::GetSize(); ++i) \n"
+              "       buf[i] = 0;\n"
+              "    return buf[0];\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:7]: (error) Array 'buf[10]' accessed at index 10, which is out of bounds.\n",
+                      errout.str());
+    }
+
     void array_index_multidim() {
         check("void f()\n"
               "{\n"