C++: Respond to review comments.

Author: MathiasVP

cpp/ql/src/Likely Bugs/OO/UnsafeUseOfThis.qhelp

@@ -5,11 +5,11 @@
 
 
 <overview>
-<p>This rule finds calls to pure virtual member functions in constructors and destructors. Such calls do not perform virtual dispatch, and can cause undefined behavior.</p>
+<p>This rule finds calls to pure virtual member functions in constructors and destructors. When executing the body of a constructor of class <code>T</code>, the virtual table of <code>T</code> refers to the virtual table of one of <code>T</code>'s base classes. This can produce unexpected behavior, including program abort that can lead to denial of service attacks. The same problem exists during destruction of an object.</p>
 
 </overview>
 <recommendation>
-<p>Do not rely on virtual dispatch in constructors and destructors. Instead, each class should be responsible for acquiring and releasing its resources.</p>
+<p>Do not rely on virtual dispatch in constructors and destructors. Instead, each class should be responsible for acquiring and releasing its resources. If a base class needs to refer to a derived class during initialization, use the Dynamic Binding During Initialization idiom.</p>
 
 </recommendation>
 <example><sample src="UnsafeUseOfThis.cpp" />
@@ -19,14 +19,11 @@
 </example>
 <references>
 
-<li>
-  <a href="https://isocpp.org/wiki/faq/strange-inheritance#calling-virtuals-from-ctors">When my base class’s constructor calls a virtual function on its this object, why doesn’t my derived class’s override of that virtual function get invoked?</a>
+<li>ISO C++ FAQ: <a href="https://isocpp.org/wiki/faq/strange-inheritance#calling-virtuals-from-ctors">When my base class's constructor calls a virtual function on its this object, why doesn't my derived class's override of that virtual function get invoked?</a>
 </li>
-<li>
-  <a href="https://wiki.sei.cmu.edu/confluence/display/cplusplus/OOP50-CPP.+Do+not+invoke+virtual+functions+from+constructors+or+destructors">OOP50-CPP. Do not invoke virtual functions from constructors or destructors</a>
+<li>SEI CERT C++ Coding Standard <a href="https://wiki.sei.cmu.edu/confluence/display/cplusplus/OOP50-CPP.+Do+not+invoke+virtual+functions+from+constructors+or+destructors">OOP50-CPP. Do not invoke virtual functions from constructors or destructors</a>
 </li>
-<li>
-  <a href="https://scc.ustc.edu.cn/zlsc/sugon/intel/ssadiag_docs/pt_reference/references/sc_cpp_virtual_call_in_ctor.htm">Virtual function call in constructor</a>
+<li>ISO C++ FAQ: <a href="https://isocpp.org/wiki/faq/strange-inheritance#calling-virtuals-from-ctor-idiom">Okay, but is there a way to simulate that behavior as if dynamic binding worked on the this object within my base class's constructor?</a>
 </li>
 
 

cpp/ql/src/Likely Bugs/OO/UnsafeUseOfThis.ql

@@ -1,6 +1,6 @@
 /**
  * @name Unsafe use of this in constructor
- * @description A call to a pure virtual function using a this
+ * @description A call to a pure virtual function using a 'this'
  *              pointer of an object that is under construction
  *              may lead to undefined behavior.
  * @kind path-problem