[clang-tools-extra] [clang-tidy] Add `bugprone-pointer-arithmetic-on-polymorphic-object` check (PR #91951)
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cfe-commits at lists.llvm.org
Wed May 29 07:02:42 PDT 2024
================
@@ -0,0 +1,60 @@
+.. title:: clang-tidy - bugprone-pointer-arithmetic-on-polymorphic-object
+
+bugprone-pointer-arithmetic-on-polymorphic-object
+=================================================
+
+Finds pointer arithmetic performed on classes that declare a virtual function.
+
+Pointer arithmetic on polymorphic objects where the pointer's static type is
+different from its dynamic type is undefined behavior, as the two types can
+have different sizes.
+Finding pointers where the static type contains a virtual member function is a
+good heuristic, as the pointer is likely to point to a different, derived class.
+
+Example:
+
+.. code-block:: c++
+
+ struct Base {
+ virtual void ~Base();
+ };
+
+ struct Derived : public Base {};
+
+ void foo() {
+ Base *b = new Derived[10];
+
+ b += 1;
+ // warning: pointer arithmetic on class that declares a virtual function,
+ // which can result in undefined behavior if the pointee is a
+ // different class
+
+ delete[] static_cast<Derived*>(b);
+ }
+
+This check corresponds to the SEI Cert rule `CTR56-CPP: Do not use pointer arithmetic on polymorphic objects <https://wiki.sei.cmu.edu/confluence/display/cplusplus/CTR56-CPP.+Do+not+use+pointer+arithmetic+on+polymorphic+objects>`_.
----------------
EugeneZelenko wrote:
Links to rules are usually placed at the end.
https://github.com/llvm/llvm-project/pull/91951
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