[Lldb-commits] [PATCH] D117139: [lldb] Copy ScriptedInterface object instance to a new StructuredData object

[Pavel Labath via Phabricator via lldb-commits]

labath added a comment.

I'd like to remind everyone of a not-very-widely-known, but incredibly nifty feature of std::shared_ptr, called "aliasing". It allows one to create a shared_ptr which points to one object, but deletes a completely different object when it goes out of scope. It works like so:

  std::shared_ptr<A> a = std::make_shared<A>(...); // or whatever
  std::shared_ptr<B> b(a, getB(a)); // will point to a B, but call `delete A` when it goes out of scope

The model use case is when the first object is a subobject (field) of the second one (so we'd have `struct A { B b; ... }; and `getB(a)` would be `&a->b`), but that is not a a requirement. B can be a completely arbitrary object -- the only requirement is that B remains live for as long as A is around.

Now, I don't understand this code well enough to say whether that could/should be used here, but the (few) parts which I did understand led me to think that there are some subobjects (in the broadest sense of the word) being passed around, and so I have a feeling we should at least consider this option -- it seems like it would be better to pass around objects with explicit ownership semantics instead of raw pointers.


Repository:
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  https://reviews.llvm.org/D117139/new/

https://reviews.llvm.org/D117139