[all-commits] [llvm/llvm-project] b171eb: [lldb] Defend against infinite recursion in GetCla...

[Jonas Devlieghere via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: b171ebbfffcd4b8d923734dd0fc077b02a6fe3f7
      https://github.com/llvm/llvm-project/commit/b171ebbfffcd4b8d923734dd0fc077b02a6fe3f7
  Author: Jonas Devlieghere <jonas at devlieghere.com>
  Date:   2025-06-24 (Tue, 24 Jun 2025)

  Changed paths:
    M lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp
    M lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.h

  Log Message:
  -----------
  [lldb] Defend against infinite recursion in GetClassDescriptor (#145396)

We defend against a direct cycle where a base class ValueObject is its
own parent, but not against a longer base cycle. This cycle requires
that some value's Type includes a base class, and that base class is in
a class hierarchy that cycles back to the original base class.

I wrote a test case that creates a cycle in the class hierarchy by
dynamically overwriting the superclass of an object, but I can't
reproduce the crash. I can't think of any other way to make a real
object that behaves that way. Maybe is a type system problem in making
up the type for whatever type we're trying to ingest here.

While unsatisfying, without a reproducer this is the best we can do for
now.

rdar://140293233



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