hawkinsw added a comment. There are *so* many reasons that I love this patch.
First and foremost: I am a professor of computer science at University of Cincinnati and teaching Programming Languages this semester and I am about to teach *this very technique* for protecting against use-after-free errors. Having seen this patch I now have a great example of where it is used in real life! So, thank you! Second, I have left some comments but please take what I said with a grain of salt. I hope that it is helpful and not a waste of time. Thank you! Will ================ Comment at: lldb/source/Symbol/CompilerType.cpp:35 + bool unused; + if (GetTypeSystemGraveyard().Lookup(m_type_system, unused)) { + lldbassert(false && "CompilerType belongs to deleted Typesystem"); ---------------- I am sorry if this is obvious, but is `CompilerType` used in a multithreaded environment? So, is there a possibility that we could pass the check on line 32 but become invalid by the use of `m_type_system` here and fall victim to an attempt (in `Lookup`, perhaps?) to dereference a `NULL` pointer? Again, I am sorry if that is a stupid question! ================ Comment at: lldb/source/Symbol/CompilerType.cpp:36 + if (GetTypeSystemGraveyard().Lookup(m_type_system, unused)) { + lldbassert(false && "CompilerType belongs to deleted Typesystem"); + return false; ---------------- I know that this is a nit, but should we write `TypeSystem`? ================ Comment at: lldb/source/Symbol/TypeSystem.cpp:22 + // Intentionally leaked to avoid C++ destructor ordering issue. + static TypeSystemSet *g_typesystem_graveyard = new TypeSystemSet(); + return *g_typesystem_graveyard; ---------------- I spent *way* too long researching to make sure that this initialization is thread safe and wanted to drop a link here in case anyone is wondering the same thing: [C++ standard: stmt.dcl para 3, sentence 3](http://eel.is/c++draft/stmt.dcl#3.sentence-3) CHANGES SINCE LAST ACTION https://reviews.llvm.org/D136650/new/ https://reviews.llvm.org/D136650 _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits