aprantl added inline comments.
================
Comment at: lldb/source/Symbol/CompilerType.cpp:35
+ bool unused;
+ if (GetTypeSystemGraveyard().Lookup(m_type_system, unused)) {
+ lldbassert(false && "CompilerType belongs to deleted Typesystem");
----------------
hawkinsw wrote:
> 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!
Yes, CompilerType could be used on any thread and this will not catch a
use-after-free if the TypeSystem is deleted between the IsValid check and its
use.
A solution would be to store a TypeSystemSP/WP in CompilerType, but I'm
expecting this to be rather expensive. The intention of this patch is as a
bug-finding tool. It's not intended to make holding on to CompilerType objects
safe. That said, I'm open to explore ideas for how to efficiently make this
safe in a future patch.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D136650/new/
https://reviews.llvm.org/D136650
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