llvm-project

6ce13ae1 - [clang][bytecode] Always track item types in InterpStack (#151088)

[clang][bytecode] Always track item types in InterpStack (#151088) This has been a long-standing problem, but we didn't use to call the destructors of items on the stack unless we explicitly `pop()` or `discard()` them. When interpretation was interrupted midway-through (because something failed), we left `Pointer`s on the stack. Since all `Block`s track what `Pointer`s point to them (via a doubly-linked list in the `Pointer`), that meant we potentially leave deallocated pointers in that list. We used to work around this by removing the `Pointer` from the list before deallocating the block. However, we now want to track pointers to global blocks as well, which poses a problem since the blocks are never deallocated and thus those pointers are always left dangling. I've tried a few different approaches to fixing this but in the end I just gave up on the idea of never knowing what items are in the stack. We already have an `ItemTypes` vector that we use for debugging assertions. This patch simply enables this vector unconditionally and uses it in the abort case to properly `discard()` all elements from the stack. That's a little sad IMO but I don't know of another way of solving this problem. As expected, this is a slight hit to compile times: https://llvm-compile-time-tracker.com/compare.php?from=574d0a92060bf4808776b7a0239ffe91a092b15d&to=0317105f559093cfb909bfb01857a6b837991940&stat=instructions:u