[lldb] Adapt shared cache ObjC class metadata extraction for long term growth (#167579)
On Apple's platforms, the size of the shared cache grows steadily. As it
grows, so does its list of ObjC classes. LLDB currently accepts an upper
limit to the number of classes when it extracts the class information.
Every few years we will hit the limit and increase the upper limit of
classes.
This approach is fundamentally unsustainable. On top of needing to
manually adjust the number every few years, our current method requires
us to allocate memory in the inferior process. On macOS this is usually
not a problem, but on embedded devices there is usually a limit to how
much memory a process can allocate before they are killed by the OS.
My solution involves running the metadata extraction logic multiple
times. I've added a new parameter to our utility function `start_idx`
that keeps track of where it stopped during the previous run so that it
may pick up again where it stopped.
rdar://91398396
llvm-project
ec4207ba - [lldb] Adapt shared cache ObjC class metadata extraction for long term growth (#167579)
