[clang] [clang][analyzer] Extend lifetime of dynamic extent information (PR #163562)

[Donát Nagy via cfe-commits]

https://github.com/NagyDonat commented:

Thanks for working on this issue, I'm very happy to see this patch!

What happens when you have a symbolic region (e.g. allocated by `malloc`) with a dynamic extent, then both the region and its extent symbol become inaccessible at the same time? Will you prolong the lifetime of the extent symbol? Is it eventually "garbage-collected"?

My first instinct is that instead of `markAllDynamicExtentLive` you would need a loop that marks the dynamic extent live only if the region itself is live. (Or non-symbolic -- by the way, can non-symbolic regions have a symbolic dynamic extent?)

https://github.com/llvm/llvm-project/pull/163562