[llvm] [llubi] Add support for captures (PR #201170)

[Yingwei Zheng via llvm-commits]

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dtcxzyw wrote:

Yeah. We can decide whether to assign a new tag for the pointer parameter **_at the beginning of the function call_**. We cannot predict whether it will be captured via the memory after this point. If no component is dropped via the `captures` attribute, we reuse the tag.

https://github.com/llvm/llvm-project/pull/201170