[clang] [llvm] [Clang][PCH] Use metadata for embedding AST (PR #214135)

[Fangrui Song via llvm-commits]

MaskRay wrote:

+329 -19 doesn't feel right to me....

> To avoid the size restriction that may be imposed by the address spaces of the target

What's the size restriction?

https://github.com/llvm/llvm-project/pull/214135