[clang] [Serialization] Load Specializations Lazily (PR #76774)

[Chuanqi Xu via cfe-commits]

ChuanqiXu9 wrote:

> As far as I can tell from [#76774 (comment)](https://github.com/llvm/llvm-project/pull/76774#issuecomment-1914177330) above, the last push only changed the default value of `LoadExternalSpecializationsLazily`. In that case, my test results from [#76774 (comment)](https://github.com/llvm/llvm-project/pull/76774#issuecomment-1912182171) remain fully valid, especially
> 
> > Switching the new `LoadExternalSpecializationsLazily` to disabled by default (somehow the argument didn't work on its own) instead crashes, most of the cases involving `MultiOnDiskHashTable`. I suspect some kind of memory error maybe?

No, this newest patch changes  besides changing the default value. For example, https://github.com/llvm/llvm-project/pull/76774/commits/22c9d1145eb57d9c2cb2ef490b7c474598dd5d12#diff-125f472e690aa3d973bc42aa3c5d580226c5c47661551aca2889f960681aa64dR232-R237 now we won't write specializations into the hash table, while the original patch tries to load all the decls from the consumers' side only. This patch touches the producer's side.

Maybe I shouldn't push force to make the history clear..

https://github.com/llvm/llvm-project/pull/76774