[clang] [clang][DebugInfo] Attach `DISubprogram` to additional call variants (PR #166202)

[Alexander Kornienko via cfe-commits]

alexfh wrote:

> Does google use call site information (does it care about entry_values, or do any extra stuff with the info)?

@dwblaikie or @labath should know the answer.

> I wonder if it would be useful to add a flag to disable call site info for your builds (if such a flag doesn't already exist)?

I think regardless of the debug information completeness improvement, the 1.5%+ increase may be problematic in some cases. We probably need a flag to mitigate this increase without disabling debug information altogether. If there's already a flag that controls the information being added by this change (or a reasonable superset of it), we may be able to suggest it as a workaround for teams who have to squeeze their binaries into hard size limits.

https://github.com/llvm/llvm-project/pull/166202