[compiler-rt] [llvm] [TypeProf][InstrFDO]Omit vtable symbols in indexed profiles by default (PR #96520)

[Mingming Liu via llvm-commits]

minglotus-6 wrote:

> Perhaps make the option default to true initially?

Hmm, I'm hoping build tools or profile processing tools can pick up `--keep-vtable-symbols=false` naturally to save the need to update them individually. Let me know if there is a scenario or example we'd prefer to override the option in separate changes!
*  With `--keep-vtable-symbols=false`,  there won't be issues when merging old profiles (generated before this change) and new profiles (generated with this change).

> and with this change we won't emit either (iiuc).

Correct!

> That's a fairly small decrease, but otoh I don't see a big downside since the names are there in the raw profile which is often available.

I gathered profiles from 4 other binaries. The decrease is smaller than 1% across binaries.

|binary  |Diff|profile size before (in MB)|profile size after (in MB)|
|--------|----|---------------------------|--------------------------|
|search1 |0.8%|337                        |334                       |
|search2 |0.9%|330                        |327                       |
|database|0.5%|256.7                      |255.3                     |
|network |0.6%|98.4                       |97.8                      |




https://github.com/llvm/llvm-project/pull/96520