Can compiler throw out unused code

[LemonParty]

Hello.

Can compiler throw out from unit unused functions? Unused methods from class or record?

[Thaddy]

Yes, the compiler can do that, but only for a whole program and with whole program optimization, a.k.a WPO and which is usually a three pass effort.
This is usually only worth it when the program is finished and debugged.
The above is the case for unused methods in class or record. It optimizes away the vmt's.
See https://wiki.freepascal.org/Whole_Program_Optimization
The compiler itself is compiled that way.

What the compiler always does at -O2 or higher is eliminate dead code, but the vmt's will then still be fully intact.

[marcov]

But only virtual/overriden methods are in a VMT. The rest can be eliminated if unused.

[LemonParty]

Thank you, Thaddy. I will look the article.