ThinLTO is there. I think that should settle the final/virtual debate

[ZombineDev via Digitalmars-d]

On Sunday, 4 December 2016 at 01:36:50 UTC, deadalnix wrote:
> First, presentation:
> https://www.youtube.com/watch?v=9OIEZAj243g
>
> Some of this is available in LLVM today, and everything 
> presented here will be in 4.0 . The long story short: ThinLTO 
> can do most of what LTO does but with a price that is much 
> closer to the one of a regular build than the one of a classic 
> LTO build.
>
> LTO optimization can devirtualize all function that do not need 
> to be virtual, and even use profile infos to speculatively 
> devirtualize - aka JVM grade devirtualization.
>
> I would love to see this leveraged to finally put to rest the 
> final vs virtual debate. If we use this tech properly, 
> everything that do not need to be virtual can be finalized - 
> except across shared object, which shouldn't be too much of an 
> issue in practice.

ldc-1.1.0-beta5 --help | grep -A2 lto
   -flto             - Set LTO mode, requires linker support
     =full           - Merges all input into a single module
     =thin           - Parallel importing and codegen (faster than 
'full')
   -flto-binary=<file>              - Set the linker LTO plugin 
library file (e.g. LLVMgold.so (Unixes) or libLTO.dylib (Darwin))
   -fprofile-instr-generate=<filename>       - Generate 
instrumented code to collect execution counts (e.g. for PGO)
   -fprofile-instr-use=<filename>           - Use instrumentation 
data for profile-guided optimization