I'm trying to do some performance assessment with the Time Profiler in Instruments. It's pretty clear that some traces are being scrambled by inlining and/or tail call optimization, to the extent that it's hard to tell where time is really being consumed.
Is there any way to turn these optimizations off globally? I know this would have its own biasing effect on the execution profile, but it seems like those distortions would be easier to deal with than the ones introduced by inlining and tail calls. And of course, I want to keep all other optimizations.
This WWDC 2015 talk and this 2017 article by Jordan Morgan both suggest adding
-fno-optimize-sibling-calls to CFLAGS (and by extension, I assume
-fno-inline-functions for inlining), but this no longer seems to have any effect. These are Clang flags; was the Swift compiler previously based on Clang and is now separate?