[swift-dev] Faster debug builds?
zarzycki at icloud.com
Sun Aug 6 13:10:50 CDT 2017
Unless I’m missing a build-script flag, it seems to me that compiling the Swift stdlib with the unoptimized debug swift compiler takes about 15 minutes on a fast machine. Other than forcing the type checker to be optimized, what if any tricks can I use to building the stdlib faster with the debug compiler? Is there a way to tell Clang to enable the inliner and only the inliner during -O0 builds? I have an anecdotal experiment that suggests that this would yield appreciably faster Swift stdlib builds with the debug compiler (and selfishly speaking, I can tolerate the minor impact on debugging that inlining does to otherwise unoptimized code).
 – If one force inlines LLVM’s casting logic and associated callbacks (like classof() and getKind()), then the Swift stdlib builds 18% faster on my machine with the debug Swift compiler. One can imagine how much faster the whole stdlib would compile if all trivial functions were inlined automatically.
More information about the swift-dev