The "don't link" test application takes almost 25 minutes to compile in 2019-06 for the iOS 64 bit Device Release configuration, compared to about 3 minutes in 2019-02.
The bulk of the time is spent in Xamarin.iOS.dll.
2019-02:
14:59:29.1461680 Mono Ahead of Time compiler - compiling assembly /Users/alexander/dev/xamarin-macios/xamarin-macios-master/tests/xharness/tmp-test-dir/dont link587/obj/iPhone/Release64-unified/mtouch-cache/3-Build/Xamarin.iOS.dll (Aufgaben-ID: 112)
14:59:29.1462630 AOTID F8D95594-6050-30F7-D04C-E63BFD3C081E (Aufgaben-ID: 112)
14:59:29.1462820 Executing opt: "/Users/alexander/dev/xamarin-macios/xamarin-macios-master/_ios-build/Library/Frameworks/Xamarin.iOS.framework/Versions/git/LLVM/bin/opt" -f -O2 -disable-tail-calls -o "/Users/alexander/dev/xamarin-macios/xamarin-macios-master/tests/xharness/tmp-test-dir/dont link587/obj/iPhone/Release64-unified/mtouch-cache/arm64/Xamarin.iOS.dll.s.opt.bc" "/Users/alexander/dev/xamarin-macios/xamarin-macios-master/tests/xharness/tmp-test-dir/dont link587/obj/iPhone/Release64-unified/mtouch-cache/arm64/Xamarin.iOS.dll.s.bc" (Aufgaben-ID: 112)
14:59:29.1463120 Executing llc: "/Users/alexander/dev/xamarin-macios/xamarin-macios-master/_ios-build/Library/Frameworks/Xamarin.iOS.framework/Versions/git/LLVM/bin/llc" -march=aarch64 -asm-verbose=false -mtriple=arm64-ios -disable-gnu-eh-frame -enable-mono-eh-frame -mono-eh-frame-symbol=_mono_aot_Xamarin_iOS_eh_frame -disable-tail-calls -relocation-model=static -filetype=obj -o "/Users/alexander/dev/xamarin-macios/xamarin-macios-master/tests/xharness/tmp-test-dir/dont link587/obj/iPhone/Release64-unified/mtouch-cache/arm64/Xamarin.iOS.dll-llvm.o" "/Users/alexander/dev/xamarin-macios/xamarin-macios-master/tests/xharness/tmp-test-dir/dont link587/obj/iPhone/Release64-unified/mtouch-cache/arm64/Xamarin.iOS.dll.s.opt.bc" (Aufgaben-ID: 112)
14:59:29.1463290 Compiled: 93058/93058 (Aufgaben-ID: 112)
14:59:29.1463520 Output file: '/Users/alexander/dev/xamarin-macios/xamarin-macios-master/tests/xharness/tmp-test-dir/dont link587/obj/iPhone/Release64-unified/mtouch-cache/arm64/Xamarin.iOS.dll.s'. (Aufgaben-ID: 112)
14:59:29.1463670 Linking symbol: '_mono_aot_module_Xamarin_iOS_info'. (Aufgaben-ID: 112)
14:59:29.1463910 LLVM output file: '/Users/alexander/dev/xamarin-macios/xamarin-macios-master/tests/xharness/tmp-test-dir/dont link587/obj/iPhone/Release64-unified/mtouch-cache/arm64/Xamarin.iOS.dll-llvm.o'. (Aufgaben-ID: 112)
14:59:29.1464060 JIT time: 17264 ms, Generation time: 158812 ms, Assembly+Link time: 0 ms. (Aufgaben-ID: 112)
2019-06:
14:34:14.7011550 JIT time: 16719 ms, Generation time: 1334801 ms, Assembly+Link time: 10 ms. (Aufgaben-ID: 112)
The "don't link" test application takes almost 25 minutes to compile in 2019-06 for the iOS 64 bit Device Release configuration, compared to about 3 minutes in 2019-02.
The bulk of the time is spent in Xamarin.iOS.dll.
2019-02:
2019-06: