> On Apr 25, 2017, at 11:24 AM, Roman Levenstein via swift-dev > <swift-dev@swift.org> wrote: > > >> On Apr 25, 2017, at 11:18 AM, Jordan Rose <jordan_r...@apple.com> wrote: >> >> I believe these are interposition points for things like dtrace, and also >> useful for Roman's experiments with nonatomic retain counting. Roman, do you >> know? > > I had a chat with Slava yesterday and explained it to him. > > But basically, these are for the special calling convention to be used for > invocation of often used runtime entry points (e.g. reference counting > functions like swift_retain). This calling convention is not enabled by > default yet. But the idea is that it provides more callee-saved registers > thus giving the caller more registers that can be used without spilling them > around the calls of such a runtime entry. And wrappers are required because > otherwise dyld (the dynamic linker) in certain situations clobbers some of > these callee-saved registers.
Can we document this in ./docs somewhere? > > -Roman > >> >> (JoeG would know too but he's on vacation.) >> >> Jordan >> >> >>> On Apr 24, 2017, at 17:15, Slava Pestov via swift-dev <swift-dev@swift.org> >>> wrote: >>> >>> Hi all, >>> >>> Now that we’re using swiftcc, does IRGen still need to emit the swift_rt_* >>> wrappers around runtime calls? They look like no-ops at this point since >>> the runtime entry points themselves should be swiftcc with the callee save >>> variant? >>> >>> Slava >>> _______________________________________________ >>> swift-dev mailing list >>> swift-dev@swift.org >>> https://lists.swift.org/mailman/listinfo/swift-dev >> > > _______________________________________________ > swift-dev mailing list > swift-dev@swift.org > https://lists.swift.org/mailman/listinfo/swift-dev _______________________________________________ swift-dev mailing list swift-dev@swift.org https://lists.swift.org/mailman/listinfo/swift-dev
