There's definitely a runtime, but I *think* you can avoid actually using it by being very careful with your data structures. ARC means that classes obviously trigger it, and I think it *might* be involved resizing arrays and strings (they do some tricks behind the scenes, but I can't remember what).
So... only use structs and don't resize anything? I'm not sure... I think there might be some cases where protocols or indirect enums get stored as references, and that might involve the runtime as well. Maybe you should go over to the evolution list and suggest a "no runtime" compiler flag or source code annotation, which disallows anything which would use the runtime. I believe there could be advantages outside of running on bare-metal, since you could use it to get the compiler to yell at you for doing overhead-inducing stuff in a loop, for example. Anyway, best of luck :-) - Dave Sweeris > On Aug 9, 2016, at 15:10, Rick Mann via swift-users <swift-users@swift.org> > wrote: > > Is it possible to use Swift for bare-metal programming on embedded devices? > These devices usually have memory-mapped registers that are read and written > to affect the operation of the device. Some can be quite small (e.g. 8-bit > registers, simple single physical memory address space), and others quite > robust (full 32- or 64-bit machines with MMUs, etc.). > > But bare metal development for all of them starts with emitting code with > "raw" packaging (no Mach or ELF headers, etc.), and the ability to read and > write specific memory addresses. > > For the smaller devices, runtime library overhead is a concern (mostly due to > code size). Is it possible to write swift code with no runtime library? I > think this is possible in Rust (came up on another list). > > Most such development is done in C, and there is always some form of library > to take on some of the standard library tasks and stub out basic IO, as well > as filling in gaps for larger variable sizes not directly supported by the > hardware. > > I imagine there's some runtime support for ARC, although maybe that's handled > entirely in the compilation phase? > > Anyway, I'd appreciate someone more knowledgable letting me know if this is > something I should experiment with. Thanks! > > -- > Rick Mann > rm...@latencyzero.com > > > _______________________________________________ > swift-users mailing list > swift-users@swift.org > https://lists.swift.org/mailman/listinfo/swift-users _______________________________________________ swift-users mailing list swift-users@swift.org https://lists.swift.org/mailman/listinfo/swift-users
