[swift-dev] swift driver on Darwin

[Jordan Rose]

> On Dec 21, 2016, at 11:11, Joe Groff <jgroff at apple.com> wrote:
> 
> 
>> On Dec 19, 2016, at 10:23 AM, Jordan Rose via swift-dev <swift-dev at swift.org> wrote:
>> 
>> [+swift-dev, swift-build-dev] Once upon a time I think I had the idea that swiftc should be useful independent of having a Clang install, but we've long since given up on that on Linux and it's not such an interesting configuration on Darwin. I don't have strong objections to merging them, though there might be some trickiness around picking the right profiling libraries (if Swift and Clang are ever out of sync we would ideally prefer Swift's).
>> 
>> The other thing floating around here is something Daniel Dunbar once brought up: usually each compiler wants to own the linker invocation, but then you have a hard time linking object files from multiple compilers using the same linker invocation. (Consider linking with clang vs. clang++, and then needing to add custom arguments for Swift.) It would be nice™ if instead a build system could ask "what additional linker flags do you need before/after your object files?", and put that in as necessary.
> 
> Could something like the autolinking mechanism be used to pull in necessary runtime object files, such as the swift_begin/end.o stubs, without direct help from the driver?

I'm not sure, but it's probably very linker-dependent, since we actually need the bracketing. This also applies to non-autolinking things like, say, enabling or disabling dead code stripping, but those flags can usually appear anywhere in the list.

Jordan