Hi James,> And thus, if ORC is at that level (probably is?), I think it should justgo in there with all the rest of them. ORC is definitely not at that level yet - the attached patch was for a prototype of the APIs and lacks many features. If it goes in, I expect it to change reasonably quickly over the next few weeks/months as features are added and bugs uncovered and fixed. After that I would expect it to calm down a bit, but it'll be a while before it could approach the kind of stability described in the document you posted for review. I'll keep an eye on this thread tomorrow and see what other people have to say as they get back from vacation, but I suspect the next step for the ORC APIs will be to go in to llvm/include/llvm-c/unstable. They can live there while they're under development and move to llvm-c if/when we're ready. Cheers, Lang. On Mon, Sep 7, 2015 at 10:41 PM, James Y Knight <jyknight at google.com> wrote:> On Sep 8, 2015, at 12:55 AM, Eric Christopher via llvm-dev < > llvm-dev at lists.llvm.org> wrote: > > > > On Mon, Sep 7, 2015 at 5:37 PM Lang Hames <lhames at gmail.com> wrote: > >> Hi Jauhien, >> >> A few people have requested a C API for ORC. I don't think ORC's ready >> for a stable C API, but I'm not opposed to providing C bindings that will >> probably be reasonably stable in practice (though with no guarantees). I've >> actually already knocked up some trivial prototype bindings for Hayden >> Livingston that could serve as a base (see attached). >> >> The next question is where unstable bindings should live. Juergen, Eric, >> anyone else who wants to weigh in: I looked back over the C API thread, but >> I don't think we settled on a home for this kind of thing. Any thoughts? I >> could see either introducing a new include directory (something along the >> lines of include/llvm/llvm-c-bindings) or a new c-bindings project on >> llvm.org. The former would put all LLVM developers on the hook for >> maintaining the bindings, the latter would leave maintenance to users of >> the bindings project, and any volunteers. I prefer the second option: I >> don't think core developers should be on the hook for maintaining unstable >> bindings - that kind of special treatment should be reserved for the stable >> API. >> >> > We hadn't figured out a location. I was the one that wanted to move stable > to a new directory and Jim wanted to move unstable. I think either will > work ultimately, just a matter of personal preference in the "when do we > count restart". > > That said, as long as you put a comment at the top saying that the ORC > bindings are unstable and put them in a new file I'm not opposed to just > putting them in llvm-c for now. I also don't think I'm going to win the > argument of "stable moves" so if you'd like to make a new unstable > directory I'm perfectly happy with that direction too. > > Thoughts? > > > +1 to putting it in llvm-c for now (but also for good). > > I really think the existing LLVM-C APIs should all be considered > "reasonably stable in practice", not "absolutely 100% stable forever". > "Reasonably stable in practice" means to me: if you need to remove a > function, then, ok, do that. But make a reasonable effort to avoid doing so > first, for users' sake. And don't change the ABI of existing functions. > > And thus, if ORC is at that level (probably is?), I think it should just > go in there with all the rest of them. > > BTW, have a patch: http://reviews.llvm.org/D12685 saying that in more > words. >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20150907/8e8dff99/attachment.html>
On Sep 8, 2015, at 2:07 AM, Lang Hames <lhames at gmail.com> wrote:> Hi James, > > > And thus, if ORC is at that level (probably is?), I think it should just go in there with all the rest of them. > > ORC is definitely not at that level yet - the attached patch was for a prototype of the APIs and lacks many features. If it goes in, I expect it to change reasonably quickly over the next few weeks/months as features are added and bugs uncovered and fixed. After that I would expect it to calm down a bit, but it'll be a while before it could approach the kind of stability described in the document you posted for review.I had actually meant the underlying system, not the LLVM-C wrapper itself. But, that's actually a good point which is not addressed by the draft policy: *when* do stability rules kick in? Instantaneously? A couple weeks of "oops" buffer time? The next release? Clearly, while a complex addition to the LLVM-C wrapper API is under development, its interface really cannot possibly be stable yet -- no matter what the underlying API's stability is, or what the intended stability is. Saying that a stability policy doesn't apply until the next llvm release is attractive (and, is what the policy for IR changes says about IR compatibility). But my understanding is that a lot of people using llvm just work off of llvm trunk (and even make release branches from arbitrary points between releases), so that may not be the best policy? Having the "unstable" directory be where under-active-development C API wrappers go while under development, and then graduating out when they're "done" makes some sense. That is: "unstable" should not be considered a final resting place for "unstable" APIs -- it's just for complex additions to the wrappers that are currently under development. I'm a bit wary, because it seems like it could still end up a place where people will add stuff (better safe than sorry, so put it in unstable!), and then it will just get left there and never moved out, because that would take energy, and people are busy, and forget. So then you end up with a random subset of the API sitting in "unstable", despite being essentially unchanged for the last year or five. And of course other projects will have grown to depend on it by then, too. Perhaps if the "install" build target excluded installing the headers from "unstable", too; that'd at least be a bit of incentive to move them out when they're ready, since it'll be annoying that they're not available in installed headers.
Hi All, Belatedly circling back to this, with apologies for not being able to keep up at the time. I expect the ORC C APIs to take at least a couple of release cycles to get ironed out to the point where they could be considered stable. It would be wonderful if it happened more quickly, and maybe we'll get lucky, but I'm not counting on it. :) That said - the best way to get things moving is to have people use them and discover where the issues are. So with that in mind: Did we read a consensus on a reasonable staging area? Would it be reasonable to put the prototype APIs in "include/llvm-c-unstable"? Cheers, Lang. On Tue, Sep 8, 2015 at 9:11 AM, James Y Knight <jyknight at google.com> wrote:> On Sep 8, 2015, at 2:07 AM, Lang Hames <lhames at gmail.com> wrote: > > Hi James, > > > > > And thus, if ORC is at that level (probably is?), I think it should > just go in there with all the rest of them. > > > > ORC is definitely not at that level yet - the attached patch was for a > prototype of the APIs and lacks many features. If it goes in, I expect it > to change reasonably quickly over the next few weeks/months as features are > added and bugs uncovered and fixed. After that I would expect it to calm > down a bit, but it'll be a while before it could approach the kind of > stability described in the document you posted for review. > > I had actually meant the underlying system, not the LLVM-C wrapper itself. > > But, that's actually a good point which is not addressed by the draft > policy: *when* do stability rules kick in? Instantaneously? A couple weeks > of "oops" buffer time? The next release? Clearly, while a complex addition > to the LLVM-C wrapper API is under development, its interface really cannot > possibly be stable yet -- no matter what the underlying API's stability is, > or what the intended stability is. > > Saying that a stability policy doesn't apply until the next llvm release > is attractive (and, is what the policy for IR changes says about IR > compatibility). But my understanding is that a lot of people using llvm > just work off of llvm trunk (and even make release branches from arbitrary > points between releases), so that may not be the best policy? > > Having the "unstable" directory be where under-active-development C API > wrappers go while under development, and then graduating out when they're > "done" makes some sense. That is: "unstable" should not be considered a > final resting place for "unstable" APIs -- it's just for complex additions > to the wrappers that are currently under development. > > I'm a bit wary, because it seems like it could still end up a place where > people will add stuff (better safe than sorry, so put it in unstable!), and > then it will just get left there and never moved out, because that would > take energy, and people are busy, and forget. So then you end up with a > random subset of the API sitting in "unstable", despite being essentially > unchanged for the last year or five. And of course other projects will have > grown to depend on it by then, too. > > Perhaps if the "install" build target excluded installing the headers from > "unstable", too; that'd at least be a bit of incentive to move them out > when they're ready, since it'll be annoying that they're not available in > installed headers. > >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20151016/246d9474/attachment.html>