similar to: llvm.coro.size - why can't we call it from outside the coroutine?

cc llvm-dev On Thu, Jul 21, 2016 at 9:57 AM, Vadim Chugunov <vadimcn at gmail.com> wrote: > Hi Gor, > Does you design support resumption with parameter(s)? (such as Python's > generator.send(x)). I suppose the "promise" could be used for passing data > both ways, but if that's the plan, please mention this explicitly in the > design doc. > Also, how is

I'm going to show the same function, first normally, and then as a coroutine, and show how gdb can see the variable when it's a normal function, but not when it's a coroutine. I'd like to understand if this can be improved. I'm trying to debug a real world problem, but the lack of debug info on variables in coroutines is making it difficult. Should I file a bug? Is this a

Hi all: I've included below a brief description of coroutine related optimization passes and some questions/thoughts related to them. Looking forward to your feedback, comments and questions. Thank you! Roadmap: ======== 1) Get agreement on coroutine representation and overall direction. .. repeat 1) until happy http://lists.llvm.org/pipermail/llvm-dev/2016-June/100838.html (Initial)

Hi, I would like to propose a potential solution to a bug that involves coroutine and pthread_self(). Description of the bug can be found in https://bugs.llvm.org/show_bug.cgi?id=47833. Below is a summary: pthread_self() from glibc is defined with "__attribute__ ((__const__))". The const attribute tells the compiler that it does not read nor write any global state and hence always

Hi all: Below is a proposal to add experimental coroutine support to LLVM. Though this proposal is motivated primarily by the desire to support C++ Coroutines [1], the llvm representation is language neutral and can be used to support coroutines in other languages as well. Clang + llvm coroutines allows you to take this code: generator<int> range(int from, int to) { for(int i =

Hello all, It's been a month since my previous email on the topic, and since then I've done some initial work on porting the coroutines passes to the new pass manager. In total there are 6 patches -- that's a lot to review, so allow me to introduce the changes being made in each of them. # What's finished In these first 6 patches, I focused on lowering coroutine intrinsics

Hi Eli: >> Block1: >> %0 = call i8 coro.suspend() >> switch i8 %0, label suspend1 [i8 0 %return] ; or icmp + br i1 >> Suspend1: >> switch i8 %0, label %resume1 [i8 1 %destroy1] ; or icmp + br i1 >> >> This doesn't look right: intuitively the suspend happens after the return >> block runs. Perhaps, but, that is not the intended

(Dropped llvm-dev by accident. Putting it back) HI Eli: >> coro.barrier() doesn't work: if the address of the alloca doesn't escape, >> alias analysis will assume the barrier can't read or write the value of >> the alloca, so the barrier doesn't actually block code movement. Got it. I am new to this and learning a lot over the course of this thread. Thank you

I have this input IR in the final cleanup block of my coroutine: // call the free function call fastcc void %22(%Allocator* %20, %"[]u8"* byval %4), !dbg !244 // based on whether this is an early return or a normal return, we want to // either return to the caller, or resume the handle of the awaiter br i1 %19, label %Resume, label %Return, !dbg !244 Resume:

Hi Eli: Thank you very much for your comments! >> If you need some sort of unusual control flow construct, make it a >> proper terminator instruction I would love to. I was going by the advice in "docs/ExtendingLLVM.rst": "WARNING: Adding instructions changes the bitcode format, and it will take some effort to maintain compatibility with the previous

> On Mar 19, 2018, at 3:44 PM, Brian Gesiak <modocache at gmail.com> wrote: > > Hello all! > (+cc Vedant Kumar, who I've been told knows a lot about UBSan!) > > I am trying to fix an assert that occurs when the transforms in llvm/lib/Transforms/Coroutines are applied to LLVM IR that has been generated with UBSan enabled -- specifically, '-fsanitize=null'. >

I think I got it. Original model (with coro.fork and two-way coro.suspend) will work with a tiny tweak. In the original model, I was replacing coro.suspend with br %return in original function. The problem was coming from potential phi-nodes introduces into return block during optimizations. Let's make sure that there is only entry into the return block. In the original model, ReturnBB had

It makes sense that you would be able to do this: %save1 = llvm.coro.save() %unused = musttail call llvm.coro.resume(%some_handle) %x = llvm.coro.suspend() ... But the docs for musttail say: > The call must immediately precede a ret instruction, or a pointer bitcast followed by a ret instruction. Should this be amended to allow a musttail to be followed by llvm.coro.suspend() ? Regards,

Hi Sanjoy, >> I'm not familiar with fiber-type APIs, but I assume fiber_fork is like >> setjmp, in that it can "return twice"? Yes, user-mode stack switching API are somewhat similar to setjmp. Here are links to a doc page and implementation, just in case you are curious: http://www.boost.org/doc/libs/1_59_0/libs/context/doc/html/context/context.html

(Forwarding response to llvm-dev with Dave's permission.) > On Jan 10, 2018, at 11:19 AM, David Blaikie <dblaikie at gmail.com> wrote: > Optnone stops these things, doesnt it? But then, as you say, you'd have to find some way to tunnels true optnone through to the coroutine expansion pass. > Right. More importantly, we definitely want to allow internal optimization of the

Hello all! (+cc Vedant Kumar, who I've been told knows a lot about UBSan!) I am trying to fix an assert that occurs when the transforms in llvm/lib/Transforms/Coroutines are applied to LLVM IR that has been generated with UBSan enabled -- specifically, '-fsanitize=null'. You can see an example of the assert in this 26-line C++ file here: https://godbolt.org/g/Gw9UZq Note that

Hi David: >> How do you deal with basic blocks which appear to be used by multiple parts >> of the coroutine? We handled this in WinEHPrepare by cloning any BBs which >> were shared. I experimented with several approaches, but, cloning ended up being the simplest and most reliable. Suspend points express three different control flows that can happen at the suspend point: a

That all makes sense. I don't think the name "synthetic" is all that intuitive, though. Enum attributes are pretty cheap, maybe we should try to use a name closer to what we're trying to implement? For example, we could add a new "coroutine_foo" attribute for every coroutine style we implement. We would have analysis helper functions to answer questions like "is

Thanks, that was a really helpful suggestion. If you're curious- here are some of the high cost areas: ===-------------------------------------------------------------------------=== DWARF Emission ===-------------------------------------------------------------------------=== Total Execution Time: 2.0117 seconds (2.0185 wall clock) ---User Time---

Hi Sanjoy: >> Now in the above CFG %val can be folded to 10, but in reality you need >> a PHI of 10 and 20 Quick answer: folding %val to 10 is OK, but, I would prefer it to be 'undef' or even catch it in the verifier as it is a programmer/frontend error. Details are in the second half of my reply. I would like to start with the thought experiment you suggested, as it might