Mirror of forum.nim-lang.org

5629 :: [C backend] Environment of closure on stack

• foldl (orginal) [2019-12-03T15:35:20+01:00] view original

  Hi all,

  Env-s are allocated on heap by newObj. Is it possible to put them on stack? There are some cons, such as closure can't live out of a function's scope. But, in the case of truly embedded systems with only several KiB RAM with -gc:regions, env-s on stack is good enough, ^_^

---

• mratsim (orginal) [2019-12-03T15:46:55+01:00] view original

  I also require more ways to manipulate closures or being able to implement my own from macros.

  This would allow me to emulate the OpenMP API or the parallel API in my multithreading runtime.

  I still have to explore the liftLocal pragma or the owner macro though (https://forum.nim-lang.org/t/4031#25106 / https://github.com/nim-lang/Nim/pull/8253)

---

• foldl (orginal) [2019-12-06T11:00:09+01:00] view original

  If gc:none, linking will fail with undefined newObj.

  Is it a good idea to put env on stack for gc:none?

---

• mratsim (orginal) [2019-12-06T12:36:40+01:00] view original

  In the end, I used explicit captures with the following syntax:

  block:
      proc main() =
        init(Weave)
        
        parallelFor i in 0 ..< 100:
          log("%d (thread %d)\n", i, myID())
        
        exit(Weave)
      
      # main()
    
    block: # Capturing outside scope
      proc main2() =
        init(Weave)
        
        var a = 100
        var b = 10
        parallelFor i in 0 ..< 10:
          captures: {a, b}
          log("a+b+i = %d (thread %d)\n", a+i, myID())
        
        exit(Weave)
      
      
      
      # main2()
    
    
    block: # Nested loops
      proc main3() =
        init(Weave)
        
        parallelFor i in 0 ..< 4:
          parallelFor j in 0 ..< 8:
            captures: {i}
            log("Matrix[%d, %d] (thread %d)\n", i, j, myID())
        
        exit(Weave)
      
      main3()
  Run

  From Weave multithreading runtime

---