refactor coroutine lowering and tasks

src/runtime/scheduler_coroutines.go

@@ -2,103 +2,8 @@
 
 package runtime
 
-// This file implements the Go scheduler using coroutines.
-// A goroutine contains a whole stack. A coroutine is just a single function.
-// How do we use coroutines for goroutines, then?
-//   * Every function that contains a blocking call (like sleep) is marked
-//     blocking, and all it's parents (callers) are marked blocking as well
-//     transitively until the root (main.main or a go statement).
-//   * A blocking function that calls a non-blocking function is called as
-//     usual.
-//   * A blocking function that calls a blocking function passes its own
-//     coroutine handle as a parameter to the subroutine. When the subroutine
-//     returns, it will re-insert the parent into the scheduler.
-// Note that we use the type 'task' to refer to a coroutine, for compatibility
-// with the task-based scheduler. A task type here does not represent the whole
-// task, but just the topmost coroutine. For most of the scheduler, this
-// difference doesn't matter.
-//
-// For more background on coroutines in LLVM:
-// https://llvm.org/docs/Coroutines.html
-
-import "unsafe"
-
-// A coroutine instance, wrapped here to provide some type safety. The value
-// must not be used directly, it is meant to be used as an opaque *i8 in LLVM.
-type task uint8
-
-//go:export llvm.coro.resume
-func (t *task) resume()
-
-//go:export llvm.coro.destroy
-func (t *task) destroy()
-
-//go:export llvm.coro.done
-func (t *task) done() bool
-
-//go:export llvm.coro.promise
-func (t *task) _promise(alignment int32, from bool) unsafe.Pointer
-
-// Get the state belonging to a task.
-func (t *task) state() *taskState {
-	return (*taskState)(t._promise(int32(unsafe.Alignof(taskState{})), false))
-}
-
-func makeGoroutine(uintptr) uintptr
-
-// Compiler stub to get the current goroutine. Calls to this function are
-// removed in the goroutine lowering pass.
-func getCoroutine() *task
-
-// setTaskStatePtr is a helper function to set the current .ptr field of a
-// coroutine promise.
-func setTaskStatePtr(t *task, value unsafe.Pointer) {
-	t.state().ptr = value
-}
-
-// getTaskStatePtr is a helper function to get the current .ptr field from a
-// coroutine promise.
-func getTaskStatePtr(t *task) unsafe.Pointer {
-	if t == nil {
-		blockingPanic()
-	}
-	return t.state().ptr
-}
-
-// yield suspends execution of the current goroutine
-// any wakeups must be configured before calling yield
-func yield()
-
 // getSystemStackPointer returns the current stack pointer of the system stack.
 // This is always the current stack pointer.
 func getSystemStackPointer() uintptr {
 	return getCurrentStackPointer()
 }
-
-func fakeCoroutine(dst **task) {
-	*dst = getCoroutine()
-	for {
-		yield()
-	}
-}
-
-func getFakeCoroutine() *task {
-	// this isnt defined behavior, but this is what our implementation does
-	// this is really a horrible hack
-	var t *task
-	go fakeCoroutine(&t)
-
-	// the first line of fakeCoroutine will have completed by now
-	return t
-}
-
-// noret is a placeholder that can be used to indicate that an async function is not going to directly return here
-func noret()
-
-func getParentHandle() *task
-
-func llvmCoroRefHolder() {
-	noret()
-	getParentHandle()
-	getCoroutine()
-}