revert #21799 and #21802 which don't pass the tests (#21804)

* Revert "ORC: make rootsThreshold thread local [backport] (#21799)"

This reverts commit b74d49c037.

* Revert "fixes #21752 [backport] (#21802)"

This reverts commit d0c62fa169.

compiler/types.nim

@@ -396,9 +396,9 @@ proc canFormAcycleAux(marker: var IntSet, typ: PType, startId: int): bool =
       result = true
     elif not containsOrIncl(marker, t.id):
       for i in 0..<t.len:
-        result = canFormAcycleAux(marker, t[i], abs startId)
+        result = canFormAcycleAux(marker, t[i], startId)
         if result: return
-      if t.n != nil: result = canFormAcycleNode(marker, t.n, abs startId)
+      if t.n != nil: result = canFormAcycleNode(marker, t.n, startId)
     # Inheritance can introduce cyclic types, however this is not relevant
     # as the type that is passed to 'new' is statically known!
     # er but we use it also for the write barrier ...
@@ -415,10 +415,7 @@ proc isFinal*(t: PType): bool =
 proc canFormAcycle*(typ: PType): bool =
   var marker = initIntSet()
   let t = skipTypes(typ, abstractInst+{tyOwned}-{tyTypeDesc})
-  # startId begins with a negative value that is only in the first recursion
-  # and the following recursions set to its real value. This fixes
-  # bug #21753:
-  result = canFormAcycleAux(marker, t, -t.id)
+  result = canFormAcycleAux(marker, t, t.id)
 
 proc mutateTypeAux(marker: var IntSet, t: PType, iter: TTypeMutator,
                    closure: RootRef): PType

lib/system/orc.nim

@@ -350,7 +350,7 @@ const
 when defined(nimStressOrc):
   const rootsThreshold = 10 # broken with -d:nimStressOrc: 10 and for havlak iterations 1..8
 else:
-  var rootsThreshold {.threadvar.}: int
+  var rootsThreshold = defaultThreshold
 
 proc partialCollect(lowMark: int) =
   when false:
@@ -392,13 +392,13 @@ proc collectCycles() =
     # of the cycle collector's effectiveness:
     # we're effective when we collected 50% or more of the nodes
     # we touched. If we're effective, we can reset the threshold:
-    if j.keepThreshold and rootsThreshold <= 0:
+    if j.keepThreshold and rootsThreshold <= defaultThreshold:
       discard
     elif j.freed * 2 >= j.touched:
       when not defined(nimFixedOrc):
         rootsThreshold = max(rootsThreshold div 3 * 2, 16)
       else:
-        rootsThreshold = 0
+        rootsThreshold = defaultThreshold
       #cfprintf(cstderr, "[collectCycles] freed %ld, touched %ld new threshold %ld\n", j.freed, j.touched, rootsThreshold)
     elif rootsThreshold < high(int) div 4:
       rootsThreshold = rootsThreshold * 3 div 2
@@ -411,7 +411,7 @@ proc registerCycle(s: Cell; desc: PNimTypeV2) =
   if roots.d == nil: init(roots)
   add(roots, s, desc)
 
-  if roots.len >= rootsThreshold+defaultThreshold:
+  if roots.len >= rootsThreshold:
     collectCycles()
   when logOrc:
     writeCell("[added root]", s, desc)
@@ -427,7 +427,7 @@ proc GC_enableOrc*() =
   ## Enables the cycle collector subsystem of `--gc:orc`. This is a `--gc:orc`
   ## specific API. Check with `when defined(gcOrc)` for its existence.
   when not defined(nimStressOrc):
-    rootsThreshold = 0
+    rootsThreshold = defaultThreshold
 
 proc GC_disableOrc*() =
   ## Disables the cycle collector subsystem of `--gc:orc`. This is a `--gc:orc`

tests/arc/tasyncleak.nim

@@ -1,5 +1,5 @@
 discard """
-  outputsub: "(allocCount: 4050, deallocCount: 4048)"
+  outputsub: "(allocCount: 4302, deallocCount: 4300)"
   cmd: "nim c --gc:orc -d:nimAllocStats $file"
 """
 

tests/arc/topt_no_cursor.nim

@@ -1,6 +1,6 @@
 discard """
   nimoutFull: true
-  cmd: '''nim c -r --warnings:off --hints:off --mm:arc --expandArc:newTarget --expandArc:delete --expandArc:p1 --expandArc:tt --hint:Performance:off --assertions:off --expandArc:extractConfig --expandArc:mergeShadowScope --expandArc:check $file'''
+  cmd: '''nim c -r --warnings:off --hints:off --gc:arc --expandArc:newTarget --expandArc:delete --expandArc:p1 --expandArc:tt --hint:Performance:off --assertions:off --expandArc:extractConfig --expandArc:mergeShadowScope --expandArc:check $file'''
   nimout: '''
 --expandArc: newTarget