cycle collector (#14071)

* figured out the wrong cycle trace proc problem
* cycle collector/break refactorings and minor improvements

lib/system/cyclebreaker.nim

@@ -52,6 +52,8 @@ That seems acceptable, no leak is produced. This implies that the standard
 depth-first traversal suffices.
 
 ]#
+include cellseqs_v2
+
 const
   colGreen = 0b000
   colYellow = 0b001
@@ -72,57 +74,9 @@ proc nimIncRefCyclic(p: pointer) {.compilerRtl, inl.} =
   inc h.rc, rcIncrement
 
 type
-  CellTuple = (ptr pointer, PNimType)
-  CellArray = ptr UncheckedArray[CellTuple]
-  CellSeq = object
-    len, cap: int
-    d: CellArray
-
   GcEnv = object
     traceStack: CellSeq
 
-# ------------------- cell seq handling --------------------------------------
-
-proc add(s: var CellSeq, c: ptr pointer; t: PNimType) {.inline.} =
-  if s.len >= s.cap:
-    s.cap = s.cap * 3 div 2
-    when defined(useMalloc):
-      var d = cast[CellArray](c_malloc(uint(s.cap * sizeof(CellTuple))))
-    else:
-      var d = cast[CellArray](alloc(s.cap * sizeof(CellTuple)))
-    copyMem(d, s.d, s.len * sizeof(CellTuple))
-    when defined(useMalloc):
-      c_free(s.d)
-    else:
-      dealloc(s.d)
-    s.d = d
-    # XXX: realloc?
-  s.d[s.len] = (c, t)
-  inc(s.len)
-
-proc init(s: var CellSeq, cap: int = 1024) =
-  s.len = 0
-  s.cap = cap
-  when defined(useMalloc):
-    s.d = cast[CellArray](c_malloc(uint(s.cap * sizeof(CellTuple))))
-  else:
-    s.d = cast[CellArray](alloc(s.cap * sizeof(CellTuple)))
-
-proc deinit(s: var CellSeq) =
-  when defined(useMalloc):
-    c_free(s.d)
-  else:
-    dealloc(s.d)
-  s.d = nil
-  s.len = 0
-  s.cap = 0
-
-proc pop(s: var CellSeq): (ptr pointer, PNimType) =
-  result = s.d[s.len-1]
-  dec s.len
-
-# ----------------------------------------------------------------------------
-
 proc trace(p: pointer; desc: PNimType; j: var GcEnv) {.inline.} =
   when false:
     cprintf("[Trace] desc: %p %p\n", desc, p)