ARC: ported the GC tests over to --gc:arc

lib/core/runtime_v2.nim

@@ -135,6 +135,18 @@ proc GC_ref*[T](x: ref T) =
   ## New runtime only supports this operation for 'ref T'.
   if x != nil: nimIncRef(cast[pointer](x))
 
+template GC_fullCollect* =
+  ## Forces a full garbage collection pass. With ``--gc:arc`` a nop.
+  discard
+
+template setupForeignThreadGc* =
+  ## With ``--gc:arc`` a nop.
+  discard
+
+template tearDownForeignThreadGc* =
+  ## With ``--gc:arc`` a nop.
+  discard
+
 proc isObj(obj: PNimType, subclass: cstring): bool {.compilerRtl, inl.} =
   proc strstr(s, sub: cstring): cstring {.header: "<string.h>", importc.}
 

lib/system.nim

@@ -250,18 +250,19 @@ const ThisIsSystem = true
 proc internalNew*[T](a: var ref T) {.magic: "New", noSideEffect.}
   ## Leaked implementation detail. Do not use.
 
-proc new*[T](a: var ref T, finalizer: proc (x: ref T) {.nimcall.}) {.
-  magic: "NewFinalize", noSideEffect.}
-  ## Creates a new object of type ``T`` and returns a safe (traced)
-  ## reference to it in ``a``.
-  ##
-  ## When the garbage collector frees the object, `finalizer` is called.
-  ## The `finalizer` may not keep a reference to the
-  ## object pointed to by `x`. The `finalizer` cannot prevent the GC from
-  ## freeing the object.
-  ##
-  ## **Note**: The `finalizer` refers to the type `T`, not to the object!
-  ## This means that for each object of type `T` the finalizer will be called!
+when not defined(gcDestructors):
+  proc new*[T](a: var ref T, finalizer: proc (x: ref T) {.nimcall.}) {.
+    magic: "NewFinalize", noSideEffect.}
+    ## Creates a new object of type ``T`` and returns a safe (traced)
+    ## reference to it in ``a``.
+    ##
+    ## When the garbage collector frees the object, `finalizer` is called.
+    ## The `finalizer` may not keep a reference to the
+    ## object pointed to by `x`. The `finalizer` cannot prevent the GC from
+    ## freeing the object.
+    ##
+    ## **Note**: The `finalizer` refers to the type `T`, not to the object!
+    ## This means that for each object of type `T` the finalizer will be called!
 
 when defined(nimV2):
   proc reset*[T](obj: var T) {.magic: "Destroy", noSideEffect.}

lib/system/strmantle.nim

@@ -304,3 +304,12 @@ proc `$`*(x: uint64): string {.noSideEffect, raises: [].} =
     let half = i div 2
     # Reverse
     for t in 0 .. half-1: swap(result[t], result[i-t-1])
+
+when defined(gcDestructors):
+  proc GC_getStatistics*(): string =
+    result = "[GC] total memory: "
+    result.addInt getTotalMem()
+    result.add "\n[GC] occupied memory: "
+    result.addInt getOccupiedMem()
+    result.add '\n'
+    #"[GC] cycle collections: " & $gch.stat.cycleCollections & "\n" &