fixes #3558

lib/system/alloc.nim

@@ -301,13 +301,14 @@ proc pageAddr(p: pointer): PChunk {.inline.} =
   result = cast[PChunk](cast[ByteAddress](p) and not PageMask)
   #sysAssert(Contains(allocator.chunkStarts, pageIndex(result)))
 
-proc writeFreeList(a: MemRegion) =
-  var it = a.freeChunksList
-  c_fprintf(stdout, "freeChunksList: %p\n", it)
-  while it != nil:
-    c_fprintf(stdout, "it: %p, next: %p, prev: %p, size: %ld\n",
-              it, it.next, it.prev, it.size)
-    it = it.next
+when false:
+  proc writeFreeList(a: MemRegion) =
+    var it = a.freeChunksList
+    c_fprintf(stdout, "freeChunksList: %p\n", it)
+    while it != nil:
+      c_fprintf(stdout, "it: %p, next: %p, prev: %p, size: %ld\n",
+                it, it.next, it.prev, it.size)
+      it = it.next
 
 const nimMaxHeap {.intdefine.} = 0
 

lib/system/gc.nim

@@ -155,14 +155,15 @@ template setColor(c, col) =
   else:
     c.refcount = c.refcount and not colorMask or col
 
-proc writeCell(msg: cstring, c: PCell) =
-  var kind = -1
-  var typName: cstring = "nil"
-  if c.typ != nil:
-    kind = ord(c.typ.kind)
-    when defined(nimTypeNames):
-      if not c.typ.name.isNil:
-        typName = c.typ.name
+when defined(logGC):
+  proc writeCell(msg: cstring, c: PCell) =
+    var kind = -1
+    var typName: cstring = "nil"
+    if c.typ != nil:
+      kind = ord(c.typ.kind)
+      when defined(nimTypeNames):
+        if not c.typ.name.isNil:
+          typName = c.typ.name
 
   when leakDetector:
     c_fprintf(stdout, "[GC] %s: %p %d %s rc=%ld from %s(%ld)\n",