fixes #17085 [backport:1.2] (#17101)

compiler/ccgstmts.nim

@@ -25,10 +25,10 @@ proc getTraverseProc(p: BProc, v: PSym): Rope =
 
 proc registerTraverseProc(p: BProc, v: PSym, traverseProc: Rope) =
   if sfThread in v.flags:
-    appcg(p.module, p.module.initProc.procSec(cpsInit),
+    appcg(p.module, p.module.preInitProc.procSec(cpsInit),
       "$n\t#nimRegisterThreadLocalMarker($1);$n$n", [traverseProc])
   else:
-    appcg(p.module, p.module.initProc.procSec(cpsInit),
+    appcg(p.module, p.module.preInitProc.procSec(cpsInit),
       "$n\t#nimRegisterGlobalMarker($1);$n$n", [traverseProc])
 
 proc isAssignedImmediately(conf: ConfigRef; n: PNode): bool {.inline.} =

compiler/cgen.nim

@@ -1654,7 +1654,7 @@ proc genInitCode(m: BModule) =
     writeSection(preInitProc, cpsLocals)
     writeSection(preInitProc, cpsInit, m.hcrOn)
     writeSection(preInitProc, cpsStmts)
-    prc.addf("}$N", [])
+    prc.addf("}/* preInitProc end */$N", [])
     when false:
       m.initProc.blocks[0].sections[cpsLocals].add m.preInitProc.s(cpsLocals)
       m.initProc.blocks[0].sections[cpsInit].prepend m.preInitProc.s(cpsInit)

testament/categories.nim

@@ -174,6 +174,7 @@ proc gcTests(r: var TResults, cat: Category, options: string) =
 
   test "stackrefleak"
   test "cyclecollector"
+  test "trace_globals"
 
 proc longGCTests(r: var TResults, cat: Category, options: string) =
   when defined(windows):

tests/gc/trace_globals.nim

@@ -0,0 +1,22 @@
+discard """
+  output: '''10000000
+10000000
+10000000'''
+"""
+
+# bug #17085
+
+proc init(): string =
+  for a in 0..<10000000:
+    result.add 'c'
+
+proc f() =
+  var a {.global.} = init()
+  var b {.global.} = init()
+  var c {.global.} = init()
+
+  echo a.len
+  echo b.len
+  echo c.len
+
+f()