fixes #10148 (#10149)

* fixes #10148
* fix a typo

compiler/cgen.nim

@@ -1103,9 +1103,8 @@ proc genMainProc(m: BModule) =
       "}$N$N" &
       "void PreMain(void) {$N" &
       "\tvoid (*volatile inner)(void);$N" &
-      "$1" &
       "\tinner = PreMainInner;$N" &
-      "$4$5" &
+      "$1" &
       "\t(*inner)();$N" &
       "}$N$N"
 
@@ -1222,12 +1221,7 @@ proc genMainProc(m: BModule) =
     else: ropecg(m, "\t#initStackBottomWith((void *)&inner);$N")
   inc(m.labels)
   appcg(m, m.s[cfsProcs], PreMainBody, [
-    m.g.mainDatInit, m.g.breakpoints, m.g.otherModsInit,
-     if emulatedThreadVars(m.config) and m.config.target.targetOS != osStandalone:
-       ropecg(m, "\t#initThreadVarsEmulation();$N")
-     else:
-       "".rope,
-     initStackBottomCall])
+    m.g.mainDatInit, m.g.breakpoints, m.g.otherModsInit])
 
   appcg(m, m.s[cfsProcs], nimMain,
         [m.g.mainModInit, initStackBottomCall, rope(m.labels)])
@@ -1256,21 +1250,32 @@ proc getInitName(m: PSym): Rope =
 
 proc getDatInitName(m: PSym): Rope = getSomeInitName(m, "DatInit000")
 
+
 proc registerModuleToMain(g: BModuleList; m: BModule) =
+  if m.s[cfsDatInitProc].len > 0:
+    let datInit = m.module.getDatInitName
+    addf(g.mainModProcs, "N_LIB_PRIVATE N_NIMCALL(void, $1)(void);$N", [datInit])
+    addf(g.mainDatInit, "\t$1();$N", [datInit])
+
+  # Initialization of TLS and GC should be done in between
+  # systemDatInit and systemInit calls if any
+  if sfSystemModule in m.module.flags:
+    if emulatedThreadVars(m.config) and m.config.target.targetOS != osStandalone:
+      add(g.mainDatInit, ropecg(m, "\t#initThreadVarsEmulation();$N"))
+    if m.config.target.targetOS != osStandalone and m.config.selectedGC != gcNone:
+      add(g.mainDatInit, ropecg(m, "\t#initStackBottomWith((void *)&inner);$N"))
+
   if m.s[cfsInitProc].len > 0:
     let init = m.module.getInitName
     addf(g.mainModProcs, "N_LIB_PRIVATE N_NIMCALL(void, $1)(void);$N", [init])
     let initCall = "\t$1();$N" % [init]
     if sfMainModule in m.module.flags:
       add(g.mainModInit, initCall)
+    elif sfSystemModule in m.module.flags:
+      add(g.mainDatInit, initCall) # systemInit must called right after systemDatInit if any
     else:
       add(g.otherModsInit, initCall)
 
-  if m.s[cfsDatInitProc].len > 0:
-    let datInit = m.module.getDatInitName
-    addf(g.mainModProcs, "N_LIB_PRIVATE N_NIMCALL(void, $1)(void);$N", [datInit])
-    addf(g.mainDatInit, "\t$1();$N", [datInit])
-
 proc genDatInitCode(m: BModule) =
   ## this function is called in cgenWriteModules after all modules are closed,
   ## it means raising dependency on the symbols is too late as it will not propogate

tests/cpp/t10148.nim

@@ -0,0 +1,29 @@
+discard """
+  output: '''Expected successful exit'''
+  joinable: false
+"""
+
+import os
+
+proc another_proc: string =
+  ## trigger many GC allocations
+  var x = @[""]
+  for i in 0..100:
+   x.add $i
+  result = "not_existent_path"
+
+proc findlib2: string =
+  let path = getEnv("MYLIB2_DOES_NOT_EXIST_PATH")
+  let another_path = another_proc()
+  GC_fullCollect()
+
+  if path.len > 0 and dirExists(path):
+    path / "alib_does_not_matter.dll"
+  elif fileExists(another_path):
+    another_path
+  else:
+    quit("Expected successful exit", 0)
+
+proc imported_func*(a: cint): cstring {.importc, dynlib: findlib2().}
+
+echo imported_func(0)