thread var emulation should work again

compiler/cgen.nim

@@ -792,11 +792,11 @@ proc getFileHeader(cfilenoext: string): PRope =
 proc genMainProc(m: BModule) = 
   const 
     CommonMainBody = 
-        "#initStackBottom();$n" &
+        "$1" &
         "\tnim__datInit();$n" &
         "\tsystemInit();$n" & 
-        "$1" & 
+        "$2" & 
-        "$2"
+        "$3"
     PosixNimMain = 
         "int cmdCount;$n" & 
         "char** cmdLine;$n" & 
@@ -845,8 +845,11 @@ proc genMainProc(m: BModule) =
     nimMain = PosixNimMain
     otherMain = PosixCMain
   if gBreakpoints != nil: discard cgsym(m, "dbgRegisterBreakpoint")
+  
+  let initStackBottomCall = if emulatedThreadVars(): "".toRope
+                            else: ropecg(m, "\t#initStackBottom();$n")
   inc(m.labels)
-  appcg(m, m.s[cfsProcs], nimMain, [
+  appcg(m, m.s[cfsProcs], nimMain, [initStackBottomCall,
         gBreakpoints, mainModInit, toRope(m.labels)])
   if optNoMain notin gGlobalOptions:
     appcg(m, m.s[cfsProcs], otherMain, [])

lib/system/gc.nim

@@ -632,6 +632,7 @@ else:
   const stackIncreases = false
 
 when not defined(useNimRtl):
+  {.push stack_trace: off.}
   proc setStackBottom(theStackBottom: pointer) =
     #c_fprintf(c_stdout, "stack bottom: %p;\n", theStackBottom)
     # the first init must be the one that defines the stack bottom:
@@ -644,6 +645,7 @@ when not defined(useNimRtl):
         gch.stackBottom = cast[pointer](min(a, b))
       else:
         gch.stackBottom = cast[pointer](max(a, b))
+  {.pop.}
 
 proc stackSize(): int {.noinline.} =
   var stackTop {.volatile.}: pointer

tests/gc/gcleak4.nim

@@ -10,8 +10,10 @@ type
   PLiteral = ref TLiteral
   TLiteral = object of TExpr
     x: int
+    op1: string
   TPlusExpr = object of TExpr
     a, b: ref TExpr
+    op2: string
     
 method eval(e: ref TExpr): int =
   # override this base method
@@ -27,16 +29,21 @@ proc newLit(x: int): ref TLiteral =
   new(result)
   {.watchpoint: result.}
   result.x = x
+  result.op1 = $getOccupiedMem()
   
 proc newPlus(a, b: ref TExpr): ref TPlusExpr =
   new(result)
   {.watchpoint: result.}
   result.a = a
   result.b = b
+  result.op2 = $getOccupiedMem()
 
 for i in 0..100_000:
-  if eval(newPlus(newPlus(newLit(1), newLit(2)), newLit(4))) != 7:
+  var s: array[0..11, ref TExpr]
+  for j in 0..high(s):
+    s[j] = newPlus(newPlus(newLit(j), newLit(2)), newLit(4))
+    if eval(s[j]) != j+6:
       quit "error: wrong result"
-  if getOccupiedMem() > 3000_000: quit("still a leak!")
+  if getOccupiedMem() > 500_000: quit("still a leak!")
 
 echo "no leak: ", getOccupiedMem()

todo.txt

@@ -2,8 +2,6 @@ version 0.9.0
 =============
 
 Debug GC session:
-- bug: stress testing basic method example (eval example) 
-  without ``-d:release`` leaks memory?
 - test sequence of closures; especially that the GC does not leak for those!
 
 New pragmas:
@@ -14,6 +12,7 @@ New pragmas:
 - make templates hygienic by default: try to gensym() everything in the 'block'
   of a template; find a better solution for gensym instead of `*ident`
 - ``=`` should be overloadable; requires specialization for ``=``
+- optimize genericAssign in the code generator
 - fix remaining closure bugs:
   - make toplevel but in a scope vars local; make procs there inner procs
   - fix evals.nim with closures