added another system.getStackTrace

lib/system.nim

@@ -190,6 +190,7 @@ type
     msg* {.exportc: "message".}: string ## the exception's message. Not
                                         ## providing an exception message 
                                         ## is bad style.
+    trace: string
 
   EAsynch* = object of E_Base ## Abstract exception class for
                               ## *asynchronous exceptions* (interrupts).
@@ -1900,6 +1901,10 @@ when not defined(EcmaScript) and not defined(NimrodVM):
   when hostOS != "standalone":
     proc getStackTrace*(): string
       ## gets the current stack trace. This is only works for debug builds.
+
+    proc getStackTrace*(e: ref E_Base): string
+      ## gets the stack trace associated with `e`, which is the stack that
+      ## lead to the ``raise`` statement. This is only works for debug builds.
       
   {.push stack_trace: off.}
   when hostOS == "standalone":

lib/system/excpt.nim

@@ -194,6 +194,9 @@ proc quitOrDebug() {.inline.} =
 
 proc raiseException(e: ref E_Base, ename: CString) {.compilerRtl.} =
   e.name = ename
+  when hasSomeStackTrace:
+    e.trace = ""
+    rawWriteStackTrace(e.trace)
   if localRaiseHook != nil:
     if not localRaiseHook(e): return
   if globalRaiseHook != nil:
@@ -253,6 +256,12 @@ proc getStackTrace(): string =
   else:
     result = "No stack traceback available\n"
 
+proc getStackTrace(e: ref E_Base): string =
+  if not isNil(e) and not isNil(e.trace):
+    result = e.trace
+  else:
+    result = ""
+
 when defined(endb):
   var
     dbgAborting: bool # whether the debugger wants to abort