Added option -Yheartbeat

… which shows snapshot of the callstack of tracked operations at fixed intervals.

1 files changed, 42 insertions, 1 deletions

diff --git a/src/dotty/tools/dotc/util/Stats.scala b/src/dotty/tools/dotc/util/Stats.scala
index 68884fdbc..3aa6eb9b9 100644
--- a/src/dotty/tools/dotc/util/Stats.scala
+++ b/src/dotty/tools/dotc/util/Stats.scala
@@ -1,7 +1,48 @@
-package dotty.tools.dotc.util
+package dotty.tools.dotc
+package util
+
+import core.Contexts._
 
 object Stats {
 
   final val enabled = true
 
+  /** The period in ms in which stack snapshots are displayed */
+  final val HeartBeatPeriod = 250
+
+  @volatile private var stack: List[String] = Nil
+
+  def track[T](fn: String)(op: => T) = {
+    stack = fn :: stack
+    try op
+    finally stack = stack.tail
+  }
+
+  class HeartBeat extends Thread() {
+    @volatile private[Stats] var continue = true
+
+    private def printStack(stack: List[String]): Unit = stack match {
+      case str :: rest =>
+        printStack(rest)
+        print(s"-> $str ")
+      case Nil =>
+        println()
+        print("|")
+    }
+
+    override final def run() {
+      Thread.sleep(HeartBeatPeriod)
+      printStack(stack)
+      if (continue) run()
+    }
+  }
+
+  def monitorHeartBeat[T](op: => T)(implicit ctx: Context) = {
+    if (ctx.settings.Yheartbeat.value) {
+      var hb = new HeartBeat()
+      hb.start()
+      try op
+      finally hb.continue = false
+    } else op
+  }
 }
\ No newline at end of file