1 files changed, 126 insertions, 0 deletions
diff --git a/tool/lib/tracepointchecker.rb b/tool/lib/tracepointchecker.rb
new file mode 100644
index 0000000000..47822ecef5
--- /dev/null
+++ b/tool/lib/tracepointchecker.rb
@@ -0,0 +1,126 @@
+# frozen_string_literal: true
+module TracePointChecker
+  STATE = {
+    count: 0,
+    running: false,
+  }
+
+  module ZombieTraceHunter
+    def tracepoint_capture_stat_get
+      TracePoint.stat.map{|k, (activated, deleted)|
+        deleted = 0 unless @tracepoint_captured_singlethread
+        [k, activated, deleted]
+      }
+    end
+
+    def before_setup
+      @tracepoint_captured_singlethread = (Thread.list.size == 1)
+      @tracepoint_captured_stat = tracepoint_capture_stat_get()
+      super
+    end
+
+    def after_teardown
+      super
+
+      # detect zombie traces.
+      assert_equal(
+        @tracepoint_captured_stat,
+        tracepoint_capture_stat_get(),
+        "The number of active/deleted trace events was changed"
+      )
+      # puts "TracePoint - deleted: #{deleted}" if deleted > 0
+
+      TracePointChecker.check if STATE[:running]
+    end
+  end
+
+  MAIN_THREAD = Thread.current
+  TRACES = []
+
+  def self.prefix event
+    case event
+    when :call, :return
+      :n
+    when :c_call, :c_return
+      :c
+    when :b_call, :b_return
+      :b
+    end
+  end
+
+  def self.clear_call_stack
+    Thread.current[:call_stack] = []
+  end
+
+  def self.call_stack
+    stack = Thread.current[:call_stack]
+    stack = clear_call_stack unless stack
+    stack
+  end
+
+  def self.verbose_out label, method
+    puts label => call_stack, :count => STATE[:count], :method => method
+  end
+
+  def self.method_label tp
+    "#{prefix(tp.event)}##{tp.method_id}"
+  end
+
+  def self.start verbose: false, stop_at_failure: false
+    call_events = %i(a_call)
+    return_events = %i(a_return)
+    clear_call_stack
+
+    STATE[:running] = true
+
+    TRACES << TracePoint.new(*call_events){|tp|
+      next if Thread.current != MAIN_THREAD
+
+      method = method_label(tp)
+      call_stack.push method
+      STATE[:count] += 1
+
+      verbose_out :psuh, method if verbose
+    }
+
+    TRACES << TracePoint.new(*return_events){|tp|
+      next if Thread.current != MAIN_THREAD
+      STATE[:count] += 1
+
+      method = "#{prefix(tp.event)}##{tp.method_id}"
+      verbose_out :pop1, method if verbose
+
+      stored_method = call_stack.pop
+      next if stored_method.nil?
+
+      verbose_out :pop2, method if verbose
+
+      if stored_method != method
+        stop if stop_at_failure
+        RubyVM::SDR() if defined? RubyVM::SDR()
+        call_stack.clear
+        raise "#{stored_method} is expected, but #{method} (count: #{STATE[:count]})"
+      end
+    }
+
+    TRACES.each{|trace| trace.enable}
+  end
+
+  def self.stop
+    STATE[:running] = true
+    TRACES.each{|trace| trace.disable}
+    TRACES.clear
+  end
+
+  def self.check
+    TRACES.each{|trace|
+      raise "trace #{trace} should not be deactivated" unless trace.enabled?
+    }
+  end
+end if defined?(TracePoint.stat)
+
+class ::Test::Unit::TestCase
+  include TracePointChecker::ZombieTraceHunter
+end if defined?(TracePointChecker)
+
+# TracePointChecker.start verbose: false