1// Copyright 2014 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "base/debug/task_annotator.h"
6
7#include "base/debug/alias.h"
8#include "base/pending_task.h"
9#include "base/trace_event/trace_event.h"
10#include "base/tracked_objects.h"
11
12namespace base {
13namespace debug {
14
15TaskAnnotator::TaskAnnotator() {
16}
17
18TaskAnnotator::~TaskAnnotator() {
19}
20
21void TaskAnnotator::DidQueueTask(const char* queue_function,
22                                 const PendingTask& pending_task) {
23  TRACE_EVENT_WITH_FLOW0(TRACE_DISABLED_BY_DEFAULT("toplevel.flow"),
24                          queue_function,
25                          TRACE_ID_MANGLE(GetTaskTraceID(pending_task)),
26                          TRACE_EVENT_FLAG_FLOW_OUT);
27}
28
29void TaskAnnotator::RunTask(const char* queue_function,
30                            const PendingTask& pending_task) {
31  tracked_objects::TaskStopwatch stopwatch;
32  stopwatch.Start();
33  tracked_objects::Duration queue_duration =
34      stopwatch.StartTime() - pending_task.EffectiveTimePosted();
35
36  TRACE_EVENT_WITH_FLOW1(TRACE_DISABLED_BY_DEFAULT("toplevel.flow"),
37                          queue_function,
38                          TRACE_ID_MANGLE(GetTaskTraceID(pending_task)),
39                          TRACE_EVENT_FLAG_FLOW_IN,
40                          "queue_duration",
41                          queue_duration.InMilliseconds());
42
43  // Before running the task, store the program counter where it was posted
44  // and deliberately alias it to ensure it is on the stack if the task
45  // crashes. Be careful not to assume that the variable itself will have the
46  // expected value when displayed by the optimizer in an optimized build.
47  // Look at a memory dump of the stack.
48  const void* program_counter = pending_task.posted_from.program_counter();
49  debug::Alias(&program_counter);
50
51  pending_task.task.Run();
52
53  stopwatch.Stop();
54  tracked_objects::ThreadData::TallyRunOnNamedThreadIfTracking(
55      pending_task, stopwatch);
56}
57
58uint64_t TaskAnnotator::GetTaskTraceID(const PendingTask& task) const {
59  return (static_cast<uint64_t>(task.sequence_num) << 32) |
60         ((static_cast<uint64_t>(reinterpret_cast<intptr_t>(this)) << 32) >>
61          32);
62}
63
64}  // namespace debug
65}  // namespace base
66