Add option to export tracing events to ETW.

base/trace_event/trace_event_etw_export_win.cc

+// Copyright (c) 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/trace_event/trace_event_etw_export_win.h"
+
+#include "base/command_line.h"
+#include "base/logging.h"
+#include "base/memory/singleton.h"
+#include "base/strings/utf_string_conversions.h"
+#include "base/trace_event/trace_event.h"
+#include "base/trace_event/trace_event_impl.h"
+
+// The GetProcAddress technique is borrowed from
+// https://github.com/randomascii/main/tree/master/xperf/ETWProviders
+//
+// EVNTAPI is used in evntprov.h which is included by chrome_events_win.h.
+// We define EVNTAPI without the DECLSPEC_IMPORT specifier so that we can
+// implement these functions locally instead of using the import library, and
+// can therefore still run on Windows XP.
+#define EVNTAPI __stdcall
+// Include the event register/write/unregister macros compiled from the manifest
+// file. Note that this includes evntprov.h which requires a Vista+ Windows SDK.
+//
+// In SHARED_INTERMEDIATE_DIR.
+#include "base/trace_event/etw_manifest/chrome_events_win.h"  // NOLINT
+
+namespace {
+// Typedefs for use with GetProcAddress
+typedef ULONG(__stdcall* tEventRegister)(LPCGUID ProviderId,
+                                         PENABLECALLBACK EnableCallback,
+                                         PVOID CallbackContext,
+                                         PREGHANDLE RegHandle);
+typedef ULONG(__stdcall* tEventWrite)(REGHANDLE RegHandle,
+                                      PCEVENT_DESCRIPTOR EventDescriptor,
+                                      ULONG UserDataCount,
+                                      PEVENT_DATA_DESCRIPTOR UserData);
+typedef ULONG(__stdcall* tEventUnregister)(REGHANDLE RegHandle);
+
+tEventRegister EventRegisterProc = nullptr;
+tEventWrite EventWriteProc = nullptr;
+tEventUnregister EventUnregisterProc = nullptr;
+}  // namespace
+
+// Redirector function for EventRegister. Called by macros in
+// chrome_events_win.h

[Nico, 2015/04/14 02:25:09]

I can't see a file chrome_events_win.h, and I also don't really see macros in
this CL – what does this refer to?

[Georges Khalil, 2015/04/15 15:10:32]

chrome_events_win.h is generated from chrome_events_win.rc using
mc.exe and contains a bunch of macros to interact with ETW (mainly
un/registering and writing events).

Lines 28 to 74 are needed to avoid breaking Windows XP, as these
functions do not exist in XP. The comment right above details this.

+ULONG EVNTAPI EventRegister(LPCGUID ProviderId,
+                            PENABLECALLBACK EnableCallback,
+                            PVOID CallbackContext,
+                            PREGHANDLE RegHandle) {
+  if (EventRegisterProc)
+    return EventRegisterProc(ProviderId, EnableCallback, CallbackContext,
+                             RegHandle);
+  return 0;
+}
+
+// Redirector function for EventWrite. Called by macros in
+// chrome_events_win.h
+ULONG EVNTAPI EventWrite(REGHANDLE RegHandle,
+                         PCEVENT_DESCRIPTOR EventDescriptor,
+                         ULONG UserDataCount,
+                         PEVENT_DATA_DESCRIPTOR UserData) {
+  if (EventWriteProc)
+    return EventWriteProc(RegHandle, EventDescriptor, UserDataCount, UserData);
+  return 0;
+}
+
+// Redirector function for EventUnregister. Called by macros in
+// chrome_events_win.h
+ULONG EVNTAPI EventUnregister(REGHANDLE RegHandle) {
+  if (EventUnregisterProc)
+    return EventUnregisterProc(RegHandle);
+  return 0;
+}
+
+namespace base {
+namespace trace_event {
+
+TraceEventETWExport::TraceEventETWExport() : ETWExportEnabled_(false) {
+  // Find Advapi32.dll. This should always succeed.
+  HMODULE AdvapiDLL = ::LoadLibraryW(L"Advapi32.dll");
+  if (AdvapiDLL) {
+    // Try to find the ETW functions. This will fail on XP.
+    EventRegisterProc = reinterpret_cast<tEventRegister>(
+        ::GetProcAddress(AdvapiDLL, "EventRegister"));
+    EventWriteProc = reinterpret_cast<tEventWrite>(
+        ::GetProcAddress(AdvapiDLL, "EventWrite"));
+    EventUnregisterProc = reinterpret_cast<tEventUnregister>(
+        ::GetProcAddress(AdvapiDLL, "EventUnregister"));
+
+    // Register the ETW provider. If registration fails then the event logging
+    // calls will fail (on XP this call will do nothing).
+    EventRegisterChrome();
+  }
+}
+
+TraceEventETWExport::~TraceEventETWExport() {
+  EventUnregisterChrome();
+}
+
+// static
+TraceEventETWExport* TraceEventETWExport::GetInstance() {
+  return Singleton<TraceEventETWExport,
+                   StaticMemorySingletonTraits<TraceEventETWExport>>::get();
+}
+
+// static
+void TraceEventETWExport::EnableETWExport() {
+  GetInstance()->ETWExportEnabled_ = true;
+}
+
+// static
+void TraceEventETWExport::DisableETWExport() {
+  GetInstance()->ETWExportEnabled_ = false;
+}
+
+// static
+void TraceEventETWExport::AddEvent(
+    char phase,
+    const unsigned char* category_group_enabled,
+    const char* name,
+    unsigned long long id,
+    int num_args,
+    const char** arg_names,
+    const unsigned char* arg_types,
+    const unsigned long long* arg_values,
+    const scoped_refptr<ConvertableToTraceFormat>* convertable_values) {
+  // We bail early in case exporting is disabled or no consumer is listening.
+  if (!GetInstance()->ETWExportEnabled_ || !EventEnabledChromeEvent())
+    return;
+
+  std::string phase_string;
+  switch (phase) {
+    case TRACE_EVENT_PHASE_BEGIN:
+      phase_string = "Begin";
+      break;
+    case TRACE_EVENT_PHASE_END:
+      phase_string = "End";
+      break;
+    case TRACE_EVENT_PHASE_COMPLETE:
+      phase_string = "Complete";
+      break;
+    case TRACE_EVENT_PHASE_INSTANT:
+      phase_string = "Instant";
+      break;
+    case TRACE_EVENT_PHASE_ASYNC_BEGIN:
+      phase_string = "Async Begin";
+      break;
+    case TRACE_EVENT_PHASE_ASYNC_STEP_INTO:
+      phase_string = "Async Step Into";
+      break;
+    case TRACE_EVENT_PHASE_ASYNC_STEP_PAST:
+      phase_string = "Async Step Past";
+      break;
+    case TRACE_EVENT_PHASE_ASYNC_END:
+      phase_string = "Async End";
+      break;
+    case TRACE_EVENT_PHASE_NESTABLE_ASYNC_BEGIN:
+      phase_string = "Nestable Async Begin";
+      break;
+    case TRACE_EVENT_PHASE_NESTABLE_ASYNC_END:
+      phase_string = "Nestable Async End";
+      break;
+    case TRACE_EVENT_PHASE_NESTABLE_ASYNC_INSTANT:
+      phase_string = "Nestable Async Instant";
+      break;
+    case TRACE_EVENT_PHASE_FLOW_BEGIN:
+      phase_string = "Phase Flow Begin";
+      break;
+    case TRACE_EVENT_PHASE_FLOW_STEP:
+      phase_string = "Phase Flow Step";
+      break;
+    case TRACE_EVENT_PHASE_FLOW_END:
+      phase_string = "Phase Flow End";
+      break;
+    case TRACE_EVENT_PHASE_METADATA:
+      phase_string = "Phase Metadata";
+      break;
+    case TRACE_EVENT_PHASE_COUNTER:
+      phase_string = "Phase Counter";
+      break;
+    case TRACE_EVENT_PHASE_SAMPLE:
+      phase_string = "Phase Sample";
+      break;
+    case TRACE_EVENT_PHASE_CREATE_OBJECT:
+      phase_string = "Phase Create Object";
+      break;
+    case TRACE_EVENT_PHASE_SNAPSHOT_OBJECT:
+      phase_string = "Phase Snapshot Object";
+      break;
+    case TRACE_EVENT_PHASE_DELETE_OBJECT:
+      phase_string = "Phase Delete Object";
+      break;
+    default:
+      phase_string.push_back(phase);
+      break;
+  }
+
+  std::string arg_values_string[3];
+  for (int i = 0; i < num_args; i++) {
+    if (arg_types[i] == TRACE_VALUE_TYPE_CONVERTABLE) {
+      convertable_values[i]->AppendAsTraceFormat(arg_values_string + i);
+    } else {
+      TraceEvent::TraceValue trace_event;
+      trace_event.as_uint = arg_values[i];
+      TraceEvent::AppendValueAsJSON(arg_types[i], trace_event,
+                                    arg_values_string + i);
+    }
+  }
+
+  EventWriteChromeEvent(
+      name, phase_string.c_str(), num_args > 0 ? arg_names[0] : "",
+      arg_values_string[0].c_str(), num_args > 1 ? arg_names[1] : "",
+      arg_values_string[1].c_str(), num_args > 2 ? arg_names[2] : "",
+      arg_values_string[2].c_str());
+}
+
+// static
+void TraceEventETWExport::AddCustomEvent(const char* name,
+                                         char const* phase,
+                                         const char* arg_name_1,
+                                         const char* arg_value_1,
+                                         const char* arg_name_2,
+                                         const char* arg_value_2,
+                                         const char* arg_name_3,
+                                         const char* arg_value_3) {
+  if (!GetInstance()->ETWExportEnabled_ || !EventEnabledChromeEvent())
+    return;
+
+  EventWriteChromeEvent(name, phase, arg_name_1, arg_value_1, arg_name_2,
+                        arg_value_2, arg_name_3, arg_value_3);
+}
+
+void TraceEventETWExport::Resurrect() {
+  StaticMemorySingletonTraits<TraceEventETWExport>::Resurrect();
+}
+
+}  // namespace trace_event
+}  // namespace base