mozglue/misc/AutoProfilerLabel.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_AutoProfilerLabel_h
   8 #define mozilla_AutoProfilerLabel_h
   9
  10 #include "mozilla/Attributes.h"
  11
  12 #include "mozilla/Types.h"
  13 #include <tuple>
  14
  15 // The Gecko Profiler defines AutoProfilerLabel, an RAII class for
  16 // pushing/popping frames to/from the ProfilingStack.
  17 //
  18 // This file defines a class of the same name that does much the same thing,
  19 // but which can be used in (and only in) mozglue. A different class is
  20 // necessary because mozglue cannot directly access sProfilingStack.
  21 //
  22 // Note that this class is slightly slower than the other AutoProfilerLabel,
  23 // and it lacks the macro wrappers. It also is effectively hardwired to use
  24 // JS::ProfilingCategory::OTHER as the category pair, because that's what
  25 // the callbacks provided by the profiler use. (Specifying the categories in
  26 // this file would require #including ProfilingCategory.h in mozglue, which we
  27 // don't want to do.)
  28
  29 namespace mozilla {
  30
  31 // Enter should return a pointer that will be given to Exit.
  32 typedef void* (*ProfilerLabelEnter)(const char* aLabel,
  33                                     const char* aDynamicString, void* aSp);
  34 typedef void (*ProfilerLabelExit)(void* EntryContext);
  35
  36 // Register callbacks that do the entry/exit work involving sProfilingStack.
  37 MFBT_API void RegisterProfilerLabelEnterExit(ProfilerLabelEnter aEnter,
  38                                              ProfilerLabelExit aExit);
  39
  40 // This #ifdef prevents this AutoProfilerLabel from being defined in libxul,
  41 // which would conflict with the one in the profiler.
  42 #ifdef IMPL_MFBT
  43
  44 class MOZ_RAII AutoProfilerLabel {
  45  public:
  46   AutoProfilerLabel(const char* aLabel, const char* aDynamicString);
  47   ~AutoProfilerLabel();
  48
  49  private:
  50   void* mEntryContext;
  51   // Number of RegisterProfilerLabelEnterExit calls, to avoid giving an entry
  52   // context from one generation to the next.
  53   uint32_t mGeneration;
  54 };
  55
  56 using ProfilerLabel = std::tuple<void*, uint32_t>;
  57
  58 bool IsProfilerPresent();
  59 ProfilerLabel ProfilerLabelBegin(const char* aLabelName,
  60                                  const char* aDynamicString, void* aSp);
  61 void ProfilerLabelEnd(const ProfilerLabel& aLabel);
  62
  63 inline bool IsValidProfilerLabel(const ProfilerLabel& aLabel) {
  64   return !!std::get<0>(aLabel);
  65 }
  66
  67 #endif
  68
  69 }  // namespace mozilla
  70
  71 #endif  // mozilla_AutoProfilerLabel_h