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 #include "mozilla/Tuple.h"
  12 #include "mozilla/Types.h"
  13
  14 // The Gecko Profiler defines AutoProfilerLabel, an RAII class for
  15 // pushing/popping frames to/from the ProfilingStack.
  16 //
  17 // This file defines a class of the same name that does much the same thing,
  18 // but which can be used in (and only in) mozglue. A different class is
  19 // necessary because mozglue cannot directly access sProfilingStack.
  20 //
  21 // Note that this class is slightly slower than the other AutoProfilerLabel,
  22 // and it lacks the macro wrappers. It also is effectively hardwired to use
  23 // JS::ProfilingCategory::OTHER as the category pair, because that's what
  24 // the callbacks provided by the profiler use. (Specifying the categories in
  25 // this file would require #including ProfilingCategory.h in mozglue, which we
  26 // don't want to do.)
  27
  28 namespace mozilla {
  29
  30 // Enter should return a pointer that will be given to Exit.
  31 typedef void* (*ProfilerLabelEnter)(const char* aLabel,
  32                                     const char* aDynamicString, void* aSp);
  33 typedef void (*ProfilerLabelExit)(void* EntryContext);
  34
  35 // Register callbacks that do the entry/exit work involving sProfilingStack.
  36 MFBT_API void RegisterProfilerLabelEnterExit(ProfilerLabelEnter aEnter,
  37                                              ProfilerLabelExit aExit);
  38
  39 // This #ifdef prevents this AutoProfilerLabel from being defined in libxul,
  40 // which would conflict with the one in the profiler.
  41 #ifdef IMPL_MFBT
  42
  43 class MOZ_RAII AutoProfilerLabel {
  44  public:
  45   AutoProfilerLabel(const char* aLabel, const char* aDynamicString);
  46   ~AutoProfilerLabel();
  47
  48  private:
  49   void* mEntryContext;
  50   // Number of RegisterProfilerLabelEnterExit calls, to avoid giving an entry
  51   // context from one generation to the next.
  52   uint32_t mGeneration;
  53 };
  54
  55 using ProfilerLabel = Tuple<void*, uint32_t>;
  56
  57 bool IsProfilerPresent();
  58 ProfilerLabel ProfilerLabelBegin(const char* aLabelName,
  59                                  const char* aDynamicString, void* aSp);
  60 void ProfilerLabelEnd(const ProfilerLabel& aLabel);
  61
  62 inline bool IsValidProfilerLabel(const ProfilerLabel& aLabel) {
  63   return !!Get<0>(aLabel);
  64 }
  65
  66 #endif
  67
  68 }  // namespace mozilla
  69
  70 #endif  // mozilla_AutoProfilerLabel_h