include/llvm/Support/TimeProfiler.h

   1 //===- llvm/Support/TimeProfiler.h - Hierarchical Time Profiler -*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_SUPPORT_TIME_PROFILER_H
  10 #define LLVM_SUPPORT_TIME_PROFILER_H
  11
  12 #include "llvm/Support/raw_ostream.h"
  13
  14 namespace llvm {
  15
  16 struct TimeTraceProfiler;
  17 extern TimeTraceProfiler *TimeTraceProfilerInstance;
  18
  19 /// Initialize the time trace profiler.
  20 /// This sets up the global \p TimeTraceProfilerInstance
  21 /// variable to be the profiler instance.
  22 void timeTraceProfilerInitialize(unsigned TimeTraceGranularity);
  23
  24 /// Cleanup the time trace profiler, if it was initialized.
  25 void timeTraceProfilerCleanup();
  26
  27 /// Is the time trace profiler enabled, i.e. initialized?
  28 inline bool timeTraceProfilerEnabled() {
  29   return TimeTraceProfilerInstance != nullptr;
  30 }
  31
  32 /// Write profiling data to output file.
  33 /// Data produced is JSON, in Chrome "Trace Event" format, see
  34 /// https://docs.google.com/document/d/1CvAClvFfyA5R-PhYUmn5OOQtYMH4h6I0nSsKchNAySU/preview
  35 void timeTraceProfilerWrite(raw_pwrite_stream &OS);
  36
  37 /// Manually begin a time section, with the given \p Name and \p Detail.
  38 /// Profiler copies the string data, so the pointers can be given into
  39 /// temporaries. Time sections can be hierarchical; every Begin must have a
  40 /// matching End pair but they can nest.
  41 void timeTraceProfilerBegin(StringRef Name, StringRef Detail);
  42 void timeTraceProfilerBegin(StringRef Name,
  43                             llvm::function_ref<std::string()> Detail);
  44
  45 /// Manually end the last time section.
  46 void timeTraceProfilerEnd();
  47
  48 /// The TimeTraceScope is a helper class to call the begin and end functions
  49 /// of the time trace profiler.  When the object is constructed, it begins
  50 /// the section; and when it is destroyed, it stops it. If the time profiler
  51 /// is not initialized, the overhead is a single branch.
  52 struct TimeTraceScope {
  53
  54   TimeTraceScope() = delete;
  55   TimeTraceScope(const TimeTraceScope &) = delete;
  56   TimeTraceScope &operator=(const TimeTraceScope &) = delete;
  57   TimeTraceScope(TimeTraceScope &&) = delete;
  58   TimeTraceScope &operator=(TimeTraceScope &&) = delete;
  59
  60   TimeTraceScope(StringRef Name, StringRef Detail) {
  61     if (TimeTraceProfilerInstance != nullptr)
  62       timeTraceProfilerBegin(Name, Detail);
  63   }
  64   TimeTraceScope(StringRef Name, llvm::function_ref<std::string()> Detail) {
  65     if (TimeTraceProfilerInstance != nullptr)
  66       timeTraceProfilerBegin(Name, Detail);
  67   }
  68   ~TimeTraceScope() {
  69     if (TimeTraceProfilerInstance != nullptr)
  70       timeTraceProfilerEnd();
  71   }
  72 };
  73
  74 } // end namespace llvm
  75
  76 #endif