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                                  StringRef ProcName);
24 
25 /// Cleanup the time trace profiler, if it was initialized.
26 void timeTraceProfilerCleanup();
27 
28 /// Is the time trace profiler enabled, i.e. initialized?
29 inline bool timeTraceProfilerEnabled() {
30   return TimeTraceProfilerInstance != nullptr;
31 }
32 
33 /// Write profiling data to output file.
34 /// Data produced is JSON, in Chrome "Trace Event" format, see
35 /// https://docs.google.com/document/d/1CvAClvFfyA5R-PhYUmn5OOQtYMH4h6I0nSsKchNAySU/preview
36 void timeTraceProfilerWrite(raw_pwrite_stream &OS);
37 
38 /// Manually begin a time section, with the given \p Name and \p Detail.
39 /// Profiler copies the string data, so the pointers can be given into
40 /// temporaries. Time sections can be hierarchical; every Begin must have a
41 /// matching End pair but they can nest.
42 void timeTraceProfilerBegin(StringRef Name, StringRef Detail);
43 void timeTraceProfilerBegin(StringRef Name,
44                             llvm::function_ref<std::string()> Detail);
45 
46 /// Manually end the last time section.
47 void timeTraceProfilerEnd();
48 
49 /// The TimeTraceScope is a helper class to call the begin and end functions
50 /// of the time trace profiler.  When the object is constructed, it begins
51 /// the section; and when it is destroyed, it stops it. If the time profiler
52 /// is not initialized, the overhead is a single branch.
53 struct TimeTraceScope {
54 
55   TimeTraceScope() = delete;
56   TimeTraceScope(const TimeTraceScope &) = delete;
57   TimeTraceScope &operator=(const TimeTraceScope &) = delete;
58   TimeTraceScope(TimeTraceScope &&) = delete;
59   TimeTraceScope &operator=(TimeTraceScope &&) = delete;
60 
61   TimeTraceScope(StringRef Name) {
62     if (TimeTraceProfilerInstance != nullptr)
63       timeTraceProfilerBegin(Name, StringRef(""));
64   }
65   TimeTraceScope(StringRef Name, StringRef Detail) {
66     if (TimeTraceProfilerInstance != nullptr)
67       timeTraceProfilerBegin(Name, Detail);
68   }
69   TimeTraceScope(StringRef Name, llvm::function_ref<std::string()> Detail) {
70     if (TimeTraceProfilerInstance != nullptr)
71       timeTraceProfilerBegin(Name, Detail);
72   }
73   ~TimeTraceScope() {
74     if (TimeTraceProfilerInstance != nullptr)
75       timeTraceProfilerEnd();
76   }
77 };
78 
79 } // end namespace llvm
80 
81 #endif
82