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/Error.h"
13 #include "llvm/Support/raw_ostream.h"
14
15 namespace llvm {
16
17 struct TimeTraceProfiler;
18 TimeTraceProfiler *getTimeTraceProfilerInstance();
19
20 /// Initialize the time trace profiler.
21 /// This sets up the global \p TimeTraceProfilerInstance
22 /// variable to be the profiler instance.
23 void timeTraceProfilerInitialize(unsigned TimeTraceGranularity,
24 StringRef ProcName);
25
26 /// Cleanup the time trace profiler, if it was initialized.
27 void timeTraceProfilerCleanup();
28
29 /// Finish a time trace profiler running on a worker thread.
30 void timeTraceProfilerFinishThread();
31
32 /// Is the time trace profiler enabled, i.e. initialized?
timeTraceProfilerEnabled()33 inline bool timeTraceProfilerEnabled() {
34 return getTimeTraceProfilerInstance() != nullptr;
35 }
36
37 /// Write profiling data to output stream.
38 /// Data produced is JSON, in Chrome "Trace Event" format, see
39 /// https://docs.google.com/document/d/1CvAClvFfyA5R-PhYUmn5OOQtYMH4h6I0nSsKchNAySU/preview
40 void timeTraceProfilerWrite(raw_pwrite_stream &OS);
41
42 /// Write profiling data to a file.
43 /// The function will write to \p PreferredFileName if provided, if not
44 /// then will write to \p FallbackFileName appending .time-trace.
45 /// Returns a StringError indicating a failure if the function is
46 /// unable to open the file for writing.
47 Error timeTraceProfilerWrite(StringRef PreferredFileName,
48 StringRef FallbackFileName);
49
50 /// Manually begin a time section, with the given \p Name and \p Detail.
51 /// Profiler copies the string data, so the pointers can be given into
52 /// temporaries. Time sections can be hierarchical; every Begin must have a
53 /// matching End pair but they can nest.
54 void timeTraceProfilerBegin(StringRef Name, StringRef Detail);
55 void timeTraceProfilerBegin(StringRef Name,
56 llvm::function_ref<std::string()> Detail);
57
58 /// Manually end the last time section.
59 void timeTraceProfilerEnd();
60
61 /// The TimeTraceScope is a helper class to call the begin and end functions
62 /// of the time trace profiler. When the object is constructed, it begins
63 /// the section; and when it is destroyed, it stops it. If the time profiler
64 /// is not initialized, the overhead is a single branch.
65 struct TimeTraceScope {
66
67 TimeTraceScope() = delete;
68 TimeTraceScope(const TimeTraceScope &) = delete;
69 TimeTraceScope &operator=(const TimeTraceScope &) = delete;
70 TimeTraceScope(TimeTraceScope &&) = delete;
71 TimeTraceScope &operator=(TimeTraceScope &&) = delete;
72
TimeTraceScopeTimeTraceScope73 TimeTraceScope(StringRef Name) {
74 if (getTimeTraceProfilerInstance() != nullptr)
75 timeTraceProfilerBegin(Name, StringRef(""));
76 }
TimeTraceScopeTimeTraceScope77 TimeTraceScope(StringRef Name, StringRef Detail) {
78 if (getTimeTraceProfilerInstance() != nullptr)
79 timeTraceProfilerBegin(Name, Detail);
80 }
TimeTraceScopeTimeTraceScope81 TimeTraceScope(StringRef Name, llvm::function_ref<std::string()> Detail) {
82 if (getTimeTraceProfilerInstance() != nullptr)
83 timeTraceProfilerBegin(Name, Detail);
84 }
~TimeTraceScopeTimeTraceScope85 ~TimeTraceScope() {
86 if (getTimeTraceProfilerInstance() != nullptr)
87 timeTraceProfilerEnd();
88 }
89 };
90
91 } // end namespace llvm
92
93 #endif
94