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_TIMEPROFILER_H 10 #define LLVM_SUPPORT_TIMEPROFILER_H 11 12 #include "llvm/Support/Error.h" 13 #include "llvm/ADT/STLFunctionalExtras.h" 14 15 namespace llvm { 16 17 class raw_pwrite_stream; 18 19 struct TimeTraceProfiler; 20 TimeTraceProfiler *getTimeTraceProfilerInstance(); 21 22 /// Initialize the time trace profiler. 23 /// This sets up the global \p TimeTraceProfilerInstance 24 /// variable to be the profiler instance. 25 void timeTraceProfilerInitialize(unsigned TimeTraceGranularity, 26 StringRef ProcName); 27 28 /// Cleanup the time trace profiler, if it was initialized. 29 void timeTraceProfilerCleanup(); 30 31 /// Finish a time trace profiler running on a worker thread. 32 void timeTraceProfilerFinishThread(); 33 34 /// Is the time trace profiler enabled, i.e. initialized? 35 inline bool timeTraceProfilerEnabled() { 36 return getTimeTraceProfilerInstance() != nullptr; 37 } 38 39 /// Write profiling data to output stream. 40 /// Data produced is JSON, in Chrome "Trace Event" format, see 41 /// https://docs.google.com/document/d/1CvAClvFfyA5R-PhYUmn5OOQtYMH4h6I0nSsKchNAySU/preview 42 void timeTraceProfilerWrite(raw_pwrite_stream &OS); 43 44 /// Write profiling data to a file. 45 /// The function will write to \p PreferredFileName if provided, if not 46 /// then will write to \p FallbackFileName appending .time-trace. 47 /// Returns a StringError indicating a failure if the function is 48 /// unable to open the file for writing. 49 Error timeTraceProfilerWrite(StringRef PreferredFileName, 50 StringRef FallbackFileName); 51 52 /// Manually begin a time section, with the given \p Name and \p Detail. 53 /// Profiler copies the string data, so the pointers can be given into 54 /// temporaries. Time sections can be hierarchical; every Begin must have a 55 /// matching End pair but they can nest. 56 void timeTraceProfilerBegin(StringRef Name, StringRef Detail); 57 void timeTraceProfilerBegin(StringRef Name, 58 llvm::function_ref<std::string()> Detail); 59 60 /// Manually end the last time section. 61 void timeTraceProfilerEnd(); 62 63 /// The TimeTraceScope is a helper class to call the begin and end functions 64 /// of the time trace profiler. When the object is constructed, it begins 65 /// the section; and when it is destroyed, it stops it. If the time profiler 66 /// is not initialized, the overhead is a single branch. 67 struct TimeTraceScope { 68 69 TimeTraceScope() = delete; 70 TimeTraceScope(const TimeTraceScope &) = delete; 71 TimeTraceScope &operator=(const TimeTraceScope &) = delete; 72 TimeTraceScope(TimeTraceScope &&) = delete; 73 TimeTraceScope &operator=(TimeTraceScope &&) = delete; 74 75 TimeTraceScope(StringRef Name) { 76 if (getTimeTraceProfilerInstance() != nullptr) 77 timeTraceProfilerBegin(Name, StringRef("")); 78 } 79 TimeTraceScope(StringRef Name, StringRef Detail) { 80 if (getTimeTraceProfilerInstance() != nullptr) 81 timeTraceProfilerBegin(Name, Detail); 82 } 83 TimeTraceScope(StringRef Name, llvm::function_ref<std::string()> Detail) { 84 if (getTimeTraceProfilerInstance() != nullptr) 85 timeTraceProfilerBegin(Name, Detail); 86 } 87 ~TimeTraceScope() { 88 if (getTimeTraceProfilerInstance() != nullptr) 89 timeTraceProfilerEnd(); 90 } 91 }; 92 93 } // end namespace llvm 94 95 #endif 96