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/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? 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 73 TimeTraceScope(StringRef Name) { 74 if (getTimeTraceProfilerInstance() != nullptr) 75 timeTraceProfilerBegin(Name, StringRef("")); 76 } 77 TimeTraceScope(StringRef Name, StringRef Detail) { 78 if (getTimeTraceProfilerInstance() != nullptr) 79 timeTraceProfilerBegin(Name, Detail); 80 } 81 TimeTraceScope(StringRef Name, llvm::function_ref<std::string()> Detail) { 82 if (getTimeTraceProfilerInstance() != nullptr) 83 timeTraceProfilerBegin(Name, Detail); 84 } 85 ~TimeTraceScope() { 86 if (getTimeTraceProfilerInstance() != nullptr) 87 timeTraceProfilerEnd(); 88 } 89 }; 90 91 } // end namespace llvm 92 93 #endif 94