1 //===-- llvm/ADT/Statistic.h - Easy way to expose stats ---------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the 'Statistic' class, which is designed to be an easy way
11 // to expose various metrics from passes. These statistics are printed at the
12 // end of a run (from llvm_shutdown), when the -stats command line option is
13 // passed on the command line.
15 // This is useful for reporting information like the number of instructions
16 // simplified, optimized or removed by various transformations, like this:
18 // static Statistic NumInstsKilled("gcse", "Number of instructions killed");
20 // Later, in the code: ++NumInstsKilled;
22 // NOTE: Statistics *must* be declared as global variables.
24 //===----------------------------------------------------------------------===//
26 #ifndef LLVM_ADT_STATISTIC_H
27 #define LLVM_ADT_STATISTIC_H
29 #include "llvm/Config/llvm-config.h"
30 #include "llvm/Support/Compiler.h"
35 // Determine whether statistics should be enabled. We must do it here rather
36 // than in CMake because multi-config generators cannot determine this at
38 #if !defined(NDEBUG) || LLVM_FORCE_ENABLE_STATS
39 #define LLVM_ENABLE_STATS 1
50 const char *DebugType;
53 std::atomic<unsigned> Value;
54 std::atomic<bool> Initialized;
56 unsigned getValue() const { return Value.load(std::memory_order_relaxed); }
57 const char *getDebugType() const { return DebugType; }
58 const char *getName() const { return Name; }
59 const char *getDesc() const { return Desc; }
61 /// construct - This should only be called for non-global statistics.
62 void construct(const char *debugtype, const char *name, const char *desc) {
63 DebugType = debugtype;
70 // Allow use of this class as the value itself.
71 operator unsigned() const { return getValue(); }
74 const Statistic &operator=(unsigned Val) {
75 Value.store(Val, std::memory_order_relaxed);
79 const Statistic &operator++() {
80 Value.fetch_add(1, std::memory_order_relaxed);
84 unsigned operator++(int) {
86 return Value.fetch_add(1, std::memory_order_relaxed);
89 const Statistic &operator--() {
90 Value.fetch_sub(1, std::memory_order_relaxed);
94 unsigned operator--(int) {
96 return Value.fetch_sub(1, std::memory_order_relaxed);
99 const Statistic &operator+=(unsigned V) {
102 Value.fetch_add(V, std::memory_order_relaxed);
106 const Statistic &operator-=(unsigned V) {
109 Value.fetch_sub(V, std::memory_order_relaxed);
113 void updateMax(unsigned V) {
114 unsigned PrevMax = Value.load(std::memory_order_relaxed);
115 // Keep trying to update max until we succeed or another thread produces
116 // a bigger max than us.
117 while (V > PrevMax && !Value.compare_exchange_weak(
118 PrevMax, V, std::memory_order_relaxed)) {
123 #else // Statistics are disabled in release builds.
125 const Statistic &operator=(unsigned Val) {
129 const Statistic &operator++() {
133 unsigned operator++(int) {
137 const Statistic &operator--() {
141 unsigned operator--(int) {
145 const Statistic &operator+=(const unsigned &V) {
149 const Statistic &operator-=(const unsigned &V) {
153 void updateMax(unsigned V) {}
155 #endif // LLVM_ENABLE_STATS
159 if (!Initialized.load(std::memory_order_acquire))
164 void RegisterStatistic();
167 // STATISTIC - A macro to make definition of statistics really simple. This
168 // automatically passes the DEBUG_TYPE of the file into the statistic.
169 #define STATISTIC(VARNAME, DESC) \
170 static llvm::Statistic VARNAME = {DEBUG_TYPE, #VARNAME, DESC, {0}, {false}}
172 /// \brief Enable the collection and printing of statistics.
173 void EnableStatistics(bool PrintOnExit = true);
175 /// \brief Check if statistics are enabled.
176 bool AreStatisticsEnabled();
178 /// \brief Return a file stream to print our output on.
179 std::unique_ptr<raw_fd_ostream> CreateInfoOutputFile();
181 /// \brief Print statistics to the file returned by CreateInfoOutputFile().
182 void PrintStatistics();
184 /// \brief Print statistics to the given output stream.
185 void PrintStatistics(raw_ostream &OS);
187 /// Print statistics in JSON format. This does include all global timers (\see
188 /// Timer, TimerGroup). Note that the timers are cleared after printing and will
189 /// not be printed in human readable form or in a second call of
190 /// PrintStatisticsJSON().
191 void PrintStatisticsJSON(raw_ostream &OS);
193 /// \brief Get the statistics. This can be used to look up the value of
194 /// statistics without needing to parse JSON.
196 /// This function does not prevent statistics being updated by other threads
197 /// during it's execution. It will return the value at the point that it is
198 /// read. However, it will prevent new statistics from registering until it
200 const std::vector<std::pair<StringRef, unsigned>> GetStatistics();
202 } // end namespace llvm
204 #endif // LLVM_ADT_STATISTIC_H