LLVM  7.0.0svn
Statistic.cpp
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1 //===-- Statistic.cpp - Easy way to expose stats information --------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements the 'Statistic' class, which is designed to be an easy
11 // way to expose various success metrics from passes. These statistics are
12 // printed at the end of a run, when the -stats command line option is enabled
13 // on the command line.
14 //
15 // This is useful for reporting information like the number of instructions
16 // simplified, optimized or removed by various transformations, like this:
17 //
18 // static Statistic NumInstEliminated("GCSE", "Number of instructions killed");
19 //
20 // Later, in the code: ++NumInstEliminated;
21 //
22 //===----------------------------------------------------------------------===//
23 
24 #include "llvm/ADT/Statistic.h"
25 #include "llvm/ADT/StringExtras.h"
27 #include "llvm/Support/Compiler.h"
28 #include "llvm/Support/Debug.h"
29 #include "llvm/Support/Format.h"
31 #include "llvm/Support/Mutex.h"
32 #include "llvm/Support/Timer.h"
35 #include <algorithm>
36 #include <cstring>
37 using namespace llvm;
38 
39 /// -stats - Command line option to cause transformations to emit stats about
40 /// what they did.
41 ///
42 static cl::opt<bool> Stats(
43  "stats",
44  cl::desc("Enable statistics output from program (available with Asserts)"),
45  cl::Hidden);
46 
47 static cl::opt<bool> StatsAsJSON("stats-json",
48  cl::desc("Display statistics as json data"),
49  cl::Hidden);
50 
51 static bool Enabled;
52 static bool PrintOnExit;
53 
54 namespace {
55 /// This class is used in a ManagedStatic so that it is created on demand (when
56 /// the first statistic is bumped) and destroyed only when llvm_shutdown is
57 /// called. We print statistics from the destructor.
58 /// This class is also used to look up statistic values from applications that
59 /// use LLVM.
60 class StatisticInfo {
61  std::vector<Statistic*> Stats;
62 
63  friend void llvm::PrintStatistics();
64  friend void llvm::PrintStatistics(raw_ostream &OS);
65  friend void llvm::PrintStatisticsJSON(raw_ostream &OS);
66 
67  /// Sort statistics by debugtype,name,description.
68  void sort();
69 public:
70  using const_iterator = std::vector<Statistic *>::const_iterator;
71 
72  StatisticInfo();
73  ~StatisticInfo();
74 
75  void addStatistic(Statistic *S) {
76  Stats.push_back(S);
77  }
78 
79  const_iterator begin() const { return Stats.begin(); }
80  const_iterator end() const { return Stats.end(); }
81  iterator_range<const_iterator> statistics() const {
82  return {begin(), end()};
83  }
84 
85  void reset();
86 };
87 } // end anonymous namespace
88 
91 
92 /// RegisterStatistic - The first time a statistic is bumped, this method is
93 /// called.
95  // If stats are enabled, inform StatInfo that this statistic should be
96  // printed.
97  // llvm_shutdown calls destructors while holding the ManagedStatic mutex.
98  // These destructors end up calling PrintStatistics, which takes StatLock.
99  // Since dereferencing StatInfo and StatLock can require taking the
100  // ManagedStatic mutex, doing so with StatLock held would lead to a lock
101  // order inversion. To avoid that, we dereference the ManagedStatics first,
102  // and only take StatLock afterwards.
103  if (!Initialized.load(std::memory_order_relaxed)) {
105  StatisticInfo &SI = *StatInfo;
106  sys::SmartScopedLock<true> Writer(Lock);
107  // Check Initialized again after acquiring the lock.
108  if (Initialized.load(std::memory_order_relaxed))
109  return;
110  if (Stats || Enabled)
111  SI.addStatistic(this);
112 
113  // Remember we have been registered.
114  Initialized.store(true, std::memory_order_release);
115  }
116 }
117 
118 StatisticInfo::StatisticInfo() {
119  // Ensure timergroup lists are created first so they are destructed after us.
121 }
122 
123 // Print information when destroyed, iff command line option is specified.
124 StatisticInfo::~StatisticInfo() {
125  if (::Stats || PrintOnExit)
127 }
128 
129 void llvm::EnableStatistics(bool PrintOnExit) {
130  Enabled = true;
132 }
133 
135  return Enabled || Stats;
136 }
137 
138 void StatisticInfo::sort() {
139  std::stable_sort(Stats.begin(), Stats.end(),
140  [](const Statistic *LHS, const Statistic *RHS) {
141  if (int Cmp = std::strcmp(LHS->getDebugType(), RHS->getDebugType()))
142  return Cmp < 0;
143 
144  if (int Cmp = std::strcmp(LHS->getName(), RHS->getName()))
145  return Cmp < 0;
146 
147  return std::strcmp(LHS->getDesc(), RHS->getDesc()) < 0;
148  });
149 }
150 
151 void StatisticInfo::reset() {
152  sys::SmartScopedLock<true> Writer(*StatLock);
153 
154  // Tell each statistic that it isn't registered so it has to register
155  // again. We're holding the lock so it won't be able to do so until we're
156  // finished. Once we've forced it to re-register (after we return), then zero
157  // the value.
158  for (auto *Stat : Stats) {
159  // Value updates to a statistic that complete before this statement in the
160  // iteration for that statistic will be lost as intended.
161  Stat->Initialized = false;
162  Stat->Value = 0;
163  }
164 
165  // Clear the registration list and release the lock once we're done. Any
166  // pending updates from other threads will safely take effect after we return.
167  // That might not be what the user wants if they're measuring a compilation
168  // but it's their responsibility to prevent concurrent compilations to make
169  // a single compilation measurable.
170  Stats.clear();
171 }
172 
174  StatisticInfo &Stats = *StatInfo;
175 
176  // Figure out how long the biggest Value and Name fields are.
177  unsigned MaxDebugTypeLen = 0, MaxValLen = 0;
178  for (size_t i = 0, e = Stats.Stats.size(); i != e; ++i) {
179  MaxValLen = std::max(MaxValLen,
180  (unsigned)utostr(Stats.Stats[i]->getValue()).size());
181  MaxDebugTypeLen = std::max(MaxDebugTypeLen,
182  (unsigned)std::strlen(Stats.Stats[i]->getDebugType()));
183  }
184 
185  Stats.sort();
186 
187  // Print out the statistics header...
188  OS << "===" << std::string(73, '-') << "===\n"
189  << " ... Statistics Collected ...\n"
190  << "===" << std::string(73, '-') << "===\n\n";
191 
192  // Print all of the statistics.
193  for (size_t i = 0, e = Stats.Stats.size(); i != e; ++i)
194  OS << format("%*u %-*s - %s\n",
195  MaxValLen, Stats.Stats[i]->getValue(),
196  MaxDebugTypeLen, Stats.Stats[i]->getDebugType(),
197  Stats.Stats[i]->getDesc());
198 
199  OS << '\n'; // Flush the output stream.
200  OS.flush();
201 }
202 
204  sys::SmartScopedLock<true> Reader(*StatLock);
205  StatisticInfo &Stats = *StatInfo;
206 
207  Stats.sort();
208 
209  // Print all of the statistics.
210  OS << "{\n";
211  const char *delim = "";
212  for (const Statistic *Stat : Stats.Stats) {
213  OS << delim;
214  assert(yaml::needsQuotes(Stat->getDebugType()) == yaml::QuotingType::None &&
215  "Statistic group/type name is simple.");
216  assert(yaml::needsQuotes(Stat->getName()) == yaml::QuotingType::None &&
217  "Statistic name is simple");
218  OS << "\t\"" << Stat->getDebugType() << '.' << Stat->getName() << "\": "
219  << Stat->getValue();
220  delim = ",\n";
221  }
222  // Print timers.
224 
225  OS << "\n}\n";
226  OS.flush();
227 }
228 
230 #if LLVM_ENABLE_STATS
231  sys::SmartScopedLock<true> Reader(*StatLock);
232  StatisticInfo &Stats = *StatInfo;
233 
234  // Statistics not enabled?
235  if (Stats.Stats.empty()) return;
236 
237  // Get the stream to write to.
238  std::unique_ptr<raw_ostream> OutStream = CreateInfoOutputFile();
239  if (StatsAsJSON)
240  PrintStatisticsJSON(*OutStream);
241  else
242  PrintStatistics(*OutStream);
243 
244 #else
245  // Check if the -stats option is set instead of checking
246  // !Stats.Stats.empty(). In release builds, Statistics operators
247  // do nothing, so stats are never Registered.
248  if (Stats) {
249  // Get the stream to write to.
250  std::unique_ptr<raw_ostream> OutStream = CreateInfoOutputFile();
251  (*OutStream) << "Statistics are disabled. "
252  << "Build with asserts or with -DLLVM_ENABLE_STATS\n";
253  }
254 #endif
255 }
256 
257 const std::vector<std::pair<StringRef, unsigned>> llvm::GetStatistics() {
258  sys::SmartScopedLock<true> Reader(*StatLock);
259  std::vector<std::pair<StringRef, unsigned>> ReturnStats;
260 
261  for (const auto &Stat : StatInfo->statistics())
262  ReturnStats.emplace_back(Stat->getName(), Stat->getValue());
263  return ReturnStats;
264 }
265 
267  StatInfo->reset();
268 }
const NoneType None
Definition: None.h:24
static bool PrintOnExit
Definition: Statistic.cpp:52
const_iterator end(StringRef path)
Get end iterator over path.
Definition: Path.cpp:250
GCNRegPressure max(const GCNRegPressure &P1, const GCNRegPressure &P2)
void EnableStatistics(bool PrintOnExit=true)
Enable the collection and printing of statistics.
Definition: Statistic.cpp:129
const_iterator begin(StringRef path, Style style=Style::native)
Get begin iterator over path.
Definition: Path.cpp:241
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
format_object< Ts... > format(const char *Fmt, const Ts &... Vals)
These are helper functions used to produce formatted output.
Definition: Format.h:124
SmartMutex - A mutex with a compile time constant parameter that indicates whether this mutex should ...
Definition: Mutex.h:92
static sys::Mutex Lock
void RegisterStatistic()
RegisterStatistic - The first time a statistic is bumped, this method is called.
Definition: Statistic.cpp:94
void ResetStatistics()
Reset the statistics.
Definition: Statistic.cpp:266
const char * getDebugType() const
Definition: Statistic.h:57
friend const_iterator begin(StringRef path, Style style)
Get begin iterator over path.
Definition: Path.cpp:241
static ManagedStatic< StatisticInfo > StatInfo
Definition: Statistic.cpp:89
std::unique_ptr< raw_fd_ostream > CreateInfoOutputFile()
Return a file stream to print our output on.
Definition: Timer.cpp:55
friend const_iterator end(StringRef path)
Get end iterator over path.
Definition: Path.cpp:250
const std::vector< std::pair< StringRef, unsigned > > GetStatistics()
Get the statistics.
Definition: Statistic.cpp:257
void sort(IteratorTy Start, IteratorTy End)
Definition: STLExtras.h:859
void PrintStatisticsJSON(raw_ostream &OS)
Print statistics in JSON format.
Definition: Statistic.cpp:203
auto size(R &&Range, typename std::enable_if< std::is_same< typename std::iterator_traits< decltype(Range.begin())>::iterator_category, std::random_access_iterator_tag >::value, void >::type *=nullptr) -> decltype(std::distance(Range.begin(), Range.end()))
Get the size of a range.
Definition: STLExtras.h:1032
unsigned getValue() const
Definition: Statistic.h:56
const char * getDesc() const
Definition: Statistic.h:59
std::string utostr(uint64_t X, bool isNeg=false)
Definition: StringExtras.h:203
static bool Enabled
Definition: Statistic.cpp:51
A range adaptor for a pair of iterators.
static const char * printAllJSONValues(raw_ostream &OS, const char *delim)
Prints all timers as JSON key/value pairs, and clears them all out.
Definition: Timer.cpp:412
const char * getName() const
Definition: Statistic.h:58
void PrintStatistics()
Print statistics to the file returned by CreateInfoOutputFile().
Definition: Statistic.cpp:229
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
static void ConstructTimerLists()
Ensure global timer group lists are initialized.
Definition: Timer.cpp:419
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:46
static cl::opt< bool > Stats("stats", cl::desc("Enable statistics output from program (available with Asserts)"), cl::Hidden)
-stats - Command line option to cause transformations to emit stats about what they did...
ManagedStatic - This transparently changes the behavior of global statics to be lazily constructed on...
Definition: ManagedStatic.h:61
static ManagedStatic< sys::SmartMutex< true > > StatLock
Definition: Statistic.cpp:90
bool AreStatisticsEnabled()
Check if statistics are enabled.
Definition: Statistic.cpp:134
static cl::opt< bool > StatsAsJSON("stats-json", cl::desc("Display statistics as json data"), cl::Hidden)