1 files changed, 265 insertions, 0 deletions
diff --git a/llvm/lib/Support/Statistic.cpp b/llvm/lib/Support/Statistic.cpp
new file mode 100644
index 000000000000..8b4177c7fba6
--- /dev/null
+++ b/llvm/lib/Support/Statistic.cpp
@@ -0,0 +1,265 @@
+//===-- Statistic.cpp - Easy way to expose stats information --------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the 'Statistic' class, which is designed to be an easy
+// way to expose various success metrics from passes.  These statistics are
+// printed at the end of a run, when the -stats command line option is enabled
+// on the command line.
+//
+// This is useful for reporting information like the number of instructions
+// simplified, optimized or removed by various transformations, like this:
+//
+// static Statistic NumInstEliminated("GCSE", "Number of instructions killed");
+//
+// Later, in the code: ++NumInstEliminated;
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/Statistic.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/Format.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/Mutex.h"
+#include "llvm/Support/Timer.h"
+#include "llvm/Support/YAMLTraits.h"
+#include "llvm/Support/raw_ostream.h"
+#include <algorithm>
+#include <cstring>
+using namespace llvm;
+
+/// -stats - Command line option to cause transformations to emit stats about
+/// what they did.
+///
+static cl::opt<bool> Stats(
+    "stats",
+    cl::desc("Enable statistics output from program (available with Asserts)"),
+    cl::Hidden);
+
+static cl::opt<bool> StatsAsJSON("stats-json",
+                                 cl::desc("Display statistics as json data"),
+                                 cl::Hidden);
+
+static bool Enabled;
+static bool PrintOnExit;
+
+namespace {
+/// This class is used in a ManagedStatic so that it is created on demand (when
+/// the first statistic is bumped) and destroyed only when llvm_shutdown is
+/// called. We print statistics from the destructor.
+/// This class is also used to look up statistic values from applications that
+/// use LLVM.
+class StatisticInfo {
+  std::vector<TrackingStatistic *> Stats;
+
+  friend void llvm::PrintStatistics();
+  friend void llvm::PrintStatistics(raw_ostream &OS);
+  friend void llvm::PrintStatisticsJSON(raw_ostream &OS);
+
+  /// Sort statistics by debugtype,name,description.
+  void sort();
+public:
+  using const_iterator = std::vector<TrackingStatistic *>::const_iterator;
+
+  StatisticInfo();
+  ~StatisticInfo();
+
+  void addStatistic(TrackingStatistic *S) { Stats.push_back(S); }
+
+  const_iterator begin() const { return Stats.begin(); }
+  const_iterator end() const { return Stats.end(); }
+  iterator_range<const_iterator> statistics() const {
+    return {begin(), end()};
+  }
+
+  void reset();
+};
+} // end anonymous namespace
+
+static ManagedStatic<StatisticInfo> StatInfo;
+static ManagedStatic<sys::SmartMutex<true> > StatLock;
+
+/// RegisterStatistic - The first time a statistic is bumped, this method is
+/// called.
+void TrackingStatistic::RegisterStatistic() {
+  // If stats are enabled, inform StatInfo that this statistic should be
+  // printed.
+  // llvm_shutdown calls destructors while holding the ManagedStatic mutex.
+  // These destructors end up calling PrintStatistics, which takes StatLock.
+  // Since dereferencing StatInfo and StatLock can require taking the
+  // ManagedStatic mutex, doing so with StatLock held would lead to a lock
+  // order inversion. To avoid that, we dereference the ManagedStatics first,
+  // and only take StatLock afterwards.
+  if (!Initialized.load(std::memory_order_relaxed)) {
+    sys::SmartMutex<true> &Lock = *StatLock;
+    StatisticInfo &SI = *StatInfo;
+    sys::SmartScopedLock<true> Writer(Lock);
+    // Check Initialized again after acquiring the lock.
+    if (Initialized.load(std::memory_order_relaxed))
+      return;
+    if (Stats || Enabled)
+      SI.addStatistic(this);
+
+    // Remember we have been registered.
+    Initialized.store(true, std::memory_order_release);
+  }
+}
+
+StatisticInfo::StatisticInfo() {
+  // Ensure timergroup lists are created first so they are destructed after us.
+  TimerGroup::ConstructTimerLists();
+}
+
+// Print information when destroyed, iff command line option is specified.
+StatisticInfo::~StatisticInfo() {
+  if (::Stats || PrintOnExit)
+    llvm::PrintStatistics();
+}
+
+void llvm::EnableStatistics(bool PrintOnExit) {
+  Enabled = true;
+  ::PrintOnExit = PrintOnExit;
+}
+
+bool llvm::AreStatisticsEnabled() {
+  return Enabled || Stats;
+}
+
+void StatisticInfo::sort() {
+  llvm::stable_sort(
+      Stats, [](const TrackingStatistic *LHS, const TrackingStatistic *RHS) {
+        if (int Cmp = std::strcmp(LHS->getDebugType(), RHS->getDebugType()))
+          return Cmp < 0;
+
+        if (int Cmp = std::strcmp(LHS->getName(), RHS->getName()))
+          return Cmp < 0;
+
+        return std::strcmp(LHS->getDesc(), RHS->getDesc()) < 0;
+      });
+}
+
+void StatisticInfo::reset() {
+  sys::SmartScopedLock<true> Writer(*StatLock);
+
+  // Tell each statistic that it isn't registered so it has to register
+  // again. We're holding the lock so it won't be able to do so until we're
+  // finished. Once we've forced it to re-register (after we return), then zero
+  // the value.
+  for (auto *Stat : Stats) {
+    // Value updates to a statistic that complete before this statement in the
+    // iteration for that statistic will be lost as intended.
+    Stat->Initialized = false;
+    Stat->Value = 0;
+  }
+
+  // Clear the registration list and release the lock once we're done. Any
+  // pending updates from other threads will safely take effect after we return.
+  // That might not be what the user wants if they're measuring a compilation
+  // but it's their responsibility to prevent concurrent compilations to make
+  // a single compilation measurable.
+  Stats.clear();
+}
+
+void llvm::PrintStatistics(raw_ostream &OS) {
+  StatisticInfo &Stats = *StatInfo;
+
+  // Figure out how long the biggest Value and Name fields are.
+  unsigned MaxDebugTypeLen = 0, MaxValLen = 0;
+  for (size_t i = 0, e = Stats.Stats.size(); i != e; ++i) {
+    MaxValLen = std::max(MaxValLen,
+                         (unsigned)utostr(Stats.Stats[i]->getValue()).size());
+    MaxDebugTypeLen = std::max(MaxDebugTypeLen,
+                         (unsigned)std::strlen(Stats.Stats[i]->getDebugType()));
+  }
+
+  Stats.sort();
+
+  // Print out the statistics header...
+  OS << "===" << std::string(73, '-') << "===\n"
+     << "                          ... Statistics Collected ...\n"
+     << "===" << std::string(73, '-') << "===\n\n";
+
+  // Print all of the statistics.
+  for (size_t i = 0, e = Stats.Stats.size(); i != e; ++i)
+    OS << format("%*u %-*s - %s\n",
+                 MaxValLen, Stats.Stats[i]->getValue(),
+                 MaxDebugTypeLen, Stats.Stats[i]->getDebugType(),
+                 Stats.Stats[i]->getDesc());
+
+  OS << '\n';  // Flush the output stream.
+  OS.flush();
+}
+
+void llvm::PrintStatisticsJSON(raw_ostream &OS) {
+  sys::SmartScopedLock<true> Reader(*StatLock);
+  StatisticInfo &Stats = *StatInfo;
+
+  Stats.sort();
+
+  // Print all of the statistics.
+  OS << "{\n";
+  const char *delim = "";
+  for (const TrackingStatistic *Stat : Stats.Stats) {
+    OS << delim;
+    assert(yaml::needsQuotes(Stat->getDebugType()) == yaml::QuotingType::None &&
+           "Statistic group/type name is simple.");
+    assert(yaml::needsQuotes(Stat->getName()) == yaml::QuotingType::None &&
+           "Statistic name is simple");
+    OS << "\t\"" << Stat->getDebugType() << '.' << Stat->getName() << "\": "
+       << Stat->getValue();
+    delim = ",\n";
+  }
+  // Print timers.
+  TimerGroup::printAllJSONValues(OS, delim);
+
+  OS << "\n}\n";
+  OS.flush();
+}
+
+void llvm::PrintStatistics() {
+#if LLVM_ENABLE_STATS
+  sys::SmartScopedLock<true> Reader(*StatLock);
+  StatisticInfo &Stats = *StatInfo;
+
+  // Statistics not enabled?
+  if (Stats.Stats.empty()) return;
+
+  // Get the stream to write to.
+  std::unique_ptr<raw_ostream> OutStream = CreateInfoOutputFile();
+  if (StatsAsJSON)
+    PrintStatisticsJSON(*OutStream);
+  else
+    PrintStatistics(*OutStream);
+
+#else
+  // Check if the -stats option is set instead of checking
+  // !Stats.Stats.empty().  In release builds, Statistics operators
+  // do nothing, so stats are never Registered.
+  if (Stats) {
+    // Get the stream to write to.
+    std::unique_ptr<raw_ostream> OutStream = CreateInfoOutputFile();
+    (*OutStream) << "Statistics are disabled.  "
+                 << "Build with asserts or with -DLLVM_ENABLE_STATS\n";
+  }
+#endif
+}
+
+const std::vector<std::pair<StringRef, unsigned>> llvm::GetStatistics() {
+  sys::SmartScopedLock<true> Reader(*StatLock);
+  std::vector<std::pair<StringRef, unsigned>> ReturnStats;
+
+  for (const auto &Stat : StatInfo->statistics())
+    ReturnStats.emplace_back(Stat->getName(), Stat->getValue());
+  return ReturnStats;
+}
+
+void llvm::ResetStatistics() {
+  StatInfo->reset();
+}