llvm-6502/lib/Support/Statistic.cpp
Nick Lewycky aa21e417f2 Silence tsan false-positives (tsan can't track things which are only safe due to
memory fences) in statistics registration, which works the same way that
ManagedStatic registration does.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145869 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-05 23:07:05 +00:00

155 lines
4.7 KiB
C++

//===-- Statistic.cpp - Easy way to expose stats information --------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// 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/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/Mutex.h"
#include "llvm/ADT/StringExtras.h"
#include <algorithm>
#include <cstring>
using namespace llvm;
// CreateInfoOutputFile - Return a file stream to print our output on.
namespace llvm { extern raw_ostream *CreateInfoOutputFile(); }
/// -stats - Command line option to cause transformations to emit stats about
/// what they did.
///
static cl::opt<bool>
Enabled("stats", cl::desc("Enable statistics output from program"));
namespace {
/// StatisticInfo - 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.
class StatisticInfo {
std::vector<const Statistic*> Stats;
friend void llvm::PrintStatistics();
friend void llvm::PrintStatistics(raw_ostream &OS);
public:
~StatisticInfo();
void addStatistic(const Statistic *S) {
Stats.push_back(S);
}
};
}
static ManagedStatic<StatisticInfo> StatInfo;
static ManagedStatic<sys::SmartMutex<true> > StatLock;
/// RegisterStatistic - The first time a statistic is bumped, this method is
/// called.
void Statistic::RegisterStatistic() {
// If stats are enabled, inform StatInfo that this statistic should be
// printed.
sys::SmartScopedLock<true> Writer(*StatLock);
if (!Initialized) {
if (Enabled)
StatInfo->addStatistic(this);
TsanHappensBefore(this);
sys::MemoryFence();
// Remember we have been registered.
TsanIgnoreWritesBegin();
Initialized = true;
TsanIgnoreWritesEnd();
}
}
namespace {
struct NameCompare {
bool operator()(const Statistic *LHS, const Statistic *RHS) const {
int Cmp = std::strcmp(LHS->getName(), RHS->getName());
if (Cmp != 0) return Cmp < 0;
// Secondary key is the description.
return std::strcmp(LHS->getDesc(), RHS->getDesc()) < 0;
}
};
}
// Print information when destroyed, iff command line option is specified.
StatisticInfo::~StatisticInfo() {
llvm::PrintStatistics();
}
void llvm::EnableStatistics() {
Enabled.setValue(true);
}
bool llvm::AreStatisticsEnabled() {
return Enabled;
}
void llvm::PrintStatistics(raw_ostream &OS) {
StatisticInfo &Stats = *StatInfo;
// Figure out how long the biggest Value and Name fields are.
unsigned MaxNameLen = 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());
MaxNameLen = std::max(MaxNameLen,
(unsigned)std::strlen(Stats.Stats[i]->getName()));
}
// Sort the fields by name.
std::stable_sort(Stats.Stats.begin(), Stats.Stats.end(), NameCompare());
// 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(),
MaxNameLen, Stats.Stats[i]->getName(),
Stats.Stats[i]->getDesc());
OS << '\n'; // Flush the output stream.
OS.flush();
}
void llvm::PrintStatistics() {
StatisticInfo &Stats = *StatInfo;
// Statistics not enabled?
if (Stats.Stats.empty()) return;
// Get the stream to write to.
raw_ostream &OutStream = *CreateInfoOutputFile();
PrintStatistics(OutStream);
delete &OutStream; // Close the file.
}