llvm-6502/include/llvm/ADT/Statistic.h
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

140 lines
3.8 KiB
C++

//===-- llvm/ADT/Statistic.h - Easy way to expose stats ---------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the 'Statistic' class, which is designed to be an easy way
// to expose various metrics from passes. These statistics are printed at the
// end of a run (from llvm_shutdown), when the -stats command line option is
// passed 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 NumInstsKilled("gcse", "Number of instructions killed");
//
// Later, in the code: ++NumInstsKilled;
//
// NOTE: Statistics *must* be declared as global variables.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ADT_STATISTIC_H
#define LLVM_ADT_STATISTIC_H
#include "llvm/Support/Atomic.h"
#include "llvm/Support/Valgrind.h"
namespace llvm {
class raw_ostream;
class Statistic {
public:
const char *Name;
const char *Desc;
volatile llvm::sys::cas_flag Value;
bool Initialized;
llvm::sys::cas_flag getValue() const { return Value; }
const char *getName() const { return Name; }
const char *getDesc() const { return Desc; }
/// construct - This should only be called for non-global statistics.
void construct(const char *name, const char *desc) {
Name = name; Desc = desc;
Value = 0; Initialized = 0;
}
// Allow use of this class as the value itself.
operator unsigned() const { return Value; }
const Statistic &operator=(unsigned Val) {
Value = Val;
return init();
}
const Statistic &operator++() {
// FIXME: This function and all those that follow carefully use an
// atomic operation to update the value safely in the presence of
// concurrent accesses, but not to read the return value, so the
// return value is not thread safe.
sys::AtomicIncrement(&Value);
return init();
}
unsigned operator++(int) {
init();
unsigned OldValue = Value;
sys::AtomicIncrement(&Value);
return OldValue;
}
const Statistic &operator--() {
sys::AtomicDecrement(&Value);
return init();
}
unsigned operator--(int) {
init();
unsigned OldValue = Value;
sys::AtomicDecrement(&Value);
return OldValue;
}
const Statistic &operator+=(const unsigned &V) {
if (!V) return *this;
sys::AtomicAdd(&Value, V);
return init();
}
const Statistic &operator-=(const unsigned &V) {
if (!V) return *this;
sys::AtomicAdd(&Value, -V);
return init();
}
const Statistic &operator*=(const unsigned &V) {
sys::AtomicMul(&Value, V);
return init();
}
const Statistic &operator/=(const unsigned &V) {
sys::AtomicDiv(&Value, V);
return init();
}
protected:
Statistic &init() {
bool tmp = Initialized;
sys::MemoryFence();
if (!tmp) RegisterStatistic();
TsanHappensAfter(this);
return *this;
}
void RegisterStatistic();
};
// STATISTIC - A macro to make definition of statistics really simple. This
// automatically passes the DEBUG_TYPE of the file into the statistic.
#define STATISTIC(VARNAME, DESC) \
static llvm::Statistic VARNAME = { DEBUG_TYPE, DESC, 0, 0 }
/// \brief Enable the collection and printing of statistics.
void EnableStatistics();
/// \brief Check if statistics are enabled.
bool AreStatisticsEnabled();
/// \brief Print statistics to the file returned by CreateInfoOutputFile().
void PrintStatistics();
/// \brief Print statistics to the given output stream.
void PrintStatistics(raw_ostream &OS);
} // End llvm namespace
#endif