1 //===-- llvm/ADT/Statistic.h - Easy way to expose stats ---------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source 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
30 #include "llvm/Support/Compiler.h"
34 // StatisticBase - Nontemplated base class for Statistic class...
38 static unsigned NumStats;
40 StatisticBase(const char *name, const char *desc) : Name(name), Desc(desc) {
41 ++NumStats; // Keep track of how many stats are created...
43 // Out of line virtual dtor, to give the vtable etc a home.
44 virtual ~StatisticBase();
46 // destroy - Called by subclass dtor so that we can still invoke virtual
47 // functions on the subclass.
50 // printValue - Overridden by template class to print out the value type...
51 virtual void printValue(std::ostream &o) const = 0;
53 // hasSomeData - Return true if some data has been aquired. Avoid printing
54 // lots of zero counts.
56 virtual bool hasSomeData() const = 0;
59 // Statistic Class - templated on the data type we are monitoring...
60 class Statistic : private StatisticBase {
63 virtual void printValue(std::ostream &o) const { o << Value; }
64 virtual bool hasSomeData() const { return Value != 0; }
66 // Normal constructor, default initialize data item...
67 Statistic(const char *name, const char *desc)
68 : StatisticBase(name, desc), Value(0) {}
70 // Constructor to provide an initial value...
71 Statistic(const unsigned &Val, const char *name, const char *desc)
72 : StatisticBase(name, desc), Value(Val) {}
74 // Print information when destroyed, iff command line option is specified
75 ~Statistic() { destroy(); }
77 // Allow use of this class as the value itself...
78 operator unsigned() const { return Value; }
79 const Statistic &operator=(unsigned Val) { Value = Val; return *this; }
80 const Statistic &operator++() { ++Value; return *this; }
81 unsigned operator++(int) { return Value++; }
82 const Statistic &operator--() { --Value; return *this; }
83 unsigned operator--(int) { return Value--; }
84 const Statistic &operator+=(const unsigned &V) { Value += V; return *this; }
85 const Statistic &operator-=(const unsigned &V) { Value -= V; return *this; }
86 const Statistic &operator*=(const unsigned &V) { Value *= V; return *this; }
87 const Statistic &operator/=(const unsigned &V) { Value /= V; return *this; }
90 } // End llvm namespace