Statistic.h revision fa10fdf5eb9305d8af2f4c63264400bb17e6aa3f 
1//===-- Support/StatisticReporter.h - Easy way to expose stats ---*- C++ -*-==//
2//
3// This file defines the 'Statistic' class, which is designed to be an easy way
4// to expose various success metrics from passes.  These statistics are printed
5// at the end of a run, when the -stats command line option is enabled on the
6// command line.
7//
8// This is useful for reporting information like the number of instructions
9// simplified, optimized or removed by various transformations, like this:
10//
11// static Statistic<> NumInstEliminated("GCSE - Number of instructions killed");
12//
13// Later, in the code: ++NumInstEliminated;
14//
15//===----------------------------------------------------------------------===//
16
17#ifndef SUPPORT_STATISTIC_REPORTER_H
18#define SUPPORT_STATISTIC_REPORTER_H
19
20#include <iosfwd>
21
22// StatisticBase - Nontemplated base class for Statistic<> class...
23class StatisticBase {
24  const char *Name;
25protected:
26  StatisticBase(const char *name) : Name(name) {}
27  virtual ~StatisticBase() {}
28
29  // destroy - Called by subclass dtor so that we can still invoke virtual
30  // functions on the subclass.
31  void destroy() const;
32
33  // printValue - Overridden by template class to print out the value type...
34  virtual void printValue(ostream &o) const = 0;
35
36  // hasSomeData - Return true if some data has been aquired.  Avoid printing
37  // lots of zero counts.
38  //
39  virtual bool hasSomeData() const = 0;
40};
41
42// Statistic Class - templated on the data type we are monitoring...
43template <typename DataType=unsigned>
44class Statistic : private StatisticBase {
45  DataType Value;
46
47  virtual void printValue(ostream &o) const { o << Value; }
48  virtual bool hasSomeData() const { return Value != DataType(); }
49public:
50  // Normal constructor, default initialize data item...
51  Statistic(const char *name) : StatisticBase(name), Value(DataType()) {}
52
53  // Constructor to provide an initial value...
54  Statistic(const DataType &Val, const char *name)
55    : StatisticBase(name), Value(Val) {}
56
57  // Print information when destroyed, iff command line option is specified
58  ~Statistic() { destroy(); }
59
60  // Allow use of this class as the value itself...
61  inline operator DataType() const { return Value; }
62  inline const DataType &operator=(DataType Val) { Value = Val; return Value; }
63  inline const DataType &operator++() { return ++Value; }
64  inline DataType operator++(int) { return Value++; }
65  inline const DataType &operator+=(const DataType &V) { return Value += V; }
66  inline const DataType &operator-=(const DataType &V) { return Value -= V; }
67};
68
69#endif
70