1 //===-- Statistic.cpp - Easy way to expose stats information --------------===//
2 //
3 // This file implements the 'Statistic' class, which is designed to be an easy
4 // way to expose various success metrics from passes.  These statistics are
5 // printed at the end of a run, when the -stats command line option is enabled
6 // on the 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 #include "Support/Statistic.h"
18 #include "Support/CommandLine.h"
19 #include <iostream>
20 #include <sstream>
21 #include <algorithm>
22 
23 bool DebugFlag;  // DebugFlag - Exported boolean set by the -debug option
24 
25 unsigned StatisticBase::NumStats = 0;
26 
27 // -stats - Command line option to cause transformations to emit stats about
28 // what they did.
29 //
30 static cl::opt<bool>
31 Enabled("stats", cl::desc("Enable statistics output from program"));
32 
33 // -debug - Command line option to enable the DEBUG statements in the passes.
34 static cl::opt<bool, true>
35 Debug("debug", cl::desc("Enable debug output"), cl::Hidden,
36       cl::location(DebugFlag));
37 
38 struct StatRecord {
39   std::string Value;
40   const char *Name, *Desc;
41 
42   StatRecord(const std::string V, const char *N, const char *D)
43     : Value(V), Name(N), Desc(D) {}
44 
45   bool operator<(const StatRecord &SR) const {
46     return std::strcmp(Name, SR.Name) < 0;
47   }
48 
49   void print(unsigned ValFieldSize, unsigned NameFieldSize) {
50     std::cerr << std::string(ValFieldSize-Value.length(), ' ')
51               << Value << " " << Name
52               << std::string(NameFieldSize-std::strlen(Name), ' ')
53               << " - " << Desc << "\n";
54   }
55 };
56 
57 static std::vector<StatRecord> *AccumStats = 0;
58 
59 // Print information when destroyed, iff command line option is specified
60 void StatisticBase::destroy() const {
61   if (Enabled && hasSomeData()) {
62     if (AccumStats == 0)
63       AccumStats = new std::vector<StatRecord>();
64 
65     std::ostringstream Out;
66     printValue(Out);
67     AccumStats->push_back(StatRecord(Out.str(), Name, Desc));
68   }
69 
70   if (--NumStats == 0 && AccumStats) {
71     // Figure out how long the biggest Value and Name fields are...
72     unsigned MaxNameLen = 0, MaxValLen = 0;
73     for (unsigned i = 0, e = AccumStats->size(); i != e; ++i) {
74       MaxValLen = std::max(MaxValLen,
75                            (unsigned)(*AccumStats)[i].Value.length());
76       MaxNameLen = std::max(MaxNameLen,
77                             (unsigned)std::strlen((*AccumStats)[i].Name));
78     }
79 
80     // Sort the fields...
81     std::stable_sort(AccumStats->begin(), AccumStats->end());
82 
83     // Print out the statistics header...
84     std::cerr << "===" << std::string(73, '-') << "===\n"
85               << "                          ... Statistics Collected ...\n"
86               << "===" << std::string(73, '-') << "===\n\n";
87 
88     // Print all of the statistics accumulated...
89     for (unsigned i = 0, e = AccumStats->size(); i != e; ++i)
90       (*AccumStats)[i].print(MaxValLen, MaxNameLen);
91 
92     std::cerr << std::endl;  // Flush the output stream...
93 
94     // Free all accumulated statistics...
95     delete AccumStats;
96     AccumStats = 0;
97   }
98 }
99