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 <sstream>
20 #include <iostream>
21 #include <algorithm>
22 
23 // GetLibSupportInfoOutputFile - Return a file stream to print our output on...
24 std::ostream *GetLibSupportInfoOutputFile();
25 
26 unsigned StatisticBase::NumStats = 0;
27 
28 // -stats - Command line option to cause transformations to emit stats about
29 // what they did.
30 //
31 static cl::opt<bool>
32 Enabled("stats", cl::desc("Enable statistics output from program"));
33 
34 struct StatRecord {
35   std::string Value;
36   const char *Name, *Desc;
37 
38   StatRecord(const std::string V, const char *N, const char *D)
39     : Value(V), Name(N), Desc(D) {}
40 
41   bool operator<(const StatRecord &SR) const {
42     return std::strcmp(Name, SR.Name) < 0;
43   }
44 
45   void print(unsigned ValFieldSize, unsigned NameFieldSize,
46              std::ostream &OS) {
47     OS << std::string(ValFieldSize-Value.length(), ' ')
48        << Value << " " << Name
49        << std::string(NameFieldSize-std::strlen(Name), ' ')
50        << " - " << Desc << "\n";
51   }
52 };
53 
54 static std::vector<StatRecord> *AccumStats = 0;
55 
56 // Print information when destroyed, iff command line option is specified
57 void StatisticBase::destroy() const {
58   if (Enabled && hasSomeData()) {
59     if (AccumStats == 0)
60       AccumStats = new std::vector<StatRecord>();
61 
62     std::ostringstream Out;
63     printValue(Out);
64     AccumStats->push_back(StatRecord(Out.str(), Name, Desc));
65   }
66 
67   if (--NumStats == 0 && AccumStats) {
68     std::ostream *OutStream = GetLibSupportInfoOutputFile();
69 
70     // Figure out how long the biggest Value and Name fields are...
71     unsigned MaxNameLen = 0, MaxValLen = 0;
72     for (unsigned i = 0, e = AccumStats->size(); i != e; ++i) {
73       MaxValLen = std::max(MaxValLen,
74                            (unsigned)(*AccumStats)[i].Value.length());
75       MaxNameLen = std::max(MaxNameLen,
76                             (unsigned)std::strlen((*AccumStats)[i].Name));
77     }
78 
79     // Sort the fields...
80     std::stable_sort(AccumStats->begin(), AccumStats->end());
81 
82     // Print out the statistics header...
83     *OutStream << "===" << std::string(73, '-') << "===\n"
84                << "                          ... Statistics Collected ...\n"
85                << "===" << std::string(73, '-') << "===\n\n";
86 
87     // Print all of the statistics accumulated...
88     for (unsigned i = 0, e = AccumStats->size(); i != e; ++i)
89       (*AccumStats)[i].print(MaxValLen, MaxNameLen, *OutStream);
90 
91     *OutStream << std::endl;  // Flush the output stream...
92 
93     // Free all accumulated statistics...
94     delete AccumStats;
95     AccumStats = 0;
96     if (OutStream != &std::cerr && OutStream != &std::cout)
97       delete OutStream;   // Close the file...
98   }
99 }
100