summaryrefslogtreecommitdiffstats
path: root/toolkit/components/telemetry/gen-histogram-data.py
blob: 8e227201d67250e74f3db988ee1e9d26a23dfd6f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

# Write out histogram information for C++.  The histograms are defined
# in a file provided as a command-line argument.

from __future__ import print_function
from shared_telemetry_utils import StringTable, static_assert

import sys
import histogram_tools
import itertools

banner = """/* This file is auto-generated, see gen-histogram-data.py.  */
"""

def print_array_entry(output, histogram, name_index, exp_index, label_index, label_count):
    cpp_guard = histogram.cpp_guard()
    if cpp_guard:
        print("#if defined(%s)" % cpp_guard, file=output)
    print("  { %s, %s, %s, %s, %d, %d, %s, %d, %d, %s }," \
        % (histogram.low(),
           histogram.high(),
           histogram.n_buckets(),
           histogram.nsITelemetry_kind(),
           name_index,
           exp_index,
           histogram.dataset(),
           label_index,
           label_count,
           "true" if histogram.keyed() else "false"), file=output)
    if cpp_guard:
        print("#endif", file=output)

def write_histogram_table(output, histograms):
    string_table = StringTable()
    label_table = []
    label_count = 0

    print("const HistogramInfo gHistograms[] = {", file=output)
    for histogram in histograms:
        name_index = string_table.stringIndex(histogram.name())
        exp_index = string_table.stringIndex(histogram.expiration())

        labels = histogram.labels()
        label_index = 0
        if len(labels) > 0:
            label_index = label_count
            label_table.append((histogram.name(), string_table.stringIndexes(labels)))
            label_count += len(labels)

        print_array_entry(output, histogram,
                          name_index, exp_index,
                          label_index, len(labels))
    print("};\n", file=output)

    strtab_name = "gHistogramStringTable"
    string_table.writeDefinition(output, strtab_name)
    static_assert(output, "sizeof(%s) <= UINT32_MAX" % strtab_name,
                  "index overflow")

    print("\nconst uint32_t gHistogramLabelTable[] = {", file=output)
    for name,indexes in label_table:
        print("/* %s */ %s," % (name, ", ".join(map(str, indexes))), file=output)
    print("};", file=output)


# Write out static asserts for histogram data.  We'd prefer to perform
# these checks in this script itself, but since several histograms
# (generally enumerated histograms) use compile-time constants for
# their upper bounds, we have to let the compiler do the checking.

def static_asserts_for_boolean(output, histogram):
    pass

def static_asserts_for_flag(output, histogram):
    pass

def static_asserts_for_count(output, histogram):
    pass

def static_asserts_for_enumerated(output, histogram):
    n_values = histogram.high()
    static_assert(output, "%s > 2" % n_values,
                  "Not enough values for %s" % histogram.name())

def shared_static_asserts(output, histogram):
    name = histogram.name()
    low = histogram.low()
    high = histogram.high()
    n_buckets = histogram.n_buckets()
    static_assert(output, "%s < %s" % (low, high), "low >= high for %s" % name)
    static_assert(output, "%s > 2" % n_buckets, "Not enough values for %s" % name)
    static_assert(output, "%s >= 1" % low, "Incorrect low value for %s" % name)
    static_assert(output, "%s > %s" % (high, n_buckets),
                  "high must be > number of buckets for %s; you may want an enumerated histogram" % name)

def static_asserts_for_linear(output, histogram):
    shared_static_asserts(output, histogram)

def static_asserts_for_exponential(output, histogram):
    shared_static_asserts(output, histogram)

def write_histogram_static_asserts(output, histograms):
    print("""
// Perform the checks at the beginning of HistogramGet at
// compile time, so that incorrect histogram definitions
// give compile-time errors, not runtime errors.""", file=output)

    table = {
        'boolean' : static_asserts_for_boolean,
        'flag' : static_asserts_for_flag,
        'count': static_asserts_for_count,
        'enumerated' : static_asserts_for_enumerated,
        'categorical' : static_asserts_for_enumerated,
        'linear' : static_asserts_for_linear,
        'exponential' : static_asserts_for_exponential,
        }

    for histogram in histograms:
        histogram_tools.table_dispatch(histogram.kind(), table,
                                       lambda f: f(output, histogram))

def write_debug_histogram_ranges(output, histograms):
    ranges_lengths = []

    # Collect all the range information from individual histograms.
    # Write that information out as well.
    print("#ifdef DEBUG", file=output)
    print("const int gBucketLowerBounds[] = {", file=output)
    for histogram in histograms:
        ranges = []
        try:
            ranges = histogram.ranges()
        except histogram_tools.DefinitionException:
            pass
        ranges_lengths.append(len(ranges))
        # Note that we do not test cpp_guard here.  We do this so we
        # will have complete information about all the histograms in
        # this array.  Just having information about the ranges of
        # histograms is not platform-specific; if there are histograms
        # that have platform-specific constants in their definitions,
        # those histograms will fail in the .ranges() call above and
        # we'll have a zero-length array to deal with here.
        if len(ranges) > 0:
            print(','.join(map(str, ranges)), ',', file=output)
        else:
            print('/* Skipping %s */' % histogram.name(), file=output)
    print("};", file=output)

    # Write the offsets into gBucketLowerBounds.
    print("struct bounds { int offset; int length; };", file=output)
    print("const struct bounds gBucketLowerBoundIndex[] = {", file=output)
    offset = 0
    for (histogram, range_length) in itertools.izip(histograms, ranges_lengths):
        cpp_guard = histogram.cpp_guard()
        # We do test cpp_guard here, so that histogram IDs are valid
        # indexes into this array.
        if cpp_guard:
            print("#if defined(%s)" % cpp_guard, file=output)
        print("{ %d, %d }," % (offset, range_length), file=output)
        if cpp_guard:
            print("#endif", file=output)
        offset += range_length
    print("};", file=output)
    print("#endif", file=output)

def main(output, *filenames):
    histograms = list(histogram_tools.from_files(filenames))

    print(banner, file=output)
    write_histogram_table(output, histograms)
    write_histogram_static_asserts(output, histograms)
    write_debug_histogram_ranges(output, histograms)

if __name__ == '__main__':
    main(sys.stdout, *sys.argv[1:])