# 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, ParserError import sys import parse_histograms 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, key_index, key_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, %d, %d, %s, %s, %s }," % (histogram.low(), histogram.high(), histogram.n_buckets(), histogram.nsITelemetry_kind(), name_index, exp_index, histogram.dataset(), label_index, label_count, key_index, key_count, " | ".join(histogram.record_in_processes_enum()), "true" if histogram.keyed() else "false", " | ".join(histogram.products_enum())), file=output) if cpp_guard: print("#endif", file=output) def write_histogram_table(output, histograms): string_table = StringTable() label_table = [] label_count = 0 keys_table = [] keys_count = 0 print("constexpr HistogramInfo gHistogramInfos[] = {", 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) keys = histogram.keys() key_index = 0 if len(keys) > 0: key_index = keys_count keys_table.append((histogram.name(), string_table.stringIndexes(keys))) keys_count += len(keys) print_array_entry(output, histogram, name_index, exp_index, label_index, len(labels), key_index, len(keys)) 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) print("\nconst uint32_t gHistogramKeyTable[] = {", file=output) for name, indexes in keys_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: kind = histogram.kind() if kind not in table: raise Exception('Unknown kind "%s" for histogram "%s".' % (kind, histogram.name())) fn = table[kind] fn(output, histogram) def write_histogram_ranges(output, histograms): # This generates static data to avoid costly initialization of histograms # (especially exponential ones which require log and exp calls) at runtime. # The format must exactly match that required in histogram.cc, which is # 0, buckets..., INT_MAX. Additionally, the list ends in a 0 to aid asserts # that validate that the length of the ranges list is correct.U cache miss. print("const int gHistogramBucketLowerBounds[] = {", file=output) # Print the dummy buckets for expired histograms, and set the offset to match. print("0,1,2,INT_MAX,", file=output) offset = 4 ranges_offsets = {} for histogram in histograms: ranges = tuple(histogram.ranges()) if ranges not in ranges_offsets: ranges_offsets[ranges] = offset # Suffix each ranges listing with INT_MAX, to match histogram.cc's # expected format. offset += len(ranges) + 1 print(','.join(map(str, ranges)), ',INT_MAX,', file=output) print("0};", file=output) if offset > 32767: raise Exception('Histogram offsets exceeded maximum value for an int16_t.') print("const int16_t gHistogramBucketLowerBoundIndex[] = {", file=output) for histogram in histograms: cpp_guard = histogram.cpp_guard() if cpp_guard: print("#if defined(%s)" % cpp_guard, file=output) our_offset = ranges_offsets[tuple(histogram.ranges())] print("%d," % our_offset, file=output) if cpp_guard: print("#endif", file=output) print("};", file=output) def main(output, *filenames): try: histograms = list(parse_histograms.from_files(filenames)) except ParserError as ex: print("\nError processing histograms:\n" + str(ex) + "\n") sys.exit(1) print(banner, file=output) write_histogram_table(output, histograms) write_histogram_ranges(output, histograms) write_histogram_static_asserts(output, histograms) if __name__ == '__main__': main(sys.stdout, *sys.argv[1:])