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# 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
# Write out histogram information for C++. The histograms are defined
# in a file provided as a command-line argument.
import sys
from os import path
import buildconfig
from mozparsers import parse_histograms
from mozparsers.shared_telemetry_utils import ParserError, static_assert
COMPONENTS_PATH = path.abspath(
path.join(path.dirname(__file__), path.pardir, path.pardir)
)
sys.path.append(
path.join(COMPONENTS_PATH, "glean", "build_scripts", "glean_parser_ext")
)
from string_table import StringTable
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,
store_index,
store_count,
):
if histogram.record_on_os(buildconfig.substs["OS_TARGET"]):
print(
" { %d, %d, %d, %d, %d, %d, %d, %d, %d, %d, %s, %s, %s, %s, %s, %s },"
% (
histogram.low(),
histogram.high(),
histogram.n_buckets(),
name_index,
exp_index,
label_count,
key_count,
store_count,
label_index,
key_index,
store_index,
" | ".join(histogram.record_in_processes_enum()),
"true" if histogram.keyed() else "false",
histogram.nsITelemetry_kind(),
histogram.dataset(),
" | ".join(histogram.products_enum()),
),
file=output,
)
def write_histogram_table(output, histograms):
string_table = StringTable()
label_table = []
label_count = 0
keys_table = []
keys_count = 0
store_table = []
total_store_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)
stores = histogram.record_into_store()
store_index = 0
if stores == ["main"]:
# if count == 1 && offset == UINT16_MAX -> only main store
store_index = "UINT16_MAX"
else:
store_index = total_store_count
store_table.append((histogram.name(), string_table.stringIndexes(stores)))
total_store_count += len(stores)
print_array_entry(
output,
histogram,
name_index,
exp_index,
label_index,
len(labels),
key_index,
len(keys),
store_index,
len(stores),
)
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("\n#if defined(_MSC_VER) && !defined(__clang__)", file=output)
print("const uint32_t gHistogramLabelTable[] = {", file=output)
print("#else", file=output)
print("constexpr uint32_t gHistogramLabelTable[] = {", file=output)
print("#endif", file=output)
for name, indexes in label_table:
print("/* %s */ %s," % (name, ", ".join(map(str, indexes))), file=output)
print("};", file=output)
static_assert(
output, "sizeof(gHistogramLabelTable) <= UINT16_MAX", "index overflow"
)
print("\n#if defined(_MSC_VER) && !defined(__clang__)", file=output)
print("const uint32_t gHistogramKeyTable[] = {", file=output)
print("#else", file=output)
print("constexpr uint32_t gHistogramKeyTable[] = {", file=output)
print("#endif", file=output)
for name, indexes in keys_table:
print("/* %s */ %s," % (name, ", ".join(map(str, indexes))), file=output)
print("};", file=output)
static_assert(output, "sizeof(gHistogramKeyTable) <= UINT16_MAX", "index overflow")
store_table_name = "gHistogramStoresTable"
print("\n#if defined(_MSC_VER) && !defined(__clang__)", file=output)
print("const uint32_t {}[] = {{".format(store_table_name), file=output)
print("#else", file=output)
print("constexpr uint32_t {}[] = {{".format(store_table_name), file=output)
print("#endif", file=output)
for name, indexes in store_table:
print("/* %s */ %s," % (name, ", ".join(map(str, indexes))), file=output)
print("};", file=output)
static_assert(
output, "sizeof(%s) <= UINT16_MAX" % store_table_name, "index overflow"
)
# 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,
}
target_os = buildconfig.substs["OS_TARGET"]
for histogram in histograms:
kind = histogram.kind()
if not histogram.record_on_os(target_os):
continue
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("#if defined(_MSC_VER) && !defined(__clang__)", file=output)
print("const int gHistogramBucketLowerBounds[] = {", file=output)
print("#else", file=output)
print("constexpr int gHistogramBucketLowerBounds[] = {", file=output)
print("#endif", 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.")
target_os = buildconfig.substs["OS_TARGET"]
print("#if defined(_MSC_VER) && !defined(__clang__)", file=output)
print("const int16_t gHistogramBucketLowerBoundIndex[] = {", file=output)
print("#else", file=output)
print("constexpr int16_t gHistogramBucketLowerBoundIndex[] = {", file=output)
print("#endif", file=output)
for histogram in histograms:
if histogram.record_on_os(target_os):
our_offset = ranges_offsets[tuple(histogram.ranges())]
print("%d," % our_offset, 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:])