#!/usr/bin/env python3
import argparse
import subprocess
from typing import *
import tempfile
import copy
import os
import shutil
import sys
import re
import configparser
from types import SimpleNamespace
from textwrap import dedent
# USAGE:
# 0. Prepare two BOLT build versions: base and compare.
# 1. Create the config by invoking this script with required options.
# Save the config as `llvm-bolt-wrapper.ini` next to the script or
# in the testing directory.
# In the base BOLT build directory:
# 2. Rename `llvm-bolt` to `llvm-bolt.real`
# 3. Create a symlink from this script to `llvm-bolt`
# 4. Create `llvm-bolt-wrapper.ini` and fill it using the example below.
#
# This script will compare binaries produced by base and compare BOLT, and
# report elapsed processing time and max RSS.
# read options from config file llvm-bolt-wrapper.ini in script CWD
#
# [config]
# # mandatory
# base_bolt = /full/path/to/llvm-bolt.real
# cmp_bolt = /full/path/to/other/llvm-bolt
# # optional, default to False
# verbose
# keep_tmp
# no_minimize
# run_sequentially
# compare_output
# skip_binary_cmp
# # optional, defaults to timing.log in CWD
# timing_file = timing1.log
def read_cfg():
src_dir = os.path.dirname(os.path.abspath(__file__))
cfg = configparser.ConfigParser(allow_no_value=True)
cfgs = cfg.read("llvm-bolt-wrapper.ini")
if not cfgs:
cfgs = cfg.read(os.path.join(src_dir, "llvm-bolt-wrapper.ini"))
assert cfgs, f"llvm-bolt-wrapper.ini is not found in {os.getcwd()}"
def get_cfg(key):
# if key is not present in config, assume False
if key not in cfg["config"]:
return False
# if key is present, but has no value, assume True
if not cfg["config"][key]:
return True
# if key has associated value, interpret the value
return cfg["config"].getboolean(key)
d = {
# BOLT binary locations
"BASE_BOLT": cfg["config"]["base_bolt"],
"CMP_BOLT": cfg["config"]["cmp_bolt"],
# optional
"VERBOSE": get_cfg("verbose"),
"KEEP_TMP": get_cfg("keep_tmp"),
"NO_MINIMIZE": get_cfg("no_minimize"),
"RUN_SEQUENTIALLY": get_cfg("run_sequentially"),
"COMPARE_OUTPUT": get_cfg("compare_output"),
"SKIP_BINARY_CMP": get_cfg("skip_binary_cmp"),
"TIMING_FILE": cfg["config"].get("timing_file", "timing.log"),
}
if d["VERBOSE"]:
print(f"Using config {os.path.abspath(cfgs[0])}")
return SimpleNamespace(**d)
# perf2bolt mode
PERF2BOLT_MODE = ["-aggregate-only", "-ignore-build-id"]
# boltdiff mode
BOLTDIFF_MODE = ["-diff-only", "-o", "/dev/null"]
# options to suppress binary differences as much as possible
MINIMIZE_DIFFS = ["-bolt-info=0"]
# bolt output options that need to be intercepted
BOLT_OUTPUT_OPTS = {
"-o": "BOLT output binary",
"-w": "BOLT recorded profile",
}
# regex patterns to exclude the line from log comparison
SKIP_MATCH = [
"BOLT-INFO: BOLT version",
r"^Args: ",
r"^BOLT-DEBUG:",
r"BOLT-INFO:.*data.*output data",
"WARNING: reading perf data directly",
]
def run_cmd(cmd, out_f, cfg):
if cfg.VERBOSE:
print(" ".join(cmd))
return subprocess.Popen(cmd, stdout=out_f, stderr=subprocess.STDOUT)
def run_bolt(bolt_path, bolt_args, out_f, cfg):
p2b = os.path.basename(sys.argv[0]) == "perf2bolt" # perf2bolt mode
bd = os.path.basename(sys.argv[0]) == "llvm-boltdiff" # boltdiff mode
cmd = ["/usr/bin/time", "-f", "%e %M", bolt_path] + bolt_args
if p2b:
# -ignore-build-id can occur at most once, hence remove it from cmd
if "-ignore-build-id" in cmd:
cmd.remove("-ignore-build-id")
cmd += PERF2BOLT_MODE
elif bd:
cmd += BOLTDIFF_MODE
elif not cfg.NO_MINIMIZE:
cmd += MINIMIZE_DIFFS
return run_cmd(cmd, out_f, cfg)
def prepend_dash(args: Mapping[AnyStr, AnyStr]) -> Sequence[AnyStr]:
"""
Accepts parsed arguments and returns flat list with dash prepended to
the option.
Example: Namespace(o='test.tmp') -> ['-o', 'test.tmp']
"""
dashed = [("-" + key, value) for (key, value) in args.items()]
flattened = list(sum(dashed, ()))
return flattened
def replace_cmp_path(tmp: AnyStr, args: Mapping[AnyStr, AnyStr]) -> Sequence[AnyStr]:
"""
Keeps file names, but replaces the path to a temp folder.
Example: Namespace(o='abc/test.tmp') -> Namespace(o='/tmp/tmpf9un/test.tmp')
Except preserve /dev/null.
"""
replace_path = (
lambda x: os.path.join(tmp, os.path.basename(x))
if x != "/dev/null"
else "/dev/null"
)
new_args = {key: replace_path(value) for key, value in args.items()}
return prepend_dash(new_args)
def preprocess_args(args: argparse.Namespace) -> Mapping[AnyStr, AnyStr]:
"""
Drop options that weren't parsed (e.g. -w), convert to a dict
"""
return {key: value for key, value in vars(args).items() if value}
def write_to(txt, filename, mode="w"):
with open(filename, mode) as f:
f.write(txt)
def wait(proc, fdesc):
proc.wait()
fdesc.close()
return open(fdesc.name)
def compare_logs(main, cmp, skip_begin=0, skip_end=0, str_input=True):
"""
Compares logs but allows for certain lines to be excluded from comparison.
If str_input is True (default), the input it assumed to be a string,
which is split into lines. Otherwise the input is assumed to be a file.
Returns None on success, mismatch otherwise.
"""
main_inp = main.splitlines() if str_input else main.readlines()
cmp_inp = cmp.splitlines() if str_input else cmp.readlines()
# rewind logs after consumption
if not str_input:
main.seek(0)
cmp.seek(0)
for lhs, rhs in list(zip(main_inp, cmp_inp))[skip_begin : -skip_end or None]:
if lhs != rhs:
# check skip patterns
for skip in SKIP_MATCH:
# both lines must contain the pattern
if re.search(skip, lhs) and re.search(skip, rhs):
break
# otherwise return mismatching lines
else:
return (lhs, rhs)
return None
def fmt_cmp(cmp_tuple):
if not cmp_tuple:
return ""
return f"main:\n{cmp_tuple[0]}\ncmp:\n{cmp_tuple[1]}\n"
def compare_with(lhs, rhs, cmd, skip_begin=0, skip_end=0):
"""
Runs cmd on both lhs and rhs and compares stdout.
Returns tuple (mismatch, lhs_stdout):
- if stdout matches between two files, mismatch is None,
- otherwise mismatch is a tuple of mismatching lines.
"""
run = lambda binary: subprocess.run(
cmd.split() + [binary], text=True, check=True, capture_output=True
).stdout
run_lhs = run(lhs)
run_rhs = run(rhs)
cmp = compare_logs(run_lhs, run_rhs, skip_begin, skip_end)
return cmp, run_lhs
def parse_cmp_offset(cmp_out):
"""
Extracts byte number from cmp output:
file1 file2 differ: byte X, line Y
"""
# NOTE: cmp counts bytes starting from 1!
return int(re.search(r"byte (\d+),", cmp_out).groups()[0]) - 1
def report_real_time(binary, main_err, cmp_err, cfg):
"""
Extracts real time from stderr and appends it to TIMING FILE it as csv:
"output binary; base bolt; cmp bolt"
"""
def get_real_from_stderr(logline):
return "; ".join(logline.split())
for line in main_err:
pass
main = get_real_from_stderr(line)
for line in cmp_err:
pass
cmp = get_real_from_stderr(line)
write_to(f"{binary}; {main}; {cmp}\n", cfg.TIMING_FILE, "a")
# rewind logs after consumption
main_err.seek(0)
cmp_err.seek(0)
def clean_exit(tmp, out, exitcode, cfg):
# temp files are only cleaned on success
if not cfg.KEEP_TMP:
shutil.rmtree(tmp)
# report stdout and stderr from the main process
shutil.copyfileobj(out, sys.stdout)
sys.exit(exitcode)
def find_section(offset, readelf_hdr):
hdr = readelf_hdr.split("\n")
section = None
# extract sections table (parse objdump -hw output)
for line in hdr[5:-1]:
cols = line.strip().split()
# extract section offset
file_offset = int(cols[5], 16)
# section size
size = int(cols[2], 16)
if offset >= file_offset and offset < file_offset + size:
if sys.stdout.isatty(): # terminal supports colors
print(f"\033[1m{line}\033[0m")
else:
print(f">{line}")
section = cols[1]
else:
print(line)
return section
def main_config_generator():
parser = argparse.ArgumentParser()
parser.add_argument("base_bolt", help="Full path to base llvm-bolt binary")
parser.add_argument("cmp_bolt", help="Full path to cmp llvm-bolt binary")
parser.add_argument(
"--verbose",
action="store_true",
help="Print subprocess invocation cmdline (default False)",
)
parser.add_argument(
"--keep_tmp",
action="store_true",
help="Preserve tmp folder on a clean exit "
"(tmp directory is preserved on crash by default)",
)
parser.add_argument(
"--no_minimize",
action="store_true",
help=f"Do not add `{MINIMIZE_DIFFS}` that is used "
"by default to reduce binary differences",
)
parser.add_argument(
"--run_sequentially",
action="store_true",
help="Run both binaries sequentially (default "
"in parallel). Use for timing comparison",
)
parser.add_argument(
"--compare_output",
action="store_true",
help="Compare bolt stdout/stderr (disabled by default)",
)
parser.add_argument(
"--skip_binary_cmp", action="store_true", help="Disable output comparison"
)
parser.add_argument(
"--timing_file",
help="Override path to timing log " "file (default `timing.log` in CWD)",
)
args = parser.parse_args()
print(
dedent(
f"""\
[config]
# mandatory
base_bolt = {args.base_bolt}
cmp_bolt = {args.cmp_bolt}"""
)
)
del args.base_bolt
del args.cmp_bolt
d = vars(args)
if any(d.values()):
print("# optional")
for key, value in d.items():
if value:
print(key)
def main():
cfg = read_cfg()
# intercept output arguments
parser = argparse.ArgumentParser(add_help=False)
for option, help in BOLT_OUTPUT_OPTS.items():
parser.add_argument(option, help=help)
args, unknownargs = parser.parse_known_args()
args = preprocess_args(args)
cmp_args = copy.deepcopy(args)
tmp = tempfile.mkdtemp()
cmp_args = replace_cmp_path(tmp, cmp_args)
# reconstruct output arguments: prepend dash
args = prepend_dash(args)
# run both BOLT binaries
main_f = open(os.path.join(tmp, "main_bolt.stdout"), "w")
cmp_f = open(os.path.join(tmp, "cmp_bolt.stdout"), "w")
main_bolt = run_bolt(cfg.BASE_BOLT, unknownargs + args, main_f, cfg)
if cfg.RUN_SEQUENTIALLY:
main_out = wait(main_bolt, main_f)
cmp_bolt = run_bolt(cfg.CMP_BOLT, unknownargs + cmp_args, cmp_f, cfg)
else:
cmp_bolt = run_bolt(cfg.CMP_BOLT, unknownargs + cmp_args, cmp_f, cfg)
main_out = wait(main_bolt, main_f)
cmp_out = wait(cmp_bolt, cmp_f)
# check exit code
if main_bolt.returncode != cmp_bolt.returncode:
print(tmp)
exit("exitcode mismatch")
# don't compare output upon unsuccessful exit
if main_bolt.returncode != 0:
cfg.SKIP_BINARY_CMP = True
# compare logs, skip_end=1 skips the line with time
out = (
compare_logs(main_out, cmp_out, skip_end=1, str_input=False)
if cfg.COMPARE_OUTPUT
else None
)
if out:
print(tmp)
print(fmt_cmp(out))
write_to(fmt_cmp(out), os.path.join(tmp, "summary.txt"))
exit("logs mismatch")
if os.path.basename(sys.argv[0]) == "llvm-boltdiff": # boltdiff mode
# no output binary to compare, so just exit
clean_exit(tmp, main_out, main_bolt.returncode, cfg)
# compare binaries (using cmp)
main_binary = args[args.index("-o") + 1]
cmp_binary = cmp_args[cmp_args.index("-o") + 1]
if main_binary == "/dev/null":
assert cmp_binary == "/dev/null"
cfg.SKIP_BINARY_CMP = True
# report binary timing as csv: output binary; base bolt real; cmp bolt real
report_real_time(main_binary, main_out, cmp_out, cfg)
if not cfg.SKIP_BINARY_CMP:
# check if files exist
main_exists = os.path.exists(main_binary)
cmp_exists = os.path.exists(cmp_binary)
if main_exists and cmp_exists:
# proceed to comparison
pass
elif not main_exists and not cmp_exists:
# both don't exist, assume it's intended, skip comparison
clean_exit(tmp, main_out, main_bolt.returncode, cfg)
elif main_exists:
assert not cmp_exists
exit(f"{cmp_binary} doesn't exist")
else:
assert not main_exists
exit(f"{main_binary} doesn't exist")
cmp_proc = subprocess.run(
["cmp", "-b", main_binary, cmp_binary], capture_output=True, text=True
)
if cmp_proc.returncode:
# check if output is an ELF file (magic bytes)
with open(main_binary, "rb") as f:
magic = f.read(4)
if magic != b"\x7fELF":
exit("output mismatch")
# check if ELF headers match
mismatch, _ = compare_with(main_binary, cmp_binary, "readelf -We")
if mismatch:
print(fmt_cmp(mismatch))
write_to(fmt_cmp(mismatch), os.path.join(tmp, "headers.txt"))
exit("headers mismatch")
# if headers match, compare sections (skip line with filename)
mismatch, hdr = compare_with(
main_binary, cmp_binary, "objdump -hw", skip_begin=2
)
assert not mismatch
# check which section has the first mismatch
mismatch_offset = parse_cmp_offset(cmp_proc.stdout)
section = find_section(mismatch_offset, hdr)
exit(f"binary mismatch @{hex(mismatch_offset)} ({section})")
clean_exit(tmp, main_out, main_bolt.returncode, cfg)
if __name__ == "__main__":
# config generator mode if the script is launched as is
if os.path.basename(__file__) == "llvm-bolt-wrapper.py":
main_config_generator()
else:
# llvm-bolt interceptor mode otherwise
main()
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