bolt/utils/llvm-bolt-wrapper.py

   1 #!/usr/bin/env python3
   2 import argparse
   3 import subprocess
   4 from typing import *
   5 import tempfile
   6 import copy
   7 import os
   8 import shutil
   9 import sys
  10 import re
  11 import configparser
  12 from types import SimpleNamespace
  13 from textwrap import dedent
  14
  15 # USAGE:
  16 # 0. Prepare two BOLT build versions: base and compare.
  17 # 1. Create the config by invoking this script with required options.
  18 #    Save the config as `llvm-bolt-wrapper.ini` next to the script or
  19 #    in the testing directory.
  20 # In the base BOLT build directory:
  21 # 2. Rename `llvm-bolt` to `llvm-bolt.real`
  22 # 3. Create a symlink from this script to `llvm-bolt`
  23 # 4. Create `llvm-bolt-wrapper.ini` and fill it using the example below.
  24 #
  25 # This script will compare binaries produced by base and compare BOLT, and
  26 # report elapsed processing time and max RSS.
  27
  28 # read options from config file llvm-bolt-wrapper.ini in script CWD
  29 #
  30 # [config]
  31 # # mandatory
  32 # base_bolt = /full/path/to/llvm-bolt.real
  33 # cmp_bolt = /full/path/to/other/llvm-bolt
  34 # # optional, default to False
  35 # verbose
  36 # keep_tmp
  37 # no_minimize
  38 # run_sequentially
  39 # compare_output
  40 # skip_binary_cmp
  41 # # optional, defaults to timing.log in CWD
  42 # timing_file = timing1.log
  43
  44
  45 def read_cfg():
  46     src_dir = os.path.dirname(os.path.abspath(__file__))
  47     cfg = configparser.ConfigParser(allow_no_value=True)
  48     cfgs = cfg.read("llvm-bolt-wrapper.ini")
  49     if not cfgs:
  50         cfgs = cfg.read(os.path.join(src_dir, "llvm-bolt-wrapper.ini"))
  51     assert cfgs, f"llvm-bolt-wrapper.ini is not found in {os.getcwd()}"
  52
  53     def get_cfg(key):
  54         # if key is not present in config, assume False
  55         if key not in cfg["config"]:
  56             return False
  57         # if key is present, but has no value, assume True
  58         if not cfg["config"][key]:
  59             return True
  60         # if key has associated value, interpret the value
  61         return cfg["config"].getboolean(key)
  62
  63     d = {
  64         # BOLT binary locations
  65         "BASE_BOLT": cfg["config"]["base_bolt"],
  66         "CMP_BOLT": cfg["config"]["cmp_bolt"],
  67         # optional
  68         "VERBOSE": get_cfg("verbose"),
  69         "KEEP_TMP": get_cfg("keep_tmp"),
  70         "NO_MINIMIZE": get_cfg("no_minimize"),
  71         "RUN_SEQUENTIALLY": get_cfg("run_sequentially"),
  72         "COMPARE_OUTPUT": get_cfg("compare_output"),
  73         "SKIP_BINARY_CMP": get_cfg("skip_binary_cmp"),
  74         "TIMING_FILE": cfg["config"].get("timing_file", "timing.log"),
  75     }
  76     if d["VERBOSE"]:
  77         print(f"Using config {os.path.abspath(cfgs[0])}")
  78     return SimpleNamespace(**d)
  79
  80
  81 # perf2bolt mode
  82 PERF2BOLT_MODE = ["-aggregate-only", "-ignore-build-id"]
  83
  84 # boltdiff mode
  85 BOLTDIFF_MODE = ["-diff-only", "-o", "/dev/null"]
  86
  87 # options to suppress binary differences as much as possible
  88 MINIMIZE_DIFFS = ["-bolt-info=0"]
  89
  90 # bolt output options that need to be intercepted
  91 BOLT_OUTPUT_OPTS = {
  92     "-o": "BOLT output binary",
  93     "-w": "BOLT recorded profile",
  94 }
  95
  96 # regex patterns to exclude the line from log comparison
  97 SKIP_MATCH = [
  98     "BOLT-INFO: BOLT version",
  99     r"^Args: ",
 100     r"^BOLT-DEBUG:",
 101     r"BOLT-INFO:.*data.*output data",
 102     "WARNING: reading perf data directly",
 103 ]
 104
 105
 106 def run_cmd(cmd, out_f, cfg):
 107     if cfg.VERBOSE:
 108         print(" ".join(cmd))
 109     return subprocess.Popen(cmd, stdout=out_f, stderr=subprocess.STDOUT)
 110
 111
 112 def run_bolt(bolt_path, bolt_args, out_f, cfg):
 113     p2b = os.path.basename(sys.argv[0]) == "perf2bolt"  # perf2bolt mode
 114     bd = os.path.basename(sys.argv[0]) == "llvm-boltdiff"  # boltdiff mode
 115     cmd = ["/usr/bin/time", "-f", "%e %M", bolt_path] + bolt_args
 116     if p2b:
 117         # -ignore-build-id can occur at most once, hence remove it from cmd
 118         if "-ignore-build-id" in cmd:
 119             cmd.remove("-ignore-build-id")
 120         cmd += PERF2BOLT_MODE
 121     elif bd:
 122         cmd += BOLTDIFF_MODE
 123     elif not cfg.NO_MINIMIZE:
 124         cmd += MINIMIZE_DIFFS
 125     return run_cmd(cmd, out_f, cfg)
 126
 127
 128 def prepend_dash(args: Mapping[AnyStr, AnyStr]) -> Sequence[AnyStr]:
 129     """
 130     Accepts parsed arguments and returns flat list with dash prepended to
 131     the option.
 132     Example: Namespace(o='test.tmp') -> ['-o', 'test.tmp']
 133     """
 134     dashed = [("-" + key, value) for (key, value) in args.items()]
 135     flattened = list(sum(dashed, ()))
 136     return flattened
 137
 138
 139 def replace_cmp_path(tmp: AnyStr, args: Mapping[AnyStr, AnyStr]) -> Sequence[AnyStr]:
 140     """
 141     Keeps file names, but replaces the path to a temp folder.
 142     Example: Namespace(o='abc/test.tmp') -> Namespace(o='/tmp/tmpf9un/test.tmp')
 143     Except preserve /dev/null.
 144     """
 145     replace_path = (
 146         lambda x: os.path.join(tmp, os.path.basename(x))
 147         if x != "/dev/null"
 148         else "/dev/null"
 149     )
 150     new_args = {key: replace_path(value) for key, value in args.items()}
 151     return prepend_dash(new_args)
 152
 153
 154 def preprocess_args(args: argparse.Namespace) -> Mapping[AnyStr, AnyStr]:
 155     """
 156     Drop options that weren't parsed (e.g. -w), convert to a dict
 157     """
 158     return {key: value for key, value in vars(args).items() if value}
 159
 160
 161 def write_to(txt, filename, mode="w"):
 162     with open(filename, mode) as f:
 163         f.write(txt)
 164
 165
 166 def wait(proc, fdesc):
 167     proc.wait()
 168     fdesc.close()
 169     return open(fdesc.name)
 170
 171
 172 def compare_logs(main, cmp, skip_begin=0, skip_end=0, str_input=True):
 173     """
 174     Compares logs but allows for certain lines to be excluded from comparison.
 175     If str_input is True (default), the input it assumed to be a string,
 176     which is split into lines. Otherwise the input is assumed to be a file.
 177     Returns None on success, mismatch otherwise.
 178     """
 179     main_inp = main.splitlines() if str_input else main.readlines()
 180     cmp_inp = cmp.splitlines() if str_input else cmp.readlines()
 181     # rewind logs after consumption
 182     if not str_input:
 183         main.seek(0)
 184         cmp.seek(0)
 185     for lhs, rhs in list(zip(main_inp, cmp_inp))[skip_begin : -skip_end or None]:
 186         if lhs != rhs:
 187             # check skip patterns
 188             for skip in SKIP_MATCH:
 189                 # both lines must contain the pattern
 190                 if re.search(skip, lhs) and re.search(skip, rhs):
 191                     break
 192             # otherwise return mismatching lines
 193             else:
 194                 return (lhs, rhs)
 195     return None
 196
 197
 198 def fmt_cmp(cmp_tuple):
 199     if not cmp_tuple:
 200         return ""
 201     return f"main:\n{cmp_tuple[0]}\ncmp:\n{cmp_tuple[1]}\n"
 202
 203
 204 def compare_with(lhs, rhs, cmd, skip_begin=0, skip_end=0):
 205     """
 206     Runs cmd on both lhs and rhs and compares stdout.
 207     Returns tuple (mismatch, lhs_stdout):
 208         - if stdout matches between two files, mismatch is None,
 209         - otherwise mismatch is a tuple of mismatching lines.
 210     """
 211     run = lambda binary: subprocess.run(
 212         cmd.split() + [binary], text=True, check=True, capture_output=True
 213     ).stdout
 214     run_lhs = run(lhs)
 215     run_rhs = run(rhs)
 216     cmp = compare_logs(run_lhs, run_rhs, skip_begin, skip_end)
 217     return cmp, run_lhs
 218
 219
 220 def parse_cmp_offset(cmp_out):
 221     """
 222     Extracts byte number from cmp output:
 223     file1 file2 differ: byte X, line Y
 224     """
 225     # NOTE: cmp counts bytes starting from 1!
 226     return int(re.search(r"byte (\d+),", cmp_out).groups()[0]) - 1
 227
 228
 229 def report_real_time(binary, main_err, cmp_err, cfg):
 230     """
 231     Extracts real time from stderr and appends it to TIMING FILE it as csv:
 232     "output binary; base bolt; cmp bolt"
 233     """
 234
 235     def get_real_from_stderr(logline):
 236         return "; ".join(logline.split())
 237
 238     for line in main_err:
 239         pass
 240     main = get_real_from_stderr(line)
 241     for line in cmp_err:
 242         pass
 243     cmp = get_real_from_stderr(line)
 244     write_to(f"{binary}; {main}; {cmp}\n", cfg.TIMING_FILE, "a")
 245     # rewind logs after consumption
 246     main_err.seek(0)
 247     cmp_err.seek(0)
 248
 249
 250 def clean_exit(tmp, out, exitcode, cfg):
 251     # temp files are only cleaned on success
 252     if not cfg.KEEP_TMP:
 253         shutil.rmtree(tmp)
 254
 255     # report stdout and stderr from the main process
 256     shutil.copyfileobj(out, sys.stdout)
 257     sys.exit(exitcode)
 258
 259
 260 def find_section(offset, readelf_hdr):
 261     hdr = readelf_hdr.split("\n")
 262     section = None
 263     # extract sections table (parse objdump -hw output)
 264     for line in hdr[5:-1]:
 265         cols = line.strip().split()
 266         # extract section offset
 267         file_offset = int(cols[5], 16)
 268         # section size
 269         size = int(cols[2], 16)
 270         if offset >= file_offset and offset < file_offset + size:
 271             if sys.stdout.isatty():  # terminal supports colors
 272                 print(f"\033[1m{line}\033[0m")
 273             else:
 274                 print(f">{line}")
 275             section = cols[1]
 276         else:
 277             print(line)
 278     return section
 279
 280
 281 def main_config_generator():
 282     parser = argparse.ArgumentParser()
 283     parser.add_argument("base_bolt", help="Full path to base llvm-bolt binary")
 284     parser.add_argument("cmp_bolt", help="Full path to cmp llvm-bolt binary")
 285     parser.add_argument(
 286         "--verbose",
 287         action="store_true",
 288         help="Print subprocess invocation cmdline (default False)",
 289     )
 290     parser.add_argument(
 291         "--keep_tmp",
 292         action="store_true",
 293         help="Preserve tmp folder on a clean exit "
 294         "(tmp directory is preserved on crash by default)",
 295     )
 296     parser.add_argument(
 297         "--no_minimize",
 298         action="store_true",
 299         help=f"Do not add `{MINIMIZE_DIFFS}` that is used "
 300         "by default to reduce binary differences",
 301     )
 302     parser.add_argument(
 303         "--run_sequentially",
 304         action="store_true",
 305         help="Run both binaries sequentially (default "
 306         "in parallel). Use for timing comparison",
 307     )
 308     parser.add_argument(
 309         "--compare_output",
 310         action="store_true",
 311         help="Compare bolt stdout/stderr (disabled by default)",
 312     )
 313     parser.add_argument(
 314         "--skip_binary_cmp", action="store_true", help="Disable output comparison"
 315     )
 316     parser.add_argument(
 317         "--timing_file",
 318         help="Override path to timing log " "file (default `timing.log` in CWD)",
 319     )
 320     args = parser.parse_args()
 321
 322     print(
 323         dedent(
 324             f"""\
 325     [config]
 326     # mandatory
 327     base_bolt = {args.base_bolt}
 328     cmp_bolt = {args.cmp_bolt}"""
 329         )
 330     )
 331     del args.base_bolt
 332     del args.cmp_bolt
 333     d = vars(args)
 334     if any(d.values()):
 335         print("# optional")
 336         for key, value in d.items():
 337             if value:
 338                 print(key)
 339
 340
 341 def main():
 342     cfg = read_cfg()
 343     # intercept output arguments
 344     parser = argparse.ArgumentParser(add_help=False)
 345     for option, help in BOLT_OUTPUT_OPTS.items():
 346         parser.add_argument(option, help=help)
 347     args, unknownargs = parser.parse_known_args()
 348     args = preprocess_args(args)
 349     cmp_args = copy.deepcopy(args)
 350     tmp = tempfile.mkdtemp()
 351     cmp_args = replace_cmp_path(tmp, cmp_args)
 352
 353     # reconstruct output arguments: prepend dash
 354     args = prepend_dash(args)
 355
 356     # run both BOLT binaries
 357     main_f = open(os.path.join(tmp, "main_bolt.stdout"), "w")
 358     cmp_f = open(os.path.join(tmp, "cmp_bolt.stdout"), "w")
 359     main_bolt = run_bolt(cfg.BASE_BOLT, unknownargs + args, main_f, cfg)
 360     if cfg.RUN_SEQUENTIALLY:
 361         main_out = wait(main_bolt, main_f)
 362         cmp_bolt = run_bolt(cfg.CMP_BOLT, unknownargs + cmp_args, cmp_f, cfg)
 363     else:
 364         cmp_bolt = run_bolt(cfg.CMP_BOLT, unknownargs + cmp_args, cmp_f, cfg)
 365         main_out = wait(main_bolt, main_f)
 366     cmp_out = wait(cmp_bolt, cmp_f)
 367
 368     # check exit code
 369     if main_bolt.returncode != cmp_bolt.returncode:
 370         print(tmp)
 371         exit("exitcode mismatch")
 372
 373     # don't compare output upon unsuccessful exit
 374     if main_bolt.returncode != 0:
 375         cfg.SKIP_BINARY_CMP = True
 376
 377     # compare logs, skip_end=1 skips the line with time
 378     out = (
 379         compare_logs(main_out, cmp_out, skip_end=1, str_input=False)
 380         if cfg.COMPARE_OUTPUT
 381         else None
 382     )
 383     if out:
 384         print(tmp)
 385         print(fmt_cmp(out))
 386         write_to(fmt_cmp(out), os.path.join(tmp, "summary.txt"))
 387         exit("logs mismatch")
 388
 389     if os.path.basename(sys.argv[0]) == "llvm-boltdiff":  # boltdiff mode
 390         # no output binary to compare, so just exit
 391         clean_exit(tmp, main_out, main_bolt.returncode, cfg)
 392
 393     # compare binaries (using cmp)
 394     main_binary = args[args.index("-o") + 1]
 395     cmp_binary = cmp_args[cmp_args.index("-o") + 1]
 396     if main_binary == "/dev/null":
 397         assert cmp_binary == "/dev/null"
 398         cfg.SKIP_BINARY_CMP = True
 399
 400     # report binary timing as csv: output binary; base bolt real; cmp bolt real
 401     report_real_time(main_binary, main_out, cmp_out, cfg)
 402
 403     if not cfg.SKIP_BINARY_CMP:
 404         # check if files exist
 405         main_exists = os.path.exists(main_binary)
 406         cmp_exists = os.path.exists(cmp_binary)
 407         if main_exists and cmp_exists:
 408             # proceed to comparison
 409             pass
 410         elif not main_exists and not cmp_exists:
 411             # both don't exist, assume it's intended, skip comparison
 412             clean_exit(tmp, main_out, main_bolt.returncode, cfg)
 413         elif main_exists:
 414             assert not cmp_exists
 415             exit(f"{cmp_binary} doesn't exist")
 416         else:
 417             assert not main_exists
 418             exit(f"{main_binary} doesn't exist")
 419
 420         cmp_proc = subprocess.run(
 421             ["cmp", "-b", main_binary, cmp_binary], capture_output=True, text=True
 422         )
 423         if cmp_proc.returncode:
 424             # check if output is an ELF file (magic bytes)
 425             with open(main_binary, "rb") as f:
 426                 magic = f.read(4)
 427                 if magic != b"\x7fELF":
 428                     exit("output mismatch")
 429             # check if ELF headers match
 430             mismatch, _ = compare_with(main_binary, cmp_binary, "readelf -We")
 431             if mismatch:
 432                 print(fmt_cmp(mismatch))
 433                 write_to(fmt_cmp(mismatch), os.path.join(tmp, "headers.txt"))
 434                 exit("headers mismatch")
 435             # if headers match, compare sections (skip line with filename)
 436             mismatch, hdr = compare_with(
 437                 main_binary, cmp_binary, "objdump -hw", skip_begin=2
 438             )
 439             assert not mismatch
 440             # check which section has the first mismatch
 441             mismatch_offset = parse_cmp_offset(cmp_proc.stdout)
 442             section = find_section(mismatch_offset, hdr)
 443             exit(f"binary mismatch @{hex(mismatch_offset)} ({section})")
 444
 445     clean_exit(tmp, main_out, main_bolt.returncode, cfg)
 446
 447
 448 if __name__ == "__main__":
 449     # config generator mode if the script is launched as is
 450     if os.path.basename(__file__) == "llvm-bolt-wrapper.py":
 451         main_config_generator()
 452     else:
 453         # llvm-bolt interceptor mode otherwise
 454         main()