config/check_spidermonkey_style.py

   1 # vim: set ts=8 sts=4 et sw=4 tw=99:
   2 # This Source Code Form is subject to the terms of the Mozilla Public
   3 # License, v. 2.0. If a copy of the MPL was not distributed with this
   4 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
   5
   6 # ----------------------------------------------------------------------------
   7 # This script checks various aspects of SpiderMonkey code style.  The current checks are as
   8 # follows.
   9 #
  10 # We check the following things in headers.
  11 #
  12 # - No cyclic dependencies.
  13 #
  14 # - No normal header should #include a inlines.h/-inl.h file.
  15 #
  16 # - #ifndef wrappers should have the right form. (XXX: not yet implemented)
  17 #   - Every header file should have one.
  18 #   - The guard name used should be appropriate for the filename.
  19 #
  20 # We check the following things in all files.
  21 #
  22 # - #includes should have full paths, e.g. "jit/Ion.h", not "Ion.h".
  23 #
  24 # - #includes should use the appropriate form for system headers (<...>) and
  25 #   local headers ("...").
  26 #
  27 # - #includes should be ordered correctly.
  28 #   - Each one should be in the correct section.
  29 #   - Alphabetical order should be used within sections.
  30 #   - Sections should be in the right order.
  31 #   Note that the presence of #if/#endif blocks complicates things, to the
  32 #   point that it's not always clear where a conditionally-compiled #include
  33 #   statement should go, even to a human.  Therefore, we check the #include
  34 #   statements within each #if/#endif block (including nested ones) in
  35 #   isolation, but don't try to do any order checking between such blocks.
  36 # ----------------------------------------------------------------------------
  37
  38 import difflib
  39 import os
  40 import re
  41 import sys
  42
  43 # We don't bother checking files in these directories, because they're (a) auxiliary or (b)
  44 # imported code that doesn't follow our coding style.
  45 ignored_js_src_dirs = [
  46     "js/src/config/",  # auxiliary stuff
  47     "js/src/ctypes/libffi/",  # imported code
  48     "js/src/devtools/",  # auxiliary stuff
  49     "js/src/editline/",  # imported code
  50     "js/src/gdb/",  # auxiliary stuff
  51     "js/src/vtune/",  # imported code
  52     "js/src/zydis/",  # imported code
  53 ]
  54
  55 # We ignore #includes of these files, because they don't follow the usual rules.
  56 included_inclnames_to_ignore = set(
  57     [
  58         "ffi.h",  # generated in ctypes/libffi/
  59         "devtools/Instruments.h",  # we ignore devtools/ in general
  60         "double-conversion/double-conversion.h",  # strange MFBT case
  61         "javascript-trace.h",  # generated in $OBJDIR if HAVE_DTRACE is defined
  62         "frontend/ReservedWordsGenerated.h",  # generated in $OBJDIR
  63         "frontend/smoosh_generated.h",  # generated in $OBJDIR
  64         "gc/StatsPhasesGenerated.h",  # generated in $OBJDIR
  65         "gc/StatsPhasesGenerated.inc",  # generated in $OBJDIR
  66         "jit/AtomicOperationsGenerated.h",  # generated in $OBJDIR
  67         "jit/CacheIROpsGenerated.h",  # generated in $OBJDIR
  68         "jit/LIROpsGenerated.h",  # generated in $OBJDIR
  69         "jit/MIROpsGenerated.h",  # generated in $OBJDIR
  70         "js/ProfilingCategoryList.h",  # comes from mozglue/baseprofiler
  71         "jscustomallocator.h",  # provided by embedders;  allowed to be missing
  72         "js-config.h",  # generated in $OBJDIR
  73         "fdlibm.h",  # fdlibm
  74         "FuzzerDefs.h",  # included without a path
  75         "FuzzingInterface.h",  # included without a path
  76         "mozmemory.h",  # included without a path
  77         "pratom.h",  # NSPR
  78         "prcvar.h",  # NSPR
  79         "prerror.h",  # NSPR
  80         "prinit.h",  # NSPR
  81         "prio.h",  # NSPR
  82         "private/pprio.h",  # NSPR
  83         "prlink.h",  # NSPR
  84         "prlock.h",  # NSPR
  85         "prprf.h",  # NSPR
  86         "prthread.h",  # NSPR
  87         "prtypes.h",  # NSPR
  88         "selfhosted.out.h",  # generated in $OBJDIR
  89         "shellmoduleloader.out.h",  # generated in $OBJDIR
  90         "unicode/locid.h",  # ICU
  91         "unicode/uchar.h",  # ICU
  92         "unicode/uniset.h",  # ICU
  93         "unicode/unistr.h",  # ICU
  94         "unicode/utypes.h",  # ICU
  95         "vtune/VTuneWrapper.h",  # VTune
  96         "wasm/WasmIntrinsicGenerated.h",  # generated in $OBJDIR"
  97         "zydis/ZydisAPI.h",  # Zydis
  98     ]
  99 )
 100
 101 deprecated_inclnames = {
 102     "mozilla/Unused.h": "Use [[nodiscard]] and (void)expr casts instead.",
 103 }
 104
 105 # JSAPI functions should be included through headers from js/public instead of
 106 # using the old, catch-all jsapi.h file.
 107 deprecated_inclnames_in_header = {
 108     "jsapi.h": "Prefer including headers from js/public.",
 109 }
 110
 111 # Temporary exclusions for files which still need to include jsapi.h.
 112 deprecated_inclnames_in_header_excludes = {
 113     "js/src/vm/Compartment-inl.h",  # for JS::InformalValueTypeName
 114     "js/src/jsapi-tests/tests.h",  # for JS_ValueToSource
 115 }
 116
 117 # These files have additional constraints on where they are #included, so we
 118 # ignore #includes of them when checking #include ordering.
 119 oddly_ordered_inclnames = set(
 120     [
 121         "ctypes/typedefs.h",  # Included multiple times in the body of ctypes/CTypes.h
 122         # Included in the body of frontend/TokenStream.h
 123         "frontend/ReservedWordsGenerated.h",
 124         "gc/StatsPhasesGenerated.h",  # Included in the body of gc/Statistics.h
 125         "gc/StatsPhasesGenerated.inc",  # Included in the body of gc/Statistics.cpp
 126         "psapi.h",  # Must be included after "util/WindowsWrapper.h" on Windows
 127         "machine/endian.h",  # Must be included after <sys/types.h> on BSD
 128         "process.h",  # Windows-specific
 129         "winbase.h",  # Must precede other system headers(?)
 130         "windef.h",  # Must precede other system headers(?)
 131         "windows.h",  # Must precede other system headers(?)
 132     ]
 133 )
 134
 135 # The files in tests/style/ contain code that fails this checking in various
 136 # ways.  Here is the output we expect.  If the actual output differs from
 137 # this, one of the following must have happened.
 138 # - New SpiderMonkey code violates one of the checked rules.
 139 # - The tests/style/ files have changed without expected_output being changed
 140 #   accordingly.
 141 # - This script has been broken somehow.
 142 #
 143 expected_output = """\
 144 js/src/tests/style/BadIncludes.h:3: error:
 145     the file includes itself
 146
 147 js/src/tests/style/BadIncludes.h:6: error:
 148     "BadIncludes2.h" is included using the wrong path;
 149     did you forget a prefix, or is the file not yet committed?
 150
 151 js/src/tests/style/BadIncludes.h:8: error:
 152     <tests/style/BadIncludes2.h> should be included using
 153     the #include "..." form
 154
 155 js/src/tests/style/BadIncludes.h:10: error:
 156     "stdio.h" is included using the wrong path;
 157     did you forget a prefix, or is the file not yet committed?
 158
 159 js/src/tests/style/BadIncludes.h:12: error:
 160     "mozilla/Unused.h" is deprecated: Use [[nodiscard]] and (void)expr casts instead.
 161
 162 js/src/tests/style/BadIncludes2.h:1: error:
 163     vanilla header includes an inline-header file "tests/style/BadIncludes2-inl.h"
 164
 165 js/src/tests/style/BadIncludesOrder-inl.h:5:6: error:
 166     "vm/JSScript-inl.h" should be included after "vm/Interpreter-inl.h"
 167
 168 js/src/tests/style/BadIncludesOrder-inl.h:6:7: error:
 169     "vm/Interpreter-inl.h" should be included after "js/Value.h"
 170
 171 js/src/tests/style/BadIncludesOrder-inl.h:7:8: error:
 172     "js/Value.h" should be included after "ds/LifoAlloc.h"
 173
 174 js/src/tests/style/BadIncludesOrder-inl.h:9: error:
 175     "jsapi.h" is deprecated: Prefer including headers from js/public.
 176
 177 js/src/tests/style/BadIncludesOrder-inl.h:8:9: error:
 178     "ds/LifoAlloc.h" should be included after "jsapi.h"
 179
 180 js/src/tests/style/BadIncludesOrder-inl.h:9:10: error:
 181     "jsapi.h" should be included after <stdio.h>
 182
 183 js/src/tests/style/BadIncludesOrder-inl.h:10:11: error:
 184     <stdio.h> should be included after "mozilla/HashFunctions.h"
 185
 186 js/src/tests/style/BadIncludesOrder-inl.h:20: error:
 187     "jsapi.h" is deprecated: Prefer including headers from js/public.
 188
 189 js/src/tests/style/BadIncludesOrder-inl.h:28:29: error:
 190     "vm/JSScript.h" should be included after "vm/JSFunction.h"
 191
 192 (multiple files): error:
 193     header files form one or more cycles
 194
 195    tests/style/HeaderCycleA1.h
 196    -> tests/style/HeaderCycleA2.h
 197       -> tests/style/HeaderCycleA3.h
 198          -> tests/style/HeaderCycleA1.h
 199
 200    tests/style/HeaderCycleB1-inl.h
 201    -> tests/style/HeaderCycleB2-inl.h
 202       -> tests/style/HeaderCycleB3-inl.h
 203          -> tests/style/HeaderCycleB4-inl.h
 204             -> tests/style/HeaderCycleB1-inl.h
 205             -> tests/style/jsheadercycleB5inlines.h
 206                -> tests/style/HeaderCycleB1-inl.h
 207       -> tests/style/HeaderCycleB4-inl.h
 208
 209 """.splitlines(
 210     True
 211 )
 212
 213 actual_output = []
 214
 215
 216 def out(*lines):
 217     for line in lines:
 218         actual_output.append(line + "\n")
 219
 220
 221 def error(filename, linenum, *lines):
 222     location = filename
 223     if linenum is not None:
 224         location += ":" + str(linenum)
 225     out(location + ": error:")
 226     for line in lines:
 227         out("    " + line)
 228     out("")
 229
 230
 231 class FileKind(object):
 232     C = 1
 233     CPP = 2
 234     INL_H = 3
 235     H = 4
 236     TBL = 5
 237     MSG = 6
 238
 239     @staticmethod
 240     def get(filename):
 241         if filename.endswith(".c"):
 242             return FileKind.C
 243
 244         if filename.endswith(".cpp"):
 245             return FileKind.CPP
 246
 247         if filename.endswith(("inlines.h", "-inl.h")):
 248             return FileKind.INL_H
 249
 250         if filename.endswith(".h"):
 251             return FileKind.H
 252
 253         if filename.endswith(".tbl"):
 254             return FileKind.TBL
 255
 256         if filename.endswith(".msg"):
 257             return FileKind.MSG
 258
 259         error(filename, None, "unknown file kind")
 260
 261
 262 def check_style(enable_fixup):
 263     # We deal with two kinds of name.
 264     # - A "filename" is a full path to a file from the repository root.
 265     # - An "inclname" is how a file is referred to in a #include statement.
 266     #
 267     # Examples (filename -> inclname)
 268     # - "mfbt/Attributes.h"         -> "mozilla/Attributes.h"
 269     # - "mozglue/misc/TimeStamp.h   -> "mozilla/TimeStamp.h"
 270     # - "memory/mozalloc/mozalloc.h -> "mozilla/mozalloc.h"
 271     # - "js/public/Vector.h"        -> "js/Vector.h"
 272     # - "js/src/vm/String.h"        -> "vm/String.h"
 273
 274     non_js_dirnames = (
 275         "mfbt/",
 276         "memory/mozalloc/",
 277         "mozglue/",
 278         "intl/components/",
 279     )  # type: tuple(str)
 280     non_js_inclnames = set()  # type: set(inclname)
 281     js_names = dict()  # type: dict(filename, inclname)
 282
 283     # Process files in js/src.
 284     js_src_root = os.path.join("js", "src")
 285     for dirpath, dirnames, filenames in os.walk(js_src_root):
 286         if dirpath == js_src_root:
 287             # Skip any subdirectories that contain a config.status file
 288             # (likely objdirs).
 289             builddirs = []
 290             for dirname in dirnames:
 291                 path = os.path.join(dirpath, dirname, "config.status")
 292                 if os.path.isfile(path):
 293                     builddirs.append(dirname)
 294             for dirname in builddirs:
 295                 dirnames.remove(dirname)
 296         for filename in filenames:
 297             filepath = os.path.join(dirpath, filename).replace("\\", "/")
 298             if not filepath.startswith(
 299                 tuple(ignored_js_src_dirs)
 300             ) and filepath.endswith((".c", ".cpp", ".h", ".tbl", ".msg")):
 301                 inclname = filepath[len("js/src/") :]
 302                 js_names[filepath] = inclname
 303
 304     # Look for header files in directories in non_js_dirnames.
 305     for non_js_dir in non_js_dirnames:
 306         for dirpath, dirnames, filenames in os.walk(non_js_dir):
 307             for filename in filenames:
 308                 if filename.endswith(".h"):
 309                     inclname = "mozilla/" + filename
 310                     if non_js_dir == "intl/components/":
 311                         inclname = "mozilla/intl/" + filename
 312                     non_js_inclnames.add(inclname)
 313
 314     # Look for header files in js/public.
 315     js_public_root = os.path.join("js", "public")
 316     for dirpath, dirnames, filenames in os.walk(js_public_root):
 317         for filename in filenames:
 318             if filename.endswith((".h", ".msg")):
 319                 filepath = os.path.join(dirpath, filename).replace("\\", "/")
 320                 inclname = "js/" + filepath[len("js/public/") :]
 321                 js_names[filepath] = inclname
 322
 323     all_inclnames = non_js_inclnames | set(js_names.values())
 324
 325     edges = dict()  # type: dict(inclname, set(inclname))
 326
 327     # We don't care what's inside the MFBT and MOZALLOC files, but because they
 328     # are #included from JS files we have to add them to the inclusion graph.
 329     for inclname in non_js_inclnames:
 330         edges[inclname] = set()
 331
 332     # Process all the JS files.
 333     for filename in sorted(js_names.keys()):
 334         inclname = js_names[filename]
 335         file_kind = FileKind.get(filename)
 336         if (
 337             file_kind == FileKind.C
 338             or file_kind == FileKind.CPP
 339             or file_kind == FileKind.H
 340             or file_kind == FileKind.INL_H
 341         ):
 342             included_h_inclnames = set()  # type: set(inclname)
 343
 344             with open(filename, encoding="utf-8") as f:
 345                 code = read_file(f)
 346
 347             if enable_fixup:
 348                 code = code.sorted(inclname)
 349                 with open(filename, "w") as f:
 350                     f.write(code.to_source())
 351
 352             check_file(
 353                 filename, inclname, file_kind, code, all_inclnames, included_h_inclnames
 354             )
 355
 356         edges[inclname] = included_h_inclnames
 357
 358     find_cycles(all_inclnames, edges)
 359
 360     # Compare expected and actual output.
 361     difflines = difflib.unified_diff(
 362         expected_output,
 363         actual_output,
 364         fromfile="check_spidermonkey_style.py expected output",
 365         tofile="check_spidermonkey_style.py actual output",
 366     )
 367     ok = True
 368     for diffline in difflines:
 369         ok = False
 370         print(diffline, end="")
 371
 372     return ok
 373
 374
 375 def module_name(name):
 376     """Strip the trailing .cpp, .h, inlines.h or -inl.h from a filename."""
 377
 378     return (
 379         name.replace("inlines.h", "")
 380         .replace("-inl.h", "")
 381         .replace(".h", "")
 382         .replace(".cpp", "")
 383     )  # NOQA: E501
 384
 385
 386 def is_module_header(enclosing_inclname, header_inclname):
 387     """Determine if an included name is the "module header", i.e. should be
 388     first in the file."""
 389
 390     module = module_name(enclosing_inclname)
 391
 392     # Normal case, for example:
 393     #   module == "vm/Runtime", header_inclname == "vm/Runtime.h".
 394     if module == module_name(header_inclname):
 395         return True
 396
 397     # A public header, for example:
 398     #
 399     #   module == "vm/CharacterEncoding",
 400     #   header_inclname == "js/CharacterEncoding.h"
 401     #
 402     # or (for implementation files for js/public/*/*.h headers)
 403     #
 404     #   module == "vm/SourceHook",
 405     #   header_inclname == "js/experimental/SourceHook.h"
 406     m = re.match(r"js\/.*?([^\/]+)\.h", header_inclname)
 407     if m is not None and module.endswith("/" + m.group(1)):
 408         return True
 409
 410     return False
 411
 412
 413 class Include(object):
 414     """Important information for a single #include statement."""
 415
 416     def __init__(self, include_prefix, inclname, line_suffix, linenum, is_system):
 417         self.include_prefix = include_prefix
 418         self.line_suffix = line_suffix
 419         self.inclname = inclname
 420         self.linenum = linenum
 421         self.is_system = is_system
 422
 423     def is_style_relevant(self):
 424         # Includes are style-relevant; that is, they're checked by the pairwise
 425         # style-checking algorithm in check_file.
 426         return True
 427
 428     def section(self, enclosing_inclname):
 429         """Identify which section inclname belongs to.
 430
 431         The section numbers are as follows.
 432           0. Module header (e.g. jsfoo.h or jsfooinlines.h within jsfoo.cpp)
 433           1. mozilla/Foo.h
 434           2. <foo.h> or <foo>
 435           3. jsfoo.h, prmjtime.h, etc
 436           4. foo/Bar.h
 437           5. jsfooinlines.h
 438           6. foo/Bar-inl.h
 439           7. non-.h, e.g. *.tbl, *.msg (these can be scattered throughout files)
 440         """
 441
 442         if self.is_system:
 443             return 2
 444
 445         if not self.inclname.endswith(".h"):
 446             return 7
 447
 448         # A couple of modules have the .h file in js/ and the .cpp file elsewhere and so need
 449         # special handling.
 450         if is_module_header(enclosing_inclname, self.inclname):
 451             return 0
 452
 453         if "/" in self.inclname:
 454             if self.inclname.startswith("mozilla/"):
 455                 return 1
 456
 457             if self.inclname.endswith("-inl.h"):
 458                 return 6
 459
 460             return 4
 461
 462         if self.inclname.endswith("inlines.h"):
 463             return 5
 464
 465         return 3
 466
 467     def quote(self):
 468         if self.is_system:
 469             return "<" + self.inclname + ">"
 470         else:
 471             return '"' + self.inclname + '"'
 472
 473     def sort_key(self, enclosing_inclname):
 474         return (self.section(enclosing_inclname), self.inclname.lower())
 475
 476     def to_source(self):
 477         return self.include_prefix + self.quote() + self.line_suffix + "\n"
 478
 479
 480 class CppBlock(object):
 481     """C preprocessor block: a whole file or a single #if/#elif/#else block.
 482
 483     A #if/#endif block is the contents of a #if/#endif (or similar) section.
 484     The top-level block, which is not within a #if/#endif pair, is also
 485     considered a block.
 486
 487     Each kid is either an Include (representing a #include), OrdinaryCode, or
 488     a nested CppBlock."""
 489
 490     def __init__(self, start_line=""):
 491         self.start = start_line
 492         self.end = ""
 493         self.kids = []
 494
 495     def is_style_relevant(self):
 496         return True
 497
 498     def append_ordinary_line(self, line):
 499         if len(self.kids) == 0 or not isinstance(self.kids[-1], OrdinaryCode):
 500             self.kids.append(OrdinaryCode())
 501         self.kids[-1].lines.append(line)
 502
 503     def style_relevant_kids(self):
 504         """Return a list of kids in this block that are style-relevant."""
 505         return [kid for kid in self.kids if kid.is_style_relevant()]
 506
 507     def sorted(self, enclosing_inclname):
 508         """Return a hopefully-sorted copy of this block. Implements --fixup.
 509
 510         When in doubt, this leaves the code unchanged.
 511         """
 512
 513         def pretty_sorted_includes(includes):
 514             """Return a new list containing the given includes, in order,
 515             with blank lines separating sections."""
 516             keys = [inc.sort_key(enclosing_inclname) for inc in includes]
 517             if sorted(keys) == keys:
 518                 return includes  # if nothing is out of order, don't touch anything
 519
 520             output = []
 521             current_section = None
 522             for (section, _), inc in sorted(zip(keys, includes)):
 523                 if current_section is not None and section != current_section:
 524                     output.append(OrdinaryCode(["\n"]))  # blank line
 525                 output.append(inc)
 526                 current_section = section
 527             return output
 528
 529         def should_try_to_sort(includes):
 530             if "tests/style/BadIncludes" in enclosing_inclname:
 531                 return False  # don't straighten the counterexample
 532             if any(inc.inclname in oddly_ordered_inclnames for inc in includes):
 533                 return False  # don't sort batches containing odd includes
 534             if includes == sorted(
 535                 includes, key=lambda inc: inc.sort_key(enclosing_inclname)
 536             ):
 537                 return False  # it's already sorted, avoid whitespace-only fixups
 538             return True
 539
 540         # The content of the eventual output of this method.
 541         output = []
 542
 543         # The current batch of includes to sort. This list only ever contains Include objects
 544         # and whitespace OrdinaryCode objects.
 545         batch = []
 546
 547         def flush_batch():
 548             """Sort the contents of `batch` and move it to `output`."""
 549
 550             assert all(
 551                 isinstance(item, Include)
 552                 or (isinstance(item, OrdinaryCode) and "".join(item.lines).isspace())
 553                 for item in batch
 554             )
 555
 556             # Here we throw away the blank lines.
 557             # `pretty_sorted_includes` puts them back.
 558             includes = []
 559             last_include_index = -1
 560             for i, item in enumerate(batch):
 561                 if isinstance(item, Include):
 562                     includes.append(item)
 563                     last_include_index = i
 564             cutoff = last_include_index + 1
 565
 566             if should_try_to_sort(includes):
 567                 output.extend(pretty_sorted_includes(includes) + batch[cutoff:])
 568             else:
 569                 output.extend(batch)
 570             del batch[:]
 571
 572         for kid in self.kids:
 573             if isinstance(kid, CppBlock):
 574                 flush_batch()
 575                 output.append(kid.sorted(enclosing_inclname))
 576             elif isinstance(kid, Include):
 577                 batch.append(kid)
 578             else:
 579                 assert isinstance(kid, OrdinaryCode)
 580                 if kid.to_source().isspace():
 581                     batch.append(kid)
 582                 else:
 583                     flush_batch()
 584                     output.append(kid)
 585         flush_batch()
 586
 587         result = CppBlock()
 588         result.start = self.start
 589         result.end = self.end
 590         result.kids = output
 591         return result
 592
 593     def to_source(self):
 594         return self.start + "".join(kid.to_source() for kid in self.kids) + self.end
 595
 596
 597 class OrdinaryCode(object):
 598     """A list of lines of code that aren't #include/#if/#else/#endif lines."""
 599
 600     def __init__(self, lines=None):
 601         self.lines = lines if lines is not None else []
 602
 603     def is_style_relevant(self):
 604         return False
 605
 606     def to_source(self):
 607         return "".join(self.lines)
 608
 609
 610 # A "snippet" is one of:
 611 #
 612 # *   Include - representing an #include line
 613 # *   CppBlock - a whole file or #if/#elif/#else block; contains a list of snippets
 614 # *   OrdinaryCode - representing lines of non-#include-relevant code
 615
 616
 617 def read_file(f):
 618     block_stack = [CppBlock()]
 619
 620     # Extract the #include statements as a tree of snippets.
 621     for linenum, line in enumerate(f, start=1):
 622         if line.lstrip().startswith("#"):
 623             # Look for a |#include "..."| line.
 624             m = re.match(r'(\s*#\s*include\s+)"([^"]*)"(.*)', line)
 625             if m is not None:
 626                 prefix, inclname, suffix = m.groups()
 627                 block_stack[-1].kids.append(
 628                     Include(prefix, inclname, suffix, linenum, is_system=False)
 629                 )
 630                 continue
 631
 632             # Look for a |#include <...>| line.
 633             m = re.match(r"(\s*#\s*include\s+)<([^>]*)>(.*)", line)
 634             if m is not None:
 635                 prefix, inclname, suffix = m.groups()
 636                 block_stack[-1].kids.append(
 637                     Include(prefix, inclname, suffix, linenum, is_system=True)
 638                 )
 639                 continue
 640
 641             # Look for a |#{if,ifdef,ifndef}| line.
 642             m = re.match(r"\s*#\s*(if|ifdef|ifndef)\b", line)
 643             if m is not None:
 644                 # Open a new block.
 645                 new_block = CppBlock(line)
 646                 block_stack[-1].kids.append(new_block)
 647                 block_stack.append(new_block)
 648                 continue
 649
 650             # Look for a |#{elif,else}| line.
 651             m = re.match(r"\s*#\s*(elif|else)\b", line)
 652             if m is not None:
 653                 # Close the current block, and open an adjacent one.
 654                 block_stack.pop()
 655                 new_block = CppBlock(line)
 656                 block_stack[-1].kids.append(new_block)
 657                 block_stack.append(new_block)
 658                 continue
 659
 660             # Look for a |#endif| line.
 661             m = re.match(r"\s*#\s*endif\b", line)
 662             if m is not None:
 663                 # Close the current block.
 664                 block_stack.pop().end = line
 665                 if len(block_stack) == 0:
 666                     raise ValueError("#endif without #if at line " + str(linenum))
 667                 continue
 668
 669         # Otherwise, we have an ordinary line.
 670         block_stack[-1].append_ordinary_line(line)
 671
 672     if len(block_stack) > 1:
 673         raise ValueError("unmatched #if")
 674     return block_stack[-1]
 675
 676
 677 def check_file(
 678     filename, inclname, file_kind, code, all_inclnames, included_h_inclnames
 679 ):
 680     def check_include_statement(include):
 681         """Check the style of a single #include statement."""
 682
 683         if include.is_system:
 684             # Check it is not a known local file (in which case it's probably a system header).
 685             if (
 686                 include.inclname in included_inclnames_to_ignore
 687                 or include.inclname in all_inclnames
 688             ):
 689                 error(
 690                     filename,
 691                     include.linenum,
 692                     include.quote() + " should be included using",
 693                     'the #include "..." form',
 694                 )
 695
 696         else:
 697             msg = deprecated_inclnames.get(include.inclname)
 698             if msg:
 699                 error(
 700                     filename,
 701                     include.linenum,
 702                     include.quote() + " is deprecated: " + msg,
 703                 )
 704
 705             if file_kind == FileKind.H or file_kind == FileKind.INL_H:
 706                 msg = deprecated_inclnames_in_header.get(include.inclname)
 707                 if msg and filename not in deprecated_inclnames_in_header_excludes:
 708                     error(
 709                         filename,
 710                         include.linenum,
 711                         include.quote() + " is deprecated: " + msg,
 712                     )
 713
 714             if include.inclname not in included_inclnames_to_ignore:
 715                 included_kind = FileKind.get(include.inclname)
 716
 717                 # Check the #include path has the correct form.
 718                 if include.inclname not in all_inclnames:
 719                     error(
 720                         filename,
 721                         include.linenum,
 722                         include.quote() + " is included using the wrong path;",
 723                         "did you forget a prefix, or is the file not yet committed?",
 724                     )
 725
 726                 # Record inclusions of .h files for cycle detection later.
 727                 # (Exclude .tbl and .msg files.)
 728                 elif included_kind == FileKind.H or included_kind == FileKind.INL_H:
 729                     included_h_inclnames.add(include.inclname)
 730
 731                 # Check a H file doesn't #include an INL_H file.
 732                 if file_kind == FileKind.H and included_kind == FileKind.INL_H:
 733                     error(
 734                         filename,
 735                         include.linenum,
 736                         "vanilla header includes an inline-header file "
 737                         + include.quote(),
 738                     )
 739
 740                 # Check a file doesn't #include itself.  (We do this here because the cycle
 741                 # detection below doesn't detect this case.)
 742                 if inclname == include.inclname:
 743                     error(filename, include.linenum, "the file includes itself")
 744
 745     def check_includes_order(include1, include2):
 746         """Check the ordering of two #include statements."""
 747
 748         if (
 749             include1.inclname in oddly_ordered_inclnames
 750             or include2.inclname in oddly_ordered_inclnames
 751         ):
 752             return
 753
 754         section1 = include1.section(inclname)
 755         section2 = include2.section(inclname)
 756         if (section1 > section2) or (
 757             (section1 == section2)
 758             and (include1.inclname.lower() > include2.inclname.lower())
 759         ):
 760             error(
 761                 filename,
 762                 str(include1.linenum) + ":" + str(include2.linenum),
 763                 include1.quote() + " should be included after " + include2.quote(),
 764             )
 765
 766     # Check the extracted #include statements, both individually, and the ordering of
 767     # adjacent pairs that live in the same block.
 768     def pair_traverse(prev, this):
 769         if isinstance(this, Include):
 770             check_include_statement(this)
 771             if isinstance(prev, Include):
 772                 check_includes_order(prev, this)
 773         else:
 774             kids = this.style_relevant_kids()
 775             for prev2, this2 in zip([None] + kids[0:-1], kids):
 776                 pair_traverse(prev2, this2)
 777
 778     pair_traverse(None, code)
 779
 780
 781 def find_cycles(all_inclnames, edges):
 782     """Find and draw any cycles."""
 783
 784     SCCs = tarjan(all_inclnames, edges)
 785
 786     # The various sorted() calls below ensure the output is deterministic.
 787
 788     def draw_SCC(c):
 789         cset = set(c)
 790         drawn = set()
 791
 792         def draw(v, indent):
 793             out("   " * indent + ("-> " if indent else "   ") + v)
 794             if v in drawn:
 795                 return
 796             drawn.add(v)
 797             for succ in sorted(edges[v]):
 798                 if succ in cset:
 799                     draw(succ, indent + 1)
 800
 801         draw(sorted(c)[0], 0)
 802         out("")
 803
 804     have_drawn_an_SCC = False
 805     for scc in sorted(SCCs):
 806         if len(scc) != 1:
 807             if not have_drawn_an_SCC:
 808                 error("(multiple files)", None, "header files form one or more cycles")
 809                 have_drawn_an_SCC = True
 810
 811             draw_SCC(scc)
 812
 813
 814 # Tarjan's algorithm for finding the strongly connected components (SCCs) of a graph.
 815 # https://en.wikipedia.org/wiki/Tarjan%27s_strongly_connected_components_algorithm
 816 def tarjan(V, E):
 817     vertex_index = {}
 818     vertex_lowlink = {}
 819     index = 0
 820     S = []
 821     all_SCCs = []
 822
 823     def strongconnect(v, index):
 824         # Set the depth index for v to the smallest unused index
 825         vertex_index[v] = index
 826         vertex_lowlink[v] = index
 827         index += 1
 828         S.append(v)
 829
 830         # Consider successors of v
 831         for w in E[v]:
 832             if w not in vertex_index:
 833                 # Successor w has not yet been visited; recurse on it
 834                 index = strongconnect(w, index)
 835                 vertex_lowlink[v] = min(vertex_lowlink[v], vertex_lowlink[w])
 836             elif w in S:
 837                 # Successor w is in stack S and hence in the current SCC
 838                 vertex_lowlink[v] = min(vertex_lowlink[v], vertex_index[w])
 839
 840         # If v is a root node, pop the stack and generate an SCC
 841         if vertex_lowlink[v] == vertex_index[v]:
 842             i = S.index(v)
 843             scc = S[i:]
 844             del S[i:]
 845             all_SCCs.append(scc)
 846
 847         return index
 848
 849     for v in V:
 850         if v not in vertex_index:
 851             index = strongconnect(v, index)
 852
 853     return all_SCCs
 854
 855
 856 def main():
 857     if sys.argv[1:] == ["--fixup"]:
 858         # Sort #include directives in-place.  Fixup mode doesn't solve
 859         # all possible silliness that the script checks for; it's just a
 860         # hack for the common case where renaming a header causes style
 861         # errors.
 862         fixup = True
 863     elif sys.argv[1:] == []:
 864         fixup = False
 865     else:
 866         print(
 867             "TEST-UNEXPECTED-FAIL | check_spidermonkey_style.py | unexpected command "
 868             "line options: " + repr(sys.argv[1:])
 869         )
 870         sys.exit(1)
 871
 872     ok = check_style(fixup)
 873
 874     if ok:
 875         print("TEST-PASS | check_spidermonkey_style.py | ok")
 876     else:
 877         print(
 878             "TEST-UNEXPECTED-FAIL | check_spidermonkey_style.py | "
 879             + "actual output does not match expected output;  diff is above."
 880         )
 881         print(
 882             "TEST-UNEXPECTED-FAIL | check_spidermonkey_style.py | "
 883             + "Hint: If the problem is that you renamed a header, and many #includes "
 884             + "are no longer in alphabetical order, commit your work and then try "
 885             + "`check_spidermonkey_style.py --fixup`. "
 886             + "You need to commit first because --fixup modifies your files in place."
 887         )
 888
 889     sys.exit(0 if ok else 1)
 890
 891
 892 if __name__ == "__main__":
 893     main()