Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 899 insertions, 0 deletions

diff --git a/config/check_spidermonkey_style.py b/config/check_spidermonkey_style.py
new file mode 100644
index 0000000000..1bb02888d6
--- /dev/null
+++ b/config/check_spidermonkey_style.py
@@ -0,0 +1,899 @@
+# vim: set ts=8 sts=4 et sw=4 tw=99:
+# 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/.
+
+# ----------------------------------------------------------------------------
+# This script checks various aspects of SpiderMonkey code style.  The current checks are as
+# follows.
+#
+# We check the following things in headers.
+#
+# - No cyclic dependencies.
+#
+# - No normal header should #include a inlines.h/-inl.h file.
+#
+# - #ifndef wrappers should have the right form. (XXX: not yet implemented)
+#   - Every header file should have one.
+#   - The guard name used should be appropriate for the filename.
+#
+# We check the following things in all files.
+#
+# - #includes should have full paths, e.g. "jit/Ion.h", not "Ion.h".
+#
+# - #includes should use the appropriate form for system headers (<...>) and
+#   local headers ("...").
+#
+# - #includes should be ordered correctly.
+#   - Each one should be in the correct section.
+#   - Alphabetical order should be used within sections.
+#   - Sections should be in the right order.
+#   Note that the presence of #if/#endif blocks complicates things, to the
+#   point that it's not always clear where a conditionally-compiled #include
+#   statement should go, even to a human.  Therefore, we check the #include
+#   statements within each #if/#endif block (including nested ones) in
+#   isolation, but don't try to do any order checking between such blocks.
+# ----------------------------------------------------------------------------
+
+import difflib
+import os
+import re
+import sys
+
+# We don't bother checking files in these directories, because they're (a) auxiliary or (b)
+# imported code that doesn't follow our coding style.
+ignored_js_src_dirs = [
+    "js/src/config/",  # auxiliary stuff
+    "js/src/ctypes/libffi/",  # imported code
+    "js/src/devtools/",  # auxiliary stuff
+    "js/src/editline/",  # imported code
+    "js/src/gdb/",  # auxiliary stuff
+    "js/src/vtune/",  # imported code
+    "js/src/zydis/",  # imported code
+]
+
+# We ignore #includes of these files, because they don't follow the usual rules.
+included_inclnames_to_ignore = set(
+    [
+        "ffi.h",  # generated in ctypes/libffi/
+        "devtools/Instruments.h",  # we ignore devtools/ in general
+        "double-conversion/double-conversion.h",  # strange MFBT case
+        "javascript-trace.h",  # generated in $OBJDIR if HAVE_DTRACE is defined
+        "frontend/ReservedWordsGenerated.h",  # generated in $OBJDIR
+        "frontend/smoosh_generated.h",  # generated in $OBJDIR
+        "gc/StatsPhasesGenerated.h",  # generated in $OBJDIR
+        "gc/StatsPhasesGenerated.inc",  # generated in $OBJDIR
+        "jit/ABIFunctionTypeGenerated.h",  # generated in $OBJDIR"
+        "jit/AtomicOperationsGenerated.h",  # generated in $OBJDIR
+        "jit/CacheIROpsGenerated.h",  # generated in $OBJDIR
+        "jit/LIROpsGenerated.h",  # generated in $OBJDIR
+        "jit/MIROpsGenerated.h",  # generated in $OBJDIR
+        "js/PrefsGenerated.h",  # generated in $OBJDIR
+        "js/ProfilingCategoryList.h",  # comes from mozglue/baseprofiler
+        "mozilla/glue/Debug.h",  # comes from mozglue/misc, shadowed by <mozilla/Debug.h>
+        "jscustomallocator.h",  # provided by embedders;  allowed to be missing
+        "js-config.h",  # generated in $OBJDIR
+        "fdlibm.h",  # fdlibm
+        "FuzzerDefs.h",  # included without a path
+        "FuzzingInterface.h",  # included without a path
+        "ICU4XGraphemeClusterSegmenter.h",  # ICU4X
+        "ICU4XSentenceSegmenter.h",  # ICU4X
+        "ICU4XWordSegmenter.h",  # ICU4X
+        "mozmemory.h",  # included without a path
+        "pratom.h",  # NSPR
+        "prcvar.h",  # NSPR
+        "prerror.h",  # NSPR
+        "prinit.h",  # NSPR
+        "prio.h",  # NSPR
+        "private/pprio.h",  # NSPR
+        "prlink.h",  # NSPR
+        "prlock.h",  # NSPR
+        "prprf.h",  # NSPR
+        "prthread.h",  # NSPR
+        "prtypes.h",  # NSPR
+        "selfhosted.out.h",  # generated in $OBJDIR
+        "shellmoduleloader.out.h",  # generated in $OBJDIR
+        "unicode/locid.h",  # ICU
+        "unicode/uchar.h",  # ICU
+        "unicode/uniset.h",  # ICU
+        "unicode/unistr.h",  # ICU
+        "unicode/utypes.h",  # ICU
+        "vtune/VTuneWrapper.h",  # VTune
+        "wasm/WasmBuiltinModuleGenerated.h",  # generated in $OBJDIR"
+        "zydis/ZydisAPI.h",  # Zydis
+    ]
+)
+
+deprecated_inclnames = {
+    "mozilla/Unused.h": "Use [[nodiscard]] and (void)expr casts instead.",
+}
+
+# JSAPI functions should be included through headers from js/public instead of
+# using the old, catch-all jsapi.h file.
+deprecated_inclnames_in_header = {
+    "jsapi.h": "Prefer including headers from js/public.",
+}
+
+# Temporary exclusions for files which still need to include jsapi.h.
+deprecated_inclnames_in_header_excludes = {
+    "js/src/vm/Compartment-inl.h",  # for JS::InformalValueTypeName
+    "js/src/jsapi-tests/tests.h",  # for JS_ValueToSource
+}
+
+# These files have additional constraints on where they are #included, so we
+# ignore #includes of them when checking #include ordering.
+oddly_ordered_inclnames = set(
+    [
+        "ctypes/typedefs.h",  # Included multiple times in the body of ctypes/CTypes.h
+        # Included in the body of frontend/TokenStream.h
+        "frontend/ReservedWordsGenerated.h",
+        "gc/StatsPhasesGenerated.h",  # Included in the body of gc/Statistics.h
+        "gc/StatsPhasesGenerated.inc",  # Included in the body of gc/Statistics.cpp
+        "psapi.h",  # Must be included after "util/WindowsWrapper.h" on Windows
+        "machine/endian.h",  # Must be included after <sys/types.h> on BSD
+        "process.h",  # Windows-specific
+        "winbase.h",  # Must precede other system headers(?)
+        "windef.h",  # Must precede other system headers(?)
+        "windows.h",  # Must precede other system headers(?)
+    ]
+)
+
+# The files in tests/style/ contain code that fails this checking in various
+# ways.  Here is the output we expect.  If the actual output differs from
+# this, one of the following must have happened.
+# - New SpiderMonkey code violates one of the checked rules.
+# - The tests/style/ files have changed without expected_output being changed
+#   accordingly.
+# - This script has been broken somehow.
+#
+expected_output = """\
+js/src/tests/style/BadIncludes.h:3: error:
+    the file includes itself
+
+js/src/tests/style/BadIncludes.h:6: error:
+    "BadIncludes2.h" is included using the wrong path;
+    did you forget a prefix, or is the file not yet committed?
+
+js/src/tests/style/BadIncludes.h:8: error:
+    <tests/style/BadIncludes2.h> should be included using
+    the #include "..." form
+
+js/src/tests/style/BadIncludes.h:10: error:
+    "stdio.h" is included using the wrong path;
+    did you forget a prefix, or is the file not yet committed?
+
+js/src/tests/style/BadIncludes.h:12: error:
+    "mozilla/Unused.h" is deprecated: Use [[nodiscard]] and (void)expr casts instead.
+
+js/src/tests/style/BadIncludes2.h:1: error:
+    vanilla header includes an inline-header file "tests/style/BadIncludes2-inl.h"
+
+js/src/tests/style/BadIncludesOrder-inl.h:5:6: error:
+    "vm/JSScript-inl.h" should be included after "vm/Interpreter-inl.h"
+
+js/src/tests/style/BadIncludesOrder-inl.h:6:7: error:
+    "vm/Interpreter-inl.h" should be included after "js/Value.h"
+
+js/src/tests/style/BadIncludesOrder-inl.h:7:8: error:
+    "js/Value.h" should be included after "ds/LifoAlloc.h"
+
+js/src/tests/style/BadIncludesOrder-inl.h:9: error:
+    "jsapi.h" is deprecated: Prefer including headers from js/public.
+
+js/src/tests/style/BadIncludesOrder-inl.h:8:9: error:
+    "ds/LifoAlloc.h" should be included after "jsapi.h"
+
+js/src/tests/style/BadIncludesOrder-inl.h:9:10: error:
+    "jsapi.h" should be included after <stdio.h>
+
+js/src/tests/style/BadIncludesOrder-inl.h:10:11: error:
+    <stdio.h> should be included after "mozilla/HashFunctions.h"
+
+js/src/tests/style/BadIncludesOrder-inl.h:20: error:
+    "jsapi.h" is deprecated: Prefer including headers from js/public.
+
+js/src/tests/style/BadIncludesOrder-inl.h:28:29: error:
+    "vm/JSScript.h" should be included after "vm/JSFunction.h"
+
+(multiple files): error:
+    header files form one or more cycles
+
+   tests/style/HeaderCycleA1.h
+   -> tests/style/HeaderCycleA2.h
+      -> tests/style/HeaderCycleA3.h
+         -> tests/style/HeaderCycleA1.h
+
+   tests/style/HeaderCycleB1-inl.h
+   -> tests/style/HeaderCycleB2-inl.h
+      -> tests/style/HeaderCycleB3-inl.h
+         -> tests/style/HeaderCycleB4-inl.h
+            -> tests/style/HeaderCycleB1-inl.h
+            -> tests/style/jsheadercycleB5inlines.h
+               -> tests/style/HeaderCycleB1-inl.h
+      -> tests/style/HeaderCycleB4-inl.h
+
+""".splitlines(
+    True
+)
+
+actual_output = []
+
+
+def out(*lines):
+    for line in lines:
+        actual_output.append(line + "\n")
+
+
+def error(filename, linenum, *lines):
+    location = filename
+    if linenum is not None:
+        location += ":" + str(linenum)
+    out(location + ": error:")
+    for line in lines:
+        out("    " + line)
+    out("")
+
+
+class FileKind(object):
+    C = 1
+    CPP = 2
+    INL_H = 3
+    H = 4
+    TBL = 5
+    MSG = 6
+
+    @staticmethod
+    def get(filename):
+        if filename.endswith(".c"):
+            return FileKind.C
+
+        if filename.endswith(".cpp"):
+            return FileKind.CPP
+
+        if filename.endswith(("inlines.h", "-inl.h")):
+            return FileKind.INL_H
+
+        if filename.endswith(".h"):
+            return FileKind.H
+
+        if filename.endswith(".tbl"):
+            return FileKind.TBL
+
+        if filename.endswith(".msg"):
+            return FileKind.MSG
+
+        error(filename, None, "unknown file kind")
+
+
+def check_style(enable_fixup):
+    # We deal with two kinds of name.
+    # - A "filename" is a full path to a file from the repository root.
+    # - An "inclname" is how a file is referred to in a #include statement.
+    #
+    # Examples (filename -> inclname)
+    # - "mfbt/Attributes.h"         -> "mozilla/Attributes.h"
+    # - "mozglue/misc/TimeStamp.h   -> "mozilla/TimeStamp.h"
+    # - "memory/mozalloc/mozalloc.h -> "mozilla/mozalloc.h"
+    # - "js/public/Vector.h"        -> "js/Vector.h"
+    # - "js/src/vm/String.h"        -> "vm/String.h"
+
+    non_js_dirnames = (
+        "mfbt/",
+        "memory/mozalloc/",
+        "mozglue/",
+        "intl/components/",
+    )  # type: tuple(str)
+    non_js_inclnames = set()  # type: set(inclname)
+    js_names = dict()  # type: dict(filename, inclname)
+
+    # Process files in js/src.
+    js_src_root = os.path.join("js", "src")
+    for dirpath, dirnames, filenames in os.walk(js_src_root):
+        if dirpath == js_src_root:
+            # Skip any subdirectories that contain a config.status file
+            # (likely objdirs).
+            builddirs = []
+            for dirname in dirnames:
+                path = os.path.join(dirpath, dirname, "config.status")
+                if os.path.isfile(path):
+                    builddirs.append(dirname)
+            for dirname in builddirs:
+                dirnames.remove(dirname)
+        for filename in filenames:
+            filepath = os.path.join(dirpath, filename).replace("\\", "/")
+            if not filepath.startswith(
+                tuple(ignored_js_src_dirs)
+            ) and filepath.endswith((".c", ".cpp", ".h", ".tbl", ".msg")):
+                inclname = filepath[len("js/src/") :]
+                js_names[filepath] = inclname
+
+    # Look for header files in directories in non_js_dirnames.
+    for non_js_dir in non_js_dirnames:
+        for dirpath, dirnames, filenames in os.walk(non_js_dir):
+            for filename in filenames:
+                if filename.endswith(".h"):
+                    inclname = "mozilla/" + filename
+                    if non_js_dir == "intl/components/":
+                        inclname = "mozilla/intl/" + filename
+                    non_js_inclnames.add(inclname)
+
+    # Look for header files in js/public.
+    js_public_root = os.path.join("js", "public")
+    for dirpath, dirnames, filenames in os.walk(js_public_root):
+        for filename in filenames:
+            if filename.endswith((".h", ".msg")):
+                filepath = os.path.join(dirpath, filename).replace("\\", "/")
+                inclname = "js/" + filepath[len("js/public/") :]
+                js_names[filepath] = inclname
+
+    all_inclnames = non_js_inclnames | set(js_names.values())
+
+    edges = dict()  # type: dict(inclname, set(inclname))
+
+    # We don't care what's inside the MFBT and MOZALLOC files, but because they
+    # are #included from JS files we have to add them to the inclusion graph.
+    for inclname in non_js_inclnames:
+        edges[inclname] = set()
+
+    # Process all the JS files.
+    for filename in sorted(js_names.keys()):
+        inclname = js_names[filename]
+        file_kind = FileKind.get(filename)
+        if (
+            file_kind == FileKind.C
+            or file_kind == FileKind.CPP
+            or file_kind == FileKind.H
+            or file_kind == FileKind.INL_H
+        ):
+            included_h_inclnames = set()  # type: set(inclname)
+
+            with open(filename, encoding="utf-8") as f:
+                code = read_file(f)
+
+            if enable_fixup:
+                code = code.sorted(inclname)
+                with open(filename, "w") as f:
+                    f.write(code.to_source())
+
+            check_file(
+                filename, inclname, file_kind, code, all_inclnames, included_h_inclnames
+            )
+
+        edges[inclname] = included_h_inclnames
+
+    find_cycles(all_inclnames, edges)
+
+    # Compare expected and actual output.
+    difflines = difflib.unified_diff(
+        expected_output,
+        actual_output,
+        fromfile="check_spidermonkey_style.py expected output",
+        tofile="check_spidermonkey_style.py actual output",
+    )
+    ok = True
+    for diffline in difflines:
+        ok = False
+        print(diffline, end="")
+
+    return ok
+
+
+def module_name(name):
+    """Strip the trailing .cpp, .h, inlines.h or -inl.h from a filename."""
+
+    return (
+        name.replace("inlines.h", "")
+        .replace("-inl.h", "")
+        .replace(".h", "")
+        .replace(".cpp", "")
+    )  # NOQA: E501
+
+
+def is_module_header(enclosing_inclname, header_inclname):
+    """Determine if an included name is the "module header", i.e. should be
+    first in the file."""
+
+    module = module_name(enclosing_inclname)
+
+    # Normal case, for example:
+    #   module == "vm/Runtime", header_inclname == "vm/Runtime.h".
+    if module == module_name(header_inclname):
+        return True
+
+    # A public header, for example:
+    #
+    #   module == "vm/CharacterEncoding",
+    #   header_inclname == "js/CharacterEncoding.h"
+    #
+    # or (for implementation files for js/public/*/*.h headers)
+    #
+    #   module == "vm/SourceHook",
+    #   header_inclname == "js/experimental/SourceHook.h"
+    m = re.match(r"js\/.*?([^\/]+)\.h", header_inclname)
+    if m is not None and module.endswith("/" + m.group(1)):
+        return True
+
+    return False
+
+
+class Include(object):
+    """Important information for a single #include statement."""
+
+    def __init__(self, include_prefix, inclname, line_suffix, linenum, is_system):
+        self.include_prefix = include_prefix
+        self.line_suffix = line_suffix
+        self.inclname = inclname
+        self.linenum = linenum
+        self.is_system = is_system
+
+    def is_style_relevant(self):
+        # Includes are style-relevant; that is, they're checked by the pairwise
+        # style-checking algorithm in check_file.
+        return True
+
+    def section(self, enclosing_inclname):
+        """Identify which section inclname belongs to.
+
+        The section numbers are as follows.
+          0. Module header (e.g. jsfoo.h or jsfooinlines.h within jsfoo.cpp)
+          1. mozilla/Foo.h
+          2. <foo.h> or <foo>
+          3. jsfoo.h, prmjtime.h, etc
+          4. foo/Bar.h
+          5. jsfooinlines.h
+          6. foo/Bar-inl.h
+          7. non-.h, e.g. *.tbl, *.msg (these can be scattered throughout files)
+        """
+
+        if self.is_system:
+            return 2
+
+        if not self.inclname.endswith(".h"):
+            return 7
+
+        # A couple of modules have the .h file in js/ and the .cpp file elsewhere and so need
+        # special handling.
+        if is_module_header(enclosing_inclname, self.inclname):
+            return 0
+
+        if "/" in self.inclname:
+            if self.inclname.startswith("mozilla/"):
+                return 1
+
+            if self.inclname.endswith("-inl.h"):
+                return 6
+
+            return 4
+
+        if self.inclname.endswith("inlines.h"):
+            return 5
+
+        return 3
+
+    def quote(self):
+        if self.is_system:
+            return "<" + self.inclname + ">"
+        else:
+            return '"' + self.inclname + '"'
+
+    def sort_key(self, enclosing_inclname):
+        return (self.section(enclosing_inclname), self.inclname.lower())
+
+    def to_source(self):
+        return self.include_prefix + self.quote() + self.line_suffix + "\n"
+
+
+class CppBlock(object):
+    """C preprocessor block: a whole file or a single #if/#elif/#else block.
+
+    A #if/#endif block is the contents of a #if/#endif (or similar) section.
+    The top-level block, which is not within a #if/#endif pair, is also
+    considered a block.
+
+    Each kid is either an Include (representing a #include), OrdinaryCode, or
+    a nested CppBlock."""
+
+    def __init__(self, start_line=""):
+        self.start = start_line
+        self.end = ""
+        self.kids = []
+
+    def is_style_relevant(self):
+        return True
+
+    def append_ordinary_line(self, line):
+        if len(self.kids) == 0 or not isinstance(self.kids[-1], OrdinaryCode):
+            self.kids.append(OrdinaryCode())
+        self.kids[-1].lines.append(line)
+
+    def style_relevant_kids(self):
+        """Return a list of kids in this block that are style-relevant."""
+        return [kid for kid in self.kids if kid.is_style_relevant()]
+
+    def sorted(self, enclosing_inclname):
+        """Return a hopefully-sorted copy of this block. Implements --fixup.
+
+        When in doubt, this leaves the code unchanged.
+        """
+
+        def pretty_sorted_includes(includes):
+            """Return a new list containing the given includes, in order,
+            with blank lines separating sections."""
+            keys = [inc.sort_key(enclosing_inclname) for inc in includes]
+            if sorted(keys) == keys:
+                return includes  # if nothing is out of order, don't touch anything
+
+            output = []
+            current_section = None
+            for (section, _), inc in sorted(zip(keys, includes)):
+                if current_section is not None and section != current_section:
+                    output.append(OrdinaryCode(["\n"]))  # blank line
+                output.append(inc)
+                current_section = section
+            return output
+
+        def should_try_to_sort(includes):
+            if "tests/style/BadIncludes" in enclosing_inclname:
+                return False  # don't straighten the counterexample
+            if any(inc.inclname in oddly_ordered_inclnames for inc in includes):
+                return False  # don't sort batches containing odd includes
+            if includes == sorted(
+                includes, key=lambda inc: inc.sort_key(enclosing_inclname)
+            ):
+                return False  # it's already sorted, avoid whitespace-only fixups
+            return True
+
+        # The content of the eventual output of this method.
+        output = []
+
+        # The current batch of includes to sort. This list only ever contains Include objects
+        # and whitespace OrdinaryCode objects.
+        batch = []
+
+        def flush_batch():
+            """Sort the contents of `batch` and move it to `output`."""
+
+            assert all(
+                isinstance(item, Include)
+                or (isinstance(item, OrdinaryCode) and "".join(item.lines).isspace())
+                for item in batch
+            )
+
+            # Here we throw away the blank lines.
+            # `pretty_sorted_includes` puts them back.
+            includes = []
+            last_include_index = -1
+            for i, item in enumerate(batch):
+                if isinstance(item, Include):
+                    includes.append(item)
+                    last_include_index = i
+            cutoff = last_include_index + 1
+
+            if should_try_to_sort(includes):
+                output.extend(pretty_sorted_includes(includes) + batch[cutoff:])
+            else:
+                output.extend(batch)
+            del batch[:]
+
+        for kid in self.kids:
+            if isinstance(kid, CppBlock):
+                flush_batch()
+                output.append(kid.sorted(enclosing_inclname))
+            elif isinstance(kid, Include):
+                batch.append(kid)
+            else:
+                assert isinstance(kid, OrdinaryCode)
+                if kid.to_source().isspace():
+                    batch.append(kid)
+                else:
+                    flush_batch()
+                    output.append(kid)
+        flush_batch()
+
+        result = CppBlock()
+        result.start = self.start
+        result.end = self.end
+        result.kids = output
+        return result
+
+    def to_source(self):
+        return self.start + "".join(kid.to_source() for kid in self.kids) + self.end
+
+
+class OrdinaryCode(object):
+    """A list of lines of code that aren't #include/#if/#else/#endif lines."""
+
+    def __init__(self, lines=None):
+        self.lines = lines if lines is not None else []
+
+    def is_style_relevant(self):
+        return False
+
+    def to_source(self):
+        return "".join(self.lines)
+
+
+# A "snippet" is one of:
+#
+# *   Include - representing an #include line
+# *   CppBlock - a whole file or #if/#elif/#else block; contains a list of snippets
+# *   OrdinaryCode - representing lines of non-#include-relevant code
+
+
+def read_file(f):
+    block_stack = [CppBlock()]
+
+    # Extract the #include statements as a tree of snippets.
+    for linenum, line in enumerate(f, start=1):
+        if line.lstrip().startswith("#"):
+            # Look for a |#include "..."| line.
+            m = re.match(r'(\s*#\s*include\s+)"([^"]*)"(.*)', line)
+            if m is not None:
+                prefix, inclname, suffix = m.groups()
+                block_stack[-1].kids.append(
+                    Include(prefix, inclname, suffix, linenum, is_system=False)
+                )
+                continue
+
+            # Look for a |#include <...>| line.
+            m = re.match(r"(\s*#\s*include\s+)<([^>]*)>(.*)", line)
+            if m is not None:
+                prefix, inclname, suffix = m.groups()
+                block_stack[-1].kids.append(
+                    Include(prefix, inclname, suffix, linenum, is_system=True)
+                )
+                continue
+
+            # Look for a |#{if,ifdef,ifndef}| line.
+            m = re.match(r"\s*#\s*(if|ifdef|ifndef)\b", line)
+            if m is not None:
+                # Open a new block.
+                new_block = CppBlock(line)
+                block_stack[-1].kids.append(new_block)
+                block_stack.append(new_block)
+                continue
+
+            # Look for a |#{elif,else}| line.
+            m = re.match(r"\s*#\s*(elif|else)\b", line)
+            if m is not None:
+                # Close the current block, and open an adjacent one.
+                block_stack.pop()
+                new_block = CppBlock(line)
+                block_stack[-1].kids.append(new_block)
+                block_stack.append(new_block)
+                continue
+
+            # Look for a |#endif| line.
+            m = re.match(r"\s*#\s*endif\b", line)
+            if m is not None:
+                # Close the current block.
+                block_stack.pop().end = line
+                if len(block_stack) == 0:
+                    raise ValueError("#endif without #if at line " + str(linenum))
+                continue
+
+        # Otherwise, we have an ordinary line.
+        block_stack[-1].append_ordinary_line(line)
+
+    if len(block_stack) > 1:
+        raise ValueError("unmatched #if")
+    return block_stack[-1]
+
+
+def check_file(
+    filename, inclname, file_kind, code, all_inclnames, included_h_inclnames
+):
+    def check_include_statement(include):
+        """Check the style of a single #include statement."""
+
+        if include.is_system:
+            # Check it is not a known local file (in which case it's probably a system header).
+            if (
+                include.inclname in included_inclnames_to_ignore
+                or include.inclname in all_inclnames
+            ):
+                error(
+                    filename,
+                    include.linenum,
+                    include.quote() + " should be included using",
+                    'the #include "..." form',
+                )
+
+        else:
+            msg = deprecated_inclnames.get(include.inclname)
+            if msg:
+                error(
+                    filename,
+                    include.linenum,
+                    include.quote() + " is deprecated: " + msg,
+                )
+
+            if file_kind == FileKind.H or file_kind == FileKind.INL_H:
+                msg = deprecated_inclnames_in_header.get(include.inclname)
+                if msg and filename not in deprecated_inclnames_in_header_excludes:
+                    error(
+                        filename,
+                        include.linenum,
+                        include.quote() + " is deprecated: " + msg,
+                    )
+
+            if include.inclname not in included_inclnames_to_ignore:
+                included_kind = FileKind.get(include.inclname)
+
+                # Check the #include path has the correct form.
+                if include.inclname not in all_inclnames:
+                    error(
+                        filename,
+                        include.linenum,
+                        include.quote() + " is included using the wrong path;",
+                        "did you forget a prefix, or is the file not yet committed?",
+                    )
+
+                # Record inclusions of .h files for cycle detection later.
+                # (Exclude .tbl and .msg files.)
+                elif included_kind == FileKind.H or included_kind == FileKind.INL_H:
+                    included_h_inclnames.add(include.inclname)
+
+                # Check a H file doesn't #include an INL_H file.
+                if file_kind == FileKind.H and included_kind == FileKind.INL_H:
+                    error(
+                        filename,
+                        include.linenum,
+                        "vanilla header includes an inline-header file "
+                        + include.quote(),
+                    )
+
+                # Check a file doesn't #include itself.  (We do this here because the cycle
+                # detection below doesn't detect this case.)
+                if inclname == include.inclname:
+                    error(filename, include.linenum, "the file includes itself")
+
+    def check_includes_order(include1, include2):
+        """Check the ordering of two #include statements."""
+
+        if (
+            include1.inclname in oddly_ordered_inclnames
+            or include2.inclname in oddly_ordered_inclnames
+        ):
+            return
+
+        section1 = include1.section(inclname)
+        section2 = include2.section(inclname)
+        if (section1 > section2) or (
+            (section1 == section2)
+            and (include1.inclname.lower() > include2.inclname.lower())
+        ):
+            error(
+                filename,
+                str(include1.linenum) + ":" + str(include2.linenum),
+                include1.quote() + " should be included after " + include2.quote(),
+            )
+
+    # Check the extracted #include statements, both individually, and the ordering of
+    # adjacent pairs that live in the same block.
+    def pair_traverse(prev, this):
+        if isinstance(this, Include):
+            check_include_statement(this)
+            if isinstance(prev, Include):
+                check_includes_order(prev, this)
+        else:
+            kids = this.style_relevant_kids()
+            for prev2, this2 in zip([None] + kids[0:-1], kids):
+                pair_traverse(prev2, this2)
+
+    pair_traverse(None, code)
+
+
+def find_cycles(all_inclnames, edges):
+    """Find and draw any cycles."""
+
+    SCCs = tarjan(all_inclnames, edges)
+
+    # The various sorted() calls below ensure the output is deterministic.
+
+    def draw_SCC(c):
+        cset = set(c)
+        drawn = set()
+
+        def draw(v, indent):
+            out("   " * indent + ("-> " if indent else "   ") + v)
+            if v in drawn:
+                return
+            drawn.add(v)
+            for succ in sorted(edges[v]):
+                if succ in cset:
+                    draw(succ, indent + 1)
+
+        draw(sorted(c)[0], 0)
+        out("")
+
+    have_drawn_an_SCC = False
+    for scc in sorted(SCCs):
+        if len(scc) != 1:
+            if not have_drawn_an_SCC:
+                error("(multiple files)", None, "header files form one or more cycles")
+                have_drawn_an_SCC = True
+
+            draw_SCC(scc)
+
+
+# Tarjan's algorithm for finding the strongly connected components (SCCs) of a graph.
+# https://en.wikipedia.org/wiki/Tarjan%27s_strongly_connected_components_algorithm
+def tarjan(V, E):
+    vertex_index = {}
+    vertex_lowlink = {}
+    index = 0
+    S = []
+    all_SCCs = []
+
+    def strongconnect(v, index):
+        # Set the depth index for v to the smallest unused index
+        vertex_index[v] = index
+        vertex_lowlink[v] = index
+        index += 1
+        S.append(v)
+
+        # Consider successors of v
+        for w in E[v]:
+            if w not in vertex_index:
+                # Successor w has not yet been visited; recurse on it
+                index = strongconnect(w, index)
+                vertex_lowlink[v] = min(vertex_lowlink[v], vertex_lowlink[w])
+            elif w in S:
+                # Successor w is in stack S and hence in the current SCC
+                vertex_lowlink[v] = min(vertex_lowlink[v], vertex_index[w])
+
+        # If v is a root node, pop the stack and generate an SCC
+        if vertex_lowlink[v] == vertex_index[v]:
+            i = S.index(v)
+            scc = S[i:]
+            del S[i:]
+            all_SCCs.append(scc)
+
+        return index
+
+    for v in V:
+        if v not in vertex_index:
+            index = strongconnect(v, index)
+
+    return all_SCCs
+
+
+def main():
+    if sys.argv[1:] == ["--fixup"]:
+        # Sort #include directives in-place.  Fixup mode doesn't solve
+        # all possible silliness that the script checks for; it's just a
+        # hack for the common case where renaming a header causes style
+        # errors.
+        fixup = True
+    elif sys.argv[1:] == []:
+        fixup = False
+    else:
+        print(
+            "TEST-UNEXPECTED-FAIL | check_spidermonkey_style.py | unexpected command "
+            "line options: " + repr(sys.argv[1:])
+        )
+        sys.exit(1)
+
+    ok = check_style(fixup)
+
+    if ok:
+        print("TEST-PASS | check_spidermonkey_style.py | ok")
+    else:
+        print(
+            "TEST-UNEXPECTED-FAIL | check_spidermonkey_style.py | "
+            + "actual output does not match expected output;  diff is above."
+        )
+        print(
+            "TEST-UNEXPECTED-FAIL | check_spidermonkey_style.py | "
+            + "Hint: If the problem is that you renamed a header, and many #includes "
+            + "are no longer in alphabetical order, commit your work and then try "
+            + "`check_spidermonkey_style.py --fixup`. "
+            + "You need to commit first because --fixup modifies your files in place."
+        )
+
+    sys.exit(0 if ok else 1)
+
+
+if __name__ == "__main__":
+    main()