xref: /linux/tools/lib/python/kdoc/kdoc_parser.py (revision b211a30690f8263b79f30b6b1770ffe216fa378c)
1#!/usr/bin/env python3
2# SPDX-License-Identifier: GPL-2.0
3# Copyright(c) 2025: Mauro Carvalho Chehab <mchehab@kernel.org>.
4#
5# pylint: disable=C0301,C0302,R0904,R0912,R0913,R0914,R0915,R0917,R1702
6
7"""
8Classes and functions related to reading a C language source or header FILE
9and extract embedded documentation comments from it.
10"""
11
12import sys
13import re
14from pprint import pformat
15
16from kdoc.kdoc_re import NestedMatch, KernRe
17from kdoc.kdoc_item import KdocItem
18
19#
20# Regular expressions used to parse kernel-doc markups at KernelDoc class.
21#
22# Let's declare them in lowercase outside any class to make it easier to
23# convert from the Perl script.
24#
25# As those are evaluated at the beginning, no need to cache them
26#
27
28# Allow whitespace at end of comment start.
29doc_start = KernRe(r'^/\*\*\s*$', cache=False)
30
31doc_end = KernRe(r'\*/', cache=False)
32doc_com = KernRe(r'\s*\*\s*', cache=False)
33doc_com_body = KernRe(r'\s*\* ?', cache=False)
34doc_decl = doc_com + KernRe(r'(\w+)', cache=False)
35
36# @params and a strictly limited set of supported section names
37# Specifically:
38#   Match @word:
39#         @...:
40#         @{section-name}:
41# while trying to not match literal block starts like "example::"
42#
43known_section_names = 'description|context|returns?|notes?|examples?'
44known_sections = KernRe(known_section_names, flags = re.I)
45doc_sect = doc_com + \
46    KernRe(r'\s*(@[.\w]+|@\.\.\.|' + known_section_names + r')\s*:([^:].*)?$',
47           flags=re.I, cache=False)
48
49doc_content = doc_com_body + KernRe(r'(.*)', cache=False)
50doc_inline_start = KernRe(r'^\s*/\*\*\s*$', cache=False)
51doc_inline_sect = KernRe(r'\s*\*\s*(@\s*[\w][\w\.]*\s*):(.*)', cache=False)
52doc_inline_end = KernRe(r'^\s*\*/\s*$', cache=False)
53doc_inline_oneline = KernRe(r'^\s*/\*\*\s*(@\s*[\w][\w\.]*\s*):\s*(.*)\s*\*/\s*$', cache=False)
54
55export_symbol = KernRe(r'^\s*EXPORT_SYMBOL(_GPL)?\s*\(\s*(\w+)\s*\)\s*', cache=False)
56export_symbol_ns = KernRe(r'^\s*EXPORT_SYMBOL_NS(_GPL)?\s*\(\s*(\w+)\s*,\s*"\S+"\)\s*', cache=False)
57
58type_param = KernRe(r"@(\w*((\.\w+)|(->\w+))*(\.\.\.)?)", cache=False)
59
60#
61# Tests for the beginning of a kerneldoc block in its various forms.
62#
63doc_block = doc_com + KernRe(r'DOC:\s*(.*)?', cache=False)
64doc_begin_data = KernRe(r"^\s*\*?\s*(struct|union|enum|typedef|var)\b\s*(\w*)", cache = False)
65doc_begin_func = KernRe(str(doc_com) +			# initial " * '
66                        r"(?:\w+\s*\*\s*)?" + 		# type (not captured)
67                        r'(?:define\s+)?' + 		# possible "define" (not captured)
68                        r'(\w+)\s*(?:\(\w*\))?\s*' +	# name and optional "(...)"
69                        r'(?:[-:].*)?$',		# description (not captured)
70                        cache = False)
71
72#
73# Here begins a long set of transformations to turn structure member prefixes
74# and macro invocations into something we can parse and generate kdoc for.
75#
76struct_args_pattern = r'([^,)]+)'
77
78struct_xforms = [
79    # Strip attributes
80    (KernRe(r"__attribute__\s*\(\([a-z0-9,_\*\s\(\)]*\)\)", flags=re.I | re.S, cache=False), ' '),
81    (KernRe(r'\s*__aligned\s*\([^;]*\)', re.S), ' '),
82    (KernRe(r'\s*__counted_by\s*\([^;]*\)', re.S), ' '),
83    (KernRe(r'\s*__counted_by_(le|be)\s*\([^;]*\)', re.S), ' '),
84    (KernRe(r'\s*__packed\s*', re.S), ' '),
85    (KernRe(r'\s*CRYPTO_MINALIGN_ATTR', re.S), ' '),
86    (KernRe(r'\s*__private', re.S), ' '),
87    (KernRe(r'\s*__rcu', re.S), ' '),
88    (KernRe(r'\s*____cacheline_aligned_in_smp', re.S), ' '),
89    (KernRe(r'\s*____cacheline_aligned', re.S), ' '),
90    (KernRe(r'\s*__cacheline_group_(begin|end)\([^\)]+\);'), ''),
91    #
92    # Unwrap struct_group macros based on this definition:
93    # __struct_group(TAG, NAME, ATTRS, MEMBERS...)
94    # which has variants like: struct_group(NAME, MEMBERS...)
95    # Only MEMBERS arguments require documentation.
96    #
97    # Parsing them happens on two steps:
98    #
99    # 1. drop struct group arguments that aren't at MEMBERS,
100    #    storing them as STRUCT_GROUP(MEMBERS)
101    #
102    # 2. remove STRUCT_GROUP() ancillary macro.
103    #
104    # The original logic used to remove STRUCT_GROUP() using an
105    # advanced regex:
106    #
107    #   \bSTRUCT_GROUP(\(((?:(?>[^)(]+)|(?1))*)\))[^;]*;
108    #
109    # with two patterns that are incompatible with
110    # Python re module, as it has:
111    #
112    #   - a recursive pattern: (?1)
113    #   - an atomic grouping: (?>...)
114    #
115    # I tried a simpler version: but it didn't work either:
116    #   \bSTRUCT_GROUP\(([^\)]+)\)[^;]*;
117    #
118    # As it doesn't properly match the end parenthesis on some cases.
119    #
120    # So, a better solution was crafted: there's now a NestedMatch
121    # class that ensures that delimiters after a search are properly
122    # matched. So, the implementation to drop STRUCT_GROUP() will be
123    # handled in separate.
124    #
125    (KernRe(r'\bstruct_group\s*\(([^,]*,)', re.S), r'STRUCT_GROUP('),
126    (KernRe(r'\bstruct_group_attr\s*\(([^,]*,){2}', re.S), r'STRUCT_GROUP('),
127    (KernRe(r'\bstruct_group_tagged\s*\(([^,]*),([^,]*),', re.S), r'struct \1 \2; STRUCT_GROUP('),
128    (KernRe(r'\b__struct_group\s*\(([^,]*,){3}', re.S), r'STRUCT_GROUP('),
129    #
130    # Replace macros
131    #
132    # TODO: use NestedMatch for FOO($1, $2, ...) matches
133    #
134    # it is better to also move those to the NestedMatch logic,
135    # to ensure that parentheses will be properly matched.
136    #
137    (KernRe(r'__ETHTOOL_DECLARE_LINK_MODE_MASK\s*\(([^\)]+)\)', re.S),
138     r'DECLARE_BITMAP(\1, __ETHTOOL_LINK_MODE_MASK_NBITS)'),
139    (KernRe(r'DECLARE_PHY_INTERFACE_MASK\s*\(([^\)]+)\)', re.S),
140     r'DECLARE_BITMAP(\1, PHY_INTERFACE_MODE_MAX)'),
141    (KernRe(r'DECLARE_BITMAP\s*\(' + struct_args_pattern + r',\s*' + struct_args_pattern + r'\)',
142            re.S), r'unsigned long \1[BITS_TO_LONGS(\2)]'),
143    (KernRe(r'DECLARE_HASHTABLE\s*\(' + struct_args_pattern + r',\s*' + struct_args_pattern + r'\)',
144            re.S), r'unsigned long \1[1 << ((\2) - 1)]'),
145    (KernRe(r'DECLARE_KFIFO\s*\(' + struct_args_pattern + r',\s*' + struct_args_pattern +
146            r',\s*' + struct_args_pattern + r'\)', re.S), r'\2 *\1'),
147    (KernRe(r'DECLARE_KFIFO_PTR\s*\(' + struct_args_pattern + r',\s*' +
148            struct_args_pattern + r'\)', re.S), r'\2 *\1'),
149    (KernRe(r'(?:__)?DECLARE_FLEX_ARRAY\s*\(' + struct_args_pattern + r',\s*' +
150            struct_args_pattern + r'\)', re.S), r'\1 \2[]'),
151    (KernRe(r'DEFINE_DMA_UNMAP_ADDR\s*\(' + struct_args_pattern + r'\)', re.S), r'dma_addr_t \1'),
152    (KernRe(r'DEFINE_DMA_UNMAP_LEN\s*\(' + struct_args_pattern + r'\)', re.S), r'__u32 \1'),
153]
154#
155# Regexes here are guaranteed to have the end delimiter matching
156# the start delimiter. Yet, right now, only one replace group
157# is allowed.
158#
159struct_nested_prefixes = [
160    (re.compile(r'\bSTRUCT_GROUP\('), r'\1'),
161]
162
163#
164# Transforms for function prototypes
165#
166function_xforms  = [
167    (KernRe(r"^static +"), ""),
168    (KernRe(r"^extern +"), ""),
169    (KernRe(r"^asmlinkage +"), ""),
170    (KernRe(r"^inline +"), ""),
171    (KernRe(r"^__inline__ +"), ""),
172    (KernRe(r"^__inline +"), ""),
173    (KernRe(r"^__always_inline +"), ""),
174    (KernRe(r"^noinline +"), ""),
175    (KernRe(r"^__FORTIFY_INLINE +"), ""),
176    (KernRe(r"__init +"), ""),
177    (KernRe(r"__init_or_module +"), ""),
178    (KernRe(r"__exit +"), ""),
179    (KernRe(r"__deprecated +"), ""),
180    (KernRe(r"__flatten +"), ""),
181    (KernRe(r"__meminit +"), ""),
182    (KernRe(r"__must_check +"), ""),
183    (KernRe(r"__weak +"), ""),
184    (KernRe(r"__sched +"), ""),
185    (KernRe(r"_noprof"), ""),
186    (KernRe(r"__always_unused *"), ""),
187    (KernRe(r"__printf\s*\(\s*\d*\s*,\s*\d*\s*\) +"), ""),
188    (KernRe(r"__(?:re)?alloc_size\s*\(\s*\d+\s*(?:,\s*\d+\s*)?\) +"), ""),
189    (KernRe(r"__diagnose_as\s*\(\s*\S+\s*(?:,\s*\d+\s*)*\) +"), ""),
190    (KernRe(r"DECL_BUCKET_PARAMS\s*\(\s*(\S+)\s*,\s*(\S+)\s*\)"), r"\1, \2"),
191    (KernRe(r"__attribute_const__ +"), ""),
192    (KernRe(r"__attribute__\s*\(\((?:[\w\s]+(?:\([^)]*\))?\s*,?)+\)\)\s+"), ""),
193]
194
195#
196# Ancillary functions
197#
198
199def apply_transforms(xforms, text):
200    """
201    Apply a set of transforms to a block of text.
202    """
203    for search, subst in xforms:
204        text = search.sub(subst, text)
205    return text
206
207multi_space = KernRe(r'\s\s+')
208def trim_whitespace(s):
209    """
210    A little helper to get rid of excess white space.
211    """
212    return multi_space.sub(' ', s.strip())
213
214def trim_private_members(text):
215    """
216    Remove ``struct``/``enum`` members that have been marked "private".
217    """
218    # First look for a "public:" block that ends a private region, then
219    # handle the "private until the end" case.
220    #
221    text = KernRe(r'/\*\s*private:.*?/\*\s*public:.*?\*/', flags=re.S).sub('', text)
222    text = KernRe(r'/\*\s*private:.*', flags=re.S).sub('', text)
223    #
224    # We needed the comments to do the above, but now we can take them out.
225    #
226    return KernRe(r'\s*/\*.*?\*/\s*', flags=re.S).sub('', text).strip()
227
228class state:
229    """
230    States used by the parser's state machine.
231    """
232
233    # Parser states
234    NORMAL        = 0        #: Normal code.
235    NAME          = 1        #: Looking for function name.
236    DECLARATION   = 2        #: We have seen a declaration which might not be done.
237    BODY          = 3        #: The body of the comment.
238    SPECIAL_SECTION = 4      #: Doc section ending with a blank line.
239    PROTO         = 5        #: Scanning prototype.
240    DOCBLOCK      = 6        #: Documentation block.
241    INLINE_NAME   = 7        #: Gathering doc outside main block.
242    INLINE_TEXT   = 8	     #: Reading the body of inline docs.
243
244    #: Names for each parser state.
245    name = [
246        "NORMAL",
247        "NAME",
248        "DECLARATION",
249        "BODY",
250        "SPECIAL_SECTION",
251        "PROTO",
252        "DOCBLOCK",
253        "INLINE_NAME",
254        "INLINE_TEXT",
255    ]
256
257
258SECTION_DEFAULT = "Description"  #: Default section.
259
260class KernelEntry:
261    """
262    Encapsulates a Kernel documentation entry.
263    """
264
265    def __init__(self, config, fname, ln):
266        self.config = config
267        self.fname = fname
268
269        self._contents = []
270        self.prototype = ""
271
272        self.warnings = []
273
274        self.parameterlist = []
275        self.parameterdescs = {}
276        self.parametertypes = {}
277        self.parameterdesc_start_lines = {}
278
279        self.section_start_lines = {}
280        self.sections = {}
281
282        self.anon_struct_union = False
283
284        self.leading_space = None
285
286        self.fname = fname
287
288        # State flags
289        self.brcount = 0
290        self.declaration_start_line = ln + 1
291
292    #
293    # Management of section contents
294    #
295    def add_text(self, text):
296        """Add a new text to the entry contents list."""
297        self._contents.append(text)
298
299    def contents(self):
300        """Returns a string with all content texts that were added."""
301        return '\n'.join(self._contents) + '\n'
302
303    # TODO: rename to emit_message after removal of kernel-doc.pl
304    def emit_msg(self, ln, msg, *, warning=True):
305        """Emit a message."""
306
307        log_msg = f"{self.fname}:{ln} {msg}"
308
309        if not warning:
310            self.config.log.info(log_msg)
311            return
312
313        # Delegate warning output to output logic, as this way it
314        # will report warnings/info only for symbols that are output
315
316        self.warnings.append(log_msg)
317        return
318
319    def begin_section(self, line_no, title = SECTION_DEFAULT, dump = False):
320        """
321        Begin a new section.
322        """
323        if dump:
324            self.dump_section(start_new = True)
325        self.section = title
326        self.new_start_line = line_no
327
328    def dump_section(self, start_new=True):
329        """
330        Dumps section contents to arrays/hashes intended for that purpose.
331        """
332        #
333        # If we have accumulated no contents in the default ("description")
334        # section, don't bother.
335        #
336        if self.section == SECTION_DEFAULT and not self._contents:
337            return
338        name = self.section
339        contents = self.contents()
340
341        if type_param.match(name):
342            name = type_param.group(1)
343
344            self.parameterdescs[name] = contents
345            self.parameterdesc_start_lines[name] = self.new_start_line
346
347            self.new_start_line = 0
348
349        else:
350            if name in self.sections and self.sections[name] != "":
351                # Only warn on user-specified duplicate section names
352                if name != SECTION_DEFAULT:
353                    self.emit_msg(self.new_start_line,
354                                  f"duplicate section name '{name}'")
355                # Treat as a new paragraph - add a blank line
356                self.sections[name] += '\n' + contents
357            else:
358                self.sections[name] = contents
359                self.section_start_lines[name] = self.new_start_line
360                self.new_start_line = 0
361
362#        self.config.log.debug("Section: %s : %s", name, pformat(vars(self)))
363
364        if start_new:
365            self.section = SECTION_DEFAULT
366            self._contents = []
367
368python_warning = False
369
370class KernelDoc:
371    """
372    Read a C language source or header FILE and extract embedded
373    documentation comments.
374    """
375
376    #: Name of context section.
377    section_context = "Context"
378
379    #: Name of return section.
380    section_return = "Return"
381
382    #: String to write when a parameter is not described.
383    undescribed = "-- undescribed --"
384
385    def __init__(self, config, fname):
386        """Initialize internal variables"""
387
388        self.fname = fname
389        self.config = config
390
391        # Initial state for the state machines
392        self.state = state.NORMAL
393
394        # Store entry currently being processed
395        self.entry = None
396
397        # Place all potential outputs into an array
398        self.entries = []
399
400        #
401        # We need Python 3.7 for its "dicts remember the insertion
402        # order" guarantee
403        #
404        global python_warning
405        if (not python_warning and
406            sys.version_info.major == 3 and sys.version_info.minor < 7):
407
408            self.emit_msg(0,
409                          'Python 3.7 or later is required for correct results')
410            python_warning = True
411
412    def emit_msg(self, ln, msg, *, warning=True):
413        """Emit a message"""
414
415        if self.entry:
416            self.entry.emit_msg(ln, msg, warning=warning)
417            return
418
419        log_msg = f"{self.fname}:{ln} {msg}"
420
421        if warning:
422            self.config.log.warning(log_msg)
423        else:
424            self.config.log.info(log_msg)
425
426    def dump_section(self, start_new=True):
427        """
428        Dump section contents to arrays/hashes intended for that purpose.
429        """
430
431        if self.entry:
432            self.entry.dump_section(start_new)
433
434    # TODO: rename it to store_declaration after removal of kernel-doc.pl
435    def output_declaration(self, dtype, name, **args):
436        """
437        Store the entry into an entry array.
438
439        The actual output and output filters will be handled elsewhere.
440        """
441
442        item = KdocItem(name, self.fname, dtype,
443                        self.entry.declaration_start_line, **args)
444        item.warnings = self.entry.warnings
445
446        # Drop empty sections
447        # TODO: improve empty sections logic to emit warnings
448        sections = self.entry.sections
449        for section in ["Description", "Return"]:
450            if section in sections and not sections[section].rstrip():
451                del sections[section]
452        item.set_sections(sections, self.entry.section_start_lines)
453        item.set_params(self.entry.parameterlist, self.entry.parameterdescs,
454                        self.entry.parametertypes,
455                        self.entry.parameterdesc_start_lines)
456        self.entries.append(item)
457
458        self.config.log.debug("Output: %s:%s = %s", dtype, name, pformat(args))
459
460    def emit_unused_warnings(self):
461        """
462        When the parser fails to produce a valid entry, it places some
463        warnings under `entry.warnings` that will be discarded when resetting
464        the state.
465
466        Ensure that those warnings are not lost.
467
468        .. note::
469
470              Because we are calling `config.warning()` here, those
471              warnings are not filtered by the `-W` parameters: they will all
472              be produced even when `-Wreturn`, `-Wshort-desc`, and/or
473              `-Wcontents-before-sections` are used.
474
475              Allowing those warnings to be filtered is complex, because it
476              would require storing them in a buffer and then filtering them
477              during the output step of the code, depending on the
478              selected symbols.
479        """
480        if self.entry and self.entry not in self.entries:
481            for log_msg in self.entry.warnings:
482                self.config.warning(log_msg)
483
484    def reset_state(self, ln):
485        """
486        Ancillary routine to create a new entry. It initializes all
487        variables used by the state machine.
488        """
489
490        self.emit_unused_warnings()
491
492        self.entry = KernelEntry(self.config, self.fname, ln)
493
494        # State flags
495        self.state = state.NORMAL
496
497    def push_parameter(self, ln, decl_type, param, dtype,
498                       org_arg, declaration_name):
499        """
500        Store parameters and their descriptions at self.entry.
501        """
502
503        if self.entry.anon_struct_union and dtype == "" and param == "}":
504            return  # Ignore the ending }; from anonymous struct/union
505
506        self.entry.anon_struct_union = False
507
508        param = KernRe(r'[\[\)].*').sub('', param, count=1)
509
510        #
511        # Look at various "anonymous type" cases.
512        #
513        if dtype == '':
514            if param.endswith("..."):
515                if len(param) > 3: # there is a name provided, use that
516                    param = param[:-3]
517                if not self.entry.parameterdescs.get(param):
518                    self.entry.parameterdescs[param] = "variable arguments"
519
520            elif (not param) or param == "void":
521                param = "void"
522                self.entry.parameterdescs[param] = "no arguments"
523
524            elif param in ["struct", "union"]:
525                # Handle unnamed (anonymous) union or struct
526                dtype = param
527                param = "{unnamed_" + param + "}"
528                self.entry.parameterdescs[param] = "anonymous\n"
529                self.entry.anon_struct_union = True
530
531        # Warn if parameter has no description
532        # (but ignore ones starting with # as these are not parameters
533        # but inline preprocessor statements)
534        if param not in self.entry.parameterdescs and not param.startswith("#"):
535            self.entry.parameterdescs[param] = self.undescribed
536
537            if "." not in param:
538                if decl_type == 'function':
539                    dname = f"{decl_type} parameter"
540                else:
541                    dname = f"{decl_type} member"
542
543                self.emit_msg(ln,
544                              f"{dname} '{param}' not described in '{declaration_name}'")
545
546        # Strip spaces from param so that it is one continuous string on
547        # parameterlist. This fixes a problem where check_sections()
548        # cannot find a parameter like "addr[6 + 2]" because it actually
549        # appears as "addr[6", "+", "2]" on the parameter list.
550        # However, it's better to maintain the param string unchanged for
551        # output, so just weaken the string compare in check_sections()
552        # to ignore "[blah" in a parameter string.
553
554        self.entry.parameterlist.append(param)
555        org_arg = KernRe(r'\s\s+').sub(' ', org_arg)
556        self.entry.parametertypes[param] = org_arg
557
558
559    def create_parameter_list(self, ln, decl_type, args,
560                              splitter, declaration_name):
561        """
562        Creates a list of parameters, storing them at self.entry.
563        """
564
565        # temporarily replace all commas inside function pointer definition
566        arg_expr = KernRe(r'(\([^\),]+),')
567        while arg_expr.search(args):
568            args = arg_expr.sub(r"\1#", args)
569
570        for arg in args.split(splitter):
571            # Ignore argument attributes
572            arg = KernRe(r'\sPOS0?\s').sub(' ', arg)
573
574            # Strip leading/trailing spaces
575            arg = arg.strip()
576            arg = KernRe(r'\s+').sub(' ', arg, count=1)
577
578            if arg.startswith('#'):
579                # Treat preprocessor directive as a typeless variable just to fill
580                # corresponding data structures "correctly". Catch it later in
581                # output_* subs.
582
583                # Treat preprocessor directive as a typeless variable
584                self.push_parameter(ln, decl_type, arg, "",
585                                    "", declaration_name)
586            #
587            # The pointer-to-function case.
588            #
589            elif KernRe(r'\(.+\)\s*\(').search(arg):
590                arg = arg.replace('#', ',')
591                r = KernRe(r'[^\(]+\(\*?\s*'  # Everything up to "(*"
592                           r'([\w\[\].]*)'    # Capture the name and possible [array]
593                           r'\s*\)')	      # Make sure the trailing ")" is there
594                if r.match(arg):
595                    param = r.group(1)
596                else:
597                    self.emit_msg(ln, f"Invalid param: {arg}")
598                    param = arg
599                dtype = arg.replace(param, '')
600                self.push_parameter(ln, decl_type, param, dtype, arg, declaration_name)
601            #
602            # The array-of-pointers case.  Dig the parameter name out from the middle
603            # of the declaration.
604            #
605            elif KernRe(r'\(.+\)\s*\[').search(arg):
606                r = KernRe(r'[^\(]+\(\s*\*\s*'		# Up to "(" and maybe "*"
607                           r'([\w.]*?)'			# The actual pointer name
608                           r'\s*(\[\s*\w+\s*\]\s*)*\)') # The [array portion]
609                if r.match(arg):
610                    param = r.group(1)
611                else:
612                    self.emit_msg(ln, f"Invalid param: {arg}")
613                    param = arg
614                dtype = arg.replace(param, '')
615                self.push_parameter(ln, decl_type, param, dtype, arg, declaration_name)
616            elif arg:
617                #
618                # Clean up extraneous spaces and split the string at commas; the first
619                # element of the resulting list will also include the type information.
620                #
621                arg = KernRe(r'\s*:\s*').sub(":", arg)
622                arg = KernRe(r'\s*\[').sub('[', arg)
623                args = KernRe(r'\s*,\s*').split(arg)
624                args[0] = re.sub(r'(\*+)\s*', r' \1', args[0])
625                #
626                # args[0] has a string of "type a".  If "a" includes an [array]
627                # declaration, we want to not be fooled by any white space inside
628                # the brackets, so detect and handle that case specially.
629                #
630                r = KernRe(r'^([^[\]]*\s+)(.*)$')
631                if r.match(args[0]):
632                    args[0] = r.group(2)
633                    dtype = r.group(1)
634                else:
635                    # No space in args[0]; this seems wrong but preserves previous behavior
636                    dtype = ''
637
638                bitfield_re = KernRe(r'(.*?):(\w+)')
639                for param in args:
640                    #
641                    # For pointers, shift the star(s) from the variable name to the
642                    # type declaration.
643                    #
644                    r = KernRe(r'^(\*+)\s*(.*)')
645                    if r.match(param):
646                        self.push_parameter(ln, decl_type, r.group(2),
647                                            f"{dtype} {r.group(1)}",
648                                            arg, declaration_name)
649                    #
650                    # Perform a similar shift for bitfields.
651                    #
652                    elif bitfield_re.search(param):
653                        if dtype != "":  # Skip unnamed bit-fields
654                            self.push_parameter(ln, decl_type, bitfield_re.group(1),
655                                                f"{dtype}:{bitfield_re.group(2)}",
656                                                arg, declaration_name)
657                    else:
658                        self.push_parameter(ln, decl_type, param, dtype,
659                                            arg, declaration_name)
660
661    def check_sections(self, ln, decl_name, decl_type):
662        """
663        Check for errors inside sections, emitting warnings if not found
664        parameters are described.
665        """
666        for section in self.entry.sections:
667            if section not in self.entry.parameterlist and \
668               not known_sections.search(section):
669                if decl_type == 'function':
670                    dname = f"{decl_type} parameter"
671                else:
672                    dname = f"{decl_type} member"
673                self.emit_msg(ln,
674                              f"Excess {dname} '{section}' description in '{decl_name}'")
675
676    def check_return_section(self, ln, declaration_name, return_type):
677        """
678        If the function doesn't return void, warns about the lack of a
679        return description.
680        """
681
682        if not self.config.wreturn:
683            return
684
685        # Ignore an empty return type (It's a macro)
686        # Ignore functions with a "void" return type (but not "void *")
687        if not return_type or KernRe(r'void\s*\w*\s*$').search(return_type):
688            return
689
690        if not self.entry.sections.get("Return", None):
691            self.emit_msg(ln,
692                          f"No description found for return value of '{declaration_name}'")
693
694    def split_struct_proto(self, proto):
695        """
696        Split apart a structure prototype; returns (struct|union, name,
697        members) or ``None``.
698        """
699
700        type_pattern = r'(struct|union)'
701        qualifiers = [
702            "__attribute__",
703            "__packed",
704            "__aligned",
705            "____cacheline_aligned_in_smp",
706            "____cacheline_aligned",
707        ]
708        definition_body = r'\{(.*)\}\s*' + "(?:" + '|'.join(qualifiers) + ")?"
709
710        r = KernRe(type_pattern + r'\s+(\w+)\s*' + definition_body)
711        if r.search(proto):
712            return (r.group(1), r.group(2), r.group(3))
713        else:
714            r = KernRe(r'typedef\s+' + type_pattern + r'\s*' + definition_body + r'\s*(\w+)\s*;')
715            if r.search(proto):
716                return (r.group(1), r.group(3), r.group(2))
717        return None
718
719    def rewrite_struct_members(self, members):
720        """
721        Process ``struct``/``union`` members from the most deeply nested
722        outward.
723
724        Rewrite the members of a ``struct`` or ``union`` for easier formatting
725        later on. Among other things, this function will turn a member like::
726
727          struct { inner_members; } foo;
728
729        into::
730
731          struct foo; inner_members;
732        """
733
734        #
735        # The trick is in the ``^{`` below - it prevents a match of an outer
736        # ``struct``/``union`` until the inner one has been munged
737        # (removing the ``{`` in the process).
738        #
739        struct_members = KernRe(r'(struct|union)'   # 0: declaration type
740                                r'([^\{\};]+)' 	    # 1: possible name
741                                r'(\{)'
742                                r'([^\{\}]*)'       # 3: Contents of declaration
743                                r'(\})'
744                                r'([^\{\};]*)(;)')  # 5: Remaining stuff after declaration
745        tuples = struct_members.findall(members)
746        while tuples:
747            for t in tuples:
748                newmember = ""
749                oldmember = "".join(t) # Reconstruct the original formatting
750                dtype, name, lbr, content, rbr, rest, semi = t
751                #
752                # Pass through each field name, normalizing the form and formatting.
753                #
754                for s_id in rest.split(','):
755                    s_id = s_id.strip()
756                    newmember += f"{dtype} {s_id}; "
757                    #
758                    # Remove bitfield/array/pointer info, getting the bare name.
759                    #
760                    s_id = KernRe(r'[:\[].*').sub('', s_id)
761                    s_id = KernRe(r'^\s*\**(\S+)\s*').sub(r'\1', s_id)
762                    #
763                    # Pass through the members of this inner structure/union.
764                    #
765                    for arg in content.split(';'):
766                        arg = arg.strip()
767                        #
768                        # Look for (type)(*name)(args) - pointer to function
769                        #
770                        r = KernRe(r'^([^\(]+\(\*?\s*)([\w.]*)(\s*\).*)')
771                        if r.match(arg):
772                            dtype, name, extra = r.group(1), r.group(2), r.group(3)
773                            # Pointer-to-function
774                            if not s_id:
775                                # Anonymous struct/union
776                                newmember += f"{dtype}{name}{extra}; "
777                            else:
778                                newmember += f"{dtype}{s_id}.{name}{extra}; "
779                        #
780                        # Otherwise a non-function member.
781                        #
782                        else:
783                            #
784                            # Remove bitmap and array portions and spaces around commas
785                            #
786                            arg = KernRe(r':\s*\d+\s*').sub('', arg)
787                            arg = KernRe(r'\[.*\]').sub('', arg)
788                            arg = KernRe(r'\s*,\s*').sub(',', arg)
789                            #
790                            # Look for a normal decl - "type name[,name...]"
791                            #
792                            r = KernRe(r'(.*)\s+([\S+,]+)')
793                            if r.search(arg):
794                                for name in r.group(2).split(','):
795                                    name = KernRe(r'^\s*\**(\S+)\s*').sub(r'\1', name)
796                                    if not s_id:
797                                        # Anonymous struct/union
798                                        newmember += f"{r.group(1)} {name}; "
799                                    else:
800                                        newmember += f"{r.group(1)} {s_id}.{name}; "
801                            else:
802                                newmember += f"{arg}; "
803                #
804                # At the end of the s_id loop, replace the original declaration with
805                # the munged version.
806                #
807                members = members.replace(oldmember, newmember)
808            #
809            # End of the tuple loop - search again and see if there are outer members
810            # that now turn up.
811            #
812            tuples = struct_members.findall(members)
813        return members
814
815    def format_struct_decl(self, declaration):
816        """
817        Format the ``struct`` declaration into a standard form for inclusion
818        in the resulting docs.
819        """
820
821        #
822        # Insert newlines, get rid of extra spaces.
823        #
824        declaration = KernRe(r'([\{;])').sub(r'\1\n', declaration)
825        declaration = KernRe(r'\}\s+;').sub('};', declaration)
826        #
827        # Format inline enums with each member on its own line.
828        #
829        r = KernRe(r'(enum\s+\{[^\}]+),([^\n])')
830        while r.search(declaration):
831            declaration = r.sub(r'\1,\n\2', declaration)
832        #
833        # Now go through and supply the right number of tabs
834        # for each line.
835        #
836        def_args = declaration.split('\n')
837        level = 1
838        declaration = ""
839        for clause in def_args:
840            clause = KernRe(r'\s+').sub(' ', clause.strip(), count=1)
841            if clause:
842                if '}' in clause and level > 1:
843                    level -= 1
844                if not clause.startswith('#'):
845                    declaration += "\t" * level
846                declaration += "\t" + clause + "\n"
847                if "{" in clause and "}" not in clause:
848                    level += 1
849        return declaration
850
851
852    def dump_struct(self, ln, proto):
853        """
854        Store an entry for a ``struct`` or ``union``
855        """
856        #
857        # Do the basic parse to get the pieces of the declaration.
858        #
859        struct_parts = self.split_struct_proto(proto)
860        if not struct_parts:
861            self.emit_msg(ln, f"{proto} error: Cannot parse struct or union!")
862            return
863        decl_type, declaration_name, members = struct_parts
864
865        if self.entry.identifier != declaration_name:
866            self.emit_msg(ln, f"expecting prototype for {decl_type} {self.entry.identifier}. "
867                          f"Prototype was for {decl_type} {declaration_name} instead\n")
868            return
869        #
870        # Go through the list of members applying all of our transformations.
871        #
872        members = trim_private_members(members)
873        members = apply_transforms(struct_xforms, members)
874
875        nested = NestedMatch()
876        for search, sub in struct_nested_prefixes:
877            members = nested.sub(search, sub, members)
878        #
879        # Deal with embedded struct and union members, and drop enums entirely.
880        #
881        declaration = members
882        members = self.rewrite_struct_members(members)
883        members = re.sub(r'(\{[^\{\}]*\})', '', members)
884        #
885        # Output the result and we are done.
886        #
887        self.create_parameter_list(ln, decl_type, members, ';',
888                                   declaration_name)
889        self.check_sections(ln, declaration_name, decl_type)
890        self.output_declaration(decl_type, declaration_name,
891                                definition=self.format_struct_decl(declaration),
892                                purpose=self.entry.declaration_purpose)
893
894    def dump_enum(self, ln, proto):
895        """
896        Store an ``enum`` inside self.entries array.
897        """
898        #
899        # Strip preprocessor directives.  Note that this depends on the
900        # trailing semicolon we added in process_proto_type().
901        #
902        proto = KernRe(r'#\s*((define|ifdef|if)\s+|endif)[^;]*;', flags=re.S).sub('', proto)
903        #
904        # Parse out the name and members of the enum.  Typedef form first.
905        #
906        r = KernRe(r'typedef\s+enum\s*\{(.*)\}\s*(\w*)\s*;')
907        if r.search(proto):
908            declaration_name = r.group(2)
909            members = trim_private_members(r.group(1))
910        #
911        # Failing that, look for a straight enum
912        #
913        else:
914            r = KernRe(r'enum\s+(\w*)\s*\{(.*)\}')
915            if r.match(proto):
916                declaration_name = r.group(1)
917                members = trim_private_members(r.group(2))
918        #
919        # OK, this isn't going to work.
920        #
921            else:
922                self.emit_msg(ln, f"{proto}: error: Cannot parse enum!")
923                return
924        #
925        # Make sure we found what we were expecting.
926        #
927        if self.entry.identifier != declaration_name:
928            if self.entry.identifier == "":
929                self.emit_msg(ln,
930                              f"{proto}: wrong kernel-doc identifier on prototype")
931            else:
932                self.emit_msg(ln,
933                              f"expecting prototype for enum {self.entry.identifier}. "
934                              f"Prototype was for enum {declaration_name} instead")
935            return
936
937        if not declaration_name:
938            declaration_name = "(anonymous)"
939        #
940        # Parse out the name of each enum member, and verify that we
941        # have a description for it.
942        #
943        member_set = set()
944        members = KernRe(r'\([^;)]*\)').sub('', members)
945        for arg in members.split(','):
946            if not arg:
947                continue
948            arg = KernRe(r'^\s*(\w+).*').sub(r'\1', arg)
949            self.entry.parameterlist.append(arg)
950            if arg not in self.entry.parameterdescs:
951                self.entry.parameterdescs[arg] = self.undescribed
952                self.emit_msg(ln,
953                              f"Enum value '{arg}' not described in enum '{declaration_name}'")
954            member_set.add(arg)
955        #
956        # Ensure that every described member actually exists in the enum.
957        #
958        for k in self.entry.parameterdescs:
959            if k not in member_set:
960                self.emit_msg(ln,
961                              f"Excess enum value '@{k}' description in '{declaration_name}'")
962
963        self.output_declaration('enum', declaration_name,
964                                purpose=self.entry.declaration_purpose)
965
966    def dump_var(self, ln, proto):
967        """
968        Store variables that are part of kAPI.
969        """
970        VAR_ATTRIBS = [
971            "extern",
972        ]
973        OPTIONAL_VAR_ATTR = "^(?:" + "|".join(VAR_ATTRIBS) + ")?"
974
975        sub_prefixes = [
976            (KernRe(r"__read_mostly"), ""),
977            (KernRe(r"__ro_after_init"), ""),
978            (KernRe(r"(?://.*)$"), ""),
979            (KernRe(r"(?:/\*.*\*/)"), ""),
980            (KernRe(r";$"), ""),
981            (KernRe(r"=.*"), ""),
982        ]
983
984        #
985        # Store the full prototype before modifying it
986        #
987        full_proto = proto
988        declaration_name = None
989
990        #
991        # Handle macro definitions
992        #
993        macro_prefixes = [
994            KernRe(r"DEFINE_[\w_]+\s*\(([\w_]+)\)"),
995        ]
996
997        for r in macro_prefixes:
998            match = r.search(proto)
999            if match:
1000                declaration_name = match.group(1)
1001                break
1002
1003        #
1004        # Drop comments and macros to have a pure C prototype
1005        #
1006        if not declaration_name:
1007            for r, sub in sub_prefixes:
1008                proto = r.sub(sub, proto)
1009
1010        proto = proto.rstrip()
1011
1012        #
1013        # Variable name is at the end of the declaration
1014        #
1015
1016        default_val = None
1017
1018        r= KernRe(OPTIONAL_VAR_ATTR + r"\w.*\s+(?:\*+)?([\w_]+)\s*[\d\]\[]*\s*(=.*)?")
1019        if r.match(proto):
1020            if not declaration_name:
1021                declaration_name = r.group(1)
1022
1023            default_val = r.group(2)
1024        else:
1025            r= KernRe(OPTIONAL_VAR_ATTR + r"(?:\w.*)?\s+(?:\*+)?(?:[\w_]+)\s*[\d\]\[]*\s*(=.*)?")
1026        if r.match(proto):
1027            default_val = r.group(1)
1028
1029        if not declaration_name:
1030           self.emit_msg(ln,f"{proto}: can't parse variable")
1031           return
1032
1033        if default_val:
1034            default_val = default_val.lstrip("=").strip()
1035
1036        self.output_declaration("var", declaration_name,
1037                                full_proto=full_proto,
1038                                default_val=default_val,
1039                                purpose=self.entry.declaration_purpose)
1040
1041    def dump_declaration(self, ln, prototype):
1042        """
1043        Store a data declaration inside self.entries array.
1044        """
1045
1046        if self.entry.decl_type == "enum":
1047            self.dump_enum(ln, prototype)
1048        elif self.entry.decl_type == "typedef":
1049            self.dump_typedef(ln, prototype)
1050        elif self.entry.decl_type in ["union", "struct"]:
1051            self.dump_struct(ln, prototype)
1052        elif self.entry.decl_type == "var":
1053            self.dump_var(ln, prototype)
1054        else:
1055            # This would be a bug
1056            self.emit_message(ln, f'Unknown declaration type: {self.entry.decl_type}')
1057
1058    def dump_function(self, ln, prototype):
1059        """
1060        Store a function or function macro inside self.entries array.
1061        """
1062
1063        found = func_macro = False
1064        return_type = ''
1065        decl_type = 'function'
1066        #
1067        # Apply the initial transformations.
1068        #
1069        prototype = apply_transforms(function_xforms, prototype)
1070        #
1071        # If we have a macro, remove the "#define" at the front.
1072        #
1073        new_proto = KernRe(r"^#\s*define\s+").sub("", prototype)
1074        if new_proto != prototype:
1075            prototype = new_proto
1076            #
1077            # Dispense with the simple "#define A B" case here; the key
1078            # is the space after the name of the symbol being defined.
1079            # NOTE that the seemingly misnamed "func_macro" indicates a
1080            # macro *without* arguments.
1081            #
1082            r = KernRe(r'^(\w+)\s+')
1083            if r.search(prototype):
1084                return_type = ''
1085                declaration_name = r.group(1)
1086                func_macro = True
1087                found = True
1088
1089        # Yes, this truly is vile.  We are looking for:
1090        # 1. Return type (may be nothing if we're looking at a macro)
1091        # 2. Function name
1092        # 3. Function parameters.
1093        #
1094        # All the while we have to watch out for function pointer parameters
1095        # (which IIRC is what the two sections are for), C types (these
1096        # regexps don't even start to express all the possibilities), and
1097        # so on.
1098        #
1099        # If you mess with these regexps, it's a good idea to check that
1100        # the following functions' documentation still comes out right:
1101        # - parport_register_device (function pointer parameters)
1102        # - atomic_set (macro)
1103        # - pci_match_device, __copy_to_user (long return type)
1104
1105        name = r'\w+'
1106        type1 = r'(?:[\w\s]+)?'
1107        type2 = r'(?:[\w\s]+\*+)+'
1108        #
1109        # Attempt to match first on (args) with no internal parentheses; this
1110        # lets us easily filter out __acquires() and other post-args stuff.  If
1111        # that fails, just grab the rest of the line to the last closing
1112        # parenthesis.
1113        #
1114        proto_args = r'\(([^\(]*|.*)\)'
1115        #
1116        # (Except for the simple macro case) attempt to split up the prototype
1117        # in the various ways we understand.
1118        #
1119        if not found:
1120            patterns = [
1121                rf'^()({name})\s*{proto_args}',
1122                rf'^({type1})\s+({name})\s*{proto_args}',
1123                rf'^({type2})\s*({name})\s*{proto_args}',
1124            ]
1125
1126            for p in patterns:
1127                r = KernRe(p)
1128                if r.match(prototype):
1129                    return_type = r.group(1)
1130                    declaration_name = r.group(2)
1131                    args = r.group(3)
1132                    self.create_parameter_list(ln, decl_type, args, ',',
1133                                               declaration_name)
1134                    found = True
1135                    break
1136        #
1137        # Parsing done; make sure that things are as we expect.
1138        #
1139        if not found:
1140            self.emit_msg(ln,
1141                          f"cannot understand function prototype: '{prototype}'")
1142            return
1143        if self.entry.identifier != declaration_name:
1144            self.emit_msg(ln, f"expecting prototype for {self.entry.identifier}(). "
1145                          f"Prototype was for {declaration_name}() instead")
1146            return
1147        self.check_sections(ln, declaration_name, "function")
1148        self.check_return_section(ln, declaration_name, return_type)
1149        #
1150        # Store the result.
1151        #
1152        self.output_declaration(decl_type, declaration_name,
1153                                typedef=('typedef' in return_type),
1154                                functiontype=return_type,
1155                                purpose=self.entry.declaration_purpose,
1156                                func_macro=func_macro)
1157
1158
1159    def dump_typedef(self, ln, proto):
1160        """
1161        Store a ``typedef`` inside self.entries array.
1162        """
1163        #
1164        # We start by looking for function typedefs.
1165        #
1166        typedef_type = r'typedef((?:\s+[\w*]+\b){0,7}\s+(?:\w+\b|\*+))\s*'
1167        typedef_ident = r'\*?\s*(\w\S+)\s*'
1168        typedef_args = r'\s*\((.*)\);'
1169
1170        typedef1 = KernRe(typedef_type + r'\(' + typedef_ident + r'\)' + typedef_args)
1171        typedef2 = KernRe(typedef_type + typedef_ident + typedef_args)
1172
1173        # Parse function typedef prototypes
1174        for r in [typedef1, typedef2]:
1175            if not r.match(proto):
1176                continue
1177
1178            return_type = r.group(1).strip()
1179            declaration_name = r.group(2)
1180            args = r.group(3)
1181
1182            if self.entry.identifier != declaration_name:
1183                self.emit_msg(ln,
1184                              f"expecting prototype for typedef {self.entry.identifier}. Prototype was for typedef {declaration_name} instead\n")
1185                return
1186
1187            self.create_parameter_list(ln, 'function', args, ',', declaration_name)
1188
1189            self.output_declaration('function', declaration_name,
1190                                    typedef=True,
1191                                    functiontype=return_type,
1192                                    purpose=self.entry.declaration_purpose)
1193            return
1194        #
1195        # Not a function, try to parse a simple typedef.
1196        #
1197        r = KernRe(r'typedef.*\s+(\w+)\s*;')
1198        if r.match(proto):
1199            declaration_name = r.group(1)
1200
1201            if self.entry.identifier != declaration_name:
1202                self.emit_msg(ln,
1203                              f"expecting prototype for typedef {self.entry.identifier}. Prototype was for typedef {declaration_name} instead\n")
1204                return
1205
1206            self.output_declaration('typedef', declaration_name,
1207                                    purpose=self.entry.declaration_purpose)
1208            return
1209
1210        self.emit_msg(ln, "error: Cannot parse typedef!")
1211
1212    @staticmethod
1213    def process_export(function_set, line):
1214        """
1215        process ``EXPORT_SYMBOL*`` tags
1216
1217        This method doesn't use any variable from the class, so declare it
1218        with a staticmethod decorator.
1219        """
1220
1221        # We support documenting some exported symbols with different
1222        # names.  A horrible hack.
1223        suffixes = [ '_noprof' ]
1224
1225        # Note: it accepts only one EXPORT_SYMBOL* per line, as having
1226        # multiple export lines would violate Kernel coding style.
1227
1228        if export_symbol.search(line):
1229            symbol = export_symbol.group(2)
1230        elif export_symbol_ns.search(line):
1231            symbol = export_symbol_ns.group(2)
1232        else:
1233            return False
1234        #
1235        # Found an export, trim out any special suffixes
1236        #
1237        for suffix in suffixes:
1238            # Be backward compatible with Python < 3.9
1239            if symbol.endswith(suffix):
1240                symbol = symbol[:-len(suffix)]
1241        function_set.add(symbol)
1242        return True
1243
1244    def process_normal(self, ln, line):
1245        """
1246        STATE_NORMAL: looking for the ``/**`` to begin everything.
1247        """
1248
1249        if not doc_start.match(line):
1250            return
1251
1252        # start a new entry
1253        self.reset_state(ln)
1254
1255        # next line is always the function name
1256        self.state = state.NAME
1257
1258    def process_name(self, ln, line):
1259        """
1260        STATE_NAME: Looking for the "name - description" line
1261        """
1262        #
1263        # Check for a DOC: block and handle them specially.
1264        #
1265        if doc_block.search(line):
1266
1267            if not doc_block.group(1):
1268                self.entry.begin_section(ln, "Introduction")
1269            else:
1270                self.entry.begin_section(ln, doc_block.group(1))
1271
1272            self.entry.identifier = self.entry.section
1273            self.state = state.DOCBLOCK
1274        #
1275        # Otherwise we're looking for a normal kerneldoc declaration line.
1276        #
1277        elif doc_decl.search(line):
1278            self.entry.identifier = doc_decl.group(1)
1279
1280            # Test for data declaration
1281            if doc_begin_data.search(line):
1282                self.entry.decl_type = doc_begin_data.group(1)
1283                self.entry.identifier = doc_begin_data.group(2)
1284            #
1285            # Look for a function description
1286            #
1287            elif doc_begin_func.search(line):
1288                self.entry.identifier = doc_begin_func.group(1)
1289                self.entry.decl_type = "function"
1290            #
1291            # We struck out.
1292            #
1293            else:
1294                self.emit_msg(ln,
1295                              f"This comment starts with '/**', but isn't a kernel-doc comment. Refer to Documentation/doc-guide/kernel-doc.rst\n{line}")
1296                self.state = state.NORMAL
1297                return
1298            #
1299            # OK, set up for a new kerneldoc entry.
1300            #
1301            self.state = state.BODY
1302            self.entry.identifier = self.entry.identifier.strip(" ")
1303            # if there's no @param blocks need to set up default section here
1304            self.entry.begin_section(ln + 1)
1305            #
1306            # Find the description portion, which *should* be there but
1307            # isn't always.
1308            # (We should be able to capture this from the previous parsing - someday)
1309            #
1310            r = KernRe("[-:](.*)")
1311            if r.search(line):
1312                self.entry.declaration_purpose = trim_whitespace(r.group(1))
1313                self.state = state.DECLARATION
1314            else:
1315                self.entry.declaration_purpose = ""
1316
1317            if not self.entry.declaration_purpose and self.config.wshort_desc:
1318                self.emit_msg(ln,
1319                              f"missing initial short description on line:\n{line}")
1320
1321            if not self.entry.identifier and self.entry.decl_type != "enum":
1322                self.emit_msg(ln,
1323                              f"wrong kernel-doc identifier on line:\n{line}")
1324                self.state = state.NORMAL
1325
1326            if self.config.verbose:
1327                self.emit_msg(ln,
1328                              f"Scanning doc for {self.entry.decl_type} {self.entry.identifier}",
1329                                  warning=False)
1330        #
1331        # Failed to find an identifier. Emit a warning
1332        #
1333        else:
1334            self.emit_msg(ln, f"Cannot find identifier on line:\n{line}")
1335
1336    def is_new_section(self, ln, line):
1337        """
1338        Helper function to determine if a new section is being started.
1339        """
1340        if doc_sect.search(line):
1341            self.state = state.BODY
1342            #
1343            # Pick out the name of our new section, tweaking it if need be.
1344            #
1345            newsection = doc_sect.group(1)
1346            if newsection.lower() == 'description':
1347                newsection = 'Description'
1348            elif newsection.lower() == 'context':
1349                newsection = 'Context'
1350                self.state = state.SPECIAL_SECTION
1351            elif newsection.lower() in ["@return", "@returns",
1352                                        "return", "returns"]:
1353                newsection = "Return"
1354                self.state = state.SPECIAL_SECTION
1355            elif newsection[0] == '@':
1356                self.state = state.SPECIAL_SECTION
1357            #
1358            # Initialize the contents, and get the new section going.
1359            #
1360            newcontents = doc_sect.group(2)
1361            if not newcontents:
1362                newcontents = ""
1363            self.dump_section()
1364            self.entry.begin_section(ln, newsection)
1365            self.entry.leading_space = None
1366
1367            self.entry.add_text(newcontents.lstrip())
1368            return True
1369        return False
1370
1371    def is_comment_end(self, ln, line):
1372        """
1373        Helper function to detect (and effect) the end of a kerneldoc comment.
1374        """
1375        if doc_end.search(line):
1376            self.dump_section()
1377
1378            # Look for doc_com + <text> + doc_end:
1379            r = KernRe(r'\s*\*\s*[a-zA-Z_0-9:.]+\*/')
1380            if r.match(line):
1381                self.emit_msg(ln, f"suspicious ending line: {line}")
1382
1383            self.entry.prototype = ""
1384            self.entry.new_start_line = ln + 1
1385
1386            self.state = state.PROTO
1387            return True
1388        return False
1389
1390
1391    def process_decl(self, ln, line):
1392        """
1393        STATE_DECLARATION: We've seen the beginning of a declaration.
1394        """
1395        if self.is_new_section(ln, line) or self.is_comment_end(ln, line):
1396            return
1397        #
1398        # Look for anything with the " * " line beginning.
1399        #
1400        if doc_content.search(line):
1401            cont = doc_content.group(1)
1402            #
1403            # A blank line means that we have moved out of the declaration
1404            # part of the comment (without any "special section" parameter
1405            # descriptions).
1406            #
1407            if cont == "":
1408                self.state = state.BODY
1409            #
1410            # Otherwise we have more of the declaration section to soak up.
1411            #
1412            else:
1413                self.entry.declaration_purpose = \
1414                    trim_whitespace(self.entry.declaration_purpose + ' ' + cont)
1415        else:
1416            # Unknown line, ignore
1417            self.emit_msg(ln, f"bad line: {line}")
1418
1419
1420    def process_special(self, ln, line):
1421        """
1422        STATE_SPECIAL_SECTION: a section ending with a blank line.
1423        """
1424        #
1425        # If we have hit a blank line (only the " * " marker), then this
1426        # section is done.
1427        #
1428        if KernRe(r"\s*\*\s*$").match(line):
1429            self.entry.begin_section(ln, dump = True)
1430            self.state = state.BODY
1431            return
1432        #
1433        # Not a blank line, look for the other ways to end the section.
1434        #
1435        if self.is_new_section(ln, line) or self.is_comment_end(ln, line):
1436            return
1437        #
1438        # OK, we should have a continuation of the text for this section.
1439        #
1440        if doc_content.search(line):
1441            cont = doc_content.group(1)
1442            #
1443            # If the lines of text after the first in a special section have
1444            # leading white space, we need to trim it out or Sphinx will get
1445            # confused.  For the second line (the None case), see what we
1446            # find there and remember it.
1447            #
1448            if self.entry.leading_space is None:
1449                r = KernRe(r'^(\s+)')
1450                if r.match(cont):
1451                    self.entry.leading_space = len(r.group(1))
1452                else:
1453                    self.entry.leading_space = 0
1454            #
1455            # Otherwise, before trimming any leading chars, be *sure*
1456            # that they are white space.  We should maybe warn if this
1457            # isn't the case.
1458            #
1459            for i in range(0, self.entry.leading_space):
1460                if cont[i] != " ":
1461                    self.entry.leading_space = i
1462                    break
1463            #
1464            # Add the trimmed result to the section and we're done.
1465            #
1466            self.entry.add_text(cont[self.entry.leading_space:])
1467        else:
1468            # Unknown line, ignore
1469            self.emit_msg(ln, f"bad line: {line}")
1470
1471    def process_body(self, ln, line):
1472        """
1473        STATE_BODY: the bulk of a kerneldoc comment.
1474        """
1475        if self.is_new_section(ln, line) or self.is_comment_end(ln, line):
1476            return
1477
1478        if doc_content.search(line):
1479            cont = doc_content.group(1)
1480            self.entry.add_text(cont)
1481        else:
1482            # Unknown line, ignore
1483            self.emit_msg(ln, f"bad line: {line}")
1484
1485    def process_inline_name(self, ln, line):
1486        """STATE_INLINE_NAME: beginning of docbook comments within a prototype."""
1487
1488        if doc_inline_sect.search(line):
1489            self.entry.begin_section(ln, doc_inline_sect.group(1))
1490            self.entry.add_text(doc_inline_sect.group(2).lstrip())
1491            self.state = state.INLINE_TEXT
1492        elif doc_inline_end.search(line):
1493            self.dump_section()
1494            self.state = state.PROTO
1495        elif doc_content.search(line):
1496            self.emit_msg(ln, f"Incorrect use of kernel-doc format: {line}")
1497            self.state = state.PROTO
1498        # else ... ??
1499
1500    def process_inline_text(self, ln, line):
1501        """STATE_INLINE_TEXT: docbook comments within a prototype."""
1502
1503        if doc_inline_end.search(line):
1504            self.dump_section()
1505            self.state = state.PROTO
1506        elif doc_content.search(line):
1507            self.entry.add_text(doc_content.group(1))
1508        # else ... ??
1509
1510    def syscall_munge(self, ln, proto):         # pylint: disable=W0613
1511        """
1512        Handle syscall definitions.
1513        """
1514
1515        is_void = False
1516
1517        # Strip newlines/CR's
1518        proto = re.sub(r'[\r\n]+', ' ', proto)
1519
1520        # Check if it's a SYSCALL_DEFINE0
1521        if 'SYSCALL_DEFINE0' in proto:
1522            is_void = True
1523
1524        # Replace SYSCALL_DEFINE with correct return type & function name
1525        proto = KernRe(r'SYSCALL_DEFINE.*\(').sub('long sys_', proto)
1526
1527        r = KernRe(r'long\s+(sys_.*?),')
1528        if r.search(proto):
1529            proto = KernRe(',').sub('(', proto, count=1)
1530        elif is_void:
1531            proto = KernRe(r'\)').sub('(void)', proto, count=1)
1532
1533        # Now delete all of the odd-numbered commas in the proto
1534        # so that argument types & names don't have a comma between them
1535        count = 0
1536        length = len(proto)
1537
1538        if is_void:
1539            length = 0  # skip the loop if is_void
1540
1541        for ix in range(length):
1542            if proto[ix] == ',':
1543                count += 1
1544                if count % 2 == 1:
1545                    proto = proto[:ix] + ' ' + proto[ix + 1:]
1546
1547        return proto
1548
1549    def tracepoint_munge(self, ln, proto):
1550        """
1551        Handle tracepoint definitions.
1552        """
1553
1554        tracepointname = None
1555        tracepointargs = None
1556
1557        # Match tracepoint name based on different patterns
1558        r = KernRe(r'TRACE_EVENT\((.*?),')
1559        if r.search(proto):
1560            tracepointname = r.group(1)
1561
1562        r = KernRe(r'DEFINE_SINGLE_EVENT\((.*?),')
1563        if r.search(proto):
1564            tracepointname = r.group(1)
1565
1566        r = KernRe(r'DEFINE_EVENT\((.*?),(.*?),')
1567        if r.search(proto):
1568            tracepointname = r.group(2)
1569
1570        if tracepointname:
1571            tracepointname = tracepointname.lstrip()
1572
1573        r = KernRe(r'TP_PROTO\((.*?)\)')
1574        if r.search(proto):
1575            tracepointargs = r.group(1)
1576
1577        if not tracepointname or not tracepointargs:
1578            self.emit_msg(ln,
1579                          f"Unrecognized tracepoint format:\n{proto}\n")
1580        else:
1581            proto = f"static inline void trace_{tracepointname}({tracepointargs})"
1582            self.entry.identifier = f"trace_{self.entry.identifier}"
1583
1584        return proto
1585
1586    def process_proto_function(self, ln, line):
1587        """Ancillary routine to process a function prototype."""
1588
1589        # strip C99-style comments to end of line
1590        line = KernRe(r"//.*$", re.S).sub('', line)
1591        #
1592        # Soak up the line's worth of prototype text, stopping at { or ; if present.
1593        #
1594        if KernRe(r'\s*#\s*define').match(line):
1595            self.entry.prototype = line
1596        elif not line.startswith('#'):   # skip other preprocessor stuff
1597            r = KernRe(r'([^\{]*)')
1598            if r.match(line):
1599                self.entry.prototype += r.group(1) + " "
1600        #
1601        # If we now have the whole prototype, clean it up and declare victory.
1602        #
1603        if '{' in line or ';' in line or KernRe(r'\s*#\s*define').match(line):
1604            # strip comments and surrounding spaces
1605            self.entry.prototype = KernRe(r'/\*.*\*/').sub('', self.entry.prototype).strip()
1606            #
1607            # Handle self.entry.prototypes for function pointers like:
1608            #       int (*pcs_config)(struct foo)
1609            # by turning it into
1610            #	    int pcs_config(struct foo)
1611            #
1612            r = KernRe(r'^(\S+\s+)\(\s*\*(\S+)\)')
1613            self.entry.prototype = r.sub(r'\1\2', self.entry.prototype)
1614            #
1615            # Handle special declaration syntaxes
1616            #
1617            if 'SYSCALL_DEFINE' in self.entry.prototype:
1618                self.entry.prototype = self.syscall_munge(ln,
1619                                                          self.entry.prototype)
1620            else:
1621                r = KernRe(r'TRACE_EVENT|DEFINE_EVENT|DEFINE_SINGLE_EVENT')
1622                if r.search(self.entry.prototype):
1623                    self.entry.prototype = self.tracepoint_munge(ln,
1624                                                                 self.entry.prototype)
1625            #
1626            # ... and we're done
1627            #
1628            self.dump_function(ln, self.entry.prototype)
1629            self.reset_state(ln)
1630
1631    def process_proto_type(self, ln, line):
1632        """
1633        Ancillary routine to process a type.
1634        """
1635
1636        # Strip C99-style comments and surrounding whitespace
1637        line = KernRe(r"//.*$", re.S).sub('', line).strip()
1638        if not line:
1639            return # nothing to see here
1640
1641        # To distinguish preprocessor directive from regular declaration later.
1642        if line.startswith('#'):
1643            line += ";"
1644        #
1645        # Split the declaration on any of { } or ;, and accumulate pieces
1646        # until we hit a semicolon while not inside {brackets}
1647        #
1648        r = KernRe(r'(.*?)([{};])')
1649        for chunk in r.split(line):
1650            if chunk:  # Ignore empty matches
1651                self.entry.prototype += chunk
1652                #
1653                # This cries out for a match statement ... someday after we can
1654                # drop Python 3.9 ...
1655                #
1656                if chunk == '{':
1657                    self.entry.brcount += 1
1658                elif chunk == '}':
1659                    self.entry.brcount -= 1
1660                elif chunk == ';' and self.entry.brcount <= 0:
1661                    self.dump_declaration(ln, self.entry.prototype)
1662                    self.reset_state(ln)
1663                    return
1664        #
1665        # We hit the end of the line while still in the declaration; put
1666        # in a space to represent the newline.
1667        #
1668        self.entry.prototype += ' '
1669
1670    def process_proto(self, ln, line):
1671        """STATE_PROTO: reading a function/whatever prototype."""
1672
1673        if doc_inline_oneline.search(line):
1674            self.entry.begin_section(ln, doc_inline_oneline.group(1))
1675            self.entry.add_text(doc_inline_oneline.group(2))
1676            self.dump_section()
1677
1678        elif doc_inline_start.search(line):
1679            self.state = state.INLINE_NAME
1680
1681        elif self.entry.decl_type == 'function':
1682            self.process_proto_function(ln, line)
1683
1684        else:
1685            self.process_proto_type(ln, line)
1686
1687    def process_docblock(self, ln, line):
1688        """STATE_DOCBLOCK: within a ``DOC:`` block."""
1689
1690        if doc_end.search(line):
1691            self.dump_section()
1692            self.output_declaration("doc", self.entry.identifier)
1693            self.reset_state(ln)
1694
1695        elif doc_content.search(line):
1696            self.entry.add_text(doc_content.group(1))
1697
1698    def parse_export(self):
1699        """
1700        Parses ``EXPORT_SYMBOL*`` macros from a single Kernel source file.
1701        """
1702
1703        export_table = set()
1704
1705        try:
1706            with open(self.fname, "r", encoding="utf8",
1707                      errors="backslashreplace") as fp:
1708
1709                for line in fp:
1710                    self.process_export(export_table, line)
1711
1712        except IOError:
1713            return None
1714
1715        return export_table
1716
1717    #: The state/action table telling us which function to invoke in each state.
1718    state_actions = {
1719        state.NORMAL:			process_normal,
1720        state.NAME:			process_name,
1721        state.BODY:			process_body,
1722        state.DECLARATION:		process_decl,
1723        state.SPECIAL_SECTION:		process_special,
1724        state.INLINE_NAME:		process_inline_name,
1725        state.INLINE_TEXT:		process_inline_text,
1726        state.PROTO:			process_proto,
1727        state.DOCBLOCK:			process_docblock,
1728        }
1729
1730    def parse_kdoc(self):
1731        """
1732        Open and process each line of a C source file.
1733        The parsing is controlled via a state machine, and the line is passed
1734        to a different process function depending on the state. The process
1735        function may update the state as needed.
1736
1737        Besides parsing kernel-doc tags, it also parses export symbols.
1738        """
1739
1740        prev = ""
1741        prev_ln = None
1742        export_table = set()
1743
1744        try:
1745            with open(self.fname, "r", encoding="utf8",
1746                      errors="backslashreplace") as fp:
1747                for ln, line in enumerate(fp):
1748
1749                    line = line.expandtabs().strip("\n")
1750
1751                    # Group continuation lines on prototypes
1752                    if self.state == state.PROTO:
1753                        if line.endswith("\\"):
1754                            prev += line.rstrip("\\")
1755                            if not prev_ln:
1756                                prev_ln = ln
1757                            continue
1758
1759                        if prev:
1760                            ln = prev_ln
1761                            line = prev + line
1762                            prev = ""
1763                            prev_ln = None
1764
1765                    self.config.log.debug("%d %s: %s",
1766                                          ln, state.name[self.state],
1767                                          line)
1768
1769                    # This is an optimization over the original script.
1770                    # There, when export_file was used for the same file,
1771                    # it was read twice. Here, we use the already-existing
1772                    # loop to parse exported symbols as well.
1773                    #
1774                    if (self.state != state.NORMAL) or \
1775                       not self.process_export(export_table, line):
1776                        # Hand this line to the appropriate state handler
1777                        self.state_actions[self.state](self, ln, line)
1778
1779            self.emit_unused_warnings()
1780
1781        except OSError:
1782            self.config.log.error(f"Error: Cannot open file {self.fname}")
1783
1784        return export_table, self.entries
1785