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Diffstat (limited to 'scripts/check-obsolete-constructs.py')
| -rwxr-xr-x | scripts/check-obsolete-constructs.py | 466 |
1 files changed, 466 insertions, 0 deletions
diff --git a/scripts/check-obsolete-constructs.py b/scripts/check-obsolete-constructs.py new file mode 100755 index 0000000000..ce5c72251f --- /dev/null +++ b/scripts/check-obsolete-constructs.py @@ -0,0 +1,466 @@ +#! /usr/bin/python3 +# Copyright (C) 2019 Free Software Foundation, Inc. +# This file is part of the GNU C Library. +# +# The GNU C Library is free software; you can redistribute it and/or +# modify it under the terms of the GNU Lesser General Public +# License as published by the Free Software Foundation; either +# version 2.1 of the License, or (at your option) any later version. +# +# The GNU C Library is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +# Lesser General Public License for more details. +# +# You should have received a copy of the GNU Lesser General Public +# License along with the GNU C Library; if not, see +# <http://www.gnu.org/licenses/>. + +"""Verifies that installed headers do not use any obsolete constructs: + * legacy BSD typedefs superseded by <stdint.h>: + ushort uint ulong u_char u_short u_int u_long u_intNN_t quad_t u_quad_t + (sys/types.h is allowed to _define_ these types, but not to use them + to define anything else). +""" + +import argparse +import collections +import re +import sys + +# Simplified lexical analyzer for C preprocessing tokens. +# Does not implement trigraphs. +# Does not implement backslash-newline in the middle of any lexical +# item other than a string literal. +# Does not implement universal-character-names in identifiers. +# Treats prefixed strings (e.g. L"...") as two tokens (L and "...") +# Accepts non-ASCII characters only within comments and strings. + +# Caution: The order of the outermost alternation matters. +# STRING must be before BAD_STRING, CHARCONST before BAD_CHARCONST, +# BLOCK_COMMENT before BAD_BLOCK_COM before PUNCTUATOR, and OTHER must +# be last. +# Caution: There should be no capturing groups other than the named +# captures in the outermost alternation. + +# For reference, these are all of the C punctuators as of C11: +# [ ] ( ) { } , ; ? ~ +# ! != * *= / /= ^ ^= = == +# # ## +# % %= %> %: %:%: +# & &= && +# | |= || +# + += ++ +# - -= -- -> +# . ... +# : :> +# < <% <: << <<= <= +# > >= >> >>= + +# The BAD_* tokens are not part of the official definition of pp-tokens; +# they match unclosed strings, character constants, and block comments, +# so that the regex engine doesn't have to backtrack all the way to the +# beginning of a broken construct and then emit dozens of junk tokens. + +PP_TOKEN_RE_ = re.compile(r""" + (?P<STRING> \"(?:[^\"\\\r\n]|\\(?:[\r\n -~]|\r\n))*\") + |(?P<BAD_STRING> \"(?:[^\"\\\r\n]|\\[ -~])*) + |(?P<CHARCONST> \'(?:[^\'\\\r\n]|\\(?:[\r\n -~]|\r\n))*\') + |(?P<BAD_CHARCONST> \'(?:[^\'\\\r\n]|\\[ -~])*) + |(?P<BLOCK_COMMENT> /\*(?:\*(?!/)|[^*])*\*/) + |(?P<BAD_BLOCK_COM> /\*(?:\*(?!/)|[^*])*\*?) + |(?P<LINE_COMMENT> //[^\r\n]*) + |(?P<IDENT> [_a-zA-Z][_a-zA-Z0-9]*) + |(?P<PP_NUMBER> \.?[0-9](?:[0-9a-df-oq-zA-DF-OQ-Z_.]|[eEpP][+-]?)*) + |(?P<PUNCTUATOR> + [,;?~(){}\[\]] + | [!*/^=]=? + | \#\#? + | %(?:[=>]|:(?:%:)?)? + | &[=&]? + |\|[=|]? + |\+[=+]? + | -[=->]? + |\.(?:\.\.)? + | :>? + | <(?:[%:]|<(?:=|<=?)?)? + | >(?:=|>=?)?) + |(?P<ESCNL> \\(?:\r|\n|\r\n)) + |(?P<WHITESPACE> [ \t\n\r\v\f]+) + |(?P<OTHER> .) +""", re.DOTALL | re.VERBOSE) + +HEADER_NAME_RE_ = re.compile(r""" + < [^>\r\n]+ > + | " [^"\r\n]+ " +""", re.DOTALL | re.VERBOSE) + +ENDLINE_RE_ = re.compile(r"""\r|\n|\r\n""") + +# based on the sample code in the Python re documentation +Token_ = collections.namedtuple("Token", ( + "kind", "text", "line", "column", "context")) +Token_.__doc__ = """ + One C preprocessing token, comment, or chunk of whitespace. + 'kind' identifies the token type, which will be one of: + STRING, CHARCONST, BLOCK_COMMENT, LINE_COMMENT, IDENT, + PP_NUMBER, PUNCTUATOR, ESCNL, WHITESPACE, HEADER_NAME, + or OTHER. The BAD_* alternatives in PP_TOKEN_RE_ are + handled within tokenize_c, below. + + 'text' is the sequence of source characters making up the token; + no decoding whatsoever is performed. + + 'line' and 'column' give the position of the first character of the + token within the source file. They are both 1-based. + + 'context' indicates whether or not this token occurred within a + preprocessing directive; it will be None for running text, + '<null>' for the leading '#' of a directive line (because '#' + all by itself on a line is a "null directive"), or the name of + the directive for tokens within a directive line, starting with + the IDENT for the name itself. +""" + +def tokenize_c(file_contents, reporter): + """Yield a series of Token objects, one for each preprocessing + token, comment, or chunk of whitespace within FILE_CONTENTS. + The REPORTER object is expected to have one method, + reporter.error(token, message), which will be called to + indicate a lexical error at the position of TOKEN. + If MESSAGE contains the four-character sequence '{!r}', that + is expected to be replaced by repr(token.text). + """ + + Token = Token_ + PP_TOKEN_RE = PP_TOKEN_RE_ + ENDLINE_RE = ENDLINE_RE_ + HEADER_NAME_RE = HEADER_NAME_RE_ + + line_num = 1 + line_start = 0 + pos = 0 + limit = len(file_contents) + directive = None + at_bol = True + while pos < limit: + if directive == "include": + mo = HEADER_NAME_RE.match(file_contents, pos) + if mo: + kind = "HEADER_NAME" + directive = "after_include" + else: + mo = PP_TOKEN_RE.match(file_contents, pos) + kind = mo.lastgroup + if kind != "WHITESPACE": + directive = "after_include" + else: + mo = PP_TOKEN_RE.match(file_contents, pos) + kind = mo.lastgroup + + text = mo.group() + line = line_num + column = mo.start() - line_start + adj_line_start = 0 + # only these kinds can contain a newline + if kind in ("WHITESPACE", "BLOCK_COMMENT", "LINE_COMMENT", + "STRING", "CHARCONST", "BAD_BLOCK_COM", "ESCNL"): + for tmo in ENDLINE_RE.finditer(text): + line_num += 1 + adj_line_start = tmo.end() + if adj_line_start: + line_start = mo.start() + adj_line_start + + # Track whether or not we are scanning a preprocessing directive. + if kind == "LINE_COMMENT" or (kind == "WHITESPACE" and adj_line_start): + at_bol = True + directive = None + else: + if kind == "PUNCTUATOR" and text == "#" and at_bol: + directive = "<null>" + elif kind == "IDENT" and directive == "<null>": + directive = text + at_bol = False + + # Report ill-formed tokens and rewrite them as their well-formed + # equivalents, so downstream processing doesn't have to know about them. + # (Rewriting instead of discarding provides better error recovery.) + if kind == "BAD_BLOCK_COM": + reporter.error(Token("BAD_BLOCK_COM", "", line, column+1, ""), + "unclosed block comment") + text += "*/" + kind = "BLOCK_COMMENT" + elif kind == "BAD_STRING": + reporter.error(Token("BAD_STRING", "", line, column+1, ""), + "unclosed string") + text += "\"" + kind = "STRING" + elif kind == "BAD_CHARCONST": + reporter.error(Token("BAD_CHARCONST", "", line, column+1, ""), + "unclosed char constant") + text += "'" + kind = "CHARCONST" + + tok = Token(kind, text, line, column+1, + "include" if directive == "after_include" else directive) + # Do not complain about OTHER tokens inside macro definitions. + # $ and @ appear in macros defined by headers intended to be + # included from assembly language, e.g. sysdeps/mips/sys/asm.h. + if kind == "OTHER" and directive != "define": + self.error(tok, "stray {!r} in program") + + yield tok + pos = mo.end() + +# +# Base and generic classes for individual checks. +# + +class ConstructChecker: + """Scan a stream of C preprocessing tokens and possibly report + problems with them. The REPORTER object passed to __init__ has + one method, reporter.error(token, message), which should be + called to indicate a problem detected at the position of TOKEN. + If MESSAGE contains the four-character sequence '{!r}' then that + will be replaced with a textual representation of TOKEN. + """ + def __init__(self, reporter): + self.reporter = reporter + + def examine(self, tok): + """Called once for each token in a header file. + Call self.reporter.error if a problem is detected. + """ + raise NotImplementedError + + def eof(self): + """Called once at the end of the stream. Subclasses need only + override this if it might have something to do.""" + pass + +class NoCheck(ConstructChecker): + """Generic checker class which doesn't do anything. Substitute this + class for a real checker when a particular check should be skipped + for some file.""" + + def examine(self, tok): + pass + +# +# Check for obsolete type names. +# + +# The obsolete type names we're looking for: +OBSOLETE_TYPE_RE_ = re.compile(r"""\A + (__)? + ( quad_t + | u(?: short | int | long + | _(?: char | short | int(?:[0-9]+_t)? | long | quad_t ))) +\Z""", re.VERBOSE) + +class ObsoleteNotAllowed(ConstructChecker): + """Don't allow any use of the obsolete typedefs.""" + def examine(self, tok): + if OBSOLETE_TYPE_RE_.match(tok.text): + self.reporter.error(tok, "use of {!r}") + +class ObsoletePrivateDefinitionsAllowed(ConstructChecker): + """Allow definitions of the private versions of the + obsolete typedefs; that is, 'typedef [anything] __obsolete;' + """ + def __init__(self, reporter): + super().__init__(reporter) + self.in_typedef = False + self.prev_token = None + + def examine(self, tok): + # bits/types.h hides 'typedef' in a macro sometimes. + if (tok.kind == "IDENT" + and tok.text in ("typedef", "__STD_TYPE") + and tok.context is None): + self.in_typedef = True + elif tok.kind == "PUNCTUATOR" and tok.text == ";" and self.in_typedef: + self.in_typedef = False + if self.prev_token.kind == "IDENT": + m = OBSOLETE_TYPE_RE_.match(self.prev_token.text) + if m and m.group(1) != "__": + self.reporter.error(self.prev_token, "use of {!r}") + self.prev_token = None + else: + self._check_prev() + + self.prev_token = tok + + def eof(self): + self._check_prev() + + def _check_prev(self): + if (self.prev_token is not None + and self.prev_token.kind == "IDENT" + and OBSOLETE_TYPE_RE_.match(self.prev_token.text)): + self.reporter.error(self.prev_token, "use of {!r}") + +class ObsoletePublicDefinitionsAllowed(ConstructChecker): + """Allow definitions of the public versions of the obsolete + typedefs. Only specific forms of definition are allowed: + + typedef __obsolete obsolete; // identifiers must agree + typedef __uintN_t u_intN_t; // N must agree + typedef unsigned long int ulong; + typedef unsigned short int ushort; + typedef unsigned int uint; + """ + def __init__(self, reporter): + super().__init__(reporter) + self.typedef_tokens = [] + + def examine(self, tok): + if tok.kind in ("WHITESPACE", "BLOCK_COMMENT", + "LINE_COMMENT", "NL", "ESCNL"): + pass + + elif (tok.kind == "IDENT" and tok.text == "typedef" + and tok.context is None): + if self.typedef_tokens: + self.reporter.error(tok, "typedef inside typedef") + self._reset() + self.typedef_tokens.append(tok) + + elif tok.kind == "PUNCTUATOR" and tok.text == ";": + self._finish() + + elif self.typedef_tokens: + self.typedef_tokens.append(tok) + + def eof(self): + self._reset() + + def _reset(self): + while self.typedef_tokens: + tok = self.typedef_tokens.pop(0) + if tok.kind == "IDENT" and OBSOLETE_TYPE_RE_.match(tok.text): + self.reporter.error(tok, "use of {!r}") + + def _finish(self): + if not self.typedef_tokens: return + if self.typedef_tokens[-1].kind == "IDENT": + m = OBSOLETE_TYPE_RE_.match(self.typedef_tokens[-1].text) + if m: + if self._permissible_public_definition(m): + self.typedef_tokens.clear() + self._reset() + + def _permissible_public_definition(self, m): + if m.group(1) == "__": return False + name = m.group(2) + toks = self.typedef_tokens + ntok = len(toks) + if ntok == 3 and toks[1].kind == "IDENT": + defn = toks[1].text + n = OBSOLETE_TYPE_RE_.match(defn) + if n and n.group(1) == "__" and n.group(2) == name: + return True + + if (name[:5] == "u_int" and name[-2:] == "_t" + and defn[:6] == "__uint" and defn[-2:] == "_t" + and name[5:-2] == defn[6:-2]): + return True + + return False + + if (name == "ulong" and ntok == 5 + and toks[1].kind == "IDENT" and toks[1].text == "unsigned" + and toks[2].kind == "IDENT" and toks[2].text == "long" + and toks[3].kind == "IDENT" and toks[3].text == "int"): + return True + + if (name == "ushort" and ntok == 5 + and toks[1].kind == "IDENT" and toks[1].text == "unsigned" + and toks[2].kind == "IDENT" and toks[2].text == "short" + and toks[3].kind == "IDENT" and toks[3].text == "int"): + return True + + if (name == "uint" and ntok == 4 + and toks[1].kind == "IDENT" and toks[1].text == "unsigned" + and toks[2].kind == "IDENT" and toks[2].text == "int"): + return True + + return False + +def ObsoleteTypedefChecker(reporter, fname): + """Factory: produce an instance of the appropriate + obsolete-typedef checker for FNAME.""" + + # The obsolete rpc/ and rpcsvc/ headers are allowed to use the + # obsolete types, because it would be more trouble than it's + # worth to remove them from headers that we intend to stop + # installing eventually anyway. + if (fname.startswith("rpc/") + or fname.startswith("rpcsvc/") + or "/rpc/" in fname + or "/rpcsvc/" in fname): + return NoCheck(reporter) + + # bits/types.h is allowed to define the __-versions of the + # obsolete types. + if (fname == "bits/types.h" + or fname.endswith("/bits/types.h")): + return ObsoletePrivateDefinitionsAllowed(reporter) + + # sys/types.h is allowed to use the __-versions of the + # obsolete types, but only to define the unprefixed versions. + if (fname == "sys/types.h" + or fname.endswith("/sys/types.h")): + return ObsoletePublicDefinitionsAllowed(reporter) + + return ObsoleteNotAllowed(reporter) + +# +# Master control +# + +class HeaderChecker: + """Perform all of the checks on each header. This is also the + "reporter" object expected by tokenize_c and ConstructChecker. + """ + def __init__(self): + self.fname = None + self.status = 0 + + def error(self, tok, message): + self.status = 1 + if '{!r}' in message: + message = message.format(tok.text) + sys.stderr.write("{}:{}:{}: error: {}\n".format( + self.fname, tok.line, tok.column, message)) + + def check(self, fname): + self.fname = fname + try: + with open(fname, "rt") as fp: + contents = fp.read() + except OSError as e: + sys.stderr.write("{}: {}\n".format(fname, e.strerror)) + self.status = 1 + return + + typedef_checker = ObsoleteTypedefChecker(self, self.fname) + + for tok in tokenize_c(contents, self): + typedef_checker.examine(tok) + +def main(): + ap = argparse.ArgumentParser(description=__doc__) + ap.add_argument("headers", metavar="header", nargs="+", + help="one or more headers to scan for obsolete constructs") + args = ap.parse_args() + + checker = HeaderChecker() + for fname in args.headers: + # Headers whose installed name begins with "finclude/" contain + # Fortran, not C, and this program should completely ignore them. + if not (fname.startswith("finclude/") or "/finclude/" in fname): + checker.check(fname) + sys.exit(checker.status) + +main() |