Grab string/character lexer constants from pycparser

This commit is contained in:
Dustin Spicuzza 2022-12-10 15:16:05 -05:00
parent 03c24a2074
commit aee776072e
4 changed files with 282 additions and 15 deletions

View File

@ -1,6 +1,6 @@
cxxheaderparser license:
Copyright (c) 2020 Dustin Spicuzza <dustin@virtualroadside.com>
Copyright (c) 2020-2022 Dustin Spicuzza <dustin@virtualroadside.com>
All rights reserved.
Redistribution and use in source and binary forms, with or without
@ -102,3 +102,31 @@ THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-----------------------------------------------------------------------------
pycparser -- A C parser in Python
Copyright (c) 2008-2022, Eli Bendersky
All rights reserved.
Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
* Neither the name of the copyright holder nor the names of its contributors may
be used to endorse or promote products derived from this software without
specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

View File

@ -61,6 +61,10 @@ PhonyEnding.lexpos = 0
class Lexer:
"""
This lexer is a combination of pieces from the PLY lexers that CppHeaderParser
and pycparser have.
"""
keywords = {
"__attribute__",
@ -144,15 +148,33 @@ class Lexer:
}
tokens = [
"NUMBER",
"FLOAT_NUMBER",
# constants
"FLOAT_CONST",
"HEX_FLOAT_CONST",
"INT_CONST_HEX",
"INT_CONST_BIN",
"INT_CONST_OCT",
"INT_CONST_DEC",
"INT_CONST_CHAR",
"CHAR_CONST",
"WCHAR_CONST",
"U8CHAR_CONST",
"U16CHAR_CONST",
"U32CHAR_CONST",
# String literals
"STRING_LITERAL",
"WSTRING_LITERAL",
"U8STRING_LITERAL",
"U16STRING_LITERAL",
"U32STRING_LITERAL",
#
"NAME",
# Comments
"COMMENT_SINGLELINE",
"COMMENT_MULTILINE",
"PRECOMP_MACRO",
# misc
"DIVIDE",
"CHAR_LITERAL",
"STRING_LITERAL",
"NEWLINE",
"ELLIPSIS",
"DBL_LBRACKET",
@ -189,9 +211,216 @@ class Lexer:
".",
]
#
# Regexes for use in tokens (taken from pycparser)
#
hex_prefix = "0[xX]"
hex_digits = "[0-9a-fA-F]+"
bin_prefix = "0[bB]"
bin_digits = "[01]+"
# integer constants (K&R2: A.2.5.1)
integer_suffix_opt = (
r"(([uU]ll)|([uU]LL)|(ll[uU]?)|(LL[uU]?)|([uU][lL])|([lL][uU]?)|[uU])?"
)
decimal_constant = (
"(0" + integer_suffix_opt + ")|([1-9][0-9]*" + integer_suffix_opt + ")"
)
octal_constant = "0[0-7]*" + integer_suffix_opt
hex_constant = hex_prefix + hex_digits + integer_suffix_opt
bin_constant = bin_prefix + bin_digits + integer_suffix_opt
bad_octal_constant = "0[0-7]*[89]"
# character constants (K&R2: A.2.5.2)
# Note: a-zA-Z and '.-~^_!=&;,' are allowed as escape chars to support #line
# directives with Windows paths as filenames (..\..\dir\file)
# For the same reason, decimal_escape allows all digit sequences. We want to
# parse all correct code, even if it means to sometimes parse incorrect
# code.
#
# The original regexes were taken verbatim from the C syntax definition,
# and were later modified to avoid worst-case exponential running time.
#
# simple_escape = r"""([a-zA-Z._~!=&\^\-\\?'"])"""
# decimal_escape = r"""(\d+)"""
# hex_escape = r"""(x[0-9a-fA-F]+)"""
# bad_escape = r"""([\\][^a-zA-Z._~^!=&\^\-\\?'"x0-7])"""
#
# The following modifications were made to avoid the ambiguity that allowed backtracking:
# (https://github.com/eliben/pycparser/issues/61)
#
# - \x was removed from simple_escape, unless it was not followed by a hex digit, to avoid ambiguity with hex_escape.
# - hex_escape allows one or more hex characters, but requires that the next character(if any) is not hex
# - decimal_escape allows one or more decimal characters, but requires that the next character(if any) is not a decimal
# - bad_escape does not allow any decimals (8-9), to avoid conflicting with the permissive decimal_escape.
#
# Without this change, python's `re` module would recursively try parsing each ambiguous escape sequence in multiple ways.
# e.g. `\123` could be parsed as `\1`+`23`, `\12`+`3`, and `\123`.
simple_escape = r"""([a-wyzA-Z._~!=&\^\-\\?'"]|x(?![0-9a-fA-F]))"""
decimal_escape = r"""(\d+)(?!\d)"""
hex_escape = r"""(x[0-9a-fA-F]+)(?![0-9a-fA-F])"""
bad_escape = r"""([\\][^a-zA-Z._~^!=&\^\-\\?'"x0-9])"""
escape_sequence = (
r"""(\\(""" + simple_escape + "|" + decimal_escape + "|" + hex_escape + "))"
)
# This complicated regex with lookahead might be slow for strings, so because all of the valid escapes (including \x) allowed
# 0 or more non-escaped characters after the first character, simple_escape+decimal_escape+hex_escape got simplified to
escape_sequence_start_in_string = r"""(\\[0-9a-zA-Z._~!=&\^\-\\?'"])"""
cconst_char = r"""([^'\\\n]|""" + escape_sequence + ")"
char_const = "'" + cconst_char + "'"
wchar_const = "L" + char_const
u8char_const = "u8" + char_const
u16char_const = "u" + char_const
u32char_const = "U" + char_const
multicharacter_constant = "'" + cconst_char + "{2,4}'"
unmatched_quote = "('" + cconst_char + "*\\n)|('" + cconst_char + "*$)"
bad_char_const = (
r"""('"""
+ cconst_char
+ """[^'\n]+')|('')|('"""
+ bad_escape
+ r"""[^'\n]*')"""
)
# string literals (K&R2: A.2.6)
string_char = r"""([^"\\\n]|""" + escape_sequence_start_in_string + ")"
string_literal = '"' + string_char + '*"'
wstring_literal = "L" + string_literal
u8string_literal = "u8" + string_literal
u16string_literal = "u" + string_literal
u32string_literal = "U" + string_literal
bad_string_literal = '"' + string_char + "*" + bad_escape + string_char + '*"'
# floating constants (K&R2: A.2.5.3)
exponent_part = r"""([eE][-+]?[0-9]+)"""
fractional_constant = r"""([0-9]*\.[0-9]+)|([0-9]+\.)"""
floating_constant = (
"(((("
+ fractional_constant
+ ")"
+ exponent_part
+ "?)|([0-9]+"
+ exponent_part
+ "))[FfLl]?)"
)
binary_exponent_part = r"""([pP][+-]?[0-9]+)"""
hex_fractional_constant = (
"(((" + hex_digits + r""")?\.""" + hex_digits + ")|(" + hex_digits + r"""\.))"""
)
hex_floating_constant = (
"("
+ hex_prefix
+ "("
+ hex_digits
+ "|"
+ hex_fractional_constant
+ ")"
+ binary_exponent_part
+ "[FfLl]?)"
)
t_ignore = " \t\r?@\f"
t_NUMBER = r"[0-9][0-9XxA-Fa-f]*"
t_FLOAT_NUMBER = r"[-+]?[0-9]*\.[0-9]+([eE][-+]?[0-9]+)?"
# The following floating and integer constants are defined as
# functions to impose a strict order (otherwise, decimal
# is placed before the others because its regex is longer,
# and this is bad)
#
@TOKEN(floating_constant)
def t_FLOAT_CONST(self, t: LexToken) -> LexToken:
return t
@TOKEN(hex_floating_constant)
def t_HEX_FLOAT_CONST(self, t: LexToken) -> LexToken:
return t
@TOKEN(hex_constant)
def t_INT_CONST_HEX(self, t: LexToken) -> LexToken:
return t
@TOKEN(bin_constant)
def t_INT_CONST_BIN(self, t: LexToken) -> LexToken:
return t
@TOKEN(bad_octal_constant)
def t_BAD_CONST_OCT(self, t: LexToken) -> None:
msg = "Invalid octal constant"
self._error(msg, t)
@TOKEN(octal_constant)
def t_INT_CONST_OCT(self, t: LexToken) -> LexToken:
return t
@TOKEN(decimal_constant)
def t_INT_CONST_DEC(self, t: LexToken) -> LexToken:
return t
# Must come before bad_char_const, to prevent it from
# catching valid char constants as invalid
#
@TOKEN(multicharacter_constant)
def t_INT_CONST_CHAR(self, t: LexToken) -> LexToken:
return t
@TOKEN(char_const)
def t_CHAR_CONST(self, t: LexToken) -> LexToken:
return t
@TOKEN(wchar_const)
def t_WCHAR_CONST(self, t: LexToken) -> LexToken:
return t
@TOKEN(u8char_const)
def t_U8CHAR_CONST(self, t: LexToken) -> LexToken:
return t
@TOKEN(u16char_const)
def t_U16CHAR_CONST(self, t: LexToken) -> LexToken:
return t
@TOKEN(u32char_const)
def t_U32CHAR_CONST(self, t: LexToken) -> LexToken:
return t
@TOKEN(unmatched_quote)
def t_UNMATCHED_QUOTE(self, t: LexToken) -> None:
msg = "Unmatched '"
self._error(msg, t)
@TOKEN(bad_char_const)
def t_BAD_CHAR_CONST(self, t: LexToken) -> None:
msg = "Invalid char constant %s" % t.value
self._error(msg, t)
@TOKEN(wstring_literal)
def t_WSTRING_LITERAL(self, t: LexToken) -> LexToken:
return t
@TOKEN(u8string_literal)
def t_U8STRING_LITERAL(self, t: LexToken) -> LexToken:
return t
@TOKEN(u16string_literal)
def t_U16STRING_LITERAL(self, t: LexToken) -> LexToken:
return t
@TOKEN(u32string_literal)
def t_U32STRING_LITERAL(self, t: LexToken) -> LexToken:
return t
# unmatched string literals are caught by the preprocessor
@TOKEN(bad_string_literal)
def t_BAD_STRING_LITERAL(self, t):
msg = "String contains invalid escape code"
self._error(msg, t)
@TOKEN(r"[A-Za-z_~][A-Za-z0-9_]*")
def t_NAME(self, t: LexToken) -> LexToken:
@ -222,7 +451,6 @@ class Lexer:
return t
t_DIVIDE = r"/(?!/)"
t_CHAR_LITERAL = "'.'"
t_ELLIPSIS = r"\.\.\."
t_DBL_LBRACKET = r"\[\["
t_DBL_RBRACKET = r"\]\]"
@ -232,9 +460,7 @@ class Lexer:
t_SHIFT_LEFT = r"<<"
# SHIFT_RIGHT introduces ambiguity
# found at http://wordaligned.org/articles/string-literals-and-regular-expressions
# TODO: This does not work with the string "bla \" bla"
t_STRING_LITERAL = r'"([^"\\]|\\.)*"'
t_STRING_LITERAL = string_literal
# Found at http://ostermiller.org/findcomment.html
@TOKEN(r"/\*([^*]|[\r\n]|(\*+([^*/]|[\r\n])))*\*+/\n?")

View File

@ -1171,7 +1171,7 @@ class CxxParser:
def _parse_bitfield(self) -> int:
# is a integral constant expression... for now, just do integers
tok = self._next_token_must_be("NUMBER")
tok = self._next_token_must_be("INT_CONST_DEC")
return int(tok.value)
def _parse_field(

View File

@ -5,11 +5,24 @@ from .types import Token
# key: token type, value: (left spacing, right spacing)
_want_spacing = {
"NUMBER": (2, 2),
"FLOAT_NUMBER": (2, 2),
"FLOAT_CONST": (2, 2),
"HEX_FLOAT_CONST": (2, 2),
"INT_CONST_HEX": (2, 2),
"INT_CONST_BIN": (2, 2),
"INT_CONST_OCT": (2, 2),
"INT_CONST_DEC": (2, 2),
"INT_CONST_CHAR": (2, 2),
"NAME": (2, 2),
"CHAR_LITERAL": (2, 2),
"CHAR_CONST": (2, 2),
"WCHAR_CONST": (2, 2),
"U8CHAR_CONST": (2, 2),
"U16CHAR_CONST": (2, 2),
"U32CHAR_CONST": (2, 2),
"STRING_LITERAL": (2, 2),
"WSTRING_LITERAL": (2, 2),
"U8STRING_LITERAL": (2, 2),
"U16STRING_LITERAL": (2, 2),
"U32STRING_LITERAL": (2, 2),
"ELLIPSIS": (2, 2),
">": (0, 2),
")": (0, 1),