gcc/contrib/unicode
David Malcolm b050653c4c contrib: add unicode/utf8-dump.py
This script may be useful when debugging issues relating to Unicode
encoding (e.g. when investigating source files with bidirectional control
characters).

It dumps a UTF-8 file as a list of numbered lines (mimicking GCC's
diagnostic output format), interleaved with lines per character showing
the Unicode codepoints, the UTF-8 encoding bytes, the name of the
character, and, where printable, the characters themselves.
The lines are printed in logical order, which may help the reader to grok
the relationship between visual and logical ordering in bi-di files.

For example:

$ cat test.c
int གྷ;
const char *אבג = "ALEF-BET-GIMEL";

$ ./contrib/unicode/utf8-dump.py test.c
   1 | int གྷ;
     |   U+0069            0x69                     LATIN SMALL LETTER I i
     |   U+006E            0x6e                     LATIN SMALL LETTER N n
     |   U+0074            0x74                     LATIN SMALL LETTER T t
     |   U+0020            0x20                                    SPACE (separator)
     |   U+0F43  0xe0 0xbd 0x83                       TIBETAN LETTER GHA གྷ
     |   U+003B            0x3b                                SEMICOLON ;
     |   U+000A            0x0a                           LINE FEED (LF) (control character)
   2 | const char *אבג = "ALEF-BET-GIMEL";
     |   U+0063            0x63                     LATIN SMALL LETTER C c
     |   U+006F            0x6f                     LATIN SMALL LETTER O o
     |   U+006E            0x6e                     LATIN SMALL LETTER N n
     |   U+0073            0x73                     LATIN SMALL LETTER S s
     |   U+0074            0x74                     LATIN SMALL LETTER T t
     |   U+0020            0x20                                    SPACE (separator)
     |   U+0063            0x63                     LATIN SMALL LETTER C c
     |   U+0068            0x68                     LATIN SMALL LETTER H h
     |   U+0061            0x61                     LATIN SMALL LETTER A a
     |   U+0072            0x72                     LATIN SMALL LETTER R r
     |   U+0020            0x20                                    SPACE (separator)
     |   U+002A            0x2a                                 ASTERISK *
     |   U+05D0       0xd7 0x90                       HEBREW LETTER ALEF א
     |   U+05D1       0xd7 0x91                        HEBREW LETTER BET ב
     |   U+05D2       0xd7 0x92                      HEBREW LETTER GIMEL ג
     |   U+0020            0x20                                    SPACE (separator)
     |   U+003D            0x3d                              EQUALS SIGN =
     |   U+0020            0x20                                    SPACE (separator)
     |   U+0022            0x22                           QUOTATION MARK "
     |   U+0041            0x41                   LATIN CAPITAL LETTER A A
     |   U+004C            0x4c                   LATIN CAPITAL LETTER L L
     |   U+0045            0x45                   LATIN CAPITAL LETTER E E
     |   U+0046            0x46                   LATIN CAPITAL LETTER F F
     |   U+002D            0x2d                             HYPHEN-MINUS -
     |   U+0042            0x42                   LATIN CAPITAL LETTER B B
     |   U+0045            0x45                   LATIN CAPITAL LETTER E E
     |   U+0054            0x54                   LATIN CAPITAL LETTER T T
     |   U+002D            0x2d                             HYPHEN-MINUS -
     |   U+0047            0x47                   LATIN CAPITAL LETTER G G
     |   U+0049            0x49                   LATIN CAPITAL LETTER I I
     |   U+004D            0x4d                   LATIN CAPITAL LETTER M M
     |   U+0045            0x45                   LATIN CAPITAL LETTER E E
     |   U+004C            0x4c                   LATIN CAPITAL LETTER L L
     |   U+0022            0x22                           QUOTATION MARK "
     |   U+003B            0x3b                                SEMICOLON ;
     |   U+000A            0x0a                           LINE FEED (LF) (control character)

Tested with Python 3.8

contrib/ChangeLog:
	* unicode/utf8-dump.py: New file.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>
2021-11-01 11:52:28 -04:00
..
from_glibc
EastAsianWidth.txt
gen_wcwidth.py
PropList.txt
README
unicode-license.txt
UnicodeData.txt
utf8-dump.py

This directory contains a mechanism for GCC to have its own internal
implementation of wcwidth functionality.  (cpp_wcwidth () in libcpp/charset.c).

The idea is to produce the necessary lookup table
(../../libcpp/generated_cpp_wcwidth.h) in a reproducible way, starting from the
following files that are distributed by the Unicode Consortium:

ftp://ftp.unicode.org/Public/UNIDATA/UnicodeData.txt
ftp://ftp.unicode.org/Public/UNIDATA/EastAsianWidth.txt
ftp://ftp.unicode.org/Public/UNIDATA/PropList.txt

These three files have been added to source control in this directory;
please see unicode-license.txt for the relevant copyright information.

In order to keep in sync with glibc's wcwidth as much as possible, it is
desirable for the logic that processes the Unicode data to be the same as
glibc's.  To that end, we also put in this directory, in the from_glibc/
directory, the glibc python code that implements their logic.  This code was
copied verbatim from glibc, and it can be updated at any time from the glibc
source code repository.  The files copied from that respository are:

localedata/unicode-gen/unicode_utils.py
localedata/unicode-gen/utf8_gen.py

And the most recent versions added to GCC are from glibc git commit:
f6032247061fb37d59565f2e9667e242c8a98e76

Finally, the script gen_wcwidth.py found here contains the GCC-specific code to
map glibc's output to the lookup tables we require.  This script should not need
to change, unless there are structural changes to the Unicode data files or to
the glibc code.

The procedure to update GCC's wcwidth tables is the following:

1.  Update the three Unicode data files from the above URLs.

2.  Update the two glibc files in from_glibc/ from glibc's git.  Update
    the commit number above in this README.

3.  Run ./gen_wcwidth.py X.Y > ../../libcpp/generated_cpp_wcwidth.h
    (where X.Y is the version of the Unicode standard corresponding to the
    Unicode data files being used, most recently, 13.0.0).

After that, GCC's wcwidth will match the most recent glibc.