support C/C++ identifiers named with non-ASCII characters
Simon Marchi
simark@simark.ca
Mon May 21 14:21:00 GMT 2018
On 2018-05-21 04:52 AM, å¼µä¿è wrote:
> Hello, team.
>
> This patch fixes the bug at
> https://sourceware.org/bugzilla/show_bug.cgi?id=22973 .
>
> Here is how to test the patch:
>
> Step 1. If you are using Clang or any other C compilers that have
> implemented
> support for Unicode identifiers, then create a C file with the
> following
> content:
>
> int main(int åé, char* å[])
> {
> struct é
> {
> int æ¸[3];
> } é = {100, 200, 300};
> int åº = 2;
> return 0;
> }
>
> Or if you are using GCC, create a C file with the following content as a
> workaround(GCC still doesn't actually support Unicode identifiers in
> 2018, which
> is a pity):
>
> int main(int \u53C3\u91CF, char* \u53C3[])
> {
> struct \u96C6
> {
> int \u6578[3];
> } \u96C6 = {100, 200, 300};
> int \u5E8F = 2;
> return 0;
> }
>
> Step 2. Compile the C file.
>
> Step 3. Run GDB for the compiled executable, add a breakpoint in "return 0".
>
> Step 4. Run until the breakpoint.
>
> Step 5. Test the following commands to see if they work:
> p åé
> p å
> p é
> p é.æ¸
> p é.æ¸[åº]
>
> Thanks for your review.
>
Hi Zhang,
Thanks for the patch, I tested it quickly, it seems to work as expected.
Could you please write a small test case in testsuite/gdb.base with the example
you gave, so we make sure this doesn't get broken later? If you can write it
in such a way that both clang and gcc understand it would be better, because
most people run the testuite using gcc to compile test programs.
I am not a specialist in lexing and parsing C, so can you explain quickly why
you think this is a good solution? Quickly, I understand that you change the
identifier recognition algorithm to a blacklist of characters rather than
a whitelist, so bytes that are not recognized (such as those that compose
the utf-8 encoded characters) are not rejected.
Given unlimited time, would the right solution be to use a lib to parse the
string as utf-8, and reject strings that are not valid utf-8?
Here are some not and formatting comments:
> +static bool is_identifier_separator (char);
You don't have to forward declare the function if it's not necessary.
> + /* '<' should not be a token separator, because it can be an open angle
> + bracket followed by a nested template identifier in C++. */
Please use two spaces after the final period (...C++. */).
> + if (is_identifier_separator(c))
Please use a space before the parentheses:
is_identifier_separator (c)
> + for (c = tokstart[namelen]; !is_identifier_separator(c);)
Here too.
Thanks!
Simon
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