[cfe-commits] [patch] Unicode character literals for UTF-8 source encoding

Seth Cantrell seth.cantrell at gmail.com
Sun Jan 15 10:05:24 PST 2012

And here's a bug fix on top of that patch.

On Jan 12, 2012, at 7:57 PM, Seth Cantrell wrote:

> There shouldn't be since the hex escape processing limits values to what can be held given CharWidth. Removing that means I can remove the duplicate logic for calculating available_bits too. Here's a new patch 0001 that does that. I also made a small change in patch 0004.
> make test passes with these on top of commit b030b1949f "Revert accidental commit"
> On Jan 12, 2012, at 7:22 PM, Eli Friedman wrote:
>> On Wed, Jan 11, 2012 at 8:35 PM, Seth Cantrell <seth.cantrell at gmail.com> wrote:
>>> Alright, characters for which the appropriate encoding can't be represented as a single value of the appropriate type are now disallowed in character literals.
>>> so now '\u2031' is not allowed (not even in C where the literal has type int which could represent the value) and L'\U00010000' is not allowed. Also replacing these UCNs with the actual characters results in exactly the same behavior.
>> Okay, that works.
>> +  if (!HadError && (multi_char_too_long || available_bits < needed_bits)) {
>> +    PP.Diag(Loc,diag::warn_char_constant_too_large);
>> Are there actually any cases where "available_bits < needed_bits" is
>> true in the current version of your patch?
>> -Eli
>>> On Jan 10, 2012, at 3:59 PM, Eli Friedman wrote:
>>>> On Tue, Jan 10, 2012 at 4:05 AM, Seth Cantrell <seth.cantrell at gmail.com> wrote:
>>>>> whoops, that should be "anything that indicates '\U0010FFFD' isn't perfectly valid"
>>>>> Accepting larger Unicode escapes is not new with this patch (I tried the clang installed with Xcode 4.2, Apple clang version 3.0 (tags/Apple/clang-211.12) (based on LLVM 3.0svn), and `int i = '\U001F306';` gives i the value 0x001F306. Although I don't have a use-case or anything my preference is to allow the larger unicode escapes.
>>>>> If you want them excluded just let me know the ranges.
>>>> Accepting it and doing something different from gcc seems likely to
>>>> cause issues if someone is accidentally depending on gcc's behavior.
>>>> I think we should either reject it or do the same thing as gcc.
>>>> -Eli
> <0001-Improves-support-for-Unicode-in-character-literals.patch><0002-Fix-char-literal-types-in-C.patch><0003-stop-claiming-unicode-escape-sequences-are-too-long-.patch><0004-Add-and-update-tests-for-character-literals.patch>
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