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

[Seth Cantrell]

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
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