Re: [libstdc++/67015, patch] Fix regex POSIX bracket parsing

[Tim Shen <timshen at google dot com>]

On Mon, Jul 27, 2015 at 4:45 AM, Jonathan Wakely <jwakely@redhat.com> wrote:
> On 26/07/15 05:20 -0700, Tim Shen wrote:
>>
>> @@ -389,7 +391,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>> #endif
>>       }
>>
>> -      void
>> +      _StringT
>>       _M_add_collating_element(const _StringT& __s)
>>       {
>>         auto __st = _M_traits.lookup_collatename(__s.data(),
>
>
> Changing this return type is an ABI change. When compiled with older
> versions of GCC this function will not return anything, so code
> compiled with newer versions that links to that older code will read
> garbage off the stack if linked to the old version.
>
> (This isn't a problem for _M_expression_term because the return type
> is part of the mangled name for function templates).
>
> One solution would be to rename the function, so that code compiled
> with the new GCC will use the new function, not link to the old
> version that doesn't return anything.

Done by s/_M_add_collating_element/_M_add_collate_element/.


-- 
Regards,
Tim Shen

Attachment: b.diff
Description: Text document