Re: [PATCH] attribute copy, leaf, weakref and -Wmisisng-attributes (PR 88546)

[Martin Sebor <msebor@gmail.com>]

Ping: https://gcc.gnu.org/ml/gcc-patches/2018-12/msg01616.html

(The first sentence in the second paragraph below should have
read "...independently of the question whether leaf should be
accepted on extern declarations.")

On 12/21/18 4:50 PM, Martin Sebor wrote:
> The first revision of the patch was missing a test and didn't
> completely or completely correctly handle attribute noreturn.
> Attached is an update with the test included and the omission
> and bug fixed.
> 
> I think it makes sense to consider the patch independently of
> the question whether weakrefs should be extern.  That change can
> be made separately, with only minor tweaks to the attribute copy
> handling and the warning.  None of the other fixes in this patch
> (precipitated by more thorough testing) should be affected by it.
> 
> Martin
> 
> On 12/20/18 8:45 PM, Martin Sebor wrote:
>> The enhancement to detect mismatched attributes between function
>> aliases and their targets triggers (expected) warnings in GCC
>> builds due to aliases being declared with fewer attributes than
>> their targets.
>>
>> Using attribute copy as recommended to copy the attributes from
>> the target to the alias triggers another warning, this time due
>> to applying attribute leaf to static functions (the attribute
>> only applies to extern functions).  This is due to an oversight
>> in both the handler for attribute copy and in
>> the -Wmissing-attributes warning.
>>
>> In addition, the copy attribute handler doesn't account for C11
>> _Noreturn and C++ throw() specifications, both of which set
>> the corresponding tree bits but don't attach the synonymous
>> attribute to it.  This also leads to warnings in GCC builds
>> (in libgfortran).
>>
>> The attached patch corrects all of these problems: the attribute
>> copy handler to avoid copying attribute leaf to declarations of
>> static functions, and to set the noreturn and nonthrow bits, and
>> the missing attribute warning to avoid triggering for static
>> weakref aliases whose targets are decorated wiwth attribute leaf.
>>
>> With this patch, GCC should build with no -Wmissing-attributes
>> warnings.
>>
>> Tested on x86_64-linux.
>>
>> Martin
>