Re: [PATCH] Fix -Wattribute-alias option

[Bernd Edlinger <bernd.edlinger@hotmail.de>]

On 1/21/19 4:42 PM, Arnd Bergmann wrote:
> On Sat, Jan 19, 2019 at 11:06 AM Bernd Edlinger
> <bernd.edlinger@hotmail.de> wrote:
>>
>> Hi,
>>
>> the command line option -Wattribute-alias (w/o the "=1") is currently broken,
>> and only -Wno-attribute-alias is still working, but what is worse, is that
>> the #pragma GCC diagnostic fails to recognize the string "-Wattribute-alias",
>> as it used to do in gcc-8, which breaks the linux warning suppression macro
>> because it relies on a _Pragma to work.
> 
> I'm surprised by this, since I have not seen the warning in a while. I am
> however still using gcc-8.1 locally. Did this change later during the
> gcc-8 branch?
> 

Yes.

The -Wattribute-alias was split up in -Wattribute-alias=1 an -Wattribute-alias=2
and -Wmissing-attributes on gcc-trunk (but not in the gcc-8 branch as far as I know).

The -Wmissing-attribute also triggers in include/linux/module.h but for that one,
I will probably have to send a patch to the linux-kernel list.


$ svn log -r265980
------------------------------------------------------------------------
r265980 | msebor | 2018-11-09 18:32:52 +0100 (Fri, 09 Nov 2018) | 39 lines

PR middle-end/81824 - Warn for missing attributes with function aliases

gcc/c-family/ChangeLog:

	PR middle-end/81824
	* c-attribs.c (handle_copy_attribute): New function.

gcc/cp/ChangeLog:

	PR middle-end/81824
	* pt.c (warn_spec_missing_attributes): Move code to attribs.c.
	Call decls_mismatched_attributes.

gcc/ChangeLog:

	PR middle-end/81824
	* attribs.c (has_attribute): New helper function.
	(decls_mismatched_attributes, maybe_diag_alias_attributes): Same.
	* attribs.h (decls_mismatched_attributes): Declare.
	* cgraphunit.c (handle_alias_pairs): Call maybe_diag_alias_attributes.
	(maybe_diag_incompatible_alias): Use OPT_Wattribute_alias_.
	* common.opt (-Wattribute-alias): Take an argument.
	(-Wno-attribute-alias): New option.
	* doc/extend.texi (Common Function Attributes): Document copy.
	(Common Variable Attributes): Same.
	* doc/invoke.texi (-Wmissing-attributes): Document enhancement.
	(-Wattribute-alias): Document new option argument.

gcc/testsuite/ChangeLog:

	PR middle-end/81824
	* gcc.dg/Wattribute-alias.c: New test.
	* gcc.dg/Wmissing-attributes.c: New test.
	* gcc.dg/attr-copy.c: New test.
	* gcc.dg/attr-copy-2.c: New test.
	* gcc.dg/attr-copy-3.c: New test.
	* gcc.dg/attr-copy-4.c: New test.



Bernd.