RFR: 8261211: Zero: alpha builds fail with '-fstack-protector not supported for this target' [v2]

[Aleksey Shipilev]

On Fri, 5 Feb 2021 10:19:18 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

>> Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Drop -Werror
>
> Changes requested by ihse (Reviewer).

> Apparently so. But then again all platforms except alpha has this in recent gcc versions, so I think it was an understandable misunderstanding. :) Do anyone build alpha at any regularity at all? I thought Debian at least did that. But this must have been broken for quite some time?

I discovered it after adding Alpha builds to my CIs, which are supposed to cover me for ongoing Zero maintenance work. So I would be building those regularly :) 

I just browsed Debian's build logs, and I believe Alpha builds are done with GCC 10 there (is that right, @glaubitz?). My CIs build with GCC 9. So maybe this patch would become unnecessary when we move to GCC 10 as default. I can work this around for Alpha builds in my CI, but I was hoping to have the least magical incantation to build cleanly.

> make/autoconf/flags-cflags.m4 line 209:
> 
>> 207:       # Not all versions of gcc support -fstack-protector-all
>> 208:       STACK_PROTECTOR_ALL_CFLAG="-fstack-protector-all"
>> 209:       FLAGS_COMPILER_CHECK_ARGUMENTS(ARGUMENT: [STACK_PROTECTOR_ALL_CFLAG -Werror],
> 
> You don't need to add `-Werror` anymore, `$CFLAGS_WARNINGS_ARE_ERRORS` is now added automatically by `FLAGS_COMPILER_CHECK_ARGUMENTS` (as it should have been from the beginning).

Fixed!

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PR: https://git.openjdk.java.net/jdk/pull/2423