jdk8u: -Wno-regsiter to support newer compilers

[Zdeněk Žamberský]

Hello,

this is known issue, which should get fixed by JDK-8281096:
https://github.com/openjdk/jdk8u-dev/pull/357

(see also: https://github.com/openjdk/jdk8u-dev/pull/508)

TLDR:
Jdk 8 explicitly specifies older c++ version (gnu++98, which not yet 
deprecated
'register' keyword), but flags are not propagated to ADLC build due to bug.
(correct me, if I am wrong)


When it comes to Adoptium, I don't know exactly, but I think they are using
older compiler, which uses older c++ standard by default.

On 06. 08. 24 18:37, Magnus Ihse Bursie wrote:
> Hi Elazar,
>
> I see that you never got any replies here. I suggest that you re-ask 
> your question on the jdk8u mailing list instead (cc'd).
>
> /Magnus
>
> On 2024-07-19 16:20, Elazar Leibovich wrote:
>> When trying to compile the latest jdk8u on linux I get failures over 
>> warnings with the register keywords.
>>
>> I'm using https://github.com/openjdk/jdk8u-dev.git which seems to be 
>> pretty up to date (I'm using master), and last commit is less than 
>> two days ago.
>>
>> This is a workaround I had to use:
>> diff --git a/hotspot/make/linux/makefiles/gcc.make 
>> b/hotspot/make/linux/makefiles/gcc.make
>> index 7dde7f0963..81f156574a 100644
>> --- a/hotspot/make/linux/makefiles/gcc.make
>> +++ b/hotspot/make/linux/makefiles/gcc.make
>> @@ -202,7 +202,7 @@ else
>>  endif
>>
>>  # Compiler warnings are treated as errors
>> -WARNINGS_ARE_ERRORS = -Werror
>> +WARNINGS_ARE_ERRORS = -Werror -Wno-register
>>
>> But I guess the best solution is to remove the register keywords from 
>> the codebase.
>>
>> How is adoptium building it? Does it use specific compiler? Is the 
>> supported compiler documented anywhere?
>>
>> FTR using temurin-build repository and scripts, fails for other 
>> reasons, and fails even with -D/--podman docker containers.
>>
>> This patch builds it with centos stream 9 on amd64.
>>
>> Am I doing something wrong? What's the recommended way of building jdk8?
>>
>> Thanks,
>> Elazar Leibovich
>

-- 
Zdeněk Žamberský
OpenJDK QE
Red Hat