RFR: 8236714: enable link-time section-gc for linux to remove unused code

[Erik Joelsson]

Hello,

That's better, but there are still some issues.

flags-cflags.m4

Code is repeated in both if and else block.

jdk-options.m4

The default is now true for all platforms. I would suggest moving the 
s390x conditional down into an elif after the elif for "no".

LibCommon.gmk

Please revert whole file.

/Erik

On 2020-01-23 05:15, Baesken, Matthias wrote:
> Hi Erik,  new webrev :
>
> http://cr.openjdk.java.net/~mbaesken/webrevs/8236714.6/
>
> I moved the settings back into the  m4 files .
>
> Best regards, Matthias
>
>> Hello Matthias,
>>
>> You can keep the setting up of all the flags in flags-cflags.m4 and
>> flags-ldflags.m4 based on the value of ENABLE_LINKTIME_GC. You can also
>> default the value of this new parameter to true for s390x to keep the
>> current behavior for that platform. As it is in this patch, the JVM
>> flags for s390x are setup in configure while the JDK flags are in make,
>> which gets confusing I think.
>>
>> /Erik
>>
>>
>> On 2020-01-22 05:33, Baesken, Matthias wrote:
>>> Hi Magnus / David,  here is a new webrev :
>>>
>>>
>>> http://cr.openjdk.java.net/~mbaesken/webrevs/8236714.4/
>>>
>>>
>>> it supports now a  configure switch  --enable-linktime-gc=yes  that needs to
>> be set  to enable the link time section gc  .
>>> Exception is linuxs390x  where we already have the  feature enabled  (and
>> keep it enabled always for LIB_JVM).
>>> Best regards, Matthias
>>>
>>>
>>>
>>> From: Baesken, Matthias
>>> Sent: Freitag, 17. Januar 2020 12:44
>>> To: Magnus Ihse Bursie <magnus.ihse.bursie at oracle.com>; David Holmes
>> <david.holmes at oracle.com>; 'build-dev at openjdk.java.net' <build-
>> dev at openjdk.java.net>; 'hotspot-dev at openjdk.java.net' <hotspot-
>> dev at openjdk.java.net>
>>> Subject: RE: RFR: 8236714: enable link-time section-gc for linux to remove
>> unused code
>>>
>>>
>>>     *   Matthias: Have a look at some recently added option to get an
>> indication of the best practice in adding new options. There are some ways to
>> easily make this incorrect
>>> Hi Magnus, do you have a good/”best practice”  example  (not that I catch a
>> bad one 😉 )  ?
>>> Best regards, Matthias
>>>