RFR: 8250876: Build system preparation to macos on aarch64

[David Holmes]

On 3/08/2020 10:57 pm, Erik Joelsson wrote:
> Hello Vladimir,
> 
> These changes look innocent enough to me. They aren't actually adding 
> macosx-aarch64 support, they are just removing two minor (and more 
> likely OS version related) hurdles from the build. You still have to 
> provide the actual configuration on the configure command line as is 
> shown in your example. Before we can call build system support, we would 
> need configure to automatically setup those flags and add a separate 
> parameter for the JNF framework. So, given that, I don't think this 
> change warrants a JEP in itself.

Of course this change doesn't warrant a JEP in itself :) My point is 
that until we have a JEP for the platform that is being targeted then we 
shouldn't be making changes to provide support for that platform.

That said I didn't actually look at the changes but focused on the 
larger stated aim, so apologies for that.

The actual changes here are small and not obviously related to 
supporting macOS-Aarch64. But I'm unclear on this change as it affects 
all macOS builds:

   42   else ifeq ($(call isBuildOs, macosx), true)
   43     ADLC_LDFLAGS := -lc++

if this was fixing a bug as indicated, why do we not see this bug in 
regular builds?

Thanks,
David
-----


> My only complaint is that you revert jib-profiles.js. That file is only 
> used internally at Oracle. If/when we need it to support macosx-aarch64, 
> we will provide those changes.
> 
> I must say I'm happy to see you managed to get a working build 
> configuration with just this though!
> 
> /Erik
> 
> On 2020-08-01 00:24, Vladimir Kempik wrote:
>> Hello
>>
>> Please review this change for JDK-8250876
>>
>> This changeset adds support for macos/aarch64 into build system.
>> It will allow to crosscompile for macos/aarch64 using intel mac as well.
>>
>> This changeset does NOT address some arm specific issues in the macos 
>> related code, we plan to do that in s separate commit.
>>
>> An example of configure to cross-compile for macos/arm64:
>>
>> --with-boot-jdk=/path/to/java/ 
>> --with-build-jdk=/path/to/same/java/as/compiled  
>> --disable-warnings-as-errors --with-jvm-variants=zero 
>> --openjdk-target=aarch64-apple-darwin --with-extra-cflags='-arch 
>> arm64' --with-extra-ldflags='-arch arm64 
>> -F/Path/To/Folder/Containing/JNF_framework/' 
>> —with-extra-cxxflags='-arch arm64’
>>
>> JNF.framework is missing arm64 part as of next macos release, but 
>> Apple has opensourced it.
>>
>> Fix to adlc were needed due to it using symbols from stdc++ and not 
>> linking to it, so it fails when doing make images.
>>
>> The webrev: http://cr.openjdk.java.net/~vkempik/8250876/webrev.00/
>> The bug: https://bugs.openjdk.java.net/browse/JDK-8250876
>>
>> Testing: jdk/submit.
>>
>> Thanks, Vladimir.