RFR: 8250876: Build system preparation to macos on aarch64

Mon Aug 10 09:52:19 UTC 2020

So, basically, what this patch is about is not so much "preparation for 
aarch64" as "allow cross-compile on macos"?  If I understand you 
correctly, maybe you should rename the bug?

/Magnus

On 2020-08-04 16:09, Erik Joelsson wrote:
> That's a good find! You are correct in that we haven't cross compiled 
> in any direction involving Macosx before.
>
> The preferred patch would be a bit more elaborate than that. Ideally 
> we need better control over the toolchain type of the BUILD_* compiler 
> settings. For now, I think just forcing clang/clang++ if BUILD_OS is 
> macosx is good enough.
>
> /Erik
>
> On 2020-08-04 07:02, Bernhard Urban-Forster wrote:
>> Good observation David, the change in adlc is just fixing a symptom. 
>> The difference to a regular macOS build is that technically, despite 
>> running on the same machine, it's actually cross compiling due to 
>> Rosetta being the --build=x86_64 system.
>>
>> Being a cross-compile, we therefore hit this case:
>> https://github.com/openjdk/jdk/blob/b0ceab23dd4176329cbf3a95f21e8e9ac2d8723f/make/autoconf/toolchain.m4#L905-L921 
>>
>>
>> And thus infers `/usr/bin/CC` for CXX.
>>
>> I guess cross compiling hasn't been a thing on macOS yet. I tried the 
>> following and it passes the adlc build:
>>
>> --- a/make/autoconf/toolchain.m4
>> +++ b/make/autoconf/toolchain.m4
>> @@ -917,7 +917,7 @@ AC_DEFUN_ONCE([TOOLCHAIN_SETUP_BUILD_COMPILERS],
>>       # find the build compilers in the tools dir, if needed.
>>       UTIL_REQUIRE_PROGS(BUILD_CC, [cl cc gcc])
>>       UTIL_FIXUP_EXECUTABLE(BUILD_CC)
>> -    UTIL_REQUIRE_PROGS(BUILD_CXX, [cl CC g++])
>> +    UTIL_REQUIRE_PROGS(BUILD_CXX, [clang++ cl CC g++])
>>       UTIL_FIXUP_EXECUTABLE(BUILD_CXX)
>>       UTIL_PATH_PROGS(BUILD_NM, nm gcc-nm)
>>       UTIL_FIXUP_EXECUTABLE(BUILD_NM)
>>
>> Although I'm not sure about its cleanliness :-)
>>
>> -Bernhard
>>
>> ________________________________________
>> From: build-dev <build-dev-retn at openjdk.java.net> on behalf of David 
>> Holmes <david.holmes at oracle.com>
>> Sent: Tuesday, August 4, 2020 00:46
>> To: Erik Joelsson; Vladimir Kempik; build-dev
>> Cc: Anton Kozlov; Alexander Ioffe; Andrew Brygin; Andrey Petushkov
>> Subject: Re: RFR: 8250876: Build system preparation to macos on aarch64
>>
>> 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: 
>>>> https://nam06.safelinks.protection.outlook.com/?url=http:%2F%2Fcr.openjdk.java.net%2F~vkempik%2F8250876%2Fwebrev.00%2F&data=02%7C01%7Cbeurba%40microsoft.com%7C0c8d58d5eb9144e8717f08d837ff3736%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C637320916565796801&sdata=HpXJmHXbuawTdExWESK9ssesYTuPTj7N6inXjaHfVaM%3D&reserved=0
>>>> The bug: 
>>>> https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugs.openjdk.java.net%2Fbrowse%2FJDK-8250876&data=02%7C01%7Cbeurba%40microsoft.com%7C0c8d58d5eb9144e8717f08d837ff3736%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C637320916565796801&sdata=9z2Nw8d0pa5huxUKOYorMOVy6SBo7o%2FhDT1EmgOhxQ8%3D&reserved=0
>>>>
>>>> Testing: jdk/submit.
>>>>
>>>> Thanks, Vladimir.