RFR (trivial): 8219519: Remove linux_sparc.ad and linux_aarch64.ad

[Jie Fu]

Thanks Magnus and Andrew Dinn for your kind review.


On 2019年03月01日 22:47, Magnus Ihse Bursie wrote:
> On 2019-03-01 15:39, Andrew Dinn wrote:
>> On 01/03/2019 14:25, Magnus Ihse Bursie wrote:
>>> On 2019-02-27 03:25, Jie Fu wrote:
>>>> It's a bit difficult for me to test this patch since I don't have a
>>>> sparc or arm machine.
>>>> I've analyzed the adlc processing logic in
>>>> make/hotspot/gensrc/GensrcAdlc.gmk finding that ad-files under
>>>> ./src/hotspot/os_cpu/$(HOTSPOT_TARGET_OS)_$(HOTSPOT_TARGET_CPU_ARCH)
>>>> are optional.
>>> What do you mean by "optional"? The build code does this:
>>>
>>>   
>>> ##############################################################################
>>>    # Concatenate all ad source files into a single file, which will be fed to
>>>    # adlc.
>>>
>>> ...
>>>
>>>    AD_SRC_FILES := $(call uniq, $(wildcard $(foreach d, $(AD_SRC_ROOTS), \
>>>        $d/cpu/$(HOTSPOT_TARGET_CPU_ARCH)/$(HOTSPOT_TARGET_CPU).ad \
>>>        $d/cpu/$(HOTSPOT_TARGET_CPU_ARCH)/$(HOTSPOT_TARGET_CPU_ARCH).ad \
>>>       
>>> $d/os_cpu/$(HOTSPOT_TARGET_OS)_$(HOTSPOT_TARGET_CPU_ARCH)/$(HOTSPOT_TARGET_OS)_$(HOTSPOT_TARGET_CPU_ARCH).ad
>>> \
>>>      )))
>>>
>>> so it will definitely pick up both those files and use it in creating
>>> the concatenated ad file.
>> That's interesting because Pengfei Li claims he applied the patch and
>> successfully built OpenJDK on AArch64.
>>
>>
>> https://mail.openjdk.java.net/pipermail/aarch64-port-dev/2019-February/006975.html
>>
>> Does the build system actually need those files to exist when it builds
>> the concatenated file?
> No, the build system does not "need" it. If it is not there, it is not 
> included (nor reported MIA), but if it is there, it is included.
>
>>> That being said, maybe this is not the correct behavior.
>> Well, something sounds fishy.
>>
>>> I see that the linux_sparc.ad file is essentially empty, so you can
>>> probably remove that. The aarch64 file otoh seems to contain valid code.
>>> I would not presume that you can just remove it!
>> He is ok to remove it as far as any contents are concerned. Indeed, I
>> told him this was ok in a review in the above thread after Pengfei
>> reported that OpenJDK built without the file being present.
>>
>> As to the contents, the encoding defined in that file is completely
>> redundant (I don't really know how it got there as I don't believe it
>> was ever used)
>
> Ok, it might very well be the case that the file is not needed since 
> it's contents is redundant. I can't say anything about that; that's 
> the domain of the adlc experts. However, it is incorrect to claim that 
> the build does not use file in question. But from the build PoV, it's 
> perfectly fine to remove it if it's not needed. But just not on the 
> grounds that it is not used by the build system!
>
> /Magnus
>> regards,
>>
>>
>> Andrew Dinn
>> -----------
>> Senior Principal Software Engineer
>> Red Hat UK Ltd
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>