RFR(S): 8234791: Fix Client VM build for x86_64 and AArch64

[Ioi Lam]

Hi Pengfei,

I have cc-ed hotspot-compiler-dev at openjdk.java.net.

Please do not push the patch until someone from hotspot-compiler-dev has 
looked at it.

Many people are away due to Thanksgiving in the US.

Thanks
- Ioi

On 11/28/19 7:56 PM, Pengfei Li (Arm Technology China) wrote:
> Hi,
>
> Please help review this small fix for 64-bit client build.
>
> Webrev: http://cr.openjdk.java.net/~pli/rfr/8234791/webrev.00/
> JBS: https://bugs.openjdk.java.net/browse/JDK-8234791
>
> Current 64-bit client VM build fails because errors occurred in dumping
> the CDS archive. In JDK 12, we enabled "Default CDS Archives"[1] which
> runs "java -Xshare:dump" after linking the JDK image. But for Client VM
> build on 64-bit platforms, the ergonomic flag UseCompressedOops is not
> set.[2] This leads to VM exits in checking the flags for dumping the
> shared archive.[3]
>
> This change removes the "#if defined" macro to make shared archive dump
> successful in 64-bit client build. By tracking the history of the macro,
> I found it is initially added as "#ifndef COMPILER1"[4] 10 years ago
> when C1 did not have a good support of compressed oops and modified to
> current shape[5] in the implementation of tiered compilation. It should
> be safe to be removed today.
>
> This patch also fixes another client build issue on AArch64.
>
> [1] http://openjdk.java.net/jeps/341
> [2] http://hg.openjdk.java.net/jdk/jdk/file/981a55672786/src/hotspot/share/runtime/arguments.cpp#l1694
> [3] http://hg.openjdk.java.net/jdk/jdk/file/981a55672786/src/hotspot/share/runtime/arguments.cpp#l3551
> [4] http://hg.openjdk.java.net/jdk8/jdk8/hotspot/rev/323bd24c6520#l11.7
> [5] http://hg.openjdk.java.net/jdk8/jdk8/hotspot/rev/d5d065957597#l86.56
>
> --
> Thanks,
> Pengfei
>