RFR: 8247396: PCH should be disabled for opt-size feature with clang after JDK-8246751

[Erik Joelsson]

Hello,

For this to work in the current set of elifs you need to either combine 
the checks for clang and opt-size into one conditional, so the final 
else is still reached if toolchain is clang but opt-size is not present, 
or add another else to the nested if statement like in the block above 
for gcc. I prefer the former in this case.

/Erik

On 2020-06-11 06:10, jiefu(傅杰) wrote:
> Hi Erik,
>
> Thanks for your review and valuable comments.
>
> Updated: http://cr.openjdk.java.net/~jiefu/8247396/webrev.01/
>
> Please review it and give me some adviece.
>
> Thanks a lot.
> Best regards,
> Jie
>
> On 2020/6/11, 8:37 PM, "Erik Joelsson" <erik.joelsson at oracle.com> wrote:
>
>      I agree with the assessment, but I think the disabling should happen in
>      configure. That way the configure log can accurately tell the user why
>      it was disabled. This can be done by just adding another elif in
>      BPERF_SETUP_PRECOMPILED_HEADERS. To check for a jvm feature in
>      configure, you can use JVM_FEATURES_IS_ACTIVE(opt-size).
>      
>      /Erik
>      
>      On 2020-06-11 02:25, jiefu(傅杰) wrote:
>      > Hi all,
>      >
>      > JBS:    https://bugs.openjdk.java.net/browse/JDK-8247396
>      > Webrev: http://cr.openjdk.java.net/~jiefu/8247396/webrev.00/
>      >
>      > -O3 is used for clang on MacOS after JDK-8246751.
>      > But it breaks the builds of VMs with opt-size feature when PCH is enabled.
>      >
>      > The reason is that the PCH was built with -Os while some other files were built with -O3, which causes an error with clang.
>      > It would be better to disable the PCH for opt-size builds.
>      >
>      > Thanks a lot.
>      > Best regards,
>      > Jie
>      
>      
>