RFR: 8344607: Link Time Optimization - basic support for clang [v4]

[Julian Waters]

On Thu, 5 Dec 2024 09:44:47 GMT, Joachim Kern <jkern at openjdk.org> wrote:

>> Matthias Baesken has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   use fat lto objects on AIX/clang
>
> make/hotspot/lib/JvmFeatures.gmk line 182:
> 
>> 180:       JVM_CFLAGS_FEATURES += -ffat-lto-objects
>> 181:     endif
>> 182:     JVM_LDFLAGS_FEATURES += $(CXX_O_FLAG_HIGHEST_JVM) -flto -fno-strict-aliasing
> 
> LGTM. ffat-lto-objects is needed on AIX, because gtest/gtestLauncher.cpp is compiled with -flto for libjvm.so, but also linked to libjvm/gtest/gtestLauncher without -flto in the link statement.

I saw this too late, shouldn't it be isTargetOs instead of isBuildOs? Or am I mistaken and only gtest is affected, hence isBuildOs? Actually I'm not sure which one would be appropriate for gtest

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PR Review Comment: https://git.openjdk.org/jdk/pull/22412#discussion_r1872611790