RFR: 8282218: C1: Missing side effects of dynamic class loading during constant linkage [v2]

[Vladimir Ivanov]

On Fri, 6 May 2022 20:23:48 GMT, Vladimir Ivanov <vlivanov at openjdk.org> wrote:

>> (The problem is similar to JDK-8282194, but with class loading this time.)
>> 
>> C1 handles unresolved constants by performing constant resolution at runtime and then putting the constant value into the generated code by patching it. But it treats the not-yet-resolved value as a pure constant without any side effects.
>> 
>> It's not the case for constants which trigger class loading using custom class loaders. (All non-String constants do that.)
>> 
>> There are no guarantees that there are no side effects during class loading, so C1 has to be conservative.
>> 
>> Proposed fix kills memory after accessing not-yet-loaded constant in the context of any non-trusted class loader.
>> 
>> Testing: hs-tier1 - hs-tier4
>
> Vladimir Ivanov has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:
> 
>  - helper method to access constant pool tag
>  - Merge branch 'master' into 8282218.c1.class_loading
>  - 8282218: C1: Missing side effects of dynamic class loading during constant linkage

Thanks for the reviews, Vladimir & Tobias.

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PR: https://git.openjdk.java.net/jdk/pull/7612