RFR: 8301997: Move method resolution information out of the cpCache [v4]

Fei Yang fyang at openjdk.org
Fri Oct 27 06:56:50 UTC 2023


On Mon, 23 Oct 2023 19:53:54 GMT, Matias Saavedra Silva <matsaave at openjdk.org> wrote:

>> The current structure used to store the resolution information for methods, ConstantPoolCacheEntry, is difficult to interpret due to its ambigious fields f1 and f2. This structure previously held information for fields, methods, and invokedynamic calls which were all encoded into f1 and f2. Currently this structure only handles method entries, but it remains obtuse and inconsistent with recent changes. 
>> 
>> This enhancement introduces a new data structure that stores the necessary resolution data in an intuitive an extensible manner. These resolved entries are stored in an array inside the constant pool cache in a very similar manner to invokedynamic entries in JDK-8301995.
>> 
>> Instances of ConstantPoolCache entry related to field resolution have been replaced with the new ResolvedMethodEntry, and ConstantPoolCacheEntry has been removed entirely. The class ResolvedMethodEntry holds resolution information for all types of invoke calls besides invokedynamic, and thus has fields that may be unused depending on the invoke code. 
>> 
>> To streamline the review, please consider these major areas that have been changed:
>> 1. ResolvedMethodEntry class
>> 2. Rewriter for initialization of the structure
>> 3. cpCache for resolution
>> 4. InterpreterRuntime, linkResolver, and templateTable
>> 5. JVMCI
>> 6. SA
>> 
>> Verified with tier 1-9 tests.
>> 
>> This change supports the following platforms: x86, aarch64
>
> Matias Saavedra Silva has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains six commits:
> 
>  - Merge branch 'master' into method_entry_8301997
>  - Added asserts for getters and fixed printing
>  - Removed dead code in interpreters
>  - Removed unused structures, improved set_method_handle and appendix_if_resolved
>  - Removed some comments and relocated code
>  - 8301997: Move method resolution information out of the cpCache

src/hotspot/cpu/aarch64/templateTable_aarch64.cpp line 3306:

> 3304:   // x86 uses a shift and mask or wings it with a shift plus assert
> 3305:   // the mask is not needed. aarch64 just uses bitfield extract
> 3306:   __ ubfxw(rscratch2, flags, ConstantPoolCacheEntry::tos_state_shift,  ConstantPoolCacheEntry::tos_state_bits);

Nit: You might want to remove the preceding 3-line code comment together.

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PR Review Comment: https://git.openjdk.org/jdk/pull/15455#discussion_r1374143907


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