RFR: 8301997: Move method resolution information out of the cpCache

[Andrew Dinn]

On Mon, 28 Aug 2023 19:49:23 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

src/hotspot/cpu/aarch64/templateTable_aarch64.cpp line 3305:

> 3303: 
> 3304:   // save 'interpreter return address'
> 3305:   __ save_bcp(); // probably don't need this

I'm not sure why you added this comment but we do need this call to `save_bcp()`. It records in the interpreter frame the 'return address' needed for re-entry into the interpreter. We cannot rely on the value cached in register rbcp remaining constant across the invoke that is about to happen.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/15455#discussion_r1362376633