RFR: 8280152: AArch64: Reuse runtime call trampolines in C2 [v2]

[Evgeny Astigeevich]

On Thu, 7 Jul 2022 21:37:36 GMT, Yi-Fan Tsai <duke at openjdk.org> wrote:

>> A trampoline stub could be generated for each runtime call. These trampolines could be duplication if the callees are the same. This change delays the stub generation and generates one stub for a distinct callee.
>> 
>> Benchmark als, chi-square, dec-tree, gauss-mix, log-regression, movie-lens, naive-bayes, page-rank, fj-means, reactors, future-genetic, mnemonics, dotty, scala-kmeans, and finagle-http in Renaissance (0.14.1) are tested. The sum of the used size of CodeHeap 'non-profiled nmethods' and CodeHeap 'profiled nmethods' shows ~4.7% reduction on average.
>
> Yi-Fan Tsai has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Rename variables

src/hotspot/share/asm/codeBuffer.hpp line 429:

> 427: 
> 428:   SharedStubToInterpRequests* _shared_stub_to_interp_requests; // used to collect requests for shared iterpreter stubs
> 429:   SharedTrampolineRequests*   _shared_trampoline_requests;     // used to collect requests for shared runtime call stubs

Please update the comment.

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PR: https://git.openjdk.org/jdk/pull/9405