RFR: 8350892: [JVMCI] Align ResolvedJavaType.getInstanceFields with Class.getDeclaredFields

[Yudi Zheng]

On Fri, 28 Feb 2025 23:46:54 GMT, Doug Simon <dnsimon at openjdk.org> wrote:

> The current order of fields returned by `ResolvedJavaType.getInstanceFields` is a) not well specified and b) different than the order of fields used almost everywhere else in HotSpot. This PR aligns the order of `getInstanceFields` with `Class.getDeclaredFields()`.
> 
> It also makes `ciInstanceKlass::_nonstatic_fields` use the same order which unifies how escape analysis and deoptimization treats fields across C2 and JVMCI.

Overall looks good to me

src/hotspot/share/ci/ciInstanceKlass.cpp line 481:

> 479:   // Now sort them by offset, ascending.
> 480:   // (In principle, they could mix with superclass fields.)
> 481:   fields->sort(sort_field_by_offset);

This has no effect now, i.e., the fields were sorted already?

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Marked as reviewed by yzheng (Committer).

PR Review: https://git.openjdk.org/jdk/pull/23849#pullrequestreview-2660958414
PR Review Comment: https://git.openjdk.org/jdk/pull/23849#discussion_r1981305860