RFR: 8293979: Resolve JVM_CONSTANT_Class references at CDS dump time [v2]

Ioi Lam iklam at openjdk.org
Tue Oct 18 06:56:14 UTC 2022


> Some `JVM_CONSTANT_Class` entries are guaranteed to resolve to the same value at both CDS dump time and run time:
> 
> - Classes that are resolved during `vmClasses::resolve_all()`. These classes cannot be replaced by JVMTI agents at run time.
> - Supertypes -- at run time, a class `C` can be loaded from the CDS archive only if all of `C`'s super types are also loaded from the CDS archive. Therefore, we know that a `JVM_CONSTANT_Class` reference to a supertype of `C` must resolved to the same value at both CDS dump time and run time.
> 
> By doing the resolution at dump time, we can speed up run time start-up by a little bit.
> 
> The `ClassPrelinker` class added by this PR will also be used in future REFs for pre-resolving other constant pool entries. The ultimate goal is to resolve `invokedynamic` and `invokehandle` so we can significantly improve the start-up time of features such as Lambda expressions and String concatenation. See [JDK-8293336](https://bugs.openjdk.org/browse/JDK-8293336)

Ioi Lam 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:

 - @coleenp comments
 - Merge branch 'master' into 8293979-resolve-class-references-at-dumptime
 - 8293979: Resolve JVM_CONSTANT_Class references at CDS dump time

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/10330/files
  - new: https://git.openjdk.org/jdk/pull/10330/files/48a56524..9bf8cb4c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=10330&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=10330&range=00-01

  Stats: 59174 lines in 1659 files changed: 33804 ins; 16738 del; 8632 mod
  Patch: https://git.openjdk.org/jdk/pull/10330.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10330/head:pull/10330

PR: https://git.openjdk.org/jdk/pull/10330


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