RFR: 8295102: Always load @lambda-form-invoker lines from default classlist [v4]
Ioi Lam
iklam at openjdk.org
Wed Oct 12 19:49:35 UTC 2022
> The `@lambda-form-invoker` lines in the default classlist (`$JAVA_HOME/lib/classlist`) control what lambda-form invoker methods are added to these classes that are generated during a CDS dump ([see here](https://github.com/iklam/jdk/blob/5aa997b001367141a6a2d2e69649d41b46199ab4/src/hotspot/share/cds/lambdaFormInvokers.cpp#L230)):
>
> - `java.lang.invoke.Invokers$Holder`
> - `java.lang.invoke.DirectMethodHandle$Holder`
> - `java.lang.invoke.DelegatingMethodHandle$Holder`
> - `java.lang.invoke.LambdaForm$Holder`
>
> The list of these invoker methods is generated as part of the [JDK build process](https://github.com/iklam/jdk/blob/1996f649a3a30b7ac4b547a762417f807f5fa414/make/GenerateLinkOptData.gmk#L64). They are used for invoking MethodHandles of commonly-used types, so that we can avoid generating custom LambdaForm classes.
>
> When a CDS archive is created with a non-default classlist, (e.g., `-XX:SharedClassListFile=foo.classlist`), such a classlist may not contain all the `@lambda-form-invoker` lines as in the default classlist. As a result, at runtime, more custom LambdaForm classes may be generated than necessary.
>
> The solution is to always load the `@lambda-form-invoker` lines from the default classlist, to make sure the CDS image has all the commonly-used invoker methods.
Ioi Lam has updated the pull request incrementally with one additional commit since the last revision:
rewrote test to write output to a file instead of stdout, so it will not be affected by -Xlog options
-------------
Changes:
- all: https://git.openjdk.org/jdk/pull/10639/files
- new: https://git.openjdk.org/jdk/pull/10639/files/2e6af772..fada121b
Webrevs:
- full: https://webrevs.openjdk.org/?repo=jdk&pr=10639&range=03
- incr: https://webrevs.openjdk.org/?repo=jdk&pr=10639&range=02-03
Stats: 88 lines in 3 files changed: 38 ins; 30 del; 20 mod
Patch: https://git.openjdk.org/jdk/pull/10639.diff
Fetch: git fetch https://git.openjdk.org/jdk pull/10639/head:pull/10639
PR: https://git.openjdk.org/jdk/pull/10639
More information about the hotspot-runtime-dev
mailing list