On Fri, 29 Aug 2025 19:13:27 GMT, Chen Liang <li...@openjdk.org> wrote:
> Currently, java.lang.invoke.VarHandles$GuardMethodGenerator is in a weird
> state: when VarHandleGuards needs to be updated, we uncomment it, build JDK,
> run it as a main class, and paste the generated VarHandleGuards class.
>
> This process is complex and error-prone, and having a huge chunk of commented
> out code is not good for maintenance and verification too.
>
> Looking at how i18n and charsets generate, we can move this generator to the
> build system, and have VarHandleGuards completely automatically generated
> like the other VarHandle implementation classes or CharacterData.
>
> <details>
> <summary>
> Diff from new to old (backwards):
> </summary>
>
>
> liach@liach-Precision-5690:~$ git diff --no-index
> /home/liach/java/jdk-5/build/linux-x64/support/gensrc/java.base/java/lang/invoke/VarHandleGuards.java
>
> /home/liach/java/jdk/open/src/java.base/share/classes/java/lang/invoke/VarHandleGuards.java
> diff --git
> a/home/liach/java/jdk-5/build/linux-x64/support/gensrc/java.base/java/lang/invoke/VarHandleGuards.java
>
> b/home/liach/java/jdk/open/src/java.base/share/classes/java/lang/invoke/VarHandleGuards.java
> index 13ef65b..49408a2 100644
> ---
> a/home/liach/java/jdk-5/build/linux-x64/support/gensrc/java.base/java/lang/invoke/VarHandleGuards.java
> +++
> b/home/liach/java/jdk/open/src/java.base/share/classes/java/lang/invoke/VarHandleGuards.java
> @@ -28,8 +28,7 @@ import jdk.internal.vm.annotation.AOTSafeClassInitializer;
> import jdk.internal.vm.annotation.ForceInline;
> import jdk.internal.vm.annotation.Hidden;
>
> -// This file is generated by
> build.tools.methodhandle.VarHandleGuardMethodGenerator.
> -// Do not edit!
> +// This class is auto-generated by
> java.lang.invoke.VarHandles$GuardMethodGenerator. Do not edit.
> @AOTSafeClassInitializer
> final class VarHandleGuards {
>
>
>
> </details>
>
> Testing: java/lang/invoke.
Looks good. Suggested fixes for a few typos that I think were present in the
original documentation.
make/jdk/src/classes/build/tools/methodhandle/VarHandleGuardMethodGenerator.java
line 53:
> 51: * <p>
> 52: * The generated class essentially encapsulates pre-compiled LambdaForms,
> 53: * one for each method, for the most set of common method signatures.
Suggestion:
* one for each method, for common method signatures.
make/jdk/src/classes/build/tools/methodhandle/VarHandleGuardMethodGenerator.java
line 64:
> 62: * long, float, double), and 3 shapes then a maximum of 60 methods will be
> 63: * generated. However, the number is likely to be less since there
> 64: * be duplicate signatures.
Suggestion:
* will be duplicate signatures.
-------------
Marked as reviewed by psandoz (Reviewer).
PR Review: https://git.openjdk.org/jdk/pull/27009#pullrequestreview-3177077405
PR Review Comment: https://git.openjdk.org/jdk/pull/27009#discussion_r2316436550
PR Review Comment: https://git.openjdk.org/jdk/pull/27009#discussion_r2316438118
