RFR: 8294972: Convert jdk.jlink internal plugins to use the Classfile API [v6]

[Adam Sotona]

On Tue, 14 Mar 2023 16:34:59 GMT, Chen Liang <liach at openjdk.org> wrote:

>> Adam Sotona has updated the pull request incrementally with three additional commits since the last revision:
>> 
>>  - long lines wrapped
>>  - StripJavaDebugAttributesPlugin transformation fixed
>>  - VersionPropsPlugin transformation fixed
>
> src/jdk.jlink/share/classes/jdk/tools/jlink/internal/plugins/SystemModulesPlugin.java line 614:
> 
>> 612:         private void genConstructor(ClassBuilder clb) {
>> 613:             clb.withMethod("<init>", MethodTypeDesc.of(CD_void),
>> 614:                     ACC_PUBLIC, mb -> mb.withFlags(ACC_PUBLIC).withCode( cob -> {
> 
> Why `withFlags(ACC_PUBLIC)` when the flags is already given in `withMethod`'s 3rd argument? Same for occurrences below.

It has been redundant, now more effective `withMethodBody` method is used.

> src/jdk.jlink/share/classes/jdk/tools/jlink/internal/plugins/SystemModulesPlugin.java line 615:
> 
>> 613:             clb.withMethod("<init>", MethodTypeDesc.of(CD_void),
>> 614:                     ACC_PUBLIC, mb -> mb.withFlags(ACC_PUBLIC).withCode( cob -> {
>> 615:                         cob.loadInstruction(TypeKind.ReferenceType, 0);
> 
> What's the basis for using `loadInstruction(ReferenceType, 0)` over `aload(0)`, etc.? I think, at least for constructors, we won't have other TypeKinds, so we can safely use `aload(0)` `return_()`, and this is what the original ASM code used.

The whole syntax used in `SystemModulesPlugin` deserved a refresh. `loadInstruction(ReferenceType, 0)` is a generic pattern used before more convenient `aload(0)` has been added to `CodeBuilder`.
Now it is fixed, thanks.

> src/jdk.jlink/share/classes/jdk/tools/jlink/internal/plugins/SystemModulesPlugin.java line 916:
> 
>> 914:                     sb.append("Ljava/lang/Object;");
>> 915:                 }
>> 916:                 sb.append(")Ljava/util/Set;");
> 
> The construction of the Set.of method type should move away from StringBuilder. It can be as:
> 
> var mtdArgs = new ClassDesc[size];
> Arrays.fill(mtdArgs, CD_Object);
> MethodTypeDesc mtd = MethodTypeDesc.of(CD_Set, mtdArgs);

Applied, thanks.

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PR: https://git.openjdk.org/jdk/pull/12944