RFR: 8309413: General improvements to MethodTypeDesc implementation [v6]

[Mandy Chung]

On Mon, 5 Jun 2023 23:38:11 GMT, Chen Liang <liach at openjdk.org> wrote:

>> This patch aims to improve the performance of MethodTypeDesc in general, as it is currently a performance bottleneck in the Classfile API. A previous revision changed the parameter storage from an array to a list; this is dropped now. Sorry for the force push.
>> 
>> 
>> Benchmark                                                             (descString)  Mode  Cnt    Score   Error  Units
>> MethodTypeDescFactories.descriptorString   (Ljava/lang/Object;Ljava/lang/String;)I  avgt    6   27.778 ± 0.573  ns/op
>> MethodTypeDescFactories.descriptorString                                       ()V  avgt    6   13.343 ± 0.235  ns/op
>> MethodTypeDescFactories.descriptorString  ([IJLjava/lang/String;Z)Ljava/util/List;  avgt    6   40.828 ± 0.448  ns/op
>> MethodTypeDescFactories.descriptorString                     ()[Ljava/lang/String;  avgt    6   14.754 ± 0.162  ns/op
>> MethodTypeDescFactories.ofArray            (Ljava/lang/Object;Ljava/lang/String;)I  avgt    6    8.616 ± 0.132  ns/op
>> MethodTypeDescFactories.ofArray                                                ()V  avgt    6    2.146 ± 0.293  ns/op
>> MethodTypeDescFactories.ofArray           ([IJLjava/lang/String;Z)Ljava/util/List;  avgt    6   14.595 ± 0.235  ns/op
>> MethodTypeDescFactories.ofArray                              ()[Ljava/lang/String;  avgt    6    2.064 ± 0.085  ns/op
>> MethodTypeDescFactories.ofDescriptor       (Ljava/lang/Object;Ljava/lang/String;)I  avgt    6   97.077 ± 2.482  ns/op
>> MethodTypeDescFactories.ofDescriptor                                           ()V  avgt    6   13.563 ± 0.111  ns/op
>> MethodTypeDescFactories.ofDescriptor      ([IJLjava/lang/String;Z)Ljava/util/List;  avgt    6  130.543 ± 2.847  ns/op
>> MethodTypeDescFactories.ofDescriptor                         ()[Ljava/lang/String;  avgt    6   35.286 ± 0.260  ns/op
>> MethodTypeDescFactories.ofList             (Ljava/lang/Object;Ljava/lang/String;)I  avgt    6    4.156 ± 0.258  ns/op
>> MethodTypeDescFactories.ofList                                                 ()V  avgt    6    2.192 ± 0.063  ns/op
>> MethodTypeDescFactories.ofList            ([IJLjava/lang/String;Z)Ljava/util/List;  avgt    6   41.002 ± 0.235  ns/op
>> MethodTypeDescFactories.ofList                               ()[Ljava/lang/String;  avgt    6    2.200 ± 0.041  ns/op
>
> Chen Liang has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fixes for review

Thanks for the change and it looks better.   I updated the description of JDK-8309413 to make it clearer.

src/java.base/share/classes/java/lang/constant/MethodTypeDescImpl.java line 57:

> 55:      * @param validatedArgTypes {@link ClassDesc}s describing the trusted and validated parameter types
> 56:      */
> 57:     MethodTypeDescImpl(ClassDesc returnType, ClassDesc[] validatedArgTypes) {

Can make this constructor private to prevent accidental use with invalidated argTypes.   `MethodTypeDesc.of(ClassDesc returnDesc)` can call `ofTrusted` factory method.

src/java.base/share/classes/java/lang/constant/MethodTypeDescImpl.java line 106:

> 104:         } else {
> 105:             result = new MethodTypeDescImpl(returnType, ConstantUtils.EMPTY_CLASSDESC);
> 106:         }

Suggestion:

        int paramCount = types.size() - 1;
        var paramTypes = paramCount > 0 ? new ClassDesc[paramCount] : ConstantUtils.EMPTY_CLASSDESC;
        for (int i = 0; i < paramCount; i++) {
            paramTypes[i] = ClassDesc.ofDescriptor(types.get(i + 1));
        }
        result = ofTrusted(returnType, paramTypes);

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

PR Review: https://git.openjdk.org/jdk/pull/13186#pullrequestreview-1463810992
PR Review Comment: https://git.openjdk.org/jdk/pull/13186#discussion_r1218713450
PR Review Comment: https://git.openjdk.org/jdk/pull/13186#discussion_r1218736291