On Fri, 30 Aug 2024 00:19:35 GMT, ExE Boss <d...@openjdk.org> wrote:
>> TypeKind.from(Class) is a frequently called method, which provides a
>> specialized method to improve performance.
>>
>> The following Compiler log shows that the call stack level is reduced and
>> two reference accesses (descriptorString() -> String.value) are reduced,
>> which can reduce the performance degradation caused by cache misses.
>>
>> * baseline
>>
>> @ 48 java.lang.classfile.TypeKind::from (25 bytes) inline
>> @ 1 java.lang.Class::isPrimitive (0 bytes) intrinsic
>> @ 10 java.lang.Class::descriptorString (170 bytes) failed to inline:
>> callee is too large
>> @ 15 java.lang.classfile.TypeKind::fromDescriptor (232 bytes) failed
>> to inline: callee is too large
>>
>>
>> * current
>>
>> @ 52 java.lang.classfile.TypeKind::from (103 bytes) failed to inline:
>> callee is too large
>
> src/java.base/share/classes/java/lang/classfile/TypeKind.java line 176:
>
>> 174: if (cl == double.class ) return DoubleType;
>> 175: if (cl == void.class ) return VoidType;
>> 176: else return ReferenceType;
>
> This can call `Class::isPrimitive()` to perform an implicit null check and
> short‑circuit for reference types:
> Suggestion:
>
> if (cl.isPrimitive()) { // implicit null check
> if (cl == boolean.class) return BooleanType;
> if (cl == byte.class ) return ByteType;
> if (cl == char.class ) return CharType;
> if (cl == int.class ) return IntType;
> if (cl == long.class ) return LongType;
> if (cl == short.class ) return ShortType;
> if (cl == float.class ) return FloatType;
> if (cl == double.class ) return DoubleType;
> if (cl == void.class ) return VoidType;
> }
> return ReferenceType;
https://github.com/openjdk/jdk/pull/20759#issuecomment-2317655533
Refer to @cl4es 's comment, isPrimitive is a native method and will be slow
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/20762#discussion_r1737599447
