On Wed, 28 Aug 2024 22:38:11 GMT, Chen Liang <li...@openjdk.org> wrote:
>> A small optimization to reduce the code size of StackMapGenerator.Frame's
>> pushStack and setLocalsFromArg methods
>>
>> Below is the compiler log of C2
>>
>>
>> # baseline
>> jdk.internal.classfile.impl.StackMapGenerator$Frame::pushStack (27 bytes)
>> failed to inline: callee uses too much stack
>> jdk.internal.classfile.impl.StackMapGenerator$Frame::pushStack (46 bytes)
>> failed to inline: callee is too large
>> jdk.internal.classfile.impl.StackMapGenerator$Frame::pushStack (183 bytes)
>> failed to inline: callee is too large
>> jdk.internal.classfile.impl.StackMapGenerator$Frame::setLocalsFromArg (367
>> bytes) failed to inline: callee is too large
>>
>> # current
>> jdk.internal.classfile.impl.StackMapGenerator$Frame::pushStack (26 bytes)
>> inline
>> jdk.internal.classfile.impl.StackMapGenerator$Frame::pushStack (37 bytes)
>> failed to inline: callee is too large
>> jdk.internal.classfile.impl.StackMapGenerator$Frame::pushStack (82 bytes)
>> jdk.internal.classfile.impl.StackMapGenerator$Frame::setLocalsFromArg (255
>> bytes) failed to inline: callee is too large
>
> src/java.base/share/classes/jdk/internal/classfile/impl/StackMapGenerator.java
> line 1060:
>
>> 1058: if (desc == CD_void) throw new AssertionError("Should
>> not reach here");
>> 1059: Type type;
>> 1060: if (desc instanceof PrimitiveClassDescImpl) {
>
> Can we use `desc.isPrimitive()`?
I have tried isPrimitive(). The codeSize of the virtual function call
isPrimitive() is 2 bytes larger than instanceof. The performance of instanceof
should be better. But isPrimitive() is a public API and easier to understand.
If you think isPrimitive is better, I think it's OK too.
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/20756#discussion_r1735374088
