RFR: 8339158: TypeKind add slotSize field

[Shaojin Wen]

On Wed, 28 Aug 2024 10:26:58 GMT, Shaojin Wen <duke at openjdk.org> wrote:

> Small improvement, add a final field, no need to calculate every time.

Of course, the implementation complexity of these two is different, and the code size is also different.

## codeSize

# baseline
java.lang.classfile.TypeKind::slotSize (50 bytes) 

# current
java.lang.classfile.TypeKind::slotSize (5 bytes)   inline


## bytecode
* baseline

  public int slotSize();
    Code:
       0: aload_0
       1: invokevirtual #60                 // Method ordinal:()I
       4: lookupswitch  { // 3
                     4: 44
                     5: 44
                     9: 40
               default: 48
          }
      40: iconst_0
      41: goto          49
      44: iconst_2
      45: goto          49
      48: iconst_1
      49: ireturn


* current

  public int slotSize();
    Code:
       0: aload_0
       1: getfield      #60                 // Field slotSize:I
       4: ireturn


This is not a high frequency call, a slight improvement

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PR Comment: https://git.openjdk.org/jdk/pull/20743#issuecomment-2315182651