(Condy) Folded of local variables are still considered when calculating the max number of local vars of a method

[Brian Goetz]

It sounds like the dead-code elimination is done after we construct the 
LV tables?

On 9/2/2018 1:58 PM, Remi Forax wrote:
> Hi all,
> while trying to reproduce a bug in ASM using the constant API + Intrinsics.ldc, i've spot a discrepancy,
> using the follwing example,
>
> package jdk12;
>
> import java.lang.constant.ClassDesc;
> import java.lang.constant.DirectMethodHandleDesc.Kind;
> import java.lang.constant.DynamicConstantDesc;
> import java.lang.constant.MethodHandleDesc;
> import java.lang.constant.MethodTypeDesc;
> import java.lang.invoke.Intrinsics;
> import java.lang.invoke.MethodHandles.Lookup;
>
> public class ConstantDynamicExample {
>    public static long primitiveExample() {
>      MethodTypeDesc methodDescriptor = MethodTypeDesc.ofDescriptor("(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/Class;)J");
>      DynamicConstantDesc<Long> dynamicConstant = DynamicConstantDesc.of(
>          MethodHandleDesc.of(Kind.STATIC, ClassDesc.of("jdk12.ConstantDynamicExample"), "bsm", methodDescriptor));
>      return Intrinsics.ldc(dynamicConstant);
>    }
>
>    private static long bsm(Lookup lookup, String name, Class<?> type) {
>      return 3L;
>    }
>    
>    public static void main(String[] args) {
>      System.out.println(primitiveExample());
>    }
> }
>
>
> Using javap, you can see that the dynamicConstant is folded but the number of local variable (locals=2) still count the variables that doesn't exist anymore
>
>   public static long primitiveExample();
>      descriptor: ()J
>      flags: (0x0009) ACC_PUBLIC, ACC_STATIC
>      Code:
>        stack=2, locals=2, args_size=0
>           0: ldc2_w        #2                  // Dynamic #0:_:J
>           3: lreturn
>        LineNumberTable:
>          line 43: 0
>
> regards,
> Rémi