Description Rémi Forax 2012-07-18 09:05:26 EDT

Build Identifier: I20120608-1400

Eclipse compiler fails to implement the JLS regarding to the way MethodHandle.invokeExact should be compiled (section 15.12.3 of JLS7).

The bug seams to only occur if invokeExact (and I suppose invoke) takes an array of Object as parameters.





Reproducible: Always

Steps to Reproduce:
try to compile the following program using eclipse, it currently fails at runtime because invokeExact signature is compiled as (Object[])Object instead of (Object[])I.

import static java.lang.invoke.MethodHandles.*; 

import java.lang.invoke.MethodHandle;

public class EclipseInvokeExactBug {
  public static void main(String[] args) throws Throwable {
    MethodHandle mh = dropArguments(insertArguments(identity(int.class), 0, 42), 0, Object[].class);
    int value = (int)mh.invokeExact(new Object[0]);
  }
}

Here is the corresponding bytecode:
public static void main(java.lang.String[]) throws java.lang.Throwable;
    Code:
       0: getstatic     #19                 // Field java/lang/Integer.TYPE:Ljava/lang/Class;
       3: invokestatic  #25                 // Method java/lang/invoke/MethodHandles.identity:(Ljava/lang/Class;)Ljava/lang/invoke/MethodHandle;
       6: iconst_0      
       7: iconst_1      
       8: anewarray     #3                  // class java/lang/Object
      11: dup           
      12: iconst_0      
      13: bipush        42
      15: invokestatic  #31                 // Method java/lang/Integer.valueOf:(I)Ljava/lang/Integer;
      18: aastore       
      19: invokestatic  #35                 // Method java/lang/invoke/MethodHandles.insertArguments:(Ljava/lang/invoke/MethodHandle;I[Ljava/lang/Object;)Ljava/lang/invoke/MethodHandle;
      22: iconst_0      
      23: iconst_1      
      24: anewarray     #39                 // class java/lang/Class
      27: dup           
      28: iconst_0      
      29: ldc           #41                 // class "[Ljava/lang/Object;"
      31: aastore       
      32: invokestatic  #43                 // Method java/lang/invoke/MethodHandles.dropArguments:(Ljava/lang/invoke/MethodHandle;I[Ljava/lang/Class;)Ljava/lang/invoke/MethodHandle;
      35: astore_1      
      36: aload_1       
      37: iconst_0      
      38: anewarray     #3                  // class java/lang/Object
      41: invokevirtual #47                 // Method java/lang/invoke/MethodHandle.invokeExact:([Ljava/lang/Object;)Ljava/lang/Object;
      44: checkcast     #20                 // class java/lang/Integer
      47: invokevirtual #53                 // Method java/lang/Integer.intValue:()I
      50: istore_2      
      51: return        
}

as you can see the descriptor of invokevirtual at bytecode 41 is wrong.