How to avoid "Illegal type in constant pool" using "ldc_w <classname>" in Jasmin?
- by jazzdev
I'm writing a compiler that generates Jasmin code and
want to invoke a method that takes a Class as a parameter.
public class CTest
{
public static void main(String[] args)
throws Exception
{
java.lang.reflect.Array.newInstance(CTest.class, 0);
}
}
So in Jasmin, I think that should be:
.class public CTest2
.super java/lang/Object
.method public static main([Ljava/lang/String;)V
.limit stack 2
.limit locals 1
ldc_w CTest2
iconst_0
invokestatic java/lang/reflect/Array/newInstance(Ljava/lang/Class;I)Ljava/lang/Object;
pop
return
.end method
When I assemble it and run it I get:
Exception in thread "main" java.lang.VerifyError: (class: CTest2, method: main signature: ([Ljava/lang/String;)V) Illegal type in constant pool
Looking at the disassembled code for both CTest.class (the Java version)
and CTest2.class (the Jasmin version) with "javap -c -verbose"
they both appear to set up the constant pool the same way:
const #2 = class #16; // CTest
const #16 = Asciz CTest;
0: ldc_w #2; //class CTest
const #14 = Asciz CTest2;
const #17 = class #14; // CTest2
0: ldc_w #17; //class CTest2
I've fixed two bugs in Jasmin already, but I can't see what it's
doing wrong when putting the class in the constant pool for "ldc_w"
it puts classes in the constant pool for other instructions, like
"new" and "anewarray" correctly.
I've tried looking at the .class files with TraceClassVisitor in ASM,
but it doesn't dump the constant pool.
Any ideas what I can try next?
