Re: Must unwind in gcc be ported for gcj?

[David Daney <ddaney at caviumnetworks dot com>]

On 02/23/2011 05:19 PM, majia gm wrote:
> Hi, everyone.
>
> I'm porting gcj (gcc-4.4.2) to another platform. Right now the gij
> fails when interpreting the following program.
>
> File A.java:
>
> import B;
> public class A{
>
> 	public static void main(String args[])
> 	{
> 		try{
> 			B b=(B)Class.forName("B").newInstance();
> 		catch(Exception e)
> 		{
> 			System.out.println("Cannot find Class B");
> 		}
> 	}
> }
>
> File B.java:
>
> public class B
> {}
>
> I use gdb to track gij, and I found GetCallingClass() in forName()
> returns NULL, then the bootstrap loader is used to search the Class B
> but with no result. Should the Class B has the same class loader, the
> system class loader as the Class A dose?
>
> Then I track the GetCallingClass(), and I found it needs the unwind
> function provided by gcc.  Must I port the unwind function?

Short answer: Yes.

libgcj relies internally on exception handling.

You might be able to construct simple programs that don't throw 
exceptions, but they are kind of a core language feature.

As you saw, the runtime startup code does throw and catch exceptions.

David Daney