[Bug libgcj/11780] New: Method.invoke() is very slow and leaks memory

["bryce at mckinlay dot net dot nz" <gcc-bugzilla at gcc dot gnu dot org>]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11780

           Summary: Method.invoke() is very slow and leaks memory
           Product: gcc
           Version: 3.4
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: libgcj
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: bryce at mckinlay dot net dot nz
                CC: gcc-bugs at gcc dot gnu dot org

Good performance from Method.invoke() is very important for many reflective applications.

In previous versions of libgcj security checks were not perfomed, and our performance was only a 
little worse than the JRE. A recent patch added security checks and now:

- Method.invoke is now ~10 x slower than the JRE
- Method.invoke leaks memory every time it is called

Clearly there are some simple optimizations that can be made - security check is not needed if 
method is public or accessibility flag is true. Ideally however the security check implementation 
itself should be made much faster.

Test case w/ timers follows.


import java.lang.reflect.*;

public class RefTest2
{
  static int i = 0;
  public int increment(int value)
  {
    return ++i;
  }

  public static void main(String[] args) 
    throws Exception
  {
    Method method = RefTest2.class.getMethod ("increment", 
      new Class [] { int.class });
    Object[] arg = new Object[1];
    Object value = new Integer(0);
  
    RefTest2 testObj = new RefTest2();

    while (true)
    {
      long startTime = System.currentTimeMillis();
      for (int i = 0; i < 1000000; i++)
      {
	arg[0] = value;
	value = method.invoke(testObj, arg);
      }
      System.out.println (System.currentTimeMillis() - startTime + " ms");
    }
  }
}