status of inter-class inlining in Java?

Fri Jul 16 09:42:00 GMT 2004

Nathanael Nerode writes:
 > Consider the following sort of potential situation in libgcj:
 > 
 > class System {
 > public static final foo() {
 > B.foo();
 > }
 > }
 > 
 > class VMSystem {
 > static final foo() {
 > ...
 > }
 > }
 > 
 > Preferably VMSystem.foo should be inlined into System.foo during compilation.
 > (This would make it reasonable to merge a bunch more with Classpath, and
 > would more generally help with the indirection penalty caused by the rampant
 > forwarding methods used in much of Java.)
 > 
 > >From what I can tell, however, this doesn't seem to happen.
It works for me.
public class b
{
 public static int vvalue()
 {
 return 25;
 }
}
import b;
public class a
{
 public static void main (String[] argv)
 {
 System.out.println (b.vvalue());
 }
}
gcj a.java b.java -o bar -O3
Results in
a.main(java.lang.String[]):
.LFB4:
 pushl %ebp
.LCFI9:
 movl %esp, %ebp
.LCFI10:
 pushl %ebx
.LCFI11:
 subl 20, %esp
.LCFI12:
 movl a.class,ドル (%esp)
 call _Jv_InitClass
 movl java.lang.System.class,ドル (%esp)
 call _Jv_InitClass
 movl java.lang.System.out, %ebx
 movl b.class,ドル (%esp)
 call _Jv_InitClass
 movl 25, %edx
 movl (%ebx), %eax
 movl %edx, 4(%esp)
 movl %ebx, (%esp)
 call *100(%eax)
 addl 20, %esp
 popl %ebx
 popl %ebp
 ret
Andrew.