Description Darren Price 2005-07-20 20:14:31 EDT

This problem may only occur when Aspect/J tries to do a weaveAroundInline() on 
an instruction list that includes a Select.  Our usage of Aspect/J only rarely 
causes it to use weaveAroundInline(), so I don't have any other cases for 
comparison.

In ShadowRange:extractInstructionsInto(), my instruction list includes a 
Select.  Each of the targets of the Select has a list of targetters that 
includes what appears to be a Select from some other instantiation of the 
instruction list, in addition to the local Select.  The updateTarget() call on 
the bogus Select targetter causes the ClassGenException (stack trace attached 
below).

My clumsy band-aid (also attached below) is to clean the bad state from the 
Select targets at the top of extractInstructionsInto().  However, I presume 
that the real fix needs to be done at the point the bad state was introduced 
into the instruction list.

I noticed that a possibly similar problem was reported awhile back, but 
apparently not in a reliably reproducible way.  From browsing through the top 
of the CVS tree, it appears that the weaver/bcel directory hasn't changed 
drastically since 1.2, so I assume that this problem may still be lurking 
there.

Here's the stack trace:

AspectJInstrumenter:weaveClass,org.apache.bcel.generic.ClassGenException: Not
targeting   36: aload_0[42](1)
AspectJInstrumenter:weaveClass,	at
org.apache.bcel.generic.Select.updateTarget(Select.java:213)
AspectJInstrumenter:weaveClass,	at
org.aspectj.weaver.bcel.ShadowRange.extractInstructionsInto
(ShadowRange.java:138)
AspectJInstrumenter:weaveClass,	at
org.aspectj.weaver.bcel.BcelShadow.extractMethod(BcelShadow.java:2002)
AspectJInstrumenter:weaveClass,	at
org.aspectj.weaver.bcel.BcelShadow.weaveAroundInline(BcelShadow.java:1436)
AspectJInstrumenter:weaveClass,	at
org.aspectj.weaver.bcel.BcelAdvice.implementOn(BcelAdvice.java:151)
AspectJInstrumenter:weaveClass,	at
org.aspectj.weaver.Shadow.implementMungers(Shadow.java:353)
AspectJInstrumenter:weaveClass,	at
org.aspectj.weaver.Shadow.implement(Shadow.java:325)
AspectJInstrumenter:weaveClass,	at
org.aspectj.weaver.bcel.BcelClassWeaver.implement(BcelClassWeaver.java:1161)
AspectJInstrumenter:weaveClass,	at
org.aspectj.weaver.bcel.BcelClassWeaver.weave(BcelClassWeaver.java:367)
AspectJInstrumenter:weaveClass,	at
org.aspectj.weaver.bcel.BcelClassWeaver.weave(BcelClassWeaver.java:80)
AspectJInstrumenter:weaveClass,	at
org.aspectj.weaver.bcel.BcelWeaver.weave(BcelWeaver.java:724)
AspectJInstrumenter:weaveClass,	at
org.aspectj.weaver.bcel.BcelWeaver.weaveWithoutDump(BcelWeaver.java:689)
AspectJInstrumenter:weaveClass,	at
org.aspectj.weaver.bcel.BcelWeaver.weaveAndNotify(BcelWeaver.java:615)
AspectJInstrumenter:weaveClass,	at
org.aspectj.weaver.bcel.BcelWeaver.weave(BcelWeaver.java:563)
AspectJInstrumenter:weaveClass,	at
com.acsera.javaagent.AspectJWeavingAdaptor.getWovenBytes
(AspectJWeavingAdaptor.java:244)
AspectJInstrumenter:weaveClass,	at
com.acsera.javaagent.AspectJWeavingAdaptor.weaveClass
(AspectJWeavingAdaptor.java:210)

And here's the patch:

void extractInstructionsInto(LazyMethodGen freshMethod, IntMap remap, boolean 
addReturn) {
	// XXX Darren
		// Find all the Select instructions in this list, and all of 
their targets.
		// Run through the targets and remove any Select targeters 
that aren't from this list.

		java.util.Set selectSet = new java.util.HashSet();
		java.util.Set targetSet = new java.util.HashSet();
		for ( InstructionHandle ih = start.getNext(); ih != end; ih = 
ih.getNext() ) {
			Instruction ii = ih.getInstruction();
			if ( ii instanceof Select ) {
				Select si = (Select) ii;
				selectSet.add( si );
				targetSet.add( si.getTarget() );
				InstructionHandle[] targets = si.getTargets();
				for ( int k = 0; k < targets.length; k++ ) {
					targetSet.add( targets[ k ] );
				}
			}
		}
		java.util.Iterator it = targetSet.iterator();
		while ( it.hasNext() ) {
			InstructionHandle ih = (InstructionHandle) it.next();
			InstructionTargeter[] its = ih.getTargeters();
			if ( its == null ) {
				continue;	// XXX internal consistency 
error?
			}
			for ( int k = 0; k < its.length; k++ ) {
				if ( its[k] instanceof Select ) {
					Select si = (Select) its[k];
					if ( ! selectSet.contains( si ) ) {
						// XXX System.out.println
( "ShadowRange:extractInstructionsInto: bogus Select " + si.toString() + " " + 
si.hashCode() );
						ih.removeTargeter( si );
					}
				}
			}
		}
		// XXX Darren