Some thinking about exceptions

src/main/java/info/sigterm/deob/attributes/Attributes.java

@@ -47,6 +47,11 @@ public class Attributes
 		load();
 	}
 	
+	public Method getMethod()
+	{
+		return method;
+	}
+
 	public Attribute findType(AttributeType type)
 	{
 		for (Attribute a : attributes)

src/main/java/info/sigterm/deob/attributes/Code.java

@@ -39,6 +39,11 @@ public class Code extends Attribute
 		return maxLocals;
 	}
 	
+	public Exceptions getExceptions()
+	{
+		return exceptions;
+	}
+	
 	public Instructions getInstructions()
 	{
 		return instructions;

src/main/java/info/sigterm/deob/attributes/code/Exception.java

@@ -1,9 +1,11 @@
 package info.sigterm.deob.attributes.code;
 
+import info.sigterm.deob.ConstantPool;
+
 import java.io.DataInputStream;
 import java.io.IOException;
 
-class Exception
+public class Exception
 {
 	private Exceptions exceptions;
 
@@ -23,4 +25,24 @@ class Exception
 		handlerPc = is.readUnsignedShort();
 		catchType = is.readUnsignedShort();
 	}
+	
+	public Exceptions getExceptions()
+	{
+		return exceptions;
+	}
+	
+	public int getStartPc()
+	{
+		return startPc;
+	}
+	
+	public int getEndPc()
+	{
+		return endPc;
+	}
+	
+	public int getHandlerPc()
+	{
+		return handlerPc;
+	}
 }

src/main/java/info/sigterm/deob/attributes/code/Exceptions.java

@@ -1,9 +1,12 @@
 package info.sigterm.deob.attributes.code;
 
 import info.sigterm.deob.attributes.Code;
+import info.sigterm.deob.execution.ObjectInstance;
 
 import java.io.DataInputStream;
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
 
 public class Exceptions
 {
@@ -27,4 +30,20 @@ public class Exceptions
 	{
 		return code;
 	}
+	
+	public Collection<Exception> getHandlersForPc(int pc)
+	{
+		ArrayList<Exception> matches = new ArrayList<Exception>();
+
+		for (Exception e : exceptions)
+		{
+			if (pc >= e.getStartPc() && pc < e.getEndPc())
+			{
+				/* possible match */
+				matches.add(e);
+			}
+		}
+		
+		return matches;
+	}
 }

src/main/java/info/sigterm/deob/attributes/code/instructions/AThrow.java

@@ -19,6 +19,6 @@ public class AThrow extends Instruction
 	public void execute(Frame e)
 	{
 		ObjectInstance exception = (ObjectInstance) e.getStack().pop();
-		e.getPath().throwException(exception);
+		e.getPath().throwException(this, exception);
 	}
 }

src/main/java/info/sigterm/deob/execution/Frame.java

@@ -1,7 +1,10 @@
 package info.sigterm.deob.execution;
 
+import java.util.Collection;
+
 import info.sigterm.deob.Method;
 import info.sigterm.deob.attributes.Code;
+import info.sigterm.deob.attributes.code.Exception;
 import info.sigterm.deob.attributes.code.Instruction;
 import info.sigterm.deob.attributes.code.Instructions;
 
@@ -40,6 +43,11 @@ public class Frame
 		return path;
 	}
 	
+	public Method getMethod()
+	{
+		return method;
+	}
+
 	public Stack getStack()
 	{
 		return stack;
@@ -102,4 +110,14 @@ public class Frame
 		assert offset != 0;
 		pc += offset;
 	}
+	
+	public void jumpAbsolute(int pc)
+	{
+		this.pc = pc;
+	}
+	
+	public Collection<Exception> getExceptionHandlers()
+	{
+		return method.getCode().getExceptions().getHandlersForPc(this.pc);
+	}
 }

src/main/java/info/sigterm/deob/execution/Path.java

@@ -2,9 +2,11 @@ package info.sigterm.deob.execution;
 
 import info.sigterm.deob.ClassFile;
 import info.sigterm.deob.Method;
+import info.sigterm.deob.attributes.code.Exception;
 import info.sigterm.deob.attributes.code.Instruction;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashMap;
 
 public class Path
@@ -112,9 +114,29 @@ public class Path
 		currentFrame.executing = false;
 	}
 	
-	public void throwException(ObjectInstance exception)
+	public void throwException(Instruction ins, ObjectInstance exception)
 	{
-		System.out.println("XXX throw " + exception);
+		ArrayList<Exception> exceptions = new ArrayList<Exception>();
-		//XXX
+		
+		/* collect all existing exception handlers */
+		for (Frame f : frames)
+		{
+			Collection<Exception> handlers = f.getExceptionHandlers();
+			exceptions.addAll(handlers);
+		}
+		
+		for (Exception handler : exceptions)
+		{
+			/* jump to handler */
+			Method handlerMethod = handler.getExceptions().getCode().getAttributes().getMethod();
+			
+			Path other = this.dup();
+			/* walk up the frames until we find the one which holds the exception handler */ 
+			while (handlerMethod != other.getCurrentFrame().getMethod())
+				other.returnFrame();
+			
+			/* handler pc is absolute from the beginning instruction */
+			other.getCurrentFrame().jumpAbsolute(handler.getHandlerPc());
+		}
 	}
 }