Refactors in preparation for exceptions support.

This adds in some pieces that will be needed for exceptions in the more
general case, then switches the existing next/last/redo exceptions over
to using the new approach. (Note, they need integrating so CONTROL,
which may run on the stack top and resume, will work out.)

src/org/perl6/nqp/runtime/CallFrame.java

@@ -81,6 +81,11 @@ public class CallFrame {
     public static final int RET_NUM = 2;
     public static final int RET_STR = 3;
 
+    /**
+     * The current handler we're in, in this block. 0 if none.
+     */
+    public long curHandler = 0;
+
     /**
      * Current working copy of the named arguments data.
      */

src/org/perl6/nqp/runtime/CodeRef.java

@@ -27,10 +27,11 @@ public class CodeRef extends SixModelObject {
     public CodeRef(CompilationUnit compUnit, int idx, String name, String uniqueId,
             String[] oLexicalNames, String[] iLexicalNames,
             String[] nLexicalNames, String[] sLexicalNames,
-            short oMaxArgs, short iMaxArgs, short nMaxArgs, short sMaxArgs) {
+            short oMaxArgs, short iMaxArgs, short nMaxArgs, short sMaxArgs,
+            long[][] handlers) {
         staticInfo = new StaticCodeInfo(compUnit, idx, name,uniqueId,
                 oLexicalNames, iLexicalNames, nLexicalNames, sLexicalNames,
-                oMaxArgs, iMaxArgs, nMaxArgs, sMaxArgs);
+                oMaxArgs, iMaxArgs, nMaxArgs, sMaxArgs, handlers);
     }
 
     /**

src/org/perl6/nqp/runtime/ExceptionHandling.java

@@ -0,0 +1,57 @@
+package org.perl6.nqp.runtime;
+
+import org.perl6.nqp.sixmodel.*;
+
+public class ExceptionHandling {
+	/* Exception handler categories. */
+	public static final int EX_CAT_CATCH = 1;
+	public static final int EX_CAT_CONTROL = 2;
+	public static final int EX_CAT_NEXT = 4;
+	public static final int EX_CAT_REDO = 8;
+	public static final int EX_CAT_LAST = 16;
+
+	/* Exception handler kinds. */
+	public static final int EX_UNWIND_SIMPLE = 0;
+	public static final int EX_UNWIND_OBJECT = 1;
+	public static final int EX_BLOCK = 2;
+
+	/* Finds and executes a handler, using dynamic scope to find it. */
+	public static SixModelObject handlerDynamic(ThreadContext tc, long category) {
+		CallFrame f = tc.curFrame;
+		while (f != null) {
+			if (f.curHandler != 0) {
+				long tryHandler = f.curHandler;				
+				long[][] handlers = f.codeRef.staticInfo.handlers;
+				while (tryHandler != 0) {
+					for (int i = 0; i < handlers.length; i++) {
+						if (handlers[i][0] == tryHandler) {
+							// Found an active one, but is it the right category?
+							if ((handlers[i][2] & category) != 0)
+								return invokeHandler(tc, handlers[i], category);
+
+							// If not, try outer one.
+							tryHandler = handlers[i][1];
+							break;
+						}
+					}
+				}
+			}
+			f = f.caller;
+		}
+		return panic(tc, category);
+	}
+
+	/* Invokes the handler. */
+	private static SixModelObject invokeHandler(ThreadContext tc, long[] handlerInfo, long category) {
+		// TODO: Should not always just blindly go unwinding, may need an
+		// exception object or to run it in the current dynamic context.
+		tc.unwinder.unwindTarget = handlerInfo[0];
+		tc.unwinder.category = category;
+		throw tc.unwinder;
+	}
+
+	/* Unahndled exception. */
+	private static SixModelObject panic(ThreadContext tc, long category) {
+		throw new RuntimeException("Unhandled exception; category = " + category);
+	}
+}

src/org/perl6/nqp/runtime/Ops.java

@@ -2206,6 +2206,9 @@ public static SixModelObject die(SixModelObject msg, ThreadContext tc) {
     	// TODO Implement exceptions properly.
     	throw new RuntimeException(msg.get_str(tc));
     }
+    public static SixModelObject throwcatdyn(long category, ThreadContext tc) {
+    	return ExceptionHandling.handlerDynamic(tc, category);
+    }
 
     /* HLL configuration and compiler related options. */
     public static SixModelObject sethllconfig(String language, SixModelObject configHash, ThreadContext tc) {

src/org/perl6/nqp/runtime/StaticCodeInfo.java

@@ -56,6 +56,11 @@ public class StaticCodeInfo {
     public String[] nLexicalNames;
     public String[] sLexicalNames;
 
+    /**
+     * Map of handlers.
+     */
+    public long[][] handlers;
+
     /**
      * Lexical name maps (produced lazily on first use). Note they are only
      * used when we do lexical lookup by name.
@@ -115,7 +120,8 @@ public Integer sTryGetLexicalIdx(String name) {
     public StaticCodeInfo(CompilationUnit compUnit, int idx, String name, String uniqueId,
             String[] oLexicalNames, String[] iLexicalNames,
             String[] nLexicalNames, String[] sLexicalNames,
-            short oMaxArgs, short iMaxArgs, short nMaxArgs, short sMaxArgs) {
+            short oMaxArgs, short iMaxArgs, short nMaxArgs, short sMaxArgs,
+            long[][] handlers) {
         this.compUnit = compUnit;
         this.idx = idx;
         this.name = name;
@@ -128,6 +134,7 @@ public StaticCodeInfo(CompilationUnit compUnit, int idx, String name, String uni
         this.iMaxArgs = iMaxArgs;
         this.nMaxArgs = nMaxArgs;
         this.sMaxArgs = sMaxArgs;
+        this.handlers = handlers;
         if (oLexicalNames != null)
         	this.oLexStatic = new SixModelObject[oLexicalNames.length];
     }

src/org/perl6/nqp/runtime/ThreadContext.java

@@ -42,6 +42,11 @@ public class ThreadContext {
     public static final int NATIVE_STR = 3;
     public static final int NATIVE_JVM_OBJ = 4;
 
+    /**
+     * The current unwind exception.
+     */
+    public UnwindException unwinder;
+
     /**
      * The current lexotic we're throwing.
      */
@@ -55,6 +60,7 @@ public class ThreadContext {
     public ThreadContext(GlobalContext gc) {
         this.gc = gc;
         this.theLexotic = new LexoticException();
+        this.unwinder = new UnwindException();
         if (gc.CallCapture != null) {
         	savedCC = (CallCaptureInstance)gc.CallCapture.st.REPR.allocate(this, gc.CallCapture.st);
         	savedCC.initialize(this);

src/org/perl6/nqp/runtime/UnwindException.java

@@ -0,0 +1,7 @@
+package org.perl6.nqp.runtime;
+
+public class UnwindException extends RuntimeException {
+	private static final long serialVersionUID = -2452898396745530180L;
+	public long unwindTarget;
+	public long category;
+}

src/org/perl6/nqp/sixmodel/KnowHOWMethods.java

@@ -235,19 +235,20 @@ public void InvokeCode(ThreadContext tc, int idx) {
     public CodeRef[] getCodeRefs() {
         CodeRef[] refs = new CodeRef[12];
         String[] snull = null;
+        long[][] hnull = new long[0][];
         short zero = 0;
-        refs[0] = new CodeRef(this, 0, "new_type", "new_type", snull, snull, snull, snull, zero, zero, zero, zero);
-        refs[1] = new CodeRef(this, 1, "add_method", "add_method", snull, snull, snull, snull, zero, zero, zero, zero);
-        refs[2] = new CodeRef(this, 2, "add_attribute", "add_attribute", snull, snull, snull, snull, zero, zero, zero, zero);
-        refs[3] = new CodeRef(this, 3, "compose", "compose", snull, snull, snull, snull, zero, zero, zero, zero);
-        refs[4] = new CodeRef(this, 4, "attributes", "attributes", snull, snull, snull, snull, zero, zero, zero, zero);
-        refs[5] = new CodeRef(this, 5, "methods", "methods", snull, snull, snull, snull, zero, zero, zero, zero);
-        refs[6] = new CodeRef(this, 6, "name", "name", snull, snull, snull, snull, zero, zero, zero, zero);
-        refs[7] = new CodeRef(this, 7, "new", "attr_new", snull, snull, snull, snull, zero, zero, zero, zero);
-        refs[8] = new CodeRef(this, 8, "compose", "attr_compose", snull, snull, snull, snull, zero, zero, zero, zero);
-        refs[9] = new CodeRef(this, 9, "name", "attr_name", snull, snull, snull, snull, zero, zero, zero, zero);
-        refs[10] = new CodeRef(this, 10, "type", "attr_type", snull, snull, snull, snull, zero, zero, zero, zero);
-        refs[11] = new CodeRef(this, 11, "box_target", "attr_box_target", snull, snull, snull, snull, zero, zero, zero, zero);
+        refs[0] = new CodeRef(this, 0, "new_type", "new_type", snull, snull, snull, snull, zero, zero, zero, zero, hnull);
+        refs[1] = new CodeRef(this, 1, "add_method", "add_method", snull, snull, snull, snull, zero, zero, zero, zero, hnull);
+        refs[2] = new CodeRef(this, 2, "add_attribute", "add_attribute", snull, snull, snull, snull, zero, zero, zero, zero, hnull);
+        refs[3] = new CodeRef(this, 3, "compose", "compose", snull, snull, snull, snull, zero, zero, zero, zero, hnull);
+        refs[4] = new CodeRef(this, 4, "attributes", "attributes", snull, snull, snull, snull, zero, zero, zero, zero, hnull);
+        refs[5] = new CodeRef(this, 5, "methods", "methods", snull, snull, snull, snull, zero, zero, zero, zero, hnull);
+        refs[6] = new CodeRef(this, 6, "name", "name", snull, snull, snull, snull, zero, zero, zero, zero, hnull);
+        refs[7] = new CodeRef(this, 7, "new", "attr_new", snull, snull, snull, snull, zero, zero, zero, zero, hnull);
+        refs[8] = new CodeRef(this, 8, "compose", "attr_compose", snull, snull, snull, snull, zero, zero, zero, zero, hnull);
+        refs[9] = new CodeRef(this, 9, "name", "attr_name", snull, snull, snull, snull, zero, zero, zero, zero, hnull);
+        refs[10] = new CodeRef(this, 10, "type", "attr_type", snull, snull, snull, snull, zero, zero, zero, zero, hnull);
+        refs[11] = new CodeRef(this, 11, "box_target", "attr_box_target", snull, snull, snull, snull, zero, zero, zero, zero, hnull);
         return refs;
     }