Allow invalid register references in debug items related to locals.

Art doesn't complain about this, so we shouldn't throw an error when
encountering a dex file with something like this.

baksmali/src/test/java/org/jf/baksmali/LargeLocalTest.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.jf.baksmali;
+
+import org.junit.Test;
+
+/**
+ * Test for a bug related to debug items that refer to a register that's outside the expected range for a method
+ */
+public class LargeLocalTest extends IdenticalRoundtripTest {
+    @Test
+    public void testLargeEndLocal() {
+        runTest("LargeEndLocal");
+    }
+
+    @Test
+    public void testLargeRestartLocal() {
+        runTest("LargeRestartLocal");
+    }
+
+    @Test
+    public void testLargeStartLocal() {
+        runTest("LargeStartLocal");
+    }
+}

baksmali/src/test/resources/LargeLocalTest/LargeEndLocal.smali

@@ -0,0 +1,11 @@
+.class LLargeRestartLocal;
+.super Ljava/lang/Object;
+
+
+# virtual methods
+.method public static main([Ljava/lang/String;)V
+    .registers 2
+
+    .end local p99
+    return-void
+.end method

baksmali/src/test/resources/LargeLocalTest/LargeRestartLocal.smali

@@ -0,0 +1,11 @@
+.class LLargeEndLocal;
+.super Ljava/lang/Object;
+
+
+# virtual methods
+.method public static main([Ljava/lang/String;)V
+    .registers 2
+
+    .restart local p99
+    return-void
+.end method

baksmali/src/test/resources/LargeLocalTest/LargeStartLocal.smali

@@ -0,0 +1,11 @@
+.class LLargeStartLocal;
+.super Ljava/lang/Object;
+
+
+# virtual methods
+.method public static main([Ljava/lang/String;)V
+    .registers 2
+
+    .local p99, "blah":I
+    return-void
+.end method

dexlib2/src/main/java/org/jf/dexlib2/dexbacked/util/DebugInfo.java

@@ -182,7 +182,9 @@ public abstract class DebugInfo implements Iterable<DebugItem> {
                                 String type = dexFile.getOptionalType(reader.readSmallUleb128() - 1);
                                 ImmutableStartLocal startLocal =
                                         new ImmutableStartLocal(codeAddress, register, name, type, null);
-                                locals[register] = startLocal;
+                                if (register >= 0 && register < locals.length) {
+                                    locals[register] = startLocal;
+                                }
                                 return startLocal;
                             }
                             case DebugItemType.START_LOCAL_EXTENDED: {
@@ -192,13 +194,23 @@ public abstract class DebugInfo implements Iterable<DebugItem> {
                                 String signature = dexFile.getOptionalString(reader.readSmallUleb128() - 1);
                                 ImmutableStartLocal startLocal =
                                         new ImmutableStartLocal(codeAddress, register, name, type, signature);
-                                locals[register] = startLocal;
+                                if (register >= 0 && register < locals.length) {
+                                    locals[register] = startLocal;
+                                }
                                 return startLocal;
                             }
                             case DebugItemType.END_LOCAL: {
                                 int register = reader.readSmallUleb128();
-                                LocalInfo localInfo = locals[register];
+
                                 boolean replaceLocalInTable = true;
+                                LocalInfo localInfo;
+                                if (register >= 0 && register < locals.length) {
+                                    localInfo = locals[register];
+                                } else {
+                                    localInfo = EMPTY_LOCAL_INFO;
+                                    replaceLocalInTable = false;
+                                }
+
                                 if (localInfo instanceof EndLocal) {
                                     localInfo = EMPTY_LOCAL_INFO;
                                     // don't replace the local info in locals. The new EndLocal won't have any info at all,
@@ -216,11 +228,18 @@ public abstract class DebugInfo implements Iterable<DebugItem> {
                             }
                             case DebugItemType.RESTART_LOCAL: {
                                 int register = reader.readSmallUleb128();
-                                LocalInfo localInfo = locals[register];
+                                LocalInfo localInfo;
+                                if (register >= 0 && register < locals.length) {
+                                    localInfo = locals[register];
+                                } else {
+                                    localInfo = EMPTY_LOCAL_INFO;
+                                }
                                 ImmutableRestartLocal restartLocal =
                                         new ImmutableRestartLocal(codeAddress, register, localInfo.getName(),
                                                 localInfo.getType(), localInfo.getSignature());
-                                locals[register] = restartLocal;
+                                if (register >= 0 && register < locals.length) {
+                                    locals[register] = restartLocal;
+                                }
                                 return restartLocal;
                             }
                             case DebugItemType.PROLOGUE_END: {