Load app images

Support in-place patching of the app image based on boot image
location and app oat location. Only loads for art run test so far
since we do not automatically generate app images for app installs.

N5 maps launch time (~200 runs):
Before: 930ms
After: 878.18ms
After + image class table: 864.57ms

TODO:
Oatdump support.
Store class loaders as class roots in image.

Bug: 22858531

Change-Id: I9cbc645645e62ea2ed1ad8e139e91af7d88514c1

1 files changed, 23 insertions, 10 deletions

diff --git a/test/496-checker-inlining-and-class-loader/src/Main.java b/test/496-checker-inlining-and-class-loader/src/Main.java
index 39c031a6bc..ea6df623a1 100644
--- a/test/496-checker-inlining-and-class-loader/src/Main.java
+++ b/test/496-checker-inlining-and-class-loader/src/Main.java
@@ -16,6 +16,7 @@
 
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
+import java.util.ArrayList;
 import java.util.List;
 
 class MyClassLoader extends ClassLoader {
@@ -30,18 +31,31 @@ class MyClassLoader extends ClassLoader {
     Object pathList = f.get(loader);
 
     // Some magic to get access to the dexField field of pathList.
+    // Need to make a copy of the dex elements since we don't want an app image with pre-resolved
+    // things.
     f = pathList.getClass().getDeclaredField("dexElements");
     f.setAccessible(true);
-    dexElements = (Object[]) f.get(pathList);
-    dexFileField = dexElements[0].getClass().getDeclaredField("dexFile");
-    dexFileField.setAccessible(true);
+    Object[] dexElements = (Object[]) f.get(pathList);
+    f = dexElements[0].getClass().getDeclaredField("dexFile");
+    f.setAccessible(true);
+    for (Object element : dexElements) {
+      Object dexFile = f.get(element);
+      // Make copy.
+      Field fileNameField = dexFile.getClass().getDeclaredField("mFileName");
+      fileNameField.setAccessible(true);
+      dexFiles.add(dexFile.getClass().getDeclaredConstructor(String.class).newInstance(
+        fileNameField.get(dexFile)));
+    }
   }
 
-  Object[] dexElements;
+  ArrayList<Object> dexFiles = new ArrayList<Object>();
   Field dexFileField;
 
   protected Class<?> loadClass(String className, boolean resolve) throws ClassNotFoundException {
-    System.out.println("Request for " + className);
+    // Other classes may also get loaded, ignore those.
+    if (className.equals("LoadedByMyClassLoader") || className.equals("FirstSeenByMyClassLoader")) {
+      System.out.println("Request for " + className);
+    }
 
     // We're only going to handle LoadedByMyClassLoader.
     if (className != "LoadedByMyClassLoader") {
@@ -50,13 +64,12 @@ class MyClassLoader extends ClassLoader {
 
     // Mimic what DexPathList.findClass is doing.
     try {
-      for (Object element : dexElements) {
-        Object dex = dexFileField.get(element);
-        Method method = dex.getClass().getDeclaredMethod(
+      for (Object dexFile : dexFiles) {
+        Method method = dexFile.getClass().getDeclaredMethod(
             "loadClassBinaryName", String.class, ClassLoader.class, List.class);
 
-        if (dex != null) {
-          Class clazz = (Class)method.invoke(dex, className, this, null);
+        if (dexFile != null) {
+          Class clazz = (Class)method.invoke(dexFile, className, this, null);
           if (clazz != null) {
             return clazz;
           }