From 4273457c9e57f95390d591bedb0eebd15debfc6f Mon Sep 17 00:00:00 2001
From: Eric Holk <eholk@google.com>
Date: Mon, 17 Dec 2018 15:46:18 -0800
Subject: [view compiler] Add XML to DEX compilation

Test: atest
Bug: 111895153
Change-Id: I91c01ff4474e080c87b902ae963b5d655346f859
---
 startop/view_compiler/Android.bp                   |   1 +
 startop/view_compiler/dex_builder_test/Android.bp  |  18 +-
 .../view_compiler/dex_builder_test/AndroidTest.xml |   1 +
 .../dex_builder_test/res/layout/layout1.xml        |  17 ++
 .../android/startop/test/LayoutCompilerTest.java   |  46 +++++
 startop/view_compiler/dex_layout_compiler.cc       | 226 +++++++++++++++++++++
 startop/view_compiler/dex_layout_compiler.h        | 118 +++++++++++
 startop/view_compiler/java_lang_builder.cc         |   2 +-
 startop/view_compiler/java_lang_builder.h          |   2 +-
 startop/view_compiler/main.cc                      |  74 +++++--
 10 files changed, 479 insertions(+), 26 deletions(-)
 create mode 100644 startop/view_compiler/dex_builder_test/res/layout/layout1.xml
 create mode 100644 startop/view_compiler/dex_builder_test/src/android/startop/test/LayoutCompilerTest.java
 create mode 100644 startop/view_compiler/dex_layout_compiler.cc
 create mode 100644 startop/view_compiler/dex_layout_compiler.h

diff --git a/startop/view_compiler/Android.bp b/startop/view_compiler/Android.bp
index 91cec554d7cd..82056e9a33fe 100644
--- a/startop/view_compiler/Android.bp
+++ b/startop/view_compiler/Android.bp
@@ -34,6 +34,7 @@ cc_library_host_static {
     defaults: ["viewcompiler_defaults"],
     srcs: [
         "dex_builder.cc",
+        "dex_layout_compiler.cc",
         "java_lang_builder.cc",
         "tinyxml_layout_parser.cc",
         "util.cc",
diff --git a/startop/view_compiler/dex_builder_test/Android.bp b/startop/view_compiler/dex_builder_test/Android.bp
index 4449ea0f707e..d4f38ed148c9 100644
--- a/startop/view_compiler/dex_builder_test/Android.bp
+++ b/startop/view_compiler/dex_builder_test/Android.bp
@@ -14,16 +14,30 @@
 // limitations under the License.
 //
 
+genrule {
+    name: "generate_compiled_layout",
+    tools: [":viewcompiler"],
+    cmd: "$(location :viewcompiler) $(in) --dex --out $(out) --package android.startop.test",
+    srcs: ["res/layout/layout1.xml"],
+    out: [
+        "layout1.dex",
+    ],
+}
+
 android_test {
     name: "dex-builder-test",
-    srcs: ["src/android/startop/test/DexBuilderTest.java"],
+    srcs: [
+        "src/android/startop/test/DexBuilderTest.java",
+        "src/android/startop/test/LayoutCompilerTest.java",
+    ],
     sdk_version: "current",
-    data: [":generate_dex_testcases"],
+    data: [":generate_dex_testcases", ":generate_compiled_layout"],
     static_libs: [
         "android-support-test",
         "guava",
     ],
     manifest: "AndroidManifest.xml",
+    resource_dirs: ["res"],
     test_config: "AndroidTest.xml",
     test_suites: ["general-tests"],
 }
diff --git a/startop/view_compiler/dex_builder_test/AndroidTest.xml b/startop/view_compiler/dex_builder_test/AndroidTest.xml
index 6f90cf3b81a7..68d8fdc444d8 100644
--- a/startop/view_compiler/dex_builder_test/AndroidTest.xml
+++ b/startop/view_compiler/dex_builder_test/AndroidTest.xml
@@ -25,6 +25,7 @@
         <option name="cleanup" value="true" />
         <option name="push" value="trivial.dex->/data/local/tmp/dex-builder-test/trivial.dex" />
         <option name="push" value="simple.dex->/data/local/tmp/dex-builder-test/simple.dex" />
+        <option name="push" value="layout1.dex->/data/local/tmp/dex-builder-test/layout1.dex" />
     </target_preparer>
 
     <test class="com.android.tradefed.testtype.AndroidJUnitTest" >
diff --git a/startop/view_compiler/dex_builder_test/res/layout/layout1.xml b/startop/view_compiler/dex_builder_test/res/layout/layout1.xml
new file mode 100644
index 000000000000..0f9375c6ebce
--- /dev/null
+++ b/startop/view_compiler/dex_builder_test/res/layout/layout1.xml
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+   android:layout_width="match_parent"
+   android:layout_height="match_parent"
+   android:paddingLeft="16dp"
+   android:paddingRight="16dp"
+   android:orientation="vertical"
+   android:gravity="center">
+
+    <Button
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"/>
+    <Button
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"/>
+
+ </LinearLayout>
diff --git a/startop/view_compiler/dex_builder_test/src/android/startop/test/LayoutCompilerTest.java b/startop/view_compiler/dex_builder_test/src/android/startop/test/LayoutCompilerTest.java
new file mode 100644
index 000000000000..ce3ce8328559
--- /dev/null
+++ b/startop/view_compiler/dex_builder_test/src/android/startop/test/LayoutCompilerTest.java
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License
+ * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ * or implied. See the License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package android.startop.test;
+
+import android.content.Context;
+import android.support.test.InstrumentationRegistry;
+import android.view.View;
+import com.google.common.io.ByteStreams;
+import dalvik.system.InMemoryDexClassLoader;
+import dalvik.system.PathClassLoader;
+import java.io.InputStream;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.nio.ByteBuffer;
+import org.junit.Assert;
+import org.junit.Test;
+
+// Adding tests here requires changes in several other places. See README.md in
+// the view_compiler directory for more information.
+public class LayoutCompilerTest {
+    static ClassLoader loadDexFile(String filename) throws Exception {
+        return new PathClassLoader("/data/local/tmp/dex-builder-test/" + filename,
+                ClassLoader.getSystemClassLoader());
+    }
+
+    @Test
+    public void loadAndInflaterLayout1() throws Exception {
+        ClassLoader dex_file = loadDexFile("layout1.dex");
+        Class compiled_view = dex_file.loadClass("android.startop.test.CompiledView");
+        Method layout1 = compiled_view.getMethod("layout1", Context.class, int.class);
+        Context context = InstrumentationRegistry.getTargetContext();
+        layout1.invoke(null, context, R.layout.layout1);
+    }
+}
diff --git a/startop/view_compiler/dex_layout_compiler.cc b/startop/view_compiler/dex_layout_compiler.cc
new file mode 100644
index 000000000000..c68793d10399
--- /dev/null
+++ b/startop/view_compiler/dex_layout_compiler.cc
@@ -0,0 +1,226 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "dex_layout_compiler.h"
+#include "layout_validation.h"
+
+#include "android-base/stringprintf.h"
+
+namespace startop {
+
+using android::base::StringPrintf;
+
+void LayoutValidationVisitor::VisitStartTag(const std::u16string& name) {
+  if (0 == name.compare(u"merge")) {
+    message_ = "Merge tags are not supported";
+    can_compile_ = false;
+  }
+  if (0 == name.compare(u"include")) {
+    message_ = "Include tags are not supported";
+    can_compile_ = false;
+  }
+  if (0 == name.compare(u"view")) {
+    message_ = "View tags are not supported";
+    can_compile_ = false;
+  }
+  if (0 == name.compare(u"fragment")) {
+    message_ = "Fragment tags are not supported";
+    can_compile_ = false;
+  }
+}
+
+DexViewBuilder::DexViewBuilder(dex::MethodBuilder* method)
+    : method_{method},
+      context_{dex::Value::Parameter(0)},
+      resid_{dex::Value::Parameter(1)},
+      inflater_{method->MakeRegister()},
+      xml_{method->MakeRegister()},
+      attrs_{method->MakeRegister()},
+      classname_tmp_{method->MakeRegister()},
+      xml_next_{method->dex_file()->GetOrDeclareMethod(
+          dex::TypeDescriptor::FromClassname("android.content.res.XmlResourceParser"), "next",
+          dex::Prototype{dex::TypeDescriptor::Int()})},
+      try_create_view_{method->dex_file()->GetOrDeclareMethod(
+          dex::TypeDescriptor::FromClassname("android.view.LayoutInflater"), "tryCreateView",
+          dex::Prototype{dex::TypeDescriptor::FromClassname("android.view.View"),
+                         dex::TypeDescriptor::FromClassname("android.view.View"),
+                         dex::TypeDescriptor::FromClassname("java.lang.String"),
+                         dex::TypeDescriptor::FromClassname("android.content.Context"),
+                         dex::TypeDescriptor::FromClassname("android.util.AttributeSet")})},
+      generate_layout_params_{method->dex_file()->GetOrDeclareMethod(
+          dex::TypeDescriptor::FromClassname("android.view.ViewGroup"), "generateLayoutParams",
+          dex::Prototype{dex::TypeDescriptor::FromClassname("android.view.ViewGroup$LayoutParams"),
+                         dex::TypeDescriptor::FromClassname("android.util.AttributeSet")})},
+      add_view_{method->dex_file()->GetOrDeclareMethod(
+          dex::TypeDescriptor::FromClassname("android.view.ViewGroup"), "addView",
+          dex::Prototype{
+              dex::TypeDescriptor::Void(),
+              dex::TypeDescriptor::FromClassname("android.view.View"),
+              dex::TypeDescriptor::FromClassname("android.view.ViewGroup$LayoutParams")})},
+      // The register stack starts with one register, which will be null for the root view.
+      register_stack_{{method->MakeRegister()}} {}
+
+void DexViewBuilder::Start() {
+  dex::DexBuilder* const dex = method_->dex_file();
+
+  // LayoutInflater inflater = LayoutInflater.from(context);
+  auto layout_inflater_from = dex->GetOrDeclareMethod(
+      dex::TypeDescriptor::FromClassname("android.view.LayoutInflater"),
+      "from",
+      dex::Prototype{dex::TypeDescriptor::FromClassname("android.view.LayoutInflater"),
+                     dex::TypeDescriptor::FromClassname("android.content.Context")});
+  method_->AddInstruction(
+      dex::Instruction::InvokeStaticObject(layout_inflater_from.id, /*dest=*/inflater_, context_));
+
+  // Resources res = context.getResources();
+  auto context_type = dex::TypeDescriptor::FromClassname("android.content.Context");
+  auto resources_type = dex::TypeDescriptor::FromClassname("android.content.res.Resources");
+  auto get_resources =
+      dex->GetOrDeclareMethod(context_type, "getResources", dex::Prototype{resources_type});
+  method_->AddInstruction(dex::Instruction::InvokeVirtualObject(get_resources.id, xml_, context_));
+
+  // XmlResourceParser xml = res.getLayout(resid);
+  auto xml_resource_parser_type =
+      dex::TypeDescriptor::FromClassname("android.content.res.XmlResourceParser");
+  auto get_layout =
+      dex->GetOrDeclareMethod(resources_type,
+                              "getLayout",
+                              dex::Prototype{xml_resource_parser_type, dex::TypeDescriptor::Int()});
+  method_->AddInstruction(dex::Instruction::InvokeVirtualObject(get_layout.id, xml_, xml_, resid_));
+
+  // AttributeSet attrs = Xml.asAttributeSet(xml);
+  auto as_attribute_set = dex->GetOrDeclareMethod(
+      dex::TypeDescriptor::FromClassname("android.util.Xml"),
+      "asAttributeSet",
+      dex::Prototype{dex::TypeDescriptor::FromClassname("android.util.AttributeSet"),
+                     dex::TypeDescriptor::FromClassname("org.xmlpull.v1.XmlPullParser")});
+  method_->AddInstruction(dex::Instruction::InvokeStaticObject(as_attribute_set.id, attrs_, xml_));
+
+  // xml.next(); // start document
+  method_->AddInstruction(dex::Instruction::InvokeInterface(xml_next_.id, {}, xml_));
+}
+
+void DexViewBuilder::Finish() {}
+
+namespace {
+std::string ResolveName(const std::string& name) {
+  if (name == "View") return "android.view.View";
+  if (name == "ViewGroup") return "android.view.ViewGroup";
+  if (name.find(".") == std::string::npos) {
+    return StringPrintf("android.widget.%s", name.c_str());
+  }
+  return name;
+}
+}  // namespace
+
+void DexViewBuilder::StartView(const std::string& name, bool is_viewgroup) {
+  bool const is_root_view = view_stack_.empty();
+
+  // xml.next(); // start tag
+  method_->AddInstruction(dex::Instruction::InvokeInterface(xml_next_.id, {}, xml_));
+
+  dex::Value view = AcquireRegister();
+  // try to create the view using the factories
+  method_->BuildConstString(classname_tmp_,
+                            name);  // TODO: the need to fully qualify the classname
+  if (is_root_view) {
+    dex::Value null = AcquireRegister();
+    method_->BuildConst4(null, 0);
+    method_->AddInstruction(dex::Instruction::InvokeVirtualObject(
+        try_create_view_.id, view, inflater_, null, classname_tmp_, context_, attrs_));
+    ReleaseRegister();
+  } else {
+    method_->AddInstruction(dex::Instruction::InvokeVirtualObject(
+        try_create_view_.id, view, inflater_, GetCurrentView(), classname_tmp_, context_, attrs_));
+  }
+  auto label = method_->MakeLabel();
+  // branch if not null
+  method_->AddInstruction(
+      dex::Instruction::OpWithArgs(dex::Instruction::Op::kBranchNEqz, /*dest=*/{}, view, label));
+
+  // If null, create the class directly.
+  method_->BuildNew(view,
+                    dex::TypeDescriptor::FromClassname(ResolveName(name)),
+                    dex::Prototype{dex::TypeDescriptor::Void(),
+                                   dex::TypeDescriptor::FromClassname("android.content.Context"),
+                                   dex::TypeDescriptor::FromClassname("android.util.AttributeSet")},
+                    context_,
+                    attrs_);
+
+  method_->AddInstruction(
+      dex::Instruction::OpWithArgs(dex::Instruction::Op::kBindLabel, /*dest=*/{}, label));
+
+  if (is_viewgroup) {
+    // Cast to a ViewGroup so we can add children later.
+    const ir::Type* view_group_def = method_->dex_file()->GetOrAddType(
+        dex::TypeDescriptor::FromClassname("android.view.ViewGroup").descriptor());
+    method_->AddInstruction(dex::Instruction::Cast(view, dex::Value::Type(view_group_def->orig_index)));
+  }
+
+  if (!is_root_view) {
+    // layout_params = parent.generateLayoutParams(attrs);
+    dex::Value layout_params{AcquireRegister()};
+    method_->AddInstruction(dex::Instruction::InvokeVirtualObject(
+        generate_layout_params_.id, layout_params, GetCurrentView(), attrs_));
+    view_stack_.push_back({view, layout_params});
+  } else {
+    view_stack_.push_back({view, {}});
+  }
+}
+
+void DexViewBuilder::FinishView() {
+  if (view_stack_.size() == 1) {
+    method_->BuildReturn(GetCurrentView(), /*is_object=*/true);
+  } else {
+    // parent.add(view, layout_params)
+    method_->AddInstruction(dex::Instruction::InvokeVirtual(
+        add_view_.id, /*dest=*/{}, GetParentView(), GetCurrentView(), GetCurrentLayoutParams()));
+    // xml.next(); // end tag
+    method_->AddInstruction(dex::Instruction::InvokeInterface(xml_next_.id, {}, xml_));
+  }
+  PopViewStack();
+}
+
+dex::Value DexViewBuilder::AcquireRegister() {
+  top_register_++;
+  if (register_stack_.size() == top_register_) {
+    register_stack_.push_back(method_->MakeRegister());
+  }
+  return register_stack_[top_register_];
+}
+
+void DexViewBuilder::ReleaseRegister() { top_register_--; }
+
+dex::Value DexViewBuilder::GetCurrentView() const { return view_stack_.back().view; }
+dex::Value DexViewBuilder::GetCurrentLayoutParams() const {
+  return view_stack_.back().layout_params.value();
+}
+dex::Value DexViewBuilder::GetParentView() const {
+  return view_stack_[view_stack_.size() - 2].view;
+}
+
+void DexViewBuilder::PopViewStack() {
+  const auto& top = view_stack_.back();
+  // release the layout params if we have them
+  if (top.layout_params.has_value()) {
+    ReleaseRegister();
+  }
+  // Unconditionally release the view register.
+  ReleaseRegister();
+  view_stack_.pop_back();
+}
+
+}  // namespace startop
\ No newline at end of file
diff --git a/startop/view_compiler/dex_layout_compiler.h b/startop/view_compiler/dex_layout_compiler.h
new file mode 100644
index 000000000000..170a1a610297
--- /dev/null
+++ b/startop/view_compiler/dex_layout_compiler.h
@@ -0,0 +1,118 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef DEX_LAYOUT_COMPILER_H_
+#define DEX_LAYOUT_COMPILER_H_
+
+#include "dex_builder.h"
+
+#include <codecvt>
+#include <locale>
+#include <string>
+#include <vector>
+
+namespace startop {
+
+// This visitor does the actual view compilation, using a supplied builder.
+template <typename Builder>
+class LayoutCompilerVisitor {
+ public:
+  explicit LayoutCompilerVisitor(Builder* builder) : builder_{builder} {}
+
+  void VisitStartDocument() { builder_->Start(); }
+  void VisitEndDocument() { builder_->Finish(); }
+  void VisitStartTag(const std::u16string& name) {
+    parent_stack_.push_back(ViewEntry{
+        std::wstring_convert<std::codecvt_utf8_utf16<char16_t>, char16_t>{}.to_bytes(name), {}});
+  }
+  void VisitEndTag() {
+    auto entry = parent_stack_.back();
+    parent_stack_.pop_back();
+
+    if (parent_stack_.empty()) {
+      GenerateCode(entry);
+    } else {
+      parent_stack_.back().children.push_back(entry);
+    }
+  }
+
+ private:
+  struct ViewEntry {
+    std::string name;
+    std::vector<ViewEntry> children;
+  };
+
+  void GenerateCode(const ViewEntry& view) {
+    builder_->StartView(view.name, !view.children.empty());
+    for (const auto& child : view.children) {
+      GenerateCode(child);
+    }
+    builder_->FinishView();
+  }
+
+  Builder* builder_;
+
+  std::vector<ViewEntry> parent_stack_;
+};
+
+class DexViewBuilder {
+ public:
+  DexViewBuilder(dex::MethodBuilder* method);
+
+  void Start();
+  void Finish();
+  void StartView(const std::string& name, bool is_viewgroup);
+  void FinishView();
+
+ private:
+  // Accessors for the stack of views that are under construction.
+  dex::Value AcquireRegister();
+  void ReleaseRegister();
+  dex::Value GetCurrentView() const;
+  dex::Value GetCurrentLayoutParams() const;
+  dex::Value GetParentView() const;
+  void PopViewStack();
+
+  dex::MethodBuilder* method_;
+
+  // Registers used for code generation
+  dex::Value const context_;
+  dex::Value const resid_;
+  const dex::Value inflater_;
+  const dex::Value xml_;
+  const dex::Value attrs_;
+  const dex::Value classname_tmp_;
+
+  const dex::MethodDeclData xml_next_;
+  const dex::MethodDeclData try_create_view_;
+  const dex::MethodDeclData generate_layout_params_;
+  const dex::MethodDeclData add_view_;
+
+  // used for keeping track of which registers are in use
+  size_t top_register_{0};
+  std::vector<dex::Value> register_stack_;
+
+  // Keep track of the views currently in progress.
+  struct ViewEntry {
+    dex::Value view;
+    std::optional<dex::Value> layout_params;
+  };
+  std::vector<ViewEntry> view_stack_;
+};
+
+}  // namespace startop
+
+#endif  // DEX_LAYOUT_COMPILER_H_
diff --git a/startop/view_compiler/java_lang_builder.cc b/startop/view_compiler/java_lang_builder.cc
index 0b8754fc7096..920caeecf58e 100644
--- a/startop/view_compiler/java_lang_builder.cc
+++ b/startop/view_compiler/java_lang_builder.cc
@@ -67,7 +67,7 @@ void JavaLangViewBuilder::Finish() const {
           "}\n";     // end CompiledView
 }
 
-void JavaLangViewBuilder::StartView(const string& class_name) {
+void JavaLangViewBuilder::StartView(const string& class_name, bool /*is_viewgroup*/) {
   const string view_var = MakeVar("view");
   const string layout_var = MakeVar("layout");
   std::string parent = "null";
diff --git a/startop/view_compiler/java_lang_builder.h b/startop/view_compiler/java_lang_builder.h
index c8d20b23cd13..69356d3a6594 100644
--- a/startop/view_compiler/java_lang_builder.h
+++ b/startop/view_compiler/java_lang_builder.h
@@ -35,7 +35,7 @@ class JavaLangViewBuilder {
   void Finish() const;
 
   // Begin creating a view (i.e. process the opening tag)
-  void StartView(const std::string& class_name);
+  void StartView(const std::string& class_name, bool is_viewgroup);
   // Finish a view, after all of its child nodes have been processed.
   void FinishView();
 
diff --git a/startop/view_compiler/main.cc b/startop/view_compiler/main.cc
index 609bcf377b46..ae00187e1908 100644
--- a/startop/view_compiler/main.cc
+++ b/startop/view_compiler/main.cc
@@ -16,8 +16,11 @@
 
 #include "gflags/gflags.h"
 
+#include "android-base/stringprintf.h"
 #include "dex_builder.h"
+#include "dex_layout_compiler.h"
 #include "java_lang_builder.h"
+#include "layout_validation.h"
 #include "tinyxml_layout_parser.h"
 #include "util.h"
 
@@ -32,6 +35,12 @@
 namespace {
 
 using namespace tinyxml2;
+using android::base::StringPrintf;
+using startop::dex::ClassBuilder;
+using startop::dex::DexBuilder;
+using startop::dex::MethodBuilder;
+using startop::dex::Prototype;
+using startop::dex::TypeDescriptor;
 using namespace startop::util;
 using std::string;
 
@@ -41,34 +50,44 @@ DEFINE_bool(dex, false, "Generate a DEX file instead of Java");
 DEFINE_string(out, kStdoutFilename, "Where to write the generated class");
 DEFINE_string(package, "", "The package name for the generated class (required)");
 
-class ViewCompilerXmlVisitor : public XMLVisitor {
+template <typename Visitor>
+class XmlVisitorAdapter : public XMLVisitor {
  public:
-  explicit ViewCompilerXmlVisitor(JavaLangViewBuilder* builder) : builder_(builder) {}
+  explicit XmlVisitorAdapter(Visitor* visitor) : visitor_{visitor} {}
 
   bool VisitEnter(const XMLDocument& /*doc*/) override {
-    builder_->Start();
+    visitor_->VisitStartDocument();
     return true;
   }
 
   bool VisitExit(const XMLDocument& /*doc*/) override {
-    builder_->Finish();
+    visitor_->VisitEndDocument();
     return true;
   }
 
   bool VisitEnter(const XMLElement& element, const XMLAttribute* /*firstAttribute*/) override {
-    builder_->StartView(element.Name());
+    visitor_->VisitStartTag(
+        std::wstring_convert<std::codecvt_utf8_utf16<char16_t>, char16_t>{}.from_bytes(
+            element.Name()));
     return true;
   }
 
   bool VisitExit(const XMLElement& /*element*/) override {
-    builder_->FinishView();
+    visitor_->VisitEndTag();
     return true;
   }
 
  private:
-  JavaLangViewBuilder* builder_;
+  Visitor* visitor_;
 };
 
+template <typename Builder>
+void CompileLayout(XMLDocument* xml, Builder* builder) {
+  startop::LayoutCompilerVisitor visitor{builder};
+  XmlVisitorAdapter<decltype(visitor)> adapter{&visitor};
+  xml->Accept(&adapter);
+}
+
 }  // end namespace
 
 int main(int argc, char** argv) {
@@ -88,16 +107,8 @@ int main(int argc, char** argv) {
     return 1;
   }
 
-  if (FLAGS_dex) {
-    startop::dex::WriteTestDexFile("test.dex");
-    return 0;
-  }
-
   const char* const filename = argv[kFileNameParam];
-  const string layout_name = FindLayoutNameFromFilename(filename);
-
-  // We want to generate Java language code to inflate exactly this layout. This means
-  // generating code to walk the resource XML too.
+  const string layout_name = startop::util::FindLayoutNameFromFilename(filename);
 
   XMLDocument xml;
   xml.LoadFile(filename);
@@ -108,15 +119,34 @@ int main(int argc, char** argv) {
     return 1;
   }
 
+  const bool is_stdout = FLAGS_out == kStdoutFilename;
+
   std::ofstream outfile;
-  if (FLAGS_out != kStdoutFilename) {
+  if (!is_stdout) {
     outfile.open(FLAGS_out);
   }
-  JavaLangViewBuilder builder{
-      FLAGS_package, layout_name, FLAGS_out == kStdoutFilename ? std::cout : outfile};
-
-  ViewCompilerXmlVisitor visitor{&builder};
-  xml.Accept(&visitor);
 
+  if (FLAGS_dex) {
+    DexBuilder dex_file;
+    string class_name = StringPrintf("%s.CompiledView", FLAGS_package.c_str());
+    ClassBuilder compiled_view{dex_file.MakeClass(class_name)};
+    MethodBuilder method{compiled_view.CreateMethod(
+        layout_name,
+        Prototype{TypeDescriptor::FromClassname("android.view.View"),
+                  TypeDescriptor::FromClassname("android.content.Context"),
+                  TypeDescriptor::Int()})};
+    startop::DexViewBuilder builder{&method};
+    CompileLayout(&xml, &builder);
+    method.Encode();
+
+    slicer::MemView image{dex_file.CreateImage()};
+
+    (is_stdout ? std::cout : outfile).write(image.ptr<const char>(), image.size());
+  } else {
+    // Generate Java language output.
+    JavaLangViewBuilder builder{FLAGS_package, layout_name, is_stdout ? std::cout : outfile};
+
+    CompileLayout(&xml, &builder);
+  }
   return 0;
 }
-- 
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