Allow dex2oat to create a full class loader context

We previously checked that dex2oat sees only a single class loader. This
CL removes the restriction and enables dex2oat to create and compile with
a full class loader context.

Test: m test-art-host
Bug: 38138251
Change-Id: I03e75a75757995ce8ce3addf0bc0a708e18ac050
diff --git a/runtime/class_loader_context_test.cc b/runtime/class_loader_context_test.cc
index 659db4b..1b46f67 100644
--- a/runtime/class_loader_context_test.cc
+++ b/runtime/class_loader_context_test.cc
@@ -117,6 +117,24 @@
     ASSERT_FALSE(context->special_shared_library_);
   }
 
+  void VerifyClassLoaderDexFiles(ScopedObjectAccess& soa,
+                                 Handle<mirror::ClassLoader> class_loader,
+                                 jclass type,
+                                 std::vector<const DexFile*>& expected_dex_files)
+      REQUIRES_SHARED(Locks::mutator_lock_) {
+    ASSERT_TRUE(class_loader->GetClass() == soa.Decode<mirror::Class>(type));
+
+    std::vector<const DexFile*> class_loader_dex_files = GetDexFiles(soa, class_loader);
+    ASSERT_EQ(expected_dex_files.size(), class_loader_dex_files.size());
+
+    for (size_t i = 0; i < expected_dex_files.size(); i++) {
+      ASSERT_EQ(expected_dex_files[i]->GetLocation(),
+                class_loader_dex_files[i]->GetLocation());
+      ASSERT_EQ(expected_dex_files[i]->GetLocationChecksum(),
+                class_loader_dex_files[i]->GetLocationChecksum());
+    }
+  }
+
  private:
   void VerifyClassLoaderInfo(ClassLoaderContext* context,
                              size_t index,
@@ -246,7 +264,7 @@
 
   ScopedObjectAccess soa(Thread::Current());
 
-  StackHandleScope<2> hs(soa.Self());
+  StackHandleScope<1> hs(soa.Self());
   Handle<mirror::ClassLoader> class_loader = hs.NewHandle(
       soa.Decode<mirror::ClassLoader>(jclass_loader));
 
@@ -255,25 +273,17 @@
   ASSERT_TRUE(class_loader->GetParent()->GetClass() ==
       soa.Decode<mirror::Class>(WellKnownClasses::java_lang_BootClassLoader));
 
-
-  std::vector<const DexFile*> class_loader_dex_files = GetDexFiles(jclass_loader);
-  ASSERT_EQ(classpath_dex.size() + compilation_sources.size(), class_loader_dex_files.size());
-
-  // The classpath dex files must come first.
-  for (size_t i = 0; i < classpath_dex.size(); i++) {
-    ASSERT_EQ(classpath_dex[i]->GetLocation(),
-              class_loader_dex_files[i]->GetLocation());
-    ASSERT_EQ(classpath_dex[i]->GetLocationChecksum(),
-              class_loader_dex_files[i]->GetLocationChecksum());
+  // For the first class loader the class path dex files must come first and then the
+  // compilation sources.
+  std::vector<const DexFile*> expected_classpath = MakeNonOwningPointerVector(classpath_dex);
+  for (auto& dex : compilation_sources_raw) {
+    expected_classpath.push_back(dex);
   }
 
-  // The compilation dex files must come second.
-  for (size_t i = 0, k = classpath_dex.size(); i < compilation_sources.size(); i++, k++) {
-    ASSERT_EQ(compilation_sources[i]->GetLocation(),
-              class_loader_dex_files[k]->GetLocation());
-    ASSERT_EQ(compilation_sources[i]->GetLocationChecksum(),
-              class_loader_dex_files[k]->GetLocationChecksum());
-  }
+  VerifyClassLoaderDexFiles(soa,
+                            class_loader,
+                            WellKnownClasses::dalvik_system_PathClassLoader,
+                            expected_classpath);
 }
 
 TEST_F(ClassLoaderContextTest, CreateClassLoaderWithEmptyContext) {
@@ -290,28 +300,90 @@
 
   ScopedObjectAccess soa(Thread::Current());
 
-  StackHandleScope<2> hs(soa.Self());
+  StackHandleScope<1> hs(soa.Self());
   Handle<mirror::ClassLoader> class_loader = hs.NewHandle(
       soa.Decode<mirror::ClassLoader>(jclass_loader));
 
-  ASSERT_TRUE(class_loader->GetClass() ==
-      soa.Decode<mirror::Class>(WellKnownClasses::dalvik_system_PathClassLoader));
+  // An empty context should create a single PathClassLoader with only the compilation sources.
+  VerifyClassLoaderDexFiles(soa,
+                            class_loader,
+                            WellKnownClasses::dalvik_system_PathClassLoader,
+                            compilation_sources_raw);
   ASSERT_TRUE(class_loader->GetParent()->GetClass() ==
       soa.Decode<mirror::Class>(WellKnownClasses::java_lang_BootClassLoader));
-
-
-  std::vector<const DexFile*> class_loader_dex_files = GetDexFiles(jclass_loader);
-
-  // The compilation sources should be the only files present in the class loader
-  ASSERT_EQ(compilation_sources.size(), class_loader_dex_files.size());
-  for (size_t i = 0; i < compilation_sources.size(); i++) {
-    ASSERT_EQ(compilation_sources[i]->GetLocation(),
-        class_loader_dex_files[i]->GetLocation());
-    ASSERT_EQ(compilation_sources[i]->GetLocationChecksum(),
-        class_loader_dex_files[i]->GetLocationChecksum());
-  }
 }
 
+TEST_F(ClassLoaderContextTest, CreateClassLoaderWithComplexChain) {
+  // Setup the context.
+  std::vector<std::unique_ptr<const DexFile>> classpath_dex_a = OpenTestDexFiles("ForClassLoaderA");
+  std::vector<std::unique_ptr<const DexFile>> classpath_dex_b = OpenTestDexFiles("ForClassLoaderB");
+  std::vector<std::unique_ptr<const DexFile>> classpath_dex_c = OpenTestDexFiles("ForClassLoaderC");
+  std::vector<std::unique_ptr<const DexFile>> classpath_dex_d = OpenTestDexFiles("ForClassLoaderD");
+
+  std::string context_spec =
+      "PCL[" + CreateClassPath(classpath_dex_a) + ":" + CreateClassPath(classpath_dex_b) + "];" +
+      "DLC[" + CreateClassPath(classpath_dex_c) + "];" +
+      "PCL[" + CreateClassPath(classpath_dex_d) + "]";
+
+  std::unique_ptr<ClassLoaderContext> context = ClassLoaderContext::Create(context_spec);
+  ASSERT_TRUE(context->OpenDexFiles(InstructionSet::kArm, ""));
+
+  // Setup the compilation sources.
+  std::vector<std::unique_ptr<const DexFile>> compilation_sources = OpenTestDexFiles("MultiDex");
+  std::vector<const DexFile*> compilation_sources_raw =
+      MakeNonOwningPointerVector(compilation_sources);
+
+  // Create the class loader.
+  jobject jclass_loader = context->CreateClassLoader(compilation_sources_raw);
+  ASSERT_TRUE(jclass_loader != nullptr);
+
+  // Verify the class loader.
+  ScopedObjectAccess soa(Thread::Current());
+
+  StackHandleScope<3> hs(soa.Self());
+  Handle<mirror::ClassLoader> class_loader_1 = hs.NewHandle(
+      soa.Decode<mirror::ClassLoader>(jclass_loader));
+
+  // Verify the first class loader
+
+  // For the first class loader the class path dex files must come first and then the
+  // compilation sources.
+  std::vector<const DexFile*> class_loader_1_dex_files =
+      MakeNonOwningPointerVector(classpath_dex_a);
+  for (auto& dex : classpath_dex_b) {
+    class_loader_1_dex_files.push_back(dex.get());
+  }
+  for (auto& dex : compilation_sources_raw) {
+    class_loader_1_dex_files.push_back(dex);
+  }
+  VerifyClassLoaderDexFiles(soa,
+                            class_loader_1,
+                            WellKnownClasses::dalvik_system_PathClassLoader,
+                            class_loader_1_dex_files);
+
+  // Verify the second class loader
+  Handle<mirror::ClassLoader> class_loader_2 = hs.NewHandle(class_loader_1->GetParent());
+  std::vector<const DexFile*> class_loader_2_dex_files =
+      MakeNonOwningPointerVector(classpath_dex_c);
+  VerifyClassLoaderDexFiles(soa,
+                            class_loader_2,
+                            WellKnownClasses::dalvik_system_DelegateLastClassLoader,
+                            class_loader_2_dex_files);
+
+  // Verify the third class loader
+  Handle<mirror::ClassLoader> class_loader_3 = hs.NewHandle(class_loader_2->GetParent());
+  std::vector<const DexFile*> class_loader_3_dex_files =
+      MakeNonOwningPointerVector(classpath_dex_d);
+  VerifyClassLoaderDexFiles(soa,
+                            class_loader_3,
+                            WellKnownClasses::dalvik_system_PathClassLoader,
+                            class_loader_3_dex_files);
+  // The last class loader should have the BootClassLoader as a parent.
+  ASSERT_TRUE(class_loader_3->GetParent()->GetClass() ==
+      soa.Decode<mirror::Class>(WellKnownClasses::java_lang_BootClassLoader));
+}
+
+
 TEST_F(ClassLoaderContextTest, RemoveSourceLocations) {
   std::unique_ptr<ClassLoaderContext> context =
       ClassLoaderContext::Create("PCL[a.dex]");
@@ -338,9 +410,8 @@
   std::vector<std::unique_ptr<const DexFile>> dex1 = OpenTestDexFiles("Main");
   std::vector<std::unique_ptr<const DexFile>> dex2 = OpenTestDexFiles("MyClass");
   std::string encoding = context->EncodeContextForOatFile("");
-  std::string expected_encoding = "PCL[" +
-      dex1[0]->GetLocation() + "*" + std::to_string(dex1[0]->GetLocationChecksum()) + ":" +
-      dex2[0]->GetLocation() + "*" + std::to_string(dex2[0]->GetLocationChecksum()) + "]";
+  std::string expected_encoding = "PCL[" + CreateClassPathWithChecksums(dex1) + ":" +
+      CreateClassPathWithChecksums(dex2) + "]";
   ASSERT_EQ(expected_encoding, context->EncodeContextForOatFile(""));
 }