Revert^8 "Make sure that const-class linkage is preserved."

Replaced two ReaderMutexLocks with WriterMutexLocks.
Removed some unnecessary debugging output.

Test: m test-art-host
Bug: 30627598
Original-Change-Id: Ie9b721464b4e9a5dcce8df8095548e983bba1fe8

This reverts commit 2c8c6b63da6ecb2ac701cc30f9b4fa4a8eea5cc8.

Change-Id: I3a1aeecf64e4b202cef61cceb248d48106a2f4a6

1 files changed, 67 insertions, 21 deletions

diff --git a/compiler/image_writer.cc b/compiler/image_writer.cc
index 0fb2a8bf17..a47e711c28 100644
--- a/compiler/image_writer.cc
+++ b/compiler/image_writer.cc
@@ -838,21 +838,73 @@ bool ImageWriter::KeepClass(Class* klass) {
   return true;
 }
 
-class ImageWriter::NonImageClassesVisitor : public ClassVisitor {
+class ImageWriter::PruneClassesVisitor : public ClassVisitor {
  public:
-  explicit NonImageClassesVisitor(ImageWriter* image_writer) : image_writer_(image_writer) {}
+  PruneClassesVisitor(ImageWriter* image_writer, ObjPtr<mirror::ClassLoader> class_loader)
+      : image_writer_(image_writer),
+        class_loader_(class_loader),
+        classes_to_prune_(),
+        defined_class_count_(0u) { }
 
-  bool operator()(ObjPtr<Class> klass) OVERRIDE REQUIRES_SHARED(Locks::mutator_lock_) {
+  bool operator()(ObjPtr<mirror::Class> klass) OVERRIDE REQUIRES_SHARED(Locks::mutator_lock_) {
     if (!image_writer_->KeepClass(klass.Ptr())) {
       classes_to_prune_.insert(klass.Ptr());
+      if (klass->GetClassLoader() == class_loader_) {
+        ++defined_class_count_;
+      }
     }
     return true;
   }
 
+  size_t Prune() REQUIRES_SHARED(Locks::mutator_lock_) {
+    ClassTable* class_table =
+        Runtime::Current()->GetClassLinker()->ClassTableForClassLoader(class_loader_);
+    for (mirror::Class* klass : classes_to_prune_) {
+      std::string storage;
+      const char* descriptor = klass->GetDescriptor(&storage);
+      bool result = class_table->Remove(descriptor);
+      DCHECK(result);
+      DCHECK(!class_table->Remove(descriptor)) << descriptor;
+    }
+    return defined_class_count_;
+  }
+
+ private:
+  ImageWriter* const image_writer_;
+  const ObjPtr<mirror::ClassLoader> class_loader_;
   std::unordered_set<mirror::Class*> classes_to_prune_;
+  size_t defined_class_count_;
+};
+
+class ImageWriter::PruneClassLoaderClassesVisitor : public ClassLoaderVisitor {
+ public:
+  explicit PruneClassLoaderClassesVisitor(ImageWriter* image_writer)
+      : image_writer_(image_writer), removed_class_count_(0) {}
+
+  virtual void Visit(ObjPtr<mirror::ClassLoader> class_loader) OVERRIDE
+      REQUIRES_SHARED(Locks::mutator_lock_) {
+    PruneClassesVisitor classes_visitor(image_writer_, class_loader);
+    ClassTable* class_table =
+        Runtime::Current()->GetClassLinker()->ClassTableForClassLoader(class_loader);
+    class_table->Visit(classes_visitor);
+    removed_class_count_ += classes_visitor.Prune();
+  }
+
+  size_t GetRemovedClassCount() const {
+    return removed_class_count_;
+  }
+
+ private:
   ImageWriter* const image_writer_;
+  size_t removed_class_count_;
 };
 
+void ImageWriter::VisitClassLoaders(ClassLoaderVisitor* visitor) {
+  WriterMutexLock mu(Thread::Current(), *Locks::classlinker_classes_lock_);
+  visitor->Visit(nullptr);  // Visit boot class loader.
+  Runtime::Current()->GetClassLinker()->VisitClassLoaders(visitor);
+}
+
 void ImageWriter::PruneNonImageClasses() {
   Runtime* runtime = Runtime::Current();
   ClassLinker* class_linker = runtime->GetClassLinker();
@@ -862,21 +914,11 @@ void ImageWriter::PruneNonImageClasses() {
   // path dex caches.
   class_linker->ClearClassTableStrongRoots();
 
-  // Make a list of classes we would like to prune.
-  NonImageClassesVisitor visitor(this);
-  class_linker->VisitClasses(&visitor);
-
   // Remove the undesired classes from the class roots.
-  VLOG(compiler) << "Pruning " << visitor.classes_to_prune_.size() << " classes";
-  for (mirror::Class* klass : visitor.classes_to_prune_) {
-    std::string temp;
-    const char* name = klass->GetDescriptor(&temp);
-    VLOG(compiler) << "Pruning class " << name;
-    if (!compile_app_image_) {
-      DCHECK(IsBootClassLoaderClass(klass));
-    }
-    bool result = class_linker->RemoveClass(name, klass->GetClassLoader());
-    DCHECK(result);
+  {
+    PruneClassLoaderClassesVisitor class_loader_visitor(this);
+    VisitClassLoaders(&class_loader_visitor);
+    VLOG(compiler) << "Pruned " << class_loader_visitor.GetRemovedClassCount() << " classes";
   }
 
   // Clear references to removed classes from the DexCaches.
@@ -1508,8 +1550,10 @@ void ImageWriter::CalculateNewObjectOffsets() {
     }
     // Calculate the size of the class table.
     ReaderMutexLock mu(self, *Locks::classlinker_classes_lock_);
-    DCHECK_EQ(image_info.class_table_->NumZygoteClasses(), 0u);
-    if (image_info.class_table_->NumNonZygoteClasses() != 0u) {
+    CHECK_EQ(class_loaders_.size(), compile_app_image_ ? 1u : 0u);
+    mirror::ClassLoader* class_loader = compile_app_image_ ? *class_loaders_.begin() : nullptr;
+    DCHECK_EQ(image_info.class_table_->NumZygoteClasses(class_loader), 0u);
+    if (image_info.class_table_->NumNonZygoteClasses(class_loader) != 0u) {
       image_info.class_table_bytes_ += image_info.class_table_->WriteToMemory(nullptr);
     }
   }
@@ -1854,8 +1898,10 @@ void ImageWriter::CopyAndFixupNativeData(size_t oat_index) {
     // above comment for intern tables.
     ClassTable temp_class_table;
     temp_class_table.ReadFromMemory(class_table_memory_ptr);
-    CHECK_EQ(temp_class_table.NumZygoteClasses(), table->NumNonZygoteClasses() +
-             table->NumZygoteClasses());
+    CHECK_EQ(class_loaders_.size(), compile_app_image_ ? 1u : 0u);
+    mirror::ClassLoader* class_loader = compile_app_image_ ? *class_loaders_.begin() : nullptr;
+    CHECK_EQ(temp_class_table.NumZygoteClasses(class_loader),
+             table->NumNonZygoteClasses(class_loader) + table->NumZygoteClasses(class_loader));
     UnbufferedRootVisitor visitor(&root_visitor, RootInfo(kRootUnknown));
     temp_class_table.VisitRoots(visitor);
   }