runtime/class_linker-inl.h

/*
 * Copyright (C) 2011 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 ART_RUNTIME_CLASS_LINKER_INL_H_
#define ART_RUNTIME_CLASS_LINKER_INL_H_

#include "class_linker.h"
#include "gc_root-inl.h"
#include "gc/heap-inl.h"
#include "mirror/art_field.h"
#include "mirror/class_loader.h"
#include "mirror/dex_cache-inl.h"
#include "mirror/iftable.h"
#include "mirror/object_array.h"
#include "handle_scope-inl.h"

namespace art {

inline bool ClassLinker::IsInBootClassPath(const char* descriptor) {
  DexFile::ClassPathEntry pair = DexFile::FindInClassPath(descriptor, boot_class_path_);
  return pair.second != nullptr;
}

inline mirror::Class* ClassLinker::FindSystemClass(Thread* self, const char* descriptor) {
  return FindClass(self, descriptor, NullHandle<mirror::ClassLoader>());
}

inline mirror::Class* ClassLinker::FindArrayClass(Thread* self, mirror::Class** element_class) {
  for (size_t i = 0; i < kFindArrayCacheSize; ++i) {
    // Read the cached array class once to avoid races with other threads setting it.
    mirror::Class* array_class = find_array_class_cache_[i].Read();
    if (array_class != nullptr && array_class->GetComponentType() == *element_class) {
      return array_class;
    }
  }
  DCHECK(!(*element_class)->IsPrimitiveVoid());
  std::string descriptor = "[";
  std::string temp;
  descriptor += (*element_class)->GetDescriptor(&temp);
  StackHandleScope<2> hs(Thread::Current());
  Handle<mirror::ClassLoader> class_loader(hs.NewHandle((*element_class)->GetClassLoader()));
  HandleWrapper<mirror::Class> h_element_class(hs.NewHandleWrapper(element_class));
  mirror::Class* array_class = FindClass(self, descriptor.c_str(), class_loader);
  // Benign races in storing array class and incrementing index.
  size_t victim_index = find_array_class_cache_next_victim_;
  find_array_class_cache_[victim_index] = GcRoot<mirror::Class>(array_class);
  find_array_class_cache_next_victim_ = (victim_index + 1) % kFindArrayCacheSize;
  return array_class;
}

inline mirror::String* ClassLinker::ResolveString(uint32_t string_idx,
                                                  mirror::ArtMethod* referrer) {
  mirror::String* resolved_string = referrer->GetDexCacheStrings()->Get(string_idx);
  if (UNLIKELY(resolved_string == NULL)) {
    mirror::Class* declaring_class = referrer->GetDeclaringClass();
    StackHandleScope<1> hs(Thread::Current());
    Handle<mirror::DexCache> dex_cache(hs.NewHandle(declaring_class->GetDexCache()));
    const DexFile& dex_file = *dex_cache->GetDexFile();
    resolved_string = ResolveString(dex_file, string_idx, dex_cache);
    if (resolved_string != nullptr) {
      DCHECK_EQ(dex_cache->GetResolvedString(string_idx), resolved_string);
    }
  }
  return resolved_string;
}

inline mirror::Class* ClassLinker::ResolveType(uint16_t type_idx,
                                               mirror::ArtMethod* referrer) {
  mirror::Class* resolved_type = referrer->GetDexCacheResolvedType(type_idx);
  if (UNLIKELY(resolved_type == nullptr)) {
    mirror::Class* declaring_class = referrer->GetDeclaringClass();
    StackHandleScope<2> hs(Thread::Current());
    Handle<mirror::DexCache> dex_cache(hs.NewHandle(declaring_class->GetDexCache()));
    Handle<mirror::ClassLoader> class_loader(hs.NewHandle(declaring_class->GetClassLoader()));
    const DexFile& dex_file = *dex_cache->GetDexFile();
    resolved_type = ResolveType(dex_file, type_idx, dex_cache, class_loader);
    // Note: We cannot check here to see whether we added the type to the cache. The type
    //       might be an erroneous class, which results in it being hidden from us.
  }
  return resolved_type;
}

inline mirror::Class* ClassLinker::ResolveType(uint16_t type_idx, mirror::ArtField* referrer) {
  mirror::Class* declaring_class = referrer->GetDeclaringClass();
  mirror::DexCache* dex_cache_ptr = declaring_class->GetDexCache();
  mirror::Class* resolved_type = dex_cache_ptr->GetResolvedType(type_idx);
  if (UNLIKELY(resolved_type == NULL)) {
    StackHandleScope<2> hs(Thread::Current());
    Handle<mirror::DexCache> dex_cache(hs.NewHandle(dex_cache_ptr));
    Handle<mirror::ClassLoader> class_loader(hs.NewHandle(declaring_class->GetClassLoader()));
    const DexFile& dex_file = *dex_cache->GetDexFile();
    resolved_type = ResolveType(dex_file, type_idx, dex_cache, class_loader);
    // Note: We cannot check here to see whether we added the type to the cache. The type
    //       might be an erroneous class, which results in it being hidden from us.
  }
  return resolved_type;
}

inline mirror::ArtMethod* ClassLinker::GetResolvedMethod(uint32_t method_idx,
                                                         mirror::ArtMethod* referrer,
                                                         InvokeType type) {
  mirror::ArtMethod* resolved_method = referrer->GetDexCacheResolvedMethod(method_idx);
  if (resolved_method == nullptr || resolved_method->IsRuntimeMethod()) {
    return nullptr;
  }
  return resolved_method;
}

inline mirror::ArtMethod* ClassLinker::ResolveMethod(Thread* self, uint32_t method_idx,
                                                     mirror::ArtMethod** referrer,
                                                     InvokeType type) {
  mirror::ArtMethod* resolved_method = GetResolvedMethod(method_idx, *referrer, type);
  if (LIKELY(resolved_method != nullptr)) {
    return resolved_method;
  }
  mirror::Class* declaring_class = (*referrer)->GetDeclaringClass();
  StackHandleScope<3> hs(self);
  Handle<mirror::DexCache> h_dex_cache(hs.NewHandle(declaring_class->GetDexCache()));
  Handle<mirror::ClassLoader> h_class_loader(hs.NewHandle(declaring_class->GetClassLoader()));
  HandleWrapper<mirror::ArtMethod> h_referrer(hs.NewHandleWrapper(referrer));
  const DexFile* dex_file = h_dex_cache->GetDexFile();
  resolved_method = ResolveMethod(*dex_file, method_idx, h_dex_cache, h_class_loader, h_referrer,
                                  type);
  // Note: We cannot check here to see whether we added the method to the cache. It
  //       might be an erroneous class, which results in it being hidden from us.
  return resolved_method;
}

inline mirror::ArtField* ClassLinker::GetResolvedField(uint32_t field_idx,
                                                       mirror::Class* field_declaring_class) {
  return field_declaring_class->GetDexCache()->GetResolvedField(field_idx);
}

inline mirror::ArtField* ClassLinker::ResolveField(uint32_t field_idx, mirror::ArtMethod* referrer,
                                                   bool is_static) {
  mirror::Class* declaring_class = referrer->GetDeclaringClass();
  mirror::ArtField* resolved_field = GetResolvedField(field_idx, declaring_class);
  if (UNLIKELY(resolved_field == NULL)) {
    StackHandleScope<2> hs(Thread::Current());
    Handle<mirror::DexCache> dex_cache(hs.NewHandle(declaring_class->GetDexCache()));
    Handle<mirror::ClassLoader> class_loader(hs.NewHandle(declaring_class->GetClassLoader()));
    const DexFile& dex_file = *dex_cache->GetDexFile();
    resolved_field = ResolveField(dex_file, field_idx, dex_cache, class_loader, is_static);
    // Note: We cannot check here to see whether we added the field to the cache. The type
    //       might be an erroneous class, which results in it being hidden from us.
  }
  return resolved_field;
}

template <class T>
inline mirror::ObjectArray<T>* ClassLinker::AllocObjectArray(Thread* self, size_t length) {
  return mirror::ObjectArray<T>::Alloc(self, GetClassRoot(kObjectArrayClass), length);
}

inline mirror::ObjectArray<mirror::Class>* ClassLinker::AllocClassArray(Thread* self,
                                                                        size_t length) {
  return mirror::ObjectArray<mirror::Class>::Alloc(self, GetClassRoot(kClassArrayClass), length);
}

inline mirror::ObjectArray<mirror::String>* ClassLinker::AllocStringArray(Thread* self,
                                                                          size_t length) {
  return mirror::ObjectArray<mirror::String>::Alloc(self, GetClassRoot(kJavaLangStringArrayClass),
                                                    length);
}

inline mirror::ObjectArray<mirror::ArtMethod>* ClassLinker::AllocArtMethodArray(Thread* self,
                                                                                size_t length) {
  return mirror::ObjectArray<mirror::ArtMethod>::Alloc(self,
      GetClassRoot(kJavaLangReflectArtMethodArrayClass), length);
}

inline mirror::IfTable* ClassLinker::AllocIfTable(Thread* self, size_t ifcount) {
  return down_cast<mirror::IfTable*>(
      mirror::IfTable::Alloc(self, GetClassRoot(kObjectArrayClass),
                             ifcount * mirror::IfTable::kMax));
}

inline mirror::ObjectArray<mirror::ArtField>* ClassLinker::AllocArtFieldArray(Thread* self,
                                                                              size_t length) {
  gc::Heap* const heap = Runtime::Current()->GetHeap();
  // Can't have movable field arrays for mark compact since we need these arrays to always be valid
  // so that we can do Object::VisitReferences in the case where the fields don't fit in the
  // reference offsets word.
  return mirror::ObjectArray<mirror::ArtField>::Alloc(
      self, GetClassRoot(kJavaLangReflectArtFieldArrayClass), length,
      kMoveFieldArrays ? heap->GetCurrentAllocator() : heap->GetCurrentNonMovingAllocator());
}

inline mirror::Class* ClassLinker::GetClassRoot(ClassRoot class_root)
    SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
  DCHECK(!class_roots_.IsNull());
  mirror::ObjectArray<mirror::Class>* class_roots = class_roots_.Read();
  mirror::Class* klass = class_roots->Get(class_root);
  DCHECK(klass != NULL);
  return klass;
}

inline mirror::DexCache* ClassLinker::GetDexCache(size_t idx) {
  dex_lock_.AssertSharedHeld(Thread::Current());
  DCHECK(idx < dex_caches_.size());
  return dex_caches_[idx].Read();
}

}  // namespace art

#endif  // ART_RUNTIME_CLASS_LINKER_INL_H_