compiler/driver/dex_compilation_unit.h

/*
 * Copyright (C) 2012 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_COMPILER_DRIVER_DEX_COMPILATION_UNIT_H_
#define ART_COMPILER_DRIVER_DEX_COMPILATION_UNIT_H_

#include <stdint.h>

#include "base/arena_object.h"
#include "dex/code_item_accessors.h"
#include "dex/dex_file.h"
#include "handle.h"

namespace art {
namespace mirror {
class Class;
class ClassLoader;
class DexCache;
}  // namespace mirror
class ClassLinker;
class VerifiedMethod;

class DexCompilationUnit : public DeletableArenaObject<kArenaAllocMisc> {
 public:
  DexCompilationUnit(Handle<mirror::ClassLoader> class_loader,
                     ClassLinker* class_linker,
                     const DexFile& dex_file,
                     const dex::CodeItem* code_item,
                     uint16_t class_def_idx,
                     uint32_t method_idx,
                     uint32_t access_flags,
                     const VerifiedMethod* verified_method,
                     Handle<mirror::DexCache> dex_cache,
                     Handle<mirror::Class> compiling_class = Handle<mirror::Class>());

  Handle<mirror::ClassLoader> GetClassLoader() const {
    return class_loader_;
  }

  ClassLinker* GetClassLinker() const {
    return class_linker_;
  }

  const DexFile* GetDexFile() const {
    return dex_file_;
  }

  uint16_t GetClassDefIndex() const {
    return class_def_idx_;
  }

  uint32_t GetDexMethodIndex() const {
    return dex_method_idx_;
  }

  const dex::CodeItem* GetCodeItem() const {
    return code_item_;
  }

  const char* GetShorty() const {
    const dex::MethodId& method_id = dex_file_->GetMethodId(dex_method_idx_);
    return dex_file_->GetMethodShorty(method_id);
  }

  const char* GetShorty(uint32_t* shorty_len) const {
    const dex::MethodId& method_id = dex_file_->GetMethodId(dex_method_idx_);
    return dex_file_->GetMethodShorty(method_id, shorty_len);
  }

  uint32_t GetAccessFlags() const {
    return access_flags_;
  }

  bool IsConstructor() const {
    return ((access_flags_ & kAccConstructor) != 0);
  }

  bool IsNative() const {
    return ((access_flags_ & kAccNative) != 0);
  }

  bool IsStatic() const {
    return ((access_flags_ & kAccStatic) != 0);
  }

  bool IsSynchronized() const {
    return ((access_flags_ & kAccSynchronized) != 0);
  }

  const VerifiedMethod* GetVerifiedMethod() const {
    return verified_method_;
  }

  void ClearVerifiedMethod() {
    verified_method_ = nullptr;
  }

  const std::string& GetSymbol();

  Handle<mirror::DexCache> GetDexCache() const {
    return dex_cache_;
  }

  const CodeItemDataAccessor& GetCodeItemAccessor() const {
    return code_item_accessor_;
  }

  Handle<mirror::Class> GetCompilingClass() const {
    return compiling_class_;
  }

  // Does this <init> method require a constructor barrier (prior to the return)?
  // The answer is "yes", if and only if the class has any instance final fields.
  // (This must not be called for any non-<init> methods; the answer would be "no").
  //
  // ---
  //
  // JLS 17.5.1 "Semantics of final fields" mandates that all final fields are frozen at the end
  // of the invoked constructor. The constructor barrier is a conservative implementation means of
  // enforcing the freezes happen-before the object being constructed is observable by another
  // thread.
  //
  // Note: This question only makes sense for instance constructors;
  // static constructors (despite possibly having finals) never need
  // a barrier.
  //
  // JLS 12.4.2 "Detailed Initialization Procedure" approximately describes
  // class initialization as:
  //
  //   lock(class.lock)
  //     class.state = initializing
  //   unlock(class.lock)
  //
  //   invoke <clinit>
  //
  //   lock(class.lock)
  //     class.state = initialized
  //   unlock(class.lock)              <-- acts as a release
  //
  // The last operation in the above example acts as an atomic release
  // for any stores in <clinit>, which ends up being stricter
  // than what a constructor barrier needs.
  //
  // See also QuasiAtomic::ThreadFenceForConstructor().
  bool RequiresConstructorBarrier() const;

 private:
  const Handle<mirror::ClassLoader> class_loader_;

  ClassLinker* const class_linker_;

  const DexFile* const dex_file_;

  const dex::CodeItem* const code_item_;
  const uint16_t class_def_idx_;
  const uint32_t dex_method_idx_;
  const uint32_t access_flags_;
  const VerifiedMethod* verified_method_;

  const Handle<mirror::DexCache> dex_cache_;

  const CodeItemDataAccessor code_item_accessor_;

  Handle<mirror::Class> compiling_class_;

  std::string symbol_;
};

}  // namespace art

#endif  // ART_COMPILER_DRIVER_DEX_COMPILATION_UNIT_H_