runtime/object_utils.h - platform/art - Git at Google

 /*
  * 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_OBJECT_UTILS_H_
 #define ART_RUNTIME_OBJECT_UTILS_H_

 #include "class_linker.h"
 #include "dex_file.h"
 #include "monitor.h"
 #include "mirror/art_field.h"
 #include "mirror/art_method.h"
 #include "mirror/class.h"
 #include "mirror/dex_cache.h"
 #include "mirror/iftable.h"
 #include "mirror/proxy.h"
 #include "mirror/string.h"

 #include "runtime.h"
 #include "handle_scope-inl.h"

 #include <string>

 namespace art {

 template <typename T>
 class ObjectLock {
  public:
   ObjectLock(Thread* self, Handle<T> object) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
       : self_(self), obj_(object) {
     CHECK(object.Get() != nullptr);
     obj_->MonitorEnter(self_);
   }

   ~ObjectLock() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     obj_->MonitorExit(self_);
   }

   void WaitIgnoringInterrupts() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     Monitor::Wait(self_, obj_.Get(), 0, 0, false, kWaiting);
   }

   void Notify() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     obj_->Notify(self_);
   }

   void NotifyAll() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     obj_->NotifyAll(self_);
   }

  private:
   Thread* const self_;
   Handle<T> const obj_;
   DISALLOW_COPY_AND_ASSIGN(ObjectLock);
 };

 class FieldHelper {
  public:
   explicit FieldHelper(Handle<mirror::ArtField> f) : field_(f) {}

   void ChangeField(mirror::ArtField* new_f) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     DCHECK(new_f != nullptr);
     field_.Assign(new_f);
   }

   mirror::ArtField* GetField() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     return field_.Get();
   }

   mirror::Class* GetType(bool resolve = true) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     uint32_t field_index = field_->GetDexFieldIndex();
     if (UNLIKELY(field_->GetDeclaringClass()->IsProxyClass())) {
       return Runtime::Current()->GetClassLinker()->FindSystemClass(Thread::Current(),
                                                                    field_->GetTypeDescriptor());
     }
     const DexFile* dex_file = field_->GetDexFile();
     const DexFile::FieldId& field_id = dex_file->GetFieldId(field_index);
     mirror::Class* type = field_->GetDexCache()->GetResolvedType(field_id.type_idx_);
     if (resolve && (type == nullptr)) {
       type = Runtime::Current()->GetClassLinker()->ResolveType(field_id.type_idx_, field_.Get());
       CHECK(type != nullptr || Thread::Current()->IsExceptionPending());
     }
     return type;
   }

   // The returned const char* is only guaranteed to be valid for the lifetime of the FieldHelper.
   // If you need it longer, copy it into a std::string.
   const char* GetDeclaringClassDescriptor()
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     uint32_t field_index = field_->GetDexFieldIndex();
     if (UNLIKELY(field_->GetDeclaringClass()->IsProxyClass())) {
       DCHECK(field_->IsStatic());
       DCHECK_LT(field_index, 2U);
       // 0 == Class[] interfaces; 1 == Class[][] throws;
       declaring_class_descriptor_ = field_->GetDeclaringClass()->GetDescriptor();
       return declaring_class_descriptor_.c_str();
     }
     const DexFile* dex_file = field_->GetDexFile();
     const DexFile::FieldId& field_id = dex_file->GetFieldId(field_index);
     return dex_file->GetFieldDeclaringClassDescriptor(field_id);
   }

  private:
   Handle<mirror::ArtField> field_;
   std::string declaring_class_descriptor_;

   DISALLOW_COPY_AND_ASSIGN(FieldHelper);
 };

 class MethodHelper {
  public:
   explicit MethodHelper(Handle<mirror::ArtMethod> m) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
       : method_(m), shorty_(nullptr), shorty_len_(0) {
     SetMethod(m.Get());
   }

   void ChangeMethod(mirror::ArtMethod* new_m) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     DCHECK(new_m != nullptr);
     SetMethod(new_m);
     shorty_ = nullptr;
   }

   mirror::ArtMethod* GetMethod() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     return method_->GetInterfaceMethodIfProxy();
   }

   mirror::String* GetNameAsString(Thread* self) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     const DexFile* dex_file = method_->GetDexFile();
     mirror::ArtMethod* method = method_->GetInterfaceMethodIfProxy();
     uint32_t dex_method_idx = method->GetDexMethodIndex();
     const DexFile::MethodId& method_id = dex_file->GetMethodId(dex_method_idx);
     StackHandleScope<1> hs(self);
     Handle<mirror::DexCache> dex_cache(hs.NewHandle(method->GetDexCache()));
     return Runtime::Current()->GetClassLinker()->ResolveString(*dex_file, method_id.name_idx_,
                                                                dex_cache);
   }

   const char* GetShorty() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     const char* result = shorty_;
     if (result == nullptr) {
       result = method_->GetShorty(&shorty_len_);
       shorty_ = result;
     }
     return result;
   }

   uint32_t GetShortyLength() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     if (shorty_ == nullptr) {
       GetShorty();
     }
     return shorty_len_;
   }

   // Counts the number of references in the parameter list of the corresponding method.
   // Note: Thus does _not_ include "this" for non-static methods.
   uint32_t GetNumberOfReferenceArgsWithoutReceiver() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     const char* shorty = GetShorty();
     uint32_t refs = 0;
     for (uint32_t i = 1; i < shorty_len_ ; ++i) {
       if (shorty[i] == 'L') {
         refs++;
       }
     }

     return refs;
   }

   // May cause thread suspension due to GetClassFromTypeIdx calling ResolveType this caused a large
   // number of bugs at call sites.
   mirror::Class* GetReturnType(bool resolve = true) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     mirror::ArtMethod* method = GetMethod();
     const DexFile* dex_file = method->GetDexFile();
     const DexFile::MethodId& method_id = dex_file->GetMethodId(method->GetDexMethodIndex());
     const DexFile::ProtoId& proto_id = dex_file->GetMethodPrototype(method_id);
     uint16_t return_type_idx = proto_id.return_type_idx_;
     return GetClassFromTypeIdx(return_type_idx, resolve);
   }

   size_t NumArgs() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     // "1 +" because the first in Args is the receiver.
     // "- 1" because we don't count the return type.
     return (method_->IsStatic() ? 0 : 1) + GetShortyLength() - 1;
   }

   // Get the primitive type associated with the given parameter.
   Primitive::Type GetParamPrimitiveType(size_t param) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     CHECK_LT(param, NumArgs());
     if (GetMethod()->IsStatic()) {
       param++;  // 0th argument must skip return value at start of the shorty
     } else if (param == 0) {
       return Primitive::kPrimNot;
     }
     return Primitive::GetType(GetShorty()[param]);
   }

   // Is the specified parameter a long or double, where parameter 0 is 'this' for instance methods.
   bool IsParamALongOrDouble(size_t param) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     Primitive::Type type = GetParamPrimitiveType(param);
     return type == Primitive::kPrimLong || type == Primitive::kPrimDouble;
   }

   // Is the specified parameter a reference, where parameter 0 is 'this' for instance methods.
   bool IsParamAReference(size_t param) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     return GetParamPrimitiveType(param) == Primitive::kPrimNot;
   }

   bool HasSameNameAndSignature(MethodHelper* other) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     const DexFile* dex_file = method_->GetDexFile();
     const DexFile::MethodId& mid = dex_file->GetMethodId(GetMethod()->GetDexMethodIndex());
     if (method_->GetDexCache() == other->method_->GetDexCache()) {
       const DexFile::MethodId& other_mid =
           dex_file->GetMethodId(other->GetMethod()->GetDexMethodIndex());
       return mid.name_idx_ == other_mid.name_idx_ && mid.proto_idx_ == other_mid.proto_idx_;
     }
     const DexFile* other_dex_file = other->method_->GetDexFile();
     const DexFile::MethodId& other_mid =
         other_dex_file->GetMethodId(other->GetMethod()->GetDexMethodIndex());
     if (!DexFileStringEquals(dex_file, mid.name_idx_, other_dex_file, other_mid.name_idx_)) {
       return false;  // Name mismatch.
     }
     return dex_file->GetMethodSignature(mid) == other_dex_file->GetMethodSignature(other_mid);
   }

   bool HasSameSignatureWithDifferentClassLoaders(MethodHelper* other)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     if (UNLIKELY(GetReturnType() != other->GetReturnType())) {
       return false;
     }
     const DexFile::TypeList* types = method_->GetParameterTypeList();
     const DexFile::TypeList* other_types = other->method_->GetParameterTypeList();
     if (types == nullptr) {
       return (other_types == nullptr) || (other_types->Size() == 0);
     } else if (UNLIKELY(other_types == nullptr)) {
       return types->Size() == 0;
     }
     uint32_t num_types = types->Size();
     if (UNLIKELY(num_types != other_types->Size())) {
       return false;
     }
     for (uint32_t i = 0; i < num_types; ++i) {
       mirror::Class* param_type = GetClassFromTypeIdx(types->GetTypeItem(i).type_idx_);
       mirror::Class* other_param_type =
           other->GetClassFromTypeIdx(other_types->GetTypeItem(i).type_idx_);
       if (UNLIKELY(param_type != other_param_type)) {
         return false;
       }
     }
     return true;
   }

   mirror::Class* GetClassFromTypeIdx(uint16_t type_idx, bool resolve = true)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     mirror::ArtMethod* method = GetMethod();
     mirror::Class* type = method->GetDexCacheResolvedTypes()->Get(type_idx);
     if (type == nullptr && resolve) {
       type = Runtime::Current()->GetClassLinker()->ResolveType(type_idx, method);
       CHECK(type != nullptr || Thread::Current()->IsExceptionPending());
     }
     return type;
   }

   mirror::Class* GetDexCacheResolvedType(uint16_t type_idx)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     return GetMethod()->GetDexCacheResolvedTypes()->Get(type_idx);
   }

   mirror::String* ResolveString(uint32_t string_idx) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     mirror::ArtMethod* method = GetMethod();
     mirror::String* s = method->GetDexCacheStrings()->Get(string_idx);
     if (UNLIKELY(s == nullptr)) {
       StackHandleScope<1> hs(Thread::Current());
       Handle<mirror::DexCache> dex_cache(hs.NewHandle(method->GetDexCache()));
       s = Runtime::Current()->GetClassLinker()->ResolveString(*method->GetDexFile(), string_idx,
                                                               dex_cache);
     }
     return s;
   }

   uint32_t FindDexMethodIndexInOtherDexFile(const DexFile& other_dexfile)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     mirror::ArtMethod* method = GetMethod();
     const DexFile* dexfile = method->GetDexFile();
     if (dexfile == &other_dexfile) {
       return method->GetDexMethodIndex();
     }
     const DexFile::MethodId& mid = dexfile->GetMethodId(method->GetDexMethodIndex());
     const char* mid_declaring_class_descriptor = dexfile->StringByTypeIdx(mid.class_idx_);
     const DexFile::StringId* other_descriptor =
         other_dexfile.FindStringId(mid_declaring_class_descriptor);
     if (other_descriptor != nullptr) {
       const DexFile::TypeId* other_type_id =
           other_dexfile.FindTypeId(other_dexfile.GetIndexForStringId(*other_descriptor));
       if (other_type_id != nullptr) {
         const char* mid_name = dexfile->GetMethodName(mid);
         const DexFile::StringId* other_name = other_dexfile.FindStringId(mid_name);
         if (other_name != nullptr) {
           uint16_t other_return_type_idx;
           std::vector<uint16_t> other_param_type_idxs;
           bool success = other_dexfile.CreateTypeList(
               dexfile->GetMethodSignature(mid).ToString(), &other_return_type_idx,
               &other_param_type_idxs);
           if (success) {
             const DexFile::ProtoId* other_sig =
                 other_dexfile.FindProtoId(other_return_type_idx, other_param_type_idxs);
             if (other_sig != nullptr) {
               const  DexFile::MethodId* other_mid = other_dexfile.FindMethodId(
                   *other_type_id, *other_name, *other_sig);
               if (other_mid != nullptr) {
                 return other_dexfile.GetIndexForMethodId(*other_mid);
               }
             }
           }
         }
       }
     }
     return DexFile::kDexNoIndex;
   }

   // The name_and_signature_idx MUST point to a MethodId with the same name and signature in the
   // other_dexfile, such as the method index used to resolve this method in the other_dexfile.
   uint32_t FindDexMethodIndexInOtherDexFile(const DexFile& other_dexfile,
                                             uint32_t name_and_signature_idx)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     mirror::ArtMethod* method = GetMethod();
     const DexFile* dexfile = method->GetDexFile();
     const uint32_t dex_method_idx = method->GetDexMethodIndex();
     const DexFile::MethodId& mid = dexfile->GetMethodId(dex_method_idx);
     const DexFile::MethodId& name_and_sig_mid = other_dexfile.GetMethodId(name_and_signature_idx);
     DCHECK_STREQ(dexfile->GetMethodName(mid), other_dexfile.GetMethodName(name_and_sig_mid));
     DCHECK_EQ(dexfile->GetMethodSignature(mid), other_dexfile.GetMethodSignature(name_and_sig_mid));
     if (dexfile == &other_dexfile) {
       return dex_method_idx;
     }
     const char* mid_declaring_class_descriptor = dexfile->StringByTypeIdx(mid.class_idx_);
     const DexFile::StringId* other_descriptor =
         other_dexfile.FindStringId(mid_declaring_class_descriptor);
     if (other_descriptor != nullptr) {
       const DexFile::TypeId* other_type_id =
           other_dexfile.FindTypeId(other_dexfile.GetIndexForStringId(*other_descriptor));
       if (other_type_id != nullptr) {
         const DexFile::MethodId* other_mid = other_dexfile.FindMethodId(
             *other_type_id, other_dexfile.GetStringId(name_and_sig_mid.name_idx_),
             other_dexfile.GetProtoId(name_and_sig_mid.proto_idx_));
         if (other_mid != nullptr) {
           return other_dexfile.GetIndexForMethodId(*other_mid);
         }
       }
     }
     return DexFile::kDexNoIndex;
   }

  private:
   // Set the method_ field, for proxy methods looking up the interface method via the resolved
   // methods table.
   void SetMethod(mirror::ArtMethod* method) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     method_.Assign(method);
   }

   Handle<mirror::ArtMethod> method_;
   const char* shorty_;
   uint32_t shorty_len_;

   DISALLOW_COPY_AND_ASSIGN(MethodHelper);
 };

 }  // namespace art

 #endif  // ART_RUNTIME_OBJECT_UTILS_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_OBJECT_UTILS_H_
	#define ART_RUNTIME_OBJECT_UTILS_H_

	#include "class_linker.h"
	#include "dex_file.h"
	#include "monitor.h"
	#include "mirror/art_field.h"
	#include "mirror/art_method.h"
	#include "mirror/class.h"
	#include "mirror/dex_cache.h"
	#include "mirror/iftable.h"
	#include "mirror/proxy.h"
	#include "mirror/string.h"

	#include "runtime.h"
	#include "handle_scope-inl.h"

	#include <string>

	namespace art {

	template <typename T>
	class ObjectLock {
	public:
	ObjectLock(Thread* self, Handle<T> object) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
	: self_(self), obj_(object) {
	CHECK(object.Get() != nullptr);
	obj_->MonitorEnter(self_);
	}

	~ObjectLock() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	obj_->MonitorExit(self_);
	}

	void WaitIgnoringInterrupts() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	Monitor::Wait(self_, obj_.Get(), 0, 0, false, kWaiting);
	}

	void Notify() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	obj_->Notify(self_);
	}

	void NotifyAll() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	obj_->NotifyAll(self_);
	}

	private:
	Thread* const self_;
	Handle<T> const obj_;
	DISALLOW_COPY_AND_ASSIGN(ObjectLock);
	};

	class FieldHelper {
	public:
	explicit FieldHelper(Handle<mirror::ArtField> f) : field_(f) {}

	void ChangeField(mirror::ArtField* new_f) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	DCHECK(new_f != nullptr);
	field_.Assign(new_f);
	}

	mirror::ArtField* GetField() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	return field_.Get();
	}

	mirror::Class* GetType(bool resolve = true) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	uint32_t field_index = field_->GetDexFieldIndex();
	if (UNLIKELY(field_->GetDeclaringClass()->IsProxyClass())) {
	return Runtime::Current()->GetClassLinker()->FindSystemClass(Thread::Current(),
	field_->GetTypeDescriptor());
	}
	const DexFile* dex_file = field_->GetDexFile();
	const DexFile::FieldId& field_id = dex_file->GetFieldId(field_index);
	mirror::Class* type = field_->GetDexCache()->GetResolvedType(field_id.type_idx_);
	if (resolve && (type == nullptr)) {
	type = Runtime::Current()->GetClassLinker()->ResolveType(field_id.type_idx_, field_.Get());
	CHECK(type != nullptr \|\| Thread::Current()->IsExceptionPending());
	}
	return type;
	}

	// The returned const char* is only guaranteed to be valid for the lifetime of the FieldHelper.
	// If you need it longer, copy it into a std::string.
	const char* GetDeclaringClassDescriptor()
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	uint32_t field_index = field_->GetDexFieldIndex();
	if (UNLIKELY(field_->GetDeclaringClass()->IsProxyClass())) {
	DCHECK(field_->IsStatic());
	DCHECK_LT(field_index, 2U);
	// 0 == Class[] interfaces; 1 == Class[][] throws;
	declaring_class_descriptor_ = field_->GetDeclaringClass()->GetDescriptor();
	return declaring_class_descriptor_.c_str();
	}
	const DexFile* dex_file = field_->GetDexFile();
	const DexFile::FieldId& field_id = dex_file->GetFieldId(field_index);
	return dex_file->GetFieldDeclaringClassDescriptor(field_id);
	}

	private:
	Handle<mirror::ArtField> field_;
	std::string declaring_class_descriptor_;

	DISALLOW_COPY_AND_ASSIGN(FieldHelper);
	};

	class MethodHelper {
	public:
	explicit MethodHelper(Handle<mirror::ArtMethod> m) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
	: method_(m), shorty_(nullptr), shorty_len_(0) {
	SetMethod(m.Get());
	}

	void ChangeMethod(mirror::ArtMethod* new_m) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	DCHECK(new_m != nullptr);
	SetMethod(new_m);
	shorty_ = nullptr;
	}

	mirror::ArtMethod* GetMethod() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	return method_->GetInterfaceMethodIfProxy();
	}

	mirror::String* GetNameAsString(Thread* self) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	const DexFile* dex_file = method_->GetDexFile();
	mirror::ArtMethod* method = method_->GetInterfaceMethodIfProxy();
	uint32_t dex_method_idx = method->GetDexMethodIndex();
	const DexFile::MethodId& method_id = dex_file->GetMethodId(dex_method_idx);
	StackHandleScope<1> hs(self);
	Handle<mirror::DexCache> dex_cache(hs.NewHandle(method->GetDexCache()));
	return Runtime::Current()->GetClassLinker()->ResolveString(*dex_file, method_id.name_idx_,
	dex_cache);
	}

	const char* GetShorty() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	const char* result = shorty_;
	if (result == nullptr) {
	result = method_->GetShorty(&shorty_len_);
	shorty_ = result;
	}
	return result;
	}

	uint32_t GetShortyLength() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	if (shorty_ == nullptr) {
	GetShorty();
	}
	return shorty_len_;
	}

	// Counts the number of references in the parameter list of the corresponding method.
	// Note: Thus does _not_ include "this" for non-static methods.
	uint32_t GetNumberOfReferenceArgsWithoutReceiver() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	const char* shorty = GetShorty();
	uint32_t refs = 0;
	for (uint32_t i = 1; i < shorty_len_ ; ++i) {
	if (shorty[i] == 'L') {
	refs++;
	}
	}

	return refs;
	}

	// May cause thread suspension due to GetClassFromTypeIdx calling ResolveType this caused a large
	// number of bugs at call sites.
	mirror::Class* GetReturnType(bool resolve = true) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	mirror::ArtMethod* method = GetMethod();
	const DexFile* dex_file = method->GetDexFile();
	const DexFile::MethodId& method_id = dex_file->GetMethodId(method->GetDexMethodIndex());
	const DexFile::ProtoId& proto_id = dex_file->GetMethodPrototype(method_id);
	uint16_t return_type_idx = proto_id.return_type_idx_;
	return GetClassFromTypeIdx(return_type_idx, resolve);
	}

	size_t NumArgs() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	// "1 +" because the first in Args is the receiver.
	// "- 1" because we don't count the return type.
	return (method_->IsStatic() ? 0 : 1) + GetShortyLength() - 1;
	}

	// Get the primitive type associated with the given parameter.
	Primitive::Type GetParamPrimitiveType(size_t param) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	CHECK_LT(param, NumArgs());
	if (GetMethod()->IsStatic()) {
	param++; // 0th argument must skip return value at start of the shorty
	} else if (param == 0) {
	return Primitive::kPrimNot;
	}
	return Primitive::GetType(GetShorty()[param]);
	}

	// Is the specified parameter a long or double, where parameter 0 is 'this' for instance methods.
	bool IsParamALongOrDouble(size_t param) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	Primitive::Type type = GetParamPrimitiveType(param);
	return type == Primitive::kPrimLong \|\| type == Primitive::kPrimDouble;
	}

	// Is the specified parameter a reference, where parameter 0 is 'this' for instance methods.
	bool IsParamAReference(size_t param) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	return GetParamPrimitiveType(param) == Primitive::kPrimNot;
	}

	bool HasSameNameAndSignature(MethodHelper* other) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	const DexFile* dex_file = method_->GetDexFile();
	const DexFile::MethodId& mid = dex_file->GetMethodId(GetMethod()->GetDexMethodIndex());
	if (method_->GetDexCache() == other->method_->GetDexCache()) {
	const DexFile::MethodId& other_mid =
	dex_file->GetMethodId(other->GetMethod()->GetDexMethodIndex());
	return mid.name_idx_ == other_mid.name_idx_ && mid.proto_idx_ == other_mid.proto_idx_;
	}
	const DexFile* other_dex_file = other->method_->GetDexFile();
	const DexFile::MethodId& other_mid =
	other_dex_file->GetMethodId(other->GetMethod()->GetDexMethodIndex());
	if (!DexFileStringEquals(dex_file, mid.name_idx_, other_dex_file, other_mid.name_idx_)) {
	return false; // Name mismatch.
	}
	return dex_file->GetMethodSignature(mid) == other_dex_file->GetMethodSignature(other_mid);
	}

	bool HasSameSignatureWithDifferentClassLoaders(MethodHelper* other)
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	if (UNLIKELY(GetReturnType() != other->GetReturnType())) {
	return false;
	}
	const DexFile::TypeList* types = method_->GetParameterTypeList();
	const DexFile::TypeList* other_types = other->method_->GetParameterTypeList();
	if (types == nullptr) {
	return (other_types == nullptr) \|\| (other_types->Size() == 0);
	} else if (UNLIKELY(other_types == nullptr)) {
	return types->Size() == 0;
	}
	uint32_t num_types = types->Size();
	if (UNLIKELY(num_types != other_types->Size())) {
	return false;
	}
	for (uint32_t i = 0; i < num_types; ++i) {
	mirror::Class* param_type = GetClassFromTypeIdx(types->GetTypeItem(i).type_idx_);
	mirror::Class* other_param_type =
	other->GetClassFromTypeIdx(other_types->GetTypeItem(i).type_idx_);
	if (UNLIKELY(param_type != other_param_type)) {
	return false;
	}
	}
	return true;
	}

	mirror::Class* GetClassFromTypeIdx(uint16_t type_idx, bool resolve = true)
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	mirror::ArtMethod* method = GetMethod();
	mirror::Class* type = method->GetDexCacheResolvedTypes()->Get(type_idx);
	if (type == nullptr && resolve) {
	type = Runtime::Current()->GetClassLinker()->ResolveType(type_idx, method);
	CHECK(type != nullptr \|\| Thread::Current()->IsExceptionPending());
	}
	return type;
	}

	mirror::Class* GetDexCacheResolvedType(uint16_t type_idx)
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	return GetMethod()->GetDexCacheResolvedTypes()->Get(type_idx);
	}

	mirror::String* ResolveString(uint32_t string_idx) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	mirror::ArtMethod* method = GetMethod();
	mirror::String* s = method->GetDexCacheStrings()->Get(string_idx);
	if (UNLIKELY(s == nullptr)) {
	StackHandleScope<1> hs(Thread::Current());
	Handle<mirror::DexCache> dex_cache(hs.NewHandle(method->GetDexCache()));
	s = Runtime::Current()->GetClassLinker()->ResolveString(*method->GetDexFile(), string_idx,
	dex_cache);
	}
	return s;
	}

	uint32_t FindDexMethodIndexInOtherDexFile(const DexFile& other_dexfile)
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	mirror::ArtMethod* method = GetMethod();
	const DexFile* dexfile = method->GetDexFile();
	if (dexfile == &other_dexfile) {
	return method->GetDexMethodIndex();
	}
	const DexFile::MethodId& mid = dexfile->GetMethodId(method->GetDexMethodIndex());
	const char* mid_declaring_class_descriptor = dexfile->StringByTypeIdx(mid.class_idx_);
	const DexFile::StringId* other_descriptor =
	other_dexfile.FindStringId(mid_declaring_class_descriptor);
	if (other_descriptor != nullptr) {
	const DexFile::TypeId* other_type_id =
	other_dexfile.FindTypeId(other_dexfile.GetIndexForStringId(*other_descriptor));
	if (other_type_id != nullptr) {
	const char* mid_name = dexfile->GetMethodName(mid);
	const DexFile::StringId* other_name = other_dexfile.FindStringId(mid_name);
	if (other_name != nullptr) {
	uint16_t other_return_type_idx;
	std::vector<uint16_t> other_param_type_idxs;
	bool success = other_dexfile.CreateTypeList(
	dexfile->GetMethodSignature(mid).ToString(), &other_return_type_idx,
	&other_param_type_idxs);
	if (success) {
	const DexFile::ProtoId* other_sig =
	other_dexfile.FindProtoId(other_return_type_idx, other_param_type_idxs);
	if (other_sig != nullptr) {
	const DexFile::MethodId* other_mid = other_dexfile.FindMethodId(
	other_type_id, other_name, *other_sig);
	if (other_mid != nullptr) {
	return other_dexfile.GetIndexForMethodId(*other_mid);
	}
	}
	}
	}
	}
	}
	return DexFile::kDexNoIndex;
	}

	// The name_and_signature_idx MUST point to a MethodId with the same name and signature in the
	// other_dexfile, such as the method index used to resolve this method in the other_dexfile.
	uint32_t FindDexMethodIndexInOtherDexFile(const DexFile& other_dexfile,
	uint32_t name_and_signature_idx)
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	mirror::ArtMethod* method = GetMethod();
	const DexFile* dexfile = method->GetDexFile();
	const uint32_t dex_method_idx = method->GetDexMethodIndex();
	const DexFile::MethodId& mid = dexfile->GetMethodId(dex_method_idx);
	const DexFile::MethodId& name_and_sig_mid = other_dexfile.GetMethodId(name_and_signature_idx);
	DCHECK_STREQ(dexfile->GetMethodName(mid), other_dexfile.GetMethodName(name_and_sig_mid));
	DCHECK_EQ(dexfile->GetMethodSignature(mid), other_dexfile.GetMethodSignature(name_and_sig_mid));
	if (dexfile == &other_dexfile) {
	return dex_method_idx;
	}
	const char* mid_declaring_class_descriptor = dexfile->StringByTypeIdx(mid.class_idx_);
	const DexFile::StringId* other_descriptor =
	other_dexfile.FindStringId(mid_declaring_class_descriptor);
	if (other_descriptor != nullptr) {
	const DexFile::TypeId* other_type_id =
	other_dexfile.FindTypeId(other_dexfile.GetIndexForStringId(*other_descriptor));
	if (other_type_id != nullptr) {
	const DexFile::MethodId* other_mid = other_dexfile.FindMethodId(
	*other_type_id, other_dexfile.GetStringId(name_and_sig_mid.name_idx_),
	other_dexfile.GetProtoId(name_and_sig_mid.proto_idx_));
	if (other_mid != nullptr) {
	return other_dexfile.GetIndexForMethodId(*other_mid);
	}
	}
	}
	return DexFile::kDexNoIndex;
	}

	private:
	// Set the method_ field, for proxy methods looking up the interface method via the resolved
	// methods table.
	void SetMethod(mirror::ArtMethod* method) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	method_.Assign(method);
	}

	Handle<mirror::ArtMethod> method_;
	const char* shorty_;
	uint32_t shorty_len_;

	DISALLOW_COPY_AND_ASSIGN(MethodHelper);
	};

	} // namespace art

	#endif // ART_RUNTIME_OBJECT_UTILS_H_