runtime/quick/inline_method_analyser.cc - LeafOS-Project/android_art - Gitiles

 /*
  * Copyright (C) 2014 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.
  */

 #include "inline_method_analyser.h"
 #include "dex_file-inl.h"
 #include "dex_instruction.h"
 #include "dex_instruction-inl.h"
 #include "mirror/art_field.h"
 #include "mirror/art_field-inl.h"
 #include "mirror/art_method.h"
 #include "mirror/art_method-inl.h"
 #include "mirror/class.h"
 #include "mirror/class-inl.h"
 #include "mirror/dex_cache.h"
 #include "mirror/dex_cache-inl.h"
 #include "verifier/method_verifier.h"
 #include "verifier/method_verifier-inl.h"

 /*
  * NOTE: This code is part of the quick compiler. It lives in the runtime
  * only to allow the debugger to check whether a method has been inlined.
  */

 namespace art {

 static_assert(InlineMethodAnalyser::IsInstructionIGet(Instruction::IGET), "iget type");
 static_assert(InlineMethodAnalyser::IsInstructionIGet(Instruction::IGET_WIDE), "iget_wide type");
 static_assert(InlineMethodAnalyser::IsInstructionIGet(Instruction::IGET_OBJECT),
               "iget_object type");
 static_assert(InlineMethodAnalyser::IsInstructionIGet(Instruction::IGET_BOOLEAN),
               "iget_boolean type");
 static_assert(InlineMethodAnalyser::IsInstructionIGet(Instruction::IGET_BYTE), "iget_byte type");
 static_assert(InlineMethodAnalyser::IsInstructionIGet(Instruction::IGET_CHAR), "iget_char type");
 static_assert(InlineMethodAnalyser::IsInstructionIGet(Instruction::IGET_SHORT), "iget_short type");
 static_assert(InlineMethodAnalyser::IsInstructionIPut(Instruction::IPUT), "iput type");
 static_assert(InlineMethodAnalyser::IsInstructionIPut(Instruction::IPUT_WIDE), "iput_wide type");
 static_assert(InlineMethodAnalyser::IsInstructionIPut(Instruction::IPUT_OBJECT),
               "iput_object type");
 static_assert(InlineMethodAnalyser::IsInstructionIPut(Instruction::IPUT_BOOLEAN),
               "iput_boolean type");
 static_assert(InlineMethodAnalyser::IsInstructionIPut(Instruction::IPUT_BYTE), "iput_byte type");
 static_assert(InlineMethodAnalyser::IsInstructionIPut(Instruction::IPUT_CHAR), "iput_char type");
 static_assert(InlineMethodAnalyser::IsInstructionIPut(Instruction::IPUT_SHORT), "iput_short type");
 static_assert(InlineMethodAnalyser::IGetVariant(Instruction::IGET) ==
     InlineMethodAnalyser::IPutVariant(Instruction::IPUT), "iget/iput variant");
 static_assert(InlineMethodAnalyser::IGetVariant(Instruction::IGET_WIDE) ==
     InlineMethodAnalyser::IPutVariant(Instruction::IPUT_WIDE), "iget/iput_wide variant");
 static_assert(InlineMethodAnalyser::IGetVariant(Instruction::IGET_OBJECT) ==
     InlineMethodAnalyser::IPutVariant(Instruction::IPUT_OBJECT), "iget/iput_object variant");
 static_assert(InlineMethodAnalyser::IGetVariant(Instruction::IGET_BOOLEAN) ==
     InlineMethodAnalyser::IPutVariant(Instruction::IPUT_BOOLEAN), "iget/iput_boolean variant");
 static_assert(InlineMethodAnalyser::IGetVariant(Instruction::IGET_BYTE) ==
     InlineMethodAnalyser::IPutVariant(Instruction::IPUT_BYTE), "iget/iput_byte variant");
 static_assert(InlineMethodAnalyser::IGetVariant(Instruction::IGET_CHAR) ==
     InlineMethodAnalyser::IPutVariant(Instruction::IPUT_CHAR), "iget/iput_char variant");
 static_assert(InlineMethodAnalyser::IGetVariant(Instruction::IGET_SHORT) ==
     InlineMethodAnalyser::IPutVariant(Instruction::IPUT_SHORT), "iget/iput_short variant");

 // This is used by compiler and debugger. We look into the dex cache for resolved methods and
 // fields. However, in the context of the debugger, not all methods and fields are resolved. Since
 // we need to be able to detect possibly inlined method, we pass a null inline method to indicate
 // we don't want to take unresolved methods and fields into account during analysis.
 bool InlineMethodAnalyser::AnalyseMethodCode(verifier::MethodVerifier* verifier,
                                              InlineMethod* method) {
   DCHECK(verifier != nullptr);
   DCHECK_EQ(Runtime::Current()->IsCompiler(), method != nullptr);
   if (!Runtime::Current()->UseJit()) {
     DCHECK_EQ(verifier->CanLoadClasses(), method != nullptr);
   }
   // We currently support only plain return or 2-instruction methods.

   const DexFile::CodeItem* code_item = verifier->CodeItem();
   DCHECK_NE(code_item->insns_size_in_code_units_, 0u);
   const Instruction* instruction = Instruction::At(code_item->insns_);
   Instruction::Code opcode = instruction->Opcode();

   switch (opcode) {
     case Instruction::RETURN_VOID:
       if (method != nullptr) {
         method->opcode = kInlineOpNop;
         method->flags = kInlineSpecial;
         method->d.data = 0u;
       }
       return true;
     case Instruction::RETURN:
     case Instruction::RETURN_OBJECT:
     case Instruction::RETURN_WIDE:
       return AnalyseReturnMethod(code_item, method);
     case Instruction::CONST:
     case Instruction::CONST_4:
     case Instruction::CONST_16:
     case Instruction::CONST_HIGH16:
       // TODO: Support wide constants (RETURN_WIDE).
       return AnalyseConstMethod(code_item, method);
     case Instruction::IGET:
     case Instruction::IGET_OBJECT:
     case Instruction::IGET_BOOLEAN:
     case Instruction::IGET_BYTE:
     case Instruction::IGET_CHAR:
     case Instruction::IGET_SHORT:
     case Instruction::IGET_WIDE:
     // TODO: Add handling for JIT.
     // case Instruction::IGET_QUICK:
     // case Instruction::IGET_WIDE_QUICK:
     // case Instruction::IGET_OBJECT_QUICK:
       return AnalyseIGetMethod(verifier, method);
     case Instruction::IPUT:
     case Instruction::IPUT_OBJECT:
     case Instruction::IPUT_BOOLEAN:
     case Instruction::IPUT_BYTE:
     case Instruction::IPUT_CHAR:
     case Instruction::IPUT_SHORT:
     case Instruction::IPUT_WIDE:
       // TODO: Add handling for JIT.
     // case Instruction::IPUT_QUICK:
     // case Instruction::IPUT_WIDE_QUICK:
     // case Instruction::IPUT_OBJECT_QUICK:
       return AnalyseIPutMethod(verifier, method);
     default:
       return false;
   }
 }

 bool InlineMethodAnalyser::IsSyntheticAccessor(MethodReference ref) {
   const DexFile::MethodId& method_id = ref.dex_file->GetMethodId(ref.dex_method_index);
   const char* method_name = ref.dex_file->GetMethodName(method_id);
   return strncmp(method_name, "access$", strlen("access$")) == 0;
 }

 bool InlineMethodAnalyser::AnalyseReturnMethod(const DexFile::CodeItem* code_item,
                                                InlineMethod* result) {
   const Instruction* return_instruction = Instruction::At(code_item->insns_);
   Instruction::Code return_opcode = return_instruction->Opcode();
   uint32_t reg = return_instruction->VRegA_11x();
   uint32_t arg_start = code_item->registers_size_ - code_item->ins_size_;
   DCHECK_GE(reg, arg_start);
   DCHECK_LT((return_opcode == Instruction::RETURN_WIDE) ? reg + 1 : reg,
       code_item->registers_size_);

   if (result != nullptr) {
     result->opcode = kInlineOpReturnArg;
     result->flags = kInlineSpecial;
     InlineReturnArgData* data = &result->d.return_data;
     data->arg = reg - arg_start;
     data->is_wide = (return_opcode == Instruction::RETURN_WIDE) ? 1u : 0u;
     data->is_object = (return_opcode == Instruction::RETURN_OBJECT) ? 1u : 0u;
     data->reserved = 0u;
     data->reserved2 = 0u;
   }
   return true;
 }

 bool InlineMethodAnalyser::AnalyseConstMethod(const DexFile::CodeItem* code_item,
                                               InlineMethod* result) {
   const Instruction* instruction = Instruction::At(code_item->insns_);
   const Instruction* return_instruction = instruction->Next();
   Instruction::Code return_opcode = return_instruction->Opcode();
   if (return_opcode != Instruction::RETURN &&
       return_opcode != Instruction::RETURN_OBJECT) {
     return false;
   }

   int32_t return_reg = return_instruction->VRegA_11x();
   DCHECK_LT(return_reg, code_item->registers_size_);

   int32_t const_value = instruction->VRegB();
   if (instruction->Opcode() == Instruction::CONST_HIGH16) {
     const_value <<= 16;
   }
   DCHECK_LT(instruction->VRegA(), code_item->registers_size_);
   if (instruction->VRegA() != return_reg) {
     return false;  // Not returning the value set by const?
   }
   if (return_opcode == Instruction::RETURN_OBJECT && const_value != 0) {
     return false;  // Returning non-null reference constant?
   }
   if (result != nullptr) {
     result->opcode = kInlineOpNonWideConst;
     result->flags = kInlineSpecial;
     result->d.data = static_cast<uint64_t>(const_value);
   }
   return true;
 }

 bool InlineMethodAnalyser::AnalyseIGetMethod(verifier::MethodVerifier* verifier,
                                              InlineMethod* result) {
   const DexFile::CodeItem* code_item = verifier->CodeItem();
   const Instruction* instruction = Instruction::At(code_item->insns_);
   Instruction::Code opcode = instruction->Opcode();
   DCHECK(IsInstructionIGet(opcode));

   const Instruction* return_instruction = instruction->Next();
   Instruction::Code return_opcode = return_instruction->Opcode();
   if (!(return_opcode == Instruction::RETURN_WIDE && opcode == Instruction::IGET_WIDE) &&
       !(return_opcode == Instruction::RETURN_OBJECT && opcode == Instruction::IGET_OBJECT) &&
       !(return_opcode == Instruction::RETURN && opcode != Instruction::IGET_WIDE &&
           opcode != Instruction::IGET_OBJECT)) {
     return false;
   }

   uint32_t return_reg = return_instruction->VRegA_11x();
   DCHECK_LT(return_opcode == Instruction::RETURN_WIDE ? return_reg + 1 : return_reg,
             code_item->registers_size_);

   uint32_t dst_reg = instruction->VRegA_22c();
   uint32_t object_reg = instruction->VRegB_22c();
   uint32_t field_idx = instruction->VRegC_22c();
   uint32_t arg_start = code_item->registers_size_ - code_item->ins_size_;
   DCHECK_GE(object_reg, arg_start);
   DCHECK_LT(object_reg, code_item->registers_size_);
   uint32_t object_arg = object_reg - arg_start;

   DCHECK_LT(opcode == Instruction::IGET_WIDE ? dst_reg + 1 : dst_reg, code_item->registers_size_);
   if (dst_reg != return_reg) {
     return false;  // Not returning the value retrieved by IGET?
   }

   if ((verifier->GetAccessFlags() & kAccStatic) != 0u || object_arg != 0u) {
     // TODO: Implement inlining of IGET on non-"this" registers (needs correct stack trace for NPE).
     // Allow synthetic accessors. We don't care about losing their stack frame in NPE.
     if (!IsSyntheticAccessor(verifier->GetMethodReference())) {
       return false;
     }
   }

   // InlineIGetIPutData::object_arg is only 4 bits wide.
   static constexpr uint16_t kMaxObjectArg = 15u;
   if (object_arg > kMaxObjectArg) {
     return false;
   }

   if (result != nullptr) {
     InlineIGetIPutData* data = &result->d.ifield_data;
     if (!ComputeSpecialAccessorInfo(field_idx, false, verifier, data)) {
       return false;
     }
     result->opcode = kInlineOpIGet;
     result->flags = kInlineSpecial;
     data->op_variant = IGetVariant(opcode);
     data->method_is_static = (verifier->GetAccessFlags() & kAccStatic) != 0u ? 1u : 0u;
     data->object_arg = object_arg;  // Allow IGET on any register, not just "this".
     data->src_arg = 0u;
     data->return_arg_plus1 = 0u;
   }
   return true;
 }

 bool InlineMethodAnalyser::AnalyseIPutMethod(verifier::MethodVerifier* verifier,
                                              InlineMethod* result) {
   const DexFile::CodeItem* code_item = verifier->CodeItem();
   const Instruction* instruction = Instruction::At(code_item->insns_);
   Instruction::Code opcode = instruction->Opcode();
   DCHECK(IsInstructionIPut(opcode));

   const Instruction* return_instruction = instruction->Next();
   Instruction::Code return_opcode = return_instruction->Opcode();
   uint32_t arg_start = code_item->registers_size_ - code_item->ins_size_;
   uint16_t return_arg_plus1 = 0u;
   if (return_opcode != Instruction::RETURN_VOID) {
     if (return_opcode != Instruction::RETURN &&
         return_opcode != Instruction::RETURN_OBJECT &&
         return_opcode != Instruction::RETURN_WIDE) {
       return false;
     }
     // Returning an argument.
     uint32_t return_reg = return_instruction->VRegA_11x();
     DCHECK_GE(return_reg, arg_start);
     DCHECK_LT(return_opcode == Instruction::RETURN_WIDE ? return_reg + 1u : return_reg,
               code_item->registers_size_);
     return_arg_plus1 = return_reg - arg_start + 1u;
   }

   uint32_t src_reg = instruction->VRegA_22c();
   uint32_t object_reg = instruction->VRegB_22c();
   uint32_t field_idx = instruction->VRegC_22c();
   DCHECK_GE(object_reg, arg_start);
   DCHECK_LT(object_reg, code_item->registers_size_);
   DCHECK_GE(src_reg, arg_start);
   DCHECK_LT(opcode == Instruction::IPUT_WIDE ? src_reg + 1 : src_reg, code_item->registers_size_);
   uint32_t object_arg = object_reg - arg_start;
   uint32_t src_arg = src_reg - arg_start;

   if ((verifier->GetAccessFlags() & kAccStatic) != 0u || object_arg != 0u) {
     // TODO: Implement inlining of IPUT on non-"this" registers (needs correct stack trace for NPE).
     // Allow synthetic accessors. We don't care about losing their stack frame in NPE.
     if (!IsSyntheticAccessor(verifier->GetMethodReference())) {
       return false;
     }
   }

   // InlineIGetIPutData::object_arg/src_arg/return_arg_plus1 are each only 4 bits wide.
   static constexpr uint16_t kMaxObjectArg = 15u;
   static constexpr uint16_t kMaxSrcArg = 15u;
   static constexpr uint16_t kMaxReturnArgPlus1 = 15u;
   if (object_arg > kMaxObjectArg || src_arg > kMaxSrcArg || return_arg_plus1 > kMaxReturnArgPlus1) {
     return false;
   }

   if (result != nullptr) {
     InlineIGetIPutData* data = &result->d.ifield_data;
     if (!ComputeSpecialAccessorInfo(field_idx, true, verifier, data)) {
       return false;
     }
     result->opcode = kInlineOpIPut;
     result->flags = kInlineSpecial;
     data->op_variant = IPutVariant(opcode);
     data->method_is_static = (verifier->GetAccessFlags() & kAccStatic) != 0u ? 1u : 0u;
     data->object_arg = object_arg;  // Allow IPUT on any register, not just "this".
     data->src_arg = src_arg;
     data->return_arg_plus1 = return_arg_plus1;
   }
   return true;
 }

 bool InlineMethodAnalyser::ComputeSpecialAccessorInfo(uint32_t field_idx, bool is_put,
                                                       verifier::MethodVerifier* verifier,
                                                       InlineIGetIPutData* result) {
   mirror::DexCache* dex_cache = verifier->GetDexCache();
   uint32_t method_idx = verifier->GetMethodReference().dex_method_index;
   mirror::ArtMethod* method = dex_cache->GetResolvedMethod(method_idx);
   mirror::ArtField* field = dex_cache->GetResolvedField(field_idx);
   if (method == nullptr || field == nullptr || field->IsStatic()) {
     return false;
   }
   mirror::Class* method_class = method->GetDeclaringClass();
   mirror::Class* field_class = field->GetDeclaringClass();
   if (!method_class->CanAccessResolvedField(field_class, field, dex_cache, field_idx) ||
       (is_put && field->IsFinal() && method_class != field_class)) {
     return false;
   }
   DCHECK_GE(field->GetOffset().Int32Value(), 0);
   result->field_idx = field_idx;
   result->field_offset = field->GetOffset().Int32Value();
   result->is_volatile = field->IsVolatile();
   return true;
 }

 }  // namespace art
	/*
	* Copyright (C) 2014 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.
	*/

	#include "inline_method_analyser.h"
	#include "dex_file-inl.h"
	#include "dex_instruction.h"
	#include "dex_instruction-inl.h"
	#include "mirror/art_field.h"
	#include "mirror/art_field-inl.h"
	#include "mirror/art_method.h"
	#include "mirror/art_method-inl.h"
	#include "mirror/class.h"
	#include "mirror/class-inl.h"
	#include "mirror/dex_cache.h"
	#include "mirror/dex_cache-inl.h"
	#include "verifier/method_verifier.h"
	#include "verifier/method_verifier-inl.h"

	/*
	* NOTE: This code is part of the quick compiler. It lives in the runtime
	* only to allow the debugger to check whether a method has been inlined.
	*/

	namespace art {

	static_assert(InlineMethodAnalyser::IsInstructionIGet(Instruction::IGET), "iget type");
	static_assert(InlineMethodAnalyser::IsInstructionIGet(Instruction::IGET_WIDE), "iget_wide type");
	static_assert(InlineMethodAnalyser::IsInstructionIGet(Instruction::IGET_OBJECT),
	"iget_object type");
	static_assert(InlineMethodAnalyser::IsInstructionIGet(Instruction::IGET_BOOLEAN),
	"iget_boolean type");
	static_assert(InlineMethodAnalyser::IsInstructionIGet(Instruction::IGET_BYTE), "iget_byte type");
	static_assert(InlineMethodAnalyser::IsInstructionIGet(Instruction::IGET_CHAR), "iget_char type");
	static_assert(InlineMethodAnalyser::IsInstructionIGet(Instruction::IGET_SHORT), "iget_short type");
	static_assert(InlineMethodAnalyser::IsInstructionIPut(Instruction::IPUT), "iput type");
	static_assert(InlineMethodAnalyser::IsInstructionIPut(Instruction::IPUT_WIDE), "iput_wide type");
	static_assert(InlineMethodAnalyser::IsInstructionIPut(Instruction::IPUT_OBJECT),
	"iput_object type");
	static_assert(InlineMethodAnalyser::IsInstructionIPut(Instruction::IPUT_BOOLEAN),
	"iput_boolean type");
	static_assert(InlineMethodAnalyser::IsInstructionIPut(Instruction::IPUT_BYTE), "iput_byte type");
	static_assert(InlineMethodAnalyser::IsInstructionIPut(Instruction::IPUT_CHAR), "iput_char type");
	static_assert(InlineMethodAnalyser::IsInstructionIPut(Instruction::IPUT_SHORT), "iput_short type");
	static_assert(InlineMethodAnalyser::IGetVariant(Instruction::IGET) ==
	InlineMethodAnalyser::IPutVariant(Instruction::IPUT), "iget/iput variant");
	static_assert(InlineMethodAnalyser::IGetVariant(Instruction::IGET_WIDE) ==
	InlineMethodAnalyser::IPutVariant(Instruction::IPUT_WIDE), "iget/iput_wide variant");
	static_assert(InlineMethodAnalyser::IGetVariant(Instruction::IGET_OBJECT) ==
	InlineMethodAnalyser::IPutVariant(Instruction::IPUT_OBJECT), "iget/iput_object variant");
	static_assert(InlineMethodAnalyser::IGetVariant(Instruction::IGET_BOOLEAN) ==
	InlineMethodAnalyser::IPutVariant(Instruction::IPUT_BOOLEAN), "iget/iput_boolean variant");
	static_assert(InlineMethodAnalyser::IGetVariant(Instruction::IGET_BYTE) ==
	InlineMethodAnalyser::IPutVariant(Instruction::IPUT_BYTE), "iget/iput_byte variant");
	static_assert(InlineMethodAnalyser::IGetVariant(Instruction::IGET_CHAR) ==
	InlineMethodAnalyser::IPutVariant(Instruction::IPUT_CHAR), "iget/iput_char variant");
	static_assert(InlineMethodAnalyser::IGetVariant(Instruction::IGET_SHORT) ==
	InlineMethodAnalyser::IPutVariant(Instruction::IPUT_SHORT), "iget/iput_short variant");

	// This is used by compiler and debugger. We look into the dex cache for resolved methods and
	// fields. However, in the context of the debugger, not all methods and fields are resolved. Since
	// we need to be able to detect possibly inlined method, we pass a null inline method to indicate
	// we don't want to take unresolved methods and fields into account during analysis.
	bool InlineMethodAnalyser::AnalyseMethodCode(verifier::MethodVerifier* verifier,
	InlineMethod* method) {
	DCHECK(verifier != nullptr);
	DCHECK_EQ(Runtime::Current()->IsCompiler(), method != nullptr);
	if (!Runtime::Current()->UseJit()) {
	DCHECK_EQ(verifier->CanLoadClasses(), method != nullptr);
	}
	// We currently support only plain return or 2-instruction methods.

	const DexFile::CodeItem* code_item = verifier->CodeItem();
	DCHECK_NE(code_item->insns_size_in_code_units_, 0u);
	const Instruction* instruction = Instruction::At(code_item->insns_);
	Instruction::Code opcode = instruction->Opcode();

	switch (opcode) {
	case Instruction::RETURN_VOID:
	if (method != nullptr) {
	method->opcode = kInlineOpNop;
	method->flags = kInlineSpecial;
	method->d.data = 0u;
	}
	return true;
	case Instruction::RETURN:
	case Instruction::RETURN_OBJECT:
	case Instruction::RETURN_WIDE:
	return AnalyseReturnMethod(code_item, method);
	case Instruction::CONST:
	case Instruction::CONST_4:
	case Instruction::CONST_16:
	case Instruction::CONST_HIGH16:
	// TODO: Support wide constants (RETURN_WIDE).
	return AnalyseConstMethod(code_item, method);
	case Instruction::IGET:
	case Instruction::IGET_OBJECT:
	case Instruction::IGET_BOOLEAN:
	case Instruction::IGET_BYTE:
	case Instruction::IGET_CHAR:
	case Instruction::IGET_SHORT:
	case Instruction::IGET_WIDE:
	// TODO: Add handling for JIT.
	// case Instruction::IGET_QUICK:
	// case Instruction::IGET_WIDE_QUICK:
	// case Instruction::IGET_OBJECT_QUICK:
	return AnalyseIGetMethod(verifier, method);
	case Instruction::IPUT:
	case Instruction::IPUT_OBJECT:
	case Instruction::IPUT_BOOLEAN:
	case Instruction::IPUT_BYTE:
	case Instruction::IPUT_CHAR:
	case Instruction::IPUT_SHORT:
	case Instruction::IPUT_WIDE:
	// TODO: Add handling for JIT.
	// case Instruction::IPUT_QUICK:
	// case Instruction::IPUT_WIDE_QUICK:
	// case Instruction::IPUT_OBJECT_QUICK:
	return AnalyseIPutMethod(verifier, method);
	default:
	return false;
	}
	}

	bool InlineMethodAnalyser::IsSyntheticAccessor(MethodReference ref) {
	const DexFile::MethodId& method_id = ref.dex_file->GetMethodId(ref.dex_method_index);
	const char* method_name = ref.dex_file->GetMethodName(method_id);
	return strncmp(method_name, "access$", strlen("access$")) == 0;
	}

	bool InlineMethodAnalyser::AnalyseReturnMethod(const DexFile::CodeItem* code_item,
	InlineMethod* result) {
	const Instruction* return_instruction = Instruction::At(code_item->insns_);
	Instruction::Code return_opcode = return_instruction->Opcode();
	uint32_t reg = return_instruction->VRegA_11x();
	uint32_t arg_start = code_item->registers_size_ - code_item->ins_size_;
	DCHECK_GE(reg, arg_start);
	DCHECK_LT((return_opcode == Instruction::RETURN_WIDE) ? reg + 1 : reg,
	code_item->registers_size_);

	if (result != nullptr) {
	result->opcode = kInlineOpReturnArg;
	result->flags = kInlineSpecial;
	InlineReturnArgData* data = &result->d.return_data;
	data->arg = reg - arg_start;
	data->is_wide = (return_opcode == Instruction::RETURN_WIDE) ? 1u : 0u;
	data->is_object = (return_opcode == Instruction::RETURN_OBJECT) ? 1u : 0u;
	data->reserved = 0u;
	data->reserved2 = 0u;
	}
	return true;
	}

	bool InlineMethodAnalyser::AnalyseConstMethod(const DexFile::CodeItem* code_item,
	InlineMethod* result) {
	const Instruction* instruction = Instruction::At(code_item->insns_);
	const Instruction* return_instruction = instruction->Next();
	Instruction::Code return_opcode = return_instruction->Opcode();
	if (return_opcode != Instruction::RETURN &&
	return_opcode != Instruction::RETURN_OBJECT) {
	return false;
	}

	int32_t return_reg = return_instruction->VRegA_11x();
	DCHECK_LT(return_reg, code_item->registers_size_);

	int32_t const_value = instruction->VRegB();
	if (instruction->Opcode() == Instruction::CONST_HIGH16) {
	const_value <<= 16;
	}
	DCHECK_LT(instruction->VRegA(), code_item->registers_size_);
	if (instruction->VRegA() != return_reg) {
	return false; // Not returning the value set by const?
	}
	if (return_opcode == Instruction::RETURN_OBJECT && const_value != 0) {
	return false; // Returning non-null reference constant?
	}
	if (result != nullptr) {
	result->opcode = kInlineOpNonWideConst;
	result->flags = kInlineSpecial;
	result->d.data = static_cast<uint64_t>(const_value);
	}
	return true;
	}

	bool InlineMethodAnalyser::AnalyseIGetMethod(verifier::MethodVerifier* verifier,
	InlineMethod* result) {
	const DexFile::CodeItem* code_item = verifier->CodeItem();
	const Instruction* instruction = Instruction::At(code_item->insns_);
	Instruction::Code opcode = instruction->Opcode();
	DCHECK(IsInstructionIGet(opcode));

	const Instruction* return_instruction = instruction->Next();
	Instruction::Code return_opcode = return_instruction->Opcode();
	if (!(return_opcode == Instruction::RETURN_WIDE && opcode == Instruction::IGET_WIDE) &&
	!(return_opcode == Instruction::RETURN_OBJECT && opcode == Instruction::IGET_OBJECT) &&
	!(return_opcode == Instruction::RETURN && opcode != Instruction::IGET_WIDE &&
	opcode != Instruction::IGET_OBJECT)) {
	return false;
	}

	uint32_t return_reg = return_instruction->VRegA_11x();
	DCHECK_LT(return_opcode == Instruction::RETURN_WIDE ? return_reg + 1 : return_reg,
	code_item->registers_size_);

	uint32_t dst_reg = instruction->VRegA_22c();
	uint32_t object_reg = instruction->VRegB_22c();
	uint32_t field_idx = instruction->VRegC_22c();
	uint32_t arg_start = code_item->registers_size_ - code_item->ins_size_;
	DCHECK_GE(object_reg, arg_start);
	DCHECK_LT(object_reg, code_item->registers_size_);
	uint32_t object_arg = object_reg - arg_start;

	DCHECK_LT(opcode == Instruction::IGET_WIDE ? dst_reg + 1 : dst_reg, code_item->registers_size_);
	if (dst_reg != return_reg) {
	return false; // Not returning the value retrieved by IGET?
	}

	if ((verifier->GetAccessFlags() & kAccStatic) != 0u \|\| object_arg != 0u) {
	// TODO: Implement inlining of IGET on non-"this" registers (needs correct stack trace for NPE).
	// Allow synthetic accessors. We don't care about losing their stack frame in NPE.
	if (!IsSyntheticAccessor(verifier->GetMethodReference())) {
	return false;
	}
	}

	// InlineIGetIPutData::object_arg is only 4 bits wide.
	static constexpr uint16_t kMaxObjectArg = 15u;
	if (object_arg > kMaxObjectArg) {
	return false;
	}

	if (result != nullptr) {
	InlineIGetIPutData* data = &result->d.ifield_data;
	if (!ComputeSpecialAccessorInfo(field_idx, false, verifier, data)) {
	return false;
	}
	result->opcode = kInlineOpIGet;
	result->flags = kInlineSpecial;
	data->op_variant = IGetVariant(opcode);
	data->method_is_static = (verifier->GetAccessFlags() & kAccStatic) != 0u ? 1u : 0u;
	data->object_arg = object_arg; // Allow IGET on any register, not just "this".
	data->src_arg = 0u;
	data->return_arg_plus1 = 0u;
	}
	return true;
	}

	bool InlineMethodAnalyser::AnalyseIPutMethod(verifier::MethodVerifier* verifier,
	InlineMethod* result) {
	const DexFile::CodeItem* code_item = verifier->CodeItem();
	const Instruction* instruction = Instruction::At(code_item->insns_);
	Instruction::Code opcode = instruction->Opcode();
	DCHECK(IsInstructionIPut(opcode));

	const Instruction* return_instruction = instruction->Next();
	Instruction::Code return_opcode = return_instruction->Opcode();
	uint32_t arg_start = code_item->registers_size_ - code_item->ins_size_;
	uint16_t return_arg_plus1 = 0u;
	if (return_opcode != Instruction::RETURN_VOID) {
	if (return_opcode != Instruction::RETURN &&
	return_opcode != Instruction::RETURN_OBJECT &&
	return_opcode != Instruction::RETURN_WIDE) {
	return false;
	}
	// Returning an argument.
	uint32_t return_reg = return_instruction->VRegA_11x();
	DCHECK_GE(return_reg, arg_start);
	DCHECK_LT(return_opcode == Instruction::RETURN_WIDE ? return_reg + 1u : return_reg,
	code_item->registers_size_);
	return_arg_plus1 = return_reg - arg_start + 1u;
	}

	uint32_t src_reg = instruction->VRegA_22c();
	uint32_t object_reg = instruction->VRegB_22c();
	uint32_t field_idx = instruction->VRegC_22c();
	DCHECK_GE(object_reg, arg_start);
	DCHECK_LT(object_reg, code_item->registers_size_);
	DCHECK_GE(src_reg, arg_start);
	DCHECK_LT(opcode == Instruction::IPUT_WIDE ? src_reg + 1 : src_reg, code_item->registers_size_);
	uint32_t object_arg = object_reg - arg_start;
	uint32_t src_arg = src_reg - arg_start;

	if ((verifier->GetAccessFlags() & kAccStatic) != 0u \|\| object_arg != 0u) {
	// TODO: Implement inlining of IPUT on non-"this" registers (needs correct stack trace for NPE).
	// Allow synthetic accessors. We don't care about losing their stack frame in NPE.
	if (!IsSyntheticAccessor(verifier->GetMethodReference())) {
	return false;
	}
	}

	// InlineIGetIPutData::object_arg/src_arg/return_arg_plus1 are each only 4 bits wide.
	static constexpr uint16_t kMaxObjectArg = 15u;
	static constexpr uint16_t kMaxSrcArg = 15u;
	static constexpr uint16_t kMaxReturnArgPlus1 = 15u;
	if (object_arg > kMaxObjectArg \|\| src_arg > kMaxSrcArg \|\| return_arg_plus1 > kMaxReturnArgPlus1) {
	return false;
	}

	if (result != nullptr) {
	InlineIGetIPutData* data = &result->d.ifield_data;
	if (!ComputeSpecialAccessorInfo(field_idx, true, verifier, data)) {
	return false;
	}
	result->opcode = kInlineOpIPut;
	result->flags = kInlineSpecial;
	data->op_variant = IPutVariant(opcode);
	data->method_is_static = (verifier->GetAccessFlags() & kAccStatic) != 0u ? 1u : 0u;
	data->object_arg = object_arg; // Allow IPUT on any register, not just "this".
	data->src_arg = src_arg;
	data->return_arg_plus1 = return_arg_plus1;
	}
	return true;
	}

	bool InlineMethodAnalyser::ComputeSpecialAccessorInfo(uint32_t field_idx, bool is_put,
	verifier::MethodVerifier* verifier,
	InlineIGetIPutData* result) {
	mirror::DexCache* dex_cache = verifier->GetDexCache();
	uint32_t method_idx = verifier->GetMethodReference().dex_method_index;
	mirror::ArtMethod* method = dex_cache->GetResolvedMethod(method_idx);
	mirror::ArtField* field = dex_cache->GetResolvedField(field_idx);
	if (method == nullptr \|\| field == nullptr \|\| field->IsStatic()) {
	return false;
	}
	mirror::Class* method_class = method->GetDeclaringClass();
	mirror::Class* field_class = field->GetDeclaringClass();
	if (!method_class->CanAccessResolvedField(field_class, field, dex_cache, field_idx) \|\|
	(is_put && field->IsFinal() && method_class != field_class)) {
	return false;
	}
	DCHECK_GE(field->GetOffset().Int32Value(), 0);
	result->field_idx = field_idx;
	result->field_offset = field->GetOffset().Int32Value();
	result->is_volatile = field->IsVolatile();
	return true;
	}

	} // namespace art