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      1 /*
      2  * Copyright (C) 2014 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef ART_COMPILER_DEX_INLINE_METHOD_ANALYSER_H_
     18 #define ART_COMPILER_DEX_INLINE_METHOD_ANALYSER_H_
     19 
     20 #include "base/macros.h"
     21 #include "base/mutex.h"
     22 #include "dex_file.h"
     23 #include "dex_instruction.h"
     24 #include "method_reference.h"
     25 
     26 /*
     27  * NOTE: This code is part of the quick compiler. It lives in the runtime
     28  * only to allow the debugger to check whether a method has been inlined.
     29  */
     30 
     31 namespace art {
     32 
     33 namespace verifier {
     34 class MethodVerifier;
     35 }  // namespace verifier
     36 class ArtMethod;
     37 
     38 enum InlineMethodOpcode : uint16_t {
     39   kInlineOpNop,
     40   kInlineOpReturnArg,
     41   kInlineOpNonWideConst,
     42   kInlineOpIGet,
     43   kInlineOpIPut,
     44   kInlineOpConstructor,
     45 };
     46 
     47 struct InlineIGetIPutData {
     48   // The op_variant below is DexMemAccessType but the runtime doesn't know that enumeration.
     49   uint16_t op_variant : 3;
     50   uint16_t method_is_static : 1;
     51   uint16_t object_arg : 4;
     52   uint16_t src_arg : 4;  // iput only
     53   uint16_t return_arg_plus1 : 4;  // iput only, method argument to return + 1, 0 = return void.
     54   uint16_t field_idx;
     55   uint32_t is_volatile : 1;
     56   uint32_t field_offset : 31;
     57 };
     58 static_assert(sizeof(InlineIGetIPutData) == sizeof(uint64_t), "Invalid size of InlineIGetIPutData");
     59 
     60 struct InlineReturnArgData {
     61   uint16_t arg;
     62   uint16_t is_wide : 1;
     63   uint16_t is_object : 1;
     64   uint16_t reserved : 14;
     65   uint32_t reserved2;
     66 };
     67 static_assert(sizeof(InlineReturnArgData) == sizeof(uint64_t),
     68               "Invalid size of InlineReturnArgData");
     69 
     70 struct InlineConstructorData {
     71   // There can be up to 3 IPUTs, unused fields are marked with kNoDexIndex16.
     72   uint16_t iput0_field_index;
     73   uint16_t iput1_field_index;
     74   uint16_t iput2_field_index;
     75   uint16_t iput0_arg : 4;
     76   uint16_t iput1_arg : 4;
     77   uint16_t iput2_arg : 4;
     78   uint16_t reserved : 4;
     79 };
     80 static_assert(sizeof(InlineConstructorData) == sizeof(uint64_t),
     81               "Invalid size of InlineConstructorData");
     82 
     83 struct InlineMethod {
     84   InlineMethodOpcode opcode;
     85   union {
     86     uint64_t data;
     87     InlineIGetIPutData ifield_data;
     88     InlineReturnArgData return_data;
     89     InlineConstructorData constructor_data;
     90   } d;
     91 };
     92 
     93 class InlineMethodAnalyser {
     94  public:
     95   /**
     96    * Analyse method code to determine if the method is a candidate for inlining.
     97    * If it is, record the inlining data.
     98    *
     99    * @return true if the method is a candidate for inlining, false otherwise.
    100    */
    101   static bool AnalyseMethodCode(ArtMethod* method, InlineMethod* result)
    102       REQUIRES_SHARED(Locks::mutator_lock_);
    103 
    104   static constexpr bool IsInstructionIGet(Instruction::Code opcode) {
    105     return Instruction::IGET <= opcode && opcode <= Instruction::IGET_SHORT;
    106   }
    107 
    108   static constexpr bool IsInstructionIPut(Instruction::Code opcode) {
    109     return Instruction::IPUT <= opcode && opcode <= Instruction::IPUT_SHORT;
    110   }
    111 
    112   static constexpr uint16_t IGetVariant(Instruction::Code opcode) {
    113     return opcode - Instruction::IGET;
    114   }
    115 
    116   static constexpr uint16_t IPutVariant(Instruction::Code opcode) {
    117     return opcode - Instruction::IPUT;
    118   }
    119 
    120   // Determines whether the method is a synthetic accessor (method name starts with "access$").
    121   static bool IsSyntheticAccessor(MethodReference ref);
    122 
    123  private:
    124   static bool AnalyseMethodCode(const DexFile::CodeItem* code_item,
    125                                 const MethodReference& method_ref,
    126                                 bool is_static,
    127                                 ArtMethod* method,
    128                                 InlineMethod* result)
    129       REQUIRES_SHARED(Locks::mutator_lock_);
    130   static bool AnalyseReturnMethod(const DexFile::CodeItem* code_item, InlineMethod* result);
    131   static bool AnalyseConstMethod(const DexFile::CodeItem* code_item, InlineMethod* result);
    132   static bool AnalyseIGetMethod(const DexFile::CodeItem* code_item,
    133                                 const MethodReference& method_ref,
    134                                 bool is_static,
    135                                 ArtMethod* method,
    136                                 InlineMethod* result)
    137       REQUIRES_SHARED(Locks::mutator_lock_);
    138   static bool AnalyseIPutMethod(const DexFile::CodeItem* code_item,
    139                                 const MethodReference& method_ref,
    140                                 bool is_static,
    141                                 ArtMethod* method,
    142                                 InlineMethod* result)
    143       REQUIRES_SHARED(Locks::mutator_lock_);
    144 
    145   // Can we fast path instance field access in a verified accessor?
    146   // If yes, computes field's offset and volatility and whether the method is static or not.
    147   static bool ComputeSpecialAccessorInfo(ArtMethod* method,
    148                                          uint32_t field_idx,
    149                                          bool is_put,
    150                                          InlineIGetIPutData* result)
    151       REQUIRES_SHARED(Locks::mutator_lock_);
    152 };
    153 
    154 }  // namespace art
    155 
    156 #endif  // ART_COMPILER_DEX_INLINE_METHOD_ANALYSER_H_
    157