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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_PASS_H_
     18 #define ART_COMPILER_DEX_PASS_H_
     19 
     20 #include <string>
     21 
     22 #include "base/macros.h"
     23 namespace art {
     24 
     25 // Forward declarations.
     26 struct BasicBlock;
     27 struct CompilationUnit;
     28 class Pass;
     29 
     30 // Empty Pass Data Class, can be extended by any pass extending the base Pass class.
     31 class PassDataHolder {
     32 };
     33 
     34 /**
     35  * @class Pass
     36  * @brief Base Pass class, can be extended to perform a more defined way of doing the work call.
     37  */
     38 class Pass {
     39  public:
     40   explicit Pass(const char* name)
     41     : pass_name_(name) {
     42   }
     43 
     44   virtual ~Pass() {
     45   }
     46 
     47   virtual const char* GetName() const {
     48     return pass_name_;
     49   }
     50 
     51   /**
     52    * @brief Gate for the pass: determines whether to execute the pass or not considering a CompilationUnit
     53    * @param data the PassDataHolder.
     54    * @return whether or not to execute the pass.
     55    */
     56   virtual bool Gate(const PassDataHolder* data) const {
     57     // Unused parameter.
     58     UNUSED(data);
     59 
     60     // Base class says yes.
     61     return true;
     62   }
     63 
     64   /**
     65    * @brief Start of the pass: called before the Worker function.
     66    */
     67   virtual void Start(PassDataHolder* data) const {
     68     // Unused parameter.
     69     UNUSED(data);
     70   }
     71 
     72   /**
     73    * @brief End of the pass: called after the WalkBasicBlocks function.
     74    */
     75   virtual void End(PassDataHolder* data) const {
     76     // Unused parameter.
     77     UNUSED(data);
     78   }
     79 
     80   /**
     81    * @param data the object containing data necessary for the pass.
     82    * @return whether or not there is a change when walking the BasicBlock
     83    */
     84   virtual bool Worker(const PassDataHolder* data) const {
     85     // Unused parameter.
     86     UNUSED(data);
     87 
     88     // BasicBlock did not change.
     89     return false;
     90   }
     91 
     92   static void BasePrintMessage(CompilationUnit* c_unit, const char* pass_name, const char* message, ...) {
     93     // Check if we want to log something or not.
     94     if (c_unit->print_pass) {
     95       // Stringify the message.
     96       va_list args;
     97       va_start(args, message);
     98       std::string stringified_message;
     99       StringAppendV(&stringified_message, message, args);
    100       va_end(args);
    101 
    102       // Log the message and ensure to include pass name.
    103       LOG(INFO) << pass_name << ": " << stringified_message;
    104     }
    105   }
    106 
    107  protected:
    108   /** @brief The pass name: used for searching for a pass when running a particular pass or debugging. */
    109   const char* const pass_name_;
    110 
    111  private:
    112   // In order to make the all passes not copy-friendly.
    113   DISALLOW_COPY_AND_ASSIGN(Pass);
    114 };
    115 }  // namespace art
    116 #endif  // ART_COMPILER_DEX_PASS_H_
    117