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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_OPTIMIZING_GRAPH_CHECKER_H_
     18 #define ART_COMPILER_OPTIMIZING_GRAPH_CHECKER_H_
     19 
     20 #include "nodes.h"
     21 
     22 #include <ostream>
     23 
     24 namespace art {
     25 
     26 // A control-flow graph visitor performing various checks.
     27 class GraphChecker : public HGraphDelegateVisitor {
     28  public:
     29   explicit GraphChecker(HGraph* graph, const char* dump_prefix = "art::GraphChecker: ")
     30     : HGraphDelegateVisitor(graph),
     31       errors_(graph->GetArena()->Adapter(kArenaAllocGraphChecker)),
     32       dump_prefix_(dump_prefix),
     33       seen_ids_(graph->GetArena(),
     34                 graph->GetCurrentInstructionId(),
     35                 false,
     36                 kArenaAllocGraphChecker),
     37       blocks_storage_(graph->GetArena()->Adapter(kArenaAllocGraphChecker)),
     38       visited_storage_(graph->GetArena(), 0u, true, kArenaAllocGraphChecker) {}
     39 
     40   // Check the whole graph (in reverse post-order).
     41   void Run() {
     42     // VisitReversePostOrder is used instead of VisitInsertionOrder,
     43     // as the latter might visit dead blocks removed by the dominator
     44     // computation.
     45     VisitReversePostOrder();
     46   }
     47 
     48   void VisitBasicBlock(HBasicBlock* block) OVERRIDE;
     49 
     50   void VisitInstruction(HInstruction* instruction) OVERRIDE;
     51   void VisitPhi(HPhi* phi) OVERRIDE;
     52 
     53   void VisitBinaryOperation(HBinaryOperation* op) OVERRIDE;
     54   void VisitBooleanNot(HBooleanNot* instruction) OVERRIDE;
     55   void VisitBoundType(HBoundType* instruction) OVERRIDE;
     56   void VisitBoundsCheck(HBoundsCheck* check) OVERRIDE;
     57   void VisitCheckCast(HCheckCast* check) OVERRIDE;
     58   void VisitCondition(HCondition* op) OVERRIDE;
     59   void VisitConstant(HConstant* instruction) OVERRIDE;
     60   void VisitDeoptimize(HDeoptimize* instruction) OVERRIDE;
     61   void VisitIf(HIf* instruction) OVERRIDE;
     62   void VisitInstanceOf(HInstanceOf* check) OVERRIDE;
     63   void VisitInvokeStaticOrDirect(HInvokeStaticOrDirect* invoke) OVERRIDE;
     64   void VisitLoadException(HLoadException* load) OVERRIDE;
     65   void VisitNeg(HNeg* instruction) OVERRIDE;
     66   void VisitPackedSwitch(HPackedSwitch* instruction) OVERRIDE;
     67   void VisitReturn(HReturn* ret) OVERRIDE;
     68   void VisitReturnVoid(HReturnVoid* ret) OVERRIDE;
     69   void VisitSelect(HSelect* instruction) OVERRIDE;
     70   void VisitTryBoundary(HTryBoundary* try_boundary) OVERRIDE;
     71   void VisitTypeConversion(HTypeConversion* instruction) OVERRIDE;
     72 
     73   void HandleLoop(HBasicBlock* loop_header);
     74   void HandleBooleanInput(HInstruction* instruction, size_t input_index);
     75 
     76   // Was the last visit of the graph valid?
     77   bool IsValid() const {
     78     return errors_.empty();
     79   }
     80 
     81   // Get the list of detected errors.
     82   const ArenaVector<std::string>& GetErrors() const {
     83     return errors_;
     84   }
     85 
     86   // Print detected errors on output stream `os`.
     87   void Dump(std::ostream& os) const {
     88     for (size_t i = 0, e = errors_.size(); i < e; ++i) {
     89       os << dump_prefix_ << errors_[i] << std::endl;
     90     }
     91   }
     92 
     93  protected:
     94   // Report a new error.
     95   void AddError(const std::string& error) {
     96     errors_.push_back(error);
     97   }
     98 
     99   // The block currently visited.
    100   HBasicBlock* current_block_ = nullptr;
    101   // Errors encountered while checking the graph.
    102   ArenaVector<std::string> errors_;
    103 
    104  private:
    105   // String displayed before dumped errors.
    106   const char* const dump_prefix_;
    107   ArenaBitVector seen_ids_;
    108 
    109   // To reduce the total arena memory allocation, we reuse the same storage.
    110   ArenaVector<HBasicBlock*> blocks_storage_;
    111   ArenaBitVector visited_storage_;
    112 
    113   DISALLOW_COPY_AND_ASSIGN(GraphChecker);
    114 };
    115 
    116 }  // namespace art
    117 
    118 #endif  // ART_COMPILER_OPTIMIZING_GRAPH_CHECKER_H_
    119