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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 <ostream>
21 
22 #include "base/arena_bit_vector.h"
23 #include "base/bit_vector-inl.h"
24 #include "base/scoped_arena_allocator.h"
25 #include "nodes.h"
26 
27 namespace art {
28 
29 // A control-flow graph visitor performing various checks.
30 class GraphChecker : public HGraphDelegateVisitor {
31  public:
32   explicit GraphChecker(HGraph* graph, const char* dump_prefix = "art::GraphChecker: ")
HGraphDelegateVisitor(graph)33     : HGraphDelegateVisitor(graph),
34       errors_(graph->GetAllocator()->Adapter(kArenaAllocGraphChecker)),
35       dump_prefix_(dump_prefix),
36       allocator_(graph->GetArenaStack()),
37       seen_ids_(&allocator_, graph->GetCurrentInstructionId(), false, kArenaAllocGraphChecker) {
38     seen_ids_.ClearAllBits();
39   }
40 
41   // Check the whole graph. The pass_change parameter indicates whether changes
42   // may have occurred during the just executed pass. The default value is
43   // conservatively "true" (something may have changed). The last_size parameter
44   // and return value pass along the observed graph sizes.
45   size_t Run(bool pass_change = true, size_t last_size = 0);
46 
47   void VisitBasicBlock(HBasicBlock* block) override;
48 
49   void VisitInstruction(HInstruction* instruction) override;
50   void VisitPhi(HPhi* phi) override;
51 
52   void VisitBinaryOperation(HBinaryOperation* op) override;
53   void VisitBooleanNot(HBooleanNot* instruction) override;
54   void VisitBoundType(HBoundType* instruction) override;
55   void VisitBoundsCheck(HBoundsCheck* check) override;
56   void VisitCheckCast(HCheckCast* check) override;
57   void VisitCondition(HCondition* op) override;
58   void VisitConstant(HConstant* instruction) override;
59   void VisitDeoptimize(HDeoptimize* instruction) override;
60   void VisitIf(HIf* instruction) override;
61   void VisitInstanceOf(HInstanceOf* check) override;
62   void VisitInvokeStaticOrDirect(HInvokeStaticOrDirect* invoke) override;
63   void VisitLoadException(HLoadException* load) override;
64   void VisitNeg(HNeg* instruction) override;
65   void VisitPackedSwitch(HPackedSwitch* instruction) override;
66   void VisitReturn(HReturn* ret) override;
67   void VisitReturnVoid(HReturnVoid* ret) override;
68   void VisitSelect(HSelect* instruction) override;
69   void VisitTryBoundary(HTryBoundary* try_boundary) override;
70   void VisitTypeConversion(HTypeConversion* instruction) override;
71 
72   void CheckTypeCheckBitstringInput(HTypeCheckInstruction* check,
73                                     size_t input_pos,
74                                     bool check_value,
75                                     uint32_t expected_value,
76                                     const char* name);
77   void HandleTypeCheckInstruction(HTypeCheckInstruction* instruction);
78   void HandleLoop(HBasicBlock* loop_header);
79   void HandleBooleanInput(HInstruction* instruction, size_t input_index);
80 
81   // Was the last visit of the graph valid?
IsValid()82   bool IsValid() const {
83     return errors_.empty();
84   }
85 
86   // Get the list of detected errors.
GetErrors()87   const ArenaVector<std::string>& GetErrors() const {
88     return errors_;
89   }
90 
91   // Print detected errors on output stream `os`.
Dump(std::ostream & os)92   void Dump(std::ostream& os) const {
93     for (size_t i = 0, e = errors_.size(); i < e; ++i) {
94       os << dump_prefix_ << errors_[i] << std::endl;
95     }
96   }
97 
98   // Enable/Disable the reference type info check.
99   //
100   // Return: the previous status of the check.
101   bool SetRefTypeInfoCheckEnabled(bool value = true) {
102     bool old_value = check_reference_type_info_;
103     check_reference_type_info_ = value;
104     return old_value;
105   }
106 
107  protected:
108   // Report a new error.
AddError(const std::string & error)109   void AddError(const std::string& error) {
110     errors_.push_back(error);
111   }
112 
113   // The block currently visited.
114   HBasicBlock* current_block_ = nullptr;
115   // Errors encountered while checking the graph.
116   ArenaVector<std::string> errors_;
117 
118  private:
119   // String displayed before dumped errors.
120   const char* const dump_prefix_;
121   ScopedArenaAllocator allocator_;
122   ArenaBitVector seen_ids_;
123   // Whether to perform the reference type info check for instructions which use or produce
124   // object references, e.g. HNewInstance, HLoadClass.
125   // The default value is true.
126   bool check_reference_type_info_ = true;
127 
128   DISALLOW_COPY_AND_ASSIGN(GraphChecker);
129 };
130 
131 }  // namespace art
132 
133 #endif  // ART_COMPILER_OPTIMIZING_GRAPH_CHECKER_H_
134