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 class CodeGenerator;
30 
31 // A control-flow graph visitor performing various checks.
32 class GraphChecker : public HGraphDelegateVisitor {
33  public:
34   explicit GraphChecker(HGraph* graph,
35                         CodeGenerator* codegen = nullptr,
36                         const char* dump_prefix = "art::GraphChecker: ")
HGraphDelegateVisitor(graph)37     : HGraphDelegateVisitor(graph),
38       errors_(graph->GetAllocator()->Adapter(kArenaAllocGraphChecker)),
39       dump_prefix_(dump_prefix),
40       allocator_(graph->GetArenaStack()),
41       seen_ids_(&allocator_, graph->GetCurrentInstructionId(), false, kArenaAllocGraphChecker),
42       codegen_(codegen) {
43     seen_ids_.ClearAllBits();
44   }
45 
46   // Check the whole graph. The pass_change parameter indicates whether changes
47   // may have occurred during the just executed pass. The default value is
48   // conservatively "true" (something may have changed). The last_size parameter
49   // and return value pass along the observed graph sizes.
50   size_t Run(bool pass_change = true, size_t last_size = 0);
51 
52   void VisitBasicBlock(HBasicBlock* block) override;
53 
54   void VisitInstruction(HInstruction* instruction) override;
55   void VisitPhi(HPhi* phi) override;
56 
57   void VisitBinaryOperation(HBinaryOperation* op) override;
58   void VisitBooleanNot(HBooleanNot* instruction) override;
59   void VisitBoundType(HBoundType* instruction) override;
60   void VisitBoundsCheck(HBoundsCheck* check) override;
61   void VisitCheckCast(HCheckCast* check) override;
62   void VisitCondition(HCondition* op) override;
63   void VisitConstant(HConstant* instruction) override;
64   void VisitDeoptimize(HDeoptimize* instruction) override;
65   void VisitIf(HIf* instruction) override;
66   void VisitInstanceOf(HInstanceOf* check) override;
67   void VisitInvokeStaticOrDirect(HInvokeStaticOrDirect* invoke) override;
68   void VisitLoadException(HLoadException* load) override;
69   void VisitNeg(HNeg* instruction) override;
70   void VisitPackedSwitch(HPackedSwitch* instruction) override;
71   void VisitReturn(HReturn* ret) override;
72   void VisitReturnVoid(HReturnVoid* ret) override;
73   void VisitSelect(HSelect* instruction) override;
74   void VisitTryBoundary(HTryBoundary* try_boundary) override;
75   void VisitTypeConversion(HTypeConversion* instruction) override;
76 
77   void VisitVecOperation(HVecOperation* instruction) override;
78 
79   void CheckTypeCheckBitstringInput(HTypeCheckInstruction* check,
80                                     size_t input_pos,
81                                     bool check_value,
82                                     uint32_t expected_value,
83                                     const char* name);
84   void HandleTypeCheckInstruction(HTypeCheckInstruction* instruction);
85   void HandleLoop(HBasicBlock* loop_header);
86   void HandleBooleanInput(HInstruction* instruction, size_t input_index);
87 
88   // Was the last visit of the graph valid?
IsValid()89   bool IsValid() const {
90     return errors_.empty();
91   }
92 
93   // Get the list of detected errors.
GetErrors()94   const ArenaVector<std::string>& GetErrors() const {
95     return errors_;
96   }
97 
98   // Print detected errors on output stream `os`.
Dump(std::ostream & os)99   void Dump(std::ostream& os) const {
100     for (size_t i = 0, e = errors_.size(); i < e; ++i) {
101       os << dump_prefix_ << errors_[i] << std::endl;
102     }
103   }
104 
105   // Enable/Disable the reference type info check.
106   //
107   // Return: the previous status of the check.
108   bool SetRefTypeInfoCheckEnabled(bool value = true) {
109     bool old_value = check_reference_type_info_;
110     check_reference_type_info_ = value;
111     return old_value;
112   }
113 
114  protected:
115   // Report a new error.
AddError(const std::string & error)116   void AddError(const std::string& error) {
117     errors_.push_back(error);
118   }
119 
120   // The block currently visited.
121   HBasicBlock* current_block_ = nullptr;
122   // Errors encountered while checking the graph.
123   ArenaVector<std::string> errors_;
124 
125  private:
126   // String displayed before dumped errors.
127   const char* const dump_prefix_;
128   ScopedArenaAllocator allocator_;
129   ArenaBitVector seen_ids_;
130   // Whether to perform the reference type info check for instructions which use or produce
131   // object references, e.g. HNewInstance, HLoadClass.
132   // The default value is true.
133   bool check_reference_type_info_ = true;
134 
135   // Used to access target information.
136   CodeGenerator* codegen_;
137 
138   DISALLOW_COPY_AND_ASSIGN(GraphChecker);
139 };
140 
141 }  // namespace art
142 
143 #endif  // ART_COMPILER_OPTIMIZING_GRAPH_CHECKER_H_
144