1 /*
2  * Copyright (C) 2011 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_SEA_IR_TYPES_TYPE_INFERENCE_VISITOR_H_
18 #define ART_COMPILER_SEA_IR_TYPES_TYPE_INFERENCE_VISITOR_H_
19 
20 
21 #include "dex_file-inl.h"
22 #include "sea_ir/ir/visitor.h"
23 #include "sea_ir/types/types.h"
24 
25 namespace sea_ir {
26 
27 // The TypeInferenceVisitor visits each instruction and computes its type taking into account
28 //   the current type of the operands. The type is stored in the visitor.
29 // We may be better off by using a separate visitor type hierarchy that has return values
30 //   or that passes data as parameters, than to use fields to store information that should
31 //   in fact be returned after visiting each element. Ideally, I would prefer to use templates
32 //   to specify the returned value type, but I am not aware of a possible implementation
33 //   that does not horribly duplicate the visitor infrastructure code (version 1: no return value,
34 //   version 2: with template return value).
35 class TypeInferenceVisitor: public IRVisitor {
36  public:
TypeInferenceVisitor(SeaGraph * graph,TypeData * type_data,art::verifier::RegTypeCache * types)37   TypeInferenceVisitor(SeaGraph* graph, TypeData* type_data,
38       art::verifier::RegTypeCache* types):
39     graph_(graph), type_data_(type_data), type_cache_(types), crt_type_() {
40   }
41   // There are no type related actions to be performed on these classes.
Initialize(SeaGraph * graph)42   void Initialize(SeaGraph* graph) { }
43   void Visit(SeaGraph* graph);
Visit(Region * region)44   void Visit(Region* region) { }
45 
46   void Visit(PhiInstructionNode* instruction);
47   void Visit(SignatureNode* parameter);
Visit(InstructionNode * instruction)48   void Visit(InstructionNode* instruction) { }
49   void Visit(UnnamedConstInstructionNode* instruction);
Visit(ConstInstructionNode * instruction)50   void Visit(ConstInstructionNode* instruction) { }
Visit(ReturnInstructionNode * instruction)51   void Visit(ReturnInstructionNode* instruction) { }
Visit(IfNeInstructionNode * instruction)52   void Visit(IfNeInstructionNode* instruction) { }
53   void Visit(MoveResultInstructionNode* instruction);
54   void Visit(InvokeStaticInstructionNode* instruction);
55   void Visit(AddIntInstructionNode* instruction);
Visit(GotoInstructionNode * instruction)56   void Visit(GotoInstructionNode* instruction) { }
Visit(IfEqzInstructionNode * instruction)57   void Visit(IfEqzInstructionNode* instruction) { }
58 
59   const Type* MergeTypes(std::vector<const Type*>& types) const;
60   const Type* MergeTypes(const Type* t1, const Type* t2) const;
61   std::vector<const Type*> GetOperandTypes(InstructionNode* instruction) const;
GetType()62   const Type* GetType() {
63     // TODO: Currently multiple defined types are not supported.
64     if (!crt_type_.empty()) {
65       const Type* single_type = crt_type_.at(0);
66       crt_type_.clear();
67       return single_type;
68     }
69     return NULL;
70   }
71 
72  protected:
73   const SeaGraph* const graph_;
74   TypeData* type_data_;
75   art::verifier::RegTypeCache* type_cache_;
76   std::vector<const Type*> crt_type_;             // Stored temporarily between two calls to Visit.
77 };
78 
79 }  // namespace sea_ir
80 
81 #endif  // ART_COMPILER_SEA_IR_TYPES_TYPE_INFERENCE_VISITOR_H_
82