1 // Copyright 2006-2009 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef V8_PARSING_FUNC_NAME_INFERRER_H_
6 #define V8_PARSING_FUNC_NAME_INFERRER_H_
7 
8 #include "src/zone/zone.h"
9 
10 namespace v8 {
11 namespace internal {
12 
13 class AstRawString;
14 class AstString;
15 class AstValueFactory;
16 class FunctionLiteral;
17 
18 enum class InferName { kYes, kNo };
19 
20 // FuncNameInferrer is a stateful class that is used to perform name
21 // inference for anonymous functions during static analysis of source code.
22 // Inference is performed in cases when an anonymous function is assigned
23 // to a variable or a property (see test-func-name-inference.cc for examples.)
24 //
25 // The basic idea is that during parsing of LHSs of certain expressions
26 // (assignments, declarations, object literals) we collect name strings,
27 // and during parsing of the RHS, a function literal can be collected. After
28 // parsing the RHS we can infer a name for function literals that do not have
29 // a name.
30 class FuncNameInferrer : public ZoneObject {
31  public:
32   FuncNameInferrer(AstValueFactory* ast_value_factory, Zone* zone);
33 
34   // To enter function name inference state, put a FuncNameInferrer::State
35   // on the stack.
36   class State {
37    public:
State(FuncNameInferrer * fni)38     explicit State(FuncNameInferrer* fni) : fni_(fni) {
39       if (fni_ != nullptr) fni_->Enter();
40     }
~State()41     ~State() {
42       if (fni_ != nullptr) fni_->Leave();
43     }
44 
45    private:
46     FuncNameInferrer* fni_;
47 
48     DISALLOW_COPY_AND_ASSIGN(State);
49   };
50 
51   // Returns whether we have entered name collection state.
IsOpen()52   bool IsOpen() const { return !entries_stack_.is_empty(); }
53 
54   // Pushes an enclosing the name of enclosing function onto names stack.
55   void PushEnclosingName(const AstRawString* name);
56 
57   // Pushes an encountered name onto names stack when in collection state.
58   void PushLiteralName(const AstRawString* name);
59 
60   void PushVariableName(const AstRawString* name);
61 
62   // Adds a function to infer name for.
AddFunction(FunctionLiteral * func_to_infer)63   void AddFunction(FunctionLiteral* func_to_infer) {
64     if (IsOpen()) {
65       funcs_to_infer_.Add(func_to_infer, zone());
66     }
67   }
68 
RemoveLastFunction()69   void RemoveLastFunction() {
70     if (IsOpen() && !funcs_to_infer_.is_empty()) {
71       funcs_to_infer_.RemoveLast();
72     }
73   }
74 
75   void RemoveAsyncKeywordFromEnd();
76 
77   // Infers a function name and leaves names collection state.
Infer()78   void Infer() {
79     DCHECK(IsOpen());
80     if (!funcs_to_infer_.is_empty()) {
81       InferFunctionsNames();
82     }
83   }
84 
85  private:
86   enum NameType {
87     kEnclosingConstructorName,
88     kLiteralName,
89     kVariableName
90   };
91   struct Name {
NameName92     Name(const AstRawString* name, NameType type) : name(name), type(type) {}
93     const AstRawString* name;
94     NameType type;
95   };
96 
Enter()97   void Enter() { entries_stack_.Add(names_stack_.length(), zone()); }
98 
Leave()99   void Leave() {
100     DCHECK(IsOpen());
101     names_stack_.Rewind(entries_stack_.RemoveLast());
102     if (entries_stack_.is_empty()) funcs_to_infer_.Clear();
103   }
104 
zone()105   Zone* zone() const { return zone_; }
106 
107   // Constructs a full name in dotted notation from gathered names.
108   const AstString* MakeNameFromStack();
109 
110   // A helper function for MakeNameFromStack.
111   const AstString* MakeNameFromStackHelper(int pos,
112                                                const AstString* prev);
113 
114   // Performs name inferring for added functions.
115   void InferFunctionsNames();
116 
117   AstValueFactory* ast_value_factory_;
118   ZoneList<int> entries_stack_;
119   ZoneList<Name> names_stack_;
120   ZoneList<FunctionLiteral*> funcs_to_infer_;
121   Zone* zone_;
122 
123   DISALLOW_COPY_AND_ASSIGN(FuncNameInferrer);
124 };
125 
126 
127 }  // namespace internal
128 }  // namespace v8
129 
130 #endif  // V8_PARSING_FUNC_NAME_INFERRER_H_
131