Home | History | Annotate | Download | only in src 
      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_FUNC_NAME_INFERRER_H_
      6 #define V8_FUNC_NAME_INFERRER_H_
      7 
      8 #include "src/handles.h"
      9 #include "src/zone.h"
     10 
     11 namespace v8 {
     12 namespace internal {
     13 
     14 class AstRawString;
     15 class AstString;
     16 class AstValueFactory;
     17 class FunctionLiteral;
     18 
     19 // FuncNameInferrer is a stateful class that is used to perform name
     20 // inference for anonymous functions during static analysis of source code.
     21 // Inference is performed in cases when an anonymous function is assigned
     22 // to a variable or a property (see test-func-name-inference.cc for examples.)
     23 //
     24 // The basic idea is that during parsing of LHSs of certain expressions
     25 // (assignments, declarations, object literals) we collect name strings,
     26 // and during parsing of the RHS, a function literal can be collected. After
     27 // parsing the RHS we can infer a name for function literals that do not have
     28 // a name.
     29 class FuncNameInferrer : public ZoneObject {
     30  public:
     31   FuncNameInferrer(AstValueFactory* ast_value_factory, Zone* zone);
     32 
     33   // Returns whether we have entered name collection state.
     34   bool IsOpen() const { return !entries_stack_.is_empty(); }
     35 
     36   // Pushes an enclosing the name of enclosing function onto names stack.
     37   void PushEnclosingName(const AstRawString* name);
     38 
     39   // Enters name collection state.
     40   void Enter() {
     41     entries_stack_.Add(names_stack_.length(), zone());
     42   }
     43 
     44   // Pushes an encountered name onto names stack when in collection state.
     45   void PushLiteralName(const AstRawString* name);
     46 
     47   void PushVariableName(const AstRawString* name);
     48 
     49   // Adds a function to infer name for.
     50   void AddFunction(FunctionLiteral* func_to_infer) {
     51     if (IsOpen()) {
     52       funcs_to_infer_.Add(func_to_infer, zone());
     53     }
     54   }
     55 
     56   void RemoveLastFunction() {
     57     if (IsOpen() && !funcs_to_infer_.is_empty()) {
     58       funcs_to_infer_.RemoveLast();
     59     }
     60   }
     61 
     62   // Infers a function name and leaves names collection state.
     63   void Infer() {
     64     DCHECK(IsOpen());
     65     if (!funcs_to_infer_.is_empty()) {
     66       InferFunctionsNames();
     67     }
     68   }
     69 
     70   // Leaves names collection state.
     71   void Leave() {
     72     DCHECK(IsOpen());
     73     names_stack_.Rewind(entries_stack_.RemoveLast());
     74     if (entries_stack_.is_empty())
     75       funcs_to_infer_.Clear();
     76   }
     77 
     78  private:
     79   enum NameType {
     80     kEnclosingConstructorName,
     81     kLiteralName,
     82     kVariableName
     83   };
     84   struct Name {
     85     Name(const AstRawString* name, NameType type) : name(name), type(type) {}
     86     const AstRawString* name;
     87     NameType type;
     88   };
     89 
     90   Zone* zone() const { return zone_; }
     91 
     92   // Constructs a full name in dotted notation from gathered names.
     93   const AstString* MakeNameFromStack();
     94 
     95   // A helper function for MakeNameFromStack.
     96   const AstString* MakeNameFromStackHelper(int pos,
     97                                                const AstString* prev);
     98 
     99   // Performs name inferring for added functions.
    100   void InferFunctionsNames();
    101 
    102   AstValueFactory* ast_value_factory_;
    103   ZoneList<int> entries_stack_;
    104   ZoneList<Name> names_stack_;
    105   ZoneList<FunctionLiteral*> funcs_to_infer_;
    106   Zone* zone_;
    107 
    108   DISALLOW_COPY_AND_ASSIGN(FuncNameInferrer);
    109 };
    110 
    111 
    112 } }  // namespace v8::internal
    113 
    114 #endif  // V8_FUNC_NAME_INFERRER_H_
    115