CSE2410 Fall 2014 Bounce

// Copyright 2006-2009 the V8 project authors. All rights reserved.

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// modification, are permitted provided that the following conditions are

// met:

//

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//

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#ifndef V8_FUNC_NAME_INFERRER_H_

#define V8_FUNC_NAME_INFERRER_H_

namespace v8 { namespace internal {

// FuncNameInferrer is a stateful class that is used to perform name

// inference for anonymous functions during static analysis of source code.

// Inference is performed in cases when an anonymous function is assigned

// to a variable or a property (see test-func-name-inference.cc for examples.)

// The basic idea is that during AST traversal LHSs of expressions are

// always visited before RHSs. Thus, during visiting the LHS, a name can be

// collected, and during visiting the RHS, a function literal can be collected.

// Inference is performed while leaving the assignment node.

class FuncNameInferrer BASE_EMBEDDED {

 public:

  FuncNameInferrer() :

      entries_stack_(10),

      names_stack_(5),

      func_to_infer_(NULL),

      dot_(Factory::NewStringFromAscii(CStrVector("."))) {

  }

  bool IsOpen() const { return !entries_stack_.is_empty(); }

  void PushEnclosingName(Handle<String> name);

  void Enter() {

    entries_stack_.Add(names_stack_.length());

  }

  void Leave() {

    ASSERT(IsOpen());

    names_stack_.Rewind(entries_stack_.RemoveLast());

  }

  void PushName(Handle<String> name) {

    if (IsOpen()) {

      names_stack_.Add(name);

    }

  }

  void SetFuncToInfer(FunctionLiteral* func_to_infer) {

    if (IsOpen()) {

      // If we encounter another function literal after already having

      // encountered one, the second one replaces the first.

      func_to_infer_ = func_to_infer;

    }

  }

  void InferAndLeave() {

    ASSERT(IsOpen());

    MaybeInferFunctionName();

    Leave();

  }

 private:

  Handle<String> MakeNameFromStack();

  Handle<String> MakeNameFromStackHelper(int pos, Handle<String> prev);

  void MaybeInferFunctionName();

  List<int> entries_stack_;

  List<Handle<String> > names_stack_;

  FunctionLiteral* func_to_infer_;

  Handle<String> dot_;

  DISALLOW_COPY_AND_ASSIGN(FuncNameInferrer);

};

// A wrapper class that automatically calls InferAndLeave when

// leaving scope.

class ScopedFuncNameInferrer BASE_EMBEDDED {

 public:

  explicit ScopedFuncNameInferrer(FuncNameInferrer* inferrer) :

      inferrer_(inferrer),

      is_entered_(false) {}

  ~ScopedFuncNameInferrer() {

    if (is_entered_) {

      inferrer_->InferAndLeave();

    }

  }

  void Enter() {

    inferrer_->Enter();

    is_entered_ = true;

  }

 private:

  FuncNameInferrer* inferrer_;

  bool is_entered_;

  DISALLOW_COPY_AND_ASSIGN(ScopedFuncNameInferrer);

};

} }  // namespace v8::internal

#endif  // V8_FUNC_NAME_INFERRER_H_