[generators] Implement %GeneratorGetSourcePosition.

src/objects.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 
 #include "src/assert-scope.h"
@@ skipping 7345 matching lines @@
  public:
   // [function]: The function corresponding to this generator object.
   DECL_ACCESSORS(function, JSFunction)
 
   // [context]: The context of the suspended computation.
   DECL_ACCESSORS(context, Context)
 
   // [receiver]: The receiver of the suspended computation.
   DECL_ACCESSORS(receiver, Object)
 
-  // [input]: The most recent input value.
+  // [input]: For active generators: the most recent input value.
+  // (For suspended new-style generators, we abuse this field to store debug
+  // information.)
   DECL_ACCESSORS(input, Object)
 
   // [resume_mode]: The most recent resume mode.
   enum ResumeMode { kNext, kReturn, kThrow };
   DECL_INT_ACCESSORS(resume_mode)
 
-  // [continuation]: Offset into code of continuation.
+  // [continuation]
   //
-  // A positive offset indicates a suspended generator.  The special
+  // A positive value indicates a suspended generator.  The special
   // kGeneratorExecuting and kGeneratorClosed values indicate that a generator
   // cannot be resumed.
   inline int continuation() const;
   inline void set_continuation(int continuation);
-  inline bool is_closed();
-  inline bool is_executing();
-  inline bool is_suspended();
+  inline bool is_closed() const;
+  inline bool is_executing() const;
+  inline bool is_suspended() const;
+
+  // For suspended generators: the source position at which the generator
+  // is suspended.
+  int source_position() const;
 
   // [operand_stack]: Saved operand stack.
   DECL_ACCESSORS(operand_stack, FixedArray)
 
   DECLARE_CAST(JSGeneratorObject)
 
   // Dispatched behavior.
   DECLARE_VERIFIER(JSGeneratorObject)
 
   // Magic sentinel values for the continuation.
@@ skipping 3413 matching lines @@
     }
     return value;
   }
 };
 
 
 }  // NOLINT, false-positive due to second-order macros.
 }  // NOLINT, false-positive due to second-order macros.
 
 #endif  // V8_OBJECTS_H_