Verify that source string matches serialized code.

src/objects.h

 // Copyright 2012 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 "src/allocation.h"
 #include "src/assert-scope.h"
 #include "src/builtins.h"
@@ skipping 8836 matching lines @@
 
   int length_;
   uint32_t raw_running_hash_;
   uint32_t array_index_;
   bool is_array_index_;
   bool is_first_char_;
   DISALLOW_COPY_AND_ASSIGN(StringHasher);
 };
 
 
+class IteratingStringHasher : public StringHasher {
+ public:
+  static inline uint32_t Hash(String* string, uint32_t seed);
+  inline void VisitOneByteString(const uint8_t* chars, int length);
+  inline void VisitTwoByteString(const uint16_t* chars, int length);
+
+ private:
+  inline IteratingStringHasher(int len, uint32_t seed)
+      : StringHasher(len, seed) {}
+  DISALLOW_COPY_AND_ASSIGN(IteratingStringHasher);
+};

[vogelheim, 2014/07/15 13:42:31]

design nitpick: Not sure if exposing this class is the best choice. Given that -
because of the private constructor - the only use is to call
IteratingStringHasher::Hash, maybe one could simply add the static method to
StringHasher, and then IteratingStringHasher could remain an anonymous helper
class in objects.cc.

+
+
 // The characteristics of a string are stored in its map.  Retrieving these
 // few bits of information is moderately expensive, involving two memory
 // loads where the second is dependent on the first.  To improve efficiency
 // the shape of the string is given its own class so that it can be retrieved
 // once and used for several string operations.  A StringShape is small enough
 // to be passed by value and is immutable, but be aware that flattening a
 // string can potentially alter its shape.  Also be aware that a GC caused by
 // something else can alter the shape of a string due to ConsString
 // shortcutting.  Keeping these restrictions in mind has proven to be error-
 // prone and so we no longer put StringShapes in variables unless there is a
@@ skipping 2360 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_