Add OptimizedCodeEntry as a new heap object type. An optimized code entry represents an association…

src/objects.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 113 matching lines @@
 //               - ExternalTwoByteInternalizedString
 //         - Symbol
 //       - HeapNumber
 //       - Cell
 //         - PropertyCell
 //       - Code
 //       - Map
 //       - Oddball
 //       - Foreign
 //       - SharedFunctionInfo
+//       - OptimizedCodeEntry
 //       - Struct
 //         - Box
 //         - DeclaredAccessorDescriptor
 //         - AccessorInfo
 //           - DeclaredAccessorInfo
 //           - ExecutableAccessorInfo
 //         - AccessorPair
 //         - AccessCheckInfo
 //         - InterceptorInfo
 //         - CallHandlerInfo
@@ skipping 255 matching lines @@
   V(SCRIPT_TYPE)                                                               \
   V(CODE_CACHE_TYPE)                                                           \
   V(POLYMORPHIC_CODE_CACHE_TYPE)                                               \
   V(TYPE_FEEDBACK_INFO_TYPE)                                                   \
   V(ALIASED_ARGUMENTS_ENTRY_TYPE)                                              \
   V(BOX_TYPE)                                                                  \
                                                                                \
   V(FIXED_ARRAY_TYPE)                                                          \
   V(FIXED_DOUBLE_ARRAY_TYPE)                                                   \
   V(SHARED_FUNCTION_INFO_TYPE)                                                 \
+  V(OPTIMIZED_CODE_ENTRY_TYPE)                                                 \
                                                                                \
   V(JS_MESSAGE_OBJECT_TYPE)                                                    \
                                                                                \
   V(JS_VALUE_TYPE)                                                             \
   V(JS_DATE_TYPE)                                                              \
   V(JS_OBJECT_TYPE)                                                            \
   V(JS_CONTEXT_EXTENSION_OBJECT_TYPE)                                          \
   V(JS_GENERATOR_OBJECT_TYPE)                                                  \
   V(JS_MODULE_TYPE)                                                            \
   V(JS_GLOBAL_OBJECT_TYPE)                                                     \
@@ skipping 330 matching lines @@
   BOX_TYPE,
   // The following two instance types are only used when ENABLE_DEBUGGER_SUPPORT
   // is defined. However as include/v8.h contain some of the instance type
   // constants always having them avoids them getting different numbers
   // depending on whether ENABLE_DEBUGGER_SUPPORT is defined or not.
   DEBUG_INFO_TYPE,
   BREAK_POINT_INFO_TYPE,
 
   FIXED_ARRAY_TYPE,
   SHARED_FUNCTION_INFO_TYPE,
+  OPTIMIZED_CODE_ENTRY_TYPE,
 
   JS_MESSAGE_OBJECT_TYPE,
 
   // All the following types are subtypes of JSReceiver, which corresponds to
   // objects in the JS sense. The first and the last type in this range are
   // the two forms of function. This organization enables using the same
   // compares for checking the JS_RECEIVER/SPEC_OBJECT range and the
   // NONCALLABLE_JS_OBJECT range.
   JS_FUNCTION_PROXY_TYPE,  // FIRST_JS_RECEIVER_TYPE, FIRST_JS_PROXY_TYPE
   JS_PROXY_TYPE,  // LAST_JS_PROXY_TYPE
@@ skipping 241 matching lines @@
   V(TypeFeedbackCells)                         \
   V(FixedArray)                                \
   V(FixedDoubleArray)                          \
   V(Context)                                   \
   V(NativeContext)                             \
   V(ScopeInfo)                                 \
   V(JSFunction)                                \
   V(Code)                                      \
   V(Oddball)                                   \
   V(SharedFunctionInfo)                        \
+  V(OptimizedCodeEntry)                        \
   V(JSValue)                                   \
   V(JSDate)                                    \
   V(JSMessageObject)                           \
   V(StringWrapper)                             \
   V(Foreign)                                   \
   V(Boolean)                                   \
   V(JSArray)                                   \
   V(JSArrayBuffer)                             \
   V(JSArrayBufferView)                         \
   V(JSTypedArray)                              \
@@ skipping 5805 matching lines @@
       ((kNative + kCompilerHintsSmiTagSize) / kBitsPerByte);
 #else
 #error Unknown byte ordering
 #endif
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(SharedFunctionInfo);
 };
 
 
+// An optimized code entry represents an association between the native
+// context, a function, optimized code, and the literals. The entries
+// are linked into two lists for efficient lookup: by native context
+// (linked through next_by_native_context), or by shared function
+// info (linked through next_by_shared_info).
+// The references to the native context, function, and code are weak,
+// in order not to leak native contexts or functions through
+// SharedFunctionInfo. This means an entry can become "dead" through GC.
+// Entries are cleaned up lazily as each list is traversed.

[Michael Starzinger, 2013/08/28 14:59:47]

nit: s/cleaned up/removed from the list/ IIUC?

+class OptimizedCodeEntry: public HeapObject {
+ public:
+  // [native_context]: The native context of this entry. (WEAK)
+  DECL_ACCESSORS(native_context, Context)
+
+  // [function]: The JSFunction of this entry. (WEAK)
+  DECL_ACCESSORS(function, JSFunction)
+
+  // [code]: The optimized code of this entry. (WEAK)
+  DECL_ACCESSORS(code, Code)
+
+  // [literals]: Array of literals for this entry.
+  DECL_ACCESSORS(literals, FixedArray)
+
+  // [next_by_shared_info]: The next link in the list, when traversing
+  // starting with a SharedFunctionInfo. (NULL if none).
+  DECL_ACCESSORS(next_by_shared_info, OptimizedCodeEntry)
+
+  // [next_by_native_context]: The next link in the list, when traversing
+  // starting with a native context. (NULL if none)
+  DECL_ACCESSORS(next_by_native_context, OptimizedCodeEntry)
+
+  // Casting.
+  static inline OptimizedCodeEntry* cast(Object* obj);
+
+  DECLARE_PRINTER(OptimizedCodeEntry)
+  DECLARE_VERIFIER(OptimizedCodeEntry)
+
+  // Layout description.
+  static const int kNativeContextOffset = JSObject::kHeaderSize;
+  static const int kFunctionOffset = kNativeContextOffset + kPointerSize;
+  static const int kCodeOffset = kFunctionOffset + kPointerSize;
+  static const int kLiteralsOffset = kCodeOffset + kPointerSize;
+  static const int kNextBySharedInfoOffset =
+      kLiteralsOffset + kPointerSize;
+  static const int kNextByNativeContextOffset =
+      kNextBySharedInfoOffset + kPointerSize;
+  static const int kCacheableOffset = kNextByNativeContextOffset + kPointerSize;
+  static const int kSize = kCacheableOffset + kIntSize;
+  static const int kAlignedSize = OBJECT_POINTER_ALIGN(kSize);
+
+  typedef FixedBodyDescriptor<kLiteralsOffset,
+                              kNextByNativeContextOffset + kPointerSize,
+                              kSize> BodyDescriptor;
+
+  // Kills an entry, nulling out its references to native context, function,
+  // and code.

[Michael Starzinger, 2013/08/28 14:59:47]

nit: ... and literals.

+  void Kill();
+  inline bool cacheable();
+  inline void set_cacheable(bool val);
+
+ private:
+  // Used internally during traversal to skip dead entries.
+  inline bool IsDead() {
+    return function() == NULL || code() == NULL;
+  }
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(OptimizedCodeEntry);
+};
+
+
 class JSGeneratorObject: public JSObject {
  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)
@@ skipping 3351 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_