heap.h.svn-base

Google浏览器V8内核代码

  // Please note this function does not perform a garbage collection.
  static Object* Allocate(Map* map, AllocationSpace space);

  // Allocates a JS Map in the heap.
  // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
  // failed.
  // Please note this function does not perform a garbage collection.
  static Object* AllocateMap(InstanceType instance_type, int instance_size);

  // Allocates a partial map for bootstrapping.
  static Object* AllocatePartialMap(InstanceType instance_type,
                                    int instance_size);

  // Allocate a map for the specified function
  static Object* AllocateInitialMap(JSFunction* fun);

  // Allocates and fully initializes a String.  There are two String
  // encodings: ASCII and two byte. One should choose between the three string
  // allocation functions based on the encoding of the string buffer used to
  // initialized the string.
  //   - ...FromAscii initializes the string from a buffer that is ASCII
  //     encoded (it does not check that the buffer is ASCII encoded) and the
  //     result will be ASCII encoded.
  //   - ...FromUTF8 initializes the string from a buffer that is UTF-8
  //     encoded.  If the characters are all single-byte characters, the
  //     result will be ASCII encoded, otherwise it will converted to two
  //     byte.
  //   - ...FromTwoByte initializes the string from a buffer that is two-byte
  //     encoded.  If the characters are all single-byte characters, the
  //     result will be converted to ASCII, otherwise it will be left as
  //     two-byte.
  // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
  // failed.
  // Please note this does not perform a garbage collection.
  static Object* AllocateStringFromAscii(
      Vector<const char> str,
      PretenureFlag pretenure = NOT_TENURED);
  static Object* AllocateStringFromUtf8(
      Vector<const char> str,
      PretenureFlag pretenure = NOT_TENURED);
  static Object* AllocateStringFromTwoByte(
      Vector<const uc16> str,
      PretenureFlag pretenure = NOT_TENURED);

  // Allocates a symbol in old space based on the character stream.
  // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
  // failed.
  // Please note this function does not perform a garbage collection.
  static Object* AllocateSymbol(unibrow::CharacterStream* buffer,
                                int chars,
                                int hash);

  // Allocates and partially initializes a String.  There are two String
  // encodings: ASCII and two byte.  These functions allocate a string of the
  // given length and set its map and length fields.  The characters of the
  // string are uninitialized.
  // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
  // failed.
  // Please note this does not perform a garbage collection.
  static Object* AllocateRawAsciiString(
      int length,
      PretenureFlag pretenure = NOT_TENURED);
  static Object* AllocateRawTwoByteString(
      int length,
      PretenureFlag pretenure = NOT_TENURED);

  // Computes a single character string where the character has code.
  // A cache is used for ascii codes.
  // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
  // failed. Please note this does not perform a garbage collection.
  static Object* LookupSingleCharacterStringFromCode(uint16_t code);

  // Allocate a byte array of the specified length
  // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
  // failed.
  // Please not this does not perform a garbage collection.
  static Object* AllocateByteArray(int length);

  // Allocates a fixed array initialized with undefined values
  // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
  // failed.
  // Please note this does not perform a garbage collection.
  static Object* AllocateFixedArray(int length,
                                    PretenureFlag pretenure = NOT_TENURED);


  // Allocates a fixed array initialized with the hole values.
  // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
  // failed.
  // Please note this does not perform a garbage collection.
  static Object* AllocateFixedArrayWithHoles(int length);

  // AllocateHashTable is identical to AllocateFixedArray except
  // that the resulting object has hash_table_map as map.
  static Object* AllocateHashTable(int length);

  // Allocate a global (but otherwise uninitialized) context.
  static Object* AllocateGlobalContext();

  // Allocate a function context.
  static Object* AllocateFunctionContext(int length, JSFunction* closure);

  // Allocate a 'with' context.
  static Object* AllocateWithContext(Context* previous, JSObject* extension);

  // Allocates a new utility object in the old generation.
  static Object* AllocateStruct(InstanceType type);


  // Initializes a function with a shared part and prototype.
  // Returns the function.
  // Note: this code was factored out of AllocateFunction such that
  // other parts of the VM could use it. Specifically, a function that creates
  // instances of type JS_FUNCTION_TYPE benefit from the use of this function.
  // Please note this does not perform a garbage collection.
  static Object* InitializeFunction(JSFunction* function,
                                    SharedFunctionInfo* shared,
                                    Object* prototype);

  // Allocates a function initialized with a shared part.
  // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
  // failed.
  // Please note this does not perform a garbage collection.
  static Object* AllocateFunction(Map* function_map,
                                  SharedFunctionInfo* shared,
                                  Object* prototype);

  // Indicies for direct access into argument objects.
  static const int arguments_callee_index = 0;
  static const int arguments_length_index = 1;

  // Allocates an arguments object - optionally with an elements array.
  // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
  // failed.
  // Please note this does not perform a garbage collection.
  static Object* AllocateArgumentsObject(Object* callee, int length);

  // Converts a double into either a Smi or a HeapNumber object.
  // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
  // failed.
  // Please note this does not perform a garbage collection.
  static Object* NewNumberFromDouble(double value,
                                     PretenureFlag pretenure = NOT_TENURED);

  // Same as NewNumberFromDouble, but may return a preallocated/immutable
  // number object (e.g., minus_zero_value_, nan_value_)
  static Object* NumberFromDouble(double value,
                                  PretenureFlag pretenure = NOT_TENURED);

  // Allocated a HeapNumber from value.
  static Object* AllocateHeapNumber(double value, PretenureFlag pretenure);
  static Object* AllocateHeapNumber(double value);  // pretenure = NOT_TENURED

  // Converts an int into either a Smi or a HeapNumber object.
  // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
  // failed.
  // Please note this does not perform a garbage collection.
  static inline Object* NumberFromInt32(int32_t value);

  // Converts an int into either a Smi or a HeapNumber object.
  // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
  // failed.
  // Please note this does not perform a garbage collection.
  static inline Object* NumberFromUint32(uint32_t value);

  // Allocates a new proxy object.
  // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
  // failed.
  // Please note this does not perform a garbage collection.
  static Object* AllocateProxy(Address proxy,
                               PretenureFlag pretenure = NOT_TENURED);

  // Allocates a new SharedFunctionInfo object.
  // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
  // failed.
  // Please note this does not perform a garbage collection.
  static Object* AllocateSharedFunctionInfo(Object* name);

  // Allocates a new cons string object.
  // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
  // failed.
  // Please note this does not perform a garbage collection.
  static Object* AllocateConsString(String* first, String* second);

  // Allocates a new sliced string object which is a slice of an underlying
  // string buffer stretching from the index start (inclusive) to the index
  // end (exclusive).
  // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
  // failed.
  // Please note this does not perform a garbage collection.
  static Object* AllocateSlicedString(String* buffer, int start, int end);

  // Allocates a new sub string object which is a substring of an underlying
  // string buffer stretching from the index start (inclusive) to the index
  // end (exclusive).
  // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
  // failed.
  // Please note this does not perform a garbage collection.
  static Object* AllocateSubString(String* buffer, int start, int end);

  // Allocate a new external string object, which is backed by a string
  // resource that resides outside the V8 heap.
  // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
  // failed.
  // Please note this does not perform a garbage collection.
  static Object* AllocateExternalStringFromAscii(
      ExternalAsciiString::Resource* resource);
  static Object* AllocateExternalStringFromTwoByte(
      ExternalTwoByteString::Resource* resource);

  // Allocates an uninitialized object.  The memory is non-executable if the
  // hardware and OS allow.
  // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
  // failed.
  // Please note this function does not perform a garbage collection.
  static inline Object* AllocateRaw(int size_in_bytes,
                                    AllocationSpace space);

  // Makes a new native code object
  // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
  // failed.
  // Please note this function does not perform a garbage collection.
  static Object* CreateCode(const CodeDesc& desc,
                            ScopeInfo<>* sinfo,
                            Code::Flags flags);

  static Object* CopyCode(Code* code);
  // Finds the symbol for string in the symbol table.
  // If not found, a new symbol is added to the table and returned.
  // Returns Failure::RetryAfterGC(requested_bytes, space) if allocation
  // failed.
  // Please note this function does not perform a garbage collection.
  static Object* LookupSymbol(Vector<const char> str);
  static Object* LookupAsciiSymbol(const char* str) {
    return LookupSymbol(CStrVector(str));
  }
  static Object* LookupSymbol(String* str);

  // Compute the matching symbol map for a string if possible.
  // NULL is returned if string is in new space or not flattened.
  static Map* SymbolMapForString(String* str);

  // Converts the given boolean condition to JavaScript boolean value.
  static Object* ToBoolean(bool condition) {
    return condition ? true_value() : false_value();
  }

  // Code that should be run before and after each GC.  Includes some
  // reporting/verification activities when compiled with DEBUG set.
  static void GarbageCollectionPrologue();
  static void GarbageCollectionEpilogue();

  // Performs garbage collection operation.
  // Returns whether required_space bytes are available after the collection.
  static bool CollectGarbage(int required_space, AllocationSpace space);

  // Performs a full garbage collection.
  static void CollectAllGarbage();

  // Utility to invoke the scavenger. This is needed in test code to
  // ensure correct callback for weak global handles.
  static void PerformScavenge();

  static void SetGlobalGCPrologueCallback(GCCallback callback) {
    global_gc_prologue_callback_ = callback;
  }
  static void SetGlobalGCEpilogueCallback(GCCallback callback) {
    global_gc_epilogue_callback_ = callback;
  }

  // Heap roots
#define ROOT_ACCESSOR(type, name) static type* name() { return name##_; }
  ROOT_LIST(ROOT_ACCESSOR)
#undef ROOT_ACCESSOR

// Utility type maps
#define STRUCT_MAP_ACCESSOR(NAME, Name, name) \
    static Map* name##_map() { return name##_map_; }
  STRUCT_LIST(STRUCT_MAP_ACCESSOR)
#undef STRUCT_MAP_ACCESSOR

#define SYMBOL_ACCESSOR(name, str) static String* name() { return name##_; }
  SYMBOL_LIST(SYMBOL_ACCESSOR)
#undef SYMBOL_ACCESSOR

  // Iterates over all roots in the heap.
  static void IterateRoots(ObjectVisitor* v);
  // Iterates over all strong roots in the heap.
  static void IterateStrongRoots(ObjectVisitor* v);

  // Iterates remembered set of an old space.
  static void IterateRSet(PagedSpace* space, ObjectSlotCallback callback);

  // Iterates a range of remembered set addresses starting with rset_start