jerryscript/src/libecmaobjects/ecma-globals.h

/* Copyright 2014 Samsung Electronics Co., Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/** \addtogroup ecma ---TODO---
 * @{
 *
 * \addtogroup ecmatypes ECMA types
 * @{
 */

#ifndef JERRY_ECMA_GLOBALS_H
#define  JERRY_ECMA_GLOBALS_H

#include "globals.h"
#include "mem-allocator.h"

/** \addtogroup compressedpointer Compressed pointer
 * @{
 */

/**
 * Ecma-pointer field is used to calculate ecma-value's address.
 *
 * Ecma-pointer contains value's shifted offset from common Ecma-pointers' base.
 * The offset is shifted right by MEM_ALIGNMENT_LOG.
 * Least significant MEM_ALIGNMENT_LOG bits of non-shifted offset are zeroes.
 */
#define ECMA_POINTER_FIELD_WIDTH MEM_COMPRESSED_POINTER_WIDTH

/**
 * The NULL value for compressed pointers
 */
#define ECMA_NULL_POINTER MEM_COMPRESSED_POINTER_NULL

/**
 * @}
 */

/**
 * Type of ecma-value
 */
typedef enum
{
  ECMA_TYPE_SIMPLE, /**< simple value */
  ECMA_TYPE_NUMBER, /**< 64-bit integer */
  ECMA_TYPE_STRING, /**< pointer to description of a string */
  ECMA_TYPE_OBJECT, /**< pointer to description of an object */
  ECMA_TYPE__COUNT /**< count of types */
} ecma_type_t;

/**
 * Simple ecma-values
 */
typedef enum
{
  /**
   * Empty value is implementation defined value, used for:
   *   - representing empty value in completion values (see also: ECMA-262 v5, 8.9 Completion specification type);
   *   - values of uninitialized immutable bindings;
   *   - values of empty register variables.
   */
  ECMA_SIMPLE_VALUE_EMPTY,
  ECMA_SIMPLE_VALUE_UNDEFINED, /**< undefined value */
  ECMA_SIMPLE_VALUE_NULL, /**< null value */
  ECMA_SIMPLE_VALUE_FALSE, /**< boolean false */
  ECMA_SIMPLE_VALUE_TRUE, /**< boolean true */
  ECMA_SIMPLE_VALUE_ARRAY_REDIRECT, /**< implementation defined value for an array's elements that exists,
                                         but is stored directly in the array's property list
                                         (used for array elements with non-default attribute values) */
  ECMA_SIMPLE_VALUE__COUNT /** count of simple ecma-values */
} ecma_simple_value_t;

/**
 * Type of ecma-property
 */
typedef enum
{
  ECMA_PROPERTY_NAMEDDATA, /**< named data property */
  ECMA_PROPERTY_NAMEDACCESSOR, /**< named accessor property */
  ECMA_PROPERTY_INTERNAL /**< internal property */
} ecma_property_type_t;

/**
 * Type of block evaluation (completion) result.
 *
 * See also: ECMA-262 v5, 8.9.
 */
typedef enum
{
  ECMA_COMPLETION_TYPE_NORMAL, /**< default block completion */
  ECMA_COMPLETION_TYPE_RETURN, /**< block completed with return */
  ECMA_COMPLETION_TYPE_BREAK, /**< block completed with break */
  ECMA_COMPLETION_TYPE_CONTINUE, /**< block completed with continue */
  ECMA_COMPLETION_TYPE_THROW, /**< block completed with throw */
  ECMA_COMPLETION_TYPE_EXIT /**< implementation-defined completion type
                                 for finishing script execution */
} ecma_completion_type_t;

/**
 * Description of an ecma-value
 */
typedef struct
{
  /** Value type (ecma_type_t) */
  unsigned int value_type : 2;

  /**
   * Simple value (ecma_simple_value_t) or compressed pointer to value (depending on value_type)
   */
  unsigned int value : ECMA_POINTER_FIELD_WIDTH;
} __packed ecma_value_t;

/**
 * Description of a block completion value
 *
 * See also: ECMA-262 v5, 8.9.
 */
typedef struct
{
  /** Type (ecma_completion_type_t) */
  unsigned int type : 3;

  /** Value */
  ecma_value_t value;

  /** Target */
  unsigned int target : 8;
} __packed ecma_completion_value_t;

/**
 * Target value indicating that target field
 * of ecma_completion_value_t defines no target.
 */
#define ECMA_TARGET_ID_RESERVED 255

/**
 * Internal properties' identifiers.
 */
typedef enum
{
  ECMA_INTERNAL_PROPERTY_CLASS, /**< [[Class]] */
  ECMA_INTERNAL_PROPERTY_PROTOTYPE, /**< [[Prototype]] */
  ECMA_INTERNAL_PROPERTY_EXTENSIBLE, /**< [[Extensible]] */
  ECMA_INTERNAL_PROPERTY_SCOPE, /**< [[Scope]] */
  ECMA_INTERNAL_PROPERTY_CODE, /**< [[Code]] */
  ECMA_INTERNAL_PROPERTY_FORMAL_PARAMETERS, /**< [[FormalParameters]] */

  /** provideThis property of lexical environment */
  ECMA_INTERNAL_PROPERTY_PROVIDE_THIS,

  /** binding object of lexical environment */
  ECMA_INTERNAL_PROPERTY_BINDING_OBJECT,

  /** Part of an array, that is indexed by numbers */
  ECMA_INTERNAL_PROPERTY_NUMBER_INDEXED_ARRAY_VALUES,

  /** Part of an array, that is indexed by strings */
  ECMA_INTERNAL_PROPERTY_STRING_INDEXED_ARRAY_VALUES
} ecma_internal_property_id_t;

/**
 * Property's 'Writable' attribute's values description.
 */
typedef enum
{
  ECMA_PROPERTY_NOT_WRITABLE, /**< property's 'Writable' attribute is false */
  ECMA_PROPERTY_WRITABLE /**< property's 'Writable' attribute is true */
} ecma_property_writable_value_t;

/**
 * Property's 'Enumerable' attribute's values description.
 */
typedef enum
{
  ECMA_PROPERTY_NOT_ENUMERABLE, /**< property's 'Enumerable' attribute is false */
  ECMA_PROPERTY_ENUMERABLE /**< property's 'Enumerable' attribute is true */
} ecma_property_enumerable_value_t;

/**
 * Property's 'Configurable' attribute's values description.
 */
typedef enum
{
  ECMA_PROPERTY_NOT_CONFIGURABLE, /**< property's 'Configurable' attribute is false */
  ECMA_PROPERTY_CONFIGURABLE /**< property's 'Configurable' attribute is true */
} ecma_property_configurable_value_t;

/**
 * Description of ecma-property
 */
typedef struct ecma_property_t
{
  /** Property's type (ecma_property_type_t) */
  unsigned int type : 2;

  /** Compressed pointer to next property */
  unsigned int next_property_p : ECMA_POINTER_FIELD_WIDTH;

  /** Property's details (depending on Type) */
  union
  {
    /** Description of named data property */
    struct __packed ecma_named_data_property_t
    {
      /** Compressed pointer to property's name (pointer to String) */
      unsigned int name_p : ECMA_POINTER_FIELD_WIDTH;

      /** Attribute 'Writable' (ecma_property_writable_value_t) */
      unsigned int writable : 1;

      /** Attribute 'Enumerable' (ecma_property_enumerable_value_t) */
      unsigned int enumerable : 1;

      /** Attribute 'Configurable' (ecma_property_configurable_value_t) */
      unsigned int configurable : 1;

      /** Value */
      ecma_value_t value;
    } named_data_property;

    /** Description of named accessor property */
    struct __packed ecma_named_accessor_property_t
    {
      /** Compressed pointer to property's name (pointer to String) */
      unsigned int name_p : ECMA_POINTER_FIELD_WIDTH;

      /** Attribute 'Enumerable' (ecma_property_enumerable_value_t) */
      unsigned int enumerable : 1;

      /** Attribute 'Configurable' (ecma_property_configurable_value_t) */
      unsigned int configurable : 1;

      /** Compressed pointer to property's getter */
      unsigned int get_p : ECMA_POINTER_FIELD_WIDTH;

      /** Compressed pointer to property's setter */
      unsigned int set_p : ECMA_POINTER_FIELD_WIDTH;
    } named_accessor_property;

    /** Description of internal property */
    struct __packed ecma_internal_property_t
    {
      /** Internal property's type */
      unsigned int type : 4;

      /** Value (may be a compressed pointer) */
      uint32_t value;
    } internal_property;
  } u;
} ecma_property_t;

/**
 * Description of GC's information layout
 */
typedef struct
{
  /**
   * Reference counter of the object.
   *
   *  Number of references to the object from stack variables.
   */
  unsigned int refs : CONFIG_ECMA_REFERENCE_COUNTER_WIDTH;

  /**
   * Identifier of GC generation.
   */
  unsigned int generation : 2;

  /**
   * Compressed pointer to next object in the global list of objects with same generation.
   */
  unsigned int next : ECMA_POINTER_FIELD_WIDTH;

  /**
   * Marker that is set if the object was visited during graph traverse.
   */
  unsigned int visited : 1;

  /**
   * Flag indicating that the object may reference objects of younger generations in its properties.
   */
  unsigned int may_ref_younger_objects : 1;
} __packed ecma_gc_info_t;

/**
 * Types of lexical environments
 */
typedef enum
{
  ECMA_LEXICAL_ENVIRONMENT_DECLARATIVE, /**< declarative lexical environment */
  ECMA_LEXICAL_ENVIRONMENT_OBJECTBOUND /**< object-bound lexical environment */
} ecma_lexical_environment_type_t;

/**
 * Internal object types
 */
typedef enum
{
  ECMA_OBJECT_TYPE_GENERAL, /**< all objects that are not String (15.5), Function (15.3),
                                 Arguments (10.6), Array (15.4) specification-defined objects
                                 and not host objects */
  ECMA_OBJECT_TYPE_STRING, /**< String objects (15.5) */
  ECMA_OBJECT_TYPE_FUNCTION, /**< Function objects (15.3), created through 13.2 routine */
  ECMA_OBJECT_TYPE_BOUND_FUNCTION, /**< Function objects (15.3), created through 15.3.4.5 routine */
  ECMA_OBJECT_TYPE_ARGUMENTS, /**< Arguments object (10.6) */
  ECMA_OBJECT_TYPE_ARRAY, /**< Array object (15.4) */
  ECMA_OBJECT_TYPE_HOST /**< Host object */
} ecma_object_type_t;

/**
 * ECMA-defined object classes
 */
typedef enum
{
  ECMA_OBJECT_CLASS_OBJECT, /**< "Object" */
  ECMA_OBJECT_CLASS_FUNCTION, /**< "Function" */
  ECMA_OBJECT_CLASS_ARGUMENTS, /**< "Arguments" */
  ECMA_OBJECT_CLASS_ARRAY, /**< "Array" */
  ECMA_OBJECT_CLASS_BOOLEAN, /**< "Boolean" */
  ECMA_OBJECT_CLASS_DATE, /**< "Date" */
  ECMA_OBJECT_CLASS_ERROR, /**< "Error" */
  ECMA_OBJECT_CLASS_JSON, /**< "JSON" */
  ECMA_OBJECT_CLASS_MATH, /**< "Math" */
  ECMA_OBJECT_CLASS_NUMBER, /**< "Number" */
  ECMA_OBJECT_CLASS_REGEXP, /**< "RegExp" */
  ECMA_OBJECT_CLASS_STRING /**< "String" */
} ecma_object_class_t;

/**
 * Description of ECMA-object or lexical environment
 * (depending on is_lexical_environment).
 */
typedef struct ecma_object_t
{
  /** Compressed pointer to property list */
  unsigned int properties_p : ECMA_POINTER_FIELD_WIDTH;

  /** Flag indicating whether it is a general object (false)
       or a lexical environment (true) */
  unsigned int is_lexical_environment : 1;

  /**
   * Attributes of either general object or lexical environment
   * (depending on is_lexical_environment)
   */
  union
  {
    /**
     * A general object's attributes (if !is_lexical_environment)
     */
    struct
    {
      /** Attribute 'Extensible' */
      unsigned int extensible : 1;

      /** Implementation internal object type (ecma_object_type_t) */
      unsigned int type : 3;

      /** Compressed pointer to prototype object (ecma_object_t) */
      unsigned int prototype_object_p : ECMA_POINTER_FIELD_WIDTH;
    } __packed object;

    /**
     * A lexical environment's attribute (if is_lexical_environment)
     */
    struct
    {
      /**
       * Type of lexical environment (ecma_lexical_environment_type_t).
       */
      unsigned int type : 1;

      /** Compressed pointer to outer lexical environment */
      unsigned int outer_reference_p : ECMA_POINTER_FIELD_WIDTH;
    } __packed lexical_environment;

  } __packed u;

  /** GC's information */
  ecma_gc_info_t gc_info;

  FIXME(Remove aligned attribute after packing the struct)
} __packed __attribute__ ((aligned (16))) ecma_object_t;

/**
 * Description of ECMA property descriptor
 *
 * See also: ECMA-262 v5, 8.10.
 *
 * Note:
 *      If a component of descriptor is undefined then corresponding
 *      field should contain it's default value.
 */
typedef struct
{
  /** Is [[Value]] defined? */
  unsigned int is_value_defined : 1;

  /** Is [[Get]] defined? */
  unsigned int is_get_defined : 1;

  /** Is [[Set]] defined? */
  unsigned int is_set_defined : 1;

  /** Is [[Writable]] defined? */
  unsigned int is_writable_defined : 1;

  /** Is [[Enumerable]] defined? */
  unsigned int is_enumerable_defined : 1;

  /** Is [[Configurable]] defined? */
  unsigned int is_configurable_defined : 1;

  /** [[Value]] */
  ecma_value_t value;

  /** [[Get]] */
  ecma_object_t* get_p;

  /** [[Set]] */
  ecma_object_t* set_p;

  /** [[Writable]] */
  ecma_property_writable_value_t writable;

  /** [[Enumerable]] */
  ecma_property_enumerable_value_t enumerable;

  /** [[Configurable]] */
  ecma_property_configurable_value_t configurable;
} ecma_property_descriptor_t;

/**
 * Description of an ecma-character
 */
typedef uint8_t ecma_char_t;

/**
 * Description of an ecma-number
 */
typedef float ecma_number_t;

/**
 * Value '0' of ecma_number_t
 */
#define ECMA_NUMBER_ZERO ((ecma_number_t) 0)

/**
 * Value '1' of ecma_number_t
 */
#define ECMA_NUMBER_ONE  ((ecma_number_t) 1)

/**
 * Maximum number of characters in string representation of ecma-number
 */
#define ECMA_MAX_CHARS_IN_STRINGIFIED_NUMBER 512

/**
 * Maximum number of characters in string representation of ecma-uint32
 */
#define ECMA_MAX_CHARS_IN_STRINGIFIED_UINT32 32

/**
 * Maximum value of valid array index
 *
 * See also:
 *          ECMA-262 v5, 15.4
 */
#define ECMA_MAX_VALUE_OF_VALID_ARRAY_INDEX ((uint32_t) (-1))

/**
 * Description of arrays'/strings' length
 */
typedef uint16_t ecma_length_t;

/**
 * Description of an Array's header
 */
typedef struct
{
  /** Compressed pointer to next chunk */
  uint16_t next_chunk_p;

  /** Number of elements in the Array */
  ecma_length_t unit_number;
} ecma_array_header_t;

/**
 * Description of first chunk in a chain of chunks that contains an Array.
 */
typedef struct
{
  /** Array's header */
  ecma_array_header_t header;

  /** Elements */
  uint8_t data[ sizeof (uint64_t) - sizeof (ecma_array_header_t) ];
} ecma_array_first_chunk_t;

/**
 * Description of non-first chunk in a chain of chunks that contains an Array
 */
typedef struct
{
  /** Compressed pointer to next chunk */
  uint16_t next_chunk_p;

  /** Characters */
  uint8_t data[ sizeof (uint64_t) - sizeof (uint16_t) ];
} ecma_array_non_first_chunk_t;

/**
 * Identifier for ecma-string's actual data container
 */
typedef enum
{
  ECMA_STRING_CONTAINER_HEAP, /**< actual data is on the heap
                                   in ecma_array_non_first_chunk_t */
  ECMA_STRING_CONTAINER_LIT_TABLE, /**< actual data is in literal table */
  ECMA_STRING_CONTAINER_IN_DESCRIPTOR /**< actual data is locally in the string's descriptor */
} ecma_string_container_t;

FIXME (Move to library that should define the type (libserializer /* ? */))
/**
 * Index in literal table
 */
typedef uint32_t literal_index_t;

/**
 * ECMA string-value descriptor
 */
typedef struct
{
  /** Reference counter for the string */
  unsigned int refs : CONFIG_ECMA_REFERENCE_COUNTER_WIDTH;

  /** Where the string's data is placed (ecma_string_container_t) */
  unsigned int container : 2;

  /** String's length */
  ecma_length_t length;

  /**
   * Actual data or identifier of it's place in container (depending on 'container' field)
   */
  union
  {
    /** Index of string in literal table */
    literal_index_t lit_index;

    /** Compressed pointer to array_non_first_chunk_t */
    unsigned int chunk_cp : ECMA_POINTER_FIELD_WIDTH;

    /** Actual data if placed locally in the descriptor */
    ecma_char_t chars[ sizeof (uint64_t) - sizeof (uint32_t) ];
  } u;
} ecma_string_t;

/**
 * \addtogroup reference ECMA-reference
 * @{
 */

/**
 * ECMA-reference (see also: ECMA-262 v5, 8.7).
 */
typedef struct
{
  /** base value */
  ecma_value_t base;

  /** referenced name value pointer */
  const ecma_char_t *referenced_name_p;

  /** strict reference flag */
  bool is_strict;
} ecma_reference_t;

/**
 * @}
 */

#endif  /* JERRY_ECMA_GLOBALS_H */

/**
 * @}
 * @}
 */