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Improve ecma_string_t descriptor (#3016)

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This patch introduces several changes conntect to ecma-strings:
 - Extend the size of the reference counter to 28 bytes from 13
 - Extend the size of the string hash to 32 bytes from 16 to use the extact FNV-1a hash
 - Introduce ECMA_STATIC_STRING_FLAG to reduce the number of string ref/derefs for static strings.
 - Introduce ECMA_STRING_CONTAINER_ASCII_STRING to store run-time allocated ASCII strings more efficiently
 - Remove ECMA_STRING_CONTAINER_LIT_NUMBER to half the storage size of the parsing time allocated floating point numbers
 - Rework the global number storage, to store only the floating point numbers
 - Optimize the lookup in the global number/string/symbol tables via reduce the number of NULL checks during decompressing the next element pointers
 - Reduce the code duplication in ecma_concat_ecma_strings and ecma_append_chars_to_string
 - Improve ecma_string_get_char with optional arguments to make it more reusable.

JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik frobert@inf.u-szeged.hu
This commit is contained in:
Robert Fancsik
2019-08-30 15:16:27 +02:00
committed by GitHub
parent f0578b2c25
commit c6a4a86257
15 changed files with 799 additions and 618 deletions
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jerry-core/ecma/base/ecma-globals.h
+93 -36
View File
@@ -1330,9 +1330,6 @@ typedef enum
#define ECMA_GET_DIRECT_STRING_VALUE(string_p) \
(((uintptr_t) (string_p)) >> ECMA_DIRECT_STRING_SHIFT)
/**
* Identifier for ecma-string's actual data container
*/
typedef enum
{
ECMA_STRING_CONTAINER_HEAP_UTF8_STRING, /**< actual data is on the heap as an utf-8 (cesu8) string
@@ -1341,17 +1338,15 @@ typedef enum
* maximum size is 2^32. */
ECMA_STRING_CONTAINER_UINT32_IN_DESC, /**< actual data is UInt32-represeneted Number
stored locally in the string's descriptor */
ECMA_STRING_CONTAINER_HEAP_ASCII_STRING, /**< actual data is on the heap as an ASCII string
* maximum size is 2^16. */
ECMA_STRING_CONTAINER_MAGIC_STRING_EX, /**< the ecma-string is equal to one of external magic strings */
ECMA_STRING_CONTAINER_SYMBOL, /**< the ecma-string is a symbol */
ECMA_STRING_CONTAINER_MAP_KEY, /**< the ecma-string is a map key string */
ECMA_STRING_LITERAL_NUMBER, /**< a literal number which is used solely by the literal storage
* so no string processing function supports this type except
* the ecma_deref_ecma_string function. */
ECMA_STRING_CONTAINER__MAX = ECMA_STRING_LITERAL_NUMBER /**< maximum value */
ECMA_STRING_CONTAINER__MAX = ECMA_STRING_CONTAINER_MAP_KEY /**< maximum value */
} ecma_string_container_t;
/**
@@ -1362,12 +1357,29 @@ typedef enum
/**
* Value for increasing or decreasing the reference counter.
*/
#define ECMA_STRING_REF_ONE (1u << 3)
#define ECMA_STRING_REF_ONE (1u << 4)
/**
* Maximum value of the reference counter (8191).
* Maximum value of the reference counter (4294967280).
*/
#define ECMA_STRING_MAX_REF (0x1fffu << 3)
#define ECMA_STRING_MAX_REF (0xFFFFFFF0)
/**
* Flag that identifies that the string is static which means it is stored in JERRY_CONTEXT (string_list_cp)
*/
#define ECMA_STATIC_STRING_FLAG (1 << 3)
/**
* Set an ecma-string as static string
*/
#define ECMA_SET_STRING_AS_STATIC(string_p) \
(string_p)->refs_and_container |= ECMA_STATIC_STRING_FLAG
/**
* Checks whether the ecma-string is static string
*/
#define ECMA_STRING_IS_STATIC(string_p) \
((string_p)->refs_and_container & ECMA_STATIC_STRING_FLAG)
/**
* Returns with the container type of a string.
@@ -1379,7 +1391,7 @@ typedef enum
* Checks whether the reference counter is 1.
*/
#define ECMA_STRING_IS_REF_EQUALS_TO_ONE(string_desc_p) \
(((string_desc_p)->refs_and_container >> 3) == 1)
(((string_desc_p)->refs_and_container >> 4) == 1)
/**
* ECMA string-value descriptor
@@ -1387,43 +1399,79 @@ typedef enum
typedef struct
{
/** Reference counter for the string */
uint16_t refs_and_container;
/** Hash of the string (calculated from two last characters of the string) */
lit_string_hash_t hash;
uint32_t refs_and_container;
/**
* Actual data or identifier of it's place in container (depending on 'container' field)
*/
union
{
/**
* Actual data of an utf-8 string type
*/
struct
{
uint16_t size; /**< size of this utf-8 string in bytes */
uint16_t length; /**< length of this utf-8 string in characters */
} utf8_string;
lit_utf8_size_t long_utf8_string_size; /**< size of this long utf-8 string in bytes */
uint32_t uint32_number; /**< uint32-represented number placed locally in the descriptor */
lit_string_hash_t hash; /**< hash of the ASCII/UTF8 string */
uint32_t magic_string_ex_id; /**< identifier of an external magic string (lit_magic_string_ex_id_t) */
ecma_value_t lit_number; /**< number (see ECMA_STRING_LITERAL_NUMBER) */
uint32_t common_uint32_field; /**< for zeroing and comparison in some cases */
ecma_value_t symbol_descriptor; /**< symbol descriptor string-value */
ecma_value_t value; /**< original key value corresponds to the map key string */
uint32_t uint32_number; /**< uint32-represented number placed locally in the descriptor */
} u;
} ecma_string_t;
/**
* Long ECMA string-value descriptor
* ECMA ASCII string-value descriptor
*/
typedef struct
{
ecma_string_t header; /**< string header */
lit_utf8_size_t long_utf8_string_length; /**< length of this long utf-8 string in bytes */
} ecma_long_string_t;
uint16_t size; /**< size of this ASCII string in bytes */
} ecma_ascii_string_t;
/**
* ECMA long UTF8 string-value descriptor
*/
typedef struct
{
ecma_string_t header; /**< string header */
uint16_t size; /**< size of this utf-8 string in bytes */
uint16_t length; /**< length of this utf-8 string in bytes */
} ecma_utf8_string_t;
/**
* ECMA UTF8 string-value descriptor
*/
typedef struct
{
ecma_string_t header; /**< string header */
lit_utf8_size_t size; /**< size of this long utf-8 string in bytes */
lit_utf8_size_t length; /**< length of this long utf-8 string in bytes */
} ecma_long_utf8_string_t;
/**
* Get the start position of the string buffer of an ecma ASCII string
*/
#define ECMA_ASCII_STRING_GET_BUFFER(string_p) \
((lit_utf8_byte_t *) ((lit_utf8_byte_t *) (string_p) + sizeof (ecma_ascii_string_t)))
/**
* Get the start position of the string buffer of an ecma UTF8 string
*/
#define ECMA_UTF8_STRING_GET_BUFFER(string_p) \
((lit_utf8_byte_t *) ((lit_utf8_byte_t *) (string_p) + sizeof (ecma_utf8_string_t)))
/**
* Get the start position of the string buffer of an ecma long UTF8 string
*/
#define ECMA_LONG_UTF8_STRING_GET_BUFFER(string_p) \
((lit_utf8_byte_t *) ((lit_utf8_byte_t *) (string_p) + sizeof (ecma_long_utf8_string_t)))
/**
* ECMA extended string-value descriptor
*/
typedef struct
{
ecma_string_t header; /**< string header */
union
{
ecma_value_t symbol_descriptor; /**< symbol descriptor string-value */
ecma_value_t value; /**< original key value corresponds to the map key string */
} u;
} ecma_extended_string_t;
/**
* String builder header
@@ -1437,13 +1485,13 @@ typedef struct
* Get pointer to the beginning of the stored string in the string builder
*/
#define ECMA_STRINGBUILDER_STRING_PTR(header_p) \
((lit_utf8_byte_t *) (((ecma_string_t *) header_p) + 1))
((lit_utf8_byte_t *) (((lit_utf8_byte_t *) header_p) + sizeof (ecma_ascii_string_t)))
/**
* Get the size of the stored string in the string builder
*/
#define ECMA_STRINGBUILDER_STRING_SIZE(header_p) \
((lit_utf8_size_t) (header_p->current_size - sizeof (ecma_string_t)))
((lit_utf8_size_t) (header_p->current_size - sizeof (ecma_ascii_string_t)))
/**
* String builder handle
@@ -1507,6 +1555,15 @@ typedef struct
jmem_cpointer_t values[ECMA_LIT_STORAGE_VALUE_COUNT]; /**< list of values */
} ecma_lit_storage_item_t;
/**
* Number storage item
*/
typedef struct
{
jmem_cpointer_t next_cp; /**< cpointer ot next item */
jmem_cpointer_t values[ECMA_LIT_STORAGE_VALUE_COUNT]; /**< list of values */
} ecma_number_storage_item_t;
#if ENABLED (JERRY_LCACHE)
/**
* Container of an LCache entry identifier