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Improve line info construction (#4718)

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- Simplify small encoding
- Better line info for some corner cases

JerryScript-DCO-1.0-Signed-off-by: Zoltan Herczeg zherczeg.u-szeged@partner.samsung.com
This commit is contained in:
Zoltan Herczeg
2021-07-16 16:08:38 +02:00
committed by GitHub
parent d5a7839632
commit 252d68936f
7 changed files with 61 additions and 64 deletions
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jerry-core/parser/js/js-parser-line-info-create.c
+10 -29
View File
@@ -38,8 +38,9 @@
* The format is big endian.
*
* Small:
* First byte can encode signed values between 127 and -125 in 1 byte.
* Large values requires more bytes than vlq.
* One byte can encode signed values between 127 and -126.
* Two byte can encode signed values between 319 and -318.
* Large values are encoded with vlq with a prefix byte.
*
* The line-info data structure is a sequence of chunks:
*
@@ -87,7 +88,7 @@
/**
* Maximum number of bytes requires to encode a number.
*/
#define PARSER_LINE_INFO_BUFFER_MAX_SIZE 5
#define PARSER_LINE_INFO_BUFFER_MAX_SIZE 6
/**
* Stream generation ends after this size is reached,
@@ -160,41 +161,21 @@ static uint32_t
parser_line_info_encode_small (uint8_t *buffer_p, /**< target buffer */
uint32_t value) /**< encoded value */
{
if (value < ECMA_LINE_INFO_ENCODE_TWO_BYTE_MIN)
if (JERRY_LIKELY (value < ECMA_LINE_INFO_ENCODE_TWO_BYTE_MIN))
{
buffer_p[0] = (uint8_t) value;
return 1;
}
uint32_t length;
if (JERRY_LIKELY (value < ECMA_LINE_INFO_ENCODE_THREE_BYTE_MIN))
if (JERRY_LIKELY (value < ECMA_LINE_INFO_ENCODE_VLQ_MIN))
{
value -= ECMA_LINE_INFO_ENCODE_TWO_BYTE_MIN;
buffer_p[0] = ECMA_LINE_INFO_ENCODE_TWO_BYTE;
length = 2;
}
else
{
if (value <= (ECMA_LINE_INFO_ENCODE_THREE_BYTE_MIN + UINT16_MAX))
{
value -= ECMA_LINE_INFO_ENCODE_THREE_BYTE_MIN;
buffer_p[0] = ECMA_LINE_INFO_ENCODE_THREE_BYTE;
length = 3;
}
else
{
buffer_p[0] = ECMA_LINE_INFO_ENCODE_FIVE_BYTE;
buffer_p[3] = (uint8_t) (value >> 16);
buffer_p[4] = (uint8_t) (value >> 24);
length = 5;
}
buffer_p[2] = (uint8_t) (value >> 8);
buffer_p[1] = (uint8_t) (value - ECMA_LINE_INFO_ENCODE_TWO_BYTE_MIN);
return 2;
}
buffer_p[1] = (uint8_t) value;
return length;
*buffer_p++ = ECMA_LINE_INFO_ENCODE_VLQ;
return parser_line_info_encode_vlq (buffer_p, value - ECMA_LINE_INFO_ENCODE_VLQ_MIN) + 1;
} /* parser_line_info_encode_small */
/**