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Refactor ecma value to store pointers directly in ecma values rather than compressing them. #1006

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Apr 15, 2016
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Refactor ecma value to store pointers directly in ecma values rather than compressing them. #1006

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30 changes: 15 additions & 15 deletions jerry-core/ecma/base/ecma-globals.h
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Original file line number Diff line number Diff line change
Expand Up @@ -58,7 +58,8 @@ 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_OBJECT, /**< pointer to description of an object */
ECMA_TYPE___MAX = ECMA_TYPE_OBJECT /** highest value for ecma types */
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AFAIK, the common suffix is __COUNT instead of __MAX.

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I introduced this form some time ago and use it nowadays. It is useful for switches.

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There is 36 matches for __COUNT and 6 matches for __MAX in the current source base. I'd prefer to use only one of them, because they mean the same. But this could be in a followup patch. Leave as is, the code looks good to me. :)

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Just a clarification comment: __MAX is the highest possible value, __COUNT is the number of possible values. If an enum is numbered from 0, as usual, then __COUNT == __MAX + 1. However, if enum labels have "arbitrarily" set values, then either __MAX or __COUNT may make no sense to use.

} ecma_type_t;

/**
Expand All @@ -85,34 +86,33 @@ typedef enum
/**
* Description of an ecma value
*
* Bit-field structure: type (2) | error (1) | value (ECMA_POINTER_FIELD_WIDTH)
* Bit-field structure: type (2) | error (1) | value (29)
*/
typedef uint32_t ecma_value_t;

#if UINTPTR_MAX <= UINT32_MAX

/**
* Value type (ecma_type_t)
* MEM_ALIGNMENT_LOG aligned pointers can be stored directly in ecma_value_t
*/
#define ECMA_VALUE_TYPE_POS (0)
#define ECMA_VALUE_TYPE_WIDTH (2)
#define ECMA_VALUE_CAN_STORE_UINTPTR_VALUE_DIRECTLY

#endif /* UINTPTR_MAX <= UINT32_MAX */

/**
* Value is error (boolean)
* Mask for ecma types in ecma_type_t
*/
#define ECMA_VALUE_ERROR_POS (ECMA_VALUE_TYPE_POS + \
ECMA_VALUE_TYPE_WIDTH)
#define ECMA_VALUE_ERROR_WIDTH (1)
#define ECMA_VALUE_TYPE_MASK 0x3u

/**
* Simple value (ecma_simple_value_t) or compressed pointer to value (depending on value_type)
* Error flag in ecma_type_t
*/
#define ECMA_VALUE_VALUE_POS (ECMA_VALUE_ERROR_POS + \
ECMA_VALUE_ERROR_WIDTH)
#define ECMA_VALUE_VALUE_WIDTH (ECMA_POINTER_FIELD_WIDTH)
#define ECMA_VALUE_ERROR_FLAG 0x4u

/**
* Size of ecma value description, in bits
* Shift for value part in ecma_type_t
*/
#define ECMA_VALUE_SIZE (ECMA_VALUE_VALUE_POS + ECMA_VALUE_VALUE_WIDTH)
#define ECMA_VALUE_SHIFT 3

/**
* Internal properties' identifiers.
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