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Property read entry vs. array part check tweak 

Check entry part before array part.  The order of the check doesn't matter
functionally because a property never exists in both parts.  Because there
is an array fast path, array index reads are rarely handled by the generic
property lookup code, so checking the entry part first performs a bit better.
pull/1634/head
Sami Vaarala 7 years ago
parent
ba66159954
commit
95d1e10971
1 changed files with 38 additions and 40 deletions
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  1. 78
      src-input/duk_hobject_props.c

78
src-input/duk_hobject_props.c
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@ -1677,42 +1677,18 @@ DUK_LOCAL duk_bool_t duk__get_own_propdesc_raw(duk_hthread *thr, duk_hobject *ob
out_desc->a_idx = -1;
/*
* Array part
*/
if (DUK_HOBJECT_HAS_ARRAY_PART(obj) && arr_idx != DUK__NO_ARRAY_INDEX) {
if (arr_idx < DUK_HOBJECT_GET_ASIZE(obj)) {
tv = DUK_HOBJECT_A_GET_VALUE_PTR(thr->heap, obj, arr_idx);
if (!DUK_TVAL_IS_UNUSED(tv)) {
DUK_DDD(DUK_DDDPRINT("-> found in array part"));
if (flags & DUK_GETDESC_FLAG_PUSH_VALUE) {
duk_push_tval(thr, tv);
}
/* implicit attributes */
out_desc->flags = DUK_PROPDESC_FLAG_WRITABLE |
DUK_PROPDESC_FLAG_CONFIGURABLE |
DUK_PROPDESC_FLAG_ENUMERABLE;
out_desc->a_idx = arr_idx;
goto prop_found;
}
}
/* assume array part is comprehensive (contains all array indexed elements
* or none of them); hence no need to check the entries part here.
*/
DUK_DDD(DUK_DDDPRINT("-> not found as a concrete property (has array part, "
"should be there if present)"));
goto prop_not_found_concrete;
}
/*
* Entries part
* Try entries part first because it's the common case.
*
* Array part lookups are usually handled by the array fast path, and
* are not usually inherited. Array and entry parts never contain the
* same keys so the entry part vs. array part order doesn't matter.
*/
duk_hobject_find_existing_entry(thr->heap, obj, key, &out_desc->e_idx, &out_desc->h_idx);
if (out_desc->e_idx >= 0) {
duk_int_t e_idx = out_desc->e_idx;
out_desc->flags = DUK_HOBJECT_E_GET_FLAGS(thr->heap, obj, e_idx);
if (out_desc->flags & DUK_PROPDESC_FLAG_ACCESSOR) {
if (DUK_UNLIKELY(out_desc->flags & DUK_PROPDESC_FLAG_ACCESSOR)) {
DUK_DDD(DUK_DDDPRINT("-> found accessor property in entry part"));
out_desc->get = DUK_HOBJECT_E_GET_VALUE_GETTER(thr->heap, obj, e_idx);
out_desc->set = DUK_HOBJECT_E_GET_VALUE_SETTER(thr->heap, obj, e_idx);
@ -1733,10 +1709,32 @@ DUK_LOCAL duk_bool_t duk__get_own_propdesc_raw(duk_hthread *thr, duk_hobject *ob
}
/*
* Not found as a concrete property, check for virtual properties.
* Try array part.
*/
prop_not_found_concrete:
if (DUK_HOBJECT_HAS_ARRAY_PART(obj) && arr_idx != DUK__NO_ARRAY_INDEX) {
if (arr_idx < DUK_HOBJECT_GET_ASIZE(obj)) {
tv = DUK_HOBJECT_A_GET_VALUE_PTR(thr->heap, obj, arr_idx);
if (!DUK_TVAL_IS_UNUSED(tv)) {
DUK_DDD(DUK_DDDPRINT("-> found in array part"));
if (flags & DUK_GETDESC_FLAG_PUSH_VALUE) {
duk_push_tval(thr, tv);
}
/* implicit attributes */
out_desc->flags = DUK_PROPDESC_FLAG_WRITABLE |
DUK_PROPDESC_FLAG_CONFIGURABLE |
DUK_PROPDESC_FLAG_ENUMERABLE;
out_desc->a_idx = arr_idx;
goto prop_found;
}
}
}
DUK_DDD(DUK_DDDPRINT("-> not found as a concrete property"));
/*
* Not found as a concrete property, check for virtual properties.
*/
if (!DUK_HOBJECT_HAS_VIRTUAL_PROPERTIES(obj)) {
/* Quick skip. */
@ -1882,7 +1880,7 @@ DUK_LOCAL duk_bool_t duk__get_own_propdesc_raw(duk_hthread *thr, duk_hobject *ob
*/
/*
* Not found as concrete or virtual
* Not found as concrete or virtual.
*/
prop_not_found:
@ -1890,7 +1888,7 @@ DUK_LOCAL duk_bool_t duk__get_own_propdesc_raw(duk_hthread *thr, duk_hobject *ob
return 0;
/*
* Found
* Found.
*
* Arguments object has exotic post-processing, see E5 Section 10.6,
* description of [[GetOwnProperty]] variant for arguments.
@ -1900,15 +1898,15 @@ DUK_LOCAL duk_bool_t duk__get_own_propdesc_raw(duk_hthread *thr, duk_hobject *ob
DUK_DDD(DUK_DDDPRINT("-> property found, checking for arguments exotic post-behavior"));
/* Notes:
* - only numbered indices are relevant, so arr_idx fast reject is good
* - Only numbered indices are relevant, so arr_idx fast reject is good
* (this is valid unless there are more than 4**32-1 arguments).
* - since variable lookup has no side effects, this can be skipped if
* - Since variable lookup has no side effects, this can be skipped if
* DUK_GETDESC_FLAG_PUSH_VALUE is not set.
*/
if (DUK_HOBJECT_HAS_EXOTIC_ARGUMENTS(obj) &&
arr_idx != DUK__NO_ARRAY_INDEX &&
(flags & DUK_GETDESC_FLAG_PUSH_VALUE)) {
if (DUK_UNLIKELY(DUK_HOBJECT_HAS_EXOTIC_ARGUMENTS(obj) &&
arr_idx != DUK__NO_ARRAY_INDEX &&
(flags & DUK_GETDESC_FLAG_PUSH_VALUE))) {
duk_propdesc temp_desc;
/* Magically bound variable cannot be an accessor. However,
@ -3057,7 +3055,7 @@ duk_bool_t duk__handle_put_array_length_smaller(duk_hthread *thr,
return 1;
} else {
/*
* Entries part is a bit more complex
* Entries part is a bit more complex.
*/
/* Stage 1: find highest preventing non-configurable entry (if any).

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