Previously, both string_position and view_index used code unit offsets
regardless of mode. Now in unicode mode, these variables track code
point positions while string_position_in_code_units is properly
updated to reflect code unit offsets.
This commit implements support for forward references to named capture
groups. We now allow patterns like \k<name>(?<name>x) and
self-references like (?<name>\k<name>x).
Previously, named capture groups in RegExp results did not always follow
their source order, and unmatched groups were omitted. According to the
spec, all named capture groups must appear in the result object in the
order they are defined, even if they did not participate in the match.
This commit makes sure we follow this requirement.
The optimization for non-shared ArrayBuffers operates on incorrect
values of from_byte_index and to_byte_index because they will have been
modified in the preceding steps. This causes the incorrect range to be
copied within the buffer.
Before this change, PropertyNameIterator (used by for..in) and
`Object::enumerable_own_property_names()` (used by `Object.keys()`,
`Object.values()`, and `Object.entries()`) enumerated an object's own
enumerable properties exactly as the spec prescribes:
- Call `internal_own_property_keys()`, allocating a list of JS::Value
keys.
- For each key, call internal_get_own_property() to obtain a
descriptor and check `[[Enumerable]]`.
While that is required in the general case (e.g. for Proxy objects or
platform/exotic objects that override `[[OwnPropertyKeys]]`), it's
overkill for ordinary JS objects that store their own properties in the
shape table and indexed-properties storage.
This change introduces `for_each_own_property_with_enumerability()`,
which, for objects where
`eligible_for_own_property_enumeration_fast_path()` is `true`, lets us
read the enumerability directly from shape metadata (and from
indexed-properties storage) without a per-property descriptor lookup.
When we cannot avoid `internal_get_own_property()`, we still
benefit by skipping the temporary `Vector<Value>` of keys and avoiding
the unnecessary round-trip between PropertyKey and Value.
Previously, PutById constructed a PropertyKey from the identifier,
which coerced numeric-like strings to numbers. This moves that decision
to bytecode generation: the bytecode generator now emits PutByNumericId
for numeric keys and PutById for string keys. This removes per-execution
parsing from the interpreter.
1.4x speedup on the following microbenchmark:
```js
const o = {};
for (let i = 0; i < 10_000_000; i++) {
o.a = 1;
o.b = 2;
o.c = 3;
}
```
There apparently is a bit of a disconnect between the spec asking us to
construct the pattern using code points and LibRegex not being able to
swallow those. Whenever we had multi-byte code points in the pattern and
tried to match that in unicode mode, we would fail.
Change the parser to encode all non-ASCII code units. Fixes 2 test262
cases in `language/literals/regexp`.
...by avoiding `CreateListFromArrayLike` in cases when we could directly
use elements of underlying object's indexed properties storage.
Makes this program go 2.1x faster:
```js
function target(a, b, c) {
return a + b + c;
}
const args = [1, 2, 3];
let result = 0;
(function() {
for (let i = 0; i < 10_000_000; i++) {
result += target.apply(null, args);
}
})();
```
...when Array.prototype and Object.prototype are intact.
If `internal_set()` is called on an array exotic object with a numeric
PropertyKey, and:
- the prototype chain has not been modified (i.e., there are no getters
or setters for indexed properties), and
- the array is not the target of a Proxy object,
then we can directly store the value in the receiver's indexed
properties, without checking whether it already exists somewhere in the
prototype chain.
1.7x improvement on the following program:
```js
function f() {
let a = [];
let i = 0;
while (i < 10_000_000) {
a.push(i);
i++;
}
}
f();
```
We were previously unable to use simdutf for base64 decoding operations
other than "loose". Upstream has added support for the "strict" and
"stop-before-partial" operations, so let's make use of them!
Before, If the cache was empty we would try and evict non-existant
entries and crash. So the fix is to make sure that we don't saturate
the cache with a single parse result.
Before this change, we would enumerate all the keys with
[[OwnPropertyKeys]], and then do [[GetOwnPropertyDescriptor]] twice for
each key as we went through them.
We now only do one [[GetOwnPropertyDescriptor]] per key, which
drastically reduces the number of proxy traps when those are involved.
The new trap sequence matches what you get with V8, so I don't think
anyone will be unpleasantly surprised here.
This is a normative change in the ECMA-402 spec. See:
7508197
In our implementation, we don't have the affected AOs directly, as we
delegate to ICU. So instead, we must ensure we provide ICU a locale with
the relevant extension keys present.
