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LibJS: Make array-like Get access on ordinary objects much faster

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This patch adds a fast path to the GetByValue bytecode op that bypasses
a ton of things *if* a set of assumptions hold:

- The property key must be a non-negative Int32
- The base object must not interfere with indexed property access
- The property key must already be present as an own property
- The existing value must not have any accessors defined

If this holds (which it should in the common case), we can poke directly
at the indexed property storage and save a boatload of time.

10% speed-up on the entire Kraken benchmark :^)
(including: 31% speed-up on Kraken/audio-dft.js)
(including: 23% speed-up on Kraken/stanford-crypto-aes.js)
This commit is contained in:
Andreas Kling 2023-10-05 09:00:54 +02:00
parent a3ee8ff377
commit 27a83f7e5e
1 changed files with 13 additions and 0 deletions
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13
Userland/Libraries/LibJS/Bytecode/Interpreter.cpp
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@ -1530,6 +1530,19 @@ ThrowCompletionOr<void> GetByValue::execute_impl(Bytecode::Interpreter& interpre
auto base_value = interpreter.reg(m_base);
auto object = TRY(base_object_for_get(interpreter, base_value));
// OPTIMIZATION: Fast path for simple Int32 indexes in array-like objects.
if (property_key_value.is_int32()
&& property_key_value.as_i32() >= 0
&& !object->may_interfere_with_indexed_property_access()
&& object->indexed_properties().has_index(property_key_value.as_i32())) {
auto value = object->indexed_properties().get(property_key_value.as_i32())->value;
if (!value.is_accessor()) {
interpreter.accumulator() = value;
return {};
}
}
auto property_key = TRY(property_key_value.to_property_key(vm));
if (base_value.is_string()) {