This uses ICU for the Intl.DateTimeFormat `format` `formatToParts`,
`formatRange`, and `formatRangeToParts`.
This lets us remove most data from our date-time format generator. All
that remains are time zone data and locale week info, which are relied
upon still for other interfaces. So they will be removed in a future
patch.
Note: All of the changes to the test files in this patch are now aligned
with other browsers. This includes:
* Some very incorrect formatting of Japanese symbols. (Looking at the
old results now, it's very obvious they were wrong.)
* Old FIXMEs regarding range formatting not including the start/end date
when only time fields were requested, but the dates differ.
* Day period inconsistencies.
Properties marked with the [[Unimplemented]] attribute behave as normal
but invoke the `VM::on_unimplemented_property_access callback` when
they are accessed.
The IntlMV is meant to be arbitrarily precise. If the user provides a
string value to be formatted, we lose precision by converting extremely
large values to a double. We were never able to address this, as support
for arbitrary precision was a big FIXME. But ICU can handle it by just
passing the raw string on through.
This uses ICU for the Intl.NumberFormat `formatRange` and
`formatRangeToParts` prototypes.
Note: All of the changes to the test files in this patch are now aligned
with both Chrome and Safari.
This uses ICU for the Intl.NumberFormat `format` and `formatToParts`
prototypes. It does not yet port the range formatter prototypes.
Most of the new code in LibLocale/NumberFormat is simply mapping from
ECMA-402 types to ICU types. Beyond that, the only algorithmic change is
that we have to mutate the output from ICU for `formatToParts` to match
what is expected by ECMA-402. This is explained in NumberFormat.cpp in
`flatten_partitions`.
This lets us remove most data from our number format generator. All that
remains are numbering system digits and symbols, which are relied upon
still for other interfaces (e.g. Intl.DateTimeFormat). So they will be
removed in a future patch.
Note: All of the changes to the test files in this patch are now aligned
with both Chrome and Safari.
Note: We keep locale parsing and syntactic validation as-is. ECMA-402
places additional restrictions on locales above what is required by the
Unicode spec. ICU doesn't provide methods that let us easily check those
restrictions, whereas LibLocale does. Other browsers also implement
their own validators here.
This introduces a locale cache to re-use parsed locale data and various
related structures (not doing so has a non-negligible performance impact
on Intl tests).
The existing APIs for canonicalization and display names are pretty
intertwined, so they must both be adapted at once here. The results of
canonicalization are slightly different on some edge cases. But the
changed results are actually now aligned with Chrome and Safari.
...that maintains a list of allocated execution contexts so malloc()
does not have to be called every time we need to get a new one.
20% improvement in Octane/typescript.js
16% improvement in Kraken/imaging-darkroom.js
By using separate struct we can avoid updating AST node and
ECMAScriptFunctionObject constructors every time there is a need to
add or remove some additional information colllected during parsing.
Allows to skip function environment allocation for non-arrow functions
if the only reason it is needed is to hold `this` binding.
The parser is changed to do following:
- If a function is an arrow function and uses `this` then all functions
in a scope chain are marked to allocate function environment for
`this` binding.
- If a function uses `new.target` then all functions in a scope chain
are marked to allocate function environment.
`ordinary_call_bind_this()` is changed to put `this` value in execution
context when function environment allocation is skipped.
35% improvement in Octane/typescript.js
50% improvement in Octane/deltablue.js
19% improvement in Octane/raytrace.js
This allows us to skip allocating a function environment in cases where
it was previously impossible because the arguments object needed a
binding.
This change does not bring visible improvement in Kraken or Octane
benchmarks but seems useful to have anyway.
This means that SetVariable instructions will now remember which
(relative) environment contains the targeted binding, letting it bypass
the full binding resolution machinery on subsequent accesses.
Merging registers, constants and locals into single vector means:
- Better data locality
- No need to check type in Interpreter::get() and Interpreter::set()
which are very hot functions
Performance improvement is visible in almost all Octane and Kraken
tests.
Filling a typed array with an integer shouldn't have to go through the
generic Set for every element.
This knocks a 7% item down to <1% in profiles of Another World JS at
https://cyxx.github.io/another_js/
Instead, generate bytecode to execute their AST nodes and save the
resulting operands inside the NewClass instruction.
Moving property expression evaluation to happen before NewClass
execution also moves along creation of new private environment and
its population with private members (private members should be visible
during property evaluation).
Before:
- NewClass
After:
- CreatePrivateEnvironment
- AddPrivateName
- ...
- AddPrivateName
- NewClass
- LeavePrivateEnvironment
Instead of relying on native stack overflows to kick us out of circular
proxy chains, we now keep track of the recursion depth and kick
ourselves out if it exceeds 10'000.
This fixes an issue where compiler tail/sibling call optimizations would
turn infinite recursion into infinite loops, and thus never hit a stack
overflow to kick itself out.
For whatever reason, we've only seen the issue on SerenityOS with UBSAN,
but it could theoretically happen on any platform.
By doing that all instructions required for instantiation are emitted
once in compilation and then reused for subsequent calls, instead of
running generic instantiation process for each call.
Instead of storing a full JS::Completion for the "throw completion"
case, we now store a simple JS::Value (wrapped in ErrorValue for the
type system).
This shrinks TCO<void> and TCO<Value> (the most common TCOs) by 8 bytes,
which has a non-trivial impact on performance.
In the common case, parseInt() is being called with strings that don't
have leading whitespace. By checking for that first, we can avoid the
cost of trimming and multiple malloc/GC allocations.
Instead of keeping bytecode as a set of disjoint basic blocks on the
malloc heap, bytecode is now a contiguous sequence of bytes(!)
The transformation happens at the end of Bytecode::Generator::generate()
and the only really hairy part is rerouting jump labels.
This required solving a few problems:
- The interpreter execution loop had to change quite a bit, since we
were storing BasicBlock pointers all over the place, and control
transfer was done by redirecting the interpreter's current block.
- Exception handlers & finalizers are now stored per-bytecode-range
in a side table in Executable.
- The interpreter now has a plain program counter instead of a stream
iterator. This actually makes error stack generation a bit nicer
since we just have to deal with a number instead of reaching into
the iterator.
This yields a 25% performance improvement on this microbenchmark:
for (let i = 0; i < 1_000_000; ++i) { }
But basically everything gets faster. :^)
If all lexical declaration use local variables then there is no need
to allocate declarative environment.
With this change we skip ~3x more environment allocations on Github.
We already had fast access to own properties via shape-based IC.
This patch extends the mechanism to properties on the prototype chain,
using the "validity cell" technique from V8.
- Prototype objects now have unique shape
- Each prototype has an associated PrototypeChainValidity
- When a prototype shape is mutated, every prototype shape "below" it
in any prototype chain is invalidated.
- Invalidation happens by marking the validity object as invalid,
and then replacing it with a new validity object.
- Property caches keep a pointer to the last seen valid validity.
If there is no validity, or the validity is invalid, the cache
misses and gets repopulated.
This is very helpful when using JavaScript to access DOM objects,
as we frequently have to traverse 4+ prototype objects before finding
the property we're interested in on e.g EventTarget or Node.
We can now tell the difference between an own property access and a
subsequent (automatic) prototype chain access.
This will be used to implement caching of prototype chain accesses.
