This greatly reduces the number of compilations necessary when functions
declaring local functions are re-executed.
For example Octane/typescript.js goes from 58080 bytecode executables
to 960.
This patch adds two macros to declare per-type allocators:
- JS_DECLARE_ALLOCATOR(TypeName)
- JS_DEFINE_ALLOCATOR(TypeName)
When used, they add a type-specific CellAllocator that the Heap will
delegate allocation requests to.
The result of this is that GC objects of the same type always end up
within the same HeapBlock, drastically reducing the ability to perform
type confusion attacks.
It also improves HeapBlock utilization, since each block now has cells
sized exactly to the type used within that block. (Previously we only
had a handful of block sizes available, and most GC allocations ended
up with a large amount of slack in their tails.)
There is a small performance hit from this, but I'm sure we can make
up for it elsewhere.
Note that the old size-based allocators still exist, and we fall back
to them for any type that doesn't have its own CellAllocator.
Array.length is magical (since it has to reflect the number of elements
in the object's property storage).
We now handle it specially in jitted code, giving us a massive speed-up
on Kraken/ai-astar.js (and probably many other things as well) :^)
This patch makes it possible for JS::Object::internal_set() to populate
a CacheablePropertyMetadata, and uses this to implement a basic
monomorphic cache for the most common form of property write access.
Normally, we want to avoid accidentally using such atomics, since
they're much slower. In this case however, we're just implementing
another atomics API, it is then up to the JavaScript code to avoid
using the slow atomics.
We currently cannot parse the output of `toString` and `toUTCString`.
While the spec does not require such support, test262 expects it, and
all major engines support it.
Since 2023-09-08, Clang trunk has had a bug which causes a segfault when
evaluating certain `requires` expressions inside templated lambdas.
There isn't an imminent fix on the horizon, so let's work around the
issue by specifying the type of the offending lambda arguments
explicitly.
See https://github.com/llvm/llvm-project/issues/67260
We were trying to stringify the stack trace without the last element,
leading to a loop bound of (size_t)(0 - 1) and accessing m_traceback[0]
out-of-bounds.
Instead, just return an empty string in that case.
Fixes#21747
The previous implementation was calling `backtrace()` for every
function call, which is quite slow.
Instead, this implementation provides VM::stack_trace() which unwinds
the native stack, maps it through NativeExecutable::get_source_range
and combines it with source ranges from interpreted call frames.
Previously these handlers duplicated code and used formats that
were different from the one Error.prototype.stack uses.
Now they use the same Error::stack_string function, which accepts
a new parameter for compacting stack traces with repeating frames.
This patch updates various parts of the script fetching implementation
to match the current specification.
Notably, the implementation of changes to the import assertions /
attributes proposal are not part of this patch(series).
As of https://tc39.es/ecma262/#sec-yearfromtime, YearFromTime(t) should
return `y` such that `TimeFromYear(YearFromTime(t)) <= t`. This wasn't
held, since the approximation contained decimal digits that would nudge
the final value in the wrong direction.
Adapted from Kiesel:
6548a85743
Co-authored-by: Linus Groh <mail@linusgroh.de>
The spec asks us to perform some calculations that quickly exceed an
`u64`, but instead of jumping through hoops we can rely on our AK
implementation of floating point formatting to come up with the
correctly rounded result.
Note that most other JS engines seem to diverge from the spec as well
and fall back to a generic dtoa path.
This commit removes DeprecatedString's "null" state, and replaces all
its users with one of the following:
- A normal, empty DeprecatedString
- Optional<DeprecatedString>
Note that null states of DeprecatedFlyString/StringView/etc are *not*
affected by this commit. However, DeprecatedString::empty() is now
considered equal to a null StringView.
These functions all have a very common case that can be dealt with a
very simple inline check, often avoiding the need to call an out-of-line
function. This patch moves the common case to inline functions in a new
ValueInlines.h header (necessary due to header dependency issues..)
8% speed-up on the entire Kraken benchmark :^)
