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.
The valid range for temporal values (`nsMinInstant`/`nsMaxInstant`)
means performing nanosecond-valued integers could lead to an overflow.
NB: Only the `roundingMode: "day"` case was affected, as all others were
already performing the division on floating-point `fractional_second`
values. I'm adding `.0` suffixes everywhere to make this fact clearer.
This adds a few local tests as well, as those are tested with sanitizers
enabled by default, unlike test262.
This constructor was easily confused with a copy constructor, and it was
possible to accidentally copy-construct Objects in at least one way that
we dicovered (via generic ThrowCompletionOr construction).
This patch adds a mandatory ConstructWithPrototypeTag parameter to the
constructor to disambiguate it.
We have a new, improved string type coming up in AK (OOM aware, no null
state), and while it's going to use UTF-8, the name UTF8String is a
mouthful - so let's free up the String name by renaming the existing
class.
Making the old one have an annoying name will hopefully also help with
quick adoption :^)
Intrinsics, i.e. mostly constructor and prototype objects, but also
things like empty and new object shape now live on a new heap-allocated
JS::Intrinsics object, thus completing the long journey of taking all
the magic away from the global object.
This represents the Realm's [[Intrinsics]] slot in the spec and matches
its existing [[GlobalObject]] / [[GlobalEnv]] slots in terms of
architecture.
In the majority of cases it should now be possibly to fully allocate a
regular object without the global object existing, and in fact that's
what we do now - the realm is allocated before the global object, and
the intrinsics between both :^)
- Prefer VM::current_realm() over GlobalObject::associated_realm()
- Prefer VM::heap() over GlobalObject::heap()
- Prefer Cell::vm() over Cell::global_object()
- Prefer Wrapper::vm() over Wrapper::global_object()
- Inline Realm::global_object() calls used to access intrinsics as they
will later perform a direct lookup without going through the global
object
This is a continuation of the previous five commits.
A first big step into the direction of no longer having to pass a realm
(or currently, a global object) trough layers upon layers of AOs!
Unlike the create() APIs we can safely assume that this is only ever
called when a running execution context and therefore current realm
exists. If not, you can always manually allocate the Error and put it in
a Completion :^)
In the spec, throw exceptions implicitly use the current realm's
intrinsics as well: https://tc39.es/ecma262/#sec-throw-an-exception
This is an editorial change in the ECMA-262 and Temporal specs.
See:
- 843d8b8
- f9211d9
Note that we don't actually need to implement the AO as we already have
String::formatted() for this, and use unified format strings instead of
zero-padding in individual steps in many cases anyway.
This is an editorial change in the Temporal spec.
See:
- 7fbdd28
- f666243
- 8c7d066
- 307d108
- d9ca402
In practical terms this means we can now get rid of a couple of awkward
assertion steps that were no-ops anyway, since the types are enforced
by the compiler.
This is an editorial change in the Temporal spec.
See: 983902e
We already had these defined as structs, but now they're properly
defined in the spec (opposed to the previous anonymous records), and we
don't have to make up our own names anymore :^)
Note that while we're usually not including 'record' in the name, in
this case the 'Duration Record' has a name clash with the Duration
object. Additionally, later editorial changes introduce CreateFooRecord
AOs, so let's just go with FooRecord structs here.
