If a class field initializer is just a simple literal, we can skip
creating (and calling) a wrapper function for it entirely.
1.44x speedup on JetStream3/raytrace-private-class-fields.js
1.53x speedup on JetStream3/raytrace-public-class-fields.js
If we don't have parameter expressions, we don't need to collect
metadata about whether instantiated var names collide with parameter
names or function names, as these flags are only used in the parameter
code path.
This avoids going through all the shape transitions when setting up the
most common form of ESFO.
This is extremely hot on Uber Eats, and this provides some relief.
Instead of making a copy of the Vector<FunctionParameter> from the AST
every time we instantiate an ECMAScriptFunctionObject, we now keep the
parameters in a ref-counted FunctionParameters object.
This reduces memory usage, and also allows us to cache the bytecode
executables for default parameter expressions without recompiling them
for every instantiation. :^)
Currently, we create `this_argument` with
`ordinary_create_from_constructor`, then we use `arguments_list` to
build the callee_context.
The issue is we don't properly model the side-effects of
`ordinary_create_from_constructor`, if `new_target` is a proxy object
then when we `get` the prototype, arbitrary javascript can run.
This javascript could perform a function call with enough arguments to
reallocate the interpreters m_argument_values_buffer vector. This is
dangerous and leads to a use-after-free, as our stack frame maintains a
pointer to m_argument_values_buffer (`arguments_list`).
From what I understand, the suspension steps are not required now,
or in the future for our implementation, or any other. The intent
is already implemented in the spec pushing on another execution
context to the stack and leaving the running execution context as-is.
The resume steps are a slightly different story as there is some subtle
behavior which the spec is trying to convey where some custom logic may
need to be done when one execution context changes from one to another.
It may be worth implementing those steps at a later point in time so
that this behavior is a bit easier to follow in those cases.
To make the situation more confusing - from what I can gather from the
spec, not all cases that the spec mentions resume actually means
anything normative. Resume is only _actually_ needed in a limited set
of locations.
For now, let's just remove the unneeded FIXMEs that indicate that there
is something to be done for the suspension steps, as there is not, and
leave the resume steps as is.
`AsyncBlockStart` was still doing a `DisposeResources` call as
specified in older drafts of the `explicit-resource-management`
proposal, but the latest draft no longer does this, and it is
causing crashes when combined with the `array-from-async` proposal.
Resulting in a massive rename across almost everywhere! Alongside the
namespace change, we now have the following names:
* JS::NonnullGCPtr -> GC::Ref
* JS::GCPtr -> GC::Ptr
* JS::HeapFunction -> GC::Function
* JS::CellImpl -> GC::Cell
* JS::Handle -> GC::Root
The main motivation behind this is to remove JS specifics of the Realm
from the implementation of the Heap.
As a side effect of this change, this is a bit nicer to read than the
previous approach, and in my opinion, also makes it a little more clear
that this method is specific to a JavaScript Realm.
