This is a continuation of the previous six commits.
The global object is only needed to return it if the execution context
stack is empty, but that doesn't seem like a useful thing to allow in
the first place - if you're not currently executing JS, and the
execution context stack is empty, there is no this value to retrieve.
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 a continuation of the previous four commits.
Passing a global object here is largely redundant, we definitely need
the interpreter but can get the VM and (later) current active realm from
there - and also the global object while we still need it, although I'd
like to remove Interpreter::global_object() in the future.
This now matches the bytecode interpreter's execute_impl() functions.
This is a continuation of the previous three commits.
Now that create() receives the allocating realm, we can simply forward
that to allocate(), which accounts for the majority of these changes.
Additionally, we can get rid of the realm_from_global_object() in one
place, with one more remaining in VM::throw_completion().
This is a continuation of the previous two commits.
As allocating a JS cell already primarily involves a realm instead of a
global object, and we'll need to pass one to the allocate() function
itself eventually (it's bridged via the global object right now), the
create() functions need to receive a realm as well.
The plan is for this to be the highest-level function that actually
receives a realm and passes it around, AOs on an even higher level will
use the "current realm" concept via VM::current_realm() as that's what
the spec assumes; passing around realms (or global objects, for that
matter) on higher AO levels is pointless and unlike for allocating
individual objects, which may happen outside of regular JS execution, we
don't need control over the specific realm that is being used there.
This prevents us from needing a sv suffix, and potentially reduces the
need to run generic code for a single character (as contains,
starts_with, ends_with etc. for a char will be just a length and
equality check).
No functional changes.
Each of these strings would previously rely on StringView's char const*
constructor overload, which would call __builtin_strlen on the string.
Since we now have operator ""sv, we can replace these with much simpler
versions. This opens the door to being able to remove
StringView(char const*).
No functional changes.
Previously it would pass in `is_arrow_function` as
`contains_direct_call_to_eval`, which broke strict mode propagation in
arrow functions. This makes test-js work without falling apart because
`this` is mysteriously undefined because of the use of arrow functions
inside classes, which are strict mode by default.
`delete` has to operate directly on Reference Records, so this
introduces a new set of operations called DeleteByValue, DeleteVariable
and DeleteById. They operate similarly to their Get counterparts,
except they end in creating a (temporary) Reference and calling delete_
on it.
NewArray now only contains two elements maximum in `m_elements` to
indicate the range of registers to create the array from.
However, `m_element_count` still contains how many registers are in the
range and the stringifier was not updated to account for this. Thus, if
the range contained more than 2 registers, it would do a read OOB on
`m_elements`.
This makes it now just print the first and second entries in
`m_elements` in the format of `[<reg>-<reg>]`.
Listing all the registers will lead to the inability to allocate enough
space in one basic block (as there can be an arbitrary number of
registers used), instead switch to specifying the range of registers
used and save a lot of space in the process.
This follows how the regular AST interpreter creates arrays, as using
Array::create_from uses create_data_property_or_throw, which will crash
when it encounters an empty value. We require empty values to represent
array holes.
This was not handling the nullary call case correctly, remove the whole
nullary check as there's nothing particularly expensive in the catch-all
case anyway.
Now we emit CreateVariable and SetVariable with the appropriate
initialization/environment modes, much closer to the spec.
This makes a whole lot of things like let/const variables, function
and variable hoisting and some other things work :^)
Instead of using plain objects as Iterator records, causes confusion
about the object itself actually being its [[Iterator]] slot, and
requires non-standard type conversion shenanigans fpr the [[NextValue]]
and [[Done]] internal slots, implement a proper Iterator record struct
and use it throughout.
Also annotate the remaining Iterator AOs with spec comments while we're
here.
This is another major milestone on our journey towards removing global
VM exception state :^)
Does pretty much exactly what it says on the tin: updating
ASTNode::execute() to return a Completion instead of a plain value. This
will *also* allow us to eventually remove the non-standard unwinding
mechanism and purely rely on the various completion types.
In the end this is a nicer API than having separate has_{value,target}()
and having to check those first, and then making another Optional from
the unwrapped value:
completion.has_value() ? completion.value() : Optional<Value> {}
// ^^^^^^^^^^^^^^^^^^
// Implicit creation of non-empty Optional<Value>
This way we need to unwrap the optional ourselves, but can easily pass
it to something else as well.
This is in anticipation of the AST using completions :^)
The spec has a note stating that resolve binding will always return a
reference whose [[ReferencedName]] field is name. However this is not
correct as the underlying method GetIdentifierReference may throw on
env.HasBinding(name) thus it can throw. However, there are some
scenarios where it cannot throw because the reference is known to exist
in that case we use MUST with a comment.
This is a specialized string table for storing identifiers only.
Identifiers are always FlyStrings, which makes many common operations
faster by allowing O(1) comparison.
