This commit un-deprecates DeprecatedString, and repurposes it as a byte
string.
As the null state has already been removed, there are no other
particularly hairy blockers in repurposing this type as a byte string
(what it _really_ is).
This commit is auto-generated:
$ xs=$(ack -l \bDeprecatedString\b\|deprecated_string AK Userland \
Meta Ports Ladybird Tests Kernel)
$ perl -pie 's/\bDeprecatedString\b/ByteString/g;
s/deprecated_string/byte_string/g' $xs
$ clang-format --style=file -i \
$(git diff --name-only | grep \.cpp\|\.h)
$ gn format $(git ls-files '*.gn' '*.gni')
For now, we handle this by creating a synthetic async function to wrap
the top-level module code. This allows us to piggyback on the async
function driver wrapper mechanism.
This required setting things up so that all function objects can plop
a PrimitiveString there instead of an AK string.
This is a step towards making ExecutionContext easier to allocate.
(Instead of MarkedVector<Value>.) This is a step towards not storing
argument lists in MarkedVector<Value> at all. Note that they still end
up in MarkedVectors since that's what ExecutionContext has.
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.
We can use `ensure_capacity` for binding vectors if we know their sizes
in advance. This ensures that binding vectors aren't reallocated during
the `function_declaration_instantiation` execution.
With this change, `try_grow_capacity()` and `shrink_to_fit()` are no
longer visible in the `function_declaration_instantiation()` profiles
when running React-Redux-TodoMVC from Speedometer.
This change moves steps that can be executed only once and then reused
in subsequent function instantiations from
`function_declaration_instantiation` to the ECMAScriptFunctionObject:
- Determine if there are any parameters with duplicate names.
- Determine if there are any parameters with expressions.
- Determine if an arguments object needs to be created.
- Create a list of distinct function names for which bindings need to
be created.
- Create a list of distinct variable names for which bindings need to
be created.
This change makes React-Redux-TodoMVC test in Speedometer
run 10% faster :)
Saving vector of local variables names in ECMAScriptFunctionObject
will allow to get a name by index in case message of ReferenceError
needs to contain a variable name.
Note that as of this commit, there aren't any such throwers, and the
call site in Heap::allocate will drop exceptions on the floor. This
commit only serves to change the declaration of the overrides, make sure
they return an empty value, and to propagate OOM errors frm their base
initialize invocations.
DeprecatedFlyString relies heavily on DeprecatedString's StringImpl, so
let's rename it to A) match the name of DeprecatedString, B) write a new
FlyString class that is tied to String.
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 :^)
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 is a continuation of the previous commit.
Calling initialize() is the first thing that's done after allocating a
cell on the JS heap - and in the common case of allocating an object,
that's where properties are assigned and intrinsics occasionally
accessed.
Since those are supposed to live on the realm eventually, this is
another step into that direction.
This was defined twice, despite being the very same thing:
- ClassElement::ClassFieldDefinition
- ECMAScriptFunctionObject::InstanceField
Move the former to a new header and use it everywhere. Also update the
define_field() AO to take a single field instead of separate name and
initializer arguments.
While adding spec comments to PerformEval, I noticed we were missing
multiple steps.
Namely, these were:
- Checking if the host will allow us to compile the string
(allowing LibWeb to perform CSP for eval)
- The parser's initial state depending on the environment around us
on direct eval:
- Allowing new.target via eval in functions
- Allowing super calls and super properties via eval in classes
- Disallowing the use of the arguments object in class field
initializers at eval's parse time
- Setting ScriptOrModule of eval's execution context
The spec allows us to apply the additional parsing steps in any order.
The method I have gone with is passing in a struct to the parser's
constructor, which overrides the parser's initial state to (dis)allow
the things stated above from the get-go.
The environment settings object is effectively the context a piece of
script is running under, for example, it contains the origin,
responsible document, realm, global object and event loop for the
current context. This effectively replaces ScriptExecutionContext, but
it cannot be removed in this commit as EventTarget still depends on it.
https://html.spec.whatwg.org/multipage/webappapis.html#environment-settings-object
Using an Optional was extremely wasteful for function objects that don't
even have a bytecode executable.
This allows ECMAScriptFunctionObject to fit in a smaller size class.
This should have been the default as it roughly represents the
OrdinaryFunctionCreate AO.
For now, keep two overloads and continue to guess the required prototype
from the function kind in most cases. The prototype needs to be passed
in explicitly when it may be derived from user code, such as in the
CreateDynamicFunction AO.
This is now as defined in the spec. However since we execute async
functions in bytecode by transforming it to a generator function it must
have a prototype for the GeneratorObject. We check whether it is an
async function and in that case use the hardcoded generator object
prototype. This also ensures that user code cannot override this
property thus preventing exposing internal implementation details.
This commit adds support for the most bare bones version of async
functions, support for async generator functions, async arrow functions
and await expressions are TODO.
