This meant that if some program threw an uncaught exception VM still
had unwind_until set. This caused any further programs to not execute
correctly.
This will be fixed more thoroughly once we use Completions in the AST.
Fixes#10323
This will be used by LibWeb to squirrel away the stack while performing
a microtask checkpoint in some cases. VM will simply consider saved
execution context stacks as GC roots as well.
It's very common to encounter single-character strings in JavaScript on
the web. We can make such strings significantly lighter by having a
1-character inline capacity on the Vectors.
The position is added to manually in the line terminator and Unicode
character cases. While it checks for EOF after doing so, the EOF check
used `!=` instead of `<`, meaning if the position went _over_ the
source length, it wouldn't think it was EOF and would cause read buffer
overflows.
For example, `0xea` followed by `0xfd` would cause this.
VM now has a string cache which tracks all live PrimitiveStrings and
reuses an existing one if possible. This drastically reduces the number
of GC-allocated strings in many real-word situations.
This is just factoring out step "9. Set O.[[Prototype]] to V." of
10.1.2 [[SetPrototypeOf]] into its own method so that we don't have to
use internal_set_prototype_of() for setting an object prototype in all
cases.
Prototypes can be set to null, and while the previous version also kinda
allowed null (by not reading through the null reference), it was making
UBSAN very sad.
The way that transition avoidance (foo_without_transition) was
implemented led to shapes being unshareable and caused shape explosion
instead, precisely what we were trying to avoid.
This patch removes all the attempts to avoid transitioning shapes, and
instead *adds* transitions when changing an object's prototype.
This makes transitions flow naturally, and as a result we end up with
way fewer shape objects in real-world situations.
When we run out of big problems, we can get back to avoiding transitions
as an optimization, but for now, let's avoid ballooning our processes
with a unique shape for every object.
Before this we used an ad-hoc combination of references and 'variables'
stored in a hashmap. This worked in most cases but is not spec like.
Additionally hoisting, dynamically naming functions and scope analysis
was not done properly.
This patch fixes all of that by:
- Implement BindingInitialization for destructuring assignment.
- Implementing a new ScopePusher which tracks the lexical and var
scoped declarations. This hoists functions to the top level if no
lexical declaration name overlaps. Furthermore we do checking of
redeclarations in the ScopePusher now requiring less checks all over
the place.
- Add methods for parsing the directives and statement lists instead
of having that code duplicated in multiple places. This allows
declarations to pushed to the appropriate scope more easily.
- Remove the non spec way of storing 'variables' in
DeclarativeEnvironment and make Reference follow the spec instead of
checking both the bindings and 'variables'.
- Remove all scoping related things from the Interpreter. And instead
use environments as specified by the spec. This also includes fixing
that NativeFunctions did not produce a valid FunctionEnvironment
which could cause issues with callbacks and eval. All
FunctionObjects now have a valid NewFunctionEnvironment
implementation.
- Remove execute_statements from Interpreter and instead use
ASTNode::execute everywhere this simplifies AST.cpp as you no longer
need to worry about which method to call.
- Make ScopeNodes setup their own environment. This uses four
different methods specified by the spec
{Block, Function, Eval, Global}DeclarationInstantiation with the
annexB extensions.
- Implement and use NamedEvaluation where specified.
Additionally there are fixes to things exposed by these changes to eval,
{for, for-in, for-of} loops and assignment.
Finally it also fixes some tests in test-js which where passing before
but not now that we have correct behavior :^).
Since there are only a number of statements where labels can actually be
used we now also only store labels when necessary.
Also now tracks the first continue usage of a label since this might not
be valid but that can only be determined after we have parsed the
statement.
Also ensures the correct error does not get wiped by load_state.
Since we have the to_reference method on every expression class we must
somehow communicate it did not actually return a reference.
This (ab)uses the fact that property name is only invalid with the
default constructor and already has is_valid().
The ECMAScript spec says that Date parsing can support any number of
implementation-defined date formats. So let's support a format commonly
used on the web. And let Core::DateTime do the heavy lifting. :^)
When we encounter a default clause in a switch statement, we should not
execute it immediately, instead we need to wait until all case clauses
have been executed as a matching case clause can break from the
switch/case.
The code is nowhere close to the spec, so instead of fixing it properly
I just made it slightly worse, but correct. Needs a complete refactor at
some point.
At a later point this will indicate whether some FunctionObject "has a
[[Construct]] internal method" (separate from the current FunctionObject
call() / construct()), to help with a more spec-compliant implementation
of [[Call]] and [[Construct]].
This means that it is no longer relevant to just NativeFunction.
