This makes the behavior of `Symbol` correct in strict mode, wherein if
the receiver is a symbol primitive, assigning new properties should
throw a TypeError.
This avoids the overhead of allocating a new Array on every function
call, saving a substantial amount of time and avoiding GC thrash.
This patch only makes use of Op::Call in CallExpression. There are other
places we should codegen this op. We should also do the same for super
expression calls.
~5% speed-up on Kraken/stanford-crypto-ccm.js
Forcing every function call to allocate a new Array just to accommodate
spread parameters is not very nice, so let's start moving towards making
this a special case rather than the general (and only) case.
This makes them trivially copyable, which is an assumption multiple
optimizations use when rebuilding the instruction stream.
This fixes most optimized crashes in the test262 suite.
This is in preparation for an upcoming implementation of the Iterator
Helpers proposal. That proposal will require a JS::Object type named
"Iterator", so this rename is to avoid conflicts.
The fact that side effects clobbers the accumulator isn't just annoying
inside the instruction handler, but also really counter-intuitive in
the bytecode program itself.
17 new passes on test262. :^)
Instead of assuming that there's an active AST interpreter, this code
now takes VM& everywhere and invokes the appropriate interpreter.
92 new passes on test262. :^)
The JS::VM now owns the one Bytecode::Interpreter. We no longer have
multiple bytecode interpreters, and there is no concept of a "current"
bytecode interpreter.
If you ask for VM::bytecode_interpreter_if_exists(), it will return null
if we're not running the program in "bytecode enabled" mode.
If you ask for VM::bytecode_interpreter(), it will return a bytecode
interpreter in all modes. This is used for situations where even the AST
interpreter switches to bytecode mode (generators, etc.)
Many operations in JavaScript may incur side effects, including calling
arbitrary user code. Since the user code will clobber the accumulator,
we have to take care to extract anything we need from the accumulator
before doing anything that may have side effects.
Fixes 3 test262 tests. :^)
The fix for this was to port the "don't create unnecessary FooObject
for property access on primitives" optimization from Reference,
which also brings us the correct behavior.
Since we no longer need to create or leave var environments directly
in bytecode, we can streamline the two instructions by making them
always operate on the lexical environment.
Instead of implementing this AO in bytecode, we now have an instruction
for it that simply invokes the C++ implementation.
This allows us to simplify Bytecode::Generator quite a bit by removing
all the variable scope tracking.
We use generators in bytecode to approximate async functions, but the
code generated by AwaitExpressions did not have the value processing
paths that Yield requires, eg the `generator.throw()` path, which is
used by AsyncFunctionDriverWrapper to signal Promise rejections.
This uses a newly added instruction `ScheduleJump`
This instruction tells the finally proceeding it, that instead of
jumping to it's next block it should jump to the designated block.
This includes an Error::create overload to create an Error from a UTF-8
StringView. If creating a String from that view fails, the factory will
return an OOM InternalError instead. VM::throw_completion can also make
use of this overload via its perfect forwarding.
First, this adds an overload of PrimitiveString::create for StringView.
This overload will throw an OOM completion if creating a String fails.
This is not only a bit more convenient, but it also ensures at compile
time that all PrimitiveString::create(string_view) invocations will be
handled as String and OOM-aware.
Next, this wraps all invocations to PrimitiveString::create(string_view)
with MUST_OR_THROW_OOM.
A small PrimitiveString::create(DeprecatedFlyString) overload also had
to be added to disambiguate between the StringView and DeprecatedString
overloads.
