WeakContainers need to look at the Cell::State bits to know if their
weak pointees got swept by garbage collection. So we must do this before
potentially freeing one or more HeapBlocks by notifying the allocator
that a block became empty.
This commit partially reverts "LibJS: Make accessing the current
function's arguments cheaper".
While the change passed all the currently passing test262 tests, it
seems to have _some_ flaw that silently breaks with some real-world
websites.
As the speedup with negligible at best, let's just revert it until we
can implement it more correctly.
By spec, calling an ECMAScript function object in non-strict mode should
always create a new top-level declarative environment, even if there are
no lexically scoped bindings (let/const) that belong in it. This is
used for scope disambiguation in direct eval() calls.
However, if there are no direct eval() calls within the function, and no
lexically scoped bindings, we can simply not allocate the extra
environment and save ourselves the trouble.
We now propagate this flag to FunctionDeclaration, and then also into
ECMAScriptFunctionObject.
This will be used to disable optimizations that aren't safe in the
presence of direct eval().
Instead of going through an environment record, make arguments of the
currently executing function generate references via the argument index,
which can later be resolved directly through the ExecutionContext.
Both my approach and the previous approach were wrong for different
cases. I've changed the Iterators index from storage-relative to
queue-relative, and it's much simpler and more obviously correct.
fixes#10383
The recursive style update function was written a bit strangely and
would only mark descendants of the style update root as not needing a
style update.
With this patch, all nodes in the subtree now have clean style after a
style update finishes.
Layout depends on style (and not the other way around), so if the
document has dirty style when we enter update_layout(), make sure we
call update_style() before proceeding with the layout work.
This has the pleasant effect of coalescing some redundant layouts.
This was a nice idea in theory, but in practice it makes big crashes
(e.g WebContent) even more CPU intensive. Let's disable this for now
(but keep the ability for CrashReporter to open compressed coredumps.)
While I was working on LibWeb, I got a page fault at 0xe0e0e0e4.
This indicates a destroyed RefPtr if compiled with SANITIZE_PTRS
defined. However, the page fault handler didn't print out this
indication.
This makes the page fault handler print out a note if the faulting
address looks like a recently destroyed RefPtr, OwnPtr, NonnullRefPtr,
NonnullOwnPtr, ThreadSafeRefPtr or ThreadSafeNonnullRefPtr. It will
only do this if SANITIZE_PTRS is defined, as smart pointers don't get
scrubbed without it being defined.
This exposes a small subset of the information exposed by the Linux
equivalent, and will be used to optimize applications that would like
to know the current CPU usage statistics, but don't want to read all of
the unrelated information in /proc/all
Some time ago, automatic locking was added to the AK smart pointers to
paper over various race conditions in the kernel. Until we've actually
solved the issues in the kernel, we're stuck with the locking.
However, we don't need to punish single-threaded userspace programs with
the high cost of locking. This patch moves the thread-safe variants of
RefPtr, NonnullRefPtr, WeakPtr and RefCounted into Kernel/Library/.
It's "Clang" (capitalized). Silently building gcc if the toolchain
isn't know seems a bit unfriendly. So print a warning for this
(and for other unknown toolchains).
Unlike the spec we chose BigInt for the input and output types here as
it was being used with ℝ(ns), ns being of type BigInt, in one place and
a conversion to double would not be safe.
Since in many places we'll have double input values, let's add a double
overload of this function to avoid awkward conversions and expensive
allocations.
This patch introduces the "environment coordinate" concept, which
encodes the distance from a variable access to the binding it ends up
resolving to.
EnvironmentCoordinate has two fields:
- hops: The number of hops up the lexical environment chain we have
to make before getting to the resolved binding.
- index: The index of the resolved binding within its declarative
environment record.
Whenever a variable lookup resolves somewhere inside a declarative
environment, we now cache the coordinates and reuse them in subsequent
lookups. This is achieved via a coordinate cache in JS::Identifier.
Note that non-strict direct eval() breaks this optimization and so it
will not be performed if the resolved environment has been permanently
screwed by eval().
This makes variable access *significantly* faster. :^)
Since non-strict direct eval() can insert new bindings into a
surrounding var scope, we cannot safely cache some assumptions about
environment chain layout after eval() has taken place.
Since eval() is rare, let's do what other engines do and simply
deoptimize in its presence. This patch adds a new "permanently screwed"
flag to JS::Environment that will be set on the entire variable
environment chain upon non-strict direct eval().
This commit introduces the main infrastructure used for turning register
values into user-facing values that can be printed by strace. This
includes the ability to copy data from a particular memory address in
the traced process. On top of this, (partial) formatting has been added
for the most common I/O operations (open, read, write, lseek, close,
stat, fstat).
Moving the formatting of strace's output into a separate function will
allow us to introduce more complexity into the formatting logic without
touching the main body of the program.
The new function uses a switch statement to select how to format the
arguments and result depending on the syscall. At this point we only
include the default formatting, where the registers are simply dumped,
but later on we can add specializations for each system call we want to
support.
