By doing that we avoid doing separate allocation for each such vector,
which was really expensive on js heavy websites. For example this change
helps to get EC allocation down from ~17% to ~2% on Google Maps. This
comes at cost of adding extra complexity to custom execution context
allocator, because EC no longer has fixed size and we need to maintain
a list of buckets.
This is better because:
- Better data locality
- Allocate vector for registers+constants+locals+arguments in one go
instead of allocating two vectors separately
Fixes a bunch of websites breaking because we now verify jump offsets by
trying to remove 0-offset jumps.
This has been broken for a good while, it was just rare to see Repeat
inside alternatives that lended themselves well to tree alts.
The about:settings page has gotten beefy enough that it is a bit of a
paint to manage in a single HTML file. This patch breaks the settings
into several modules to make this page easier to mantain.
Modules have some nice benefits over classic scripts, such as enabling
strict mode by default, and allowing each module to function without
polluting the global object.
We had a bit of an awkward setup where we want the Application to be a
SettingsObserver, but neither the Settings object nor the Application
itself was fully initialized by the time the observer was created. So
we invented a deferred observer initializer specifically for the
Application.
Instead, let's just create a dedicated observer subclass that is owned
by the Application. We can then create it once we have the singleton
Application appropriately set up.
JavaScript module requests (in a non-worker context) always have CORS
enabled. However, CORS requests are only allowed for same-origin or
HTTP/S requests. This patch extends this to allow resource:// requests
from opaque origins (e.g. about: URLs).
We must also set the Access-Control-Allow-Origin header to "null" to
ensure that the response is accepted by the CORS checks. This does not
affect requesting resource:// URLs from resource:// URLs as those are
same-origin and skip CORS checks.
This ultimately enables requesting resource:// JS modules from the
about:settings page.
The special case for anonymous table wrappers actually ended up hurting
correctness by preventing the full ancestor chain from being marked for
for intrinsic size cache invalidation.
Caused Layout/input/table/propagate-style-update-to-wrapper.html to
flake on CI, and was easy to reproduce locally with sanitizers.
The fix here is simply to remove the special handling of anonymous table
wrapper parents, since *all* parents are invalidated automatically
anyway!
Began flaking in fa9c463ffd.
Previously we were counting the total number of *nodes* in the tree for
the chain cost, which greatly underestimated its cost when large
bytecode entries were present,
This commit switches to estimating it using the total bytecode *size*,
which is a closer value to the true cost than the tree node count.
This corresponds to a ~4x perf improvement on /<script|<style|<link/ in
speedometer.
Previously, if a transition property was not wrapped in a list, it
would be replaced with the default value in
`StyleComputer::compute_transitioned_properties`.
For the slight cost of counting code points when converting between
encodings and a teeny bit of memory, this commit adds a fast path for
all-happy utf-16 substrings and code point operations.
This seems to be a significant chunk of time spent in many regex
benchmarks.
