For the common use case of having a single resolve or reject callback,
the callbacks are stored directly. Only when an additional callback is
registered, we create an array to store these callbacks.
There are 3 possible states for the resolve, reject symbols when we add
a new callback --
1) UNDEFINED -- This is the zero state where there is no callback
registered. When we see this state, we directly attach the callbacks to
the symbol.
2) !IS_ARRAY -- There is a single callback directly attached to the
symbols. We need to create a new array to store additional callbacks.
3) IS_ARRAY -- There are multiple callbacks already registered,
therefore we can just push the new callback to the existing array.
Also, this change creates a new symbol for storing the deferred objects.
Previously the deferred objects were stored in the callback arrays, but
since we no longer create arrays for the initial case, we need this new
symbol. The cctest has been updated to account for this new symbol.
This patch results in a 19% improvement(over 5 runs) in the bluebird benchmark.
BUG=v8:5046
Review-Url: https://codereview.chromium.org/2007803002
Cr-Commit-Position: refs/heads/master@{#36536}
String wrappers (new String("foo")) are special objects: their string
characters are accessed like elements, and they also have an elements
backing store. This used to require a bunch of explicit checks like:
if (obj->IsJSValue() && JSValue::cast(obj)->value()->IsString()) {
/* Handle string characters */
}
// Handle regular elements (for string wrappers and other objects)
obj->GetElementsAccessor()->Whatever(...);
This CL introduces new ElementsKinds for string wrapper objects (one for
fast elements, one for dictionary elements), which allow folding the
special-casing into new StringWrapperElementsAccessors.
No observable change in behavior is intended.
Review URL: https://codereview.chromium.org/1612323003
Cr-Commit-Position: refs/heads/master@{#33616}
The test expectations should fail consistently in both release and debug
builds. DCHECK is only meant for debug-only checks in production code.
R=yangguo@chromium.org
Review URL: https://codereview.chromium.org/1506753002
Cr-Commit-Position: refs/heads/master@{#32639}
It didn't support subclassing case at all and in non-subclassing case the runtime
allocation didn't do the slack tracking step.
BUG=chromium:563339
LOG=Y
Review URL: https://codereview.chromium.org/1488023002
Cr-Commit-Position: refs/heads/master@{#32547}
