The sNPObjWrappers table can contain entries for dead JSObjects that have not yet been finalised. We need to take care not to trigger mJSObj's read barrier for such entries since that will attempt to expose the object to JS and cause this assertion.
The patch does this by calling unbarrieredGetPtr() which avoids the barrier.
Note converting a TenuredHeap to bool and testing equality against a pointer don't trigger the barrier.
It's silly to use prmem.h within Firefox code given that in our configuration
its functions are just wrappers for malloc() et al. (Indeed, in some places we
mix PR_Malloc() with free(), or malloc() with PR_Free().)
This patch removes all uses, except for the places where we need to use
PR_Free() to free something allocated by another NSPR function; in those cases
I've added a comment explaining which function did the allocation.
This patch makes the following changes to the macros.
- Removes PROFILER_LABEL_FUNC. It's only suitable for use in functions outside
classes, due to PROFILER_FUNCTION_NAME not getting class names, and it was
mostly misused.
- Removes PROFILER_FUNCTION_NAME. It's no longer used, and __func__ is
universally available now anyway.
- Combines the first two string literal arguments of PROFILER_LABEL and
PROFILER_LABEL_DYNAMIC into a single argument. There was no good reason for
them to be separate, and it forced a '::' in the label, which isn't always
appropriate. Also, the meaning of the "name_space" argument was interpreted
in an interesting variety of ways.
- Adds an "AUTO_" prefix to PROFILER_LABEL and PROFILER_LABEL_DYNAMIC, to make
it clearer they construct RAII objects rather than just being function calls.
(I myself have screwed up the scoping because of this in the past.)
- Fills in the 'js::ProfileEntry::Category::' qualifier within the macro, so
the caller doesn't need to. This makes a *lot* more of the uses fit onto a
single line.
The patch also makes the following changes to the macro uses (beyond those
required by the changes described above).
- Fixes a bunch of labels that had gotten out of sync with the name of the
class and/or function that encloses them.
- Removes a useless PROFILER_LABEL use within a trivial scope in
EventStateManager::DispatchMouseOrPointerEvent(). It clearly wasn't serving
any useful purpose. It also serves as extra evidence that the AUTO_ prefix is
a good idea.
- Tweaks DecodePool::SyncRunIf{Preferred,Possible} so that the labelling is
done within them, instead of at their callsites, because that's a more
standard way of doing things.
js::Class op are often all null. And when they're not all null, they're often
duplicated among classes. By pulling them out into their own struct, and using a
(possibly null) pointer in js::Class, we can save 114 KiB per process on
64-bit, and half that on 32-bit.
* * *
imported patch separate-ClassOps-2
js::ClassExtension is often all null. When it's not all null, it's often
duplicated among classes. By pulling it out into its own struct, and using a
(possibly null) pointer in js::Class, we can save 17 KiB per process on
64-bit, and half that on 32-bit.
js::ObjectOps is often all null. When it's not all null, it's often duplicated
many times among classes. By pulling it out into its own struct, and using a
(possibly null) pointer in js::Class, we can save 208 KiB per process on
64-bit, and half that on 32-bit.
The main change is that we move AutoJSExceptionReporter up to before the first
place where we might throw an exception, so we report those exceptions before
returning. The change to use AutoEntryScript consistently is because all of
these callsites can run JS in practice, and it seems reasonable to allow them
to.
