ArrayData gets on a diet, down to 32 bytes
devirtualized destructor call in HphpArray::release()
aggressively inlined constructors for ArrayData (do away with defaulted arguments)
eliminate a dead memset() for the hashtable in HphpArray(uint size, const TypedValue* values)
I've run a bunch of experiments on HphpArray speed and am still yet to have a major breakthrough. However, there are a few clear small winners that I'm submitting with this diff. CPU instructions, CPU loads, and CPU stores are all as green as the Eternal Hunting Grounds. Speed is drowned in noise but I sususpect will be measurable on these changes combined.
I was learning from @jdelong and he said that you should use
double quotes for local includes and angle brackets for library
includes. I asked why our code was the way it was, and he said he wanted
to clean it up. I beat him to it :)
Conflicts:
hphp/runtime/base/server/admin_request_handler.cpp
hphp/runtime/vm/named_entity.h
Streamline the array access methods by always returning an array
pointer instead of a new pointer or null. Callsites compare
(new != old) to detect escalation, rather than (new != null).
Replaces the awkward getFullPos() and setFullPos() methods with a more
intuitive advanceFullPos() method. This refactoring also reduces the number
of virtual calls made when doing mutable iteration on an array.
This diff refactors some of the VM's logic for iterators (with a focus on
mutable iteration), delivering several improvements:
1) MIterCtx was renamed to MArrayIter, and the m_key and m_val fields
were eliminated.
2) Eliminated the need for MArrayIter to dynamically allocate a
MutableArrayIter object, and removed other layers of indirection as
well.
3) Reduced the size of HPHP::VM::Iter from 64 bytes down to 32 bytes.
4) Removed the "if (siPastEnd())" check when adding a new element to an
HphpArray or a ZendArray.
5) Moved all of the iterator logic into a single .cpp file.
This diff reworks FullPos's to point to current element instead of pointing
to the next element. It also splits up the IterFree instruction into two
instructions (IterFree and MIterFree). These changes allowed various logic
to be simplified and data structures to be reduced in size. There is
definitely more opportunity for refactoring, but I know the JIT helpers for
iteration have been carefully tuned and so I'll leave further refactoring
for future diffs.
Finally, I spent a little time cleaning up the bytecode spec a bit, mostly
with respect to iteration.
This change is mostly for FB internal organizational reasons.
Building is not effected beyond the fact that the target now
lands in hphp/hhvm/hhvm rather than src/hhvm/hhvm.
Tim Starling